Recognition of Species of Insectivorous Bats by Their Echolocation Calls

1981 ◽  
Vol 62 (2) ◽  
pp. 233-243 ◽  
Author(s):  
M. B. Fenton ◽  
G. P. Bell
2003 ◽  
Vol 84 (1) ◽  
pp. 205-215 ◽  
Author(s):  
Tigga Kingston ◽  
Gareth Jones ◽  
Zubaid Akbar ◽  
Thomas H. Kunz

1980 ◽  
Vol 58 (10) ◽  
pp. 1774-1777 ◽  
Author(s):  
M. B. Fenton ◽  
G. P. Bell ◽  
D. W. Thomas

Observations of free-flying bats in the field in Zimbabwe indicated that Taphozous mauritianus uses multiharmonic constant frequency (CF) search calls followed by multiharmonic approach and terminal calls that combine shallow and steep frequency modulated (FM) sweeps during approaches to targets. The three phases of calls all have rapid rise times to full amplitude, and most of the sound energy is in the second harmonic; the fundamental is usually present (11–13 kHz), making the calls clearly audible to the unaided human ear. This combination of characters, but particularly the CF search calls, serves to distinguish these echolocation calls from those of other insectivorous bats. One light-tagged individual hunting insects reacted to targets at distances of about 3 m, suggesting a long-range feeding strategy.


1997 ◽  
Vol 200 (1) ◽  
pp. 129-137 ◽  
Author(s):  
J Fullard ◽  
J Dawson

Previous studies of the spotted bat Euderma maculatum have demonstrated that this bat emits echolocation calls that are lower in frequency, shorter in duration and fainter in intensity compared with those of most other insectivorous bats, acoustic characteristics which should render it less conspicuous to eared moths. We tested this prediction by monitoring electrophysiologically the ears of sympatric noctuoid (noctuid, arctiid and notodontid) moths in a site in western Canada. Auditory threshold curves demonstrate that most of the moths tested are less responsive to the calls of Eu. maculatum than to those of another sympatric bat, Eptesicus fuscus. Playbacks to moth ears of pre-recorded search- and approach-phase echolocation calls of Eu. maculatum and Ep. fuscus further demonstrate that the calls of Eu. maculatum are poorly detectable to moths and, in some cases, completely inaudible. We estimate that, in the wild, an average noctuoid moth would detect the calls of Eu. maculatum at distances of less than 1 m as opposed to the calls of Ep. fuscus which should be first heard at distances of 20­25 m. Although most moths are unable to adequately hear Eu. maculatum, the observation that two individuals possessed ears sensitive to this bat's calls suggests the existence of auditory pre-adaptation to this type of echolocation.


1986 ◽  
Vol 64 (12) ◽  
pp. 2700-2705 ◽  
Author(s):  
Robert M. R. Barclay

Amongst aerial-feeding insectivorous bats, differences in the design of echolocation calls appear to be associated with differences in foraging strategy. Recordings and observations of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats in Manitoba, Canada, support such an association. Lasionycteris noctivagans use multiharmonic search–approach calls with an initial frequency sweep and a constant frequency tail. Such calls are suited for bats foraging in the open but near obstacles, and pursuing prey detected at relatively close range. This is the foraging strategy employed by this relatively slow, manoeuverable species. Lasiurus cinereus employ single harmonic search–approach calls that are low (20–17 kHz), essentially constant frequency signals. Calls of this design are suited for long-range target detection in open air situations, the foraging strategy used by L. cinereus. Differences in call design may explain dietary differences between the two species. Lasiurus cinereus consistently prey on large insects. The low, constant frequency design of their calls means that small insects are detectable only at close range and are thus difficult for this fast-dying bat to catch. The broad-band calls used by L. noctivagans do not restrict prey detection and these bats prey on a wider range of insects. Similar restrictions on prey detection, caused by echolocation call specializations, may be important in producing what might otherwise be considered active prey selection by some insectivorous bats.


