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Gong L, Wu H, Wang Z, Wu H, Feng J, Jiang T. Do nocturnal birds use acoustic and visual cues to avoid predation by bats? Integr Zool 2024; 19:524-537. [PMID: 37427486 DOI: 10.1111/1749-4877.12747] [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] [Indexed: 07/11/2023]
Abstract
Anti-predation strategies are critical to animal survival and are fundamental to deciphering predator-prey interactions. As an important defense strategy, sensory predator detection (such as through acoustic and visual cues) enables animals to assess predation risk and execute predator-avoidance behavior; however, there are limited studies on the anti-predation behavior of nocturnal animals. The prey of bats provides an excellent representative system for examining the anti-predation behavior of nocturnal animals. Here, we broadcasted different types of echolocation calls of the bird-eating bat Ia io to two wild passerine birds, namely, Zosterops japonicus and Sinosuthora webbiana, that are preyed upon by I. io, and presented the birds with individual bats under different light intensities. The results showed that both bird species were able to perceive the low-frequency audible portion of the bats' echolocation calls; however, they did not exhibit escape responses to the acoustic stimuli. In the dark and under moonlit conditions, both bird species were unable to respond to active bats at close range and the birds only exhibited evasive flight behavior when bats approached or touched them. These results suggest that nocturnal passerine birds may not be able to use acoustic or visual cues to detect bats and adopt evasive maneuvers to avoid predation. This work suggests that bat predation pressure may not elicit primary predator-avoidance responses in nocturnal passerine birds. The results provide new insights into the anti-predation behavior of nocturnal animals.
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Affiliation(s)
- Lixin Gong
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Huan Wu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Zhiqiang Wang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Hui Wu
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Tinglei Jiang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, Changchun, China
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2
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Lewanzik D, Ratcliffe JM, Etzler EA, Goerlitz HR, Jakobsen L. Stealth echolocation in aerial hawking bats reflects a substrate gleaning ancestry. Curr Biol 2023; 33:5208-5214.e3. [PMID: 37898121 DOI: 10.1016/j.cub.2023.10.014] [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: 09/01/2023] [Revised: 09/26/2023] [Accepted: 10/09/2023] [Indexed: 10/30/2023]
Abstract
Predator-prey co-evolution can escalate into an evolutionary arms race.1 Examples of insect countermeasures to bat echolocation are well-known,2 but presumptive direct counter strategies in bats to insect anti-bat tactics are rare. The emission of very low-intensity calls by the hawking Barbastella barbastellus to circumvent high-frequency moth hearing is the most convincing countermeasure known.2,3 However, we demonstrate that stealth echolocation did not evolve through a high-intensity aerial hawking ancestor becoming quiet as previously hypothesized2,3,4 but from a gleaning ancestor transitioning into an obligate aerial hawker. Our ancestral state reconstructions show that the Plecotini ancestor likely gleaned prey using low-intensity calls typical of gleaning bats and that this ability-and associated traits-was subsequently lost in the barbastelle lineage. Barbastelles did not, however, revert to the oral, high-intensity call emission that other hawking bats use but retained the low-intensity nasal emission of closely related gleaning plecotines despite an extremely limited echolocation range. We further show that barbastelles continue to emit low-intensity calls even under adverse noise conditions and do not broaden the echolocation beam during the terminal buzz, unlike other vespertilionids attacking airborne prey.5,6 Together, our results suggest that barbastelles' echolocation is subject to morphological constraints prohibiting higher call amplitudes and beam broadening in the terminal buzz. We suggest that an abundance of eared prey allowed the co-opting and maintenance of low-intensity, nasal echolocation in today's obligate hawking barbastelle and that this unique foraging behavior7 persists because barbastelles remain a rare, acoustically inconspicuous predator to eared moths. VIDEO ABSTRACT.
