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Kiai A, Clemens J, Kössl M, Poeppel D, Hechavarría J. Flexible control of vocal timing in Carollia perspicillata bats enables escape from acoustic interference. Commun Biol 2023; 6:1153. [PMID: 37957351 PMCID: PMC10643407 DOI: 10.1038/s42003-023-05507-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
In natural environments, background noise can degrade the integrity of acoustic signals, posing a problem for animals that rely on their vocalizations for communication and navigation. A simple behavioral strategy to combat acoustic interference would be to restrict call emissions to periods of low-amplitude or no noise. Using audio playback and computational tools for the automated detection of over 2.5 million vocalizations from groups of freely vocalizing bats, we show that bats (Carollia perspicillata) can dynamically adapt the timing of their calls to avoid acoustic jamming in both predictably and unpredictably patterned noise. This study demonstrates that bats spontaneously seek out temporal windows of opportunity for vocalizing in acoustically crowded environments, providing a mechanism for efficient echolocation and communication in cluttered acoustic landscapes.
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Affiliation(s)
- Ava Kiai
- Institute for Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany.
| | - Jan Clemens
- European Neuroscience Center, Göttingen, Germany
| | - Manfred Kössl
- Institute for Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - David Poeppel
- Ernst Strüngmann Institute, Frankfurt am Main, Germany
| | - Julio Hechavarría
- Institute for Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany.
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2
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Costalunga G, Carpena CS, Seltmann S, Benichov JI, Vallentin D. Wild nightingales flexibly match whistle pitch in real time. Curr Biol 2023; 33:3169-3178.e3. [PMID: 37453423 PMCID: PMC10414052 DOI: 10.1016/j.cub.2023.06.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/10/2023] [Accepted: 06/15/2023] [Indexed: 07/18/2023]
Abstract
Interactive vocal communication, similar to a human conversation, requires flexible and real-time changes to vocal output in relation to preceding auditory stimuli. These vocal adjustments are essential to ensuring both the suitable timing and content of the interaction. Precise timing of dyadic vocal exchanges has been investigated in a variety of species, including humans. In contrast, the ability of non-human animals to accurately adjust specific spectral features of vocalization extemporaneously in response to incoming auditory information is less well studied. One spectral feature of acoustic signals is the fundamental frequency, which we perceive as pitch. Many animal species can discriminate between sound frequencies, but real-time detection and reproduction of an arbitrary pitch have only been observed in humans. Here, we show that nightingales in the wild can match the pitch of whistle songs while singing in response to conspecifics or pitch-controlled whistle playbacks. Nightingales matched whistles across their entire pitch production range indicating that they can flexibly tune their vocal output along a wide continuum. Prompt whistle pitch matches were more precise than delayed ones, suggesting the direct mapping of auditory information onto a motor command to achieve online vocal replication of a heard pitch. Although nightingales' songs follow annual cycles of crystallization and deterioration depending on breeding status, the observed pitch-matching behavior is present year-round, suggesting a stable neural circuit independent of seasonal changes in physiology. Our findings represent the first case of non-human instantaneous vocal imitation of pitch, highlighting a promising model for understanding sensorimotor transformation within an interactive context. VIDEO ABSTRACT.
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Affiliation(s)
- Giacomo Costalunga
- Neural Circuits for Vocal Communication Research Group, Max Planck Institute for Biological Intelligence, Eberhard-Gwinner-Str., Seewiesen 82319, Germany
| | - Carolina Sánchez Carpena
- Neural Circuits for Vocal Communication Research Group, Max Planck Institute for Biological Intelligence, Eberhard-Gwinner-Str., Seewiesen 82319, Germany
| | - Susanne Seltmann
- Neural Circuits for Vocal Communication Research Group, Max Planck Institute for Biological Intelligence, Eberhard-Gwinner-Str., Seewiesen 82319, Germany
| | - Jonathan I Benichov
- Neural Circuits for Vocal Communication Research Group, Max Planck Institute for Biological Intelligence, Eberhard-Gwinner-Str., Seewiesen 82319, Germany
| | - Daniela Vallentin
- Neural Circuits for Vocal Communication Research Group, Max Planck Institute for Biological Intelligence, Eberhard-Gwinner-Str., Seewiesen 82319, Germany.
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3
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Yantén AV, Cruz-Roa A, Sánchez FA. Traffic noise affects foraging behavior and echolocation in the Lesser Bulldog Bat, Noctilio albiventris (Chiroptera: Noctilionidae). Behav Processes 2022; 203:104775. [DOI: 10.1016/j.beproc.2022.104775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 10/22/2022] [Accepted: 10/26/2022] [Indexed: 11/02/2022]
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Hiraga T, Yamada Y, Kobayashi R. Theoretical investigation of active listening behavior based on the echolocation of CF-FM bats. PLoS Comput Biol 2022; 18:e1009784. [PMID: 36206507 PMCID: PMC9581360 DOI: 10.1371/journal.pcbi.1009784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 10/19/2022] [Accepted: 09/26/2022] [Indexed: 11/18/2022] Open
Abstract
Bats perceive the three-dimensional environment by emitting ultrasound pulses from their nose or mouth and receiving echoes through both ears. To determine the position of a target object, it is necessary to know the distance and direction of the target. Certain bat species that use a combined signal of long constant frequency and short frequency modulated ultrasounds synchronize their pinnae movement with pulse emission, and this behavior has been regarded as helpful for localizing the elevation angle of a reflective sound source. However, the significance of bats' ear motions remains unclear. In this study, we construct a model of an active listening system including the motion of the ears, and conduct mathematical investigations to clarify the importance of ear motion in direction detection of the reflective sound source. In the simulations, direction detection under rigid ear movements with interaural level differences was mathematically investigated by assuming that bats accomplish direction detection using the amplitude modulation in the echoes caused by ear movements. In particular, the ear motion conditions required for direction detection are theoretically investigated through exhaustive simulations of the pseudo-motion of the ears, rather than simulations of the actual ear motions of bats. The theory suggests that only certain ear motions, namely three-axis rotation, allow for accurate and robust direction detection. Our theoretical analysis also strongly supports the behavior whereby bats move their pinnae in the antiphase mode. In addition, we suggest that simple shaped hearing directionality and well-selected uncomplicated ear motions are sufficient to achieve precise and robust direction detection. Our findings and mathematical approach have the potential to be used in the design of active sensing systems in various engineering fields.
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Affiliation(s)
- Takahiro Hiraga
- Department of Mathematical and Life Sciences, Hiroshima University, Department of Sciences, Higashi-Hiroshima, Japan
| | - Yasufumi Yamada
- Program of Mathematical and Life Sciences, Hiroshima University, Department of Sciences, Higashi-Hiroshima, Japan
- * E-mail:
| | - Ryo Kobayashi
- Program of Mathematical and Life Sciences, Hiroshima University, Department of Sciences, Higashi-Hiroshima, Japan
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5
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Fernández Y, Dowdy NJ, Conner WE. High duty cycle moth sounds jam bat echolocation: bats counter with compensatory changes in buzz duration. J Exp Biol 2022; 225:jeb244187. [PMID: 36111562 PMCID: PMC9637272 DOI: 10.1242/jeb.244187] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 08/23/2022] [Indexed: 10/05/2023]
Abstract
Tiger moth species vary greatly in the number of clicks they produce and the resultant duty cycle. Signals with higher duty cycles are expected to more effectively interfere with bat sonar. However, little is known about the minimum duty cycle of tiger moth signals for sonar jamming. Is there a threshold that allows us to classify moths as acoustically aposematic versus sonar jammers based on their duty cycles? We performed playback experiments with three wild-caught adult male bats, Eptesicus fuscus. Bat attacks on tethered moths were challenged using acoustic signals of Bertholdia trigona with modified duty cycles ranging from 0 to 46%. We did not find evidence for a duty cycle threshold; rather, the ability to jam the bat's sonar was a continuous function of duty cycle consistent with a steady increase in the number of clicks arriving during a critical signal processing time window just prior to the arrival of an echo. The proportion of successful captures significantly decreased as the moth duty cycle increased. Our findings suggest that moths cannot be unambiguously classified as acoustically aposematic or sonar jammers based solely on duty cycle. Bats appear to compensate for sonar jamming by lengthening the duration of their terminal buzz and they are more successful in capturing moths when they do so. In contrast to previous findings for bats performing difficult spatial tasks, the number of sonar sound groups decreased in response to high duty cycles and did not affect capture success.
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Affiliation(s)
- Yohami Fernández
- Department of Biology, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, NC 27109, USA
| | - Nicolas J. Dowdy
- Department of Biology, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, NC 27109, USA
- Department of Zoology, Milwaukee Public Museum, 800 West Wells Street, Milwaukee, WI 53233, USA
| | - William E. Conner
- Department of Biology, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, NC 27109, USA
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Beetz MJ, Hechavarría JC. Neural Processing of Naturalistic Echolocation Signals in Bats. Front Neural Circuits 2022; 16:899370. [PMID: 35664459 PMCID: PMC9157489 DOI: 10.3389/fncir.2022.899370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
Abstract
Echolocation behavior, a navigation strategy based on acoustic signals, allows scientists to explore neural processing of behaviorally relevant stimuli. For the purpose of orientation, bats broadcast echolocation calls and extract spatial information from the echoes. Because bats control call emission and thus the availability of spatial information, the behavioral relevance of these signals is undiscussable. While most neurophysiological studies, conducted in the past, used synthesized acoustic stimuli that mimic portions of the echolocation signals, recent progress has been made to understand how naturalistic echolocation signals are encoded in the bat brain. Here, we review how does stimulus history affect neural processing, how spatial information from multiple objects and how echolocation signals embedded in a naturalistic, noisy environment are processed in the bat brain. We end our review by discussing the huge potential that state-of-the-art recording techniques provide to gain a more complete picture on the neuroethology of echolocation behavior.
