Data from: Replacing bold individuals has a smaller impact on group performance than replacing shy individuals

In many animal societies just one or few individuals, referred to as keystone individuals, can have a disproportionately large impact on collective outcomes. Despite ongoing interest in the consequences of losing a keystone individual on group performance, little is known about whether other individuals with an appropriate behavioral type can readily assume the keystone role. Here we examine if the identity of a keystone individual impacts its influence on the collective behavior of its group in a society of social spiders. We find that the repeated replacement of a keystone individual, which is typically a group’s boldest constituent, has little impact on the collective prey capture of the colony. However, repeatedly replacing a shy, generic, individual in the group reduces prey capture success. Groups in which the keystone individual is repeatedly replaced increase their overall boldness, thus potentially collectively substituting the bold behavioral type that they lost. Furthermore, newly replaced keystone individuals participate in a greater proportion of prey attacks than established keystone individuals in undisturbed colonies, as seen in prior work on colony social development, suggesting that the repeated replacement of a keystone individual maintains colonies in an early stage of social succession. By uncovering the mechanisms that underlie a group’s robustness to social perturbations, our work sheds light on how social dynamics dictate colony-level phenotypes in animal groups.

在诸多动物社会中，仅单个或少数被称为关键个体（keystone individuals）的成员，会对群体整体结果产生远超其自身权重的显著影响。尽管学界持续关注丧失关键个体对群体表现的影响，但目前对于具备合适行为类型的其他个体能否顺利接任关键个体的角色，仍知之甚少。本研究以群居蜘蛛社会为模型，探究关键个体的身份是否会影响其对群体集体行为的调控作用。研究发现，对通常作为群体中最大胆成员的关键个体进行反复替换，并不会对蛛群的集体捕食行为产生明显影响。但反复替换群体中腼腆的普通个体，则会降低捕食成功率。那些关键个体被反复替换的蛛群，整体大胆程度会有所提升，从而可能通过集体行为补充了其所缺失的大胆行为类型。此外，与未受干扰的蛛群中的既定关键个体相比，新替换的关键个体参与捕食攻击的比例更高——这一结果与此前关于蛛群社会发育的研究结论一致，表明反复替换关键个体可使蛛群维持在社会演替的早期阶段。本研究通过揭示群体对社会扰动具备鲁棒性的内在机制，阐明了社会动态如何调控动物群体的集群表型（colony-level phenotypes）。