The influence of bat echolocation call duration and timing on auditory encoding of predator distance in noctuoid moths

Insect migrations represent large movements of resources across a landscape, which are attractive to predators capable of detecting and catching them. Brazilian free-tailed bats (Tadarida brasiliensis (I. Geoffroy, 1824)) consume migratory noctuid moths, which concentrate in favourable winds resulting in aggregations of prey that attract bats hundreds of metres above ground. Although T. brasiliensis are known to feed on these aggregations of migratory moths, changes in their foraging behaviours have not been linked to moth migration events. We investigated possible shifts in the bats’ foraging behaviours when moths are migrating with respect to altitude and moth abundance. We recorded 1104 echolocation call passes of T. brasiliensis at ground level and at altitudes of ∼100 and ∼200 m above ground level. We found proportionally more bat activity at higher altitudes when migratory moth abundance was high. We also found that bats decreased call frequency and bandwidth and increased call duration at higher altitudes and behaved similarly with increasing moth abundance even at ground level. Our results support predictions that bats change foraging behaviour in response to seasonal availability of migratory moths and document alterations in echolocation call parameters that are consistent with optimizing prey detection.

Download Full-text

Description of Echolocation Call Parameters for Urban Bats in Vietnam as a Step Towards a More Integrated Acoustic Monitoring of Urban Wildlife in Southeast Asia

Diversity ◽

10.3390/d13010018 ◽

2021 ◽

Vol 13 (1) ◽

pp. 18

Author(s):

Long Kim Pham ◽

Bang Van Tran ◽

Quy Tan Le ◽

Trung Thanh Nguyen ◽

Christian C. Voigt

Keyword(s):

Discriminant Function ◽

Discriminant Function Analysis ◽

Function Analysis ◽

Quantitative Description ◽

Southeast Asian ◽

Asian Countries ◽

Echolocation Call ◽

Echolocation Calls ◽

Pilot Work ◽

Southeast Asian Countries

This study is the first step towards more systematic monitoring of urban bat fauna in Vietnam and other Southeast Asian countries by collecting bat echolocation call parameters in Ho Chi Minh and Tra Vinh cities. We captured urban bats and then recorded echolocation calls after releasing in a tent. Additional bat’s echolocation calls from the free-flying bats were recorded at the site where we captured bat. We used the obtained echolocation call parameters for a discriminant function analysis to test the accuracy of classifying these species based on their echolocation call parameters. Data from this pilot work revealed a low level of diversity for the studied bat assemblages. Additionally, the discriminant function analysis successfully classified bats to four bat species with an accuracy of >87.4%. On average, species assignments were correct for all calls from Taphozous melanopogon (100% success rate), for 70% of calls from Pipistrellus javanicus, for 80.8% of calls from Myotis hasseltii and 67.3% of calls from Scotophilus kuhlii. Our study comprises the first quantitative description of echolocation call parameters for urban bats of Vietnam. The success in classifying urban bats based on their echolocation call parameters provides a promising baseline for monitoring the effect of urbanization on bat assemblages in Vietnam and potentially also other Southeast Asian countries.

Download Full-text

Divergent echolocation call frequencies in insular rhinolophids (Chiroptera): a case of character displacement?

Journal of Biogeography ◽

10.1111/j.1365-2699.2007.01762.x ◽

2007 ◽

Vol 34 (12) ◽

pp. 2129-2138 ◽

Cited By ~ 62

Author(s):

Danilo Russo ◽

Mauro Mucedda ◽

Monica Bello ◽

Stefania Biscardi ◽

Ermanno Pidinchedda ◽

...

Keyword(s):

Character Displacement ◽

Echolocation Call

Download Full-text

Echolocation call frequencies of bats vary with body temperature and weather conditions

Animal Behaviour ◽

10.1016/j.anbehav.2021.08.005 ◽

2021 ◽

Vol 180 ◽

pp. 51-61

Author(s):

Huan Wu ◽

Lixin Gong ◽

Tinglei Jiang ◽

Jiang Feng ◽

Aiqing Lin

Keyword(s):

Body Temperature ◽

Weather Conditions ◽

Echolocation Call

Download Full-text

The complex vocalization of Scinax cardosoi (Anura: Hylidae), with comments on advertisement calls in the S. ruber Clade

Phyllomedusa Journal of Herpetology ◽

10.11606/issn.2316-9079.v14i2p127-137 ◽

2015 ◽

Vol 14 (2) ◽

pp. 127 ◽

Cited By ~ 4

Author(s):

