Guest Post by Lily Durkee, 2023-2024 Sustainability Leadership Fellow, and Ph.D. Candidate in the Department of Agricultural Biology and Graduate Degree Program in Ecology at Colorado State University
My first season of field work crammed the emotional roller coaster of three years of grad school into a single summer. There was a period of what am I supposed to be doing? followed quickly by how am I supposed to do all of that? followed by putting my head down and doing all of that in only four months.
Here is a day of “that.”
I arrive at Rabbit Ears Campground around one in the morning, so I don’t know what to expect in the daylight. I awake to a swarm of mosquitoes lining the outside of my tent at an alarming density. I carefully put on my field clothes, making sure to tuck in everything – my pants into my socks, my shirt into my pants – and then I run to the car and apply DEET to every inch of my body.
I’m not collecting mosquitoes, right? I think.
I grab my mesh net, my fanny pack full of field supplies, and I set off into the adjacent meadow. The morning dew is beginning to dry, and the sun peeking through the clouds illuminates a lush field of wildflowers. I look at my watch – 9am. Perfect timing, I think.
I walk around slowly at first, swatting mosquitoes from under my hat, enjoying the distant views of the nearby Flattop Mountains. Then, out of the corner of my eye, I see a flash of yellow. Game time.
Gripping my net tightly, my eyes focus in on the culprit: a rapidly flapping, pale yellow butterfly, its wings each about the size of a quarter, flying quickly and erratically about 100 feet away from me. I take off at a sprint, my net held high, as my eyes dart back and forth, following the path of the butterfly. As I close in, the breeze picks up momentarily, sweeping the individual far across the field, out of sight.
I’ll get the next one, I think, coming to a stop and panting.
For the last chapter of my PhD dissertation in ecology, I wanted to study a wild insect population. My first two projects used lab-raised populations of beetles, so I was excited to get out in the field. I worked with several entomologists including my advisor, Dr. Ruth Hufbauer, and the late lepidopterist, Dr. Paul Opler, to develop a study that would examine adaptation to elevation in the Rocky Mountain subspecies of the clouded sulfur butterfly (Colias philodice eriphyle), which is native to Colorado and lives along an elevation gradient between 5,000 and 9,000ft in elevation1. I planned to collect butterflies at “low” elevation sites across the Front Range and Western Slope to compare to “high” elevation sites in the Rocky Mountains. Then, I planned to use genomic sequencing to identify patterns of adaptation between low and high elevation populations.
No one told me when I developed this study, however, that the clouded sulfur was the fastest butterfly in Colorado. Male clouded sulfurs conduct long, erratic, and swift flights in search of mates 2. The butterflies I see flying in the field, therefore, are mostly males, and their successful reproduction depends on their ability to search for and find a mate without getting eaten by a predator (or caught by me). It makes sense that they are so speedy!
I see another flash of yellow and I’m off running again. After about 500 feet, I see the butterfly land on a small clover plant – a miracle. I take three more large steps then slam my net down on top of the plant, trapping it. I make sure the net opening stays in contact with the ground as I kneel and grab the mesh, making sure the butterfly is at the bottom of the net. I then carefully open the mesh, keeping the mouth pointed down (butterflies will always fly up, which was the first thing Dr. Opler taught me), and grab a small glassine envelope from my pack. I carefully guide the butterfly inside, folding its wings gently, close the envelope, and write an ID on the outside. Then, I place the envelope in an Altoids box – another trick I learned from Dr. Opler.
The day continues in a similar fashion. Every few minutes, a clouded sulfur flies, and I sprint after it. About 30% of the time, I succeed. After about five hours, I’ve netted the 20th butterfly, my goal for the day. I breathe a sigh of relief and walk back to the car, my feet and lungs exhausted. I place the Altoids box into a cooler to keep the butterflies from overheating and then drive to the nearby town of Steamboat for a well-deserved meal and soak in the local hot springs.
I can’t wait to do it all again tomorrow.
References
1) Ellers, J., & Boggs, C. L. (2004). Evolutionary genetics of dorsal wing colour in Colias butterflies. Journal of Evolutionary Biology, 17(4), 752–758. https://doi.org/10.1111/j.1420-9101.2004.00736.x
2) Kingsolver, J. G. (1983). Ecological significance of flight activity in Colias butterflies: implications for reproductive strategy and population structure. Ecology, 64(3), 546–551. https://doi.org/10.2307/1939974