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Affiliation(s)
- Daniel Lewanzik
- Acoustic and Functional Ecology, Max Planck Institute for Biological Intelligence, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany; Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - John M Ratcliffe
- Department of Biology, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Erik A Etzler
- Department of Biology, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Holger R Goerlitz
- Acoustic and Functional Ecology, Max Planck Institute for Biological Intelligence, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany
| | - Lasse Jakobsen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
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3
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de Framond L, Beleyur T, Lewanzik D, Goerlitz HR. Calibrated microphone array recordings reveal that a gleaning bat emits low-intensity echolocation calls even in open-space habitat. J Exp Biol 2023; 226:jeb245801. [PMID: 37655585 PMCID: PMC10560550 DOI: 10.1242/jeb.245801] [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: 03/07/2023] [Accepted: 08/23/2023] [Indexed: 09/02/2023]
Abstract
Echolocating bats use ultrasound for orientation and prey capture in darkness. Ultrasound is strongly attenuated in air. Consequently, aerial-hawking bats generally emit very intense echolocation calls to maximize detection range. However, call levels vary more than tenfold (>20 dB) between species and are tightly linked to the foraging strategy. The brown long-eared bat (Plecotus auritus) is a primarily gleaning, low-amplitude species that may occasionally hawk airborne prey. We used state-of-the-art calibrated acoustic 3D-localization and automated call analysis to measure P. auritus' source levels. Plecotus auritus emits echolocation calls of low amplitude (92 dB rmsSPL re. 20 µPa at 10 cm) even while flying in open-space. While P. auritus thus probably benefits from delayed evasive manoeuvres of eared insects, we propose that low-amplitude echolocation did not evolve as an adaptive countermeasure, but is limited by morphological constraints.
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Affiliation(s)
- Léna de Framond
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany
| | - Thejasvi Beleyur
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany
| | - Daniel Lewanzik
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany
| | - Holger R. Goerlitz
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany
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4
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Ayala-Berdon J, Martínez Gómez M, Ponce AR, Beamonte-Barrientos R, Vázquez J, Rodriguez-Peña ON. Weather, ultrasonic, cranial and body traits predict insect diet hardness in a Central Mexican bat community. MAMMAL RES 2023. [DOI: 10.1007/s13364-023-00678-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
Abstract
AbstractInsectivorous bats exhibit food preferences for specific attributes in their prey. Hardness has been defined as an important prey attribute, and in some cases a limiting factor in foraging decisions for smaller compared to larger bat species. The goal of this study was to identify which factors influence the selection of prey hardness in a vespertilionid bat community. We investigated food consumed by bats by analyzing fecal samples obtained from eight bat species coexisting in a mountain ecosystem of central Mexico and correlate non-phylogenetically and phylogenetically prey hardness to weather, bat´s body, cranial and ultrasonic call structure variables. Results showed that diet of vespertilionid bats was mainly represented by Diptera, Neuroptera, Lepidoptera and Coleoptera consumption. The qualitative prey hardness index (From soft 1 to hard 5) ranked bats as: Myotis melanorhinus, Corynorhinus mexicanus, Myotis volans, Myotis californicus (< 3); Myotis velifer (< 4); Eptesicus fuscus, Idionycteris phyllotis and Myotis thysanodes (> 4.2). Prey hardness was positively correlated to minimum and mean temperatures, bat´s body weight, total and forearm lengths, cranial variables as: zygomatic breadth, mandibular length, height of the coronoid process, lower molar width, C-M3 superior and inferior rows length and upper molar width; and negatively to ultrasonic variables as total slope, call duration, low and high frequencies, band width and frequency maximum power. Considering phylogenies, prey hardness positively correlated to mandibular length, C-M3 inferior and superior rows lengths (p < 0.05). Our results showed that environmental, morphological and echolocation variables can be used as predictors of preferred insect prey in a community of vespertilionid bats.
