Data from: Social-bond strength influences vocally-mediated recruitment to mobbing

Strong social bonds form between individuals in many group-living species, and these relationships can have important fitness benefits. When responding to vocalizations produced by groupmates, receivers are expected to adjust their behaviour depending on the nature of the bond they share with the signaller. Here we investigate whether the strength of the signaller–receiver social bond affects response to calls that attract others to help mob a predator. Using field-based playback experiments on a habituated population of wild dwarf mongooses (Helogale parvula), we first demonstrate that a particular vocalization given on detecting predatory snakes does act as a recruitment call; receivers were more likely to look, approach and engage in mobbing behaviour than in response to control close calls. We then show that individuals respond more strongly to these recruitment calls if they are from groupmates with whom they are more strongly bonded (those with whom they preferentially groom and forage). Our study, therefore, provides novel evidence about the anti-predator benefits of close bonds within social groups.在诸多群居物种中，个体间会形成牢固的社会联结，这类关系对个体的适合度具有重要收益。当接收者对同伴发出的鸣声作出响应时，其行为调整理应取决于与信号发出者之间的联结性质。本研究旨在探究：信号发出者与接收者之间的社会联结强度，是否会影响接收者对招募同伴协助围捕捕食者的鸣声的响应。本研究针对已习惯人类干扰的野生矮獴（Helogale parvula）种群开展野外声学回放实验，首先证实：个体在侦测到捕食性蛇类时发出的特定鸣声确实属于招募鸣声；相较于对照鸣声，接收者更易表现出抬头观察、趋近声源并参与围捕捕食者的行为。本研究随后表明，当招募鸣声来自与其联结更为紧密的同伴——即优先与其开展理毛行为、共同觅食的个体时，接收者对该鸣声的响应强度显著更高。因此，本研究为社会群体内紧密社会联结所带来的反捕食收益提供了全新的实证证据。