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Valzania L, Alami A, Léopold P. A temporal allocation of amino acid resources ensures fitness and body allometry in Drosophila. Dev Cell 2024:S1534-5807(24)00336-8. [PMID: 38851190 DOI: 10.1016/j.devcel.2024.05.018] [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: 12/01/2023] [Revised: 03/29/2024] [Accepted: 05/15/2024] [Indexed: 06/10/2024]
Abstract
Organisms have evolved strategies to store resources and overcome periods of low or no nutrient access, including transient shortages or longer non-feeding developmental transitions. Holometabolous insects like Drosophila represent an attractive model to study resource allocation during development because they alternate feeding and non-feeding periods. Amino acids are essential components for tissue growth and renewal, but the strategies used for their storage remain largely unexplored. Here, we characterize the molecular mechanisms for the temporal production, accumulation, and use of specific storage proteins called hexamerins, and demonstrate their role in ensuring tissue formation and adult fitness. Moreover, we show that preventing hexamerin stores enhances the growth of early-developing organs while compromising the emergence of late-forming ones, consequently altering body allometry.
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Affiliation(s)
- Luca Valzania
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 26 rue d'Ulm, 75005 Paris, France.
| | - Aya Alami
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 26 rue d'Ulm, 75005 Paris, France
| | - Pierre Léopold
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 26 rue d'Ulm, 75005 Paris, France.
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2
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Noiret A, Karanewsky C, Aujard F, Terrien J. Sex-specific heterothermy patterns in wintering captive Microcebus murinus do not translate into differences in energy balance. J Therm Biol 2024; 121:103829. [PMID: 38569326 DOI: 10.1016/j.jtherbio.2024.103829] [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: 08/09/2023] [Revised: 02/28/2024] [Accepted: 02/28/2024] [Indexed: 04/05/2024]
Abstract
The physiological mechanisms of responses to stressors are at the core of ecophysiological studies that examine the limits of an organism's flexibility. Interindividual variability in these physiological responses can be particularly important and lead to differences in the stress response among population groups, which can affect population dynamics. Some observations of intersexual differences in heterothermy raise the question of whether there is a difference in energy management between the sexes. In this study, we assessed male and female differences in mouse lemurs (Microcebus murinus), a highly seasonal malagasy primate, by measuring their physiological flexibility in response to caloric restriction and examining the subsequent impact on reproductive success. Using complementary methods aiming to describe large-scale and daily variations in body temperature throughout a 6-month winter-like short-day (SD) period, we monitored 12 males and 12 females, applying chronic 40% caloric restriction (CR) to 6 individuals in each group. We found variations in Tb modulation throughout the SD period and in response to caloric treatment that depended on sex, as females, regardless of food restriction, and CR males, only, entered deep torpor. The use of deeper torpor, however, did not translate into a lower loss of body mass in females and did not affect reproductive success. Captive conditions may have buffered the depth of torpor and minimised the positive effects of torpor on energy savings. However, the significant sex differences in heterothermy we observed may point to physiological benefits other than preservation of energy reserves.
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Affiliation(s)
- Aude Noiret
- Unité Mécanismes Adaptatifs et Evolution (MECADEV), Muséum National D'Histoire Naturelle, CNRS UMR 7179, Brunoy, France.
| | - Caitlin Karanewsky
- Department of Biochemistry, Stanford University School of Medicine, California, 94305, USA
| | - Fabienne Aujard
- Unité Mécanismes Adaptatifs et Evolution (MECADEV), Muséum National D'Histoire Naturelle, CNRS UMR 7179, Brunoy, France
| | - Jérémy Terrien
- Unité Mécanismes Adaptatifs et Evolution (MECADEV), Muséum National D'Histoire Naturelle, CNRS UMR 7179, Brunoy, France.
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3
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Klüg-Baerwald BJ, Lausen CL, Burns SM, Brigham RM. Physiological and behavioural adaptations by big brown bats hibernating in dry rock crevices. J Comp Physiol B 2024; 194:203-212. [PMID: 38587619 DOI: 10.1007/s00360-024-01546-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 01/31/2024] [Accepted: 02/29/2024] [Indexed: 04/09/2024]
Abstract
Winter energy stores are finite and factors influencing patterns of activity are important for overwintering energetics and survival. Hibernation patterns (e.g., torpor bout duration and arousal frequency) often depend on microclimate, with more stable hibernacula associated with greater energy savings than less stable hibernacula. We monitored hibernation patterns of individual big brown bats (Eptesicus fuscus; Palisot de Beauvois, 1796) overwintering in rock-crevices that are smaller, drier, and less thermally stable than most known cave hibernacula. While such conditions would be predicted to increase arousal frequency in many hibernators, we did not find support for this. We found that bats were insensitive to changes in hibernacula microclimate (temperature and humidity) while torpid. We also found that the probability of arousal from torpor remained under circadian influence, likely because throughout the winter during arousals, bats commonly exit their hibernacula. We calculated that individuals spend most of their energy on maintaining a torpid body temperature a few degrees above the range of ambient temperatures during steady-state torpor, rather than during arousals as is typical of other small mammalian hibernators. Flight appears to be an important winter activity that may expedite the benefits of euthermic periods and allow for short, physiologically effective arousals. Overall, we found that big brown bats in rock crevices exhibit different hibernation patterns than conspecifics hibernating in buildings and caves.
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Affiliation(s)
- B J Klüg-Baerwald
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, S4S 0A2, Canada
| | - C L Lausen
- Wildlife Conservation Society Canada, PO Box 606, Kaslo, BC, V0G 1M0, Canada
| | - S M Burns
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, S4S 0A2, Canada
| | - R M Brigham
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, S4S 0A2, Canada.
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4
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Bornbusch SL, Power ML, Schulkin J, Drea CM, Maslanka MT, Muletz-Wolz CR. Integrating microbiome science and evolutionary medicine into animal health and conservation. Biol Rev Camb Philos Soc 2024; 99:458-477. [PMID: 37956701 DOI: 10.1111/brv.13030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
Microbiome science has provided groundbreaking insights into human and animal health. Similarly, evolutionary medicine - the incorporation of eco-evolutionary concepts into primarily human medical theory and practice - is increasingly recognised for its novel perspectives on modern diseases. Studies of host-microbe relationships have been expanded beyond humans to include a wide range of animal taxa, adding new facets to our understanding of animal ecology, evolution, behaviour, and health. In this review, we propose that a broader application of evolutionary medicine, combined with microbiome science, can provide valuable and innovative perspectives on animal care and conservation. First, we draw on classic ecological principles, such as alternative stable states, to propose an eco-evolutionary framework for understanding variation in animal microbiomes and their role in animal health and wellbeing. With a focus on mammalian gut microbiomes, we apply this framework to populations of animals under human care, with particular relevance to the many animal species that suffer diseases linked to gut microbial dysfunction (e.g. gut distress and infection, autoimmune disorders, obesity). We discuss diet and microbial landscapes (i.e. the microbes in the animal's external environment), as two factors that are (i) proposed to represent evolutionary mismatches for captive animals, (ii) linked to gut microbiome structure and function, and (iii) potentially best understood from an evolutionary medicine perspective. Keeping within our evolutionary framework, we highlight the potential benefits - and pitfalls - of modern microbial therapies, such as pre- and probiotics, faecal microbiota transplants, and microbial rewilding. We discuss the limited, yet growing, empirical evidence for the use of microbial therapies to modulate animal gut microbiomes beneficially. Interspersed throughout, we propose 12 actionable steps, grounded in evolutionary medicine, that can be applied to practical animal care and management. We encourage that these actionable steps be paired with integration of eco-evolutionary perspectives into our definitions of appropriate animal care standards. The evolutionary perspectives proposed herein may be best appreciated when applied to the broad diversity of species under human care, rather than when solely focused on humans. We urge animal care professionals, veterinarians, nutritionists, scientists, and others to collaborate on these efforts, allowing for simultaneous care of animal patients and the generation of valuable empirical data.
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Affiliation(s)
- Sally L Bornbusch
- Center for Conservation Genomics, Smithsonian's National Zoo and Conservation Biology Institute, 3001 Connecticut Ave. NW, Washington, DC, 20008, USA
- Department of Nutrition Science, Smithsonian's National Zoo and Conservation Biology Institute, 3001 Connecticut Ave. NW, Washington, DC, 20008, USA
| | - Michael L Power
- Center for Species Survival, Smithsonian's National Zoo and Conservation Biology Institute, Washington, 3001 Connecticut Ave. NW, Washington, DC, 20008, USA
| | - Jay Schulkin
- Department of Obstetrics & Gynecology, University of Washington School of Medicine, 1959 NE Pacific St., Box 356460, Seattle, WA, 98195, USA
| | - Christine M Drea
- Department of Evolutionary Anthropology, Duke University, 104 Biological Sciences, Campus Box 90383, Durham, NC, 27708, USA
| | - Michael T Maslanka
- Department of Nutrition Science, Smithsonian's National Zoo and Conservation Biology Institute, 3001 Connecticut Ave. NW, Washington, DC, 20008, USA
| | - Carly R Muletz-Wolz
- Center for Conservation Genomics, Smithsonian's National Zoo and Conservation Biology Institute, 3001 Connecticut Ave. NW, Washington, DC, 20008, USA
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5
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Muise KA, Dzal YA, Fletcher QE, Willis CKR. Hibernating female big brown bats (Eptesicus fuscus) adjust huddling and drinking behaviour, but not arousal frequency, in response to low humidity. J Exp Biol 2024; 227:jeb246699. [PMID: 38353043 PMCID: PMC10949064 DOI: 10.1242/jeb.246699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 02/07/2024] [Indexed: 03/08/2024]
Abstract
Many mammals hibernate during winter, reducing energy expenditure via bouts of torpor. The majority of a hibernator's energy reserves are used to fuel brief, but costly, arousals from torpor. Although arousals likely serve multiple functions, an important one is to restore water stores depleted during torpor. Many hibernating bat species require high humidity, presumably to reduce torpid water loss, but big brown bats (Eptesicus fuscus) appear tolerant of a wide humidity range. We tested the hypothesis that hibernating female E. fuscus use behavioural flexibility during torpor and arousals to maintain water balance and reduce energy expenditure. We predicted: (1) E. fuscus hibernating in dry conditions would exhibit more compact huddles during torpor and drink more frequently than bats in high humidity conditions; and (2) the frequency and duration of torpor bouts and arousals, and thus total loss of body mass would not differ between bats in the two environments. We housed hibernating E. fuscus in temperature- and humidity-controlled incubators at 50% or 98% relative humidity (8°C, 110 days). Bats in the dry environment maintained a more compact huddle during torpor and drank more frequently during arousals. Bats in the two environments had a similar number of arousals, but arousal duration was shorter in the dry environment. However, total loss of body mass over hibernation did not differ between treatments, indicating that the two groups used similar amounts of energy. Our results suggest that behavioural flexibility allows hibernating E. fuscus to maintain water balance and reduce energy costs across a wide range of hibernation humidities.
