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Keicher L, Shipley JR, Dietzer MT, Wikelski M, Dechmann DKN. Heart rate monitoring reveals differential seasonal energetic trade-offs in male noctule bats. Proc Biol Sci 2024; 291:20240855. [PMID: 38981523 DOI: 10.1098/rspb.2024.0855] [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: 12/07/2023] [Accepted: 06/07/2024] [Indexed: 07/11/2024] Open
Abstract
Understanding how animals meet their daily energy requirements is critical in our rapidly changing world. Small organisms with high metabolic rates can conserve stored energy when food availability is low or increase energy intake when energetic requirements are high, but how they balance this in the wild remains largely unknown. Using miniaturized heart rate transmitters, we continuously quantified energy expenditure, torpor use and foraging behaviour of free-ranging male bats (Nyctalus noctula) in spring and summer. In spring, bats used torpor extensively, characterized by lowered heart rates and consequently low energy expenditures. In contrast, in summer, bats consistently avoided torpor, even though they could have used this low-energy mode. As a consequence, daytime heart rates in summer were three times as high compared with the heart rates in spring. Daily energy use increased by 42% during summer, despite lower thermogenesis costs at higher ambient temperatures. Likely, as a consequence, bats nearly doubled their foraging duration. Overall, our results indicate that summer torpor avoidance, beneficial for sperm production and self-maintenance, comes with a high energetic cost. The ability to identify and monitor such vulnerable energetic life-history stages is particularly important to predict how species will deal with increasing temperatures and changes in their resource landscapes.
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Affiliation(s)
- Lara Keicher
- Max Planck Institute of Animal Behavior, Am Obstberg 1 , Radolfzell 78315, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10 , Konstanz 78457, Germany
| | - J Ryan Shipley
- WLS Institute for Snow and Avalanche Research, Flüelastraße 11 , Davos CH-7260, Switzerland
| | - Melina T Dietzer
- Department of Wildlife Ecology and Management, Uni-ver-sity of Freiburg, Tennenbacher Straße 4 , Freiburg 79106, Germany
| | - Martin Wikelski
- Max Planck Institute of Animal Behavior, Am Obstberg 1 , Radolfzell 78315, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10 , Konstanz 78457, Germany
| | - Dina K N Dechmann
- Max Planck Institute of Animal Behavior, Am Obstberg 1 , Radolfzell 78315, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10 , Konstanz 78457, Germany
- Cluster for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10 , Konstanz 78457, Germany
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2
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Mundinger C, Wolf JM, Gogarten JF, Fierz M, Scheuerlein A, Kerth G. Artificially raised roost temperatures lead to larger body sizes in wild bats. Curr Biol 2023; 33:3977-3984.e4. [PMID: 37633280 DOI: 10.1016/j.cub.2023.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/13/2023] [Accepted: 08/01/2023] [Indexed: 08/28/2023]
Abstract
Climate warming has major consequences for animal populations, as ambient temperature profoundly influences all organisms' physiology, behavior, or both.1 Body size in many organisms has been found to change with increased ambient temperatures due to influences on metabolism and/or access to resources.2,3,4,5,6 Changes in body size, in turn, can affect the dynamics and persistence of populations.7 Notably, in some species, body size has increased over the last decades in response to warmer temperatures.3,8 This has primarily been attributed to higher food availability,3 but might also result from metabolic savings in warmer environments.9,10 Bechstein's bats (Myotis bechsteinii) grow to larger body sizes in warmer summers,11 which affects their demography as larger females reproduce earlier at the expense of a shorter life expectancy.12,13 However, it remains unclear whether larger body sizes in warmer summers were due to thermoregulatory benefits or due to increased food availability. To disentangle these effects, we artificially heated communal day roosts of wild maternity colonies over four reproductive seasons. We used generalized mixed models to analyze these experimental results along with 25 years of long-term data comprising a total of 741 juveniles. We found that individuals raised in heated roosts grew significantly larger than those raised in unheated conditions. This suggests that metabolic savings in warmer conditions lead to increased body size, potentially resulting in the decoupling of body growth from prey availability. Our study highlights a direct mechanism by which climate change may alter fitness-relevant traits, with potentially dire consequences for population persistence.
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Affiliation(s)
- Carolin Mundinger
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Loitzer Str. 26, 17489 Greifswald, Germany
| | - Janis M Wolf
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Loitzer Str. 26, 17489 Greifswald, Germany.
| | - Jan F Gogarten
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Loitzer Str. 26, 17489 Greifswald, Germany; Department of Pathogen Evolution, Helmholtz Institute for One Health, Helmholtz-Centre for Infection Research (HZI), Greifswald, Fleischmannstraße 42, 17489 Greifswald, Germany
| | - Marcel Fierz
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Alexander Scheuerlein
- Institute for Data Science, University of Greifswald, Felix-Hausdorff-Straße 18, 17489 Greifswald, Germany
| | - Gerald Kerth
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Loitzer Str. 26, 17489 Greifswald, Germany
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3
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Moosman PR, Marsh DM, Pody EK, Brust TJ. Differential selection of roosts by Eastern Small-footed Myotis ( Myotis leibii) relative to rock structure and microclimate. J Mammal 2023; 104:723-738. [PMID: 37545666 PMCID: PMC10399919 DOI: 10.1093/jmammal/gyad037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 02/27/2023] [Indexed: 08/08/2023] Open
Abstract
Roost selection by insectivorous bats in temperate regions is presumably influenced by roost microclimates in relation to thermoregulatory strategies, but few studies have included temperature measurements in habitat selection models. Rocky landscape features are an important source of roosts that provide both shelter from predators and beneficial microclimates for bats. Most information about rock-roosting bats has been derived from western North America. We studied microhabitat selection by the Eastern Small-footed Myotis (Myotis leibii) on natural talus slopes and human-made stone structures in the Appalachian Mountains of Virginia and New Hampshire, relative to thermal and structural characteristics of rock crevices. Roosts were located with a combination of radiotelemetry and randomized visual surveys. Roost-switching behavior and structural characteristics of roosts did not appear to be influenced by the methods we used to locate roosts. Compared to random crevices, both sexes selected crevices with narrow openings, likely to provide protection from predators. Reproductive females also selected rocks that were larger and more thermally stable than random crevices, whereas males selected crevices that were structurally similar to random crevices but warmed more during the day. Rock size and other structural characteristics influenced temperatures of roosts and random crevices alike by inhibiting excessive daytime heating and nighttime cooling. Because large rocks were important for reproductive females, and talus slopes with large rocks could be limited, we recommend including rock size as a variable in landscape scale habitat assessments for Eastern Small-footed Myotis. Protecting or managing for habitat features with large rocks that receive high solar exposure could benefit Eastern Small-footed Myotis, and perhaps other rock-roosting species.
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Affiliation(s)
- Paul R Moosman
- Department of Biology, Virginia Military Institute, Lexington, Virginia 24450, USA
| | - David M Marsh
- Department of Biology, Washington and Lee University, Lexington, Virginia 24450, USA
| | - Emily K Pody
- Department of Biology, Virginia Military Institute, Lexington, Virginia 24450, USA
- EDGE Engineering and Science, LLC, Houston, Texas 77084, USA
| | - Timothy J Brust
- Department of Biology, Virginia Military Institute, Lexington, Virginia 24450, USA
- EDGE Engineering and Science, LLC, Houston, Texas 77084, USA
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4
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Taub M, Mazar O, Yovel Y. Pregnancy-related sensory deficits might impair foraging in echolocating bats. BMC Biol 2023; 21:60. [PMID: 36973777 PMCID: PMC10044376 DOI: 10.1186/s12915-023-01557-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 03/02/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND Reproduction entails substantial demands throughout its distinct stages. The mammalian gestation period imposes various energetic costs and movement deficits, but its effects on the sensory system are poorly understood. Bats rely heavily on active sensing, using echolocation to forage in complete darkness, or when lighting is uncertain. We examined the effects of pregnancy on bat echolocation. RESULTS We show that pregnant Kuhl's pipistrelles (Pipistrellus kuhlii) altered their echolocation and flight behavior. Specifically, pregnant bats emitted longer echolocation signals at an ~ 15% lower rate, while flying more slowly and at a lower altitude compared to post-lactating females. A sensorimotor foraging model suggests that these changes could lead to an ~ 15% reduction in hunting performance during pregnancy. CONCLUSIONS Sensory deficits related to pregnancy could impair foraging in echolocating bats. Our study demonstrates an additional cost of reproduction of possible relevance to other sensory modalities and organisms.
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Affiliation(s)
- Mor Taub
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
| | - Omer Mazar
- Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Yossi Yovel
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
- Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel.
