Flexibility in task performance and division of labour in a cooperatively breeding cichlid

Abstract

Division of labour is a key feature of cooperative social systems, where task specialization among individuals enhances group efficiency. In the cooperatively breeding cichlid Neolamprologus pulcher reproductive division of labour exists, where a dominant breeding pair reproduces while subordinates help in rearing the offspring and perform various tasks to gain acceptance within the group. Larger helpers engage in territory maintenance and predator defence while smaller helpers focus on egg care and deterrence of egg predators. Here we investigated task specialisation, division of labour and the dynamics of coordination of tasks in N. pulcher groups of natural size and composition. In lab experiments, we assessed whether helpers consistently specialized in sand removal from territories or in egg predator defence when both tasks were presented simultaneously. While different size classes performed both tasks, task performance was not repeatable, and there was no clear division of labour. Dominant females did most work, with the helpers often remaining idle. Lag sequence analysis revealed that individuals were significantly more likely to take up a task if it had just been performed by another individual, rather than dividing labour between individuals - a phenomenon we term "task contagion". This suggests that individuals respond to immediate group needs, offering new insights into how cooperative breeders can adapt to changing task demands by flexible behaviour and potentially enhance group efficiency. Significance statementCooperatively breeding vertebrates exhibit complex social structures and group dynamics, one notable feature being division of labour. However, unlike eusocial insects, these vertebrates display a high degree of flexibility in task allocation among group members. In a laboratory experiment, we investigated the dynamics of task allocation and coordination in groups of the cooperatively breeding cichlid Neolamprologus pulcher. We simultaneous induced demands for both territory maintenance and territory defence against egg predators. Task performance and the degree of specialisation varied across size classes and between different groups, and were not repeatable. Using high-resolution event data, we identified a tendency for individuals to follow others in the execution of the same task, a phenomenon we have termed task contagion.