'Selfish herds' of guppies follow complex rather than simple rules when information is not limited

Under the threat of predation, animals can decrease their level of risk by moving towards other individuals to form compact groups. A significant body of theoretical work has proposed multiple movement rules, varying in complexity, which might underlie this process of aggregation. However, if and how animals use these rules to form compact groups is still not well understood, and how environmental factors affect the use of these rules even less so. Here, we evaluate the success of different movement rules, by comparing their predictions with the movement seen when shoals of guppies (Poecilia reticulata) form under the threat of predation. We repeated the experiment in a turbid environment to assess how the use of the movement rules changed when visual information is reduced. During a simulated predator attack, guppies in clear water used complex rules that took multiple neighbours into account, forming compact groups. In turbid water, the difference between all rule predictions and fish...

在捕食威胁下，动物可通过向同类个体移动以形成紧凑群体来降低自身风险水平。大量理论研究提出了多种复杂度各异的运动规则，这些规则或为聚集过程的底层机制。然而，动物是否及如何利用这些规则形成紧凑群体的机制仍未明确，环境因素对这些规则使用的影响则知之更少。在此，我们通过将不同运动规则的预测结果与孔雀鱼（Poecilia reticulata）在捕食威胁下形成鱼群时的运动行为进行对比，评估这些规则的有效性。我们在浑浊环境中重复实验，以评估视觉信息减少时动物对运动规则的使用变化。在模拟捕食者攻击时，清水环境中的孔雀鱼采用考虑多个邻近个体的复杂规则，形成紧凑群体。而在浑浊水中，所有规则预测结果与鱼...