neoteny, 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.