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, ...