Parthenogenesis in Hexapoda: Entognatha and non-holometabolous insects

Abstract

In hexapods, unlike the majority of animals, development without fertilization is a common phenomenon. They evolved a striking diversity of unisexual reproductive types that include a variety of modes starting from spontaneous parthenogenesis in females to the 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 ploidy level. We show that conclusions about the reproductive mode often lack solid evidence and sometimes inefficiently demonstrate how parthenogenesis is maintained in corresponding groups. In this review, basal hexapods (Protura, Collembola, Diplura), primarily wingless insect groups (‘Apterygota’) and non‐holometabolous insects are listed with references to a variety of their unisexual reproductive modes.

Parthenogenesis in Hexapoda: holometabolous insects

“…This study is a second part of a review of parthenogenesis occurring in Hexapoda (=insects in a broad sense). Entognatha and non‐holometabolous insects were reviewed in our previous work (Vershinina & Kuznetsova, ), and this study therefore deals with Holometabola, a monophyletic group comprising the overwhelming majority of insect species (Beutel et al., ; Peters et al., ; see also Misof et al., ). Holometabola comprise 11 orders, including the megadiverse ones, that is, Coleoptera, Hymenoptera, Diptera, and Lepidoptera, that harbor about 800,000 species altogether and therefore account for over 95% species diversity of this group (Peters et al., ).…”

“…Parthenogenetic taxa of the Holometabola are grouped below according to the insect orders to which they belong. Definitions of most common terms related to parthenogenesis are given in the Glossary in the first part of the review (Vershinina & Kuznetsova, ).…”

“…A few strains of predominantly arrhenotokous parasitoid species can exhibit haplodiploidy in the form of paternal genome elimination (PGE). Although PGE in the order Hymenoptera is definitely not as widespread as, for example, in many Coccoidea (Hemiptera; Vershinina & Kuznetsova, ), it was found in certain populations of three parasitoids that belong to the superfamily Chalcidoidea (Heimpel & de Boer, ; Werren & Stouthamer, ). Specifically, sex‐ratio distorters that are involved in PGE can be localized either on particular B chromosomes (the so‐called paternal sex ratio (PSR) ones), as in Nasonia vitripennis (Nur, Werren, Eickbush, Burke, & Eickbush, ) and Trichogramma kaykai Pinto et Stouthamer, 1997 (Trichogrammatidae; van Vugt, de Jong, & Stouthamer, ) or elsewhere, as in Encarsia pergandiella Howard, 1907 (Aphelinidae; Hunter, Nur, & Werren, ).…”

Characteristics of parthenogenesis in Cacopsylla ledi (Flor, 1861) (Hemiptera, Sternorryncha, Psylloidea): cytological and molecular approaches

“…Thelytoky can be obligatory if only parthenogenetic populations are present throughout the whole distribution range of a particular species. Nevertheless, it can be facultative if both bisexual and parthenogenetic reproduction occurs, with cyclical parthenogenesis in aphids as a well-known example (Normark 2003, Vershinina and Kuznetsova 2016). …”

Group-housed females promote production of asexual ootheca in American cockroaches

“…This specific form of parthenogenesis is known as “thelytoky,” in which females produce only females from unfertilized eggs [4]. For example, the speckled cockroach Nauphoeta cineria reproduces by facultative parthenogenesis; that is, some are capable of switching from a sexual mode of reproduction to an asexual mode when isolated from males [7, 8].…”