First published in the OSU Biomuseum blog on 2015-08-31; minor corrections.
Collecting insects is one of the many activities of the staff and volunteers at the Triplehorn Insect Collection. Each time we go out in the field and collect we create a tiny snapshot of the insect fauna of that specific place and date. It’s far from complete, but adds to our knowledge nonetheless. We do not need to go far to find insects that no one has ever studied before. Even in our own backyard, next door to the Museum of Biological Diversity, we find new or rare insect species and discover new facts about known species.
One of the methods we frequently use to collect small flying insects is the pan trap – a bowl with water and a drop of clear, unscented liquid soap. The soap breaks the surface tension of the water and makes the insects sink. The color yellow (bright yellow!) attracts many insects, including the parasitic wasps that several of us in the collection study. Our yellow pan traps, (or YPTs for short) are simple plastic party bowls. For best results we leave the YPTs out in the field for about 24 hours. After that we remove the catch, and start the cycle again: fill the YPTs with water, add soap, leave for 24 hours, remove catch. We usually set up 25-50 YPTs in one spot and that’s one sample.
There are a couple of variations on how to empty the traps: scooping the specimens with a fine fish net, or pouring the content of the trap through the net. Either way the specimens get separated from the soapy water, and then are carefully washed with clean water to remove all the soap residue. Once washed, the specimens are preserved in 95% ethanol and placed in a freezer. That slows the degradation of their DNA and allows for molecular level studies. Later, we sort the specimens into groups (beetles, wasps, leafhoppers, etc.) and start the long process of specimen preparation for study. The YPTs are washed and saved for the next collecting season.
About the Author: Dr. Luciana Musetti is the Curator of the Triplehorn Insect Collection at Ohio State University. All photos are courtesy of the author, except for the one of Hans Clebsch.