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López-Roig M, Piera E, Serra-Cobo J. Thinner bats to face hibernation as response to climate warming. Sci Rep 2024; 14:2117. [PMID: 38267504 PMCID: PMC10808443 DOI: 10.1038/s41598-024-52459-9] [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: 05/03/2023] [Accepted: 01/18/2024] [Indexed: 01/26/2024] Open
Abstract
One of the principal consequences of climate warming on hibernating mammals could be the loss of optimal conditions for hibernation. Although hibernating mammals, like bats, may be particularly vulnerable to climate warming due to a potential reduction of energy saving during the hibernation, there is a lack of knowledge regarding how they will be affected and how they will respond to this impact. Here, we examine the variation in the body condition of Schreiber's bent-winged bat (Miniopterus schreibersii) to investigate changes in the optimization energy demand. Using a 20-year dataset (1998-2017), we analyse the temporal trends of body condition in three key stages of the hibernation period: onset and end of hibernation and early activity. Our results indicate that body condition at the onset and end of hibernation have decreased significantly over these 20 years. However, despite this lower body condition, the decrease of mass loss rate in the last decade (although not significant) indicate a greater saving of fat reserves. The significant increase in winter temperatures did not affect body condition or reserve depletion, instead, lower body condition was observed with a higher number of days below 0 °C. Unlike other hibernating bat species, the females had lower fat reserves than males in all three periods considered. This study indicates that hibernation energy requirements could be changing as an adaptation to a warmer climate and that hibernating bats can survive the winter by optimizing their lower accumulation of reserves.
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Affiliation(s)
- Marc López-Roig
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
- Institut de Recerca de Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Eduard Piera
- Infraestructures.Cat (Generalitat de Catalunya), C/dels Vergós, 36-42, 08017, Barcelona, Spain
| | - Jordi Serra-Cobo
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Institut de Recerca de Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
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2
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Pikula J, Brichta J, Seidlova V, Piacek V, Zukal J. Higher antibody titres against Pseudogymnoascus destructans are associated with less white-nose syndrome skin lesions in Palearctic bats. Front Immunol 2023; 14:1269526. [PMID: 38143741 PMCID: PMC10739372 DOI: 10.3389/fimmu.2023.1269526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 11/28/2023] [Indexed: 12/26/2023] Open
Abstract
Introduction Serological tests can be used to test whether an animal has been exposed to an infectious agent, and whether its immune system has recognized and produced antibodies against it. Paired samples taken several weeks apart then document an ongoing infection and/or seroconversion. Methods In the absence of a commercial kit, we developed an indirect enzyme-linked immunosorbent assay (ELISA) to detect the fungus-specific antibodies for Pseudogymnoascus destructans, the agent of white-nose syndrome in bats. Results and Discussion Samples collected from European Myotis myotis (n=35) and Asian Myotis dasycneme (n=11) in their hibernacula at the end of the hibernation period displayed 100% seroprevalence of antibodies against P. destructans, demonstrating a high rate of exposure. Our results showed that the higher the titre of antibodies against P. destructans, the lower the infection intensity, suggesting that a degree of protection is provided by this arm of adaptive immunity in Palearctic bats. Moreover, P. destructans infection appears to be a seasonally self-limiting disease of Palearctic bats showing seroconversion as the WNS skin lesions heal in the early post-hibernation period.
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Affiliation(s)
- Jiri Pikula
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
- CEITEC: Central European Institute of Technology, University of Veterinary Sciences Brno, Brno, Czechia
| | - Jiri Brichta
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
| | - Veronika Seidlova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
| | - Vladimir Piacek
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
| | - Jan Zukal
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia
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3
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Fraser EE, McGuire LP. Prehibernation swarming in temperate bats: a critical transition between summer activity and hibernation. CAN J ZOOL 2023. [DOI: 10.1139/cjz-2022-0129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
In this contribution to Dr. Brock Fenton's Festschrift, we briefly reflect on Dr. Fenton's seminal works examining bat swarming behaviour in Ontario and use these reflections as a launch pad to conduct a global review on autumn swarming in bats, and underlying hypotheses to explain this behaviour. Our review frames the swarming period as a time of critical transitions, during which bats must balance multiple life history trade-offs, and we consider how various intrinsic and extrinsic factors may contribute to inter- and intraspecific differences in autumn behaviour. We discuss the transition away from summer residency, including maternity colony breakup, day roosting, and migration during autumn. We review key life history elements of swarming, including mating behaviours and associated reproductive condition, genetic exchange during swarming, and variation among sexes, ages, and species. Finally, we discuss the behaviours and physiological states of bats transitioning from the swarming period to hibernation. Throughout, we identify common patterns and also exceptions. Over 50 years of research has yielded many insights into autumn swarming, but knowledge gaps remain. Future research focus on a greater diversity of species will reveal general principles underlying the transition from summer active season, through the swarming period, and into winter hibernation.
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Affiliation(s)
- Erin E. Fraser
- School of Science and the Environment, Memorial University of Newfoundland (Grenfell Campus), 20 University Drive, Corner Brook, NL A2H 5G4, Canada
| | - Liam P. McGuire
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1, Canada
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4
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Takatsuki S, Hosoi E, Tado H. Food or rut: contrasting seasonal patterns in fat deposition between males and females of northern and southern sika deer populations in Japan. MAMMALIA 2023. [DOI: 10.1515/mammalia-2022-0092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Abstract
Overwintering is important for the survival of northern mammals, and northern ungulates deposit body fat. Researchers have interpreted fat deposition as an adaptation to food shortages during winter. However, it is likely that reproductive activities also affect fat deposition. We compared kidney fat indices (KFIs) of sika deer (Cervus nippon) between the northern and southern populations in Japan. In the northern population, the KFIs of adult males and females peaked during summer and autumn, respectively. In adult males, the KFIs abruptly declined during the rut (October), while in yearling males and fawns, they were low in summer. In the southern population, KFIs of adult males were high in summer but decreased in October. KFIs of adult females were low and increased in December–January. KFIs of fawns were low. These results suggest that most classes of the southern population did not deposit much fat during the summer except for adult males. The result that southern adult males displayed as much fat deposition as the northern males suggests that body fat was deposited not only for overwintering but also for reproductive activity of adult males.
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Affiliation(s)
- Seiki Takatsuki
- Life Museum of Azabu University , Fuchinobe 1-17-71, Chuo-ku , Sagamihara , 252-5201 , Kanagawa , Japan
| | - Eiji Hosoi
- Yamaguchi University , Yamaguchi , Japan
| | - Hiroyuki Tado
- The Yamaguchi Prefectural Agriculture & General Technology Center , Yamaguchi , Japan
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5
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Medina-Bello KI, Vázquez-Fuerte R, Ayala-Berdon J. The big brown bat ( Eptesicus fuscus) reduces its body mass during winter in a tropical montane ecosystem of central Mexico. MAMMALIA 2022. [DOI: 10.1515/mammalia-2022-0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
Most animals face changes in the availability of food and the environmental conditions in the places where they live. In response, they need to adjust their behavioral, physiological, and morphological traits. In temperate zones and high latitudes, bats increase their body mass (M
b
) in autumn to store fat reserves and use them during hibernation. However, other small mammals decrease their M
b
prior to winter to reduce the energetic requirements of individuals. These changes are unknown for bats inhabiting other highly energetic demanding environments. We measured changes in M
b
of 84 non-reproductive males of Eptesicus fuscus inhabiting a tropical montane ecosystem in central Mexico over seasons. We also examined the relationship of bats’ M
b
with the minimum ambient temperature (T
a
, °C) and mean precipitation (mm). Bats presented an increase in M
b
from March to June, followed by a decrease from September to November and presented the lowest M
b
from November to March, in the dry-cold season. The results suggest that the pattern of changes in M
b
could be the result of two non-exclusive components related to the bats’ energy budget, the energetic demands experienced by the bats throughout the year and the morphological adaptations animals could display to reduce their energy requirements during the winter.
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Affiliation(s)
- Kevin I. Medina-Bello
- Doctorado en Ciencias Biológicas , Universidad Autónoma de Tlaxcala , código postal 90062 , Tlaxcala de Xicohténcatl , Mexico
| | - Rommy Vázquez-Fuerte
- Escuela Nacional de Estudios Superiores, Unidad Morelia , Universidad Nacional Autónoma de México , apartado postal 58089 , Morelia , Michoacán , Mexico
| | - Jorge Ayala-Berdon
- CONACYT , Universidad Autónoma de Tlaxcala , código postal 90062 , Tlaxcala de Xicohténcatl , Mexico
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6
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Eastick DL, Griffiths SR, Yen JDL, Robert KA. Size at Birth, Postnatal Growth, and Reproductive Timing in an Australian Microbat. Integr Org Biol 2022; 4:obac030. [PMID: 36060865 PMCID: PMC9436771 DOI: 10.1093/iob/obac030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/10/2022] [Accepted: 07/27/2022] [Indexed: 11/28/2022] Open
Abstract
Reproductive phenology, size at birth, and postnatal growth are important life history traits that reflect parental investment. The ability to document detailed changes in these traits can be a valuable tool in the identification and management of at-risk wildlife populations. We examined reproductive traits in a common, widespread Australian microbat, Chalinolobus gouldii, at two sites over two years and derived growth curves and age estimation equations which will be useful in the study of how intrinsic and extrinsic factors alter parental investment strategies. We found that male and female offspring did not differ significantly in their size at birth or their postnatal growth rates. Bats born in 2018 were smaller at birth but grew at a faster rate than those born in 2017. When date of birth was compared across sites and years, we found bats born in 2018 had a later median birthdate (by 18 days) and births were more widespread than those born in 2017. Cooler and wetter weather during late gestation (Nov) in 2018 may have prolonged gestation and delayed births. With many bats facing threatening processes it is important to study reproductive plasticity in common and widespread “model” species, which may assist in the conservation and management of threatened microbats with similar reproductive traits.
