Asynchronous hatching provides females with a means for increasing male care but incurs a cost by reducing offspring fitness

In species with biparental care, sexual conflict occurs because the benefit of care depends on the total amount of care provided by the two parents while the cost of care depends on each parent’s own contribution. Asynchronous hatching may play a role in mediating the resolution of this conflict over parental care. The sexual conflict hypothesis for the evolution of asynchronous hatching suggests that females adjust hatching patterns in order to increase male parental effort relative to female effort. We tested this hypothesis in the burying beetle Nicrophorus vespilloides by setting up experimental broods with three different hatching patterns: synchronous, asynchronous and highly asynchronous broods. As predicted, we found that males provided care for longer in asynchronous broods whereas the opposite was true of females. However, we did not find any benefit to females of reducing their duration of care in terms of increased lifespan or reduced mass loss during breeding. We found subs...在存在双亲抚育（biparental care）的物种中，性冲突（sexual conflict）时有发生：抚育收益取决于双亲共同提供的总抚育量，而抚育成本则仅与各亲本自身的投入相关。异步孵化（asynchronous hatching）可能在调控该亲本抚育相关冲突的解决过程中发挥作用。针对异步孵化演化的性冲突假说指出，雌性可通过调整孵化模式，提升雄性的亲本抚育投入占比，使其高于雌性自身的投入。我们以埋葬甲虫Nicrophorus vespilloides为研究对象验证该假说，通过设置包含三种不同孵化模式的实验育幼群：同步孵化群、异步孵化群与高度异步孵化群。实验结果与预期一致：雄性在异步孵化群中的抚育时长显著更长，而雌性则呈现相反趋势。然而，我们并未发现雌性缩短抚育时长能够为其带来任何收益，例如延长寿命或降低繁殖期间的体重损耗。我们的研究发现……