Sexual conflict between males and females is recognized as a powerful force in the evolution of reproductive tactics and physiology. In promiscuous mating systems, conflict can lead to the development of male traits that increase the females¿ present breeding efforts but negatively affect their longevity and future fecundity. This appears to be dramatically different in perennial social insects, such as ants. Due to their life history, the reproductive interests of males and queens are expected to converge even when females mate multiply: colonies have to grow for a prolonged period of time before sexuals are produced. Males can therefore gain only from a high queen lifetime reproductive success and do not benefit from boosting their short-term fecundity. Yet, sperm competition between male ejaculates might occur in polyandrous queens. I attempt to investigate the implications of relaxed sexual conflict and varying levels of sperm competition on males and queens in the ant species Cardiocondyla obscurior by ethological, genetic, and histological studies. As the species express two different male morphs, which represent alternative reproductive tactics and experience different probabilities of sperm competition, this research might yield insight into the consequences of sperm competition on male traits and their effects on female reproductive success.
