Population genetic and behavioral aspects of male mating monopolies in Cardiocondyla venustula

Susanne Jacobs
2020
The ant genus Cardiocondyla presumably comprises more than 100 species exhibiting a wide range of life-history strategies. The most striking feature is the existence of wingless, ergatoid (=worker-like) males in addition to or instead of the "standard" winged ant males. In several species, ergatoid males engage in lethal fighting to monopolize access to receptive female sexuals. Male morphology and mating strategies vary largely between species, as do traits like number of queens or colony
more » ... eens or colony size. Unlike in most other ant genera, mating takes place predominantly in the nest. Many Cardiocondyla species mate readily in the lab and therefore offer the opportunity to study several aspects of mating behavior in detail. The genus thus represents a fascinating model for the analysis of life history evolution, particularly the evolution of male morphology and male-male competition. Chapter 2 of this thesis reviews the current knowledge of male-male competition across ant species. The extent and nature of male competition varies with several factors, such as mating syndrome/location (male aggregation in aerial swarms vs. female calling with mating on the ground or intranidal mating) sex ratio, or number of mates per queen. While pre-copulatory competition has been studied for over a century, post-copulatory competition such as mating plugs or sperm competition in species with multiply mating queens has only come into focus in the course of the last decades. Pre-copulatory competition between ant males reaches from scramble competition in swarm-mating species to interference with other males' matings in species that mate on the ground, to lethal fighting in species of the genera Cardiocondyla and Hypoponera with intranidal mating. Within the genus Cardiocondyla, males of the study species of this thesis, C. venustula, revealed a competitive behavior yet undescribed for ants: wingless males spread out in the nest and defend small territories. This presumably marks a transition between males of species from tropics and the mon [...]
doi:10.5283/epub.43938 fatcat:in6frnsntvcnfcewndcs237xd4