pupate

Pupate is the process by which a larva of a holometabolous insect enters the pupal stage, a life phase between the larval and adult forms. During pupation, the insect is typically non-feeding and often immobile as larval tissues are broken down and adult tissues form. Pupation marks a transition from larval growth to adult development.

The pupal phase is driven by hormonal changes, notably a decrease in juvenile hormone and an increase in ecdysone, which coordinate tissue breakdown and the growth of imaginal discs that will become the adult organs, wings, and reproductive structures. In many species, the bulk of metamorphosis occurs during this stage, and most larval organs do not persist in the adult.

Pupation can take different forms and occurs in various environments. In butterflies and moths, the pupal stage is commonly enclosed in a chrysalis or cocoon. Beetles typically form an obtect pupa, in which the body is compact and the appendages are held close to the body; some other insects produce loose or exarate pupae with visible appendages. Pupation may occur beneath soil, within plant tissue, inside wood, or, in aquatic species, in water. The duration of pupation varies widely, from days to weeks, and some species overwinter in the pupal stage.

Pupation is a key feature of complete metamorphosis and distinguishes holometabolous life cycles from incomplete metamorphosis, where young resemble smaller adults and do not have a pupal stage. Examples of groups that pupate include butterflies, moths, beetles, bees, wasps, and flies.