INVERTEBRATE SAMPLING INVERTEBRATE SAMPLING METHODS METHODS

Therese A. CatanachTherese A. Catanach

Program in Ecology, Evolution, and Conservation1816 South Oak Street, MC 652

Champaign, IL 61820

Bugs in a Wildlife Class?Bugs in a Wildlife Class?

► Invertebrates provide food Invertebrates provide food for many wildlife and for many wildlife and game speciesgame species

► Perform many Perform many ecosystem servicesecosystem services

► Disease vectorsDisease vectors► Indicators of ecosystem healthIndicators of ecosystem health

Deciding the Scope of the QuestionDeciding the Scope of the Question

►What is the scope of your question?What is the scope of your question? General questionsGeneral questions

►Habitat survey: what insects live here?Habitat survey: what insects live here?►Impact of Impact of

managementmanagement Species related Species related

questionsquestions►Feeding surveysFeeding surveys►Prey availability Prey availability

surveysurvey

Invertebrate Natural HistoryInvertebrate Natural History

►Invertebrate natural Invertebrate natural history is importanthistory is important Presence does not equal Presence does not equal

availabilityavailability►SizeSize►Activity levelActivity level►Habitat preferencesHabitat preferences

Many invertebrates are Many invertebrates are toxic or mimic those that toxic or mimic those that areare

Considerations for Invertebrate Considerations for Invertebrate SamplingSampling

►Some insects more likely to Some insects more likely to

be caught in a certain trap be caught in a certain trap

than othersthan others Habitats frequentedHabitats frequented Activity periodsActivity periods Attractants used for trappingAttractants used for trapping

Sweep NetsSweep Nets

► Collect invertebrates in Collect invertebrates in vegetation or flyingvegetation or flying

► Difficult in thick vegetation Difficult in thick vegetation or when vegetation has or when vegetation has thorns/spinesthorns/spines

► Can be general or targetedCan be general or targeted HymenopteraHymenoptera DipteraDiptera HemipteraHemiptera LepidopteraLepidoptera OrthopteraOrthoptera ColeopteraColeoptera

► Not good for ground dwelling Not good for ground dwelling invertebratesinvertebrates

Malaise TrapsMalaise Traps

►Passive trap set up along flywaysPassive trap set up along flyways►Placement Placement

determines determines

catchcatch HymenopteraHymenoptera DipteraDiptera Some HemipteraSome Hemiptera Some ColeopteraSome Coleoptera

Flight Intercept TrapsFlight Intercept Traps

►Similar to Malaise TrapsSimilar to Malaise Traps►Targets insects that fall rather than climb when Targets insects that fall rather than climb when

barriers barriers

encounteredencountered BeetlesBeetles OrthopteraOrthoptera

Pan TrapsPan Traps

►Different colors attract Different colors attract different insectsdifferent insects

►Passive CollectingPassive Collecting DipteraDiptera HymenopteraHymenoptera HemipteraHemiptera

Sticky TrapsSticky Traps

►Standardized trapping effort if Standardized trapping effort if placed similarlyplaced similarly

►Positioning or damage can Positioning or damage can make identification challengingmake identification challenging

►TargetsTargets DipteraDiptera HymenopteraHymenoptera HemipteraHemiptera ColeopteraColeoptera

Vacuum DevicesVacuum Devices►Ideal for collecting in Ideal for collecting in

grassesgrasses►Separate invertebrates Separate invertebrates

from litter using from litter using emergence traps or by emergence traps or by handhand

►TargetsTargets HemipteraHemiptera HymenopteraHymenoptera DipteraDiptera

Light TrapsLight Traps

►Species must be Species must be attracted to lightattracted to light

►Different wavelengths Different wavelengths of light attract of light attract different taxadifferent taxa

►TargetsTargets LepidopteraLepidoptera ColeopteraColeoptera HemipteraHemiptera

Aquatic NetAquatic Net

► Many methodsMany methods Dragging through sedimentDragging through sediment Disturbing rocks and other Disturbing rocks and other

sheltersshelters► TargetsTargets

Immatures of many ordersImmatures of many orders Aquatic invertebratesAquatic invertebrates

Beat SheetsBeat Sheets

►Ideal forIdeal for

vegetation that’svegetation that’s

difficult to sweepdifficult to sweep ColeopteraColeoptera HemipteraHemiptera SpidersSpiders

Attractant TrapsAttractant Traps

►Uses attractants (C02, Uses attractants (C02, pheromones, fermenting pheromones, fermenting fruits, etc.)fruits, etc.)

►TargetsTargets MosquitoesMosquitoes Social InsectsSocial Insects Certain FliesCertain Flies ColeopteraColeoptera TicksTicks

Other methodsOther methods►Watching Watching

individualsindividuals►CamerasCameras►Examining Examining

crop/fecal crop/fecal contentscontents

►Stable Stable isotopesisotopes

Proper Curatorial TechniquesProper Curatorial Techniques

►Specimen Handling Specimen Handling and Preparationand Preparation

►Specimen StorageSpecimen Storage►Specimen Specimen

IdentificationIdentification

Specimen HandlingSpecimen Handling►Field preservationField preservation

FreezingFreezing Ethyl Alcohol (70%+)Ethyl Alcohol (70%+)

►95% for Molecular work95% for Molecular work

Ethyl AcetateEthyl Acetate Ethylene GlycolEthylene Glycol

►Useful for pitfall and Useful for pitfall and

similar trapssimilar traps

►Handle specimens carefullyHandle specimens carefully Even family level ID can require counting hairsEven family level ID can require counting hairs If breakage occurs, keep pieces with specimenIf breakage occurs, keep pieces with specimen

Specimen PreparationSpecimen Preparation

►Vouchers should be deposited in a Vouchers should be deposited in a entomological collection as a permanent recordentomological collection as a permanent record

►Each collecting event must be labeledEach collecting event must be labeled Location (both written and GPS coordinates), date, Location (both written and GPS coordinates), date,

collecting method, brief habitat description, and collecting method, brief habitat description, and collector should all be included on labelcollector should all be included on label

ARGENTINA: Jujuy,P.N. Calilegua, Arroyo 3 Cruces, 1110m, 23°41.629’S64°52.070'W14.i.2008 TACatanach Hg vaporlight, grassland TAC2008/040

StorageStorage

►Insects typically either stored dry, or in ethyl Insects typically either stored dry, or in ethyl alcoholalcohol If stored dry, low humidity and temperature will help If stored dry, low humidity and temperature will help

with preservation and dermestid beetle with preservation and dermestid beetle

controlcontrol If in ethyl alcohol If in ethyl alcohol

use 70%+ and use 70%+ and

check frequently check frequently

for evaporationfor evaporation

Specimen IdentificationSpecimen Identification

►What level of ID is What level of ID is

necessary to answer necessary to answer

the question?the question?►Species level is often Species level is often

not feasiblenot feasible►Be aware that one hour of collecting translates Be aware that one hour of collecting translates

into days of lab processinginto days of lab processing

SUMMARYSUMMARY► Invertebrate sampling requires knowledge of Invertebrate sampling requires knowledge of

invertebrate natural history and how it relates to invertebrate natural history and how it relates to the study question or wildlife species of interestthe study question or wildlife species of interest

► Collecting techniques are varied and often specific Collecting techniques are varied and often specific to habitats and target taxato habitats and target taxa

► Specimen handling, storage, and identification are Specimen handling, storage, and identification are integral parts of invertebrate sampling and a plan integral parts of invertebrate sampling and a plan for vouchers must be in placefor vouchers must be in place