On September 22 2012, I encountered this caterpillar eating another fuzzy insect part along the White Trail of the State Botanical Garden of Georgia in Athens, GA. While the munching was going on, a familiar bully of the bushes the ground beetle (Calleida punctata) came in. The beetle harassed and eventually forced the caterpillar away from the leaf. I desperately needed help in explaining the sequence of events happening in this video. Why was the ground beetle so interested in the fuzzy part?
But before that was this caterpillar eating another caterpillar? Some species accumulate toxins in their bodies as a defense against parasitoid wasps by eating other toxic species. Perhaps this is what was going on? Those fuzzy hair are most certainly not something to mess with…
Therefore, I asked some nature enthusiasts + experts in Discover Life. Firstly, this was NOT a cannibalistic behavior. The caterpillar was actually eating its own discarded skin. This is quite common among caterpillars. In this way, once they shed they can recycle the defensive chemicals. These defensive chemicals usually are metabolically rather costly to produce. The behavior is somewhat similar to mammals eating the placenta after the offspring is born.
The caterpillar is a member of Arctiidae which includes all the Tiger Moths and this was most probably the Virginian Tiger Moth (Spilosoma virginica).