Yin Xiaoyan, Qiu Peiwen, Yang Lili, Müller Rolf
Shandong University-Virginia Tech International Laboratory, 27 Shanda South Road, Jinan, Shandong 250100, People's Republic of China.
Department of Mechanical Engineering, 1075 Life Science Circle, Virginia Tech, Blacksburg, Virginia 24061, USA.
J Acoust Soc Am. 2017 May;141(5):3011. doi: 10.1121/1.4982042.
Horseshoe bats (Rhinolophidae) and the related Old World leaf-nosed bats (Hipposideridae) both show conspicuous pinna motions as part of their biosonar behaviors. In the current work, the kinematics of these motions in one species from each family (Rhinolophus ferrumequinum and Hipposideros armiger) has been analyzed quantitatively using three-dimensional tracking of landmarks placed on the pinna. The pinna motions that were observed in both species fell into two categories: In "rigid rotations" motions the geometry of the pinna was preserved and only its orientation in space was altered. In "open-close motions" the geometry of the pinna was changed which was evident in a change of the distances between the landmark points. A linear discriminant analysis showed that motions from both categories could be separated without any overlap in the analyzed data set. Hence, bats from both species have two separate types of pinna motions with apparently no transitions between them. The deformations associated with open-close pinna motions in Hipposideros armiger were found to be substantially larger compared to the wavelength associated with the largest pulse energy than in Rhinolophus ferrumequinum (137% vs 99%). The role of the two different motions in the biosonar behaviors of the animals remains to be determined.
菊头蝠（菊头蝠科）和与之相关的旧大陆叶鼻蝠（蹄蝠科）在其生物声纳行为中均表现出明显的耳廓运动。在当前研究中，利用放置在耳廓上的标记点进行三维跟踪，对每个科的一个物种（马铁菊头蝠和大蹄蝠）的这些运动的运动学进行了定量分析。在两个物种中观察到的耳廓运动分为两类：在“刚性旋转”运动中，耳廓的几何形状保持不变，只是其在空间中的方向发生了改变。在“开闭运动”中，耳廓的几何形状发生了变化，这在标记点之间的距离变化中很明显。线性判别分析表明，在分析的数据集中，两类运动可以分开，没有任何重叠。因此，两个物种的蝙蝠都有两种不同类型的耳廓运动，它们之间显然没有过渡。与马铁菊头蝠相比，大蹄蝠中与开闭耳廓运动相关的变形相对于与最大脉冲能量相关的波长要大得多（分别为137%和99%）。这两种不同运动在动物生物声纳行为中的作用仍有待确定。
