Impaired sperm quality, delayed mating but no costs for offspring fitness in crickets winning a fight

The outcome of male-male contest competition is known to affect male mating success and is believed to confer fitness benefits to females through preference for dominant males. However, by mating with contest winners, females can incur significant costs spanning from decreased fecundity to negative effects on offspring. Hence identifying costs and benefits of male dominance on female fitness is crucial to unravel the potential for a conflict of interests between the sexes. Here we investigated males’ pre- and post-copulatory reproductive investment and its effect on female fitness after a single contest a using the field cricket Gryllus bimaculatus. We allowed males to fight, and immediately measured their mating behaviour, sperm quality, and offspring viability. We found that males experiencing a fight, independently of the outcome, delayed matings but their courtship effort was not affected. However, winners produced sperm of lower quality (viability) compared to losers and to males t...