After mating, adult moths immediately die. Eggs later hatch into caterpillars that feed a month or two, reach maturity, then spin a cocoon in which they spend the winter. These silk cocoons vary enough in shape and color to be used as a tool to identify the species that made them. In the spring, when warm temperatures return, adults emerge from the cocoon and the cycle continues. A cecropia cocoon attached to twigs will stay in place until spring.
Warm weather triggers the evolution of a new moth.
Cocoons can also be used to identify each species since they differ in shape and color. Moths have a special place in the web of life. These insects are important pollinators of plants and their caterpillars are a primary food source for songbirds. As a general rule, moths fly by night and butterflies fly by day. Butterflies depend on their bright colors to tell birds they have eaten plant toxins and therefore taste bad.