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Pedersen MB, Egenhardt M, Beedholm K, Skalshøi MR, Uebel AS, Hubancheva A, Koseva K, Moss CF, Luo J, Stidsholt L, Madsen PT. Superfast Lombard response in free-flying, echolocating bats. Curr Biol 2024; 34:2509-2516.e3. [PMID: 38744283 DOI: 10.1016/j.cub.2024.04.048] [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: 02/21/2024] [Revised: 03/20/2024] [Accepted: 04/22/2024] [Indexed: 05/16/2024]
Abstract
Acoustic cues are crucial to communication, navigation, and foraging in many animals, which hence face the problem of detecting and discriminating these cues in fluctuating noise levels from natural or anthropogenic sources. Such auditory dynamics are perhaps most extreme for echolocating bats that navigate and hunt prey on the wing in darkness by listening for weak echo returns from their powerful calls in complex, self-generated umwelts.1,2 Due to high absorption of ultrasound in air and fast flight speeds, bats operate with short prey detection ranges and dynamic sensory volumes,3 leading us to hypothesize that bats employ superfast vocal-motor adjustments to rapidly changing sensory scenes. To test this hypothesis, we investigated the onset and offset times and magnitude of the Lombard response in free-flying echolocating greater mouse-eared bats exposed to onsets of intense constant or duty-cycled masking noise during a landing task. We found that the bats invoked a bandwidth-dependent Lombard response of 0.1-0.2 dB per dB increase in noise, with very short delay and relapse times of 20 ms in response to onsets and termination of duty-cycled noise. In concert with the absence call time-locking to noise-free periods, these results show that free-flying bats exhibit a superfast, but hard-wired, vocal-motor response to increased noise levels. We posit that this reflex is mediated by simple closed-loop audio-motor feedback circuits that operate independently of wingbeat and respiration cycles to allow for rapid adjustments to the highly dynamic auditory scenes encountered by these small predators.
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Affiliation(s)
| | - Martin Egenhardt
- Section for Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Kristian Beedholm
- Section for Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | | | - Astrid Særmark Uebel
- Section for Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Antoniya Hubancheva
- Acoustic and Functional Ecology, Max Planck Institute for Biological Intelligence, 82319 Seewiesen, Germany; National Museum of Natural History, Bulgarian Academy of Sciences, 1000 Sofia, Bulgaria
| | - Kaloyana Koseva
- Section for Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Cynthia F Moss
- Department of Psychological and Brain Sciences, Departments of Neuroscience and Mechanical Engineering, Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jinhong Luo
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Laura Stidsholt
- Section for Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark; Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany
| | - Peter Teglberg Madsen
- Section for Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
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2
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Haarsma AJ, Jongejans E, Duijm E, van der Graaf C, Lammers Y, Sharma M, Siepel H, Gravendeel B. Female pond bats hunt in other areas than males and consume lighter prey when pregnant. J Mammal 2023; 104:1191-1204. [PMID: 38059006 PMCID: PMC10697422 DOI: 10.1093/jmammal/gyad096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 09/07/2023] [Indexed: 12/08/2023] Open
Abstract
Animals with large energy requirements are forced to optimize their hunting strategy, which may result in differentiation of the diet between sexes and across seasons. Here, we examined spatiotemporal variation in the diet of both sexes of the Pond Bat Myotis dasycneme, a species known to have spatial segregation of sexes when the young are born and lactating. Fecal pellets were collected from live animals for a period of 15 years at various locations in the Netherlands. A total of 535 pellets were successfully analyzed by microscopy and an additional 160 pellets by DNA metabarcoding. Morphological and molecular analyses showed that the diet of pregnant and lactating pond bats differed significantly from the diet of females with no reproductive investment. Further analyses of the data showed that pregnant female pond bats are highly dependent on small prey and pupae, mainly nonbiting midges and mosquitoes (Diptera: Chironomidae and Culicidae). These insects can be found in large quantities in peatlands intersected with shallow waterways, the habitat type in which female pond bats were observed more often than males. Our results suggest that during pregnancy the spatial segregation of sexes coincides with sex-specific diets, which might reflect habitat selection based on energy requirements, in addition to lowered intraspecific competition.
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Affiliation(s)
- Anne-Jifke Haarsma
- Radboud University, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
- Naturalis Biodiversity Center, Evolutionary Ecology Group, Darwinweg 2, 2333 CR Leiden, The Netherlands
| | - Eelke Jongejans
- Radboud University, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
- Netherlands Institute of Ecology, Department of Animal Ecology, Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Elza Duijm
- Naturalis Biodiversity Center, Evolutionary Ecology Group, Darwinweg 2, 2333 CR Leiden, The Netherlands
| | - Carolien van der Graaf
- Bat Research Consultancy Vroegvlieger, Ellekomstraat 70, 2573 XG Den Haag, The Netherlands
| | - Youri Lammers
- Naturalis Biodiversity Center, Evolutionary Ecology Group, Darwinweg 2, 2333 CR Leiden, The Netherlands
| | - Milan Sharma
- Naturalis Biodiversity Center, Evolutionary Ecology Group, Darwinweg 2, 2333 CR Leiden, The Netherlands
- HZ University of Applied Sciences, Life Sciences cluster, Edisonweg 4, 4382 NW Vlissingen, The Netherlands
| | - Henk Siepel
- Radboud University, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Barbara Gravendeel
- Radboud University, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
- Naturalis Biodiversity Center, Evolutionary Ecology Group, Darwinweg 2, 2333 CR Leiden, The Netherlands
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3
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Abstract
Animals must encode fundamental physical relationships in their brains. A heron plunging its head underwater to skewer a fish must correct for light refraction, an archerfish shooting down an insect must "consider" gravity, and an echolocating bat that is attacking prey must account for the speed of sound in order to assess its distance. Do animals learn these relations or are they encoded innately and can they adjust them as adults are all open questions. We addressed this question by shifting the speed of sound and assessing the sensory behavior of a bat species that naturally experiences different speeds of sound. We found that both newborn pups and adults are unable to adjust to this shift, suggesting that the speed of sound is innately encoded in the bat brain. Moreover, our results suggest that bats encode the world in terms of time and do not translate time into distance. Our results shed light on the evolution of innate and flexible sensory perception.