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5
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Stapelfeldt B, Tress C, Koch R, Tress J, Kerth G, Scheuerlein A. Long-term field study reveals that warmer summers lead to larger and longer-lived females only in northern populations of Natterer's bats. Oecologia 2023; 201:853-861. [PMID: 36773071 PMCID: PMC10038953 DOI: 10.1007/s00442-023-05318-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/07/2023] [Indexed: 02/12/2023]
Abstract
Animals often respond to climate change with changes in morphology, e.g., shrinking body size with increasing temperatures, as expected by Bergmann's rule. Because small body size can have fitness costs for individuals, this trend could threaten populations. Recent studies, however, show that morphological responses to climate change and the resulting fitness consequences cannot be generalized even among related species. In this long-term study, we investigate the interaction between ambient temperature, body size and survival probability in a large number of individually marked wild adult female Natterer's bats (Myotis nattereri). We compare populations from two geographical regions in Germany with a different climate. In a sliding window analysis, we found larger body sizes in adult females that were raised in warmer summers only in the northern population, but not in the southern population that experienced an overall warmer climate. With a capture-mark-recapture approach, we showed that larger individuals had higher survival rates, demonstrating that weather conditions in early life could have long-lasting fitness effects. The different responses in body size to warmer temperatures in the two regions highlight that fitness-relevant morphological responses to climate change have to be viewed on a regional scale and may affect local populations differently.
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Affiliation(s)
- Bianca Stapelfeldt
- Zoological Institute and Museum, University of Greifswald, Greifswald, Germany.
| | - Christoph Tress
- Fledermausforschungsprojekt Wooster Teerofen e.V., Wooster Teerofen, Germany
| | - Ralf Koch
- Naturpark Nossentiner/Schwinzer Heide, Plau am See OT Karow, Germany
| | - Johannes Tress
- Fledermausforschungsprojekt Wooster Teerofen e.V., Wooster Teerofen, Germany
| | - Gerald Kerth
- Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
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6
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Mundinger C, Fleischer T, Scheuerlein A, Kerth G. Global warming leads to larger bats with a faster life history pace in the long-lived Bechstein's bat (Myotis bechsteinii). Commun Biol 2022; 5:682. [PMID: 35810175 PMCID: PMC9271042 DOI: 10.1038/s42003-022-03611-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/21/2022] [Indexed: 01/22/2023] Open
Abstract
Whether species can cope with environmental change depends considerably on their life history. Bats have long lifespans and low reproductive rates which make them vulnerable to environmental changes. Global warming causes Bechstein’s bats (Myotis bechsteinii) to produce larger females that face a higher mortality risk. Here, we test whether these larger females are able to offset their elevated mortality risk by adopting a faster life history. We analysed an individual-based 25-year dataset from 331 RFID-tagged wild bats and combine genetic pedigrees with data on survival, reproduction and body size. We find that size-dependent fecundity and age at first reproduction drive the observed increase in mortality. Because larger females have an earlier onset of reproduction and shorter generation times, lifetime reproductive success remains remarkably stable across individuals with different body sizes. Our study demonstrates a rapid shift to a faster pace of life in a mammal with a slow life history. Warming summers across a 25-year study are linked to larger body sizes in female bats, leading to a switch from a slow-reproducing, long-lived species to a faster pace of life.
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Affiliation(s)
- Carolin Mundinger
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Loitzer Straße 26, 17489, Greifswald, Germany.
| | - Toni Fleischer
- Leipzig University Medical Center, Department of Psychiatry and Psychotherapy, Semmelweisstraße 10, 04103, Leipzig, Germany
| | - Alexander Scheuerlein
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Loitzer Straße 26, 17489, Greifswald, Germany
| | - Gerald Kerth
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Loitzer Straße 26, 17489, Greifswald, Germany
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7
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Smeltzer EA, Stead SM, Li MF, Samson D, Kumpan LT, Teichroeb JA. Social sleepers: The effects of social status on sleep in terrestrial mammals. Horm Behav 2022; 143:105181. [PMID: 35594742 DOI: 10.1016/j.yhbeh.2022.105181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 04/12/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022]
Abstract
Social status among group-living mammals can impact access to resources, such as water, food, social support, and mating opportunities, and this differential access to resources can have fitness consequences. Here, we propose that an animal's social status impacts their access to sleep opportunities, as social status may predict when an animal sleeps, where they sleep, who they sleep with, and how well they sleep. Our review of terrestrial mammals examines how sleep architecture and intensity may be impacted by (1) sleeping conditions and (2) the social experience during wakefulness. Sleeping positions vary in thermoregulatory properties, protection from predators, and exposure to parasites. Thus, if dominant individuals have priority of access to sleeping positions, they may benefit from higher quality sleeping conditions and, in turn, better sleep. With respect to waking experiences, we discuss the impacts of stress on sleep, as it has been established that specific social statuses can be characterized by stress-related physiological profiles. While much research has focused on how dominance hierarchies impact access to resources like food and mating opportunities, differential access to sleep opportunities among mammals has been largely ignored despite its potential fitness consequences.
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Affiliation(s)
- E A Smeltzer
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - S M Stead
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada.
| | - M F Li
- Department of Anthropology, University of Toronto, 19 Russell St., Toronto, Ontario M5S 2S2, Canada
| | - D Samson
- Department of Anthropology, University of Toronto Mississauga, 3359 Mississauga Rd., Mississauga, Ontario L5L 1C6, Canada
| | - L T Kumpan
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - J A Teichroeb
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
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8
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Kerth G. Long-term field studies in bat research: importance for basic and applied research questions in animal behavior. Behav Ecol Sociobiol 2022; 76:75. [PMID: 35669868 PMCID: PMC9135593 DOI: 10.1007/s00265-022-03180-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/06/2022] [Accepted: 05/11/2022] [Indexed: 11/26/2022]
Abstract
AbstractAnimal species differ considerably in longevity. Among mammals, short-lived species such as shrews have a maximum lifespan of about a year, whereas long-lived species such as whales can live for more than two centuries. Because of their slow pace of life, long-lived species are typically of high conservation concern and of special scientific interest. This applies not only to large mammals such as whales, but also to small-sized bats and mole-rats. To understand the typically complex social behavior of long-lived mammals and protect their threatened populations, field studies that cover substantial parts of a species’ maximum lifespan are required. However, long-term field studies on mammals are an exception because the collection of individualized data requires considerable resources over long time periods in species where individuals can live for decades. Field studies that span decades do not fit well in the current career and funding regime in science. This is unfortunate, as the existing long-term studies on mammals yielded exciting insights into animal behavior and contributed data important for protecting their populations. Here, I present results of long-term field studies on the behavior, demography, and life history of bats, with a particular focus on my long-term studies on wild Bechstein’s bats. I show that long-term studies on individually marked populations are invaluable to understand the social system of bats, investigate the causes and consequences of their extraordinary longevity, and assess their responses to changing environments with the aim to efficiently protect these unique mammals in the face of anthropogenic global change.
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Affiliation(s)
- Gerald Kerth
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, University of Greifswald, Greifswald, Germany
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9
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Perony N, Kerth G, Schweitzer F. Data-driven modelling of group formation in the fission-fusion dynamics of Bechstein's bats. J R Soc Interface 2022; 19:20220170. [PMID: 35506214 PMCID: PMC9065967 DOI: 10.1098/rsif.2022.0170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Communal roosting in Bechstein’s bat colonies is characterized by the formation of several groups that use different day roosts and that regularly dissolve and re-merge (fission–fusion dynamics). Analysing data from two colonies of different sizes over many years, we find that (i) the number of days that bats stay in the same roost before changing follows an exponential distribution that is independent of the colony size and (ii) the number and size of groups that bats formed for roosting depend on the size of the colony, such that above a critical colony size two to six groups of different sizes are formed. To model these two observations, we propose an agent-based model in which agents make their decisions about roosts based on both random and social influences. For the latter, they copy the roost preference of another agent which models the transfer of the respective information. Our model is able to reproduce both the distribution of stay length in the same roost and the emergence of groups of different sizes dependent on the colony size. Moreover, we are able to predict the critical system size at which the formation of different groups emerges without global coordination. We further comment on dynamics that bridge the roosting decisions on short time scales (less than 1 day) with the social structures observed at long time scales (more than 1 year).
