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FRESHWATER MACROINVERTEBRATES

byMohd Fairus Jalil and Arman Hadi Mohamed

Introduction

Aquatic insects can be found in essentially all types of water, from the largest lakes and rivers todiscarded tires, and even the water that accumulates in pitcher plants. These insects form an integralpart of aquatic ecosystems. They recycle much of the decaying plant and animal material back intothe food web. They are important food for fish and waterfowl. When they emerge from the water theadults are important food for insectivorous birds, mammals etc.. Many of the familiar biting insects(mosquitoes, midges etc.) start their life cycles in the lakes, ponds, rivers and streams.

Even though aquatic insects are important to the aquatic ecosystems of the state and bioassessmentsthere are still large gaps in our knowledge of the Bornean/Sabah fauna. A number of groups (Diptera:Culicidae, Odonata: Anisoptera) are relatively well known but further research to refine their distributionpatterns, record additional species and improve our knowledge of their ecology is needed. Somegroups (Trichoptera, Odonata) are well known only from certain habitats and still require more extensiveresearch to completely document their occurence in the state. Other groups are only known superficiallyfrom Borneo.

Sampling Immature Insects in Small Streams and Ponds

Equipment to sample aquatic insects typically can be used in both standing and flowing water. Sincemany samping devices must be hand-held, water depth is usually the factor limiting use.

The most commonly used device for sampling aquatic insects is the D-frame net (Fig. 1a). Insectscan be sampled in lakes or ponds by forcing the net through vegetation or surface layers of substrate.In streams, insects may be sampled by holding the D-net or hand screen collector downstream whilethe substrate immediately upstream is agitated by foot.

The Surber sampler (Fig. 1b) is another commonly used device for sampling aquatic insects. Thedevice is plaed with the opening facing upstream, while substrate immediately in front of the openingis agitated, thus dislodging materials - which float downstream into the net. Larger substrate, coatedwith algae, etc., should be held in th net opening and scrubbed with a brush to dislodge attachedinsects. A limitation of the Surber sampler can result from back-pressure in the net, caused by cloggingof the mesh openings, which sometimes causes material to escape.

Introductory Course To Entomology

Figure 1.a. D-frame net, b. Surber sampler

To make collections in ponds and along lake shores the net is passed through the weeds and openwater. In streams and rivers the net can be held downstream of the feet and the feet shuffled todislodge pebbles and small stones. Insects on the stones will fall off and be carried by the current intothe net. The net is then swirled in the water to remove fine silt and mud. The contents of the net arethen dumped into the pan with about 2 cm of water in it. The insects will be seen crawling out ofvegetation, sticks and pebbles and can be easily picked up with forceps or a small net and transferredto a vial or small jar with preservative. Insects can also be collected from logs and stones in the waterby hand. Notes about the sample and sample location should also be made in a field note book forfuture reference. A photograph of the habitat may also provide useful information.

Preserving & Labelling

The alcohol should be changed after 24 to 48 hours to ensure the specimens will be thoroughlypreserved and not start decomposing. If the jar has a large number of specimens or large specimensin it the alcohol may have to be changed a number of times to ensure proper preservation. Small vialsare ideal for storing sorted insects. The sorted insects are preserved in 75% alcohol so they will notbecome decomposed. A proper label of the location, collection date and name of collector is includedin each of the vials with the name of the specimen if it has been identified, for example.

MALAYSIA: SABAHSg. Bole (KM 51), Lembah Danum22.XI.2001. (under the stone)leg. Fairus J.M.

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Freshwater Macroinvertebrates

Tropic Groups

Of the trophic groups that Merritt & Cummins (1996) have identified for aquatic insects, only 5 arelikely to be found in a stream using typical collection and sorting methods:

1. Shredders - These have strong, sharp mouthparts that allow them to shred and chew live plantsor decomposing fragments. These are common among true flies, caddisflies, and stoneflies.

2. Collectors - These gather the very finest suspended matter in the water. To do this, they oftensieve the water through rows of tiny hairs. These sieves of hairs may be displayed in fans on theirheads (blackfly larvae) or on their forelegs (some mayflies). Some caddisflies and midges spin nets,and catch their food in them as the water flows through.

3. Scrapers - These scrape the algae and diatoms off of surfaces of rocks and debris, using theirmouthparts. Many mayflies, caddisflies, and true flies eat this way.

