Plasticity of parental care under the risk of predation: how much should parents reduce care?

Predation can be an important agent of natural selection shaping parental care behaviours, and can also favor behavioural plasticity. Parent birds often decrease the rate that they visit the nest to provision offspring when perceived risk is high. Yet the plasticity of such responses may differ among species as a function of either their relative risk of predation, or the mean rate of provisioning. Here, we report parental provisioning responses to experimental increases in the perceived risk of predation. We tested responses of 10 species of birds in north temperate Arizona and subtropical Argentina that differed in their ambient risk of predation. All species decreased provisioning rates in response to the nest predator but not to a control. However, provisioning rates decreased more in species that had greater ambient risk of predation on natural nests. These results support theoretical predictions that the extent of plasticity of a trait that is sensitive to nest predation risk shou...

捕食作用是塑造亲本抚育行为的关键自然选择因子，同时亦可推动行为可塑性的演化。当感知到较高的捕食风险时，鸟类亲本通常会降低回巢饲喂幼鸟的频次。然而这类响应的可塑性在不同物种间存在差异，这取决于物种自身的相对捕食风险，或是平均饲喂速率。本研究针对感知捕食风险的实验性升高，探讨了鸟类亲本的饲喂响应模式。我们在北温带的亚利桑那州与亚热带的阿根廷地区，选取了10种本底捕食风险存在差异的鸟类作为受试对象，测试其响应表现。所有受试物种在模拟巢捕食者的处理下均降低了饲喂速率，但在对照组处理中未出现此类响应变化。不过，天然巢捕食风险更高的物种，其饲喂速率的下降幅度更为显著。上述结果支持了相关理论预测：即受巢捕食风险调控的性状，其可塑性程度应当...