Data from: Sex-specific responses to territorial intrusions in a communication network: evidence from radio-tagged great tits

Signals play a key role in the ecology and evolution of animal populations, influencing processes such as sexual selection and conflict resolution. In many species, sexually selected signals have a dual function: attracting mates and repelling rivals. Yet, to what extent males and females under natural conditions differentially respond to such signals remains poorly understood, due to a lack of field studies that simultaneously track both sexes. Using a novel spatial tracking system, we tested whether or not the spatial behavior of male and female great tits (Parus major) changes in relation to the response of a territorial male neighbor to an intruder. We tracked the spatial behavior of male and female great tits (N = 44), 1 hr before and 1 hr after simulating territory intrusions, employing automatized Encounternet radio-tracking technology. We recorded the spatial and vocal response of the challenged males and quantified attraction and repulsion of neighboring males and females to the intrusion site. We additionally quantified the direct proximity network of the challenged male. The strength of a male’s vocal response to an intruder induced sex-dependent movements in the neighborhood, via female attraction and male repulsion. Stronger vocal responders were older and in better body condition. The proximity networks of the male vocal responders, including the number of sex-dependent connections and average time spent with connections, did not change directly following the intrusion. The effects on neighbor movements suggest that the strength of a male’s vocal response can provide relevant social information to both the males and the females in the neighborhood, resulting in both sexes adjusting their spatial behavior in contrasting ways, while the social proximity network remained stable. Moreover, our study underlines the importance of the “silent” eavesdroppers within communication networks for studying the dual functioning and evolution of sexually selected signals.

信号在动物种群的生态学与演化进程中发挥核心作用，可对性选择、冲突解决等过程产生重要影响。在诸多物种中，经性选择演化的信号具备双重功能：既可吸引配偶，亦可威慑竞争者。然而，由于缺乏同时追踪雌雄两性的野外研究，自然条件下雌雄个体对这类信号的差异化响应程度仍未得到充分阐释。本研究依托一套新型空间追踪系统，探究了雄性大山雀（Parus major）的领地邻居对入侵个体的响应，是否会引发雌雄大山雀的空间行为改变。研究采用自动化Encounternet无线电追踪技术，在模拟领地入侵前后各1小时内，追踪了44只雌雄大山雀的空间行为。研究人员记录了受入侵雄鸟的空间与鸣唱响应，并量化了周边雌雄个体对入侵位点的吸引与排斥反应。此外，本研究还量化了受入侵雄鸟的直接邻近社交网络。雄鸟对入侵个体的鸣唱响应强度，可通过吸引雌性、排斥雄性的路径，引发周边个体的性别依赖性移动。鸣唱响应更强的雄鸟，往往年龄更大、身体状况更佳。受入侵雄鸟的邻近社交网络（包括性别依赖性连接数量、与连接对象的平均共处时长）在入侵发生后并未出现直接变化。对周边个体移动的影响表明，雄鸟的鸣唱响应强度可为周边雌雄个体提供关联社交信息，使得两性以相反的方式调整自身空间行为，同时社交邻近网络保持稳定。此外，本研究强调了通信网络中“沉默的偷听者”在探究性选择信号的双重功能与演化过程中的重要意义。