Wang Tongliang, Yang Jinxia, Lei Jinhong, Huang Jingdeng, Shi Haitao, Wang Jichao
Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences Hainan Normal University Haikou China.
Ecol Evol. 2024 Aug 8;14(8):e70130. doi: 10.1002/ece3.70130. eCollection 2024 Aug.
Sexually dimorphic hearing sensitivity has evolved in many vertebrate species, and the sex with a larger body size typically shows more sensitive hearing. However, generalizing this association is controversial. Research on sexually dimorphic hearing sensitivity contributes to an understanding of auditory sense functions, adaptations, and evolution among species. Therefore, the hypothesized association between body size and hearing needs further validation, especially in specific animal groups. In this study, we assessed hearing sensitivity by measuring auditory brainstem responses (ABRs) in both sexes of 3-year-old Chinese softshell turtles (). In this species, male bodies are larger than those of female, and individuals spend most of their lives in the mud at the bottom of freshwater habitats. We found that for both sexes, the hearing sensitivity bandwidth was 0.2-0.9 kHz. Although males were significantly larger than females, no significant differences in ABR thresholds or latencies were found between males and females at the same stimulus frequency. These results indicate that hearing is only sensitive to low-frequency (typically <0.9 kHz) sound signals and that sexually dimorphic hearing sensitivity is not a trait that has evolved in . Physiological and environmental reasons may account for acoustic communication via low-frequency sound signals and the lack of sexually dimorphic hearing sensitivity in these benthic turtles. The results of this study refine our understanding of the adaptation and evolution of the vertebrate auditory system.
许多脊椎动物物种都进化出了两性异形的听觉敏感性，体型较大的性别通常表现出更敏锐的听觉。然而，将这种关联进行推广存在争议。对两性异形听觉敏感性的研究有助于理解物种间的听觉功能、适应性和进化。因此，体型与听力之间的假设关联需要进一步验证，尤其是在特定动物群体中。在本研究中，我们通过测量3岁中华鳖两性的听觉脑干反应（ABR）来评估听力敏感性。在这个物种中，雄性个体的体型比雌性大，且个体大部分时间生活在淡水栖息地底部的淤泥中。我们发现，两性的听力敏感带宽均为0.2 - 0.9千赫兹。尽管雄性明显比雌性大，但在相同刺激频率下，雄性和雌性之间的ABR阈值或潜伏期没有显著差异。这些结果表明，中华鳖的听力仅对低频（通常<0.9千赫兹）声音信号敏感，且两性异形的听觉敏感性并非中华鳖进化出的一种特征。生理和环境原因可能解释了这些底栖龟类通过低频声音信号进行声学通讯以及缺乏两性异形听觉敏感性的现象。本研究结果完善了我们对脊椎动物听觉系统适应性和进化的理解。