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Stidsholt L, Müller R, Beedholm K, Ma H, Johnson M, Madsen PT. Energy compensation and received echo level dynamics in constant-frequency bats during active target approaches. ACTA ACUST UNITED AC 2020; 223:jeb.217109. [PMID: 31836651 DOI: 10.1242/jeb.217109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/05/2019] [Indexed: 11/20/2022]
Abstract
Bats have been reported to adjust the energy of their outgoing vocalizations to target range (R) in a logarithmic fashion close to 20log10 R which has been interpreted as providing one-way compensation for increasing echo levels during target approaches. However, it remains unknown how species using high-frequency calls, which are strongly affected by absorption, adjust their vocal outputs during approaches to point targets. We hypothesized that such species should compensate less than the 20log10 R model predicts at longer distances and more at shorter distances as a consequence of the significant influence of absorption at longer ranges. Using a microphone array and an acoustic recording tag, we show that the output adjustments of two Hipposideros pratti and one Hipposideros armiger do not decrease logarithmically during approaches to different-sized targets. Consequently, received echo levels increase dramatically early in the approach phase with near-constant output levels, but level off late in the approach phase as a result of substantial output reductions. To improve echo-to-noise ratio, we suggest that bats using higher frequency vocalizations compensate less at longer ranges, where they are strongly affected by absorption. Close to the target, they decrease their output levels dramatically to mitigate reception of very high echo levels. This strategy maintains received echo levels between 6 and 40 dB re. 20 µPa2 s across different target sizes. The bats partially compensated for target size, but not in a one-to-one dB fashion, showing that these bats do not seek to stabilize perceived echo levels, but may instead use them to gauge target size.
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Affiliation(s)
- Laura Stidsholt
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Rolf Müller
- Department of Mechanical Engineering, 1075 Life Science Circle, Virginia Tech, Blacksburg, VA 24061, USA.,Shandong University-Virginia Tech International Laboratory, 27 Shanda South Road, Jinan, Shandong 250100, People's Republic of China
| | - Kristian Beedholm
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Hui Ma
- Shandong University-Virginia Tech International Laboratory, 27 Shanda South Road, Jinan, Shandong 250100, People's Republic of China
| | - Mark Johnson
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark.,Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 9LZ, Scotland, UK
| | - Peter Teglberg Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
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McKenzie NL, Bullen RD, Pennay M. Echolocation and foraging ecology of the bristle-faced free-tailed bat, Setirostris eleryi, in central Australia. AUSTRALIAN MAMMALOGY 2020. [DOI: 10.1071/am19038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We document the spectral characteristics of echolocation sequences of Setirostris eleryi recorded from riparian zones in the Central Ranges in Western Australia, near Warakurna. These are the first records of this species in Western Australia. The sequences are comparable to reference S. eleryi sequences from near Alice Springs, as well as to sequences from a nearby vouchered specimen locality (Hull River in the Northern Territory), yet distinct from Scotorepens greyii sequences from Western Australia, including locations in the Central Ranges. The central Australian S. eleryi sequences average 3kHz higher in frequency than reference S. eleryi recordings from eastern Australia. We deduce the species’ foraging strategy, microhabitat, wing beat frequency and flight speed from the echolocation sequences, then show that these deductions are consistent with calculations based on an airframe analysis of museum specimens, and with available field observations. The echolocation recordings provided a quick, passive, cost-effective characterisation of foraging niche, useful for conservation planning.
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The Skull Integration Pattern and Internal Constraints in Myotis myotis–Myotis blythii Species Group (Vespertilionidae, Chiroptera) Might be Shaped by Natural Selection During Evolution Along the Genetic Line of Least Resistance. Evol Biol 2019. [DOI: 10.1007/s11692-019-09488-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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McKenzie NL, Bullen RD. What can echolocation recordings reveal about the foraging ecology of Saccolaimus saccolaimus (Emballonuridae) in north-western Australia? AUST J ZOOL 2018. [DOI: 10.1071/zo19012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Echolocation sequences reveal aspects of the foraging ecology of Saccolaimus saccolaimus (Emballonuridae). In combination, pulse peak-frequency and fineness-of-tuning values derived from free-flying search-mode echolocation sequences emitted by S. saccolaimus in north-western Australia imply that it generally forages in uncluttered airspaces using an air superiority foraging strategy. Wing-beat frequency values, derived from pulse repetition rates in these sequences, reveal that it has a maximum aerobic level-flight speed of 8.1 m s–1 (used for foraging). These predictions are consistent with deductions based on airframe design parameters taken from museum specimens, and with available field observations. The echolocation recordings provided a quick, passive, cost-effective characterisation of foraging niche, useful for conservation planning.
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Bats pre-adapt sensory acquisition according to target distance prior to takeoff even in the presence of closer background objects. Sci Rep 2017; 7:467. [PMID: 28352130 PMCID: PMC5428694 DOI: 10.1038/s41598-017-00543-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/02/2017] [Indexed: 11/08/2022] Open
Abstract
Animals execute sensorimotor sequences to optimize performance of complex actions series. However, the sensory aspects of these sequences and their dynamic control are often poorly understood. We trained bats to fly to targets at different distances, and analysed their sensory behavior before and during flight to test whether they assess target distance before flight and how they adapt sensory acquisition in different situations. We demonstrate that bats’ sensory acquisition during approach-flight is more flexible than previously described. We identified acoustic parameters that illustrate that bats assess target distance before takeoff. We show that bats adapt their echolocation approach-sequences to target distance - ignoring closer background objects. At shorter distances, bats initiated their echolocation approach-sequence with distance-appropriate parameters, thus entering the approach sensory sequence “in step”. Our results suggest that in order to perform fine flight-manoeuvres, bats must maintain their sensorimotor plan in phase. To do this, they adapt acquisition according to target distance before initiating a complex sensory sequence based on a sensorimotor feedback-loop, even in complex acoustic environments, which impose other sensory reactions and restrictions. Though studying this in non-echolocating animals may prove difficult, such mechanisms are probably widely used in nature whenever complex series of sensorimotor actions are required.
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9
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Ciechanowski M, Zapart A, Kokurewicz T, Rusiński M, Lazarus M. Habitat selection of the pond bat (Myotis dasycneme) during pregnancy and lactation in northern Poland. J Mammal 2017. [DOI: 10.1093/jmammal/gyw108] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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10
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Vanderelst D, Steckel J, Boen A, Peremans H, Holderied MW. Place recognition using batlike sonar. eLife 2016; 5:e14188. [PMID: 27481189 PMCID: PMC4970868 DOI: 10.7554/elife.14188] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/20/2016] [Indexed: 11/28/2022] Open
Abstract
Echolocating bats have excellent spatial memory and are able to navigate to salient locations using bio-sonar. Navigating and route-following require animals to recognize places. Currently, it is mostly unknown how bats recognize places using echolocation. In this paper, we propose template based place recognition might underlie sonar-based navigation in bats. Under this hypothesis, bats recognize places by remembering their echo signature - rather than their 3D layout. Using a large body of ensonification data collected in three different habitats, we test the viability of this hypothesis assessing two critical properties of the proposed echo signatures: (1) they can be uniquely classified and (2) they vary continuously across space. Based on the results presented, we conclude that the proposed echo signatures satisfy both criteria. We discuss how these two properties of the echo signatures can support navigation and building a cognitive map.
