Data from: Divergence in mating signals correlates with genetic distance and behavioural responses to playback

Animals use acoustic signals to defend resources against rivals and attract breeding partners. As with many biological traits, acoustic signals may reflect ancestry; closely related species often produce more similar signals than do distantly related species. Whether this similarity in acoustic signals is biologically relevant to animals is poorly understood. We conducted a playback experiment to measure the physical and vocal responses of male songbirds to the songs of both conspecific and allopatric-congeneric animals that varied in their acoustic and genetic similarity. Our subjects were territorial males of four species of neotropical Troglodytes wrens: Brown-throated Wrens (Troglodytes brunneicollis), Cozumel Wrens (T. beani), Clarion Wrens (T. tanneri), and Socorro Wrens (T. sissonii). Our results indicate that birds respond to playback of both conspecific and allopatric-congeneric animals; that acoustic differences increase with genetic distance; and that genetic divergence predicts the strength of behavioural responses to playback, after removing the effects of acoustic similarity between subjects’ songs and playback stimuli. Collectively, these results demonstrate that the most distantly related species have the most divergent songs, that male wrens perceive divergence in fine structural characteristics of songs, and that perceptual differences between species reflect evolutionary history. This study offers novel insight into the importance of acoustic divergence of learned signals and receiver responses in species recognition.动物借助声学信号（acoustic signals）抵御资源竞争者、吸引繁殖配偶。与诸多生物性状一样，声学信号可反映物种的亲缘关系：亲缘关系较近的物种所发出的信号通常比远缘物种更为相似。目前学界对这类声学信号的相似性是否对动物具有生物学意义仍知之甚少。我们开展了回放实验（playback experiment），以测定雄性鸣禽对同种及异域同属物种鸣唱的行为与发声响应，这些实验刺激的声学特征与遗传相似度各不相同。本研究的实验对象为4种新热带区鹪鹩属（Troglodytes）的领域性雄性鸣禽：棕喉鹪鹩（Troglodytes brunneicollis）、科苏梅尔鹪鹩（T. beani）、克拉里昂鹪鹩（T. tanneri）以及索科罗鹪鹩（T. sissonii）。我们的研究结果显示：鸟类会对同种及异域同属物种的回放鸣唱产生响应；声学差异随遗传距离增大而升高；在排除实验对象鸣唱与回放刺激之间的声学相似性影响后，遗传分化可预测鸣禽对回放实验的行为响应强度。综上，本研究结果表明：亲缘关系最远的物种其鸣唱分化程度最高，雄性鹪鹩可感知鸣唱精细结构的差异，且物种间的感知差异反映了物种的演化历史。本研究为习得信号的声学分化及接收者响应在物种识别中的重要性提供了全新视角。