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Affiliation(s)
- D L Eastick
- School of Agriculture, Biomedicine and Environment, La Trobe University , Melbourne, Victoria 3086
- Centre for Future Landscapes, La Trobe University , Melbourne, Victoria 3086
| | - S R Griffiths
- School of Agriculture, Biomedicine and Environment, La Trobe University , Melbourne, Victoria 3086
- Centre for Future Landscapes, La Trobe University , Melbourne, Victoria 3086
| | - J D L Yen
- Arthur Rylah Institute for Environmental Research, Department of Environment , Land, Water and Planning, Heidelberg, Victoria 3084
| | - K A Robert
- School of Agriculture, Biomedicine and Environment, La Trobe University , Melbourne, Victoria 3086
- Centre for Future Landscapes, La Trobe University , Melbourne, Victoria 3086
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7
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Flexible energy-saving strategies in female temperate-zone bats. J Comp Physiol B 2022; 192:805-814. [PMID: 35939092 PMCID: PMC9550788 DOI: 10.1007/s00360-022-01452-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 07/06/2022] [Accepted: 07/19/2022] [Indexed: 12/02/2022]
Abstract
Torpor is characterized by an extreme reduction in metabolism and a common energy-saving strategy of heterothermic animals. Torpor is often associated with cold temperatures, but in the last decades, more diverse and flexible forms of torpor have been described. For example, tropical bat species maintain a low metabolism and heart rate at high ambient and body temperatures. We investigated whether bats (Nyctalus noctula) from the cooler temperate European regions also show this form of torpor with metabolic inhibition at high body temperatures, and whether this would be as pronounced in reproductive as in non-reproductive bats. We simultaneously measured metabolic rate, heart rate, and skin temperature in non-reproductive and pregnant females at a range of ambient temperatures. We found that they can decouple metabolic rate and heart rate from body temperature: they maintained an extremely low metabolism and heart rate when exposed to ambient temperatures changing from 0 to 32.5 °C, irrespective of reproductive status. When we simulated natural temperature conditions, all non-reproductive bats used torpor throughout the experiment. Pregnant bats used variable strategies from torpor, to maintaining normothermy, or a combination of both. Even a short torpor bout during the day saved up to 33% of the bats' total energy expenditure. Especially at higher temperatures, heart rate was a much better predictor of metabolic rate than skin temperature. We suggest that the capability to flexibly save energy across a range of ambient temperatures within and between reproductive states may be an important ability of these bats and possibly other temperate-zone heterotherms.
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8
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Balzer EW, Grottoli AD, Burns LE, Broders HG. Active season body mass patterns of little brown and northern myotis bats. Ecol Evol 2022. [DOI: 10.1002/ece3.9230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Evan W. Balzer
- Department of Biology University of Waterloo Waterloo Ontario Canada
| | - Adam D. Grottoli
- Department of Biology University of Waterloo Waterloo Ontario Canada
| | - Lynne E. Burns
- Environment and Climate Change Canada Edmonton Alberta Canada
| | - Hugh G. Broders
- Department of Biology University of Waterloo Waterloo Ontario Canada
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9
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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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10
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Antonova EP, Belkin VV, Ilyukha VA, Khizhkin EA, Kalinina SN. Seasonal Changes in Body Mass and Activity of Digestive Enzymes in Eptesicus nilssonii (Mammalia: Chiroptera: Vespertilionidae) during Hibernation. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s002209302204010x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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McGuire LP, Fuller NW, Haase CG, Silas KA, Olson SH. Lean Mass Dynamics in Hibernating Bats and Implications for Energy and Water Budgets. Physiol Biochem Zool 2022; 95:317-325. [DOI: 10.1086/720160] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Torpor/hibernation cycle may enhance the risk of insecticides for bats: an in vitro study. ACTA VET BRNO 2022. [DOI: 10.2754/avb202291010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Exposure to pollutants is considered one of the potential reasons of population declines in bats. In the context of previous studies, we managed to create and keep a wide collection of cell lines from European bat species. Liver cells were chosen for testing, as they represent the preferred model for toxicological studies. Bats are protected, cell lines replacing experimental animals thus represent a unique opportunity to examine effects of pollutants which animals are exposed to in their environments. Moreover, cell incubation temperature variation may simulate physiological states of heterothermic bats. Liver cell lines were cultivated to the required cell number. Exposure to five different concentrations of permethrin (PM) and imidacloprid (IMI) were used to determine cytotoxic effects of these pesticides on Nyctalus noctula-derived liver cells cultivated at 37 °C and 8 °C for 24 h. An assay based on the measurement of activity of lactate dehydrogenase released from damaged cells was used for quantitating cytotoxicity. Cytotoxicity of IMI ranged from 0% to 47% and from 56% to 67% at 37 °C and 8 °C, respectively. Cytotoxicity of PM ranged from 36% to 56% and from 43% to 88% at 37 °C and 8 °C, respectively. Permethrin was tested on the cells at an order of magnitude lower concentrations; even so, higher degree of cytotoxicity was recorded. Imidacloprid was more toxic to bat liver cells at a hibernation temperature than at body temperature of 37 °C.
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13
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Meier F, Grosche L, Reusch C, Runkel V, van Schaik J, Kerth G. Long-term individualized monitoring of sympatric bat species reveals distinct species- and demographic differences in hibernation phenology. BMC Ecol Evol 2022; 22:7. [PMID: 35090401 PMCID: PMC8796590 DOI: 10.1186/s12862-022-01962-6] [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] [Received: 07/27/2021] [Accepted: 01/13/2022] [Indexed: 11/21/2022] Open
Abstract
Background Hibernation allows species to conserve energy and thereby bridge unfavorable environmental conditions. At the same time, hibernation imposes substantial ecological and physiological costs. Understanding how hibernation timing differs within and between species can provide insights into the underlying drivers of this trade-off. However, this requires individualized long-term data that are often unavailable. Here, we used automatic monitoring techniques and a reproducible analysis pipeline to assess the individualized hibernation phenology of two sympatric bat species. Our study is based on data of more than 1100 RFID-tagged Daubenton’s bats (Myotis daubentonii) and Natterer’s bats (Myotis nattereri) collected over seven years at a hibernaculum in Germany. We used linear mixed models to analyze species-, sex- and age-specific differences in entrance, emergence and duration of the longest continuous period spent in the hibernaculum. Results Overall, Daubenton’s bats entered the hibernaculum earlier and emerged later than Natterer’s bats, resulting in a nearly twice as long hibernation duration. In both species, adult females entered earlier and emerged from hibernation later than adult males. Hibernation duration was shorter for juveniles than adults with the exception of adult male Natterer’s bats whose hibernation duration was shortest of all classes. Finally, hibernation timing differed among years, but yearly variations in entrance and emergence timing were not equally shifted in both species. Conclusions Our results suggest that even in sympatric species, and across sex and age classes, hibernation timing may be differentially affected by environmental conditions. This highlights the necessity of using individualized information when studying the impact of changing environments on hibernation phenology. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-01962-6.
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Affiliation(s)
- Frauke Meier
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany.
| | - Leo Grosche
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
| | - Christine Reusch
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany.,Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Volker Runkel
- BVF Bundesverband für Fledermauskunde Deutschland e.V., Erfurt, Germany
| | - Jaap van Schaik
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
| | - Gerald Kerth
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
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14
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Blanco MB, Greene LK, Klopfer PH, Lynch D, Browning J, Ehmke EE, Yoder AD. Body Mass and Tail Girth Predict Hibernation Expression in Captive Dwarf Lemurs. Physiol Biochem Zool 2022; 95:122-129. [PMID: 34986077 DOI: 10.1086/718222] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractHibernation, a metabolic strategy, allows individuals to reduce energetic demands in times of energetic deficits. Hibernation is pervasive in nature, occurring in all major mammalian lineages and geographical regions; however, its expression is variable across species, populations, and individuals, suggesting that trade-offs are at play. Whereas hibernation reduces energy expenditure, energetically expensive arousals may impose physiological burdens. The torpor optimization hypothesis posits that hibernation should be expressed according to energy availability. The greater the energy surplus, the lower the hibernation output. The thrifty female hypothesis, a variation of the torpor optimization hypothesis, states that females should conserve more energy because of their more substantial reproductive costs. Contrarily, if hibernation's benefits offset its costs, hibernation may be maximized rather than optimized (e.g., hibernators with greater fat reserves could afford to hibernate longer). We assessed torpor expression in captive dwarf lemurs, primates that are obligate, seasonal, and tropical hibernators. Across 4.5 mo in winter, we subjected eight individuals at the Duke Lemur Center to conditions conducive to hibernation, recorded estimates of skin temperature hourly (a proxy for torpor), and determined body mass and tail fat reserves bimonthly. Across and between consecutive weigh-ins, heavier dwarf lemurs spent less time in torpor and lost more body mass. At equivalent body mass, females spent more time torpid and better conserved energy than did males. Although preliminary, our results support the torpor optimization and thrifty female hypotheses, suggesting that individuals optimize rather than maximize torpor according to body mass. These patterns are consistent with hibernation phenology in Madagascar, where dwarf lemurs hibernate longer in more seasonal habitats.
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15
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Cable AB, Willcox EV, Leppanen C. Contaminant exposure as an additional stressor to bats affected by white-nose syndrome: current evidence and knowledge gaps. ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:12-23. [PMID: 34625892 DOI: 10.1007/s10646-021-02475-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
Bats are exposed to numerous threats including pollution and emerging diseases. In North America, the fungal disease white-nose syndrome (WNS) has caused declines in many bat species. While the mechanisms of WNS have received considerable research attention, possible influences of contaminants have not. Herein, we review what is known about contaminant exposure and toxicity for four species whose populations have been severely affected by WNS (Myotis sodalis, M. septentrionalis, M. lucifugus, and Perimyotis subflavus) and identify temporal and spatial data gaps. We determine that there is limited information about the effects of contaminants on bats, and many compounds that have been detected in these bat species have yet to be evaluated for toxicity. The four species examined were exposed to a wide variety of contaminants; however, large spatial and knowledge gaps limit our ability to evaluate if contaminants contribute to species-level declines and if contaminant exposure exacerbates infection by WNS.