4. Piercers - These herbivores pierce plant tissues or cells and suck the fluids out. Some caddisfliesdo this.

5. Predators - Predators eat other living creatures. Some of these are engulfers; that is, they eattheir prey whole or in parts. This is very common in stoneflies and dragonflies, as well as caddisflies.Other are piercers, which are like the herbivorous piercers except that they are eating live animaltissues.

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Order Ephemeroptera (Mayflies)

Mayflies are hemimetabolous insects well known for their short-lived (ephemeral) adult phase, whichusually lasts from two hours to three days.

Mayfly nymphs go through a large number of moults as they grow, with most species having 15 - 25instars.

Mayfly nymphs exhibit considerable diversity in appearance although many stream species are dorso-ventrally flattened. The head bears a pair of compound eyes together with three ocelli and a pair ofantennae. The mouthparts, are well developed (as the nymph is the only feeding stage in the lifecycle). The mandibles of carnivorous species may be sickle shaped. The nymphal thorax is large andthe meso- and meta-thoracic segments are fused. The dorsal surface is heavily chitinized but has amedian suture line running down its length which eventually splits to allow emergence of the subimago.Two pairs of wing buds are visible on the meso- and metathorax flattened, like the body, in streamspecies - possibly an adaptation that brings the nymph close to the substrate surface thus reducingthe force of the current. Most segments have spines and marginal fringes of hairs and each tarsusends in a single, but substantial, claw used to cling to rock surfaces.

The nymphal abdomen is frequently also flattened and tapers towards the posterior. There are tendistinct segments and the postero-lateral corners of each commonly bear large spines. Gills are present,in pairs, as large plate-like structures, or tufts, on up to the first seven segments, depending onspecies. In a few families (e.g. the Caenidae and Tricorythidae), the gill plates on the second abdominalsegment have become enlarged to form a pair of opercula that protect the other fills from damage insilty environments. During this stage two or three long, sensory filaments arise from the tenth segment.

Life forms of mayfly larvae are diverse, but they fall into four broad categories: burrowing, flattened,swimming, and creeping.

They reach peak abundance in cool, clean headwater streams, where they are an important source offood for fish. Mayfly numphs are characteristic of shallow streams and littoral areas of lakes, and aredistributed widely.

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Table 1: Typical nymphal habitats of the families of Ephemeroptera (Williams & Feltmate, 1992)

FAMILY PRIMARY DISTRIBUTION HABITAT

Baetidae Widespread chiefly running waterCaenidae Widespread lotic-deposit/lentic-littEphemerellidae Widespread cheifly running waterEphemeridae Oriental/Afrotropical/Holorctic.. lotic & lentic burrowersHeptageniidae Largely Holarctic lotic & lentic-erosionalLeptophlebiidae esp. S. Hemisphere/some Holarc. & Orient esp. fast-flowing watersNeoephemeridae Holarctic & Oriental lotic-depositionalOligoneuriidae esp. Afrotr/Neotrop/some Holarc. & Orient running waterPolymitarcyidae esp. Neotrop./Afrotr./some in Holarctic burrowers in stream & river bedsPotamanthidae largely Asian/some N.A. lotic-depositionalTricorythidae esp. Afrotrotropical/>Neotropical lotic-deposit/lentic littoral

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Classification(Adapted from Morse et al. 1994; Williams & Feltmate, 1992; Edmunds & Polhemus, 1990)

Order EPHEMEROPTERA

Family AcanthametropodidaeFamily AmeletidaeFamily AmetropodidaeFamily AmoletopsidaeFamily AnaletrididaeFamily Baetidae*Family BaetiscidaeFamily BehningiidaeFamily Caenidae*Family ColoburiscidaeFamily Ephemerellidae*Family Ephemeridae*Family Heptageniidae*Family IsonychiidaeFamily Leptophlebiidae*Family MetamoniidaeFamily MetretopodidaeFamily Neoephemeridae*Family Oligoneuridae*Family OniscigastridaeFamily Polymitarcyidae*Family Potamanthidae*Family ProssopistomatidaeFamily PseudironidaeFamily RallidentidaeFamily SiphalaenigmatidaeFamily SiphlonuridaeFamily Tricorythidae*

*Families with known Malaysian/Bornean representatives

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Quick Guide For Identification: Ephemeroptera(Adapted from Morse et al. 1994)

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A typical Ephemetoptera


Order Plecoptera (Stoneflies)

The stoneflies are terrestrial as adults, but in the nymphal stages they are strictly aquatic, and mostare restricted to flowing waters of relatively high oxygen concentrations. The nymphal instars, from10 to over 30 moltings, occur in one to three years. Adults live from 1 to 4 weeks.

