The Electrophysiology of Dragonflies
Hi everyone, I’m Jaimie. I just graduated from Boston’s Northeastern University in Behavioral Neuroscience. My academic background is in biology, but I picked up some engineering and coding skills through previous lab research. Originally I’m from the Chicago area, so I’m pretty familiar with the Midwest atmosphere, though I had never been to Ann Arbor before this internship. I brought my ferret, Taz, with me too. I’m really enjoying working at Backyard Brains so far; my project has been a lot of fun, and my coworkers are great to hang out with! I haven’t done much exploring of the city yet, although I went with Joud, Nathan, and Ilya to the University of Michigan Museum of Art. There were some really cool performance pieces there, so if you’re in the area, you should check it out!
I am working on a continuation of Patricia Aguilar’s dragonfly investigation from last summer. Dragonflies have very complex flight patterns, as each wing can move individually (rather than as a pair with its contralateral counterpart). Further, they are able to intercept their prey mid-flight with 95% accuracy. This leads to some questions about how their behavior is possible. Essentially, dragonflies’ neurons in their eyes connect to their wings in a reflex circuit, rather than processing the visual information first. This allows them to make sharp turning maneuvers very quickly in order to follow and catch their prey. These important neurons, 8 on each side, lie in tracts along the neck of the dragonfly. They are called target-selective descending neurons (TSDNs). My primary aim is to record from these neurons to identify the visual receptive fields of each one, similar to the study performed by Paloma Gonzalez-Bellido et al, here. Right now, I am in the process of weighing the pros and cons of various visual stimuli and experimental methods done by Robert Olberg (an author on the linked paper), though I will likely be doing something similar to Patricia’s laser rig. Stay tuned for updates on this.
Last Thursday, I spent the day in the arboretum trying to catch dragonflies. I learned quite a few lessons about what to wear (dress to prevent bites, not stay cool!) and how to find them. Dragonflies eat mosquitos, midges, and almost any other smaller insect they can find. Mosquitos lay their eggs in still water, so dragonflies tend to be found near their food sources. The banks of a river or a marsh are ideal places to look. I was using a net and alternated between swinging the net like a bat (Swing method) and going from above to trap it to the ground (Pancake method). My end result was a catch of 3 damselflies and 1 unknown insect (possibly a wasp?). Note that the pictures are after anesthetizing the insects in the refrigerator overnight. Damselflies are tricky in that they look and act similarly to dragonflies, but upon closer inspection, there are slight differences; they have thinner bodies compared to dragonflies, and instead of displaying their wings when perched at rest, they keep them together. I recognized that these were damselflies before catching them, and though I can’t technically use the data I get from these bugs, I can practice recording from their neurons and improve on my surgery setup. I’ll be sure to show the final setup and materials I used when I have a successful recording.
Quick Update: I tested the recording rig on a Damselfly! Now to catch some Dragonflies…
I’d love to hear from you if you have any suggestions or inquiries. Thanks for reading!