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Affiliation(s)
- Ashleigh B Cable
- Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences, University of Tennessee, Knoxville, TN, 37996-1610, USA
| | - Emma V Willcox
- Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences, University of Tennessee, Knoxville, TN, 37996-1610, USA.
| | - Christy Leppanen
- Department of Ecology and Evolutionary Biology, 569 Dabney Hall, University of Tennessee, Knoxville, TN, 37996-1610, USA
- The Center for Tobacco Products, United States Food and Drug Administration, Silver Spring, MD, 20993-0002, USA
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16
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McGuire LP, Fuller NW, Dzal YA, Haase CG, Klüg-Baerwald BJ, Silas KA, Plowright RK, Lausen CL, Willis CKR, Olson SH. Interspecific variation in evaporative water loss and temperature response, but not metabolic rate, among hibernating bats. Sci Rep 2021; 11:20759. [PMID: 34675252 PMCID: PMC8531132 DOI: 10.1038/s41598-021-00266-x] [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: 06/08/2021] [Accepted: 10/08/2021] [Indexed: 11/30/2022] Open
Abstract
Hibernation is widespread among mammals in a variety of environmental contexts. However, few experimental studies consider interspecific comparisons, which may provide insight into general patterns of hibernation strategies. We studied 13 species of free-living bats, including populations spread over thousands of kilometers and diverse habitats. We measured torpid metabolic rate (TMR) and evaporative water loss (two key parameters for understanding hibernation energetics) across a range of temperatures. There was no difference in minimum TMR among species (i.e., all species achieved similarly low torpid metabolic rate) but the temperature associated with minimum TMR varied among species. The minimum defended temperature (temperature below which TMR increased) varied from 8 °C to < 2 °C among species. Conversely, evaporative water loss varied among species, with species clustered in two groups representing high and low evaporative water loss. Notably, species that have suffered population declines due to white-nose syndrome fall in the high evaporative water loss group and less affected species in the low evaporative water loss group. Documenting general patterns of physiological diversity, and associated ecological implications, contributes to broader understanding of biodiversity, and may help predict which species are at greater risk of environmental and anthropogenic stressors.
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Affiliation(s)
- Liam P McGuire
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada.
- Department of Biological Sciences, Texas Tech University, 2901 Main St, Lubbock, TX, 79409, USA.
| | - Nathan W Fuller
- Department of Biological Sciences, Texas Tech University, 2901 Main St, Lubbock, TX, 79409, USA
- Nongame and Rare Species Program, Texas Parks and Wildlife, Austin, TX, 78744, USA
| | - Yvonne A Dzal
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MB, R3B 2E9, Canada
| | - Catherine G Haase
- Department of Microbiology and Immunology, Montana State University, PO Box 173520, Bozeman, MT, 59717, USA
- Department of Biology, Austin Peay State University, PO Box 4718, Clarkesville, TN, 37044, USA
| | - Brandon J Klüg-Baerwald
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, S4S 0A2, Canada
| | - Kirk A Silas
- Wildlife Conservation Society, Health Program, 2300 Southern Blvd, Bronx, NY, 10460, USA
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, PO Box 173520, Bozeman, MT, 59717, USA
| | - Cori L Lausen
- Wildlife Conservation Society Canada, Bat Program, PO Box 606, Kaslo, BC, V0G 1M0, Canada
| | - Craig K R Willis
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MB, R3B 2E9, Canada
| | - Sarah H Olson
- Wildlife Conservation Society, Health Program, 2300 Southern Blvd, Bronx, NY, 10460, USA
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17
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Hranac CR, Haase CG, Fuller NW, McClure ML, Marshall JC, Lausen CL, McGuire LP, Olson SH, Hayman DTS. What is winter? Modeling spatial variation in bat host traits and hibernation and their implications for overwintering energetics. Ecol Evol 2021; 11:11604-11614. [PMID: 34522327 PMCID: PMC8427580 DOI: 10.1002/ece3.7641] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/31/2021] [Accepted: 04/09/2021] [Indexed: 01/05/2023] Open
Abstract
White-nose syndrome (WNS) has decimated hibernating bat populations across eastern and central North America for over a decade. Disease severity is driven by the interaction between bat characteristics, the cold-loving fungal agent, and the hibernation environment. While we further improve hibernation energetics models, we have yet to examine how spatial heterogeneity in host traits is linked to survival in this disease system. Here, we develop predictive spatial models of body mass for the little brown myotis (Myotis lucifugus) and reassess previous definitions of the duration of hibernation of this species. Using data from published literature, public databases, local experts, and our own fieldwork, we fit a series of generalized linear models with hypothesized abiotic drivers to create distribution-wide predictions of prehibernation body fat and hibernation duration. Our results provide improved estimations of hibernation duration and identify a scaling relationship between body mass and body fat; this relationship allows for the first continuous estimates of prehibernation body mass and fat across the species' distribution. We used these results to inform a hibernation energetic model to create spatially varying fat use estimates for M. lucifugus. These results predict WNS mortality of M. lucifugus populations in western North America may be comparable to the substantial die-off observed in eastern and central populations.
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Affiliation(s)
- C. Reed Hranac
- Molecular Epidemiology and Public Health LaboratoryHopkirk Research InstituteMassey UniversityPalmerston NorthNew Zealand
| | - Catherine G. Haase
- Department of Microbiology and ImmunologyMontana State UniversityBozemanMTUSA
- Present address:
Department of BiologyAustin Peay State UniversityClarksvilleTNUSA
| | - Nathan W. Fuller
- Department of Biological SciencesTexas Tech UniversityLubbockTXUSA
- Present address:
Texas Parks and Wildlife DepartmentNongame and Rare Species ProgramAustinTXUSA
| | | | | | | | - Liam P. McGuire
- Department of Biological SciencesTexas Tech UniversityLubbockTXUSA
- Present address:
Department of BiologyUniversity of WaterlooWaterlooONCanada
| | | | - David T. S. Hayman
- Molecular Epidemiology and Public Health LaboratoryHopkirk Research InstituteMassey UniversityPalmerston NorthNew Zealand
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18
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Johnson C, Brown DJ, Sanders C, Stihler CW. Long-term changes in occurrence, relative abundance, and reproductive fitness of bat species in relation to arrival of White-nose Syndrome in West Virginia, USA. Ecol Evol 2021; 11:12453-12467. [PMID: 34594512 PMCID: PMC8462164 DOI: 10.1002/ece3.7991] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 07/12/2021] [Accepted: 07/16/2021] [Indexed: 12/15/2022] Open
Abstract
White-nose syndrome (WNS) is a disease caused by the fungus Pseudogymnoascus destructans which has resulted in the deaths of millions of bats across eastern North America. To date, hibernacula counts have been the predominant means of tracking the spread and impact of this disease on bat populations. However, an understanding of the impacts of WNS on demographic parameters outside the winter season is critical to conservation and recovery of bat populations impacted by this disease. We used long-term monitoring data to examine WNS-related impacts to summer populations in West Virginia, where WNS has been documented since 2009. Using capture data from 290 mist-net sites surveyed from 2003 to 2019 on the Monongahela National Forest, we estimated temporal patterns in presence and relative abundance for each bat species. For species that exhibited a population-level response to WNS, we investigated post-WNS changes in adult female reproductive state and body mass. Myotis lucifugus (little brown bat), M. septentrionalis (northern long-eared bat), and Perimyotis subflavus (tri-colored bat) all showed significant decreases in presence and relative abundance during and following the introduction of WNS, while Eptesicus fuscus (big brown bat) and Lasiurus borealis (eastern red bat) responded positively during the WNS invasion. Probability of being reproductively active was not significantly different for any species, though a shift to earlier reproduction was estimated for E. fuscus and M. septentrionalis. For some species, body mass appeared to be influenced by the WNS invasion, but the response differed by species and reproductive state. Results suggest that continued long-term monitoring studies, additional research into impacts of this disease on the fitness of WNS survivors, and a focus on providing optimal nonwintering habitat may be valuable strategies for assessing and promoting recovery of WNS-affected bat populations.
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Affiliation(s)
- Catherine Johnson
- Monongahela National ForestU.S. Forest ServiceElkinsWest VirginiaUSA
- Region 1National Park ServiceNarragansettRhode IslandUSA
| | - Donald J. Brown
- School of Natural ResourcesWest Virginia UniversityMorgantownWest VirginiaUSA
- Northern Research StationU.S.D.A. Forest ServiceParsonsWest VirginiaUSA
| | | | - Craig W. Stihler
- West Virginia Division of Natural Resources (retired)ElkinsWest VirginiaUSA
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19
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McGuire LP, Fuller NW, Dzal YA, Haase CG, Silas KA, Willis CKR, Olson SH, Lausen CL. Similar hibernation physiology in bats across broad geographic ranges. J Comp Physiol B 2021; 192:171-181. [PMID: 34426856 DOI: 10.1007/s00360-021-01400-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 06/28/2021] [Accepted: 08/07/2021] [Indexed: 11/26/2022]
Abstract
Species with broad geographic ranges may experience varied environmental conditions throughout their range leading to local adaptation. Variation among populations reflects potential adaptability or plasticity, with implications for populations impacted by disease, climate change, and other anthropogenic influences. However, behavior may counteract divergent selection among populations. We studied intraspecific variation in hibernation physiology of Myotis lucifugus (little brown myotis) and Corynorhinus townsendii (Townsend's big-eared bat), two species of bats with large geographic ranges. We studied M. lucifugus at three hibernacula which spanned a latitudinal gradient of 1500 km, and C. townsendii from 6 hibernacula spread across 1200 km latitude and 1200 km longitude. We found no difference in torpid metabolic rate among populations of either species, nor was there a difference in the effect of ambient temperature among sites. Evaporative water loss was similar among populations of both species, with the exception of one C. townsendii pairwise site difference and one M. lucifugus site that differed from the others. We suggest the general lack of geographic variation is a consequence of behavioral microhabitat selection. As volant animals, bats can travel relatively long distances in search of preferred microclimates for hibernation. Despite dramatic macroclimate differences among populations, hibernating bats are able to find preferred microclimate conditions within their range, resulting in similar selection pressures among populations spread across wide geographic ranges.