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Affiliation(s)
- Nicolas Perony
- Chair of Systems Design, ETH Zurich, Weinbergstrasse 56/58, 8092 Zurich, Switzerland
| | - Gerald Kerth
- Applied Zoology and Nature Conservation, University of Greifswald, Loitzer Strasse 26, 17489 Greifswald, Germany
| | - Frank Schweitzer
- Chair of Systems Design, ETH Zurich, Weinbergstrasse 56/58, 8092 Zurich, Switzerland
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10
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Crawford RD, Dodd LE, Tillman FE, O’Keefe JM. Evaluating bat boxes: design and placement alter bioenergetic costs and overheating risk. CONSERVATION PHYSIOLOGY 2022; 10:coac027. [PMID: 35492416 PMCID: PMC9041549 DOI: 10.1093/conphys/coac027] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/18/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Bat box microclimates vary spatially and temporally in temperature suitability. This heterogeneity subjects roosting bats to a variety of thermoregulatory challenges (e.g. heat and cold stress). Understanding how different bat box designs, landscape placements, weather and bat use affect temperature suitability and energy expenditure is critical to promote safe and beneficial artificial roosting habitat for species of conservation concern. From April to September 2019, we systematically deployed 480 temperature dataloggers among 40 rocket box style bat boxes of 5 designs and regularly monitored bat abundance. We used bioenergetic models to assess energy costs for endothermic and heterothermic bats and modelled the overheating risk for each box as a function of design, placement, bat abundance and weather. For endothermic bats, predicted daily energy expenditure was lower for solar-exposed placements, large group sizes and a box design with enhanced thermal mass. For heterothermic bats, shaded landscape placements were the most energetically beneficial and bat box design was not important, because all designs generally offered microclimates suitable for torpor use at some position within the box. Overheating risk was highest for solar-exposed landscape placements and for designs lacking modifications to buffer temperature, and with increasing bat abundance, increasing ambient temperature and slower wind speeds. The external water jacket design, with the greatest thermal mass, concomitantly decreased overheating risk and endothermic energy expenditure. By assessing bat box suitability from two physiological perspectives, we provide a robust method to assess the conservation value of bat box design and placement strategies. We recommend future studies examine how changing thermal mass and conductance can be used to diminish overheating risk while also enhancing the effects of social thermoregulation for bat box users.
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Affiliation(s)
- Reed D Crawford
- Corresponding author: Program in Ecology, Evolution, and Conservation Biology, W-503 Turner Hall, 1102 S. Goodwin Ave, Urbana, IL 61801, USA. Tel: 812-242-0117.
| | - Luke E Dodd
- Department of Biological Sciences, Eastern Kentucky University, Kentucky 40475, USA
| | - Francis E Tillman
- Center for Bat Research, Outreach, and Conservation, Indiana State University, Indiana 47809, USA
- Department of Biological Sciences, The University of Memphis, Tennessee 38152, USA
| | - Joy M O’Keefe
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Illinois 61801, USA
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Illinois 61801, USA
- Center for Bat Research, Outreach, and Conservation, Indiana State University, Indiana 47809, USA
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11
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Alston JM, Dillon ME, Keinath DA, Abernethy IM, Goheen JR. Daily torpor reduces the energetic consequences of microhabitat selection for a widespread bat. Ecology 2022; 103:e3677. [PMID: 35262926 PMCID: PMC9286574 DOI: 10.1002/ecy.3677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 12/16/2021] [Indexed: 11/25/2022]
Abstract
Homeothermy requires increased metabolic rates as temperatures decline below the thermoneutral zone, so homeotherms typically select microhabitats within or near their thermoneutral zones during periods of inactivity. However, many mammals and birds are heterotherms that relax internal controls on body temperature and go into torpor when maintaining a high, stable body temperature, which is energetically costly. Such heterotherms should be less tied to microhabitats near their thermoneutral zones and, because heterotherms spend more time in torpor and expend less energy at colder temperatures, heterotherms may even select microhabitats in which temperatures are well below their thermoneutral zones. We studied how temperature and daily torpor influence the selection of microhabitats (i.e., diurnal roosts) by a heterothermic bat (Myotis thysanodes). We (1) quantified the relationship between ambient temperature and daily duration of torpor, (2) simulated daily energy expenditure over a range of microhabitat temperatures, and (3) quantified the influence of microhabitat temperature on microhabitat selection. In addition, warm microhabitats substantially reduced the energy expenditure of simulated homeothermic bats, and heterothermic bats modulated their use of daily torpor to maintain a constant level of energy expenditure across microhabitats of different temperatures. Daily torpor expanded the range of energetically economical microhabitats, such that microhabitat selection was independent of microhabitat temperature. Our work adds to a growing literature documenting the functions of torpor beyond its historical conceptualization as a last‐resort measure to save energy during periods of extended or acute energetic stress.
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Affiliation(s)
- Jesse M Alston
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA.,Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming, USA.,Center for Advanced Systems Understanding (CASUS), Görlitz, DEU, Germany
| | - Michael E Dillon
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Douglas A Keinath
- Wyoming Ecological Services Field Office, United States Fish and Wildlife Service, Cheyenne, Wyoming, USA
| | - Ian M Abernethy
- Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming, USA
| | - Jacob R Goheen
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
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12
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Stapelfeldt B, Scheuerlein A, Tress C, Koch R, Tress J, Kerth G. Precipitation during two weeks in spring influences reproductive success of first-year females in the long-lived Natterer's bat. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211881. [PMID: 35223067 PMCID: PMC8847888 DOI: 10.1098/rsos.211881] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/07/2022] [Indexed: 05/03/2023]
Abstract
Bats are characterized by low reproductive rates in contrast with most of other small mammals. This makes their populations vulnerable when inclement environmental conditions such as cold and rainy weather impair the reproductive success of females. The fine-scale effect of weather on bats, however, remains largely unknown. Using a sliding window analysis approach on an 18-year individualized dataset on six Natterer's bat (Myotis nattereri) colonies, we investigated the effect of fine-scale weather conditions on age-specific reproductive success. We found that increased precipitation during a short time window in spring strongly reduced the probability of successful reproduction of first-year (FY) females. Our data suggest that this time window is concomitant with implantation or early pregnancy, before substantial investment into embryo development. In addition, larger FY had higher reproductive success, suggesting that reproduction may be condition dependent in young females. Reproductive success of older females was not affected by either weather or individual parameters. Our results show that changes in precipitation pattern may compromise the reproductive success of FY females. Further studies are needed to better understand the impact of weather conditions on reproductive success in long-lived bats under climate change scenarios.
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Affiliation(s)
- Bianca Stapelfeldt
- Universität Greifswald Zoologisches Institut und Museum, Greifswald Mecklenburg-Vorpommern, Germany
| | - Alexander Scheuerlein
- Universität Greifswald Zoologisches Institut und Museum, Greifswald Mecklenburg-Vorpommern, Germany
| | | | - Ralf Koch
- Naturpark Nossentiner/Schwinzer Heide, Germany
| | - Johannes Tress
- Fledermausforschungsprojekt Wooster Teerofen e.V., Germany
| | - Gerald Kerth
- Universität Greifswald Zoologisches Institut und Museum, Greifswald Mecklenburg-Vorpommern, Germany
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13
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Bakken GS, Tillman FE, O'Keefe JM. Methods for assessing artificial thermal refuges: Spatiotemporal analysis more informative than averages. J Therm Biol 2021; 105:103150. [DOI: 10.1016/j.jtherbio.2021.103150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
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14
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Mundinger C, Scheuerlein A, Kerth G. Long-term study shows that increasing body size in response to warmer summers is associated with a higher mortality risk in a long-lived bat species. Proc Biol Sci 2021; 288:20210508. [PMID: 34074120 PMCID: PMC8170209 DOI: 10.1098/rspb.2021.0508] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/10/2021] [Indexed: 12/27/2022] Open
Abstract
Change in body size is one of the universal responses to global warming, with most species becoming smaller. While small size in most species corresponds to low individual fitness, small species typically show high population growth rates in cross-species comparisons. It is unclear, therefore, how climate-induced changes in body size ultimately affect population persistence. Unravelling the relationship between body size, ambient temperature and individual survival is especially important for the conservation of endangered long-lived mammals such as bats. Using an individual-based 24-year dataset from four free-ranging Bechstein's bat colonies (Myotis bechsteinii), we show for the first time a link between warmer summer temperatures, larger body sizes and increased mortality risk. Our data reveal a crucial time window in June-July, when juveniles grow to larger body sizes in warmer conditions. Body size is also affected by colony size, with larger colonies raising larger offspring. At the same time, larger bats have higher mortality risks throughout their lives. Our results highlight the importance of understanding the link between warmer weather and body size as a fitness-relevant trait for predicting species-specific extinction risks as consequences of global warming.
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Affiliation(s)
- Carolin Mundinger
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
| | - Alexander Scheuerlein
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
| | - Gerald Kerth
- Applied Zoology and Nature Conservation, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
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15
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Hsu C, Kao M, Chou C, Cheng H, Liu J. Tests of hypotheses for group formation in the subtropical leaf-dwelling bat, Kerivoula furva. Ecol Evol 2021; 11:6730-6741. [PMID: 34141253 PMCID: PMC8207392 DOI: 10.1002/ece3.7524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/06/2021] [Accepted: 03/19/2021] [Indexed: 11/07/2022] Open
Abstract
Investigating factors that promote group living in animals can help us to understand the evolution of sociality. The dark woolly bat, Kerivoula furva, forms small groups and uses furled leaves of banana (Musa formosana) as day roosts in subtropical Taiwan. In this study, we reported on the roosting ecology and social organization of K. furva. We examined whether ecological constraints, demographic traits, and physiological demands contributed to its sociality. From July 2014 to May 2016, we investigated the daily roost occupation rate, group size, and composition of each roost, and we calculated association indices in pairs. The results showed K. furva lived in groups throughout the year, and the average daily roost occupation rate was approximately 6.7% of all furled leaves that were suitable for roosting. The size of roosting groups of adults in each roost varied between 1 and 13; group size was independent of air temperature during both reproductive and nonreproductive seasons. The vast majority of roosting groups was composed of females and their young, and males frequently roosted solitarily or in a bachelor group. Forty adult bats were captured ≥4 times during the study period. The association indices in pairs of these 40 bats ranged between 0 and 0.83 with an average of 0.05 ± 0.14 (n = 780). The average association index of female-female pairs was significantly higher than that of female-male pairs and male-male pairs. Based on the association indices, the 40 bats were divided into seven social groups with social group sizes that varied between 2 and 10. Despite changing day roosts frequently, the relatively stable social bonds were maintained year-round. Our results that groups of K. furva were formed by active aggregation of multiple generation members supported the demographic traits hypothesis.