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Affiliation(s)
- M. Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
| | - Julio C. Hechavarría
- Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
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Pedersen MB, Uebel AS, Beedholm K, Foskolos I, Stidsholt L, Madsen PT. Echolocating Daubenton's bats call louder, but show no spectral jamming avoidance in response to bands of masking noise during a landing task. J Exp Biol 2022; 225:274668. [PMID: 35262171 DOI: 10.1242/jeb.243917] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/02/2022] [Indexed: 11/20/2022]
Abstract
Echolocating bats listen for weak echoes to navigate and hunt, which makes them prone to masking from background noise and jamming from other bats and prey. Like for electrical fish that display clear spectral jamming avoidance responses (JAR), some studies have reported that bats mitigate the effects of jamming by shifting the spectral contents of their calls, thereby reducing acoustic interference to improve echo-to-noise ratios (ENR). Here we test the hypothesis that FM bats employ a spectral JAR in response to six masking noise-bands ranging from 15-90kHz, by measuring the -3dB endpoints and peak frequency of echolocation calls from five male Daubenton's bats (Myotis daubentonii) during a landing task. The bats were trained to land on a noise generating spherical transducer surrounded by a star-shaped microphone array, allowing for acoustic localization and source parameter quantification of on-axis calls. We show that the bats did not employ spectral JAR as the peak frequency during jamming remained unaltered compared to silent controls (all P>0.05, 60.73±0.96 kHz) (mean±s.e.m.), and -3dB endpoints decreased in noise irrespective of treatment-type. Instead, Daubenton's bats responded to acoustic jamming by increasing call amplitude via a Lombard response that was bandwidth dependent ranging from 0.05 [0.04-0.06 mean±95% CI] dB/dB noise for the most narrowband (15-30 kHz) to 0.17 [0.16-0.18] dB/dB noise for the most broadband noise (30-90 kHz). We conclude that Daubenton's bats, despite the vocal flexibility to do so, do not employ a spectral JAR, but defend ENRs via a bandwidth dependent Lombard response.
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Affiliation(s)
- Michael Bjerre Pedersen
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Astrid Særmark Uebel
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Kristian Beedholm
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Ilias Foskolos
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Laura Stidsholt
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Peter Teglberg Madsen
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
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Hase K, Kadoya Y, Takeuchi Y, Kobayasi KI, Hiryu S. Echo reception in group flight by Japanese horseshoe bats, Rhinolophus ferrumequinum nippon. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211597. [PMID: 35154795 PMCID: PMC8825988 DOI: 10.1098/rsos.211597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/14/2022] [Indexed: 05/03/2023]
Abstract
The ability to detect behaviourally relevant sensory information is crucial for survival. Especially when active-sensing animals behave in proximity, mutual interferences may occur. The aim of this study was to examine how active-sensing animals deal with mutual interferences. Echolocation pulses and returning echoes were compared in spaces of various sizes (wide and narrow) in Rhinolophus ferrumequinum nippon flying alone or in a group of three bats. We found that in the narrow space, the group-flying bats increased the duration and bandwidth of the terminal frequency-modulated component of their vocalizations. By contrast, the frequency of the returning echoes did not differ in the presence of conspecifics. We found that their own echo frequencies were compensated within the narrow frequency ranges by Doppler shift compensation. By contrast, the estimated frequencies of the received pulses emitted by the other bats were much more broadly distributed than their echoes. Our results suggest that the bat auditory systems are sharply tuned to a narrow frequency to filter spectral interference from other bats.
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Affiliation(s)
- Kazuma Hase
- Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto 610-0321, Japan
- Research Fellow of Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Yukimi Kadoya
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto 610-0321, Japan
| | - Yuki Takeuchi
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto 610-0321, Japan
| | - Kohta I. Kobayasi
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto 610-0321, Japan
| | - Shizuko Hiryu
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto 610-0321, Japan
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9
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Vernes SC, Kriengwatana BP, Beeck VC, Fischer J, Tyack PL, ten Cate C, Janik VM. The multi-dimensional nature of vocal learning. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200236. [PMID: 34482723 PMCID: PMC8419582 DOI: 10.1098/rstb.2020.0236] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2021] [Indexed: 01/02/2023] Open
Abstract
How learning affects vocalizations is a key question in the study of animal communication and human language. Parallel efforts in birds and humans have taught us much about how vocal learning works on a behavioural and neurobiological level. Subsequent efforts have revealed a variety of cases among mammals in which experience also has a major influence on vocal repertoires. Janik and Slater (Anim. Behav.60, 1-11. (doi:10.1006/anbe.2000.1410)) introduced the distinction between vocal usage and production learning, providing a general framework to categorize how different types of learning influence vocalizations. This idea was built on by Petkov and Jarvis (Front. Evol. Neurosci.4, 12. (doi:10.3389/fnevo.2012.00012)) to emphasize a more continuous distribution between limited and more complex vocal production learners. Yet, with more studies providing empirical data, the limits of the initial frameworks become apparent. We build on these frameworks to refine the categorization of vocal learning in light of advances made since their publication and widespread agreement that vocal learning is not a binary trait. We propose a novel classification system, based on the definitions by Janik and Slater, that deconstructs vocal learning into key dimensions to aid in understanding the mechanisms involved in this complex behaviour. We consider how vocalizations can change without learning, and a usage learning framework that considers context specificity and timing. We identify dimensions of vocal production learning, including the copying of auditory models (convergence/divergence on model sounds, accuracy of copying), the degree of change (type and breadth of learning) and timing (when learning takes place, the length of time it takes and how long it is retained). We consider grey areas of classification and current mechanistic understanding of these behaviours. Our framework identifies research needs and will help to inform neurobiological and evolutionary studies endeavouring to uncover the multi-dimensional nature of vocal learning. This article is part of the theme issue 'Vocal learning in animals and humans'.
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Affiliation(s)
- Sonja C. Vernes
- School of Biology, University of St Andrews, St Andrews, UK
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | | | - Veronika C. Beeck
- Department of Behavioural and Cognitive Biology, University of Vienna, Vienna, Austria
| | - Julia Fischer
- Cognitive Ethology Laboratory, German Primate Centre, Göttingen, Germany
- Department of Primate Cognition, Georg-August-University Göttingen, Göttingen, Germany
| | - Peter L. Tyack
- School of Biology, University of St Andrews, St Andrews, UK
| | - Carel ten Cate
- Institute of Biology, Leiden University, Leiden, The Netherlands
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Gilmour LRV, Holderied MW, Pickering SPC, Jones G. Acoustic deterrents influence foraging activity, flight and echolocation behaviour of free-flying bats. J Exp Biol 2021; 224:272644. [PMID: 34605893 PMCID: PMC8601711 DOI: 10.1242/jeb.242715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 09/28/2021] [Indexed: 11/20/2022]
Abstract
Acoustic deterrents have shown potential as a viable mitigation measure to reduce human impacts on bats; however, the mechanisms underpinning acoustic deterrence of bats have yet to be explored. Bats avoid ambient ultrasound in their environment and alter their echolocation calls in response to masking noise. Using stereo thermal videogrammetry and acoustic methods, we tested predictions that: (i) bats would avoid acoustic deterrents and forage and social call less in a ‘treated airspace’; (ii) deterrents would cause bats to fly with more direct flight paths akin to commuting behaviour and in line with a reduction in foraging activity, resulting in increased flight speed and decreased flight tortuosity; and (iii) bats would alter their echolocation call structure in response to the masking deterrent sound. As predicted, overall bat activity was reduced by 30% and we recorded a significant reduction in counts of Pipistrellus pygmaeus (27%), Myotis spp. (probably M. daubentonii) (26%), and Nyctalus spp. and Eptesicus spp. (68%) passes. Pipistrellus pygmaeus feeding buzzes were also reduced by the deterrent in relation to general activity (by 38%); however, social calls were not (only 23% reduction). Bats also increased their flight speed and reduced the tortuosity of their flight paths, and P. pygmaeus reduced echolocation call bandwidth and start frequency of calls in response to deterrent playback, probably owing to the masking effect of the sound. Deterrence could therefore be used to remove bats from areas where they forage, for example wind turbines and roads, where they may be under threat from direct mortality. Highlighted Article: Using novel flight path tracking and acoustic methods, we show that bats alter their activity, foraging and echolocation behaviour in response to an acoustic deterrent.
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Affiliation(s)
- Lia R V Gilmour
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK.,Department of Applied Sciences, Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Marc W Holderied
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | | | - Gareth Jones
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
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Hase K, Sugihara S, Oka S, Hiryu S. Absence of Jamming Avoidance and Flight Path Similarity in Paired Bent-Winged Bats, Miniopterus Fuliginosus. JOURNAL OF ROBOTICS AND MECHATRONICS 2021. [DOI: 10.20965/jrm.2021.p0564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Echolocating bats perceive their surroundings by listening to the echoes of self-generated ultrasound pulses. When multiple conspecifics fly in close proximity to each other, sounds emitted from nearby individuals could mutually interfere with echo reception. Many studies suggest that bats employ frequency shifts to avoid spectral overlap of pulses with other bats. Technical constraints in recording technology have made it challenging to capture subtle changes in the pulse characteristics of bat calls. Therefore, how bats change their behavior to extract their own echoes in the context of acoustic interference remains unclear. Also, to our best knowledge, no studies have investigated whether individual flight paths change when other bats are present, although movements likely reduce acoustic masking. Here, we recorded the echolocation pulses of bats flying alone or in pairs using telemetry microphones. Flight trajectories were also reconstructed using stereo camera recordings. We found no clear tendency to broaden individual differences in the acoustic characteristics of pulses emitted by pairs of bats compared to bats flying alone. However, some bats showed changes in pulse characteristics when in pairs, which suggests that bats can recognize their own calls based on the initial differences in call characteristics between individuals. In addition, we found that the paired bats spend more time flying in the same directions than in the opposite directions. Besides, we found that the flight paths of bats were more similar in “paired flight trials” than in virtual pairs of paired flight trials. Our results suggest that the bats tend to follow the other bat in paired flight. For the following bat, acoustic interference may be reduced, while the opportunity to eavesdrop on other bats’ calls may be increased.
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12
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Bat echolocation plasticity in allopatry: a call for caution in acoustic identification of Pipistrellus sp. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03002-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
Animals modify their behaviours and interactions in response to changing environments. In bats, environmental adaptations are reflected in echolocation signalling that is used for navigation, foraging and communication. However, the extent and drivers of echolocation plasticity are not fully understood, hindering our identification of bat species with ultrasonic detectors, particularly for cryptic species with similar echolocation calls. We used a combination of DNA barcoding, intensive trapping, roost and emergence surveys and acoustic recording to study a widespread European cryptic species complex (Pipistrellus pipistrellus and Pipistrellus pygmaeus) to investigate whether sibling bat species could exhibit extreme echolocation plasticity in response to certain environmental conditions or behaviours. We found that P. pygmaeus occupied the acoustic niche of their absent congeneric species, producing calls with P. pipistrellus’ characteristic structure and peak frequencies and resulting in false positive acoustic records of that species. Echolocation frequency was significantly affected by the density of bats and by maternity rearing stage, with lower frequency calls emitted when there was a high density of flying bats, and by mothers while juveniles were non-volant. During roost emergence, 29% of calls had peak frequencies typical of P. pipistrellus, with calls as low as 44 kHz, lower than ever documented. We show that automatic and manual call classifiers fail to account for echolocation plasticity, misidentifying P. pygmaeus as P. pipistrellus. Our study raises a vital limitation of using only acoustic sampling in areas with high densities of a single species of a cryptic species pair, with important implications for bat monitoring.
