In species that provide biparental care, there is sexual conflict between parents over how much each should contribute towards caring for their joint offspring. Theoretical models for the resolution of this conflict through behavioral negotiation between parents assume that parents cannot assess their partner’s state directly but do so indirectly by monitoring their partner's contribution. Here, we test whether parents can assess their partner’s state directly by investigating the effect of nutritional state on cooperation between parents in the burying beetle Nicrophorus vespilloides. We used a two-by-two factorial design, in which a well-fed or food-deprived female was paired with a well-fed or food-deprived male. We found that females adjusted their level of care in response to both their own nutritional state and that of their partner and that these decisions were independent of their partner’s contribution. We found no evidence that males responded directly to nutritional state. Males instead responded indirectly based on the contribution of their partner. Our results suggest that parents are able to assess the state of their partner, in contrast to what has been assumed, and that these assessments play an important role in the mediation of sexual conflict between caring parents.

中文翻译：

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灵活的雌性：营养状态影响埋葬甲虫的双亲合作

在提供双亲照顾的物种中，父母之间在各自应该为照顾共同后代做出多少贡献方面存在性别冲突。通过父母之间的行为协商解决这种冲突的理论模型假设父母不能直接评估伴侣的状态，而是通过监控伴侣的贡献来间接评估。在这里，我们通过调查埋葬甲虫 Nicrophorus vespilloides 中营养状态对父母之间合作的影响来测试父母是否可以直接评估其伴侣的状态。我们采用了二乘二的析因设计，将喂养良好或食物匮乏的雌性与喂养良好或食物匮乏的雄性配对。我们发现，女性会根据自己的营养状况和伴侣的营养状况来调整自己的护理水平，并且这些决定与伴侣的贡献无关。我们没有发现任何证据表明男性对营养状态有直接反应。相反，雄性根据伴侣的贡献间接做出反应。我们的结果表明，与假设相反，父母能够评估其伴侣的状态，并且这些评估在调解关爱父母之间的性冲突中发挥着重要作用。