waterbug book a guide to the freshwater macroinvertebrates of temperate australia

THE

BOOKWATERBUG

John GooderhamEdward Tsyrlin

A guide to the freshwater macroinvertebrates

of temperate Australia

THE

BOOKWATERBUG

Text, illustrations and photographs (except where stated otherwise)© 2002 John Gooderham and Edward TsyrlinReprinted 2003

All rights reserved. Except under the conditions described in the AustralianCopyright Act 1968 and subsequent amendments, no part of this publicationmay be reproduced, stored in a retrieval system or transmitted in any form orby any means, electronic, mechanical, photocopying, recording, duplicatingor otherwise, without the prior permission of the copyright owner.Contact CSIRO PUBLISHING for all permission requests.

National Library of Australia Cataloguing-in-Publication entry

Gooderham, John.

The waterbug book: a guide to the freshwater macroinvertebrates of temperate Australia

Bibliography.Includes index.ISBN 0 643 06668 3 (paperback).ISBN 0 643 09003 7 (eBook).

1. Freshwater invertebrates – Australia – Classification.2. Freshwater ecology – Australia.I. Tsyrlin, Edward. II. Title.

592.1760994

Available from:CSIRO PUBLISHING150 Oxford Street (PO Box 1139)Collingwood VIC 3066Australia

Telephone: +61 3 9662 7666Freecall: 1800 645 051 (Australia only)Fax: +61 3 9662 7555Email: [email protected] site: www.publish.csiro.au

Set in Minion 9.5/11Cover design by Jo BirtchnellText design by James KellyPrinted in Australia by Impact Printing

Preface vi

Acknowledgements vii

Introduction 1

Key to macroinvertebrate groups 20

Freshwater sponges (Porifera) 32

Freshwater jellyfish and hydra (Cnidaria) 34

Unsegmented worms 36

Freshwater leeches (Hirudinea) 41

Segmented worms (Oligochaeta) 44

Freshwater snails, mussels and clams (Mollusca) 46

Freshwater mites and spiders (Arachnida) 59

Microcrustaceans: water fleas, copepods, clam shrimp and seed shrimp 63

Assorted crustaceans: amphipods, isopods, syncarids, brine shrimp and tadpole shrimp 68

Freshwater shrimp, prawns, crab and crayfish (Decapoda) 77

Springtails (Collembola) 84

Aquatic caterpillars (Lepidoptera) 86

Scorpionfly larvae (Mecoptera) 88

Toebiters (Megaloptera) 89

Spongefly larvae, lacewing larvae (Neuroptera) 90

Beetles (Coleoptera) 92

Flies, true flies (Diptera) 112

Mayflies (Ephemeroptera) 131

True bugs (Hemiptera) 144

Dragonflies and damselflies (Odonata) 161

Stoneflies (Plecoptera) 180

Caddisflies (Trichoptera) 187

Listing of SIGNAL grades 213

Glossary 215

References 219

Index 227

Contents

Most people are familiar with yabbies, mudeyes and water boatmen, but these are onlya small sample of the ‘waterbugs’ thatinhabit our lakes, streams, billabongs,wetlands, farm dams and even neglectedswimming pools.

This book aims to introduce the often-ignored diversity of freshwatermacroinvertebrates that can be found intemperate Australia. It will help amateurnaturalists, fishing enthusiasts, Waterwatchmembers and school students to identifyfreshwater macroinvertebrates, whileproviding a rapid reference for professionalstream ecologists.

The introductory chapters cover somebackground information about freshwaterecology and freshwater environments.The rest of the book is devoted toidentifying macroinvertebrates andproviding information on specific groups.Different sections contain different levels ofinformation, so people who are learningabout stream invertebrates for the first timecan use the illustrated key to groups offreshwater macroinvertebrates or simply leafthrough the pictures. Those with moreexperience can continue through to a moreprecise identification by following the keysincluded at the end of each group section.

Freshwater invertebrates can form a miniecosystem that fits inside a classroom fishtank and provides students with dramaticexamples of foodweb ecology and animalbehaviour. They also provide a valuableopportunity for students and communitygroups to try their hand at environmentalassessment.

Water management bodies such asMelbourne Water, the EnvironmentProtection Authority, Victoria, and Hydro Tasmania commonly use streaminvertebrates as biological indicators ofriver health in monitoring programs.While the sophisticated methods of theseorganisations are beyond the scope of mostWaterwatch or school groups, the SIGNALscore method (see page 19), provides areliable ‘back of an envelope’ method forconducting small-scale river healthassessments.

Preface

Acknowledgements

The authors would like to thank MelbourneWater, EPA Victoria and Hydro Tasmaniawho kindly sponsored the pre-pressproduction of this book.

The following people helped edit the bookin an attempt to free it from a mixture oftechnical inaccuracy and gibberish:Ellen Jerie, John Dean, Richard Marchant,Lester Cannon, Alastair Richardson,Nick Alexander, Ros St Clair, Helen Otley,Juliet Chapman, Gabrielle Balon, BridgetteDwyer, Fred Govedich, Katriona Tsyrlin,Brian Smith, Paul Gooderham, JaneGooderham, Lucy Gooderham, Tom Sloane,Rob Sloane, Rob Walsh, Kathryn Jerie,Geoffrey Smith, Jackie Griggs, GuntherTheischinger, Chris Watts, Jeff Meggs,Tom Weir, Peter Cranston, Penny Greenslade,Tina and Cameron, Michael Jerie, HelenWren and Phil Mitchell. Jessica Bakkerhelped with a very early version of the bookand Rachel Eley thought up the title.

Several photographs were kindlycontributed from other sources. These arespecifically acknowledged in their captions,but thanks go to Brian Smith, Gen-yuSasaki, Niall Doran, John Hawking, KarlieHawking, John Trueman, Caroline Dearsonand Kathryn Jerie. Technical photographicassistance was provided by David Humfrey,Arthur Wall and the team from MedicalIllustrations at Monash University.C. Riley Nelson shared with us his secrets of bug photography. Preserved specimenswere borrowed from Alena Glaister,Rhonda Butcher, DPIWE Tasmania,

Water EcoScience, The Water Studies Centre(Monash University) and EPA Victoria.Most of them knew about it.

A number of people helped to push-startthe book in its early days. These include:Richard Marchant, John Dean, Ros St Clair,Suzi Milburne, Rhonda Butcher,Brian Bainbridge and the team from theMerri Creek Management Committee.Nick Alexander was an invaluable navigatoronce it started rolling.

Our families have been supportive (likeauthor’s families usually are) but they havealso rolled up their sleeves and helped withdiagrams, editing and photography. Thankyou Kathryn Jerie and Katriona Tsyrlin.Perhaps we can go away on weekends now?

Condominium Creek in Tasmania’s south-west is a small, almost pristine river.

Introduction l 1

Finding freshwater invertebrates

Most freshwater macroinvertebrates arequite small but many can still be seen withthe naked eye. You can find them in twomain types of water: running water (lotichabitats) and still water (lentic habitats),but these can be broken up into differentfreshwater environments.

Springs, streams and riversSeeps or springs are very small trickles ofwater, often at the very beginning of streamswhere groundwater comes to the surface.Most streams can run underground for atleast some of their length and many will gounderground several times throughout theirlength depending on how permeable therocks beneath them are. Most of the animalsfound in seeps are able to burrow back intothe ground when flows drop and the waterrecedes underground. Sometimes thesefeatures can be connected to nearby cavesystems.

Streams and rivers are often broken intosections of fast/turbulent flow and slowflow. The fast turbulent bits are morecommon in steep headwaters and aretermed riffles. The slow patches betweenriffles are called pools if they are very slow,or runs if they are clearly flowing but fail tobreak the water surface up into whitepatches. Lowland rivers tend to be acombination of pools and runs due to theirgentle slope. Riffle animals tend to live onand under rocks in the stream, where they

hold onto the streambed to resist beingwashed downstream. In the more gentlesections of rivers, animals are more likely tobe free-living and swim around in the watercolumn. In many ways, the fauna of riverpools can be quite similar to the fauna ofponds and billabongs.

In all of these environments, areas withaquatic vegetation, leaf litter and woodydebris provide habitat for a diverse range ofanimals. Even irrigation channels can providea place to live for some of the more tolerantgroups of freshwater macroinvertebrates.

Introduction

Freshwater macroinvertebrates are a diverse group of animals, ranging from wormsand leeches to crustaceans and insects. You can encounter them when fishing, hiking,or bird watching, and you don’t have to study them intensively to appreciate them.

Taffey’s Creek in Tasmania is a blackwaterstream. The colour comes from rottingvegetation or peat upstream.

l The Waterbug Book22

Puddles, dams, billabongs, ponds and lakesBillabongs are sections of river curve thathave been cut off from the main channel asthe river moves around on its floodplain.For this reason they often have a fauna thatis halfway between the flowing riversdescribed above and the ponds and lakesdiscussed later in this section. The longerthey are cut off from the river, the morepond-like their fauna will become.

Still waters with no connection to streamsor rivers have a fairly simple fauna.They can only be colonised by animals that can fly to them, so they tend to bedominated by midges and other flies suchas mosquitoes. Once these are established,the predators invade: bugs and beetles andthe odd dragonfly. If the water stays for areasonable length of time, other animalswill find their way to it and the fauna will eventually include caddisflies and other insects.

Puddles, dams, old swimming pools andponds will all develop in a similar way.Aquatic vegetation, leaf litter and woodydebris will provide extra habitatopportunities and increase the diversity of animals found in any of theseenvironments.

Lakes usually have rivers flowing into andout of them, so they often share some ofthe river’s fauna, but they also have theirown distinct fauna. Lakes offer a diverserange of depths and these support differenttypes of aquatic plants which in turn offerdifferent habitat opportunities for a range of different animals.

A farm dam, despite its rural settings, can befull of aquatic life. A ring of last year’s rushesshows the level of the water during summer.

A billabong in northern Victoria. Sometimes thisdrying pool is connected to the nearby river.

Even a small creek that cuts its way through apaddock can host a thriving waterbugcommunity.

Introduction l 3

Wetlands, swamps, and marshesMost of these habitats spend some period of their time dry. This means that theirinhabitants either have to re-invade thewater once the dry period ends, or surviveby resting in the soil. Insects tend to re-invade, but a range of specialist crustaceansexist that have small drought-tolerant eggs.

The fauna within these environments variesgreatly and wetlands are some of the mostdiverse freshwater habitats in south-easternAustralia. These habitats also support a verydiverse range of aquatic plants.

EstuariesAn estuary—a place where the river meetsthe sea— is usually considered a marineenvironment, but in their upstreamsections, estuaries can have a mixture offreshwater animals that can tolerate somesalt, and saltwater animals that can toleratefreshwater.

Estuaries can be difficult places to study asthey are so dynamic, but this just makesthem more interesting. As always, aquaticvegetation, leaf litter and woody debris willincrease the diversity of animals found inthese environments.

Catching freshwatermacroinvertebrates

Pick up a stone or a piece of submergedwood in your nearest creek. Turn it over andlook closely. The creatures that scatter underthe thin film of water can be washed into ajar or a tray, and this will let you get a closerlook at them.

If you want to look at a larger range ofanimals, it is best to use a net. A butterflynet is not strong enough. A good aquatic nethas to have a strong handle and a flat edgeso that you can get close to the bottom-dwelling animals.

If you don’t have a net, an old sieve attachedto a broom handle will do the job. If you puta piece of old stocking over the sieve andsecure it with rubber bands it makes themesh finer, and you can catch smalleranimals.

You will also need a tray to help separate the animals from the sand, mud and debris.An old white photographic tray is ideal.Alternatively you can use a light colouredkitty litter tray.

Large lakes such as Lake Seal in Tasmania cansupport a mixture of lake and river animals.

Hazelwood’s Lagoon fills when the Clyde Riverfloods — an increasingly infrequent event. Itdries up to a few muddy patches over summer.


Finally you will need tweezers, large-mouthedpipettes (or a turkey baster), small plasticspoons, and fine paint brushes to pick upthe animals. Tweezers can often damagefragile animals so if you intend to keep yourcaptives alive use pipettes, spoons andbrushes. Large insects and crayfish can bepicked up by hand. If you want to see thesmaller creatures, you will need a goodmagnifying glass as well.

When using a net in fast-flowing water witha rocky riverbed, hold the net firmly in avertical position against the bed with itsmouth facing upstream. Lift and stir stoneswith your hands or a booted foot justupstream of the net. A cloud of debris anddislodged stream invertebrates will bewashed into the net.

In slow or still water stir the bed and scoopup the debris or sweep the net throughsubmerged vegetation. Many invertebrateslive on submerged wood and debris.

You can brush and rinse the pieces of woodover the tray or net. Heavy logs can bescrubbed in the water while holding yournet close downstream.

You will end up with a mixture of debrisand macroinvertebrates in the net.To separate them, fill up a third of yourwhite tray with water and empty thecontents of the net into it. It is importantnot to collect too much in one go so thatthe amount of debris does not cover morethan half the area of the tray. Now getcomfortable, and sort slowly through thetray, moving all the animals you find to aseparate container or an ice cube tray sothat you can look at them later.Professional stream ecologists call thisprocess ‘bug-picking’. A magnifying glassand a smaller container or jar will come inhandy if you want to observe live animalsin the field, but your observations don’thave to stop when you go home. You canset up a fish tank at home and as long asyou keep it aerated and only keep animalsfrom slow-flowing or still water, it will beeasy to maintain. It is difficult to believe,but even urban creeks have enoughcreatures to fill up your fish tank withaquatic life.

A selection of nets. Most professional nets haveflat bottoms.

Bug-picking tools include an ice cube tray forholding waterbugs, a plastic spoon, tweezers, a pipette and two different magnifying glasses.

Introduction l 5

Preservation and labelling

You can identify the invertebrates you findusing this book in the field, or you canpreserve them for identification later.Professional stream ecologists use 70%ethanol to preserve their animals. This canbe expensive, but a mixture of 75%methylated spirits with 25% water worksalmost as well. If you think you have foundunusual or interesting animals contact yourlocal naturalist club, Waterwatch group orstate museum. However, to make yourinformation valuable try to put only onegroup of invertebrates in a vial or jar andclearly label it. (Soft pencil on thick paperwill not rub off.) Include information about the exact location, such as the nameof the river or pond and the name of thenearest geographical feature such as a road,township, bridge etc. Also include the dateand the name of the person who collectedthe specimen, as this will allow scientists tofind you if they need to ask more questions.

Never take more animals than you need andreturn the leftovers to the place where youfound them.

Introducing freshwater ecologyWhether you step into a puddle or a river,you are entering a world which is every bitas complex as the large terrestrial eco-systems we are more familiar with. Thanksto David Attenborough, most people arefamiliar with the ecology of the SerengetiPlains in Africa even if they have spent theirentire lives in Sydney. In the Serengeti,hordes of herbivores (wildebeest and zebra)roam the grasslands, grazing on plants,while a smaller number of predators (lionsand hyenas) kill and eat them. The vulturesand carrion beetles that help themselves tothe lion’s dinner add layers to a structurewhich ecologists have named the foodweb.

The foodweb is a concept that explains howdifferent organisms within an ecosystem

The Huon Valley Waterwatch group practising their sampling technique on the Mountain River.


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Predators

Herbivores /Detritivores BacteriaProducers

Nutrients

Bacteria

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Leaf litter & periphyton

macrophytes periphyton

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Detritus

Figure 1. A ‘foodweb’ depicts the flow of energy or nutrients, starting with the sun in the top left.The pattern is fairly circular, with the detritus from herbivores, detritivores and predators ultimatelyproviding nutrients for the producers. In the real world, things are a lot more complicated than this.

Introduction l 7

feed upon one another. Figure 1 shows ahighly simplified foodweb from a stream.The various levels in the foodwebcorrespond to the various ecological ‘jobs’within an ecosystem, while the arrows showthe movement of food between organismswithin the system. Similar jobs exist inponds, rivers, and on the Serengeti Plains.The animals that occupy these positions willbe different in each system—for examplelions and dragonfly larvae—even thoughtheir function can be much the same.

Job description: producersAt the bottom of the foodweb areorganisms such as algae, plants and bacteriawhich create their own energy fromsunlight and/or raw chemicals that areavailable directly from their surroundings.These are called producers, as they takeresources that other organisms cannotreadily use, and produce energy in a formthat can be readily used by organismshigher up the foodweb. Unfortunately forthem, this usually involves being eaten. Instream environments, the three dominantforms of producers are: ordinary plantswhose leaves fall into the water, aquaticplants or macrophytes (from the Greek,macro = large, phyton = plants), andperiphyton (peri = edge, phyton = plants),which is a thin, slippery layer of algae andbacteria which coats stones and othersurfaces in streams.

Job description: herbivoresHerbivores occupy the next level up on thefoodweb. They eat producers. The two basictypes of herbivores present in streams aredescribed by the way they eat. Scrapersgraze periphyton, scraping the thin layer ofalgae from rocks and other hard surfaces.This group includes many aquatic snailstogether with a variety of otherinvertebrates equipped with brushes orblades on their mouthparts for removing

the firmly attached algal layer. Shredderscan sometimes eat macrophytes, by chewingthrough leaves or boring into the stems ofthe plants, but most consume old, dead,rotting plant material or detritus. Thismakes them detritivores as well asherbivores.

Job description: predatorsPredators are generally larger invertebrates,such as dragonfly larvae (Odonata) anddobsonfly larvae (Megaloptera) and largeranimals such as fish, frogs, and birds. Theyget their energy by devouring other animals.Their victims can be herbivores,detritivores or other predators.

Job description: detritivoresDetritivores eat a mixture of leaf litter,woody debris, and the bodies of deadorganisms. When organic matter first entersthe stream it tends to be large and chunky(see Figure 2).

The detritivores that deal with coarse debrisare shredders. They break it down into

Even the largest predators are prey for fish andbirds. Most dragonfly larvae spend half theirlives hunting and the other half being hunted.


Collectors

Scrapers

Shredders

Producers

periphyton & leaf litter

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smaller pieces, while extracting whatnutrients they can from a combination ofthe old plant matter itself and the bacteriaand fungi that grow on it.

Many detritivores are also herbivoresbecause the mouthparts and digestive

systems needed to eat live or dead plantmaterial are so similar. Animals such asyabbies (Parastacidae) will eat just aboutanything: animal or plant, living or dead.

As organic matter moves downstream, it ischewed and digested into smaller and

Figure 2. Animals break down leaf litter and other organic matter. Different animals use leaf litter indifferent ways, depending on how broken up it is and how much periphyton it has growing on it.

Introduction l 9

smaller pieces, until it becomes a cloud ofparticles. The detritivores that utilise thisform of organic matter are collectors (orfilter feeders). Many of these havespecialised hairs on their legs or aroundtheir mouthparts which strain the fineorganics from the water as it flows pastthem. Some examples of collectors includeblack fly larvae (Simuliidae), and somestick-dwelling caddisflies (Leptoceridae).

Foodweb loopsWhile organic matter is broken down bydetritivores, its smaller, basic componentsare released back into the water in the formof nutrients (various states of carbon,nitrogen and phosphorous) where they areused by producers, thus completing one ofthe loops of the foodweb. The wasteproducts of predators also find their wayback to the base of the foodweb where theyare used by producers.

LifecyclesMost invertebrates follow a simple lifecycle.They hatch from eggs and spend some timedeveloping. Once the larvae or nymphshave grown, they become adults, reproducesexually and lay eggs from which youngemerge to start the cycle again. However,some invertebrates employ moreinteresting methods of reproduction, suchas fission and hermaphroditism. Fission isused by animals such as turbellarianflatworms, sponges (Porifera) and hydra(Cnidaria). They can split into multipleindividuals voluntarily, or can recover frombeing cut up by predators or scientists.Each separate piece becomes an individualanimal.

Hermaphrodite reproduction is used bysome snails (Gastropoda) and leeches(Hirudinea). Individuals have both maleand female organs so that each of thepartners can lay fertilised eggs.

GrowthAll invertebrates grow, but they vary greatlyin the way that they do it. Leeches and snailshave skins that can grow at the same rate asthe rest of the animal. They simply getbigger as we do. Crustaceans and insects(Phylum Arthropoda) have externalskeletons, and these don’t grow much oncethey have hardened. To avoid being com-pressed inside their own skins, arthropodsfrequently shed their skins, replacing the oldones with the next size up. Some arthropodscan have as many as 50 skins in a lifetime.

Most freshwater macroinvertebrates start life aseggs. The eggs on the underside of this streamcobble are surrounded by a thick protectivelayer of jelly.

The male giant water bug (Belostomatidae) hashis back covered with eggs by the female. Thiskeeps them safe from predators and dad can’treach them either.


Many of the invertebrates in streams areinsects. During the course of their lives theychange from a young wingless insect into afully winged adult. There are two ways thatthis amazing change can happen: the larvallifecycle or the nymphal lifecycle.

Larvae have soft, simple bodies when theyare young and usually look nothing like theirparents. They are sometimes such simplified

eating machines that they even lack legs.When larvae reach a size that will convertnicely into a healthy adult insect, they entera ‘pupal’ phase. During this phase theytransform themselves into winged adults.

The pupa is a deceptively simple shell insidewhich the insect is rebuilding itself in adultform. Adults can emerge from the pupalskin while it is submerged, or in some cases

The waterboatman nymph changes gradually asit grows until its wings are large enough to use.

The chironomid larva (Chironomus sp.) has asimple body. It goes through a pupal phase inorder to turn itself into a winged adult.

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Larval lifecycle Nymphal lifecycle

Introduction l 11

the pupa can move and swim to the surfacewhere the adult struggles from the splitpupal skin.

Nymphs generally resemble their parentsquite closely, and simply lack the adult’s

wings and size. Small nymphs start withwing buds which grow with the animal, toeventually become fully developed wings.

Some nymphs leave the water when theybecome adults. The nymph crawls out of

A mosquito pupa (Culicidae) has breathinghorns that puncture the water surface andreplenish the pupa’s air supply.

A tipulid pupa (top) and an empidid pupa showhow fly pupae vary greatly in shape.

Conoesucid caddisflies pupate inside theircases after sealing the ends with a silk disc.

The black fly pupa constructs a harness thatkeeps it from being washed away by thecurrent.

A mobile caddis pupa swims to the surface toemerge. The swimming hairs on some of its legshelp to push it through the water.

A hydrobiosid caddisfly encased in its fine silkpupal sheath is protected by a layer of finegravel and is stuck to the underside of a rock.

Different types of pupae


the water, splits down the back, and stepsout of its skin. The emerging insect isalready fitted with a pair of wings, which itthen inflates with ‘blood’. The new wingsare very soft at first and must hardenbefore the animal can use them to fly.This can take about an hour. During this

time their bodies are soft too and they arevulnerable to predators.

Some insects such as true bugs and beetleswill return to the water to live as adults,while others cannot and will only ventureback to lay eggs and die.

The stonefly nymph (Trinotoperla minor) crawls from the water (top left) and begins its strenuouschange into a winged adult.

1

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3 6

5

4

Introduction l 13

Waterbugs and us—from feasting tofly tying

People notice things quickly if they arepainful, uncomfortable or annoying.Freshwater macroinvertebrates can be allthree and it is likely that this is how humansfirst noticed them. Even today, we know alot more about the insects that bite, blindand infect us with diseases than we do abouttheir less troublesome relatives.

Some of the most painful freshwatermacroinvertebrates are true flies or Diptera.Members of this group include mosquitoes(Culicidae), black flies (Simuliidae), bitingmidges (Ceratopogonidae) and horse flies(Tabanidae), all animals that are known for their bites. Medical entomology was inmany ways one of the more appliedbeginnings of freshwater ecology.Controlling these species involved learningabout their ecology and biology. As noted byH.B.N. Hynes in his essay on ‘aquatic insectsand mankind’ many of the problems withthese animals stem directly from ourmodification of their original habitat.Mild organic pollution can benefit the larval stages of many of the more tolerantaquatic fly larvae, and humans and livestockprovide plenty of opportunities for theblood-sucking adults. As a result, many ofthe wetlands and streams in rural and urbanareas offer prime conditions for a lot ofthese species to become pests.

Biting backFreshwater invertebrates might benoticeable when swarms of them are eatingus but in some parts of the world humansget the better of invertebrates and dine onthem instead. Singly, few invertebrates offerenough muscle to be a meal, but when theyswarm, insects can occur in large enoughvolume to be an important source of food.David Livingstone, the famous explorer,encountered a form of cuisine on the banksof Lake Malawi (Nyasa) in Africa, which

involved collecting large quantities ofphantom midges (Chaoborus edulis), boilingthem and forming them into patties. Theend product was said to taste a little likecaviar. In Mexico, two species of water-boatmen (Corisella edulis, C. mercenaria)suffer a similar fate. Their names reflecttheir edibility and their market value (asdried goods) respectively.

The North American Indians are alsothought to have taken advantage of fliesfrom the families Athericidae andEphydridae. These were harvested as theygathered on streamside vegetation to layeggs and baked into small cakes and storedas winter provisions. In Rawa Lamongan,Indonesia, one of the local dishes providesan example of individual invertebrates thatare large enough to be eaten singly. Largewater beetles (Dytiscidae) are trussed upwith grass stems and grilled in a fire. Thehard shell acts as a bowl and the animal iseaten a bit like an oyster once the wingcovers have been removed. Westerners areperhaps a little more comfortable eatingcrustaceans such as yabbies, freshwaterprawns and shrimp. In southern Vietnam,one of the more novel crustacean dishesinvolves freshwater shrimp in a cold, clearsoup. This simple dish rates a mention asthe shrimp are served alive and have to bepursued around the bowl. ‘Dancing shrimpsoup’ is not a dish for hungry or impatientpeople.

Most aquatic invertebrates are edible.Exceptions include freshwater mites,flatworms and some of the waterbugs, asthese animals have pores in their skin whichexude foul-tasting or toxic substances. Thetaste of most invertebrates is often muchsubtler than their texture and few Westernpeople can stomach the combination ofcrunchy, leathery outsides and liquidinsides. We have tried blind tasting caddisflyadults to see if different families could beseparated based on their taste.


We found that they couldn’t, but that theleptocerids with their long wings andantennae were a choking hazard. This mustbe why winged insects are usually singedover a fire before they are eaten.

Lures and fliesWestern society often shuns the eating ofmacroinvertebrates but is partial to fish,particularly the large predatory species suchas cod, bass, perch and the introduced troutand salmon. Macroinvertebrates make upthe main diet of most freshwater fish, andfor this reason they dominate the bait usedwhen fishing, either as live baits or asreplicas such as lures or flies. Knowing alittle bit about the ecology and life history of freshwater macroinvertebrates hasallowed us to refine the sports of lure andfly fishing.

The earliest use of lures or flies is thought todate back to the twelfth century in Europe.These originally crude lures were simplywool or feather-covered hooks, but theydeveloped until they became the intricatelyassembled flies described by Izaak Walton in his famous seventeenth-century text The Compleat Angler. Flies are constructed

primarily from fur and feathers tied andtwisted to resemble almost every imaginablemacroinvertebrate (with the exception offlatworms). Flies can even be constructed to imitate the various life stages of differentanimals. A good example of this can befound with the angler’s favourite streaminsect: the mayfly. Wet flies are heavyenough to sink and this allows them tomimic the aquatic nymphs of mayflies, dryflies rest on the surface, tempting the troutwith the image of a mayfly struggling freefrom its nymphal skin and trying to come to terms with flight. Different dry flies canbe made to represent emerging mayflies,females laying eggs by dipping theirabdomens in the water, or spent mayflies,exhausted by their reproductive efforts andflopping spent against the surface of thewater.

Two concepts are used to make a fly work(or blamed for its failure). The first is theaccuracy of the imitation and the second isthe timing of the fly presentation.A successful fly is taken by a fish because it looks like a real macroinvertebrate.The theory goes that a fly that lands on thewater, by itself, is considered as anindividual and therefore scrutinised moreheavily by a fish. A fly that lands on thewater during a swarm of food that the fishare currently eating is taken because it isalready recognised by the fish as food.For this reason, fly fishing has developedaround ‘matching the hatch’. This involvesusing a fly that resembles the originalinvertebrates or ‘naturals’, but also using theright fly at the right time. Finding out thissort of information has forged a strong linkbetween anglers and freshwater scientists.The angler’s obsession with some of theseinvertebrates has given birth to someinteresting biological studies and alternately,fly fishing has allowed a number of eminententomologists to mix their work and play.

A selection of fishing flies.

Introduction l 15

Some flies can be very small. This pair (left) imitates a chironomid, or non-biting midge, and itspupa (right). They are less than a centimetre long.

This fishing fly (left) copies the pose of a spent mayfly (right), lying with its wings flat against thesurface of the water.

The hairs of this fly (left) don’t imitate the legs of an adult caddisfly exactly but they bend thesurface of the water in a similar way and stop the hook from sinking.

This fishing fly (left) is weighted so that it sinks and moves under water like the nymph of the mayflyColoburiscoides that it imitates (right).


Studying freshwatermacroinvertebrates

People have, at times, been interested infreshwater invertebrates simply becausethey are fascinating to study. One of thefirst documents written about freshwatermacroinvertebrates in any detail, waspenned by a Scottish doctor by the name of Thomas Moufet in 1634. In his textInsectorum sive minimorum animaliumtheatrum (roughly translates as: Insects orsmall animals on show), he wrote aboutthe natural history of insects including thewater scorpion (Nepa sp.) and the streamcaddisflies of Scotland. He is possibly bestknown through his daughter, the originalMiss Muffet (an anglicised version ofMoufet) who features along with one ofher father’s specimens in the famousnursery rhyme.

Over the next two hundred years, the studyof invertebrates was pursued by scientistsfrom around the world and an impressivebody of knowledge took shape. Freshwaterinvertebrates often feature in these earlyworks as they were easy to find and keep incaptivity. One of the first books written inEnglish to concentrate on freshwatermacroinvertebrates was written in 1895 and it was simply titled ‘The natural historyof aquatic insects’ by its author L. C. Miall.In it he summarises his own work along withthe studies of other people from the first 200years of research into what was becoming apopular branch of natural history.

From fairly simple beginnings, the study offreshwater macroinvertebrates hasdiversified and changed focus throughoutits history. As mentioned earlier, medicalentomology provided some of the firststudies in this field. Australia was not farbehind the rest of the world, with the firstofficial descriptions of its mosquito faunabeing put to paper as early as 1835 by a

fellow named Westwood, publishing in theannals of the French Entomological Society.Soon, the study of Australia’s freshwatermacroinvertebrates was well under way.Understandably the first animals to bestudied were large animals like the waterbeetles, which were catalogued by Clark asearly as 1862 and revised in 1882 by Sharp,along with the whirligig beetles. Othermacroinvertebrate groups didn’t lag farbehind. In the early 1900s Goddarddescribed a range of leeches and worms,while Sayce, Thomson and Smith turnedtheir attention to some of the scuds oramphipods and the more primitivecrustaceans of south-eastern Australia.

One of the most prolific contributors to this early bloom of freshwater science, wasR. J. Tillyard who, in 1917, published a largetome titled ‘The biology of dragonflies’.Tillyard went on to become the Chief ofCSIRO’s Division of Economic Entomologyand published extensively on the mayflies,caddisflies and stoneflies of south-easternAustralia.

Freshwater macroinvertebrates are stillstudied extensively in Australia though thesedays the research has diversified. Naturalhistory and taxonomic studies are lessprevalent and the emphasis is often on riverhealth (see page 19) or ecology, whichinvolves studying how different speciesinteract with one another and theirsurroundings.

Finding your way aroundmacroinvertebratesTaxonomists are the people who decidewhich animals are different enough to beconsidered species and given their ownnames. To do this they have developed alarge amount of technical language, orjargon, which they use to describe the partsof an animal’s body with great accuracy.

Introduction l 17

This also allows them to describe thedifferences between species more accurately.Rather than saying ‘the front part of themain section of the body’, taxonomists havea single word that contains all of thisinformation: prothorax. ‘Pro’ is ancientGreek for front, and ‘thorax’ is an ancientGreek word that originally referred to thepiece of armour known as the breast platebut is now used for the part of the bodybetween the head and the abdomen. Manytaxonomic terms are put together from amixture of ancient Greek and Latin, areminder of the origins of much of ourscience. Figure 3 gives some of thecommoner body parts that are used whenkeying out insects and other streaminvertebrates.

Taxonomists also have a set of words thatgive directions, a bit like the nautical termsport and starboard used by sailors. If ataxonomist was to refer to ‘the top of thefront part of the main section of the body’,they would say ‘dorsal prothorax’. Figure 4demonstrates some of the direction jargonthat is used. These words are easier toremember and also make more sense oncethey have been roughly translated, so wehave provided rough translations whereverpossible.

Taxonomic names: a system forclassifying animalsTaxonomic names consist of a genus nameand a species name, for example Homo(genus) sapiens (species). They identifyanimals as individual species, but they alsogive clues about which other species they aresimilar to. Species from the same genus areusually very similar. Classification is asystem that allows different groups ofanimals and plants to be separated from oneanother based on consistent differences inshape. For example, mayflies and stonefliesare so different that they belong to differentOrders (Ephemeroptera and Plecoptera),but are similar enough to come from thesame Class (Insecta).

Figure 3. The basic system of naminginvertebrate body parts.

Figure 4. The basic system for describingdirections and locating invertebrate body parts.

pro = in front meso = middlemeta = behindthorax =

‘breastplate’abdomen =

the hidden bits

ANTERIOR ante = ‘before’:the side beforethe animal

POSTERIOR post = ‘after’: the sideafter the animal.

DORSAL dors = ‘the back’

VENTRALventer = ‘the belly’

LATERALlateris =‘the side’

antennae

head

prothorax

mesothorax

metathoraxAbdomen(the abdominalsegments arenumbered 1–10,with 10 at the tipof the abdomen)


The examples in Table 1 are well knownanimals. Their classification reads down thepage and shows that they are from the samekingdom but different phyla. Note the use ofcapital letters for every level except speciesand the different endings on each of the levelnames. This convention allows scientists torecognise different classification levels, whenthey appear in written text.

Classification groups exist at a range oflevels. This book deals mainly with the bold

levels, especially the Family level. Familynames start with a capital letter and end in‘ae’. When they are referred to as commonnames, the ‘ae’ and the capital letter aredropped. Thus animals from the familyAeshnidae are referred to as aeshnids.

Why do taxonomic names change?Sometimes the taxonomic names in thisbook will be different to those in older books(and newer ones eventually). Often this isbecause the species, genus or family namehas changed. There are a number of reasonswhy this could happen, but the mostcommon is that taxonomists have changedthe way that they think the group of animalsis related to other similar animals.

If animals that were once thought to bedifferent are found to be quite similar, themore recently named animal takes the olderanimal’s name. If animals have beenseparated, then one or both will receive newnames.

Figure 5 shows how the mayfly, now calledNousia parva from Armidale, New SouthWales, has had its name altered by taxonomythat existed before it was even discovered.

Table 1. Classifications of two commonanimals

Kingdom Animalia Animalia

Phylum Arthropoda Chordata

Class Insecta Mammalia

Order Odonata Primata

Family Aeshnidae Hominidae

Genus Austroaeschna Homo

Species unicornis unicornis sapiens

Common name mudeye humans(a dragonfly larva)

Figure 5. The mayfly Nousia parva is an example of the way taxonomic names can change.

1918 1950 1985

Nousia delicata wasdescribed by Navás in Chile,South America. At this stageNousia was a new genus onlyfound in South America.

Meanwhile, Nousia delicata (the original Nousia) was changed to Atalonella ophisby Needham & Murphy in 1924. Navás changed this to Nousia ophis in 1925 andPescador and Peters changed it back to Nousia delicata in 1985.

Atalophlebia parva wasdescribed by Harker fromthe Gara River near Armidalein New South Wales.

Pescador and Petersexamined specimens fromSouth America and Australiaand decided that Nousiaexisted in both countries.Atalophlebia parva becameNousia parva.

Introduction l 19

Measuring water quality with theSIGNAL method

One very good reason for studying waterbugsis that they can be useful indicators of theecological health of freshwater habitats.Scientists have found that some macro-invertebrates are more tolerant to pollutionthan others. If a stream is polluted, tolerantbugs will usually be found in largernumbers than intolerant ones.

On the other hand, if a habitat is close to itspristine or natural condition, tolerant typesof bugs will be found alongside equal orgreater numbers of more sensitive ones.

The SIGNAL method uses these ecologicalpatterns to measure water quality usingwaterbugs. SIGNAL stands for StreamInvertebrate Grade Number – AverageLevel. By knowing the SIGNAL grade forevery family, scientists can calculate theSIGNAL score of a site and therefore forman objective opinion about its health.

Calculating a SIGNAL score for your siteStep 1. Make a list of the families you find atyour site and look up their SIGNAL gradeson pages 213–214. For example:

Eustheniidae 10Orthocladiinae 4Psephenidae 6

The higher grades are given to more sensitivefamilies and the lower grades to moretolerant families. The highest grade is 10 forsensitive families and the lowest grade is 1.

Step 2. Calculate the sum of individualSIGNAL grades: 10+4+6 =20

Step 3. Divide the sum by the number ofdifferent families you collected. We collected3 families, therefore 20/3 = 6.7

6.7 is the SIGNAL score for your site.

SIGNAL score and water healthThe following table provides a guide forinterpreting water health according to theSIGNAL score of a site.

higher than 6: healthy habitatbetween 5 and 6: mild pollution between 4 and 5: moderate pollutionless than 4: severe pollution

Our site scored 6.7 and therefore can beconsidered a site with clean water.

If you can only identify your waterbugs asfar as the order level, you can still use theSIGNAL score. Orders consist of manydifferent families, with a variety ofSIGNAL grades, so an assessment will bemuch more accurate with family levelidentification.

SIGNAL assessment is usually performed on a single sample from either a pool/edge,or a riffle and this keeps the methodconsistent and allows people to comparesites.

This method of assessing water health issometimes used by scientists andprofessional biologists. However, itsaccuracy depends on how well youconducted your sampling andidentification.

The SIGNAL method was originallydeveloped on very ‘normal’ streams andrivers and will not work as well forfreshwater habitats such as wetlands orlakes, or streams with strange (but natural)water chemistry.

If you are interested in this type ofinvestigation and need some help, your localWaterwatch group should be able to pointyou in the right direction. Ring your localcouncil to find out about Waterwatch orlook them up on the internet.


Keys are designed to separate animals intogroups and identify them. There are twotypes of key used in this book. The main keyto groups on the following pages works likea flow chart with illustrations, and will helpyou find the right chapter. Within thesechapters, the keys are more conventional.They are made up of pairs of opposingstatements or couplets. Each couplet isnumbered. The two statements within thecouplet describe different sets of features.To use the key, start with the first couplet,and choose the statement that best describesthe animal you want to identify, then followthe directions at the end of that statement toget to the next relevant couplet. Each choicenarrows down the number of possibilities,until you are left with a single name. Ifeverything works, this is the name of youranimal. The numbers in brackets refer to theprevious couplet. They allow you to retraceyour steps if you get lost, or if you havesecond thoughts about a choice. The keybelow is a simple example to give you a feelfor how they work. Choose any shape youlike and pretend that this is the animal you

are trying to identify. Now work through thecouplets and try to identify it.

If the key doesn’t seem to work for youranimal, browse through the photographsuntil you find a match and try workingbackwards. If it still doesn’t work, it is possiblethat you have a land invertebrate that hasbeen washed into the water. To check this,you can use one of the general invertebratereferences listed in the bibliography.

There are a few things to bear in mind beforeyou start using a key. Macroinvertebrates arequite small, and you will need to be able tosee the parts of the animal the key refers to,so if possible:

• use large examples of the animals youwant to identify,

• use a good quality magnifying glass (5–10 x magnification),

• place your specimen in shallow water,it won’t distort your view,

• use a clean white background (or blackif it’s a light coloured animal), and

• make sure you have plenty of light.

1 Sides straight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3(go to line 3, missing line 2)

Sides curved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2(go to line 2)

2(1) Length and width the same . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CIRCLELength and width different . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OVAL

3(1) Three sides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TRIANGLEFour sides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) Length and width the same . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SQUARELength and width different . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RECTANGLE

A key to shapes

Key to macroinvertebrate groups

Key l 21

START

is the animal a pupa? (see pictures on page 11)

GO TO PAGE 29

MicrocrustaceansCLADOCERA/COPEPODA

(page 63)

GO TO PAGE 22

with wings, or is clearly a beetle/true bug

(see pictures on pages 92 and 144)

without wings

usually smaller than 3 mm,compact shape, moves jerkily

not a cladoceran or a copepod

with legs

with jointed legs with stumpy pro-legs only

without legs

True fly larvae DIPTERA(page 112)

GO TO PAGE 25A


attached to a solid surface

(from page 21)

with tentacles without tentacles, encrustsstones and wood

slender, without a suction cup stout, with a distinctive suctioncup at one end

without a hard shellwith a hard shell

GO TO PAGE 23BGO TO PAGE 23A

free to move, not a jellyfishfree to move, like a small jellyfish

Freshwater spongesPORIFERA (page 32)

crayfish symbiontsTEMNOCEPHALANS

(page 40 )

Hydra CNIDARIA (HYDROZOA)

(page 34)

Jellyfish CNIDARIA (page 34)

Key l 23

Shell with two ‘halves’

segmented

with suction cups on either end of the body

and with a head capsuleand without a hardened head capsule

without suction cups

not segmented

single shell, often coiled

shell contains a soft legless body shell contains lots of legs

Seed shrimp and clam shrimpOSTRACODS/CONCHOSTRACA

(page 66 and 67)

Mussels and clamsBIVALVIA(page 46)

Leeches HIRUDINEA

(page 41)

Snails GASTROPODA

(page 52)

Black fly larva DIPTERA

(page 129)

A(from page 22)

B(from page 22)

GO TOPAGE 24A

GO TOPAGE 24B


Flatworms TURBELLARIANS

(page 38)

True fliesDIPTERA

(page 112)

Crayfish symbiontsTEMNOCEPHALANS

(page 40)

Proboscis wormsNEMERTEA

(page 37)

Round wormsNEMATODA

(page 36)

Horsehair/gordian wormsNEMATOMORPHA

(page 37)

shorter than 1.5 cm tapering longer than 1.5 cm

with a snout, fleshy without a snout, wiry

with hard mouthparts (these can beinside the head and difficult to see)

without hard mouthparts

GO TO PAGE 25B

flattened, short and slimy

with tentacles (usually found onfreshwater crayfish)

A(from page 23)

B(from page 23)

not flattened, long and thin

withouttentacles

Key l 25

Spiders and mitesARACHNIDA

(page 59)

Mountain shrimpSYNCARIDA

(page 73)

Segmented worms OLIGOCHAETA

(page 44)

Springtails COLLEMBOLA

(page 84)

AssortedCrustaceans

Crayfish, shrimp, crabsand prawns DECAPODA

(page 77)

POLYCHAETA (not coveredin this book)

Millipedes MYRIAPODA(not coveredin this book)

with paired fleshy projectionsand palps (rare and small)

without paired projections, butsometimes with last half

covered in fine gills

with more than 10 legs(5 pairs)

with 10 legs with 8 legs

with 6 legs(some might be

covered by aportable case)

long animal, all legs similar short animal, legs varied

Often smaller than a pinhead,lives on water surface

usually longer than 3mm,unlike collembola

A(from page 21)

B(from page 24)

GO TOPAGE 26

GO TOPAGE 31A


True bugs HEMIPTERA(page 144)

Cased caddis fliesTRICHOPTERA

(page 187)

Aquatic caterpillarsLEPIDOPTERA

(page 86)

without a case

long legs, case never withcoarse vegetation attached

lengthways

with a case

GO TO PAGE 27GO TO PAGE 28

short, stumpy legs, case withcoarse vegetation attached

lengthways

with paired biting/chewingmouthparts (can be less obvious)

with wing buds, well developedcompound eyes, and legs

without wing buds, less welldeveloped eyes and legs

with piercing/sucking mouthparts fusedinto a single spike (usually obvious)

(from page 25A)

Key l 27

Beetle larvaeCOLEOPTERA

(page 92)

Scorpion fly larvaeMECOPTERA

(page 88)

Free living caddis fliesTRICHOPTERA

(page 187)

Dobson/Alder FliesMEGALOPTERA

(page 89)

Lacewing larvaeNEUROPTERA

(page 90)

(from page 26)

mouthparts straight and longer than headmouthparts short and curved

abdomen with 7 or 8 pairsof fleshy projections

abdomen with 10 or 0 pairsof fleshy projections

last abdominal segment withlarge hooked prolegs

last abdominal segment withoutlarge hooked pro-legs

body highly variable (can be flat, rounded,dark or pale) but never like Mecoptera

body long, thin and cylindrical, firstsegment with an orange/brown rectangle


Stoneflies PLECOPTERA

(page 180)

Dragonflies ODONATA (page 161)

Mayflies EPHEMEROPTERA

(page 131)

Damselflies ODONATA (page 161)

(from page 26)

with 2 tails with 3 tails or no tail

with 0 tails, jaw large andfolded away under head

with 3 tails

tails flattened, or broad, jaw largeand folded away under head

tails thin, round in crosssection

Key l 29

(from page 21)

forewings hard, coveringhindwings at rest

forewings hard and meeting inthe centre of the animal’s back,

mouthparts for chewing, or biting

forewings leathery, foldedasymmetrically, mouthparts form a

tube for sucking

forewings = hindwings, orwithout hindwings

two fully formed pairs of wingswith forewings only

without tails

GO TO PAGE 30A GO TO PAGE 30B

with tails

True flies DIPTERA

(page 112)

Adult beetlesCOLEOPTERA

(page 92)

True bugs HEMIPTERA(page 144)


wings fold flat against body

wings without scales,mouthparts not coiled

wings with scales,mouthparts long and coiled

antennae small, eyes large,wings held as shown

B(from page 29)

A(from page 29)

GO TO PAGE 31B

with 3 tails, wings held awayfrom body

wings (and body) covered inhairs, antennae as long, or

longer than body

with 2 tails, wings foldedalong back

wings with few hairs

CaddisfliesTRICHOPTERA

(page 187)

Dragonflies anddamselflies ODONATA (page

161)

Moths LEPIDOPTERA

(page 86)

StonefliesPLECOPTERA

(page 180)

Mayflies EPHEMEROPTERA

(page 131)

Key l 31

A(from page 25)

first segment doesn’tform a shield

B(from page 30)

7 pairs of jointed legs,plus simple leg-like

appendages

first segmentforms a shield

11 pairs of simpleleg-like appendages,swims upside down

last abdominalsegments fused

wings with lots of edge veins wings more sparsely veined

head without an elongated‘beak’

head elongated toform a ‘beak’

last abdominalsegments separate

Brine shrimpANOSTRACA

(page 75)

LacewingsNEUROPTERA

(page 90)

ToebitersMEGALOPTERA

(page 89)

Water slatersISOPODA (page 72)

Scorpion fliesMECOPTERA

(page 88)

Scuds or sideswimmers AMPHIPODA

(page 69)

Shield shrimpNOTOSTRACA

(page 76)

l The Waterbug Book32 l

Distinguishing characteristicsSponges are primitive organisms and do nothave any digestive, or reproductive organs.They are a rather peculiar colony ofspecialised cells that perform differentfunctions but share a common skeleton.The skeleton is a mesh of microscopicneedles, fibres and rods. The sponges sold inchemist shops are actually just skeletons.