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Bohenek JR, Pintar MR, Breech TM, Resetarits WJ. A wolf in sheep's clothing: Predatory fish have convergent consumptive effects but divergent predation‐risk effects. Ecosphere 2022. [DOI: 10.1002/ecs2.4073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Jason R. Bohenek
- Department of Biology and Center for Water and Wetlands Resources The University of Mississippi University Mississippi USA
| | - Matthew R. Pintar
- Department of Biology and Center for Water and Wetlands Resources The University of Mississippi University Mississippi USA
| | - Tyler M. Breech
- Department of Biology and Center for Water and Wetlands Resources The University of Mississippi University Mississippi USA
| | - William J. Resetarits
- Department of Biology and Center for Water and Wetlands Resources The University of Mississippi University Mississippi USA
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Silence and reduced echolocation during flight are associated with social behaviors in male hoary bats (Lasiurus cinereus). Sci Rep 2021; 11:18637. [PMID: 34545133 PMCID: PMC8452715 DOI: 10.1038/s41598-021-97628-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 08/27/2021] [Indexed: 11/23/2022] Open
Abstract
Bats are renowned for their sophisticated echolocation. However, recent research has indicated that bats may be less reliant on echolocation than has long been assumed. To test the hypothesis that bats reduce their use of echolocation to avoid eavesdropping by conspecifics, we deployed miniature tags that recorded ultrasound and accelerations on 10 wild hoary bats (Lasiurus cinereus) for one or two nights. This resulted in 997 10-s recordings. Bats switched between periods predominated by their typical high-intensity echolocation, or periods predominated by micro calls (unusually short, quiet calls), or no detectable calls (“silence”). Periods of high-intensity echolocation included high rates of feeding buzzes, whereas periods of micro calls and silence included high rates of social interactions with other bats. Bats switched back to high-intensity echolocation during actual social interactions. These data support the hypothesis that bats use reduced forms of echolocation and fly in silence to avoid eavesdropping from conspecifics, perhaps in the context of mating-related behavior. They also provide the strongest demonstration to date that bats fly for extended periods of time without the use of echolocation.
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7
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Olsen MN, Surlykke A, Jakobsen L. The sonar beam of Macrophyllum macrophyllum implies ecological adaptation under phylogenetic constraint. J Exp Biol 2020; 223:jeb223909. [PMID: 32398318 DOI: 10.1242/jeb.223909] [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: 02/24/2020] [Accepted: 05/05/2020] [Indexed: 11/20/2022]
Abstract
All animals are adapted to their ecology within the bounds of their evolutionary heritage. Echolocating bats clearly show such adaptations and boundaries through their biosonar call design. Adaptations include not only the overall time-frequency structure, but also the shape of the emitted echolocation beam. Macrophyllum macrophyllum is unique within the phyllostomid family, being the only species to predominantly hunt for insects in the open, on or above water, and as such it presents an interesting case for comparing the impact of phylogeny and ecology as it originates from a family of low-intensity, high-directionality gleaning bats, but occupies a niche dominated by very loud and substantially less-directional bats. Here, we examined the sonar beam pattern of M. macrophyllum in the field and in a flight room and compared it to closely related species with very different feeding ecology and to that of the niche-sharing but distantly related Myotis daubentonii Our results show that M. macrophyllum uses higher source levels and emits less-directional calls than other phyllostomids. In the field, its call directionality is comparable to M. daubentonii, but in the flight room, M. macrophyllum is substantially more directional. Hence our results indicate that ecology influences the emitted call, pushing the bats to emit a louder and broader beam than other phyllostomids, but that phylogeny does limit the emitted intensity and flexibility of the overall beam pattern.
