paurometabolism

Paurometabolism is a form of metamorphosis in insects characterized by incomplete metamorphosis with gradual development through multiple molts, a lack of a pupal stage, and immature forms (nymphs) that resemble the adults in body plan. Nymphs are typically wingless or have only small wing buds, and they occupy the same environments and exploit similar food sources as the adults. Wings, when they appear, develop externally as wing pads during the later instars and are fully formed only after the final molt.

During paurometabolic development, successive molts increase size and add adult features step by step. Because nymphs resemble adults, paurometabolic insects are often perceived as miniature versions of the adults, differing mainly in size and the presence or extent of wing development.

Taxonomic distribution of paurometabolism includes several groups traditionally treated as insects with incomplete metamorphosis. Notably, cockroaches (Blattodea) and termites (Isoptera) are commonly cited as having paurometabolic development in many classifications, as are other polyneopteran lineages in some accounts. The pattern is contrasted with holometabolism, in which development includes a larval stage that is morphologically distinct from the adult and a pupal stage between them.

Terminology can vary by author. In many classifications paurometabolism is considered a subset of hemimetabolism (incomplete metamorphosis), often distinguished by the notable similarity between nymphs and adults and the gradual acquisition of wings, which only fully develop in the final molt.