Abstract

In cooperative breeding groups, dominant and subordinate members often engage in exchanges of different resources, involving ongoing negotiation. For instance, helpers may trade alloparental brood care in exchange for safety and access to resources within the dominants’ territory. In this study, we aim to investigate the pay-to-stay hypothesis, which suggests that breeders will escalate punishment as the duration of the helper’s transgression increases. For that, we use the cooperative breeder Neolamprologus pulcher, a cichlid fish from Lake Tanganyika as a model species. Additionally, we examine whether unrelated helpers respond to increased aggression by providing more assistance, as predicted by pay-to-stay negotiation dynamics. Our findings reveal that breeders indeed intensified aggression as the duration of helper transgression grew, utilizing more aggressive forms of punishment over time. Furthermore, we observed that digging in the breeding chamber increased in response to punishment, while the provision of brood care only showed a positive correlation with the level of assistance needed. This suggests that alloparental care by unrelated helpers is driven by coercion but expected help compensation may depend on the specific commodity studied.