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Affiliation(s)
| | - Annemarie Surlykke
- Department of Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Lasse Jakobsen
- Department of Biology, University of Southern Denmark, 5230 Odense, Denmark
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8
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Local-Scale Bat Guild Activity Differs with Rice Growth Stage at Ground Level in the Philippines. DIVERSITY 2019. [DOI: 10.3390/d11090148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
High-flying insectivorous bats, as wide-ranging generalist insectivores, are valuable consumers of high-altitude migrating pests of rice in Southeast Asia. Here, we documented the behavior of relatively low-flying bats over irrigated rice to elucidate their potential role as predators of rice-associated pest insects in the Philippines. Specifically, we tested the local-scale effects of rice stage, particularly seedling and late vegetative stages, and time of night on acoustic activity of bats foraging near ground level within three functional guilds (based on foraging distance from background clutter). We also monitored bat activity from two 50 m-high towers to assess the vertical extent of relatively low-flying guilds, as well as document high-flying bat guild presence and temporal behavior. At ground level, the most active guild biased their activity and feeding over early growth stage fields, but also foraged at tower level. Activity of the bat guild adept at foraging closest to vegetation did not vary with time of night or rice stage and was absent from tower recordings. High-flying bats were predictably rare at rice level, but exhibited high foraging intensity at 50 m. Given the well-documented, sequential arrival of insect guilds with growth stage, these data suggest that at ground level edge-space bats may be important consumers of detritivores (e.g., mosquitoes). Moreover, our data suggest that just as habitat heterogeneity enhances the services of arthropod predators, these management practices also enhance bat activity and, presumably, their contribution to pest suppression.
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9
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Hügel T, Goerlitz HR. Species‐specific strategies increase unpredictability of escape flight in eared moths. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Theresa Hügel
- Acoustic and Functional Ecology Group Max Planck Institute for Ornithology Seewiesen Germany
| | - Holger R. Goerlitz
- Acoustic and Functional Ecology Group Max Planck Institute for Ornithology Seewiesen Germany
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10
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Corcoran AJ, Weller TJ. Inconspicuous echolocation in hoary bats ( Lasiurus cinereus). Proc Biol Sci 2019; 285:rspb.2018.0441. [PMID: 29720417 DOI: 10.1098/rspb.2018.0441] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/10/2018] [Indexed: 01/05/2023] Open
Abstract
Echolocation allows bats to occupy diverse nocturnal niches. Bats almost always use echolocation, even when other sensory stimuli are available to guide navigation. Here, using arrays of calibrated infrared cameras and ultrasonic microphones, we demonstrate that hoary bats (Lasiurus cinereus) use previously unknown echolocation behaviours that challenge our current understanding of echolocation. We describe a novel call type ('micro' calls) that has three orders of magnitude less sound energy than other bat calls used in open habitats. We also document bats flying close to microphones (less than 3 m) without producing detectable echolocation calls. Acoustic modelling indicates that bats are not producing calls that exceed 70-75 dB at 0.1 m, a level that would have little or no known use for a bat flying in the open at speeds exceeding 7 m s-1 This indicates that hoary bats sometimes fly without echolocation. We speculate that bats reduce echolocation output to avoid eavesdropping by conspecifics during the mating season. These findings might partly explain why tens of thousands of hoary bats are killed by wind turbines each year. They also challenge the long-standing assumption that bats-model organisms for sensory specialization-are reliant on sonar for nocturnal navigation.
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Affiliation(s)
- Aaron J Corcoran
- Department of Biology, Wake Forest University, PO Box 7325, Reynolda Station, Winston-Salem, NC 27109, USA
| | - Theodore J Weller
- USDA Forest Service, Pacific Southwest Research Station, Arcata, CA 95521, USA
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11
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Gordon R, Ivens S, Ammerman LK, Fenton MB, Littlefair JE, Ratcliffe JM, Clare EL. Molecular diet analysis finds an insectivorous desert bat community dominated by resource sharing despite diverse echolocation and foraging strategies. Ecol Evol 2019; 9:3117-3129. [PMID: 30962885 PMCID: PMC6434550 DOI: 10.1002/ece3.4896] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 01/05/2023] Open
Abstract
Interspecific differences in traits can alter the relative niche use of species within the same environment. Bats provide an excellent model to study niche use because they use a wide variety of behavioral, acoustic, and morphological traits that may lead to multi-species, functional groups. Predatory bats have been classified by their foraging location (edge, clutter, open space), ability to use aerial hawking or substrate gleaning and echolocation call design and flexibility, all of which may dictate their prey use. For example, high frequency, broadband calls do not travel far but offer high object resolution while high intensity, low frequency calls travel further but provide lower resolution. Because these behaviors can be flexible, four behavioral categories have been proposed: (a) gleaning, (b) behaviorally flexible (gleaning and hawking), (c) clutter-tolerant hawking, and (d) open space hawking. Many recent studies of diet in bats use molecular tools to identify prey but mainly focus on one or two species in isolation; few studies provide evidence for substantial differences in prey use despite the many behavioral, acoustic, and morphological differences. Here, we analyze the diet of 17 sympatric species in the Chihuahuan desert and test the hypothesis that peak echolocation frequency and behavioral categories are linked to differences in diet. We find no significant correlation between dietary richness and echolocation peak frequency though it spanned close to 100 kHz across species. Our data, however, suggest that bats which use both gleaning and hawking strategies have the broadest diets and are most differentiated from clutter-tolerant aerial hawking species.
