Eco-evolutionary dynamics of sexual selection and sexual conflict

The research framework of eco-evolutionary dynamics is increasing in popularity, as revealed by a steady stream of review articles and a recent and influential book, but primary empirical research is lagging behind. Moreover, the few empirical case studies demonstrating eco-evolutionary dynamics might not be entirely representative. Much current research on eco-evolutionary dynamics is focused on how ecological interactions lead to natural selection on phenotypic traits ("eco-evo"), and in turn how the evolutionary change in such traits feed back on ecological dynamics ("evo-eco"). A key feature of eco-evolutionary dynamics is thus a feedback loop between ecology (e.g., population dynamics) and evolution (i.e., genetic change). In contrast to previous research on eco-evolutionary dynamics driven by natural selection, the role of eco-evolutionary feedbacks in sexual selection and sexual conflict is largely unknown. Here, I review theory and the limited empirical evidence in this area and identify some promising future lines of research. I update a past review on contemporary evolution of secondary sexual traits in natural populations and formulate six explicit and rigorous criteria for contemporary evolution of secondary sexual traits by natural or sexual selection or sexual conflict. I then discuss the other key prediction of eco-evolutionary dynamics (i.e., evolution by sexual selection or sexual conflict shapes ecological dynamics). My overview reveals that our current knowledge in this area is limited and mainly come from theoretical models and laboratory experiments. A major challenge in eco-evolutionary dynamics is therefore to link ecological and population dynamics with sexual selection and sexual conflict. This is not an easy task but might be possible with carefully chosen study systems and methods.