Data from: Evidence for hearing loss in amblyopsid cavefishes

The constant darkness of caves and other subterranean habitats imposes sensory constraints that offer a unique opportunity to examine evolution of sensory modalities. Hearing in cavefishes has not been well explored, and here we show that cavefishes in the family Amblyopsidae are not only blind but have also lost a significant portion of their hearing range. Our results showed that cave and surface amblyopsids shared the same audiogram profile at low frequencies but only surface amblyopsids were able to hear frequencies higher than 800 Hz and up to 2 kHz. We measured ambient noise in aquatic cave and surface habitats and found high intensity peaks near 1 kHz for streams underground, suggesting no adaptive advantage in hearing in those frequencies. In addition, cave amblyopsids had lower hair cell densities compared with their surface relative. These traits may have evolved in response to the loud high-frequency background noise found in subterranean pools and streams. This study represents the first report of auditory regression in a subterranean organism.

洞穴及其他地下生境的恒定黑暗环境会对生物施加感官约束，为探究感官模态的演化提供了独特契机。目前学界对盲鳉科（Amblyopsidae）鱼类的听觉研究尚不充分，本研究表明该科的洞穴鱼类不仅完全失明，还丢失了其听觉范围的显著部分。研究结果显示，洞穴生境与地表生境的盲鳉科鱼类在低频段拥有一致的听阈曲线，但仅地表盲鳉能够听到800Hz以上、最高达2kHz的频率。我们测量了水生洞穴及地表生境的环境噪声，发现地下溪流存在接近1kHz的高强度噪声峰值，这表明在该频率段的听觉并无适应性优势。此外，洞穴盲鳉的毛细胞密度低于其地表同类。这些特征可能是为适应地下池塘与溪流中的高强度高频背景噪声演化而来。本研究首次报道了地下生物的听觉退化现象。