Zhuang Qiao, Müller Rolf
School of Information Science and Engineering, Shandong University, Shanda Nanlu 27, 250100 Jinan, China.
Phys Rev Lett. 2006 Nov 24;97(21):218701. doi: 10.1103/PhysRevLett.97.218701. Epub 2006 Nov 22.
Horseshoe bats emit their ultrasonic biosonar pulses through nostrils surrounded by intricately shaped protuberances (noseleaves). While these noseleaves have been hypothesized to affect the sonar beam, their physical function has never been analyzed. Using numerical methods, we show that conspicuous furrows in the noseleaf act as resonance cavities shaping the sonar beam. This demonstrates that (a) animals can use resonances in external, half-open cavities to direct sound emissions, (b) structural detail in the faces of bats can have acoustic effects even if it is not adjacent to the emission sites, and (c) specializations in the biosonar system of horseshoe bats allow for differential processing of subbands of the pulse in the acoustic domain.
菊头蝠通过被形状复杂的突出物（鼻叶）环绕的鼻孔发出超声波生物声纳脉冲。虽然这些鼻叶被推测会影响声纳波束，但它们的物理功能从未被分析过。我们通过数值方法表明，鼻叶中明显的沟槽起到了塑造声纳波束的共振腔的作用。这证明了：（a）动物可以利用外部半开放腔体中的共振来引导声音发射；（b）蝙蝠面部的结构细节即使不与发射部位相邻也可能产生声学效应；（c）菊头蝠生物声纳系统的特化使得在声学领域能够对脉冲的子带进行差异处理。
