The pain receptors on Marianne Tyndall’s arm found this impressively spiny caterpillar on some garden vegetation yesterday. The caterpillar is about two inches long. Its sting causes pain that feels like a combination of burning skin and tearing muscle. Pretty impressive. The pain is bad enough to cause some people to call a poison center, as reported here. Note that the paper in this link uses the old genus name, Sibine. The paper also relates events in Louisiana where people evidently have different attitudes to caterpillar attacks — in Sewanee, we suck up the pain, then carefully gather the caterpillar to bring it to fellow naturalists.
The stinging hairs deter predatory wasps and assassin bugs. Wasps learn to recognize the caterpillars and after a few inspections, leave them well alone.
The colorful caterpillar turns into a fuzzy brown moth.