On August 10, I traveled to Zaleski State Forest with Dr. Norman Johnson and Dr. Luciana Musetti to collect Pelecinus polyturator specimens for my research. The area we visited has come to be known as Pelecinus Cove due to the relative abundance of Pelecinus wasps in the area.
Upon arriving at Pelecinus Cove, I could clearly see why Pelecinids are attracted to the locality. Adult Phyllophaga beetles tend to lay their eggs in the soil near trees. Pelecinids then parasitize the larvae that hatch from these eggs. However, females are not able to navigate their abdomen through the soil to oviposit if the ground is covered in grass or other dense vegetation. Therefore, the ideal location for a Pelecinus wasp would be a wooded area with mostly open ground. Pelecinus Cove definitely fits that description.
Equipped with insect nets and killing jars, we trekked through tall weeds and swarms of mosquitoes in search of the large parasitoids. Several minutes into our expedition, we noticed that not many insects were present other than a few moths and a lot of mosquitoes. We used our nets and feet to stir up the weeds in hopes of also stirring up resting Pelecinids. Unfortunately, even after an hour and a half of searching, there were no Pelecinids to be found.
Although the location itself was ideal, we speculate that other conditions were not. Ohio received a lot of rain in the weeks prior to our collecting trip, and the ground was very damp. This may have flooded out some of the Phyllophaga grubs or deterred the Pelecinus females from ovipositing. The number of grubs available to parasitize is a major limiting factor of how many Pelecinus females successfully reproduce, so if fewer Phyllophaga grubs were accessible due to damp soil, then fewer Pelecinids would be expected to stay in the area. The weather was also very cool, humid, and overcast. A little more sunshine and warmth may have enticed the Pelecinids, as well as other insects, to come out of hiding.
Despite the disappointing outcome of the collecting trip, fresh specimens are not completely unavailable. Prior to the collecting trip, I found a P. polyturator female in one of the Malaise trap samples. This exciting find also suggests that there are more wasps in the area that could be collected, so I am keeping my hopes up for more fresh specimens in the future.
Due to my autumn class schedule that begins next week, today is my last day working and researching at the Triplehorn Insect Collection for the summer. Looking back, I realize just how much I learned over the summer through my research experiences, including the value of DNA barcoding, how to extract DNA and amplify genes, how to collect from a Malaise trap, how to photograph large insects, and the fascinating behaviors of P. polyturator.
Although I won’t be participating in active, ongoing research this autumn, that doesn’t mean there won’t be more opportunity for learning and progress. I still plan to revisit my research regularly, read more about Wolbachia, continue editing my research proposal for the Honors project, and learn how to trim and read DNA sequences. When I return to my regular research schedule (hopefully in the spring), I will be well-prepared to continue where I left off. Thank you for following my research journey this far, and I hope that everyone reading has developed a new appreciation for the intriguing parasitoids of the genus Pelecinus.
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.