Data from: The signal in noise: acoustic information for soundscape orientation in two North American tree frogs

Diverse animals use environmental sounds to orient in ecological soundscapes. Yet, we know little about how acoustic information use drives behavioral decisions to orient. Although the sound generated by frog choruses functions as noise that impairs signal reception by listeners in the aggregation, it can also serve as an informative ecological signal that allows other individuals to orient toward and localize active breeding aggregations. Here, we investigated the acoustic cues that elicit orientation toward the sound of a chorus in green tree frogs (Hyla cinerea) and Cope’s gray tree frogs (Hyla chrysoscelis). We measured phonotaxis behavior of gravid females in response to playbacks of natural choruses and artificial choruses that differed in the types of acoustic information present. Females of both species oriented to natural choruses and to artificial choruses that contained information on the actual timing and temporal structure of individual calls embedded in the sound of the chorus. Artificial choruses with the time-averaged frequency spectrum and amplitude-modulation spectrum of natural choruses, but lacking information on the timing and temporal structure of individual calls, did not elicit positive phonotaxis. Our results indicate that temporal information from individual calls in the din of chorus sounds is necessary to elicit soundscape orientation. Because the temporal structure of individual calls may degrade quickly as the sound of the chorus propagates through the habitat, orientation to breeding choruses based on acoustic information alone may be limited to relatively short distances in these 2 species.多种动物依托环境声响在生态声景中实现定向定位。然而，当前学界对声学信息的利用如何驱动定向行为决策仍缺乏深入认知。尽管蛙类合唱产生的声响会作为干扰噪声，损害集群内接收者的信号感知能力，但这类声响同时也可作为具备信息价值的生态信号，帮助其他个体定位并朝向活跃的繁殖集群移动。本研究以绿雨滨蛙（Hyla cinerea）与科普灰树蛙（Hyla chrysoscelis）为研究对象，探究了可引发个体朝向合唱声定向的声学线索。我们针对两种蛙的怀卵雌性个体，测试了其在自然合唱声与声学信息类型存在差异的人工合唱声回放下的趋声行为。结果显示，两种蛙的怀卵雌性均会朝向自然合唱声，以及嵌入了单只个体鸣叫实际时序与时间结构信息的人工合唱声移动。仅具备自然合唱声的时间平均频谱与调幅频谱，但缺失单只个体鸣叫时序与时间结构信息的人工合唱声，则无法引发正向趋声行为。本研究结果表明，在合唱声的嘈杂背景中，单只个体鸣叫的时间结构信息是引发声景定向的必要条件。由于单只个体鸣叫的时间结构在合唱声于生境中传播的过程中可能快速衰减，仅依托声学信息朝向繁殖合唱声的定向行为，在这两个物种中可能仅能在较近的距离内实现。