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Affiliation(s)
- Dieter Vanderelst
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- Active Perception Lab, University of Antwerp, Antwerp, Belgium
| | - Jan Steckel
- Active Perception Lab, University of Antwerp, Antwerp, Belgium
- Constrained Systems Lab, Faculty of Applied Engineering, University of Antwerp, Antwerp, Belgium
| | - Andre Boen
- Active Perception Lab, University of Antwerp, Antwerp, Belgium
| | | | - Marc W Holderied
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
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11
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12
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Übernickel K, Simon R, Kalko EKV, Tschapka M. Sensory challenges for trawling bats: Finding transient prey on water surfaces. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2016; 139:1914. [PMID: 27106338 DOI: 10.1121/1.4944756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Bats are able to identify obstacles and prey objects based exclusively on acoustic information acquired via echolocation. To assess the echo information potentially available to the trawling bat Noctilio leporinus, prey objects were ensonified with artificial bat calls and deduced echo target strengths (TS) of the reflected signals. The artificial calls consisted either of constant frequency (CF) or frequency modulated (FM) sounds. Detection distances were calculated for call intensities of N. leporinus emitted in the field and in confined space. Measurements of a transient target consisting of a brief water splash and subsequently expanding water ripples revealed that concentrically expanding water ripples can provide sufficiently loud echoes to be detected by trawling bats. Experiments with stationary targets revealed differences in TS depending on the type of signal used (CF or FM). A calculated maximum detection distance between 4.5 and 13.7 m for all measured targets indicates that prey detection in this very loud calling species occurs much earlier than suggested by estimations based on modifications in echolocation or flight behavior.
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Affiliation(s)
- Kirstin Übernickel
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein-Allee 11, Ulm, Germany
| | - Ralph Simon
- Department of Sensor Technology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Elisabeth K V Kalko
- Institute of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, Ulm, Germany
| | - Marco Tschapka
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein-Allee 11, Ulm, Germany
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13
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Rowse EG, Harris S, Jones G. The Switch from Low-Pressure Sodium to Light Emitting Diodes Does Not Affect Bat Activity at Street Lights. PLoS One 2016; 11:e0150884. [PMID: 27008274 PMCID: PMC4805201 DOI: 10.1371/journal.pone.0150884] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 02/19/2016] [Indexed: 11/29/2022] Open
Abstract
We used a before-after-control-impact paired design to examine the effects of a switch from low-pressure sodium (LPS) to light emitting diode (LED) street lights on bat activity at twelve sites across southern England. LED lights produce broad spectrum ‘white’ light compared to LPS street lights that emit narrow spectrum, orange light. These spectral differences could influence the abundance of insects at street lights and thereby the activity of the bats that prey on them. Most of the bats flying around the LPS lights were aerial-hawking species, and the species composition of bats remained the same after the switch-over to LED. We found that the switch-over from LPS to LED street lights did not affect the activity (number of bat passes), or the proportion of passes containing feeding buzzes, of those bat species typically found in close proximity to street lights in suburban environments in Britain. This is encouraging from a conservation perspective as many existing street lights are being, or have been, switched to LED before the ecological consequences have been assessed. However, lighting of all spectra studied to date generally has a negative impact on several slow-flying bat species, and LED lights are rarely frequented by these ‘light-intolerant’ bat species.
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Affiliation(s)
- Elizabeth G Rowse
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Stephen Harris
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Gareth Jones
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
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14
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Aizpurua O, Alberdi A, Aihartza J, Garin I. Insight on how fishing bats discern prey and adjust their mechanic and sensorial features during the attack sequence. Sci Rep 2015; 5:12392. [PMID: 26196094 PMCID: PMC4508917 DOI: 10.1038/srep12392] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/26/2015] [Indexed: 11/26/2022] Open
Abstract
Several insectivorous bats have included fish in their diet, yet little is known about the processes underlying this trophic shift. We performed three field experiments with wild fishing bats to address how they manage to discern fish from insects and adapt their hunting technique to capture fish. We show that bats react only to targets protruding above the water and discern fish from insects based on prey disappearance patterns. Stationary fish trigger short and shallow dips and a terminal echolocation pattern with an important component of the narrowband and low frequency calls. When the fish disappears during the attack process, bats regulate their attack increasing the number of broadband and high frequency calls in the last phase of the echolocation as well as by lengthening and deepening their dips. These adjustments may allow bats to obtain more valuable sensorial information and to perform dips adjusted to the level of uncertainty on the location of the submerged prey. The observed ultrafast regulation may be essential for enabling fishing to become cost-effective in bats, and demonstrates the ability of bats to rapidly modify and synchronise their sensorial and motor features as a response to last minute stimulus variations.
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Affiliation(s)
- Ostaizka Aizpurua
- Department of Zoology and Animal Cell Biology. Faculty of Science and Technology. University of The Basque Country, UPV/EHU. Sarriena z.g., E-48940 Leioa, The Basque Country
| | - Antton Alberdi
- Department of Zoology and Animal Cell Biology. Faculty of Science and Technology. University of The Basque Country, UPV/EHU. Sarriena z.g., E-48940 Leioa, The Basque Country
| | - Joxerra Aihartza
- Department of Zoology and Animal Cell Biology. Faculty of Science and Technology. University of The Basque Country, UPV/EHU. Sarriena z.g., E-48940 Leioa, The Basque Country
| | - Inazio Garin
- Department of Zoology and Animal Cell Biology. Faculty of Science and Technology. University of The Basque Country, UPV/EHU. Sarriena z.g., E-48940 Leioa, The Basque Country
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15
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High-resolution GPS tracking reveals habitat selection and the potential for long-distance seed dispersal by Madagascan flying foxes Pteropus rufus. Glob Ecol Conserv 2015. [DOI: 10.1016/j.gecco.2015.02.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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16
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Aizpurua O, Aihartza J, Alberdi A, Baagøe HJ, Garin I. Fine-tuned echolocation and capture-flight of Myotis capaccinii when facing different-sized insect and fish prey. ACTA ACUST UNITED AC 2014; 217:3318-25. [PMID: 25013107 DOI: 10.1242/jeb.104992] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Formerly thought to be a strictly insectivorous trawling bat, recent studies have shown that Myotis capaccinii also preys on fish. To determine whether differences exist in bat flight behaviour, prey handling and echolocation characteristics when catching fish and insects of different size, we conducted a field experiment focused on the last stage of prey capture. We used synchronized video and ultrasound recordings to measure several flight and dip features as well as echolocation characteristics, focusing on terminal buzz phase I, characterized by a call rate exceeding 100 Hz, and buzz phase II, characterized by a drop in the fundamental well below 20 kHz and a repetition rate exceeding 150 Hz. When capturing insects, bats used both parts of the terminal phase to the same extent, and performed short and superficial drags on the water surface. In contrast, when preying on fish, buzz I was longer and buzz II shorter, and the bats made longer and deeper dips. These variations suggest that lengthening buzz I and shortening buzz II when fishing is beneficial, probably because buzz I gives better discrimination ability and the broader sonar beam provided by buzz II is useless when no evasive flight of the prey is expected. Additionally, bats continued emitting calls beyond the theoretical signal-overlap zone, suggesting that they might obtain information even when they have surpassed that threshold, at least initially. This study shows that M. capaccinii can regulate the temporal components of its feeding buzzes and modify prey capture technique according to the target.
