ABSTRACT Temperature fluctuation affects physiology and behaviour in ectotherms. Previous studies revealed that the phonotactic preference of female frogs was affected by temperature fluctuations; however, the corresponding plasticity of peripheral auditory sensitivity is unclear. In the present study, the auditory sensitivity of little torrent frogs (Amolops torrentis) was tested by auditory brainstem responses (ABRs) in both natural warm and cold conditions. The threshold and latency of the ABRs evoked by tone pips ranging from 1.0–7.0 kHz and clicks were compared between these two conditions. The results showed that ABR thresholds were higher and latencies were longer at cold compared to those at warm temperatures for relatively low frequencies (1.8–2.6 kHz), while no significant differences existed at relatively high frequencies (3.0–7.0 kHz). Our previous study showed that the best hearing frequency range of the little torrent frog is 1.6–2.0 kHz, whereas females behaviourally prefer higher frequencies (4.3 kHz). These results indicate that temperature fluctuations in natural habitats can change auditory sensitivity around the best hearing range (1.6–2.0 kHz), while they do not affect the female-preferred frequency range (4.3 kHz). Our results demonstrate that auditory frequency sensitivity exhibits diurnal temperature-dependent plastic changes, which may be adaptive for diurnal reproductive behaviour in this species.

中文翻译：

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小洪流蛙 (Amolops torrentis) 的听觉灵敏度随昼夜温度变化而变化

摘要 温度波动会影响变温动物的生理和行为。先前的研究表明，雌性青蛙的语音偏好受温度波动的影响；然而，外周听觉敏感性的相应可塑性尚不清楚。在本研究中，在自然温暖和寒冷条件下，通过听觉脑干反应 (ABR) 测试了小洪流蛙 (Amolops torrentis) 的听觉敏感性。在这两种条件之间比较了由 1.0-7.0 kHz 范围内的音调和点击引起的 ABR 的阈值和延迟。结果表明，在相对较低的频率（1.8-2.6 kHz）下，与温暖温度下的相比，寒冷时的 ABR 阈值更高且延迟更长，而在相对较高的频率（3.0-7.0 kHz）下没有显着差异。我们之前的研究表明，小洪流蛙的最佳听力频率范围是 1.6-2.0 kHz，而雌性在行为上更喜欢更高的频率 (4.3 kHz)。这些结果表明，自然栖息地的温度波动可以改变最佳听力范围（1.6-2.0 kHz）附近的听觉灵敏度，而不会影响女性首选频率范围（4.3 kHz）。我们的结果表明，听觉频率敏感性表现出昼夜温度依赖性塑性变化，这可能适用于该物种的昼夜繁殖行为。这些结果表明，自然栖息地的温度波动可以改变最佳听力范围（1.6-2.0 kHz）附近的听觉灵敏度，而不会影响女性首选频率范围（4.3 kHz）。我们的结果表明，听觉频率敏感性表现出昼夜温度依赖性塑性变化，这可能适用于该物种的昼夜繁殖行为。这些结果表明，自然栖息地的温度波动可以改变最佳听力范围（1.6-2.0 kHz）附近的听觉灵敏度，而不会影响女性首选频率范围（4.3 kHz）。我们的结果表明，听觉频率敏感性表现出昼夜温度依赖性塑性变化，这可能适用于该物种的昼夜繁殖行为。