Plecopteran nymphs are restricted to cool, clean streams with high dissolved oxygen content.

Generally, stonefly nymnphs are either shredders or predators. Some groups that are predaceous aslate instars have been reported to be herbivorous or detritivorous in early instars, while late instars oflarge detritivores may consume some prey.

Classification(Adapted from Morse et al. 1994; Williams & Feltmate, 1992)

Order PLECOPTERAFamily AustroperlidaeFamily Capniidae*Family ChloroperlidaeFamily DiamphipnoideaFamily EustheniidaeFamily GripopterygidaeFamily LeuctridaeFamily Nemouridae*Family NotonemouridaeFamily Peotoperlidae*Family Perlidae*Family Perlodidae*Family PteronarcyidaeFamily ScopuridaeFamily Taeniopterygidae

*Families with known Malaysian/Bornean representatives.

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Quick Guide for Identification: Plecoptera(Adapted from Morse et al. 1994)

a. Dorsal view of larva ofIsoperla sp. (Perlodidae)

b. Dorsal view of larva of Pteronarcyssp. (Pteronarcyidae)


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Order Trichoptera (Caddisflies)

Caddisflies are holometabolous insects whose eggs are deposited in gelatinous matrices in or out ofwater. Larvae go through 5 instars. Adults live from a few weeks to several months, depending on thespecies and the nature of the habitat.

Caddisfly larvae are quite similar to lepidopteran caterpillars but have only a single pair of abdominalprolegs which are located on the terminal segment and are each equipped with an apical anal claw.The larval thorax is well developed, with at least the pronotum covered dorsally by a pair of sclerotizedplates.

Examples of the diversity in caddisfly larval cases: A: Phryganeidae, B. Limnephilidae, C. Uenoidae,D. Hydroptilidae, E. Molannidae.

A B C

D E


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Although caddisfly larvae are found in a wide range of aquatic habitats, the greatest diversity occurs in coolrunning waters.

Table 1. distribution of the families of Trichoptera, together with typical larval habitats (Williams & Feltmate,1992)

Family Distribution and Habitat

Brachycentridae Confined to Nearctic, Palaearctic & Oriental regions; running waters (coolstreams to large rivers, depending on genus)

Calamoceratidae All regions (but sparse), but mainly subtropical; slow streams, coastallakes, swamps; phytotelmata

Dipseudopsidae A frotropical & Oriental regions (1 genus in the Nearctic); lakes &slow-flowing waters

Ecnomidae All regions except the Nearctic; lakes, ponds & slow-flowing waters

Glossosomatidae Cosmopolita; running waters

Goeridae All regions except Australian & Neotropical; running waters, especiallyspring seeps

Helicopsychidae Cosmopolitan, but with greater diversity in tropics; cool & warm runningwaters; littoral zone of lakes

Hydrobiosidae Mainly confined to Australian & Neotropical regions; running waters

Hydropsychidae Cosmopolitan; running waters & wave-swept shores of lakes

Hydroptilidae Cosmopolitan; running & standing waters

Lepidostomatidae All regions except Australian, but in Neotropical only in montane CentralAmerica, not South America; mainly slow, cool running waters; littoral oflakes

Leptoceridae All regions (abundant); mainly standing waters; slower sections of rivers

Limnocentropodidae Oriental Region & Japan; rapid streams

Philopotamidae Cosmopolitan; running waters


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Polycentropodidae Cosmopolitan; running & standing waters

Psychomyiidae All regions except Australian & Neotropical; cool running waters, some inlakes

Rhyacophilidae All major zoogeographical zones except Australian, Neotropical,Afrotropical & the Antarctica; in cool running waters

Stenosychidae Oriental, Australian, Afrotrop. & Asian Palaearctic regions; fast-flowingrivers

Xiphocentronidae Afrotropical, Oriental, Neotropical & extreme south of Nearctic(Mexico, Texas); small streams


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Classification(Adapted from Morse et al, 1994; Williams & Feltmate, 1992)