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Affiliation(s)
- Kristina A. Muise
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
| | - Yvonne A. Dzal
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
| | - Quinn E. Fletcher
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
| | - Craig K. R. Willis
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
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Gmutza HJ, Foster RW, Gmutza JM, Carter GG, Kurta A. Survival of hibernating little brown bats that are unaffected by white-nose syndrome: Using thermal cameras to understand arousal behavior. PLoS One 2024; 19:e0297871. [PMID: 38319950 PMCID: PMC10846716 DOI: 10.1371/journal.pone.0297871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Accepted: 01/09/2024] [Indexed: 02/08/2024] Open
Abstract
White-nose syndrome is a fungal disease that has decimated hibernating bats from multiple North American species. In 2014, the invasive fungus arrived at a hibernaculum of little brown bats (Myotis lucifugus) inside the spillway of Tippy Dam, located near Wellston, Michigan, USA, yet surprisingly, this population has not experienced the declines seen elsewhere. Unlike a typical subterranean hibernaculum, light enters the spillway through small ventilation holes. We hypothesized that this light causes the hibernating bats to maintain a circadian rhythm, thereby saving energy via social thermoregulation during synchronous arousals. To test this idea, we used high-resolution thermal cameras to monitor arousals from October 2019 to April 2020. We found that arousals followed a circadian rhythm, peaking after sunset, and that most observed arousals (>68%) occurred within a cluster of bats allowing for social thermoregulation. These findings are consistent with the hypothesis that light-induced synchronized arousals contribute to the unprecedented absence of mass mortality from white-nose syndrome in this large population. Using light to maintain a circadian rhythm in bats should be tested as a potential tool for mitigating mortality from white-nose syndrome. More generally, studying populations that have been largely unaffected by white-nose syndrome may provide insight into mitigation strategies for protecting the remaining populations.
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Affiliation(s)
- Haley J. Gmutza
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, United States of America
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Rodney W. Foster
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, United States of America
| | - Jonathan M. Gmutza
- eScape Technology LLC, Sterling Heights, Michigan, United States of America
| | - Gerald G. Carter
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio, United States of America
- Smithsonian Tropical Research Institute, Balboa Ancón, Panama
| | - Allen Kurta
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, United States of America
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7
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Haugg E, Borner J, Stalder G, Kübber‐Heiss A, Giroud S, Herwig A. Comparative transcriptomics of the garden dormouse hypothalamus during hibernation. FEBS Open Bio 2024; 14:241-257. [PMID: 37925593 PMCID: PMC10839406 DOI: 10.1002/2211-5463.13731] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/25/2023] [Accepted: 11/02/2023] [Indexed: 11/06/2023] Open
Abstract
Torpor or heterothermy is an energy-saving mechanism used by endotherms to overcome harsh environmental conditions. During winter, the garden dormouse (Eliomys quercinus) hibernates with multiday torpor bouts and body temperatures of a few degrees Celsius, interrupted by brief euthermic phases. This study investigates gene expression within the hypothalamus, the key brain area controlling energy balance, adding information on differential gene expression potentially relevant to orchestrate torpor. A de novo assembled transcriptome of the hypothalamus was generated from garden dormice hibernating under constant darkness without food and water at 5 °C. Samples were collected during early torpor, late torpor, and interbout arousal. During early torpor, 765 genes were differentially expressed as compared with interbout arousal. Twenty-seven pathways were over-represented, including pathways related to hemostasis, extracellular matrix organization, and signaling of small molecules. Only 82 genes were found to be differentially expressed between early and late torpor, and no pathways were over-represented. During late torpor, 924 genes were differentially expressed relative to interbout arousal. Despite the high number of differentially expressed genes, only 10 pathways were over-represented. Of these, eight were also observed to be over-represented when comparing early torpor and interbout arousal. Our results are largely consistent with previous findings in other heterotherms. The addition of a transcriptome of a novel species may help to identify species-specific and overarching torpor mechanisms through future species comparisons.
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Affiliation(s)
- Elena Haugg
- Institute of NeurobiologyUlm UniversityGermany
| | - Janus Borner
- Sackler Institute for Comparative GenomicsAmerican Museum of Natural HistoryNew YorkNYUSA
| | - Gabrielle Stalder
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife EcologyUniversity of Veterinary MedicineViennaAustria
| | - Anna Kübber‐Heiss
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife EcologyUniversity of Veterinary MedicineViennaAustria
| | - Sylvain Giroud
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife EcologyUniversity of Veterinary MedicineViennaAustria
- Energetics Lab, Department of BiologyNorthern Michigan UniversityMarquetteMIUSA
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8
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López-Roig M, Piera E, Serra-Cobo J. Thinner bats to face hibernation as response to climate warming. Sci Rep 2024; 14:2117. [PMID: 38267504 PMCID: PMC10808443 DOI: 10.1038/s41598-024-52459-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 01/18/2024] [Indexed: 01/26/2024] Open
Abstract
One of the principal consequences of climate warming on hibernating mammals could be the loss of optimal conditions for hibernation. Although hibernating mammals, like bats, may be particularly vulnerable to climate warming due to a potential reduction of energy saving during the hibernation, there is a lack of knowledge regarding how they will be affected and how they will respond to this impact. Here, we examine the variation in the body condition of Schreiber's bent-winged bat (Miniopterus schreibersii) to investigate changes in the optimization energy demand. Using a 20-year dataset (1998-2017), we analyse the temporal trends of body condition in three key stages of the hibernation period: onset and end of hibernation and early activity. Our results indicate that body condition at the onset and end of hibernation have decreased significantly over these 20 years. However, despite this lower body condition, the decrease of mass loss rate in the last decade (although not significant) indicate a greater saving of fat reserves. The significant increase in winter temperatures did not affect body condition or reserve depletion, instead, lower body condition was observed with a higher number of days below 0 °C. Unlike other hibernating bat species, the females had lower fat reserves than males in all three periods considered. This study indicates that hibernation energy requirements could be changing as an adaptation to a warmer climate and that hibernating bats can survive the winter by optimizing their lower accumulation of reserves.
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Affiliation(s)
- Marc López-Roig
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
- Institut de Recerca de Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Eduard Piera
- Infraestructures.Cat (Generalitat de Catalunya), C/dels Vergós, 36-42, 08017, Barcelona, Spain
| | - Jordi Serra-Cobo
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Institut de Recerca de Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
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9
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Allison AZT, Conway CJ, Morris AE, Goldberg AR, Lohr K, Richards R, Almack JA. Hit Snooze: An Imperiled Hibernator Assesses Spring Snow Conditions to Decide Whether to Terminate Hibernation or Reenter Torpor. ECOLOGICAL AND EVOLUTIONARY PHYSIOLOGY 2024; 97:53-63. [PMID: 38717368 DOI: 10.1086/729775] [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: 05/26/2024]
Abstract
AbstractMany animals follow annual cycles wherein physiology and behavior change seasonally. Hibernating mammals undergo one of the most drastic seasonal alterations of physiology and behavior, the timing of which can have significant fitness consequences. The environmental cues regulating these profound phenotypic changes will heavily influence whether hibernators acclimate and ultimately adapt to climate change. Hence, identifying the cues and proximate mechanisms responsible for hibernation termination timing is critical. Northern Idaho ground squirrels (Urocitellus brunneus)-a rare, endemic species threatened with extinction-exhibit substantial variation in hibernation termination phenology, but it is unclear what causes this variation. We attached geolocators to free-ranging squirrels to test the hypothesis that squirrels assess surface conditions in spring before deciding whether to terminate seasonal heterothermy or reenter torpor. Northern Idaho ground squirrels frequently reentered torpor following a brief initial emergence from hibernacula and were more likely to do so earlier in spring or when challenged by residual snowpack. Female squirrels reentered torpor when confronted with relatively shallow snowpack upon emergence, whereas male squirrels reentered torpor in response to deeper spring snowpack. This novel behavior was previously assumed to be physiologically constrained in male ground squirrels by testosterone production required for spermatogenesis and activated by the circannual clock. Assessing surface conditions to decide when to terminate hibernation may help buffer these threatened squirrels against climate change. Documenting the extent to which other hibernators can facultatively alter emergence timing by reentering torpor after emergence will help identify which species are most likely to persist under climate change.
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Wishart AE, Guerrero-Chacón AL, Smith R, Hawkshaw DM, McAdam AG, Dantzer B, Boutin S, Lane JE. Inferring condition in wild mammals: body condition indices confer no benefit over measuring body mass across ecological contexts. Oecologia 2024; 204:161-172. [PMID: 38180565 DOI: 10.1007/s00442-023-05495-7] [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: 04/06/2023] [Accepted: 11/30/2023] [Indexed: 01/06/2024]
Abstract
Many studies assume that it is beneficial for individuals of a species to be heavier, or have a higher body condition index (BCI), without accounting for the physiological relevance of variation in the composition of different body tissues. We hypothesized that the relationship between BCI and masses of physiologically important tissues (fat and lean) would be conditional on annual patterns of energy acquisition and expenditure. We studied three species with contrasting ecologies in their respective natural ranges: an obligate hibernator (Columbian ground squirrel, Urocitellus columbianus), a facultative hibernator (black-tailed prairie dog, Cynomys ludovicianus), and a food-caching non-hibernator (North American red squirrel, Tamiasciurus hudsonicus). We measured fat and lean mass in adults of both sexes using quantitative magnetic resonance (QMR). We measured body mass and two measures of skeletal structure (zygomatic width and right hind foot length) to develop sex- and species-specific BCIs, and tested the utility of BCI to predict body composition in each species. Body condition indices were more consistently, and more strongly correlated, with lean mass than fat mass. The indices were most positively correlated with fat when fat was expected to be very high (pre-hibernation prairie dogs). In all cases, however, BCI was never better than body mass alone in predicting fat or lean mass. While the accuracy of BCI in estimating fat varied across the natural histories and annual energetic patterns of the species considered, measuring body mass alone was as effective, or superior in capturing sufficient variation in fat and lean in most cases.
