Various Modes of Reproduction

Abstract

Diversity and abundance of insects is reflected in their diverse reproductive strategies, which improve their survivability in adverse environments. Insects can largely be considered as oviparous or viviparous. Viviparity assumes different forms, such as ovoviviparity, pesudoplacental, haemocoelous, and adenotrophic viviparity. In some instances polyembryony has been observed while others show paedogenesis. While most insects reproduce sexually, asexual or parthenogenetic reproduction is also observed. The latter can be facultative, obligate, and cyclic or sporadic. The sex produced as a result of parthenogenesis also differs and forms the basis for further classification, viz., arrhenotoky, thelytoky, and amphitoky or deuterotoky. It can also be apomictic or automictic. It is also likely that a single species may show multiple modes of reproduction. Hermaphroditism is also a peculiar mode of reproduction observed in some species of insects. Although modes of reproduction in insects have been extensively reviewed, growing literature in recent decades has underscored functional significance and evolutionary basis of diverse modes of reproduction in insects. Asexual reproduction also influences genotyping of insects. Sex determination can also be affected by inherited bacterial endosymbionts, via cytoplasmic incompatibility, male killing, feminization, and induction of parthenogenesis; thereby, modifying modes of reproduction in several groups of insects. This chapter is a holistic attempt to provide details about insects’ diverse modes of reproduction and their functional significance with suitable illustrations.