Order TRICHOPTERAFamily AntipodoeciidaeFamily AtriplectididaeFamily BeraeidaeFamily Brachycentridae*Family Calamoceratidae*Family CalocidaeFamily ChathamiidaeFamily ConoesucidaeFamily Dipseudopsidae*Family Ecnomidae*Family Glossosomatidae*Family Goeridae*Family HelicophidaeFamily Helicopsychidae*Family Hydrobiosidae*Family Hydropsychidae*Family Hydroptilidae*Family KokiriidaeFamilyLepidostomatidae*Family Leptoceridae*Family LimnephilidaeFamily Limnocentropodidae*Family MolannidaeFamily OdontoceridaeFamily OeconesidaeFamily Philopotamidae*Family PhilorheithridaeFamily PhryganeidaeFamily PhryganopsychidaeFamily PlectrotarsidaeFamily Polycentropodidae*Family Psychomyiidae*Family Rhyacophilidae*Family SericostomatidaeFamily Stenopsychidae*Family TasimiidaeFamily ThremmatidaeFamily UenoidaeFamily Xiphocentronidae*

*Family with known Malaysian/Bornean representatives.


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Quick Guide for Identificaton: Trichoptera(Adapted from Morse et al. 1994 & CSIRO, 1991)

Lateral view of larva (Limnephilidae)

Prothorax

Mesothorax

Metathorax

Dorsalhump

Lateral hump

Dorsalsclerite

Analproleg

Lateral sclerite

Anal claw

Anal claw

accessory hook


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Order Odonata (Dragonflies and Damselflies)

Odonates comprise two suborders, the Anisoptera (dragonflies) and Zygoptera (damselflies). Thetaxonomy of this order is relatively well known among the aquatic insects, since numphs (or naiads)are typically very conspicuous and well studied.

Odonates are hemimetabolous, with relatively long-lived adults (several weeks to several months).

Characteristics of dragonfly and damselfly larvae include:♦ Large eyes♦ 3 pairs of long sefmented legs on upper middle section (thorax) of body♦ Large scoop-like lower lip that covers bottom of mouth♦ No gills on sides or underneath of abdomen

Table 1: Differences between the Anisoptera and the Zygoptera (Williams & Feltmate, 1992) and(Kellogg, 1994)

A. Anisoptera (dragonflies)

Hindwings broader at base, heldhorizontally or slightly depressed at rest.Strong fliers.

Larvae- Wide oval to round abdomenthat may end in three wedge-shapedextensions

Eyes not projecting from sides of head.

Most families with reduced or vestigialovipositors.

Supra-anal plate present in males.

Nymphs robust, with rectal gills.

Eggs usually laid at water surface or onsurfaces of aquatic plants.

A. Zygoptera (damselfly)

Wings of equal size, narrow at base, heldvertically at rest. Weaker fliers.

Larvae- Narrow body with 3 oar-shapedtails (gills) extending in a tripod formation.Long spindly legs and a thin narrow body.

Eyes bulbous and prominent.

Females with well developed ovipositors.

Supra-anal plate vestigial.

Nymphs slender, with paddle-like caudalgills.

Eggs inserted into stems of aquatic plants.


Classification(Adapted from Lieftinck, 1954; Morse et al. 1994; Williams & Feltmate, 1992)

Order OdonataSurorder Anisoptera

Family Aeshnidae*Family AustropetaliidaeFamily ChlorogomphidaeFamily Cordulegasteridae*Family Corduliidae*Family Gomphidae*Family Libellulidae*Family Macromiidae*Family NeopetaliidaeFamily PetaluridaeFamily Synthemistidae

Suborder AnisozygopteraFamily Epiphlebiidae

Suborder ZygopteraFamily Amphiterygidae*Family Calopterygidae*Family ChlorismagrionidaeFamily Chlorocyphidae*Family Coenogrioniidae*Family CoryphagrionidaeFamily DicteriadidaeFamily DiphlebiidaeFamily Euphaeidae*Family HemiphlebiidaeFamily IsostictidaeFamily Lestidae*Family LestoideidaeFamily Megapodagriidae*Family PerilestidaeFamily Platycnemididae*Family Platystictidae*Family PolythoridaeFamily Protoneuridae*Family PseudostigmatidaeFamily SynlestidaeFamily Thaumatoneuridae

*Families with known Malaysian/Bornean representatives.

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Quick Guide For Identification: Odonata(Adapted from Morse et al. 1994; CSIRO, 1991)

Dorsal view of a zygopterous larva (Zygoptera)

Lateral view of an anisopterous larvae (Anisoptera)

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Order Hemiptera (Water or True Bugs)

Hemipterans are paurometabolous, undergoing incomplete, gradual metamorphosis from egg to nymphto adult.