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Affiliation(s)
- Andrea E Wishart
- Department of Biology, University of Saskatchewan, Saskatoon, SK, S7N 5E2, Canada.
| | | | - Rebecca Smith
- Department of Biology, University of Saskatchewan, Saskatoon, SK, S7N 5E2, Canada
| | - Deborah M Hawkshaw
- Department of Biology, University of Saskatchewan, Saskatoon, SK, S7N 5E2, Canada
| | - Andrew G McAdam
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109-1043, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109-1043, USA
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, SK, S7N 5E2, Canada
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11
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Rowsey LE, Reeve C, Savoy T, Speers-Roesch B. Thermal constraints on exercise and metabolic performance do not explain the use of dormancy as an overwintering strategy in the cunner (Tautogolabrus adspersus). J Exp Biol 2024; 227:jeb246741. [PMID: 38044850 PMCID: PMC10906487 DOI: 10.1242/jeb.246741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 11/24/2023] [Indexed: 12/05/2023]
Abstract
Winter cold slows ectotherm physiology, potentially constraining activities and ecological opportunities at poleward latitudes. Yet, many fishes are winter-active, facilitated by thermal compensation that improves cold performance. Conversely, winter-dormant fishes (e.g. cunner, Tautogolabrus adspersus) become inactive and non-feeding overwinter. Why are certain fishes winter-dormant? We hypothesized that winter dormancy is an adaptive behavioural response arising in poleward species that tolerate severe, uncompensated constraints of cold on their physiological performance. We predicted that below their dormancy threshold of 7--8°C, exercise and metabolic performance of cunner are greatly decreased, even after acclimation (i.e. shows above-normal, uncompensated thermal sensitivity, Q10>1-3). We measured multiple key performance metrics (e.g. C-start maximum velocity, chase swimming speed, aerobic scope) in cunner after acute exposure to 26-2°C (3°C intervals using 14°C-acclimated fish) or acclimation (5-8 weeks) to 14-2°C (3°C intervals bracketing the dormancy threshold). Performance declined with cooling, and the acute Q10 of all six performance rate metrics was significantly greater below the dormancy threshold temperature (Q10,acute8-2°C=1.5-4.9, mean=3.3) than above (Q10,acute14-8°C=1.1-1.9, mean=1.5), inferring a cold constraint. However, 2°C acclimation (temporally more relevant to seasonal cooling) improved performance, abolishing the acute constraint (Q10,acclimated8-2°C=1.4-3.0, mean=2.0; also cf. Q10,acclimated14-8°C=1.2-2.9, mean=1.7). Thus, dormant cunner show partial cold-compensation of exercise and metabolic performance, similar to winter-active species. However, responsiveness to C-start stimuli was greatly cold-constrained even following acclimation, suggesting dormancy involves sensory limitation. Thermal constraints on metabolic and exercise physiology are not significant drivers of winter dormancy in cunner. In fact, compensatory plasticity at frigid temperatures is retained even in a dormant fish.
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Affiliation(s)
- Lauren E. Rowsey
- Department of Biological Sciences, University of New Brunswick Saint John, 100 Tucker Park Road, Saint John, NB E2L 4L5, Canada
| | - Connor Reeve
- Department of Biological Sciences, University of New Brunswick Saint John, 100 Tucker Park Road, Saint John, NB E2L 4L5, Canada
| | - Tyler Savoy
- Department of Biological Sciences, University of New Brunswick Saint John, 100 Tucker Park Road, Saint John, NB E2L 4L5, Canada
| | - Ben Speers-Roesch
- Department of Biological Sciences, University of New Brunswick Saint John, 100 Tucker Park Road, Saint John, NB E2L 4L5, Canada
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12
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Roberts KT, Szejner-Sigal A, Lehmann P. Seasonal energetics: are insects constrained by energy during dormancy? J Exp Biol 2023; 226:jeb245782. [PMID: 37921417 DOI: 10.1242/jeb.245782] [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: 11/04/2023]
Abstract
In seasonal environments, many animals, including insects, enter dormancy, where they are limited to a fixed energy budget. The inability to replenish energetic stores during these periods suggests insects should be constrained by pre-dormancy energy stores. Over the last century, the community of researchers working on survival during dormancy has operated under the strong assumption that energy limitation is a key fitness trait driving the evolution of seasonal strategies. That is, energy use has to be minimized during dormancy because insects otherwise run out of energy and die during dormancy, or are left with too little energy to complete development, reproductive maturation or other costly post-dormancy processes such as dispersal or nest building. But if energy is so strongly constrained during dormancy, how can some insects - even within the same species and population - be dormant in very warm environments or show prolonged dormancy for many successive years? In this Commentary, we discuss major assumptions regarding dormancy energetics and outline cases where insects appear to align with our assumptions and where they do not. We then highlight several research directions that could help link organismal energy use with landscape-level changes. Overall, the optimal energetic strategy during dormancy might not be to simply minimize metabolic rate, but instead to maintain a level that matches the demands of the specific life-history strategy. Given the influence of temperature on energy use rates of insects in winter, understanding dormancy energetic strategies is critical in order to determine the potential impacts of climate change on insects in seasonal environments.
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Affiliation(s)
- Kevin T Roberts
- Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Andre Szejner-Sigal
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Philipp Lehmann
- Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden
- Department of Animal Physiology, Zoological Institute and Museum, University of Greifswald, 17489 Greifswald, Germany
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13
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Wacker CB, Geiser F. The Rate of Cooling during Torpor Entry Drives Torpor Patterns in a Small Marsupial. Physiol Biochem Zool 2023; 96:393-404. [PMID: 38237188 DOI: 10.1086/727975] [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: 01/23/2024]
Abstract
AbstractTo maximize energy savings, entry into torpor should involve a fast reduction of metabolic rate and body temperature (Tb); that is, animals should thermoconform. However, animals often defend against the decrease in Tb via a temporary increase in thermoregulatory heat production, slowing the cooling process. We investigated how thermoregulating or thermoconforming during torpor entry affects temporal and thermoenergetic aspects in relation to body mass and age in juvenile and adult fat-tailed dunnarts (Sminthopsis crassicaudata; Marsupialia: Dasyuridae). During torpor entry, juvenile thermoconformers cooled twice as fast as and used less energy during cooling than juvenile thermoregulators. While both juvenile and adult thermoconformers had a lower minimum Tb, a lower torpor metabolic rate, and longer torpor bouts than thermoregulators, these differences were more pronounced in the juveniles. Rewarming from torpor took approximately twice as long for juvenile thermoconformers, and the costs of rewarming were greater. To determine the difference in average daily metabolic rate between thermoconformers and thermoregulators independent of body mass, we compared juveniles of a similar size (∼13 g) and similarly sized adults (∼17 g). The average daily metabolic rate was 7% (juveniles) and 17% (adults) less in thermoconformers than in thermoregulators, even though thermoconformers were active for longer. Our data suggest that thermoconforming during torpor entry provides an energetic advantage for both juvenile and adult dunnarts and may aid growth for juveniles. While thermoregulation during torpor entry is more costly, it still saves energy, and the higher Tb permits greater alertness and mobility and reduces the energetic cost of endogenous rewarming.
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Power ML, Ransome RD, Riquier S, Romaine L, Jones G, Teeling EC. Hibernation telomere dynamics in a shifting climate: insights from wild greater horseshoe bats. Proc Biol Sci 2023; 290:20231589. [PMID: 37817598 PMCID: PMC10565397 DOI: 10.1098/rspb.2023.1589] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 09/10/2023] [Indexed: 10/12/2023] Open
Abstract
Hibernation is linked with various hypotheses to explain the extended lifespan of hibernating mammals compared with their non-hibernating counterparts. Studies on telomeres, markers of ageing and somatic maintenance, suggest telomere shortening slows during hibernation, and lengthening may reflect self-maintenance with favourable conditions. Bats in temperate zones adjust body temperatures during winter torpor to conserve energy and exploit mild conditions for foraging. Climate change may impact the hibernation cycle of bats, but more research is needed regarding the role of telomeres in understanding their response to a changing climate. Here, relative telomere length (rTL) was measured in the long-lived greater horseshoe bat Rhinolophus ferrumequinum (n = 223 individuals) over three winters, considering climatic conditions. Cross-sectional analyses revealed between-individual variation in rTL with a strong year effect, likely linked to varying weather conditions and foraging success. Additionally, within-individual increases of rTL occurred in 51% of consecutive measurements, with evidence of increasing telomerase expression during hibernation in this species. These findings highlight the beneficial effects of hibernation on telomeres and potential consequences of changing climatic conditions for long-lived temperate bats. Understanding the interplay between hibernation, telomeres, and climate can provide insights into the adaptive capacity and survival of bat populations facing environmental challenges.
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Affiliation(s)
- Megan L Power
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Dublin 4, Republic of Ireland
| | - Roger D Ransome
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Sébastien Riquier
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Dublin 4, Republic of Ireland
| | - Luke Romaine
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Gareth Jones
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Emma C Teeling
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Dublin 4, Republic of Ireland
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15
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Fjelldal MA, Muller AS, Ratikainen II, Stawski C, Wright J. The small-bat-in-summer paradigm: Energetics and adaptive behavioural routines of bats investigated through a stochastic dynamic model. J Anim Ecol 2023; 92:2078-2093. [PMID: 37661664 DOI: 10.1111/1365-2656.13999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 08/16/2023] [Indexed: 09/05/2023]
Abstract
Strong seasonality at high latitudes represents a major challenge for many endotherms as they must balance survival and reproduction in an environment that varies widely in food availability and temperature. To avoid energetic mismatches caused by limited foraging time and stochastic weather conditions, bats employ the energy-saving state of torpor during summer to save accumulated energy reserves. However, at high-latitude small-bats-in-summer face a particular challenge: as nocturnal foragers, they rely on the darkness at night to avoid predators and/or interspecific competition, but live in an environment with short, light summer nights, and even a lack of true night at the northernmost distributions of some bat species. To predict optimal behaviour in relation to latitudinal variation in diurnal cycles, we constructed a stochastic dynamic programming model of bats living at high latitudes. Using a stochastic dynamic programming framework with values that are representative for our study system, we show that individual energetic reserves are a strong driver of daytime use of torpor and night-time foraging behaviour alike, with these linked effects being both temperature- and photoperiod-dependent. We further used the model to predict survival probabilities at five locations across a latitudinal gradient (60.1° N to 70.9° N), finding that combinations of photoperiod and temperature conditions limited population distributions in the model. To verify our model results, we compared predictions for optimal decisions with our own empirical data collected on northern bats (Eptesicus nilssonii) from two latitudes in Norway. The similarities between our predictions and observations provide strong evidence that this model framework incorporates the most important drivers of diurnal decision-making in bat physiology and behaviour. Comparing empirical data and model predictions also revealed that bats facing lighter night conditions further north restrict their mass gain, which strengthens the hypothesis that predation threat is a main driver of bat nocturnality. Our model findings regarding state-dependent decisions in bats should contribute to the understanding of how bats cope with the summer challenges at high latitudes.
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Affiliation(s)
- Mari Aas Fjelldal
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Amandine Sophie Muller
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Irja Ida Ratikainen
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- School of Science, Technology and Engineering, University of the Sunshine Coast (USC), Maroochydore DC, Queensland, Australia
| | - Jonathan Wright
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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Tamian A, Edwards PD, Neuhaus P, Boonstra R, Ruckstuhl AN, Emmanuel P, Pardonnet S, Palme R, Filippi D, Dobson FS, Saraux C, Viblanc VA. Weathering the storm: Decreased activity and glucocorticoid levels in response to inclement weather in breeding Columbian ground squirrels. Horm Behav 2023; 155:105426. [PMID: 37716083 DOI: 10.1016/j.yhbeh.2023.105426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/22/2023] [Accepted: 08/31/2023] [Indexed: 09/18/2023]
Abstract
Inclement weather can rapidly modify the thermal conditions experienced by animals, inducing changes in their behavior, body condition, and stress physiology, and affecting their survival and breeding success. For animals living in variable environments, the extent to which they have adapted to cope with inclement weather is not established, especially for hibernating species with a short active season that are constrained temporally to breed and store energy for subsequent hibernation. We examined behavioral (foraging activity) and physiological (body mass and fecal cortisol metabolites) responses of Columbian ground squirrels (Urocitellus columbianus), small hibernating rodents inhabiting open meadows in Rocky Mountains, to 3 events of inclement weather (two snow storms in May 2021 and May 2022, one heavy rainfall in June 2022). We found that individuals adapted to inclement weather conditions by (1) reducing above-ground activity, including foraging, (2) decreasing the mobilization of stored resources as indicated by a decrease in the activity of the hypothalamo-pituitary-adrenal (HPA) axis and lower fecal cortisol metabolites in the hours/days following periods of inclement weather; and (3) compensating through increased foraging and more local activity when favorable conditions resumed. As a result, body mass and growth did not decrease following short periods of inclement weather. Columbian ground squirrels were well-adapted to short periods of inclement weather, coping via modifications of their behavior and the activity of the HPA axis.
