Pupae

Pupae are the life stage between the larva and the adult in many insects that undergo complete metamorphosis. In this stage, growth stops, the insect is usually immobile, and tissues are reorganized to form the adult organs and structures. Pupation marks a transition from feeding larval life to reproductive adult life.

During the pupal stage, the insect typically remains encased in a protective covering. In butterflies and moths, this covering is a chrysalis; in beetles, the pupal case can be hardened and exposed or partly enclosed; in bees, wasps, and ants, the pupa may develop inside a cocoon or a wax cell. Inside the cover, larval tissues are broken down and rebuilt into wings, legs, antennae, and other adult features. Some pupae are unprotected exoskeletons that are fully enclosed, while others are free to move slightly or have visible appendages.

The duration of the pupal stage varies by species and is influenced by temperature, humidity, and day length. Some pupae overwinter or enter diapause as a seasonal adaptation to unfavorable conditions. Environmental cues often determine when development resumes and the adult emerges.

Pupation is characteristic of holometabolous insects, such as butterflies, moths, beetles, bees, wasps, and flies. By contrast, insects that undergo incomplete metamorphosis do not have a pupal stage; their young (nymphs) resemble small adults and grow through molts. The pupal stage thus serves as a developmental bridge between larval feeding and adult reproduction.