holometaboloosi

Holometaboloosi, also called holometaboly or complete metamorphosis, is an insect developmental pattern characterized by four life stages: egg, larva, pupa, and adult. In holometaboloosi development, the larva typically differs markedly from the adult in morphology, ecology, and diet. The larva is often worm- or grub-like and specialized for feeding and growth; the pupa is a non-feeding, transformative stage during which tissues and organs are reorganized into the adult form; the adult is typically focused on dispersal and reproduction. The transition between stages is regulated by hormonal changes, notably ecdysone and juvenile hormone.

Organisms that exhibit holometaboloosi include the vast majority of insects across several orders, most notably Lepidoptera (butterflies and moths), Diptera (flies), Coleoptera (beetles), and Hymenoptera (ants, bees, wasps). Some other groups also show complete metamorphosis, including Strepsiptera. The complete metamorphosis provides ecological advantages, including reduced competition between immature and adult life stages, exploitation of different food resources, and greater diversification.

The term derives from the Greek holos, meaning whole, and metabole, meaning change. The holometaboloosi developmental mode likely evolved during the late Paleozoic to early Mesozoic, with fossil evidence in Permian and Triassic deposits, and it has since become the dominant developmental strategy among insects.