1
|
Findlay-Robinson R, Hill DL. Hibernation nest site selection but not overwinter activity is associated with microclimatic conditions in a hibernating mammal. J Therm Biol 2024; 123:103909. [PMID: 39084175 DOI: 10.1016/j.jtherbio.2024.103909] [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: 11/24/2023] [Revised: 06/30/2024] [Accepted: 07/02/2024] [Indexed: 08/02/2024]
Abstract
Fine-scale variation in microclimates between habitats may impact energy consumption for the organisms that inhabit them. This may be particularly important for sedentary species or those unable to change habitats for long periods, such as hibernators. Low ambient temperatures were traditionally thought key to microclimatic selection for hibernation locations, but recent research suggests that other factors may contribute or exceed ambient temperature in importance. We aimed to characterise microclimates at hibernacula of wild hibernating hazel dormice Muscardinus avellanarius, and test how these microclimates differ to those at locations without hibernacula using a microclimatic modelling approach. Dormice hibernated in areas with warmer soil temperatures and lower variability in humidity and relative shortwave radiation. These results add to the growing body of evidence that low ambient temperatures may not be the primary driver of hibernation microclimate selection, although temperature is still likely to play an important role. We also found that ambient temperatures measured at the microclimatic level were substantially buffered compared to point samples taken at the nearest weather station (∼1.6 km away), highlighting the importance of considering microclimates in wildlife conservation in the face of future environmental change.
Collapse
Affiliation(s)
- Rachel Findlay-Robinson
- Institute of Science and Environment, University of Cumbria, Ambleside, Cumbria, LA22 9BB, UK.
| | - Davina L Hill
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK; School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050, South Africa.
| |
Collapse
|
2
|
Kuzmenko NV, Galagudza MM. Hormonal basis of seasonal metabolic changes in mammalian species. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 142:131-161. [PMID: 39059984 DOI: 10.1016/bs.apcsb.2024.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Seasonal changes in external conditions (photoperiod, meteorological conditions, diet) cause adaptive changes in both energy and substrate metabolism in the animals of mammalian species. In summer, long days and a rich diet contribute to relative elevation in the levels of thyroid hormones (TH), but warmer weather lowers their levels. In winter, short days and a poor diet inhibit TH synthesis, but low temperatures increase their secretion. In addition, the results of our meta-analyses revealed a significant role of atmospheric pressure in circannual fluctuations of metabolic parameters in humans. The changes in photoperiod are generally viewed as a major factor contributing to seasonal rhythm regulation However, numerous data show that season-dependent metabolic changes in mammals could be also accounted for by meteorological factors and diet.
Collapse
Affiliation(s)
- N V Kuzmenko
- Department for Experimental Physiology and Pharmacology, Almazov National Medical Research Centre, St. Petersburg, Russia.
| | - M M Galagudza
- Department for Experimental Physiology and Pharmacology, Almazov National Medical Research Centre, St. Petersburg, Russia
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Matthäus L, Kugelschafter K, Fietz J. Influence of ambient temperature on the phenology of the greater mouse-eared bat ( Myotis myotis). Ecol Evol 2023; 13:e10081. [PMID: 37214612 PMCID: PMC10196220 DOI: 10.1002/ece3.10081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 04/23/2023] [Accepted: 04/25/2023] [Indexed: 05/24/2023] Open
Abstract
In order to assess the consequences of climate change and evaluate its impacts on wildlife, it is essential to do so on a species-specific level. It is assumed that changes in the ambient temperature influence energy consumption as well as food availability and thus foraging behavior, reproduction, survival, and therefore population dynamics in bats. Based on this assumption, the present study aims to gain insights into the roosting and breeding behavior of the greater mouse-eared bat (Myotis myotis) in relation to changes of the ambient temperature. For this purpose, we investigated the effect of ambient temperature on the phenology of the greater mouse-eared bat by using activity data of the bats collected using light barriers at the maternity roosts. The light barrier used in this study is a system that detects the interruption of two light beams, for example, by a flying bat, and displays it as an electrical signal. The investigations have shown that the higher the winter temperatures, the earlier the greater mouse-eared bats returned to the roosts to form the maternity colony; however, this was only true for ambient temperatures below 0.5°C,birth season started earlier at higher spring temperatures,the dissolution of maternity roosts occurred earlier with earlier birth season and at higher ambient temperatures during lactation. The results revealed that ambient temperature has an influence on the phenology of the greater mouse-eared bat. Depending on the respective life history stage, an increase in ambient temperature can have a positive or negative effect on the fitness of the animals. In recent years, mild winters have been recorded more frequently, which can have an influence on the behavior of bats. Warm winters within certain limits seem to lead to an earlier formation of the maternity colony, which can be positive or negative for the bats depending on persistent weather conditions and thus insect availability. In the course of climate change, we can also expect earlier spring events and an increase in spring temperature, as well as hot spells in summer. These warm springs and summers seem to lead to an earlier beginning of births, a faster development of the juveniles and an earlier dissolution of the maternity roost. An advance of reproductive activities can be assumed to increase the chance to survive the following winter in both mothers and their young, as they have more time to build up sufficient energy reserves for hibernation before winter starts. Due to the climatic changes, phenological changes of the bats be expected. This study highlights that in order to understand the impact of climate change on biodiversity, it is necessary to investigate in detail effects on a species-specific level and also to consider direct and indirect effects of ambient temperature on different life history stages.
Collapse
Affiliation(s)
- Laura Matthäus
- Institute of BiologyUniversity of HohenheimStuttgartGermany
| | | | - Joanna Fietz
- Institute of BiologyUniversity of HohenheimStuttgartGermany
| |
Collapse
|
5
|
Koch M, Manecke J, Burgard JP, Münnich R, Kugelschafter K, Kiefer A, Veith M. How weather triggers the emergence of bats from their subterranean hibernacula. Sci Rep 2023; 13:6344. [PMID: 37072427 PMCID: PMC10113228 DOI: 10.1038/s41598-023-32166-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 03/23/2023] [Indexed: 05/03/2023] Open
Abstract
Hibernation is one of the most important behaviours of bats of the temperate zone. During winter, when little food or liquid water is available, hibernation in torpor lowers metabolic costs. However, the timing of emergence from hibernation is crucial for the resumption of the reproductive process in spring. Here, we investigate the spring emergence of six bat species or pairs of bat species of the genera Myotis and Plecotus at five hibernation sites in Central Europe over 5 years. Using generalized additive Poisson models (GAPMs), we analyze the influence of weather conditions (air and soil temperature, atmospheric pressure, atmospheric pressure trend, rain, wind, and cloud cover) as predictors of bat activity and separate these extrinsic triggers from residual motivation to emerge from hibernation (extrinsic factors not studied; intrinsic motivation). Although bats in a subterranean hibernaculum are more or less cut off from the outside world, all species showed weather dependence, albeit to varying degrees, with air temperature outside the hibernaculum having a significant positive effect in all species. The residual, potentially intrinsic motivation of species to emerge from their hibernacula corresponds to their general ecological adaptation, such as trophic specialization and roosting preferences. It allows the definition of three functional groups (high, medium and low residual activity groups) according to the degree of weather dependence of spring activity. A better knowledge of the interplay of extrinsic triggers and residual motivation (e.g., internal zeitgebers) for spring emergence will help to understand the flexibility of a species to adapt to a changing world.
