The Evolution of Sexually Antagonistic Phenotypes

Sexual conflict occurs whenever there is sexually antagonistic selection on shared traits. When shared traits result from interactions (e.g., mating rate) and have a different genetic basis in each sex (i.e., interlocus conflict), then sex-specific traits that shift the value of these interaction traits toward the sex-specific optimum will be favored. Male traits can be favored that increase the fitness of their male bearers, but decrease the fitness of interacting females. Likewise, female traits that reduce the costs of interacting with harmful males may simultaneously impose costs on males. If the evolution of these antagonistic traits changes the nature of selection acting on the opposite sex, interesting coevolutionary dynamics will result. Here we examine three current issues in the study of sexually antagonistic interactions: the female side of sexual conflict, the ecological context of sexual conflict, and the strength of evidence for sexually antagonistic coevolution.