Data from: Trust thy neighbour in times of trouble: background risk alters how tadpoles release and respond to disturbance cues

In aquatic environments, uninjured prey escaping a predator release chemical disturbance cues into the water. However, it is unknown whether these cues are a simple physiological by-product of increased activity or whether they represent a social signal that is under some control by the sender. Here, we exposed wood frog tadpoles (<i>Lithobates sylvaticus</i>) to either a high or low background risk environment and tested their responses to disturbance cues (or control cues) produced by tadpoles from high-risk or low-risk backgrounds. We found an interaction between risk level associated with the cue donor and cue recipient. While disturbance cues from low-risk donors did not elicit an antipredator response in low-risk receivers, they did in high-risk receivers. In addition, disturbance cues from high-risk donors elicited a marked antipredator response in both low- and high-risk receivers. The response of high-risk receivers to disturbance cues from high-risk donors was commensurate to other treatments, indicating an all-or-nothing response. Our study provides evidence of differential production and perception of social cues and provides insights into their function and evolution in aquatic vertebrates. Given the widespread nature of disturbance cues in aquatic prey, there may exist a social signalling system that remains virtually unexplored by ecologists.在水生环境中，未受伤的猎物在逃离捕食者时会向水体中释放化学扰动线索（chemical disturbance cues）。然而目前尚不明确，这类线索究竟只是活动增强时产生的简单生理副产物，还是由释放者主动调控的社会信号。本研究将林蛙蝌蚪（*Lithobates sylvaticus*）暴露于高背景风险与低背景风险两种环境中，并测试其对来自高风险或低风险背景的蝌蚪所产生的化学扰动线索（或对照线索control cues）的响应。本研究发现，扰动线索释放者与接收者对应的风险水平之间存在显著交互效应：低风险背景释放者所产生的扰动线索，无法在低风险接收者中诱发反捕食响应（antipredator response），但可在高风险接收者中触发此类响应；此外，高风险背景释放者所产生的扰动线索，可在低、高风险两类接收者中均诱发显著的反捕食响应。高风险接收者对高风险释放者所产生的扰动线索的响应强度与其他实验处理组相当，表明该响应呈现全有或全无的特征。本研究为社会信号的产生与感知存在差异提供了实验证据，并为水生脊椎动物中这类信号的功能与演化机制提供了新的研究视角。鉴于化学扰动线索在水生猎物类群中广泛分布，或许存在一套尚未被生态学家深入探究的社会信号传导系统。