The white walls of our office building and kennels tend to attract quite a few nocturnal insects, so I’m never surprised if I find a moth or a katydid when I go outside during the day. Earlier this summer I found this spiny oakworm moth (Anisota stigma) perched on one of the walls. She looked pretty beat up with several small pieces of wing missing, so I suspect she was nearing the end of her life. Even in her rough shape, though, she was still quite beautiful. It was also nearing the end of the usual flying time for these moths. These moths are usually on the wing between July and August around here and a little earlier (usually June and July) in the northern part of it’s range. It can be found from southern Ontario south along the east coast to Florida. The range extends as far west as Minnesota and Texas as well as into Mexico.

Even though this moth is very attractive with it’s combination of browns, oranges, blacks, and purples, it is the caterpillars that gives it it’s name. The caterpillars tend to be brownish or greenish and are covered in many black spines. The caterpillars have a voracious appetite for the leaves of various types of oak trees. When they first hatch out, the caterpillars feed in groups and one small group can completely defoliate a small oak tree. As they grow the groups tend to spread out, but still feed heavily. As cold weather approaches, they dig down into the leaf debris and pupate. They overwinter in that state and don’t emerge until the following year in late spring. Interestingly, the adult moths do not feed at all, which explains both their relatively short flying times and the amazing appetites of the larvae.