Hemipterans are generally found in lentic habitats or in backwater or pool areas of streams. Sixfamilies are fully aquatic in all life history stages (true water bugs: Belostomatidae, Corixidae,Naucoridae, Nepidae, Notonectidae, and Pleidae). These families are classified as swimmers, clingers,or climbers. Two of them (Notonectidae and Pleidae) swim upside down (venter up) and have beengiven the common name, backswimmers. Four families are surface dwellers or skaters (Gerridae,Hydrometridae, Mesoveliidae, and Veliidae) and are thus semiaquatic. Four families are shore bugsand live along the edges of ponds or steams. Gelastocoridae, Hebridae, Ochteridae, and Saldidaecontain species classified as skaters, climbers, clingers, burrowers, or sprawlers.

Table 1: Families of Malaysian/Bornean Hemiptera that are associated with water and their habitat(Fernando & Cheng, 1963; Yang et al., 1994; Williams & Feltmate, 1992)

Family Habitat

Belostomatidae* (giant water bugs)- ponds, in vegetation

Corixidae* (water boatmen)- fesh & brackish lentic waters

Gerridae* (water striders)- surface of fresh & brackish waters (sea)

Hebridae* (velvet water bugs)- marshes & wet riparian mosses

Helotrephidae* ponds & lakes, in vegetation

Hydrometridae* (water measurers)- surface of calm waters

Mesoveliidae* (water treaders)- vegetated banks of ponds & lakes

Naucoridae* (creeping water bugs)- lentic & lotic, stones & vegetation

Nepidae* (water scorpions)- ponds, on vegetation

Notonectidae* (backswimmers)- ponds and lakes

Pleidae* (pygmy backswimmers)- ponds & lakes, in vegetation

Ranatridae* ?

Veliidae* (riffle bugs)- surface of ponds & streams, also brackish

References

CSIRO. 1991. The insects of australia: a textbook for students and research workers. Carlton,Victoria, Melbourne University Press. Fernando & Cheng 1963.

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Quick Guide For Identification: Aquatic Hemiptera(Adapted from Morse et al. 1994; CSIRO, 1991)


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Order Coleoptera (Aquatic Beetles)

Aquatic beetles occur in two major suborders, the Adephaga and the Polyphaga. Both larvae andadults of six beetle families are aquatic, Dytiscidae (predaceous diving beetles), Elmidae (riffles beetles),Gyrinidae (whirligig beetles), Haliplidae (crawling water beetles), Hydrophilidae (water scavengerbeetles), and Noteridae (burrowing water beetles). Five families, Chrysomelidae (leaf beetles),Limnichidae (marsh-loving beetles), Psephenidae (water pennies), Ptilodactylidae (toe-wingedbeetles), and Scirtidae (marsh beetles) have aquatic larvae and terrestrial adults, as do most of theother orders of aquatic insects; adult limnichids, however, readily submerge when disturbed. Threefamilies have species that are terrestrial as larvae and aquatic as adults, Curculionidae (weevils),Dryopidae (long-toed water beetles), and Hydraenidae (moss beetles), a highly unsual combinationamong insects.

Family Gyrinidae (Whirligig Beetle)Whirligig beetles are comnmon inhabitants and normally ae found on the surface in quiet pools.

Table 1: Families of Coleoptera that contain aquatic or semiaquatic species in Malaysia/Borneo(Fernando & Gatha, 1963; Williams & Feltmate, 1992)

FAMILY DISTRIBUTION & HABITAT

Amphizoidae* (Trout stream beetles)- fast streams, often on logs

Dryopidae* (long-toed water beetles)- shallow regions of ponds & lakes esp. in emergentvegetation; swift streams

Dytiscidae* (predaceous diving beetles)- ponds & lakes, esp. near vegetation; slowersections of running waters

Elmidae* (riffle beetles)- fast & slower sections of streams, wave-swept shores oflarge lakes; some species on shoreline

Gyrinidae* (whirligig beetles)- ponds & lakes, especially near vegetation; slower sectionsof streams & riverS

Haliplidae* (crawling beetles)- aquatic vegetation at the edges of ponds, lakes & slowstreams

Helodidae* (marsh beetles)- lentic & slow lotic waters, esp. near emergent vegetation;tree holes; springs

