scholarly journals The frugivorous bat Carollia perspicillata dynamically changes echolocation parameters in response to acoustic playback

2021 ◽  
Vol 224 (6) ◽  
pp. jeb234245
Author(s):  
M. Jerome Beetz ◽  
Manfred Kössl ◽  
Julio C. Hechavarría
Keyword(s):  
Signal Extraction ◽  
Vocal Behavior ◽  
Noisy Environments ◽  
Carollia Perspicillata ◽  
Insectivorous Bats ◽  
Echolocation Calls ◽  
Individual Level ◽  
Acoustic Interference ◽  
Presence And Absence ◽  
Enriched Environments

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.

scholarly journals Bats dynamically change echolocation parameters in response to acoustic playback

2019 ◽  
Author(s):  
M. Jerome Beetz ◽  
Manfred Kossl ◽  
Julio C. Hechavarria
Keyword(s):  
Precise Definition ◽  
Signal Extraction ◽  
Noisy Environments ◽  
Orientation Behavior ◽  
Carollia Perspicillata ◽  
Enriched Environments ◽  
Definition Of

Animals extract behaviorally relevant signals from 'noisy' environments. To investigate signal extraction, echolocating provides a rich system testbed. For orientation, bats broadcast calls and assign each echo to the corresponding call. When orienting in acoustically enriched environments or when approaching targets, bats change their spectro-temporal call design. Thus, to assess call adjustments that are exclusively meant to facilitate signal extraction in 'noisy' environments, it is necessary to control for distance-dependent call changes. By swinging bats in a pendulum, we tested the influence of acoustic playback on the echolocation behavior of Carollia perspicillata. This paradigm evokes reproducible orientation behavior and allows a precise definition of the influence of the acoustic context. Our results show that bats dynamically switch between different adaptations to cope with sound-based navigation in acoustically contaminated environments. These dynamics of echolocation behavior may explain the large variety of adaptations that have been reported in the bat literature.

ALTERNATION OF ECHOLOCATION CALLS IN 5 SPECIES OF AERIAL-FEEDING INSECTIVOROUS BATS FROM MALAYSIA

2003 ◽  
Vol 84 (1) ◽  
pp. 205-215 ◽  
Author(s):  
Tigga Kingston ◽  
Gareth Jones ◽  
Zubaid Akbar ◽  
Thomas H. Kunz
Keyword(s):  
Insectivorous Bats ◽  
Echolocation Calls

Echolocation and feeding behaviour of Taphozous mauritianus (Chiroptera: Emballonuridae)

1980 ◽  
Vol 58 (10) ◽  
pp. 1774-1777 ◽  
Author(s):  
M. B. Fenton ◽  
G. P. Bell ◽  
D. W. Thomas
Keyword(s):  
Long Range ◽  
Feeding Behaviour ◽  
Second Harmonic ◽  
Feeding Strategy ◽  
Rapid Rise ◽  
Constant Frequency ◽  
Insectivorous Bats ◽  
Sound Energy ◽  
Echolocation Calls ◽  
Human Ear

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.

Anti-bat flight activity in sound-producing versus silent moths

2008 ◽  
Vol 86 (6) ◽  
pp. 582-587 ◽  
Author(s):  
John M. Ratcliffe ◽  
Amanda R. Soutar ◽  
Katherine E. Muma ◽  
Cassandra Guignion ◽  
James H. Fullard
Keyword(s):  
Flight Time ◽  
Flight Activity ◽  
Echolocation Calls ◽  
Successful Reproduction ◽  
Tiger Moth ◽  
Moth Species ◽  
Presence And Absence ◽  
Tiger Moths ◽  
Palatable Species

The ultrasonic clicks produced by some tiger moths — all of which possess bat-detecting ears — are effective acoustic aposematic or mimetic signals, conferring protection against aerial hawking bats. Clicks are produced in response to bat echolocation calls. Palatable, silent non-tiger-moth species with bat-detecting ears fly away from distant bats and effect erratic flight maneuvers or stop flying in response to the calls of bats nearby. These flight responses are also an effective defense. We tested the hypotheses that sound-producing tiger moths (i) do not exhibit the reduction in flight time typical of silent, palatable moth species when presented with ultrasound simulating bat echolocation calls and (ii) exhibit more flight activity than silent, palatable species both in the presence and absence of ultrasound. We found that sound-producing tiger moths did not significantly reduce flight activity to bat-like sounds and that silent tiger moths and other noctuoid species did. We also found that sound-producing tiger moths flew significantly more than did silent species in both the presence and the absence of ultrasound. The benefits of acoustic aposematism may allow sound producers to spend more time aloft than silent species and thereby improve their chances of successful reproduction.

The echolocation calls of the spotted bat Euderma maculatum are relatively inaudible to moths

1997 ◽  
Vol 200 (1) ◽  
pp. 129-137 ◽  
Author(s):  
J Fullard ◽  
J Dawson
Keyword(s):  
Eptesicus Fuscus ◽  
Auditory Threshold ◽  
Western Canada ◽  
Acoustic Characteristics ◽  
Insectivorous Bats ◽  
Echolocation Calls ◽  
In The Wild ◽  
A Site ◽  
Approach Phase

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.

The echolocation calls of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats as adaptations for long- versus short-range foraging strategies and the consequences for prey selection

1986 ◽  
Vol 64 (12) ◽  
pp. 2700-2705 ◽  
Author(s):  
Robert M. R. Barclay
Keyword(s):  
Prey Selection ◽  
Foraging Strategy ◽  
Prey Detection ◽  
Constant Frequency ◽  
Insectivorous Bats ◽  
Lasiurus Cinereus ◽  
Echolocation Calls ◽  
Close Range ◽  
Search Approach ◽  
Lasionycteris Noctivagans

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.

Intraspecific Variation in the Echolocation Calls of Two Species of Insectivorous Bats

1989 ◽  
Vol 70 (2) ◽  
pp. 426-428 ◽  
Author(s):  
R. M. Brigham ◽  
J. E. Cebek ◽  
M. B. C. Hickey
Keyword(s):  
Intraspecific Variation ◽  
Insectivorous Bats ◽  
Echolocation Calls

Habitat use by foraging insectivorous bats

1987 ◽  
Vol 65 (2) ◽  
pp. 284-288 ◽  
Author(s):  
C. L. Furlonger ◽  
H. J. Dewar ◽  
M. B. Fenton
Keyword(s):  
Habitat Use ◽  
Rural Areas ◽  
Urban Areas ◽  
Foraging Activity ◽  
Insectivorous Bats ◽  
Widespread Species ◽  
Lasiurus Borealis ◽  
Lasiurus Cinereus ◽  
Echolocation Calls ◽  
Study Sites

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.

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
Keyword(s):  
Insectivorous Bats ◽  
Echolocation Calls
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