INVERTEBRATE SAMPLING METHODS INVERTEBRATE SAMPLING METHODS Therese A. Catanach Program in Ecology, Evolution, and Conservation 1816 South Oak Street, MC 652 Champaign, IL 61820

Bugs in a Wildlife Class? ► Invertebrates provide food for many wildlife and game species ► Perform many ecosystem services ► Disease vectors ► Indicators of ecosystem health

Deciding the Scope of the Question ► What is the scope of your question?  General questions ► Habitat survey: what insects live here? ► Impact of management  Species related questions ► Feeding surveys ► Prey availability survey

Invertebrate Natural History ► Invertebrate natural history is important  Presence does not equal availability ► Size ► Activity level ► Habitat preferences  Many invertebrates are toxic or mimic those that are

Considerations for Invertebrate Sampling ► Some insects more likely to be caught in a certain trap than others  Habitats frequented  Activity periods  Attractants used for trapping

Sweep Nets ► Collect invertebrates in vegetation or flying ► Difficult in thick vegetation or when vegetation has thorns/spines ► Can be general or targeted  Hymenoptera  Diptera  Hemiptera  Lepidoptera  Orthoptera  Coleoptera ► Not good for ground dwelling invertebrates

Malaise Traps ► Passive trap set up along flyways ► Placement determinescatch  Hymenoptera  Diptera  Some Hemiptera  Some Coleoptera

Flight Intercept Traps ► Similar to Malaise Traps ► Targets insects that fall rather than climb when barriers encountered  Beetles  Orthoptera

Pan Traps ► Different colors attract different insects ► Passive Collecting  Diptera  Hymenoptera  Hemiptera

Sticky Traps ► Standardized trapping effort if placed similarly ► Positioning or damage can make identification challenging ► Targets  Diptera  Hymenoptera  Hemiptera  Coleoptera

Vacuum Devices ► Ideal for collecting in grasses ► Separate invertebrates from litter using emergence traps or by hand ► Targets  Hemiptera  Hymenoptera  Diptera

Light Traps ► Species must be attracted to light ► Different wavelengths of light attract different taxa ► Targets  Lepidoptera  Coleoptera  Hemiptera

Aquatic Net ► Many methods  Dragging through sediment  Disturbing rocks and other shelters ► Targets  Immatures of many orders  Aquatic invertebrates

Beat Sheets ► Ideal for vegetation that’s difficult to sweep  Coleoptera  Hemiptera  Spiders

Attractant Traps ► Uses attractants (C02, pheromones, fermenting fruits, etc.) ► Targets  Mosquitoes  Social Insects  Certain Flies  Coleoptera  Ticks

Other methods ► Watching individuals ► Cameras ► Examining crop/fecal contents ► Stable isotopes

Proper Curatorial Techniques ► Specimen Handling and Preparation ► Specimen Storage ► Specimen Identification

Specimen Handling ► Field preservation  Freezing  Ethyl Alcohol (70%+) ► 95% for Molecular work  Ethyl Acetate  Ethylene Glycol ► Useful for pitfall and similar traps ► Handle specimens carefully  Even family level ID can require counting hairs  If breakage occurs, keep pieces with specimen

Specimen Preparation ► Vouchers should be deposited in a entomological collection as a permanent record ► Each collecting event must be labeled  Location (both written and GPS coordinates), date, collecting method, brief habitat description, and collector should all be included on label ARGENTINA: Jujuy,P.N. Calilegua, Arroyo 3 Cruces, 1110m, 23°41.629’S64°52.070'W 14.i.2008 TACatanach Hg vapor light, grassland TAC2008/040

Storage ► Insects typically either stored dry, or in ethyl alcohol  If stored dry, low humidity and temperature will help with preservation and dermestid beetle control  If in ethyl alcohol use 70%+ and check frequently for evaporation

Specimen Identification ► What level of ID is necessary to answer the question? ► Species level is often not feasible ► Be aware that one hour of collecting translates into days of lab processing

SUMMARY ► Invertebrate sampling requires knowledge of invertebrate natural history and how it relates to the study question or wildlife species of interest ► Collecting techniques are varied and often specific to habitats and target taxa ► Specimen handling, storage, and identification are integral parts of invertebrate sampling and a plan for vouchers must be in place