Male fighting ability predicts harassment of females and copulation success in the Lake Eyre dragon lizard (#391)
Dominance in male-male contests is often correlated with reproductive success. This may be because competitively superior males monopolise access to females, are preferred by females, invest more into courtship or are more coercive. Differentiating these alternatives is essential to understand the interaction between male competition and female mate choice, and their influence on the evolution of male traits. We investigated how male fighting ability relates to behaviour in inter-sexual interactions and copulation success in the Australian Lake Eyre dragon lizard, Ctenophorus maculosus. We found that more dominant males have greater copulation success and employ a more coercive mating strategy. Males that harassed females more (with biting and chasing) also copulated for longer, which may increase sperm transfer and/or fertilisation success, and were rejected less by females. This is likely because females are unable to perform rejection behaviours (fleeing, lateral threat display or flip-over) while being bitten by males. Therefore, it appears that selection for superior fighting ability in male contests also selects for aggression towards females, which increases copulation success, generating mutually reinforcing selection. Females may gain indirect genetic benefits from mating with dominant males that outweigh the costs associated with sexual coercion, thus maintaining the mating system.