Pupa
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Image:Chrysalis5504.JPG Image:Pupation - Inachis io.jpg
A pupa (plural: pupae or pupas) is the life stage of some insects undergoing transformation. The pupal stage only occurs in holometabolic insects, those that undergo a complete metamorphosis such as butterflies and moths (Lepidoptera), beetles (Coleoptera), flies (Diptera) and bees, wasps and ants (Hymenoptera). The pupal stage follows the larval stage and precedes adulthood (imago). Pupae are sometimes sessile and have a hard protective coating. During the time of pupation, the adult structures of the insect are formed whilst the larval structures are broken down.
The chrysalis (plural "chrysalids") of a butterfly is an example of a pupa: because chrysalids are often showy and are formed in the open they are the most familiar examples. Most butterfly pupae are attached to a surface by a Velcro-like arrangement of a silken pad spun by the caterpillar and a set of hooks (cremaster) at the tip of the pupal abdomen. Moth pupae are usually dark in color and are usually formed in underground cells, loose in the soil, or in a silken cocoon spun by the caterpillar, sometimes suspended from a twig or concealed in the leaf litter. Insects emerge (eclose) from the pupa by splitting the pupal case, and the whole process of pupation is controlled by the insect's hormones. Those moths that pupate in a cocoon must escape from it, and they do this either by the pupa cutting its way out, or by secreting fluids that soften the cocoon.
Pupation may be brief, perhaps 2 weeks as in monarch butterflies, or the pupa may enter dormancy for the entire winter, or in the tropics for many months, until the appropriate season for the adult insect returns.
See also
Further reading
- For moth and butterfly pupae, see Malcolm J. Scoble. The Lepidoptera: form, function and diversity. Oxford: Oxford University Press. 1992.
- For pupae of other insect orders, see any text in entomology, for example a recent edition of Donald J. Borror, Dwight M. DeLong and Charles A. Triplehorn. An introduction to the study of insects. New York: Holt, Rinehart & Winston.be:Лялечка
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