Significance statement
Ultrasonic acoustic detectors are widely used in bat research to establish species inventories and monitor species activity through identification of echolocation calls, enabling new methods to study and understand this elusive understudied group of nocturnal mammals. However, echolocation call signalling in bats is intrinsically different to that of other taxa, serving a main function of navigation and foraging. This study demonstrates an extreme level of plasticity, showing large variation in call frequency and structure in different situations. We showcase the difficulty and limitation in using acoustic sampling alone for bat monitoring and the complications of setting parameters for species identification for manual and automatic call classifiers. Our observations of call frequency variation correlated with density and absence of congenerics provide novel insights of behavioural echolocation plasticity in bats.
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Beetz MJ, Kössl M, Hechavarría JC. The frugivorous bat Carollia perspicillata dynamically changes echolocation parameters in response to acoustic playback. J Exp Biol 2021; 224:jeb.234245. [PMID: 33568443 DOI: 10.1242/jeb.234245] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 01/30/2021] [Indexed: 11/20/2022]
Abstract
Animals 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.
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Affiliation(s)
- M Jerome Beetz
- Institute for Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt am Main, Germany
| | - Manfred Kössl
- Institute for Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt am Main, Germany
| | - Julio C Hechavarría
- Institute for Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt am Main, Germany
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14
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Adverse effects of noise pollution on foraging and drinking behaviour of insectivorous desert bats. Mamm Biol 2021. [DOI: 10.1007/s42991-021-00101-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Castillo-Serrano JG, Norman LJ, Foresteire D, Thaler L. Increased emission intensity can compensate for the presence of noise in human click-based echolocation. Sci Rep 2021; 11:1750. [PMID: 33462283 PMCID: PMC7813859 DOI: 10.1038/s41598-021-81220-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/04/2021] [Indexed: 11/09/2022] Open
Abstract
Echolocating bats adapt their emissions to succeed in noisy environments. In the present study we investigated if echolocating humans can detect a sound-reflecting surface in the presence of noise and if intensity of echolocation emissions (i.e. clicks) changes in a systematic pattern. We tested people who were blind and had experience in echolocation, as well as blind and sighted people who had no experience in echolocation prior to the study. We used an echo-detection paradigm where participants listened to binaural recordings of echolocation sounds (i.e. they did not make their own click emissions), and where intensity of emissions and echoes changed adaptively based on participant performance (intensity of echoes was yoked to intensity of emissions). We found that emission intensity had to systematically increase to compensate for weaker echoes relative to background noise. In fact, emission intensity increased so that spectral power of echoes exceeded spectral power of noise by 12 dB in 4-kHz and 5-kHz frequency bands. The effects were the same across all participant groups, suggesting that this effect occurs independently of long-time experience with echolocation. Our findings demonstrate for the first time that people can echolocate in the presence of noise and suggest that one potential strategy to deal with noise is to increase emission intensity to maintain signal-to-noise ratio of certain spectral components of the echoes.
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Affiliation(s)
- J G Castillo-Serrano
- Department of Psychology, Durham University, Science Site, South Road, Durham, DH1 3LE, UK
| | - L J Norman
- Department of Psychology, Durham University, Science Site, South Road, Durham, DH1 3LE, UK
| | - D Foresteire
- Department of Psychology, Durham University, Science Site, South Road, Durham, DH1 3LE, UK
| | - L Thaler
- Department of Psychology, Durham University, Science Site, South Road, Durham, DH1 3LE, UK.
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16
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Alcázar-Treviño J, Johnson M, Arranz P, Warren VE, Pérez-González CJ, Marques T, Madsen PT, Aguilar de Soto N. Deep-diving beaked whales dive together but forage apart. Proc Biol Sci 2021; 288:20201905. [PMID: 33402065 DOI: 10.1098/rspb.2020.1905] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Echolocating animals that forage in social groups can potentially benefit from eavesdropping on other group members, cooperative foraging or social defence, but may also face problems of acoustic interference and intra-group competition for prey. Here, we investigate these potential trade-offs of sociality for extreme deep-diving Blainville's and Cuvier's beaked whales. These species perform highly synchronous group dives as a presumed predator-avoidance behaviour, but the benefits and costs of this on foraging have not been investigated. We show that group members could hear their companions for a median of at least 91% of the vocal foraging phase of their dives. This enables whales to coordinate their mean travel direction despite differing individual headings as they pursue prey on a minute-by-minute basis. While beaked whales coordinate their echolocation-based foraging periods tightly, individual click and buzz rates are both independent of the number of whales in the group. Thus, their foraging performance is not affected by intra-group competition or interference from group members, and they do not seem to capitalize directly on eavesdropping on the echoes produced by the echolocation clicks of their companions. We conclude that the close diving and vocal synchronization of beaked whale groups that quantitatively reduces predation risk has little impact on foraging performance.
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Affiliation(s)
- Jesús Alcázar-Treviño
- BIOECOMAC, Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna (ULL), Avenida Astrofísico F. Sánchez, s/n. 38206, San Cristóbal de La Laguna (Tenerife), Spain
| | - Mark Johnson
- Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, 8000, Aarhus C, Denmark
| | - Patricia Arranz
- BIOECOMAC, Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna (ULL), Avenida Astrofísico F. Sánchez, s/n. 38206, San Cristóbal de La Laguna (Tenerife), Spain.,Centre for Research into Ecological and Environmental Modelling, University of St Andrews, Fife, KY16 8LB, UK
| | - Victoria E Warren
- Institute of Marine Science, Leigh Marine Laboratory, University of Auckland, 160 Goat Island Road, Leigh 0985, New Zealand
| | - Carlos J Pérez-González
- Departamento de Matemáticas, Estadística e Investigación Operativa, Universidad de La Laguna (ULL), Avenida Astrofísico F. Sánchez, s/n. 38206, San Cristóbal de La Laguna (Tenerife), Spain
| | - Tiago Marques
- Centre for Research into Ecological and Environmental Modelling, University of St Andrews, Fife, KY16 8LB, UK.,Departamento de Biologia Animal, Centro de Estatística e Aplicações, Faculdade de Ciências, Universidade de Lisboa, Bloco C6 - Piso 4, Campo Grande, 1749-016 Lisboa, Portugal
| | - Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, C.F. Moellers Allé 3, 8000, Aarhus C, Denmark
| | - Natacha Aguilar de Soto
- BIOECOMAC, Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna (ULL), Avenida Astrofísico F. Sánchez, s/n. 38206, San Cristóbal de La Laguna (Tenerife), Spain
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17
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Guo D, Ding J, Liu H, Zhou L, Feng J, Luo B, Liu Y. Social calls influence the foraging behavior in wild big-footed myotis. Front Zool 2021; 18:3. [PMID: 33413435 PMCID: PMC7791762 DOI: 10.1186/s12983-020-00384-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 12/21/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Why a variety of social animals emit foraging-associated calls during group foraging remains an open question. These vocalizations may be used to recruit conspecifics to food patches (i.e. food advertisement hypothesis) or defend food resources against competitors (food defence hypothesis), presumably depending on food availability. Insectivorous bats rely heavily on vocalizations for navigation, foraging, and social interactions. In this study, we used free-ranging big-footed myotis (Myotis macrodactylus Temminck, 1840) to test whether social calls produced in a foraging context serve to advertise food patches or to ward off food competitors. Using a combination of acoustic recordings, playback experiments with adult females and dietary monitoring (light trapping and DNA metabarcoding techniques), we investigated the relationship between insect availability and social vocalizations in foraging bats. RESULTS The big-footed myotis uttered low-frequency social calls composed of 7 syllable types during foraging interactions. Although the dietary composition of bats varied across different sampling periods, Diptera, Lepidoptera, and Trichoptera were the most common prey consumed. The number of social vocalizations was primarily predicted by insect abundance, insect species composition, and echolocation vocalizations from conspecifics. The number of conspecific echolocation pulses tended to decrease following the emission of most social calls. Feeding bats consistently decreased foraging attempts and food consumption during playbacks of social calls with distinctive structures compared to control trials. The duration of flight decreased 1.29-1.96 fold in the presence of social calls versus controls. CONCLUSIONS These results support the food defence hypothesis, suggesting that foraging bats employ social calls to engage in intraspecific food competition. This study provides correlative evidence for the role of insect abundance and diversity in influencing the emission of social calls in insectivorous bats. Our findings add to the current knowledge of the function of social calls in echolocating bats.
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Affiliation(s)
- Dongge Guo
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Jianan Ding
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Heng Liu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Lin Zhou
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.,College of Life Science, Jilin Agricultural University, 2888 Xincheng Street, Changchun, 130118, China
| | - Bo Luo
- Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, China West Normal University, Nanchong, 637002, China.
| | - Ying Liu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
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18
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The second harmonic neurons in auditory midbrain of Hipposideros pratti are more tolerant to background white noise. Hear Res 2020; 400:108142. [PMID: 33310564 DOI: 10.1016/j.heares.2020.108142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/29/2020] [Accepted: 12/02/2020] [Indexed: 12/22/2022]
Abstract
Although acoustic communication is inevitably influenced by noise, behaviorally relevant sounds are perceived reliably. The noise-tolerant and -invariant responses of auditory neurons are thought to be the underlying mechanism. So, it is reasonable to speculate that neurons with best frequency tuned to behaviorally relevant sounds will play important role in noise-tolerant perception. Echolocating bats live in groups and emit multiple harmonic signals and analyze the returning echoes to extract information about the target features, making them prone to deal with noise in their natural habitat. The echolocation signal of Hipposideros pratti usually contains 3-4 harmonics (H1H4), the second harmonic has the highest amplitude and is thought to play an essential role during echolocation behavior. Therefore, it is reasonable to propose that neurons tuned to the H2, named the H2 neurons, can be more noise-tolerant to background noise. Taking advantage of bat's stereotypical echolocation signal and single-cell recording, our present study showed that the minimal threshold increases (12.2 dB) of H2 neurons in the auditory midbrain were comparable to increase in bat's call intensity (14.2 dB) observed in 70 dB SPL white noise condition, indicating that the H2 neurons could work as background noise monitor. The H2 neurons had higher minimal thresholds and sharper frequency tuning, which enabled them to be more tolerant to background noise. Furthermore, the H2 neurons had consistent best amplitude spikes and sharper intensity tuning in background white noise condition than in silence. Taken together, these results suggest that the H2 neurons might account for noise-tolerant perception of behaviorally relevant sounds.
