Purdue extension4-H-1019

Bioindicators of Water QualityQuick–Reference Guide

Authors: Julie Speelman and Natalie Carroll | Photographer (unless otherwise noted): Julie Speelman | Design and Layout: Jennifer Mazonas

This publication shows aquatic insects that can be used as bioindicators of water quality in Indiana waterways. Bioindicators are biological systems that are sensitive to environmental changes and, therefore, can indicate when pollution is present in the water.

A tolerance score is included for each insect in this publication. The tolerance score, ranging from 0–10, represents the insect’s sensitivity to pollution and can be used to estimate the quality of the water in which the insect was found. Insects with a score of 0 are intolerant to pollution, meaning they cannot tolerate any water pollution, while insects with a score of 10 are very tolerant of polluted water.

Materials Needed• dipnet• whiteplasticpail,bowl,ordishpan(Note:Thewhitecolormakesiteasier

to see the insects.)• 2–3whitestyrofoameggcartonsorplasticicecubetrays• datasheet—availableonlineat:www.four-h.purdue.edu/natural_

resources/ (select“ResourcesforEducators”and“Bioindicators”)

Instructions• Locateabodyofwater(e.g.,stream,pond,lake)tosample.Thewatershouldonlybeatmostkneedeepandalloweasyaccessforobtainingthesample.Makesureyouhavepermissiontosamplethewater.

• Dipthepailinthewatertobesampled.• Collectinsectsamplesfromallhabitatswithina200-footsection

of that body of water, and place them in the pail. Jab your dip net against the vegetation and into mud or sand at the bottom to collectinsects.Scrapetheundersideofrocksandlogsintothenet.

• Collectinsectsfor45minutes.• Usingtheicecubetray,sorttheinsectsthatlookthesameintothe

different compartments of the tray using your hand or forceps. Be suretoputsomewaterintheicecubetrayfirsttokeeptheinsectsfrom drying out.

• Usethebioindicatorflashcardsorquickreferenceguidetoidentifytheinsects.Recordthenumberofinsectsfromeachinsectfamilyyouidentify on the data sheet.

• Placetheinsectsbackinthewaterwhenyouarefinished.• Completethecalculationsdescribedinthenextsectiontodetermine

the quality rating.

Assessing the Water Quality of a SiteFor each insect family group:• Recordthenumberofinsectsfoundforeachspecieslisted.• MultiplytheToleranceValuebytheNumberFound,andentertheresultunderFamilyToleranceScore.

• SumtheNumberFoundandFamilyToleranceScorecolumns(OrderTotals).

For each insect order:• TransfertheOrderTotalstotheOrderSummarysection.• SumtheNumberFoundandOrderToleranceScorecolumns (GrandTotal).

• DeterminetheBioticIndexbydividingtheGrandTotalToleranceScorebytheGrandTotalNumberFound.

• Usethebioticindexinthetableprovidedtoestimatethewaterquality rating and degree of organic pollution.

Biotic Index

Water Quality Rating

Degree of Organic Pollution

0.00–3.75 excellentorganic pollution unlikely

3.76–4.25 very goodslight organic pollution possible

4.26–5.00 goodsome organic pollution probable

5.01–5.75 fairfairly substantial pollution likely

5.76–6.50 fairly poor substantial pollution likely

6.51–7.25 poor very substantial pollution likely

7.26–10.0 very poorsevere organic pollution likely

Resources• U.S.EnvironmentalProtectionAgency(EPA)• AboutBiologicalIntegrityandIndicators:

www.epa.gov/bioindicators/html/about.html• InvertebratesasIndicators(lookforBugsasIndicatorsofWaterQuality):

www.epa.gov/bioindicators/html/invertebrate.html• Bugguide.net(hostedbyIowaStateUniversityEntomology):

www.bugguide.net

• HoosierRiverwatch(providestrainingonthisandmanyotherwater-relatedtopics):http://www.in.gov/dnr/nrec/3046.htm

• VolunteerStreamMonitoringTrainingManual(download,13.7MB):http://www.in.gov/dnr/nrec/files/nc-Riverwatch_Manual.pdf;Chapter5covers biological monitoring.