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Affiliation(s)
- Anouch Tamian
- Institut Pluridisciplinaire Hubert Curien, CNRS, Département Ecologie, Physiologie et Ethologie, 23 Rue du Loess, 67037 Strasbourg, France.
| | - Phoebe D Edwards
- Department of Biological Sciences, University of Toronto Scarborough, ON M1C 1A4, Canada
| | - Peter Neuhaus
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, ON M1C 1A4, Canada
| | | | - Patience Emmanuel
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Sylvia Pardonnet
- Institut Pluridisciplinaire Hubert Curien, CNRS, Département Ecologie, Physiologie et Ethologie, 23 Rue du Loess, 67037 Strasbourg, France
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Dominique Filippi
- Sextant Technology Ltd., 131 Tutaenui Rd, RD2, 4788 Marton, New Zealand
| | - F Stephen Dobson
- Institut Pluridisciplinaire Hubert Curien, CNRS, Département Ecologie, Physiologie et Ethologie, 23 Rue du Loess, 67037 Strasbourg, France; Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Claire Saraux
- Institut Pluridisciplinaire Hubert Curien, CNRS, Département Ecologie, Physiologie et Ethologie, 23 Rue du Loess, 67037 Strasbourg, France
| | - Vincent A Viblanc
- Institut Pluridisciplinaire Hubert Curien, CNRS, Département Ecologie, Physiologie et Ethologie, 23 Rue du Loess, 67037 Strasbourg, France
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17
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Emser SV, Spielvogel CP, Millesi E, Steinborn R. Mitochondrial polymorphism m.3017C>T of SHLP6 relates to heterothermy. Front Physiol 2023; 14:1207620. [PMID: 37675281 PMCID: PMC10478271 DOI: 10.3389/fphys.2023.1207620] [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: 04/17/2023] [Accepted: 07/31/2023] [Indexed: 09/08/2023] Open
Abstract
Heterothermic thermoregulation requires intricate regulation of metabolic rate and activation of pro-survival factors. Eliciting these responses and coordinating the necessary energy shifts likely involves retrograde signalling by mitochondrial-derived peptides (MDPs). Members of the group were suggested before to play a role in heterothermic physiology, a key component of hibernation and daily torpor. Here we studied the mitochondrial single-nucleotide polymorphism (SNP) m.3017C>T that resides in the evolutionarily conserved gene MT-SHLP6. The substitution occurring in several mammalian orders causes truncation of SHLP6 peptide size from twenty to nine amino acids. Public mass spectrometric (MS) data of human SHLP6 indicated a canonical size of 20 amino acids, but not the use of alternative translation initiation codons that would expand the peptide. The shorter isoform of SHLP6 was found in heterothermic rodents at higher frequency compared to homeothermic rodents (p < 0.001). In heterothermic mammals it was associated with lower minimal body temperature (T b, p < 0.001). In the thirteen-lined ground squirrel, brown adipose tissue-a key organ required for hibernation, showed dynamic changes of the steady-state transcript level of mt-Shlp6. The level was significantly higher before hibernation and during interbout arousal and lower during torpor and after hibernation. Our finding argues to further explore the mode of action of SHLP6 size isoforms with respect to mammalian thermoregulation and possibly mitochondrial retrograde signalling.
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Affiliation(s)
- Sarah V. Emser
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria
- Genomics Core Facility, VetCore, University of Veterinary Medicine, Vienna, Austria
| | - Clemens P. Spielvogel
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Eva Millesi
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria
| | - Ralf Steinborn
- Genomics Core Facility, VetCore, University of Veterinary Medicine, Vienna, Austria
- Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
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18
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Kamata T, Yamada S, Sekijima T. Differential AMPK-mediated metabolic regulation observed in hibernation-style polymorphisms in Siberian chipmunks. Front Physiol 2023; 14:1220058. [PMID: 37664438 PMCID: PMC10468594 DOI: 10.3389/fphys.2023.1220058] [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: 05/10/2023] [Accepted: 08/07/2023] [Indexed: 09/05/2023] Open
Abstract
Hibernation is a unique physiological phenomenon allowing extreme hypothermia in endothermic mammals. Hypometabolism and hypothermia tolerance in hibernating animals have been investigated with particular interest; recently, studies of cultured cells and manipulation of the nervous system have made it possible to reproduce physiological states related to hypothermia induction. However, much remains unknown about the periodic regulation of hibernation. In particular, the physiological mechanisms facilitating the switch from an active state to a hibernation period, including behavioral changes and the acquisition of hypothermia tolerance remain to be elucidated. AMPK is a protein known to play a central role not only in feeding behavior but also in metabolic regulation in response to starvation. Our previous research has revealed that chipmunks activate AMPK in the brain during hibernation. However, whether AMPK is activated during winter in non-hibernating animals is unknown. Previous comparative studies between hibernating and non-hibernating animals have often been conducted between different species, consequently it has been impossible to account for the effects of phylogenetic differences. Our long-term monitoring of siberian chipmunks, has revealed intraspecific variation between those individuals that hibernate annually and those that never become hypothermic. Apparent differences were found between hibernating and non-hibernating types with seasonal changes in lifespan and blood HP levels. By comparing seasonal changes in AMPK activity between these polymorphisms, we clarified the relationship between hibernation and AMPK regulation. In hibernating types, phosphorylation of p-AMPK and p-ACC was enhanced throughout the brain during hibernation, indicating that AMPK-mediated metabolic regulation is activated. In non-hibernating types, AMPK and ACC were not seasonally activated. In addition, AMPK activation in the hypothalamus had already begun during high Tb before hibernation. Changes in AMPK activity in the brain during hibernation may be driven by circannual rhythms, suggesting a hibernation-regulatory mechanism involving AMPK activation independent of Tb. The differences in brain AMPK regulation between hibernators and non-hibernators revealed in this study were based on a single species thus did not involve phylogenetic differences, thereby supporting the importance of brain temperature-independent AMPK activation in regulating seasonal metabolism in hibernating animals.
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Affiliation(s)
- Taito Kamata
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
- Faculty of Agriculture, Niigata University, Niigata, Japan
| | - Shintaro Yamada
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
- Institute of Biomedical Science, Kansai Medical University, Osaka, Japan
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Lopez LK, Gil MA, Crowley PH, Trimmer PC, Munson A, Ligocki IY, Michelangeli M, Sih A. Integrating animal behaviour into research on multiple environmental stressors: a conceptual framework. Biol Rev Camb Philos Soc 2023; 98:1345-1364. [PMID: 37004993 DOI: 10.1111/brv.12956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 03/18/2023] [Accepted: 03/24/2023] [Indexed: 04/04/2023]
Abstract
While a large body of research has focused on the physiological effects of multiple environmental stressors, how behavioural and life-history plasticity mediate multiple-stressor effects remains underexplored. Behavioural plasticity can not only drive organism-level responses to stressors directly but can also mediate physiological responses. Here, we provide a conceptual framework incorporating four fundamental trade-offs that explicitly link animal behaviour to life-history-based pathways for energy allocation, shaping the impact of multiple stressors on fitness. We first address how small-scale behavioural changes can either mediate or drive conflicts between the effects of multiple stressors and alternative physiological responses. We then discuss how animal behaviour gives rise to three additional understudied and interrelated trade-offs: balancing the benefits and risks of obtaining the energy needed to cope with stressors, allocation of energy between life-history traits and stressor responses, and larger-scale escape from stressors in space or time via large-scale movement or dormancy. Finally, we outline how these trade-offs interactively affect fitness and qualitative ecological outcomes resulting from multiple stressors. Our framework suggests that explicitly considering animal behaviour should enrich our mechanistic understanding of stressor effects, help explain extensive context dependence observed in these effects, and highlight promising avenues for future empirical and theoretical research.
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Affiliation(s)
- Laura K Lopez
- Department of Environmental Science & Policy, University of California, 2132 Wickson Hall, One Shields Avenue, Davis, CA, 95616, USA
- National Centre for Immunisation Research and Surveillance, Kids Research, Sydney Children's Hospitals Network, Corner Hawkesbury Road & Hainsworth Street, Westmead, New South Wales, 2145, Australia
| | - Michael A Gil
- Department of Environmental Science & Policy, University of California, 2132 Wickson Hall, One Shields Avenue, Davis, CA, 95616, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122/Campus Box 334, Boulder, CO, 80309-0334, USA
| | - Philip H Crowley
- Department of Biology, University of Kentucky, 195 Huguelet Drive, 101 Thomas Hunt Morgan Building, Lexington, KY, 40506-0225, USA
| | - Pete C Trimmer
- Department of Environmental Science & Policy, University of California, 2132 Wickson Hall, One Shields Avenue, Davis, CA, 95616, USA
- Department of Psychology, University of Warwick, University Road, Coventry, CV4 7AL, UK
| | - Amelia Munson
- Department of Environmental Science & Policy, University of California, 2132 Wickson Hall, One Shields Avenue, Davis, CA, 95616, USA
| | - Isaac Y Ligocki
- Department of Biology, Millersville University of Pennsylvania, Roddy Science Hall, PO Box 1002, Millersville, PA, 17551, USA
- Department of Evolution, Ecology, and Organismal Biology, Ohio State University, 318 W. 12th Avenue, Columbus, OH, 43210, USA
| | - Marcus Michelangeli
- Department of Environmental Science & Policy, University of California, 2132 Wickson Hall, One Shields Avenue, Davis, CA, 95616, USA
- Department of Wildlife, Fish & Environmental Studies, Swedish University of Agricultural Sciences, Skogsmarksgränd, Umeå, SE-907 36, Sweden
| | - Andrew Sih
- Department of Environmental Science & Policy, University of California, 2132 Wickson Hall, One Shields Avenue, Davis, CA, 95616, USA
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Brown L, Zedrosser A, Arnemo JM, Fuchs B, Kindberg J, Pelletier F. Landscape of fear or landscape of food? Moose hunting triggers an antipredator response in brown bears. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2840. [PMID: 36912774 PMCID: PMC10909462 DOI: 10.1002/eap.2840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/13/2023] [Accepted: 02/10/2023] [Indexed: 06/02/2023]
Abstract
Hunters can affect the behavior of wildlife by inducing a landscape of fear, selecting individuals with specific traits, or altering resource availability across the landscape. Most research investigating the influence of hunting on wildlife resource selection has focused on target species and less attention has been devoted to nontarget species, such as scavengers that can be both attracted or repelled by hunting activities. We used resource selection functions to identify areas where hunters were most likely to kill moose (Alces alces) in south-central Sweden during the fall. Then, we used step-selection functions to determine whether female brown bears (Ursus arctos) selected or avoided these areas and specific resources during the moose hunting season. We found that, during both day and nighttime, female brown bears avoided areas where hunters were more likely to kill moose. We found evidence that resource selection by brown bears varied substantially during the fall and that some behavioral changes were consistent with disturbance associated with moose hunters. Brown bears were more likely to select concealed locations in young (i.e., regenerating) and coniferous forests and areas further away from roads during the moose hunting season. Our results suggest that brown bears react to both spatial and temporal variations in apparent risk during the fall: moose hunters create a landscape of fear and trigger an antipredator response in a large carnivore even if bears are not specifically targeted during the moose hunting season. Such antipredator responses might lead to indirect habitat loss and lower foraging efficiency and the resulting consequences should be considered when planning hunting seasons.