Hydraenidae* (moss beetles)- stream margins, ponds near emergent vegetation; hygropetric(wet rock surface) habitats; marine rockpools & intertidal

Hydrochidae* (water scavenger beetles)- on plants in ponds or slow streams


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FAMILY DISTRIBUTION & HABITAT

Hydrophilidae* (water scavenger beetles)- ponds & lakes, esp. near vegetation; slowersections of streams & rivers

Noteridae* (burrowing water beetles) shallow margins of standing or slow streams,often in mud or on plants

Psephenidae* (water pennies)- fast streams, wave-swept shores of large lakes

Ptilodactylidae* (toed-winged beetles)- fast & slow water regions of streams; stream marginsin leaf litter

Quick Guide For Identification: Aquatic Coleoptera(Adapted from Morse et al. 1994; CSIRO, 1991)


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Order Diptera (Flies, Mosquitoes, Midges)

Aquatic dipterans represent some of the best known insect forms, including mosquitoes, black flies,midges, crane flies and horse flies, many of which are the most troublesome of all insect pests,particularly in terms of human health and economics.

Approximately 10% of all dipteran species are aquatic in their larval stage. Eggs and pupae of thesespecies are also aquatic, whereas adults are always terrestrial.

Dipteran larvae occur in almost every conceivable aquatic habitat, from the bracts of pitcher plants(Culicidae: Wyeomyia), tree holes (e.g., Chironomidae and Culicidae), saturated soil, and mud puddles,to streams, ponds, large lakes, rivers, and even the marine rocky intertidal zone. Stratiomyids havebeen recorded from geyser-fed thermal pools that reach temperatures up to 49 deg. C, and ephydridsfrom natural seeps of crude petroleum. Dipterans are found in rushing streams (Blephariceridae,Deuterophlebiidae), stagnant pools, hot springs, and frozen sediments. The only aquatic habitatwhere dipterans have not been recorded is the open ocean.

They are classified as clingers, sprawlers, planktonic swimmers, burrowers, climbers, and miners.

Table 1: Examples of commonly found Diptean families of aquatic or semiaquatic, together withdescriptions of larval habitats (Williams & Feltmate, 1992)


Ceratopogonidae* (biting midges)- littoral & open water zones of lakes, also at margins esp.in algal mats; streams & rivers, esp. margins & in detritus; tree holes;temporary pools; moist soil; salt marshes; marine beaches; some speciesassociatied with pollution

Chaoboridae* (phantom midges)- lakes in profundal, littoral or open water zones; boggypools; temporary fresh waters; small springs, esp. limnocrenes

Chironomidae* (midges)- most types of waterbody, including intertidal rockpools & coralreefs; moist soil; phytotelmata; dung

Culicidae* (mosquitoes)- ponds & lakes; pools and slow sections of streams & rivers;bogs; marshes; woodland pools; temporary waters; salt marshes; marinerockpools phytotelmata; water tanks; small container habitats e.g. tin cans,tires, bottles, coconut shells


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Simuliidae* (black flies)- fast-water regions of streams & rivers; wave-swept, littoralzone of large lakes

Tipulidae* (crane flies)- fast & slow-flowing streams & rivers; springs; hygropetrichabitats; ponds & lakes, esp. in shallow ater; fresh & brackish watermarshes; wet moss; tree holes & other phytotelmata; marine intertidalzone; saturated soil; temporary pools; floodplains

Rhagionidae* (snipe flies)- moist soil & moss in woodlands

Tabanidae* (horse & deer flies)- wetlands; littoral zones & margins of ponds & lakes;damp soil; slow-water regions of stream & rivers; tree holes; marinebeaches; estuaries

Quick Guide For Identification: Aquatic Diptera(Adapted from Morse et al. 1994; CSIRO, 1991)


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Order Lepidoptera (Moths)

Lepidopterans are holometabolous and have 1 to 3 generations per year. Larvae of most species gothrough 4 or 5 instars before pupating underwater in silken cocoons spun inside either the larval case or theoval pupal case. Adults live for at most 2 weeks. The females of some species are larger than the males.

HABITAT AND DISTRIBUTION

Family Habitat

Pyralidae* lakes & ponds, on aquatic macrophytes (submerged & floating); emergent vegetation;rapid streams & rivers, on cobbles or bedrock; bog pools- includes both free-livingforms & leaf miners/stem borers


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Order Megaloptera (Alder-, Dobson- & Fishflies)

Larvae of all species of Megaloptera are aquatic and attain the largest size of all aquatic insects. Theadult Corydalidae are large, having a wing span of up to 16 cm (Megaloptera = “large wing”).