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Affiliation(s)
- Ostaizka Aizpurua
- Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of The Basque Country, UPV/EHU, Sarriena z.g., E-48940 Leioa, The Basque Country, Spain
| | - Joxerra Aihartza
- Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of The Basque Country, UPV/EHU, Sarriena z.g., E-48940 Leioa, The Basque Country, Spain
| | - Antton Alberdi
- Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of The Basque Country, UPV/EHU, Sarriena z.g., E-48940 Leioa, The Basque Country, Spain
| | - Hans J Baagøe
- The Natural History Museum of Denmark, Zoological Museum, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Inazio Garin
- Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of The Basque Country, UPV/EHU, Sarriena z.g., E-48940 Leioa, The Basque Country, Spain
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17
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Wang L, Luo J, Wang H, Ou W, Jiang T, Liu Y, Lyle D, Feng J. Dynamic adjustment of echolocation pulse structure of big-footed myotis (Myotis macrodactylus) in response to different habitats. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2014; 135:928-932. [PMID: 25234900 DOI: 10.1121/1.4861232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Studying relationships between characteristics of sonar pulses and habitat clutter level is important for the understanding of signal design in bat echolocation. However, most studies have focused on overall spectral and temporal parameters of such vocalizations, with focus less on potential variation in frequency modulation rates (MRs) occurring within each pulse. In the current study, frequency modulation (FM) characteristics were examined in echolocation pulses recorded from big-footed myotis (Myotis macrodactylus) bats as these animals searched for prey in five habitats differing in relative clutter level. Pulses were analyzed using ten parameters, including four structure-related characters which were derived by dividing each pulse into three elements based on two knees in the FM sweep. Results showed that overall frequency, pulse duration, and MR all varied across habitat. The strongest effects were found for MR in the body of the pulse, implying that this particular component plays a major role as M. macrodactylus, and potentially other bat species, adjust to varying clutter levels in their foraging habitats.
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Affiliation(s)
- Lei Wang
- Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Jinhong Luo
- Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Hongna Wang
- Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Wei Ou
- Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Tinglei Jiang
- Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Ying Liu
- Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Dennis Lyle
- Department of Mechanical Engineering, Virginia Tech, Danville, Virginia 24540
| | - Jiang Feng
- Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
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Krüger F, Clare EL, Greif S, Siemers BM, Symondson WOC, Sommer RS. An integrative approach to detect subtle trophic niche differentiation in the sympatric trawling bat speciesMyotis dasycnemeandMyotis daubentonii. Mol Ecol 2013; 23:3657-71. [DOI: 10.1111/mec.12512] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/16/2013] [Accepted: 08/24/2013] [Indexed: 02/02/2023]
Affiliation(s)
- F. Krüger
- Ecology Centre, Landscape Ecology; University of Kiel; Olshausenstr. 75 24418 Kiel Germany
- Echolot Gbr; Eulerstr. 12 48155 Münster Germany
| | - E. L. Clare
- School of Biological and Chemical Sciences; Queen Mary University of London; Mile End Rd E1 4NS London UK
| | - S. Greif
- Max Planck Institute for Ornithology, Sensory Ecology; Eberhard-Gwinner-Straβe 4 82319 Seewiesen Germany
| | - B. M. Siemers
- Max Planck Institute for Ornithology, Sensory Ecology; Eberhard-Gwinner-Straβe 4 82319 Seewiesen Germany
| | - W. O. C. Symondson
- Cardiff School of Biosciences; Cardiff University; The Sir Martin Evans Building, Museum Avenue Cardiff CF10 3AX UK
| | - R. S. Sommer
- Ecology Centre, Landscape Ecology; University of Kiel; Olshausenstr. 75 24418 Kiel Germany
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Safi K, Kranstauber B, Weinzierl R, Griffin L, Rees EC, Cabot D, Cruz S, Proaño C, Takekawa JY, Newman SH, Waldenström J, Bengtsson D, Kays R, Wikelski M, Bohrer G. Flying with the wind: scale dependency of speed and direction measurements in modelling wind support in avian flight. MOVEMENT ECOLOGY 2013; 1:4. [PMID: 25709818 PMCID: PMC4337751 DOI: 10.1186/2051-3933-1-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 05/22/2013] [Indexed: 05/05/2023]
Abstract
BACKGROUND Understanding how environmental conditions, especially wind, influence birds' flight speeds is a prerequisite for understanding many important aspects of bird flight, including optimal migration strategies, navigation, and compensation for wind drift. Recent developments in tracking technology and the increased availability of data on large-scale weather patterns have made it possible to use path annotation to link the location of animals to environmental conditions such as wind speed and direction. However, there are various measures available for describing not only wind conditions but also the bird's flight direction and ground speed, and it is unclear which is best for determining the amount of wind support (the length of the wind vector in a bird's flight direction) and the influence of cross-winds (the length of the wind vector perpendicular to a bird's direction) throughout a bird's journey. RESULTS We compared relationships between cross-wind, wind support and bird movements, using path annotation derived from two different global weather reanalysis datasets and three different measures of direction and speed calculation for 288 individuals of nine bird species. Wind was a strong predictor of bird ground speed, explaining 10-66% of the variance, depending on species. Models using data from different weather sources gave qualitatively similar results; however, determining flight direction and speed from successive locations, even at short (15 min intervals), was inferior to using instantaneous GPS-based measures of speed and direction. Use of successive location data significantly underestimated the birds' ground and airspeed, and also resulted in mistaken associations between cross-winds, wind support, and their interactive effects, in relation to the birds' onward flight. CONCLUSIONS Wind has strong effects on bird flight, and combining GPS technology with path annotation of weather variables allows us to quantify these effects for understanding flight behaviour. The potentially strong influence of scaling effects must be considered and implemented in developing sampling regimes and data analysis.
