Molting |

Two of the four black eastern swallowtails were molting in the butterfly house, one of which was consuming its old skin.

The molting takes place because their skin does not grow as they consume more leaves from their host plant. So, to have enough room, the caterpillar first grows new skin underneath before it sheds its old skin. The new exoskeleton is first soft before hardening to protect the caterpillar. The caterpillars below are, I believe, in their third, or fourth instar.

There are three pairs of true legs of a caterpillar, as well as five “pro-legs” that function the same. Interesting fact, the true legs eventually turn into the butterfly’s legs and the pro-legs vanish during metamorphosis.

Another interesting fact: the caterpillar consists of strong jaws, which are connected to a digestive tube that has an opening for the caterpillar’s waste. It’s crazy to think that a caterpillar consumes twice its body weight in a day.