Collapse
Affiliation(s)
- Martin Koch
- Department of Biogeography, Trier University, Universitätsring 15, 54296 Trier, Germany
| | - Julia Manecke
- Economics and Social Statistics Department, Trier University, Universitätsring 15, 54296 Trier, Germany
| | - Jan Pablo Burgard
- Economics and Social Statistics Department, Trier University, Universitätsring 15, 54296 Trier, Germany
| | - Ralf Münnich
- Economics and Social Statistics Department, Trier University, Universitätsring 15, 54296 Trier, Germany
| | | | - Andreas Kiefer
- Department of Biogeography, Trier University, Universitätsring 15, 54296 Trier, Germany
- NABU Rhineland-Palatinate, 55118 Mainz, Germany
| | - Michael Veith
- Department of Biogeography, Trier University, Universitätsring 15, 54296 Trier, Germany
| |
Collapse
|
6
|
Findlay‐Robinson R, Deecke VB, Weatherall A, Hill DL. Effects of climate change on life‐history traits in hibernating mammals. Mamm Rev 2023. [DOI: 10.1111/mam.12308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Rachel Findlay‐Robinson
- Institute of Science and the Environment, University of Cumbria, Ambleside Cumbria LA22 9BB UK
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences University of Glasgow Glasgow G12 8QQ UK
| | - Volker B. Deecke
- Institute of Science and the Environment, University of Cumbria, Ambleside Cumbria LA22 9BB UK
| | - Andrew Weatherall
- Institute of Science and the Environment, University of Cumbria, Ambleside Cumbria LA22 9BB UK
| | - Davina L. Hill
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences University of Glasgow Glasgow G12 8QQ UK
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Private Bag 3, Wits 2050 Johannesburg South Africa
| |
Collapse
|
7
|
Reusch C, Scheuerlein A, Grosche L, Meier F, Gampe J, Dammhahn M, van Schaik J, Kerth G. The risk faced by the early bat: individual plasticity and mortality costs of the timing of spring departure after hibernation. OIKOS 2023. [DOI: 10.1111/oik.09654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Christine Reusch
- Applied Zoology and Nature Conservation, Zoological Inst. and Museum, Univ. of Greifswald Greifswald Germany
- Dept of Evolutionary Ecology, Leibniz Inst. for Zoo and Wildlife Research Berlin Germany
| | - Alexander Scheuerlein
- Applied Zoology and Nature Conservation, Zoological Inst. and Museum, Univ. of Greifswald Greifswald Germany
| | - Leo Grosche
- Applied Zoology and Nature Conservation, Zoological Inst. and Museum, Univ. of Greifswald Greifswald Germany
| | - Frauke Meier
- Applied Zoology and Nature Conservation, Zoological Inst. and Museum, Univ. of Greifswald Greifswald Germany
| | - Jutta Gampe
- Laboratory of Statistical Demography, Max‐Planck Inst. for Demographic Research Rostock Germany
| | - Melanie Dammhahn
- Behavioural Biology, Inst. for Neurobiology and Univ. of Münster Münster Germany
| | - Jaap van Schaik
- Applied Zoology and Nature Conservation, Zoological Inst. and Museum, Univ. of Greifswald Greifswald Germany
| | - Gerald Kerth
- Applied Zoology and Nature Conservation, Zoological Inst. and Museum, Univ. of Greifswald Greifswald Germany
| |
Collapse
|
8
|
Summers JL, White JP, Kaarakka HM, Hygnstrom SE, Sedinger BS, Riddle J, Van Deelen T, Yahnke C. Influence of underground mining with explosives on a hibernating bat population. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Jennifer L. Summers
- Wisconsin Center for Wildlife, University of Wisconsin‐Stevens Point, Trainer Natural Resources Building Stevens Point Wisconsin USA
| | - John Paul White
- Wisconsin Department of Natural Resources Madison Wisconsin USA
| | | | - Scott E. Hygnstrom
- Wisconsin Center for Wildlife, University of Wisconsin‐Stevens Point, Trainer Natural Resources Building Stevens Point Wisconsin USA
| | - Benjamin S. Sedinger
- Wisconsin Center for Wildlife, University of Wisconsin‐Stevens Point, Trainer Natural Resources Building Stevens Point Wisconsin USA
| | - Jason Riddle
- Wisconsin Center for Wildlife, University of Wisconsin‐Stevens Point, Trainer Natural Resources Building Stevens Point Wisconsin USA
| | | | - Christopher Yahnke
- University of Wisconsin‐Stevens Point, Trainer Natural Resources Building Stevens Point Wisconsin USA
| |
Collapse
|
9
|
Power ML, Foley NM, Jones G, Teeling EC. Taking flight: An ecological, evolutionary and genomic perspective on bat telomeres. Mol Ecol 2022; 31:6053-6068. [PMID: 34387012 DOI: 10.1111/mec.16117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/21/2021] [Accepted: 08/03/2021] [Indexed: 01/31/2023]
Abstract
Over 20% of all living mammals are bats (order Chiroptera). Bats possess extraordinary adaptations including powered flight, laryngeal echolocation and a unique immune system that enables them to tolerate a diversity of viral infections without presenting clinical disease symptoms. They occupy multiple trophic niches and environments globally. Significant physiological and ecological diversity occurs across the order. Bats also exhibit extreme longevity given their body size with many species showing few signs of ageing. The molecular basis of this extended longevity has recently attracted attention. Telomere maintenance potentially underpins bats' extended healthspan, although functional studies are still required to validate the causative mechanisms. In this review, we detail the current knowledge on bat telomeres, telomerase expression, and how these relate to ecology, longevity and life-history strategies. Patterns of telomere shortening and telomerase expression vary across species, and comparative genomic analyses suggest that alternative telomere maintenance mechanisms evolved in the longest-lived bats. We discuss the unique challenges faced when working with populations of wild bats and highlight ways to advance the field including expanding long-term monitoring across species that display contrasting life-histories and occupy different environmental niches. We further review how new high quality, chromosome-level genome assemblies can enable us to uncover the molecular mechanisms governing telomere dynamics and how phylogenomic analyses can reveal the adaptive significance of telomere maintenance and variation in bats.
Collapse
Affiliation(s)
- Megan L Power
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Ireland
| | - Nicole M Foley
- Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - Gareth Jones
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Emma C Teeling
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Ireland
| |
Collapse
|
10
|
Balzer EW, Grottoli AD, Burns LE, Broders HG. Active season body mass patterns of little brown and northern myotis bats. Ecol Evol 2022; 12:e9230. [PMID: 39411583 PMCID: PMC11476244 DOI: 10.1002/ece3.9230] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 07/10/2022] [Accepted: 07/28/2022] [Indexed: 10/19/2024] Open
Abstract
Animals are expected to adjust their behavioral patterns to improve fitness outcomes, such as fecundity or offspring survival. For long-lived hibernators, decisions made in each annual cycle may reflect considerations not just for concurrent survival and reproduction but also the pressure to maximize overwinter survival and future reproductive success. We examined how these elements manifest themselves in the body mass variation patterns of North American northern latitude temperate bats, whose size and roosting habits present considerable monitoring challenges. We characterized and compared the summer and fall mass variation patterns of little brown myotis (Myotis lucifugus) and northern myotis (M. septentrionalis) from a historic dataset. In summer, the estimated date of parturition was strongly associated with spring foraging conditions (low wind, low precipitation, and warm temperatures), and mass gain associated with female reproduction conferred considerable differentiation between the mass variation patterns of females and males. In fall, differences were most apparent among species, although adults exhibited a greater capacity for rapid mass gain than juveniles. These results demonstrate how reproductive constraints and interannual survival have important influences on the behavior of temperate bats. Future work should seek to quantify the fitness benefits of patterns identified in this study, such as the rate of prehibernation mass gain.