Sponges are irregularly shaped, dull-coloured and can often be covered by ormixed with algae. Their body consists of acavity surrounded by convoluted walls ofsofter tissue, held together by the skeletonand covered with cells that move water withsmall whip-like structures (flagellae).

Porifera translates as ‘pore bearer’ and thebody wall has thousands of pores throughwhich the water is sucked in and blown outwhile the animal feeds.

Classification and distributionNine genera and 24 species of freshwatersponges have been recorded in Australia.Most of them occur in New South Walesand Queensland. Only one species has beenrecorded in Tasmania and Victoria. Twospecies occur in South Australia andWestern Australia. All of the freshwatersponges in south-eastern Australia belong tothe family Spongillidae.

Habitat and ecologyFreshwater sponges are found on theundersides and edges of rocks andsubmerged wood, usually as thin crusts ormats. Freshwater sponges prefer slowmoving, shallow waters, where there is asolid surface for them to grow on. Spongescan also occur in saline pools and in lakeswith slightly saline waters.

Sponges feed by filtering organic particlesfrom the water column. They draw waterinto the body cavity where various cellsstrain micro-organisms and organic debrisfrom it. Food particles are then transferredto other cells throughout the body. A large

Freshwater sponges (Phylum: Porifera, Family: Spongillidae)

Freshwater sponges are much smaller and less spectacular than their saltwaterrelatives. They are often confused with aquatic plants, algae or fungal growthbecause of their simple construction. In fact, until the eighteenth century, spongeswere not recognised as animals.

Freshwater sponges, 5–6 cm diameter. Thegreen colour is due to algae living symbioticallywithin the sponge.

Sponges l 33

quantity of food is absorbed by a sponge,and the larger marine species can filterseveral litres of water a day.

Natural historySponges can reproduce both sexually andasexually. When they reproduce sexually,they are hermaphroditic (one animal canproduce both male and female reproductivecells). Once fertilised, the egg develops intoa free-swimming larva propelled byspecialised microscopic hairs (cilia) until itfinds a suitable spot to attach and grow intoa new sponge.

Asexual reproduction can occur in severalways. Sponges can produce small round

lumps known as gemmules. Gemmules aresurrounded by a protective membrane andspicules, this allows them to surviveunfavourable conditions when the mainbody of the sponge is destroyed.

When conditions improve, the gemmuleshatch and grow to form sponges that aregenetically identical to the parent. Spongescan also voluntarily (or accidentally) splitand form more separate animals. They havean amazing ability to regenerate. Even whenground up and squeezed through a cloth thesmall fragments re-build themselves into anew sponge.

Freshwater sponges often encrust wood orrocks in streams. [Photos: K. Jerie]

l The Waterbug Book34 l

Distinguishing characteristicsThe freshwater cnidarian body plan is asimple sack with a mouth opening usedeither as an entry for food or an exit forwaste. Tentacles encircle the mouth and areused to catch food from the surroundingwater. Most are smaller than 30 mm.

The most common freshwater cnidarian isHydra, a solitary, sessile polyp. Sometimespolyps form a colony in which all polyps are connected to each other by thin stems.These colonies are often confused withplants because of their branchingappearance. Some freshwater cnidariansoccur as a medusa or jellyfish. These arevirtually the same as a polyp, but flattenedvertically and tipped upside down. Themedusa has its mouth opening underneathits body, surrounded by hanging tentacles.

Classification and distributionAll of the freshwater Cnidaria belong to the Class Hydrozoa. Four genera: Hydra,Cordylophora, Craspedacusta andAustralomedusa are found in south-easternAustralia.

HabitatHydra, the most common polyp, can befound in ponds, small lakes and mountainstreams. They attach themselves to stonesand submerged wood and can congregate in large groups. Colonial polyps(Cordylophora) also attach to wood androcks in flowing waters, ponds and lakes.

This group has been found in the salt watersof Lake Corangamite and even in theornamental lake at the Botanical Gardens,in Melbourne. The free-living jellyfish(Craspedacusta) is known from lakes andreservoirs throughout south and south-eastern Australia and was one of the firstanimals to appear in Canberra’s Lake BurleyGriffin. Curiously this freshwater medusa,the size of a 50-cent coin, has been found inbird baths.

EcologyAll cnidarians are predators. They usetentacles, armed with stinging nematocysts,to catch minute animals such as cladoceransand copepods.

Freshwater jellyfish and hydra (Phylum: Cnidaria, Class: Hydrozoa)

Most cnidarians live in the sea. The phylum includes some of the best known marineinvertebrates, the sea anemones and the colonies of coral polyps that created ourspectacular coral reefs. Jellyfish like the dreaded ‘blue bottle’ also belong to the Cnidaria.

A hydra, around 1 cm long, showing a tinyindividual budding from its parent.

Freshwater jellyfish and hydra l 35

While most freshwater cnidarians are sessile,Craspedacusta and Australomedusa freelyfloat in the water column. Hydra polypsmove around by slowly sliding the base oftheir body or by moving from their base totheir tentacles and back to the base again,like acrobats doing somersaults.

Natural historyThe name Cnidaria comes from the Greekword knide, which means stinging nettle.Cnidarian tentacles carry special cells callednematocysts, and these are responsible forstinging and killing prey. Nematocysts havea long, coiled, sometimes venomous orsticky thread attached to a harpoon-likehead and these are fired from the cells intoprey. In blue bottles, thousand ofnematocysts are powerful enough to kill afish and give humans a severe sting. However,freshwater cnidarians are absolutely harmlessas their prey are microscopic.

Cnidarians alternate between the polyp andmedusa life forms with the medusa usuallyproducing male and female reproductivecells and the polyps reproducing asexually.

In Hydra, the medusa stage is absent and thepolyp takes over and reproduces bothsexually and asexually by budding.Cordylophora, the colonial form, is simply acommunal variation on Hydra with a groupof polyps joined together after incompletebudding. In comparison, the lifecycle ofCraspedacusta and Australomedusa isdominated by relatively large and freefloating medusae, alternating with a minutehydra-like polyp.

Both the term Hydra andMedusa are from Greekmythology. The Hydra wasa many headed waterserpent that Heracles (orHercules) had to slay asone of his twelve tasks.Medusa was a powerfulmonster who had snakesfor hair. Her look couldturn her victims to stoneand she was eventuallyslain by another Greekhero, Perseus. Both animalslook a little like the originalmythical beasts, but on amuch smaller scale.

Hydra can be quite inconspicuous amongstvegetation. The tentacles form a deadly net tocatch unwary prey.

The freshwater jellyfish Craspedacusta sowerbyi measures lessthan 5 cm in diameter. [Photo: Gen-yu Sasaki]

l The Waterbug Book36 l36

Distinguishing characteristicsNematodes are small pale worms withoutsegments. They are often translucent andcan be curved to the extent that they form a rigid loop. When moving, they will oftenthrash around, coiling and uncoiling veryquickly. They are very small, the largestspecimens reaching 4 mm.

Classification and distributionNematodes are incredibly diverse. The 49genera known from freshwaters in south-eastern Australia are easily outnumbered by the estimates of terrestrial and parasiticnematodes in the same region. They arealso very numerous, a single rotting apple

can hold around 90,000 terrestrialindividuals.

Habitat and ecology Nematodes can survive anywhere there issufficient moisture. Many species areparasitic on other freshwater animals andthe nematodes found in freshwater are acombination of free-living forms andanimals caught between hosts. Nematodescan be predatory, parasitic, or live onbacteria, fungi and plants.

Natural historyNematodes were named from the Greekword nema meaning thread. They are one of

the most widely dispersedanimals on the planet andturn up in polar conditions,at the bottom of marinetrenches and even in hotsprings. It has been said thatif every other animal andplant in the world wasremoved in an instant, wewould still be able to see theiroutlines (and the outlines oftheir internal organs) tracedout in nematodes.

Unsegmented worms: nematodes, nemerteans,horsehair worms, flatworms and crayfish symbionts

This group of animals is united by the simplicity of their shapes. They all have simpledigestive systems, some have a single opening, like the flatworms (including thetemnocephalans), while others like the gordian worms have none at all.

Nematodes are small, pale, unsegmented worms with sharp ends.

Round worms or nematodes (Phylum: Nematoda)

Unsegmented worms l 37

Distinguishing characteristicsGordian worms are usually found as thin,long adults in freshwaters. They can bedarkly coloured and have a wiry body thatmoves purposefully. Their slow movement,length and dark colouring means that theyare sometimes mistaken for wire or twine.Gordian worms are often longer than 50 mm, but seldom thicker than 3 mm.

Classification and distributionThere are six genera of Nematomorpha insouth-eastern Australia, none is endemic.

Horsehair or gordian worms: Gordioidea (Phylum: Nematomorpha)

Nemerteans (Phylum: Nemertea)

Distinguishing characteristicsThe nemerteans are small, pale,unsegmented worms with a distinct snoutand a row of small eyespots. They are rarelylonger than 2.5 mm.

Possible misidentificationsSmall oligochaetes with indistinctsegmentation may appear similar, butexamination under a microscope shouldallow the two to be separated.

Classification and distributionLittle is known about the taxonomy of thisgroup in Australia, but it is possible that themain species found was introduced withaquatic plants.

Habitat and ecologyNemerteans occur in slow-flowingenvironments such as permanent ponds andbackwaters. They hunt for microscopic preyamongst the foliage of aquatic plants.

Natural historyNemerteans have a long, barbed mouth-tube (or proboscis) with which they hunttheir prey. The structure is hollow andattached directly to the stomach and thisallows smaller prey to be swallowed whole,while larger prey are stabbed, poisoned andthen swallowed whole. This armoury,together with silent ciliated movement (see turbellaria) makes the nemerteansformidable predators at a really small scale.

These nemerteans are about 1.5 mm longincluding their long, barbed mouth-tube.

Gordian worms are sometimes mistaken for wireor twine.


Habitat and ecologyAdult gordian worms are free living, in avariety of fast and slow-flowing aquatichabitats. The adult form does not feed, butlarvae and maturing gordian worms areparasites that live inside insect hosts,absorbing their food (the host’s blood)through their skin.

Natural historyAdults may live for several months, but diesoon after mating and laying clusters of eggsin the water. The newly hatched larvae are

inadvertently consumed by aquatic insects.In some tropical species, these primaryhosts must emerge as adults and be eaten by a praying mantis before the worms canproperly mature. In temperate Australia, it is more likely that worms either remain in a single host, or have their hosts eaten bymore common predators such as dragonfliesor beetles. Given the relative sizes of hostand mature parasite, the host eventually diesand the tightly coiled adult worm thenleaves the body and takes to the water tofind a mate.

Distinguishing characteristicsFlatworms are flat, slow moving and thin.They come in a variety of colours, from thedullest greys to jade green. The stream-dwelling species are normally long and dullycoloured, but wetland species can be highlyvariable in both colour and shape. Mostfreshwater species are under 20 mm long.

Possible misidentificationsBecause of their movement, they may appearsimilar to nemerteans, but nemerteans areslender and pale.

Classification and distributionSeven genera of turbellarians occur in

south-eastern Australia. In rivers and lakesthe commonest of these are Cura, Dugesiaand Spathula. The first two are common inlowland systems, while Spathula is found athigher altitudes.

Habitat and ecologyFlatworms are omnivorous animals feedingpartly on prey and partly by scavenging.They occur on the undersides of rocks andwood, in a variety of flow conditions.

Natural historyFlatworms move using short microscopicbristles (cilia) on a path of mucus and thisgives them their unearthly, gliding motion.

Cura sp. can be recognised by its rounded head. Dugesia sp. can be recognised by its arrow-shaped head and large eyes.

Flatworms: turbellarians (Phylum: Platyhelminthes)

Unsegmented worms l 39

Some of the larger flatworms also usemuscular ripples to propel themselvesaround and this allows them to swim in stillwaters such as lakes and billabongs.

Flatworms are also well known for theirability to regenerate from damage. If anindividual is cut in half, it is possible for both parts to form separate individuals.

Flatworms can reproduce sexually andasexually. They lay their eggs in tough,leathery cocoons that are resistant to drying and predation.

Some wetland flatworms (Mesostoma sp.) display a range of body colours from semitransparent tobright green.

Mating flatworms and flatworm cocoons (inset).


Distinguishing characteristicsThe temnocephalans have flat, squat bodieswith two to six tentacles at one end and asuction disc at the other. They are grey,brown or white and are almost always foundon freshwater crayfish. They rarely growlarger than 12 mm.

Classification and distributionSeveral genera and numerous species oftemnocephalans occur in south-easternAustralia. Most genera are endemic, but thesix-tentacled Temnohaswellia is also foundin New Zealand. The genus Temnocephala,once thought to occur in Australia, Asia andSouth America, is now known to berestricted to central and south America.

Habitat and ecologyTemnocephalans occur as externalsymbionts, mainly on freshwater crayfish

but also on the larger species of freshwaterprawn. Some are predators, feeding on smallinvertebrates. Others may browse onmicroflora (bacteria and algae). They do notharm their hosts and can survive withoutthem for prolonged periods. They capturefood using their tentacles.

Natural historyTemnocephaland are usually very mobileanimals, looping leech-like over the surfaceof crayfish. They are, like all flatworms,hermaphrodites. After mating they lay smallleathery cocoons, sometimes on a stalk,which they stick onto the external skelton oftheir host, and from which small immatureworms hatch.

Temnocephalans attached to the claw of acrayfish and (inset) showing their suction discand tentacles.

Crayfish symbionts: temnocephalans(Phylum: Platyhelminthes)

Freshwater leeches l 41

Since medieval times leeches have beenused for medicinal purposes. The mostfamous medicinal leech is Hirudomedicinalis, a species of bloodsuckingaquatic leech from Europe. In Australia and New Zealand, the native ‘tiger leech’(Richardsonianus) is used in microsurgery,plastic surgery and for treatment ofthrombosis. Apart from being excellentblood pumps, leeches release substancessuch as anticoagulants that prevent bloodclotting and assist in surgery. A leech’s bite ispractically harmless though some peoplecan develop an allergic reaction or asecondary bacterial infection.

Distinguishing characteristicsLeeches have a body made up of 32segments and this number is constant for allspecies. They have a smaller anterior suckerand a larger cup-like posterior one. Someleeches like glossiphoniids crawl by movingthe anterior sucker forward, attaching it,and drawing up the posterior sucker whilehirudinids and erpobdellids can swim byrapidly undulating their body. Adult leechesrange from 7 mm to about 20 cm in length.Their length is difficult to measure sinceleeches constantly contract and stretch theirbodies. Often the body form is elongatedand flat but some are cylindrical. This can vary depending on the stage of themovement and whether the leech is starved

or has just had a meal. During swimming,the bodies of the Hirudinidae andErpobdellidae become flattened to form akind of a keel that makes them resembleminiature eels. Leeches have one or morepairs of eyes. Their bodies are usually blackand brown and can be patterned withstripes and spots.

To many people leeches are not very charismatic animals due to their annoyinghabit of sucking blood from people’s legs. However, freshwater leeches arefascinating to study as they possess powerful sensory organs and can displaycomplex parental behaviour.

Freshwater leeches (Phylum: Annelida, Class: Hirudinea)

An erpobdellid leech can easily stretch to threetimes its normal size.


It is possible to distinguish three commonfamilies in south-eastern Australia:glossiphoniids have a flattened or pear-shaped body, hirudinids are distinctlystriped and erpobdellids are thin andelongated.

Possible misidentificationsLeeches are difficult to confuse with otherworms, though smaller specimens mightresemble turbellarian flatworms. Leechescan easily be distinguished by theirsegmented bodies and the presence ofsuckers. Leeches can also be confused witholigochaet worms (see pages 44–45).

Classification and distributionFive families of freshwater leeches are foundin Australia: Glossiphoniidae,Ozobranchidae, Hirudinidae (formerlyRichardsonianidae), Ornithobdellidae andErpobdellidae. Of these, Glossiphoniidae ismost common in south-eastern Australiafollowed by the Hirudinidae such as the‘tiger leech’ (Richardsonianus) andErpobdellidae. Ornithobdellids are restrictedto tropical Queensland and examples of theOzobranchidae are quite rare.

Habitat and ecology Leeches are predators. Most of them useambush tactics while some genera, such asMotobdella (Family: Erpobdellidae), activelyseek their prey. Many leeches use theirproboscis to suck the insides from worms,molluscs and midge larvae, just like avacuum cleaner. Others use their sharp jawsto feed on the blood of frogs, turtles, waterbirds, cattle and some inquisitive biologists.Blood-sucking leeches are able to detectminor water disturbances so an easy way tocatch them is to dangle something (evenyour hand if you are brave) in the water.Leeches occur in a wide range of freshwaterhabitats.

A glossiphoniid leech showing the typicallyarched body, mid-step.

A glossiphoniid leech showing eye spots.

A glossiphoniid leech with a brood of young onits ventral surface.

Freshwater leeches l 43

Glossiphoniids prefer running waters whilethe hirudinids and erpobdellids are morelikely to occur in stagnant and slow movingwaters. Some groups can tolerate lowoxygen concentrations and high levels ofwater pollution. To cope with low oxygenconcentrations leeches often ventilate theirbody surface by performing swimmingmovements while being attached to somehard surface. Most leeches are active andhunt at night.

Natural historyLeeches are hermaphroditic. They carrymale and female sexual organs and caneasily swap between reproductive roles.Leeches playing the role of a male can

sometimes display courtship behaviour.The young leeches hatch from eggs asminiature copies of adults. Parentalbehaviour of leeches ranges from simplydropping their eggs to extreme and tendercare and many glossiphoniid leeches carrytheir young underneath their bodies forsome time before releasing them into theoutside world. F. Goveditch, an expert inleeches, reported that some leeches (e.g.Glossiphonia) even transfer nutrients acrossthe body wall to their developing young.He also observed that the reproductivestrategy of some male Glossiphoniid leechesis to try to impregnate as many femaleleeches as possible before switching genderand trying to get pregnant themselves.

Hirudinid leeches (Richardsonianus sp.) aregood swimmers and have distinctive stripes.


Distinguishing characteristicsFreshwater oligochaet worms can be red,tan, brown, cream or black in colour andsome of them sport noticeable externalfeatures. For example, some species of Naishave pigmented eye spots that make themlook like sock puppets, while Branchiurasowerbyi has dorsal and lateral gills. Speciesof Dero have elongate growths at theposterior tip of their bodies. Theseprotuberances act as gills increasing bodysurface area and helping the worm to trapmore oxygen. All of the aquatic wormscharacteristically move by stretching andpulling their bodies. The blackworm,Lumbriculus variegatus, is often sold as fishfood in aquarium shops and is one of themore common and widespread species.

Possible misidentificationsSmall oligochaetes can be confused withleeches. The main feature that helps toseparate these groups is the presence of asucker on leeches and the leech’s ability tolift one end of its body off the ground. Thetexture of leeches (when they are dead) ismuch harder. Oligochaetes have a variablenumber of segments while leeches alwayshave 32 segments.

Classification and distributionThe class Oligochaeta includes about 3500species of earthworms and freshwaterworms globally, with at least 90 species of

freshwater worms recorded in Australia.The class Oligochaeta is usually divided intotwo superorders: the larger worms orMegadrili (from the Greek: mega = large,drilos = penis or worm), which is closelyrelated to and resemble the commonearthworms, and the much smaller wormsof the Microdrili (Greek for ‘small worms’).

The majority of worms found in freshwaterbelong to the Microdrili, many of them areonly several millimetres long. Some speciessuch as Lumbriculus variegatus and Aulorilussp. are found worldwide while other genera(e.g. Antipodrilus) are restricted to thesouthern hemisphere. The common familiesin Australia are Lumbriculidae,Enchytraeidae, Naididae, Tubificidae,Phreodrilidae and Haplotaxidae.

Habitat and ecologyMost oligochaetes live in soft sediment richin organic matter, and the common name,‘sludge worms’, for the tubificids clearlydescribes their habitat. Bacteria and algaethat abound in sludge and fine sedimentsare the main source of food for worms, butsome species of Chaetogaster (from thefamily Naididae) are carnivorous. Theirlarge mouth opening and relatively shortbody make them look like microscopicliving macaroni. Another naidid worm,Chaetogaster limnaei, is a symbiont offreshwater snails and clams. It lives in theirmantle cavity.

Segmented worms (Phylum: Annelida, Class: Oligochaeta)

Freshwater oligochaet worms are plain-looking animals. They can look like ordinaryearthworms but more often they are much thinner and shorter. They are allsegmented, and if you use a microscope you can observe short bristles and hairs oneach segment.

Segmented worms l 45

Environmental significanceOligochaetes are probably the onlyfreshwater invertebrates that can occur intotally degraded habitats such as sewageoutlets and degraded urban streams. Theyseem to survive in streams with nutrientand pollution levels many times greaterthan the accepted level. Some worms canlive in waters with an oxygen concentrationclose to zero.

Oligochaetes are so tolerant they often serveas an indicator of poor health in aquatichabitats. While worms are one of the mosttolerant macroinvertebrates, they are notrestricted to polluted waters and also occurin pristine habitats.

Natural historyMost freshwater worms are hermaphrodites,possessing both male and femalereproductive organs. They reproducesexually or by fission. A specialised buddingsegment at the tail end of the worm canstart growing to give rise to a new worm.The newly formed worm either breaks offfrom its parent or continues buddingforming another worm whilst still attachedto the parent. These newly formed wormsare called zooids. When reproducingsexually, oligochaetes produce a cocoon inwhich they deposit fertilised eggs. When theyoung worms emerge from the cocoon theylook like miniature adult worms.

The black worm, Lumbriculus variegatus, isvery common and is often used as food foraquarium fish.

Branchiura sowerbyi, a tubificid worm, hasconspicuous finger-like gills along the posteriorhalf of its abdomen.

Tubificid worms burrow head first into the mud. Pristina sp. has a characteristic anteriorproboscis.


Freshwater snails, mussels and clams (Phylum: Mollusca, Classes: Bivalvia and Gastropoda)

Chitons, clams, cuttlefish, mussels, octopus, squid, snails, and slugs are all molluscs,but only two classes, the bivalves and the gastropods, have successfully left the seaand invaded the land and its freshwaters.

anterior adductormuscles

posterioradductormuscles

hingestomach

footshell

gill\ciliatedgroove

BIVALVE

Dextral (openingon right)

spire

body/whorl Sinistral (openingon left)

eye

palp

gills or lungs

stomach

mantle

mantle cavityGASTROPOD

mouthradula radula sack

operculum

albumen/shellgland

SHELL TYPES

Freshwater snails, mussels and clams l 47

Distinguishing characteristics Mussels and clams (the bivalves) are usuallyclosed when we find them and the fleshybody within the paired valves is rarely seen.The shells vary a lot in thickness and size,some of the hyriids are longer than 10 cmwhen fully grown, while the sphaeriidsnever exceed 10 mm. If they are left alonelong enough, most bivalves reveal a strong,fleshy foot, with which they can burrow intofiner sediments. Bivalves are ratherdescriptively named: bi is the Greek for twoand valva were originally the individual‘leaves’ of a folding door.

The freshwater snails (the gastropods) of temperate Australia are all soft-bodiedanimals that carry a hard, often coiled shellupon their backs, into which they canwithdraw when threatened. Their headscarry a pair of eye stalks and a pair oftentacles, though one or both of these areless obvious in some freshwater species.Sometimes the retreating animals will havea door or ‘operculum’, which blocks theentrance to the shell once the animal isinside. The name gastropod is from theGreek, meaning stomach (gastro-) footed (-poda), referring to the way the animal’sstomach is so close to its foot.

The origin of freshwater molluscsBoth bivalves and gastropods are primarilymarine organisms—they evolved in the sea.Freshwater bivalves are likely to be descendedfrom a string of successive species thatworked their way up through the estuariesinto the freshwater where we find themtoday. Each step left a new suite of species,tolerant of slightly lower salinities.

Some gastropods may have found their wayinto freshwaters the same way, but as theymoved upstream, they followed two distinctevolutionary paths. One group made thetransition without greatly altering its shape:these were the operculates, named after the

operculum or door that closes their shells.The other group simplified its gills anddeveloped an empty chamber or lung tobreathe with. This second group gave rise to the ancestors of the land snails and alsothe ancestors of the pulmonate, or ‘lungbearing’, freshwater gastropods. This groupincludes the Lymnaeidae, Planorbidae,Physidae, Ancylidae and possibly theGlacidorbidae. Interestingly, many of thesesnails have evolved further and are onceagain equipped with gills. However, some of the Lymnaeidae and Physidae retain the‘lung’ and this has allowed them to carrytheir own air supply in particularly oxygen-poor environments. Sometimes these snailscan be observed just under the watersurface breaching the surface tension andrefilling their air supply.

The freshwater mussel, Velesunio sp. showingsiphons (right), and a muscular foot (left).

The freshwater snail Glyptophysa sp. showingpalps, foot and shell. Its eye is at the base of itstentacle, rather than at the tip.


ClassificationThere are 7 genera of bivalves from 3 familiesand about 34 genera of gastropods from 10 families that occur in the non-marinewaters of temperate Australia. This makesthe freshwater mollusc fauna quite diverseand if present trends in gastropod taxonomycontinue, there will doubtless be many morespecies described.

Environmental significanceThe freshwater molluscs are such a diversegroup that it is impossible to make a generalcomment on their sensitivity to pollutants.However, introduced species, such asPotamopyrgus antipodarum and Physa acuta,do tend to thrive under degraded conditionsand can be seen as indicators of poor waterquality and particularly nutrient enrichment.

1 animals snail, or limpet-like (class Gastropoda) with a single whole shell . . . . . . . . . 41 animals clam, or mussel-like (class Bivalvia) with two halves of shell . . . . . . . . . . . . . 2

2(1) shell halves large, thick, not symmetrical, often with dark coloured outer layer that flakes off near the hinge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hyriidae (p. 50)

2 shell halves small, thin relatively symmetrical and round . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3(2) shell very small (<6 mm), thin and almost transparent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sphaeriidae (or possibly immature Hyriidae/Corbiculidae)(p. 51)

3 shell larger than 6 mm, opaque, and sometimes with concentric ridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Corbiculidae (p. 49)

4(1) animal with operculum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 animal without operculum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5(4) shell coiled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 shell simple, limpet-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

6(5) shell can be larger than 5 mm, adorned with remnant spiral, and ribs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Planorbidae (genus Ancylastrum) (p. 56)

6 shell smaller than 5 mm, simple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ancylidae (p. 51)

7(5) shell sinistral (opening on left), tentacles slender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Planorbidae/Physidae (p. 56)

7 shell dextral (opening on right), tentacles squat and triangular . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lymnaeidae (p. 54)

8(4) shell small, coiled but flat (without spire) . . . . . . . . . . . . . . . . . . . . . Glacidorbidae (p. 53)8 shell coiled with spire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

9(8) shell sculptured with spiral ridges, grooves and longitudinal ribs, can be as large as 25 mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thiaridae (p. 58)

9 shell without sculpturing, or with less complicated sculpturing . . . . . . . . . . . . . . . . . . 10

10(9) animal found in salt, or coastal lakes, high spired . . . . . . . . . . Pomatiopsidae (p. 57)10 animal found in freshwater, or at the estuarine end of rivers . . . . . . . . . . . . . . . . . . . . 11

11(10) operculum with spiral pattern, typically smaller than 10 mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrobiidae (p. 53)

11 operculum patterned with concentric rings, can be larger than 10 mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bithyniidae/Viviparidae (p. 52)

Key to the families of Mollusca (after Smith 1996)


Distinguishing characteristicsThe corbiculids are medium-sized bivalveswith opaque, cream–pink/purple colouredshells. The shells are slightly asymmetrical,sculptured with concentric ridges, andmeasure between 10 and 25 mm long.

Possible misidentificationsSmall specimens can resemble theSphaeriidae but these generally have

comparatively transparent shells. There arelarger genera than Corbicula in northernAustralia, but anything larger than 25 mmin south-eastern Australia is likely to be anunderdeveloped hyriid mussel such asVelesunio sp. or Hyridella sp.

Radulas and the ciliated grooveFreshwater gastropods have highly muscularmouthparts that include a file-like structurecalled a radula. The radula scrapes foodwith rows of tiny sharp teeth, each rowremoving another chunk of food.

A backward and forward motion allows thefood to be rasped and then ratchetedtowards the back of the mouth cavity. Theradula wears at one end but is replaced at itsorigin, the radula sac.

Bivalves have a similarly novel method offeeding. They feed from the water column,pumping water in through a siphon. Thewater is then sieved and food and rubbishare sorted as they travel towards the mouthalong a structure known as the ciliatedgroove. Cilia are small hairs that can moveand these push and sort the detritus. Waterand rubbish that has been sorted are then

exhaled by the bivalve through a secondsiphon, while food particles are wrapped inmucus and travel to the mouth and digestivesystem. The water pumped through the bodyalso passes over the gills bringing a constantsupply of fresh, oxygen-rich water.

The radula of a hydrobiid snail helps it scrapealgae and bacteria from hard surfaces.

Little basket shells (Class: Bivalvia, Family: Corbiculidae)

Corbicula sp. showing its ridged shell. Littlebasket shells can be found in large numbers insandy sections of some rivers.


Distinguishing characteristicsMussels from the family Hyriidaesuperficially resemble the well-knownmarine mussels. Their shells are thick andcovered in a dark, flaky, outside layer, whichcan wear off near the hinge. Some are quiteoblong-shaped, while others appear quitesymmetrical and rounded. They vary insize, between 40 and 120 mm.

Possible misidentificationsImmature specimens can be confused withthe Corbiculidae. The hyriids are usuallymore darkly pigmented.

Classification and distributionFour genera and 11 species of Hyriidaeoccur in south-eastern Australia.

Cucumerunio is from New South Wales.Alathyria, Velesunio and Hyridella all haverepresentatives in patches throughoutsouth-eastern Australia.

Habitat and ecologyThe hyriids live in lowland river systems.They burrow in the finer sediments such assand and mud, using a muscular foot todrag the shell below the surface. Freshwatermussels also commonly occur in irrigationcanals and connected farm dams. Whenfilter feeding, the hind edge of the shellremains exposed, allowing a pair of siphonsto pump water from the passing flow intothe shell, where the food and rubbish aresorted from it.

Natural historyThe hyriids spend their early life as a small,simply formed parasite on the gills of nativefish. The young attach themselves to the gilltissues of fish with hooks and remain thereuntil they have developed. The youngmussels drop free from their host with a fullydeveloped siphon system and take to thesofter sediments alongside the adult forms.

Fully grown freshwater mussels arerenowned for being able to clear a bucket ofmuddy water overnight and are also able totolerate prolonged dry spells, buryingthemselves in the mud and sealing theirshells tight until water returns.

Classification and distributionOne genus Corbicula (previouslyCorbiculina) is found in mainland Australiabut not Tasmania.

Habitat and ecologyCorbiculids live buried in the sands ofshallow fast moving streams. They feed byfiltering food particles from the water.

Natural historyCorbiculids are sometimes found in largeenough numbers to block irrigationequipment. The young develop brieflywithin the protective shell of the parent,before being released into flowing water inlarge numbers. They then aggregate insuitable sections of river, or irrigationequipment.

Velesunio sp. lives partially buried in finesediments. Its shell can be found in the mudalongside irrigation canals in central Victoria.

Freshwater mussels (Class: Bivalvia, Family: Hyriidae)


Distinguishing characteristicsAncylids are small gastropods (<4 mm)with simple shells that lack coiling. Theshells also lack sculpturing or ribs, thoughthey can sometimes sport a healthy growthof fine algae. The animal is rarely visiblebeneath its shell.

Possible misidentificationsThe ancylids are very distinctive and canonly really be confused with the planorbidgastropods from the genus Ancylastrum.These animals differ by having distinct ribsupon their shells and the remnants of acoiled shell. They are also only found inlakes on the central plateau of Tasmania.

Classification and distributionOne genus with two species is recordedfrom south-eastern Australia. Ferrissiatasmanica has a darkly pigmented layerimmediately beneath the shell (the mantle)and is slightly deeper in profile thanFerrissia petterdi.

Habitat and ecologyFreshwater limpets occur in streams,ponds and lakes, on a variety of surfaces.They can handle a variety of flow speedsand will occur on rocky substrates, woodydebris and amongst macrophytes. Theygraze upon the periphyton available on allthese surfaces.

Pea shells (Class: Bivalvia, Family: Sphaeriidae)

Distinguishing characteristicsThe sphaeriids are the smallest of thefreshwater bivalves measuring a maximumof about 10 mm across. The shells aretranslucent and very thin.

Possible misidentificationsSee Corbiculidae and Hyriidae.

Classification and distributionTwo genera, Sphaerium, usually 5 to 10 mmacross, and Pisidium, a smaller genus, occuracross south-eastern Australia.

Habitat and ecologyPea shells occur in rivers, creeks or ponds,where there is sufficient fine sediment for

them to burrow in. They are filter feeders.

The shells of the minute freshwater clam,Pisidium sp., are translucent.

Freshwater limpets (Class: Gastropoda, Family: Ancylidae)

The freshwater limpet Ferrissia petterdi with anoddly developed shell.

Natural historyFreshwater limpets in other countries haveslightly different shells depending on thespeed of the water they occur in—in fastflow they tend to have lower sleeker-shapedshells. If this is true for Australian species,we would expect Ferrissia petterdi to be astream species rather than a pond or lakespecies. Ancylids in other parts of the worldlive for about a year and are hermaph-roditic, but cannot fertilise themselves assperm and ova are kept separately withintheir bodies.


Distinguishing characteristicsThe snails from both these families havesquat, dextrally coiled shells (opening to theright) and an operculum patterned withconcentric rings. They are also bothanonymously cream–brown coloured. Thebithyniids are slightly smaller when fullygrown, reaching a maximum of 12 mm,while the viviparids can be twice this size.The two families also differ in that themiddle concentric ring on the operculum ofthe Viviparidae is slightly off-centre.

Possible misidentificationsSome of the Hydrobiidae may appearsimilar, but these have a spiral pattern on

their operculum, rather than a set ofconcentric rings.

Classification and distributionOne native genus (Notopala) with about fivespecies represents the Viviparidae in south-eastern Australia. An introduced viviparidaquarium snail (Bellamya heudeiguangdungensis) can also be found in theSydney region. One genus of the Bithyniidaeis found in south-eastern Australia: Bithynia(formerly Gabbia) with four species. Thesetwo families are currently being revised, soan increase in species numbers is likely.

Habitat and ecologyThe Australian forms of both these familiesoccur in inland systems, such as theMurray-Darling and the Lake Eyre Basins.Both are grazers of periphyton and occur inslow moving or still waters. Bithyniids aretolerant of mild salinities.

Natural historyThe viviparids are named after the fact thatthe young mature inside eggs while stillinside the parent and the parent then givesbirth to live young. This is unusual amongsnails, which normally lay eggs externallyand inevitably lose some to egg predators.

The shell of Ferrissia tasmanica can be coveredin algae.

These examples of Notopala were found in alowland river. [photo: K. Jerie]

Class: Gastropoda, Families: Bithyniidae and Viviparidae


Live bearing increases the number of youngthat survive, as they are released into theoutside world as mobile individuals. Theviviparid snail Notopala hanleyi was thoughtto have become extinct in the lower Murraysystem sometime in the 1970s, until a large

population was discovered blockingirrigation pipes in the area. The animal’slocal extinction is thought to be due to itsdependence on food sources that havebecome drastically altered by flowregulation.

Class: Gastropoda, Family: Glacidorbidae

Distinguishing characteristicsThe glacidorbids are small, flat, coiled snailsusually with yellow–brown shells. They havean operculum, though this may be difficultto see as the entire animal rarely exceeds 6 mm in length.

Possible misidentificationsSome of the planorbids are flattened in asimilar way to the glacidorbids, but they arelarger and do not have an operculum.

Classification and distributionOnce lumped as a single genus within theHydrobiidae, this family now has fourgenera: Glacidorbis, which occursthroughout south-eastern Australia; andStriadorbis, Benthodorbis and Tasmodorbis,which occur in Tasmania.

Habitat and ecologyGlacidorbids have been found in streams inalpine areas in Victoria and New SouthWales, swamps in Victoria and inmountainous areas and at the bottom oflakes in Tasmania. They are thought to becarnivorous.

The glacidorbid snails have a simply coiled shellthat is often only 2 or 3 mm across.

Distinguishing characteristicsThis diverse group of small snails coverssquat, rounded animals as well as relativelyhigh spired shells. The commoner speciestend to be small, dark coloured, dextrallycoiled snails. Most species are smaller than 5 mm.

Possible misidentificationsSnails from the family Pomatiopsidae arevery similar, but although some of theHydrobiidae occur in estuarine locations,none have been recorded from the salinelakes where pomatiopsids are found.

Class: Gastropoda, Family: Hydrobiidae

The genus Beddomeia is very diverse. Differentrivers will have different species, even if they arein the same catchment.


Classification and distributionHydrobiids occur throughout south-easternAustralia. They are represented by around12 genera and are prone to extreme local

speciation. In contrast, the introducedhydrobiid snail Potamopyrgus antipodarumis now almost cosmopolitan. It has invadedboth Europe and Australia from itshomeland of New Zealand.

Habitat and ecologyThe hydrobiid snails occupy a diverse rangeof aquatic habitats and it would not besurprising if they turned out to be just asecologically diverse, but as yet very littlework has been done on their biology.Like other groups, they can occur in hugequantities. The introduced snailPotamopyrgus antipodarum thrives innutrient-rich urban and rural streams.

Natural historyThe hydrobiids reproduce sexually.The females lay small bundles of eggs,sometimes in mucus and sand grain cases.Many live for longer than a year and havevery restricted habitat tolerances.

The New Zealand hydrobiid snail, Potamopyrgusantipodarum, showing its snout and theoperculum that closes the shell.

Pond snails and liver fluke snails (Class: Gastropoda, Family: Lymnaeidae)

Distinguishing characteristicsThe family Lymnaeidae is distinguished bythin, dextrally coiled shells, which have awide opening and no operculum. The shellsare broad, with the first loop or body whorlmuch larger than subsequent turns.Sculpture, if present, is dominated by finespiral lines. The live animals havedistinctively short, triangular tentacles,with eyes at their bases. Most lymnaeids are smaller than 20 mm.

Possible misidentificationsSome members of the Physidae/Planorbidaeare similar looking and occur in the samehabitats, but they are coiled in the oppositedirection (sinistral). Land snails from the

Austropeplea lessoni can be found amongstweeds in ponds and billabongs. Its broadtriangular tentacles are quite distinctive.


family Succineidae are often found near thewater’s edge and can sometimes fall in.They have similar shells but differ from theLymnaeidae by having cylindrical tentacleswith eyes at their tips rather than their base,and more constricted shells at the start andfinish of each whorl.

Classification and distributionSix species, from four genera are found insouth-eastern Australia. The native genusAustropeplea has two species, Kutikina hasone, and there are a further three speciesintroduced from Europe and NorthAmerica. The European snails are from the genus Lymnaea and the North Americansnails from Pseudosuccinea. Kutikina is asmall snail restricted to sections of theFranklin River in south-west Tasmania.

Habitat and ecologyLymnaeids are typically found in slow-flowing or still waters, grazing algae fromhard surfaces. The coarse grain of theirradula teeth reflects their diet ofcomparatively large filamentous algae.Most other snails feed on the finer algal andbacterial parts of the periphyton. Lymnaeidscan survive in water with very low oxygencontent by floating to the surface and fillingtheir ‘lung’ with air.

Natural historyWith most lymnaeids, eggs are fertilised inboth partners during sexual reproductionand these are then laid in clusters, fromwhich miniature snails eventually emerge.Most lymnaeids are short-lived but capableof self-fertilisation.

Nasty free-loadersThe native lymnaeid Austropepleatomentosa and the introduced speciesPseudosuccinea columella are bothintermediate hosts for the sheep liver flukeFasciola hepatica. Ian Clunies Ross, thefamous parasitologist, unravelled thecomplicated lifecycle of these parasites inthe 1930s. Sheep liver flukes start their lifecycle as eggs, passed in faecal matter byinfected animals. These eggs enter a pond,dam or small stream and once they havehatched find their first host: a lymnaeidsnail. Once inside the snail, the liver flukelarva begins to mature in various organs ofthe unfortunate snail, until it can reproduceasexually. It then infests the snail with manygenetically identical versions of itself.Eventually these second-stage larvae leavethe snail and crawl from the pond or streamside, into the surrounding vegetation wherethey attach themselves to grass near thewater’s edge, waiting to be eaten by theirfinal hosts. These hosts can include nativeanimals such as kangaroos and wallabies,

but were originally sheep. Once insidesheep, the fluke larvae travel from theintestine into the abdominal cavity, wherethey infest the liver and bile ducts. After amonth or two the flukes mature, the adultform is from 15–40 mm in length and cando quite a lot of damage to a mammal’sinternal organs. Eggs from the adult flukesfind their way into faecal matter and arereleased into or near water once again. Incomparison, the snail’s life is quite dull.

Austropeplea tomentosa is thought to be anintermediate host of the sheep liver fluke.


Distinguishing characteristicsThe Planorbidae is a diverse family withshell shapes ranging from flat to high spiredand with varying degrees of shell sculpture.Planorbids lack an operculum, and arealways sinistrally coiled (opening to theleft). The physids are represented by a singleintroduced species Physa acuta, whichshares all these characters, but also hasfinger-like processes under the edge of itsshell and a mottled mantle that can be seenthrough its translucent shell.

Possible misidentificationsThe flat-shaped genera superficially resemblemembers of the Glacidorbidae, but differ bybeing larger and lacking an operculum. The

genus Ancylastrum shares parts of its name,as well as its form, with the Ancylidae. How-ever, it is larger than any of the Ancylidae andhas ribs and a remnant of a spiral at its tip.

Classification and distributionEight genera of the Planorbidae are foundin south-eastern Australia. These are:Planorbarius, Isidorella, Glyptophysa andBayardella; the flat-shaped genera Helicorbis,Pygmanisus and Gyraulus, and the limpet-like Ancylastrum. The physids arerepresented by a single introduced species,Physa acuta.

Habitat and ecologyThe planorbids inhabit a diverse range ofaquatic habitats, but most are from slow-moving waters. The physids are similarlydistributed.

Natural historyBoth the Planorbidae and Physidae arehermaphrodites—they are capable of self-fertilisation and reproduce at least once ayear.

The giant limpet Ancylastrum is extremelyrare. It used to occur throughout lakes onthe central plateau of Tasmania, but themost recent records of it are from trout gut-contents in the 1980s.

Class: Gastropoda, Family: Physidae/Planorbidae

Gyraulus tasmanicus is one of the flat planorbids that gives the family its name.

The introduced snail Physa acuta has a mottledmantle that is usually visible through the shell.


Glyptophysa is a very diverse genus, with a range of shell ornamentation. The commonest speciesis Glyptophysa gibbosa (bottom right).

Distinguishing characteristicsThe shells of the pomatiopsid snails arepale-coloured and chalky. They are dextrallycoiled and smaller than 8 mm high.

Possible misidentificationsSnails from the family Hydrobiidae are verysimilar, but they do not occur in the salinelakes where pomatiopsids are found.

Classification and distributionTwo species of Coxiella occur in Victoria,Tasmania and South Australia. The familydoes not occur in other states of south-eastern Australia.

Habitat and ecologyThe pomatiopsids live at the edge of saltlakes in inland south-eastern Australia.

Salt lake snails (Class: Gastropoda, Family: Pomatiopsidae)

Coxiella is easily recognised by its typicallyshortened spire.


Distinguishing characteristicsThe thiarids are one of the more ornatelysculptured freshwater gastropods of south-eastern Australia. The commonest genus isadorned with a combination of ridges,grooves and raised longitudinal ribs, whichmake it look more like something found atthe beach. Shells are dextrally coiled, highspired with a thick operculum and reach 25 mm in length.

Possible misidentificationsWhile some of the Planorbidae can havequite ornate shells, they are rarely as large,lack an operculum and have sinistral coils.

Classification and distributionOne genus, Thiara (formerly Plotiopsis) isquite common throughout the Murray-Darling and other inland basins.

Habitat and ecologyThe thiarids of south-eastern Australia areperiphyton grazers in flowing water. Theypersist in soft sediments and can withstandperiodic drought.

Natural historyThe thiarids are a very diverse groupglobally, with most of their diversity centredin the tropics. They are most notable fortheir tendency for parthenogeneticreproduction, which enables new colonies ofthe animal to arise from an individual.

Sculptured snails (Class: Gastropoda, Family: Thiaridae)

Thiarid snails are the most heavily ornamented freshwater snails in south-eastern Australia.

Freshwater mites and spiders l 59

Distinguishing characteristicsWater mites are a very variable group butall have simple rounded bodies with eightlegs. Their mouthparts include a pair ofpalps and a structure for piercing theirprey called a rostrum. Some of them haveswimming hairs on their legs. Some arehard bodied, while others are soft.Parasitic, juvenile forms often have six legs.Free-living adults of the larger species ofmite can grow to around 5 mm.

Classification and distributionTwenty-five families of mite occur in thefreshwaters of temperate Australia. Manyspecies are endemic, though there are also anumber of cosmopolitan species. The mitesfound in freshwater environments tend to bewidespread but patchy in their distributions.

Habitat and ecologyAquatic mites spend varying amounts oftheir youth out of the water. This is becausethey are attached to aquatic insects asparasites. Once they have matured, mitesbecome predatory, using their beak-likerostrum to pierce their victims. Preyincludes early instar insects andmicrocrustaceans. Mites occur in allfreshwater habitats, but are more plentiful,and diverse in slower flowing waters.

Natural historySome of the more obvious freshwater mitesin freshwaters are large, round and brightred. Unfortunately, these are not all thesame and ‘big red mites’ come from a wholerange of families such as the Eylaidae,Hydrachnidae and the Limnocharidae.

Freshwater mites and spiders (Class: Arachnida)

Arachnids have eight legs and highly fused body segments. Instead of having a head,prothorax, mesothorax, metathorax and abdomen, these have been simplified to acephalothorax and an abdomen in spiders and a single body segment in mites.

Freshwater mites (Order: Acarina)

Many of the freshwater mites propel themselves through the water with their hair covered legs. This movement appears frantic, and sometimes random.


In many cases this red colouration iscombined with pores in the skin thatsecrete a distasteful substance. Largerpredators such as fish soon learn toassociate the bright red with an unpleasanttaste and leave the mites alone. Some mitescheat and use the protective red colourwithout developing the toxic defences.

Non-red mites are by no means totallydefenceless. Many have hard plates coveredwith spines and blades which offer asimilarly strong disincentive to largerpredators.

The ‘big red mites’ are from a variety of differentfamilies. Most of the characters needed toidentify them accurately require a microscope.

Distinguishing characteristicsThese spiders are robust, fast-movinghunters. They have mottled colouringsincluding grey, brown and green, sometimeswith pale stripes. They are covered in finehairs, giving them a velvety appearance. Thepisaurids build a nursery web for their eggsand spiderlings and the lycosids sometimeslive in silk-lined tunnels. Neither has a fixedweb. Members of both the Pisauridae andLycosidae occur in a range of sizes, withbody lengths from 10–20 mm. Total lengthwith legs can exceed 120 mm.

Possible misidentificationsThe Pisauridae and the Lycosidae are veryeasy to confuse. The pisaurids generallyhave thinner legs and more mottledcolourings. They are the more common ofthe spiders that hunt on water. Lycosids lookslightly more robust and have their eyesarranged in three rows with the posteriorpair considerably enlarged.

