Selection for collective aggressiveness favors social susceptibility in social spiders

Particularly socially influential individuals are present in many groups, but it is unclear whether their emergence is determined by their social influence versus the social susceptibility of others. The social spider Stegodyphus dumicola shows regional variation in apparent leader-follower dynamics. We use this variation to evaluate the relative contributions of leader social influence versus follower social susceptibility in driving this social order. Using chimeric colonies that combine potential leaders and followers, we discover that leader-follower dynamics emerge from the site-specific social susceptibility of followers. We further show that the presence of leaders increases colony survival in environments where leader-follower dynamics occur. Thus, leadership is driven by the “social susceptibility” of the population majority, rather than the social influence of key group members.

诸多群居类群中均存在社会影响力突出的个体，但目前尚未明确这类个体的出现究竟是由其自身的社会影响力所决定，还是缘于其他群体成员的社会易感性（social susceptibility）。群居蜘蛛Stegodyphus dumicola在表观的领导者-追随者动态模式上存在区域变异。我们借助这一区域变异，评估在驱动该社会秩序形成的过程中，领导者的社会影响力与追随者的社会易感性各自的相对贡献。通过构建融合潜在领导者与追随者的嵌合群居群，我们发现，领导者-追随者的动态模式实则源自追随者的位点特异性社会易感性。我们进一步证实，在存在领导者-追随者动态模式的环境中，领导者的存在可提升群居群的存活率。综上，群体领导力的形成实则取决于种群多数个体的社会易感性，而非核心群体成员的社会影响力。