Collapse
Affiliation(s)
- Evan W. Balzer
- Department of BiologyUniversity of WaterlooWaterlooOntarioCanada
| | - Adam D. Grottoli
- Department of BiologyUniversity of WaterlooWaterlooOntarioCanada
| | - Lynne E. Burns
- Environment and Climate Change CanadaEdmontonAlbertaCanada
| | - Hugh G. Broders
- Department of BiologyUniversity of WaterlooWaterlooOntarioCanada
| |
Collapse
|
11
|
Pettett CE, Salazar RD, Al-Hajri A, Al-Jabiri H, Macdonald DW, Yamaguchi N. Sex differences in the winter activity of desert hedgehogs (Paraechinus aethiopicus) in a resource-rich habitat in Qatar. Sci Rep 2022; 12:11118. [PMID: 35778424 PMCID: PMC9249915 DOI: 10.1038/s41598-022-15383-4] [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: 01/18/2022] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
Hedgehogs’ wide distribution and breadth of habitat use means they are a good model taxon for investigating behavioural responses to winter conditions, such as low temperatures and resource availability. We investigated the over-winter behaviour of desert hedgehogs (Paraechinus aethiopicus) in Qatar by radio-tracking 20 individuals and monitoring the body mass of 31 hedgehogs. Females spent more nights (38.63% of nights tracked) inactive than males (12.6%) and had lower monthly activity levels. The mean temperature on nights where hedgehogs were inactive was 14.9 °C compared with 17.0 °C when hedgehogs were active. By December, females lost a higher percentage of their November body mass than did males, but by February males had lost a higher percentage than females. We conclude that these sex differences in behaviour are a result of differing reproductive strategies with males becoming more active early in spring to search for mates, whereas female hedgehogs conserve energy for producing and raising young and avoid harassment by males. The winter activity of males may be facilitated by the resource-rich environment created by humans at this study site, and basking behaviour. This study highlights intraspecific and interspecific variation in behavioural strategies/tactics in response to winter conditions.
Collapse
Affiliation(s)
- Carly E Pettett
- WildCRU, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, OX13 5QL, UK
| | - Rosie D Salazar
- WildCRU, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, OX13 5QL, UK
| | - Afra Al-Hajri
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, PO Box 2713, Doha, Qatar
| | - Hayat Al-Jabiri
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, PO Box 2713, Doha, Qatar
| | - David W Macdonald
- WildCRU, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, OX13 5QL, UK
| | - Nobuyuki Yamaguchi
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, PO Box 2713, Doha, Qatar. .,Institute of Tropical Biodiversity and Sustainable Development, University of Malaysia Terengganu, 21030, Kuala Nerus, Malaysia.
| |
Collapse
|
12
|
Winter torpor expression varies in four bat species with differential susceptibility to white-nose syndrome. Sci Rep 2022; 12:5688. [PMID: 35383238 PMCID: PMC8983705 DOI: 10.1038/s41598-022-09692-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/28/2022] [Indexed: 01/11/2023] Open
Abstract
Studies examining the overwintering behaviors of North American hibernating bats are limited to a handful of species. We deployed temperature-sensitive transmitters on four species of bat that exhibit differences in their susceptibility to white nose syndrome (WNS; Myotis grisescens, M. leibii, M. sodalis, and Perimyotis subflavus) to determine if these differences are correlated with behavior exhibited during hibernation (i.e., torpor expression and arousal frequency). Mean torpor skin temperature (Tsk) and torpor bout duration varied significantly among species (P ≤ 0.024), but arousal Tsk and duration did not (P ≥ 0.057). One of the species with low susceptibility to WNS, M. leibii, had significantly shorter torpor bout durations (37.67 ± 26.89 h) than M. sodalis (260.67 ± 41.33 h), the species with medium susceptibility to WNS. Myotis leibii also had significantly higher torpor Tsk (18.57 °C ± 0.20) than M. grisescens (13.33 °C ± 0.60), a second species with low WNS susceptibility. The high susceptibility species, Perimyotis subflavus, exhibited low torpor Tsk (14.42 °C ± 0.36) but short torpor bouts (72.36 ± 32.16 h). We demonstrate that the four cavernicolous species examined exhibit a wide range in torpid skin temperature and torpor bout duration. Information from this study may improve WNS management in multispecies hibernacula or individual species management by providing insight into how some species may differ in their techniques for overwinter survival.
Collapse
|
13
|
Zukalova K, Seidlova V, Piacek V, Nemcova M, Pribyl M, Pikula J, Zukal J. One or two pups - optimal reproduction strategies of common noctule females. BMC ZOOL 2022; 7:18. [PMID: 37170295 PMCID: PMC10127298 DOI: 10.1186/s40850-022-00119-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/16/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The success of animal reproduction is impacted by a trade-off between energetic costs and mortality associated with immediate vs. future reproductive attempts. The reproductive strategies of European insectivorous bats differ from common mammalian standards due to the use of delayed fertilisation. Phenology of bat reproduction, including length of pregnancy, which may vary in the same species at different latitudes, between years at the same site or between individuals within a colony, is influenced by ecological conditions. To assess factors influencing the course of pregnancy, we evaluated levels of blood progesterone in 20 female common noctule bats Nyctalus noctula. The bats were individually tagged and randomly divided into two groups with different hibernation ending points (i.e. a control group vs. a treatment group with one-week longer hibernation). Following emergence from hibernation, the bats were kept in a wooden box at a stable temperature of 22 °C. RESULTS The majority of females gave birth to a single neonate (65%), but one female aborted her pups 2 days before the first successful births of other females. Based on development of progesterone concentration, we were able to define a number of different reproduction strategies, i.e. females with single offspring or twins, and females with supposed resorption of one embryo (embryonic mortality after implantation of the developing fertilised egg). Progesterone levels were much higher in females with two embryos during the first part of gestation and after birth. Progesterone levels were at their highest mid-gestation, with no difference between females carrying one or two foetuses. Length of gestation differed significantly between the two groups, with the longer hibernation (treatment) group having a roughly two-day shorter gestation period. CONCLUSIONS Female N. noctula are able to manipulate their litter size to balance immediate and future reproduction success. The estimated gestation length of approx. 49-days appears to be standard for N. noctula, with females optimising their thermoregulatory behaviour to keep the length of gestation as close to the standard as possible.