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Affiliation(s)
- Liam P McGuire
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada.
- Department of Biological Sciences, Texas Tech University, 2901 Main St, Lubbock, TX, 79409, USA.
| | - Nathan W Fuller
- Department of Biological Sciences, Texas Tech University, 2901 Main St, Lubbock, TX, 79409, USA
- Nongame and Rare Species Program, Texas Parks and Wildlife, Austin, TX, 78744, USA
| | - Yvonne A Dzal
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MB, R3B 2E9, Canada
| | - Catherine G Haase
- Department of Microbiology and Immunology, Montana State University, PO Box 173520, Bozeman, MT, 59717, USA
- Department of Biology, Austin Peay State University, PO Box 4718, Clarkesville, TN, 37040, USA
| | - Kirk A Silas
- Health Program, Wildlife Conservation Society, Bronx, NY, USA
| | - Craig K R Willis
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MB, R3B 2E9, Canada
| | - Sarah H Olson
- Health Program, Wildlife Conservation Society, Bronx, NY, USA
| | - Cori L Lausen
- Western Canada Bat Program, Wildlife Conservation Society Canada, PO Box 606, Kaslo, BC, V0G 1M0, Canada
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20
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Schorr RA, Siemers JL. Population dynamics of little brown bats ( Myotis lucifugus) at summer roosts: Apparent survival, fidelity, abundance, and the influence of winter conditions. Ecol Evol 2021; 11:7427-7438. [PMID: 34188824 PMCID: PMC8216974 DOI: 10.1002/ece3.7573] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/24/2021] [Accepted: 03/29/2021] [Indexed: 11/06/2022] Open
Abstract
White-nose syndrome (WNS) has caused the death of millions of bats, but the impacts have been more difficult to identify in western North America. Understanding how WNS, or other threats, impacts western bats may require monitoring other roosts, such as maternity roosts and night roosts, where bats aggregate in large numbers.Little brown bats (Myotis lucifugus) are experiencing some of the greatest declines from WNS. Estimating survival and understanding population dynamics can provide valuable data for assessing population declines and informing conservation efforts.We conducted a 5-year mark-recapture study of two M. lucifugus roosts in Colorado. We used the robust design model to estimate apparent survival, fidelity, and abundance to understand population dynamics, and environmental covariates to understand how summer and winter weather conditions impact adult female survival. We compared the fidelity and capture probability of M. lucifugus between colonies to understand how bats use such roosts.Overwinter survival increased with the number of days with temperatures below freezing (β > 0.100, SE = 0.003) and decreased with the number of days with snow cover (β < -0.40, SE < 0.13). Adult female fidelity was higher at one maternity roost than the other. Overwinter and oversummer adult female survival was high (>0.90), and based on survival estimates and fungal-swabbing results, we believe these populations have yet to experience WNS.Recapture of M. lucifugus using antennas that continuously read passive integrated transponder tags allows rigorous estimation of bat population parameters that can elucidate trends in abundance and changes in survival. Monitoring populations at summer roosts can provide unique population ecology data that monitoring hibernacula alone may not. Because few adult males are captured at maternity colonies, and juvenile males have low fidelity, additional effort should focus on understanding male M. lucifugus population dynamics.
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Affiliation(s)
- Robert A. Schorr
- Colorado Natural Heritage ProgramColorado State UniversityFort CollinsCOUSA
| | - Jeremy L. Siemers
- Colorado Natural Heritage ProgramColorado State UniversityFort CollinsCOUSA
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21
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Ryu H, Kinoshita K, Joo S, Kim SS. Urinary creatinine varies with microenvironment and sex in hibernating Greater Horseshoe bats (Rhinolophus ferrumequinum) in Korea. BMC Ecol Evol 2021; 21:77. [PMID: 33947328 PMCID: PMC8094569 DOI: 10.1186/s12862-021-01802-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 04/22/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In temperate regions many small mammals including bats hibernate during winter. During hibernation these small mammals occasionally wake up (arouse) to restore electrolyte and water balance. However, field data on water stress and concentration of bodily fluids during hibernation is scarce. Urinary creatinine concentration has long been used to calibrate urinary hormone concentration due to its close correlation with urine concentration. Therefore, by investigating urinary creatinine concentration, we can estimate bodily fluid concentration. In this study, we investigated changes in urinary creatinine from greater horseshoe bats (Rhinolophus ferrumequinum) hibernating in abandoned mineshafts in two regions in South Korea. RESULTS We collected 74 urine samples from hibernating greater horseshoe bats from 2018 to 2019. We found that urinary creatinine concentration was higher in February and March and then declined in April. There were also indications of a sex difference in the pattern of change in creatinine concentration over the three months. Bats in the warmer and less humid mineshaft had higher urinary creatinine concentrations than bats in the colder and more humid mineshaft. CONCLUSIONS These results indicate that hibernating bats face water stress as urinary concentration increases during winter and that water stress may vary depending on the microenvironment. Sex differences in behaviour during hibernation may influence arousal frequency and result in sex differences in changes in urinary creatinine concentration as hibernation progresses. Although further behavioural and endocrinal investigations are needed, our study suggests that urinary creatinine concentration can be used as a proxy to estimate the hydration status of bats and the effect of sex and environmental factors on arousal patterns during hibernation.
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Affiliation(s)
- Heungjin Ryu
- School of Life Sciences, Ulsan National Institute of Science and Technology, UNIST- gil 50, 44919, Eonyang-eup, Ulju, Ulsan, Republic of Korea
- National Institute of Ecology, Geumgang-ro 1210, Maseo-myeon, 33657, Seocheon, Chungnam, Republic of Korea
- Primate Research Institute, Kyoto University, 41-2 Kanrin, 484-8506, Inuyama, Aichi, Japan
| | - Kodzue Kinoshita
- Wildlife Research Center, Kyoto University, 2-24 Tanaka-Sekiden, 606-8203, Sakyo, Kyoto, Japan
| | - Sungbae Joo
- National Institute of Ecology, Geumgang-ro 1210, Maseo-myeon, 33657, Seocheon, Chungnam, Republic of Korea
| | - Sun-Sook Kim
- National Institute of Ecology, Geumgang-ro 1210, Maseo-myeon, 33657, Seocheon, Chungnam, Republic of Korea.
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Abstract
The recent introduction of Pseudogymnoascus destructans (the fungal pathogen that causes white-nose syndrome in bats) from Eurasia to North America has resulted in the collapse of North American bat populations and restructured species communities. The long evolutionary history between P. destructans and bats in Eurasia makes understanding host life history essential to uncovering the ecology of P. destructans. In this Review, we combine information on pathogen and host biology to understand the patterns of P. destructans spread, seasonal transmission ecology, the pathogenesis of white-nose syndrome and the cross-scale impact from individual hosts to ecosystems. Collectively, this research highlights how early pathogen detection and quantification of host impacts has accelerated the understanding of this newly emerging infectious disease.
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Pretorius M, Markotter W, Kearney T, Seamark E, Broders H, Keith M. No Evidence of Pre-Hibernation or Pre-Migratory Body Mass Gain in Miniopterus natalensis in North-Eastern South Africa. JOURNAL OF VERTEBRATE BIOLOGY 2021. [DOI: 10.25225/jvb.20088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Mariëtte Pretorius
- Mammal Research Institute, Faculty of Natural and Agricultural Sciences, University of Pretoria, Hatfield, South Africa; e-mail: ,
| | - Wanda Markotter
- Department of Medical Virology, Faculty of Health Sciences, Centre for Viral Zoonoses, University of Pretoria, South Africa; e-mail:
| | | | | | - Hugh Broders
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada; e-mail:
| | - Mark Keith
- Mammal Research Institute, Faculty of Natural and Agricultural Sciences, University of Pretoria, Hatfield, South Africa; e-mail: ,
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24
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OUP accepted manuscript. J Mammal 2021. [DOI: 10.1093/jmammal/gyab170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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25
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Eastick DL, Edwards AM, Griffiths SR, Spencer SJ, Robert KA. Validation of quantitative magnetic resonance as a non-invasive measure of body composition in an Australian microbat. AUSTRALIAN MAMMALOGY 2021. [DOI: 10.1071/am19060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Body composition (the total amount of fat mass, lean mass, minerals and water that constitute the body) is an important measure for understanding an animal’s physiology, ecology and behaviour. Traditional measures of body composition require the animal to either be placed under anaesthetic, which is invasive and can be high-risk, or be euthanised, preventing the ability to perform repeated measures on the same individual. We aimed to validate quantitative magnetic resonance (QMR) as a non-invasive measure of body composition by comparing QMR scans with chemical carcass analysis (CCA) in Gould’s wattled bats (Chalinolobus gouldii). In addition, we compared a commonly used microbat body condition index (residuals of mass by forearm length) to CCA. We found that QMR is an accurate method of estimating body condition in Gould’s wattled bats after calibration with regression equations, and the condition index could accurately predict lean and water mass but was a poor predictor of fat mass. Using accurate, non-invasive, repeatable measures of body condition may have important implications for ecological research in the face of changing environments.
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26
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Parallel Accelerated Evolution in Distant Hibernators Reveals Candidate Cis Elements and Genetic Circuits Regulating Mammalian Obesity. Cell Rep 2020; 29:2608-2620.e4. [PMID: 31775032 PMCID: PMC6910134 DOI: 10.1016/j.celrep.2019.10.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/21/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022] Open
Abstract
Obesity is a clinical problem and an important adaptation in many species. Hibernating mammals, for example, become obese, insulin resistant, and hyperinsulinemic to store fat. Here, we combine comparative phylogenomics with large-scale human genome data to uncover candidate cis elements and genetic circuits in different cell types. The Fat Mass and Obesity (FTO) locus, the strongest genetic risk factor for human obesity, is an enriched site for hibernator pARs. Our results uncover noncoding cis elements with putative roles in obesity and hibernation. Obesity is a clinical problem but also an important adaptation in hibernators. By using comparative genomics approaches to analyze the genomes of hibernators from different clades and contrasting the results with human obesity risk loci, Ferris and Gregg found 364 conserved cis elements with putative roles in regulating obesity and hibernation.