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Affiliation(s)
- Kamran Safi
- />Department for Migration and Immuno-ecology, Max Plank Institute for Ornithology, Am Obstberg 1, 78315 Radolfzell, Germany
- />Department of Biology, University of Konstanz, Konstanz, 78464 Germany
| | - Bart Kranstauber
- />Department for Migration and Immuno-ecology, Max Plank Institute for Ornithology, Am Obstberg 1, 78315 Radolfzell, Germany
- />Department of Biology, University of Konstanz, Konstanz, 78464 Germany
| | | | - Larry Griffin
- />Wildfowl & Wetlands Trust, Slimbridge, Gloucestershire, GL2 7BT UK
| | - Eileen C Rees
- />Wildfowl & Wetlands Trust, Slimbridge, Gloucestershire, GL2 7BT UK
| | - David Cabot
- />Environmental Consultancy Services, White Strand, Killadoon, Louisburgh, Westport, Co. Mayo Ireland
| | - Sebastian Cruz
- />Department for Migration and Immuno-ecology, Max Plank Institute for Ornithology, Am Obstberg 1, 78315 Radolfzell, Germany
- />Department of Biology, University of Konstanz, Konstanz, 78464 Germany
| | - Carolina Proaño
- />Department for Migration and Immuno-ecology, Max Plank Institute for Ornithology, Am Obstberg 1, 78315 Radolfzell, Germany
- />Department of Biology, University of Konstanz, Konstanz, 78464 Germany
| | - John Y Takekawa
- />U.S. Geological Survey, Western Ecological Research Center, 505 Azuar Drive, Vallejo, CA 94592 USA
| | - Scott H Newman
- />Emergency Center for Transboundary Animal Diseases, Animal Production and Health Division, Food & Agriculture Organization of the United Nations, Rome, 00153 Italy
| | - Jonas Waldenström
- />Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Kalmar, SE-391 82 Sweden
| | - Daniel Bengtsson
- />Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Kalmar, SE-391 82 Sweden
| | - Roland Kays
- />School of Natural Resources, North Carolina State University, 3118 Jordan Hall, Raleigh, NC 27695 USA
- />North Carolina Museum of Natural Sciences, 11 West Jones St, Raleigh, NC 27601 USA
| | - Martin Wikelski
- />Department for Migration and Immuno-ecology, Max Plank Institute for Ornithology, Am Obstberg 1, 78315 Radolfzell, Germany
- />Department of Biology, University of Konstanz, Konstanz, 78464 Germany
| | - Gil Bohrer
- />Department of Civil, Environmental & Geodetic Engineering, The Ohio State University, Columbus, OH 43210 USA
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20
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Übernickel K, Tschapka M, Kalko EKV. Selective Eavesdropping Behaviour in Three Neotropical Bat Species. Ethology 2012. [DOI: 10.1111/eth.12038] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Almenar D, Aihartza J, Goiti U, Salsamendi E, Garin I. Hierarchical patch choice by an insectivorous bat through prey availability components. Behav Ecol Sociobiol 2012. [DOI: 10.1007/s00265-012-1451-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Ciechanowski M, Zapart A. The Diet of the Pond BatMyotis dasycnemeand Its Seasonal Variation in a Forested Lakeland of Northern Poland. ACTA CHIROPTEROLOGICA 2012. [DOI: 10.3161/150811012x654286] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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NORMAN ALEXP, TEAGLE LINDA, JONES GARETH. A METHOD FOR THE SYNCHRONISATION AND CONTROL OF ULTRASOUND RECORDING AND STEREOPHOTOGRAMMETRY IN THE RECONSTRUCTION OF ANIMAL FLIGHT. BIOACOUSTICS 2012. [DOI: 10.1080/09524622.1998.9753396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Norberg UML, Norberg RÅ. Scaling of wingbeat frequency with body mass in bats and limits to maximum bat size. J Exp Biol 2012; 215:711-22. [DOI: 10.1242/jeb.059865] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The ability to fly opens up ecological opportunities but flight mechanics and muscle energetics impose constraints, one of which is that the maximum body size must be kept below a rather low limit. The muscle power available for flight increases in proportion to flight muscle mass and wingbeat frequency. The maximum wingbeat frequency attainable among increasingly large animals decreases faster than the minimum frequency required, so eventually they coincide, thereby defining the maximum body mass at which the available power just matches up to the power required for sustained aerobic flight. Here, we report new wingbeat frequency data for 27 morphologically diverse bat species representing nine families, and additional data from the literature for another 38 species, together spanning a range from 2.0 to 870 g. For these species, wingbeat frequency decreases with increasing body mass as Mb–0.26. We filmed 25 of our 27 species in free flight outdoors, and for these the wingbeat frequency varies as Mb–0.30. These exponents are strikingly similar to the body mass dependency Mb–0.27 among birds, but the wingbeat frequency is higher in birds than in bats for any given body mass. The downstroke muscle mass is also a larger proportion of the body mass in birds. We applied these empirically based scaling functions for wingbeat frequency in bats to biomechanical theories about how the power required for flight and the power available converge as animal size increases. To this end we estimated the muscle mass-specific power required for the largest flying extant bird (12–16 kg) and assumed that the largest potential bat would exert similar muscle mass-specific power. Given the observed scaling of wingbeat frequency and the proportion of the body mass that is made up by flight muscles in birds and bats, we estimated the maximum potential body mass for bats to be 1.1–2.3 kg. The largest bats, extinct or extant, weigh 1.6 kg. This is within the range expected if it is the bat characteristic flight muscle mass and wingbeat frequency that limit the maximum body mass in bats. It is only a tenth the mass of the largest flying extant bird.
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Affiliation(s)
| | - R. Åke Norberg
- Department of Zoology, Göteborg University, Box 463, SE-405 30 Gothenburg, Sweden
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25
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High Trophic Similarity in the Sympatric North European Trawling Bat Species Myotis daubentonii and Myotis dasycneme. ACTA CHIROPTEROLOGICA 2012. [DOI: 10.3161/150811012x661666] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Parsons S, Riskin DK, Hermanson JW. Echolocation call production during aerial and terrestrial locomotion by New Zealand's enigmatic lesser short-tailed bat, Mystacina tuberculata. J Exp Biol 2010; 213:551-7. [DOI: 10.1242/jeb.039008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Linkage of echolocation call production with contraction of flight muscles has been suggested to reduce the energetic cost of flight with echolocation, such that the overall cost is approximately equal to that of flight alone. However, the pattern of call production with limb movement in terrestrially agile bats has never been investigated. We used synchronised high-speed video and audio recordings to determine patterns of association between echolocation call production and limb motion by Mystacina tuberculata Gray 1843 as individuals walked and flew, respectively. Results showed that there was no apparent linkage between call production and limb motion when bats walked. When in flight, two calls were produced per wingbeat, late in the downstroke and early in the upstroke. When bats walked, calls were produced at a higher rate, but at a slightly lower intensity, compared with bats in flight. These results suggest that M. tuberculata do not attempt to reduce the cost of terrestrial locomotion and call production through biomechanical linkage. They also suggest that the pattern of linkage seen when bats are in flight is not universal and that energetic savings cannot necessarily be explained by contraction of muscles associated with the downstroke alone.