Collapse
Affiliation(s)
- Katerina Zukalova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic.
| | - Veronika Seidlova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic
| | - Vladimir Piacek
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic
| | - Monika Nemcova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic
| | - Michal Pribyl
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic
| | - Jiri Pikula
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic
| | - Jan Zukal
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Květná 8, 603 65, Brno, Czech Republic
- Department of Botany and Zoology, Masaryk University, Kotlářská 267/2, 611 37, Brno, Czech Republic
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Cold arousal - A mechanism used by hibernating bats to reduce the energetic costs of disturbance. J Therm Biol 2021; 101:103107. [PMID: 34879908 DOI: 10.1016/j.jtherbio.2021.103107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 09/13/2021] [Accepted: 09/17/2021] [Indexed: 11/21/2022]
Abstract
During the season of hibernation, temperate bats alternate between prolonged bouts of torpor with reduced body temperature and short arousals with a return to normothermy. Hibernating bats are sensitive to non-tactile stimuli and arouse following changes in microclimatic conditions or disturbance from other bats, potential predators, or humans. Here, we used temperature data loggers to register the skin temperature of 38 Myotis myotis bats over two winters (between January and March), during which regular visits were made to the hibernaculum. Two kinds of arousal were observed, normothermic (Tsk > 25 °C) and cold (Tsk < 15 °C). Although bats responded to the presence of a researcher by arousals of both kinds, cold arousals were more frequent (63.8%). We found that mass loss was not affected by the number of disturbances, however it was in positive relationship with the mass at the beginning of the observation and differed between sex and age categories. Furthermore normothermic bats crawling among cluster-mates initiated arousal cascades, which mainly consisted of cold arousals. We failed to detect any effect of age or sex on the number of arousals initiated by normothermic individuals. Warming by only a few degrees requires less energy than a normothermic arousal and we propose it is sufficient to activate the sensory system in order to assess the relevance of external stimuli. Our results indicate that cold arousals reflect a physiological and behavioural adaptation aimed at avoiding the energetic costs of disturbance that can lead to depletion of fat reserves.
Collapse
|
16
|
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: 7] [Impact Index Per Article: 2.3] [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.
Collapse
Affiliation(s)
- Robert A. Schorr
- Colorado Natural Heritage ProgramColorado State UniversityFort CollinsCOUSA
| | - Jeremy L. Siemers
- Colorado Natural Heritage ProgramColorado State UniversityFort CollinsCOUSA
| |
Collapse
|
17
|
Long-term patterns of cave-exiting activity of hibernating bats in western North America. Sci Rep 2021; 11:8175. [PMID: 33854126 PMCID: PMC8046793 DOI: 10.1038/s41598-021-87605-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 03/17/2021] [Indexed: 11/08/2022] Open
Abstract
Understanding frequency and variation of cave-exiting activity after arousal from torpor of hibernating bats is important for bat ecology and conservation, especially considering white-nose syndrome. In winter from 2011 to 2018, we acoustically monitored, and counted in hibernacula, two species of conservation concern-western small-footed myotis (Myotis ciliolabrum) and Townsend's big-eared bats (Corynorhinus townsendii)-in 9 caves located in important habitat for these species in western North America. We investigated if cave-exiting activity differed by species, cave, number of hibernating bats, moon phase, and weather variables. Both species exited hibernacula during all winter months, but most activity occurred in March followed by November. Although we counted almost 15 times more Townsend's big-eared bats during hibernacula surveys, we documented western small-footed myotis exiting caves 3 times more than Townsend's big-eared bats. Cave-exiting activity increased with increasing number of hibernating bats, but more so for western small-footed myotis. Both species of bats were active during warm weather and low wind speeds. Western small-footed myotis were more active during colder temperatures, higher wind speeds, and greater change in barometric pressure than Townsend's big-eared bats. Our results provide a long-term dataset of cave-exiting activity after arousal from torpor during hibernation for these species before the arrival of white-nose syndrome.
Collapse
|
18
|
Abstract
AbstractNatural hibernation sites used by bats in areas that lack cave features have long remained unresolved. To investigate hibernation site selection and winter activity of boreal bats, we recorded bat calls using passive acoustic monitoring at 16 sites in South-Western Finland. These sites included four rock outcrops with crevices and cave features, three glacial erratics or boulder fields, three ancient shores, three root cellars and three control sites where we did not expect bats to be overwintering. Our results revealed echolocation calls of Eptesicus nilssonii, Plecotus auritus and Myotis sp. We recorded significantly more activity near rock outcrops compared to other habitats, excluding root cellars. We also found that ambient temperature had a positive effect on bat activity and found evidence that P. auritus may be using low barometric pressure as a proxy for suitable foraging conditions during the winter. Our results suggest that rock outcrops may be more important to bats than previously acknowledged, highlighting the need to take these sites in account in planning of conservation measures. Furthermore, our findings underline the suitability of using acoustic monitoring in homing on hibernation sites that are not otherwise accessible.
Collapse
|
19
|
Green DM, Robbins LW. Seasonal Variation in Sex Ratio for Gray Bats (Myotis grisescens) at a Hibernaculum. Northeast Nat (Steuben) 2020. [DOI: 10.1656/045.027.0405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Dana M. Green
- Department of Biology, University of Regina, Laboratory Building LB109, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Lynn W. Robbins
- Department of Biology, Missouri State University, 901 S. National Avenue, Springfield, MO 65807
| |
Collapse
|
20
|
Lemieux-Labonté V, Dorville NASY, Willis CKR, Lapointe FJ. Antifungal Potential of the Skin Microbiota of Hibernating Big Brown Bats ( Eptesicus fuscus) Infected With the Causal Agent of White-Nose Syndrome. Front Microbiol 2020; 11:1776. [PMID: 32793178 PMCID: PMC7390961 DOI: 10.3389/fmicb.2020.01776] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/06/2020] [Indexed: 01/01/2023] Open
Abstract
Little is known about skin microbiota in the context of the disease white-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans (Pd), that has caused enormous declines of hibernating North American bats over the past decade. Interestingly, some hibernating species, such as the big brown bat (Eptesicus fuscus), appear resistant to the disease and their skin microbiota could play a role. However, a comprehensive analysis of the skin microbiota of E. fuscus in the context of Pd has not been done. In January 2017, we captured hibernating E. fuscus, sampled their skin microbiota, and inoculated them with Pd or sham inoculum. We allowed the bats to hibernate in the lab under controlled conditions for 11 weeks and then sampled their skin microbiota to test the following hypotheses: (1) Pd infection would not disrupt the skin microbiota of Pd-resistant E. fuscus; and (2) microbial taxa with antifungal properties would be abundant both before and after inoculation with Pd. Using high-throughput 16S rRNA gene sequencing, we discovered that beta diversity of Pd-inoculated bats changed more over time than that of sham-inoculated bats. Still, the most abundant taxa in the community were stable throughout the experiment. Among the most abundant taxa, Pseudomonas and Rhodococcus are known for antifungal potential against Pd and other fungi. Thus, in contrast to hypothesis 1, Pd infection destabilized the skin microbiota but consistent with hypothesis 2, bacteria with known antifungal properties remained abundant and stable on the skin. This study is the first to provide a comprehensive survey of skin microbiota of E. fuscus, suggesting potential associations between the bat skin microbiota and resistance to the Pd infection and WNS. These results set the stage for future studies to characterize microbiota gene expression, better understand mechanisms of resistance to WNS, and help develop conservation strategies.