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27
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Bandouchova H, Zukal J, Linhart P, Berkova H, Brichta J, Kovacova V, Kubickova A, Abdelsalam EEE, Bartonička T, Zajíčková R, Pikula J. Low seasonal variation in greater mouse-eared bat (Myotis myotis) blood parameters. PLoS One 2020; 15:e0234784. [PMID: 32634149 PMCID: PMC7340307 DOI: 10.1371/journal.pone.0234784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 06/02/2020] [Indexed: 11/19/2022] Open
Abstract
The greater mouse-eared bat (Myotis myotis) is a flagship species for the protection of hibernation and summer maternity roosts in the Western Palearctic region. A range of pathogenic agents is known to put pressure on populations, including the white-nose syndrome fungus, for which the species shows the highest prevalence and infection intensity of all European bat species. Here, we perform analysis of blood parameters characteristic for the species during its natural annual life cycle in order to establish reference values. Despite sexual dimorphism and some univariate differences, the overall multivariate pattern suggests low seasonal variation with homeostatic mechanisms effectively regulating haematology and blood biochemistry ranges. Overall, the species displayed a high haematocrit and haemoglobin content and high concentration of urea, while blood glucose levels in swarming and hibernating bats ranged from hypo- to normoglycaemic. Unlike blood pH, concentrations of electrolytes were wide ranging. To conclude, baseline data for blood physiology are a useful tool for providing suitable medical care in rescue centres, for studying population health in bats adapting to environmental change, and for understanding bat responses to stressors of conservation and/or zoonotic importance.
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Affiliation(s)
- Hana Bandouchova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Jan Zukal
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
| | - Petr Linhart
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Hana Berkova
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Jiri Brichta
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Veronika Kovacova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Aneta Kubickova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Ehdaa E. E. Abdelsalam
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Tomáš Bartonička
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
| | - Renata Zajíčková
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
- Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Jiri Pikula
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
- * E-mail:
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28
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Faure‐Lacroix J, Desrochers A, Imbeau L, Simard A. Long-term changes in bat activity in Quebec suggest climatic responses and summer niche partitioning associated with white-nose syndrome. Ecol Evol 2020; 10:5226-5239. [PMID: 32607146 PMCID: PMC7319131 DOI: 10.1002/ece3.6194] [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: 04/02/2019] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 11/24/2022] Open
Abstract
In North America, the greatest and most sudden threat to hibernating bats is white-nose syndrome (WNS), which has caused massive declines in populations since 2006. Other determinants of bat dynamics, such as the climate, and the effect of reduction in the number of individuals sharing foraging space and summer roosting habitat may have an effect on population dynamics. We analyzed transect acoustic bat surveys conducted with ultrasonic detectors in 16 regions in Quebec, Canada, between 2000 and 2015. We used piecewise regression to describe changes in activity over time for each species and a meta-analytic approach to measure its association with the North Atlantic Oscillation (NAO). As expected, mouse-eared bat (Myotis spp.) activity sharply declined after the onset of WNS, down by 79% after 3 years. In contrast, big brown/silver-haired bat activity increased over the same period, possibly due to a release of competition. Hoary bats and red bats remained present, although their activity did not increase. Myotis activity was positively correlated with a one-year lag to the NAO index, associated with cold conditions in winter, but warm autumns. Big brown/silver-haired and hoary bats were also more active during NAO-positive years but without a lag. We conclude that combinations of threats may create rapid shifts in community compositions and that a more balanced research agenda that integrates a wider range of threats would help better understand and manage those changes.
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Affiliation(s)
- Julie Faure‐Lacroix
- Centre d'étude de la forêtFaculté de foresteriede géographie et de géomatiqueUniversité LavalQuébec CityQCCanada
| | - André Desrochers
- Centre d'étude de la forêtFaculté de foresteriede géographie et de géomatiqueUniversité LavalQuébec CityQCCanada
| | - Louis Imbeau
- Centre d'étude de la forêtUQATRouyn‐NorandaQCCanada
| | - Anouk Simard
- Ministère des Forêts de la Faune et des Parc du QuébecQuebec Centre for Biodiversity ScienceQuébec CityQCCanada
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29
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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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Phenology of reproductive condition varies with age and spring weather conditions in male Myotis daubentonii and M. nattereri (Chiroptera: Vespertilionidae). Sci Rep 2020; 10:6664. [PMID: 32313091 PMCID: PMC7171103 DOI: 10.1038/s41598-020-63538-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 03/23/2020] [Indexed: 11/08/2022] Open
Abstract
We examine the extent to which intrinsic and extrinsic factors influence reproductive phenology in male bats at the population level. Using data from thirteen breeding seasons (2006-2018), encompassing the reproductive histories of 1546 Myotis daubentonii and 530 M. nattereri males, we compare rates of sexual maturation and the temporal distribution of phases of spermatogenesis between juvenile (born that season) and adult (born in previous seasons) males. We found that (i) higher proportions of M. daubentonii (50.81%) than M. nattereri (12.85%) became sexually mature as juveniles, (ii) the proportion of juveniles in reproductive condition per annum was influenced by spring weather conditions, (iii) in both species males that reached puberty as juveniles had higher body mass, on average, than immature juveniles, (iv) older males (aged ≥4 years old) commenced spermatogenesis earlier than young adult males (aged 1-3 years old), whilst juveniles that commenced spermatogenesis did so later in the year than adults, in both species, and (v) M. daubentonii commenced and completed spermatogenesis earlier than M. nattereri in the equivalent age class. Our findings suggest that selection pressure exists for early mating readiness and synchronisation with female receptivity.
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Affiliation(s)
- Justin G. Boyles
- Cooperative Wildlife Research Laboratory Center for Ecology, and School of Biological Sciences Southern Illinois University Carbondale IL USA
| | | | - Anna Blomberg
- Department of Biology University of Turku Vesilinnantie 520100Turku Finland
| | - Thomas M. Lilley
- Finnish Museum of Natural History University of Helsinki P. Rautatiekatu 1300100Helsinki Finland
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Fasel NJ, Kołodziej-Sobocińska M, Komar E, Zegarek M, Ruczyński I. Penis size and sperm quality, are all bats grey in the dark? Curr Zool 2019; 65:697-703. [PMID: 31857816 PMCID: PMC6911842 DOI: 10.1093/cz/zoy094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 12/04/2018] [Indexed: 11/12/2022] Open
Abstract
Penises play a key role in sperm transport and in stimulating female genitals. This should impact post-copulatory competition, and expose penis characteristics to sexual selective pressures. Studies of male genitalia have repeatedly reported negative static allometries, which mean that, within species, large males have disproportionally small genitals when compared with smaller individuals. Males of some sperm-storing bat species may stand as an exception to such a pattern by arousing from hibernation to copulate with torpid females. The selection for large penises might take place, if a long organ provides advantages during post-copulatory competition and/or if females have evolved mechanisms allowing the choice of sire, relying on characters other than pre-copulatory traits (e.g., penis size). In this study, we measured dimensions of the erected penis in 4 sperm-storing bat species. Furthermore, we collected sperm and evaluated the link between penis dimensions and sperm velocity. Our results revealed steep allometric slopes of the erected penis length in Barbastella barbastellus and an inverse allometry of penis head width in Myotis nattereri. More detailed studies of copulatory behavior are urgently needed to explain the range of observed scaling relations. Furthermore, penis head width correlates with sperm velocity in Plecotus auritus. For this last species, we propose that penis shape might act as a marker of male fertility.
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Affiliation(s)
- Nicolas Jean Fasel
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse, Berlin, Germany
| | | | - Ewa Komar
- Mammal Research Institute Polish Academy of Sciences, Białowieża, Poland
| | - Marcin Zegarek
- Mammal Research Institute Polish Academy of Sciences, Białowieża, Poland
| | - Ireneusz Ruczyński
- Mammal Research Institute Polish Academy of Sciences, Białowieża, Poland
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Frank CL, Davis AD, Herzog C. The evolution of a bat population with white-nose syndrome (WNS) reveals a shift from an epizootic to an enzootic phase. Front Zool 2019; 16:40. [PMID: 31827569 PMCID: PMC6889174 DOI: 10.1186/s12983-019-0340-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/15/2019] [Indexed: 11/10/2022] Open
Abstract
Background White-nose Syndrome (WNS) is a mycosis caused by a cutaneous infection with the fungus Pseudogymnoascus destructans (Pd). It produces hibernation mortality rates of 75-98% in 4 bats: Myotis lucifugus, M. septentrionalis, M. sodalis, and Perimyotis subflavus. These high mortality rates were observed during the first several years after the arrival of P. destructans at a hibernation site. Mortality is caused by a 60% decrease in torpor bout duration, which results in a premature depletion of depot fat prior to spring. Results Little is known about the long-term effects of Pd on torpor and mortality, thus we conducted a 9-year study on M. lucifugus at 5 of the hibernation sites where Pd first appeared in North America during the winter of 2007-08. The M. lucifugus hibernating at one of these sites one year after the arrival of Pd (2008-09) had: a) a mean torpor bout duration of 7.6 d, b) no depot fat reserves by March, and c) an apparent over-winter mortality rate of 88%. The M. lucifugus hibernating at this same site 6-9 years after the arrival of Pd, in contrast, had: a) a mean torpor bout duration of 14.7 d, b) depot fat remaining in March, and c) an apparent mortality rate of 50%. The number of M. lucifugus hibernating at 2 of these sites has consistently increased since 2010 and is now more than 3.0-fold higher than the number remaining after the winter of 2008-09. Conclusions These findings indicate that this population of M. lucifugus has evolved mechanisms to hibernate well in the presence of Pd, thus reducing over-winter mortality.
