The pupal stage is a complicated period of larval tissue breakdown and differentiation of the adult structures. Periods of inclement weather, such as winter, are often endured in the pupal stage. The adult stage does little feeding and does not grow but provides dispersal, selects an appropriate habitat to lay its eggs, and reproduces sexually. If the adult selects the correct site to lay its eggs, the slow-moving caterpillar will hatch near a good source of food. Metamorphosis is considered complete when a clear distinction exists between larval and adult stage, such as from tadpole to frog and from larva to pupa to adult.
Some animals undergo gradual, or incomplete, metamorphosis.
The young resemble adults. Their form gradually changes into an adult through a series of molts. They undergo no pupal stage and no destruction of immature tissues. Examples of such animals are lobsters and cockroaches. Many marine organisms, both invertebrates and fishes, begin life as minute planktonic larvae.