Collapse
Affiliation(s)
| | - Nicole A. S.-Y. Dorville
- Department of Biology, Centre for Forest Interdisciplinary Research, The University of Winnipeg, Winnipeg, MB, Canada
| | - Craig K. R. Willis
- Department of Biology, Centre for Forest Interdisciplinary Research, The University of Winnipeg, Winnipeg, MB, Canada
| | | |
Collapse
|
21
|
Baloun DE, Webber QMR, McGuire LP, Boyles JG, Shrivastav A, Willis CKR. Testing the "Fasting While Foraging" Hypothesis: Effects of Recent Feeding on Plasma Metabolite Concentrations in Little Brown Bats ( Myotis lucifugus). Physiol Biochem Zool 2019; 92:373-380. [PMID: 31120325 DOI: 10.1086/704080] [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] [Indexed: 11/03/2022]
Abstract
Plasma metabolite concentrations can be used to understand nutritional status and foraging behavior across ecological contexts including prehibernation fattening, migration refueling, and variation in foraging habitat quality. Generally, high plasma concentrations of the ketone β-hydroxybutyrate, a product of fat catabolism, indicate fasting, while triglycerides indicate recent feeding and fat accumulation. In recent studies of insectivorous bats, triglyceride concentration increased after feeding as expected, but β-hydroxybutyrate also unexpectedly increased rather than decreased. An aerial-hawking foraging strategy is energetically demanding, and thus it has been hypothesized that foraging by insectivorous bats requires catabolism of stored fat. We tested this hypothesis by quantifying plasma β-hydroxybutyrate and triglyceride concentration following feeding in little brown bats (Myotis lucifugus) that were temporarily housed in individual cages to prevent flight. We provided a fixed amount of food and collected blood samples at different intervals after feeding to produce variation in plasma metabolite concentrations. Plasma triglyceride concentration responded as predicted, but similar to previous studies and contrary to our prediction, when flight was eliminated plasma β-hydroxybutyrate concentration responded similarly to triglyceride. Thus, it is unlikely that the unexpected plasma β-hydroxybutyrate patterns observed in previous studies were related to flight. The mechanism underlying this unexpected pattern remains unknown, but the response has been consistent in all studies to date. Thus, plasma metabolite analysis provides an effective tool for studies of nutritional status, although more work is needed to understand why insectivorous bats respond differently than other taxa.
Collapse
|
22
|
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.
Collapse
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
| |
Collapse
|
23
|
Haase CG, Fuller NW, Hranac CR, Hayman DTS, McGuire LP, Norquay KJO, Silas KA, Willis CKR, Plowright RK, Olson SH. Incorporating evaporative water loss into bioenergetic models of hibernation to test for relative influence of host and pathogen traits on white-nose syndrome. PLoS One 2019; 14:e0222311. [PMID: 31671100 PMCID: PMC6822741 DOI: 10.1371/journal.pone.0222311] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/08/2019] [Indexed: 12/29/2022] Open
Abstract
Hibernation consists of extended durations of torpor interrupted by periodic arousals. The ‘dehydration hypothesis’ proposes that hibernating mammals arouse to replenish water lost through evaporation during torpor. Arousals are energetically expensive, and increased arousal frequency can alter survival throughout hibernation. Yet we lack a means to assess the effect of evaporative water loss (EWL), determined by animal physiology and hibernation microclimate, on torpor bout duration and subsequent survival. White-nose syndrome (WNS), a devastating disease impacting hibernating bats, causes increased frequency of arousals during hibernation and EWL has been hypothesized to contribute to this increased arousal frequency. WNS is caused by a fungus, which grows well in humid hibernaculum environments and damages wing tissue important for water conservation. Here, we integrated the effect of EWL on torpor expression in a hibernation energetics model, including the effects of fungal infection, to determine the link between EWL and survival. We collected field data for Myotis lucifugus, a species that experiences high mortality from WNS, to gather parameters for the model. In saturating conditions, we predicted healthy bats experience minimal mortality. Infected bats, however, suffer high fungal growth in highly saturated environments, leading to exhaustion of fat stores before spring. Our results suggest that host adaptation to humid environments leads to increased arousal frequency from infection, which drives mortality across hibernaculum conditions. Our modified hibernation model provides a tool to assess the interplay between host physiology, hibernaculum microclimate, and diseases such as WNS on winter survival.
Collapse
Affiliation(s)
- Catherine G. Haase
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, United States of America
- * E-mail:
| | - Nathan W. Fuller
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States of America
| | - C. Reed Hranac
- Molecular Epidemiology and Public Health Laboratory, Hopkirk Research Institute, Massey University, Palmerston North, New Zealand
| | - David T. S. Hayman
- Molecular Epidemiology and Public Health Laboratory, Hopkirk Research Institute, Massey University, Palmerston North, New Zealand
| | - Liam P. McGuire
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States of America
| | | | - Kirk A. Silas
- Wildlife Conservation Society, Wildlife Health Program, Bronx, New York, United States of America
| | | | - Raina K. Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, United States of America
| | - Sarah H. Olson
- Wildlife Conservation Society, Wildlife Health Program, Bronx, New York, United States of America
| |
Collapse
|
24
|
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.
Collapse
|
25
|
Hume T, Geiser F, Currie SE, Körtner G, Stawski C. Responding to the weather: energy budgeting by a small mammal in the wild. Curr Zool 2019; 66:15-20. [PMID: 32467700 PMCID: PMC7245004 DOI: 10.1093/cz/zoz023] [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: 02/14/2019] [Accepted: 05/02/2019] [Indexed: 11/12/2022] Open
Abstract
Energy conservation is paramount for small mammals because of their small size, large surface area to volume ratio, and the resultant high heat loss to the environment. To survive on limited food resources and to fuel their expensive metabolism during activity, many small mammals employ daily torpor to reduce energy expenditure during the rest phase. We hypothesized that a small terrestrial semelparous marsupial, the brown antechinus Antechinus stuartii, would maximize activity when foraging conditions were favorable to gain fat reserves before their intense breeding period, but would increase torpor use when conditions were poor to conserve these fat reserves. Female antechinus were trapped and implanted with small temperature-sensitive radio transmitters to record body temperature and to quantify torpor expression and activity patterns in the wild. Most antechinus used torpor at least once per day over the entire study period. Total daily torpor use increased and mean daily body temperature decreased significantly with a reduction in minimum ambient temperature. Interestingly, antechinus employed less torpor on days with more rain and decreasing barometric pressure. In contrast to torpor expression, activity was directly related to ambient temperature and inversely related to barometric pressure. Our results reveal that antechinus use a flexible combination of physiology and behavior that can be adjusted to manage their energy budget according to weather variables.
Collapse
Affiliation(s)
- Taylor Hume
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia
| | - Shannon E Currie
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia.,Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, Berlin, 10315, Germany
| | - Gerhard Körtner
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia.,Department of Biology, Norwegian University of Science and Technology, Trondheim, 7491, Norway
| |
Collapse
|
26
|
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.