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Affiliation(s)
- Ludovick Brown
- Département de biologieUniversité de SherbrookeSherbrookeCanada
| | - Andreas Zedrosser
- Department of Natural Sciences and Environmental HealthUniversity of South‐Eastern NorwayBø in TelemarkNorway
- Institute for Wildlife Biology and Game ManagementUniversity for Natural Resources and Life SciencesViennaAustria
| | - Jon M. Arnemo
- Department of Forestry and Wildlife ManagementInland Norway University of Applied SciencesKoppangNorway
- Department of Wildlife, Fish and Environmental StudiesSwedish University of Agricultural SciencesUmeåSweden
| | - Boris Fuchs
- Department of Forestry and Wildlife ManagementInland Norway University of Applied SciencesKoppangNorway
| | - Jonas Kindberg
- Department of Wildlife, Fish and Environmental StudiesSwedish University of Agricultural SciencesUmeåSweden
- Norwegian Institute for Nature ResearchTrondheimNorway
| | - Fanie Pelletier
- Département de biologieUniversité de SherbrookeSherbrookeCanada
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Giroud S, Ragger MT, Baille A, Hoelzl F, Smith S, Nowack J, Ruf T. Food availability positively affects the survival and somatic maintenance of hibernating garden dormice (Eliomys quercinus). Front Zool 2023; 20:19. [PMID: 37226260 PMCID: PMC10207780 DOI: 10.1186/s12983-023-00498-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/15/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Torpor is an energy saving strategy achieved by substantial reductions of metabolic rate and body temperature that enables animals to survive periods of low resource availability. During hibernation (multiday torpor), the frequency of periodic rewarming-characterised by high levels of oxidative stress-is associated with shortening of telomeres, a marker of somatic maintenance. OBJECTIVES In this study, we determined the impact of ambient temperature on feeding behaviour and telomere dynamics in hibernating garden dormice (Eliomys quercinus) over winter. This obligate hibernator prepares for hibernation by accumulating fat stores but can also feed during hibernation. METHODOLOGY Food intake, torpor pattern, changes in telomere length, and body mass change were assessed in animals housed at experimentally controlled temperatures of either 14 °C (i.e., a mild winter) or 3 °C (i.e., a cold winter) over 6 months. RESULTS When hibernating at 14 °C, dormice experienced 1.7-fold more frequent and 2.4-fold longer inter-bout euthermia, and spent significantly less time torpid, compared to animals hibernating at 3 °C. Higher food intake enabled individuals to compensate for increased energetic costs when hibernating at milder temperatures (14 °C vs. 3 °C), to buffer body mass loss and thus increase winter survival. Interestingly, we observed a significant increase of telomere length over the entire hibernation period, irrespective of temperature treatment. CONCLUSION We conclude that higher temperatures during winter, if associated with sufficient food availability, can have a positive effect on the individual's energy balance and somatic maintenance. These results suggest that winter food availability might be a crucial determinant for the survival of the garden dormouse in the context of ever-increasing environmental temperatures.
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Affiliation(s)
- Sylvain Giroud
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Savoyenstraße 1, 1160, Vienna, Austria.
| | - Marie-Therese Ragger
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Savoyenstraße 1, 1160, Vienna, Austria
| | - Amélie Baille
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Savoyenstraße 1, 1160, Vienna, Austria
| | - Franz Hoelzl
- Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Steve Smith
- Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Julia Nowack
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Savoyenstraße 1, 1160, Vienna, Austria
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
| | - Thomas Ruf
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Savoyenstraße 1, 1160, Vienna, Austria
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22
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Kissmann AK, Rosenau F, Herwig A, Diedrich V. Short Photoperiod-Dependent Enrichment of Akkermansia spec. as the Major Change in the Intestinal Microbiome of Djungarian Hamsters (Phodopus sungorus). Int J Mol Sci 2023; 24:ijms24076605. [PMID: 37047584 PMCID: PMC10095574 DOI: 10.3390/ijms24076605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/27/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
The Djungarian hamster (Phodopus sungorus) is a prominent model organism for seasonal acclimatization, showing drastic whole-body physiological adjustments to an energetically challenging environment, which are considered to also involve the gut microbiome. Fecal samples of hamsters in long photoperiod and again after twelve weeks in short photoperiod were analyzed by 16S-rRNA sequencing to evaluate seasonal changes in the respective gut microbiomes. In both photoperiods, the overall composition was stable in the major superordinate phyla of the microbiota, with distinct and delicate changes of abundance in phyla representing each <1% of all. Elusimicrobia, Tenericutes, and Verrucomicrobia were exclusively present in short photoperiod hamsters. In contrast to Elusimicrobium and Aneroplasma as representatives of Elusimicrobia and Tenericutes, Akkermansia muciniphila is a prominent gut microbiome inhabitant well described as important in the health context of animals and humans, including neurodegenerative diseases and obesity. Since diet was not changed, Akkermansia enrichment appears to be a direct consequence of short photoperiod acclimation. Future research will investigate whether the Djungarian hamster intestinal microbiome is responsible for or responsive to seasonal acclimation, focusing on probiotic supplementation.
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Affiliation(s)
- Ann-Kathrin Kissmann
- Institute for Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Frank Rosenau
- Institute for Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Annika Herwig
- Institute of Neurobiology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Victoria Diedrich
- Institute of Neurobiology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Rossi AJ, Klinger RC, Hellwig EC, Van Vuren DH. Niches of three sympatric montane ground‐dwelling squirrels: Relative importance of climate, topography, and landcover. Ecol Evol 2023; 13:e9949. [PMID: 37013103 PMCID: PMC10065979 DOI: 10.1002/ece3.9949] [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: 01/10/2023] [Revised: 03/07/2023] [Accepted: 03/12/2023] [Indexed: 04/03/2023] Open
Abstract
Species with different ecological niches will likely exhibit distinct responses to a changing environment. Differences in the magnitude of niche specialization may also indicate which species may be more vulnerable to environmental change, as many life‐history characteristics are known to affect climate change vulnerability. We characterized the niche space of three sympatric high‐elevation ground‐dwelling squirrels, yellow‐bellied marmot (Marmota flaviventer), Belding's ground squirrel (Urocitellus beldingi), and golden‐mantled ground squirrel (Callospermophilus lateralis), in the alpine and upper subalpine regions of the Sierra Nevada in California. We used 5879 observations of individual squirrels, collected from 4 years (2009–2012) of transect survey data, to quantify which ecogeographical variable types (climate, topography, or landcover) were most important in defining the niche of each species. We conducted Ecological Niche Factor Analysis to quantify the niche and generate indices of “marginality” (magnitude of selection) and “specialization” (narrowness of niche space). All three species demonstrated differential use of niche space when compared to the available niche space. Moreover, the relative importance of the variables shaping the niche differed among these species. For example, the presence of meadows was important in defining the niche for U. beldingi and M. flaviventer, but the presence of conifers was important to C. lateralis. Precipitation was important in defining the niche for all three species, positively so for U. beldingi, and negatively for the other two species. The niche breadth of these three species was also positively associated with geographic range size. Mammals in high‐elevation mountain systems often are perceived as vulnerable to climate shifts, but our results underscore the importance of also including non‐climate‐based factors in defining the niche. The overall magnitude of niche selection for all three species was driven by a combination of topographic, climatic, and landcover factors; thus, efforts to forecast areas where these species can persist in the future need to evaluate from more than just a climatic perspective.
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Affiliation(s)
- Aviva J. Rossi
- Department of Wildlife, Fish, & Conservation BiologyUniversity of California, DavisOne Shields AvenueDavisCalifornia95616USA
| | - Robert C. Klinger
- Western Ecological Research CenterU.S. Geological Survey2761 Glenbrook WayBishopCalifornia93514USA
| | - Elise C. Hellwig
- Department of Wildlife, Fish, & Conservation BiologyUniversity of California, DavisOne Shields AvenueDavisCalifornia95616USA
| | - Dirk H. Van Vuren
- Department of Wildlife, Fish, & Conservation BiologyUniversity of California, DavisOne Shields AvenueDavisCalifornia95616USA
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24
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Langwig KE, Kilpatrick AM, Kailing MJ, Laggan NA, White JP, Kaarakka HM, Redell JA, DePue JE, Parise KL, Foster JT, Hoyt JR. Shifting effects of host physiological condition following pathogen establishment. Biol Lett 2023; 19:20220574. [PMID: 36855852 PMCID: PMC9975657 DOI: 10.1098/rsbl.2022.0574] [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] [Indexed: 03/02/2023] Open
Abstract
Understanding host persistence with emerging pathogens is essential for conserving populations. Hosts may initially survive pathogen invasions through pre-adaptive mechanisms. However, whether pre-adaptive traits are directionally selected to increase in frequency depends on the heritability and environmental dependence of the trait and the costs of trait maintenance. Body condition is likely an important pre-adaptive mechanism aiding in host survival, although can be seasonally variable in wildlife hosts. We used data collected over 7 years on bat body mass, infection and survival to determine the role of host body condition during the invasion and establishment of the emerging disease, white-nose syndrome. We found that when the pathogen first invaded, bats with higher body mass were more likely to survive, but this effect dissipated following the initial epizootic. We also found that heavier bats lost more weight overwinter, but fat loss depended on infection severity. Lastly, we found mixed support that bat mass increased in the population after pathogen arrival; high annual plasticity in individual bat masses may have reduced the potential for directional selection. Overall, our results suggest that some factors that contribute to host survival during pathogen invasion may diminish over time and are potentially replaced by other host adaptations.
