Social transmission in the wild reduces predation pressure on novel prey signals

Social transmission of information is taxonomically widespread and could have profound effects on the ecological and evolutionary dynamics of animal communities. Demonstrating this in the wild, however, has been challenging. Here we show by field experiment that social transmission among predators can shape how selection acts on prey defences. Using artificial prey and a novel approach in statistical analyses of social networks, we find that blue tit (Cyanistes caeruleus) and great tit (Parus major) predators learn about prey defences by watching others. This shifts population preferences rapidly to match changes in prey profitability, and reduces predation pressure from naïve predators. Our results may help resolve how costly prey defences are maintained despite influxes of naïve juvenile predators, and suggest that accounting for social transmission is essential if we are to understand coevolutionary processes.

信息的社会传播在分类学上分布广泛，且可能对动物群落的生态与进化动态产生深远影响。然而，在野外环境中验证这一结论颇具挑战。本研究通过野外实验证实，捕食者间的社会传播可塑造选择作用于猎物防御策略的方式。本研究使用人工猎物及一种全新的社交网络统计分析方法，发现捕食者青山雀（Cyanistes caeruleus）与大山雀（Parus major）可通过观察同类来习得猎物防御相关信息。这一过程会快速调整种群的取食偏好，以匹配猎物收益性的变化，并降低无经验捕食者带来的捕食压力。本研究结果或有助于解释：即便有大量无经验幼龄捕食者迁入，高成本的猎物防御策略仍能得以维持；同时表明，若要理解协同进化过程，纳入社会传播因素是不可或缺的。