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neoteny (nēŏtˈənē), in biology, sexual maturity reached in the larval stage of some animals. Certain environmental conditions can inhibit the completion of metamorphosis; low temperature or lack of available iodine retard the action of the thyroid gland, the larval form may mature sexually, mate, and produce fertile eggs. If environmental conditions improve, neoteny is reversible; i.e., the larvae can complete metamorphosis and attain normal maturity. When neoteny occurs in some salamanders (see axolotl), they remain aquatic. In insects, reproduction in the larval stages is known as paedogenesis; it occurs in certain beetles and gall midges. In the midges, the daughter larvae produced within a mother larva consume the mother and escape; the process may continue for several generations.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



reproduction by larval invertebrates. Unfertilized egg cells develop in the larvae, giving rise to a new generation. Paedogenesis is a form of parthenogenesis. The phenomenon was discovered in 1862 by N. V. Vagner in dipterous insects of the genus Miastor of the family Cecidomyiidae. The term “paedogenesis” was proposed in 1865 by K. M. Baer.

In paedogenesis, the daughter larvae feed on the tissues of the maternal larva as endoparasites, rupturing their host’s cuticle and transferring to an independent existence. Sometimes, after several generations of parthenogenetic larvae, there appear larvae that undergo complete metamorphosis and yield adult males and females that reproduce sexually.

Paedogenesis is an adaptation that compensates for inadequate fertility of adult forms, which are resettled passively. Both viviparous and oviparous paedogenetic larvae are characteristic of beetles of the family Micromalthidae, which are distributed in North America. Paedogenesis is also known among a number of marine cladoceran crustaceans (for example, the genus Podon). The development of embryos of rediae in the sporocysts and rediae of the first generation in digenetic flukes is another example of paedogenesis.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.