Data for: Coercion promotes alloparental care in cooperative breeders

Members of social groups may negotiate among each other about the exchange of goods and services. If this involves asymmetries between interacting partners, for instance in condition, power or expected payoffs, coercion may be involved in the bargain. Cooperative breeders are excellent models to study such interactions, because asymmetries are inherent in the relationship between dominant breeders and subordinate helpers. Currently it is unclear whether punishment is used to enforce costly cooperation in such systems. Here we investigated experimentally in the cooperatively breeding cichlid <em>Neolamprologus pulcher</em> whether alloparental brood care provided by subordinates is contingent on enforcement by dominant breeders<em>.</em> We manipulated first the brood care behaviour of a subordinate group member and then the possibility of the dominant breeders to punish idle helpers. When subordinates abstained from brood care, breeders increased their attacks on them, which triggered increased alloparental brood car by helpers as soon as this was again possible. In contrast, when the possibility to punish helpers was prevented, energetically costly alloparental brood care did not increase. Our results confirm predictions of the pay-to-stay mechanism causing alloparental care in this species and they suggest more generally that coercion can play an important role in the control of cooperation.社会群体中的成员可就商品与服务的交换开展相互磋商。若互动双方存在不对等性——例如在自身状态、权力或预期收益层面——则议价过程中或伴随强制行为。合作繁殖者（cooperative breeders）是研究此类互动的理想模型，因优势繁殖者与从属协助者间的关系本身就固有不对等性。目前学界尚未明确此类系统中是否会通过惩罚手段维系高代价的合作行为。本研究以合作繁殖的慈鲷（cichlid）Neolamprologus pulcher为对象开展实验，旨在探究从属个体提供的异亲抚育（alloparental brood care）是否依赖优势繁殖者的强制约束。我们先后操控了某一从属群体成员的育幼行为，以及优势繁殖者惩罚怠工协助者的权限。当从属个体放弃育幼行为时，繁殖者会增强对其的攻击行为，这会促使协助者在条件恢复允许后立即提升异亲抚育投入。反之，若剥夺了繁殖者惩罚协助者的可能性，则高能耗的异亲抚育行为并未出现显著提升。本研究结果验证了「付费停留」（pay-to-stay）机制可诱发该物种异亲抚育行为的相关预测，同时更广泛地表明，强制行为在合作行为的调控中可发挥关键作用。