Data from: Honey bee inhibitory signaling is tuned to threat severity and can act as a colony alarm signal

Alarm communication is a key adaptation that helps social groups resist predation and rally defenses. In Asia, the world's largest hornet, Vespa mandarinia, and the smaller hornet, Vespa velutina, prey upon foragers and nests of the Asian honey bee, Apis cerana. We attacked foragers and colony nest entrances with these predators and provide the first evidence, in social insects, of an alarm signal that encodes graded danger and attack context. We show that like A. mellifera, A. cerana possesses a vibrational "stop signal", which can be triggered by predator attacks upon foragers, and inhibits waggle dancing. Large hornet attacks were more dangerous and resulted in higher bee mortality. Per attack at the colony-level, large hornets elicited more stop signals than small hornets. Unexpectedly, stop signals elicited by large hornets (SS large hornet) had a significantly higher vibrational fundamental frequency than those elicited by small hornets (SS small hornet) and were more effective at inhibiting waggle dancing. Stop signals resulting from attacks upon the nest entrance (SS nest) were produced by foragers and guards and were significantly longer in pulse duration than stop signals elicited by attacks upon foragers (SS forager). Unlike SS forager, SS nest were targeted at dancing and non-dancing foragers and had the common effect, tuned to hornet threat level, of inhibiting bee departures from the safe interior of the nest. Meanwhile, nest defenders were triggered by bee alarm pheromone and live hornet presence to heatball the hornet. In A. cerana, the waggle dance, sophisticated recruitment communication that encodes food location, is therefore matched with an inhibitory/alarm signal that encodes information about the context of danger and its threat level.

警报通讯是帮助社会性群体抵御捕食、集结防御的关键适应性策略。在亚洲，世界体型最大的胡蜂——大虎头蜂(Vespa mandarinia)与体型较小的黄脚胡蜂(Vespa velutina)会捕食东方蜜蜂(Apis cerana)的采集蜂与蜂群巢穴。本研究通过模拟上述两类捕食者对采集蜂与蜂群巢门的攻击行为，首次在社会性昆虫中证实了一类可编码分级危险程度与攻击场景的警报信号。研究发现，与西方蜜蜂(Apis mellifera)类似，东方蜜蜂也存在一类振动性停止信号(stop signal)：该信号可由捕食者攻击采集蜂事件触发，并能抑制摇摆舞行为。大虎头蜂的攻击危险性更高，会导致更高的蜜蜂死亡率；在蜂群层面的单次攻击中，大虎头蜂诱发的停止信号数量多于小黄脚胡蜂。出乎意料的是，大虎头蜂诱发的停止信号(SS large hornet)的振动基频显著高于小黄脚胡蜂诱发的停止信号(SS small hornet)，且对摇摆舞行为的抑制效果更强。由巢门攻击诱发的停止信号(SS nest)由采集蜂与守卫蜂产生，其脉冲时长显著长于由采集蜂攻击诱发的停止信号(SS forager)。与SS forager不同，SS nest的作用对象为正在进行摇摆舞与未进行摇摆舞的采集蜂，且其抑制蜜蜂从安全的蜂群内部向外出动的效果会随胡蜂威胁等级动态调整。与此同时，蜂群守卫蜂会在蜜蜂报警信息素与活体胡蜂的双重触发下，通过抱团加热的方式击杀胡蜂。由此可见，在东方蜜蜂中，作为编码食物位置的复杂招募通讯行为的摇摆舞，与一类可编码危险场景与威胁程度的抑制性/警报信号形成了完整的配套通讯系统。