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19
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Shaffer I, Abaid N. Transfer Entropy Analysis of Interactions between Bats Using Position and Echolocation Data. ENTROPY (BASEL, SWITZERLAND) 2020; 22:E1176. [PMID: 33286944 PMCID: PMC7597347 DOI: 10.3390/e22101176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 06/12/2023]
Abstract
Many animal species, including many species of bats, exhibit collective behavior where groups of individuals coordinate their motion. Bats are unique among these animals in that they use the active sensing mechanism of echolocation as their primary means of navigation. Due to their use of echolocation in large groups, bats run the risk of signal interference from sonar jamming. However, several species of bats have developed strategies to prevent interference, which may lead to different behavior when flying with conspecifics than when flying alone. This study seeks to explore the role of this acoustic sensing on the behavior of bat pairs flying together. Field data from a maternity colony of gray bats (Myotis grisescens) were collected using an array of cameras and microphones. These data were analyzed using the information theoretic measure of transfer entropy in order to quantify the interaction between pairs of bats and to determine the effect echolocation calls have on this interaction. This study expands on previous work that only computed information theoretic measures on the 3D position of bats without echolocation calls or that looked at the echolocation calls without using information theoretic analyses. Results show that there is evidence of information transfer between bats flying in pairs when time series for the speed of the bats and their turning behavior are used in the analysis. Unidirectional information transfer was found in some subsets of the data which could be evidence of a leader-follower interaction.
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Affiliation(s)
- Irena Shaffer
- Engineering Mechanics Program, Virginia Tech, Blacksburg, VA 24061, USA;
| | - Nicole Abaid
- Department of Mathematics, Virginia Tech, Blacksburg, VA 24061, USA
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20
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Kohles JE, Carter GG, Page RA, Dechmann DKN. Socially foraging bats discriminate between group members based on search-phase echolocation calls. Behav Ecol 2020. [DOI: 10.1093/beheco/araa056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Animals have evolved diverse strategies to use social information for increasing foraging success and efficiency. Echolocating bats, for example, can eavesdrop on bats foraging nearby because they shift from search-phase calls to feeding buzzes when they detect prey. Feeding buzzes can directly convey information about prey presence, but it is unknown whether search-phase calls also convey social information. Here, we investigated whether search-phase echolocation calls, distinct calls produced by some bat species to scan large open areas for prey, can additionally convey individual identity. We tested this in Molossus molossus, a neotropical insectivorous bat that forages with group members, presumably to find ephemeral insect swarms more efficiently. We caught M. molossus from six different social groups and recorded their search-phase calls during a standardized release procedure, then recaptured and tested 19 marked bats with habituation–dishabituation playback experiments. We showed that they can discriminate between group members based on search-phase calls, and our statistical analysis of call parameters supported the presence of individual signatures in search-phase calls. Individual discrimination is a prerequisite of individual recognition, which may allow M. molossus to maintain contact with group members while foraging without using specialized signals for communication.
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Affiliation(s)
- Jenna E Kohles
- Department of Migration, Max Planck Institute of Animal Behavior, Am Obstberg, Radolfzell, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße, Konstanz, Germany
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
- Gamboa Laboratory, Smithsonian Tropical Research Institute, Ave. Luis F. Clement, Balboa, Ancón, Panamá, República de Panamá
| | - Gerald G Carter
- Gamboa Laboratory, Smithsonian Tropical Research Institute, Ave. Luis F. Clement, Balboa, Ancón, Panamá, República de Panamá
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Aronoff Laboratory, Columbus, OH , USA
| | - Rachel A Page
- Gamboa Laboratory, Smithsonian Tropical Research Institute, Ave. Luis F. Clement, Balboa, Ancón, Panamá, República de Panamá
| | - Dina K N Dechmann
- Department of Migration, Max Planck Institute of Animal Behavior, Am Obstberg, Radolfzell, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße, Konstanz, Germany
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
- Gamboa Laboratory, Smithsonian Tropical Research Institute, Ave. Luis F. Clement, Balboa, Ancón, Panamá, República de Panamá
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21
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Mazar O, Yovel Y. A sensorimotor model shows why a spectral jamming avoidance response does not help bats deal with jamming. eLife 2020; 9:55539. [PMID: 32718437 PMCID: PMC7406351 DOI: 10.7554/elife.55539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/21/2020] [Indexed: 12/05/2022] Open
Abstract
For decades, researchers have speculated how echolocating bats deal with masking by conspecific calls when flying in aggregations. To date, only a few attempts have been made to mathematically quantify the probability of jamming, or its effects. We developed a comprehensive sensorimotor predator-prey simulation, modeling numerous bats foraging in proximity. We used this model to examine the effectiveness of a spectral Jamming Avoidance Response (JAR) as a solution for the masking problem. We found that foraging performance deteriorates when bats forage near conspecifics, however, applying a JAR does not improve insect sensing or capture. Because bats constantly adjust their echolocation to the performed task (even when flying alone), further shifting the signals' frequencies does not mitigate jamming. Our simulations explain how bats can hunt successfully in a group despite competition and despite potential masking. This research demonstrates the advantages of a modeling approach when examining a complex biological system.
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Affiliation(s)
- Omer Mazar
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Yossi Yovel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,Department of Zoology, Tel Aviv University, Tel Aviv, Israel
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22
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Zweifel NO, Hartmann MJZ. Defining "active sensing" through an analysis of sensing energetics: homeoactive and alloactive sensing. J Neurophysiol 2020; 124:40-48. [PMID: 32432502 DOI: 10.1152/jn.00608.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The term "active sensing" has been defined in multiple ways. Most strictly, the term refers to sensing that uses self-generated energy to sample the environment (e.g., echolocation). More broadly, the definition includes all sensing that occurs when the sensor is moving (e.g., tactile stimuli obtained by an immobile versus moving fingertip) and, broader still, includes all sensing guided by attention or intent (e.g., purposeful eye movements). The present work offers a framework to help disambiguate aspects of the "active sensing" terminology and reveals properties of tactile sensing unique among all modalities. The framework begins with the well-described "sensorimotor loop," which expresses the perceptual process as a cycle involving four subsystems: environment, sensor, nervous system, and actuator. Using system dynamics, we examine how information flows through the loop. This "sensory-energetic loop" reveals two distinct sensing mechanisms that subdivide active sensing into homeoactive and alloactive sensing. In homeoactive sensing, the animal can change the state of the environment, while in alloactive sensing the animal can alter only the sensor's configurational parameters and thus the mapping between input and output. Given these new definitions, examination of the sensory-energetic loop helps identify two unique characteristics of tactile sensing: 1) in tactile systems, alloactive and homeoactive sensing merge to a mutually controlled sensing mechanism, and 2) tactile sensing may require fundamentally different predictions to anticipate reafferent input. We expect this framework may help resolve ambiguities in the active sensing community and form a basis for future theoretical and experimental work regarding alloactive and homeoactive sensing.
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Affiliation(s)
- Nadina O Zweifel
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - Mitra J Z Hartmann
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois.,Department of Mechanical Engineering, Northwestern University, Evanston, Illinois
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23
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Zamora‐Gutierrez V, Ortega J, Avila‐Flores R, Aguilar‐Rodríguez PA, Alarcón‐Montano M, Avila‐Torresagatón LG, Ayala‐Berdón J, Bolívar‐Cimé B, Briones‐Salas M, Chan‐Noh M, Chávez‐Cauich M, Chávez C, Cortés‐Calva P, Cruzado J, Cuevas JC, Del Real‐Monroy M, Elizalde‐Arellano C, García‐Luis M, García‐Morales R, Guerrero JA, Guevara‐Carrizales AA, Gutiérrez EG, Hernández‐Mijangos LA, Ibarra‐López MP, Iñiguez‐Dávalos LI, León‐Madrazo R, López‐González C, López‐Téllez MC, López‐Vidal JC, Martínez‐Balvanera S, Montiel‐Reyes F, Murrieta‐Galindo R, Orozco‐Lugo CL, Pech‐Canché JM, Pérez‐Pérez L, Ramírez‐Martínez MM, Rizo‐Aguilar A, Robredo‐Esquivelzeta E, Rodas‐Martínez AZ, Rojo‐Cruz MA, Selem‐Salas CI, Uribe‐Bencomo E, Vargas‐Contreras JA, MacSwiney G. MC. The Sonozotz project: Assembling an echolocation call library for bats in a megadiverse country. Ecol Evol 2020; 10:4928-4943. [PMID: 32551071 PMCID: PMC7297765 DOI: 10.1002/ece3.6245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 11/23/2022] Open
Abstract
Bat acoustic libraries are important tools that assemble echolocation calls to allow the comparison and discrimination to confirm species identifications. The Sonozotz project represents the first nation-wide library of bat echolocation calls for a megadiverse country. It was assembled following a standardized recording protocol that aimed to cover different recording habitats, recording techniques, and call variation inherent to individuals. The Sonozotz project included 69 species of echolocating bats, a high species richness that represents 50% of bat species found in the country. We include recommendations on how the database can be used and how the sampling methods can be potentially replicated in countries with similar environmental and geographic conditions. To our knowledge, this represents the most exhaustive effort to date to document and compile the diversity of bat echolocation calls for a megadiverse country. This database will be useful to address a range of ecological questions including the effects of anthropogenic activities on bat communities through the analysis of bat sound.