Collapse
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.
| |
Collapse
|
27
|
Haase CG, Fuller NW, Hranac CR, Hayman DTS, Olson SH, Plowright RK, McGuire LP. Bats are not squirrels: Revisiting the cost of cooling in hibernating mammals. J Therm Biol 2019; 81:185-193. [PMID: 30975417 DOI: 10.1016/j.jtherbio.2019.01.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/18/2018] [Accepted: 01/21/2019] [Indexed: 01/23/2023]
Abstract
Many species use stored energy to hibernate through periods of resource limitation. Hibernation, a physiological state characterized by depressed metabolism and body temperature, is critical to winter survival and reproduction, and therefore has been extensively quantified and modeled. Hibernation consists of alternating phases of extended periods of torpor (low body temperature, low metabolic rate), and energetically costly periodic arousals to normal body temperature. Arousals consist of multiple phases: warming, euthermia, and cooling. Warming and euthermic costs are regularly included in energetic models, but although cooling to torpid body temperature is an important phase of the torpor-arousal cycle, it is often overlooked in energetic models. When included, cooling cost is assumed to be 67% of warming cost, an assumption originally derived from a single study that measured cooling cost in ground squirrels. Since this study, the same proportional value has been assumed across a variety of hibernating species. However, no additional values have been derived. We derived a model of cooling cost from first principles and validated the model with empirical energetic measurements. We compared the assumed 67% proportional cooling cost with our model-predicted cooling cost for 53 hibernating mammals. Our results indicate that using 67% of warming cost only adequately represents cooling cost in ground squirrel-sized mammals. In smaller species, this value overestimates cooling cost and in larger species, the value underestimates cooling cost. Our model allows for the generalization of energetic costs for multiple species using species-specific physiological and morphometric parameters, and for predictions over variable environmental conditions.
Collapse
Affiliation(s)
- Catherine G Haase
- Department of Microbiology and Immunology, Montana State University, 109 Lewis Hall, PO Box 173520, Bozeman, MT 59717, USA.
| | - Nathan W Fuller
- Department of Biological Sciences, Texas Tech University, 2901 Main St., Lubbock, TX 79409, USA
| | - C Reed Hranac
- Molecular Epidemiology and Public Health Laboratory, Hopkirk Research Institute, Massey University, Private Bag, 11 222, Palmerston North 4442, New Zealand
| | - David T S Hayman
- Molecular Epidemiology and Public Health Laboratory, Hopkirk Research Institute, Massey University, Private Bag, 11 222, Palmerston North 4442, New Zealand
| | - Sarah H Olson
- Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, NY 10460, USA
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, 109 Lewis Hall, PO Box 173520, Bozeman, MT 59717, USA
| | - Liam P McGuire
- Department of Biological Sciences, Texas Tech University, 2901 Main St., Lubbock, TX 79409, USA
| |
Collapse
|
28
|
Neubaum DJ. Unsuspected retreats: autumn transitional roosts and presumed winter hibernacula of little brown myotis in Colorado. J Mammal 2018. [DOI: 10.1093/jmammal/gyy120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel J Neubaum
- Terrestrial Section, Colorado Parks and Wildlife, Independent Avenue, Grand Junction, CO, USA
| |
Collapse
|
29
|
Willis CKR. Trade-offs Influencing the Physiological Ecology of Hibernation in Temperate-Zone Bats. Integr Comp Biol 2018; 57:1214-1224. [PMID: 28985332 DOI: 10.1093/icb/icx087] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Seasonality of temperature and food availability can lead to trade-offs between the benefits of immediate reproduction and costs associated with mortality risk from starvation, inclement weather, or predation. Hibernating mammals exhibit an enormous seasonal shift in physiology and behavior and provide a useful system to examine the effect of this trade-off on key events in the annual cycle. Most of what we understand about the ecological energetics and phenology of hibernation comes from studies of rodent hibernators such as ground squirrels, chipmunks, and dormice. Temperate-zone, insectivorous bats, however, provide another useful model system to examine trade-offs influencing seasonal change within individuals. Here, I review recent studies from my laboratory on little brown bats (Myotis lucifugus) from central Canada to understand the interplay between capacity for energy storage, energy expenditure during hibernation, and the timing of key events in the annual cycle of hibernating mammals. These studies have relied on measurements of body condition to assess energetic status, biologging of skin temperature using temperature telemetry, and use of passive transponders (i.e., PIT tags) to quantify emergence timing. In general, these studies suggest that, in part due to constraints associated with flight, bats exhibit unique, or at least unusual, adaptations for extreme energy savings during winter. The results also support the optimization hypothesis that current energetic status and future energy requirements influence energy expenditure during hibernation and the timing of emergence from hibernation in spring. Taken together, this work provides insight into the influence of reproductive timing and energy availability on hibernation behavior and physiology. It also has implications for understanding responses of bat populations to anthropogenic impacts like climate change and white-nose syndrome.
Collapse
Affiliation(s)
- Craig K R Willis
- Department of Biology and Centre for Forest Inter-disciplinary Research, University of Winnipeg, 515 Portage Avenue, Winnipeg, Manitoba, Canada R3B2E9
| |
Collapse
|
30
|
Kizhina A, Uzenbaeva L, Antonova E, Belkin V, Ilyukha V, Khizhkin E. Hematological Parameters in Hibernating Eptesicus nilssonii (Mammalia: Chiroptera) Collected in Northern European Russia. ACTA CHIROPTEROLOGICA 2018. [DOI: 10.3161/15081109acc2018.20.1.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Aleksandra Kizhina
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya Street, 185910 Petrozavodsk, Karelia, Russia
| | - Lyudmila Uzenbaeva
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya Street, 185910 Petrozavodsk, Karelia, Russia
| | - Ekaterina Antonova
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya Street, 185910 Petrozavodsk, Karelia, Russia
| | - Vladimir Belkin
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya Street, 185910 Petrozavodsk, Karelia, Russia
| | - Viktor Ilyukha
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya Street, 185910 Petrozavodsk, Karelia, Russia
| | - Evgeniy Khizhkin
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya Street, 185910 Petrozavodsk, Karelia, Russia
| |
Collapse
|
31
|
Morales AE, Carstens BC. Evidence that Myotis lucifugus “Subspecies” are Five Nonsister Species, Despite Gene Flow. Syst Biol 2018; 67:756-769. [DOI: 10.1093/sysbio/syy010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 02/10/2018] [Indexed: 12/13/2022] Open
Affiliation(s)
- Ariadna E Morales
- Department of Evolution, Ecology and Organismal Biology, Ohio State University, 318 W. 12th Avenue, Columbus, OH 43210, USA
| | - Bryan C Carstens
- Department of Evolution, Ecology and Organismal Biology, Ohio State University, 318 W. 12th Avenue, Columbus, OH 43210, USA
| |
Collapse
|
32
|
Nowack J, Stawski C, Körtner G, Geiser F. Physiological and behavioral responses of an arboreal mammal to smoke and charcoal-ash substrate. Physiol Behav 2018; 184:116-121. [DOI: 10.1016/j.physbeh.2017.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/08/2017] [Accepted: 11/16/2017] [Indexed: 10/18/2022]
|
33
|
Barros PA, Ribeiro C, CAbral JA. Winter Activity of Bats in Mediterranean Peri-Urban Deciduous Forests. ACTA CHIROPTEROLOGICA 2017. [DOI: 10.3161/15081109acc2017.19.2.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Paulo A. Barros
- Laboratory of Applied Ecology, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Centre for the Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
| | - Cátia Ribeiro
- Laboratory of Applied Ecology, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
| | - João A. CAbral
- Laboratory of Applied Ecology, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Centre for the Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
| |
Collapse
|
34
|
Lemieux-Labonté V, Simard A, Willis CKR, Lapointe FJ. Enrichment of beneficial bacteria in the skin microbiota of bats persisting with white-nose syndrome. MICROBIOME 2017; 5:115. [PMID: 28870257 PMCID: PMC5584028 DOI: 10.1186/s40168-017-0334-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/28/2017] [Indexed: 05/09/2023]
Abstract
BACKGROUND Infectious diseases of wildlife are increasing worldwide with implications for conservation and human public health. The microbiota (i.e. microbial community living on or in a host) could influence wildlife disease resistance or tolerance. White-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans (Pd), has killed millions of hibernating North American bats since 2007. We characterized the skin microbiota of naïve, pre-WNS little brown bats (Myotis lucifugus) from three WNS-negative hibernation sites and persisting, previously exposed bats from three WNS-positive sites to test the hypothesis that the skin microbiota of bats shifts following WNS invasion. RESULTS Using high-throughput 16S rRNA gene sequencing on 66 bats and 11 environmental samples, we found that hibernation site strongly influenced the composition and diversity of the skin microbiota. Bats from WNS-positive and WNS-negative sites differed in alpha and beta diversity, as well as in microbiota composition. Alpha diversity was reduced in persisting, WNS-positive bats, and the microbiota profile was enriched with particular taxa such Janthinobacterium, Micrococcaceae, Pseudomonas, Ralstonia, and Rhodococcus. Some of these taxa are recognized for their antifungal activity, and specific strains of Rhodococcus and Pseudomonas are known to inhibit Pd growth. Composition of the microbial community in the hibernaculum environment and the community on bat skin was superficially similar but differed in relative abundance of some bacterial taxa. CONCLUSIONS Our results are consistent with the hypothesis that Pd invasion leads to a shift in the skin microbiota of surviving bats and suggest the possibility that the microbiota plays a protective role for bats facing WNS. The detection of what appears to be enrichment of beneficial bacteria in the skin microbiota of persisting bats is a promising discovery for species re-establishment. Our findings highlight not only the potential value of management actions that might encourage transmission, growth, and establishment of beneficial bacteria on bats, and within hibernacula, but also the potential risks of such management actions.
