The echolocation of flying insects by bats

Griffin, Donald R.; Webster, Frederic A.; Michael, Charles R.

doi:10.1016/0003-3472(60)90022-1

Cited by 588 publications

(372 citation statements)

References 6 publications

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“…perforatus, as they searched, pursued and captured flying insects. Both species produced the full suite of echolocation calls (Griffin et al 1960), including search phase calls ( figure 1a,b), approach phase calls and feeding buzzes ( figure 1c(i)). For T. teniotis we occasionally observed mixtures of echolocation calls and distinct lowfrequency social calls (sinusoidally FM); in some multibat situations (but never when bats flew alone) we also observed 'social buzzes' that differed from feeding buzzes ( figure 1c(ii)).…”

Section: Resultsmentioning

confidence: 99%

“…Echolocating microchiropteran bats use tonal sonar calls, extracting information about target distance, direction and nature by comparing the original signal with returning echoes (Griffin 1958). When approaching a target, echolocating bats move from 'search phase' calls, characterized by stable call parameters and long intercall intervals, to approach, and terminal phases (feeding buzz) involving dramatic shortening of call durations and intercall intervals (Griffin et al 1960;Schnitzler & Kalko 2001). Some species produce echolocation calls at a high duty cycle (call duration/intercall interval), dominated by a narrow constant frequency (CF) band, whereas others echolocate at a low duty cycle, with calls dominated by frequencymodulated (FM) signals of varying bandwidth (Fenton et al 1995;Schnitzler & Kalko 2001).…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of jamming avoidance in echolocating bats

Ulanovsky

Fenton²,

Tsoar

et al. 2004

Proc. R. Soc. Lond. B

156

131

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Animals using active sensing systems such as echolocation or electrolocation may experience interference from the signals of neighbouring conspecifics, which can be offset by a jamming avoidance response (JAR). Here, we report JAR in one echolocating bat (Tadarida teniotis: Molossidae) but not in another (Taphozous perforatus: Emballonuridae) when both flew and foraged with conspecifics. In T. teniotis, JAR consisted of shifts in the dominant frequencies of echolocation calls, enhancing differences among individuals. Larger spectral overlap of signals elicited stronger JAR. Tadarida teniotis showed two types of JAR: (i) for distant conspecifics: a symmetric JAR, with lower-and higher-frequency bats shifting their frequencies downwards and upwards, respectively, on average by the same amount; and (ii) for closer conspecifics: an asymmetric JAR, with only the upper-frequency bat shifting its frequency upwards. In comparison, 'wave-type' weakly electric fishes also shift frequencies of discharges in a JAR, but unlike T. teniotis, the shifts are either symmetric in some species or asymmetric in others. We hypothesize that symmetric JAR in T. teniotis serves to avoid jamming and improve echolocation, whereas asymmetric JAR may aid communication by helping to identify and locate conspecifics, thus minimizing chances of mid-air collisions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamics of jamming avoidance in echolocating bats

Ulanovsky

Fenton²,

Tsoar

et al. 2004

Proc. R. Soc. Lond. B

156

131

View full text Add to dashboard Cite

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“…Ambiguous calls were classified as such. Feeding buzzes (high echolocation pulse repetition rates associated with attacks on prey, Griffin et al 1960), were also counted as a measure of foraging activity (O'Donnell 2000b).…”

Section: Indexing Bat Activitymentioning

confidence: 99%

Habitat use and nocturnal activity of lesser short‐tailed bats(Mystacina tuberculata)in comparison with long‐tailed bats(Chalinolobus tuberculatus)in temperate rainforest