Thiago Ribeiro de Carvalho ◽

Lucas Borges Martins ◽

Ariovaldo Antonio Giaretta

Keyword(s):

Original Description ◽

Minas Gerais ◽

The Other ◽

Single Type ◽

Southeastern Brazil ◽

Advertisement Calls ◽

Call Duration ◽

Phenotypic Characters ◽

Acoustic Data ◽

Lower Amplitude

The complex vocalization of Scinax cardosoi (Anura: Hylidae), with comments on advertisement calls in the S. ruber Clade. The complex vocalization of Scinax cardosoi from a population of Minas Gerais in southeastern Brazil is described and compared with available acoustic data for the other species of the S. ruber Clade. Three distinct types of high-pitched, pulsed calls were identified, and are referred to as “short,” “long,” and “trilled” calls. Short calls (16–66 ms) resemble squeaks, and consist of a pulsed signal (8–28 pulses/call) with regular amplitude modulations throughout their duration; the amplitude peak occurs at about the midpoint of the call duration. Long calls (268–518 ms) resemble giggles, and have lower amplitude than short calls; typically, they consist of pulsed note series (1–6 notes/call). Trilled calls resemble insect chirps and have the lowest amplitude of the three call types; they consist of long (1.1–3.0 s) pulsed note series (9–25 notes/call). Acoustic data are taxonomically informative in the Scinax ruber Clade and provide phenotypic characters diagnosing S. cardosoi in addition to those features proposed in its original description. The vocalization repertoire of S. cardosoi resembles the complex vocal repertoires (i.e., multiple call types emitted in variable combinations) of members of the S. catharinae Clade more than some species of the S. ruber Clade, which tend to have simpler call structures (i.e., a single type of multipulsed note).

Download Full-text

Calling depth and time and frequency attributes of harp (Pagophilus groenlandicus) and Weddell (Leptonychotes weddellii) seal underwater vocalizations

Canadian Journal of Zoology ◽

10.1139/z05-135 ◽

2005 ◽

Vol 83 (11) ◽

pp. 1438-1452 ◽

Cited By ~ 5

Author(s):

Hilary B Moors ◽

John M Terhune

Keyword(s):

Light Condition ◽

Weddell Seal ◽

Harp Seal ◽

Vertical Array ◽

Vocal Cords ◽

Leptonychotes Weddellii ◽

Call Duration ◽

Weddell Seals ◽

Pagophilus Groenlandicus ◽

Breeding Seasons

Harp seal (Pagophilus groenlandicus (Erxleben, 1777)) daytime calling depth during the breeding season and Weddell seal (Leptonychotes weddellii (Lesson, 1826)) daytime and nighttime calling depth during the winter and breeding seasons were investigated using a small vertical array with hydrophones placed at depths of 10 and 60 m. Rough calling depth estimates (<35 m, ~35 m, >35 m) and more accurate point depth estimates (±5–10 m in most cases) were obtained. Significantly more calls were produced at depths ≤35 m for both species. The point depth estimates indicated that the calls occurred most frequently at depths >10 m; 60% of harp seal calls and 71% of Weddell seal calls occurred at depths between 10 and 35 m. The seals called predominately within areas of the water column where light would likely penetrate, but still avoided sea-ice interference to some extent. The vocalizations did not change over depth with respect to call type, the number of elements within a call, or total call duration, or with respect to season and light condition for Weddell seals. Frequency (kHz) of calls also did not change with depth, suggesting that harp and Weddell seals control the pitch of their vocalizations with the vocal cords of the larynx.

Download Full-text

Pup ultrasonic isolation calls of six gerbil species and the relationship between acoustic traits and body size

Royal Society Open Science ◽

10.1098/rsos.201558 ◽

2021 ◽

Vol 8 (3) ◽

pp. 201558

Author(s):

Julia D. Kozhevnikova ◽

Ilya A. Volodin ◽

Alexandra S. Zaytseva ◽

Olga G. Ilchenko ◽

Elena V. Volodina

Keyword(s):