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Affiliation(s)
- Craig L Frank
- 1Department of Biological Sciences, Fordham University, The Louis Calder Center, P.O. Box 887, Armonk, NY 10504 USA
| | - April D Davis
- 2Griffin Laboratory, Wadsworth Center, New York State Department of Health, 5668 State Farm Road, Slingerlands, NY 12159 USA
| | - Carl Herzog
- 3New York State Department of Environmental Conservation, 625 Broadway, Albany, NY 12233 USA
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Ryan CC, Burns LE, Broders HG. Changes in underground roosting patterns to optimize energy conservation in hibernating bats. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0340] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Non-migratory bats in colder climates use hibernation to survive winter. By reducing metabolic rate (i.e., using torpor), bats can survive winter on stored fat reserves. During hibernation, bats arouse from torpor and may move within the hibernaculum, a process called “internal migration”. We hypothesized that internal migration occurs to optimize hibernation energetics in that bats move to select a microclimate to minimize energy expenditure both by seeking cooler areas of the hibernacula and avoiding those with large temperature fluctuations. Early in the winter, we observed that 62% of bats were roosting in the warmer, less energy efficient, deepest 50% of an abandoned mine hibernaculum. Late in the season, there was a shift towards the cooler entrance area, thereby decreasing energy demands during the torpid period, with 78% of bats in the mine roosting within 50 m of the entrance. Although there was no significant effect of hibernation period (i.e., early vs. late winter) on the number of bats in huddles, the largest huddles occurred close to the entrance in late winter. To fully understand and manage bat populations, it is important to understand that hibernation is a dynamic process with bats moving and interacting with one another throughout the season.
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Affiliation(s)
- Caleb C. Ryan
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Lynne E. Burns
- Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS B3H 4J1, Canada
| | - Hugh G. Broders
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Activity Patterns of Cave-Dwelling Bat Species During Pre-Hibernation Swarming and Post-Hibernation Emergence in the Central Appalachians. DIVERSITY 2019. [DOI: 10.3390/d11090159] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In North America, bat research efforts largely have focused on summer maternity colonies and winter hibernacula, leaving the immediate pre- and post-hibernation ecology for many species unstudied. Understanding these patterns and processes is critical for addressing potential additive impacts to White-nose Syndrome (WNS)-affected bats, as autumn is a time of vital weight gain and fat resources are largely depleted in early spring in surviving individuals. Our study sought to examine autumn and spring bat activity patterns in the central Appalachian Mountains around three hibernacula to better understand spatio-temporal patterns during staging for hibernation and post-hibernation migration in the post-WNS environment. From early September through November 2015 and 2016, and from early March through April 2016 and 2017, we assessed the effects of distance to hibernacula and ambient conditions on nightly bat activity for Myotis spp. and big brown bats (Eptesicus fuscus) using zero-crossing frequency division bat detectors near cave entrances and 1 km, 2 km, and 3 km distant from caves. Following identification of echolocation calls, we used generalized linear mixed effects models to examine patterns of activity across the landscape over time and relative to weather. Overall bat activity was low at all sample sites during autumn and spring periods except at sites closest to hibernacula. Best-supported models describing bat activity varied, but date and ambient temperatures generally appeared to be major drivers of activity in both seasons. Total activity for all species had largely ceased by mid-November. Spring bat activity was variable across the sampling season, however, some activity was observed as early as mid-March, almost a month earlier than the historically accepted emergence time regionally. Current timing of restrictions on forest management activities that potentially remove day-roosts near hibernacula when bats are active on the landscape may be mismatched with actual spring post-hibernation emergence. Adjustments to the timing of these restrictions during the spring may help to avoid potentially additive negative impacts on WNS-impacted bat species.
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Cornwell E, Elzinga DC, Stowe S, Capaldi A. Modeling vaccination strategies to control white-nose syndrome in little brown bat colonies. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2019.108724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Besler NK, Broders HG. Combinations of reproductive, individual, and weather effects best explain torpor patterns among female little brown bats ( Myotis lucifugus). Ecol Evol 2019; 9:5158-5171. [PMID: 31110669 PMCID: PMC6509385 DOI: 10.1002/ece3.5091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 12/07/2018] [Accepted: 02/25/2019] [Indexed: 01/20/2023] Open
Abstract
Heterothermic mammals can use torpor, a state of metabolic suppression, to conserve energy during times of limited food and poor environmental conditions. Females may use torpor throughout gestation and lactation; however, there are associated physiological and ecological costs with potential fitness consequences. Previous studies have controlled for, but not quantified the impact of interindividual variation on torpor patterns and understanding this may provide insight on why certain thermoregulatory responses are employed. The objective of this study was to identify and quantitatively characterize the intrinsic variables and weather conditions that best explain variation in torpor patterns among individual female little brown bats, Myotis lucifugus. We used temperature-sensitive radio-transmitters affixed to females to measure skin temperature patterns of 35 individuals roosting in bat boxes in the spring and summer. We used Bayesian multi-model inference to rank a priori-selected models and variables based on their explanatory power. Reproductive condition and interindividual effects best explained torpor duration and depth, and weather best explained torpor frequency. Of the reproductive conditions, lactating females used torpor for the shortest durations and at shallower depths (i.e., smallest drop in minimum T sk), while females in early spring (i.e., not-obviously-pregnant) used torpor for the longest and deepest. Among individuals, the greatest difference in effects on duration occurred between pregnant individuals, suggesting interindividual variation within reproductive condition. Increases in precipitation and wind were associated with a higher probability of torpor use. Our results provide further support that multiple variables explain torpor patterns and highlight the importance of including individual effects when studying thermoregulatory patterns in heterothermic species. OPEN RESEARCH BADGES This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://doi.org/10.5061/dryad.c04tj85.
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Affiliation(s)
- Nicole K. Besler
- Department of BiologySaint Mary's UniversityHalifaxNova ScotiaCanada
| | - Hugh G. Broders
- Department of BiologyUniversity of WaterlooWaterlooOntarioCanada
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Johnson JS, Lacki MJ, Fulton SA. Foraging patterns of Rafinesque’s big-eared bat in upland forests managed with prescribed fire. J Mammal 2019. [DOI: 10.1093/jmammal/gyz039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Joseph S Johnson
- Department of Biological Sciences, Ohio University, Athens, OH, USA
| | - Michael J Lacki
- Department of Forestry and Natural Resources, University of Kentucky, Lexington, KY, USA
| | - Shelby A Fulton
- Kentucky State Nature Preserves Commission, Frankfort, KY, USA
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39
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Blažek J, Zukal J, Bandouchova H, Berková H, Kovacova V, Martínková N, Pikula J, Řehák Z, Škrabánek P, Bartonička T. Numerous cold arousals and rare arousal cascades as a hibernation strategy in European Myotis bats. J Therm Biol 2019; 82:150-156. [PMID: 31128642 DOI: 10.1016/j.jtherbio.2019.04.002] [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: 09/03/2018] [Revised: 03/19/2019] [Accepted: 04/07/2019] [Indexed: 10/27/2022]
Abstract
Hibernating bats optimise the duration of torpor bouts and arousals in relation to hibernaculum microclimatic conditions and fat reserves. Clustering has significant physiological and ecological benefits, promoting successful hibernation of individuals. Such aggregations may help maintain optimal temperatures, allowing better energy utilisation than in solitarily bats. However, aroused bats in a cluster could conceivably disturb those still hibernating, starting an energy-demanding arousal process. Our study was conducted over two winters in two different hibernacula (cave and mine) in the Czech Republic, where Greater mouse-eared bats (Myotis myotis) have previously been diagnosed with white-nose syndrome. In 118 arousal episodes we recorded 193 individual arousals in which a warming phase was observed, 135 (69.9%) being cold arousals, where bats ceased increasing their body temperatures at ≤ 10 °C. The remaining arousals were standard normothermic arousals, where body (fur) surface temperatures reached > 20 °C. Cold arousals occurred during the mid- and late hibernation periods, suggesting they were a response to disturbance by a neighbour in the same cluster. Arousal cascades, where bats aroused in series, were rare (12.7%) and reached a maximum in mid-January. Our data suggest that Myotis bats prolong their torpor bouts using numerous cold arousals but few arousal cascades. Upon arrival of a bat, the clustered bats show tolerance to disturbing by conspecifics.
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Affiliation(s)
- Ján Blažek
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
| | - Jan Zukal
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic; Institute of Vertebrate Biology of the Czech Academy of Sciences v.v.i., Brno, Czech Republic
| | - Hana Bandouchova
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Hana Berková
- Institute of Vertebrate Biology of the Czech Academy of Sciences v.v.i., Brno, Czech Republic
| | - Veronika Kovacova
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Natália Martínková
- Institute of Vertebrate Biology of the Czech Academy of Sciences v.v.i., Brno, Czech Republic; Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Jiri Pikula
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Zdeněk Řehák
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
| | - Pavel Škrabánek
- Faculty of Electrical Engineering and Informatics, University of Pardubice, Pardubice, Czech Republic
| | - Tomáš Bartonička
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic.
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40
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Cheng TL, Gerson A, Moore MS, Reichard JD, DeSimone J, Willis CKR, Frick WF, Kilpatrick AM. Higher fat stores contribute to persistence of little brown bat populations with white-nose syndrome. J Anim Ecol 2019; 88:591-600. [PMID: 30779125 DOI: 10.1111/1365-2656.12954] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/30/2018] [Indexed: 11/28/2022]
Abstract
The persistence of populations declining from novel stressors depends, in part, on their ability to respond by trait change via evolution or plasticity. White-nose syndrome (WNS) has caused rapid declines in several North America bat species by disrupting hibernation behaviour, leading to body fat depletion and starvation. However, some populations of Myotis lucifugus now persist with WNS by unknown mechanisms. We examined whether persistence of M. lucifigus with WNS could be explained by increased body fat in early winter, which would allow bats to tolerate the increased energetic costs associated with WNS. We also investigated whether bats were escaping infection or resistant to infection as an alternative mechanism explaining persistence. We measured body fat in early and late winter during initial WNS invasion and 8 years later at six sites where bats are now persisting. We also measured infection prevalence and intensity in persisting populations. Infection prevalence was not significantly lower than observed in declining populations. However, at two sites, infection loads were lower than observed in declining populations. Body fat in early winter was significantly higher in four of the six persisting populations than during WNS invasion. Physiological models of energy use indicated that these higher fat stores could reduce WNS mortality by 58%-70%. These results suggest that differences in fat storage and infection dynamics have reduced the impacts of WNS in many populations. Increases in body fat provide a potential mechanism for management intervention to help conserve bat populations.
