Collective behaviour, social interactions and leadership in animal groups are often driven by individual differences. However, most studies focus on same-species groups, in which individual variation is relatively low. Multispecies groups, however, entail interactions among highly divergent phenotypes, ranging from simple exploitative actions to complex coordinated networks. Here we studied hunting groups of otherwise-solitary Octopus cyanea and multiple fish species, to unravel hidden mechanisms of leadership and associated dynamics in functional nature and complexity, when divergence is maximized. Using three-dimensional field-based tracking and field experiments, we found that these groups exhibit complex functional dynamics and composition-dependent properties. Social influence is hierarchically distributed over multiscale dimensions representing role specializations: fish (particularly goatfish) drive environmental exploration, deciding where, while the octopus decides if, and when, the group moves. Thus, ‘classical leadership’ can be insufficient to describe complex heterogeneous systems, in which leadership instead can be driven by both stimulating and inhibiting movement. Furthermore, group composition altered individual investment and collective action, triggering partner control mechanisms (that is, punching) and benefits for the de facto leader, the octopus. This seemingly non-social invertebrate flexibly adapts to heterospecific actions, showing hallmarks of social competence and cognition. These findings expand our current understanding of what leadership is and what sociality is.

动物群体的集体行为、社会互动和领导能力往往是由个体差异驱动的。然而，大多数研究都集中在同一物种群体上，其中个体差异相对较小。然而，多物种群体需要高度不同的表型之间的相互作用，从简单的开发行为到复杂的协调网络。在这里，我们研究了其他孤立的章鱼 cyanea 和多种鱼类的狩猎群体，以揭示当分歧最大化时，功能性质和复杂性中隐藏的领导机制和相关动态。使用基于三维场的跟踪和现场实验，我们发现这些组表现出复杂的功能动力学和成分依赖性。社会影响力在代表角色特化的多尺度维度上分层分布：鱼（尤其是山羊鱼）推动环境探索，决定群体在哪里移动，而章鱼决定群体是否以及何时移动。因此，“经典领导力”可能不足以描述复杂的异质系统，在这些系统中，领导力可以由刺激和抑制运动驱动。此外，集团构成改变了个人投资和集体行动，触发了合作伙伴控制机制（即拳打脚踢）和事实上的领导者章鱼的好处。这种看似非社会性的无脊椎动物灵活地适应异种行为，表现出社会能力和认知的特征。这些发现扩展了我们目前对领导力和社会性的理解。