Classification and distributionThe Pisauridae is represented in south-eastern Australia by a single genusDolomedes, while the Lycosidae includesseveral genera, which are infrequently foundaround freshwater.

Habitat and ecologyBoth the Pisauridae and the Lycosidae hunton or near the water surface, in spots wherethe water provides a ripple-free surface.

Natural historyThese spiders wait beside the water withseveral legs touching the water surface,using it a bit like a large wet web. Strugglinginsects (or sometimes fish or tadpoles) sendripples through the water, which alert the

Nursery web spiders, fishing spiders, swamp spiders (Family: Pisauridae) and wolf spiders (Family: Lycosidae)

Fishing spiders can either have prominentstripes, or a mottled green pattern.

Freshwater mites and spiders l 61

spiders to their prey. Fishing spiders(Pisauridae) are able to hunt actively belowthe surface of the water as well. The densehairs that give them their velvety appearanceare waterproof and trap air between them,stopping the spider from becomingwaterlogged. This sheet of air bubbles makesthe spider very buoyant however, and if itlooses its grip, it will shoot to the surface,instantly parting the surface tension.

Fishing spiders can stay submerged for upto an hour or so and this can help themevade larger predators such as birds.Although their venom is harmless tohumans, fishing spiders can be quiteaggressive and can deliver a painful bitesimply due to the size of their fangs.

Nursery webs, built by fishing spiders, cansometimes be found amongst the vegetationnear freshwater. They are usually sheets of

web, forming tent-like structures, anchoredto the surrounding rocks and vegetation.These structures are only ever built to housethe egg sac and spiderlings. In contrast, wolfspiders often carry their young with them asa seething mass of tiny spiders on themother’s back.

A fishing spider (Dolomedes sp.) uses the water surface like a giant web and will skate out and feedon anything small that causes a ripple.

Female wolf spiders carry their egg sacs withthem, while they hunt.


Distinguishing characteristicsLong jawed spiders are distinctly long-legged,web-spinning spiders, found along the edgesof most water bodies. Their abdomens arelong and their jaws are very large. They spintheir webs horizontally across or near waterand when disturbed they leave their websand lie along the reeds or branches that theweb is attached to. Their mottled colouringsand stick-like shape make them difficult tospot once they are still. Mature femalespiders are slightly larger than males with a body length from 15–20 mm. Includinglegs, their total length is around 60 mm.

Classification and distributionThe Tetragnathidae (formerly part of theArgiopidae) is quite a diverse family, but onlythe genus Tetragnatha is consistently foundnear water. They occur throughouttemperate Australia, with around 10 differentspecies spread through different regions.

Habitat and ecologyLong jawed spiders are predators. Theyoccur around all types of water bodies. It isthought that their horizontally slung netsare designed to snare aquatic insects and

the diverse range of true flies (Diptera)associated with the water margins.

Natural historyIn many types of spider, the female eats themale after they have mated (and sometimesbefore). Long jawed spiders are one of thefew groups where the male actually escapes.The male holds the female’s fangs apart andkeeps them at a safe distance with his own.This is thought to be the main use for theiroverly large jaws. Males transfer sperm tothe females with a small leg-like appendagecalled a palp, which is located behind thejaws. Just to be safe, these spiders have alsodeveloped very long male palps.

Long jawed spiders (Family: Tetragnathidae)

A female long jawed spider.

A long jawed spider makes a meal of a damselfly. It feeds on the winged adults of aquatic insects.

Microcrustaceans l 63

Microcrustaceans: water fleas, copepods,clam shrimp and seed shrimp

Microcrustaceans are a large group of very small animals that often turn up in samples from rivers, ponds and wetlands. Because they are so small, we only ever see their largest representatives.

Water fleas (Order: Cladocera)

Distinguishing characteristicsThe cladocerans are called water fleasbecause of their jerky movement and thebeak-like shape of their heads. They have asimple carapace that covers the animal’sbody and is extended around the head.Sometimes this is extended further to formspines on either the head or the tail. Theantennae are often enlarged and branchedto help push the animal through the water.The eggs of mature females can sometimesbe seen through the side of the carapace,lined up along the back, or in bundles onthe sides.

Microcrustaceans are common in still waterhabitats such as lakes and wetlands and canbe a useful indicator of water quality. Theyare found in sediments, as well as living freein open water. They are best collected witha very fine mesh sieve (<0.25 mm), or bytaking samples of mud, vegetation andwater from a site and keeping them in a fishtank. Once the sediment has settled withinthe tank, you can use dark and lightbackgrounds and a magnifying glass tohunt for them. If you have only sampledjuveniles, it will take several weeks beforeyou see anything. Most will start out life asbarely visible dots moving jerkily up anddown the walls of the tank.

Calanoid copepods are one of the better-studied groups of microcrustaceans.Understanding their ecology can help assessthe health of the habitats they live in.

Simocephalus sp. is one of the largestcladocerans. This individual is full of asexuallyproduced eggs.


Some of the larger cladocerans found inwetlands can grow to a length of5 or 6 mm. Most species, however, rarelyexceed 2 mm. Some of the smaller familiesfrom this group have reduced antennae (e.g. Chydoridae) but often these animalsare too small to see and are therefore notdealt with here.

Possible misidentificationsWithout sufficient magnification, many ofthe microcrustaceans will look the same.The cladocerans are much rounder-lookingthan the copepods, and females keep theireggs internally rather than having distinctbundles of them attached to theirabdomens—a distinctive copepod trait.

Classification and distributionThe taxonomy of the cladocerans is stillunsettled but there are at least 150 speciesfrom over 40 genera in Australia.

Habitat and ecologyCladocerans feed mainly on detritus, bacteriaand algal particles, drawing them into thecarapace with a current of water driven byrows of fine legs. Some are found in or near

the benthos, while others are found in openwater as part of the plankton community.

Natural historyCladocerans can reproduce very quickly andthis allows them to follow their main foodsources: bacteria and algae. Their averagelife span is around one-and-a-half monthsand they can reproduce within one to twoweeks of hatching. This rapid reproductionis usually performed asexually byparthenogenetic females. The femaleproduces large quantities of eggs, hatchesthem within her carapace, and releases themduring a subsequent moult.

Many cladocerans live in temporary pondsor wetlands that dry out each year and theysurvive these harsh, dry periods as sexuallyproduced eggs. The female will thicken asection of the carapace known as the‘ephippium’ and this protects the alreadyresilient eggs. The eggs stay in the casing ofthe female after she has died and wait untilthe pond or wetland next fills up.

Cladoceran eggs are resistant to drying,freezing and digestive juices, and this allowsthem to be distributed throughout an

astounding range oflocations. They can beblown with fine sedimentsby the wind, or passedthrough the digestive tractsof larger animals such asbirds that travel betweenwater sources. Cladoceraneggs are also very long-lived. They have beensuccessfully hatched frompond sediments that havebeen dry for 200 years.

Most cladocerans such as this Simocephalus sp. feed on micro-scopic algae and these can make the digestive tract a vivid green.


Copepods (Subclass: Copepoda)

Distinguishing characteristicsMost copepods are extremely small (less than 2 mm), with the exception ofseveral species from the order Calanoida(around 4 mm). Their bullet-shaped bodiesare made up of a head segment, which isslightly longer than the other segments,followed by a simple thorax of cylindricalsegments, and a slightly thinner abdominalsection. Their most striking characters aretheir antennae (often long), the singledorsal eye, and the bundles of eggs thatmature females carry. Some species arebrightly coloured, but most are a mixture ofclear and brown-green.

Cyclopoid and calanoid copepods moveusing oar-like strokes of their antennae inopen water coupled with pulses of theirmultiple legs, while harpacticoid copepodswriggle their bodies over surfaces.

Possible misidentificationsSee Cladocera.

Classification and distributionThere are three orders of copepods:Calanoida, Cyclopoida and Harpacticoida.

Habitat and ecologyThe cyclopoid and the harpacticoid copepodsare both predominantly benthic, whilecalanoid copepods are usually planktonic.Most of them are herbivores/detritivores,feeding on algae and bacteria. Some of thelarger calanoid and cyclopoid copepods arepredatory, feeding on a mix of zooplanktonincluding other smaller copepods.

Natural historyMost copepods live for less than twomonths and reach maturity within the first

three weeks. Calanoid and harpacticoidfemales carry single bundles of eggs, whilethe cyclopoid copepods have paired eggbundles attached to their abdomens. Theirantennae serve as oars propelling themthrough the water, but also play a role inreproduction and predator avoidance.

Male copepods have hinged antennae onone side, which are used to clasp the femaleduring moments of passion.

Female calanoid copepods carry a singlebundle of eggs in the middle of their abdomen(Boeckella major).

Female cyclopoid copepods carry a doublebundle of eggs, which gives them a verydistinctive outline.


Distinguishing characteristicsClam shrimps have a small multi-segmentedbody enclosed in two valves, making themlook a lot like a bivalve. The body is covereddensely with around 10 to 30 pairs of legsand the shell is usually sculptured withconcentric growth lines. (The familyLynceidae is an exception to this.)Conchostracans come in a variety ofcolours, from blue to brown, or translucentforms. They can grow larger than 10 mm.

Possible misidentificationsConchostracans are very similar inappearance to ostracods: they differ bysometimes having growth lines, usuallybeing larger in size and by having morethoracic legs.

Classification and distributionThere are more than 20 species in Australia,but most of them are uncommon. Thecommonest is a large wetland genus,Limnadopsis, which has a distinctivelyridged shell.

Habitat and ecologyConchostracans occur in a variety oftemporary waters. They areherbivores/detritivores, filter-feeding using a current generated by the mess oflegs within the shell. Their eggs are capableof resisting desiccation through prolongeddry periods.

Clam shrimp (Order: Conchostraca)

Clam shrimps look a lot like small freshwatermussels, but they usually have slightly moretranslucent shells and many more legs. This is Limnadia sp.

Inside their shells, conchostracans have a distinctly crustacean shape, including a rostrum andantennae. This is Cyzicus sp.


Seed shrimp (Class: Ostracoda)

Distinguishing characteristicsThe bodies of the seed shrimps are totallycovered by two valves of the carapace, in thesame way as the less commonconchostracans. Ostracod carapaces areextremely variable—they carry sculpturingsuch as pits or ridges and can occur in awide variety of colours. Ostracods propelthemselves with an assortment of legs andantennae, which are thrashed around in thegap between the two valves. Whenthreatened, these appendages are retractedand the sealed shell drops to the ground.They are mostly smaller than 2 mm thoughthere are larger species.

Possible misidentificationsSee Conchostraca.

Classification and distributionOstracods are fairly diverse and distributedacross temperate Australia in still and (to alesser extent) flowing waters. There arearound 200 described species in Australia.

Habitat and ecologyOstracods are herbivore/detritivore filterfeeders. They are commonly found on thesoft sediments at the bottom of ponds andwetlands, though some species do travel inopen water or even on the underside of thewater surface.

Natural historyThe valves of ostracods fit together wellenough to allow the adults to survive short-term drying, but the eggs are more tolerantand can survive in dried sediments forseveral years.

The variety of sculpturing on ostracodshells means that it is sometimes possible toidentify them from their shell alone. This

fact, coupled with the way that the old shellsof dead animals can collect in layers underwetlands like shells on a beach, has helpedscientists discover how ostracods lived inwetlands thousands of years ago. Each of theostracods has a set range of conditions thatit can live in, including temperature, salinityand acidity. Knowing these tolerance levelsallows scientists to make estimates of pastclimates from the different collections ofostracod shells that they find in wetlands.

Some ostracods are light sensitive. The tiny lenson the side of their shell covers a simple eye.

Ostracods move using an assortment of legsand antennae. Several of these can be seenoutside the edges of their shell. The light spotsin the centre of the shell show where the musclethat closes the shell is attached.


Assorted crustaceans: amphipods,isopods, syncarids, brine shrimp andtadpole shrimp

Primitive crustaceans tend to have more legs than those that have evolved morerecently. Syncarids, brine shrimp and tadpole shrimp all have numerous pairs of legsand closely resemble their geologically ancient ancestors found as fossils around theworld.

These crustaceans are grouped together because of their similar overall structure. Amphipods areby far the most common, followed by the isopods. Syncarids are encountered in Tasmania, brineshrimps (Anostraca) are found in inland saline pools and wetlands, and tadpole shrimps(Notostraca) occur in wetlands all over the continent.

SYNCARIDA

ANOSTRACA

ISOPODA

AMPHIPODA

NOTOSTRACA

antennae

gnathopods

pleopods

uropods1 2 3

telson

peduncle

ramus (plural rami)

pleotelson

Assorted crustaceans l 69

Distinguishing characteristicsAmphipods are laterally compressed(flattened from the sides) and, when resting,have a rounded profile. They have relativelyshort bodies, with seven pairs of walkinglegs followed by three pairs of small,feathery swimming limbs known as‘pleopods’. They have two pairs of antennaeand a pair of eyes made up of severalsmaller eyespots. They come in a variety ofcolours, from light greens and greys to redsand blues. Amphipods vary in size, fromabout 5 to 25 mm.

Possible misidentificationsSee Isopoda.

Classification and distributionSeven families of amphipods are foundthroughout the inland waters of south-eastern Australia. The Talitridae occur in-frequently, as they live on the edges of waterand are sometimes sampled after they fall orare washed into streams. The Ceinidae andEusiridae are common throughout, usuallybeing represented by the genera Austro-chiltonia and Pseudomoera respectively.

Side swimmers or scuds (Order: Amphipoda)

Male amphipods lock themselves to theirpartners during mating. The female is thesmaller of the two. (Family: Paracalliopiidae).

Talitrid amphipods spend most of their time onland but near water, so they are sometimeswashed into rivers.

Sometimes ceinid amphipods can be orange,this one is from a drying wetland(Austrochiltonia sp.).

Ceinid amphipods are usually green, and liveamongst water plants. Females carry their eggsunder a set of plates between their walking legs.This is Austrochiltonia sp.


The eusirid amphipod Pseudomoera sp. is oneof the commoner amphipods in Victoria.

Corophium sp. is found in some estuaries inTasmania. Most of the members of this familyhave muscular antennae for gathering food.

Amphipods spend much of their time upsidedown and sideways (Antipodeus sp. Family:Paramelitidae).

Neoniphargids resemble paramelitids, but theyoccur in odd habitats like buttongrass ponds,alpine streams, and small coastal streams.

The corophiids are found in some coastalstreams of Tasmania and Queensland, sothey might turn up in coastal New SouthWales and Victoria. The paramelitids arefairly widespread, with four genera in south-eastern Australia, the commonest beingAustrogammarus. The Neoniphargidae andParacalliopiidae are less common. Theneoniphargids are a diverse group, withseven genera from south-eastern Australia.They occur in a variety of odd habitatsincluding caves and crayfish burrows. Whenthey do occur in streams, they turn up intrickles and very small headwater streams.Paracalliope, the only genus of theParacalliopiidae, occurs in Tasmania andpossibly in Victoria.

This family is sometimes grouped with theEusiridae. It can be found in buttongrassponds and small alpine lakes.

Habitat and ecologyMost Australian amphipods are found instill to slow-moving waters. They are allomnivorous, feeding predominantly ondecaying vegetation though they willopportunistically feed on other animals.They are usually shredders, but can use arange of feeding methods including filterfeeding and grazing. The Corophiidae andthe Ceinidae are typically found in slightlymore saline waters (often coastal) thanamphipods from the other families.


HistoryIn the Cretaceous period (around 90 mya)global temperatures were around 10°Cwarmer and the sea covered large areas ofinland Australia, reducing south-easternAustralia to two large islands: the GreatDividing Range and Tasmania. Large tractsaround the South Australian border withVictoria and in Gippsland were reduced tolow-lying swamps. The freshwateramphipods were restricted at this stage.Later, as the sea receded, salt-tolerantgroups, such as the ancestors of theCeinidae and Eusiridae, filled in the gaps inthe freshly uncovered river systems, whilethe primitive freshwater amphipods(Neoniphargidae and Paramelitidae)

were stranded in the mountainous parts ofsouth-eastern Australia.

Natural historyMale amphipods guard their mates closely,locking themselves to their partners withtheir second gnathopods (claws). In thesepairs, the smaller animal is the female.Females lay eggs after they have moulted,so males couple with females before theymoult, mate with them, and then guardthem until fertilisation is complete. Oncefertilised, the eggs hatch and the juvenilesundergo a few moults within the female’smarsupium (a set of plates that cover theeggs), before being released into the outsideworld when the female next moults.

Key to the families of amphipods

1 second antennae much longer than first . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Talitridae1 first antennae longer than second, or antennae equal lengths . . . . . . . . . . . . . . . . . . . . 2

2(1) live animals green, or sometimes orange; telson elevated by fleshy triangle, third uropods strongly reduced, without rami . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ceinidae

2 live animals not green or orange, other characters not as above . . . . . . . . . . . . . . . . . . 3

3(2) seventh leg very long, longer then sixth, final segment long and hairy, can break off (Tasmania only, buttongrass ponds, sometimes estuaries) . . . . . . . . Paracalliopiidae

3 seventh leg not much longer than others . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) live animal has lateral stripes, or with a darker middle band; both rami of third uropod a similar size; accessory flagellum of first antennae minute or absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Eusiridae

4 live animal uniformly coloured, grey to fawn; inner ramus of third uropod smaller than outer or absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5(4) animal slaty black-grey, with a matt finish, slightly compressed dorso-ventrally; only found in or near estuaries; telson entire . . . . . . . . . . . . . . . . . . . . . . . . . . Corophiidae

5 animal colour grey to fawn, animal not dorso-ventrally compressed, surface shiny; never in estuaries; telson cleft or notched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 . . . . . . . . . . . . . . . . . . . . .(anonymous grey amphipods, microscope required)

6(5) sternal gills sausage-shaped or absent (fairly common) . . . . . . . . . . . . . Paramelitidae6 sternal gills dendritic (found in sphagnum bogs, crayfish burrows, and caves)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neoniphargidae

NB: Amphipods are arranged within this key in order of difficulty. The last three families are almost impossible to separate without a microscope.


Water slaters or sow bugs (Order: Isopoda)

The janirid isopods have a distinctly roundedfinal abdominal segment (Heterias sp.).

The sphaeromatids are quite common in theestuarine parts of rivers.

Distinguishing characteristicsIsopods are usually dorso-ventrallycompressed (flattened from above) andgenerally resemble their best-knownrepresentative, the garden slater orwoodlouse. The phreatoicids are anexception to this rule and they look morelike over-stretched amphipods.

Possible misidentificationsAlthough many isopods are dorso-ventrallycompressed (flattened from above), thephreatoicid isopods have quite flat sides andthis can make them look like amphipods.Phreatoicids are usually more elongate thanamphipods and have their final segmentsfused together to form a pleotelson. (Seefigure, page 68.)

Classification and distributionFour suborders of Isopoda are found in theinland waters of south-eastern Australia.The Asellota is represented by a singlefamily, Janiridae, with a single genusHeterias. These animals are quite commonin lowland, slightly saline systems and arequite distinctive in appearance. TheFlabellifera is a group of parasitic animals,from large lowland rivers such as theMurray.

The Oniscidea is represented by twofamilies: Oniscidae and Styloniscidae. TheOniscidae is represented by a single genus,Haloniscus, which occurs in saline lakes,while the Styloniscidae is a predominantlyterrestrial group with a few amphibiousmembers from billabongs and ponds alongthe lower Murray River and somerainforest streams in Tasmania. ThePhreatoicidea is a diverse group, withfamilies present in a variety of cryptichabitats. Most of the Isopoda of inlandwaters occur in lowland systems, wheresalinities are slightly higher. The suborderPhreatoicidea is an exception, occurring ina variety of streams in Tasmania and in anumber of odd habitats throughout south-eastern Australia including: sphagnumbogs, crayfish burrows, tarns, caves andground waters.

Habitat and ecologyMost isopods are detritivores, shredders ofleaves and other organic matter, althoughthere are some notable exceptions: twofamilies of isopod from the suborderFlabellifera are parasitic. The cirolanids areectoparasites of freshwater shrimp and thesphaeromatids can be parasites onfreshwater fish.


Syncarids (Superorder: Syncarida)

Some isopods are parasitic on othercrustaceans. The cirolanids attach themselvesto freshwater shrimp and prawns with theirstrongly hooked legs.

The phreatoicid isopods are a diversefreshwater group. Common stream generainclude Uramphisopus and Colubotelson.

Distinguishing characteristicsSyncarids look a bit like a cross between ashrimp and a millipede. They are distinctivein their lack of a carapace (fused segments),together with the presence of small leg-likeprocesses (exopodites) on each of theirwalking/swimming legs. There are twocommonly encountered families: theanaspidids have their eyes on stalks, whilethe koonungids have simple eyes which sitflush with their first body segment. Most ofthe syncarids are fairly small (<20 mm),though the mountain shrimp (Anaspidessp.) can grow to around 50 mm.

Possible misidentificationsSyncarids superficially resemble freshwatershrimp, but they lack the fused segments atthe front of the body which form a carapacein shrimp and other decapods.

Classification and distributionWithin the superorder Syncarida, there arethree orders: Palaeocaridacea, Bathynellaceaand Anaspidacea. The order Palaeocaridaceawas last recorded from the Carboniferous(320 mya) and is now extinct. The orderBathynellacea occurs underground, in cavesand groundwater throughout south-eastern

The mountain shrimp, Anaspides tasmaniae iscommon in high altitude streams in Tasmania.

Anaspides also occurs in streams underground.This animal is from Exit Cave.


Australia and worldwide. Two families fromthe order Anaspidacea (Stygocarididae andPsammaspididae) also occur in caves andgroundwater, while the Anaspididae mainlyoccurs in Tasmania and the Koonungidae in Victoria and in Tasmania. These twofamilies occur in surface waters.

The most commonly encountered membersof the Anaspididae are Anaspides, which livein the pools of Tasmanian mountainstreams. Their close relatives Paranaspidesoccur on the bottom of several large lakes inTasmania and their ‘little brothers’, theAllanaspides, occur in buttongrass ponds insouth-western Tasmania, often in or aroundthe entrances of crayfish burrows(Parastacoides sp.). Of the Koonungidae,only Koonunga is occasionally found inVictorian and Tasmanian rivers.

Habitat and ecologyThe syncarids are predominantly freshwateranimals, despite their marine ancestry.Many of them occur in caves and in groundwater amongst coarse gravels, so they are

not often encountered. Several members ofthe order Anaspidacea are, however, quitecommon in Tasmanian mountain streamsor buttongrass ponds. All of the members ofthe superorder Syncarida are thought to bedetritivores, but there are cases of Anaspidestasmaniae feeding on insects caught on thewater surface of lakes.

Natural historyAll members of the Bathynellacea occurunderground, in caves and groundwater.Their name, roughly translated from theGreek, refers to the ‘merciless depths’ atwhich they are found.

Anaspides come in a wide range of colours,despite there only being two species.Specimens vary through white, yellow andpink, to brown and black. To some extentthis seems to be related to theirsurroundings. Some of the darker animalscome from pools on the Tarn Shelf (MtField National Park), where the rocks anddecomposing vegetation in the pools are alldarkly coloured.

Allanaspides sp. is only found in small pondsamongst the buttongrass heath of south-western Tasmania.

Koonunga is a small syncarid found in streamsnear groundwater springs.


Distinguishing characteristicsThe two most striking characteristics of theanostracans are their mess of feathery legsand the fact that they swim upside down,with their legs uppermost. The saline species(brine shrimps) are usually a pink colourand are fairly small (<10 mm) while thefreshwater species (fairy shrimps) are muchlarger (<50 mm) and pink to cream.

Possible misidentificationsSome of the larger species could be mistakenfor amphipods, but the anostracans have along thin tail section, which gives them avery distinctive appearance.

Classification and distributionTwo genera of Anostraca are present in theinland saline waters of south-easternAustralia. One, Artemia, is introduced whilethe other, Parartemia, is native. A singlediverse genus, Branchinella, with aroundtwenty species, occurs in temporary pondsand wetlands throughout the continent.

Habitat and ecologyArtemia and Parartemia inhabit temporarysaline lakes. They lay drought-tolerant eggs,which hatch after they have been saturatedin water. The animals develop quickly andsoon mature to lay further eggs in the softsediments at the bottom of saline lakes. Asthe waters dry up the adults die, leaving thenext generation to spend the dry times asmicroscopic eggs.

Branchinella, the slightly larger wetlandspecies, employs a very similar lifestyle butnot at the same intense salinities. Allanostracans are filter feeders.

Natural historyThe introduced fairy shrimp Artemia salinanow dominates many of our coastalsaltpans. It is thought to have escaped fromaquaculture and hobby aquariums, where itis commonly used as fish food.

Fairy shrimps, brine shrimps or sea monkeys (Order: Anostraca)

Anostracans swim upside down, the pulses of their many legs pushing them forward.


Tadpole shrimp or shield shrimp (Order: Notostraca)

Distinguishing characteristicsThe front half to two-thirds of the body ofthese animals is a long shield, which coversthe thorax of the animal. The shield carriesa pair of compound eyes, followed by asmall lump, which is a nuchal organ (theequivalent of a nostril for burrowing-aquatic animals). Tadpole shrimp areusually brown coloured, with up to 60 pairsof legs on their underside, which propelthem powerfully but often spirally. Fullygrown animals can reach around 40 mm(body length without tails).

Classification and distributionTwo species occur in temperate Australia.The commonest is Lepidurus apus viridus,but Triops australiensis australiensis alsooccurs along the New South Wales/Victorianborder and in parts of Western Australia.Lepidurus has a short plate projectingbetween its two tails, while Triops has a flatend to its abdomen.

Habitat and ecologyNotostracans occur in wetlands that dry outfrom time to time. Their eggs are droughttolerant and are activated by the presence ofwater, not unlike those of the Anostraca.

Both species found in south-eastern Australiaare thought to be detritivores. They forageand live in the soft sediments of wetlands.

Natural historyLepidurus apus viridus tends to be found inspring in south-eastern Australia, whileTriops australiensis australiensis is anautumn animal. The adults live for about amonth, in which time they mate and laytheir microscopic eggs in the sediments.These animals tend to disappear fromwetlands that remain inundated for a longtime, but they return after a dry period.

The tadpole shrimp (Lepidurus apus viridis) hasaround 60 pairs of legs. Some of the anteriorpairs have pincer-like ends.

The tadpole shrimp (Lepidurus apus viridis)wriggles free of its old skin, through a gapbehind its head shield.

The carapace of the tadpole shrimp (Lepidurusapus viridis) has a small nuchal organ justbehind the eyes. It works a bit like a nostril.

Decapods l 77

Freshwater shrimp, prawns, crabs andcrayfish (Order: Decapoda)

Decapods are usually large, highly mobile animals. They are often the largestinvertebrates in a stream and as a result are an important part of the food chain.

ATYIDAE (shrimp)*

HYMENOSOMATIDAE (false spider crabs)

PARASTACIDAE (crayfish and yabbies)

*Note: Palaemonidae (prawns) are similar to Atyidae (shrimp) but have long, robust second legs.


Characteristics of a decapod crustaceanThe most distinctive features of decapodsare their stalked eyes and their 10 legs.In many, this includes at least one pair oflegs with pincer-like endings (chelae),though the Atyidae sport a pair of brushesas well. The smaller and finer limbs in frontof the legs are mouthparts and antennae,while those behind the legs are known aspleopods and may help the animal to swim.

Eating and extinctionPrawns, shrimp, yabbies and crayfish featurein our cuisine. Various species of thepalaemonid prawn Macrobrachium arecultured in large ponds throughout Asia,while the Atyidae feature in a range ofshrimp-based dishes. In Australia, the yabbyis popular with aquaculturists, along withthe marron and the gilgie (also from thegenus Cherax). These animals maturequickly and reach an edible size within twoyears. Of the larger crayfish with harderexoskeletons, the genera Euastacus andAstacopsis include a number of species thathave been extensively fished over the lastcentury. This has led to several speciesbecoming endangered, as the compoundeffects of overfishing, habitat degradationand worsening water quality have takentheir toll. Most of these larger freshwater

crayfish are quite slow growing and can takeup to nine years to reach maturity.Larger specimens (around a kilogram inweight) can be upwards of 15 years old.Their slow growth rate makes theseanimals very susceptible to overfishing.Fortunately, many of these species are now protected.

Marine invadersCrustaceans were originally a marine groupof animals so many of our freshwaterdecapods resemble their not-so-distantcousins from the sea. The lower salinities of

The Glenelg crayfish, Euastacus bispinosus, hassuffered a serious decline in numbers as aresult of overfishing.

Key to the families of Decapoda

1 main body of animal flat and round, length similar to width, tail folded under and inconspicuous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hymenosomatidae (p. 81)

1 main body longer than wide, animal with a distinct tail . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2(1) robust animals, with front claws much more robust than other legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parastacidae (p. 82)

2 delicate animals, front claws slender, not much thicker than other legs; if robust claws are present, they are the second rather than first pair of legs . . . . . . . 3

3(2) second pair of legs long, and strongly chelate (with pincers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Palaemonidae (p. 81)

3 front legs chelate, but with brushes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Atyidae (p. 80)

Decapods l 79

freshwater have meant that freshwaterdecapods possess a very different physiologyto their marine ancestors, and have adaptedtheir lifecycles slightly. Marine decapodsoften have a long-lived planktonic stage,where the young drift off to sea and wash up(sometimes years later) on a different bit ofcoast to their parents. In rivers, a long-livedjuvenile would end up lost at sea, so mostfreshwater decapods have given up theirplanktonic ways and the young start life assmaller versions of their parents, completewith claws and strong legs. In south-easternAustralia the decapod invasion hascontinued a little further, with many of thecrayfish coming up onto land and in somecases building themselves permanent homeswithin it.

Environmental significanceDecapods occur over a wide range of waterqualities. Some preferring slightly saline

conditions, while others occur in mountainstreams. This makes their general presence alittle ambiguous when monitoring waterquality. The distributions, biology andenvironmental tolerances of many species ofthe Parastacidae are well studied, however,and they can be useful indicators of streamdegradation at the local scale.

Classification and distributionThe order Decapoda is represented in thefreshwaters of temperate Australia by fourmajor families, Parastacidae (crayfish),Palaemonidae (prawns), Atyidae (shrimp)and Hymenosomatidae (false spider crabs).A simple key to the families of decapods insouth-eastern Australia appears opposite.Two extra families, Grapsidae andSundathelphusidae, that are strongly relatedto the marine shore crabs, occur in tropicalAustralia. The palaemonids do not occur insouthern Victoria or Tasmania.

Level-headed crustaceans Most decapods have a pair of sensoryorgans called statocysts, which work a bitlike our inner ears to keep the animalupright. The base segments of the firstantennae have a pore, the inside of which is lined with lots of small sensory hairs.This tiny chamber also contains a smallstructure made from sand grains, called astatolith. When the animal is horizontal,the statolith sits squarely on a set of hairsin the base of the statocyst. If the animal istilted (during swimming, or while climbingbanks), the statolith moves onto a differentset of sensory hairs, which warns theanimal that ‘up’ is now in a differentdirection. The whole system helps withnavigation in waters that can sometimesbecome very murky. When decapods shedtheir skins, they lose their statoliths andhave to get new ones. Some decapods do

this by rubbing their antennal bases insand while the new skins are still soft, whileothers are actually capable of carefullyputting new sand grains into the poreswith their smaller pincer legs.

A pair of sensory organs at the base of the firstantennae helps to keep decapods upright.


Distinguishing characteristicsAtyids are translucent and can be mottledwith blues, greens and darker markings.Stressed or dead animals become opaqueand either white or pink, like cookedprawns. The front two pairs of legs of theatyids bear distinct brushes. Most membersof this family are around 2–4 cm when fullygrown, but some of the cave-dwellinggenera are slightly smaller.

Possible misidentificationsDamaged animals lacking the front twopairs of legs might superficially resemble thePalaemonidae or even young yabbies. Bothof these families are usually more robustthan the Atyidae and are also lesstranslucent.

Classification and distributionTwo genera of Atyidae occur in south-easternAustralia. Paratya has one species, Paratyaaustraliensis, the commonest freshwatershrimp in temperate Australia. The genusCaridina has eight species but these animalsare less common than Paratya australiensis.They do not occur in Tasmania.

Habitat and ecologyAtyids occur in the slower flowing(lowland) rivers and in ponds andbillabongs. They feed mainly on detritus,fine decomposing vegetation, bacteria andalgal particles, pulling them into theirmouthparts with the brushes on the firsttwo pairs of legs.

Natural historyParatya australiensis benefits from theseasonal drying of many of the rivers itoccurs in. As the rivers is reduced to a seriesof poorly connected pools, it starts to breed.

Atyid shrimp have aplanktonic stage forthe first months oftheir lifecycle. Thesmall and fragileyoung grow up oversummer in thesheltered pools and bythe time the riverstarts to flow again inspring, they aredeveloped enough tohandle the rivercurrents.

Freshwater shrimp (Family: Atyidae)

The freshwater shrimp Paratya australiensis hasits front two pairs of legs ending in fine brushes.

Female shrimp carry their eggs under their abdomen. The pleopods keepa flow of fresh, oxygenated water passing over them.

Decapods l 81

Distinguishing characteristicsPalaemonids have their second pair of legsmuch longer than the first and these end ina robust set of pincers. Their bodies aretranslucent to opaque with darker brown toblue markings. They are usually slightlylarger than the Atyidae and can measurearound 6–7 cm when fully grown,sometimes with claws the same size again.

Possible misidentificationsYoung, or damaged specimens can resembleAtyidae. Check the front two pairs of legs.

Classification and distributionOne genus, Macrobrachium, is common intemperate Australia. Several species occur inNew South Wales, northern Victoria, WesternAustralia and South Australia, the mostcommon being Macrobrachium australiense.While the freshwater palaemonids do notoccur in southern Victoria or Tasmania,their estuarine relatives can sometimes befound in the lower ends of rivers.

Habitat and ecologyPalaemonids are scavengers that feed on amixture of decaying plant and animal

material. They use their first and third pairsof legs, reserving their second, enlarged pairfor self-defence and settling territorialdisputes. They occur in lowland rivers,ponds and billabongs and are usuallyassociated with snags or vegetation.

Natural historyThe family Palaemonidae includes a numberof common marine genera as well. Thecommon rock pool shrimp (Palaemon spp.),and red-clawed shrimp (Palaemonetes spp.),can be found in inter-tidal rock pools andare common in sea grass and in estuaries.

Freshwater prawns (Family: Palaemonidae )

Palaemonid prawns (Macrobrachium sp.) have avery long second pair of claws. They feed withthe first pair, which are much shorter.

Distinguishing characteristicsThe hymenosomatid crabs have adistinctive, round shape when viewed fromthe top. Their front legs are modified toform pincers. They are usually brown togrey, often with a fine covering of algae ontheir carapaces. They grow to around 2 cm.

Classification and distributionOne genus, Amarinus, is found in freshwaterthroughout south-eastern Australia.

False spider crabs (Family: Hymenosomatidae)

A pair of freshwater crabs (Amarinus lacustris)settle a dispute.


Habitat and ecologyAmarinus lacustris lives in a variety ofhabitats from slightly saline streams to lakes.It feeds on detritus and can be found inlarge numbers on snags in some lowlandstreams, or under and around rocks in lakes.

Natural historyOther crabs from the genus Amarinuscommonly occur in estuaries, suggestingthat this is perhaps where the ancestors ofthese freshwater crabs started out. Amarinusis Greek for ‘not from the sea’, referring to itsestuarine habits. The name is perhaps morerelevant for the freshwater species. Thename ‘lacustris’ refers to the lake habitats inwhich the first specimens were found.

Distinguishing characteristicsThe parastacids have their front legsmodified to form robust claws. The followingfour pairs of legs are attached to the maincarapace, which is followed by a multi-segmented abdomen ending in a tail fan.

Classification and distributionThe parastacids occur throughout south-eastern Australia, with 7 genera and around80 species (more are likely as the taxonomyof various groups is revised).

Habitat and ecologyParastacids occur in a wide variety ofhabitats including swiftly flowing streams,billabongs and some even build semi-terrestrial burrows. Crayfish are by far thelargest invertebrates in freshwater systems.They are omnivorous, feeding on a range ofrotting vegetation, together with fish andother aquatic animals that stray too near.

Freshwater crabs’ legs end in a pointedsegment which makes them excellent climbers.They are sometimes found on woody debris inlowland rivers (Amarinus lacustris).

Freshwater crayfish and yabbies (Family: Parastacidae)

Astacopsis gouldi, the world’s largestfreshwater crustacean, comes from Tasmania.

Cherax destructor is one of the commonestcrayfish in south-eastern Australia.

Decapods l 83

Natural historyAlthough they prefer to be under water,yabbies (Cherax genus) are one of the fewlarge crustaceans able to survive the regularAustralian phenomenon of drought. Manyyabbies can aestivate, which involvesslowing down their metabolisms andburying themselves deep in moist sedimentsto keep their gills from drying out.

Burrowing crayfish (genera: Geocharax,Engaeus, Gramastacus, Cherax andParastacoides) employ a similar trick. They

burrow into the soil in damp areas such asswamps, or the banks of rivers. Often theexcavated soil is piled around the entranceof the burrows forming a distinctivechimney. The tunnels of burrowing crayfishoften have many branches, some of whichare totally filled with water. The inhabitantseat the vegetable matter they encounterwhile burrowing (predominantly roots) andthe odd uncovered worm. Some arenocturnal and will leave their burrows toforage at night.

The Murray River crayfish (Euastacus armatus)has a medieval assortment of spines.

Engaeus sp. is found throughout south-eastern Australia. It makes its burrow near a creek.

The ‘chimney’ at the entrance to the home of aburrowing crayfish. [Photo: Niall Doran]


Distinguishing characteristicsSpringtails are minute animals, rarely largerthan 3 mm long. They vaguely resembleinsects as they have a head with a pair ofantennae, a thorax with three pairs of legsand a segmented abdomen. However, theyhave soft bodies without a hard exoskeletonand they lack wings. Unlike insects, theyhave a forked spring-like appendage(furcula) attached to the underside of theabdomen. This spring is held under tensionby another appendage, which acts as atrigger. When the ‘trigger’ is released the‘spring’ catapults the animal, often as far as

30 cm. Springtails can jump so quickly thatthey seem to disappear in front of your eyes.Springtails also have another appendageattached underneath the body but nearer thehead. It was believed that this appendagehelped them stick to the surface (hence thename Collembola, from the Greek colle, glue,and embolon, piston) but it is also involvedwith excretion and internal water balance.

Possible misidentificationsSpringtails may resemble the juveniles ofsome insects but their unique forked springshould be enough to separate them.

Springtails (Class: Collembola)

Springtails look like tiny insects and were once regarded as a primitive insect group.However, these soft-bodied invertebrates have now been placed in a separate class.

Rafts of springtails like this can be a common sight after summer rains.

Springtails l 85

Classification and distributionAlthough the class Collembola is one ofthe most widely distributed groups ofinvertebrates, with more than 1600 speciesknown in Australia, the only exclusivelyfreshwater aquatic species of springtails inAustralia belong to the genus Sminthurides(Family: Sminthuridae, Order:Symphypleona). One of the more commongroups that can be washed into watercoursesis the family Hypogastruridae. Members ofthis family are generally found in leaf litterand soil but are often washed into streamsin large numbers by rain and form the ‘greyrafts’ sometimes seen in puddles.

Habitat and ecology of aquatic formsMany species of springtails have an affinityfor moist conditions and live at the edges ofaquatic habitats where humidity approachessaturation. Most of the springtails found inrivers and ponds are washed by rain intodrainage waters. The fully aquatic genusSminthurides grazes on diatoms on the watersurface, while most other collembola feed onfungi and on decomposing organic matter.

Natural historyThe waterproof skin of most springtailsprevents them from getting waterloggedand allows them to float. Terrestrialspringtails may use running water as ahighway to disperse and occupy newhabitats. Most springtails reproducesexually. Males deposit sperm sacs on the water surface, which are picked up by the females.

During the hot and dry Australian summerspringtails burrow into the soil and lowertheir metabolism. During this period theydo not feed. In autumn, a range ofenvironmental cues brings them back tothe surface layers of soil to feed andreproduce. During this time, the autumnrains wash a large number of them into the water.

In the northern hemisphere large numbersof springtails migrate long distances oversnow during early spring. Triggered byrising temperatures, they emerge from thedeep snow and follow the movements ofthe sun on their voyage.

Collembola have a large number of insect characteristics, but their obvious spring organ and theirsoft wrinkly skin allow distinction.


Distinguishing characteristicsAquatic caterpillars come in several forms,but the most commonly encountered speciesare portable case builders in dams, billabongsand slow-moving rivers. These animals havefleshy bodies, short, segmented legs and asclerotised head capsule. They are oftencovered in gills and these can be simple orbear multiple branches. The underside ofthe abdomen usually has a couple of rows of stocky pro-legs, ending in circles of smallhooks or crochets. The cases are coarselystitched (compared to most caddis cases)and incorporate large flat pieces of leaf, orlots of longitudinal pieces of finer weeds.Some aquatic caterpillars prefer fast-movingwater and correspondingly adopt a verydifferent form. These animals are robust,slightly flattened animals, often with gills.They build a silken retreat attached tostones within the stream. Most aquaticcaterpillars grow to less than 20 mm long.

Adults are small triangular moths with grey-brown and cream patterned wings.

Possible misidentificationsAquatic caterpillars share many of theircharacteristics with beetle larvae, but theselack the abdominal pro-legs of caterpillars,with their circles of crochets or small hooks.Riffle-dwelling lepidopterans could also beconfused with some of the uncased caddislarvae such as hydropsychids, but theseanimals also lack crochets and their headsare much less broad.

Classification and distributionThe aquatic caterpillars all belong to thefamily Pyralidae and the subfamilyNymphulinae. There are around 50 speciesfrom 15 genera, but the taxonomy—particularly of the larvae—is still inprogress. These groups tend to be morediverse in the tropics.

Aquatic caterpillars (Order: Lepidoptera)

Caterpillars—the larvae of moths and butterflies—are a diverse and widely distributedgroup, so it is not surprising that some of them have managed to successfully adaptto freshwater habitats.

Sometimes aquatic caterpillars will use air-filledaquatic plants in their cases and this makesthem buoyant.

Adult pyralid moths have broad, triangular wingswhich are often patterned.

Aquatic caterpillars l 87

Habitat and ecologyThe aquatic caterpillars inhabit two verydifferent environments. Cased caterpillarslive in pools, ponds, lakes or billabongs, atlow altitude, where they eat aquatic plants.In contrast, the fast water caterpillars areoften found in cold alpine streams, wherethey feed on algae from the surface of rocks.

Natural historyLiving in freshwater is thought to be arecent evolutionary step for caterpillars and

there is some evidence for this in thenorthern hemisphere where a number ofspecies live a semi-aquatic existence. Theseanimals have cases that act like scuba tanksand contain sufficient air for the caterpillarsto survive underwater for prolonged periodsof time. In most of the Australian slowwater species, this contraption is no longernecessary due to their efficient gills, but itstill serves as camouflage and protectionfrom predators. Young larvae lack cases andlive as leaf miners.

The riffle-dwelling caterpillar (inset) shares many of the characteristics of its slow water relative.


Distinguishing characteristicsScorpionfly larvae are small slender animalswith a rectangular sclerite on their firstthoracic segment. The rest of their bodysegments are pale but shiny and slightlyhydrophobic. They have short jointed legson their first three segments, and a pair ofsimple hooks and a couple of gill filamentson their final segment. They move withstrong snake-like motions and their legs aremainly used for grasping prey. Larvae cangrow to about 15 mm long. The adults canbe found on vegetation near streams inspring. They have two pairs of coarselyveined wings and a bulbous end to theirabdomen.

Possible misidentificationsScorpionfly larvae superficially resemble theceratopogonids (see page 119) in their bodyshape and movement; but the legs are adead give-away.

Classification and distributionMost scorpionflies are terrestrial. A singleaquatic family, the Nannochoristidae, occursin Australia, New Zealand and SouthAmerica. A single genus, Nannochorista,with three or four species, occurs intemperate Australia.

Habitat and ecology Scorpionfly larvae are fast-movingpredators of other invertebrates in siltyenvironments. They occur more commonlyin small cool streams, either in silt depositsat the sides of streams, or in silt-filled seepsand puddles beside the main stream.

Natural historyScorpionfly larvae move using their bodiesin a snake-like motion. This propels themquickly through the relatively thick silt inwhich they live. They are highly sensitive tomovements that disturb the silt and respondquickly to the frantic movements ofcommon prey such as chironomid larvae.

Scorpionfly larvae (Order: Mecoptera)

Larger, terrestrial members of this order of insects hold their abdomens witha distinctly scorpion-like posture and this is where they get their name.

Scorpionfly larvae are fast-moving predators,but the adults (inset) have simple mouthparts,suggesting that they have a liquid diet.

Because of its long thin body, a scorpionfly larvais sometimes mistaken for a biting midge larva.

Toebiters l 89

Distinguishing characteristicsMegalopteran larvae are robust animals,with heavily sclerotised heads and thoracicsegments. Their abdominal segments arefleshy and have long filaments on eitherside. Their legs are robust and jointed andtheir abdomen ends in either a single, hairfringed filament (alderfly larvae, Family:Sialidae), or a pair of clawed pro-legs(dobsonflylarvae, Family: Corydalidae).Sialid larvae grow to around 20 mm and thecorydalid larvae to around 30 mm. Theadults are large ponderous animals withtranslucent, spotty wings.

Possible misidentificationsWhirligig beetle larvae (Family: Gyrinidae)have very similar lateral filaments, but theyhave filaments on all 10 abdominalsegments and are quite sleek, while thecorydalids only have them on eightsegments and the sialids on seven (notincluding the terminal filament).

Classification and distributionThe family Corydalidae is represented bythree genera and seven species in temperateAustralia. One of these genera, Apochauliodes,is restricted to southern Western Australia,while Protochauliodes and the commonerArchichauliodes are distributed throughoutsouth-eastern Australia. Corydalids do notoccur in Tasmania.

Sialidae is represented by two species,Austrosialis ignicollis in Tasmania andStenosialis australiensis in south-easternAustralia.

Habitat and ecologyBoth the corydalids and the sialids arepredators. Corydalids live in fast-flowingwaters amongst cobbles and pebbles; sialidsare a slow water animal typical of pools.

Natural historyThe New Zealand toebiter Archichauliodesdiversus is intriguing in its habit of leavingthe stream to moult after every instar. Thislaborious behaviour has not been observedin Australian toebiters, but much of theirlife history is still unknown.

Toebiters (Order: Megaloptera)

Some of the largest freshwater invertebrate predators belong to this fearsomegroup of insects. They are quite common in the cobble streams of mainlandsouth-eastern Australia.

Corydalids are large predators amongst thecobbles of fast-flowing streams.

Sialids have a single filament at the end of theirabdomen.


Distinguishing characteristicsThree distinct families of Neuroptera areaquatic. The sisyrids are small (<5 mm)pudgy animals with long outwardly curvedmouthparts. Their bodies are covered withpale sclerites and erect setae and they havetwo rows of folded gills on the underside oftheir abdomen. They have segmented legs,but move very slowly. The osmylids aremuch bigger (20 mm), darkly sclerotised and with outwardly curving mouthparts.They lack gills, but are similarly covered insetae and sclerites. Their abdomens end in arobust pair of hooked pro-legs andsometimes the entire larvae can have a blue-purple iridescence. The neurorthids areslender animals, with inwardly curvingmouthparts. Their sclerotised parts areusually a deep orange and they have adistinctively thin ‘neck’. The adults of allthree families are lacewings, with busilyveined wings. They are active predators.