Collapse
Affiliation(s)
- Virginie Lemieux-Labonté
- Département de Sciences Biologiques, Université de Montréal, CP 6182, Succursale Centre-ville, Montréal, Québec, H2V 2S9, Canada.
- Quebec Centre for Biodiversity Science, CP 6182, Succursale Centre-ville, Montréal, Québec, H2V 2S9, Canada.
| | - Anouk Simard
- Direction de l'expertise sur la faune terrestre, l'herpétofaune et l'avifaune, Ministère des Forêts, de la Faune et des Parcs, Québec, Canada
- Quebec Centre for Biodiversity Science, CP 6182, Succursale Centre-ville, Montréal, Québec, H2V 2S9, Canada
| | - Craig K R Willis
- Department of Biology and Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, Manitoba, Canada
| | - François-Joseph Lapointe
- Département de Sciences Biologiques, Université de Montréal, CP 6182, Succursale Centre-ville, Montréal, Québec, H2V 2S9, Canada
- Quebec Centre for Biodiversity Science, CP 6182, Succursale Centre-ville, Montréal, Québec, H2V 2S9, Canada
| |
Collapse
|
35
|
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.
Collapse
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
| |
Collapse
|
36
|
Czenze ZJ, Jonasson KA, Willis CKR. Thrifty Females, Frisky Males: Winter Energetics of Hibernating Bats from a Cold Climate. Physiol Biochem Zool 2017. [DOI: 10.1086/692623] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
37
|
More functions of torpor and their roles in a changing world. J Comp Physiol B 2017; 187:889-897. [PMID: 28432393 PMCID: PMC5486538 DOI: 10.1007/s00360-017-1100-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/26/2016] [Accepted: 02/26/2017] [Indexed: 02/06/2023]
Abstract
Increased winter survival by reducing energy expenditure in adult animals is often viewed as the primary function of torpor. However, torpor has many other functions that ultimately increase the survival of heterothermic mammals and birds. In this review, we summarize new findings revealing that animals use torpor to cope with the conditions during and after natural disasters, including fires, storms, and heat waves. Furthermore, we suggest that torpor, which also prolongs longevity and was likely crucial for survival of mammals during the time of the dinosaur extinctions, will be advantageous in a changing world. Climate change is assumed to lead to an increase in the occurrence and intensity of climatic disasters, such as those listed above and also abnormal floods, droughts, and extreme temperatures. The opportunistic use of torpor, found in many heterothermic species, will likely enhance survival of these challenges, because these species can reduce energy and foraging requirements. However, many strictly seasonal hibernators will likely face the negative consequences of the predicted increase in temperature, such as range contraction. Overall, available data suggest that opportunistic heterotherms with their flexible energy requirements have an adaptive advantage over homeotherms in response to unpredictable conditions.
Collapse
|
38
|
Seasonal loss and resumption of circadian rhythms in hibernating arctic ground squirrels. J Comp Physiol B 2017; 187:693-703. [PMID: 28332018 DOI: 10.1007/s00360-017-1069-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/04/2017] [Accepted: 02/26/2017] [Indexed: 12/28/2022]
Abstract
Circadian clocks are near universal among organisms and play a key role in coordinating physiological and metabolic functions to anticipate or coincide with predictable daily changes in the physical and social environment. However, whether circadian rhythms persist and are functionally important during hibernation in all mammals is currently unclear. We examined whether circadian rhythms of body temperature (T b) persist during multi-day, steady-state torpor and investigated the association between timing of animal emergence, exposure to light, and resumption of activity and T b rhythms in free-living and captive male arctic ground squirrels. High-resolution (0.02 °C) temperature loggers revealed that circadian rhythms of T b were not present during deep torpor in free-living arctic ground squirrels. Significant circadian rhythms of T b resumed, however, following the resumption of euthermia, but prior to emergence, though rhythms became much more robust coincident with aboveground emergence. Additionally, squirrels maintained in captivity under conditions of constant darkness spontaneously developed significant circadian rhythms of T b and activity soon after ending torpor. Exposing animals to a 5-s pulse of light within a week when they ended torpor increased the strength of rhythms. Our results are consistent with the hypothesis that circadian clock function is inhibited during hibernation in arctic ground squirrels, and we postulate that exposure to external stimuli, such as light in free-living animals, and meals or acute disturbance for captive squirrels, may enhance T b rhythmicity by synchronizing loosely coupled circadian oscillators within the suprachiasmatic nucleus.
Collapse
|
39
|
McGuire L, Muise K, Shrivastav A, Willis C. No evidence of hyperphagia during prehibernation in a northern population of little brown bats (Myotis lucifugus). CAN J ZOOL 2016. [DOI: 10.1139/cjz-2016-0110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
During autumn, temperate bats must deposit fat stores for hibernation. Populations at high latitudes face four challenges: a shorter active season and shorter nights during the active season (less time to accumulate fat), a longer hibernation period (larger fat store needed), and colder nights (reduced prey availability). Mating also occurs during the prehibernation period, placing time constraints for mating and fattening on northern populations. We tested the hypothesis that these factors constrain prehibernation foraging in northern populations of little brown bats (Myotis lucifugus (Le Conte, 1831)). We measured plasma triglyceride concentration to study prehibernation fueling rates of a population near the northern range limit of the species and compared our results with previously published results from a more southern population. In contrast to bats at the lower latitude, we found consistently low concentrations of plasma triglycerides, indicating a low fuelling rate throughout the prehibernation period. However, despite an apparently low fuelling rate, bats achieved a substantially greater body mass. The discrepancy between populations suggests that environmental constraints lead northern populations to employ different behavioural or physiological strategies to prepare for hibernation.
