Progenesis

Progenesis is a mechanism in developmental biology that is associated with paedomorphosis. Progenesis refers to the attainment of sexual maturity by an organism still in its larval or juvenile stage and a secondary result of never experiencing later developmental stages. Organisms that are progenetic never achieve the adult form experienced by their evolutionary ancestors.

Mechanisms of progenesis
Progenesis is sometimes induced by environmental conditions that inhibit the completion of metamorphosis, such as low temperature or lack of available iodine leading to low thyroid gland activity. The larval form may mature sexually, mate, and produce fully viable offspring. If environmental conditions improve, this particular kind of progenesis can sometimes be reversed, with the larvae completing metamorphosis and attaining normal maturity.

Animal Kingdom
This biological state is found predominantly among certain amphibians but primarily among insects.

Paedogenesis
Progenetic organisms are capable of paedogenesis. This is the act of reproducing while in the larval form and occurs in the females of certain beetles, Strepsiptera, bagworms, and gall midges.