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Affiliation(s)
- Veronica Zamora‐Gutierrez
- CONACYT—Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Durango (CIIDIR)Instituto Politécnico NacionalDurangoMéxico
| | - Jorge Ortega
- Departamento de ZoologíaEscuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalCiudad de MéxicoMéxico
| | - Rafael Avila‐Flores
- División Académica de Ciencias BiológicasUniversidad Juárez Autónoma de TabascoVillahermosaMéxico
| | - Pedro Adrián Aguilar‐Rodríguez
- Centro de Investigaciones TropicalesUniversidad VeracruzanaXalapaMéxico
- Universidad Autónoma de TlaxcalaTlaxcala de XicohténcatlMéxico
| | | | | | | | | | - Miguel Briones‐Salas
- Centro Interdisciplinario de Investigación para el Desarrollo Integral RegionalUnidad Oaxaca (CIIDIR)Instituto Politécnico NacionalOaxacaMéxico
| | - Martha Chan‐Noh
- Campus de Ciencias Biológicas‐AgropecuariasUniversidad Autónoma de YucatánMéridaMéxico
| | - Manuel Chávez‐Cauich
- Campus de Ciencias Biológicas‐AgropecuariasUniversidad Autónoma de YucatánMéridaMéxico
| | - Cuauhtémoc Chávez
- Departamento de Ciencias AmbientalesUniversidad Autónoma Metropolitana‐Unidad LermaLermaMéxico
| | - Patricia Cortés‐Calva
- Programa de Planeación Ambiental y ConservaciónCentro de Investigaciones Biológicas del Noroeste, S.C.La PazMéxico
| | | | - Jesús Carlo Cuevas
- Ingeniería en Recursos Naturales y AgropecuariosUniversidad de GuadalajaraAutlánMéxico
| | | | - Cynthia Elizalde‐Arellano
- Departamento de ZoologíaEscuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalCiudad de MéxicoMéxico
| | - Margarita García‐Luis
- Centro Interdisciplinario de Investigación para el Desarrollo Integral RegionalUnidad Oaxaca (CIIDIR)Instituto Politécnico NacionalOaxacaMéxico
- Instituto Tecnológico del Valle de OaxacaXoxocotlánMéxico
| | | | - José Antonio Guerrero
- Facultad de Ciencias BiológicasUniversidad Autónoma del Estado de MorelosCuernavacaMéxico
| | | | - Edgar G. Gutiérrez
- Departamento de ZoologíaEscuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalCiudad de MéxicoMéxico
| | | | | | | | - Rafael León‐Madrazo
- División Académica de Ciencias BiológicasUniversidad Juárez Autónoma de TabascoVillahermosaMéxico
| | - Celia López‐González
- Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Durango (CIIDIR)Instituto Politécnico NacionalDurangoMéxico
| | | | - Juan Carlos López‐Vidal
- Departamento de ZoologíaEscuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalCiudad de MéxicoMéxico
| | | | - Fernando Montiel‐Reyes
- Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Durango (CIIDIR)Instituto Politécnico NacionalDurangoMéxico
| | | | - Carmen Lorena Orozco‐Lugo
- Centro de Investigación en Biodiversidad y ConservaciónUniversidad Autónoma del Estado de MorelosCuernavacaMéxico
| | - Juan M. Pech‐Canché
- Facultad de Ciencias Biológicas y AgropecuariasUniversidad VeracruzanaTuxpanMéxico
| | - Lucio Pérez‐Pérez
- División Académica de Ciencias BiológicasUniversidad Juárez Autónoma de TabascoVillahermosaMéxico
| | | | - Areli Rizo‐Aguilar
- Facultad de Ciencias Químicas e IngenieríaUniversidad Autónoma del Estado de MorelosCuernavacaMéxico
| | | | - Alba Z. Rodas‐Martínez
- División Académica de Ciencias BiológicasUniversidad Juárez Autónoma de TabascoVillahermosaMéxico
| | | | | | - Elena Uribe‐Bencomo
- Campus de Ciencias Biológicas‐AgropecuariasUniversidad Autónoma de YucatánMéridaMéxico
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24
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Izadi MR, Stevenson R, Kloepper LN. Separation of overlapping sources in bioacoustic mixtures. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:1688. [PMID: 32237826 DOI: 10.1121/10.0000932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/02/2020] [Indexed: 06/11/2023]
Abstract
Source separation is an important step to study signals that are not easy or possible to record individually. Common methods such as deep clustering, however, cannot be applied to signals of an unknown number of sources and/or signals that overlap in time and/or frequency-a common problem in bioacoustic recordings. This work presents an approach, using a supervised learning framework, to parse individual sources from a spectrogram of a mixture that contains a variable number of overlapping sources. This method isolates individual sources in the time-frequency domain using only one function but in two separate steps, one for the detection of the number of sources and corresponding bounding boxes, and a second step for the segmentation in which masks of individual sounds are extracted. This approach handles the full separation of overlapping sources in both time and frequency using deep neural networks in an applicable manner to other tasks such as bird audio detection. This paper presents method and reports on its performance to parse individual bat signals from recordings containing hundreds of overlapping bat echolocation signals. This method can be extended to other bioacoustic recordings with a variable number of sources and signals that overlap in time and/or frequency.
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Affiliation(s)
- Mohammad Rasool Izadi
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Robert Stevenson
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Laura N Kloepper
- Department of Biology, Saint Mary's College, Notre Dame, Indiana 46556, USA
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25
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Modeling active sensing reveals echo detection even in large groups of bats. Proc Natl Acad Sci U S A 2019; 116:26662-26668. [PMID: 31822613 DOI: 10.1073/pnas.1821722116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Active sensing animals perceive their surroundings by emitting probes of energy and analyzing how the environment modulates these probes. However, the probes of conspecifics can jam active sensing, which should cause problems for groups of active sensing animals. This problem was termed the cocktail party nightmare for echolocating bats: as bats listen for the faint returning echoes of their loud calls, these echoes will be masked by the loud calls of other close-by bats. Despite this problem, many bats echolocate in groups and roost socially. Here, we present a biologically parametrized framework to quantify echo detection in groups. Incorporating properties of echolocation, psychoacoustics, acoustics, and group flight, we quantify how well bats flying in groups can detect each other despite jamming. A focal bat in the center of a group can detect neighbors in group sizes of up to 100 bats. With increasing group size, fewer and only the closest and frontal neighbors are detected. Neighbor detection is improved by longer call intervals, shorter call durations, denser groups, and more variable flight and sonar beam directions. Our results provide a quantification of the sensory input of echolocating bats in collective group flight, such as mating swarms or emergences. Our results further generate predictions on the sensory strategies bats may use to reduce jamming in the cocktail party nightmare. Lastly, we suggest that the spatially limited sensory field of echolocators leads to limited interactions within a group, so that collective behavior is achieved by following only nearest neighbors.
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Vernes SC, Wilkinson GS. Behaviour, biology and evolution of vocal learning in bats. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190061. [PMID: 31735153 DOI: 10.1098/rstb.2019.0061] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The comparative approach can provide insight into the evolution of human speech, language and social communication by studying relevant traits in animal systems. Bats are emerging as a model system with great potential to shed light on these processes given their learned vocalizations, close social interactions, and mammalian brains and physiology. A recent framework outlined the multiple levels of investigation needed to understand vocal learning across a broad range of non-human species, including cetaceans, pinnipeds, elephants, birds and bats. Here, we apply this framework to the current state-of-the-art in bat research. This encompasses our understanding of the abilities bats have displayed for vocal learning, what is known about the timing and social structure needed for such learning, and current knowledge about the prevalence of the trait across the order. It also addresses the biology (vocal tract morphology, neurobiology and genetics) and evolution of this trait. We conclude by highlighting some key questions that should be answered to advance our understanding of the biological encoding and evolution of speech and spoken communication. This article is part of the theme issue 'What can animal communication teach us about human language?'
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Affiliation(s)
- Sonja C Vernes
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, PO Box 310, Nijmegen 6500 AH, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Kapittelweg 29, Nijmegen 6525 EN, The Netherlands
| | - Gerald S Wilkinson
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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27
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Zhao L, Roy S, Wang X. Rapid modulations of the vocal structure in marmoset monkeys. Hear Res 2019; 384:107811. [PMID: 31678893 DOI: 10.1016/j.heares.2019.107811] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/05/2019] [Accepted: 10/07/2019] [Indexed: 10/25/2022]
Abstract
Humans and some animal species show flexibility in vocal production either voluntarily or in response to environmental cues. Studies have shown rapid spectrotemporal changes in speech or vocalizations during altered auditory feedback in humans, songbirds and bats. Non-human primates, however, have long been considered lacking the ability to modify spectrotemporal structures of their vocalizations. Here we tested the ability of the common marmoset (Callithrix jacchus), a highly vocal New World primate species to alter spectral and temporal structures of their species-specific vocalizations in the presence of perturbation signals. By presenting perturbation noises while marmosets were vocalizing phee calls, we showed that they were able to change in real-time the duration or spectral trajectory of an ongoing phee phrase by either terminating it before its completion, making rapid shifts in fundamental frequency or in some cases prolonging the duration beyond the natural range of phee calls. In some animals, we observed fragmented phee calls which were not produced by marmosets in their natural environment. Interestingly, some perturbation-induced changes persisted even in the absence of the perturbation noises. These observations provide further evidence that marmoset monkeys are capable of rapidly modulating their vocal structure and suggested potential voluntary vocal control by this non-human primate species.
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Affiliation(s)
- Lingyun Zhao
- Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Sabyasachi Roy
- Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Xiaoqin Wang
- Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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28
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Wirthlin M, Chang EF, Knörnschild M, Krubitzer LA, Mello CV, Miller CT, Pfenning AR, Vernes SC, Tchernichovski O, Yartsev MM. A Modular Approach to Vocal Learning: Disentangling the Diversity of a Complex Behavioral Trait. Neuron 2019; 104:87-99. [PMID: 31600518 PMCID: PMC10066796 DOI: 10.1016/j.neuron.2019.09.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/18/2019] [Accepted: 09/21/2019] [Indexed: 12/14/2022]
Abstract
Vocal learning is a behavioral trait in which the social and acoustic environment shapes the vocal repertoire of individuals. Over the past century, the study of vocal learning has progressed at the intersection of ecology, physiology, neuroscience, molecular biology, genomics, and evolution. Yet, despite the complexity of this trait, vocal learning is frequently described as a binary trait, with species being classified as either vocal learners or vocal non-learners. As a result, studies have largely focused on a handful of species for which strong evidence for vocal learning exists. Recent studies, however, suggest a continuum in vocal learning capacity across taxa. Here, we further suggest that vocal learning is a multi-component behavioral phenotype comprised of distinct yet interconnected modules. Discretizing the vocal learning phenotype into its constituent modules would facilitate integration of findings across a wider diversity of species, taking advantage of the ways in which each excels in a particular module, or in a specific combination of features. Such comparative studies can improve understanding of the mechanisms and evolutionary origins of vocal learning. We propose an initial set of vocal learning modules supported by behavioral and neurobiological data and highlight the need for diversifying the field in order to disentangle the complexity of the vocal learning phenotype.
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29
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Page RA, Bernal XE. The challenge of detecting prey: Private and social information use in predatory bats. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13439] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Ximena E. Bernal
- Smithsonian Tropical Research Institute Balboa Panamá
- Department of Biological Sciences Purdue University West Lafayette Indiana
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30
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Guo D, Luo B, Zhang K, Liu M, Metzner W, Liu Y, Feng J. Social vocalizations of big-footed myotis (Myotis macrodactylus) during foraging. Integr Zool 2019; 14:446-459. [PMID: 30585415 DOI: 10.1111/1749-4877.12367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Acoustic signals play a crucial role in transmitting information and maintaining social stability in gregarious animals, especially in echolocating bats, which rely primarily on biological sonar for navigating in the dark. In the context of foraging without relying on tactile, visual or olfactory cues, acoustic signals convey information not only on food but also on ownership and defense of resources. However, studies on such information remain fragmentary. In the present study, we aim to document the social vocal repertoire of Myotis macrodactylus at natural foraging sites. Multiple acoustic analyses and spectrographic classification revealed a rich foraging vocal repertoire comprising 6 simple syllables and 2 composites. Discriminant function analyses associated with a subset-validation procedure provided an optimal method to spectrographically classify all recorded sounds into different syllable types. Multidimensional scaling of median values of multiple parameters further confirmed notable differences among these syllables in a 3-D space. In addition, Euclidean distance analysis showed that there were some spectral similarities between specific social vocal syllables and feeding buzzes, which implied a potential jamming role. Altogether, the data indicate that bats at foraging sites under natural conditions used variant social vocalizations with different functions in addition to echolocation calls, providing supporting evidence for further work on the function and vocal mechanisms of acoustic communication in mammals.