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Affiliation(s)
- Chia‐Wei Hsu
- Department of Forestry and Natural ResourcesNational Chiayi UniversityChiayi CityTaiwan
| | - Mei‐Ting Kao
- Department of Forestry and Natural ResourcesNational Chiayi UniversityChiayi CityTaiwan
| | - Cheng‐Han Chou
- Department of Forestry and Natural ResourcesNational Chiayi UniversityChiayi CityTaiwan
| | - Hsi‐Chi Cheng
- Endemic Species Research InstituteCouncil of AgricultureJiji TownshipTaiwan
| | - Jian‐Nan Liu
- Department of Forestry and Natural ResourcesNational Chiayi UniversityChiayi CityTaiwan
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16
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Bergeson SM, Brigham RM, O’Keefe JM. Free-ranging bats alter thermoregulatory behavior in response to reproductive stage, roost type, and weather. J Mammal 2021. [DOI: 10.1093/jmammal/gyab049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Abstract
Heterotherms vary their use of torpor and choice of refugia to deal with energetic stresses such as reproductive activity and extreme weather. We hypothesized that a temperate-region bat would vary its use of heterothermy in response to air temperature but use of torpor would also be influenced by reproductive stage and roost choice. To test this hypothesis, we collected data on skin temperatures of female Indiana bats (Myotis sodalis) carrying temperature-sensitive radiotransmitters during the summers of 2013–2015. We also measured internal temperatures and external characteristics of roosts used by these bats. We analyzed the influence of daytime air temperature, roost canopy closure, roost type, and bat reproductive stage, on daily heterothermy index and torpor characteristics of 17 bats during 103 full roost days (data collected consistently from when a bat entered its roost in the morning to when it emerged at night). Our data showed that Indiana bat heterothermy was influenced by reproductive stage, roost choice, and weather. Although they used torpor, pregnant bats were the least heterothermic (daily heterothermy index = 3.3 ± 0.6°C SE), followed by juvenile bats (5.6 ± 0.5°C), lactating bats (5.7 ± 0.5°C), and one postlactating bat (13.2 ± 1.6°C). Air temperature also influenced heterothermy of pregnant bats less than bats of other reproductive stages. Thermoregulatory strategies varied on a continuum from use of normothermia in warm roosts to use of long and deep bouts of torpor in cool roosts. The thermoregulatory strategy used seemed to be determined by potential reproductive costs of torpor and energetic consequences of weather. Because Indiana bats used different degrees of heterothermy throughout the summer maternity season, managers should offer maternity colonies an array of refugia to facilitate varying behaviors in response to weather and energetic demands.
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Affiliation(s)
- Scott M Bergeson
- Department of Biology, Purdue University Fort Wayne, Fort Wayne, IN 46805, USA
- Center for Bat Research, Outreach, and Conservation, Indiana State University, Terre Haute, IN 47809, USA
| | - R Mark Brigham
- Department of Biology, University of Regina, Regina, SK S4S 0A2,Canada
| | - Joy M O’Keefe
- Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61801, USA
- Center for Bat Research, Outreach, and Conservation, Indiana State University, Terre Haute, IN 47809, USA
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17
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Craig MC, Silva LO, Swoap SJ. Behavioral thermoregulation in the fasted C57BL/6 mouse. J Therm Biol 2021; 96:102821. [PMID: 33627261 DOI: 10.1016/j.jtherbio.2020.102821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/20/2020] [Accepted: 12/18/2020] [Indexed: 11/15/2022]
Abstract
Under relatively cool ambient temperatures and a caloric deficit, mice will undergo daily torpor - a short-term regulated reduction in metabolic rate with a concomitant drop in body temperature. Mice can alternatively achieve metabolic savings by utilizing behavioral changes, such as seeking a warmer environment. However, there is a lack of knowledge about the behavioral interaction between torpor utilization and thermotaxis. That is, if a fasted mouse is faced with a choice between a warm environment not conducive for torpor, and a cool environment that will induce torpor, which scenario will the fasting mouse choose? Here, the temperature preferences of fasted mice were studied using a temperature gradient device that allows a mouse to freely move along a gradient of temperatures. C57BL/6 mice were implanted with temperature telemeters that recorded location, core temperature (Tb), and activity concurrently over a 23-h period in the thermal gradient. When the gradient was on, mice preferred the warm end of the gradient when fed (71 ± 4% of the time) and even more so when fasted (84 ± 2%). When the gradient was on, the fasted minimum Tb was significantly higher (34.4 ± 0.3 °C) than when the gradient was off (27.7 ± 1.6 °C). Further, fasted mice lost significantly more weight when the gradient was off despite maintenance of a metabolically favorable lower minimum Tb in this condition. These results indicate that fasted mice not only prefer warm ambient temperatures when given the choice, but that it is also the pathway with more favorable metabolic outcomes in a period of reduced caloric intake.
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18
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Mavrodiev P, Fleischmann D, Kerth G, Schweitzer F. Quantifying individual influence in leading-following behavior of Bechstein's bats. Sci Rep 2021; 11:2691. [PMID: 33514763 PMCID: PMC7846810 DOI: 10.1038/s41598-020-80946-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 12/24/2020] [Indexed: 11/16/2022] Open
Abstract
Leading-following behavior as a way of transferring information about the location of resources is wide-spread in many animal societies. It represents active information transfer that allows a given social species to reach collective decisions in the presence of limited information. Although leading-following behavior has received much scientific interest in the form of field studies, there is a need for systematic methods to quantify and study the individual contributions in this information transfer, which would eventually lead us to hypotheses about the individual mechanisms underlying this behaviour. In this paper we propose a general methodology that allows us to (a) infer individual leading-following behaviour from discrete observational data and (b) quantify individual influence based on methods from social network analysis. To demonstrate our methodology, we analyze longitudinal data of the roosting behavior of two different colonies of Bechstein's bats in different years. Regarding (a) we show how the inference of leading-following events can be calibrated from data making it a general approach when only discrete observations are available. This allows us to address (b) by constructing social networks in which nodes represent individual bats and directed and weighted links-the leading-following events. We then show how social network theory can be used to define and quantify individual influence in a way that reflects the dynamics of the specific social network. We find that individuals can be consistently ranked regarding their influence in the information transfer. Moreover, we identify a small set of individuals that play a central role in leading other bats to roosts. In the case of Bechstein's bats this finding can direct future studies on the individual-level mechanisms that result in such collective pattern. More generally, we posit that our data-driven methodology can be used to quantify leading-following behavior and individual impact in other animal systems, solely based on discrete observational data.
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Affiliation(s)
- Pavlin Mavrodiev
- Chair of Systems Design, ETH Zurich, Weinbergstrasse 56/58, 8092, Zurich, Switzerland
| | - Daniela Fleischmann
- Applied Zoology and Nature Conservation, University of Greifswald, Loitzer Strasse 26, 17489, Greifswald, Germany
| | - Gerald Kerth
- Applied Zoology and Nature Conservation, University of Greifswald, Loitzer Strasse 26, 17489, Greifswald, Germany
| | - Frank Schweitzer
- Chair of Systems Design, ETH Zurich, Weinbergstrasse 56/58, 8092, Zurich, Switzerland.
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19
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Garbino GST, Feijó A, Beltrão-Mendes R, Da Rocha PA. Evolution of litter size in bats and its influence on longevity and roosting ecology. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blaa203] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Litter size varies in mammals, with about half of the species producing at least two offspring per gestation (polytocy). In bats, however, the modal litter size is one (monotocy), and polytocy is restricted to family Vespertilionidae. Here, we reconstruct the evolutionary history of polytocy in chiropterans and use phylogenetically informed regressions to investigate its relationship to roost type, longevity and group size. Our phylogenetic reconstructions suggested that production of multiple offspring was the ancestral condition in family Vespertilionidae. The distribution of monotocy/polytocy in Chiroptera was best explained by a minimum of two evolutionary transitions from monotocy to polytocy and by ≥ 18 transitions from polytocy to monotocy. The regression models showed that longevity and roost type explained the variation in litter size, whereas group size did not. Our analyses also revealed a greater diversity of polytocous bats in the Northern Hemisphere, in both temperate and tropical regions. We suggest that the high resource allocation to reproduction in polytocous bats limited their lifespan. The absence of a relationship between polytocy and group size indicates that the benefits of cooperative breeding surpass the costs of intrasexual competition in bats.
