The bagworm moth (Psychidae) of the family Lepidoptera might be a pest for Botanists, but for Lepidopterists they are one of the rare architects of the animal world. As soon as the caterpillar of the bagworm moth hatches, it weaves a silk cocoon around itself, inside which it will live until it grows into an adult moth. To make its life as a larva safe and protected from predators, the caterpillar reinforces its silk cocoon with pieces of twigs, leaves and other plant matter. Depending on what debris is on hand when they are forming the cocoon, the resulting shelter might look like a bunch of twigs, or in exceptional cases, a tiny log house. These strcutures are called cases, and bagworm moths are also known as "case moths”.

The cocoon of the bagworm moth looks like a tiny log house. Photo credit: melvyn yeo/Flickr