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Affiliation(s)
- Rowena Gordon
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
| | - Sally Ivens
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
| | | | - M. Brock Fenton
- Department of BiologyUniversity of Western OntarioLondonOntarioCanada
| | - Joanne E. Littlefair
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
- Department of BiologyMcGill UniversityMontréalQuébecCanada
| | - John M. Ratcliffe
- Department of BiologyUniversity of Toronto MississaugaMississaugaOntarioCanada
| | - Elizabeth L. Clare
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
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12
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Brown PE, Rainey WE. Bats of the California Channel Islands: New Records with New Methods. WEST N AM NATURALIST 2018. [DOI: 10.3398/064.078.0316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Gorresen PM, Brinck KW, DeLisle MA, Montoya-Aiona K, Pinzari CA, Bonaccorso FJ. Multi-state occupancy models of foraging habitat use by the Hawaiian hoary bat (Lasiurus cinereus semotus). PLoS One 2018; 13:e0205150. [PMID: 30379835 PMCID: PMC6209161 DOI: 10.1371/journal.pone.0205150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 09/20/2018] [Indexed: 11/19/2022] Open
Abstract
Multi-state occupancy modeling can often improve assessments of habitat use and site quality when animal activity or behavior data are available. We examine the use of the approach for evaluating foraging habitat suitability of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus) from classifications of site occupancy based on flight activity levels and feeding behavior. In addition, we used data from separate visual and auditory sources, namely thermal videography and acoustic (echolocation) detectors, jointly deployed at sample sites to compare the effectiveness of each method in the context of occupancy modeling. Video-derived observations demonstrated higher and more accurate estimates of the prevalence of high bat flight activity and feeding events than acoustic sampling methods. Elevated levels of acoustic activity by Hawaiian hoary bats were found to be related primarily to beetle biomass in this study. The approach may have a variety of applications in bat research, including inference about species-resource relationships, habitat quality and the extent to which species intensively use areas for activities such as foraging.
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Affiliation(s)
- P. Marcos Gorresen
- Hawai‘i Cooperative Studies Unit, University of Hawai‘i at Hilo, Hilo, Hawai‘i, United States of America
- * E-mail:
| | - Kevin W. Brinck
- Hawai‘i Cooperative Studies Unit, University of Hawai‘i at Hilo, Hilo, Hawai‘i, United States of America
| | - Megan A. DeLisle
- Hawai‘i Cooperative Studies Unit, University of Hawai‘i at Hilo, Hilo, Hawai‘i, United States of America
| | - Kristina Montoya-Aiona
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, Hawaii National Park, Hawai‘i, United States of America
| | - Corinna A. Pinzari
- Hawai‘i Cooperative Studies Unit, University of Hawai‘i at Hilo, Hilo, Hawai‘i, United States of America
| | - Frank J. Bonaccorso
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, Hawaii National Park, Hawai‘i, United States of America
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14
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Razak K. Adaptations for Substrate Gleaning in Bats: The Pallid Bat as a Case Study. BRAIN, BEHAVIOR AND EVOLUTION 2018; 91:97-108. [DOI: 10.1159/000488873] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/26/2018] [Indexed: 11/19/2022]
Abstract
Substrate gleaning is a foraging strategy in which bats use a mixture of echolocation, prey-generated sounds, and vision to localize and hunt surface-dwelling prey. Many substrate-gleaning species depend primarily on prey-generated noise to hunt. Use of echolocation is limited to general orientation and obstacle avoidance. This foraging strategy involves a different set of selective pressures on morphology, behavior, and auditory system organization of bats compared to the use of echolocation for both hunting and navigation. Gleaning likely evolved to hunt in cluttered environments and/or as a counterstrategy to reduce detection by eared prey. Gleaning bats simultaneously receive streams of echoes from