holometabolisme

Holometabolisme, also known as complete metamorphosis, is a developmental process observed in many insect groups such as beetles, butterflies, moths, flies, and wasps. The life cycle consists of four distinct stages: egg, larva, pupa, and adult (imago). Each stage has specialized morphology and physiology suited to different ecological functions and resource utilization.

In the egg stage, the organism lays fertilised ova that may be deposited on or within suitable substrates. The larval stage follows, during which the organism typically has an elongated, worm‑like body, large chewing or sucking mouthparts, and a high rate of growth. Larvae often feed on a different food source than adults, reducing intraspecific competition. After sufficient growth, the larva enters the pupal stage. The pupa is a largely inactive, often sessile form in which extensive internal reorganization occurs. During this phase, larval tissues are broken down and adult structures are built, a process orchestrated by hormonal changes, notably the allatotropin hormone and ecdysteroids.

The adult stage is characterised by the development of fully functional wings, reproductive organs, and specialized sensory systems. Adults typically disperse to mate and lay eggs, completing the cycle. Holometabolisme allows efficient exploitation of multiple ecological niches and is linked to the evolution of complex life histories and high species diversity.