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

general dataset:
Mating behaviour and offspring fitness dataset.

viability dataset:
Sperm viability dataset.

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 that did not experience fighting. Results suggest a trade-off in resource allocation between pre- and post-mating episodes of sexual selection. Despite lower ejaculate quality we found no fitness costs (fecundity and viability of offspring) for females mated to winners. Overall our findings highlight the importance of considering fighting ability when assessing male reproductive success, as winners may be impaired in their competitiveness at a post-mating level.

通用数据集：交配行为与后代适合度数据集。
活力数据集：精子活力数据集。

已知雄性间争斗竞争的结果会影响雄性交配成功率，且学界推测雌性通过偏好优势雄性可获得适合度收益。然而，与争斗胜者交配的雌性，可能承受显著成本，范围涵盖繁殖力下降以及对后代产生的负面影响。因此，厘清雄性优势对雌性适合度的成本与收益，对解析两性间利益冲突的潜在可能性至关重要。本研究以双斑蟋（Gryllus bimaculatus）为实验对象，探究单次争斗对决后雄性的交配前与交配后生殖投入，及其对雌性适合度的影响。实验中，我们先让雄性个体进行争斗，随后即刻测定其交配行为、精子质量与后代活力。研究发现：无论争斗结果如何，经历过争斗的雄性均会延迟交配，但求偶投入未受影响。不过，与败北雄性及未经历争斗的雄性相比，争斗胜者的精子质量（活力）更低。结果表明，在性选择的交配前与交配后阶段之间，存在资源分配的权衡取舍。尽管射精质量较低，但我们并未发现与胜者交配的雌性存在适合度成本——即后代的繁殖力与活力未受负面影响。综上，本研究结果凸显了在评估雄性生殖成功率时考量争斗能力的重要性：胜者在交配后层面的竞争力可能受损。