蛙类的繁殖行为具有明显的季节性。春季,雄性进入繁殖季节,开始大声鸣叫,以争夺配偶和领地。此时,雌性的听觉系统需要处理各种复杂的鸣声信号,例如,雌性仙琴蛙可根据鸣声的结构特点判断鸣声是否从洞穴中发出;冬季,蛙类进入冬眠,无需处理复杂的声音信号,此时最重要的是节约能量过冬。由此可推测:蛙类可能在冬季降低听觉系统的敏感性,以节约能量过冬,而在春季提高听觉系统的敏感性,处理各种复杂的声音信号。然而,关于蛙类外周听觉系统是否具有季节可塑性尚无确切证据。
日前,PLoS ONE在线发表了成都生物所唐业忠课题组崔建国等人的最新研究成果。研究人员检测了仙琴蛙(Emei music frog, Babina daunchina)在不同季节的听觉脑干反应(Auditory Brainstem Responses,ABRs)。结果显示,在1-6KHz的范围内,非繁殖季节的听觉脑干反应阈值显著高于繁殖季节,反应时间显著长于繁殖季节,说明非繁殖季节的听觉敏感性显著低于繁殖季节。这些结果表明蛙类外周听觉系统具有季节可塑性,以适应蛙类的季节性繁殖。论文的第一作者为博士研究生张典。(生物谷Bioon.com)
doi:10.1371/journal.pone.0045792
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Plasticity of Peripheral Auditory Frequency Sensitivity in Emei Music Frog
Dian Zhang, Jianguo Cui, Yezhong Tang
In anurans reproductive behavior is strongly seasonal. During the spring, frogs emerge from hibernation and males vocalize for mating or advertising territories. Female frogs have the ability to evaluate the quality of the males' resources on the basis of these vocalizations. Although studies revealed that central single torus semicircularis neurons in frogs exhibit season plasticity, the plasticity of peripheral auditory sensitivity in frog is unknown. In this study the seasonally plasticity of peripheral auditory sensitivity was test in the Emei music frog Babina daunchina, by comparing thresholds and latencies of auditory brainstem responses (ABRs) evoked by tone pips and clicks in the reproductive and non-reproductive seasons. The results show that both ABR thresholds and latency differ significantly between the reproductive and non-reproductive seasons. The thresholds of tone pip evoked ABRs in the non-reproductive season increased significantly about 10 dB than those in the reproductive season for frequencies from 1 KHz to 6 KHz. ABR latencies to waveform valley values for tone pips for the same frequencies using appropriate threshold stimulus levels are longer than those in the reproductive season for frequencies from 1.5 to 6 KHz range, although from 0.2 to 1.5 KHz range it is shorter in the non-reproductive season. These results demonstrated that peripheral auditory frequency sensitivity exhibits seasonal plasticity changes which may be adaptive to seasonal reproductive behavior in frogs.