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Affiliation(s)
- Guilherme Siniciato Terra Garbino
- Laboratório de Mamíferos, Departamento de Ciências Biológicas, Escola Superior de Agricultura ‘Luiz de Queiroz’, Universidade de São Paulo, Piracicaba, São Paulo, Brazil
| | - Anderson Feijó
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beichen West Road, Beijing, China
| | - Raone Beltrão-Mendes
- Programa de Pós-Graduação em Ecologia e Conservação, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil
- Laboratório de Biologia da Conservação, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil
| | - Patrício Adriano Da Rocha
- Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil
- Laboratório de Mamíferos, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil
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20
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Monarchino MN, Johnson JS. Roost elevation and ambient temperature best predict use of summer heterothermy in eastern red bats. J Zool (1987) 2020. [DOI: 10.1111/jzo.12848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - J. S. Johnson
- Department of Biological Sciences Ohio University Athens OH USA
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21
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Katsis LKD, Linton DM, Macdonald DW. The effect of group size, reproductive condition and time period on sexual segregation patterns in three vespertilionid bat species. J Zool (1987) 2020. [DOI: 10.1111/jzo.12843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- L. K. D. Katsis
- Wildlife Conservation Research Unit (WildCRU) Department of Zoology The Recanati‐Kaplan Centre University of Oxford Tubney UK
| | - D. M. Linton
- Wildlife Conservation Research Unit (WildCRU) Department of Zoology The Recanati‐Kaplan Centre University of Oxford Tubney UK
| | - D. W. Macdonald
- Wildlife Conservation Research Unit (WildCRU) Department of Zoology The Recanati‐Kaplan Centre University of Oxford Tubney UK
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22
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Hałat Z, Dechmann DKN, Zegarek M, Ruczyński I. Male bats respond to adverse conditions with larger colonies and increased torpor use during sperm production. Mamm Biol 2020. [DOI: 10.1007/s42991-020-00071-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AbstractChanges in environmental conditions can have strong energetic effects on animals through limited food availability or increased thermoregulatory costs. Especially difficult are periods of increased energy expenditures, such as reproduction. Reproductive female bats from the temperate zone often aggregate in maternity colonies to profit from social thermoregulation to reduce torpor use and buffer the effects of poor conditions. The much rarer male colonies may form for similar reasons during testes development. Male colonies thus allow us to study the influence of environmental conditions on energy budget and colony size, without the confounding effects of parental care. We remotely monitored skin temperature and assessed colony size of male parti-coloured bats Vespertilio murinus during summer, and correlated those variables with environmental conditions and food availability (i.e. insect abundance). As we had hypothesized, we found that colony size increased at colder temperatures, but decreased at low wind speeds. Also as predicted, torpor use was relatively low, however, it did increase slightly during adverse conditions. Male sociality may be an adaptation to adverse environmental conditions during sexual maturation, but the pressure to avoid torpor during spermatogenesis may be lower than in pregnant or lactating females.
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23
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Nowack J, Dill V, Dausmann KH. Open-flow respirometry under field conditions: How does the airflow through the nest influence our results? J Therm Biol 2020; 92:102667. [PMID: 32888570 DOI: 10.1016/j.jtherbio.2020.102667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/01/2020] [Accepted: 07/06/2020] [Indexed: 11/26/2022]
Abstract
Open-flow respirometry is a common method to measure oxygen-uptake as a proxy of energy expenditure of organisms in real-time. Although most often used in the laboratory it has seen increasing application under field conditions. Air is drawn or pushed through a metabolic chamber or the nest with the animal, and the O2 depletion and/or CO2 accumulation in the air is analysed to calculate metabolic rate and energy expenditure. Under field conditions, animals are often measured within the microclimate of their nest and in contrast to laboratory work, the temperature of the air entering the nest cannot be controlled. Thus, the aim of our study was to determine the explanatory power of respirometry in a set-up mimicking field conditions. We measured O2 consumption of 14 laboratory mice (Mus musculus) using three different flow rates [50 L*h-1 (834 mL*min-1), 60 L*h-1 (1000 mL*min-1) and 70 L*h-1 (1167 mL*min-1)] and two different temperatures of the inflowing air; either the same as the temperature inside the metabolic chamber (no temperature differential; 20 °C), or cooler (temperature differential of 10 °C). Our results show that the energy expenditure of the mice did not change significantly in relation to a cooler airflow, nor was it affected by different flow rates, despite a slight, but significant decrease of about 1.5 °C in chamber temperature with the cooler airflow. Our study emphasises the validity of the results obtained by open-flow respirometry when investigating energy budgets and physiological responses of animals to ambient conditions. Nevertheless, subtle changes in chamber temperature in response to changes in the temperature and flow rate of the air pulled or pushed through the system were detectable. Thus, constant airflow during open-flow respirometry and consequent changes in nest/chamber temperature should be measured.
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Affiliation(s)
- Julia Nowack
- Institute of Zoology, Animal Ecology and Conservation, University Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany; School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, L3 3AF, Liverpool, UK.
| | - Veronika Dill
- Institute of Zoology, Animal Ecology and Conservation, University Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany; Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Kathrin H Dausmann
- Institute of Zoology, Animal Ecology and Conservation, University Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
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24
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Ruczyński I, Bartoń KA. Seasonal changes and the influence of tree species and ambient temperature on the fission-fusion dynamics of tree-roosting bats. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02840-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Abstract
Many species of bats live in dynamic associations in which individuals aggregate or split into smaller or larger groups, moving between roost sites, but factors influencing group size and roost switching decisions in bats living in fission-fusion societies are poorly understood. To test the extent to which fission-fusion dynamics are species-specific and shaped by environmental factors, we radio-tracked two closely related species: noctule bats Nyctalus noctula and Leisler’s bats N. leisleri in well-preserved, old-growth stands of the Białowieża Forest, where roost availability and diversity is high and bats can potentially freely exhibit fission-fusion behaviour. We estimated the number of bats per roost and noted the tree species selected as roost sites. We evaluated the influence of ambient temperature and roost tree species on bat group size and the process of roost switching, and their seasonal component. Our results revealed that bat group size showed species-specific differences in seasonal variation, relationship to ambient temperature and tree species. The number of noctule bats emerging from a roost was relatively stable with a weak tendency to decrease during the breeding season while the number of Leisler’s bats emerging from a roost increased when the juveniles started to be volant. Group size of noctule bats increased with ambient temperature. Leisler’s bats formed smaller colonies in oaks and ashes than in other tree species. Roost switching rate was associated with ambient temperature and tree species selected by the bats. The bats changed roosts more frequently when the minimum ambient temperature increased, and less often in ashes than in oaks and other tree species. Our results show that bat group size and roost switching behaviour are shaped by both environmental factors and the stage of reproduction.
Significance statement
Environmental factors may affect group size and roost switching behaviour of bats forming fission-fusion associations, but this is expected to vary depending on body size, environmental conditions, as well as seasonally. Few studies have explored this behaviour in tree-dwelling bats and examined how it differs between species. Here, we studied the group size dynamics and the process of roost switching in closely related bat species living in well-preserved, European old-growth forests, for which the knowledge of these patterns is particularly poor. We demonstrate for the first time that bat group size and roost switching rate relates to roost tree species selected by bats, the ambient temperature and varies seasonally, and that these effects are species-specific. The results point out the importance of the availability of suitable roost trees providing a range of microclimatic conditions for maintaining efficient fission-fusion dynamics throughout the reproductive period.
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25
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Hernández-Montero JR, Reusch C, Simon R, Schöner CR, Kerth G. Free-ranging bats combine three different cognitive processes for roost localization. Oecologia 2020; 192:979-988. [PMID: 32236689 PMCID: PMC7165157 DOI: 10.1007/s00442-020-04634-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/12/2020] [Indexed: 01/02/2023]
Abstract
Animals have evolved different cognitive processes to localize crucial resources that are difficult to find. Relevant cognitive processes such as associative learning and spatial memory have commonly been studied in a foraging related context under controlled laboratory conditions. However, in natural environments, animals can use multiple cognitive processes to localize resources. In this field study, we used a pairwise choice experiment and automatic roost monitoring to assess how individually marked, free-ranging Bechstein’s bats belonging to two different colonies use associative learning, spatial memory and social information when localizing suitable day roosts. To our knowledge, this study tests for the first time how associative learning, spatial memory and social information are used in the process of roost localization in bats under the natural conditions. We show that, when searching for new roosts, bats used associative learning to discriminate between suitable and unsuitable roosts. For re-localizing previously occupied roosts, bats used spatial memory rather than associative learning. Moreover, bats significantly improved the localization of suitable unfamiliar roosts and tended to increase their accuracy to re-localize previously occupied day roosts using social information. Our field experiments suggest that Bechstein’s bats make hierarchical use of different cognitive processes when localizing day roosts. More generally, our study underlines that evaluating different cues under natural conditions is fundamental to understanding how natural selection has shaped the cognitive processes used for localizing resources.