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Affiliation(s)
- Tina L Cheng
- Department of Ecology and Evolutionary Biology, University of California, UC Santa Cruz, California.,Bat Conservation International, Austin, Texas
| | - Alexander Gerson
- Department of Biology, University of Massachusetts, Amherst, Amherst, Massachusetts
| | - Marianne S Moore
- College of Integrative Science and Arts, Arizona State University, Mesa, Arizona
| | | | - Joely DeSimone
- Department of Biology, University of Massachusetts, Amherst, Amherst, Massachusetts
| | - Craig K R Willis
- Department of Biology and Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, Manitoba, Canada
| | - Winifred F Frick
- Department of Ecology and Evolutionary Biology, University of California, UC Santa Cruz, California.,Bat Conservation International, Austin, Texas
| | - Auston Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California, UC Santa Cruz, California
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41
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Dowling ZR, O'Dell DI. Bat Use of an Island off the Coast of Massachusetts. Northeast Nat (Steuben) 2018. [DOI: 10.1656/045.025.0302] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Zara R. Dowling
- Department of Environmental Conservation, University of Massachusetts-Amherst, Room 225, 160 Holdsworth Way, Amherst, MA 01003-9285
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Krishna A. Adiposity associated changes in serum glucose and adiponectin levels modulate ovarian steroidogenesis during delayed embryonic development in the fruit bat, Cynopterus sphinx. Gen Comp Endocrinol 2018; 262:1-11. [PMID: 29474936 DOI: 10.1016/j.ygcen.2018.02.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/12/2018] [Accepted: 02/19/2018] [Indexed: 01/27/2023]
Abstract
The aim of the present study was to evaluate the mechanism by which embryonic development in Cynopterus sphinx is impaired during the period of increased accumulation of white adipose tissue during winter scarcity of food. The change in the mass of white adipose tissue during adipogenesis showed significant positive correlation with the circulating glucose level. But increase in circulating glucose level during the adipogenesis showed negative correlation with circulating progesterone and adiponectin levels. The in vivo study showed increased glucose uptake by the adipose tissue during adipogenesis due to increased expression of insulin receptor (IR) and glucose transporter (GLUT) 4 proteins. This study showed decline in the adiponectin level during fat accumulation. In the in vitro study, ovary treated with high doses of glucose showed impaired progesterone synthesis. This is due to decreased glucose uptake mediated decrease in the expression of luteinizing hormone-receptor, steroidogenic acute regulatory protein, IR, GLUT4 and AdipoR1 proteins. But the ovary treated with adiponectin either alone or with higher concentration of glucose showed improvement in progesterone synthesis due to increased expression of IR, GLUT4 and AdipoR1 mediated increased glucose uptake. In conclusion, increased circulating glucose level prior to winter dormancy preferably transported to white adipose tissue for fat accumulation diverting glucose away from the ovary. Consequently the decreased availability of adiponectin and glucose to the ovary and utero-embryonic unit may be responsible for impaired progesterone synthesis and delayed embryonic development. The delayed embryonic development in Cynopterus sphinx may have evolved, in part, as a mechanism to prevent pregnancy loss during the period of decreased energy availability.
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Affiliation(s)
- Amitabh Krishna
- Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.
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43
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Ruoss S, Becker NI, Otto MS, Czirják GÁ, Encarnação JA. Effect of sex and reproductive status on the immunity of the temperate bat Myotis daubentonii. Mamm Biol 2018; 94:120-126. [PMID: 32218715 PMCID: PMC7091572 DOI: 10.1016/j.mambio.2018.05.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/22/2018] [Indexed: 12/17/2022]
Abstract
Studies of immunity in bat species are rare. However, it is important to determine immunological variations to identify factors influencing the health status of these endangered mammals from an evolutionary, ecological, conservation, and public health point of view. Immunity is highly variable and can be influenced by both internal (e.g. hormone levels, energy demand) and external factors (e.g. pathogens, climate). As bats have some peculiar ecological, energetic, and putative immunological characteristics, they are outstanding study organisms for ecoimmunological studies. We tested if (i) female bats have a higher immunity than males similar to most other mammalian species and (ii) individuals differ according to their energy demand (e.g. reproductive status). To study these questions, we sampled female and male Myotis daubentonii with different reproductive states and estimated their bacterial killing activity, hemolysis/hemagglutination titer, immunoglobulin G (IgG) concentration, and total and differential white blood cell counts. These methods characterize the cellular and humoral branches of both the adaptive and the innate immune responses of these individuals. Reproductively active males had lower cellular immunity compared to non-reproductive individuals. Pregnant females had increased IgG concentrations while hemolysis was enhanced during lactation. No clear trade-off between immunity and reproduction was found; instead immunity of males and female bats seems to be modulated differently due to varying hormonal and energetic states. Our data suggest that both adaptive and innate immunity as well as individual differences (i.e. sex and reproductive state) need to be considered to get a comprehensive overall picture of immunity in wild mammals.
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Affiliation(s)
- Sara Ruoss
- Mammalian Ecology Group, Department of Animal Ecology and Systematics, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ), 35392 Giessen, Germany
| | - Nina I. Becker
- Institute for Applied Animal Ecology and Ecoinformatics (inatu.re), Im Brühl 2, 35457 Lollar, Germany
| | - Matthias S. Otto
- Mammalian Ecology Group, Department of Animal Ecology and Systematics, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ), 35392 Giessen, Germany
| | - Gábor Á. Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Jorge A. Encarnação
- Mammalian Ecology Group, Department of Animal Ecology and Systematics, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ), 35392 Giessen, Germany
- Institute for Applied Animal Ecology and Ecoinformatics (inatu.re), Im Brühl 2, 35457 Lollar, Germany
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Bandouchova H, Bartonička T, Berkova H, Brichta J, Kokurewicz T, Kovacova V, Linhart P, Piacek V, Pikula J, Zahradníková A, Zukal J. Alterations in the health of hibernating bats under pathogen pressure. Sci Rep 2018; 8:6067. [PMID: 29666436 PMCID: PMC5904171 DOI: 10.1038/s41598-018-24461-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 04/04/2018] [Indexed: 12/24/2022] Open
Abstract
In underground hibernacula temperate northern hemisphere bats are exposed to Pseudogymnoascus destructans, the fungal agent of white-nose syndrome. While pathological and epidemiological data suggest that Palearctic bats tolerate this infection, we lack knowledge about bat health under pathogen pressure. Here we report blood profiles, along with body mass index (BMI), infection intensity and hibernation temperature, in greater mouse-eared bats (Myotis myotis). We sampled three European hibernacula that differ in geomorphology and microclimatic conditions. Skin lesion counts differed between contralateral wings of a bat, suggesting variable exposure to the fungus. Analysis of blood parameters suggests a threshold of ca. 300 skin lesions on both wings, combined with poor hibernation conditions, may distinguish healthy bats from those with homeostatic disruption. Physiological effects manifested as mild metabolic acidosis, decreased glucose and peripheral blood eosinophilia which were strongly locality-dependent. Hibernating bats displaying blood homeostasis disruption had 2 °C lower body surface temperatures. A shallow BMI loss slope with increasing pathogen load suggested a high degree of infection tolerance. European greater mouse-eared bats generally survive P. destructans invasion, despite some health deterioration at higher infection intensities (dependant on hibernation conditions). Conservation measures should minimise additional stressors to conserve constrained body reserves of bats during hibernation.
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Affiliation(s)
- Hana Bandouchova
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Tomáš Bartonička
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
| | - Hana Berkova
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Jiri Brichta
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Tomasz Kokurewicz
- Institute of Biology, Department of Vertebrate Ecology and Palaeontology, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Veronika Kovacova
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Petr Linhart
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Vladimir Piacek
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Jiri Pikula
- Department of Ecology and Diseases of Game, Fish and Bees, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic. .,CEITEC - Central European Institute of Technology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic.
| | - Alexandra Zahradníková
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jan Zukal
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
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45
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Abstract
Human obesity has a large genetic component, yet has many serious negative consequences. How this state of affairs has evolved has generated wide debate. The thrifty gene hypothesis was the first attempt to explain obesity as a consequence of adaptive responses to an ancient environment that in modern society become disadvantageous. The idea is that genes (or more precisely, alleles) predisposing to obesity may have been selected for by repeated exposure to famines. However, this idea has many flaws: for instance, selection of the supposed magnitude over the duration of human evolution would fix any thrifty alleles (famines kill the old and young, not the obese) and there is no evidence that hunter-gatherer populations become obese between famines. An alternative idea (called thrifty late) is that selection in famines has only happened since the agricultural revolution. However, this is inconsistent with the absence of strong signatures of selection at single nucleotide polymorphisms linked to obesity. In parallel to discussions about the origin of obesity, there has been much debate regarding the regulation of body weight. There are three basic models: the set-point, settling point and dual-intervention point models. Selection might act against low and high levels of adiposity because food unpredictability and the risk of starvation selects against low adiposity whereas the risk of predation selects against high adiposity. Although evidence for the latter is quite strong, evidence for the former is relatively weak. The release from predation ∼2-million years ago is suggested to have led to the upper intervention point drifting in evolutionary time, leading to the modern distribution of obesity: the drifty gene hypothesis. Recent critiques of the dual-intervention point/drifty gene idea are flawed and inconsistent with known aspects of energy balance physiology. Here, I present a new formulation of the dual-intervention point model. This model includes the novel suggestion that food unpredictability and starvation are insignificant factors driving fat storage, and that the main force driving up fat storage is the risk of disease and the need to survive periods of pathogen-induced anorexia. This model shows why two independent intervention points are more likely to evolve than a single set point. The molecular basis of the lower intervention point is likely based around the leptin pathway signalling. Determining the molecular basis of the upper intervention point is a crucial key target for future obesity research. A potential definitive test to separate the different models is also described.