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Affiliation(s)
- Stuart Parsons
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Daniel K. Riskin
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
- Department of Ecology and Evolutionary Biology, Brown University, Box G-B204, Providence, RI 02912, USA
| | - John W. Hermanson
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Grodzinski U, Spiegel O, Korine C, Holderied MW. Context-dependent flight speed: evidence for energetically optimal flight speed in the bat Pipistrellus kuhlii? J Anim Ecol 2009; 78:540-8. [PMID: 19243467 DOI: 10.1111/j.1365-2656.2009.01526.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
1. Understanding the causes and consequences of animal flight speed has long been a challenge in biology. Aerodynamic theory is used to predict the most economical flight speeds, minimizing energy expenditure either per distance (maximal range speed, Vmr) or per time (minimal power speed, Vmp). When foraging in flight, flight speed also affects prey encounter and energy intake rates. According to optimal flight speed theory, such effects may shift the energetically optimal foraging speed to above Vmp. 2. Therefore, we predicted that if energetic considerations indeed have a substantial effect on flight speed of aerial-hawking bats, they will use high speed (close to Vmr) to commute from their daily roost to the foraging sites, while a slower speed (but still above Vmp) will be preferred during foraging. To test these predictions, echolocation calls of commuting and foraging Pipistrellus kuhlii were recorded and their flight tracks were reconstructed using an acoustic flight path tracking system. 3. Confirming our qualitative prediction, commuting flight was found to be significantly faster than foraging flight (9.3 vs. 6.7 m s(-1)), even when controlling for its lower tortuosity. 4. In order to examine our quantitative prediction, we compared observed flight speeds with Vmp and Vmr values generated for the study population using two alternative aerodynamic models, based on mass and wing morphology variables measured from bats we captured while commuting. The Vmp and Vmr values generated by one of the models were much lower than our measured flight speed. According to the other model used, however, measured foraging flight was faster than Vmp and commuting flight slightly slower than Vmr, which is in agreement with the predictions of optimal flight speed theory. 5. Thus, the second aerodynamic model we used seems to be a reasonable predictor of the different flight speeds used by the bats while foraging and while commuting. This supports the hypothesis that bats fly at a context-dependent, energetically optimal flight speed.
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Affiliation(s)
- Uri Grodzinski
- Department of Zoology, Tel-Aviv University, Tel Aviv 69978, Israel
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29
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Effect of vegetation density on the use of trails by bats in a secondary tropical rain forest. JOURNAL OF TROPICAL ECOLOGY 2009. [DOI: 10.1017/s0266467408005671] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Natural forests are composed of a heterogeneous mixture of plant architectures that change temporally and spatially. In addition, variation in ridges, tree falls, natural clearing, logs and animal or man-made paths results in a topographic complexity which is likely to have a profound effect on the movements of animals within the forest.
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30
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Aihartza J, Almenar D, Salsamendi E, Goiti U, Garin I. Fishing behaviour in the long-fingered bat Myotis capaccinii (Bonaparte, 1837): an experimental approach. ACTA CHIROPTEROLOGICA 2008. [DOI: 10.3161/150811008x414863] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Melcón ML, Schnitzler HU, Denzinger A. Variability of the approach phase of landing echolocating Greater Mouse-eared bats. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2008; 195:69-77. [DOI: 10.1007/s00359-008-0383-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 10/09/2008] [Accepted: 10/19/2008] [Indexed: 10/21/2022]
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32
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Holderied MW, Baker CJ, Vespe M, Jones G. Understanding signal design during the pursuit of aerial insects by echolocating bats: tools and applications. Integr Comp Biol 2008; 48:74-84. [PMID: 21669774 DOI: 10.1093/icb/icn035] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bats are among the few predators that can exploit the large quantities of aerial insects active at night. They do this by using echolocation to detect, localize, and classify targets in the dark. Echolocation calls are shaped by natural selection to match ecological challenges. For example, bats flying in open habitats typically emit calls of long duration, with long pulse intervals, shallow frequency modulation, and containing low frequencies-all these are adaptations for long-range detection. As obstacles or prey are approached, call structure changes in predictable ways for several reasons: calls become shorter, thereby reducing overlap between pulse and echo, and calls change in shape in ways that minimize localization errors. At the same time, such changes are believed to support recognition of objects. Echolocation and flight are closely synchronized: we have monitored both features simultaneously by using stereo photogrammetry and videogrammetry, and by acoustic tracking of flight paths. These methods have allowed us to quantify the intensity of signals used by free-living bats, and illustrate systematic changes in signal design in relation to obstacle proximity. We show how signals emitted by aerial feeding bats can be among the most intense airborne sounds in nature. Wideband ambiguity functions developed in the processing of signals produce two-dimensional functions showing trade-offs between resolution of time and velocity, and illustrate costs and benefits associated with Doppler sensitivity and range resolution in echolocation. Remarkably, bats that emit broadband calls can adjust signal design so that Doppler-related overestimation of range compensates for underestimation of range caused by the bat's movement in flight. We show the potential of our methods for understanding interactions between echolocating bats and those prey that have evolved ears that detect bat calls.
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Affiliation(s)
- Marc W Holderied
- *School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG; Department of Electronic and Electrical Engineering, University College London, London WC1E 7JE, UK
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Schaub A, Schnitzler HU. Flight and echolocation behaviour of three vespertilionid bat species while commuting on flyways. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2007; 193:1185-94. [PMID: 17885759 DOI: 10.1007/s00359-007-0269-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Revised: 08/09/2007] [Accepted: 09/01/2007] [Indexed: 10/22/2022]
Abstract
This study compares the flight and echolocation behaviour of three vespertilionid bat species while they commute on flyways. We measured the bats' spatial position relative to vertical background contours and relative to the ground while recording their echolocation behaviour. In Myotis daubentonii, we found a significant influence of spatial context on the position and dimensions of flyways as well as on echolocation behaviour. In gap situations, flyways tended to be narrower and located closer to background structures, flight speeds were lower and the bandwidth of echolocation signals was larger than in edge situations. Differences in background structure did not affect flight and echolocation behaviour. When commuting in the same gap situation flyway positions and dimensions for M. daubentonii and Myotis brandtii were similar but differed from those of Pipistrellus pipistrellus, which were slightly higher and further out than those used by the Myotis species. In M. brandtii, flyway positions and dimensions remained constant over 3 years. We found species-dependent differences in signal structure, but pulse interval and flight speed were similar across all species. The influence of available space on the position of flyways, on flight speed and on echolocation behaviour is discussed.
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Affiliation(s)
- Andrea Schaub
- Tierphysiologie, Zoologisches Institut, Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
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34
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Abstract
Bat echolocation calls provide remarkable examples of 'good design' through evolution by natural selection. Theory developed from acoustics and sonar engineering permits a strong predictive basis for understanding echolocation performance. Call features, such as frequency, bandwidth, duration and pulse interval are all related to ecological niche. Recent technological breakthroughs have aided our understanding of adaptive aspects of call design in free-living bats. Stereo videogrammetry, laser scanning of habitat features and acoustic flight path tracking permit reconstruction of the flight paths of echolocating bats relative to obstacles and prey in nature. These methods show that echolocation calls are among the most intense airborne vocalizations produced by animals. Acoustic tracking has clarified how and why bats vary call structure in relation to flight speed. Bats using broadband echolocation calls adjust call design in a range-dependent manner so that nearby obstacles are localized accurately. Recent phylogenetic analyses based on gene sequences show that particular types of echolocation signals have evolved independently in several lineages of bats. Call design is often influenced more by perceptual challenges imposed by the environment than by phylogeny, and provides excellent examples of convergent evolution. Now that whole genome sequences of bats are imminent, understanding the functional genomics of echolocation will become a major challenge.