Possible misidentificationsThe sisyrids and the osmylids are oddenough to be unmistakable. The neurorthidscould be confused with beetle larvae, butthey differ by having a distinctive neck.

Classification and distributionThe commonest member of the Sisyridaefound in temperate Australia is Sisyra. TheOsmylidae is a diverse group, including fourterrestrial subfamilies as well as the semi-aquatic Kempyninae. This subfamily

includes three genera, some of which areshared with New Zealand. TheNeurorthidae is a small family with a singlegenus found in south-eastern Australia.

Spongefly larvae, lacewing larvae (Order: Neuroptera, Families: Sisyridae, Osmylidae andNeurorthidae)

This order includes some of the strangest aquatic insects. They are usually quite rarebut very distinctive.

Sisyrids feed exclusively on freshwatersponges, which they probe with their slendermouthparts. The upper set of appendages onthis animal are antennae.

Osmylids are odd-looking animals. Usually landbased, they sometimes venture into water tohunt. Their water-repellent skin prevents thembecoming victims of surface tension.

Spongefly larvae, lacewing larvae l 91

Habitat and ecologyThe sisyrids are true spongeflies, feeding onsponge tissues with their odd, tubularmouthparts. They are restricted to waterwhere sponges occur: slow-moving or largerrivers and lakes. The osmylids are semi-aquatic and are thought to use their longmouthparts to probe for chironomid larvaein softer sediments. The neurorthids live infast-flowing streams and are thought to bepredators, but very little is known abouttheir biology.

Natural historyThe larvae of all lacewings have their fore-and mid-guts separated and they do notjoin up until pupation. This leaves theanimals effectively constipated untiladulthood.

Most adult neuropterans have a similar appearance and are known collectively as lacewings. They are often attracted to lights where they prey on smaller, slower insects such as aphids.

The neurorthids are one of the fastestmacroinvertebrates and this makes them bothefficient predators and difficult to photograph.


Distinguishing characteristics of adultsAquatic beetles can look very similar toterrestrial beetles. They both possess elytra,the hardened (sclerotised) modifiedforewings that cover the hind wings andabdomen. However, most aquatic beetlescan be separated from their terrestrialrelatives by the presence of swimming hairson their legs, and by their more streamlinedbody shapes. The diving beetles, forexample, have adopted a droplet shape andpaddle-like hind legs so that they can swimthrough the water more efficiently.

Beetles (Order: Coleoptera)

Beetles are the largest and one of the most diverse groups of animals on Earth withmore than 300,000 known species. Many of them have successfully colonisedfreshwater habitats.

antennae

maxillary palps

pronotum

scutellum

elytra

swimming hairs

Generalised aquatic beetle adultGeneralised aquatic beetle larva

Some water scavenger beetles, like thisHelochares sp., resemble terrestrial beetles.

mandiblesantennae

legs thoracicsegments

abdomengills

head

Beetles l 93

Despite living in the water, many adultbeetles have retained their ability to fly, andthis allows them to disperse quickly to newhabitats.

Distinguishing characteristics of larvaeBeetle larvae look very different from adultsand can vary greatly in their appearancefrom family to family. Most larvae areelongated and have three pairs of walkinglegs and a sclerotised head capsule withmouthparts and antennae. The larvae lackwing pads and have well-developed legs.

ClassificationThe great diversity of aquatic beetles oftenmakes them difficult to identify to familylevel. In this chapter we have included onlythose groups of beetles which are mostlikely to be found in aquatic samples. Wehave omitted groups which are relativelyrare (e.g. Chrysomelidae, Microsporidae,Noteridae) and groups which are not strictlyaquatic but wander in and out of the water(e.g. Carabidae and Staphylinidae).

Natural historyColeoptera means sheath-winged and refersto the elytra. This protective cover givesbeetles an advantage over other insects.Together with sclerotisation underneath theabdomen and thorax, it protects beetlesfrom desiccation, predation and mechanicaldamage to their body. Equipped with thisarmour beetles can occupy many differenthabitats.

Most aquatic beetles live in water as bothlarvae and adults. However, some familiessuch as Ptilodactylidae, Scirtidae andPsephenidae live in the water only as larvae,while most Hydraenidae are aquatic onlyduring their adult stage.

The lifecycle of beetles includes four stages:egg, larva, pupa and adult. Pupationcommonly occurs in soft mud andvegetation beside the water, but once adult

beetles have emerged they can return to the water. Adults play an important role indispersal, as many retain their ability to fly.Mating takes place in the water or near thewater. Some water scavenger beetles(Hydrophilidae) use calling signals underwater to find mates.

Beetle larvae have a variety of shapes andforms: the cockroach-like larva of Scirtidae (top),the flattened larva of Psephenidae (middle), andthe long-legged larva of Dytiscidae (bottom).


Key to beetle larvae

1 legs absent or very short; unsclerotised grub-like body, often found inside submerged aquatic plants . . . . . . . . . . . . . . . . . Curculionidae (aquatic weevils, p. 97)

1 not with the above combination of features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2(1) antennae longer than head and first thoracic segment combined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scirtidae (p. 111)

2 antennae shorter than head and first thoracic segment combined. . . . . . . . . . . . . . . . 3

3(2) gills present on ventral surface of abdomen . . . . . . . . . . . . . . . . . . Hygrobiidae (p. 108)3 no gills on ventral surface of abdomen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) eight abdominal segments visible from above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 nine or ten abdominal segments visible from above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5(4) body disc-like with dorsal plates covering head and legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Psephenidae (water pennies, p. 109)

5 body elongate, not disc-like; head and legs not covered by dorsal plates . . . . . . . . 6

6(5) legs longer than thorax; mandibles sickle-shaped without teeth on inner margin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dytiscidae (diving beetles, p. 98)

6 legs shorter than thorax; mandibles sickle-shaped, but with one or more teethon inner margin . . . . . . . . . . . . . . . . . . . . . . . .Hydrophilidae (scavenger beetles, p. 106)

7(4) body with nine abdominal segments visible from above, body slender, well-sclerotised, without any processes or gills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7 body with ten abdominal segments visible from above; body with processes or gills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8(7) abdominal segment 9 with a ventral flap (drawing A); usually small (<10 mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Elmidae (riffle beetles, p. 100)

8 abdominal segment 9 without a ventral flap (drawing B); usually larger than 10 mm with waterproof skin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ptilodactylidae (p. 110)

9(7) ten pairs of feathery gills on sides of abdomen; last segment narrow, with 4 hooks; length up to about 20 mm. . . . . . . . . . Gyrinidae (whirligig beetles, p. 102)

9 no feathery gills; dorsal surface with rows of short or thread-like processes; last abdominal segment narrow with long tail; length up to 6mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Haliplidae (crawling water beetles, p. 103)

A B C

Beetles l 95

Key to adult beetles

1 hind legs shorter than forelegs; mid and hind legs strongly paddle-shaped;found in schools on the surface of stagnant or slow-flowing waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Gyrinidae (whirligig beetles, p. 102)

1 hind legs much longer than forelegs; behavioural characteristics not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2(1) large coxal plates covering bases of hind legs and abdomen (drawing C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Haliplidae (crawling water beetles, p. 103)

2 no large hind coxal plates; bases of hind limbs exposed (drawing D) . . . . . . . . . . . . . 3

3(2) head with distinct snout (drawing E) . . . . . . . Curculionidae (aquatic weevils, p. 97)3 head without snout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) antennae club-shaped (drawing F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 antennae slender, bead-like or thread-like (drawing G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5(4) antennae 9-segmented with 5-segmented club; abdomen with 6 or 7 ventralplates; body length less than 4mm; maxillary palps are longer than antennaeor pronotum has laterally extending plates . . . . . . . . . . . . . . . . . . . Hydraenidae (p. 104)

5 antennae 7 to 9-segmented with 1-, 3- or 4-segmented club; abdomen with5 ventral plates; body length between 2 and 40 mm; if maxillary palps longerthan antennae then body length longer than 4 mm; no lateral plates onpronotum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6(5) pronotum narrower than base of elytra, dorsal surface strongly sculptured . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrochidae (p. 106)

6 pronotum not narrower than the base of elytra, dorsal surface not stronglysculptured . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrophilidae (scavenger beetles, p. 106)

7(4) legs not adapted for swimming; adults crawl; occur in well-oxygenated mostlyflowing waters; body size up to 5–6 mm . . . . . . . . . . . Elmidae (riffle beetles, p. 100)

7 hind legs adapted for swimming; body length variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8(7) eyes protruding; body stout and oval, 8–10 mm long; dorsal surface stronglyarched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hygrobiidae (p. 108)

8 eyes not protruding; size and body shape variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dytiscidae (diving beetles, p. 98)

D E

F

G


Aquatic adaptationsBeetles are one of the groups of invertebratesthat entered the aquatic environment afterliving and evolving on dry land for millionsof years. This evolutionary invasion of watermeant that beetles had to adapt to a newand very different environment.

Breathing while under water is one of themain problems for animals adapted to lifeon land. Some groups of beetles still relysolely on air while others have evolved touse oxygen dissolved in the water.Hydrophilid beetles and several othergroups have special hairs which trap an airbubble underneath their abdomen.

Dytiscid beetles store an air bubble undertheir elytra and return to the surface fromtime to time to replenish the air. Thisbehaviour gives them their common name,‘diving beetles’. Adult Elmidae (riffle beetles)use a plastron—a physical lung, formed byspecialised hairs trapping a very thin layer of air around the abdomen. As oxygen inthe layer is used, its concentration decreasescompared to the concentration of oxygen in the water. This causes the diffusion ofnew oxygen across the plastron. Because this system relies on high concentrations of oxygen in the water, plastron users arerestricted to well-oxygenated waters, usuallyshallow, swift creeks with cold water.

The body surface of some diving beetles is so smooth that males need suction discs on the ends oftheir front legs to hold a female during copulation. This is Onychohydrus scutellaris.

The layer of air underneath the abdomen of thehydrophilid Enochrus sp. shines underwater.

A diving beetle with a bubble of air at the tip ofthe abdomen.

Beetles l 97

Distinguishing characteristics of adultsThe head ends in a long snout. Antennae areattached to the snout, angled and have aclub at the end. Body size is up to 9 mm.

Distinguishing characteristics of larvaeLarvae are legless with a soft unsclerotisedbody except for the head capsule.Mouthparts are directed downward.

Possible misidentificationsBoth adults and larva are very distinct.The best distinguishing feature of the adultis the elongated head. Larvae can beconfused with some fly larvae and withlarvae of Chrysomelidae. A relatively largesclerotised head should help in separatingthe weevil larvae.

Classification and distributionThere are several genera of aquatic weevils.Many species are semi-aquatic. The genusBagous is quite common and has beenrecorded in all states and territories.The native species B. hydrillae has beenintroduced to the USA to help with thebiological control of an aquatic weed.

Habitat and ecologyBoth adults and larvae live in stagnant orslow-moving waters. Adult beetles crawlamong submerged water plants while larvaelive inside air-filled stems of aquatic plants.There is very little known about the biologyof Australian aquatic weevils. Both adultsand larvae are herbivorous.

Natural historyAdults lay their eggs within stem tissuesnear leaf joints. The larvae hatch in three tofour days and feed on the internal stemtissues. There are three larval instars eachlasting several days. The third instar larvaeexit and subsequently pupate in dry soil.

Larvae breathe air obtained from inside theplant stems while adults use a combinationof plastron respiration and breathingatmospheric oxygen when oxygen saturationin the stagnant water becomes limiting.

The head of a curculionid has a characteristicsnout.

An adult Bagous sp. Is up to 9 mm long.

Aquatic weevils (Family: Curculionidae)


Distinguishing characteristics of adultsAdult diving beetles can be recognised bytheir streamlined shape and thin antennae.Both dorsal and ventral surfaces of the bodyare convex. Hind legs have paddle-like tarsibearing a dense fringe of swimming hairs.Adult beetles range from 2 to 35 mm long.

Distinguishing characteristics of larvaeLarvae are elongate with long legs coveredwith swimming hairs. They have largesickle-like mandibles that are almost alwaysdeeply grooved or perforated. Some larvaehave characteristic projections on theirheads. A pair of large spiracles is located at the tip of the abdomen. Many dytiscidlarvae have two tail filaments attached at the end of the abdomen.

Possible misidentificationsAdult dytiscids can be confused with otherbeetles having a streamlined body shape.Some hydrophilids have similar size andshape and their clubbed antennae, whichserve as a distinguishing character, are oftenheld under their head. Hydrophilids can bedistinguished by their flatter ventral surfaceand more convex dorsal surface comparedto most dytiscids. Adult dytiscids swim bymoving their hind legs simultaneouslysimilar to a breaststroke swimmer, buthydrophilids swim by moving their hindlegs alternately. When coming to the surfaceto renew their air supply, adult dytiscidspierce the water surface with the tip of theabdomen; hydrophilids use their antennae.

Diving beetles (Family: Dytiscidae)

The hind legs of a diving beetle are fringed withswimming hairs.

A 5 mm long Megaporus sp. moves swiftlythrough the water.

An 8 mm long dytiscid larva showing its large,piercing mandibles.

Some dytiscid larvae have characteristicprojections on their heads.

Beetles l 99

Dytiscid larvae can resemble hydrophilidlarvae but can be distinguished by havinglonger legs and serrated rather than smoothmandibles.

Classification and distributionDiving beetles are one of the most diversegroups of aquatic beetles with 226 species in42 genera recorded from Australia. Twenty-four genera are endemic. The familyDytiscidae is very common and occursthroughout the continent.

Three genera and at least 16 species live inunderground water bodies in the desertregion of Western Australia and centralAustralia. Many more species from thissubterranean habitat are waiting to bedescribed.

Habitat and ecologyDiving beetles inhabit a number of differentfreshwater habitats but are most likely to befound in ponds, lakes, billabongs, dams andshort-lived seasonally flowing streamswhere the water is stagnant or slow running.Adults often fly from one habitat to another.They use light reflected from the watersurface to detect a new habitat andsometimes confuse light reflected from glassor artificial light with water.

Both adult and larvae are voraciouspredators. They eat other aquatic

invertebrates and will sometimes attacksmall fish and tadpoles. Adult beetles havechewing mouthparts while most larvae havetheir mouth opening closed. They use theirhollow mandibles to inject digestiveenzymes into their prey and then suck outthe dissolved flesh.

Natural historyAdult beetles often deposit their eggs intoaquatic plants by making cuts in the stemusing their ovipositor. Larvae pupate out ofwater in damp soil and the adults return tothe aquatic environment.

Both larvae and adults use atmospheric airand come to the surface to renew theiroxygen supply. Adults store oxygen in abubble underneath the elytra while larvaeuse a siphon located at the tip of theabdomen.

This 4 mm long Necterostoma. sp is resting.

A dytiscid larva feeding on a small midge larva.

Rhantus suturalis replenishes its air supply.


Distinguishing characteristics of adultsAdult riffle beetles are small and darklycoloured with relatively long legs in relationto their body. Body size ranges between 0.9and 6 mm.

Distinguishing characteristics of larvaeLarvae are elongate and hard-bodied. Theirbody is semi-circular in cross-section withcolours from yellow to dark brown. The lastabdominal segment bears tufts of thread-like gills. These can be exposed to the watercurrent or covered by a flap (operculum)located underneath the last segment.Mature larvae are 2–6 mm long.

Possible misidentificationsElmid larvae can be confused withptilodactylid larvae. These two families canbe separated by the ventral flap, which ispresent in elmids at the tip of the abdomenin contrast to the pair of lobes possessed byptilodactylids. Ptilodactylid larvae can be upto three times longer than elmid larvae andtheir body surface is shinier and smoother.It is also possible to confuse adult elmidswith small Hydrophilidae and Hydrochidae.However, Hydrochidae and Hydrophilidaeoccur only in stagnant or slow-movingwaters and while alive adults can be

distinguished by an air bubble underneaththeir bodies.

Classification and distributionTwo subfamilies of Elmidae known inAustralia are Elminae and Larinae. Elmidbeetles collected in the water are most likelyto belong to Elminae. Common in uplandstreams, the sub-family includes six genera:Graphelmis (one species in Qld, NT andNSW), Austrolimnius (53 described speciesthroughout Australia), Kingolus(11 described species, endemic to Australia),Notriolus (16 described species, endemic toAustralia), Simsonia (16 described species,endemic to Australia) and Coxelmis(3 described species, endemic to Australia).

Riffle beetles (Family: Elmidae)

An adult elmid Kingolus sp. is only 1.5 mm long.

An elmid beetle (Austrolimnius) with a silverlayer of air retained by plastron hairs.

Elmid larvae, such as Notriolus sp., often feedon submerged woody debris.

Beetles l 101

Adult Larinae beetles live on land whiletheir larvae live in the water. The sub-familyincludes four genera: Hydora (one speciesfound in New South Wales), Ovolara (twospecies in Queensland and New SouthWales), Stetholus (one species in Victoriaand New South Wales) and Potamophilinus(one species in the Nortern Territory).

Habitat and ecologyElmids are most likely to occur in well-oxygenated upland streams on submergedwood or on rocks in riffles (hence the name:riffle beetles). Both adults and larvae feedon decaying vegetation and algae. Elmidbeetles sometimes bore grooves in sub-merged logs. These grooves are significantto the ecology of submerged wood as theyincrease roughness of the wood surface andtherefore make it possible for otherinvertebrates to colonise this habitat.

Natural historyAfter hatching, larvae go through five toseven instars. Last instar larvae develop a

series of spiracles on the sides of the body,which allow them to emerge from thewater and survive in damp areas close tothe stream before pupating.

In Australia, adult beetles return to water without taking flight, shortly afterthey emerge from the pupal stage.Both larvae and adults crawl onsubmerged substratum and are unable to actively swim.

Living in swift waters and being crawlersrather than swimmers, means that rifflebeetles do not have the luxury of coming to the surface to renew their air supply.Instead, larvae breathe using gills whileadults breathe by means of a plastron, athin film of air held by many microscopichairs. The plastron enables diffusion ofdissolved oxygen from the water, whichcan then be used for respiration.However, the use of a plastron restrictsElmidae to flowing waters with highconcentrations of oxygen.

Adults of Notriolus, around 4 mm long, often have four light spots on their backs.


Distinguishing characteristics of adultsAdult whirligig beetles have a streamlinedbody shape, are glossy black, and have theireyes divided into upper and lower portions.Their antennae are very short, and theirfront legs are much longer than the hindlegs, which are broad and paddle-like. Bodysize ranges from 4 to 18 mm.

Distinguishing characteristics of larvaeLarvae are elongate, with a pair of lateralfeathery gills on abdominal segments 1 to 8and two pairs of feathery gills on abdominalsegment 9. The last abdominal segment hastwo pairs of hooks. Their mandibles areenlarged and sickle-like.

Possible misidentificationsBoth the adult and the larva are verydistinctive. Adults can be separated from theDytiscidae and Hydrophilidae by havinglong front legs and short mid and hind legs.Larvae might be confused with larvae ofBerosus sp. (Hydrophilidae) and someMegaloptera larvae which also have lateralgills at the side of the body. Gyrinid larvaehave 10 pairs of feather gills which are much shorter than the length of the bodycompared to Berosus larva with seven pairsof tube-like gills, which often exceed thelength of the body.

Classification and distributionThe family Gyrinidae contains four generain Australia: Aulonogyrus, Dineutus, Gyrinusand Macrogyrus. Nineteen species have beendescribed from all states and territories.

Habitat and ecologyWhirligig beetles live in both still and run-ning water. Adults can often be seen cruisingon the water surface in small circles—hencetheir name—and forming large swarms ofseveral dozen individuals. Larvae inhabit thebottom of streams or ponds.

Adults feed on small organisms that fall onthe water surface, or scavenge on deadinvertebrates. Larvae are active predators.

Whirligig beetles (Family: Gyrinidae)

Gyrinid larvae have feathery gills and two hookson the last abdominal segment.

When threatened, whirligig beetles quickly divebelow the water surface.

Gyrinid larvae inhabit the bottom of streams orponds.

Distinguishing characteristics of adultsThese are small convex oval beetles withthin antennae. Enlarged coxal plates coverthe bases of their hind legs. The scutellum isabsent. The elytra are covered in a series ofpunctures and commonly have dark stripesor blotches. Body size 2.5 to 3.6 mm.

Distinguishing characteristics of larvaeLarvae are long and narrow with two pointyprocesses on each abdominal segment and along tail on the last abdominal segment.

Possible misidentificationsAdults can be mistaken for Hydrophilidae orDytiscidae. The best distinguishing featuresare the large coxal plates covering the bases ofthe hind legs, the thin antennae, the convexbody form and the absence of a scutellum.

Classification and distributionThe family Haliplidae is represented inAustralia by a single genus Halipluscontaining fifteen species. The family occurs throughout Australia.

Beetles l 103

Natural historyLittle is known about the lifecycle ofAustralian whirligigs. In North America, thebeetles copulate on the water surface and thefemale lays her eggs on the stems of emergentvegetation a few centimetres below thesurface of the water. After hatching larvaepass through 2–3 instars. They pupate onland either in holes dug into damp earth orcells constructed by the larvae above groundusing small pellets of mud.

Whirligig beetles have several remarkableadaptations. The most noticeable is theseparation of their eyes into upper andlower pairs. As they spend most of theirtime on the boundary between the air andthe water they need to keep an eye on what

is happening above and below. In case ofdanger they can quickly dive below thewater surface.

To detect small ripples generated by falleninsects, adult beetles are equipped with whatis called Johnston’s organ—a sensitive organlocated on their antennae.

Adult gyrinids can swim very fast on thewater surface as they secrete a surfactant thatreduces the surface tension of the water, andthus the friction between them and the water.

Adults breathe atmospheric oxygen whilelarvae use lateral gills to breathe underwater. The last larval instar developsfunctional spiracles and is capable ofbreathing atmospheric air.

Crawling water beetles (Family: Haliplidae)

Haliplids are convex beetles with a series ofstripes on their back.

The bases of the hind legs of haliplids arecovered by coxal plates.

An adult Hydraena sp. has small antennaeconcealed in grooves beneath its head andrelatively long maxillary palps, which can bemistaken for antennae.


Habitat and ecologyHaliplids are found among aquaticvegetation in ponds, lakes and streambackwaters. Adults feed on green algae.The larvae feed on other plant material.

Natural historyLittle is known about the lifecycle of haliplidsin Australia. In the northern hemispherelarvae pass through three instars beforepupation on land. Although the legs of theadults are equipped with swimming hairsthey are slow swimmers. When haliplidsswim they use alternate leg movements butmost often they crawl among vegetation.Larvae breathe oxygen dissolved in the water.

Distinguishing characteristics of adultsThese are small beetles between 0.8 and 2.5mm long. Adults of the genus Hydraenahave small antennae concealed in groovesbeneath the head and relatively long maxillarypalps. Adults of the genera Ochthebius andTympanogaster have normal size maxillarypalps but possess characteristic lateral plateson their pronotum. Adults can often be seencrawling upside down just under the watersurface with a reflecting bubble of air on theventral side of their abdomen.

Distinguishing characteristics of larvaeLarvae are rarely found in aquatic samplesand are likely to be marginal. The larvae of Tympanogaster live in the splash zones of waterfalls.

Possible misidentificationsHydraenid adults can be mistaken forHydrochidae and some Hydrophilidae.Long maxillary palps or lateral thoracicplates, along with their small size, help toseparate them.

Haliplid larvae live among aquatic vegetationand have a distinctive tail.

Family: Hydraenidae

Hydraena sp. can often be seen crawling upsidedown just under the water surface with areflecting bubble of air on the ventral side of itsabdomen.

Beetles l 105

Classification and distributionEight genera and 57 species have beendescribed in Australia. The most commongenera in south-eastern Australia areHydraena and Ochthebius. The familyoccurs throughout the continent.

Habitat and ecologyHydraenids live in a wide variety of habitatsincluding streams, waterfalls, ponds, ditches,marine rock pools and inland salt lakes.They are most likely to be found in stagnantwaters among aquatic vegetation and at thewater edge. Little is known about the habitatand ecology of the larvae and most areprobably terrestrial or semiaquatic.However, larvae of Tympanogaster living in the splash zone use tiny spiracular tubesto breathe under water. Hydraenids feed on algae.

Natural historyLittle is known about the lifecycle ofhydraenids in Australia. In the northern

hemisphere hydraenids lay eggs on woodand stones just beneath the waterline.Newly hatched larvae leave the water andlive in the littoral zone.

Adults breathe under water using a plastronbut are capable of renewing their oxygensupply with atmospheric air.

Adults and a larva of the genus Tympanogaster living in the splash zone of a waterfall.

An adult Ochthebius sp. showing the lateralplates on its pronotum and its shiny bodysurface.


These two families are close relatives andHydrochidae is sometimes regarded as agroup within Hydrophilidae.

Distinguishing characteristics of adultsMost adults are recognised by their 7- to 9-segmented antennae with a 3-segmentedclub. The hind legs of many but not alladults have swimming hairs. A scutellum isalways present at the base of the elytra.

Distinguishing characteristics of larvaeHydrophilid larvae are variable. They havelarge serrated mandibles and theirabdomens usually have a wrinkledappearance, with or without filaments onthe side. Hydrochid larvae have not beenfound in the water.

Possible misidentificationsOften the antennae are tucked beneath thehead and the long maxillary palps may bemistaken for antennae. The hydrochids areclose relatives of the hydrophilids and adultsfrom the two families look very similar.Hydrochid adults can be recognised becausetheir pronotum is narrower than theirelytra, and their body is covered with strongindentations. Hydrophilid adults have asmooth bubble-like form. Hydrophilidadults and larvae can also be confused withdiving beetles (see page 98).

Classification and distributionNineteen genera of aquatic hydrophilids arerecorded in Australia. The most commongenera in south-eastern Australia areBerosus, Helochares, Enochrus and

Water scavenger beetles (Families: Hydrophilidae and Hydrochidae)

This adult Anacaena sp. is only 2 mm long.

A hydrochid adult can be recognised by thepronotum being narrower than the elytra and byits body covered with strong indentations.

Adult Berosus beetles use their maxillary palps as sensory organs while underwater. Their antennaefulfil the same function on dry land.

Beetles l 107

Limnoxenus. The Hydrochidae includes a single genus Hydrochus which has a worldwide distribution with around 27recognisable species found in Australia.

Habitat and ecologyHydrophilids are most often found instagnant and slow-moving waters. Theirtypical habitats are wetlands, ponds, dams,and streams with slow current and plenty ofaquatic plants. Most hydrophilid larvae arepredacious. Adults are largely herbivorousbut may scavenge on dead insects and othersmall animals.

Adult hydrochids are found in a wide rangeof habitats, most often in stagnant or slowlyflowing waters, at the banks of rivers,billabongs and ponds. They are herbivorous,feeding on detritus, parts of plants andperiphyton.

Natural historyAdults of some genera (e.g. Berosus) makecharacteristic stridulations under water orwhen captured. Females of some generacarry their eggs underneath the abdomen.

Both adults and larvae breathe atmosphericair. Adults store an air bubble underneaththe abdomen and between the elytra andabdomen which gives them sometimes asilvery appearance. Most hydrophilid larvaebreathe through two large spiracles at thetip of the abdomen. Some hydrophilids (e.g. Berosus) have a breathing siphon andlarge serrated mandibles. They are poorswimmers and prefer to crawl on aquaticplants, pieces of wood etc. while they movearound and search for their prey.Hydrochids can’t swim and instead crawlaround on water plants, submerged woodand other surfaces.

Larval Berosus have long filaments along theirsides.

A female Helochares carrying eggs under herabdomen.

A large hydrophilid larva showing the well-sclerotised head and serrated mandibles.


Distinguishing characteristics of adultsHygrobiid adults are stout beetles around 10 mm long, with bulging eyes and withoutthe smooth outline of diving beetles. Theyusually crawl but can swim using alternatingleg movements.

Distinguishing characteristics of larvaeLarvae are well sclerotised and rounded,with feather-like abdominal gills and a longtube-like extension to the abdomen which,with two long filaments, results in a distinc-tive, three-pronged end to the abdomen.

Possible misidentificationsAdults and larvae can be confused withhydrophilids or dytiscids. Adult hygrobiidscan be separated by their bulging eyes.Hygrobiid larvae are unusual in havingfeather-like gills underneath their abdomen.They also have three filaments at the tip ofthe abdomen while most dytiscid larvaehave only two or none.

Classification and distributionThe family Hygrobiidae includes a singlegenus, Hygrobia. Two species occur insouth-eastern Australia, one species inNorth Queensland and the Northern

Territory and one in the south-west.Two other species are found in Europe,North Africa and China.

Habitat and ecologyScreech beetles occur in stagnant muddywaters of dams, ponds and wetlands. Theyare predators on other invertebrates.

Natural historyUnlike dytscids and hydrophilids, hygrobiidlarvae possess gills at the base of their legsand underneath the first three segments ofthe abdomen. These possibly compensatefor the fact that dissolved oxygen can’t reallydisperse through their skin.

Screech beetles (Family: Hygrobiidae)

A larva of Hygrobia sp. with its characteristicthree-pronged tip of the abdomen.

Adult screech beetles look a bit like goggle-eyed diving beetles.

Beetles l 109

Distinguishing characteristics of adultsAdults are terrestrial. They are broad,somewhat flattened and dark coloured.They have a distinctively serrated joinbetween their pronotum and elytra.

Distinguishing characteristics of larvaeLarvae are distinctly flattened and disc-like,oval or sometimes round. Side extensions ofevery segment form a shield, whichcompletely covers the head and legs of theanimal from above. The body shape of thelarvae resembles that of trilobites.

Possible misidentificationsIt is almost impossible to confuse psephenidlarvae with any other family.

Classification and distributionA single genus Sclerocyphon with 13described and 5 undescribed speciesrepresents this family in Australia. Thefamily is widespread throughout the world.

Habitat and ecologyLarvae are commonly found in stronglyflowing or turbulent sections of a stream,but can survive in stagnant water if it is welloxygenated. Most often they are attached torocks or large logs. Larvae are strictlybenthic and feed on periphyton and otherplant material covering the stream bed.

Natural historyLarvae spend from 12 to 22 months in thewater. The adults live around two months.The mature larva leaves the water to pupatein the litter and soil of the river bank. Whenthe larva is out of the water it can breatheatmospheric oxygen using a pair of spiraclescovered by brushes on the last abdominalsegment. Adults live in vegetation near thestream edge. Females crawl down the sidesof emergent rocks to lay their eggs under the water. Unlike many other beetle larvae,they breathe oxygen dissolved in the water.They use their retractable gills at the tip oftheir abdomen, which they wave around toincrease oxygen absorption. The larval bodyshape is ideal for clinging to rocks andminimising water resistance.

Water pennies (Family: Psephenidae)

Adult water pennies are broad, flattened anddark coloured.

One needs to look from underneath to see apsephenid larva’s legs and head.

The body shape of a psephenid larva resemblesthat of a trilobite.


Distinguishing characteristics of adultsAdult ptilodactylids are terrestrial. They areelongated, hairy beetles with striated elytraand antennae longer than half the bodylength.

Distinguishing characteristics of larvaeLarvae are elongated and sub-cylindrical incross-section. They are hard-bodied andpale brown in colour. The mostdistinguishing feature of the larva is a pairof lobes with hooks at the posterior tip ofthe abdomen.

Possible misidentificationsSee Elmidae.

Classification and DistributionAustralian ptilodactylid beetles, bothterrestrial and aquatic, include 15 describedspecies. All aquatic species belong to thegenus Byrrocryptus which occurs along theeast coast of mainland Australia.

Habitat and ecologyLarvae live in running water and feed ondecaying plant material including wood.

Natural historyVery little is known about the lifecycle of theAustralian Ptilodactylidae.

Family: Ptilodactylidae

Marsh beetles (Family: Scirtidae)

A larva of Byrrocryptus sp. The tip of itsabdomen has a pair of lobes with hooks.

Distinguishing characteristics of adultsAdult marsh beetles are terrestrial. Theyhave a round, flattened body and are up to11 mm long.

Distinguishing characteristics of larvaeLarvae are elongate, flattened, and range insize from 5 to15 mm long. The segments are

sclerotised but the larvae look soft andflexible. Their most distinguishing feature istheir multi-segmented antennae, which arelonger than the combined length of thehead and the first thoracic segment. Theiroverall appearance resembles that of ajuvenile cockroach.

Beetles l 111

Possible misidentificationsMarsh beetle larvae are easilydistinguishable by their antennae, and arenot likely to be confused with any otheraquatic beetle larvae.

Classification and distributionSix genera and more than 50 species areknown from Australia. The more commongenera are Scirtes, Cyphon and Prionocyphon.

Habitat and ecologyAs their name implies, most marsh beetlelarvae live in marshes, wetlands, ponds, dams,and streams with slow current and plenty ofaquatic plants. Sometimes they are found

along the edges of faster flowing streams.They feed on detritus, filtering it from thesurface of leaves and stones using theircomplex comb-like mouthparts. Theybreathe atmospheric air through the tip ofthe abdomen and therefore have to come tothe surface for air from time to time. Oftenthey are seen crawling upside down on theunderside of the water surface.

Natural historyLittle is known about the life history ofAustralian marsh beetles. They produce onegeneration a year in temperate Australia.Larvae pupate among dead leaves or in mudchambers or cells on land.

A marsh beetle larva with its characteristically long antennae.


CHIRONOMID LARVA

CHIRONOMID ADULT SCIOMYZID ADULT

SCIOMYZID LARVA

halteres

mouth hooks

spiracles

head capsule

eyespots

antennae

mentum

hooked anterior pro-legs

hooked posteriorpro-legssetae

halteres

welts

Flies, true flies (Order: Diptera)

The dipterans are a very diverse group of insects that occur in most, if not all of theinland waters of temperate Australia. They can be found in a range of environmentalconditions, thriving in septic tanks and wilderness areas alike.

The larvae of midges (Chironomidae) and marsh flies (Sciomyzidae) provide the two extremes ofbody structure between which most dipterans will fit.

Flies l 113

Characteristics of an adult flyAdult flies have large compound eyes and asingle pair of wings. Most of the otherinsects dealt with in this book have twopairs of wings: one on the mesothorax andthe other on the metathorax. Flies havereduced their second set of wings to a pairof small knobs (halteres) and these aid inbalance during flight. Diptera translatesfrom the Greek as ‘two-winged’ (di = two,ptera = wings).

A diverse range of adult flies can be foundnear fresh water. Some of these skate on the water surface, where they scavenge orprey on dead or dying insects—a similar lifeto the water striders (Hemiptera). Otherscan be found in swarms above water, orclinging to vegetation and rocks nearby.The adults are usually agile fliers, capable oftravelling long distances and this helps makemany of these insects widespread if notcommon.

Clytocosmus (Tipulidae) is one of the larger,more brightly coloured dipterans.

Adult male chironomids have highly sensitiveantennae that they use when finding females.

Fly spotting

While it is almost impossible to identify most adult flies while they are alive, some ofthe commoner families can be recognised by the following characters:

crane flies (Tipulidae): very long legs; slow cumbersome flight, long abdomens

black flies (Simuliidae): small, black, with rounded wings and fat little bodies

non-biting midges (Chironomidae): small delicate flies; males have fluffy antennae;unlike mosquitoes they keep their front legs (rather than their middle ones) in the air when resting

mosquitoes (Culicidae): slender bodies, fine wings and long piercing mouthparts;second pair of legs raised when resting

hover flies (Syrphidae): often orange/cream and black (wasp mimics) with hoveringflight

horse flies (Tabanidae): large eyes (almost touching); robust bodies; piercingmouthparts

marsh flies (Sciomyzidae): some of the commoner swamp genera have spotty wingsand a streamlined body


Key to the common families of aquatic dipteran larvae

1 stocky larvae with 6 wide body segments and a row of suction cups on theirunderside . . . . . . . . . . . . . . . . bleffs or net-winged midges (Blephariceridae, p. 118)

1 not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2(1) elongate pear-shaped larvae with a hook-lined suction cup at one end, and feathery mouthparts at the other . . . . . . . . . . . . . . . . . . . . . . . . . . . black flies (Simuliidae, p. 129)

2 larvae not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3(2) larvae with most segments sclerotised: either totally or only on the dorsal surface . . . . . . . . . . . . .moth flies and soldier flies (Psychodidae and Stratiomyidae, p. 128)

3 larvae not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) larvae with many stiff erect hairs, final segments heavily sclerotised . . . . . . . . . . . . . . 54 larvae without many stiff erect hairs and without a heavily sclerotised final

segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5(4) larvae transparent or bent like a ‘U’ and final segment with three lobes, the central one with tufts of hair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .‘U’ bent larvae or meniscus midges and phantom midges

(Dixidae and Chaoboridae, p. 123)5 larvae not as above . . . . . . . . . . . . . . . . . . . . mosquitoes, wrigglers (Culicidae, p. 122)

6(4) larvae with a sclerotised head capsule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 larvae without a sclerotised head capsule, head retractable into thorax . . . . . . . . . 12

7 larvae without any pro-legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87(6) larvae with pro-legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8(7) hind end of larvae with hairs, but without fleshy projections, head not retractable into thorax . . . . . . . . . pogs, biting midges or sand flies (Ceratopogonidae, p. 119)

8 hind end of larvae with fleshy projections and sometimes hairs, head retractable into thorax . . . . . . . . . . . . . . . . . . . . some tipulids: dollies, march flies and crane flies

(Dolichopodidae, Tabanidae and Tipulidae, p. 124)

9(7) larvae with paired fore and hind pro-legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 larvae either without front pro-legs, or with single pro-legs . . . . . . . . . . . . . . . . . . . . . . 11

10(9) most body segments with spines or processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Forcipomyiinae: pogs, biting midges or sand flies (Ceratopogonidae, p. 119)

10 most body segments without spines or processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . non-biting midges, ‘mids (Chironomidae, p. 120)

11(9) larvae either with a single front pro-leg, or with long fleshy projections on the final segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

11 larvae without front pro-legs, or fleshy projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dasyheleinae: pogs, biting midges or sand flies (Ceratopogonidae, p. 119)

12(6) larvae with 7-8 pairs of well developed hooked pro-legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Athericidae and Empididae (p. 116)

12 larvae without 7-8 pairs of hooked pro-legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

13(12) larvae long and parallel-sided with rounded ends, often worm-like in appearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dollies, march flies and crane flies

(Dolichopodidae, Tabanidae and Tipulidae, p. 124)13 larvae taper towards the front, maggot-like in appearance . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . ephydrids, muscids, marsh flies and rat-tailed maggots(Ephydridae, Muscidae, Sciomyzidae and Syrphidae, p. 126)

Flies l 115

Characteristics of a larval flyFly larvae vary considerably in their bodystructure. Chironomids and sciomyzidsprovide the two extremes of body structurebetween which most dipteran larvae will fit.Chironomid larvae are elongate, withdistinct pro-legs and a head capsule, whilethe sciomyzid larvae are maggot-like. Somedipteran larvae have well-developed headcapsules with eyespots, while others aremaggot-like with soft ‘heads’ and only theirinternal mouthparts hardened. Many havepro-legs and these can be quite large (as inthe midges/chironomids) ending in lots ofhooks, or they can be broad stumpystructures that are more like raised welts (asin the empidids). None of them have jointedlegs, none of them have wing buds and veryfew have sclerotised thoracic segments.

ClassificationThe 20 families with aquatic larvae that aredealt with in this book include some of thegreatest diversity within the Diptera. TheChironomidae and the Culicidae are eachrepresented by more than 200 speciesAustralia-wide and the Tipulidae by around700 species (though many of these areterrestrial). Other families are less diverse,but the taxonomy of the aquatic families isstill far from complete and many newspecies are likely to be discovered as researchinto their ecology and biology progresses.

The key on these pages is a rough guide tofamily, or groups of families where theanimals are more difficult to distinguish.Care should be taken with the less commonlarvae such as the Tanyderidae, as they

closely resemble other more commonanimals. Fleshy dipteran larvae can oftenretract parts of their bodies such as heads,spiracles and pro-legs and this can makesome individuals very difficult to identify.

Key to the common families of aquatic dipteran larvae (contd.)

Larval tipulids are soft-bodied maggots with apair of posterior spiracles surrounded by fleshyprojections. Most are not as spectacular as theregal maggot Clytocosmus.

Larval tanypods (left) are predators, whilesimuliids (right) are filter feeders. Both havesimple bodies with head capsules and eyespots.

14(11) larvae with long fleshy projections on the final segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tanyderidae (p. 130)

14 larvae with a single front pro-leg; without long fleshy projections on the final segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thaumaleidae (p. 130)


Maggots and the fast lifeMany aquatic fly larvae have short lives,which allows them to grow in temporarywater in ponds and puddles. They also havesimple bodies so they can make the most offood when it is available. Their simple larvalbody works a bit like an elastic-sidedgarbage bag and can stretch toaccommodate a large meal better than acomplicated nymph-like body can. Theseopportunistic characteristics allow some flyspecies to complete five or six lifecycles in ayear. The shortest recorded larval stage isunder two weeks, with adults maturingalmost immediately after emergence.

Adult flies can lay hundreds of eggs andrarely live for longer than a month(regardless of the length of the larval life).This makes the shortest dipteran lifecycle,from egg to egg-laying, a little over twoweeks. Some of the fastest living Diptera arefrom the family Chironomidae.

Environmental significanceThe extreme variability of dipterans extendsto their tolerance of pollution. Some of thehardiest animals, such as the rat-tailedmaggots (Syrphidae) actually preferorganically polluted sites and thrive insewage and carrion. At the other extreme,the tanyderids are restricted to coldmountain streams with a healthy supply ofwood and leaf litter and are intolerant ofmost pollutants.

Diverse and well-studied families such asthe non-biting midges (Chironomidae) canprovide much information about theirsurrounding environment. Different speciesare often indicative of differentenvironmental conditions such as waterchemistry. Sometimes these changes alsoindicate environmental impacts. In extremecases of pollution, the deformities of themore tolerant species can be studied toassess environmental impacts.

Distinguishing characteristics Athericid larvae have fleshy bodies, nosclerotised segments, paired pro-legs onabdominal segments 1–7 and a single leg on segment 8. Empidid larvae have pairedpro-legs on abdominal segments 1–7 andeither no pro-legs or two pro-legs onsegment 8. Athericids have distinct fleshyprojections along the sides of their bodies,but empidids don’t. Both feed using a pairof sclerotised hook-like mouthparts thatretract into the front of their body.Athericid larvae grow to around 10 mm,while aquatic empidid larvae are usuallysmaller (3–5 mm), but can reach the samesize. Adult athericids are stocky little flies a bit like black flies (Simuliidae), but theyaren’t commonly encountered. Empididadults are more common and are

sometimes called ‘dance flies’ because theyspend their time moving rapidly over thewater surface looking for prey. They have adistinctive ‘beak’ for piercing prey.

Families: Athericidae and Empididae

Larval empidids, as with all maggot-like flylarvae, can alter their length and are usuallymore truncate than this.

Flies l 117

Possible misidentificationsSome ephydrids (page 126) may resembleathericids, but ephydrid larvae never havefleshy projections along their sides.

Classification and distributionThe Athericidae was previously consideredpart of the Rhagionidae. One genus ofathericid (Dasyomma) is known fromsouthern Australia and also occurs in SouthAmerica. The 11 Australian species withinthis genus can only be identified as adults.The Empididae is a large family; many of itsrepresentatives are terrestrial.

Habitat and ecologyLarval athericids and empidids are predators,feeding on a range of smaller invertebrates.Their hook-covered pro-legs give them asolid purchase in faster-flowing waters andtheir flexible bodies allow them to traveleasily through the gravel in riverbeds. Someadult athericids are thought to feed onblood but don’t seem to bother humans.

Natural historyIn the northern hemisphere, larvalathericids leave the water to pupate andadults are thought to lay their eggs onfoliage that overhangs a stream. This allowsthe newly hatched larvae to drop straightinto the water. It is likely that Australianathericids behave similarly.

Adult empidids use their piercing mouthparts toprey on other insects trapped on the watersurface.

Larval athericids have a distinctive set of lateral projections, and a pair of longer terminal ones.They move by stretching and contracting their bodies.


Bleffs or net-winged midges (Family: Blephariceridae)

Distinguishing characteristics Bleff larvae have their bodies divided intosix broad lobes, each with a suction cup onthe ventral side. The head is set into the frontsegment and adorned with short antennae.Larvae move sideways when they aredisturbed. This motion involves detachingthe front suckers, flexing sideways and re-attaching them. This movement is repeatedwith the hind suckers and propels theanimal swiftly but comically sideways.In fast-flowing water, larvae progress slowlyby detaching individual suckers and movingthem forward. Larvae can grow to 13 mm.Adults are relatively slender and easilydistinguished by the creased look of theirwings and the fact that they generally hangfrom their front two legs near water.

Classification and distributionFour genera and around 27 species ofblepharicerid are found in south-easternAustralia. Edwardsina is the commonestgenus (and the only one found in Tasmania),whereas three other genera (Apistomyia,Austrocuripira and Parapistomyia) are alsofound in New South Wales, Victoria and theAustralian Capital Territory. The northerngenera are thought to be strongly linked tofauna in the tropics, while Edwardsinaseems to be a Gondwanan relic.

Habitat and ecologyBleffs graze the fine layer of periphyton(mainly algae) on the surface of rocks in thestream. Their suction-cup-coveredundersides allow them to cling to rocks invery fast-flowing water.

Natural historyBleffs are good indicators of a number ofdifferent human impacts. They prefer rocksin fast-flowing water, so they are sensitive tounseasonal changes in flow conditionsbrought about by dams and irrigation.They also seem to avoid the larger algae thattend to accumulate in nutrient-rich waters.This combination of characters restrictsthem to fairly pristine, fast-flowing waters.

Bleffs have an instantly recognisable bodyshape.

Adult bleffs hang by their front legs from theundersides of branches and rocks along thesides of the stream.

The underside of a bleff has a row of suctioncups which allow it to stick to rocks in placeswhere no other invertebrates can venture.

Flies l 119

Pogs, biting midges or sand flies (Family: Ceratopogonidae)

Distinguishing characteristics Pogs are a diverse group, with four verydifferent body shapes, belonging to the fourdifferent subfamilies. The commonest form(Ceratopogoninae) is very long and thinand moves with a fast, stiff, snake-likemotion. They have a bullet-shaped head anda rosette of hairs on their final segment.Most pogs are under 20 mm long. Theadults are slightly stockier than chironomidsand have long antennae.

Possible misidentificationsThe Dasyheleinae can be easily confusedwith chironomids or thaumaleids, thoughthey differ by lacking a front pair of pro-legs.The Forcipomyiinae can also resemble theThaumaleidae. Forcipomyiinae have a frontpair of pro-legs, but they are usually coveredwith spines or processes and lack the smallsclerotised breathing tube that thaumeleidshave on their first thoracic segment.

Classification and distributionFour subfamilies of Ceratopogonidae occurin Australia: Ceratopogoninae, Dasyheleinae,Forcipomyiinae and Leptoconopinae.Although there are more than 100 species insouth-eastern Australia, all four subfamiliesare more diversely represented in northernAustralia. Pogs occur worldwide.

