Hypermetamorphosis

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Hypermetamorphosis is a term used in entomology and also in psychology. In entomology it refers to class of variants of holometabolism, that is to say, complete insect metamorphosis, but where some larval instars are distinct from each other. In psychology it refers to a psychological condition affecting reaction to visual stimuli.

Hypermetamorphosis in entomology[edit]

Hypermetamorphosis is a class of variants of holometabolism. In hypermetamorphosis some larval instars are distinct from each other. As a rule the first instar is a planidium. The form of planidium that occurs in the beetle family Meloidae is called a triungulin. The planidial instar is specialised for active mobility and is equipped to seek out the prey or host on which subsequent instars are to feed. In typical examples the first-instar larval morphology is campodeiform (elongated, flattened, and active, more or less resembling the morphology of Campodea) and in this form it does not feed. On locating its host it undergoes ecdysis, changing its skin and adopting a scarabaeiform (grublike) or vermiform (maggotlike) morphology.

As a rule the subsequent instars are of more or less constant form and not highly mobile, being specialised for feeding and growth until the final larval instar metamorphoses into the pupal form.[1]

Various forms of Hypermetamorphosis[edit]

Triungulin on a butterfly

Hypermetamorphosis usually occurs as an adaptation of the ontogeny of certain parasitoid insects, notably:

Technically the subimago of the Ephemeroptera might be described as a stage in a form of hypermetamorphosis, but that is not common practice.[2]

Examples of hypermetamorphosis in any given insect order are analogous and not homologous to those in any other order; for example hypermetamorphosis in the Acroceridae was not derived from the Strepsiptera, much less the Ephemeroptera.

Use in psychology[edit]

Hypermetamorphosis can also refer to a mammalian/primate psychological condition where there is excessive and indiscriminate reaction to visual stimulus. It is a symptom of Kluver-Bucy syndrome.[3]

References[edit]

  1. ^ Triplehorn, Charles (2005). Borror and Delong's Introduction to the Study of Insects. Peter Marshall. [page needed]
  2. ^ Richards, O. W.; Davies, R.G. (1977). Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development Volume 2: Classification and Biology. Berlin: Springer. ISBN 0-412-61390-5. [page needed]
  3. ^ Danek, A. (2007). "'Hypermetamorphosis': Eine Hinterlassenschaft des Breslauer Psychiaters Heinrich Neumann" ['Hypermetamorphosis': Heinrich Neumann's (1814–1884) legacy]. Der Nervenarzt (in German) 78 (3): 342–6. doi:10.1007/s00115-006-2171-2. PMID 17119892.