So my “Live tweets” won’t be of much use for those people that have no idea what I am doing this summer. Currently, I am in the 2nd phase of my PhD research. Again, I am examining caterpillar eyespots - their ecology and evolution. These caterpillars with eyespots are generally thought to be snake-mimics – caterpillars that resemble snakes and are therefore protected from their bird predators that fear and avoid snakes. At least that's the idea, it has yet to be demonstrated and fully understood.
Last year I tracked the survival of artificial caterpillars with and without eyespots in the field. This project indicated that eyespots alone may not be sufficient to deter birds from attacking; however our experimental design did not include caterpillar behaviour which may play a critical role in deterring bird attacks. The next logical step is to determine how well these live caterpillars which naturally possess eyespots can deter attacking birds. I’m currently finishing the manuscript from that work, and I’ll provide more details about it later.
This summer’s goal is to generate a better understanding of the behaviours expressed by caterpillars with eyespots. Specifically, I’m interested in behaviours that might help the caterpillars survive an attack from a bird. If you watch the YouTube videos in my last post you can see some examples. Many caterpillars that have eyespots will also contort or flick their body when they are threatened. These behaviours may ‘startle’ attacking birds, and I suspect that they augment the fear response associated with the eyespots.
Overall, my project goals for this summer are:
1) Describe and measure the anti-predator behaviours of Papilio canadensis caterpillars associated with real and simulated attacks.
2) Determine the efficacy of ‘eyespot’ markings in deterring lethal bird attacks in conjunction with, and separated from, caterpillar behavioural responses.
As I mentioned, I am working primarily with Papilio genus (Swallowtail) caterpillars. I live in Ontario, Canada and the species here is Papilio canadensis. It is closely related to Papilio glaucus which distributed just to the south of us, and has a very similar ecology. I am currently out catching adult female Swallowtail caterpillars, bringing them into captivity, and then sleeving them over their host plant (Trembling Aspen) so lay eggs. These eggs will be reared to caterpillars that I can use to quantify behavioural responses to simulated and real attacks. I’ll post pictures and descriptions of this process in more detail later.