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Affiliation(s)
- Gareth Jones
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
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35
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Weinbeer M, Kalko EKV. Ecological niche and phylogeny: the highly complex echolocation behavior of the trawling long-legged bat, Macrophyllum macrophyllum. Behav Ecol Sociobiol 2007. [DOI: 10.1007/s00265-007-0364-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Russo D, Jones G, Arlettaz R. Echolocation and passive listening by foraging mouse-eared bats Myotis myotis and M. blythii. J Exp Biol 2007; 210:166-76. [PMID: 17170159 DOI: 10.1242/jeb.02644] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The two sibling mouse-eared bats, Myotis myotis and M. blythii, cope with similar orientation tasks, but separate their trophic niche by hunting in species-specific foraging microhabitats. Previous work has shown that both species rely largely on passive listening to detect and glean prey from substrates, and studies on other bat species have suggested that echolocation is `switched off' during passive listening. We tested the hypothesis that mouse-eared bats continuously emit echolocation calls while approaching prey. Echolocation may be needed for orientation while simultaneously listening for prey. Because these sibling species forage in different microhabitats and eat different prey, we also compared their echolocation behaviour and related it to their ecology. Both species used echolocation throughout prey approach, corroborating a functional role for echolocation during gleaning. Captive bats of both species emitted similar orientation calls, and pulse rate increased during prey approach. Between the search to approach phases, call amplitude showed a sudden, dramatic drop and bats adopted `whispering echolocation' by emitting weak calls. Whispering echolocation may reduce the risks of masking prey-generated sounds during passive listening, the mouse-eared bats' main detection tactic; it may also avoid alerting ultrasound-sensitive prey. In several cases M. myotisemitted a loud buzz made of 2-18 components when landing. We hypothesise that the buzz, absent in M. blythii at least when gleaning from the same substrate, is used to assess the distance from ground and refine the landing manoeuvre. Our findings have implications for niche separation between sibling species of echolocating bats, support a role for echolocation during passive listening and suggest a functional role for buzzes in landing control.
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Affiliation(s)
- Danilo Russo
- Laboratorio di Ecologia Applicata, Dipartimento Ar.Bo.Pa.Ve., Facoltà di Agraria, Università degli Studi di Napoli Federico II, via Università 100, I-80055 Portici (Napoli), Italy.
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Echolocation behavior of the bat Vespertilio murinus reveals the border between the habitat types “edge” and “open space”. Behav Ecol Sociobiol 2006. [DOI: 10.1007/s00265-006-0279-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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38
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Hadjisterkotis E. The destruction and conservation of the Egyptian Fruit bat Rousettus aegyptiacus in Cyprus: a historic review. EUR J WILDLIFE RES 2006. [DOI: 10.1007/s10344-006-0041-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Siemers BM, Baur E, Schnitzler HU. Acoustic mirror effect increases prey detection distance in trawling bats. Naturwissenschaften 2005; 92:272-6. [PMID: 15871000 DOI: 10.1007/s00114-005-0622-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Accepted: 02/21/2005] [Indexed: 10/25/2022]
Abstract
Many different and phylogenetically distant species of bats forage for insects above water bodies and take insects from and close to the surface; the so-called 'trawling behaviour'. Detection of surface-based prey by echolocation is facilitated by acoustically smooth backgrounds such as water surfaces that reflect sound impinging at an acute angle away from the bat and thereby render a prey object acoustically conspicuous. Previous measurements had shown that the echo amplitude of a target on a smooth surface is higher than that of the same target in mid-air, due to an acoustic mirror effect. In behavioural experiments with three pond bats (Myotis dasycneme), we tested the hypothesis that the maximum distances at which bats can detect prey are larger for prey on smooth surfaces than for the same prey in an airborne situation. We determined the moment of prey detection from a change in echolocation behaviour and measured the detection distance in 3D space from IR-video recordings using stereo-photogrammetry. The bats showed the predicted increase in detection distance for prey on smooth surfaces. The acoustic mirror effect therefore increases search efficiency and contributes to the acoustic advantages encountered by echolocating bats when foraging at low heights above smooth water surfaces. These acoustic advantages may have favoured the repeated evolution of trawling behaviour.
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Affiliation(s)
- Björn M Siemers
- Animal Physiology, Zoological Institute, Tübingen University, Auf der Morgenstelle 28, 72076, Tübingen, Germany.
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40
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Holderied MW, Korine C, Fenton MB, Parsons S, Robson S, Jones G. Echolocation call intensity in the aerial hawking bat Eptesicus bottae (Vespertilionidae) studied using stereo videogrammetry. J Exp Biol 2005; 208:1321-7. [PMID: 15781892 DOI: 10.1242/jeb.01528] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Aerial hawking bats use intense echolocation calls to search for insect prey. Their calls have evolved into the most intense airborne animal vocalisations. Yet our knowledge about call intensities in the field is restricted to a small number of species. We describe a novel stereo videogrammetry method used to study flight and echolocation behaviour, and to measure call source levels of the aerial hawking bat Eptesicus bottae(Vespertilionidae). Bats flew close to their predicted minimum power speed. Source level increased with call duration; the loudest call of E. bottae was at 133 dB peSPL. The calculated maximum detection distance for large flying objects (e.g. large prey, conspecifics) was up to 21 m. The corresponding maximum echo delay is almost exactly the duration of one wing beat in E. bottae and this also is its preferred pulse interval. These results, obtained by using videogrammetry to track bats in the field,corroborate earlier findings from other species from acoustic tracking methods.
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Affiliation(s)
- Marc W Holderied
- School of Biological Sciences, University of Bristol, Bristol, UK.
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Biscardi S, Orprecio J, Fenton MB, Tsoar A, Ratcliffe JM. Data, Sample Sizes and Statistics Affect the Recognition of Species of Bats by Their Echolocation Calls. ACTA CHIROPTEROLOGICA 2004. [DOI: 10.3161/001.006.0212] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Siemers BM, Schnitzler HU. Echolocation signals reflect niche differentiation in five sympatric congeneric bat species. Nature 2004; 429:657-61. [PMID: 15190352 DOI: 10.1038/nature02547] [Citation(s) in RCA: 255] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Accepted: 04/05/2004] [Indexed: 11/09/2022]
Abstract
Echolocating bats can be divided into guilds according to their preferred habitat and foraging behaviour, which coincide with distinct adaptations in wing morphology and structure of echolocation signals. Although coarse structuring of niche space between different guilds is generally accepted, it is not clear how niches differ within guilds, or whether there is fine-grained niche differentiation reflected in echolocation signal structure. Using a standardized performance test, here we show clutter-dependent differences in prey-capture success for bats from five species of European Myotis. These species are morphologically similar, sympatric, and all belong to the guild labelled "edge space aerial/trawling foragers". We further demonstrate a strong correlation between the prey-detection ability of the species and the respective search-call bandwidth. Our findings indicate that differences in echolocation signals contribute to within-guild niche differentiation. This is the first study relating sensory abilities of a set of potentially competing animal species to a direct measure of their respective foraging performance, suggesting an important role of sensory ecology in the structuring of animal communities.
