Data from: Power and temptation cause shifts between exploitation and cooperation in a cleaner wrasse mutualism

In many instances of cooperation, only one individual has both the potential and the incentive to ‘cheat’ and exploit its partner. Under these asymmetric conditions, a simple model predicts that variation in the temptation to cheat and in the potential victim's capacity for partner control leads to shifts between exploitation and cooperation. Here, we show that the threat of early termination of an interaction was sufficient to induce cleaner wrasse Labroides dimidiatus to feed selectively against their preference (which corresponds to cooperatively eating client fish ectoparasites), provided that their preference for alternative food was weak. Under opposite conditions, cleaners fed selectively according to their own preference (which corresponds to cheating by eating client mucus). By contrast, a non-cleaning fish species, Halichoeres melanurus, failed to adjust its foraging behaviour under these same conditions. Thus, cleaners appear to have evolved the power to strategically adjust their levels of cooperation according to the circumstances.

在诸多合作情境中，往往仅单个个体同时具备“欺骗”并利用合作伙伴的潜力与动机。在此类不对称条件下，一个简单模型预测：欺骗诱惑与潜在受害者的伙伴控制能力二者的差异，会引发合作与利用行为之间的转换。本研究表明，当清洁鱼（Labroides dimidiatus）对替代食物的偏好较弱时，互动提前终止的威胁足以促使其违背自身偏好进行选择性进食——这对应于合作性取食客户鱼体外寄生虫的行为。而在相反条件下，清洁鱼则会依据自身偏好进行选择性进食——这对应于取食客户鱼黏液的欺骗行为。与之相对，非清洁性鱼类物种黑背海猪鱼（Halichoeres melanurus）在相同实验条件下无法调整其觅食行为。由此可见，清洁鱼似乎已演化出根据环境策略性调整合作水平的能力。