Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.
Zukunftskolleg, University of Konstanz, Konstanz, Germany.
Elife. 2022 Jul 19;11:e76344. doi: 10.7554/eLife.76344.
Predation is one of the main evolutionary drivers of social grouping. While it is well appreciated that predation risk is likely not shared equally among individuals within groups, its detailed quantification has remained difficult due to the speed of attacks and the highly dynamic nature of collective prey response. Here, using high-resolution tracking of solitary predators (Northern pike) hunting schooling fish (golden shiners), we not only provide insights into predator decision-making, but show which key spatial and kinematic features of predator and prey predict the risk of individuals to be targeted and to survive attacks. We found that pike tended to stealthily approach the largest groups, and were often already inside the school when launching their attack, making prey in this frontal 'strike zone' the most vulnerable to be targeted. From the prey's perspective, those fish in central locations, but relatively far from, and less aligned with, neighbours, were most likely to be targeted. While the majority of attacks were successful (70%), targeted individuals that did manage to avoid being captured exhibited a higher maximum acceleration response just before the attack and were further away from the pike's head. Our results highlight the crucial interplay between predators' attack strategy and response of prey underlying the predation risk within mobile animal groups.
捕食是社会群体形成的主要进化驱动因素之一。尽管人们普遍认识到,捕食风险在群体内部的个体之间可能不会平均分担,但由于攻击速度和集体猎物反应的高度动态性,其详细量化一直很困难。在这里,我们使用对单独捕食者(北方梭子鱼)捕食成群鱼类(金鳞鱼)的高分辨率追踪,不仅深入了解了捕食者的决策过程,还展示了捕食者和猎物的哪些关键空间和运动特征预测了个体被攻击的风险以及攻击后能否存活。我们发现,梭子鱼往往会悄悄接近最大的鱼群,并且在发动攻击时经常已经在鱼群内部,使得位于这个正面“攻击区”的猎物最容易成为攻击目标。从猎物的角度来看,那些位于中心位置但距离相对较远且与邻居对齐程度较低的鱼最有可能成为目标。尽管大多数攻击都是成功的(70%),但那些成功避免被捕食的目标个体在攻击前的最大加速度反应更高,并且离梭子鱼的头部更远。我们的研究结果强调了捕食者的攻击策略和猎物的反应在移动动物群体中的捕食风险中起着至关重要的相互作用。