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Affiliation(s)
- Kate E Langwig
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, VA 24061, USA
| | - A Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA
| | - Macy J Kailing
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, VA 24061, USA
| | - Nichole A Laggan
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, VA 24061, USA
| | - J Paul White
- Wisconsin Department of Natural Resources, Madison, WI 53707, USA
| | | | | | - John E DePue
- Michigan Department of Natural Resources, Baraga, MI 49908, USA
| | - Katy L Parise
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Jeffrey T Foster
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Joseph R Hoyt
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, VA 24061, USA
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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
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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
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Energy expenditure and body composition in a hibernator, the alpine marmot. J Comp Physiol B 2023; 193:135-143. [PMID: 36335482 PMCID: PMC9852207 DOI: 10.1007/s00360-022-01466-1] [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: 08/10/2022] [Revised: 10/11/2022] [Accepted: 10/23/2022] [Indexed: 11/08/2022]
Abstract
Visceral organs and tissues of 89 free-living alpine marmots (Marmota marmota) shot during a population control program in Switzerland, were collected. Between emergence from hibernation in April to July, the gastrointestinal tract (stomach to colon) gained 51% of mass and the liver mass increased by 24%. At the same time, the basal metabolic rate (BMR), determined with a portable oxygen analyzer, increased by 18%. The organ masses of the digestive system (stomach, small intestine, caecum, large intestine) were all significantly correlated with BMR. Interestingly, the mass of abdominal white adipose tissue (WAT) and of the remaining carcass (mainly skin and bones) were also significantly correlated with BMR. These results indicate that the gastrointestinal tract and organs involved in digestive function are metabolically expensive. They also show that it is costly to maintain even tissues with low metabolic rate such as WAT, especially if they are large. Heart and kidneys and especially brain and lungs did not explain a large proportion of the variance in BMR. Marmots increased the uptake of fat prior to hibernation, both by selective feeding and enhanced gastrointestinal capacity. Large fat reserves enable marmots to hibernate without food intake and to reproduce in spring, but at the cost of an elevated BMR. We predict that climate changes that disturb energy accumulation in summer, increase energy expenditure in winter, or delay the emergence from hibernation in spring, such as the occurrence of storms with increasing frequency, will increase mortality in alpine marmots.
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Determining the different phases of torpor from skin- or body temperature data in heterotherms. J Therm Biol 2023; 111:103396. [PMID: 36585072 DOI: 10.1016/j.jtherbio.2022.103396] [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: 06/08/2022] [Revised: 10/28/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
Technological innovations have made heat-sensitive data-loggers smaller, more efficient and less expensive, which has led to a growing body of literature that measures the skin- or body temperatures of small animals in their natural environments. Studies of this type on heterothermic endotherms have prompted much debate regarding how to best define 'torpor' expressions from skin- or body temperature data alone. We propose a new quantitative method for defining torpor 'entries', 'arousals' and 'stable torpor periods' whilst comparing the results to 'torpor bout' durations identified using only the torpor cut-off method. By decomposing a torpor bout into 'entries', 'stable torpor periods', and 'active arousals', we avoid biases introduced by using strict threshold temperature values for the onset of torpor, thereby allowing better insight into individual use of torpor. We present our method as an easy-to-use function written in R-code, offering an un-biased and consistent methodology to be applied on skin- or body temperature measurements across datasets and research groups. When testing the function on a large dataset of skin temperature data collected on three bat species in Norway (Plecotus auritus: Nind = 39; Eptesicus nilssonii: Nind = 11; Myotis brandtii: Nind = 10), we identified 461 complete torpor bouts across species. More than 40% of the torpor bouts (Nbouts = 192) did not contain stable torpor periods, because the bats aroused before they had reached a stable skin temperature level. Furthermore, only considering 'torpid' and 'euthermic' temperature values by applying strict cut-off thresholds led to potentially large underestimations of torpor bout durations compared to our quantitative determination of the onset and termination of each torpor bout. We highlight the importance of differentiating between torpor phases, especially for active arousals that can be very energetically expensive and may alter our evaluation of the actual energetic savings gained by an individual employing torpor.
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Combe FJ, Juškaitis R, Trout RC, Bird S, Ellis JS, Norrey J, Al‐Fulaij N, White I, Harris WE. Density and climate effects on age‐specific survival and population growth: consequences for hibernating mammals. Anim Conserv 2022. [DOI: 10.1111/acv.12843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- F. J. Combe
- Division of Biology and Conservation Ecology, School of Science and the Environment Manchester Metropolitan University Manchester UK
- Division of Biology Kansas State University Manhattan KS USA
| | | | | | - S. Bird
- North of England Zoological Society Chester UK
| | - J. S. Ellis
- School of Biological and Marine Sciences University of Plymouth Plymouth UK
| | - J. Norrey
- Division of Biology and Conservation Ecology, School of Science and the Environment Manchester Metropolitan University Manchester UK
| | | | - I. White
- People's Trust for Endangered Species London UK
| | - W. E. Harris
- Agriculture and Environment Sciences Department Harper Adams University Newport UK
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30
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López JM, Carballeira P, Pozo J, León-Espinosa G, Muñoz A. Hypothalamic orexinergic neuron changes during the hibernation of the Syrian hamster. Front Neuroanat 2022; 16:993421. [PMID: 36157325 PMCID: PMC9501701 DOI: 10.3389/fnana.2022.993421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/09/2022] [Indexed: 11/23/2022] Open
Abstract
Hibernation in small mammals is a highly regulated process with periods of torpor involving drops in body temperature and metabolic rate, as well as a general decrease in neural activity, all of which proceed alongside complex brain adaptive changes that appear to protect the brain from extreme hypoxia and low temperatures. All these changes are rapidly reversed, with no apparent brain damage occurring, during the short periods of arousal, interspersed during torpor—characterized by transitory and partial rewarming and activity, including sleep activation, and feeding in some species. The orexins are neuropeptides synthesized in hypothalamic neurons that project to multiple brain regions and are known to participate in the regulation of a variety of processes including feeding behavior, the sleep-wake cycle, and autonomic functions such as brown adipose tissue thermogenesis. Using multiple immunohistochemical techniques and quantitative analysis, we have characterized the orexinergic system in the brain of the Syrian hamster—a facultative hibernator. Our results revealed that orexinergic neurons in this species consisted of a neuronal population restricted to the lateral hypothalamic area, whereas orexinergic fibers distribute throughout the rostrocaudal extent of the brain, particularly innervating catecholaminergic and serotonergic neuronal populations. We characterized the changes of orexinergic cells in the different phases of hibernation based on the intensity of immunostaining for the neuronal activity marker C-Fos and orexin A (OXA). During torpor, we found an increase in C-Fos immunostaining intensity in orexinergic neurons, accompanied by a decrease in OXA immunostaining. These changes were accompanied by a volume reduction and a fragmentation of the Golgi apparatus (GA) as well as a decrease in the colocalization of OXA and the GA marker GM-130. Importantly, during arousal, C-Fos and OXA expression in orexinergic neurons was highest and the structural appearance and the volume of the GA along with the colocalization of OXA/GM-130 reverted to euthermic levels. We discuss the involvement of orexinergic cells in the regulation of mammalian hibernation and, in particular, the possibility that the high activation of orexinergic cells during the arousal stage guides the rewarming as well as the feeding and sleep behaviors characteristic of this phase.
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Affiliation(s)
- Jesús M. López
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Paula Carballeira
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Javier Pozo
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Gonzalo León-Espinosa
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-Centro de Estudios Universitarios (CEU), Madrid, Spain
| | - Alberto Muñoz
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica (CTB), Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- *Correspondence: Alberto Muñoz,
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31
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Balzer EW, Grottoli AD, Burns LE, Broders HG. Active season body mass patterns of little brown and northern myotis bats. Ecol Evol 2022. [DOI: 10.1002/ece3.9230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Evan W. Balzer
- Department of Biology University of Waterloo Waterloo Ontario Canada
| | - Adam D. Grottoli
- Department of Biology University of Waterloo Waterloo Ontario Canada
| | - Lynne E. Burns
- Environment and Climate Change Canada Edmonton Alberta Canada
| | - Hugh G. Broders
- Department of Biology University of Waterloo Waterloo Ontario Canada
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Zhou J, Wang M, Yi X. Alteration of Gut Microbiota of a Food-Storing Hibernator, Siberian Chipmunk Tamias sibiricus. MICROBIAL ECOLOGY 2022; 84:603-612. [PMID: 34562129 DOI: 10.1007/s00248-021-01877-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 09/17/2021] [Indexed: 06/13/2023]
Abstract
Hibernation represents a state of fasting because hibernators cease eating in the torpid periods. Therefore, food deprivation during hibernation is expected to modify the gut microbiota of host. However, there are few reports of gut microbiota in food-storing hibernators that feed during the interbout arousals. Here we collected fecal samples of Siberian chipmunk T. sibiricus to character and examine changes in the gut microbiota at various stages relative to hibernation: pre-hibernation, early-hibernation, mid-hibernation, late-hibernation, and post-hibernation. Compared to the pre-hibernation state, alpha-diversity of gut microbiota was significantly increased during the interbout arousal periods. In addition, beta-diversity of the fecal communities from pre-hibernation and interbout arousal periods grouped together, and post-hibernation gut microbiota resembled the counterpart at late-hibernation. Hibernation significantly decreased the relative abundance of Firmicutes but increased Bacteroidetes, reflecting a shift of microbiota toward taxa in favor of host-derived substrates. The increased abundance of Ruminococcaceae_UCG-014, Lactobacillus, and Christensenellaceae_R-7_group in gut microbiota may help the chipmunks reduce intestinal inflammation and then maintain healthy bowel during hibernation. KEGG pathway indicated that hibernation altered the metabolic function of gut microflora of T. sibiricus. Our study provides evidence that the gut microbiota of food-storing hibernators, despite feeding during the interbout arousals, shows similar response to hibernation that has well documented in fat-storing counterparts, suggesting the potential for a core gut microbiota during hibernation of mammals. Importantly, these results will broaden our understanding of the effects of hibernation on gut microbiota of mammal hibernators.
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Affiliation(s)
- Jing Zhou
- College of Life Sciences, Qufu Normal University, Qufu, 273165, China
| | - Minghui Wang
- College of Life Sciences, Qufu Normal University, Qufu, 273165, China
| | - Xianfeng Yi
- College of Life Sciences, Qufu Normal University, Qufu, 273165, China.
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Antonova EP, Belkin VV, Ilyukha VA, Khizhkin EA, Kalinina SN. Seasonal Changes in Body Mass and Activity of Digestive Enzymes in Eptesicus nilssonii (Mammalia: Chiroptera: Vespertilionidae) during Hibernation. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s002209302204010x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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34
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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.
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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.
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35
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Nichols RC, Cade DE, Kahane-Rapport S, Goldbogen J, Stimpert A, Nowacek D, Read AJ, Johnston DW, Friedlaender A. Intra-seasonal variation in feeding rates and diel foraging behaviour in a seasonally fasting mammal, the humpback whale. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211674. [PMID: 35814912 PMCID: PMC9257586 DOI: 10.1098/rsos.211674] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 06/13/2022] [Indexed: 06/01/2023]
Abstract
Antarctic humpback whales forage in summer, coincident with the seasonal abundance of their primary prey, the Antarctic krill. During the feeding season, humpback whales accumulate energy stores sufficient to fuel their fasting period lasting over six months. Previous animal movement modelling work (using area-restricted search as a proxy) suggests a hyperphagic period late in the feeding season, similar in timing to some terrestrial fasting mammals. However, no direct measures of seasonal foraging behaviour existed to corroborate this hypothesis. We attached high-resolution, motion-sensing biologging tags to 69 humpback whales along the Western Antarctic Peninsula throughout the feeding season from January to June to determine how foraging effort changes throughout the season. Our results did not support existing hypotheses: we found a significant reduction in foraging presence and feeding rates from the beginning to the end of the feeding season. During the early summer period, feeding occurred during all hours at high rates. As the season progressed, foraging occurred mostly at night and at lower rates. We provide novel information on seasonal changes in foraging of humpback whales and suggest that these animals, contrary to nearly all other animals that seasonally fast, exhibit high feeding rates soon after exiting the fasting period.