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Affiliation(s)
- John R Speakman
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China .,Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK
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46
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Shively R, Barboza P, Doak P, Jung TS. Increased diet breadth of little brown bats (Myotis lucifugus) at their northern range limit: a multimethod approach. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The distribution of small mammals is constrained by extreme environmental demands and variable food supplies that are commonly incurred at northern latitudes. Little brown bats (Myotis lucifugus (Le Conte, 1831)) are at the northwestern limits of their range in Alaska (USA), where environmental demands are higher and prey availability is more seasonal than elsewhere in their range. We hypothesized that the little brown bat in interior Alaska has adjusted to these constraints by broadening its foraging niche, relative to that of southern conspecifics. We analyzed arthropod fragments (microhistology) in guano to describe prey composition to order. We compared the efficacy of evaluating diet by microhistology with DNA analysis and stable isotope analysis on guano and hair. Bats consumed aerial prey such as Lepidoptera (moths) and Diptera (true flies and mosquitoes), as well as terrestrial arthropods including Araneae (spiders). Shifts in the proportion of aerial prey in the diet were closely linked to ordinal day. Values for δ15N in hair indicated that bats were generalists in interior Alaska, coastal Alaska, and the Yukon (Canada), but significant outliers indicated that some individuals have distinct diets. The little brown bat’s flexibility in feeding strategies likely allows this species to sustain populations in arctic and subarctic regions.
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Affiliation(s)
- Rachel Shively
- Department of Biology and Wildlife and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Perry Barboza
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Patricia Doak
- Department of Biology and Wildlife and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Thomas S. Jung
- Yukon Department of Environment, Whitehorse, YT Y1A 2C6, Canada
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2P5, Canada
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47
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Mayberry HW, McGuire LP, Willis CKR. Body temperatures of hibernating little brown bats reveal pronounced behavioural activity during deep torpor and suggest a fever response during white-nose syndrome. J Comp Physiol B 2017; 188:333-343. [PMID: 28766065 DOI: 10.1007/s00360-017-1119-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 07/18/2017] [Accepted: 07/25/2017] [Indexed: 01/06/2023]
Abstract
Hibernating animals use torpor [reduced body temperature (T b) and metabolic rate] to reduce energy expenditure during winter. Periodic arousals to normal T b are energetically expensive, so hibernators trade off arousal benefits against energetic costs. This is especially important for bats with white-nose syndrome (WNS), a fungal disease causing increased arousal frequency. Little brown bats (Myotis lucifugus) with WNS show upregulation of endogenous pyrogens and sickness behaviour. Therefore, we hypothesized that WNS should cause a fever response characterized by elevated T b. Hibernators could also accrue some benefits of arousals with minimal T b increase, thus avoiding full arousal costs. We compared skin temperature (T sk) of captive Myotis lucifugus inoculated with the WNS-causing fungus to T sk of sham-inoculated controls. Infected bats re-warmed to higher T sk during arousals which is consistent with a fever response. Torpid T sk did not differ. During what we term "cold arousals", bats exhibited movement following T sk increases of only 2.2 ± 0.3 °C, compared to >20 °C increases during normal arousals. Cold arousals occurred in both infected and control bats, suggesting they are not a pathophysiological consequence of WNS. Fever responses are energetically costly and could exacerbate energy limitation and premature fat depletion for bats with WNS. Cold arousals could represent an energy-saving mechanism for both healthy and WNS-affected bats when complete arousals are unnecessary or too costly. A few cold arousals were observed mid-hibernation, typically in response to disturbances. Cold arousals may, therefore, represent a voluntary restriction of arousal temperature instead of loss of thermoregulatory control.
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Affiliation(s)
- Heather W Mayberry
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MB, R3B 2E9, Canada. .,Department of Ecology and Evolutionary Biology, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga, ON, L5L 1C6, Canada.
| | - Liam P McGuire
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MB, R3B 2E9, Canada.,Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA
| | - Craig K R Willis
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MB, R3B 2E9, Canada
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48
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Hatton JJ, Stevenson TJ, Buck CL, Duddleston KN. Diet affects arctic ground squirrel gut microbial metatranscriptome independent of community structure. Environ Microbiol 2017; 19:1518-1535. [PMID: 28251799 PMCID: PMC5417852 DOI: 10.1111/1462-2920.13712] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 02/24/2017] [Accepted: 02/24/2017] [Indexed: 12/24/2022]
Abstract
We examined the effect of diet on pre-hibernation fattening and the gut microbiota of captive arctic ground squirrels (Urocitellus parryii). We measured body composition across time and gut microbiota density, diversity and function prior to and after five-weeks on control, high-fat, low-fat (18%, 40% and 10% energy from fat, respectively), or restricted calorie (50% of control) diets. Squirrels fattened at the same rate and to the same degree on all diets. Additionally, we found no differences in gut microbiota diversity or short chain fatty acid production across time or with diet. Analysis of the gut microbial transcriptome indicated differences in community function among diet groups, but not across time, and revealed shifts in the relative contribution of function at a taxonomic level. Our results demonstrate that pre-hibernation fattening of arctic ground squirrels is robust to changes in diet and is accomplished by more than increased food intake. Although our analyses did not uncover a definitive link between host fattening and the gut microbiota, and suggest the squirrels may possess a gut microbial community structure that is unresponsive to dietary changes, studies manipulating diet earlier in the active season may yet uncover a relationship between host diet, fattening and gut microbiota.
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Affiliation(s)
| | | | - C. Loren Buck
- Northern Arizona University, Flagstaff, Arizona, 86011
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49
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Impacts of White-Nose Syndrome Observed During Long-Term Monitoring of a Midwestern Bat Community. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2017. [DOI: 10.3996/102016-jfwm-077] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
White-nose syndrome (WNS) is an emerging fungal disease suspected to have infected Indiana caves in the winter of 2010–2011. This disease places energetic strains on cave-hibernating bats by forcing them to wake and use energy reserves. It has caused >5.5 million bat deaths across eastern North America, and may be the driving force for extinction of certain bat species. White-nose syndrome infection can be identified in hibernacula, but it may be difficult to determine whether bats in a particular area are affected if no known hibernacula exist. Thus, our aim was to use long-term monitoring data to examine changes in a summer population away from hibernacula that may be attributable to WNS effects during winter. We used capture data from a long-term bat-monitoring project in central Indiana with data from 10 repeatedly netted sites consistent across all reproductive periods. We modeled capture data by WNS exposure probability to assess changes in relative abundance of common species and reproductive classes as WNS exposure probability increases. We base exposure probability on a cokriging spatial model that interpolated WNS infection from hibernaculum survey data. The little brown bat Myotis lucifugus, the Indiana bat M. sodalis, and the tri-colored bat Perimyotis subflavus suffered 12.5–79.6% declines; whereas, the big brown bat Eptesicus fuscus, the eastern red bat Lasiurus borealis, and the evening bat Nycticeius humeralis showed 11.5–50.5% increases. We caught more nonreproductive adult females and postlactating females when WNS exposure probabilities were high, suggesting that WNS is influencing reproductive success of affected species. We conclude that, in Indiana, WNS is causing species-specific declines and may have caused the local extinction of M. lucifugus. Furthermore, WNS-affected species appear to be losing pups or forgoing pregnancy. Ongoing long-term monitoring studies, especially those focusing on reproductive success, are needed to measure the ultimate impacts of WNS.
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50
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Bartonička T, Bandouchova H, Berková H, Blažek J, Lučan R, Horáček I, Martínková N, Pikula J, Řehák Z, Zukal J. Deeply torpid bats can change position without elevation of body temperature. J Therm Biol 2016; 63:119-123. [PMID: 28010809 DOI: 10.1016/j.jtherbio.2016.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 10/20/2022]
Abstract
Because body temperature is tightly coupled to physiological function, hibernating animals entering deep torpor are typically immobile. We analysed thermal behaviour and locomotory activity of hibernating greater mouse-eared bats Myotis myotis and found two types of movement behaviour related to body temperature, i.e. movement at high fur temperature and at low fur temperatures (Tflow; <5°C). First Tflow movements appeared at the beginning of March and often occurred during long torpor bouts. In most cases, Tflow events represented slow displacements between clusters of bats. In several cases, however, departure or arrivals from and into clusters was also recorded without any elevation in body temperature. Distance travelled, flight duration and speed of locomotion during Tflow events was lower than in high fur temperature events. Such behaviour could allow bats to save energy long-term and prolong torpor bouts. Tflow movement in torpid bats significantly changes our understanding of basic hibernation principles and we strongly recommend further studies on the subject.
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Affiliation(s)
- Tomáš Bartonička
- Department of Botany and Zoology, Masaryk University, Brno, Czechia.
| | - Hana Bandouchova
- Department of Ecology and Diseases of Game, Fish and Bees; University of Veterinary and Pharmaceutical Sciences, Brno, Czechia
| | - Hana Berková
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czechia
| | - Ján Blažek
- Department of Botany and Zoology, Masaryk University, Brno, Czechia
| | - Radek Lučan
- Faculty of Science, Charles University in Prague, Prague, Czechia
| | - Ivan Horáček
- Faculty of Science, Charles University in Prague, Prague, Czechia
| | - Natália Martínková
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czechia; Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Jiri Pikula
- Department of Ecology and Diseases of Game, Fish and Bees; University of Veterinary and Pharmaceutical Sciences, Brno, Czechia
| | - Zdeněk Řehák
- Department of Botany and Zoology, Masaryk University, Brno, Czechia; Faculty of Education, Masaryk University, Brno, Czech Republic
| | - Jan Zukal
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czechia
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