1989 ◽  
Vol 70 (2) ◽  
pp. 426-428 ◽  
Author(s):  
R. M. Brigham ◽  
J. E. Cebek ◽  
M. B. C. Hickey

1987 ◽  
Vol 65 (2) ◽  
pp. 284-288 ◽  
Author(s):  
C. L. Furlonger ◽  
H. J. Dewar ◽  
M. B. Fenton

We monitored echolocation calls to measure the activity of insectivorous bats at study sites in southwestern Ontario during the summer of 1985, relying on feeding buzzes to identify foraging activity. Eptesicus fuscus was the most common and widespread species in the area, while Lasiurus cinereus and Lasiurus borealis were widespread. Species in the genus Myotis were more restricted in their distribution, being more common in an area with potential hibernacula. None of the species foraged exclusively in one habitat and all species exploited concentrations of insects around lights. Only E. fuscus made significant use of lights as foraging sites in urban areas while in town and rural areas all of the species foraged around lights.


2021 ◽  
Vol 224 (6) ◽  
pp. jeb234245
Author(s):  
M. Jerome Beetz ◽  
Manfred Kössl ◽  
Julio C. Hechavarría

ABSTRACTAnimals extract behaviorally relevant signals from ‘noisy’ environments. Echolocation behavior provides a rich system testbed for investigating signal extraction. When echolocating in acoustically enriched environments, bats show many adaptations that are believed to facilitate signal extraction. Most studies to date focused on describing adaptations in insectivorous bats while frugivorous bats have rarely been tested. Here, we characterize how the frugivorous bat Carollia perspicillata adapts its echolocation behavior in response to acoustic playback. Since bats not only adapt their echolocation calls in response to acoustic interference but also with respect to target distances, we swung bats on a pendulum to control for distance-dependent call changes. Forward swings evoked consistent echolocation behavior similar to approach flights. By comparing the echolocation behavior recorded in the presence and absence of acoustic playback, we could precisely define the influence of the acoustic context on the bats' vocal behavior. Our results show that C. perspicillata decrease the terminal peak frequencies of their calls when echolocating in the presence of acoustic playback. When considering the results at an individual level, it became clear that each bat dynamically adjusts different echolocation parameters across and even within experimental days. Utilizing such dynamics, bats create unique echolocation streams that could facilitate signal extraction in noisy environments.


1999 ◽  
Vol 247 (3) ◽  
pp. 381-393 ◽  
Author(s):  
W. Bogdanowicz ◽  
M. B. Fenton ◽  
K. Daleszczyk

1993 ◽  
Vol 178 (1) ◽  
pp. 173-189 ◽  
Author(s):  
P. A. Faure ◽  
J. H. Fullard ◽  
J. W. Dawson

This study empirically tests the prediction that the echolocation calls of gleaning insectivorous bats (short duration, high frequency, low intensity) are acoustically mismatched to the ears of noctuid moths and are less detectable than those of aerially hawking bats. We recorded auditory receptor cell action potentials elicited in underwing moths (Catocala spp.) by echolocation calls emitted during gleaning attacks by Myotis septentrionalis (the northern long-eared bat) and during flights by the aerial hawker Myotis lucifugus (the little brown bat). The moth ear responds inconsistently and with fewer action potentials to the echolocation calls emitted by the gleaner, a situation that worsened when the moth's ear was covered by its wing (mimicking a moth resting on a surface). Calls emitted by the aerial-hawking bat elicited a significantly stronger spiking response from the moth ear. Moths with their ears covered by their wings maintained their relative hearing sensitivity at their best frequency range, the range used by most aerial insectivorous bats, but showed a pronounced deafness in the frequency range typically employed by gleaning bats. Our results (1) support the prediction that the echolocation calls of gleaners are acoustically inconspicuous to the ears of moths (and presumably other nocturnal tympanate insects), leaving the moths particularly vulnerable to predation, and (2) suggest that gleaners gain a foraging advantage against eared prey.


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