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Affiliation(s)
- Ross C. Nichols
- Institute of Marine Sciences, Long Marine Laboratory, University of California, Santa Cruz. 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - David E. Cade
- Department of Biology, Hopkins Marine Station, Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950, USA
| | - Shirel Kahane-Rapport
- Department of Biology, Hopkins Marine Station, Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950, USA
| | - Jeremy Goldbogen
- Department of Biology, Hopkins Marine Station, Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950, USA
| | - Alison Stimpert
- Moss Landing Marine Laboratories, San Jose State University, 8272 Moss Landing Road, Moss Landing, CA 95039, USA
| | - Douglas Nowacek
- Nicholas School of the Environment and Earth Sciences & Pratt School of Engineering, Duke University Marine Laboratory, 135 Duke Marine Lab Road, Beaufort, NC 28516, USA
| | - Andrew J. Read
- Nicholas School of the Environment and Earth Sciences, Duke University Marine Laboratory, 135 Duke Marine Lab Road, Beaufort, NC 28516, USA
| | - David W. Johnston
- Nicholas School of the Environment and Earth Sciences, Duke University Marine Laboratory, 135 Duke Marine Lab Road, Beaufort, NC 28516, USA
| | - Ari Friedlaender
- Institute of Marine Sciences, Long Marine Laboratory, University of California, Santa Cruz. 115 McAllister Way, Santa Cruz, CA 95060, USA
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Ruf T, Giroud S, Geiser F. Hypothesis and Theory: A Two-Process Model of Torpor-Arousal Regulation in Hibernators. Front Physiol 2022; 13:901270. [PMID: 35812322 PMCID: PMC9266152 DOI: 10.3389/fphys.2022.901270] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
Hibernating mammals drastically lower their metabolic rate (MR) and body temperature (Tb) for up to several weeks, but regularly rewarm and stay euthermic for brief periods. It has been hypothesized that the necessity for rewarming is due to the accumulation or depletion of metabolites, or the accrual of cellular damage that can be eliminated only in the euthermic state. Recent evidence for significant inverse relationships between the duration of torpor bouts (TBD) and MR in torpor strongly supports this hypothesis. We developed a new mathematical model that simulates hibernation patterns. The model involves an hourglass process H (Hibernation) representing the depletion/accumulation of a crucial enzyme/metabolite, and a threshold process Hthr. Arousal, modelled as a logistic process, is initiated once the exponentially declining process H reaches Hthr. We show that this model can predict several phenomena observed in hibernating mammals, namely the linear relationship between TMR and TBD, effects of ambient temperature on TBD, the modulation of torpor depth and duration within the hibernation season, (if process Hthr undergoes seasonal changes). The model does not need but allows for circadian cycles in the threshold T, which lead to arousals occurring predominantly at certain circadian phases, another phenomenon that has been observed in certain hibernators. It does not however, require circadian rhythms in Tb or MR during torpor. We argue that a two-process regulation of torpor-arousal cycles has several adaptive advantages, such as an easy adjustment of TBD to environmental conditions as well as to energy reserves and, for species that continue to forage, entrainment to the light-dark cycle.
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Affiliation(s)
- Thomas Ruf
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Vienna, Austria
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
- *Correspondence: Thomas Ruf,
| | - Sylvain Giroud
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
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Boonstra R, Gandhi N, Kraushaar A, Galbreath K. From Habitat to Hormones: Year-around territorial behavior in rock-dwelling but not in forest and grassland lagomorphs and the role of DHEA. Horm Behav 2022; 142:105179. [PMID: 35477059 DOI: 10.1016/j.yhbeh.2022.105179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/16/2022] [Accepted: 04/18/2022] [Indexed: 11/25/2022]
Abstract
Year-around defense of extremely patchy habitat may require hormones that drive territorial behavior, but have no other costly physiological effects. The American pika (Ochotona princeps), but not the snowshoe hare (Lepus americanus) nor the eastern cottontail rabbit (Sylvilagus floridanus), exhibits this behavior. The former engages in contest competition against all individuals independent of sex to protect its territory in highly fragmented patches on mountain talus slopes; the latter in scramble competition in more continuous forests, grasslands, and shrublands. The hormonal basis for this difference in lagomorphs is unknown. Dehydroepiandrosterone is a prohormone produced by the zona reticularis of the adrenal cortex. It has no effect on aggressive behavior until converted in the brain to estrogen. We assessed levels (DHEA-S plus DHEA) in all species collected in the wild. In nonbreeding pikas, levels were 256 times higher than in hares and 22 times higher than in rabbits. Within species, females and males had similar levels. The proportion of the adrenal cortex devoted to the zona reticularis was significantly larger in pikas than in hares or rabbits. Our evidence is consistent with the hypothesis that dehydroepiandrosterone drives this individual-based, year-around territoriality in pikas. We propose a definitive experiment to determine this and recommend comparative studies in central Asia where there is high diversity of pika species whose behavior ranges from individual-based territoriality to colonial. Thus, we speculate that the wild American pika has the adrenal-brain nexus for all seasons and is an excellent model to understand how habitat drives the hormonal control of spacing behavior.
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Affiliation(s)
- Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada.
| | - Nisha Gandhi
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Alec Kraushaar
- Department of Biology, Northern Michigan University, 1401 Presque Isle Ave, Marquette, MI 49855, USA
| | - Kurt Galbreath
- Department of Biology, Northern Michigan University, 1401 Presque Isle Ave, Marquette, MI 49855, USA
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38
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Przybylska-Piech AS, Jefimow M. Siberian hamsters nonresponding to short photoperiod use fasting-induced torpor. J Exp Biol 2022; 225:275527. [PMID: 35615921 DOI: 10.1242/jeb.244222] [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: 03/02/2022] [Accepted: 05/17/2022] [Indexed: 11/20/2022]
Abstract
Nonresponding Siberian hamsters Phodopus sungorus do not develop the winter phenotype with white fur, low body mass (mb) and spontaneous torpor use in response to short photoperiod. However, their thermoregulatory response to fasting remains unknown. We measured body temperature and mb of 12 nonresponders acclimated to short photoperiod and then to cold, and fasted four times for 24h. Four individuals used torpor and in total we recorded 19 torpor bouts, which were shallow, short, and occurred at night. Moreover fasting increased the heterothermy index in all hamsters. Low mb was not a prerequisite for torpor use and mb loss correlated with neither heterothermy index nor torpor use. This is the first evidence that individuals which do not develop the winter phenotype, can use torpor or increase body temperature variability to face unpredictable, adverse environmental conditions. Despite the lack of seasonal changes, thermoregulatory adjustments may increase winter survival probability of nonresponders.
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Affiliation(s)
- Anna S Przybylska-Piech
- Department of Vertebrate Zoology and Ecology; Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
| | - Małgorzata Jefimow
- Department of Animal Physiology and Neurobiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
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39
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Tamian A, Viblanc VA, Dobson FS, Neuhaus P, Hammer TL, Nesterova AP, Raveh S, Skibiel AL, Broussard D, Manno TG, Rajamani N, Saraux C. Integrating microclimatic variation in phenological responses to climate change: A 28‐year study in a hibernating mammal. Ecosphere 2022. [DOI: 10.1002/ecs2.4059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Anouch Tamian
- Département Ecologie, Physiologie et Ethologie Institut Pluridisciplinaire Hubert Curien, CNRS Strasbourg France
| | - Vincent A. Viblanc
- Département Ecologie, Physiologie et Ethologie Institut Pluridisciplinaire Hubert Curien, CNRS Strasbourg France
| | - F. Stephen Dobson
- Département Ecologie, Physiologie et Ethologie Institut Pluridisciplinaire Hubert Curien, CNRS Strasbourg France
- Department of Biological Sciences Auburn University Auburn Alabama USA
| | - Peter Neuhaus
- Department of Biological Sciences University of Calgary Calgary Canada
| | - Tracey L. Hammer
- Département Ecologie, Physiologie et Ethologie Institut Pluridisciplinaire Hubert Curien, CNRS Strasbourg France
- Department of Biological Sciences University of Calgary Calgary Canada
| | | | - Shirley Raveh
- Institute of Biodiversity, Animal Health and Comparative Medicine University of Glasgow Glasgow UK
| | - Amy L. Skibiel
- Department of Animal, Veterinary and Food Sciences University of Idaho Moscow Idaho USA
| | - David Broussard
- Department of Biology Lycoming College Williamsport Pennsylvania USA
| | - Theodore G. Manno
- Science Department Catalina Foothills High School Tucson Arizona USA
| | - Nandini Rajamani
- Indian Institute of Science Education and Research Tirupati Andhra Pradesh India
| | - Claire Saraux
- Département Ecologie, Physiologie et Ethologie Institut Pluridisciplinaire Hubert Curien, CNRS Strasbourg France
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40
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Auteri GG. A conceptual framework to integrate cold-survival strategies: torpor, resistance and seasonal migration. Biol Lett 2022; 18:20220050. [PMID: 35506240 PMCID: PMC9065958 DOI: 10.1098/rsbl.2022.0050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Freezing temperatures are inherently challenging for life, which is water based. How species cope with these conditions fundamentally shapes ecological and evolutionary processes. Despite this, there is no comprehensive conceptual framework for cold-survival strategies-seasonal migration, cold resistance and torpor. Here, I propose a framework with four components for conceptualizing and quantifying cold-survival strategies. Cold-survival strategies are (i) collectively encompassed by the proposed framework, and that this full breadth of strategies should be considered in focal species or systems (comprehensive consideration). These strategies also (ii) exist on a spectrum, such that species can exhibit partial use of strategies, (iii) are non-exclusive, such that some species use multiple strategies concurrently (combined use) and (iv) should collectively vary inversely and proportionally with one another when controlling for the external environment (e.g. when considering species that occur in sympatry in their summer range), such that use of one strategy reduces, collectively, the use of others (proportional use). This framework is relevant to understanding fundamental patterns and processes in evolution, ecology, physiology and conservation biology.
