Noseleaf Furrows in a Horseshoe Bat Act as Resonance Cavities Shaping the Biosonar Beam

Qiao, Zhuang; Müller, Rolf

doi:10.1103/physrevlett.97.218701

Cited by 77 publications

(71 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Therefore, it might be questioned whether the reported effects are functionally relevant to the bat. As, neither of the papers published by Zhuang & Muller [3,4] contain quantitative data about the changes in sound pressure caused by filling the furrows it is difficult to interpret the possible relevance of the presented changes to the emission beam pattern.…”

Section: Discussionmentioning

confidence: 99%

“…First, in addition to the noseleaf, we also include the effects of the pinnae into the analysis thereby removing an important limitation of the study by Zhuang & Muller [3,4] and Schnitzler & Grinnell [2]. Indeed, we have demonstrated earlier that the noseleaf effects on the emission beam are attenuated when considering the spatial sensitivity of the complete echolocation system [5].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The furrows of Rhinolophidae revisited

Vanderelst

Reijniers

Peremans

2012

J. R. Soc. Interface.

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The furrows of Rhinolophidae revisited

Vanderelst

Reijniers

Peremans

2012

J. R. Soc. Interface.

View full text Add to dashboard Cite

show abstract

“…The importance of a narrow beam at comparatively low frequencies is also consistent with the rudimentary nature of the noseleaf lancet and particularly its furrows in Bourret's horseshoe bat. The furrows of the lancet have been shown to act as resonance cavities that widen the biosonar beam at low frequencies of the biosonar pulse in other horseshoe bat species [21]. Such a function would contradict the effect of the long sella in Bourret's horseshoe bat and may be precluded anyway by strong shadowing from the large sella.…”

Section: H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Acoustic Effects Accurately Predict an Extreme Case of Biological Morphology

2009

Self Cite

View full text Add to dashboard Cite

The biosonar system of bats utilizes physical baffle shapes around the sites of ultrasound emission for diffraction-based beam forming. Among these shapes, some extreme cases have evolved that include a long noseleaf protrusion (sella) in a species of horseshoe bat. We have evaluated the acoustic cost function associated with sella length with a computational physics approach and found that the extreme length can be predicted accurately from a fiducial point on this function. This suggests that some extreme cases of biological morphology can be explained from their physical function alone.

show abstract

“…These results imply that the noseleaf is likely to focus the beam pattern of nasal emitters. In addition, numerical computations based on the 3D structure of the emitter portion of bats have demonstrated that the noseleaf affects the directivity pattern of the emitted pulse (Zhuang and Müller, 2006;Zhuang and Müller, 2007;Vanderelst et al, 2010;Vanderelst et al, 2011). In the present study, horizontal beam width of R. ferrumequinum nippon was ±22±5deg, and was expanded to ±36±7deg in the terminal phase.…”

Section: How Do the Bats Change Their Beam Pattern?mentioning

confidence: 66%

Adaptive beam-width control of echolocation sounds by CF–FM bats,Rhinolophus ferrumequinum nippon, during prey-capture flight

Matsuta

Hiryu

Fujioka

et al. 2013

Journal of Experimental Biology

View full text Add to dashboard Cite

SUMMARYThe echolocation sounds of Japanese CF-FM bats (Rhinolophus ferrumequinum nippon) were measured while the bats pursued a moth (Goniocraspidum pryeri) in a flight chamber. Using a 31-channel microphone array system, we investigated how CF-FM bats adjust pulse direction and beam width according to prey position. During the search and approach phases, the horizontal and vertical beam widths were ±22±5 and ±13±5deg, respectively. When bats entered the terminal phase approximately 1m from a moth, distinctive evasive flight by G. pryeri was sometimes observed. Simultaneously, the bats broadened the beam widths of some emissions in both the horizontal (44% of emitted echolocation pulses) and vertical planes (71%). The expanded beam widths were ±36±7deg (horizontal) and ±30±9deg (vertical). When moths began evasive flight, the tracking accuracy decreased compared with that during the approach phase. However, in 97% of emissions during the terminal phase, the beam width was wider than the misalignment (the angular difference between the pulse and target directions). These findings indicate that bats actively adjust their beam width to retain the moving target within a spatial echolocation window during the final capture stages.

show abstract

Noseleaf Furrows in a Horseshoe Bat Act as Resonance Cavities Shaping the Biosonar Beam

Cited by 77 publications

References 23 publications

The furrows of Rhinolophidae revisited

The furrows of Rhinolophidae revisited

Acoustic Effects Accurately Predict an Extreme Case of Biological Morphology

Adaptive beam-width control of echolocation sounds by CF–FM bats,Rhinolophus ferrumequinum nippon, during prey-capture flight

Contact Info

Product

Resources

About