A misconception that I often hear regarding research is that it only takes place inside a laboratory. Although procedures such as PCR and DNA barcoding do take place inside the lab, there is also an in-the-field component that is vital to producing quality molecular research. In order to analyze the DNA of specimens, it is first necessary to collect those specimens. While I research pelecinids in the molecular lab, I will simultaneously learn about the process an insect collection goes through to collect, curate, and document new specimens that can then be made available for research.
One of the most effective means for collecting large quantities of insects in a short amount of time is the malaise trap. These large traps consist of a black mesh base and a white mesh tent. At the peak of the tent is an empty plastic bottle attached to a second bottle full of ethanol. Insects flying close to the ground become caught in the mesh and instinctively climb upward to escape, leading them into the empty jar. The ethanol vapors then knock out the insects and cause them to fall into the ethanol bottle (Vogel, 2017). Not only does the ethanol preserve the specimens, it also makes collection very simple. All one must do is detach the bottle of ethanol and empty it into a storage container such as a Whirl-Pak, then refill the bottle with fresh ethanol and reattach it for further trapping.
The Triplehorn Insect Collection sets up three Malaise traps during the warmer months, one near the Carmack parking lots and two at Waterman Farm. Each trap is set up in a different environment, so each trap collects a different variety of insects. For example, the Carmack trap is located near a pond and collects damselflies, whereas the Waterman Farm traps do not typically collect damselflies because they are located in dryer areas.
Although the traps are mostly intended for flying insects, other organisms such as spiders and ants often climb up the mesh and meet a similar fate. Pelecinid wasps will occasionally find their way into the traps, but it is not a very common occurrence. I will have the opportunity to collect from more Pelecinus-rich habitats later this summer.
I learned how to collect from these malaise traps from Huayan Chen, one of the graduate entomology students conducting research at the collection. In addition to learning how to empty and refill the ethanol bottles, I also learned that I need to cut back the weeds that grow around the traps and how to tie the knot that secures the bottles (a feat which took an embarrassingly excessive number of attempts for me to master). As part of my research experience, it is now my responsibility to collect the specimens from each trap once every week for the next several weeks. Each sample, which must be labelled with the collection date and locality, then gets stored in one of the collection’s freezers.
These samples will eventually get sorted into separate vials for each insect Order. What happens next depends on the goals of the collection. Some vials may be stored in the freezer for future use. Others will be further sorted to Superfamily or Family. They can then be further identified, mounted into the collection and databased, or used in molecular work.
I will use the Hymenoptera from these samples to learn the process of adding specimens to the collection. My plan is to further sort some of these specimens by Superfamily or Family (or even genus!), mount and label them, and enter them into the HOL database. In addition to teaching me the full collection process, this will also provide me with a better understanding of Hymenopetera morphology and identification that will be invaluable for the rest of my research.
Vogel, Gretchen. (2017). Where have all the insects gone? Science, 356 (6338), 576-579.
About the Author: Hannah McKenzie is an undergraduate entomology major at the Ohio State University. She currently works at the Triplehorn Insect Collection and is participating in undergraduate research on Pelecinus wasps.