Parthenogenesis in Hexapoda: a review. I. Entognatha and non-holometabolous insects
In hexapods, unlike most animals, development without fertilization is a very common phenomenon. They evolved a striking diversity of unisexual reproductive types that include a variety starting from spontaneous parthenogenesis in females to production of impaternate males with different variants in-between. Many reports about parthenogenetic species have accumulated over time. Here we present a review of various parthenogenetic hexapod groups with a particular focus on their chromosome systems and the ploidy level. We show that conclusions about the reproductive mode often lack of solid evidence and sometimes inefficiently demonstrate how parthenogenesis is maintained in corresponding groups. In this part of the review basal hexapods (Protura, Collembola, Diplura), primary wingless insect groups (Apterygota) and non-holometabolous insects are listed with references to a variety of their unisexual reproductive modes.