Body Size ◽

Discriminant Analysis ◽

Peak Frequency ◽

Meriones Unguiculatus ◽

Similar Relationship ◽

Species Identity ◽

Call Duration ◽

Acoustic Adaptation ◽

Ultrasonic Calls ◽

The Relationship

Among Gerbillinae rodents, ultrasonic calls of adults of small-sized species are typically higher frequency than those of adults of large-sized species. This study investigates whether a similar relationship can be found in pups of six gerbil species ( Dipodillus campestris , Gerbillus perpallidus , Meriones unguiculatus , Meriones vinogradovi , Sekeetamys calurus and Pachyuromys duprasi ). We compared the average values of acoustic variables (duration, fundamental and peak frequency) of ultrasonic calls (20 calls per pup, 1200 in total) recorded from 6- to 10-day-old pups (10 pups per species, 60 in total) isolated for 2 min at 22°C and then weighed and measured for body variables. The longest calls (56 ± 33 ms) were found in the largest species, and the highest frequency calls (74.8 ± 5.59 kHz) were found in the smallest species. However, across species, call duration (ranging from 56 to 159 ms among species) did not display a significant relationship with pup body size; and, among frequency variables, only the minimum fundamental frequency depended on pup body size. Discriminant analysis assigned 100% of calls to the correct species. The effect of species identity on the acoustics was stronger than the effect of body size. We discuss these results with the hypotheses of acoustic adaptation, social complexity, hearing ranges and phylogeny.

Download Full-text

Erratum: Type of shelter and first description of the echolocation call of disk-winged bat (Thyroptera devivoi)

Biota Neotropica ◽

10.1590/1676-0611-bn-2019-0821er ◽

2021 ◽

Keyword(s):

Echolocation Call

Download Full-text

THE EFFECT OF CHANGING CALL DURATION AND CALLING BOUTS ON VIGILANCE IN BRANTS' WHISTLING RAT, PAROTOMYS BRANTSII

Behaviour ◽

10.1163/15685390152822229 ◽

2001 ◽

Vol 138 (10) ◽

pp. 1287-1302 ◽

Cited By ~ 6

Author(s):

Aliza Le Roux ◽

Michael Cherry ◽

Tim Jackson

Keyword(s):

High Risk ◽

Low Risk ◽

Alarm Calls ◽

Playback Experiments ◽

Call Duration ◽

Alarm Calling ◽

Functionally Referential ◽

Long Calls

AbstractThe function of variation in single call duration and alarm calling bouts was investigated in Brants' whistling rat, Parotomys brantsii, by means of playback experiments and video analyses of the vigilance displayed. Short calls are produced in high-risk situations, and long calls in low-risk encounters, but these calls apparently do not communicate this variance in risk to conspecifics. Both short and long single calls induced heightened vigilance in receivers, but rats did not respond differentially to the two call types, and it was concluded that P.brantsii alarm calls are not functionally referential. Multiple calls maintained a state of increased alertness in receivers for a longer period than single calls, even after the bouts had ended, but long bouts (duration: 64 s) did not lead to longer periods of vigilance than short bouts (29 s). Thus the tonic communication hypothesis is only partially supported by our study.

Download Full-text

Rapid jamming avoidance in biosonar

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2006.0047 ◽

2006 ◽

Vol 274 (1610) ◽

pp. 651-660 ◽

Cited By ~ 66

Author(s):

Erin H Gillam ◽

Nachum Ulanovsky ◽

Gary F McCracken

Keyword(s):

Abrupt Change ◽

Considerable Effort ◽

Echolocation Call ◽

Tadarida Brasiliensis ◽

Radar Systems ◽

Spectral Shifts ◽

Processing Strategies ◽

Jamming Avoidance ◽

Sonar Systems ◽

Behavioural Correlations

The sonar systems of bats and dolphins are in many ways superior to man-made sonar and radar systems, and considerable effort has been devoted to understanding the signal-processing strategies underlying these capabilities. A major feature determining the efficiency of sonar systems is the sensitivity to noise and jamming signals. Previous studies indicated that echolocating bats may adjust their signal structure to avoid jamming (‘jamming avoidance response’; JAR). However, these studies relied on behavioural correlations and not controlled experiments. Here, we provide the first experimental evidence for JAR in bats. We presented bats ( Tadarida brasiliensis ) with ‘playback stimuli’ consisting of recorded echolocation calls at one of six frequencies. The bats exhibited a JAR by shifting their call frequency away from the presented playback frequency. When the approaching bats were challenged by an abrupt change in the playback stimulus, they responded by shifting their call frequencies upwards, away from the playback. Interestingly, even bats initially calling below the playback's frequency shifted their frequencies upwards, ‘jumping’ over the playback frequency. These spectral shifts in the bats' calls occurred often within less than 200 ms, in the first echolocation call emitted after the stimulus switch—suggesting that rapid jamming avoidance is important for the bat.

Download Full-text