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Census of Terrestrial Arthropods

Using Pitfall Traps

Objectives
Track changes in relative abundance and species diversity of arthropods on your campus. Conduct this research on different areas of your campus (adjacent to parking lot, under shrubs, on the playground etc.) to see how arthropod communities are different in different microhabitats. Conduct this research at different times of the year to track seasonal changes in arthropods.

Timetable
How many trapping sessions you do each year is really up to you and your schedule. You could do it as often as once per month or as infrequently as twice per year.

Equipment Required
large plastic drinking cups with small holes punched in the bottom (for drainage)
medium size plastic funnel cups with the end of the funnel cut out
small plastic ramekin cups with small holes punched in the bottom
trowel
data sheets Download datasheet as a Word Document, Download datasheet as a PDF
clipboard and pencils
forceps
empty film cannisters or collecting jars
reference books
"Sharpie" or other permanent marker

Methods
1) Choose 3 or more areas on your campus where you can install traps. These areas should be away from foot traffic, sprinklers, or other major disturbances.

2) In each of your areas, install a series of 5 pitfall traps. Allow at least 10 inches between the traps. To install the traps, dig a hole in the ground that is big enough to hold one of the large plastic cups. Make sure that the lip of the cup is flush with the ground. Place the ramekin cup inside the large plastic cup and then place the funnel cup inside the ramekin. The arthropod will fall into the funnel and be trapped in the ramekin.

3) Leave the traps open for 4 consecutive days.

4) Check the traps and record the numbers of each group captured, using the most specific taxonomic grouping possible (Order, Family, Genus, Species). If you cannot identify the animal, place it in an empty cannister, label the canister with the trap site, and keep the specimen to be identified later using a taxonomic key or an entomologist from SGS-LTER. Release the individuals that you were able to identify.

5) You can remove the traps when you are not using them or you can nail a cover over them. We use a cover made of 1/4 inch particle board.

6) Identify unknown specimens and check data sheets for completeness.

We are happy to visit your school and assist you with any part of this project. Please contact Laurel Hartley.

Relationship to Studies at SGS-LTER
At SGS-LTER we use pitfall traps to monitor arthropods on the eastern plains of Colorado. We census arthropods in various habitat areas once a month from April through October. By censusing arthropods, we can answer questions such as 1) How do arthropod communities differ between habitat types (ex. shrubland area vs. grassland area)?
2) How does relative abundance and species diversity of arthropods change with the seasons?
3) Using long-term data, can we see any major trends in abundance or diversity of arthropod species?
4) Can we learn anything by making comparisons between our weather data and our arthropod data?
5) Arthropods are prey for small-mammals, so do changes in abundance of mammals correlate with changes in arthropod communities?