Doppler-shift compensation in insect-catching horseshoe bats

1982 ◽  
Vol 69 (4) ◽  
pp. 193-194 ◽  
Author(s):  
M. Trappe ◽  
H. -U. Schnitzler
Keyword(s):  
Doppler Shift ◽  
Horseshoe Bats

Doppler-shift compensation behavior in horseshoe bats revisited: auditory feedback controls both a decrease and an increase in call frequency

2002 ◽  
Vol 205 (11) ◽  
pp. 1607-1616 ◽  
Author(s):  
Walter Metzner ◽  
Shuyi Zhang ◽  
Michael Smotherman
Keyword(s):  
Feedback Control ◽  
Doppler Shift ◽  
Auditory Feedback ◽  
Control Mechanism ◽  
Echolocation Calls ◽  
Doppler Shifts ◽  
Compensation Behavior ◽  
Vocal Control ◽  
Inhibitory Feedback ◽  
Horseshoe Bats

SUMMARY Among mammals, echolocation in bats illustrates the vital role of proper audio-vocal feedback control particularly well. Bats adjust the temporal,spectral and intensity parameters of their echolocation calls depending on the characteristics of the returning echo signal. The mechanism of audio-vocal integration in both mammals and birds is, however, still largely unknown. Here, we present behavioral evidence suggesting a novel audio-vocal control mechanism in echolocating horseshoe bats (Rhinolophus ferrumequinum). These bats compensate for even subtle frequency shifts in the echo caused by flight-induced Doppler effects by adjusting the frequency of their echolocation calls. Under natural conditions, when approaching background targets, the bats usually encounter only positive Doppler shifts. Hence, we commonly believed that, during this Doppler-shift compensation behavior,horseshoe bats use auditory feedback to compensate only for these increases in echo frequency (=positive shifts) by actively lowering their call frequency below the resting frequency (the call frequency emitted when not flying and not experiencing Doppler shifts). Re-investigation of the Doppler-shift compensation behavior, however, shows that decreasing echo frequencies(=negative shifts) are involved as well: auditory feedback from frequencies below the resting frequency, when presented at similar suprathreshold intensity levels as higher echo frequencies, cause the bat's call frequency to increase above the resting frequency. However, compensation for negative shifts is less complete than for positive shifts (22% versus 95%),probably because of biomechanical restrictions in the larynx of bats. Therefore, Doppler-shift compensation behavior involves a quite different neural substrate and audio-vocal control mechanism from those previously assumed. The behavioral results are no longer consistent with solely inhibitory feedback originating from frequencies above the resting frequency. Instead, we propose that auditory feedback follows an antagonistic push/pull principle, with inhibitory feedback lowering and excitatory feedback increasing call frequencies. While the behavioral significance of an active compensation for echo frequencies below RF remains unclear, these behavioral results are crucial for determining the neural implementation of audio-vocal feedback control in horseshoe bats and possibly in mammals in general.

Effects of Echo Intensity on Doppler-Shift Compensation Behavior in Horseshoe Bats

2003 ◽  
Vol 89 (2) ◽  
pp. 814-821 ◽  
Author(s):  
Michael Smotherman ◽  
Walter Metzner
Keyword(s):  
Doppler Shift ◽  
Reference Frequency ◽  
Frequency Compensation ◽  
Echo Intensity ◽  
Experimental Conditions ◽  
Emission Frequency ◽  
Delay Duration ◽  
Compensation Behavior ◽  
Systematic Shift ◽  
Horseshoe Bats

Echolocating horseshoe bats respond to flight-speed induced shifts in echo frequency by adjusting the frequency of subsequent calls. Under natural conditions, Doppler effects may force the frequency of a returning echo several kilohertz above the original emission frequency. By lowering subsequent call frequencies, the bat can return echo frequencies to within a narrow spectral bandwidth to which its highly specialized auditory system is most sensitive. While Doppler-shift compensation (DSC) behavior specifically refers to frequency compensation, other parameters of the returning echo, such as delay, duration, and interaural time and intensity differences have been shown to influence DSC performance. Understanding the nature of these influences has already led to a better appreciation of the neurophysiology of DSC. Here we provide a quantitative analysis of the effects of a prominent feature of the returning echo, its intensity, on DSC performance in horseshoe bats. Although DSC performance generally tolerates echo attenuation up to approximately 40 dB relative to the outgoing emission intensity, a systematic decline in DSC performance can be observed over this range. Generally, the effects of echo attenuation are characterized by a reduction in 1) the overall amount of compensation relative to the size of the shift in echo frequency and 2) the rate at which the bat responds to perceived echo shifts. These effects appear to be the consequence of a systematic shift in the range of echo frequencies capable of inducing DSC behavior. In particular, the reference frequency (the minimum shift in echo frequency that will elicit DSC behavior) appears to be highly sensitive to echo intensity. Every 10-dB reduction in echo intensity shifts the reference upward nearly 250 Hz. Our results indicate that, even at the highest intensity levels, relatively minor changes in echo intensity critically influence frequency compensation during normal DSC. We conclude with a discussion of how these results might impact echolocation behavior of horseshoe bats under natural and experimental conditions.

Doppler shift effect on infrared band models

1989 ◽  
Author(s):  
J. DRAKES ◽  
R. HIERS ◽  
R. REED
Keyword(s):  
Doppler Shift ◽  
Infrared Band ◽  
Shift Effect

The Behaviour and Vocalisations of Captive Geoffroy's Horseshoe Bats, Rhinolophus clivosus (Chiroptera: Rhinolophidae)

2019 ◽  
Vol 20 (2) ◽  
pp. 439
Author(s):  
Hana Petersen ◽  
Nikita Finger ◽  
Anna Bastian ◽  
David Jacobs
Keyword(s):  
Horseshoe Bats

Portal Blood Flow as Measured by the Doppler Shift Technique in Sheep Fed Chopped Forages

1975 ◽  
Vol 41 (2) ◽  
pp. 596-600 ◽  
Author(s):  
L. R. Prewitt ◽  
D. R. Jacobson ◽  
R. W. Hemken ◽  
R. H. Hatton
Keyword(s):  
Blood Flow ◽  
Doppler Shift ◽  
Portal Blood Flow ◽  
Portal Blood ◽  
Shift Technique
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