Cooperation between the sexes in the ant genus Cardiocondyla

• Applicant: Dr. Alexandra Schrempf
• Subject Area: Evolution, Anthropology
• Term: from 2009 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 135067204

Mating partners in promiscuous animals may have opposing interests about the future reproductive performance of the female. Males gain most through forcing it to invest maximally in short-term reproduction, while females often benefit more from re-mating and saving resources for future clutches. This sexual conflict has led to the evolution of male genital structures and seminal fluids, which harm the females, prevent them from re-mating, and / or decrease their life expectancy, and to respective counter-measures in the females. In species with lifelong pair-bonding, such as social Hymenoptera (bees, ants, wasps), sexual conflict is not expected and sexuals should instead aim at cooperating. In the maledimorphic ant Cardiocondyla obscurior, mating itself is beneficial for females in that it increases their life spans. Interestingly, mating with winged males has a stronger effect on the life span and reproductive success of queens than mating with wingless males. As males neither provide nuptial gifts nor any other assistance after mating, we hypothesize that seminal fluids play a crucial role. Elucidating the proximate mechanisms of sexual cooperation might help to achieve a better understanding of the bizarre interrelations between mating, reproduction, senescence, and longevity in social insects in general. To gain insight into the mechanisms of sexual cooperation, we intend toa) investigate the composition of seminal fluids transferred by the different types of males during copulation by two-dimensional electrophoresis (DIGE), representational difference analysis of gene expression in male accessory glands, and gas chromatography, and to compare the data with those obtained from other social Hymenoptera, in particular the honey bee, and Leptothorax gredleri,b) conduct a demographic analysis of the different patterns of mortality and reproductive senescence in a much number of queens mated to the two different types of males,c) quantify the behavior of workers towards the queens to determine whether and how the social environment might be involved in the different pattern of mortality,d) investigate, by cross-breeding experiments, whether co-evolution has resulted in the life-prolonging effect of mating being stronger when partners are from the same population than when they are from distant populations,e) examine whether winged males have a stronger effect also in other male-dimorphic Cardiocondyla species.

• DFG Programme: Research Grants
• International Connection: Brazil
• Participating Persons: Professor Dr. Klaus Hartfelder; Professor Dr. Jürgen Heinze