Habitat and ecologyMost members of the Leptoconopinaeburrow in the sandy edges of rivers andestuaries. These are the unloved ‘sand flies’.The Ceratopogoninae has members thatoccur commonly in streams, though usuallyin slower flowing sections or in the mud atthe edges. The Dasyheleinae andForcipomyiinae are much less common andare thought to occur in disconnectedaquatic and semi-terrestrial habitats.Both of these groups tend to occur instream samples after heavy rains, suggestingthey are washed in from the puddles andwater-filled tree hollows that they normallyinhabit.

Pogs have thin, fast-moving bodies with aconical head capsule at one end and a rosetteof hairs at the other.

Pogs from the subfamily Dasyheleinaesuperficially resemble chironomids, but theylack front pro-legs.

The ceratopogonid subfamily Forcipomyiinaecontains some peculiar animals. Most havespines, or projections along their sides.


Non-biting midges, ’mids (Family: Chironomidae)

Distinguishing characteristics

Chironomid larvae are long, with fleshybodies and sclerotised head capsules. Theyusually have a pair of fleshy pro-legs on thefirst segment after the head and anotherpair on the final segment. Both are armedwith small hooks. Chironomids move inopen water by rapidly coiling and uncoilingtheir bodies. This gives them a hecticthrashing appearance. They move morecalmly over rocks and plants, using aninchworm-like gait. Most chironomids areless than 10 mm long.

Possible misidentificationsThe Thaumaleidae and the Dasyheleinae(Ceratopogonidae) can both be mistakenfor chironomids. The reverse is also possible.Both the Thaumaleidae and the Dasyheleinaeare comparatively rare, however, andrestricted to odd habitats. Two genera ofchironomid (Harrisius and Stenochironomus)are superficially similar to tanyderids.Tanyderids differ by having more long fleshyprocesses attached to both the last andsecond last segments. The two chironomidshave them on the last segment only.

Classification and distributionThe freshwater chironomids of temperateAustralia can be split into six subfamilies.The Chironominae, Tanypodinae andOrthocladiinae are common and diverse,while the Diamesinae, Aphroteniinae andPodonominae are represented by two orthree genera each. The three commonsubfamilies are found in most rivers andlakes, while the remaining three tend tooccur at higher altitudes, or in colder waters.This possibly explains why the latter are morecommon in Tasmania than on the mainland.

Many of the Chironominae are red, but thecommonest genus in urban and rural sites isChironomus.

The three most common subfamilies ofchironomids: Tanypodinae (top, with large heads),Chironominae (bottom right, with double eyespots) and Orthocladiinae (bottom left).

The less common subfamilies of chironomids:Diamesinae (left with the dark collar),Aphroteniinae (middle) and Podonominae (right).

Flies l 121

Habitat and ecologySome members of the subfamilyChironominae are simple detritivoresfeeding on a mixture of algae and bacteriain soft sediments. This subfamily alsoincludes filter feeders that build tubesadorned with a simple radial net, as well as a number of wood-boring species. Most ofthe Orthocladiinae are algal grazers, butsome are predators or parasites and thereare a few wood-boring species. All of theTanypodinae are thought to be predators,though some may feed on algae and bacteriain their early larval stages. MostAphroteniinae live and feed amongst fineorganic matter in cold upland streams, butthere are some recorded from sea level lakesin southern Western Australia. TheDiamesinae and Podonominae feed on algaeand bacteria, usually scraping it from thesurface of rocks and wood. Diamesinae aretypically found in thin-film waterfalls.

Natural historySome of the Chironominae have distinctivecharacteristics that allow them to be

identified to genus quite easily. Bloodworms(Chironomus) are typical of organicallypolluted waters. They breathe dissolvedoxygen using a very efficient blood pigment,which is similar to our own and gives themtheir distinctive red colouring.Rheotanytarsus builds a tube fringed with anet in flowing waters, while Stempellina andZavreliella construct portable, sand-coveredcases a bit like those used by caddis flies.

Rheotanytarsus larvae build nets around their tubes to catch food from the water as it flows past.The net is hung between the five struts that stick out from the edge of the tube.

A mating pair of chironomids. The male is theone with the elaborate antennae.


Mosquitoes, wrigglers (Family: Culicidae)

Distinguishing characteristics Larval mosquitoes have elongate, bristle-covered bodies. The first three segmentsbehind the head are slightly wider than theabdomen. The abdomen ends in asclerotised set of segments including asiphon (except in the Anophelinae) and asclerotised and hair-covered last segment.Their heads are quite large and the mouth-parts usually involve a set of brushes thatare used for sweeping microalgae into themouth. Adults have distinctively longmouthparts, with which the females ofsome species will extract blood frommammals, but which most individuals usefor drinking water and nectar.

Possible misidentificationsDixid and chaoborid larvae are similarlooking, but the first three thoracicsegments aren’t widened in the dixids andthe chaoborids are fairly rare and quitetransparent. Chaoborids have air sacs within their thorax and abdomen enablingthem to float horizontally, while mostmosquito larvae float with their headshanging down. Mosquito larvae from thesubfamily Anophelinae float horizontallybut are well pigmented.

Classification and distributionTwo widespread subfamilies of mosquitoare found in temperate Australia. TheCulicinae are represented by around sixgenera and 70 species. The Anophelinae isless diverse with a single genus and fewerthan 10 species. Species from these groupsoccur worldwide and the temperateAustralian fauna has links with species inNew Zealand, South America and Asia.

Habitat and ecologyMost mosquito larvae feed on microalgae,which they filter from the water with theirhair-covered mouthparts. These feathery

appendages create a current that pulls infood. Some mosquito larvae are predatorsand in many cases prey upon smallermosquito larvae. All mosquito larvae arerestricted to stagnant or slow-flowing water.

Natural historyMosquito larvae must return to the surfaceevery now and then to replenish their airsupply. Often they will float with theirsnorkel-like siphons puncturing the watersurface and providing them with a constantsupply of fresh oxygen. When they pupate,mosquito larvae swap from a breathingsiphon attached to their abdomen, to a pairof breathing horns attached to their firstthoracic segment. This swap changes theorientation of the animal in the water from

Adult male mosquitoes do not take blood frommammals, but their needle-like mouthparts arejust as useful for feeding on fruit and nectar.

A pair of mosquito larvae hang from the surface,leisurely filtering the water with their brush-covered mouthparts.

Flies l 123

‘U’ bent larvae or meniscus midges and phantom midges(Families: Dixidae and Chaoboridae)

upside down, with the mouthparts danglingdown in the water for feeding, to upright,with the back of the pupa towards the watersurface. This allows the adult to breakthrough the pupal skin and struggle

through the water surface as it emerges.Mosquitoes are one of the few animalswhere both their common and taxonomicnames are Latin. Muscito means small fly,musca being Latin for fly.

Distinguishing characteristicsDixid larvae are long, thin surface-dwellinganimals. Their bodies are covered with stiffhairs and these help them stay on the watersurface while their heads are submerged.Their final segments are impressivelyornamented. When dixids move, they flextheir bodies into a distinct ‘U’ shape, andthis propels them along the water surface orover wet mud/rock equally well. Chaoboridsfloat mid-depth in still water, where they arepredators of small invertebrates such asmicrocrustaceans. They have transparentbodies, with the first segment after the headenlarged to contain two flotation sacs. Theirantennae are modified for shoveling smallprey into their mouths.

Possible misidentificationsSee Culicidae (page 122).

Classification and distributionTwo genera of dixid occur in south-easternAustralia: Dixella and Nothodixa, with sixspecies between them. Four genera and atleast six species of chaoborid are knownfrom south-eastern Australia, but none ofthese is common.

Ecology and natural historyThe dixids feed on planktonic algae, whichthey filter from just beneath the watersurface with brush-like mouthparts. Theyoccur in still waters such as small lakes, farmdams and on the edges of backwaters andpools. Larvae seem to be more comfortableholding onto vegetation or the mud of thebank, even though they are capable of

resurfacing if they sink and sometimes willdive under the water if threatened.Chaoborids are mainly planktonic predatorsin lakes or smaller still waters, such as damsor even tree hollows.

Dixids, like mosquito larvae, filter the water foralgae. The plates and hairs on the final segmentkeep water from covering the spiracles.

Phantom midges (Family: Chaoboridae) arealmost totally invisible to their prey. A pair of airsacs keep them floating horizontally.


Dollies, march flies and crane flies(Families: Dolichopodidae, Tabanidae and Tipulidae)

Distinguishing characteristics The larvae of all three families are elongateand parallel sided, with heads that can beretracted into their first body segments. TheTipulidae and Dolichopodidae both havefleshy projections on their hind ends andsome tipulids have these covered with hairs.Dolichopodids often have shorterprojections that are lobed and curved inwhen viewed from the side. The hind endsof the tabanids are comparatively simple, asthe spiracles are enclosed. All three familiescan have welts on their segments andsometimes these can include small hooks tohelp the larvae move. All three groups are

variable in size, but some tipulid/tabanidlarva can be longer than 30 mm. Adulttipulids are long-legged and sometimescalled ‘daddy long-legs’. Adult dolichopodidsare usually metallic green and are waterskimmers, while tabanids are march orhorse flies and are known for their size andtheir painful bite.

Possible misidentificationsSome members of the Tabanidae aren’tquite parallel sided, so it might be necessaryto look more closely at the spiracles, whichshould be enclosed beneath a vertical slit atthe hind end of the animal.

Tabanid larvae are predators that can move through the stream bed to search for prey. Adults usetheir piercing mouthparts to extract blood from mammals.

Dolichopodid larvae have a distinctive hind end, which allows them to be distinguished from theotherwise similar tipulids. The adults are metallic green, and have impressive raptorial tarsal claws.

Flies l 125

Classification and distributionAll three families are very diverse and widelydistributed. The Tipulidae are probably themost diverse, with around 700 speciesAustralia-wide.

Habitat and ecologyThe larvae from all three families in thisgroup are usually predatory. They arecommon inhabitants of fine sediments in

slow-flowing water, but they do also turn upin faster-flowing areas, and marginal orterrestrial environments.

Tipulid larvae can be quite variable. The animal on the left has a partial head capsule that can beretracted into its body, while the one on the right only has hardened mouthparts.

Adult tipulids are sometimes referred to as crane flies, or daddy long-legs for obvious reasons.


Distinguishing characteristics The larvae of these families are less elongatethan the previous group. Their bodiesnarrow gradually towards the front andtheir heads can be retracted into their firstbody segments. Syrphids can easily bedistinguished by their long, tail-like siphon.

Possible misidentificationsAll the maggot-like larvae are difficult toidentify; you will make mistakes (but don’tgive up!). Some of the muscids andephydrids have pro-legs, but they differfrom the athericids by not having lateralprojections. Empidids can be separatedbecause they lack spiracles; members ofthese four families usually have well-developed spiracles.

Classification and distributionAll of the families within this group are fairlydiverse and widespread. They also includespecies with terrestrial larvae. The familyMuscidae, for example, includes a numberof commonly encountered houseflies.

Habitat and ecologyEphydrids and syrphids are thought to grazeon microalgae. Both are typical of stillwaters and often occur in highly polluted orlow oxygen environments such as stagnant,nutrient-rich puddles. Sciomyzids arepredators on a range of molluscs in slow-moving or still waters. They are particularlyabundant in wetlands, or in dams wheretheir gastropod prey are present. Muscidsare very diverse and occur in slow and fast-

Ephydrids, muscids, marsh flies and rat-tailed maggots(Families: Ephydridae, Muscidae, Sciomyzidae and Syrphidae)

Sciomyzid larvae prey on small snails in damsand wetlands.

Adult sciomyzids have distinctively spotty wings,and are a common sight around wetlands.

The ephydrids are a common component of slow moving, stagnant and polluted watercommunities.

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flowing water, where they are usuallypredators of other fly larvae and worms.

Natural historySome North American ephydrids arefamous for their ability to survive in poolsof tar. So far this has not been recorded forAustralian species.

Sciomyzids are known as marsh flies, orsnail-killer maggots—a name that comesfrom their use as a biological control ofpond snails, especially those that arethought to be a vector of sheep liver flukes.Sciomyzid larvae can voluntarily inflatetheir bodies and sometimes use this to dragsnails from the pond bottom to the surface.

The ancient Greeks are said to havemistaken hover flies (Syrphidae) for beesand this led to a rather unsavoury ritual thatthey believed necessary to re-stock theirhives. Syrphid larvae thrive in puddles ofrotting carrion, so the ancients wouldbludgeon some livestock to death, then sealthem into the equivalent of a small shed.

The animals would rot and the syrphidlarvae or rat-tailed maggots would thrive in the putrid puddles. Later, when the shedswere opened, a swarm of ‘bees’ would burstfree. Syrphid larvae can survive in putridwater that lacks oxygen because they havean extendable snorkel that can stretch to the surface, even if it is several bodylengths away.

Syrphidae: the rat-tailed maggot (bottom) turnsinto a bee-like hover fly (top). The larva has asnorkel-like appendage which it uses to breathe.

Adult syrphids are a common sight in most gardens, as there are a number of terrestrial members inthis family.


Distinguishing characteristics The larvae of moth flies and soldier fliesdiffer from most other fly larvae by havinghardened plates on their bodies. Thesecover the entire body of soldier fly larvaebut are only transverse bands across thedorsal surface of moth fly larvae. Bothfamilies have a spiracle on their hind endthat is surrounded by hydrophobic hairsand these often puncture the water surfacein shallow water. Both families have verysimple bodies, with no pro-legs and fullyformed unretractable head capsules.Stratiomyid larvae can grow to around 20 mm, while psychodids are usuallysmaller than 10 mm long.

Possible misidentificationsNo other dipteran larvae are as heavilysclerotised as moth and soldier fly larvae.Recently moulted or pale psychodids canlook a bit like ephydrids, but psychodidswill have each of their segments sub-dividedand the edges of the sclerites should bevisible even if they haven’t darkened.

Classification and distributionBoth families are fairly diverse with over 50 species each, but their taxonomy is stillunder review and these numbers are likelyto increase.

Habitat and ecologyPsychodids occur in a range of habitats,from rotting logs, wet soil and mud toshallow water. The fully aquatic species areusually found in still or slow-flowing water.Psychodid larvae eat decaying organicmatter and microalgae. The stratiomyidsoccur in similar habitats and eat similarfood. Both families are usually tolerant oforganic pollutants and some psychodids areknown to thrive in sewage treatment plants.

Natural historyAdult psychodids are odd-looking flies thataren’t often seen, except around blockeddrains when they signal the need for aplumber. They have hair-covered wings andantennae, and are thought to be one of themore primitive families of Diptera.

Moth flies and soldier flies(Families: Psychodidae and Stratiomyidae)

Stratiomyids often float. Their abdomen ends ina ring of water-repellent hairs that breaks thewater surface and helps them breathe airthrough their spiracles.

Pschodid larvae are found in shallow, nutrient-enriched waters. Some of them are semi-terrestrial or found in rotting wood.

Flies l 129

Distinguishing characteristics Black fly larvae have elongate, pear-shapedbodies, with a ‘suction disk’ at one end and apair of feathered mouthparts at the other.They hold onto rocks and other solidobjects in fast-flowing water and filter foodparticles from the water with their mouth-parts. Older larvae have a single pro-legwith small hooks, and a ‘gill spot’ on eitherside of their thoracic segments. Simuliidsmove in a leech-like manner, using their‘suction disk’ and a single thoracic pro-leg.The can reach 8 mm in length.

Possible misidentificationsSimuliid larvae superficially resembleleeches in their shape and movement. Theirhead capsules distinguish them fromleeches, while their peculiar body shapeeasily separates them from other fly larvae.

Classification and distributionThree genera, Simulium, Austrosimuliumand ‘Paracnephia’ occur in temperateAustralia, with fewer than 100 species.The taxonomy of this group has provenproblematic, with animals that appear thesame proving to be genetically distinct

species and animals that appear differentturning out to be genetically similar.

Habitat and ecologySimuliids are filter feeders in fast-flowingwater.

Natural historyThe suction cup at the end of a simuliid’sabdomen is more complicated than it firstappears. The edge of the cup is actuallysurrounded by a band of small hooks thatcatch on a silk mat that the larvae spin ontothe rock. If larvae are knocked free by roughwater, or if they have to flee a predator, theylet out a silk lifeline that stops them beingwashed away. Silk also plays a part in thepupal phase. Just before pupating, the larvaespin a small ‘hammock’ that will hold thepupal case in fast water. The pupal hammocknarrows downstream so that the pupal caseis safe from being dislodged by the flow, butthe upstream opening is wide enough to letthe mature pupa escape easily when it isready to float to the surface and emerge.Given all these uses, it is not surprising thatblack fly larvae have silk glands that stretchthe length of their bodies.

Black flies (Family: Simuliidae)

Adult black flies will sometimes bite humans,but it is thought that, like mosquitoes, it is onlyfemales that require a blood meal—before theylay their eggs.

Black fly larvae choose a place to attachthemselves based on the speed of the waterflowing over it. They use their fan-likemouthparts to filter the water as it flows past.


Distinguishing characteristicsThe tanyderids are elongate larvae with abroad, flat, sclerotised head capsule, a singlepair of posterior pro-legs and a number oflong fleshy projections that are attached totheir final segments and pro-legs.Tanyderids can grow to around 20 mm.

Possible misidentificationsSee Chironomidae and Ceratopogonidae.

Classification and distributionThere are three genera of tanyderids intemperate Australia: Eutanyderus andNothoderus from south-eastern Australiaand Radinocerus from Western Australia.None are common.

Habitat and ecologyTanyderid larvae are woodborers that occurin cool wood-filled streams.

Distinguishing characteristicsThe thaumaleids have a sclerotised headcapsule and a long simple body with a singleanterior and a single posterior pro-leg. Thefirst thoracic segment has a pair of smallsclerotised spiracles. When disturbed,thaumaleids move with a sideways bend,like slow dixids. Thaumaleids can grow toaround 10 mm.

Possible misidentificationsSee Ceratopogonidae (page 119) andChironomidae (page 120).

Classification and distributionThaumaleids are fairly rare and arerepresented by the genera Austrothaumaleaand Niphta.

Habitat and ecologyThaumaleids are grazers in wet areas nearwaterfalls and other fast-flowing habitats.

Family: Tanyderidae

Family: Thaumaleidae

Tanyderids are fairly rare, wood-boring larvae.

Thaumaleids are chironomid-like dipterans thatoccur in splash zones near waterfalls andcascades.

Mayflies l 131

Mayflies (Order: Ephemeroptera)

The mayflies are one of the more well-known stream insects. Their invertebrate fameis the result of their short lives as adults and their tendency to end up as fish food.The adults are a common sight, swarming over water during the warmer months.

ADULT MAYFLY

MAYFLY NYMPH

eye

foreleg

mid-leg

hind leg

pronotum BAETIDAE

CAENIDAE

wing buds

abdomen gills

forewing(only)

hind wing

forewing

unconnectedveins

terminal filament

cerci

‘round’ cells(Ameletopsidae only)


Characteristics of an adultAdult mayflies have large compound eyesand most have two pairs of wings. Thefront wing is always much larger than thehind wing and they are held togethervertically above the body when the animalis at rest. Most mayflies have three cerci ortails, though in some species (someAtalophlebia for example) the middle one is reduced or lost. Mayflies are the onlyaquatic insects to have two winged stages.Immediately after emerging, mayflies aredull grey with opaque wings. This stage isreferred to as the sub-imago, or ‘dun’ if youare a fly fishing enthusiast. Sub-imagos arefairly placid animals, biding their timeamongst streamside vegetation until thenext moult. The sub-imago stage lastsabout a day. During the next moult, adultslose a layer from each of their wings whichthen become transparent. This is the finaland sexually mature stage known as theimago or spinner. These are the animalsinvolved in swarming, mating and layingeggs. Most adults are short lived, lastingonly a matter of days or even hours.They do not feed and in some animals, thedigestive system is replaced with air-filledspaces that are thought to help the animalto balance during flight.

Characteristics of a nymphMayfly nymphs are distinguished by theirthree tails (two cerci and a terminalfilament) and the set of gills on each side oftheir abdomen. Different families of mayflyhave these organised differently and somehave protective covers (Caenidae andOniscigastridae). They have well-developedjointed legs, antennae and wingpads.Flattened nymphs tend to live in fasterflowing environments and move with rapidscurried movements sticking close to thestream bed. Rounded nymphs are usuallystrong swimmers and can move throughthe water like small fish. Often they propel

themselves by strokes of their tails, whichare fringed with swimming hairs.

Sexing mayfliesMale mayflies are often quite easy todistinguish from females by their split eyesand overly long forelegs. Both of thesestructures are used during mating. The split

This female baetid has lost its cerci, leaving itwith a single terminal filament.

Austrophlebioides is a common mayfly nymphin streams throughout eastern Australia.

Mayflies l 133

eyes give the males excellent visibility inmultiple directions and this allows them tomanoeuvre into a suitable mating positionwith a female while in flight. Usually thisinvolves the female flying into a swarm ofmales and being approached from below.The long forelegs are useful at this stage, asthey reach forward and grasp the female atthe base of her wings. Mating can take placein midair, or the couple can sometimesadjourn to a nearby landing site. The spliteyes of the male are evident in somenymphs during their final aquatic stages.

The sub-imago or dunMayflies are the only aquatic insects knownto go through two winged adult stages.The sub-imago stage is a bit of a mysteryand there are two theories put forward forits existence. The first is that it is a primitivecondition that has gone unchanged becauseit is useful. The sub-imago skin is coveredwith lots of microscopic structures thatresist wetting and this can assist an animalthat is struggling to free itself from thewater. The alternative explanation focuseson the long legs and tails of adults and it isthought that two stages are required toallow the legs to grow as long a they do. Itwould be difficult for the front legs toincrease to three or four times their originallength in a single moult.

Male mayflies have split eyes, long forelegs anda small pair of claspers immediately beneaththeir tails.

The sub-imago of Atalophlebia albiterminatahas distinctively patterned wings.

A final instar mayfly nymph foreleg. The adultleg, with a double claw and multiple tarsalsegments is packed tightly inside.

An adult Nousia strains to free itself from theextra layer of skin that it wore as a sub-imago.


Mayflies and compleat anglersThe mayfly is arguably the most importantinsect in fly fishing. Artificial flies have beendesigned to imitate many of the commonerspecies and often they are even designed toreplicate a particular part of their lifecycle.Some wet flies sink to imitate mayflynymphs. Others float just beneath the watersurface—they mimic emerging mayflies at avulnerable stage, struggling at the surfacewhile they inflate their newly formed wings.Dry flies rely on their feathers to keep themon top of the water surface. These flies canhave pale wings to imitate sub-imagos, clearwings for imagos, and flat wings splayed outon the surface to imitate spent mayflies,dead upon the water surface after they havelaid their eggs.

Environmental significanceMost mayflies occur in places with goodwater quality, although some families aremore tolerant than others. The taxonomyand tolerances of most families within thisgroup are relatively well known, so they canbe very useful in environmental assessment.Some of the more tolerant genera includeAtalophlebia (family Leptophlebiidae) andTasmanocoenis (family Caenidae).

ClassificationSeven families of mayfly are found intemperate Australia. Of these, the mostdiverse, common and widespread are thefamilies Leptophlebiidae and Baetidae.Currently, there are around 30 genera and100 species recognised in temperateAustralia. Mayfly taxonomy is still inprogress throughout the region, so thesenumbers are likely to increase.

Mayflies and the evolution of flightInsects did most of their evolving betweenthe Upper Carboniferous (260 mya) and theMid Cretaceous periods (80 mya). The morerecently evolved insect groups include thetrue flies (Diptera) and the moths andbutterflies (Lepidoptera), while the moreprimitive groups include the dragonflies(Odonata) and mayflies (Ephemeroptera).These more primitive winged groups can be recognised by the fact that they haven’tdeveloped a way of folding their wings outof the way when they aren’t using them.

Mayflies provide a link to the first crudeattempts at wings and flight. It wasoriginally thought that wings evolved fromstiff projections on the thorax of someterrestrial insect, but the gills of an aquaticmayfly nymph’s ancestor provide a muchmore likely precursor. Fossil insects havebeen found with gill-like structures on theirthoracic segments Like wings, these gillswere movable, and had a well-developed

vein network. These structures would haveoriginally helped with movementunderwater, but they would also work ascrude gliding wings when insects movedback onto land. Wings didn’t developproperly however, until the late Carbon-iferous. At this time land plants had becomequite large and offered lots of opportunitiesfor insects to jump from great heights andfinetune their recently evolved wings.

Atalophlebia albiterminata basks in the sun aftershedding its sub-imago skin.

Mayflies l 135

Key to families of mayfly nymphs

1 one set of abdominal gills larger than others, and covering them . . . . . . . . . . . . . . . . . 21 not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2(1) gills on abdominal segment 1 enlarged, elliptically shaped . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oniscigastridae (p. 142)

2 gills on abdominal segment 2 enlarged, square shaped . . . . . . . . . Caenidae (P. 138)

3(1) nymph moves with characteristic ‘rocking horse’ motion; gills V-shaped, and spine covered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Coloburiscidae (p. 139)

3 not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) flattened nymphs; setae on their tails arranged in sparse whorls; cling to theundersides of rocks, wood and plants. . . . . . . . . . . . . . . . . . . . Leptophlebiidae (p. 140)

4 rounded nymphs; hairs arranged on tails as a dense fringe; fringed tails make these animals strong swimmers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5(4) gills split, with the upper leaf plate-like and the lower feathery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ameletopsidae (p. 136)

5 gills single or if split, both parts similarly plate-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6(5) antennae shorter than head width; gills with a hardened edge and strut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Siphlonuridae (p. 143)

6 antennae longer than head width; gills without a hardened edge or strut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baetidae (p. 137)

Key to families of mayfly adults

1 hind wing obviously greater than 1/3 the length of the forewing . . . . . . . . . . . . . . . . . . 21 hind wing smaller than 1/3 the length of the forewing, or absent . . . . . . . . . . . . . . . . . 5

2(1) wings pink-purple, and/or with a cluster of cells near the apex that have morethan 5 sides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ameletopsidae (p. 136)

2 wings clear, grey, yellow or brown, and all cells with a maximum of five sides . . . . 3

3(2) 3 tails (2 cerci and one terminal filament) . . . . . . . . . . . . . . . . . . . Siphlonuridae (p. 143)3 2 tails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) small mayfly (found near lakes and slow-flowing parts of rivers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oniscigastridae (p. 142)

4 large mayfly (found near pebble /cobble streams and rivers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Coloburiscidae (p. 139)

5(1) with hind wings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 without hindwings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6(5) hind wings very small, margin of forewing with numerous unconnected marginal veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baetidae (most) (p. 137)

6 hind wings smaller than 1/3 the length of forewing, all marginal veins connected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leptophlebiidae (p. 140)

7(5) forewings with very few cross veins, all marginal veins connected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Caenidae (p. 138)

7 forewings with cross veins, some marginal veins unconnected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . some Baetidae (Bungona and Cloeon) (p. 137)


Distinguishing characteristicsAmeletopsids are large mayflies; the nymphsare dark and shiny with large heads androbust bodies. They have large gills with theupper part plate-like and the lower part splitinto many fine filaments giving it a featheryappearance. The outer cerci are denselyfringed with hairs on their inner margin,while the central tail or terminal filamenthas both sides fringed. These fringes of hairhelp propel them quickly through the water.Nymphs can exceed 20 mm. The adults haverobust yellow-brown bodies, sometimeswith bright pink-purple wings. A close lookat the forewings will reveal a cluster of cellsnear the tip, that are less square than othersand can have up to six or seven sides. Thecells on most mayfly wings have five sides orless (usually four) and this makes themroughly rectangular.

Possible misidentificationsThe Siphlonuridae and Baetidae may appearsimilar, but they both have a single plate-likegill, rather than the two-part, plate-like andtufted gills of the Ameletopsidae.

Classification and distributionThe family Ameletopsidae is represented bya single genus, Mirawara, in temperateAustralia. Three different species occuralong the east coast, but the family isentirely absent from Tasmania and WesternAustralia. Other genera from this family arefound in New Zealand and South America.

Habitat and ecologyMirawara is found in fast-flowing cobblestreams. It is a nocturnal predator with longteeth on its mandibles. It feeds on smaller

invertebrates such as mayflies andchironomids.

Natural historyAdults are found from October to April anddo not exhibit a strongly synchronousswarming behaviour. To compensate forthis, they are probably slightly more long-lived, to increase the chances of individualsfinding a mate.

Killer mayflies, purple perils (Family: Ameletopsidae)

Adult Mirawara are one of the largest Australianmayflies. This female measured over 20 mmlong.

Mirawara is the only predatory mayfly nymph inAustralia.

Mayflies l 137

Baetids (Family: Baetidae)

Distinguishing characteristicsThe Baetidae are small to medium-sizedmayflies (<10 mm) with rounded bodiesand mottled colourings. Their heads arewell rounded and bear a pair of longantennae. They have paired or single plate-like gills on their abdominal segments andfringes of setae on their tails. Baetids arestrong swimmers and move with rapidwiggles of their abdomen. The adults aresmall, fragile animals with heavily reducedor absent hindwings. Their forewings havefewer strong cross-veins than other mayfliesand the posterior wing margin is lined withshort, unconnected vein endings.

Possible misidentificationsNymphs of both the Ameletopsidae and theSiphlonuridae look a bit like the Baetidae.

Ameletopsids can be separated by their size,robustness and their plate and tufted gills.The siphlonurids have antennae that areshorter than half the length of the head andeach of their gills is reinforced with ahardened strut and margin. Baetids havelonger antennae and their gills lackreinforcing.

Classification and distributionThe Baetidae is a diverse family with a world-wide distribution. In temperate Australia,they are represented by five described genera:Bungona, Centroptilum, Cloeon, Offadensand Edmundsiops. The last two are the resultof ongoing taxonomic work that willreclassify the old genus Baetis. There arearound 16 recognised species, but this islikely to increase as the taxonomy is resolved.

A baetid nymph, showing its plate-like gills. Baetids are fast swimmers; their streamlinedshape reduces water resistance.

An adult female baetid (left) and a male (right). The male’s eye is clearly divided, and its front legsare very long for grabbing females in flight.


Habitat and ecologyBaetids are more diverse in cooler, flowingwaters, but species do occur in warmerlowland systems and sometimes even inwetlands. They mainly feed on algae grazedfrom a variety of substrates, including rocks,wood and aquatic plants.

Natural historyMost male mayflies have their eyes split into an upper and a lower lobe, but thesestructures are very well developed in theBaetidae. Male baetids have what is referred

to as a turbinate eye. These structures have ahuge upper lobe and a smaller lower lobe,giving the head a turban-wearingappearance. As with other mayflies, theseeyes are thought to help with the difficulttask of aerial mating.

Baetids often have several generations livingin the water simultaneously and differentspecies emerge at different times of the year,so emergence for the family is spreadthrough the warmer months betweenAugust and May.

Distinguishing characteristicsCaenid nymphs can be recognised by thegills on the second abdominal segmentbeing modified into square flaps coveringthe other gills. These flaps are thought toprotect the delicate gills from being cloggedwith fine sediment. Their body is flattenedand is only around 5–6 mm long. They areoften covered in hairs and fine algae, givingthem a fuzzy appearance. Some live animalscan have a pinkish colour, but most aregrey-brown. Caenid adults retain the stockybodies of the nymph when they emerge.Their most notable feature however, is theabsence of hind wings and the almost totallack of cross-veins in the forewings.

Possible misidentificationsOniscigastrid nymphs share thecharacteristic gill covers of the caenids, butoniscigastrids are larger and their body isnot flattened but streamlined. Oniscigastridgill covers are oval, rather than square, andlocated on the first abdominal segmentrather than the second.

Classification and distributionCaenids are found in most parts of theworld, with the odd exception of NewZealand. The family is represented intemperate Australia by three genera,Tasmanocoenis, Wundacaenis and Irpacaenis,and around 10 species.

A slow-moving caenid nymph is often overlookeddue to its small size and camouflage.

Adult caenids have stocky bodies and short,rounded wings. They lack hind wings.

Family: Caenidae

Mayflies l 139

Stream horses, spiny nymphs (Family: Coloburiscidae)

Habitat and ecologyCaenids are associated with slower flowing,silty areas of streams and standing waters.They are more pollution-tolerant than othergroups of mayflies and feed on detritus.

Natural historyAdults of Tasmanocoenis can form swarmsat the edge of streams in the early morning.Caenids have one or two generations a year.The adults emerge in spring and summer.Caenids are poor swimmers and mostlycrawl along the riverbed, or aroundmacrophytes. In the United Kingdom, thisfamily goes by the name ‘angler’s curse’ dueto the fact that their small size makes themdifficult to mimic with flies and yet they area really important source of trout food.

Caenid nymphs are often covered in silt andalgae, which adds to their camouflage.

Distinguishing characteristicsTheir common names well reflect theappearance of coloburiscid nymphs. Themost distinguishing characteristics are thespiny ‘V’ shaped gills and the hunched body.Their quick, nodding swimming motion isreminiscent of a galloping horse. The twofront pairs of legs have very long hairs andthe mouthparts are adorned with variousbrushes. Each spiny gill has a secondarybranch which forms a basal tuft offilaments. Nymphs also have a pair of smallfinger-like gills, one on each side of theirmouth. The cerci are densely covered withhairs and are used to propel the animalthrough the water. Coloburiscid adults arelarge, dark coloured mayflies, withsubstantial hind wings and a reduced, orabsent, central tail (terminal filament).

Possible misidentificationsThe unique shape of their gills makes itdifficult to confuse coloburiscid nymphswith other mayflies.

Classification and distributionA single genus of the Coloburiscidae ispresent in the highlands of south-easternAustralia. Coloburiscoides includes threedescribed species. This family is also foundin New Zealand and South America, butdoes not occur in Tasmania, WesternAustralia or northern Australia.

Coloburiscids use their distinctive spines toanchor themselves between rocks in thestream.


Habitat and ecologyColoburiscid nymphs live in fast-flowing,upland streams. They use the spiky gills toanchor themselves under rocks and resistbeing swept away by the flow. Their spikyappearance makes it tempting to think thatthey are predators. However they areharmless filterfeeders and collect organicparticles from the stream current usingmouthparts equipped with brushes and thefirst two pairs of legs fringed with long

hairs. The nymphs live mostly on or underrocks and submerged woody debris.

Natural historyThe nymphal stage lasts between six monthsand two years and the adults emergebetween November and March. Sub-imagosare thought to emerge in the late eveningand wait for the following day beforemoulting to the imago stage and swarmingthe following evening.

Distinguishing characteristicsLeptophlebiid nymphs can be quite variedin their appearance, but they all haveflattened bodies and heads, flattened legswith broad femurs, and prominent gillsalong the sides of their abdomen. Usuallythese are paired and vaguely leaf-like. Thesetae on their tails are arranged in rings, orwhorls along their length and the edges ofsome abdominal segments have small, butwell-developed backward pointing blades.Most nymphs are smaller than 20 mm.Adult leptophlebiid mayflies are veryvariable, but all have the hindwings smallerthan a third the length of the forewings.They can have two or three tails and comein a range of sizes.

Possible misidentificationsVery few other mayfly families are asdistinctly flattened as the leptoflebs.The caenids are flattened, but theirdistinctive gill covers should distinguishthem fairly easily.

Classification and distributionLeptophlebiidae is Australia’s most diversemayfly family. Leptophlebiids occurworldwide and are the dominant group inAustralia, New Zealand and South America.They are currently represented in temperateAustralia by 19 genera and 70 species.

Leptoflebs (Family: Leptophlebiidae)

Leptophlebiid nymphs are flat to avoid beingswept away in fast-flowing rivers.

Atalophlebia has feathery gills and lives in slow-flowing water.

Mayflies l 141

Atalomicria has an elongate pair of mouthpartsfor collecting detritus.

Jappa, one of the strangest leptoflebs, uses itsrobust horns while burrowing in soft sediments.

A sub-imago struggles free from its nymphalskin at the water surface.

A leptophlebiid adult male has enormous eyesthat take up most of its head.

Habitat and ecologyMost leptophlebiids probably collectdetritus from the surface of rocks and wood.They usually occur in fast-flowing streams,though Atalophlebia is typically found inslower flowing or still water amongst woodand aquatic plants. The horned leptophlebiid,Jappa, and some Ulmerophlebia areburrowing nymphs that tunnel in gravelly,sandy or silty stream beds. They feed on amixture of algae and collected detritus.

Natural historySome leptophlebiid genera have distinctivephysical characters that shed some light onthe way they live. Jappa has a pair of hornson its head that helps it while burrowing insofter sediments. Atalomicria has very longmaxillary palps with brushes on their endsthat are distinctive and might be involved incollecting detritus. Kirrara has broad gills

that form a skirt-like suction cup aroundthe abdomen, which helps it cling to rocksin fast-flowing water. Atalophlebia hasfeathery gills that increase the surface areaavailable to extract oxygen from the slow-flowing waters in which it lives. Many of theother genera such as Nousia, Austrophlebioidesand Tillyardophlebia are superficiallysimilar, but their broad, flattened bodies andgill-lined abdomens are ideal for life on theedges of cobbles in fast-flowing water.

Many of the flies used by Australian flyfishing enthusiasts are based onleptophlebiid adults. Common patternsinclude red spinners (Atalophlebia australis),black spinners (Atalophlebia albiterminata)and various duns (sub-imagos ofAtalophlebia sp.). These are all mayflies thatare common in the broader rivers and lakeswhere trout have been introduced.


Distinguishing characteristicsOniscigastrid nymphs have streamlinedbodies around 12–15 mm long. Their firstpair of gills forms oval flaps covering thefollowing gills. They have a row of smalldorsal spines along the mid-line of theirfirst five abdominal segments. Their cercihave a fringe of hairs. Adults have large hind wings and two tails.

Possible misidentificationsSee Caenidae (page 138).

Classification and distributionThe Oniscigastridae is represented in south-eastern Australia by a single genus,Tasmanophlebia, with three species.

This family also occurs in New Zealand andSouth America.

Habitat and ecologyNymphs live in slow-flowing streams and instill water bodies. They prefer sandyriverbeds and feed on detritus.

Natural historyNymphs leave the water just beforeemerging as sub-imagos crawling on torocks and boulders at the edge of thestream. Most oniscigastrids complete one ortwo generations a year. The bulk of theseemerge as adults between November andMarch.

Family: Oniscigastridae

Tasmanophlebia nymphs have their first pair of gills enlarged to cover the rest. This possiblyprotects them from silt.

Mayflies l 143

Family: Siphlonuridae

Distinguishing characteristicsSiphlonurid nymphs are robust, with a bodylength to about 15 mm. They have the gillson their abdominal segments reinforcedwith a hardened outer margin and by ahardened strut running through the middleof each gill. Their antennae are shorter thanhalf the length of the head. Their cerci aredensely fringed with hairs and are used forswimming. Adults are large dark mayflies,with three tails and large hind wings.

Possible misidentificationsSee Baetidae.

Classification and distributionThe Siphlonuridae is represented by a singlespecies, Ameletoides lacusalbinae, which isrestricted to the cold water of alpine areas insouth-eastern Australia and Tasmania.

Habitat and ecologySiphlonurid nymphs live in small alpinestreams and some lakes in the Kosciuszkoregion. They scrape algae from hard surfacessuch as rock or wood.

Natural historyNymphal development lasts up to two yearsand the adults emerge from September toJanuary. Siphlonurids are a good indicatorof fish-free streams and disappear almostentirely from streams with large predatoryfish in them such as large Galaxias orintroduced trout species. Much of theirsusceptibility to fish predation comes fromtheir habit of grazing the tops of rocks inthe pools of streams during broad daylight.This sort of behaviour is sensible only in theabsence of trout!

Siphlonurids look like baetids, but they aremuch bigger and have shorter antennae.

Ameletoides lacusalbinae grazes on detritus onthe tops of rocks in the pools of uplandstreams.


True bugs (Order: Hemiptera, Suborder: Heteroptera)

Although the term ‘bugs’ is often used as a nickname for all insects, true bugs arehemipterans, belonging to the suborder Heteroptera. There are around 270 aquaticor semi-aquatic species in Australian inland waters—many people will have heard ofbackswimmers, water striders or waterboatmen.

BACKSWIMMER

hind wing

eye

proboscis (beak)

abdomen

pronotum

antenna

front wing

femur

tibia

tarsi

preapical claws

apical claws

Characteristics of aquatic and semi-aquatic bugsThe hemipteran body varies from elongatedand boat-shaped in backswimmers to leaf-like in water scorpions. Adult formsrange from a tiny 1 mm (small waterstriders and velvet water bugs) to 75 mm(giant water bugs).

The hind legs of some families(waterboatmen, backswimmers) arewidened and covered by ‘swimming’ hairs

while the long hind and middle legs ofwater striders are specialised to support theanimal on the surface of the water. Somegroups have unusually folded forelegsspecialised for grasping prey in the samemanner as praying mantises.

One feature common to all aquatic andsemi-aquatic bugs is their piercing andsucking mouthparts. Adults and nymphsfrom this group look very similar.Nymphs lack wings and are smaller.

True bugs l 145

Piercing mouthparts are characteristic of all aquatic bugs, from the 30 mm giant water bug (left) tothe 1 mm small water strider (right).

Living on different levels The true bugs are an interesting groupbecause of the many different ways that theylive in and around water. Some families suchas the notonectids and corixids are fullyaquatic and spend most of their time underwater, while other families such as gerridsand veliids spend most of the their time onthe water surface. Sometimes the surfacedwellers will compete with the fully aquaticbugs for prey, and a struggling insectensnared in the water film has an equalchance of being dragged under the water andconsumed, as being plucked from the filmand sucked dry above the water surface.Many more families are semi-aquatic and livealong the water margins, splitting their time

between the water surface and dry land. Mostfully grown bugs have well formed wings andwill eventually fly away from the water wherethey grew up, to colonise new water bodies.

Environmental significanceHemipterans are relatively tolerant of manyforms of pollution. Surface dwellers inparticular have very little physical connectionwith water and therefore are less dependenton the water quality. However, oil andsurfactants (e.g. household detergents)decrease the surface tension of the waterand this reduces the ability of the surfacedwellers to repel water with thehydrophobic hairs on their legs, thuscausing them to sink.

This water strider (Family: Gerridae) will sink ifpollutants reduce the surface tension of the water.

Members of the Ochteridae are usually foundonly at the edge of aquatic habitats.


Classification Hemiptera is a common and diverse order.In Australia it includes over 5650 speciesfrom three different suborders. Aquatic andsemi-aquatic hemipterans belong to thelargest suborder Heteroptera, whichincludes some 270 different species from 19 different families, of which two families,Hermatobatidae and Omaniidae, areexclusively marine. Many species areendemic to Australia but most of the

genera occur in other parts of the world.In this book we include 12 families that are both strongly associated with freshwaterand relatively common. The SaldidaeOchteridae, Dipsocoridae, andLeptopodidae have not been includedthough they might sometimes be found instreams and lakes after heavy rain, whilemembers of the aquatic Aphelocheiridaeoccur only in northern Australia.

Love, death and musicThe males in several groups (e.g. Corixidae,Notonectidae) produce sounds to attractfemales. This is called stridulation andinvolves them rubbing the pegs on theirfront legs across a ridge on the front of theirhead. The males of some water striders(Family: Gerridae) express their feelings bymaking rhythmic ripples on the water.

Copulation occurs in the water or on thewater surface and eggs are laid on thesurface, inside aquatic plants or on thebottom of a water body. Belostomatid eggsare laid on the male’s back. This protectsthem from both the male and otherpredators.

With the possible exception of some water-boatmen (Family: Corixidae) which consumea mixture of detritus and zooplankton, allaquatic bugs are predators. They use theirpiercing mouthparts to suck the body fluidsfrom their prey. Surface dwellers such aswater striders catch terrestrial insects thathave fallen into the water; backswimmerschase small creatures in the water and waterscorpions ambush their prey.

Hemipterans do not have a pupal stage andtheir nymphs look and behave in a similarway to the adults. Young nymphs face a realpossibility of being eaten by adults and thisis a good reason to stay clear of theirparents.

Waterboatmen make sounds by rubbing thepegs on their front legs across a ridge on thefront of their head.

An immature backswimmer looks and behavesin a very similar way to an adult backswimmer.

True bugs l 147

Key to Hemiptera

1 antennae as long or longer than head, clearly visible from above; animals live on water surface or amongst fringing vegetation; semi-aquatic . . . . . . . . . . . . . . . . . . . . . . 2

1 antennae shorter than head; animals live in water or around the edge of water bodies; aquatic or semi-aquatic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2(1) body long and slender; head as long as thorax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Water measurers (Hydrometridae, page 153)

2 head and body stouter; head not as long as thorax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3(2) femora of hind legs extending well beyond tip of abdomen; gap between the front and mid-legs greater than that between the mid and the hind legs . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Water striders (Gerridae, page 152)3 femora of hind legs not extending well beyond tip of abdomen; gaps between the

front, mid and hind legs are all equal; body shorter than 5 mm . . . . . . . . . . . . . . . . . . . 4

4(3) winged forms with scutellum covered by the pronotum; wingless forms with pronotum covering mesonotum or not; tarsal claws preapical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Small water striders (Veliidae, page 159)

4 winged forms with scutellum exposed behind pronotum; wingless forms with pronotum never covering mesonotum; tarsal claws apical . . . . . . . . . . . . . . . . . . . . . . . . 5

5(4) hind legs longer than body length; winged and wingless forms present; tarsi 3-segmented; generally greenish or yellowish in colour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Water treaders (Mesoveliidae, page 159)

5 hind legs shorter than body length; only winged forms known in Australia; tarsi 2-segmented; short dense body hairs giving ‘velvet’ appearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Velvet water bugs (Hebridae, page 159)

6(1) antennae completely hidden; body and head broad with a pair of widely separated eyes positioned at front of head; forelegs with broad femur, specialised for grasping; semi-aquatic; up to 10–11 mm long . . . . . . . Toad bugs (Gelastocoridae, page 151)

6 without the above combination of characters; aquatic . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

7(6) elongate non-retractile breathing tube present at tip of abdomen; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Water scorpions (Nepidae, page 155)

7 abdomen without elongate breathing tube, but short, retractile air straps may be present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8(7) tarsal segments of first pair of legs scoop-like; head appearing triangular from the front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Waterboatmen (Corixidae, page 149)

8 without the above combination of characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

9(8) forelegs modified for grasping; swim the right way up . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 forelegs are not modified for grasping; swim with ventral side up . . . . . . . . . . . . . . . 11

10(9) membranous part of forewings with veins; adults 10–15 mm long; edges of body with dark and light bands . . . . . . . . . . Creeping water bugs (Naucoridae, page 154)

10 membranous part of forewings without veins; adults around 25–75 mm long; body uniform brown . . . . . . . . . . . . . . . Giant water bugs (Belostomatidae, page 148)

11(9) adults around 4–10 mm long; eyes large, close together; body elongated; hind legs oar-like; common. . . . . . . . . . . . Backswimmers (Notonectidae, page 157)

11 adults 2–3 mm long; eyes smaller, not close together; body highly convex; hind legs normal; less common . . . . . . Pygmy backswimmers (Pleidae, page 158)


Distinguishing characteristicsGiant water bugs have flattened bodies,strong raptorial grasping forelegs, and hindswimming legs fringed with hairs for apowerful stroke. The species of Lethocerusfrom northern and eastern Australia canreach 75 mm in body length. These are thelargest hemipterans in Australia. Voraciouspredators, they may become a nuisance infish farms. The genus Diplonychus, foundover much of northern and eastern Australia,is smaller and reaches around 30 mm inlength. It is advisable not to catch these bugswith your bare hands as they can inflict apainful bite with their powerful beak.