The metabolic consequences of this air bubble are unknown for most species. Megalopteran larvaego through 10-12 instars before crawling out of the water onto shore to pupate. Some have beenreported to pupate as far as 50 metres from the shore.

The larvae of the Corydalidae live in clear waters and are predaceous. The Sialidae are also widelydistributed but are confined to temperate latitudes. The larvae tend to live in more turbid waters, or atleast those with silty or muddy substrates; they prey upon smaller insects.

Classification

Order MEGALOPTERASuperfamily Corydaloidea

Family Corydalidae*Superfamily Sialoidea

Family Sialidae*Families with known Bornean representatives.


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Glossary

Abdomen-posterior section of the body, which is traditionally divided into head, thorax and abdomen,Antenna [plural Antenna] - “feeler”: sensory appendage on the head of many invertebratesusually in the form of a long thin, segmented filament.

Case-tubular construction of debris, cemented together by silk, made by some invertebrates (notablycaddis larvae) to provide camouflage and protection: this is portable-when the animal moveit takes its case with it.

Chrysalis-immobile pupal stage of some insects.Exoskeleton-the hardened “skin” of an arthropod used for rigidity against which the muscles can

pull: growth is accomplished by shedding this periodically by moulting.Filament-long thin “drawn-out” shape.Gills-organs that abstract oxygen from the water and release accumulated carbon dioxide (breathing).

They can take many groups: in primitive groups the whole body is a gill, some beetles use abubble of air as a physical gill. Many animals have leaf-like plates or tufts of filaments on theabdomen or thorax, which are used for this purpose.

Head capsule-the head of an insect with its hardened exoskeleton containing mouthparts, eyes,antennae etc.: particularly noticeable in those larvae which do not armour the thorax andabdomen, and are therefore soft-bodied and “work-like” maggots.

Jointed legs-arthropod legs with true articulating joints.Larva-juvenile stage of insects in which there is no pupal form; the adult emerges directly from the

last nymphal skin. Characteristically, each successive nymphal stage increasingly resemblesthe adult, each possessing larger wing pads (in which the developing wings are housed) thanthe one before. The earliest stages do not have wing pads.

Prolegs-soft, unjointed legs possessed by some invertebrates-may possess claws.Pupa-stage in which the metamorphosis from larva to adult takes place in some insect groups. Often

a passive stage (chrysalis), but in some groups (e.g. midges) the pupa remains active.Segmentation-sub-division of the body into a number of similar units marked by segment junctions

(e.g. earthworms, but also most higher forms).Spiracles-the floor of a stream or pool. [Latin substratum, pl. substrata]Thorax-”middle” section of the arthropod body which is conventionally divided into head, thorax

and abdomen.Trachea-tubes through which air is transported around the body of insects.Tube-silken construction of some invertebrates which is permanently attached to solid substrate or

permanently immersed in mud: this is not portable.Wing-cases-the hardened first pair of wings of some beetles and bugs which have been modified to

protect the second, membranous, pair which are used for flying.Wing pads-found on the thorax of insect nymphs, they enclose the developing wings.


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References

CSIRO. 1991. The insects of Australia: A text book for students and research and researchworkers. Carlton. Victoria, Melbourne University Press.

Edmunds, G.F. & Polhemus D.A. 1990. Chapter 5. Zoogeographical patterns among mayflies(Ephemeroptera) in the Malay Archipelago, with special refernce to Celebes. In Insects and therain forests of South East Asia (Wallacea). The Royal Entomological Society of London.

Fernando, C.H & Cheng 1963. A Guide to malayan Water Bugs (Hemiptera-Heteroptera) with keysto the genera, Department of Zoology, University of Singapore.

Fernando, C.H. & Gatha, S. 1963. Guide to families of Malayan Aquatic Coleoptera (with keysto the Genera of Dytiscidae and Gyrinidae and a list of species). Department of Zoology, Universityof Singapore.

Kellog, L.L. 1994. Save our streams. Monitor's Guide to Aquatic Macroinvertebrates. SecondEd. Izaak Walton League of America.

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freshwater macroinvertebrates - sabah macroinvertebrates.pdf · silty environments. during this...

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