Data from: Behavioural tuning in a tropical amphibian along an altitudinal gradient

Males of the Coqui treefrog, Eleutherodactylus coqui, produce a distinct two-note 'co-qui' advertisement call from sunset to midnight throughout most of the year. Previous work established that both the spectrotemporal aspects of the call and the frequency of highest inner-ear sensitivity changes with altitude above sea level. These variations are such that the frequency of the emitted co-note closely matches the frequency to which the inner-ear is most sensitive. Given this parallel variation, we expected that the call-evoked behavioural response of male Coqui treefrogs would also show an altitude-dependence, and hypothesized that males would produce their most robust acoustical territorial response to advertisement calls that match calls from their own altitude. We tested this hypothesis in the field by studying the vocal response behaviour of Coquis to playbacks of synthetic, altitude-dependent conspecific calls, and indeed found that the most robust vocal responses were obtained using stimuli closely matching the calls from the same altitude.

科奎树蛙（Coqui treefrog，Eleutherodactylus coqui）的雄性个体，在一年中多数时段的日落至午夜期间，会发出带有独特双音‘co-qui’结构的广告鸣叫（advertisement call）。过往研究已证实，其鸣唱的频谱时域特征与内耳最高敏感频率均会随海拔高度发生改变。此类变异使得鸣唱中‘co’音的频率与该个体内耳最敏感的频率高度匹配。基于这种平行变异现象，我们推测雄性科奎树蛙的鸣唱诱发行为反应同样会呈现海拔依赖性，并提出假说：雄性个体对与自身所处海拔来源的鸣唱相匹配的广告鸣叫，将产生最强的声学领地应答。我们通过野外实验，研究了科奎树蛙对合成的、随海拔变化的同种鸣唱回放刺激的鸣唱应答行为，最终证实当刺激信号与同海拔来源的鸣唱高度匹配时，可获得最强的声学应答反应。