Possible misidentificationsSee Naucoridae (page 154).

Classification and distributionTwo genera, Lethocerus and Diplonychus, arefound in Australia. Diplonychus includes justtwo species, one of which, Diplonychuseques, is common in south-eastern Australia.

Habitat and ecologyBelostomatids live in wetlands, ponds and lakes that have plenty of aquaticvegetation. They are good swimmers andcan chase after their prey over a shortdistance. They spend most of their timehanging in the water column waiting for an opportunity to catch prey. With theirimposing size, belostomatids are often atthe top of the food chain and are one ofthe few invertebrates that can readily feedon small fish.

Natural historyThe female Diplonychus lays her eggs on theback of a male. In this position they are safefrom the male and other predators. Themale shows tender love and care by strokingthe eggs with his hind legs to maintain afresh flow of water. However, if an egg getsdislodged he readily eats it! It remains amystery whether the egg-carrying male isactually the ‘father’ of the prospectiveoffspring.

Giant water bugs (Family: Belostomatidae)

The genus Diplonychus is found over much of northern and eastern Australia.

True bugs l 149

As in many other groups of aquatic bugs,belostomatid nymphs stay away from theirparents to avoid being eaten.

Males have been reported to makestridulatory sounds to attract females.

Belostomatids have been seencommunicating with each other byrhythmical push-up-like body movementsnear the surface of the water.

Waterboatmen (Family: Corixidae)

A belastomatid devouring a fly caught from thewater surface.

A male Diplonychus with eggs on his back.

Distinguishing characteristicsWaterboatmen are slightly flattened bugswith a streamlined body form. Theirmouthparts are in the form of a short,blunt, triangular rostrum, unlike the longsharp beak of the majority of other aquaticbugs. Their hind and middle legs are fringedwith swimming hairs, while their forelegsare short and scoop-like. One peculiarfeature of male corixids is theirasymmetrical abdomen—some sclerites onthe underside of the abdomen are muchlarger on one side than the other. Females,however, are perfectly symmetrical. Adultsrange in size from 1.5 to 15 mm long.

Possible misidentificationsCorixids can be confused withbackswimmers (Notonectidae). When alivethese groups are easy to distinguish asnotonectids swim with their legs uppermostwhile corixids swim in the ordinary fashionwith their legs held underneath their bodies.

If the animal is dead, check its back: theback of a corixid is dark and flat, while thatof a notonectid is lighter in colour andmuch more convex. The corixid beak isshort and triangular.

Classification and distributionThirty one species and five genera ofwaterboatmen are known from Australia.

Waterboatmen are slightly flattened bugs with astreamlined body form.


The most common genera are Sigara andthe much smaller Micronecta. Corixids aredistributed throughout Australia with theexception of the genus Diaprepocoris, whichoccurs mainly in the southern half ofAustralia.

Habitat and ecologyCorixids occur in slow-moving or stillwaters among aquatic vegetation. Often theyare the most common insects in ponds andat the edges of lakes and slow-flowingstreams among vegetation. They areexcellent fliers and can easily move fromone water body to another.

The food of corixids is a combination ofother insects such as mosquito larvae andbits of vegetation which they grind upinternally. Because of their abundance,corixids themselves are a good source offood for fish.

Natural historyAdult males of Sigara produce chirpingsounds—or stridulations—to attractfemales. They do this by rubbing theirfront femora, equipped with special pegs,against the sharp edge of their head.Some Micronecta species stridulate withtheir abdominal segments. Females attacheggs to submerged objects. Nymphs looksimilar to adults but without wings.They moult five times before becomingmature adult waterboatmen.

The air reservoir of corixids consists of abubble of air over the exposed abdominalsurface and beneath the wings. The air isreplenished through spaces between thehead and pronotum by the animals breakingthe surface film with the pronotum.

Like other corixids, Sigara sp. carries an airbubble around its abdomen.

Although only around 5 mm in size, Micronectais a very common and abundant genus.

True bugs l 151

Distinguishing characteristicsToad bugs are rather bizarre-looking bugs.With their wide prothorax, bulging eyes and the ability to suddenly jump on theirprey, they really justify their name. Theirforelegs are scythe-like with widenedfemora adapted for grasping and holdingprey. Adults have wings but rarely fly.They are around 10 mm long.

Possible misidentificationsNone.

Classification and distributionTwenty species from the single genusNerthra, are found throughout Australia.

Habitat and ecologyGelastocorids live on the edges of still waterbodies and can crawl in and out of thewater. They prefer moist conditions, such asin rainforests, and may be found at aconsiderable distance from water.

Toad bugs are predators. They crawl aroundslowly looking for suitable victims.

When they find something, they quicklyjump on it, dispatching it with their needle-like mouthparts.

Natural historyGelastocorids represent an earlyevolutionary stage when aquatic bugs beganto colonise the freshwater environment, andthis is why they are comfortable in or out ofwater. Males of some Nerthra species fromthe northern hemisphere can producesounds to attract females.

Toad bugs don’t turn up very often.

Toad bugs crawl in and out of the water.

Toad bugs (Family: Gelastocoridae)


Distinguishing characteristicsWater striders have long middle and hindlegs, at least three times longer than theirforelegs. They hold their forelegs close totheir body and spread their middle and hindlegs on the water surface, often giving theimpression that they have only four insteadof six legs. Like other surface bugs, they arecovered in a coat of unwettable hairs.The hydrophobic hairs on their tarsi,together with their preapical claws, helpthem to stay on the surface film withoutbreaking through it. Their body has aspindle-like shape; adults have wings andcan fly. They are usually darkly colouredand around 8 mm in length. Their leg spancan be more than 50 mm.

Possible misidentificationsSee Veliidae, Mesoveliidae and Hebridae(page 159).

Classification and distributionFour subfamilies and at least 36 species are known from Australian inland waters,although most of this diversity is intropical waters. Of these, the subfamilyGerrinae and the genera Tenagogerris andAquarius are common in south-easternAustralia. Tenagogerris is endemic to

Australia. Three genera have colonisedmarine environments.

Habitat and ecologyGerrids occur in small or large groups onthe surface of ponds, lakes, and the edges ofwetlands or slow-flowing rivers. They areextremely difficult to collect (andphotograph!) as they have excellent eyesightand, when approached within a metre or so,tend to skate away. Gerrids are activepredators and sense their prey using rippleson the water surface. Once they havetrapped an aquatic insect or otherinvertebrate, they stab it with their beak.

Cannibalism is not uncommon and thejuveniles stay together keeping a safedistance from their hungry parents.Often cooperation takes place and severalindividuals, sometimes even from differentspecies, hunt together—like wolves in apack—to capture a larger prey.

Natural historyMales and females communicate by makingrhythmic ripples on the water surface. Amale will use ripple signals to attract afemale and stimulate her when sheresponds, as well as to tell other males tostay away from his mate.

Water striders (Family: Gerridae)

Water striders occur in a variety of habitats,including slow-flowing rivers.

Some water striders such as this Rheumatometrafrom Tasmania have a more rounded body shape.

True bugs l 153

Mating behavior is complex, ranging frommonogamy, when a male stays with hisfemale protecting her from other males, topolygamy when males try to mate with asmany females as possible.

Sometimes males get together to display forfemales and the ‘best’ male gets to mate

more than others do—this is called‘polygyny’. Eggs are deposited on floatingobjects or sometimes underwater.

The ability of gerrids to spread their weightand skate on the water surface is soimpressive that in some parts of Canadathey are called ‘Jesus bugs’.

Water measurers (Family: Hydrometridae)

Distinguishing characteristicsAn elongated head and a stick-like bodymakes ‘water measurers’ look like yardsticksfor measuring water surface. With eyespositioned halfway up the long head andantennae mounted at its end, these animalslook both delicate and comical.Hydrometrids are usually pale brown andrather cryptic. Their slow movement andslender limbs allow them to blend in withvegetation on the water surface. Fully grownanimals rarely exceed 15 mm.

Possible misidentificationsTheir peculiar appearance makes it veryhard to confuse them with any other group.

Classification and distributionAll nine species of Australian hydrometridsbelong to the genus Hydrometra. H. strigosa

is one of the most common species.Both the family and the genus are foundthroughout the world.

Habitat and ecologyHydrometrids live on the surface of thewater at the edges of wetlands, lakes andponds, often hiding amongst vegetation.They are normally slow-moving animals butcan move rapidly when disturbed. They feedor scavenge on small animals fallen on thesurface of the water. Surface-dwellingspringtails are one of their favourite foods.

Natural historyThe lifecycle of Australian hydrometrids hasnot been studied intensively. In other partsof the world they have been observed tohave 5 instars (immature stages) andbecome adults in 4–6 weeks.

Water measurers have a delicate and comical look about them.


Distinguishing characteristicsCreeping water bugs have a flattened ovalbody and head. Their forelegs are modifiedfor grasping with robust femurs andsimplified tibiae and tarsi for holding thebody of their prey. Most species have astriped pattern along their sides. The lengthof the adult is less than 11 mm.

Possible misidentificationsNaucorids look similar in general shape tobelostomatids. They also have very similarforelegs. Adults can be separated by size, asbelostomatid adults are at least 25 mm long.Distinction is more difficult when it comesto juveniles. Belostomatid nymphs havebulging eyes and pointy heads, while thenaucorids have eyes that fit within theoutline of their blunt-shaped heads.

Classification and distributionNaucoris is the only genus of Naucoridaefound in Australia. There are six species ofwhich Naucoris congrex is common insouth-eastern Australia.

Habitat and ecologyDespite their name creeping bugs are verygood swimmers and inhabit still and slow-flowing waters. Like other hemipterans, theyare predators. They catch and hold theirprey with their raptorial legs.

Natural historyMale naucorids can produce stridulatorysounds to attract females. Nymphs undergofive moults and look similar to adults.Adults have wings and can quickly dispersefrom one water body to another. Creepingwater bugs rely on atmospheric oxygen andhave to come up to the surface to renewtheir air supply from time to time.

Creeping water bugs (Family: Naucoridae)

Naucoris is the only genus of Naucoridae foundin Australia.

Creeping water bugs catch and hold their preywith their raptorial legs.

True bugs l 155

Distinguishing characteristicsNepids occur in two forms: one with abroad leaf-like body (water scorpions) andthe other with a stick-like body (needlebugs). Both forms have pincer-like forelegsadapted for seizing prey and a long, thinbreathing tube at the tip of the abdomen.This breathing tube is made up of two rod-like structures and is extended above thesurface of the water. It acts like a snorkel,giving the animal a supply of air, without itconstantly having to re-visit the surface.

Possible misidentificationsSome wide-bodied nepids could beconfused with belostomatids but only thenepids have a breathing tube.

Classification and distributionWater scorpions are placed in the subfamilyNepinae, with a single genus Laccotrephes.

Needle bugs are placed in the subfamilyRanatrinae, with four genera, Ranatra,Goondnomdanepa, Austronepa andCercotmetus. The genera Ranatra andLaccotrephes are common throughoutAustralia. The genera Goondnomdanepa andAustronepa are endemic.

Habitat and ecologyNepids occur in a variety of wetlands andponds among debris and aquatic vegetationwhere their body is well camouflaged.Only the genus Goondnomdanepa from thetropical north of Australia has been foundunder rocks in flowing water. Nepids crawlaround slowly and are poor swimmers. Ifdisturbed, they can slowly paddle throughthe water.

Nepids ambush unsuspecting prey with aquick grasping action of their forelegs.

Water scorpions and needle bugs (Family: Nepidae)

Nepids are separated into two groups: water scorpions (left) have a leaf-like body, while needlebugs (right) have a stick-like body.


Their two large eyes give them excellentsight and they can easily catch fastswimming animals such as waterboatmenor small fish, killing their prey quickly bystabbing it with their beak-like proboscis.

Natural historyMales can produce sounds to attractfemales. The female lays her eggs intodecaying wood or in soft plant stems.Nymphs go through five moults beforereaching the adult stage. Despite their sizeand cumbersome appearance, nepids aresurprisingly quick to colonise new waterbodies. They can sometimes be found inroadside ditches and other temporary pondsafter flooding.Nepids can easily catch fast-swimming animals.

Sit-and-wait predatorsWater scorpions (Family: Nepidae) look likea piece of vegetation or a stick and they relyon being inconspicuous. Like all hemipterans,they breathe air, but regularly swimming tothe surface would reveal their camouflage totheir prey. These animals have come up withan elegant solution. They use a snorkel-likebreathing tube at the end of their abdomen.The breathing tube, although quite long,rarely exceeds the length of the animal’sbody. So what restricts the length of thebreathing tube? If the breathing tube is toolong, the exhaled carbon dioxide will notescape from the tube and will preventoxygen from getting in. For the same reasonhumans cannot use a longer snorkel toswim in deeper water.

Water scorpions use a snorkel-like breathingtube at the end of their abdomen.

True bugs l 157

Distinguishing characteristicsBackswimmers can be recognised by theirconvex backs and their large eyes, whichoccupy most of the head. Their hind legs areelongated and modified for swimming withfringes of hair that help to push themthrough the water. Their name reflects theirunusual behaviour of swimming upsidedown, performing a kind of backstroke. As aresult of this switch in swimming style, theback of some notonectids is light-colouredso that the animal is not conspicuousagainst the light of the sky. Some hovermid-water in search of prey. This behaviourmeans that they are often the first animalsto be spotted in ponds. Adults range from 4 to10 mm long.

Possible misidentificationsImmature backswimmers coud be confusedwith their smaller relatives, pygmybackswimmers. However, adult pygmybackswimmers are less than 3 mm long andhave a much rounder body thannotonectids.

Backswimmers can sometimes be confusedwith waterboatmen (see Corixidae).

Classification and distributionIn Australia, the family Notonectidaeincludes six genera of which Enithares(5 species) and Anisops (30 species) are themost common.

Habitat and ecologyBackswimmers are common in all still andslow-flowing water bodies. They fly easilyand can therefore colonise new ponds andwetlands quite quickly. They are predatorsfeeding on a mixture of invertebrates fromthe open water and the water surface.

Natural historyBackswimmer males can produce sounds toattract females. Eggs are often depositedinto water plants. Juveniles look like adultsand behave in a similar way. However, oneof a nymph’s prime tasks is to avoid beingeaten by its parents.

Backswimmers breathe atmospheric oxygenand, although they carry a bubble of air onthe underside of their abdomen, they haveto come to the surface to renew their suppliesfrom time to time. Some notonectids suchas Anisops have a blood pigment similar to

Backswimmers (Family: Notonectidae)

The name backswimmers reflects the unusualway these insects swim (Enithares sp.).

Backswimmer nymphs look much like adults:often they have a very light-coloured back.


Pygmy backswimmers (Family: Pleidae)

ours, which is very efficient at carryingoxygen. They can therefore carry smallerbubbles than other bugs and remainneutrally buoyant. This allows them to huntmid-water, without sinking or constantlyreturning to the surface. Their upside downbodies and grasping forelegs allowbackswimmers to hunt animals that havefallen on the water surface.

Backswimmers are very active predators and in the northern hemisphere there arereports of them attacking small fish. Theycan inflict a painful stab or bite—so handlethem with care!

Distinguishing characteristicsAs their name suggests, pygmybackswimmers look very much like smallbackswimmers (Notonectidae). However,they have a highly convex body, are less than3 mm long, and lack the oar-like hind legsof notonectids. They are much less commonthan notonectids and, due to their smallsize, are often overlooked in samples.

Possible misidentificationsSee Notonectidae (page 157).

Classification and distributionThree species of the widespread genusNeoplea are described in Australia but onlytwo occur in south-eastern Austrtalia.

Habitat and ecologyPygmy backswimmers can be found in stillwater bodies among aquatic vegetation.Often they prefer to crawl among vegetationrather than swim. They prey onzooplankton, tiny animals smaller thanthemselves, and carry a bubble of air undertheir wings on the ventral side of theirabdomen.

Natural historyLittle is know about the lifecycle of pygmybackswimmers in Australia. Nymphs looksimilar to adults.

Anisops carrying a reflective bubble of air onthe under side of its abdomen.

Pygmy backswimmers can be recognised bytheir small size, convex body and widelyseparated eyes.

True bugs l 159

Small water striders, water treaders and velvet water bugs(Families: Veliidae, Mesoveliidae and Hebridae)

These three families are combined becauseof similarities in their appearance andhabitat.

Distinguishing characteristicsThese are small bugs (1–4.5 mm) withrelatively short legs. Tufts of hydrophobichair at the tip of their tarsi hold them on thewater surface while in Veliidae the claws arealso inserted preapically. Non-winged adultforms occur among Veliidae andMesoveliidae, making it difficult todistinguish between immature and adultstages, but the nymphs always have only onesegmented tarsi. Unlike the gerrids (water

striders) which skate or scull across thewater surface, members of these familieseither walk or run.

Possible misidentificationsMembers of these families can be confusedwith the water striders. However, waterstriders have long middle and hind legs withthe femora of both the middle and hind legsextending well beyond the edge of the body.Gerrids can also be recognised because thegap between their front and middle legs isgreater than the gap between their middleand hind legs. Veliidae can be distinguishedby preapical claws and, in winged forms,

Small water striders (Family: Veliidae) have both winged and wingless adult forms.

Small water striders (Family: Veliidae) prey and scavenge on small invertebrates fallen on the watersurface.


the scutellum is covered by the pronotum.Hebridae and Mesoveliidae both have apicalclaws and the scutellum exposed behind thepronotum in winged forms. Hebridae have2-segmented tarsi and hind legs shorterthan the body, while Mesoveliidae have 3-segmented tarsi and hind legs longer thanthe body.

Classification and distributionVeliidae has 12 genera and some 66 speciesin Australia. Five genera occur in south-eastern Australia with Microvelia being themost common and diverse genus.

Mesoveliidae in Australia has two genera,Mesovelia (widespread) and Austrovelia(north Queensland), but only Mesovelia issemi-aquatic. Mesovelia hungerfordi iscommon in south-eastern Australia.

Hebridae in Australia has two genera,Hebrus and Merragata, with one species ofeach common in south-eastern Australia.

Habitat and ecologyThese semi-aquatic bugs are all surface oredge dwellers and can be found in still andslow-flowing waters. They prey andscavenge on small invertebrates fallen on thewater surface. Like the larger water stridersthese groups can detect their prey byvibrations on the surface of the water.

Natural historyThe lifecycle comprises five moults. Veliidaeand Mesoveliidae have winged and winglessforms of adults while Hebridae are onlyknown as winged forms. Wingedmesoveliids are sometimes found with themembranous part of their wings ripped off.This is possibly to get the wings out of theway before mating takes place.

Water treaders (Family: Mesoveliidae) have hind legs longer than their body.

l 161

Dragonflies and damselflies (Order: Odonata, Suborders: Epiproctophora and Zygoptera)

The odonates are one of the best-known group of freshwater invertebrates. Theyhave a special place in human history, appearing in Japanese art, English literature,and even ancient Greek writings.

movable hook

EPIPROCTOPHORA (DRAGONFLIES) ZYGOPTERA (DAMSELFLIES)

wing buds

wing buds

abdomen

terminal gills

ODONATE MOUTHPARTS (UNEXTENDED) ODONATE MOUTHPARTS (STRIKING)

eye

labial palp

hinge

tibia

tarsi

femur

postmentum

prementum

premental setae

labial palpteeth


Characteristics of an adultAdult dragonflies and damselflies are acolourful and obvious part of freshwatersystems. They have a rather distinctiveshape, with a highly fused thorax and anelongated abdomen. The thorax containsthe musculature to power four large wings,which are responsible for the animal’sincredible flight speed (around 50 km/h).Odonates are also exceptionally controlledfliers (compared to the hectic flight of thecaddisflies for example) and this allowsthem to be one of the most efficient aerialpredators in the insect world. Large eyes,long, spine-covered legs and largemouthparts help them dispatch prey such as butterflies and smaller dragonflies whileon the wing.

Characteristics of a larvaDespite having wing buds, the juvenile stageis usually referred to as a larva, not a nymph,but either name is recognised. All dragonflylarvae are predatory. They tend to be slow-moving predators that rely on camouflagetogether with the strike from theirremarkable mouthparts to catch prey.Their jaws are long, hinged structures thatfold up underneath the head. Unextended,the mouthparts have a pair of labial palps(paired lower lips) that are either pointedand rest below the mandibles (upper jaws),or flat and cover the mouthparts totallyforming a ‘mask’. The mask is characteristicof the corduliid and libellulid-likedragonflies. In both cases, the palps arearmed with teeth and these are used to

Austroaeschna sp. is a common aeshnid-likedragonfly larva found in temperate Australianstreams.

Austrolestes psyche is a typical lestid damselflylarva, with a slender abdomen and well-developed terminal gills.

Hemicordulia tau is a common dragonflythroughout temperate Australia.

Ischnura heterosticta is a common damselflythroughout Australia and the Pacific.

Dragonflies and damselflies l 163

grasp prey when the mouthparts areextended during a strike.

Telling dragons from damselsDragonflies tend to be more stockily builtthan damselflies and, as a general rule,resting dragonflies hold their wings flat oneither side of the body, while damselflieshold their wings pressed together over theirbacks. There are a few exceptions to thisrule, such as the Megapodagrionidae andthe Diphlebiidae. Both these damselflyfamilies adopt the pose of a dragonfly, butthey are too slender to be confused withdragonflies. A failsafe way to separate thetwo groups is to look closely at the animals.The hind wings on dragonflies are broaderthan their forewings, while the forewingsand hind wings of damselflies are of similarwidth. The eyes on damselflies are widelyseparated when viewed from above, whiledragonfly eyes usually touch or nearly touch in the middle of their heads. Larvaldamselflies are more slender than dragonfliesand have three long gills attached to the endof their abdomen. Dragonflies are notablystockier and have their gills inside theirabdomen.

Jet bugsLarval dragonflies breathe by sucking waterinto their abdomen where it reaches theirinternal gills, then squeezing it out.Threatened by a larger predator—such as afish or a Waterwatch volunteer—they cansqueeze the water out with enough force tojet propel themselves forward.

Mudeyes and coutasDragonfly larvae are often used by fishingenthusiasts, who have dubbed them‘mudeyes’. Mudeyes are usually from thecorduliid/libellulid group of dragonflies, butthe term can be used for all dragonfly larvae.The aeshnid larvae sometimes get theseparate name ‘coutas’, possibly because oftheir sleek, predatory, barracuda-like looks.

Ancient historyThe oldest odonate fossils have beenrecovered from rocks from the Carbon-iferous period (320 mya). These animalswere often quite large: one genus,Meganeura, had a wingspan of around 60 cm. This is large enough to carry off asmall mouse! Dragonflies and damselfliesare unable to fold their wings over theirabdomen and this feature suggests that theyare an ancient and relatively primitivegroup. Mayflies are a similarly primitive

Adult dragonflies have their eyes close togetherand hold their wings flat. This is Hemicorduliatau.

Adult damselflies have their eyes separated byroughly an eye-width, and usually hold theirwings together vertically above their backs. This is Synlestes weyersii.


group, whereas true flies, such as tipulidsand midges, are considered quite advancedamong the winged insects.

Environmental significanceDragonflies and damselflies occur in a widevariety of habitats and some can withstanda range of environmental stresses. They arequite useful as indicators of environmentalimpact when studied at family (or lower)levels of taxonomy. A healthy stream,billabong or wetland usually supports adiverse range of odonates, while animpacted site may only boast a couple of themore pollution-tolerant species.

Pollution-tolerant odonates include thelarge Austroaeschna unicornis, Hemicorduliatau and the damselfly Ischnura heterosticta.These animals can be found in many urbanstreams and wetlands.

ClassificationThere are more than 300 species of Odonatarecognised in Australia and these belong to30 families, 22 of which occur in south-

eastern Australia. Few of these families aretotally endemic, though this is changing asthe taxonomy is reviewed. Identification ofsome families within the Epiproctophora isdifficult, so some of these families have beengrouped based on similarities. The familiesand family groups covered in this textinclude:

Zygoptera (Damselflies):Coenagrionidae, Diphlebiidae,Hemiphlebiidae, Isostictidae, Lestidae,Megapodagrionidae, Protoneuridae, andSynlestidae.

Epiproctophora (formerly Anisoptera)(Dragonflies):aeshnid-like dragonflies (Telephlebiidae,Aeshnidae), corduliid/libellulid-likedragonflies (Austrocorduliidae,Cordulephyidae, Synthemistidae,Gomphomacromiidae, Hemicorduliidae,Urothemistidae and Libellulidae),Gomphidae and Lindeniidae, Petaluridaeand the Primitive dragonflies(Archipetaliidae, Austropetaliidae).

Dragonfly larvae can often be identified by their characteristic mouthparts. Austroaeschna unicornis(left) has a flat prementum, while Hemicordulia tau (right) has a ladle-shaped prementum.


Killer chameleonsLarval dragonflies hunt their prey either bystealthily stalking it, or by remaining totallystill and waiting for it to move within rangeof their deadly mouthparts. A combinationof colour and shape helps many dragonflylarvae to make themselves well camouflaged.Some larvae have mottled patterns to matchtheir backgrounds and these can sometimesbe altered if the background changes. Unlikechameleons, which can alter their colour

patterns in a matter of seconds, dragonflylarvae can only change colour when theymoult. Their colours mimic those aroundthem and seem to set as the new skinhardens. Sometimes damselflies from thesame species, in the same pond, can bebrown or green depending on whether theyspend their time on dead wood or aquaticplants. Some of the less active dragonflylarvae such as synthemids can incorporatealgae into their camouflage.

These examples of Ischnura are from different parts of a dam, the upper lived amongst green waterplants, and the lower on dead wood.


A key to family groups of larval dragonflies and damselflies

1 slender larvae, with three terminal gills. Damselflies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (Suborder: Zygoptera)

1 robust larvae, without terminal gills. Dragonflies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (Suborder: Epiproctophora)

2(1) leaf-like terminal gills held flat and fanned out horizontally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Megapodagrionidae (page 171)

2 gills different in shape or orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3(2) sack-like terminal gills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diphlebiidae (page 168)3 leaf-like, or simple terminal gills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) gills divided into two parts by constriction . . . . . . . . . . . . . . . . . Isostictidae (page 169)4 gills complete, without constriction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5(4) larva small (14 mm) from swampy areas; prementum with ‘paraglossae’; gills short . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hemiphlebiidae (page 168)

5 larva usually not quite so small when fully-grown, prementum without ‘paraglossae’, gills distinctly leaf-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6(5) leaf-like gills with raised mid-vein or rib . . . . . . . . . . . . . . . . . Protoneuridae (page 172)6 leaf-like gills with mid-vein only slightly (if at all) raised . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7(6) gills shorter than last three abdominal segments . . . . . . . . . . Synlestidae (page 173)7 gills equal in length or longer than last three abdominal segments . . . . . . . . . . . . . . . . 8

8(7) secondary veins in gills perpendicular (at right angles to) mid-vein; labial palps with many long teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lestidae (page 170)

8 secondary veins in gills not perpendicular to mid-vein; labial palps simple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Coenagrionidae (page 167)

9(1) large larva (>40 mm); prementum with strong triangular, cleft, projection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Petaluridae (page 178)

9 smaller larva (usually <40 mm), prementum less distinct . . . . . . . . . . . . . . . . . . . . . . . . 10

10(9) prementum ladle-shaped, forming mask in front of larva’s face . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . corduliid/libellulid-like dragonflies (page 175)

10 prementum flat, folded under animal’s ‘chin’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

11(10) antennae with 4 segments, last segment enlarged and club-like; tarsi of at least foreleg and mid-leg with 2 segments . . . . Gomphidae and Lindeniidae (page 176)

11 antennae commonly with 5-7 segments; last segment rarely club-like; tarsi of all legs with 3 segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

12(11) rounded triangular lumps along the sides of all abdominal segments except 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Primitive dragonflies (page 179)

12 sharp backward pointing spines on some abdominal segments, including 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . aeshnid-like dragonflies (page 174)

perpendicular secondary veins branching secondary veins

TERMINAL GILLS (ZYGOPTERA)


Distinguishing characteristicsCoenagrionid larvae typically have slender,brown or green bodies, sometimes withdarker markings. Their gills are leaf-like andheld vertically. Mouthparts: prementum notcleft; labial palps simple; movable hook oflabial palp without setae, and multiplepremental setae. Fully grown larval lengthcan range between 13 and 30 mm fordifferent species.

Possible misidentificationsThe lestids appear similar, but usually haveperpendicular veins on their gills and amore slender overall appearance. Some ofthe Protoneuridae are also similar, but theyhave a distinct rib on their gills. Thesynlestids can be separated by their cleftprementum and their shorter gills.

Classification and distributionNine genera occur throughout temperateAustralia. They are often common animalswith extensive distributions. Ischnuraaurora, for example, also occurs in India andislands throughout the Pacific Ocean.

Habitat and ecologyOpportunistic species, such as Ischnuraaurora, have life spans that can be asshort as 8–10 weeks. This allows them tolive full lives even when the temporaryponds they live in dry up after a coupleof months.

Natural historyIt is not uncommon for adult dragonfliesand damselflies to be territorial, but somecoenagrionids are territorial as larvae whilestill in the water. Rather than defending amating ground, these animals appear to bedefending hunting grounds.

Adult females of some species in this groupcan occur in two distinct colour patterns,

one that resembles the males (andromorph)and another that is notably different(heteromorph). This strange arrangement isthought to protect the andromorph femalesfrom being overly harassed by males.

Suborder: Zygoptera, Family: Coenagrionidae

Typical coenagrionid larvae. Sometimesdamselfly larvae lose their gills, but they growback slowly, as they have on the green larva.

A mating pair of Ischnura heterosticta. The redand green male is holding the back of thefemale’s neck with a pair of claspers.


Distinguishing characteristicsDiphlebiid larvae have thick, brown bodiesand an overall ‘chunky’ appearance. Theirgills are sack-like with furry tips. The dorsalsurface of each abdominal segment has apatch of hairs. Mouthparts: prementumcleft; labial palps simple; four teeth on labialpalp; no palpal and no premental setae.Fully grown larval length is 14–24 mm.

Possible misidentificationsNo other damselflies in temperate Australiapossess sack-like gills. Old preservedspecimens of megapodagrionids may getpuffy gills and superficially look the samebut they lack the hairy back of thediphlebiids.

Classification and distributionOne genus, Diphlebia, with three species, isknown from mainland south-easternAustralia. This family was formerly groupedwith the family Amphipterygidae.

Habitat and ecologyTwo of the three known species occur inflowing waters, on the undersides of largerocks, while the third is more commonlyassociated with slow-flowing rivers anddetritus.

Natural historyAdults from this group of damselflies adopta very dragonfly-like pose when resting.However, their slender body and widelyspaced eyes distinguish them fromdragonflies.

Distinguishing characteristics This is a small damselfly larva around 14 mm long, which holds its simple gillsvertically. Mouthparts: prementum withcurved spines (‘paraglossae’) centrally above a shallow cleft; labial palps with manylong teeth.

Possible misidentificationsYoung lestids may appear superficially

similar with their many long teeth, labialpalps and similar gills, but the paraglossaementioned above are unique to theHemiphlebiidae.

Classification and distributionOnly one species, Hemiphlebia mirabilis, isknown. It is found in Victoria and a fewplaces in northern Tasmania but is fairlyuncommon.

Suborder: Zygoptera, Family: Diphlebiidae

Suborder: Zygoptera, Family: Hemiphlebiidae

Larval diphlebiids have ‘inflated’-lookingterminal gills. [Photo: John Hawking]


Suborder: Zygoptera, Family: Isostictidae

Habitat and ecologyHemiphlebia mirabilis occurs in ponds or temporary pools, usually in sandycatchments.

Natural historyThis endemic species is placed in what isthought to be a primitive family, and has avery similar form to fossils from thePermian (250 mya). The adult is small andmetallic green.

Distinguishing characteristicsIsostictid larvae have distinctly striped legsand dark to cream colouring. They holdtheir gills vertically and these are dividedinto two parts by a constriction.Mouthparts: prementum with protrudingfront margin, indistinctly cleft and withmore than one pair of setae; labial palpswith three teeth. Fully grown larval length is17–22 mm.

Possible misidentificationsPreserved specimens without gills could beconfused with a variety of other damselflylarvae.

Classification and distributionFour species from four genera occur inmainland south-eastern Australia. Thecommonest of these is Rhadinosticta simplex(formerly Isosticta simplex). The family isalso found in New Guinea and NewCaledonia.

Habitat and ecologyIsosticitids occur in flowing waters, amongstvegetation or leaf litter.

Rhadinosticta simplex is a striped larva, withdivided gills, a characteristic that defines thefamily Isostictidae. [Photo: Karlie Hawking]

Hemiphlebia mirabilis. [Photo: John Trueman]


Distinguishing characteristicsLestid larvae are slender, brown or green, withlong leaf-like gills that are held vertically.The smaller veins of the gills appear perpen-dicular to the mid-vein. Often there is a darkband midway down the gill. Mouthparts:prementum distinctly cleft; labial palps withmany long teeth, forming a basket of ‘teeth’when closed; movable hook of labial palpwith 2 setae; 7–8 pairs of premental setae.Fully grown larval length is 21–30 mm.

Possible misidentificationsSee Coenagrionidae (page 167).

Classification and distributionOnly one genus, Austrolestes, is known from

south-eastern Australia and is widelydistributed.

Habitat and ecologyLestids typically occur in slow-flowingwaters and are often found around waterplants.

Natural historySome adult damselflies from this family willimmerse themselves totally while laying eggson water plants. If the male is still guardingthe female from other males, both animalswill submerge. Adult damselflies can remainsubmerged for around fifteen minutes andsometimes perish underwater after layingtheir eggs.

Suborder: Zygoptera, Family: Lestidae

As these mating pairs of Austrolestes cingulatus age, their blue colours are replaced with green,gold and copper. The male holds onto his mate, often staying attached to her while she lays eggs.

Austrolestes sp. slowly stalks its prey, in thiscase a small midge larva.

With mouthparts unextended, Austrolestes analisshows its distinctive basket of interlocking teeth.


Distinguishing characteristicsLarvae are usually brown with light or darkpatterns. Their gills are broad and heldhorizontally. Mouthparts: prementum cleft;no premental setae. Fully grown larvallength of Griseargiolestes is 15 mm;Austroargiolestes is 23 mm.

Possible misidentifications No other damselfly larvae hold their gillsflat like the megapodagrionids.

Classification and distributionTwo genera occur commonly in mainlandsouth-eastern Australia, Griseargiolestes andthe slightly larger Austroargiolestes.

Habitat and ecologyThe Megapodagrionidae occur mainly inboggy, swampy areas.

Natural historyThe commonest megapodagrionid fromsouth-eastern Australia is Austroargiolestesicteromelas. Larvae are difficult todistinguish and many of the members ofthis family are only known as adults.

Suborder: Zygoptera, Family: Megapodagrionidae

Austroargiolestes sp. makes its home in swampy areas.

Austroargiolestes sp. shows its horizontal fan ofgills, typical of megapodagrionids.


Distinguishing characteristicsProtoneurid larvae are usually brown withcontrasting light or dark patterns. Their gillsare held vertically and have a distinct ‘rib’.Mouthparts: prementum not cleft; labialpalps with three teeth and some setae;movable hook of labial palp without setaeand only one pair of setae on the prementum.Fully grown larval length is 25–28 mm.

Possible misidentificationsSee Coenagrionidae (page 167).

Classification and distributionOne species, Nososticta solida, occurs intemperate Australia.

Habitat and ecologyNososticta solida occurs in streams andrivers in areas of slow flow. Often foundamongst water plants.

Natural historyThe adults of this family are extremelyslender-bodied and usually flaunt black-orange or black-yellow colour patterns.

Suborder: Zygoptera, Family: Protoneuridae

The larva of Nososticta solida has its gillsreinforced with a longitudinal rib. [Photo: John Hawking]

Adult megapodagrionids are common in the vegetation around swamps in early summer.


Distinguishing characteristicsSynlestid larvae are usually brown with lightor dark patterns. Their gills are short andtheir antennae long with darker segmentsclose to the head and lighter bands at theends. Fully grown larval length is 25–28 mm.

Possible misidentifications See Coenagrionidae.

Classification and distributionTwo genera of this endemic family arefound in south-eastern Australia.Episynlestes occurs in rainforests in northernNew South Wales, while the more-commonSynlestes ranges throughout the area.

Habitat and ecologySynlestids occur in a variety of habitats,usually with flowing water.

Natural historyThe commonest members of this family are

from the genus Synlestes. The larvae arestick-like and hold their bodies with adistinctly recurved posture. This mixture of colour and posture makes them perfectlycamouflaged amongst woody debris andwater plants. Effective camouflage helps themsneak up on prey, but also makes them muchless visible to larger predators such as fish.

Suborder: Zygoptera, Family: Synlestidae

Synlestes weyersii arches its abdomen in a scorpion-like manner, adding to its stick-likeappearance.

An adult Synlestes weyersii. Female odonatestend to have a bulbous end to their abdomen,while males often end in a pair of claspers.


Aeshnid-like dragonflies (Suborder: Epiproctophora, Families: Aeshnidae and Telephlebiidae)

Distinguishing characteristicsAeshnid larvae come in a variety of colours,including reds, greens and browns, oftenwith mottled patterns. They have large eyesand a stocky body. The abdomen usually hassharp backward pointing spikes on its sides(at least on segment 9). Mouthparts:prementum flat, with simple labial palpsending in a large movable hook and onetooth. Their antennae have 5–7 segments.Fully grown larval length is 30–40 mm(though some genera are slightly smaller).

Possible misidentificationsSee Primitive dragonflies (page 179).

Classification and distributionThese two families were formerly groupedas the Aeshnidae, but they have now beenseparated. The Aeshnidae have a two-pronged central point to their abdomen,while the Telephlebiidae have a single point.True aeshnids often have setae on the dorsalsurface of their labial palps. Both familiesare widely distributed throughout south-

eastern Australia. Despite the recurrence ofthe word ‘aeshna’ in many of the genericnames, most of the animals from this groupnow belong with the Telephlebiidae. Thetwo families include 10 genera and 25species from south-eastern Australia.

Habitat and ecologyThese large predators inhabit both fast-moving and stagnant waters. They can befound on a range of substrates, from cobbles to water plants. The generaTelephlebia and Antipodophlebia can befound in damp litter near waterways ratherthan in them.

Natural historyThe aeshnid-like odonates are some of thelargest invertebrate predators in streams.They maintain this role as adults. Adultssport dull colours and are rarely still,spending most of their time on the wing,hunting and defending their territoriesagainst other dragonflies. Immature larvaecan be dramatically striped.

Aeshna brevistyla has a striped pattern, and thecentral prong at the end of its abdomen has twopoints. This character separates the Aeshnidaefrom the Telephlebiidae.

Notoaeschna sagittata is one of the spikieraeshnid-like larvae.


Corduliid/libellulid-like dragonflies (Suborder: Epiproctophora,Families: Austrocorduliidae, Cordulephyidae, Synthemistidae,

Gomphomacromiidae, Hemicorduliidae, Urothemistidae and Libellulidae)

Distinguishing characteristicsLong thin legs give most of the members ofthis group a ‘spidery’ appearance. They arerounded animals, green to brown, oftenwith mottled patterns. Many of themcultivate a layer of silt and algae over theirbacks. They have thin antennae with morethan four segments. Mouthparts:prementum with labial palps forming aladle-like structure folded under the head;labial palps may have a convoluted edge orbe simple and with or without setae.

Fully grown larval length is highly variable.Nannophya australis, from New South Walesis around 8 mm while some of the largersynthemistids are around 26 mm long.

Possible misidentifications This family group is very distinctive, anddifficult to misidentify.

The Tasmanian synthemistid Synthemiopsis is asimilar shape to the corduliids and libellulids,but is a lot hairier.

Hemicordulia tau is a sit-and-wait predator that lurks amongst the sediment and algae at thebottom of ponds.


Classification and distributionThis diverse group of families has had quite a turbulent history and, in the past,species have been included in Corduliidae,Synthemidae and Libellulidae. There arearound 29 genera in south-eastern Australia,the commoner ones being Hemicordulia andEusynthemis.

Habitat and ecologyThis large group has representatives thatoccur in all aquatic habitats, but most of themare found in slow-flowing to stagnant water,amongst detritus, silt and water plants.

Natural historySome members of this group areopportunists, capable of colonisingtemporary water and going through severalquick generations, before the waters dry up.One such species, Hemicordulia tau, is alsoknown to form large swarms of adultsaround bogs or wetlands.

While all big red dragonflies (in temperateAustralia) are from the Libellulidae, not alllibellulid dragonflies are big and red. This isa large and diverse family; the adults comein a variety of colours and patterns so thereis no easy rule for recognising all of them.

Distinguishing characteristicsGomphid larvae are stocky, and brown,green, or lighter coloured. Sometimes theywear a film of fine detritus. Their antennaeare 4-segmented and club-shaped, with thefinal segment enlarged. The pro- and meso-tarsus have two segments (most otherdragonflies have three) and this is thoughtto make the legs more robust for diggingthrough silt. Mouthparts: prementum flat,without cleft; labial palps simple, without

setae. Lindeniids have distinctly roundbodies. Fully grown larval length is 20–30 mm.

Possible misidentificationsSome of the Gomphidae may superficiallyresemble aeshnid-like larvae, but theirantennae are always 4-segmented andtruncated while their fore- and mid-tarsi arealways 2-segmented.

An adult Procordulia jacksoniensis spends mostof its time hunting above the waters that it grewup in.

Nannophya dalei is one of Australia’s smallestdragonflies, with a wingspan usually less than40 mm.

Suborder: Epiproctophora, Families: Gomphidae and Lindeniidae


Classification and distributionThe Lindeniidae was formerly part of theGomphidae. One species, Ictinogomphusaustralis, occurs in mainland temperateAustralia. It is found more commonly northof Sydney. The family Gomphidae is adiverse and widely distributed group ofdragonflies found throughout temperateAustralia. Ten species from three genera are known from temperate Australia, thecommonest genus encountered isAustrogomphus.

Habitat and ecologyThese dragonflies inhabit sections of rivers

with slower flows, often in areas where thesubstrate is covered with detritus. Somespecies occur in lakes.

Natural historyGomphids are one of the few groups ofdragonflies that can emerge from ahorizontal surface. Most dragonflies climbup vertical sticks or reeds which allows themto ‘fall’ from their larval skin.

Most gomphid adults are black and yellow.They are ‘perchers’, surveying theirterritories from a lookout, which they willreturn to after reconnaissance flights andbouts of hunting.

Austrogomphus guerini crawls from Lake Pedder, and emerges from its larval skin. A gomphid isthe only odonate that doesn’t need to hang from something when it emerges.


Distinguishing characteristicsThe petalurids are the largest dragonflies inAustralia. Larvae can be as long as 50 mm.Their abdomen lacks armouring and theyhave long antennae on an angular head.Mouthparts: prementum flat with a clefttriangular extension; simple labial palps.

Possible misidentifications Large specimens are difficult to mistake foranything else, but care should be taken withsmaller specimens.

Classification and distributionTwo species, Petalura gigantea and Petaluralitore, are known from northern New SouthWales. One species, Petalura hesperia, isfound in Western Australia and anotherlarger species, Petalura ingentissima, occursin tropical Queensland. This group is asworthy of the title ‘primitive dragonflies’ asthe next group, but they have been keptseparate because of their size. The closestrelatives of Petalura are found in SouthAmerica.

Habitat and ecologyPetalurid larvae are semi-aquatic burrowers;they live in holes in swampy ground orbeside streams.

Natural historyThe petalurids are considered to be a stronglink to the original dragonflies of theCarboniferous period, sharing many of thecharacteristics of ancient dragonflies,including their size. Petalura gigantea is thesecond largest dragonfly in temperateAustralia. Petalura ingentissima, fromtropical Queensland, is the largest inAustralia, with a wingspan of up to 175 mm.

The world’s largest odonate is Megaloprepuscoerulatus, a damselfly from Central America,with a reported wingspan of 190 mm.

Giant dragonflies (Suborder: Epiproctophora, Family: Petaluridae)

An adult male ‘petal tail’ (Petalura gigantea).Suitable swamp habitats for these animals arebecoming rarer. [Photo: Caroline Dearson,Sydney Catchment Authority]

Petalura gigantea leaves its burrow and climbsup a nearby reed before emerging as an adult.The claws of this empty skin are firmly stuck tothe reed, allowing the adult to pull itself free.


Distinguishing characteristicsThe larvae of primitive dragonflies haveprominent, blunt, triangular projectionsdown both sides of the abdomen. They areoften dark coloured with protrusive eyes.Mouthparts: prementum flat; without setae.Fully grown larval length is 30–40 mm.

Possible misidentificationsThe aeshnid-like dragonflies can appearsimilar, but they have sharp, stronglybackward pointing spines along the sides oftheir abdomens, rather than blunttriangular projections.

Classification and distributionTwo species of Austropetaliidae are found inNew South Wales, both from the genusAustropetalia. The Tasmanian Archipetaliaauriculata is the only species in the familyArchipetaliidae. Formerly these species havebeen placed in the families Petaliidae andNeopetaliidae.

Habitat and ecologyMost of the larvae from this group are semi-terrestrial, living in splash zones orunder damp logs at the sides of streams.Older larvae can be found slightly further

from permanent water.

Natural historyAll of these dragonflies are strong climbersand can be found several metres off theground hanging from trees or rock faces,when they are getting ready to emerge.They are also renowned for ‘playing possum’and can pretend to be dead indefinitely.Their diet includes most of the invertebratelife that can be found under logs and in thesplash zones of waterfalls.

Primitive dragonflies (Suborder: Epiproctophora, Familes: Archipetaliidae and Austropetaliidae)

Archipetalia auriculata has spots and colouralong the front margin of its wings.

The primitive dragonfly larva, Archipetaliaauriculata, is semi-terrestrial.

This emerging Archipetalia auriculata has justspent two years as a larva.

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Characteristics of adultsAdult stoneflies are 5–60 mm long, with asoft, flattened body and four membranouswings folded above the body. Their colour isusually grey or brown, making them lookinconspicuous, but some eustheniids havebright red, orange and black markings.Adult stoneflies are not very good fliers andtherefore can be found close to creeks andrivers on surrounding vegetation where theymate before laying their eggs in the water.

Most adults emerge around spring orautumn and can live for up to a month.During this time they feed on organic mattersuch as rotten wood, lichen and algae.

Characteristics of nymphsAll stonefly nymphs are aquatic. They looksimilar to adults but have wing pads insteadof wings. As with dragonflies and mayflies,the size of a stonefly nymph and its wingpads increases with every stage of

Stoneflies (Order: Plecoptera)

Stoneflies are a small, relatively primitive, group of insects. The nymphs are sensitiveto water quality and are abundant in alpine streams.

GENERALISED STONEFLY NYMPH GENERALISED STONEFLY ADULT

cercicerci

antennae

wing

antennae

head

wing pads

position of gills(Eustheniidae)

position of gills(Gripopterygidae,Austroperlidae)

Stoneflies l 181

development. Stoneflies do not undergo acomplete metamorphosis and the adultsemerge from mature larvae after they havecrawled from the water on twigs or stones.Nymphs and adults of most species, have a3-segmented tarsus, long antennae and twocerci. Gripopterygid and austroperlid nymphshave gill tufts at the end of the abdomen.Nymphs use these gill tufts to breathe underthe water. Most nymphs feed on detritus,but some species are carnivorous.

