We examined the vocal and non-vocal responses of male cricket frogs (Acris crepitans) to conspecific advertisement calls that had been attenuated or degraded by reducing the depth of amplitude modulation (AM). Both are characteristic of changes to the call as it is transmitted through natural habitats. As stimulus calls became more intense or less degraded, male cricket frogs gradually decreased their call rate and increased the number of call groups and pulse groups in their calls, changes indicative of increased aggressive interactions. At the higher intensities and lower degradation levels, the probability that males would shift to one of two non-vocal behavioral responses, attacking the perceived intruder or ceasing calling and abandoning the call site, gradually increased. The results show that differences in signal attenuation and AM degradation levels are perceived by males and trigger both vocal and non-vocal behavioral responses consistent with their use in evaluating the distance to a challenging male. Furthermore, the results indicate that the male responses are graded, increasing as intensity rises and degradation falls, and hierarchical, with vocal responses preceding behavioral responses over the range of intensities and degradation levels presented.

中文翻译：

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雄性蟋蟀蛙（Acris crepitans）对减弱和退化的广告呼叫的反应

我们检查了雄性蟋蟀蛙 (Acris crepitans) 对通过降低幅度调制 (AM) 深度减弱或降低的同种广告呼叫的声音和非声音反应。两者都是通过自然栖息地传播的呼叫变化的特征。随着刺激呼叫变得更加强烈或减弱，雄性蟋蟀青蛙逐渐降低它们的呼叫率并增加呼叫组和脉冲组的数量，这些变化表明攻击性互动增加。在较高的强度和较低的退化水平下，雄性转变为两种非声音行为反应之一的可能性逐渐增加，即攻击感知到的入侵者或停止呼叫并放弃呼叫站点。结果表明，雄性会感知信号衰减和 AM 退化水平的差异，并触发声音和非声音行为反应，这与它们用于评估与具有挑战性的男性的距离一致。此外，结果表明，男性的反应是分级的，随着强度的上升和退化的下降而增加，并且在呈现的强度和退化水平的范围内，声音反应先于行为反应。