Pupa
The transformative pupal stage bridges larva and adult insect.
A pupa (from Latin pupa 'doll'; pl.: pupae) is the life stage of insects from the Holometabola clade undergoing metamorphosis between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages thereof being egg, larva, pupa and imago (adult). The pupal stage follows the larval stage, or in some cases a prepupal stage, and precedes adulthood in insects with complete metamorphosis.
- Type
- Life stage of holometabolous insects
- Key Hormones
- Juvenile hormone, prothoracicotropic hormone, ecdysone
- Duration
- Weeks, months, or years depending on species and temperature
- Common Names
- Chrysalis (butterflies), tumbler (mosquitoes)
- Primary Function
- Formation of adult structures from imaginal discs
- Defense Mechanisms
- Cocoons, camouflage, underground placement, chemical secretions
Lore & Background
The pupal stage is a non-feeding, usually sessile stage, though some pupae such as those of mosquitoes are highly active. During this stage, adult structures are formed while larval structures are broken down, growing from imaginal discs. Contrary to popular belief, larvae do not completely liquify inside the cocoon. The processes of entering and completing the pupal stage are controlled by hormones, especially juvenile hormone, prothoracicotropic hormone, and ecdysone.
Reader's Guide
The pupal stage is a critical period in the life cycle of holometabolous insects, representing the transition from larva to adult. Its duration can vary dramatically—from weeks to years—depending on temperature and species, and it may involve dormancy or diapause to align emergence with favorable seasons. Pupae are typically immobile and defenseless, leading to diverse protective strategies such as cocoons, camouflage, underground placement, or chemical defenses. The stage is also notable for specialized reproductive strategies like pupal mating in some Lepidoptera, where males mate with emerging females. Understanding pupal biology has practical importance in agriculture, pest control, and sericulture, as the silk moth's cocoon is the source of commercial silk. The study of eclosion timing, regulated by circadian clocks, also contributes to chronobiology.
Did You Know?
- The act of becoming a pupa is called pupation, and emerging from the pupal case is called eclosion or emergence.
- Pupae of butterflies are called chrysalides, derived from the Ancient Greek word for gold.
- Some pupae, such as those of fleas, have emergence triggered by vibrations indicating a potential host.
- In social hymenopterans, pupae are protected by adult members of the hive.
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