Ideas in Ecology and Evolution (Jan 2016)
Do gynogenetic species escape evolving enemies?
Abstract
Gynogenetic organisms are asexual females of one species that require sperm from males of another species to initiate reproduction (but except in rare instances of ‘paternal leakage’, those sperm do not contribute to the genetic make-up of the gynogens’ offspring). Gynogenetic organisms seem to combine disadvantages of both sexual and asexual reproductive strategies (e.g., mating costs, reduced genetic diversity). We borrowed logic from the Red Queen Hypothesis (RQH) to help explain the persistence of gynogenetic species in nature, which is a paradox. The RQH is the most oft-cited explanation for the maintenance of sex. It states that evolving enemies generate a constantly changing environment, which provides the conditions that make sex advantageous. Under this scenario, asexual organisms cannot evolve fast enough to ‘keep up’ with co-evolving parasites and disease causing organisms, and ultimately show reduced fitness compared to sexual individuals. The RQH tends to view asexuality generally, ignoring important nuance in nature like gynogenetic species in mixed assemblages with closely related sexual species. We outline tests of the argument that sperm dependency prevents asexual gynogens from outcompeting sexuals in mixed species assemblages and that this further allows gynogens to escape evolving enemies.
