I came across this tiny (1.5 cm long) but handsome caterpillar on my walk to Piney Point this morning. It was lying immobile in the trail, under a white oak. Wagner’s Caterpillars of Eastern North America (what a great book!) notes that these caterpillars “may be active very late in the season, sometimes dropping down with autumn rains and winds.” After photographing the animal, I placed it on an adjacent oak sapling.
Murphy, Lill and Epstein’s study in the Journal of the Lepidopterists’ Society has some interesting background information on these caterpillars. They belong to the Limacodidae family, the so-called “slug caterpillar moths,” a group named for their strange offspring. All the species in the family have caterpillars that look like gummy worms going through a punk adolescence. Studs and spiky hair adorn colorful pudgy bodies. They can deliver quite a sting, as I noted a few weeks ago in my post about the saddleback, a different species in this family.
Murphy et al. confirm Wagner’s statement about the lateness of the species. This species is one of the season’s last active caterpillars, and are “frequently found feeding on leaves in the midst of turning color in late October, right up until leaf drop.”
Once they have finished growing, the caterpillars find a safe nook, then make a cocoon in which they enter a state of suspended animation (known as “diapause” in the zoological world). In the spring they make a pupa within the winter cocoon, then transform into an adult moth.