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Affiliation(s)
- Dongge Guo
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Bo Luo
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China.,Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, China West Normal University, Nanchong, China
| | - Kangkang Zhang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Muxun Liu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Walter Metzner
- Department of Integrative Biology & Physiology, University of California, Los Angeles, California, USA
| | - Ying Liu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China.,College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
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31
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Genzel D, Desai J, Paras E, Yartsev MM. Long-term and persistent vocal plasticity in adult bats. Nat Commun 2019; 10:3372. [PMID: 31358755 PMCID: PMC6662767 DOI: 10.1038/s41467-019-11350-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 07/05/2019] [Indexed: 12/25/2022] Open
Abstract
Bats exhibit a diverse and complex vocabulary of social communication calls some of which are believed to be learned during development. This ability to produce learned, species-specific vocalizations – a rare trait in the animal kingdom – requires a high-degree of vocal plasticity. Bats live extremely long lives in highly complex and dynamic social environments, which suggests that they might also retain a high degree of vocal plasticity in adulthood, much as humans do. Here, we report persistent vocal plasticity in adult bats (Rousettus aegyptiacus) following exposure to broad-band, acoustic perturbation. Our results show that adult bats can not only modify distinct parameters of their vocalizations, but that these changes persist even after noise cessation – in some cases lasting several weeks or months. Combined, these findings underscore the potential importance of bats as a model organism for studies of vocal plasticity, including in adulthood. Bats are long-lived animals that can produce a complex vocabulary of social communication calls. Here, the authors show that even in adulthood, bats retain the ability to adaptively introduce long-term modifications to their vocalizations, showing persistent vocal plasticity.
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Affiliation(s)
- Daria Genzel
- Helen Wills Neuroscience Institute and Department of Bioengineering, UC Berkeley, Berkeley, CA, 94720, USA
| | - Janki Desai
- Department of Integrative Biology, UC Berkeley, Berkeley, CA, 94720, USA
| | - Elana Paras
- Department of Environmental Science, Policy, and Management, UC Berkeley, Berkeley, CA, 94720, USA
| | - Michael M Yartsev
- Helen Wills Neuroscience Institute and Department of Bioengineering, UC Berkeley, Berkeley, CA, 94720, USA.
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32
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Thaler L, De Vos HPJC, Kish D, Antoniou M, Baker CJ, Hornikx MCJ. Human Click-Based Echolocation of Distance: Superfine Acuity and Dynamic Clicking Behaviour. J Assoc Res Otolaryngol 2019; 20:499-510. [PMID: 31286299 PMCID: PMC6797687 DOI: 10.1007/s10162-019-00728-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/06/2019] [Indexed: 01/25/2023] Open
Abstract
Some people who are blind have trained themselves in echolocation using mouth clicks. Here, we provide the first report of psychophysical and clicking data during echolocation of distance from a group of 8 blind people with experience in mouth click-based echolocation (daily use for > 3 years). We found that experienced echolocators can detect changes in distance of 3 cm at a reference distance of 50 cm, and a change of 7 cm at a reference distance of 150 cm, regardless of object size (i.e. 28.5 cm vs. 80 cm diameter disk). Participants made mouth clicks that were more intense and they made more clicks for weaker reflectors (i.e. same object at farther distance, or smaller object at same distance), but number and intensity of clicks were adjusted independently from one another. The acuity we found is better than previous estimates based on samples of sighted participants without experience in echolocation or individual experienced participants (i.e. single blind echolocators tested) and highlights adaptation of the perceptual system in blind human echolocators. Further, the dynamic adaptive clicking behaviour we observed suggests that number and intensity of emissions serve separate functions to increase SNR. The data may serve as an inspiration for low-cost (i.e. non-array based) artificial ‘cognitive’ sonar and radar systems, i.e. signal design, adaptive pulse repetition rate and intensity. It will also be useful for instruction and guidance for new users of echolocation.
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Affiliation(s)
- Lore Thaler
- Department of Psychology, Durham University, Science Site, South Road, Durham, DH1 3LE, UK.
| | - H P J C De Vos
- Eindhoven University of Technology, Eindhoven, The Netherlands
| | - D Kish
- World Access for the Blind, Placentia, CA, USA
| | - M Antoniou
- Department of Electronic Electrical and Systems Engineering, University of Birmingham, Birmingham, UK
| | - C J Baker
- Department of Electronic Electrical and Systems Engineering, University of Birmingham, Birmingham, UK
| | - M C J Hornikx
- Eindhoven University of Technology, Eindhoven, The Netherlands
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33
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Jones TK, Conner WE. The jamming avoidance response in echolocating bats. Commun Integr Biol 2019; 12:10-13. [PMID: 30891113 PMCID: PMC6419628 DOI: 10.1080/19420889.2019.1568818] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 01/09/2019] [Indexed: 10/29/2022] Open
Abstract
Bats face many sources of acoustic interference in their natural environments, including other bats and potential prey items that affect their ability to interpret the returning echoes of their biosonar signals. To be able to navigate and forage successfully, bats must be able to counteract this interference and one of the ways they achieve this is by altering the various parameters of their echolocation. We describe these changes in signal design within the context of a modified definition of the jamming avoidance response originally applied to the signal changes of weakly electric fish. Both of these groups use active sensory systems that exhibit similarities in function but we take this opportunity to highlight major differences each groups' response to signal interference. These discrepancies form the basis of our need for an expanded description of the jamming avoidance response in echolocating bats.
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Affiliation(s)
- Te K Jones
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - William E Conner
- Department of Biology, Wake Forest University, Winston-Salem, NC, USA
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34
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Kloepper LN, Branstetter BK. The effect of jamming stimuli on the echolocation behavior of the bottlenose dolphin, Tursiops truncatus. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:1341. [PMID: 31067932 DOI: 10.1121/1.5093636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/22/2019] [Indexed: 06/09/2023]
Abstract
Echolocating bats and odontocetes face the potential challenge of acoustic interference from neighbors, or sonar jamming. To counter this, many bat species have adapted jamming avoidance strategies to improve signal detection, but any such avoidance strategies in dolphins is unknown. This study provides an investigation into whether dolphins modify echolocation behavior during jamming scenarios. Recorded echolocation clicks were projected at different click repetition rates and at different aspect angles relative to two dolphins' heads while each dolphin was performing a target detection task. Changes in the timing, amplitude, and frequency of structure of the dolphin's emitted signals were compared to determine if and how dolphins modify echolocation when faced with potentially interfering conspecific echolocation signals. The results indicate that both dolphins demonstrated different responses when faced with jamming scenarios, which may reflect optimal strategies according to individual auditory perception abilities.
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Affiliation(s)
- Laura N Kloepper
- Department of Biology, Saint Mary's College, Notre Dame, Indiana 46556, USA
| | - Brian K Branstetter
- National Marine Mammal Foundation, 2240 Shelter Island Drive, #200, San Diego, California 92106, USA
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35
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Greif S, Yovel Y. Using on-board sound recordings to infer behaviour of free-moving wild animals. ACTA ACUST UNITED AC 2019; 222:222/Suppl_1/jeb184689. [PMID: 30728226 DOI: 10.1242/jeb.184689] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Technological advances in the last 20 years have enabled researchers to develop increasingly sophisticated miniature devices (tags) that record an animal's behaviour not from an observational, external viewpoint, but directly on the animals themselves. So far, behavioural research with these tags has mostly been conducted using movement or acceleration data. But on-board audio recordings have become more and more common following pioneering work in marine mammal research. The first questions that come to mind when recording sound on-board animals concern their vocal behaviour. When are they calling? How do they adjust their behaviour? What acoustic parameters do they change and how? However, other topics like foraging behaviour, social interactions or environmental acoustics can now be addressed as well and offer detailed insight into the animals' daily life. In this Review, we discuss the possibilities, advantages and limitations of on-board acoustic recordings. We focus primarily on bats as their active-sensing, echolocating lifestyle allows many approaches to a multi-faceted acoustic assessment of their behaviour. The general ideas and concepts, however, are applicable to many animals and hopefully will demonstrate the versatility of on-board acoustic recordings and stimulate new research.
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Affiliation(s)
- Stefan Greif
- Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yossi Yovel
- Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
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36
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Voigt CC, Frick WF, Holderied MW, Holland R, Kerth G, Mello MAR, Plowright RK, Swartz S, Yovel Y. PRINCIPLES AND PATTERNS OF BAT MOVEMENTS: FROM AERODYNAMICS TO ECOLOGY. QUARTERLY REVIEW OF BIOLOGY 2019; 92:267-287. [PMID: 29861509 DOI: 10.1086/693847] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Movement ecology as an integrative discipline has advanced associated fields because it presents not only a conceptual framework for understanding movement principles but also helps formulate predictions about the consequences of movements for animals and their environments. Here, we synthesize recent studies on principles and patterns of bat movements in context of the movement ecology paradigm. The motion capacity of bats is defined by their highly articulated, flexible wings. Power production during flight follows a U-shaped curve in relation to speed in bats yet, in contrast to birds, bats use mostly exogenous nutrients for sustained flight. The navigation capacity of most bats is dominated by the echolocation system, yet other sensory modalities, including an iron-based magnetic sense, may contribute to navigation depending on a bat's familiarity with the terrain. Patterns derived from these capacities relate to antagonistic and mutualistic interactions with food items. The navigation capacity of bats may influence their sociality, in particular, the extent of group foraging based on eavesdropping on conspecifics' echolocation calls. We infer that understanding the movement ecology of bats within the framework of the movement ecology paradigm provides new insights into ecological processes mediated by bats, from ecosystem services to diseases.