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Affiliation(s)
- Björn M Siemers
- Animal Physiology, Zoological Institute, University of Tübingen, Morgenstelle 28, 72076 Tübingen, Germany.
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Sijpe MVD, Vandendriessche B, Voet P, Vandenberghe J, Duyck J, Naeyaert E, Manhaeve M, Martens E. Summer distribution of the Pond bat Myotis dasycneme (Chiroptera, Vespertilionidae) in the west of Flanders (Belgium) with regard to water quality. MAMMALIA 2004. [DOI: 10.1515/mamm.2004.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The summer distribution of the Pond bat
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Evidences of Piscivory by Myotis capaccinii (Bonaparte, 1837) in Southern Iberian Peninsula. ACTA CHIROPTEROLOGICA 2003. [DOI: 10.3161/001.005.0204] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Jones G, Webb PI, Sedgeley JA, O'Donnell CFJ. Mysterious Mystacina: how the New Zealand short-tailed bat(Mystacina tuberculata) locates insect prey. J Exp Biol 2003; 206:4209-16. [PMID: 14581591 DOI: 10.1242/jeb.00678] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The New Zealand short-tailed bat Mystacina tuberculata evolved in the absence of terrestrial mammals and initially with few potential predators. Unusual among bats, it is well adapted for the capture of prey on the ground. Bats from Fiordland, New Zealand had relatively low wing loadings and aspect ratios adapted for flight in cluttered habitats. We predicted that M. tuberculata would locate prey in air (uncluttered space) by echolocation. Echolocation call sequences associated with prey capture (terminal buzzes)were heard in the field, and bats detected and localized prey suspended on fishing line by echolocation in a flight cage. The bats emitted brief,multiharmonic echolocation calls at low duty cycle during search phase, and 64% of calls contained most energy in the fundamental harmonic. Approach- and terminal-phase calls were also broadband and multiharmonic. We predicted that bats would not use echolocation to locate prey hidden on the ground in leaf litter (cluttered space). Bats seemed unable to locate hidden prey precisely from the air and instead hunted for such prey while crawling. Echolocation calls were emitted at a low repetition rate on the ground, suggesting that here echolocation was used for orientation and not for prey detection. We experimentally removed cues available to the bats and showed that bats located mealworms in leaf litter by listening for prey-generated noises and possibly by olfaction.
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Affiliation(s)
- Gareth Jones
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
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Abstract
SUMMARYWingbeat frequency (fw) and amplitude(θw) were measured for 23 species of Australian bat,representing two sub-orders and six families. Maximum values were between 4 and 13 Hz for fw, and between 90 and 150° forθ w, depending on the species. Wingbeat frequency for each species was found to vary only slightly with flight speed over the lower half of the speed range. At high speeds, frequency is almost independent of velocity. Wingbeat frequency (Hz) depends on bat mass (m, kg) and flight speed (V, ms-1) according to the equation: fw=5.54-3.068log10m-2.857log10V. This simple relationship applies to both sub-orders and to all six families of bats studied. For 21 of the 23 species, the empirical values were within 1 Hz of the model values. One species, a small molossid, also had a second mode of flight in which fw was up to 3 Hz lower for all flight speeds.The following relationship predicts wingbeat amplitude to within±15° from flight speed and wing area (SREF,m2) at all flight speeds:θ w=56.92+5.18V+16.06log10SREF. This equation is based on data up to and including speeds that require maximum wingbeat amplitude to be sustained. For most species, the maximum wingbeat amplitude was 140°.
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Fenton MB, Bogdanowicz W. Relationships between external morphology and foraging behaviour: bats in the genusMyotis. CAN J ZOOL 2002. [DOI: 10.1139/z02-083] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A morphometric study of 41 species of Myotis revealed significant associations between morphological features and foraging styles, namely aerial feeding, gleaning, feeding over water, and trawling. Aerial feeders have small hind feet, short calcars, short ears, and narrow tragi. Gleaners have small hind feet, long ears, and wide tragi and tend to be larger in body size. Bats that feed over water have large hind feet, short calcars, short ears, and narrow tragi and tend to be smaller in body size. Trawlers have large hind feet and long calcars and tend to be larger in body size. The morphometric analysis also confirmed that some species of Myotis were intermediate in morphological features, coincid ing with alternation between foraging styles. The results support the view that the morphological features previously used to assign Myotis species to subgenera are more functional than phylogenetic, a position supported by recent genetic analyses. Examination of foraging styles from a phylogenetic perspective suggests that aerial feeding is ancestral and that subsequent diversification has been associated with partitioning and specialization into either gleaning or foraging over water and trawling. When the predictions from the multivariate analysis of the data for the genus Myotis are used with data from other bats, they suggest that 5 species of Nycteris are gleaners, while 11 species of Eptesicus are either aerial feeders or feed over water.
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Siemers BM, Stilz P, Schnitzler HU. The acoustic advantage of hunting at low heights above water: behavioural experiments on the European ‘trawling’ bats Myotis capaccinii, M. dasycneme and M. daubentonii. J Exp Biol 2001; 204:3843-54. [PMID: 11807102 DOI: 10.1242/jeb.204.22.3843] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
We have demonstrated in behavioural experiments that success in capturing prey from surfaces in ‘trawling Myotis’ (Leuconoë-type) depends on the acoustic properties of the surface on which the prey is presented. Two types of surface structure were ensonified with artificial bat signals to probe their acoustic characteristics. We have shown that perception of prey by echolocation is easier if the prey is presented on a smooth surface (such as calm water) than if it is presented on a structured surface (such as vegetation or the ground). This is because the smooth surface reflects a much lower level of clutter echoes than the structured one if ensonified at an angle typical for bats foraging low over water. The ensonification experiments revealed that the sound pressure level of the echo was even higher for mealworms on a smooth surface than for mealworms suspended in air. This might be because waves travelling via the surface also contribute to the echo (e.g. reflection from the surface to the mealworm, back to the surface and then to the receiver). From the behavioural experiments, we conclude that ‘trawling Myotis’ take isolated objects on smooth (water) surfaces for prey. Those objects reflect isolated, stationary acoustic glints back to the echolocating bats. Conversely, ‘trawling Myotis’ will not recognise prey if prey echoes are embedded in numerous clutter echoes. We have demonstrated marked similarities between the three European ‘trawling Myotis’ species M. dasycneme, M. daubentonii and M. capaccinii in echolocation behaviour, search image, foraging strategy and prey perception. We propose that a combination of prey abundance and acoustic advantages could have led to repeated and convergent evolution of ‘trawling’ bats in different parts of the world.
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Affiliation(s)
- B M Siemers
- Department of Animal Physiology, Zoological Institute, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
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