It appears that many caterpillars within Acronicta are mimics of other caterpillars. These relationships have yet to be investigated beyond comparing superficial resemblances. This is something I hope to tackle with my own research.
For now I’m still raising some caterpillars for general life history data, waiting for them to pupate so I can get on with my life and have a little break from cleaning frass until the spring.
One species in my care is Acronicta impleta. It is supposed that this species mimics caterpillars in the family Lymantriidae. They have very similar tufts and coloration. Here is A. impleta
trying to look a lot like a Dasychira species
(image from BugGuide)
Many lymantriid caterpillars sting, so they would be a good group to mimic. Just look at all those nasty spines and tufts. A. impleta also has some other color variations, including a predominantly orange morph.
According to my advisor, A. impleta is most likely a harmless Batesian mimic. But today, while cleaning their containers, one brushed against my hand. It stung a little bit.
So being curious, I rubbed it against the back of my hand. AHHHHH!!!!
My skin turned red, I started getting little white spots around the sting site, and the reaction spread across the rest of my hand. It all had a low burning sensation, and lasted for about an hour (even after applying benadryl cream)
I asked my advisor and some fellow students to experiment on themselves, and while they happily obliged, none of them reacted. Perhaps I am just extra sensitive to this species or the physical hairs themselves? Or is there something chemical going on here? I would love to test this! Perhaps it is Mullerian mimicry and not Batesian if the A. impleta are themselves protected?
That was my excitement for the day.