Researching Pelecinids – Part 6

Last year I chronicled my experience researching Pelecinus polyturator in Dr. Norman Johnson’s lab. This research journey included learning the biology and behavior of P. polyturator, photographing specimens, collecting in town using Malaise traps, extracting DNA and amplifying it using polymerase chain reaction (PCR), learning the importance of literature reviews, and trying to collect live adults at Zaleski State Forest. Take a look at my previous blog posts to know more about these topics and catch up on my research so far.

author using laptop

The author analyzes DNA sequences using the Sequencher software

Over the last six months I continued working on my research, and now I have several exciting updates to share. While I took a hiatus from the lab in autumn semester to focus on my academic coursework, the research process did not stop. The DNA we extracted was sent out to be  commercially sequenced. Once I returned in spring semester, it was a matter of assembling those sequences and performing phylogenetic analysis before we could start drawing conclusions.

The focus of our study was the sex ratio variation between northern and southern populations of P. polyturator. Using molecular techniques we amplified sequences of the cox1 gene, which can be used as a genetic barcode to differentiate species. Additionally, we amplified the ftsZ gene in Wolbachia, an intracellular symbiotic bacterium that can effect sex ratio in insects. We suspected that if different strains of Wolbachia were present in the different P. polyturator populations, this could be a contributor of the observed sex ratio variation.

The Wolbachia turned out to be nearly identical from every locality sampled. On the other hand, the cox1 gene varied greatly between the northern and southern populations, and even between different localities of the southern population. From this information we concluded that the Wolbachia strain was not a direct cause of the sex ratio variation. The differences in the cox1 gene, however, suggested that there may be speciation occurring between the northern and southern populations.

Doing the research and analyzing the results was only a part of the process. Science is a collaborative endeavor, and it is important for a scientist to be able to communicate the results and ideas to others in a clear and concise way.

On March 1, I had the opportunity to present my research at the CFAES Undergraduate Research Forum. This is an event where students within the CFAES (that stands for College of Food, Agriculture, and Environmental Sciences) can showcase their research to other students and faculty, as well as a panel of judges. This forum attracts a wide audience of people from many different scientific disciplines and backgrounds. It is a great opportunity to interact with people who may not be familiar with entomology or molecular genetics. At first I was nervous to talk about my research, but it ended up being surprisingly fun to answer people’s questions. I even had a female P. polyturator specimen to show visitors, courtesy of Dr. Luciana Musetti and the Triplehorn Insect Collection.

Designing and presenting the poster was a great experience for me. I quickly learned that designing a poster is much different from writing a traditional scientific paper. Both formats are separated into similar sections such as an introduction, methods, results, and conclusions. A poster, however, has space constraints and must be attractive to a general audience. Large blocks of text typical of papers are unattractive and intimidating on posters. Overall, readability is the most important trait of a good research poster. The font should be large and easy to read, and everything should be spatially organized in a logical manner.

author and research advisor with poster

The author and her research advisor, Dr. Norman Johnson, stand in front of the research poster at the CFAES Research Forum.

author explaining research

The author explains her research to entomologist Dr. Megan Meuti

Presenting my poster at this research forum was a great preparatory experience for the upcoming Denman Undergraduate Research Forum. Because most of the research within CFAES was focused on agriculture and food science, I gained experience speaking to people unfamiliar with the topics of my research. The Denman will feature an even more diverse array of students and faculty, from business to chemistry to art, so I will need to be prepared to explain my research to those completely unfamiliar with entomology or molecular work. I will also be revising my poster using suggestions from the judges of the CFAES forum.

If you would like to learn more about my research project, as well as the research of other hardworking undergraduates, stop by the Denman in the Archie Griffin Grand Ballroom of the Ohio Union on Tuesday, April 3. I will be displaying my poster from 3:00 pm to 5:00 pm, and I would love to see you there!


About the Author: Hannah McKenzie is an undergraduate entomology major at the Ohio State University. She currently works as a curatorial assiatnt at the Triplehorn Insect Collection and is greatly enjoying her undergraduate research project on Pelecinus wasps.

Researching Pelecinids – Part 5

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.

image of Pelecinus Cove

The author searching for Pelecinids at Pelecinus Cove, photo by Dr. Luciana Musetti

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.

image of gel electrophoresis

The author learning protocols for gel electrophoresis

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.

Researching Pelecinids – Part 4

image of author extracting DNA

The author learning DNA extraction protocols

Over the last several weeks, I have been hard at work with my research on Pelecinids. I continued to collect weekly samples from the Triplehorn Insect Collection’s malaise traps, and I began to practice keying various families and superfamilies of Hymenoptera. I also learned the protocols for DNA extraction, PCR, and gel electrophoresis from graduate student Huayan Chen.

Not every aspect of research, however, is an active endeavor taking place in a lab or in the field. Research also requires a considerable amount of time for reading, writing, planning, and patience.

I am now in the process of shaping my research into an honors project that will span multiple semesters rather than this summer alone. Honors research is a much more demanding ambition than a single semester of research, but it is also a very rewarding experience that will push me to delve deeper into my research topic. I plan to expand the scope of my current research on Pelecinus DNA by also looking for DNA from Wolbachia, a bacteria that can influence sexual differentiation in insects. Huayan and I have already found that Wolbachia is present in several of our wasp specimens. I am also interested in the possibility of geographical parthenogenesis in P. polyturator females.

My current focus is on composing an honors project proposal. The purpose of the proposal is to establish how I plan to conduct my research, what materials I will need, and what goals I aim to meet. The proposal also includes an abstract, which is vital for exhibiting my research to the scientific community, and a literature review, which is important for ensuring the quality and relevance of my project.

The literature review has proven to be the most challenging portion of the proposal. It involves finding and reading the research of others, then synthesizing the information into a concise review and citing the sources in a list of references. Because there is such a vast amount of previously conducted research available to read, picking out the relevant studies and piecing the information together can be a time-consuming process. While searching for material to read, it isn’t uncommon for me to feel a little overwhelmed.

Despite the challenge, the literature review is one of the most important components of any research project for many reasons. First, it prevents the unnecessary repetition of collecting and interpreting data that another study already collected and interpreted in an identical manner. Second, it provides helpful context for the researcher. By reading about work that others have done on Pelecinus, Wolbachia, and parthenogenesis in Hymenoptera, I will be better equipped to design a procedure that is effective and efficient, or modify that procedure should something not work. Third, I can interpret data from other studies in relation to my own research findings, and vice versa, leading to a more comprehensive understanding of my final results.

image of P. polyturator

P. polyturator female

Although summer semester is coming to a close, I still have several research-related plans before I head back to classes this autumn. I will collect fresh P. polyturator specimens from Zaleski State Forest this August, which is when adults are most prominent in Ohio. These specimens will then be used for DNA extraction, along with several frozen or mounted specimens already in the collection. We also received a generous donation of West Virginian and Canadian P. polyturator specimens, which will be very useful for sampling DNA from a wider range of localities. I will also continue collecting from the malaise traps, keying Hymenoptera families and superfamilies, and reading relevant materials on DNA barcoding.


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.