Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter. EX4 4QG, UK.
Department of Biology and Department of Computer Science, University of York, York YO10 5DD, UK.
Sci Rep. 2017 Feb 2;7:41679. doi: 10.1038/srep41679.
Social relationships can have important consequences for fitness in animals. Whilst numerous studies have shown that individuals often join larger groups in response to perceived predation risk (i.e. fear of predation), the importance of predation risk in driving the formation and stability of social relationships within groups has been relatively ignored. We experimentally tested how predation threat influenced fine-scale social network structure using Trinidadian guppies (Poecilia reticulata). When perceived predation risk was high, individuals developed stable and more differentiated social ties compared to when perceived risk was low. Intriguingly, social differentiation coincided with shoals being somewhat smaller under high-perceived risk, suggesting a possible conflict between forming stable social relationships and larger social groups. Individuals most at risk of predation (large and bold individuals) showed the most exaggerated responses in several social measures. Taken together, we provide the first experimental evidence that proximate risk of predation can increase the intensity of social relationships and fine-scale social structure in animal populations.
社会关系对动物的适应度有重要影响。尽管许多研究表明，个体通常会为了应对感知到的捕食风险（即对捕食的恐惧）而加入更大的群体，但捕食风险在驱动群体内部社会关系的形成和稳定方面的重要性却相对被忽视了。我们使用特立尼达孔雀鱼（Poecilia reticulata）进行了实验，以检验捕食威胁如何影响微观尺度的社会网络结构。当感知到的捕食风险较高时，与感知风险较低时相比，个体形成了更稳定和更分化的社会联系。有趣的是，在高感知风险下，群体的大小略有减小，这表明在形成稳定的社会关系和更大的社会群体之间可能存在冲突。处于捕食风险最高的个体（大而大胆的个体）在几个社会指标上表现出最夸张的反应。总之，我们提供了第一个实验证据，表明接近的捕食风险可以增加动物种群中社会关系和微观社会结构的强度。
