A pupa (from Latin “pupa,” meaning ‘doll’) is a life stage of holometabolous insects undergoing transformation from immature to mature stages. These insects progress through four stages: egg, larva, pupa, and imago. Hormones, particularly juvenile hormone, prothoracicotropic hormone, and ecdysone, regulate the pupal stage. The process of becoming a pupa is called pupation, and emerging from the pupal case is known as eclosion.
Pupae have varying names, such as chrysalis for butterflies and tumbler for mosquitoes, and may be enclosed in cocoons or nests. There are two types of pupae based on mandible presence:
Decticous (with articulated mandibles, e.g., in Neuroptera and Mecoptera)
Adecticous (without articulated mandibles, e.g., in Coleoptera and Diptera).
Pupae can also be classified based on appendage attachment:
Exarate: free appendages, commonly not in cocoons (e.g., some Lepidoptera and Hymenoptera).
Obtect: appendages closely attached to the body, usually in cocoons (e.g., most Lepidoptera).
Coarctate: enclosed in hardened cuticle (e.g., Cyclorrhapha of Dipterans).
