Search the Web with our sponsor, Overture. The Larval Stage of a Butterfly A caterpillar is the larval stage of butterflies and moths. The caterpillar hatches from a tiny egg and will eventually pupate and turn into an adult butterfly or moth. This larval stage usually lasts from two weeks to about a month. This is the main feeding stage of the butterfly.
Caterpillars eat almost constantly and grow very quickly, at an astonishing rate.
They usually eat only the plant that their mother carefully chose to lay their egg on. Only a few lepidoptera larva are carnivores. The larva of the Harvester Butterfly exclusively eats woolly aphids. After the molt, while the new skin is still soft, they swallow a lot of air, which expands their body. Then, when the cuticle hardens, they let the air out and have room for growth.