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Affiliation(s)
- Christian C Voigt
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research 10315 Berlin, Germany, Institute of Biology, Freie Universität Berlin 14195 Berlin, Germany
| | - Winifred F Frick
- Bat Conservation International Austin, Texas 78716 USA, Ecology and Evolutionary Biology, University of California Santa Cruz, California 95064 USA
| | - Marc W Holderied
- School of Biological Sciences, Bristol University Bristol BS8 1TQ United Kingdom
| | - Richard Holland
- School of Biological Sciences, Bangor University Bangor, Gwynedd LL57 2UW United Kingdom
| | - Gerald Kerth
- Applied Zoology and Conservation, University of Greifswald D-17489 Greifswald, Germany
| | - Marco A R Mello
- Department of General Biology, Federal University of Minas Gerais 31270-901 Belo Horizonte, MG, Brazil
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University Bozeman, Montana 59717 USA
| | - Sharon Swartz
- Department of Ecology and Evolutionary Biology and School of Engineering, Brown University Providence, Rhode Island 02912 USA
| | - Yossi Yovel
- Department of Zoology, Faculty of Life Sciences, and the "Sagol" School of Neuroscience, Tel-Aviv University Tel-Aviv, Israel
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Extracting Interactions between Flying Bat Pairs Using Model-Free Methods. ENTROPY 2019; 21:e21010042. [PMID: 33266758 PMCID: PMC7514148 DOI: 10.3390/e21010042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/15/2018] [Accepted: 01/03/2019] [Indexed: 12/03/2022]
Abstract
Social animals exhibit collective behavior whereby they negotiate to reach an agreement, such as the coordination of group motion. Bats are unique among most social animals, since they use active sensory echolocation by emitting ultrasonic waves and sensing echoes to navigate. Bats’ use of active sensing may result in acoustic interference from peers, driving different behavior when they fly together rather than alone. The present study explores quantitative methods that can be used to understand whether bats flying in pairs move independently of each other or interact. The study used field data from bats in flight and is based on the assumption that interactions between two bats are evidenced in their flight patterns. To quantify pairwise interaction, we defined the strength of coupling using model-free methods from dynamical systems and information theory. We used a control condition to eliminate similarities in flight path due to environmental geometry. Our research question is whether these data-driven methods identify directed coupling between bats from their flight paths and, if so, whether the results are consistent between methods. Results demonstrate evidence of information exchange between flying bat pairs, and, in particular, we find significant evidence of rear-to-front coupling in bats’ turning behavior when they fly in the absence of obstacles.
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Petzold JM, Alves-Gomes JA, Smith GT. Chirping and asymmetric jamming avoidance responses in the electric fish Distocyclus conirostris. ACTA ACUST UNITED AC 2018; 221:jeb.178913. [PMID: 30012575 DOI: 10.1242/jeb.178913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 07/11/2018] [Indexed: 11/20/2022]
Abstract
Electrosensory systems of weakly electric fish must accommodate competing demands of sensing the environment (electrolocation) and receiving social information (electrocommunication). The jamming avoidance response (JAR) is a behavioral strategy thought to reduce electrosensory interference from conspecific signals close in frequency. We used playback experiments to characterize electric organ discharge frequency (EODf), chirping behavior and the JAR of Distocyclus conirostris, a gregarious electric fish species. EODs of D. conirostris had low frequencies (∼80-200 Hz) that shifted in response to playback stimuli. Fish consistently lowered EODf in response to higher-frequency stimuli but inconsistently raised or lowered EODf in response to lower-frequency stimuli. This led to jamming avoidance or anti-jamming avoidance, respectively. We compare these behaviors with those of closely related electric fish (Eigenmannia and Sternopygus) and suggest that the JAR may have additional social functions and may not solely minimize the deleterious effects of jamming, as its name suggests.
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Affiliation(s)
- Jacquelyn M Petzold
- Department of Biology, Indiana University, 1001 E. 3rd St., Bloomington, IN 47405, USA.,Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave., Bloomington, IN 47405, USA
| | - José A Alves-Gomes
- Laboratório de Fisiologia Comportamental e Evolução (LFCE), Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, AM 69083-000, Brazil
| | - G Troy Smith
- Department of Biology, Indiana University, 1001 E. 3rd St., Bloomington, IN 47405, USA .,Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave., Bloomington, IN 47405, USA
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Penone C, Kerbiriou C, Julien JF, Marmet J, Le Viol I. Body size information in large-scale acoustic bat databases. PeerJ 2018; 6:e5370. [PMID: 30155347 PMCID: PMC6110253 DOI: 10.7717/peerj.5370] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 07/13/2018] [Indexed: 12/03/2022] Open
Abstract
Background Citizen monitoring programs using acoustic data have been useful for detecting population and community patterns. However, they have rarely been used to study broad scale patterns of species traits. We assessed the potential of acoustic data to detect broad scale patterns in body size. We compared geographical patterns in body size with acoustic signals in the bat species Pipistrellus pipistrellus. Given the correlation between body size and acoustic characteristics, we expected to see similar results when analyzing the relationships of body size and acoustic signals with climatic variables. Methods We assessed body size using forearm length measurements of 1,359 bats, captured by mist nets in France. For acoustic analyses, we used an extensive dataset collected through the French citizen bat survey. We isolated each bat echolocation call (n = 4,783) and performed automatic measures of signals, including the frequency of the flattest part of the calls (characteristic frequency). We then examined the relationship between forearm length, characteristic frequencies, and two components resulting from principal component analysis for geographic (latitude, longitude) and climatic variables. Results Forearm length was positively correlated with higher precipitation, lower seasonality, and lower temperatures. Lower characteristic frequencies (i.e., larger body size) were mostly related to lower temperatures and northern latitudes. While conducted on different datasets, the two analyses provided congruent results. Discussion Acoustic data from citizen science programs can thus be useful for the detection of large-scale patterns in body size. This first analysis offers a new perspective for the use of large acoustic databases to explore biological patterns and to address both theoretical and applied questions.
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Affiliation(s)
- Caterina Penone
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Christian Kerbiriou
- CESCO UMR7204 MNHN-UPMC-CNRS-Sorbonne Université, Université Pierre et Marie Curie (Paris VI), Paris, France.,Marine Station, Muséum national d'Histoire naturelle, Concarneau, France
| | - Jean-François Julien
- CESCO UMR7204 MNHN-UPMC-CNRS-Sorbonne Université, Muséum national d'Histoire naturelle, Paris, France
| | - Julie Marmet
- CESCO UMR7204 MNHN-UPMC-CNRS-Sorbonne Université, Muséum national d'Histoire naturelle, Paris, France
| | - Isabelle Le Viol
- Marine Station, Muséum national d'Histoire naturelle, Concarneau, France.,CESCO UMR7204 MNHN-UPMC-CNRS-Sorbonne Université, Muséum national d'Histoire naturelle, Paris, France
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40
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Jones TK, Wohlgemuth MJ, Conner WE. Active acoustic interference elicits echolocation changes in heterospecific bats. ACTA ACUST UNITED AC 2018; 221:jeb.176511. [PMID: 29950451 DOI: 10.1242/jeb.176511] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 06/14/2018] [Indexed: 11/20/2022]
Abstract
Echolocating bats often forage in the presence of both conspecific and heterospecific individuals, which have the potential to produce acoustic interference. Recent studies have shown that at least one bat species, the Brazilian free-tailed bat (Tadarida brasiliensis), produces specialized social signals that disrupt the sonar of conspecific competitors. We herein discuss the differences between passive and active jamming signals and test whether heterospecific jamming occurs in species overlapping spatiotemporally, as well as whether such interference elicits a jamming avoidance response. We compare the capture rates of tethered moths and the echolocation parameters of big brown bats (Eptesicus fuscus) challenged with the playback of the jamming signal normally produced by Brazilian free-tailed bats and playback of deconstructed versions of this signal. There were no differences in the capture rates of targets with and without the jamming signal, although significant changes in both spectral and temporal features of the bats' echolocation were observed. These changes are consistent with improvements of the signal-to-noise ratio in the presence of acoustic interference. Accordingly, we propose to expand the traditional definition of the jamming avoidance response, stating that echolocation changes in response to interference should decrease similarity between the two signals, to include any change that increases the ability to separate returning echoes from active jamming stimuli originating from conspecific and heterospecific organisms. Flexibility in echolocation is an important characteristic for overcoming various forms of acoustic interference and may serve a purpose in interspecific interactions as well as intraspecific ones.
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Affiliation(s)
- Te K Jones
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Melville J Wohlgemuth
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - William E Conner
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
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41
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Recording animal vocalizations from a UAV: bat echolocation during roost re-entry. Sci Rep 2018; 8:7779. [PMID: 29773821 PMCID: PMC5958051 DOI: 10.1038/s41598-018-26122-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/04/2018] [Indexed: 11/19/2022] Open
Abstract
Unmanned aerial vehicles (UAVs) are rising in popularity for wildlife monitoring, but direct recordings of animal vocalizations have not yet been accomplished, likely due to the noise generated by the UAV. Echolocating bats, especially Tadarida brasiliensis, are good candidates for UAV recording due to their high-speed, high-altitude flight. Here, we use a UAV to record the signals of bats during morning roost re-entry. We designed a UAV to block the noise of the propellers from the receiving microphone, and report on the characteristics of bioacoustic recordings from a UAV. We report the first published characteristics of echolocation signals from bats during group flight and cave re-entry. We found changes in inter-individual time-frequency shape, suggesting that bats may use differences in call design when sensing in complex groups. Furthermore, our first documented successful recordings of animals in their natural habitat demonstrate that UAVs can be important tools for bioacoustic monitoring, and we discuss the ethical considerations for such monitoring.
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42
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Hase K, Kadoya Y, Maitani Y, Miyamoto T, Kobayasi KI, Hiryu S. Bats enhance their call identities to solve the cocktail party problem. Commun Biol 2018; 1:39. [PMID: 30271924 PMCID: PMC6123623 DOI: 10.1038/s42003-018-0045-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 04/04/2018] [Indexed: 11/21/2022] Open
Abstract
Echolocating bats need to solve the problem of signal jamming by conspecifics when they are in a group. However, while several mechanisms have been suggested, it remains unclear how bats avoid confusion between their own echoes and interfering sounds in a complex acoustic environment. Here, we fixed on-board microphones onto individual frequency-modulating bats flying in groups. We found that group members broaden the inter-individual differences in the terminal frequencies of pulses, thereby decreasing the similarity of pulses among individuals. To understand what features most affect similarity between pulses, we calculated the similarity of signals mimicking pulses. We found that the similarity between those artificial signals was decreased most by manipulation of terminal frequency. These results demonstrate that the signal jamming problem is solved by this simple strategy, which may be universally used by animals that use active sensing, such as echolocating bats and electric fish, thereby transcending species and sensory modalities.
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Affiliation(s)
- Kazuma Hase
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto, 610-0321, Japan.
- Research Fellow of Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo, 102-0083, Japan.
| | - Yukimi Kadoya
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto, 610-0321, Japan
| | - Yosuke Maitani
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto, 610-0321, Japan
| | - Takara Miyamoto
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto, 610-0321, Japan
| | - Kohta I Kobayasi
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto, 610-0321, Japan
| | - Shizuko Hiryu
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara miyakodani, Kyotanabe, Kyoto, 610-0321, Japan.