Collapse
Affiliation(s)
- L.P. McGuire
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
| | - K.A. Muise
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
| | - A. Shrivastav
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
| | - C.K.R. Willis
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
- Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada
| |
Collapse
|
40
|
Klüg-Baerwald B, Gower L, Lausen C, Brigham R. Environmental correlates and energetics of winter flight by bats in southern Alberta, Canada. CAN J ZOOL 2016. [DOI: 10.1139/cjz-2016-0055] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Winter activity of bats is common, yet poorly understood. Other studies suggest a relationship between winter activity and ambient temperature, particularly temperature at sunset. We recorded echolocation calls to determine correlates of hourly bat activity in Dinosaur Provincial Park, Alberta, Canada. We documented bat activity in temperatures as low as −10.4 °C. We observed big brown bats (Eptesicus fuscus (Palisot de Beauvois, 1796)) flying at colder temperatures than species of Myotis bats (genus Myotis Kaup, 1829). We show that temperature and wind are important predictors of winter activity by E. fuscus and Myotis, and that Myotis may also use changes in barometric pressure to cue activity. In the absence of foraging opportunity, we suggest these environmental factors relate to heat loss and thus the energetic cost of flight. To understand the energetic consequences of bat flight in cold temperatures, we estimated energy expenditure during winter flights of E. fuscus and little brown myotis (Myotis lucifugus (Le Conte, 1831)) using species-specific parameters. We estimated that winter flight uses considerable fat stores and that flight thermogenesis could mitigate energetic costs by 20% or more. We also show that temperature-dependent interspecific differences in winter activity likely stem from differences between species in heat loss and potential for activity–thermoregulatory heat substitution.
Collapse
Affiliation(s)
- B.J. Klüg-Baerwald
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - L.E. Gower
- School of Biosciences, Sir Martin Evans Building, Cardiff University, Museum Avenue, Cardiff CF10 3AX, United Kingdom
| | - C.L. Lausen
- Wildlife Conservation Society Canada, P.O. Box 606, Kaslo, BC V0G 1M0, Canada
| | - R.M. Brigham
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| |
Collapse
|
41
|
Turner JM, Geiser F. The influence of natural photoperiod on seasonal torpor expression of two opportunistic marsupial hibernators. J Comp Physiol B 2016; 187:375-383. [DOI: 10.1007/s00360-016-1031-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/23/2016] [Accepted: 09/02/2016] [Indexed: 11/29/2022]
|
42
|
Meyer GA, Senulis JA, Reinartz JA. Effects of temperature and availability of insect prey on bat emergence from hibernation in spring. J Mammal 2016. [DOI: 10.1093/jmammal/gyw126] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
43
|
Abstract
Little is known about the ecology of many of the parasites and pathogens affecting bats, but host social behavior almost certainly plays an important role in bat-parasite dynamics. Understanding parasite dynamics for bats is important from a human public health perspective because of their role as natural reservoirs for recent high-profile emerging zoonotic pathogens (e.g. Ebola, Hendra) and from a bat conservation perspective because of the recent emergence of white-nose syndrome (WNS) in North America highlighting the potential population impacts of parasites and pathogens. Although some bat species are among the most gregarious of mammals, species vary widely in terms of their social behavior and this variation could influence pathogen transmission and impacts. Here, we review the literature on links between bat social behavior and parasite dynamics. Using standardized search terms in Web of Science, we identified articles that explicitly tested or discussed links between some aspect of bat sociality and parasite transmission or host population impacts. We identified social network analysis, epidemiological modeling, and interspecific comparative analyses as the most commonly used methods to quantify relationships between social behavior and parasite-risk in bats while WNS, Hendra virus, and arthropod ectoparasites were the most commonly studied host-parasite systems. We summarize known host-parasite relationships in these three systems and propose testable hypotheses that could improve our understanding of links between host sociality and parasite-dynamics in bats.
Collapse
Affiliation(s)
- Jorge Ortega
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| |
Collapse
|
44
|
Willis CKR. Conservation Physiology and Conservation Pathogens: White-Nose Syndrome and Integrative Biology for Host-Pathogen Systems. Integr Comp Biol 2015; 55:631-41. [PMID: 26307096 DOI: 10.1093/icb/icv099] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Conservation physiology aims to apply an understanding of physiological mechanisms to management of imperiled species, populations, or ecosystems. One challenge for physiologists hoping to apply their expertise to conservation is connecting the mechanisms we study, often in the laboratory, with the vital rates of populations in the wild. There is growing appreciation that infectious pathogens can threaten populations and species, and represent an important issue for conservation. Conservation physiology has much to offer in terms of addressing the threat posed to some host species by infectious pathogens. At the same time, the well-developed theoretical framework of disease ecology could provide a model to help advance the application of physiology to a range of other conservation issues. Here, I use white-nose syndrome (WNS) in hibernating North American bats as an example of a conservation problem for which integrative physiological research has been a critical part of research and management. The response to WNS highlights the importance of a well-developed theoretical framework for the application of conservation physiology to a particular threat. I review what is known about physiological mechanisms associated with mortality from WNS and emphasize the value of combining a strong theoretical background with integrative physiological studies in order to connect physiological mechanisms with population processes and thereby maximize the potential benefits of conservation physiology.
Collapse
Affiliation(s)
- Craig K R Willis
- Department of Biology and Centre for Forest Inter-disciplinary Research, University of Winnipeg, 515 Portage Avenue, Winnipeg, Manitoba Canada R3B2E9
| |
Collapse
|
45
|
Host demographic predicts ectoparasite dynamics for a colonial host during pre-hibernation mating. Parasitology 2015; 142:1260-9. [PMID: 26059507 DOI: 10.1017/s0031182015000542] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
SUMMARYParasite dynamics can be mediated by host behaviours such as sociality, and seasonal changes in aggregation may influence risk of parasite exposure. We used little brown bats (Myotis lucifugus) captured during the autumn mating/swarming period to test the hypothesis that seasonal and demographic-based variation in sociality affect ectoparasitism. We predicted that ectoparasitism would: (1) be higher for adult females and young of the year (YOY) than adult males because of female coloniality; (2) increase for adult males throughout swarming because of increasing contact with females; (3) decrease for adult females and YOY throughout swarming because of reduced coloniality and transmission of individual ectoparasites to males; (4) be similar for male and female YOY because vertical transmission from adult females should be similar. Ectoparasitism was lowest for adult males and increased for males during swarming, but some effects of demographic were unexpected. Contrary to our prediction, ectoparasitism increased for adult females throughout swarming and YOY males also hosted fewer ectoparasites compared with adult and YOY females. Interestingly, females in the best body condition had the highest parasite loads. Our results suggest that host energetic constraints associated with future reproduction affect pre-hibernation parasite dynamics in bats.
Collapse
|