What’s wrong with the caterpillars? Why are pieces falling off of them?

If you’ve stopped by the youth services desk in the last two weeks or if you’re following us on Twitter, you may have noticed that the Garden Club is raising painted lady butterflies. Five of them have entered their chrysalis stage, but when they were still caterpillars, we were noticing fuzzy black bits at the bottom of their enclosure. Some patrons wondered if something was wrong.

As it turns out, the fuzzy black bits were totally normal. Caterpillars are continuously growing and their exoskeletons don’t grow with them, so they must molt. They shed their head capsules first, followed by the rest of their skin, and are usually very still when preparing for a molt. They’ll often eat their old exoskeleton. We were just seeing the leftover pieces.

For more information, check out Myriam Baran’s Butterflies of the World or Paul Smart’s Illustrated Encyclopedia of the Butterfly World, both of which are available here are the library.