Paedomorphosis in the family Phytoseiidae (Acari: Gamasina)

Abstract

The Phytoseiidae are characterized by idiosomal hypotrichy. The process of setal suppression that caused this hypotrichy has led to paedomorphosis due to the differential suppression of setae appearing in the later developmental stages of ancestral forms; hence there is a tendency for larval setation to persist into the adult stage of modern phytoseiids, with few setae being added in the later stages of ontogeny. Because setal suppression seems to have been accompanied by reductions in development time and body size, it is suggested that paedomorphosis in this group is of the type defined as sequential progenesis.