ClassificationThere are around 200 species of Australianstonefly belonging to four families(Eustheniidae, Austroperlidae,Gripopterygidae and Notonemouridae)which occur only in the southernhemisphere. Of the 26 Australian stoneflygenera, 25 are endemic, while Notonemourais also found in New Zealand.

Crypturoperla, an endemic Tasmanian, hasinconspicuous gills but can be recognised bythe tubercles on its abdomen.

A nymph of Trinotoperla showing a tuft of gillsat the tip of its abdomen.

Adult stoneflies are usually inconspicuous, but eustheniids have bright red, orange and blackmarkings.


Stoneflies as food for fish.In alpine and semi-alpine streams stonefliescan occur in very large numbers. Fly fishershave long noticed that both nymphs andadults are very attractive food for trout andsome species of native fish. Fish often feedon adult stoneflies as they run or ‘skim’ onthe surface of the water. Many types ofartificial ‘fly’ are designed to imitate stoneflieslanding or falling on the water surface.

Fossil recordsThe first fossil record of stoneflies can bedated back to the early Permian period,approximately 290 mya. Modern families ofstoneflies from the northern hemispherecan be identified from Baltic amber datedback to 38–54 mya.

DrummingAdult stoneflies from the northernhemisphere communicate using‘drumming’—a beating and rubbing oftheir abdomen on the ground to createvibrations. Usually a male initiatesdrumming and then, if he is recognised, afemale drums an answer. Drumming isthought to help males and females to findeach other. The drumming frequencies arespecies specific and can be picked up byanother insect eight metres away!

Drumming is, as yet, unknown in Australianstoneflies.

The origin of flightThe behaviour of stoneflies can shed lighton one of the theories of the origin of flightamong insects. Some fossil arthropods havelarge gill plates on their body (like somemayflies). These gills could have served asprototypes to modern wings. How theseweak gill plates were first used for flightremains a mystery, but they may have beenused the same way stoneflies use their wingstoday. Many modern stoneflies ‘skim’ on thesurface of the water using hairs on their legsto skate, while their wings propel them likehovercraft. Their wings do not require asmuch power for skimming as they do forflight. While many scientists think thatskimming and the loss of flight aresecondary in stoneflies (similar to thecomplete loss of flight by penguins),skimming on the water may provide an insight into how primitive wings wereused by insects.

Environmental significanceStoneflies are very sensitive to water quality.The number of species occurring in aparticular stream is sometimes used as animportant indicator of the stream’s health.

Key to families of stonefly nymphs

1 no external gills at tip or sides of abdomen . . . . . . . . . . Notonemouridae (page 186)1 external gills at tip or sides of abdomen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2(1) external gills on side of the abdomen; size often greater than 30 mm for fully grown nymph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Eustheniidae (page 184)

2 external gills at tip of abdomen only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3(2) two long cerci present at the tip of the abdomen; numerous external gills form tuft at the tip of the abdomen; gills can sometimes be drawn inside the body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gripopterygidae (page 185)

3 short cerci; three or five external gills only; genera Acruroperla and Crypturoperla have inconspicuous gills but can be recognised by tubercles on the abdomen . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Austroperlidae (page 183)

Stoneflies l 183

Distinguishing characteristicsAustroperlid nymphs can be recognised bythe extended corners of their first thoracicsegment, a long cylindrical abdomen, shortcerci and a small number of gills. The size ofmature nymphs varies from 8 to 30 mm.

Possible misidentificationsAcruroperla and Crypturoperla nymphs cansometimes be confused with notonemourids.Notonemourids lack dorsal tubercles on theabdomen.

Classification and distributionThis small family includes eight species.Five genera are known from south-easternAustralia: Acruroperla, Austroheptura,Austropentura, Tasmanoperla andCrypturoperla. Tasmanoperla andCrypturoperla occur only in Tasmania.

Habitat and ecologyAustroperlid nymphs are often associatedwith woody debris or can be found in theturbulent waters in the middle of thechannels of alpine and semi-alpine streams.They feed on detritus and softened wood.

Natural historyEggs are laid in autumn and nymphs spendaround two years in the water beforebecoming adults. Most nymphs are ratherslow moving.

Family: Austroperlidae

Most austroperlid nymphs have long cylindricalabdomens, short cerci and a small number ofgills.

The genus Tasmanoperla is endemic to Tasmania.


Distinguishing characteristicsThis family includes the largest and mostcolourful stoneflies in Australia. Thenymphs, which can reach up to 60 mm inlength, can be easily recognised by five or sixpairs of beaded gills on the sides of theirabdomen and long robust cerci.

Possible misidentificationsEustheniids are very distinctive and aredifficult to confuse with any other group.

Classification and distributionThere are three eustheniid genera inAustralia: Cosmioperla, Eusthenia andThaumatoperla.

Habitat and ecology

The nymphs are sensitive to low levels ofdissolved oxygen. Many taxa require coolerwater temperatures and are thereforerestricted to fast-flowing alpine creeks withpebble and cobble beds.

The nymphs of all eustheniids are voraciouspredators and have a pair of sickle-likepiercing jaws. They can crawl rapidly understones in search of their prey, which consistsmainly of other aquatic invertebrates,sometimes even including smaller stoneflies.

Natural historyIt takes three or four years for eustheniids to complete their lifecycle. This is due totheir large size and the alpine temperatures,which slow down the metabolic rate ofnymphs. If disturbed, nymphs drop fromstones, curl and let the water current carrythem away from the danger. They can alsoswim with fish-like movements by bendingthe abdomen.

Family: Eustheniidae

Eustheniids are the largest and most colourful stoneflies in Australia.

Eustheniid nymphs have gills on the sides of theabdomen.

Stoneflies l 185

Distinguishing characteristicsAll gripopterygids have a gill tuft at the endof their abdomen. Their size ranges from 5to 30 mm.

Possible misidentificationsA gripopterygid can be confused with anotonemourid if its anal gill tuft is retracted.If you are identifying dead specimens, thegripopterygid’s tuft can sometimes be gently squeezed out with forceps. Livegripopterygids will usually have their gillsexposed and will often wave them throughthe water with a dog-like tail wag.

Classification and distributionThese are the most common stoneflies inAustralia and Gripopterygidae has thelargest number of species in Australia.Genera include: Kirrama (only in northernQueensland), Cardioperla (only inTasmania), Dundundra (only in northernQueensland), Nescioperla (only in northernQueensland) Leptoperla, Newmanoperla,Riekoperla, Neboissoperla, Illiesoperla,Eunotoperla and Trinotoperla.

Two species of adult gripopterygid arewingless. One is found only on top of MtKosciuszko and the other in a small tricklenear the top of Mt Donna Buang in Victoria.

Habitat and ecologyGripopterygids can be found in all kinds ofcreeks and rivers at any altitude. Somespecies occupy the middle of the channelwhile others can be found only at the bank.Some species prefer stones as a habitat,while other live among aquatic plants.

The gripopterygid diet is diverse. Somespecies eat only detritus or algae from thesurface of submerged leaves, wood and rock.Other species switch to a carnivorous diet ata later stage of development.

Natural historyThe lifecycle of gripopterygids is quitevariable. Commonly it takes around one yearfor a nymph to become an adult. Emergencetakes place in autumn and spring.

Family: Gripopterygidae

The genus Leptoperla has slender nymphs withrelatively long legs.

Some species of Riekoperla have a dorsal rowof spines along the centre of their abdomen.

Gripopterygid adults are a common sight nearmountain streams in autumn and spring.


Distinguishing characteristics Notonemourid nymphs can be recognisedby the absence of external gills. Their sizeranges from 7 to 12 mm.

Possible misidentificationsSee Gripopterygidae.

Classification and distributionThe six genera within the familyNotonemouridae are Notonemoura,Austrocercella, Austrocerca, Austrocercoides,Kimminsoperla and Tasmanocerca.

Habitat and ecologyNotonemouridae can be found on rocksurfaces and medium-size wood debris insmall alpine streams and even trickles.Some species can be collected from thestagnant waters of alpine swamps and pools.

Natural historyRelatively little is known about the lifecycleof Australian notonemourids. They can

emerge throughout the year but it is morelikely to find adults in late spring, summerand autumn.

For stoneflies, notonemourids aresurprisingly active. They can move quite fast on the surface of rocks. Some specieshave an enlarged femur of the hind legs,and the adults tend to run and jump ratherthan fly.

Family: Notonemouridae

Notonemourid adults are very agile. Somespecies can jump.

The absence of external gills is a characteristicfeature of notonemourid nymphs.

The body of a notonemourid nymph is oftendensely covered with setae that trap silt andfine sand.

Caddisflies l 187

Caddisflies (Order: Trichoptera)

The caddisflies are an extremely diverse group, including some of freshwater’s mostfearsome predators, as well as docile algal grazers and leaf chewers.

antennae

maxillarypalps

abdominalpro-legs

abdomen thorax

metanotum

mesonotum

pronotum

head

fore trochantin

foreleg

hook holdsanimal incase

lateral humps

portable case

mid-leg

hind leg

metasternummesosternum

prosternum

legswing

ADULT CADDISFLY

CADDIS LARVAE


Characteristics of an adultAdult caddisflies superficially resemblemoths. This is not surprising as they arequite closely related. Unlike moths, however,their wings rarely have scales and arecovered with hairs instead. The mouthpartsof caddisflies are long, paired and straightinstead of long, fused into a tube and coiled,like a moth’s. The antennae of many caddis-flies are also very long. Adult caddisflies cansometimes be active during the day, butlarger numbers are often seen in the eveningclose to the water bodies where their larvaeoccur. Most adult caddisflies are attracted tolight, and this tendency makes it even morelikely that they are mistaken for moths.

Characteristics of a larvaCaddis larvae can be broken into two simplegroups: those that live in portable cases(cased caddis), and those that are caseless orfree-living. All caddis larvae have the frontpart of their bodies hardened or sclerotised,while the abdomen remains pale and fleshy.They also have a pair of hooks at the end oftheir abdomen. Cased caddis larvae usethese hooks to hold on to their cases, whilefree-living larvae use them to grapple thestream bed and drag themselves swiftlybackwards to escape from predators. Inthose families with portable cases, the caseprotects the soft abdomen of the animalfrom predators. If attacked or surprised, thecaddis larva can withdraw into the case and

wait for danger to pass. Free-living caddislarvae lack these portable cases, but canbuild retreats from thin strands of silk fixed to rocks. Often they will return tothese after a day foraging. Some structuresincorporate nets for catching food—a bitlike a spider’s web—while others are mainlyused as protection when the animal beginsto pupate. Most caddis larvae have silkglands that stretch the length of their body.These are sufficient to constantly repair andrebuild their portable cases or fixed retreatsif they are damaged or washed away.

ClassificationThere are 26 families and around 500species of caddisfly in Australia. One ofthese families (Chathamiidae) is marine,and therefore not covered by this book,while the larvae of another family(Stenopsychidae) haven’t been recorded yet.Most of the species of Trichoptera found inAustralia are endemic, and two families,Plectrotarsidae and Antipodoeciidae, aretotally endemic. The families covered in thistext are: Antipodoeciidae, Atriplectididae,Calamoceratidae, Calocidae, Conoesucidae,Ecnomidae, Glossosomatidae, Helicophidae,Helicopsychidae, Hydrobiosidae,Hydropsychidae, Hydroptilidae, Kokiriidae,Leptoceridae, Limnephilidae,Odontoceridae, Oeconesidae,Philopotamidae, Philorheithridae, Plectro-

An adult leptocerid showing its long antennaeand maxillary palps.

A larval hydroptilid caddis has a small pair ofhooks at the end of its abdomen to grip theinside of the case.

Caddisflies l 189

tarsidae, Polycentropodidae and Tasimiidae.The Dipseudopsidae and Psychomiidae havebeen left out as they are mainly found intropical Australia.

Carpenters, stonemasons and spinnersCased caddisfly larvae use a variety ofbuilding materials for their homes. Theirchoice of building materials depends on thespeed of the water, the materials available,and the particular preferences of the speciesof caddisfly. For example, many of theleptocerids live in slow-flowing habitats,where there is a lot of plant matteravailable, so they tend to construct casesfrom sticks and aquatic plants.Glossosomatids tend to occur in faster-flowing streams, with gravel and sand, sothis is what they use to construct theircases. All caddis larvae use silk to buildtheir cases and some caddises constructcases using only silk. This gives the cases a‘spun’ appearance. The silk is spun from anorgan on the underside of the head (thelabium) and can vary in colour from creamand golden, to dark brown or black.

Environmental significanceMany caddisfly larvae are quite sensitive towater quality, and for this reason, they areused worldwide to assess river health.However, some leptocerids andhydropsychids can tolerate quite degradedsites, so their presence should not be used asan absolute indicator of ‘good’ water quality.It is safer to use the presence of a diverserange of caddis larvae as an indicator ofstream health.

Glossosomatids cluster together before pupating. They form their cases from hard-wearing sandand gravel which will withstand fast-flowing water and the odd rolling pebble.

The caddis larva Oecetis (Leptoceridae) useslengths of water milfoil leaf to construct its logcabin-like case.


Key to families of caddis larvae*

1 abdomen swollen, thicker than thorax; construct a purse-shaped case of silk, sometimes with sand or algae incorporated. . . . . . . . . . . . . . . . . Hydroptilidae (p. 201)

1 abdomen not noticeably swollen or thicker than thorax; case if present, not purse-shaped . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2(1) mesonotum and metanotum each with one pair of small sclerites; abdominal pro-legs partially fused and sclerotised; construct a small, dome-shaped sand case incorporating a variety of particle sizes . . . . . . . . . . . . . . . . . Glossosomatidae (p. 197)

2 mesonotum and metanotum with more or less sclerotisation than above; pro-legs either totally fused to form a false 10th segment, or totally separate . . . . . . . . . . . . . . 3

3(2) larvae free-living/caseless, or constructing a retreat attached to the substrate; first abdominal segment without lateral/dorsal humps; well-developed abdominal pro-legs with conspicuous claws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 larvae usually found inside a portable case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4(3) all three thoracic segments with sclerotisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 only the first thoracic segment with sclerotisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5(4) abdominal gills present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydropsychidae (p. 200)5 abdominal gills absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ecnomidae (p. 196)

6(4) labrum membranous and pale, front edge wider than back . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Philopotamidae (p. 207)

6 labrum sclerotised and with front edge similar or less wide than back . . . . . . . . . . . . 7

7(6) foreleg modified, either with pincers, or with the femur broadened and armed with thick spines; fore trochantin small . . . . . . . . . . . . . . . . . . . . Hydrobiosidae (p. 198)

7 foreleg simple without pincers and with femur not broadened; fore trochantin large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Polycentropodidae (p. 210)

8(3) larvae construct a coiled case of sand grains superficially resembling a snail shell; claws on abdominal pro-legs modified to form a comb-like structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Helichopsychidae (p. 198)

8 larval case uncoiled, claws on abdominal pro-legs usually unmodified . . . . . . . . . . . 9

9(8) head long and very small relative to thorax, thin and without visible joins; pronotum with two pairs of sclerites on anterior half, posterior half without sclerites and retractable into mesonotum . . . . . . . . . . . . . . . . . . . . . . . . . . . Atriplectididae (p. 192)

9 head not reduced, broad with visible joins: pronotum completely sclerotised . . . . 10

10(9) middle leg with tibia and tarsus fused . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1110 middle leg with tibia and tarsus not fused . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

11(10) foreleg with tibia and tarsus fused; two main sclerites on the underside of the head completely separated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kokiriidae (p. 202)

11 foreleg with tibia and tarsus not fused; two main sclerites on the underside of head not completely separated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Philorheithridae (p. 208)

12(11) prosternum with a single thick, curved, horn-like spine . . . . . . . . . . . . . . . . . . . . . . . . . . 1312 prosternum without thick, curved, horn-like spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

13(12) mesonotum with three pairs of sclerites; underside of first abdominal segment with three pairs of setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plectrotarsidae (p. 210)

13 mesonotum with a single large sclerite; underside of first abdominal segment with more than three pairs of setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Limnephilidae (p. 205)

Caddisflies l 191

Key to families of caddis larvae (contd.)

14(12) metasternum with two or more setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1514 metasternum without setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

15(14) antennae often long; pronotum usually with few setae on the anterior; if numerous setae, then also with sclerites on the metasternum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leptoceridae (p. 203)

15 antennae minute; pronotum with a collar of setae; metasternum with setae but never with sclerites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calocidae/Helicophidae (p. 194)

16(14) abdomen with a conspicuous fringe of fine setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1716 abdomen without a conspicuous fringe of fine setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

17(16) head capsule with a prominent ridge (carina) around the edge of the dorsal side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Oeconesidae (p. 207)

17 head without a prominent ridge around the edge of the dorsal side. . . . . . . . . . . . . . 18

18(17) case built from sand/gravel; hind legs and forelegs of similar size; eyes protruding when viewed dorsally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tasimiidae (p. 211)

18 case built from two pieces of leaf; hind legs about twice the length of the forelegs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calamoceratidae (p. 193)

19(16) prosternum with large sclerite or sclerites . . . . . . . . . . . . . . . . . Odontoceridae (p. 206)19 prosternum pale and membranous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

20(19) underside of head capsule has the two major plates (sclerites) separated posteriorly; the sclerite between these is usually square or rectangular . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Conoesucidae (p. 195)20 underside of head capsule with the two major plates almost touching posteriorly,

and with the plates between them triangular in shape . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

21(20) pronotum with a sharp, blade-like collar . . . . . . . . . . . . . . . . . Antipodoeciidae (p. 192)21 pronotum without a sharp, blade-like collar . . . . . Calocidae/Helicophidae (p. 194)

*modified from Dean, St. Clair and Cartwright 1995

HEAD – VENTRAL HEAD – DORSAL

ventralapotome

eye

frontoclypeus

silk organ/labium

labrum labrum

mandible

antennaantenna


Distinguishing characteristicsThe larvae of this caddis have a distinctiveblade-like ridge along each side of thepronotum. The ridge is also generallyknobbly or beaded. They are about 5 mmlong and construct a small case from sand.

Possible misidentificationsAntipodoeciids are relatively rare, so manyquestionable identifications may in fact beCalocidae/Helicophidae or Conoesucidae.

Classification and distributionThis small family includes only one speciesin the genus Antipodoecia. It is relatively rareand occurs only on the east coast ofmainland Australia.

Habitat and ecologyVery little is known about this group, butlarvae seem to occur in small streams withfairly good water quality.

Distinguishing characteristicsThese larvae can be fairly large (8–18 mm).They can be distinguished by their caseswhich are constructed from sand and finersediments and are almost square in cross-section with a groove along the length of theupper surface. The larvae themselves havedistinctly elongate heads, which appearseamless and are retractable into the thorax.Adults from this family have very longantennae, and look a bit like adult

leptocerids, but are less common.

Possible misidentificationsAtriplectidids are very distinctive andtherefore difficult to misidentify.

Classification and distributionAtriplectides dubius is the only recognisedspecies of Atriplectididae in temperateAustralia. It occurs quite commonly alongthe east coast of mainland Australia and

Antipodoecia sp. shows the distinctly beadedcarina on its pronotum.

The groove on the upper surface of larval atriplectidid cases is distinctive, but its function isuncertain. Both the legs and head of Atriplectides are specialised for feeding on dead invertebrates.

Family: Antipodoeciidae

Vulture caddis (Family: Atriplectididae)

Caddisflies l 193

Tasmania. This family is also found in theSeychelles Islands and South America.

Habitat and ecologyAtriplectides occurs quite commonly incoastal areas. Caddises from the familyAtriplectididae are scavengers that fossickaround in slow waters and silty habitatswhere they feed on decaying animal andplant material.

Natural historyAtriplectides’ strange head shape allows it toscavenge the bodies of other dead animals.Once it has made a large enough hole for itshead, it can get to the soft flesh inside acarcass without wasting effort on cuttingthrough any more of the leathery skin. Thisis a similar tactic to that used by vultures.

Distinguishing characteristicsBoth the larvae and the cases of this familyare quite distinctive. The cases are madefrom two leaf fragments, the dorsal leafbeing slightly larger than the ventral. Casescan be as long as 20 mm and are usuallyfairly wide, but distinctly flattened. Thelarva has a fringe of hairs around the edgeof its abdomen, and its hind legs are aroundtwice the length of its forelegs. Thepronotum is also distinctive when vieweddorsally, with recurved sides.

Possible misidentificationsAlthough the cases are quite distinctive,some leptocerids (Lectrides and Westriplectes)build a similar case, so inspect the larvaethemselves for an accurate identification.

Classification and distributionAnisocentropus is the only calamoceratidgenus found in Australia. The family occursin other parts of the world, including thenorthern hemisphere. Ten species occur inAustralia, and three of these in south-eastern Australia, but they cannot bedistinguished from one another as larvae.Both larvae and adults are quite common.

Habitat and ecologyCalamoceratids feed on decaying plantmaterial and are usually found in stillsections of slow-flowing lowland rivers,swamps and lakes.

Natural historyThe wings of adult calamoceratids are oftendecorated with highly contrasting patterns.This distinguishes them from most othercaddisflies, which normally sport mutedgrey colours and softer patterns.

The overlapping leaves in the calamoceratid’scase obscure the animal’s head from predators.From above it resembles a slow moving leaf.

Adult calamoceratids often have simple buteye-catching patterns on their wings.

Sleeping bag caddis (Family: Calamoceratidae)


Distinguishing characteristicsThe larvae from this pair of families vary insize (6–14mm) and appearance. Theyconstruct a wide range of case types usingeither plant matter, sand, silk, or all of these.Their distinguishing characteristics are quitesubtle, and include minute antennae, atriangular ventral apotome (oftenunpigmented in the posterior half), a fullybut weakly sclerotised mesonotum, and ametanotum with hairs but very littlesclerotisation. Several genera have adistinctive fringe of long dark hairs aroundthe front edge of the pronotum, but thisdoes not hold true for the entire group.

Possible misidentificationsCalocid/helicophid larvae can easily beconfused with a range of other caddisfamilies, especially when earlier instars arebeing identified.

Classification and distributionThese two families are represented inAustralia by around 15 described genera.All but one of these is found in south-eastern Australia. The families also occur in New Zealand and South America.

Habitat and ecologyThe larvae of the more common species canbe found in the slower sections of clear,swift-moving streams in forested areas.They often live around areas that accumulatedecaying plant matter. Two species havebeen recorded from terrestrial habitats inTasmanian rainforests. The Calocidae andHelicophidae are thought to feed ondecaying plant material and micro-algae.

Natural historyThese two families include a wide range ofspecies that can be found in a diverse range

Families: Calocidae/Helicophidae

Caenota plicata is a very common and widespread calocid. Its ‘shingle’ case pops up in a variety ofstreams. The collar of long hairs on the front edge of the pronotum is a character shared by manycalocids and helicophids.

Caddisflies l 195

of habitats, from small alpine swamps, tomedium-sized, forested streams. They areusually associated with good water quality.Some of the most magnificent casesamongst caddis larvae belong to members

of this group, including the extremely longsilk and sand structures of Alloecella, someof which have a cowl to protect the animalshead while it moves around.

Family: Conoesucidae

Many of the calocids and helicophids haveorange head capsules like this example fromthe genus Tamasia.

Caddis from the genus Alloecella often have adistinctive cowl at the front of their case.

Distinguishing characteristicsThe head of larval conoesucids is roundwhen viewed from above. The two majorplates on the ventral side of the head arewell separated posteriorly, and the scleritebetween them is rectangular. The antennaeare found very close to the front of the head.Cases are roughly cylindrical, but can beconstructed from a variety of materials. Thecases of several genera are very distinctive,but these designs are not consistent acrossthe whole family. The members of thisfamily vary in size, some of the squat speciescan be around 5 mm long, but most reachabout twice this length.

Possible misidentificationsConoesucid larvae superficially resemblecalocid/helicophid larvae, and to a lesserextent, the antipodoeciids. Mistakes can beavoided by paying close attention to theventral surface of the head. Conoesucidshave the major plates of the ventral surface

well separated by a square sclerite—theventral apotome.

Classification and distributionIn south-eastern Australia there are sixdescribed genera with 21 species. Thisfamily is also found in New Zealand.

Some conoesucid caddis such as thisConoesucus sp. have an impressive hoopbasket case.


Habitat and ecologyConoesucids are common in small- tomedium-sized streams across a variety ofwater speeds, but rarely in very fast water.They can also be found in cold lakes. Theyare thought to feed on a combination ofdecaying plant matter and benthic algae.

Natural historyConoesucid cases are some of the mostattractive structures found in streams.Conoesucus builds a case from bent hoops ofplant matter, giving it a basket-like exterior,while Lingora, Hampa and Matasia all buildcases from rows of sand grains and finegravel. The genus Costora can build either ofthese designs (depending upon the species).It may also construct cases from layers of silk.

Distinguishing characteristicsEcnomids are free-living or caseless caddisthat grow to around 15 mm long. All thoracicsegments are dorsally sclerotised, althoughthe larva may have a gap down the middleof its mesonotum and metanotum (as withthe genus Ecnomina). Many of the speciesfrom the genus Ecnomus have a distinctiveblack and cream head pattern, whileEcnomina’s head is usually orange or brown.Abdominal pro-legs are well developed and

the abdominal segments lack gills.

Possible misidentificationsVery early instars of some hydropsychidsmay lack abdominal gills, and this will makethem key to ecnomids. It is safer to leavevery early instars (<1.5 mm) unidentified.

Classification and distributionTwo genera, Ecnomina and Ecnomus, occurin Australia, with more than 30 species in

Conoesucids are quite a variable-looking group.The stout caddis is Lingora sp. (top), and theslender golden case (bottom) contains Costoradelora. The latter’s case is made entirely of silk.

Caddis larvae from the genus Ecnomus have a detailed head pattern that is often species specific.Ecnomina, the other genus found in Australia has a plain brown or orange head.

Family: Ecnomidae

Caddisflies l 197

The cases of Agapetus (Glossosomatidae) varya lot depending on the gravel or sand that isavailable.

Glossosomatid cases are open at both ends,allowing their occupants to reverse out oftrouble.

temperate Australia. The family Ecnomidaeis found almost worldwide but is missingfrom the colder parts of North America.

Habitat and ecologyEcnomids live in lakes and slow-movingstreams, where they construct simple silk

retreats on rocks and logs. They are rovingpredators and can sometimes be seenhunting or collecting detritus on the surfaceof fine sediment deposits in low flow areas.Young larvae start life as detritivores.

Glossos (Family: Glossosomatidae)

Distinguishing characteristicsThe cases of larval glossosomatids are oftenreferred to as saddle-cases due to theirhumped shape. The ventral side of thesecases is often flatter than the dorsal andconstructed from a finer grain of sand orstone. They are small- to medium-sizedcaddis, most temperate species growing toabout 6 mm. The larvae have partiallysclerotised abdominal pro-legs with adistinctive flat-bottomed ‘U’ shape whenviewed end on. The pronotum narrowstowards the front when viewed from above,and the mesonotum and metanotum eachsport a pair of small sclerites.

Classification and distributionThe family Glossosomatidae occursworldwide and is represented in Australia bya single genus, Agapetus.

Habitat and ecologyGlossosomatids occur in medium- to fast-flowing water that is cool and welloxygenated. They are typically foundamongst large rock substrates, where theyfeed on benthic algae and other fine organicmaterial.

Natural historyThe larval cases of Agapetus can be found inaggregations at the edges of streams oncethe larvae have begun to pupate. Beforepupation, the larvae crawl to near thesurface, cut the base out of their cases, andstick them to stable parts of the stream bed.Larval glossosomatid cases are interestingbecause they are symmetrical, and have twoopenings. The larva can turn around insidethe case, and face in either direction.


Distinguishing characteristicsHelicopsychid larval cases look like smallsnail shells (<6 mm) made from sand grains.They are rarely separated from their cases,so this characteristic will normally besufficient for identification.

Possible misidentificationsLarvae that have been separated from theircases might look a bit like members of theCalocidae/Helicophidae, or Conoesucidae,but they have a curved body, as a result oftheir lives inside their coiled cases.

Classification and distributionHelicopsychids are found worldwide, andrepresented by a single genus, Helicopsyche,

in Australia. Ten species are recorded forsouth-eastern Australia.

Habitat and ecologyHelicopsychids are typically found in coolstreams with moderate- to fast-flowingwaters, although some species may occur inwarmer waters, and sometimes lakes. Theygraze benthic algae from pebbles and largergrades of stone.

Natural historyAll helicopsychid cases have a clockwisespiral when viewed from above. Evenhelicopsychids in the northern hemispherespiral in the same direction—regardless ofthe way water spirals down the kitchen sink!

Distinguishing characteristicsThis is one of the more common families ofcaseless caddis. The front legs of allhydrobiosids are modified in some way,either with pincers, or with elongate claws.The pronotum is always sclerotised and theninth abdominal segment is usually dorsallysclerotised, while the mesonotum and

metanotum are always membranous. Theabdominal pro-legs are distinctly separateand each bears a large sclerite on the outersurface. Hydrobiosids often have brightlycoloured bodies, and come in pink, green,yellow and sometimes blue. They can growto around 15 mm.

Snail-shelled caddis (Family: Helicopsychidae)

Family: Hydrobiosidae

Helicopsyche murrumba is a slow-movingalgae/detritus eater.

The name Helicopsychidae refers to the helical,or round and twisted shape of this caddis’ case.

Caddisflies l 199

Ulmerochorema has an ecnomid-like headpattern, but only its pronotum is sclerotised.

Like all the hydrobiosids, Taschorema hasrobust hooks on its abdominal pro-legs.

Apsilochorema has its forelegs modified into aferocious hook and a muscular femur.

Ethochorema has scissor-like modifications toits forelegs that are effective for holding prey.

Possible misidentificationsHydrobiosids may be confused withphilopotamids, but philopotamids neverhave modified front legs.

Classification and distributionFifteen genera of Hydrobiosidae arerecognised in south-eastern Australia.

Habitat and ecologyHydrobiosids are usually found in cool,clear, fast-flowing streams, and more rarelyin slightly warmer waters. All hydrobiosidsare predatory. They use their modifiedforelegs to capture, disable and rip aparttheir prey.

Natural historyHydrobiosids use very little silk compared to other caddis larvae. They use silk threadsas a safety line while they forage aroundcobbles and then shortly before they pupate,they construct a retreat from sand and smallstones. Once inside, the larva spins a finesilk pupal case that resembles a vitamincapsule. The larva/pupa is clearly visiblethrough the sides of this inner case.

All the hydrobiosids have robust hooks ontheir abdominal pro-legs, and these allowthem to make a quick getaway whenconfronted by opponents or largerpredators.


Distinguishing characteristicsHydropsychid larvae have obviousfilamentous gills on the ventral surface oftheir abdomen, all three thoracic segmentssclerotised, and well-developed abdominalpro-legs with claws. They construct fixedretreats from a variety of materials stucktogether with silk. These retreats tend to be tubes equipped with a net at one end.Larvae rarely exceed 12 mm in length.Some adults have white wings, often withdark patterns on them, and are referred toas snowflake caddis.

Possible misidentificationsSee Ecnomidae.

Classification and distributionThe family Hydropsychidae occursworldwide. Six genera occur in temperateAustralia. They are common in streams insouth-eastern Australia, and can occur inlarge numbers.

Habitat and ecologyHydropsychids are found in moving water,in a wide range of streams, on rocks andlarge woody debris. They are omnivorous,feeding on small animals and plant materialcaught in their nets.

Net spinning caddis (Family: Hydropsychidae)

Adult hydropychids are usually white: this hasearned them the nickname ‘snowflake caddis’.

Net buildersSome of the free-living hydropsychidlarvae use silk to construct nets whichtrap smaller animals and detritus thatare drifting in the current. These netsare sticky and can be held in shape bystruts of vegetation, and gravel. Oftenthe nets are built onto the front of asilken retreat. Net builders usuallyoccur in flowing waters.

Net spinning caddis larvae spend a lot of timein the lean-to attached to the side of their net.

Cheumatopsyche has its abdomen lined withgills so that it can remove enough oxygen fromthe still waters within its silken retreat.

Caddisflies l 201

Distinguishing characteristicsHydroptilids are all very small (<5 mm).Their cases are commonly referred to as‘purse-shaped’, but in some genera they mayresemble wheat seeds. These portable casesare constructed from silk alone, or acombination of silk, algae and sometimesfine sand. The larvae themselves have allthoracic segments sclerotised, and thesesegments are quite thin. In comparison, theabdominal segments are swollen and thefinal segment bears sclerites and hooks. Veryearly instars have sclerites on many of theirabdominal segments and are covered inlong hairs.

Classification and distributionThe Hydroptilidae is a large and very diversefamily with a worldwide distribution. Tengenera are present in temperate Australia.Hydroptilids are very common but can beoverlooked because of their small size.

Habitat and ecologyHydroptilids can be found in a variety ofhabitats. Some species occur amongst waterplants, while others prefer pebbles and

cobbles. Their cases are quite resilient, so itis quite common to find large numbers ofempty cases stuck to surfaces in streams, leftthere by previous generations. Most generaare thought to eat algae (filamentous, orbenthic), but some have been recordedfeeding on the eggs of other invertebrates.Some microcaddis (from the genusOrthotrichia) are parasitic on pupae fromthe caddis families Hydropsychidae andPhilopotamidae.

Microcaddis (Family: Hydroptilidae)

Microcaddis from the genus Hellyethira can bequite common, but their small size makes themdifficult to spot.

Natural historyHydropsychids have been well studied in thenorthern hemisphere. A great deal is knownabout the nets they build and how differentnet structures and sizes are used by differentspecies to capture different types of food.These net structures seem to vary, dependingupon the speed of the water in the river.

Hydropsychid larvae are thought to beterritorial, defending a small area aroundtheir nets from other hydropsychids. Somehydropsychid genera have a series of finegrooves on the underside of their heads,which they rub with their forelegs to makestridulations. These are a series of noises (a bit like those made by cicadas and crickets)

that are thought to warn off other hydro-psychids that might compete for net space.

A Cheumatopsyche net, with a retreat madefrom vegetation and silk to its left.


Distinguishing characteristicsKokiriids vary in size and build a variety ofportable cases. Some are made from sandand small stones and are quite distinctivelyshaped, the dorsal surface projecting overthe front and sides. Other cases are lessdistinctive, being flat and made of detritus.

The larvae have weak sclerotisation on themesonotum and metanotum, and theabdomens have gills and a lateral fringe ofshort, fine hairs. The most distinctivefeature is the fusion of the tibia and tarsi onboth the fore and mid-legs to create two setsof blades to dispatch prey.

Possible misidentificationsYoung philorheithrids (and sometimes evenleptocerids) have pale mid-legs in which thesegmentation is difficult to see. Kokiriids arefairly rare, so dubious identifications arelikely to be from these two groups.

Classification and distributionThe family Kokiriidae is found only inAustralia, New Zealand and South America.Three genera are recorded from south-eastern Australia.

Habitat and ecologyKokiriid larvae occur in sandy-bottomedstreams or small seeps, but they are quiterare even in streams where they havepreviously been recorded. Their fore- andmid-legs are both simplified to form sharppiercing blades, which they use to kill prey.

Family: Kokiriidae

Taskiria otwayensis demonstrates theimpressive blades formed by fused tibia andtarsi in members of the Kokiriidae.

Natural historyHydroptilids are known mainly from theirfinal instars, which construct a case.The earlier instars are very small, highlysclerotised, and covered with long hairs.These hairs are thought to allow them todrift in the water where they feed onplankton and fine organic matter. The laterinstars construct a case and eventuallyattach it to a solid surface shortly beforepupating. The adult caddisflies cansometimes be seen near streams where theyform clouds of animals, mating andpreparing to lay eggs. The adults are alsovery small (4–12 mm) and the numerous

fine hairs on their wings give them a frosty,opaque appearance when in flight.

Most microcaddis, like this Hydroptila feed onalgae.

Caddisflies l 203

Distinguishing characteristicsThe Leptoceridae is one of the commonestfamilies in temperate Australia. Theyconstruct a variety of cases, usually fromwood or finer plant matter, although theymay sometimes incorporate sand and smallstones. The pronotum and mesonotum arestrongly sclerotised, but the metanotum isless so, sometimes without sclerites, but oftenwith two to five sclerites on an otherwisemembranous segment. The metasternumhas two or more hairs, and the antennae areoften long and prominent. The hind legs ofleptocerids are usually long, often twice thelength of the forelegs, and the femur is

divided. The tibia and tarsus of the mid-legsis also divided in some genera. Size is veryvariable for the larvae of this family (2–20 mm). Adult leptocerids have verylong antennae, usually between one–and-a-half to twice the length of the wings.The antennae droop below the animal when it flies.

Possible misidentificationsSome leptocerids (for example Triplectides)have small antennae, and can superficiallyresemble the Calocidae/Helicophidae.These animals can only be properlyseparated using the combination of

Stick caddis (Family: Leptoceridae)

Symphitoneuria opposita is found in slightlysaline waters. Its case is weighted with sand atthe front and always falls opening first.

Notalina spira is a common leptocerid. It has adistinctively striped head and will often movearound by thrashing its body back and forth.

Adult leptocerids have exceptionally longantennae, a character that they share with theless common atriplectidids.

The spotty-headed Oecetis is another commonleptocerid genus. It builds a variety of casesand is found in most habitats.


Triplectides is one of the commonest and most pollution-tolerant genera of the Leptoceridae. It isalso the only genus to hollow out sticks and use them as cases.

chacteristics outlined in the key on page191. Larvae in flat cases (Lectrides sp. andWestriplectes sp.) are often confused withCalamoceratidae. Aquatic caterpillars canbuild a vegetation case but they have simplelegs that are all roughly the same length,rather than long hind legs like a caddis.

Classification and distributionThe Leptoceridae is distributed worldwide,and is extremely diverse. Fifteen genera and more than 70 species occur intemperate Australia. Multiple species arefrequently recorded from fairly smallsections of habitat.

Habitat and ecologyLeptocerids occur in a wide range ofhabitats, from upland streams to temporaryponds and often are the only caddises insaline waters. They are restricted within

these areas to slower-flowing patches, whereorganic matter accumulates. Leptocerids arethought to be omnivorous and the commongenera, Triplectides and Notalina, are oftenfound shredding live and dead plantmaterial. Some, such as the spotty headedOecetis, may be predatory.

Natural historyLeptocerids are possibly the most commoncaddis encountered. Some (Triplectides)construct their cases from sticks and bits ofwood, which they hollow out and line withsilk. This case design is quite cryptic, and itcan make finding these larvae quite difficult.Their size (>10 mm) and their lurchingmovement will eventually give them away.Occasionally leptocerids have been observedwith two larvae housed in opposite ends ofthe same piece of wood.

Caddisflies l 205

Distinguishing characteristicsLimnephilid larvae construct a large, untidycase from either gravel or plant matter.They grow to around 25 mm, haveabdominal gills, and a fringe of hair alongthe sides of their abdominal segments.The prosternum has a ventral horn betweenthe forelegs, which can be difficult to see.The metanotum has two or three pairs ofsmall sclerites. The mesonotum has a singlelarge sclerite and the underside of the firstabdominal segment has more than threepairs of hairs.

Possible misidentificationsPlectrotarsids may appear similar, but theyhave three pairs of sclerites on themesonotum, rather than a single sclerite .

Classification and distributionThe family Limnephilidae occurs worldwideand they are possibly the most diversecaddis in North America, with more than 50 genera. One genus, Archaeophylax, withthree species, is found only in south-easternAustralia.

Habitat and ecologyLimnephilids are found in a variety ofhabitats, ranging from cool mountainstreams, to ponds. Despite their broad rangethey are most abundant in alpine areas.Most limnephilid larvae were thought tofeed on fine organic matter but one species,Archaeophylax canarus, can be anopportunistic carnivore, capable ofdispatching prey around half its size.

Archaeophylax canarus devours a leptocerid.Despite their robust looks limnephilids are likelyto be opportunistic carnivores rather than activehunters.

Family: Limnephilidae

Limnephilids, like this bottled Archaeophylaxochreus, are some of the largest caddis foundin Australia.


Barynema (left) and Marilia bola (right) provide examples of the range of case and body shapeswithin the family Odontoceridae. Barynema is from faster-flowing waters.

Family: Odontoceridae

Distinguishing characteristicsThe Odontoceridae is a difficult group todefine because of the differences betweenthe various species within the family. Theyall have comparatively long anal claws andtheir legs have femurs that are not widerthan other leg segments. The pronotum andmesonotum are heavily sclerotised, while themetanotum has two to four sclerites. Theircases are tubular, slightly curved and madefrom sand and small stones. Fully grownlarvae can be as long as 15 mm.

Possible misidentificationsOdontocerid and philorheithrid larvae arevery similar. Young philorheithrid larvae donot have the tibia and tarsus of their mid-leg fused and are extremely difficult todistinguish from odontocerid larvae.

Classification and distributionTwo genera occur in south-easternAustralia. This is not a commonlyencountered family.

Habitat and ecologyOdontocerids occur in cool clear streams,sometimes in backwaters, where they areprobably shredders or scrapers (as they arein the northern hemisphere), but can beopportunistic scavengers.

Natural historyNorthern hemisphere examples from thisfamily build cases with silk and mud mortarbetween the individual stones, and this isthought to make them more robust andresistant to crushing. These cases are wellsuited to fast-flowing streams, wherecobbles and pebbles often wash loose androll around.

The name Odontoceridae refers to thetooth-like shape of the sand grain cases.In Greek, odontos = tooth, and ceras orkeration = horn.

Marilia fusca is probably an opportunisticpredator. It has been observed actively huntingbut is also known to feed on detritus.

Caddisflies l 207

Distinguishing characteristicsOeconesids have a very circular head whenviewed from above, flat with a prominentridge around the posterior and lateral edges.The antennae are small and close to the eye,and the pronotum has a constriction acrossthe middle, which forms two bulges.The mesonotum and metanotum both havethree pairs of sclerites. The abdominalsegments have gills and a lateral fringe.Cases are made from a variety of plant matter,sometimes including moss. Larvae can bequite large, growing to 14 mm.

Possible misidentificationsOeconesids superficially resembleconoesucids, but conoesucids lack a fringeof hairs along the edges of the abdomen.

Classification and distributionOeconesids occur more commonly in NewZealand but are absent from the rest of theworld. One species, Tascuna, is recordedfrom south-west Tasmania.

Habitat and ecologyOeconesids have been recorded from a smallnumber of fast-flowing streams in well-forested areas. They eat decaying plantmatter.

Distinguishing characteristicsPhilopotamids construct simple, silk-linedretreats on the undersides of rocks. Theyspend some time in these, and some timeroaming free. The head and pronotum aresclerotised, while the mesonotum andmetanotum remain membranous. The mostcharacteristic feature is the membranouslabrum, which is ‘T’ shaped and whiteagainst the orange of the head capsule. Livespecimens have white or cream bodies andorange heads, and grow to around 10 mm.

Possible misidentificationsHydrobiosids and polycentropodids alsohave only the pronotum sclerotised and

Tascuna is a rare and strange-looking caddisfrom south-western Tasmania.

Family: Oeconesidae

Family: Philopotamidae

Philopotamids have a fleshy white labrum,which sits just above the mandibles. This isprobably used while cleaning detritus from their nets.


Family: Philorheithridae

philopotamids with an indistinct labrummay key to hydrobiosids or polycentropodids.Philopotamids never have modified forelegs(like hydrobiosids), or well-developed foretrochanters (like polycentropodids).

Classification and distributionTwo genera of philopotamid, Chimarra andHydrobiosella, with 15 species, occur intemperate Australia.

Habitat and ecologyThe philopotamids are found on and undercoarser sediments in fast-flowing streamsand rivers. They eat algae and other fineorganic particles.

Natural historyPhilopotamids use their ‘T’ shaped labrumto remove fine organic particles from thesack-like nets that they construct on theundersides of rocks. The brush is similar instructure (and possibly function) to thevacuum cleaner accessory that you use toclean curtains and upholstery.

Philopotamidae translates from the Greek asriver lover (philos = lover of, potamos =

river). Many of the first caddis families to benamed were given very general and ratherunimaginative names, as the full diversity ofthe group was unknown at that stage (seePhilorheithridae). After 1750, the naming oftaxa became more interesting as people likethe Swedish naturalist Linnaeus began torelentlessly catalogue things.

Philopotamids often have bright orangesclerotised parts with dark edges.

Distinguishing characteristicsPhilorheithrid cases are made from sand orsmall stones, and are stout and sometimesslightly curved. The larvae are large (8–15 mm), with sclerites on all thoracicsegments. The prosternum has a largesclerite, as does the dorsal surface ofabdominal segment nine. Their mostdistinguishing feature is the fused tibia and tarsus of the mid-leg which functions as a ‘blade’ for killing and grasping prey.Some adult philorheithrids are quitedistinctive in the way that they roll theirwings into a tube.

Tasmanthrus is one of the faster philorheithrids.It moves along using its back two sets of legs,leaving its forelegs free to grab prey.

Caddisflies l 209

Possible misidentificationsOdontocerid and philorheithrid larvae arevery similar. Young philorheithrid larvae donot have the tibia and tarsus of their mid-leg fused and are therefore extremelydifficult to distinguish from smallodontocerid larvae.

Classification and distributionSix philorheithrid genera occur in temperateAustralia (including undescribed ones).

Habitat and ecologyPhilorheithrids occur in cool lakes and fast-flowing streams among pebbles and largerrocks. They are fast-moving predators.

Natural historyThe philorheithrids are fast-moving animalsdespite their heavy cases. They can stalk,and run down prey almost as big as they are.

Common victims include mayfly nymphs,worms, and other caddis larvae. The namePhilorheithridae translates from the Greekas stream lover (philos= lover of, rheithron =a stream channel).

Kosrheithrus demonstrates the formidablesword-like legs that make philorheithrids suchefficient predators. The heavy case helps keepthis caddis from being swept away when all itslegs are stuck in some unfortunate prey.

Adult philorheithrids can be recognised by their posture, and by the way they roll their wings when resting.


Distinguishing characteristicsPlectrotarsids construct untidy cases fromplant matter. Their pronotum has aconstriction that divides it into twoprominent bulges. The prosternum has asmall horn-shaped projection. Themesonotum and metanotum each havethree small sclerites; the ones on themetanotum are greatly reduced. Theseanimals are stout, with short legs (for acaddis) and grow to around 12 mm.

Classification and distributionThree genera are recorded from Australia asadults; the larvae are known for only two ofthese genera. This family is endemic totemperate Australia.

Habitat and ecologyThe plectrotarsids occur in slow-flowingwaters and swamps amongst large amountsof plant matter. They are probablyshredders, though this is assumed fromtheir association with collections of plantmatter in streams.

Natural historyPlectrotarsidae has the somewhat dubioushonour of being the first caddisfly recordedfrom Australia. They are also possibly one ofthe first macroinvertebrates to respond tohuman impacts in Australia. They werefound in 1848 and taken back to Austria foridentification. The original accountsdescribe them as being common in coastalareas south-east of Melbourne, but theyhave now disappeared, along with the ‘chainof ponds’ style of stream in which they usedto live. These days they are rare.

Family: Plectrotarsidae

Family: Polycentropodidae

The rare Plectrotarsus can be recognised by itsmessy case and the constriction on its pronotum.