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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43
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Thaler L, De Vos R, Kish D, Antoniou M, Baker C, Hornikx M. Human echolocators adjust loudness and number of clicks for detection of reflectors at various azimuth angles. Proc Biol Sci 2018; 285:20172735. [PMID: 29491173 PMCID: PMC5832709 DOI: 10.1098/rspb.2017.2735] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/06/2018] [Indexed: 11/15/2022] Open
Abstract
In bats it has been shown that they adjust their emissions to situational demands. Here we report similar findings for human echolocation. We asked eight blind expert echolocators to detect reflectors positioned at various azimuth angles. The same 17.5 cm diameter circular reflector placed at 100 cm distance at 0°, 45° or 90° with respect to straight ahead was detected with 100% accuracy, but performance dropped to approximately 80% when it was placed at 135° (i.e. somewhat behind) and to chance levels (50%) when placed at 180° (i.e. right behind). This can be explained based on poorer target ensonification owing to the beam pattern of human mouth clicks. Importantly, analyses of sound recordings show that echolocators increased loudness and numbers of clicks for reflectors at farther angles. Echolocators were able to reliably detect reflectors when level differences between echo and emission were as low as -27 dB, which is much lower than expected based on previous work. Increasing intensity and numbers of clicks improves signal-to-noise ratio and in this way compensates for weaker target reflections. Our results are, to our knowledge, the first to show that human echolocation experts adjust their emissions to improve sensory sampling. An implication from our findings is that human echolocators accumulate information from multiple samples.
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Affiliation(s)
- L Thaler
- Department of Psychology, Durham University, Science Site, South Road, Durham DH1 3LE, UK
| | - R De Vos
- Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - D Kish
- World Access for the Blind, Placentia 92870, CA, USA
| | - M Antoniou
- Department of Electronic Electrical and Systems Engineering, School of Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - C Baker
- Department of Electronic Electrical and Systems Engineering, School of Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - M Hornikx
- Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
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44
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Acoustic Sensors for Air and Surface Navigation Applications. SENSORS 2018; 18:s18020499. [PMID: 29414894 PMCID: PMC5855873 DOI: 10.3390/s18020499] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 11/16/2022]
Abstract
This paper presents the state-of-the-art and reviews the state-of-research of acoustic sensors used for a variety of navigation and guidance applications on air and surface vehicles. In particular, this paper focuses on echolocation, which is widely utilized in nature by certain mammals (e.g., cetaceans and bats). Although acoustic sensors have been extensively adopted in various engineering applications, their use in navigation and guidance systems is yet to be fully exploited. This technology has clear potential for applications in air and surface navigation/guidance for Intelligent Transport Systems (ITS), especially considering air and surface operations indoors and in other environments where satellite positioning is not available. Propagation of sound in the atmosphere is discussed in detail, with all potential attenuation sources taken into account. The errors introduced in echolocation measurements due to Doppler, multipath and atmospheric effects are discussed, and an uncertainty analysis method is presented for ranging error budget prediction in acoustic navigation applications. Considering the design challenges associated with monostatic and multi-static sensor implementations and looking at the performance predictions for different possible configurations, acoustic sensors show clear promises in navigation, proximity sensing, as well as obstacle detection and tracking. The integration of acoustic sensors in multi-sensor navigation systems is also considered towards the end of the paper and a low Size, Weight and Power, and Cost (SWaP-C) sensor integration architecture is presented for possible introduction in air and surface navigation systems.
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Russo D, Ancillotto L, Jones G. Bats are still not birds in the digital era: echolocation call variation and why it matters for bat species identification. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0089] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The recording and analysis of echolocation calls are fundamental methods used to study bat distribution, ecology, and behavior. However, the goal of identifying bats in flight from their echolocation calls is not always possible. Unlike bird songs, bat calls show large variation that often makes identification challenging. The problem has not been fully overcome by modern digital-based hardware and software for bat call recording and analysis. Besides providing fundamental insights into bat physiology, ecology, and behavior, a better understanding of call variation is therefore crucial to best recognize limits and perspectives of call classification. We provide a comprehensive overview of sources of interspecific and intraspecific echolocation call variations, illustrating its adaptive significance and highlighting gaps in knowledge. We remark that further research is needed to better comprehend call variation and control for it more effectively in sound analysis. Despite the state-of-art technology in this field, combining acoustic surveys with capture and roost search, as well as limiting identification to species with distinctive calls, still represent the safest way of conducting bat surveys.
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Affiliation(s)
- Danilo Russo
- Wildlife Research Unit, Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, Italy
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Leonardo Ancillotto
- Wildlife Research Unit, Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, Italy
| | - Gareth Jones
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom
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46
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Holderied MW, Thomas LA, Korine C. Ultrasound avoidance by flying antlions (Myrmeleontidae). J Exp Biol 2018; 221:jeb.189308. [DOI: 10.1242/jeb.189308] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/04/2018] [Indexed: 11/20/2022]
Abstract
The acoustic arms race between insectivorous bats and their invertebrate prey has led to the convergent evolution of ultrasound hearing in seven orders of nocturnal insects. Upon hearing the echolocation calls of an approaching bat such insects take defensive action. Here we document an unknown sense of ultrasound hearing and phonotactic flight behaviour in the neuropteran family Myrmeleontidae (antlions). The antlion Myrmeleon hyalinus was presented with sound pulses at ultrasonic frequencies used by echolocating bats and its response thresholds in tethered flight determined. Behaviours included abdominal twitches, wing-flicks, brief pauses in flight and flight cessation. Such behaviours create erratic evasive flight manoeuvres in other eared insects, particularly mantids and lacewings. Antlions responded best to ultrasound between 60-80 kHz (75 dB peSPL at 80 kHz) showing response thresholds similar to the related lacewings (Neuroptera, Chrysopidae). Yet at lower ultrasonic frequencies (20-50 kHz) antlions were far less sensitive than lacewings. Based on calculated response distances we conclude that antlions respond only after having been detected by bats rather than using early evasive flights. We argue that the high response threshold for low frequency ultrasound is adaptive for an insect that is mainly active close to and within vegetation, because a behavioural response to the lower ultrasonic frequencies used by high-flying bats would result in evasive action in the absence of actual predation risk.
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Affiliation(s)
- Marc W. Holderied
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Ave, Bristol, BS8 1TH, UK
| | - Liam A. Thomas
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Ave, Bristol, BS8 1TH, UK
| | - Carmi Korine
- The Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, 8499000, Israel
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47
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Corcoran AJ, Moss CF. Sensing in a noisy world: lessons from auditory specialists, echolocating bats. J Exp Biol 2017; 220:4554-4566. [DOI: 10.1242/jeb.163063] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
All animals face the essential task of extracting biologically meaningful sensory information from the ‘noisy’ backdrop of their environments. Here, we examine mechanisms used by echolocating bats to localize objects, track small prey and communicate in complex and noisy acoustic environments. Bats actively control and coordinate both the emission and reception of sound stimuli through integrated sensory and motor mechanisms that have evolved together over tens of millions of years. We discuss how bats behave in different ecological scenarios, including detecting and discriminating target echoes from background objects, minimizing acoustic interference from competing conspecifics and overcoming insect noise. Bats tackle these problems by deploying a remarkable array of auditory behaviors, sometimes in combination with the use of other senses. Behavioral strategies such as ceasing sonar call production and active jamming of the signals of competitors provide further insight into the capabilities and limitations of echolocation. We relate these findings to the broader topic of how animals extract relevant sensory information in noisy environments. While bats have highly refined abilities for operating under noisy conditions, they face the same challenges encountered by many other species. We propose that the specialized sensory mechanisms identified in bats are likely to occur in analogous systems across the animal kingdom.
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Affiliation(s)
- Aaron J. Corcoran
- Department of Biology, Wake Forest University, Box 7325 Reynolda Station, Winston-Salem, NC 27109, USA
| | - Cynthia F. Moss
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
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48
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Perkins ML, Frank HK, Pauly JM, Hadly EA. Frequency shifting reduces but does not eliminate acoustic interference between echolocating bats: A theoretical analysis. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:2133. [PMID: 29092549 DOI: 10.1121/1.5006928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Bats have been observed to shift the frequency of their echolocation calls in the presence of other echolocating bats, ostensibly as a way to reduce acoustic interference. Few studies, however, have examined the theoretical efficacy of such jamming avoidance responses. The present study uses the wideband ambiguity function to analyze the effects of acoustic interference from conspecifics and congeneric heterospecifics on the target acquisition ability of Myotis californicus and Myotis yumanensis, specifically whether unilateral or bilateral frequency shifts reduce the effects of such interference. Model results suggest that in conspecific interactions, M. yumanensis recovers its target acquisition ability more completely and with less absolute frequency shift than does M. californicus, but that alternative methods of jamming avoidance may be easier to implement. The optimal strategy for reducing heterospecific interference is for M. californicus to downshift its call and M. yumanensis to upshift its call, which exaggerates a preexisting difference in mean frequency between the calls of the two species. Further empirical research would elucidate whether these species do in practice actively employ frequency shifting or other means for jamming avoidance, as well as illuminate the role of acoustic interference in niche partitioning.
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Affiliation(s)
- Melinda L Perkins
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Hannah K Frank
- Department of Biology, Stanford University, Stanford, California 94305, USA
| | - John M Pauly
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Elizabeth A Hadly
- Department of Biology, Stanford University, Stanford, California 94305, USA
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49
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Echolocating bats rely on audiovocal feedback to adapt sonar signal design. Proc Natl Acad Sci U S A 2017; 114:10978-10983. [PMID: 28973851 DOI: 10.1073/pnas.1711892114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many species of bat emit acoustic signals and use information carried by echoes reflecting from nearby objects to navigate and forage. It is widely documented that echolocating bats adjust the features of sonar calls in response to echo feedback; however, it remains unknown whether audiovocal feedback contributes to sonar call design. Audiovocal feedback refers to the monitoring of one's own vocalizations during call production and has been intensively studied in nonecholocating animals. Audiovocal feedback not only is a necessary component of vocal learning but also guides the control of the spectro-temporal structure of vocalizations. Here, we show that audiovocal feedback is directly involved in the echolocating bat's control of sonar call features. As big brown bats tracked targets from a stationary position, we played acoustic jamming signals, simulating calls of another bat, timed to selectively perturb audiovocal feedback or echo feedback. We found that the bats exhibited the largest call-frequency adjustments when the jamming signals occurred during vocal production. By contrast, bats did not show sonar call-frequency adjustments when the jamming signals coincided with the arrival of target echoes. Furthermore, bats rapidly adapted sonar call design in the first vocalization following the jamming signal, revealing a response latency in the range of 66 to 94 ms. Thus, bats, like songbirds and humans, rely on audiovocal feedback to structure sonar signal design.
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50
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Greenfield MD, Marin-Cudraz T, Party V. Evolution of synchronies in insect choruses. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx096] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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