• HoosierRiverwatcheventscalendar:http://www.in.gov/dnr/nrec/

ColeopteraBeetles

Dryopidae Long-toed Water Beetle Diptera

Flies

5

Dytiscidae (larvae)Predaceous Diving Beetle

5

Gyrinidae (larvae)Whirligig Beetle

4

Gyrinidae(adult)Whirligig Beetle

4

Dytiscidae(adult)Predaceous Diving Beetle

5Haliplidae (larvae)

Crawling Water Beetle

7

Elmidae(larvae)Riffle Beetle

5Haliplidae(adult)

Crawling Water Beetle

7

Elmidae(adult)Riffle Beetle

5 Hydrophilidae (larvae)Water Scavenger Beetle

5

Hydrophilidae(adult)Water Scavenger Beetle

5

Psephenidae (larvae)Water Penny

4

ChaoboridaePhantom Midge

8

ChironomidaeNon-biting Midge

6 pale forms

8 red forms

CulicidaeMosquito

8

AthericidaeAquatic Snipe Fly

2

DixidaeDixid Midge

1

BlephariceridaeNet-winged Midge

0

CeratopogonidaeBiting Midge

6

EmpididaeAquatic Dance Fly

6

MuscidaeHouse Fly, Stable Fly,

Green Bottle Fly

6Ephydridae

Shore Fly

6

EphemeropteraMayflies

SimuliidaeBlack Fly

6

SciomyzidaeMarsh Fly

6

PsychodidaeMoth Fly

10

StratiomyidaeSoldier Fly

8

SyrphidaeRattailed Maggot

10

TabanidaeHorse Fly, Deer Fly

6

TipulidaeCrane Fly

3

IsonychiidaeBrushed-legged Mayfly

2

LeptohyphidaeLittle Stout Crawler Mayfly

4

LeptophlebiidaeProng-gilled Mayfly

2

PolymitarcyidaePale Burrowing Mayfly

2

PotamanthidaeHacklegill Mayfly

4

HeptageniidaeFlat-headed Mayfly

4Ephemeridae

Common Burrowing Mayfly

4

EphemerellidaeSpiny Crawler Mayfly

1

BaetidaeSmall Minnow Mayfly

4

BaetiscidaeArmored Mayfly

3

CaenidaeSmall Square-gill Mayfly

7

SiphlonuridaePrimitive Minnow Mayfly

7

HemipteraAquatic Bugs

GelastocoridaeToad Bug

Undetermined

BelostomatidaeGiant Water Bug

10

CorixidaeWater Boatman

9

LepidopteraAquatic Moths

MegalopteraAlderflies,

Dobsonflies, and Fishflies

CorydalidaeDobsonfly

OdonataDamselflies and

Dragonflies

AeshnidaeDarner

HebridaeVelvet Water Bug

Undetermined

MesoveliidaeWater Treader

Undetermined

HydrometridaeWater Measurer

Undetermined

PleidaePygmy Backswimmer

Undetermined

SaldidaeShore Bug

Undetermined

VeliidaeBroad-shouldered Water Strider

NotonectidaeBackswimmer

Undetermined

GerridaeWater Strider

Undetermined

NepidaeWater Scorpion

8Naucoridae

Creeping Water Bug

5

PyralidaeAquatic Caterpillar

5Calopterygidae

Broad-winged Damselfly

5

3

SialidaeAlderfly

4

0

GomphidaeClub-tailed Dragonfly

1

CoenagrionidaeNarrow-winged Damselfly

9

LestidaeSpread-winged Damselfly

9

LibellulidaeCommon Skimmer

7

Photo

: Dr. J

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Photo

: Dr. J

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Photo

: Dr. J

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6

PlecopteraStoneflies

TrichopteraCaddisflies

CapniidaeSmall Winter Stonefly

1

NemouridaeBrown Stonefly

2

PteronarcyidaeGiant Stonefly

0

PerlodidaePatterned Stonefly

2

PerlidaeCommon Stonefly

1

LeuctridaeRoll-winged Stonefly

0

TaeniopterygidaeWinter Stonefly

2

BrachycentridaeHumpless Casemaker Caddisfly

1

GlossosomatidaeSaddle Casemaker Caddisfly

0

HelicopsychidaeSnail Casemaker Caddisfly

3

HydropsychidaeCommon Net Spinner Caddisfly

4

PhilopotamidaeFinger Net Caddisfly

3

LimnephilidaeNorthern Casemaker Caddisfly

4

LeptoceridaeLong Horned Casemaker

4

LepidostomatidaeLepidostomatid Casemaker

1

HydroptilidaeMicro Caddisfly

4

PhryganeidaeGiant Casemaker Caddisfly

4

ColeopteraBeetles

DryopidaeLong-toed Water Beetle

Dytiscidae (larvae)Predaceous Diving Beetle

5

Dytiscidae (adult)Predaceous Diving Beetle

5

Using this guide with the data sheets

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Order SummaryOrder Total

ColeopteraDipteraEphemeropteraHemipteraLepidopteraMegalopteraOdonataPlecopteraTrichoptera

Grand Total

Number Found Order Tolerance56852030635 155

240130027283825

BiotoicIndex=[GrandTotalTolerance]/[GrandTotalNumberFound]=155/35=4.43

Coleoptera (Beetles)

Family Tolerance Value

Number Found

Family Tolerance Score

DryopidaeDytiscidaeElmidaeGyrinidaeHaliplidaeHydrophilidaePsephenidae

5554754

Order Total 50300020 0

1000015025

Tolerance Value

FamilyName

CommonName

5