Yamashita M, Naitoh T, Kashiwagi A, Kondo Y, Wassersug R J
Institute of Space and Astronautical Science, Sagamihara, Kanagawa 229-8510, Japan.
Adv Space Res. 1999;23(12):2083-6. doi: 10.1016/s0273-1177(99)00166-0.
Frogs and toads turn either their heads or bodies opposite to angular accelerations applied around the yaw axis. Thresholds exist for the minimum angular acceleration that induces this vestibulomotor response in individual frogs. These thresholds were recorded for several anuran species that cover a broad range of sizes and life styles. Interspecific variation in the magnitude of the thresholds, which correlated with the ecology and behavior of the species, was documented. Also an allometric relationship was observed between this threshold and body size; the larger the frog, the lower the threshold. In many species, the threshold value for reflexive vestibulomotor responses to angular acceleration was proportional to the -0.4 (+/-0.2) power of body mass. Physical dimensions of the semicircular canals determine, in part, vestibular sensitivity to angular acceleration. Hence changes with growth in the semicircular canals are believed to contribute to the slope of -0.4. The biological significance of this allometry in vestibular responses is discussed and compared to trends in vestibular sensitivity and semicircular canal morphology of other vertebrate classes.
青蛙和蟾蜍会将它们的头部或身体转向与绕偏航轴施加的角加速度相反的方向。对于在个体青蛙中诱发这种前庭运动反应的最小角加速度存在阈值。记录了几种涵盖广泛大小和生活方式的无尾目物种的这些阈值。记录了阈值大小的种间差异，这种差异与物种的生态和行为相关。此外，还观察到该阈值与体型之间的异速生长关系；青蛙越大，阈值越低。在许多物种中，对角加速度的反射性前庭运动反应的阈值与体重的 -0.4（±0.2）次幂成正比。半规管的物理尺寸部分决定了前庭对角加速度的敏感性。因此，人们认为随着生长半规管的变化有助于产生 -0.4 的斜率。讨论了这种前庭反应中异速生长的生物学意义，并与其他脊椎动物类群的前庭敏感性和半规管形态趋势进行了比较。