obstacles and prey-generated noise, and have to segregate these acoustic streams to attend to one or both. Not only do these bats have to be exquisitely sensitive to the soft, low frequency sounds produced by walking/rustling prey, they also have to precisely localize these sounds. Gleaners typically use low intensity echolocation calls. Such stealth echolocation requires a nervous system that is attuned to low intensity sound processing. In addition, landing on the ground to hunt may bring gleaners in close proximity to venomous prey. In fact, at least 2 gleaning bat species are known to hunt highly venomous scorpions. While a number of studies have addressed adaptations for echolocation in bats that hunt in the air, very little is known about the morphological, behavioral, and neural specializations for gleaning in bats. This review highlights the novel insights gleaning bats provide into bat evolution, particularly auditory pathway organization and ion channel structure/function relationships. Gleaning bats are found in multiple families, suggesting convergent evolution of specializations for gleaning as a foraging strategy. However, most of this review is based on recent work on a single species – the pallid bat (Antrozous palli dus) – symptomatic of the fact that more comparative work is needed to identify the mechanisms that facilitate gleaning behavior.
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15
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Gordon SD, Ter Hofstede HM. The influence of bat echolocation call duration and timing on auditory encoding of predator distance in noctuoid moths. ACTA ACUST UNITED AC 2018; 221:221/6/jeb171561. [PMID: 29567831 DOI: 10.1242/jeb.171561] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/24/2018] [Indexed: 11/20/2022]
Abstract
Animals co-occur with multiple predators, making sensory systems that can encode information about diverse predators advantageous. Moths in the families Noctuidae and Erebidae have ears with two auditory receptor cells (A1 and A2) used to detect the echolocation calls of predatory bats. Bat communities contain species that vary in echolocation call duration, and the dynamic range of A1 is limited by the duration of sound, suggesting that A1 provides less information about bats with shorter echolocation calls. To test this hypothesis, we obtained intensity-response functions for both receptor cells across many moth species for sound pulse durations representing the range of echolocation call durations produced by bat species in northeastern North America. We found that the threshold and dynamic range of both cells varied with sound pulse duration. The number of A1 action potentials per sound pulse increases linearly with increasing amplitude for long-duration pulses, saturating near the A2 threshold. For short sound pulses, however, A1 saturates with only a few action potentials per pulse at amplitudes far lower than the A2 threshold for both single sound pulses and pulse sequences typical of searching or approaching bats. Neural adaptation was only evident in response to approaching bat sequences at high amplitudes, not search-phase sequences. These results show that, for short echolocation calls, a large range of sound levels cannot be coded by moth auditory receptor activity, resulting in no information about the distance of a bat, although differences in activity between ears might provide information about direction.
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Affiliation(s)
- Shira D Gordon
- Dartmouth College, Department of Biological Sciences, 78 College Street, Hanover, NH 03755, USA
| | - Hannah M Ter Hofstede
- Dartmouth College, Department of Biological Sciences, 78 College Street, Hanover, NH 03755, USA
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16
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Lewanzik D, Goerlitz HR. Continued source level reduction during attack in the low‐amplitude bat
Barbastella barbastellus
prevents moth evasive flight. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13073] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Daniel Lewanzik
- Acoustic and Functional Ecology GroupMax Planck Institute for Ornithology Seewiesen Germany
| | - Holger R. Goerlitz
- Acoustic and Functional Ecology GroupMax Planck Institute for Ornithology Seewiesen Germany
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