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.

许多群居物种的个体间会形成牢固的社会联结，这类社会关系往往能带来重要的适合度收益。当接收者回应群体同伴发出的鸣声时，理应根据自身与信号发出者之间的联结性质调整自身行为。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吸引同伴协助围攻捕食者的鸣声的反应。我们针对一个已习惯人类接触的野生矮獴（Helogale parvula）种群开展野外回放实验，首先证实了：当个体侦测到捕食性蛇类时发出的特定鸣声，确实属于招募呼叫；相较于对照的近距离鸣声，接收者更易出现抬头张望、靠近声源并参与围攻捕食者的行为。随后我们进一步发现：若招募呼叫来自与接收者联结更紧密的群体成员——即那些接收者优先与之理毛、共同觅食的个体，接收者的反应会更为强烈。因此，本研究为社会群体内部紧密联结所带来的反捕食收益提供了全新的实证证据。