Unlike many brown, nocturnal and nondescript moths, this one is bright, boldly patterned and looks more like a roll of batik fabric than a moth – and it’s out and about during the daytime. The Ailanthus Webworm Moth only reaches about half an inch in length. Its bright colors advertise that it is distasteful to eat.
This insect’s range extends from southern Florida south to about Costa Rica; this region is where native Ailanthus Trees grow and they are the moth’s caterpillar’s host plants, where the caterpillars live communally in webs. When people introduced Ailanthus Trees to North America, they spread invasively – this insect soon had a suitable host plant occurring far north of where it lived before.
Adult moths drink nectar from a variety of flowers, often in open habitats, usually during the day. Ailanthus Webworm Moths in all life stages cannot survive cold Winters, so when it freezes, northern populations are wiped out. But each Spring, the moths start expanding their range northward again, starting from warm southern regions.
It’s always neat to come across one of these cool creatures when out hiking. I often see them in Cuyahoga Valley National Park, like these examples seen under the Route 82 Bridge.