1月25日,，一項在線發(fā)表于英國皇家學會《界面》雜志的最新研究,，描述了位于蹄鼻蝠（菊頭蝠科）主鼻葉上方的皺折是如何幫助它們集中聲束并且減少環(huán)境中雜音干擾的。
蹄鼻蝠的鼻子又寬又扁,，雖然看起來可能不是那么漂亮,，卻能在蹄鼻蝠飛行和覓食時幫上大忙。
蹄鼻蝠的鼻子雖然看起來很丑,，卻能幫助它們飛行和覓食,。
蝙蝠利用回聲定位，即通過發(fā)出高聲調的聲音并對反射回來的回聲進行分析來實現移動和獵食,。
研究人員制作了一只蹄鼻蝠的頭部模型和不同的五官模型來探尋這些皺折是如何影響聲音傳遞的,。
他們發(fā)現，當蝙蝠通過鼻子發(fā)出聲音時,，這些皺折能夠減小主鼻葉的尺寸,，由此使聲束的聚焦變緊。雖然這種方式降低了蝙蝠定位獵物的能力,，但同時也減少了棲息地中,，如森林里的雜音的干擾。
這個發(fā)現和之前的研究相矛盾,。此前,，研究人員認為這些皺折使蝙蝠的聲束變寬,，并且可能會幫助它們探知自己離地面有多高。而這項最新研究的作者們認為,，之前研究人員在錯誤的范圍內探測到了回聲頻率改變,，所以才會有如此推論。（生物谷 Bioon.com）
doi:10.1098/rsif.2011.0812
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The furrows of Rhinolophidae revisited
Dieter Vanderelst, Reijniers Jonas and Peremans Herbert
Rhinolophidae, a family of echolocating bats, feature very baroque noseleaves that are assumed to shape their emission beam. Zhuang & Muller (Zhuang & Muller 2006 Phys. Rev. Lett. 97, 218701 (doi:10.1103/PhysRevLett.97.218701); Zhuang & Muller 2007 Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 76(Pt. 1), 051902 (doi:10.1103/PhysRevE.76.051902)) have proposed, based on finite element simulations, that the furrows present in the noseleaves of these bats act as resonance cavities. Using Rhinolophus rouxi as a model species, they reported that a resonance phenomenon causes the main beam to be elongated at a particular narrow frequency range. Virtually filling the furrows reduced the extent of the main lobe. However, the results of Zhuang & Muller are difficult to reconcile with the ecological background of R. rouxi. In this report, we replicate the study of Zhuang & Muller, and extend it in important ways: (i) we take the filtering of the moving pinnae into account, (ii) we use a model of the echolocation task faced by Rhinolophidae to estimate the effect of any alterations to the emission beam on the echolocation performance of the bat, and (iii) we validate our simulations using a physical mock-up of the morphology of R. rouxi. In contrast to Zhuang & Muller, we find the furrows to focus the emitted energy across the whole range of frequencies contained in the calls of R. rouxi (both in simulations and in measurements). Depending on the frequency, the focusing effect of the furrows has different consequences for the estimated echolocation performance. We argue that the furrows act to focus the beam in order to reduce the influence of clutter echoes.
