This blog was created to share the stories and experiences of undergraduate mentees and graduate & postdoctoral mentors that participate in the Fisheries & Wildlife Undergraduate Mentorship Program at Oregon State University.
By: Catie Boucher, undergraduate in the Department of Fisheries, Wildlife, and Conservation Sciences
See this curious black bear? Imagine it meandering through a forest, in search of its next snack. As the bear moves, small black beetles scurry across the forest floor. A nearby spider is busy at work, spinning a web amongst the tree roots. In a game reminiscent of Six Degrees of Kevin Bacon, each of these animals are separated by only two degrees of Bacon. Who is their Kevin Bacon- their connecting link? Carpenter ants!
Carpenter ants (scientific name: Camponotus spp.) are an important food source for many organisms, including bears, beetles, birds, and spiders. They also chew holes in decaying trees for their nests, speeding up the decomposition of woody debris. Life isn’t always rosy in the Pacific Northwest, however. Forests often face high levels of disturbance due to logging and fire. Since these disturbances do not occur across the entire landscape- one area may be logged while another may not be- areas are impacted differently. Disturbances also typically occur at different times. These spatial and temporal differences create what is known as a ‘disturbance gradient’. In my project, I am exploring how the diversity of Carpenter ant species changes as environmental factors like the recency of disturbance, elevation, and forest age change. Understanding how a small but mighty organism like Carpenter ants respond to disturbances can help forest managers better know what to expect from the ecosystem, which allows them to recognize atypical responses.
But how would you even study this? First, you have to pick a study area, like the H.J. Andrews Experimental Forest. Then you have to categorize the study area, to make sure you collect samples from a wide range of sites- it wouldn’t do us any good if all our samples come from areas that were recently disturbed! Then comes the grueling fieldwork needed to collect the 380 samples. Marie Tosa, my graduate student mentor, did all this leg work for her own Ph.D. project. I hopped on board for the next step: sorting and preparing the samples for DNA analysis.
Marie chose to use pitfall traps, which sit in the ground to collect unsuspecting ground-dwelling insects as they wander by. Unfortunately, this method gathers a lot of organic debris, such as dirt and leaves, which need to be separated from the insects. I dove into the literature to figure out the best way to accomplish this, then wrote a protocol we implemented in the lab. We added de-ionized (DI) water to the ethanol that the samples were stored in to create a difference in the solution’s density. This allowed the lighter components- typically insects- to float, making it easier to pick through each sample and transfer insects to test tubes.
Then, we let them dry, weighed the biomass of each sample (to help quantify how many insects were in each sample), and stored them in the freezer until we could begin DNA extraction. The grant I received from the FW mentorship program was vital in purchasing Proteinase K, a fancy enzyme that helps degrade cellular debris and separate the DNA for a cleaner extract. (Having a bunch of extra debris makes it harder to hone in on the information we do want.) We used several solutions and a centrifuge to facilitate this process, resulting in a colorful final product:
My project isn’t quite finished yet- we are waiting for the extracted DNA to be sequenced, which will tell us the base pairs (for example, ATGCATC) in the samples. Since the sequences of base pairs are unique to each species, we can use a computer to match our sequences to a database to determine what was in our sample. Once we get these results, it’s off to the great big world of data analysis. We’ll spend time making sure that any patterns we find are statistically significant- that they didn’t occur just by chance- as well as build some fun maps. My end goal is to publish a paper based on the findings from this independent project!
I’ve loved working with Marie. She has been a supportive and kind mentor who indulges my long philosophical conversations (when you spend so many hours in a lab sorting through insects together, you get creative with your conversation topics). One of my favorite takeaways has been the kindling of a passion to make science accessible to everyone. Before I got involved in research, it always seemed like such a black box to me, especially terms like ‘sample processing’ and ‘data analysis’. Sometimes it’s not glamorous by any means- I don’t know many people who would be excited to sort through endless bug samples! But it is tangible to me now.
These days, I’m working with another grad student on the foraging range of Atlantic puffins in the Gulf of Maine, working as an Academic Coach on campus, and organizing events for Rotaract, my civic service club. Next summer, I hope to go to Borneo (Malaysia) on a faculty-led trip before graduating, then serve in the PeaceCorps. Lots of exciting things in the future!
A big thank you to the Fisheries and Wildlife Mentorship Program for selecting me as a FWUMPRA award recipient and supporting my undergraduate research!