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Affiliation(s)
- Giorgia G Auteri
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
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41
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Watts AJ, Storey KB. Peripheral circadian gene activity is altered during hibernation in the thirteen-lined ground squirrel. Cryobiology 2022; 107:48-56. [DOI: 10.1016/j.cryobiol.2022.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 01/08/2023]
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42
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Carrier B, Hamel S, Garel M, Côté SD. Coping with seasonality: dynamics of adult body mass and survival in an alpine hibernator. OIKOS 2022. [DOI: 10.1111/oik.09043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Béatrice Carrier
- Dépt de Biologie and Centre d'Études Nordiques, Univ. Laval Québec QC Canada
| | | | - Mathieu Garel
- Office Français de la Biodiversité, Unité Ongulés Sauvages Gières France
| | - Steeve D. Côté
- Dépt de Biologie and Centre d'Études Nordiques, Univ. Laval Québec QC Canada
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43
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Alston JM, Dillon ME, Keinath DA, Abernethy IM, Goheen JR. Daily torpor reduces the energetic consequences of microhabitat selection for a widespread bat. Ecology 2022; 103:e3677. [PMID: 35262926 PMCID: PMC9286574 DOI: 10.1002/ecy.3677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 12/16/2021] [Indexed: 11/25/2022]
Abstract
Homeothermy requires increased metabolic rates as temperatures decline below the thermoneutral zone, so homeotherms typically select microhabitats within or near their thermoneutral zones during periods of inactivity. However, many mammals and birds are heterotherms that relax internal controls on body temperature and go into torpor when maintaining a high, stable body temperature, which is energetically costly. Such heterotherms should be less tied to microhabitats near their thermoneutral zones and, because heterotherms spend more time in torpor and expend less energy at colder temperatures, heterotherms may even select microhabitats in which temperatures are well below their thermoneutral zones. We studied how temperature and daily torpor influence the selection of microhabitats (i.e., diurnal roosts) by a heterothermic bat (Myotis thysanodes). We (1) quantified the relationship between ambient temperature and daily duration of torpor, (2) simulated daily energy expenditure over a range of microhabitat temperatures, and (3) quantified the influence of microhabitat temperature on microhabitat selection. In addition, warm microhabitats substantially reduced the energy expenditure of simulated homeothermic bats, and heterothermic bats modulated their use of daily torpor to maintain a constant level of energy expenditure across microhabitats of different temperatures. Daily torpor expanded the range of energetically economical microhabitats, such that microhabitat selection was independent of microhabitat temperature. Our work adds to a growing literature documenting the functions of torpor beyond its historical conceptualization as a last‐resort measure to save energy during periods of extended or acute energetic stress.
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Affiliation(s)
- Jesse M Alston
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA.,Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming, USA.,Center for Advanced Systems Understanding (CASUS), Görlitz, DEU, Germany
| | - Michael E Dillon
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Douglas A Keinath
- Wyoming Ecological Services Field Office, United States Fish and Wildlife Service, Cheyenne, Wyoming, USA
| | - Ian M Abernethy
- Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming, USA
| | - Jacob R Goheen
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
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44
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Gharnit E, Dammhahn M, Garant D, Réale D. Resource Availability, Sex, and Individual Differences in Exploration Drive Individual Diet Apecialization. Am Nat 2022; 200:1-16. [DOI: 10.1086/719669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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45
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Klüg-Baerwald BJ, Lausen CL, Wissel B, Brigham RM. Meet You at the Local Watering Hole? No Use of an Artificial Water Resource, and Evidence of Dehydration in Hibernating Bats in the Prairies. ACTA CHIROPTEROLOGICA 2022. [DOI: 10.3161/15081109acc2021.23.2.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Cori L. Lausen
- Wildlife Conservation Society of Canada, PO Box 606, Kaslo, BC V0G 1M0 Canada
| | - Bjoern Wissel
- Department of Biology, University of Regina, Regina, SK S4S 0A2 Canada
| | - R. Mark Brigham
- Department of Biology, University of Regina, Regina, SK S4S 0A2 Canada
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46
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Meier F, Grosche L, Reusch C, Runkel V, van Schaik J, Kerth G. Long-term individualized monitoring of sympatric bat species reveals distinct species- and demographic differences in hibernation phenology. BMC Ecol Evol 2022; 22:7. [PMID: 35090401 PMCID: PMC8796590 DOI: 10.1186/s12862-022-01962-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/13/2022] [Indexed: 11/21/2022] Open
Abstract
Background Hibernation allows species to conserve energy and thereby bridge unfavorable environmental conditions. At the same time, hibernation imposes substantial ecological and physiological costs. Understanding how hibernation timing differs within and between species can provide insights into the underlying drivers of this trade-off. However, this requires individualized long-term data that are often unavailable. Here, we used automatic monitoring techniques and a reproducible analysis pipeline to assess the individualized hibernation phenology of two sympatric bat species. Our study is based on data of more than 1100 RFID-tagged Daubenton’s bats (Myotis daubentonii) and Natterer’s bats (Myotis nattereri) collected over seven years at a hibernaculum in Germany. We used linear mixed models to analyze species-, sex- and age-specific differences in entrance, emergence and duration of the longest continuous period spent in the hibernaculum. Results Overall, Daubenton’s bats entered the hibernaculum earlier and emerged later than Natterer’s bats, resulting in a nearly twice as long hibernation duration. In both species, adult females entered earlier and emerged from hibernation later than adult males. Hibernation duration was shorter for juveniles than adults with the exception of adult male Natterer’s bats whose hibernation duration was shortest of all classes. Finally, hibernation timing differed among years, but yearly variations in entrance and emergence timing were not equally shifted in both species. Conclusions Our results suggest that even in sympatric species, and across sex and age classes, hibernation timing may be differentially affected by environmental conditions. This highlights the necessity of using individualized information when studying the impact of changing environments on hibernation phenology. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-01962-6.
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Affiliation(s)
- Frauke Meier
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany.
| | - Leo Grosche
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
| | - Christine Reusch
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany.,Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Volker Runkel
- BVF Bundesverband für Fledermauskunde Deutschland e.V., Erfurt, Germany
| | - Jaap van Schaik
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
| | - Gerald Kerth
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
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47
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Blanco MB, Greene LK, Klopfer PH, Lynch D, Browning J, Ehmke EE, Yoder AD. Body Mass and Tail Girth Predict Hibernation Expression in Captive Dwarf Lemurs. Physiol Biochem Zool 2022; 95:122-129. [PMID: 34986077 DOI: 10.1086/718222] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractHibernation, a metabolic strategy, allows individuals to reduce energetic demands in times of energetic deficits. Hibernation is pervasive in nature, occurring in all major mammalian lineages and geographical regions; however, its expression is variable across species, populations, and individuals, suggesting that trade-offs are at play. Whereas hibernation reduces energy expenditure, energetically expensive arousals may impose physiological burdens. The torpor optimization hypothesis posits that hibernation should be expressed according to energy availability. The greater the energy surplus, the lower the hibernation output. The thrifty female hypothesis, a variation of the torpor optimization hypothesis, states that females should conserve more energy because of their more substantial reproductive costs. Contrarily, if hibernation's benefits offset its costs, hibernation may be maximized rather than optimized (e.g., hibernators with greater fat reserves could afford to hibernate longer). We assessed torpor expression in captive dwarf lemurs, primates that are obligate, seasonal, and tropical hibernators. Across 4.5 mo in winter, we subjected eight individuals at the Duke Lemur Center to conditions conducive to hibernation, recorded estimates of skin temperature hourly (a proxy for torpor), and determined body mass and tail fat reserves bimonthly. Across and between consecutive weigh-ins, heavier dwarf lemurs spent less time in torpor and lost more body mass. At equivalent body mass, females spent more time torpid and better conserved energy than did males. Although preliminary, our results support the torpor optimization and thrifty female hypotheses, suggesting that individuals optimize rather than maximize torpor according to body mass. These patterns are consistent with hibernation phenology in Madagascar, where dwarf lemurs hibernate longer in more seasonal habitats.
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48
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Boyles J, Johnson E, Fuller NW, Silas K, Hou L, Frick WF, McGuire L. Behavioural microclimate selection and physiological responses to environmental conditions in a hibernating bat. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hibernators adjust the expression of torpor behaviourally and physiologically to balance the benefits of energy conservation in hibernation against the physiological and ecological costs. Small fat-storing species, like many cave-hibernating bats, have long been thought to be highly constrained in their expression of hibernation because they must survive winter relying only on endogenous energy stores. We evaluated behavioural microclimate selection in tri-colored bats (Perimyotis subflavus (Cuvier, 1832)) across a three-month hibernation experiment under laboratory conditions. We also opportunistically tested for evidence of acclimatization in torpid metabolic rate (TMR). When given access to gradients in microclimate, bats tended to choose the warmest temperature available (11°C) while almost completely avoiding the driest condition available (85% relative humidity at 8°C). Further, bats held at different temperatures over the course of the hibernation showed no differences in TMR when measured under common conditions at the end of hibernation. Taken together, our results suggest selective pressures to conserve energy during hibernation are not overwhelmingly strong and further support the proposition that optimal expression of hibernation is something less than the maximal expression of hibernation unless the animal is nearing starvation.
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Affiliation(s)
- Justin Boyles
- Southern Illinois University, Cooperative Wildlife Research Lab, 1125 Lincoln Dr, Room 251, Carbodale, Illinois, United States, 62901
| | - Emily Johnson
- Texas Tech University, 6177, Lubbock, Texas, United States
| | | | - Kirk Silas
- Texas Tech University, 6177, Lubbock, Texas, United States
| | - Lily Hou
- University of Waterloo, 8430, Waterloo, Ontario, Canada
| | | | - Liam McGuire
- University of Waterloo, 8430, Department of Biology, Waterloo, Ontario, Canada, N2L 3G1
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49
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Genoud M. The seasonal variation of basal metabolic rate is related to the expression of torpor among small mammals. J Therm Biol 2022; 104:103197. [DOI: 10.1016/j.jtherbio.2022.103197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 10/19/2022]
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50
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Reher S, Rabarison H, Montero BK, Turner JM, Dausmann KH. Disparate roost sites drive intraspecific physiological variation in a Malagasy bat. Oecologia 2021; 198:35-52. [PMID: 34951669 PMCID: PMC8803705 DOI: 10.1007/s00442-021-05088-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/21/2021] [Indexed: 11/07/2022]
Abstract
Many species are widely distributed and individual populations can experience vastly different environmental conditions over seasonal and geographic scales. With such a broad ecological reality, datasets with limited spatial and temporal resolution may not accurately represent a species and could lead to poorly informed management decisions. Because physiological flexibility can help species tolerate environmental variation, we studied the physiological responses of two separate populations of Macronycteris commersoni, a bat widespread across Madagascar, in contrasting seasons. The populations roost under the following dissimilar conditions: either a hot, well-buffered cave or within open foliage, unprotected from the local weather. We found that flexible torpor patterns, used in response to prevailing ambient temperature and relative humidity, were central to keeping energy budgets balanced in both populations. While bats’ metabolic rate during torpor and rest did not differ between roosts, adjusting torpor frequency, duration and timing helped bats maintain body condition. Interestingly, the exposed forest roost induced extensive use of torpor, which exceeded the torpor frequency of overwintering bats that stayed in the cave for months and consequently minimised daytime resting energy expenditure in the forest. Our current understanding of intraspecific physiological variation is limited and physiological traits are often considered to be fixed. The results of our study therefore highlight the need for examining species at broad environmental scales to avoid underestimating a species’ full capacity for withstanding environmental variation, especially in the face of ongoing, disruptive human interference in natural habitats.
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Affiliation(s)
- Stephanie Reher
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany.
| | - Hajatiana Rabarison
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany.,Mention Zoologie et Biodiversité Animale, Faculté des Sciences, Université d'Antananarivo, Antananarivo, Madagascar
| | - B Karina Montero
- Biodiversity Research Institute, Campus of Mieres, Universidad de Oviedo, Mieres, Spain.,Animal Ecology and Conservation, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - James M Turner
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland, South Lanarkshire, Scotland, UK
| | - Kathrin H Dausmann
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
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