O’Donnell¹,

Christie²,

Simpson³

2006

New Zealand Journal of Zoology

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Habitat use and nocturnal activity patterns of the threatened lesser short-tailed bat (Mystacina tuberculata) were sampled during late spring and early summer using automatic bat detector units in temperate beech (Nothofagus) rainforest in Fiordland, New Zealand. Detector units recorded the number of bats passing per hour as an index of activity. Habitat use patterns were compared with longtailed bats (Chalinolobus tuberculatus) sampled concurrently. Activity levels in lesser short-tailed bats varied significantly among five habitat types and amongst hours of the night. Of the total activity recorded, most passes (82.6% of n = 657 bat passes) were in red beech forest >200 m from the forest edge; 13.7% were in silver beech within 100 m of forest edges, 2.6% were along roads through forest, 0.9% were on the forest-grassland edge, and 0.2% were in the open grassland. Lesser short-tailed bats were active throughout the night but especially at dawn and dusk. There was no correlation between levels of activity by lesser short-tailed bats and overnight minimum or dusk temperatures. Patterns of habitat use and activity in long-tailed bats were significantly different from those of lesser short-tailed bats. Z06009; Online publication date 19 April 2006 Received 20 December 2005; accepted 3 April 2006Of the total activity recorded, most (56.0% of n = 2929 bat passes) was along forest-grassland edges; 15.7% of passes were in open grassland, 13.1% were along roads through forest, 11.0% were in silver beech forest within 100 m of forest edges, and 4.2% within red beech forest. The implications of these findings for conservation and for improving survey techniques are discussed. For example, lack of use of open and edge habitats by lesser short-tailed bats suggests they would not adapt to highly fragmented and cleared forest habitats. The two species of New Zealand bat used available habitats differently while inhabiting the same sites. Therefore, a range of habitats, including forest interior, forest edges and grasslands, are required to sustain both species within reserves and management areas. Surveys for lesser short-tailed bats should focus on mature forest stands >200 m into the forest to maximise the chance of encountering this species, whereas surveys for long-tailed bats would best focus on forest edges.

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“…Bats modify echolocation call parameters such as duration, repetition rate, and intensity in response to obstacles and habitat (9,10). In general, aerial insectivorous bats increase bandwidth and repetition rate and decrease duration of their calls as they close in on prey during a pursuit sequence (11).…”

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confidence: 99%

Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit

Jakobsen

Surlykke

2010

Proc. Natl. Acad. Sci. U.S.A.

123

149

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Animals using sound for communication emit directional signals, focusing most acoustic energy in one direction. Echolocating bats are listening for soft echoes from insects. Therefore, a directional biosonar sound beam greatly increases detection probability in the forward direction and decreases off-axis echoes. However, high directionality has context-specific disadvantages: at close range the detection space will be vastly reduced, making a broad beam favorable. Hence, a flexible system would be very advantageous. We investigated whether bats can dynamically change directionality of their biosonar during aerial pursuit of insects. We trained five Myotis daubentonii and one Eptesicus serotinus to capture tethered mealworms and recorded their echolocation signals with a multimicrophone array. The results show that the bats broaden the echolocation beam drastically in the terminal phase of prey pursuit. M. daubentonii increased the half-amplitude angle from approximately 40°to approximately 90°horizontally and from approximately 45°to more than 90°vertically. The increase in beam width is achieved by lowering the frequency by roughly one octave from approximately 55 kHz to approximately 27.5 kHz. The E. serotinus showed beam broadening remarkably similar to that of M. daubentonii. Our results demonstrate dynamic control of beam width in both species. Hence, we propose directionality as an explanation for the frequency decrease observed in the buzz of aerial hawking vespertilionid bats. We predict that future studies will reveal dynamic control of beam width in a broad range of acoustically communicating animals.A coustic communication plays a major role for conspecific and predator/prey interactions in many animals. Features of emitted sounds, such as time-frequency structure, intensity, and directionality, are central for communication range and direction. Flexibility in acoustic behavior allows for adaptive changes in sound signals to the constraints of a variety of contexts and purposes (1, 2). Directionality defines the angle of attention and is consequently a spatial filter for communication. Thus, directionality is as significant as other acoustic features, but as a result of the methodological challenge in measuring it, directionality has only very rarely been studied in the field (3-6), and almost nothing is known about possible dynamic changes in directionality in response to behavioral tasks. Bats are ideal animals in which to study dynamic changes in directionality, as recording their highintensity echolocation calls allow us to infer, from the bat's adaptive vocal changes to the changing context, which acoustic elements are important for perception through sound.Echolocating bats can hunt and navigate without light, emitting short high-frequency sound pulses to determine the direction, distance, and features of objects in the environment from binaural cues, arrival time, amplitude, and spectrum of sonar reflections (7,8). Bats modify echolocation call parameters such as duration, repetition rate, and...

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The echolocation of flying insects by bats

Cited by 588 publications

References 6 publications

Dynamics of jamming avoidance in echolocating bats

Dynamics of jamming avoidance in echolocating bats

Habitat use and nocturnal activity of lesser short‐tailed bats(Mystacina tuberculata)in comparison with long‐tailed bats(Chalinolobus tuberculatus)in temperate rainforest

Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit

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