Distinguishing characteristicsPolycentropodid larvae construct a fixedretreat consisting of a delicate sheet of silkthat covers a depression in a rock or piece of woody debris. Larvae have a sclerotisedpronotum but their mesonotum andmetanotum are membranous. The foretrochanters of these animals are welldeveloped and form a blade-like projectionabove the forelegs. The abdominal pro-legsare well developed and armed with claws.These larvae rarely exceed 15 mm.

Plectrocnemia, a polycentropodid, lookssuperficially like a philopotamid, but has aspotty head and a sclerotised labrum

Caddisflies l 211

Possible misidentificationsPolycentropodids superficially resembleboth the philopotamids and hydrobiosids,however their forelegs are never modifiedlike hydrobiosids, and they lack theT-shaped labrum of philopotamids.

Classification and distributionEight genera of Polycentropodidae arefound in temperate Australia. The familyoccurs worldwide.

Habitat and ecologyPolycentropodids occur in slow-flowingstreams, on rocks and woody debris. Theirfeeding habits vary greatly: they have beenrecorded as filter feeders, shredders andpredators. The commoner genera appear tobe predatory. They spend much of theirtime skulking in a retreat, which isconnected to a fine network of silk strands.

When prey blunder into these strands, thelarva springs from hiding and eats them.The whole set-up is a bit like a messy,underwater spider web.

Distinguishing characteristicsThe tasimiids are medium-sized caddislarvae (5–8 mm) that construct cases fromsand or small stones. The dorsal surfaceoverhangs the opening of the case, and thewhole structure is slightly dorso-ventrallyflattened. The larvae have a rounded headwith bulging eyes. The pronotum andmesonotum are both sclerotised, while themetanotum has two pairs of small roundsclerites. The first abdominal segment has apair of lateral humps that are covered withmicroscopic hooks. The abdomen has afringe of hairs and lots of gills.

Possible misidentificationsThese animals can superficially resembleglossosomatids (from their cases), buttasimiids have the mesonotum fullysclerotised and their cases taper at one end,while the glossosomatids have symmetricalcases.

Paranyctiophylax guards its retreat and thesurrounding tripwires vigilantly. Its nametranslates roughly as ‘almost a night watchman’.

Tasimia has two prominent lateral humpshidden within its chunky case. These possiblyhelp the animal scale steep rocks, or creepforward in fast flows.

Family: Tasimiidae


Several generations of empty tasimiid cases cluster along the shoreline of a small stream. Thisprime pupal real estate allows the newly emerging caddis adults to step out onto land withoutgetting their feet wet.

Classification and distributionTwo genera, Tasimia and Tasiagma, with sixspecies are known from south-easternAustralia and the family is found only inAustralia and South America. They canoccur in large numbers in fairly localisedpatches. This family is restricted to south-eastern Australia.

Habitat and ecologyThese animals are usually found in cold,swift streams. Tasimiid larvae graze onbenthic algae, and fine organic particles.(They can sometimes be seen cleaning thealgae from their stone cases.)

Natural historyThe lateral humps on the first abdominalsegment of tasimiids can be used to assistthe legs of the animal when it is movingthrough fast-flowing water. The animalpulls itself partially out of its case, and uses

the rings of hooks to stick to rocks. Black flylarvae (Diptera) employ a similar structureand coat the rock with silk before attachingthemselves to it with a ring of hooks. It isprobable that tasimiids are employing asimilar method. Tasimiids crawl up the sidesof the stream bank before pupating and fixtheir cases just under the surface of thewater. Huge collections of these cases canaccumulate over time, with several yearsworth of pupal cases layered on top of oneanother.

SIGNAL grades l 213

Higher taxa

Acarina . . . . . . . . . . . . . . . . . . . 6

Amphipoda . . . . . . . . . . . . . . . 3

Anaspidacea . . . . . . . . . . . . . . 6

Anostraca . . . . . . . . . . . . . . . . . 1

Bivalvia . . . . . . . . . . . . . . . . . . . 3

Branchiura . . . . . . . . . . . . . . . 1

Bryozoa . . . . . . . . . . . . . . . . . . . 4

Coleoptera . . . . . . . . . . . . . . . . 5

Collembola . . . . . . . . . . . . . . . 1

Conchostraca . . . . . . . . . . . . . 1

Decapoda . . . . . . . . . . . . . . . . . 4

Diplopoda . . . . . . . . . . . . . . . . 4

Diptera . . . . . . . . . . . . . . . . . . . . 3

Ephemeroptera . . . . . . . . . . 9

Gastropoda . . . . . . . . . . . . . . . 1

Hemiptera . . . . . . . . . . . . . . . . 2

Hirudinea . . . . . . . . . . . . . . . . 1

Hydrozoa . . . . . . . . . . . . . . . . . 1

Isopoda . . . . . . . . . . . . . . . . . . . 2

Lepidoptera . . . . . . . . . . . . . . 2

Mecoptera . . . . . . . . . . . . . . . 10

Megaloptera . . . . . . . . . . . . . . 8

Nematoda . . . . . . . . . . . . . . . . 3

Nemertea . . . . . . . . . . . . . . . . . 3

Neuroptera . . . . . . . . . . . . . . . 6

Nematomorpha . . . . . . . . . . 6

Notostraca . . . . . . . . . . . . . . . . 1

Odonata . . . . . . . . . . . . . . . . . . 3

Oligochaeta . . . . . . . . . . . . . . 2

Plecoptera . . . . . . . . . . . . . . . 10

Porifera . . . . . . . . . . . . . . . . . . . 4

Trichoptera . . . . . . . . . . . . . . . 8

Turbellaria . . . . . . . . . . . . . . . . 2

Families

Aeshnidae . . . . . . . . . . . . . . . . 4

Ameletopsidae . . . . . . . . . . . 7

Amphisopidae . . . . . . . . . . . 1

Ancylidae . . . . . . . . . . . . . . . . . 4

Antipodoeciidae . . . . . . . . . 8

Aphroteniinae . . . . . . . . . . . . 8

Athericidae . . . . . . . . . . . . . . . 8

Atriplectididae . . . . . . . . . . . 7

Atyidae . . . . . . . . . . . . . . . . . . . . 3

Austrocorduliidae . . . . . . 10

Austroperlidae . . . . . . . . . . 10

Baetidae . . . . . . . . . . . . . . . . . . 5

Belostomatidae . . . . . . . . . . . 1

Bithyniidae . . . . . . . . . . . . . . . 3

Blephariceridae . . . . . . . . . 10

Branchipodidae . . . . . . . . . . 1

Caenidae . . . . . . . . . . . . . . . . . . 4

Calamoceratidae . . . . . . . . . 7

Calocidae . . . . . . . . . . . . . . . . . 9

Ceinidae . . . . . . . . . . . . . . . . . . 2

Ceratopogonidae . . . . . . . . . 4

Chaoboridae . . . . . . . . . . . . . 2

Chironominae . . . . . . . . . . . . 3

Cirolanidae . . . . . . . . . . . . . . . 2

Clavidae . . . . . . . . . . . . . . . . . . 3

Coenagrionidae . . . . . . . . . . 2

Coloburiscidae . . . . . . . . . . . 8

Conoesucidae . . . . . . . . . . . . 7

Corbiculidae . . . . . . . . . . . . . 4

Corduliidae . . . . . . . . . . . . . . 5

Corixidae . . . . . . . . . . . . . . . . . 2

Corophiidae . . . . . . . . . . . . . . 4

Corydalidae . . . . . . . . . . . . . . 7

Culicidae . . . . . . . . . . . . . . . . . 1

Curculionidae . . . . . . . . . . . . 2

Diamesinae . . . . . . . . . . . . . . . 6

Diphlebiidae . . . . . . . . . . . . . . 6

Dixidae . . . . . . . . . . . . . . . . . . . 7

Dolichopodidae . . . . . . . . . . 3

Dugesiidae . . . . . . . . . . . . . . . 2

Dytiscidae . . . . . . . . . . . . . . . . 2

Ecnomidae . . . . . . . . . . . . . . . 4

Elmidae . . . . . . . . . . . . . . . . . . . 7

Empididae . . . . . . . . . . . . . . . . 5

Ephydridae . . . . . . . . . . . . . . . 2

Erpobdellidae . . . . . . . . . . . . 1

Eusiridae . . . . . . . . . . . . . . . . . 7

Eustheniidae . . . . . . . . . . . . 10

Gelastocoridae . . . . . . . . . . . 5

Gerridae . . . . . . . . . . . . . . . . . . 4

Glacidorbidae . . . . . . . . . . . . 5

Glossiphoniidae . . . . . . . . . . 1

Glossosomatidae . . . . . . . . . 9

Gomphidae . . . . . . . . . . . . . . . 5

Gordiida . . . . . . . . . . . . . . . . . . 5

Gripopterygidae . . . . . . . . . 8

Gyrinidae . . . . . . . . . . . . . . . . . 4

Haliplidae . . . . . . . . . . . . . . . . 2

Hebridae . . . . . . . . . . . . . . . . . . 3

Helicophidae . . . . . . . . . . . . 10

Helicopsychidae . . . . . . . . . . 8

Hemicorduliidae . . . . . . . . . 5

Hydraenidae . . . . . . . . . . . . . . 3

Hydridae . . . . . . . . . . . . . . . . . . 2

Hydrobiidae . . . . . . . . . . . . . . 4

Hydrobiosidae . . . . . . . . . . . . 8

Listing of SIGNAL grades


Hydrochidae . . . . . . . . . . . . . . 4

Hydrometridae . . . . . . . . . . . 3

Hydrophilidae . . . . . . . . . . . . 2

Hydropsychidae . . . . . . . . . . 6

Hydroptilidae . . . . . . . . . . . . 4

Hygrobiidae . . . . . . . . . . . . . . 1

Hymenosomatidae . . . . . . 3

Hyriidae . . . . . . . . . . . . . . . . . . 5

Isostictidae . . . . . . . . . . . . . . . 3

Janiridae . . . . . . . . . . . . . . . . . . 3

Kokiriidae . . . . . . . . . . . . . . . . 3

Koonungidae . . . . . . . . . . . . . 1

Leptoceridae . . . . . . . . . . . . . 6

Leptophlebiidae . . . . . . . . . . 8

Lestidae . . . . . . . . . . . . . . . . . . . 1

Libellulidae . . . . . . . . . . . . . . . 4

Limnephilidae . . . . . . . . . . . . 8

Lindeniidae . . . . . . . . . . . . . . . 3

Lymnaeidae . . . . . . . . . . . . . . 1

Macromiidae . . . . . . . . . . . . . 8

Megapodagrionidae . . . . . 5

Mesoveliidae . . . . . . . . . . . . . 2

Muscidae . . . . . . . . . . . . . . . . . 1

Nannochoristidae . . . . . . . . 9

Naucoridae . . . . . . . . . . . . . . . 2

Neoniphargidae . . . . . . . . . . 4

Nepidae . . . . . . . . . . . . . . . . . . . 3

Neurorthidae . . . . . . . . . . . . . 9

Noteridae . . . . . . . . . . . . . . . . . 4

Notonectidae . . . . . . . . . . . . . 1

Notonemouridae . . . . . . . . . 6

Odontoceridae . . . . . . . . . . . 7

Oeconesidae . . . . . . . . . . . . . . 8

Oniscidae . . . . . . . . . . . . . . . . . 2

Oniscigastridae . . . . . . . . . . . 8

Ornithobdellidae . . . . . . . . . 1

Orthocladiinae . . . . . . . . . . . 4

Osmylidae . . . . . . . . . . . . . . . . 7

Palaemonidae . . . . . . . . . . . . 4

Paracalliopidae . . . . . . . . . . . 3

Paramelitidae . . . . . . . . . . . . 4

Parastacidae . . . . . . . . . . . . . . 4

Philopotamidae . . . . . . . . . . 8

Philorheithridae . . . . . . . . . 8

Phreatoicidae . . . . . . . . . . . . . 4

Physidae . . . . . . . . . . . . . . . . . . 1

Planorbidae . . . . . . . . . . . . . . 2

Pleidae . . . . . . . . . . . . . . . . . . . . 2

Podonominae . . . . . . . . . . . . 6

Polycentropodidae . . . . . . . 7

Pomatiopsidae . . . . . . . . . . . 1

Protoneuridae . . . . . . . . . . . . 4

Psephenidae . . . . . . . . . . . . . . 6

Psychodidae . . . . . . . . . . . . . . 3

Ptilodactylidae . . . . . . . . . . 10

Pyralidae . . . . . . . . . . . . . . . . . . 3

Richardsonianidae . . . . . . . 4

Sciomyzidae . . . . . . . . . . . . . . 2

Scirtidae . . . . . . . . . . . . . . . . . . 6

Sialidae . . . . . . . . . . . . . . . . . . . 5

Simuliidae . . . . . . . . . . . . . . . . 5

Siphlonuridae . . . . . . . . . . . 10

Sisyridae . . . . . . . . . . . . . . . . . . 3

Sphaeriidae . . . . . . . . . . . . . . . 5

Sphaeromatidae . . . . . . . . . . 1

Spongillidae . . . . . . . . . . . . . . 3

Stratiomyidae . . . . . . . . . . . . 2

Synlestidae . . . . . . . . . . . . . . . . 7

Syrphidae . . . . . . . . . . . . . . . . . 2

Tabanidae . . . . . . . . . . . . . . . . . 3

Talitridae . . . . . . . . . . . . . . . . . 3

Tanyderidae . . . . . . . . . . . . . . 6

Tanypodinae . . . . . . . . . . . . . 4

Tasimiidae . . . . . . . . . . . . . . . . 8

Telephlebiidae . . . . . . . . . . . . 9

Temnocephala . . . . . . . . . . . . 5

Thaumaleidae . . . . . . . . . . . . 7

Thiaridae . . . . . . . . . . . . . . . . . 4

Tipulidae . . . . . . . . . . . . . . . . . 5

Urothemistidae . . . . . . . . . . . 1

Veliidae . . . . . . . . . . . . . . . . . . . 3

Viviparidae . . . . . . . . . . . . . . . 4

Family groupsAeshnid-like dragonflies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Corduliid/libellulid dragonflies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Dolichopodidae, Tabanidae and Tipulidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Ephydridae, Muscidae, Sciomyzidae and Syrphidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Primitive dragonflies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Note: Scores modified from SIGNAL and SIGNAL 2, Bruce Chessman (1995, 2001)

Glossary l 215

abdomen – posterior part of the body, behind thethorax (see p. 17)

adductor muscle – a muscle that pulls thingstogether (see p. 46)

aestivate – to become dormant over summer,especially during dry periods

algae – simple, aquatic, plant-like organisms thatcan use sunlight and nutrients to producetheir own energy

antenna (plural: antennae) – paired, longappendages attached to the head (see p. 17)

anterior – the front (see p. 17)

apex – the tip or end of something

apical – at the tip of a limb (from apex)

appendage – a part of an animal, like a leg or anantennae, that is attached to its main trunkbut clearly separate

aquatic – found in water

arthropods – invertebrates with an externalskeleton from the phylum Arthropoda (forexample insects and crustaceans)

asexual reproduction – reproduction that doesnot need both males and females

atmospheric oxygen – oxygen that is part ofgaseous air (the stuff we breath)

benthic – from the bed of a river or lake

benthic algae – algae that grows on the stream orlake bed

benthos – animals or plants that live in or on thestream or lake bed

bioassessment – assessing a river’s health usingthe animals and plants that live in it

biomass – a measure of a quantity or mass oforganisms

budding – asexual reproduction by dividing andforming multiple individuals from a singleparent

carapace – hard cover over thorax, or more of thebody in crustaceans

carina – a ridge

carnivore – an animal that eats other animals

catchment – the land from which water flowsinto a river

caudal filaments – tails, usually paired (see cerci)

cephalothorax – a body segment equivalent to afused head and thorax

cerci – the outer two tails, particularly onmayflies and stoneflies (see p. 131)

chelae – pincer-like claws

chelate – bearing pincer-like claws

chitin – the main material that insects’ externalskeletons are made of

cilia (plural: ciliae) – microscopic hairs thatoccur in large quantities and are used tomove small animals or their food

claspers – a pair of limbs used by a male to graspthe female, usually at the end of the abdomen

class – a taxonomic level (see p. 18)

classification – a system that separates plants andanimals into groups such as: Class, Order,Family, Species, etc.

collectors – animals that feed on detritus thatthey collect either from water (filter feeders)or the surfaces around them

community – the different species that live in thesame area and use the same resources

compound eye – an eye made from lots ofsmaller ‘eyes’

convoluted – with a complicated, folded edge

coxa – a leg segment closest to the body

crochet – a circlet or arc of small hooks

described species – species that can be recognisedfrom formal, scientifically publisheddescriptions

detritivore – an animal that eats detritus

detritus – decomposing animal and plant matter,such as old leaves

Glossary


dextral – coiled (particularly snails) so that theopening of the shell is on the right whenviewed ventrally (see p. 46)

diatoms – small, single celled algae in glass-likecases

digitate – finger-like

dissolved oxygen – oxygen that is part of liquidwater

distal – distant from the main body (for examplethe far end of an antenna, opposite toproximal)

dorsal – on or of the back or top (see p. 17)

dorso-ventrally flattened – flattened so that theback (dors) and front (venter) are closer,opposite to flattened from the sides

ecology – the study of the way animals and plantsinteract with each other and their physicalsurroundings

elytron (plural: elytra) – hardened front wingsthat cover and protect the hind wings (see p. 92)

emerge – to leave the water (usually as an adultinsect after living within the stream as a larvaor nymph)

endangered – in danger of becoming extinct

endemic – distribution restricted to a singlegeographic location

ephemeral – short lived

epi- – of the edge

epiphytic – growing on the surface of otherplants

exopod – extra outer limb especially in primitivecrustaceans

exoskeleton – an external skeleton or hardenedskin

extant – still living, the opposite of extinct

extinct – no longer living (of a species)

family – a taxonomic level (see p. 18)

fauna – animals

femur (plural: femora) – a leg segment (see p. 161)

filamentous algae – algae that grow in long thinstrings

filter feeders – animals that filter water for foodparticles

flagellum (plural: flagellae) – a whip-like process

flora – plants

fore trochantin – (see diagram on p. 191)

frontoclypeus – an hourglass-shaped headsclerite (see p. 191)

gemmule – see sponges p. 33

genus (plural: genera) – a taxonomic level (see p. 18)

gill – a plate-like or filamentous organ with alarge surface area, used to extract oxygenfrom the water

gnathopods – the first two legs on amphipods,often with robust, chelate claws (see p. 68)

grazers – animals that feed on dense patches ofplant, such as grass or periphyton

habitat – the physical space (and sometimes thechemical requirements) required by anorganism to live

halteres – small, knob-shaped structures thatreplace wings on the metathorax of true flies(see p. 112)

head capsule – a hardened capsule that covers thehead (see p. 112)

helicoid – spiralling, said about snail shells

herbivore – an animal that feeds on plants

hydrophilic – water loving

hydrophobic – water repellent

instar – stages of growth in animals that shedtheir external skeletons, each time the animalsheds it starts a new instar

invertebrate – an animal without a backbone orthe small bones (vertebrae) from which it isbuilt

kingdom – a taxonomic level (see p. 18)

labial palp – paired, hinged plates that form partof the dragonfly mouthparts (see p. 161)

labium – the mouthparts equivalent to a lower lip(see p. 191)

labrum – the mouthparts equivalent to an upperlip (see p. 191)

larva (plural: larvae) – a juvenile insect

Glossary l 217

lateral – on or of the sides (see p. 17)

laterally flattened – flattened from the sides

lentic – of still water such as ponds and lakes

littoral zone – a zone along the edge of a waterbody, often defined by high water marks

longitudinal – along the length of an object

lotic – of running/flowing water such as riversand streams

macroinvertebrate – an invertebrate which islarge enough to see without a microscope

macrophyte – a non-algal water plant

mandible – one of the more hardenedmouthparts, often used for biting, orchewing

mantle – of gastropods, the layer of flesh closestto the shell (see p. 46)

marginal – near the edge of the water

marsupium – consists of appendages that covereggs in some crustaceans

maxillary palps – one of the sets of mouthparts(paired) in many arthropods (see p. 92)

mentum – roughly equivalent to a chin, also atooth plate in chironomids (see p. 112)

meso- – middle (see p. 17)

meta- – last (see p. 17)

monitoring – sampling repeatedly, to pick upchanges that might occur over time

moult – to lose the outer layer of skin (verb), orthe outer layer of skin that is lost (noun)

nektonic – a description of animals that swimfreely in open water

notum (plural: nota) – dorsal part of a thoracicsegment

nymph – a juvenile insect that closely resemblesthe adult, but has poorly developed wings

ocelli – simple eyes like those on larvae

omnivore – an animal that eats both plant andanimal matter

operculum – a small round door used bygastropods to close their shells

order – a taxonomic level (see p. 18)

organism – a living thing (includes plants,animals, fungi, bacteria etc.)

palp – a small finger-like appendage, fleshy inmolluscs and jointed in arthropods

peduncle – the base segment that rami areattached to in crustaceans (see p. 68)

pelagic – living in the middle or top of a waterbody rather than on its bed

periphyton – a layer of slime on rocks and othersurfaces in the stream which is made up ofalgae, fungi and bacteria

phylum – a taxonomic level (see p. 18)

phytoplankton – microscopic plants that floatfree in water

pigmented – darkened or coloured

plankton – microscopic plants and animals thatfloat free in water

plastron – a breathing organ consisting of a thinlayer of hairs that trap air

pleon – the part of a crustacean body that thepleopods are attached to (see p. 68)

pleopods – the appendages on a crustaceanbehind the legs, usually for swimming (see p.68)

pleotelson – the segment formed by the fusion ofthe pleon, and telson in phreatoicid isopods

post- – after

posterior – the hind end (see p. 17)

postmentum – especially in odonates, one of themouthparts (see p. 161)

preapical – near, but not at the tip of a limb

predators – animals that hunt, kill and eat otheranimals

prehensile – adapted for grasping, like fingers

prementum – especially in odonates, one of themouthparts (see p. 161)

pre- – before

pro- – first (see p. 17)

proboscis – the beak-like mouthparts of a truebug (Hemiptera, see p. 144)

processes – bits that stick out but aren’tconsidered as separate limbs

pro-legs – simple, fleshy legs without proper joints


proximal – near the body (opposite of distal)

pubescent – hairy

pupa – the phase between larva and adult, usuallynon-moving and in a protective case

radula – a hard, file-like structure in molluscs(see pp. 46 and 49)

ramus (plural: rami) – the final segments of theuropod, usually paired on amphipods (see p. 68)

raptorial – designed for grasping, usually withlarge claws

rare – an animal with a small geographicdistribution

reach – a section of river

riffle – a fast-moving, shallow section of riverwhere the water surface is disturbed by theriver bed

river health – a concept used to help explain theidea of river degradation

rostrum – see proboscis

sclerite – a hardened plate of external skeleton

sclerotised – hardened, leathery, often darkorange, brown or black

scraper – an animal that scrapes food from hardsurfaces

scutellum – a small triangular plate bordered bythe wings and the pronotum in beetles andbugs (see p. 92)

sessile – attached to a solid surface

seta (plural: setae) – stiff hairs

shredder – an animal that gets its food by pullingapart organic matter such as leaves

sinistral – coiled (particularly snails) so that theopening of the shell is on the left whenviewed ventrally (see p. 46)

siphon – a hollow tube used by some true bugs topuncture the water surface while breathing

snags – fallen branches and logs that providehabitat within a river or pond

sp. – species (singular); usually indicates that theanimal is unknown beyond genus level

species – a taxonomic level (see p. 18)

spiracle – a hole that connects the insides of aninsect to a supply of air (see p. 112)

spp. – species (plural) indicates many specieswithin a genus

sternum – ventral part of a body segment

swimming hairs – a fringe of hairs, (usually alonga leg) that allow it to work like a paddle

tarsus (plural: tarsi) – the final segments of a legafter the tibia (see p. 161)

telson – the central piece of a crustacean tail fan,shield-shaped (see p. 68)

tergite – a sclerotised dorsal plate

terminal filament – the central tail (of three inmayflies)

terrestrial – found on land

thoracic – of the thorax

thorax – the body segments immediately after thehead (see p. 17)

tibia – a leg segment (see p. 161)

trachea – microscopic tubes thoughout aninsect’s body that carry air to every cell

trophic levels – a more scientific name for theecological ‘jobs’ described on page 7

tubercles – rounded lumps

uniramous – with a single ramus (see ramus)

uropod – the last three appendages on theunderside of a crustacean (see p. 68)

ventral – on or of the underside (see p. 17)

ventral apotome – a small square sclerite on theunderside of a caddis larva’s head (see p. 191)

vulnerable – likely to become endangered undercurrent conditions

water column – a term used to convey the idea ofanimals and plants moving vertically throughthe water

wing pads/buds – the covers on a nymph’s backthat house its developing wings

zooplankton – microscopic animals that floatfree in water

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Index l 227

abdomen 17abdominal pro-legs 187Acarina 59Acruroperla 183Acruroperla atra 183Actinodactylella 38adductor muscles 46Aeshna brevistyla 174Aeshnidae 18, 19, 163, 164, 174Agapetus 197Alathyria 50albumen /shell gland 46alder fly larvae 89algae 7, 32, 38, 44, 51, 55, 64, 65,

81, 87, 101, 103, 104, 105, 118,121, 122, 123, 126, 128, 138,141, 143, 165, 175, 180, 194,196, 197, 198, 201, 208, 212

Allanaspides 74Alloecella 195Amarinus lacustris 81, 82Ameletoides lacusalbinae 143Ameletopsidae 19, 136Amphipoda 16, 68, 69–71Amphipterygidae 168Anacaena 106Anaspidacea 73, 74Anaspides 73, 74

tasmaniae 73, 74Anaspididae 73, 74Ancylastrum 51, 56Ancylidae 47, 51, 52Anisocentropus 193Anisops 157, 158Anisoptera 164Annelida 44Anophelinae 122Anostraca 68, 75, 76antennae 17Antipodeus 70Antipodoecia 192Antipodoeciidae 188, 192Antipodophlebia 174Antipodrilus 44Aphelocheiridae 146Aphroteniinae 120, 121Apistomyia 118Apochauliodes 89Apsilochorema 199Aquarius 152

aquatic caterpillars 86, 204aquatic plants 2, 3, 7, 32, 37, 87,

97, 99, 107, 111, 138, 141,146, 165, 185, 189

aquatic weevils 97Archaeophylax 205

canarus 205ochreus 205

Archicauliodes 89diversus 89

Archipetalia auriculata 179Archipetaliidae 164, 179Artemia salina 75Arthropoda 9, 18Asellota 72asexual reproduction 33Astacopsis 78

gouldi 82Atalomicria 141Atalophlebia 132, 133, 134, 141

albiterminata 133, 134, 141australis 141

Athericidae 13, 116, 117Atriplectides 192, 193

dubius 192Atriplectididae 188, 192, 193Atyidae 77–81Aulonogyrus 103Aulorilus 44Australomedusa 34, 35Austroaeschna 162, 164

unicornis 164Austroargiolestes 171

icteromelas 171Austrocerca 186Austrocercella 186Austrochiltonia 69Austrocorduliidae 164, 175Austrocuripira 118Austrogammarus 70Austrogomphus 177

guerini 177Austroheptura 183Austrolestes 170

analis 170cingulatus 170psyche 162

Austrolimnius 100Austronepa 155Austropentura 183

Austropeplea 55tomentosa 54, 55

Austroperlidae 181, 183Austropetalia 179Austropetaliidae 164, 179Austrophlebioides 132, 141Austrosialis ignicollis 89Austrosimulium 129Austrothaumalea 130Austrovelia 160

backswimmers 144, 146, 157, 158bacteria 7, 8, 36, 64, 65, 80, 121Baetidae 134, 137, 138Bagous hydrillae 97Barynema 206Bathynellacea 73, 74Bayardella 56beetles 2, 5, 12, 16, 38, 92–111Beddomeia 53Bellamya heudei guangdungensis

52Belostomatidae 145, 146, 148, 149Benthodorbis 53Berosus 106, 107billabongs 2birds 7, 42, 61, 64Bithynia 52Bithyniidae 52biting midges 13, 116, 119Bivalvia 46, 47–51black flies 13, 113, 116, 129black fly larvae 9black spinners 141blackworm 44bleffs 118Blephariceridae 118body parts 17Boeckella major 65Branchinella 75Branchiura sowerbyi 44, 45brine shrimp 75bug-picking 4Bungona 137

caddis flies 2, 9, 14, 16, 162,187–212

Caenidae 132, 134, 138, 139Caenota plicata 194Calamoceratidae 188, 193, 204

Index


Calanoida 65Calocidae 188, 194Carabidae 96carbon 9, 156Cardioperla 185Caridina 80caterpillars, aquatic 86, 87Ceinidae 69, 70, 71Centroptilum 137Ceratopogonidae 13, 119Ceratopogoninae 119cerci 131Cercotmetus 155Chaetogaster limnaei 44Chaoboridae 123Chaoborus edulis 13Chathamiidae 188Cherax 78, 83

destructor 82Cheumatopsyche 200Chimarra 208Chironomidae 112, 113, 115,

116, 120Chironominae 15, 120, 121Chironomus 120, 121Chrysomelidae 96Chydoridae 64cilia 33, 40, 49ciliated groove 46, 49Cirolanidae 72, 73Cladocera 34, 63, 64clam shrimp 66clams 47Clark 16Class 17classification 18Cloeon 137Clytocosmus 113, 115Cnephia 129Cnidaria 9, 34, 35Coenagrionidae 164, 167Coleoptera 92–111collectors 9Collembola 84, 85Coloburiscidae 139, 140Coloburiscoides 15, 139Colubotelson 73Conchostraca 66, 67Conoesucidae 188, 195, 196Conoesucus 195, 196Copepoda 64, 65Corbicula 49, 50Corbiculidae 49, 50Cordulephyidae 164, 175Corduliidae 162, 163, 176Cordylophora 34, 35

Corisella 13edulis 13mercenaria 13

Corixidae 146, 149Corophiidae 70, 71Corophium 70Corydalidae 89Cosmioperla 184Costora 196couplet 20coutas 163coxal plates 94Coxelmis 100Coxiella 57crabs 77, 78, 79, 81, 82crane flies 113, 124Craspedacusta 34, 35

sowerbyi 35Craspedella 38crawling water beetles 103crayfish 4, 36, 38, 70, 71, 72, 74,

77, 78, 79, 82, 83crayfish symbionts 36, 38creeping water bugs 154crustaceans 3, 13, 16, 68, 79, 83Crypturoperla 181, 183Cucumerunio 50Culicidae 13, 113, 115, 122Culicinae 122Cura 39Curculionidae 97Cyclopoida 65Cymatia 150Cyphon 111Cyzicus 66

daddy long-legs 124damselflies 18, 161–173dance flies 116Dasyheleinae 119Dasyomma 117Decapoda 77–83Dero 44detritivores 7, 9Diamesinae 120, 121Diaprepocoris 150Dineutus 103Diphlebiidae 163, 164, 168Diplonychus eques 148Dipseudopsidae 189Dipsocoridae 146Diptera 13, 112–130 134, 212diving beetles 92, 96, 98, 108Dixella 123Dixidae 123dobsonfly larvae 89

dobsonfly 7Dolichopodidae 124dollies 124Dolomedes 60, 61dragonflies 2, 7, 16, 18, 134, 161,

162, 163, 164, 165, 173–179,180

drought tolerant 3Dugesia 39Dundundra 185duns 132, 133, 141Dytiscidae 13, 92, 93, 96, 98, 99

earthworms 44Ecnomidae 188, 196, 197Ecnomina 196Ecnomus 196ecology, freshwater 12Edmundsiops 137Edwardsina 118eggs 3, 9, 12, 13, 14, 40, 43, 45,

47, 52, 54, 55, 60, 63, 64, 65,66, 67, 71, 75, 76, 79, 97, 99,103, 105, 107, 109, 116, 117,132, 134, 146, 148, 150, 170,

180, 201, 202Elmidae 96, 100, 101Elminae 100elytra 92emergence 12Empididae 116, 117Enchytraeidae 44Engaeus 83Enithares 157Enochrus 96, 106Ephemeroptera 17, 131–143ephippium 64Ephydridae 13, 117, 126, 127Epiproctophora 164, 174–179Episynlestes 173equipment 3Erpobdellidae 41, 42estuaries 3Ethochorema 199Euastacus 78

armatus 83bispinosus 78

Eunotoperla 185Eusiridae 69, 70, 71Eusthenia 184Eustheniidae 180, 181, 184Eusynthemis 176Eutanyderus 130Eylaidae 59

fairy shrimp 75

Index l 229

false spider crabs 77Family 18Fasciola hepatica 55femur 144, 161Ferrissia 51, 52

petterdi 51, 52tasmanica 51, 52

filter feeders 9fish 4, 7, 14, 44, 50, 60, 72, 75,

82, 99, 132, 143, 148, 150,156, 158, 163, 182, 184

fisher/fishing spiders 60, 61fishing 14, 78, 132, 134, 163Flabellifera 72flatworms 9, 13, 14, 36, 39, 40flies 112–130

artificial/fishing 14–15flight 134foodweb 5–9

diagram 6Forcipomyiinae 119fore trochantin 187frogs 7, 42frontoclypeus 187fungi 8, 36, 85furcula 84

Gabbia see BithyniaGalaxias 143Gastropoda 9, 46, 47, 48, 49,

51–58Gelastocoridae 151gemmules 33Genus 18Geocharax 83Gerridae 145, 146, 152, 153, 159Gerrinae 152giant water bugs 145, 148gilgie 78gills 131Glacidorbidae 47, 53Glacidorbis 53Glossiphoniidae 42glossos 197Glossosomatidae 188, 197Glyptophysa 47, 56–57

gibbosa 57gnathopods 68, 71Goddard 16Gomphidae 164, 176, 177Gomphomacromiidae 164, 175Goondnomdanepa 155gordian worms 36, 37, 38Gordiida 37Gramastacus 83Graphelmis 100Grapsidae 79

Greek 7, 17, 35, 37, 44, 47, 59, 74,82, 84, 113, 161, 192, 207,

208, 209Gripopterygidae 181, 185Griseargiolestes 171Gyraulus 56

tasmanicus 56Gyrinidae 102, 103Gyrinus 103

habitatsestuaries 3puddles, dams, billabongs,

ponds and lakes 2springs, streams and rivers 1wetlands, swamps and

marshes 3Haliplidae 103Haliplus 103Halobates 152Haloniscus 72halteres 112Hampa 196Haplotaxidae 44Harpacticoida 65Harrisius 120head capsule 112Hebridae 159, 160Hebrus 160Helicophidae 188, 194Helicopsyche 198

murrumba 198Helicopsychidae 188, 198Helicorbis 56Hellyethira 201Helochares 92, 106, 107Hemicordulia 164, 176

tau 162, 163, 164, 175, 176Hemicorduliidae 164, 175Hemiphlebia mirabilis 168Hemiphlebiidae 164, 168Hemiptera 113, 144–160herbivores 7hermaphrodite 9Heterias 72Heteroptera 144, 146Hirudinea 9, 41Hirudinidae 41, 42Hirudo medicinalis 41horse flies 13, 113, 124horsehair worms 36, 37hover flies 113, 127Hydora 101Hydra 9, 34, 35Hydrachnidae 60Hydraena 104, 105Hydraenidae 93, 104, 105

Hydrobiidae 49, 53, 54Hydrobiosella 208Hydrobiosidae 188, 198, 199Hydrochidae 106, 107Hydrochus 107Hydrometra strigosa 153Hydrometridae 153Hydrophilidae 93, 99, 106, 107,

108Hydropsychidae 188, 189, 191,

196, 200, 201Hydroptila 202Hydroptilidae 188, 201Hydrozoa 34, 35Hygrobia 108Hygrobiidae 108Hymenosomatidae 77, 79, 81Hynes, H.B.N. 13Hypogastruridae 85Hyridella 50Hyriidae 50

Ictinogomphus australis 177Illiesoperla 185insects 10Irpacaenis 138Ischnura 162, 164, 165, 167

aurora 167heterosticta 162, 164, 167

Isidorella 56Isopoda 68, 72Isostictidae 164, 169

Janiridae 72Jappa 141jargon 16, 17jellyfish, freshwater 34job descriptions, ecological 7

Kempyninae 90key

to amphipods 71to beetles 94–95to caddisflies 190–191to decapods 78to dragonflies and damselflies

166to mayflies 135to molluscs 48to stoneflies 182to true bugs 147to true flies 114–115

keystraps for young players 20

killer mayflies 136Kimminsoperla 186Kingdom 18


Kingolus 100Kirrama 185Kokiriidae 188, 202Koonunga 74Koonungidae 74Kosrheithrus 209Kutikina 55

labial palp 161labrum 187, 190, 191Laccotrephes 155lacewing larvae 90lakes 2Larinae 100, 101larvae 9, 10lateral humps 187Latin 17, 35, 41, 52, 93, 123leaf litter 8Lectrides 204leeches 9, 16, 41, 42, 43lentic habitats 1Lepidoptera 86, 134Lepidurus apus viridus 76Leptoceridae 9, 14,188, 189, 192,

203, 204Leptoconopinae 119leptoflebs 140Leptoperla 185Leptophlebiidae 134, 140, 141Leptopodidae 146Lestidae 164, 170Lethocerus 148Libellulidae 162, 163, 164, 175,

176life cycle 9, 35, 55, 93, 103, 104,

110, 116, 134, 148, 153, 160,184, 185, 186

larval 10nymphal 10

Limnadia 66Limnadopsis 66Limnephilidae 188, 205Limnocharidae 60Limnoxenus 107limpet, giant 56limpet, freshwater 51, 52Lindeniidae 164, 176, 177Lingora 196little basket shells 49Livingstone, Dr. 13long jawed spiders 62lotic habitats 1Lumbriculidae 44Lumbriculus variegatus 44, 45Lycosidae 60Lymnaea 55

Lymnaeidae 47, 54, 55Macrobrachium 78, 81

australiense 81Macrogyrus 103macroinvertebrate groups 20macrophytes 7maggots 115, 116mandible 187, 190march flies 124Marillia fusca 206

bola 206fusca 206

marron 78marsh beetles 111marsh flies 113, 126, 127marshes 3marsupium 71Matasia 196maxillae 187maxillary palps 92mayflies 14, 16, 18, 17, 131–143,

164, 180, 182Mecoptera 88medical entomology 13medusa 34, 35Megadrili 44Megaloprepus coerulatus 178Megaloptera 7, 89Megapodagrionidae 163, 164, 171Megaporus 98meniscus midges 123mentum 112Merragata 160mesonotum 187mesosternum 187Mesostoma 39mesothorax 17Mesovelia hungerfordi 160Mesoveliidae 159, 160metanotum 187metasternum 187metathorax 17Miall, L.C. 16microcaddis 201microcrustaceans 63Microdrili 44Micronecta 150Microsporidae 96Microvelia 160’mids 120Mirawara 136Miss Muffet 16mites 13, 59, 60Mollusca 42, 46–58, 126mosquitoes 2, 13, 113, 122, 123moth flies 128

Motobdella 42Moufet, Thomas 16movable hook 161mudeyes 163Muscidae 126mussels 47, 50

Naididae 44Nais 44Nannochorista 88Nannochoristidae 88Nannophya dalei 176Naucoridae 154Neboissoperla, 185Necterosoma 99needle bugs 155nematocysts 35Nematoda 36Nematomorpha 37Nemertea 37Neoniphargidae 70, 71Nepa 16Nepidae 155, 156Nepinae 155Nerthra 151Nescioperla 185net spinning caddis 191, 200nets 3net-winged midges 118Neuroptera 90Neurorthidae 90, 91Newmanoperla 185Niphta 130nitrogen 9non-biting midges 15, 113, 120Nososticta solida 172Notalina 204

spira 203Noteridae 96Nothoderus 130Nothodixa 123Notoaeschna sagittata 174Notonectidae 146, 157, 158Notonemoura 181, 186Notonemouridae 181, 186Notopala 52, 53

hanleyi 53Notostraca 68, 76Notriolus 100, 101Nousia 18, 133, 141

parva 18nursery web spiders 60nutrients 8, 9, 43nymphs 9, 11Nymphulinae 86

Index l 231

Ochteridae 145, 146Ochthebius 104Odonata 7, 18, 134, 161–179Odontoceridae 188, 206Oecetis 189, 204, 203Oeconesidae 188, 207Offadens 137Oligochaeta 44, 45Oniscidae 72Oniscidea 72Oniscigastridae 132, 142Onychohydrus scutellaris 96operculum 47, 52, 53, 54, 56, 58,

100Order 18organic pollution 13Ornithobdellidae 42Orthocladiinae 120, 121Orthotrichia 201Osmylidae 90, 91Ostracoda 67Ovolara 101Ozobranchidae 42

Palaemon 81Palaemonetes 81Palaemonidae 78, 79, 81Palaeocaridacea 73Paracalliope 70Paracalliopiidae 69, 70, 71Paramelitidae 70, 71Paranaspides 74Paranyctiophylax 211Parapistomyia 118Paraplea 158Parartemia 75Parastacidae 8, 79, 82Parastacoides 74, 79, 83Paratya australiensis 80pea shells 51peduncle 68periphyton 7, 51, 52, 55, 58, 118Petalura 178

gigantea 178ingentissima 178

Petaluridae 164, 178phantom midges 13, 123Philopotamidae 189, 201, 208Philorheithridae 189, 208, 209phosphorous 9Phreatoicidea 69, 72Phreodrilidae 44Phylum 18Physa acuta 48, 56Physidae 47, 56Pisauridae 60, 61

Pisidium 51plankton 64, 79, 202Planorbarius 56Planorbidae 47, 56plastron 96, 97, 101, 105Plecoptera 180–186Plectrocnemia 210Plectrotarsidae 188, 210Plectrotarsus 210Pleidae 158pleopods 68Podonominae 120, 121pogs 119pollution 18, 42, 45, 116, 139,

145, 164Polycentropodidae 189, 210, 211polyp 34, 35Pomatiopsidae 57pond snails 54ponds 2pools 1Porifera 9, 32postmentum 161Potamophilinus 100Potamopyrgus antipodarum 48, 54prawns 77, 79, 80, 81predators 7prementum 161premental setae 161preservation and labelling 5primitive dragonflies 164Prionocyphon 111Pristina 45Procordulia jacksoniensis 176producers 7pro-legs 112pronotum 187prosternum 187Protochauliodes 89Protoneuridae 164, 172Psammaspididae 74Psephenidae 93, 109Pseudomoera 69, 70Pseudosuccinea columella 55Psychodidae 128Psychomiidae 189Ptilodactylidae 93, 110pupae 10, 11, 101, 201purple perils 136Pygmanisus 56pygmy backswimmers 158Pyralidae 86

Radinocerus 130radula 46, 49, 55ramus (rami) 68

Ranatra 155Ranatrinae 155rat-tailed maggots 126, 127red spinners 15, 141reproduction 9Rhadinosticta simplex 169Rhantus suturalis 99Rheotanytarsus 121Rheumatometra 152Rheumatometroides 152Richardsonianus 41–43Riekoperla 185riffle beetles 100riffles 1river health 16rivers 1Ross, I.C. 55round worms 36runs 1

Saldidae 146sand flies 119Sayce 16Sciomyzidae 112, 113, 126, 127Scirtes 111Scirtidae 93, 111Sclerocyphon 109scorpionfly larvae 88scrapers 7screech beetles 108scuds 69sculptured snails 58scutellum 92sea monkeys 75seed shrimp 67seeps 1segmented worms 44sexual reproduction 9, 55Sharp 16shield shrimp 76shredders 7shrimp 13, 72, 73, 75, 77, 78, 79,

80, 81Sialidae 89side swimmers 69Sigara 150SIGNAL 19silk 189silk organ 190Simocephalus 63–64Simsonia 100Simuliidae 9, 13, 113, 115, 116,

129Simulium 129Siphlonuridae 143Sisyra 90


Sisyridae 90, 91sleeping bag caddis 193sludge worms 44small water striders 159Sminthuridae 85Sminthurides 85Smith 16snail-killer maggots 127snails 7, 9, 44, 47, 52, 53, 54, 55,

57, 58, 127, 198snail-shelled caddis 198soldier flies 128sow bugs 72Spathula 39Species 16, 18Sphaeriidae 47, 51Sphaerium 51Sphaeromatidae 72spiny nymphs 139spiracles 112sponge flies 90, 91sponges 9, 32, 33, 91Spongillidae 32springs 1springtails 84, 85Staphylinidae 96statocyst 79statolith 79Stempellina 121Stenochironomus 120Stenopsychidae 188Stenosialis australiensis 89Stetholus 101stick caddis 203stoneflies 16, 17, 180–186Stratiomyidae 128stream horses 139streams 1Striadorbis 53Stygocarididae 74Styloniscidae 72sub imago 132, 133Succineidae 55Sundathelphusidae 79swamp spiders 60swamps 3swimming hairs 59, 92, 98, 104,

106, 132, 149Symphypleona 85Symphitoneuria opposita 203Syncarida 68, 73, 74Synlestes 173

weyersii 163, 173

Synlestidae 164, 173Synthemidae 165, 176Synthemiopsis 175Synthemistidae 164, 175Syrphidae 113, 116, 126, 127

Tabanidae 13, 113, 124tadpole shrimp 76Talitridae 69, 71Tamasia 195Tanyderidae 116, 130Tanypodinae 115, 120, 121tarsus (tarsi) 144, 161Taschorema 199Tascuna 207Tasiagma 212Tasimia 211, 212Tasimiidae 189, 211Taskiria otwayensis 202Tasmanocerca 186Tasmanocoenis 134, 138, 139Tasmanoperla 183Tasmanophlebia 142Tasmanthrus 208Tasmodorbis 53taxonomic names 18taxonomy 16Telephlebia 174Telephlebiidae 164, 174telson 68Temnocephala 38temnocephalans 36, 38Tenagogerris 152terminal filament 131terminal gills 166Tetragnatha 62Tetragnathidae 62Thaumaleidae 130Thaumatoperla 184Thiara 58Thiaridae 58Thomson 16tibia 144, 161tiger leech 41, 42Tillyard 16Tillyardophlebia 141Tipulidae 10, 113, 115, 124, 125toad bugs 151toebiters 89tools, bug picking 4Trichoptera 15, 187–212Trinotoperla 181, 185

minor 12

Triops australiensis australiensis 76Triplectides 203, 204true bugs 12, 144–160true flies 13, 62, 112–130, 164Tubificidae 44–45Turbellaria 9, 39Tympanogaster 104, 105‘U’ bent larvae 123Ulmerochorema 199Ulmerophlebia 141Uramphisopus 73uropods 68Urothemistidae 164, 175

Velesunio 47, 50Veliidae 159, 160velvet water bugs 144, 159ventral apotome 187Viviparidae 52vulture caddis 192

Walton, Izaak 14water beetles 13, 16water fleas 63water measurers 153water pennies 109water scavenger beetles 93, 106water scorpions 16, 144, 146, 155,

156water slaters 72water striders 113, 144–146, 152,

160water treaders 159waterboatmen 149welts 112Westriplectes 204Westwood 16wetlands 3whirligig beetles 102wing buds 11, 131, 161, 180wings 12wolf spiders 60, 61worms 16, 36, 37, 38, 42, 44, 45,

127wrigglers 122Wundacaenis 138

yabbies 8, 13, 78, 82, 83

Zavreliella 121Zygoptera 164, 167–173

waterbug book a guide to the freshwater macroinvertebrates of temperate australia

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