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Affiliation(s)
- Jesús R Hernández-Montero
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Loitzerstraße 26, 17489, Greifswald, Germany.
| | - Christine Reusch
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Loitzerstraße 26, 17489, Greifswald, Germany
| | - Ralph Simon
- Department of Ecological Science/Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Caroline Regina Schöner
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Loitzerstraße 26, 17489, Greifswald, Germany
| | - Gerald Kerth
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Loitzerstraße 26, 17489, Greifswald, Germany
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26
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Abstract
Cimicid insects, bed bugs and their allies, include about 100 species of blood-feeding ectoparasites. Among them, a few have become widespread and abundant pests of humans. Cimicids vary in their degree of specialization to hosts. Whereas most species specialize on insectivorous birds or bats, the common bed bug can feed on a range of distantly related host species, such as bats, humans, and chickens. We suggest that association with humans and generalism in bed bugs led to fundamentally different living conditions that fostered rapid growth and expansion of their populations. We propose that the evolutionary and ecological success of common bed bugs reflected exploitation of large homeothermic hosts (humans) that sheltered in buildings. This was a departure from congeners whose hosts are much smaller and often heterothermic. We argue that interesting insights into the biology of pest species may be obtained using an integrated view of their ecology and evolution.
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Affiliation(s)
- Benoit Talbot
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON K1G 5Z3, Canada
| | - Nusha Keyghobadi
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Brock Fenton
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
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27
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Presence of humans and domestic cats affects bat behaviour in an urban nursery of greater horseshoe bats (Rhinolophus ferrumequinum). Behav Processes 2019; 164:4-9. [PMID: 30951813 DOI: 10.1016/j.beproc.2019.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 11/22/2022]
Abstract
Proximity to humans is a primary stressor for wildlife, especially in urban habitats where frequent disturbance may occur. Several bat species often roost in buildings but while the effects of disturbance inside the roost are well documented, little is known about those occurring in the proximity of roosts. We tested the effects of anthropogenic stressors on bats by monitoring reactions to disturbance in a colony of greater horseshoe bats (Rhinolophus ferrumequinum). We assessed disturbance by recording and quantifying the presence of people, domestic cats and noise sources near the roost. Disturbance outside the roost caused the disruption of roosting clusters; when cats entered the roost, bats decreased indoor flight activity. Emergence timing was delayed when people were close to the roost exit, and the delay increased along with the number of people. The occurrence of a cat increased the degree of group clustering during emergence. Cats entered the roost especially when young bats were present, and bat remains occurred in 30% of the cat scats we examined. We show that the occurence of human activities near roosts and free-ranging domestic cats are important albeit overlooked sources of disturbance.
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28
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29
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Graham JL, Bauer CM, Heidinger BJ, Ketterson ED, Greives TJ. Early-breeding females experience greater telomere loss. Mol Ecol 2019; 28:114-126. [PMID: 30565787 DOI: 10.1111/mec.14952] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 10/12/2018] [Accepted: 10/22/2018] [Indexed: 08/02/2024]
Abstract
Annual reproductive success is often highest in individuals that initiate breeding early, yet relatively few individuals start breeding during this apparently optimal time. This suggests that individuals, particularly females who ultimately dictate when offspring are born, incur costs by initiating reproduction early in the season. We hypothesized that increases in the ageing rate of somatic cells may be one such cost. Telomeres, the repetitive DNA sequences on the ends of chromosomes, may be good proxies of biological wear and tear as they shorten with age and in response to stress. Using historical data from a long-term study population of dark-eyed juncos (Junco hyemalis), we found that telomere loss between years was greater in earlier breeding females, regardless of chronological age. There was no relationship between telomere loss and the annual number of eggs laid or chicks that reached independence. However, telomere loss was greater when temperatures were cooler, and cooler temperatures generally occur early in the season. This suggests that environmental conditions could be the primary cause of accelerated telomere loss in early breeders.
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Affiliation(s)
- Jessica L Graham
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota
| | - Carolyn M Bauer
- Department of Biology, Adelphi University, Garden City, New York
| | - Britt J Heidinger
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota
| | | | - Timothy J Greives
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota
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Turbill C, Körtner G, Geiser F. Roost use and thermoregulation by female Australian long-eared bats (Nyctophilus geoffroyi and N. gouldi) during pregnancy and lactation. AUST J ZOOL 2019. [DOI: 10.1071/zo20036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Small insectivorous bats commonly use torpor while day-roosting, even in summer. However, reproductive female bats are believed to benefit from avoiding torpor because a constant, elevated body temperature maximises the rate of offspring growth, which could increase offspring survival. We used temperature-sensitive radio-transmitters to locate roosts and document the thermal biology of pregnant and lactating females of Nyctophilus geoffroyi (9 g) and N. gouldi (11 g) at a woodland in a cool temperate climate. Unlike males, reproductive female Nyctophilus spp. roosted as small groups (<25) within insulated tree cavities. Roost switching occurred every 3.7 ± 1.5 (N. geoffroyi) or 1.7 ± 0.8 days (N. gouldi), and radio-tagged individuals roosted together and apart on different days. Skin temperature during roosting was most often between 32 and 36°C, and torpor was used infrequently. Male Nyctophilus have been shown in previous studies to use torpor daily during summer. These contrasting torpor patterns likely reflect the warmed cavities occupied by maternity colonies and the thermally unstable shallow crevices occupied by individual males. Our results support the hypothesis that availability of thermally suitable roosts will influence thermoregulatory patterns of reproductive females and hence the growth rates and survival of their offspring. Thus, it is important to conserve woodland habitat with trees in a range of decay stages to provide opportunities for selection and movement among roost trees by reproductive female bats.
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Amorim F, Jorge I, Beja P, Rebelo H. Following the water? Landscape-scale temporal changes in bat spatial distribution in relation to Mediterranean summer drought. Ecol Evol 2018; 8:5801-5814. [PMID: 29938094 PMCID: PMC6010748 DOI: 10.1002/ece3.4119] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 03/14/2018] [Accepted: 03/29/2018] [Indexed: 11/16/2022] Open
Abstract
Understanding how the spatial distribution of ecological resources shapes species' diversity and abundance in human-modified landscapes is a central theme in conservation biology. However, studies often disregard that such patterns may vary over time, thereby potentially missing critical environmental constraints to species persistence. This may be particularly important in highly mobile species such as bats, which are able to track temporal variations in spatial resource distribution. Here we test the hypothesis that bats in Mediterranean landscapes are strongly affected by the progressive reduction in water availability during the seasonal summer drought. We analyzed the effects of landscape composition and structure on bat diversity and activity, during pregnancy, lactation, and postlactation periods, and identified the most influential variables within and across periods. Water bodies showed the strongest positive effect on bats, followed by riparian habitats and areas with steeper (>30%) slopes. However, while during pregnancy, there were only small landscape effects, these increased during lactation and postlactation, highlighting a progressively stronger association with water habitats during the summer drought. The spatial projection of habitat models showed that the landscape distribution of bat diversity and activity hotspots changed markedly over time. During pregnancy, the spatial pattern of hotspot distribution was weakly defined, while during lactation and particularly postlactation, there was a concentration of hotspots along permanently flowing watercourses. Our study highlights that permanently flowing watercourses are critical for bat conservation in Mediterranean landscapes, calling for measures to counteract their ongoing degradation due in particular to climate change, water abstraction and damming. More generally, our study underlines the importance of considering the temporal dimension in habitat selection studies, without which there is the risk of overlooking the importance of habitats that are key for species persistence only at certain times of the year.
