Paedogenesis

Definition

Precocious sexual maturation in an organism that is still in a morphologically larval or juvenile stage, allowing reproduction before the adult body form is achieved. In paedogenesis, somatic development is truncated rather than retarded, distinguishing it from neoteny where juvenile traits are retained in a sexually mature adult.

Etymology

From Greek pais, paidos (child) + genesis (origin, production)

Example

In the gall midge Heteropeza pygmaea, paedogenesis allows the larva to produce eggs that develop parthenogenetically within the maternal larva's body, generating multiple generations of larvae without ever reaching the adult stage.

Synonyms

• progenesis

Related Terms

• Neoteny
• paedomorphosis
• Parthenogenesis
• larviparity
• viviparity
• heterochrony
• Metamorphosis

Usage Notes

Paedogenesis is distinguished from neoteny by the developmental fate of the soma: in paedogenesis, the larval body never transforms into an adult, whereas neoteny produces a sexually mature adult with juvenile morphology. The term is sometimes restricted to cases where the juvenile itself reproduces (as in some Cecidomyiidae and Chironomidae), while progenesis may be used more broadly for accelerated gonadal development. Paedogenesis should not be confused with paedomorphosis, the general retention of juvenile traits, which includes both paedogenesis and neoteny as distinct mechanisms.