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Affiliation(s)
- Francisco Amorim
- CIBIO‐InBIO, Research Center in Biodiversity and Genetic ResourcesUniversity of PortoPortoPortugal
- CEABN‐InBIOCentre for Applied Ecology “Prof. Baeta Neves”Institute of AgronomyUniversity of LisbonLisbonPortugal
- Faculty of SciencesUniversity of PortoPortoPortugal
| | - Inês Jorge
- Faculty of SciencesUniversity of PortoPortoPortugal
| | - Pedro Beja
- CIBIO‐InBIO, Research Center in Biodiversity and Genetic ResourcesUniversity of PortoPortoPortugal
- CEABN‐InBIOCentre for Applied Ecology “Prof. Baeta Neves”Institute of AgronomyUniversity of LisbonLisbonPortugal
| | - Hugo Rebelo
- CIBIO‐InBIO, Research Center in Biodiversity and Genetic ResourcesUniversity of PortoPortoPortugal
- CEABN‐InBIOCentre for Applied Ecology “Prof. Baeta Neves”Institute of AgronomyUniversity of LisbonLisbonPortugal
- School of Biological SciencesUniversity of BristolBristolUK
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Linton DM, Macdonald DW. Spring weather conditions influence breeding phenology and reproductive success in sympatric bat populations. J Anim Ecol 2018; 87:1080-1090. [PMID: 29635800 DOI: 10.1111/1365-2656.12832] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/26/2018] [Indexed: 12/01/2022]
Abstract
Climate is known to influence breeding phenology and reproductive success in temperate-zone bats, but long-term population level studies and interspecific comparisons are rare. Investigating the extent to which intrinsic (i.e. age), and extrinsic (i.e. spring weather conditions), factors influence such key demographic parameters as the proportion of females becoming pregnant, or completing lactation, each breeding season, is vital to understanding of bat population ecology and life-history traits. Using data from 12 breeding seasons (2006-2017), encompassing the reproductive histories of 623 Myotis daubentonii and 436 Myotis nattereri adult females, we compare rates of recruitment to the breeding population and show that these species differ in their relative sensitivity to environmental conditions and climatic variation, affecting annual reproductive success at the population level. We demonstrate that (1) spring weather conditions influence breeding phenology, with warm, dry and calm conditions leading to earlier parturition dates and advanced juvenile development, whilst cold, wet and windy weather delays birth timing and juvenile growth; (2) reproductive rates in first-year females are influenced by spring weather conditions in that breeding season and in the preceding breeding season when each cohort was born. Pregnancy and lactation rates were both higher when favourable spring foraging conditions were more prevalent; (3) reproductive success increases with age in both species, but at different rates; (4) reproductive rates were consistently higher, and showed less interannual variation, in second-year and older M. daubentonii (mean 91.55% ± 0.05 SD) than M. nattereri (mean 72.74% ± 0.15 SD); (5) estimates of reproductive success at the population level were highly correlated with the size of the juvenile cohort recorded each breeding season. Improving understanding of the influence of environmental conditions, especially extreme climatic fluctuations, and the identification of critical periods (i.e. spring for reproductive female bats in temperate zones), which have disproportionate and lasting impacts on breeding phenology and reproductive success at a population level, is critical for improving predictions of the likely impact of climate change on bat populations.
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Affiliation(s)
- Danielle M Linton
- Department of Zoology, Wildlife Conservation Research Unit (WildCRU), The Recanati-Kaplan Centre, University of Oxford, Tubney, UK
| | - David W Macdonald
- Department of Zoology, Wildlife Conservation Research Unit (WildCRU), The Recanati-Kaplan Centre, University of Oxford, Tubney, UK
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Webber QMR, Willis CKR. An experimental test of effects of ambient temperature and roost quality on aggregation by little brown bats (Myotis lucifugus). J Therm Biol 2018; 74:174-180. [PMID: 29801624 DOI: 10.1016/j.jtherbio.2018.03.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 02/26/2018] [Accepted: 03/22/2018] [Indexed: 01/08/2023]
Abstract
Environmental factors, such as ambient temperature (Ta) or roost/nest quality, can influence social behaviour of small-bodied endotherms because individuals may aggregate for social thermoregulation when Ta is low or select the warmest possible sites for roosting. Female temperate bats form maternity colonies in spring to communally raise pups and exploit social thermoregulation. They also select roosts with warm microclimates because low roost temperature (Troost) delays juvenile development. We studied captive female little brown bats (Myotis lucifugus) to test the hypothesis that variation in Ta and Troost influence social group size. First, we predicted that female bats would preferentially select artificially heated roosts over unheated roosts. Second, we predicted that, as Ta decreased, group size would increase because bats would rely more heavily on social thermoregulation. Third, we predicted that experimentally increasing Troost (i.e., roost quality) above Ta would result in larger group sizes due to greater aggregation in high quality roosts. We captured 34 females from a maternity colony and housed them in a flight-tent provisioned with four bat boxes. Each box was outfitted with a heating pad and thermostat. Over the course of eight-days we heated each roost box in sequence to near thermoneutral Troost for two days. Bats preferentially selected heated roosts over unheated roosts but, contrary to our prediction, group size decreased when Troost was much greater than Ta (i.e., when the benefits of a warm roost should have been highest). Our results suggest that social thermoregulation and the availability of warm roosts influence aggregation in bats and have implications for the potential of summer habitat protection and enhancement to help bat populations in the face of threats like white-nose syndrome.
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Affiliation(s)
- Quinn M R Webber
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR), University of Winnipeg, MB, Canada.
| | - Craig K R Willis
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR), University of Winnipeg, MB, Canada.
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34
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Seasonal energetics and torpor use in North American flying squirrels. J Therm Biol 2017; 70:46-53. [DOI: 10.1016/j.jtherbio.2017.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 10/04/2017] [Accepted: 10/21/2017] [Indexed: 11/18/2022]
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35
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Russo D, Cistrone L, Budinski I, Console G, Della Corte M, Milighetti C, Di Salvo I, Nardone V, Brigham RM, Ancillotto L. Sociality influences thermoregulation and roost switching in a forest bat using ephemeral roosts. Ecol Evol 2017; 7:5310-5321. [PMID: 28770069 PMCID: PMC5528228 DOI: 10.1002/ece3.3111] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/01/2017] [Accepted: 05/05/2017] [Indexed: 02/05/2023] Open
Abstract
In summer, many temperate bat species use daytime torpor, but breeding females do so less to avoid interferences with reproduction. In forest-roosting bats, deep tree cavities buffer roost microclimate from abrupt temperature oscillations and facilitate thermoregulation. Forest bats also switch roosts frequently, so thermally suitable cavities may be limiting. We tested how barbastelle bats (Barbastella barbastellus), often roosting beneath flaking bark in snags, may thermoregulate successfully despite the unstable microclimate of their preferred cavities. We assessed thermoregulation patterns of bats roosting in trees in a beech forest of central Italy. Although all bats used torpor, females were more often normothermic. Cavities were poorly insulated, but social thermoregulation probably overcomes this problem. A model incorporating the presence of roost mates and group size explained thermoregulation patterns better than others based, respectively, on the location and structural characteristics of tree roosts and cavities, weather, or sex, reproductive or body condition. Homeothermy was recorded for all subjects, including nonreproductive females: This probably ensures availability of a warm roosting environment for nonvolant juveniles. Homeothermy may also represent a lifesaver for bats roosting beneath loose bark, very exposed to predators, because homeothermic bats may react quickly in case of emergency. We also found that barbastelle bats maintain group cohesion when switching roosts: This may accelerate roost occupation at the end of a night, quickly securing a stable microclimate in the newly occupied cavity. Overall, both thermoregulation and roost-switching patterns were satisfactorily explained as adaptations to a structurally and thermally labile roosting environment.
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Affiliation(s)
- Danilo Russo
- Wildlife Research UnitDipartimento di AgrariaUniversità degli Studi di Napoli Federico IIPorticiItaly
- School of Biological SciencesUniversity of BristolBristolUK
| | | | - Ivana Budinski
- Department of Genetic ResearchInstitute for Biological Research “Siniša Stanković”University of BelgradeBelgradeSerbia
| | - Giulia Console
- Dipartimento di BiologiaUniversità degli Studi di FirenzeFirenzeItaly
| | - Martina Della Corte
- Dipartimento di Biologia Strutturale e FunzionaleUniversità degli Studi di Napoli Federico IINapoliItaly
| | - Claudia Milighetti
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”Università degli Studi di Roma “La Sapienza”RomaItaly
| | - Ivy Di Salvo
- Wildlife Research UnitDipartimento di AgrariaUniversità degli Studi di Napoli Federico IIPorticiItaly
| | - Valentina Nardone
- Wildlife Research UnitDipartimento di AgrariaUniversità degli Studi di Napoli Federico IIPorticiItaly
| | | | - Leonardo Ancillotto
- Wildlife Research UnitDipartimento di AgrariaUniversità degli Studi di Napoli Federico IIPorticiItaly
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Torquetti CG, Silva MX, Talamoni S. Differences between caves with and without bats in a Brazilian karst habitat. ZOOLOGIA (CURITIBA) 2017. [DOI: 10.3897/zoologia.34.e13732] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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37
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Zeus VM, Puechmaille SJ, Kerth G. Conspecific and heterospecific social groups affect each other's resource use: a study on roost sharing among bat colonies. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2016.11.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Patriquin KJ, Leonard ML, Broders HG, Ford WM, Britzke ER, Silvis A. Weather as a proximate explanation for fission–fusion dynamics in female northern long-eared bats. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.09.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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39
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Kuepper ND, Melber M, Kerth G. Nightly clustering in communal roosts and the regular presence of adult females at night provide thermal benefits for juvenile Bechstein's bats. Mamm Biol 2016. [DOI: 10.1016/j.mambio.2015.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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40
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Nowack J, Geiser F. Friends with benefits: the role of huddling in mixed groups of torpid and normothermic animals. ACTA ACUST UNITED AC 2015; 219:590-6. [PMID: 26685170 DOI: 10.1242/jeb.128926] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 12/01/2015] [Indexed: 12/24/2022]
Abstract
Huddling and torpor are widely used for minimizing heat loss by mammals. Despite the questionable energetic benefits from social heterothermy of mixed groups of warm normothermic and cold torpid individuals, the heterothermic Australian sugar glider (Petaurus breviceps) rests in such groups during the cold season. To unravel why they might do so, we examined torpor expression of two sugar glider groups of four individuals each in outside enclosures during winter. We observed 79 torpor bouts during 50 days of observation and found that torpor bouts were longer and deeper when all individuals of a group entered torpor together, and therefore infer that they would have saved more energy in comparison to short and shallow solitary torpor bouts. However, all gliders of either group only expressed torpor uniformly in response to food restriction, whereas on most occasions at least one individual per group remained normothermic. Nevertheless, the presence of warm gliders in mixed groups also appears to be of energetic advantage for torpid individuals, because nest box temperature was negatively correlated with the number of torpid gliders, and normothermic individuals kept the nest temperature at a value closer to the threshold for thermoregulatory heat production during torpor. Our study suggests that mixed groups of torpid and normothermic individuals are observed when environmental conditions are adverse but food is available, leading to intermediate energy savings from torpor. However, under especially challenging conditions and when animals are starving, energy savings are maximized by uniform and pronounced expression of torpor.
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Affiliation(s)
- Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
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41
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Pretzlaff I, Rau D, H. Dausmann K. Energy expenditure increases during the active season in the small, free-living hibernator Muscardinus avellanarius. Mamm Biol 2014. [DOI: 10.1016/j.mambio.2013.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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42
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Thogmartin WE, McKann PC. Large-scale climate variation modifies the winter grouping behavior of endangered Indiana bats. J Mammal 2014. [DOI: 10.1644/13-mamm-a-098] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Affiliation(s)
- C. Stawski
- Institute of Environmental Sciences; Jagiellonian University; Kraków Poland
- Centre for Behavioural and Physiological Ecology, Zoology; University of New England; Armidale NSW Australia
| | - C. K. R. Willis
- Department of Biology and Centre for Forest Interdisciplinary Research; University of Winnipeg; Winnipeg Canada
| | - F. Geiser
- Centre for Behavioural and Physiological Ecology, Zoology; University of New England; Armidale NSW Australia
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Kilgour R, Faure P, Brigham R. Evidence of social preferences in big brown bats (Eptesicus fuscus). CAN J ZOOL 2013. [DOI: 10.1139/cjz-2013-0057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Among social species, iterative interactions may lead to social preferences among group-mates and often are associated with increased mating opportunities or improved indirect fitness benefits. Although preferential associations have been documented in multiple species, this phenomenon has never been empirically studied in bats—the second largest order of mammals, where many of the 1200+ species live in groups of tens to hundreds of individuals. Given the current understanding of the social behaviour exhibited in this species, we explored the possibility that adult female big brown bats (Eptesicus fuscus (Beauvois, 1796)) show preferential association between group-mates using a pairwise choice design with individuals from a captive colony. Focal individuals were placed in a Y-maze and were given free choice of two familiar conspecifics. We measured the time focal individuals spent in close proximity to each conspecific. Our results indicate that some bats exhibit preferential association between group-mates, as multiple individuals spent significantly more time in close proximity to one conspecific versus another, despite randomizing the position of stimulus bats between trials. Given the frequent and long-term associations between group members of this species, social preferences could play a significant role in the outcomes of their long-term fitness.
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Affiliation(s)
- R.J. Kilgour
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - P.A. Faure
- Department of Psychology, Neuroscience, and Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - R.M. Brigham
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
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Dausmann KH, Wein J, Turner JM, Glos J. Absence of heterothermy in the European red squirrel (Sciurus vulgaris). Mamm Biol 2013. [DOI: 10.1016/j.mambio.2013.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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46
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Bechstein’s bats maintain individual social links despite a complete reorganisation of their colony structure. Naturwissenschaften 2013; 100:895-8. [PMID: 23949307 DOI: 10.1007/s00114-013-1090-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 07/31/2013] [Accepted: 08/03/2013] [Indexed: 10/26/2022]
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Female Bechstein's bats adjust their group decisions about communal roosts to the level of conflict of interests. Curr Biol 2013; 23:1658-62. [PMID: 23954425 DOI: 10.1016/j.cub.2013.06.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 05/31/2013] [Accepted: 06/21/2013] [Indexed: 11/22/2022]
Abstract
Most social animals depend on group decisions for coordination. Recent models suggest that the level of interindividual conflict strongly influences whether groups reach a consensus during decision making. However, few experimental studies have explored how wild animals make group decisions in situations with conflicting interests. Such experimental data are particularly lacking for animal societies with regular fission and fusion of subgroups. In this long-term study, we varied the level of conflict of interest among members of three wild Bechstein's bat (Myotis bechsteinii) colonies with high fission-fusion dynamics experimentally to explore whether the bats adapt their group decisions about communal roosts accordingly. In situations with low levels of conflict of interest, a minority of bats experiencing a roost as suitable was sufficient for a group consensus to use it communally. In contrast, if their interests diverged strongly, the bats no longer sought a compromise, but based their roosting decisions on individual preferences instead. Our results demonstrate that the rules applied to make group decisions can vary with the level of conflict among the individual interests of group members. Our findings are in agreement with predictions of the models and provide evidence for highly flexible group decisions within species.
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48
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Olson CR, Barclay RM. Concurrent changes in group size and roost use by reproductive female little brown bats (Myotis lucifugus). CAN J ZOOL 2013. [DOI: 10.1139/cjz-2012-0267] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Group formation is beneficial for many small endotherms, in part to create favourable conditions for developing offspring. However, for individuals occupying spatially limited structures, such as tree cavities, group formation may influence—and be influenced by—the range of structures available for use. This may be especially true of bats, which often form maternity groups that regularly change in size. We examined colonies of tree-roosting little brown bats (Myotis lucifugus (LeConte, 1831)) in northern Alberta to address two questions: (1) is group size associated with patterns of roost use, in particular the use of large-diameter trees, and (2) does group size change during reproduction and correspond to changes in roost use? We located roosts over 2 years using radiotelemetry and conducted exit counts at a subset of these roosts. Larger diameter trees had larger and more variable group sizes. Roost-tree diameter peaked near the start of parturition, the time when bats formed the largest groups. We suggest that large groups are especially beneficial at this time due to the thermoregulatory benefits to small, unfurred pups. Our results indicate that roost use and group size are interrelated and that large-diameter trees may be especially beneficial by supporting a wider range of group sizes.
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Affiliation(s)
- Cory R. Olson
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Robert M.R. Barclay
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
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49
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Kilgour RJ, Brigham RM. The Relationships between Behavioural Categories and Social Influences in the Gregarious Big Brown Bat (Eptesicus fuscus). Ethology 2013. [DOI: 10.1111/eth.12052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
| | - R. Mark Brigham
- Department of Biology; University of Regina; Regina; SK; Canada
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50
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Johnson JS, Lacki MJ. Summer heterothermy in Rafinesque's big-eared bats (Corynorhinus rafinesquii) roosting in tree cavities in bottomland hardwood forests. J Comp Physiol B 2012; 183:709-21. [PMID: 23269613 DOI: 10.1007/s00360-012-0728-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/13/2012] [Accepted: 11/18/2012] [Indexed: 11/26/2022]
Abstract
Many small mammals are heterothermic endotherms capable of maintaining an elevated core body temperature or reducing their thermoregulatory set point to enter a state of torpor. Torpor can confer substantial energy savings, but also incurs ecological costs, such as hindering allocation of energy towards reproduction. We placed temperature-sensitive radio transmitters on 44 adult Rafinesque's big-eared bats (Corynorhinus rafinesquii) and deployed microclimate dataloggers inside 34 day roosts to compare the use of torpor by different sex and reproductive classes of bats during the summer. We collected 324 bat-days of skin-temperature data from 36 females and 4 males. Reproductive females employed fewer torpor bouts per day than non-reproductive females and males (P < 0.0001), and pregnant and lactating females had higher average (P < 0.0001) and minimum (P < 0.0001) skin temperatures than non-reproductive females. Pregnant females spent less time torpid (P < 0.0001) than non-reproductive females, but lactating females used relatively deep, long torpor bouts. Microclimates varied inside tree species with different configurations of entrances to the roost cavity (P < 0.0001). Bats spent more time torpid when roosting in water tupelo (Nyssa aquatica) trees possessing only a basal entrance to the cavity (P = 0.001). Of the tree species used as roosts, water tupelo cavities exhibited the least variable daytime and nighttime temperatures. These data demonstrate that use of summer torpor is not uniform among sex and reproductive classes in Rafinesque's big-eared bat, and variation in microclimate among tree roosts due to species and structural characteristics facilitates the use of different thermoregulatory strategies in these bats.
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Affiliation(s)
- Joseph S Johnson
- Department of Forestry, University of Kentucky, Lexington, KY 40546, USA.
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