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Nowack J, Stawski C, Geiser F, Levesque DL. Rare and Opportunistic Use of Torpor in Mammals-An Echo from the Past? Integr Comp Biol 2023; 63:1049-1059. [PMID: 37328423 PMCID: PMC10714912 DOI: 10.1093/icb/icad067] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/18/2023] Open
Abstract
Torpor was traditionally seen as a winter survival mechanism employed by animals living in cold and highly seasonal habitats. Although we now know that torpor is also used by tropical and subtropical species, and in response to a variety of triggers, torpor is still largely viewed as a highly controlled, seasonal mechanism shown by Northern hemisphere species. To scrutinize this view, we report data from a macroanalysis in which we characterized the type and seasonality of torpor use from mammal species currently known to use torpor. Our findings suggest that predictable, seasonal torpor patterns reported for Northern temperate and polar species are highly derived forms of torpor expression, whereas the more opportunistic and variable forms of torpor that we see in tropical and subtropical species are likely closer to the patterns expressed by ancestral mammals. Our data emphasize that the torpor patterns observed in the tropics and subtropics should be considered the norm and not the exception.
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Affiliation(s)
- Julia Nowack
- School of Biological and Environmental Sciences, Liverpool John Moores University, L3 3AF Liverpool, UK
| | - Clare Stawski
- School of Science, Technology and Engineering, University of the Sunshine Coast (USC), Maroochydore DC, QLD 4558, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
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2
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Sørås R, Fjelldal MA, Bech C, van der Kooij J, Eldegard K, Stawski C. High latitude northern bats (Eptesicus nilssonii) reveal adaptations to both high and low ambient temperatures. J Exp Biol 2023; 226:jeb245260. [PMID: 37815465 DOI: 10.1242/jeb.245260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 09/26/2023] [Indexed: 10/11/2023]
Abstract
Insectivorous bats at northern latitudes need to cope with long periods of no food for large parts of the year. Hence, bats which are resident at northern latitudes throughout the year will need to undergo a long hibernation season and a short reproductive season where foraging time is limited by extended daylight periods. Eptesicus nilssonii is the northernmost occurring bat species worldwide and hibernates locally when ambient temperatures (Ta) limit prey availability. Therefore, we investigated the energy spent maintaining normothermy at different Ta, as well as how much bats limit energy expenditure while in torpor. We found that, despite being exposed to Ta as low as 1.1°C, bats did not increase torpid metabolic rate, thus indicating that E. nilssonii can survive and hibernate at low ambient temperatures. Furthermore, we found a lower critical temperature (Tlc) of 27.8°C, which is lower than in most other vespertilionid bats, and we found no indication of any metabolic response to Ta up to 37.1°C. Interestingly, carbon dioxide production increased with increasing Ta above the Tlc, presumably caused by a release of retained CO2 in bats that remained in torpor for longer and aroused at Ta above the Tlc. Our results indicate that E. nilssonii can thermoconform at near-freezing Ta, and hence maintain longer torpor bouts with limited energy expenditure, yet also cope with high Ta when sun exposed in roosts during long summer days. These physiological traits are likely to enable the species to cope with ongoing and predicted climate change.
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Affiliation(s)
- Rune Sørås
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - Mari Aas Fjelldal
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - Claus Bech
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - Jeroen van der Kooij
- Nature Education, Research and Consultancy van der Kooij, Rudsteinveien 67, Slattum NO-1480, Norway
| | - Katrine Eldegard
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, Ås NO-1433, Norway
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia
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3
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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4
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Kieffer L, Sørås R, Ciesielski TM, Stawski C. Species and reproductive status influence element concentrations in bat fur. Environ Pollut 2023; 333:122092. [PMID: 37348695 DOI: 10.1016/j.envpol.2023.122092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023]
Abstract
To assess the impact of increasing pollutant levels on wildlife, we measured chemical contaminant loads in bats with different habitat and dietary preferences. Samples were taken from the fur of bats (Eptesicus nilssonii, Myotis brandtii, Myotis mystacinus and Plecotus auritus) to measure concentrations of 55 elements by inductively coupled plasma mass spectrometry (ICP-MS). Variations in element concentrations between different bat groups (species, sex, reproductive status) were analysed with a focus on arsenic (As), mercury (Hg) and lead (Pb) as these are known to cause specific health concerns in wildlife. For M. brandtii we found the highest As concentrations, especially in lactating bats, with a maximum exceeding those from other studies where bats had compromised health. Whereas for M. mystacinus there was a negative correlation between body condition index (BCI) and As concentration, indicating a potential danger for bats in the study area. In M. mystacinus and M. brandtii Hg concentrations were higher for sixteen individuals than in other studies where bats suffered genotoxic effects, although median levels were still below this threshold. Lactating bats from P. auritus and M. brandtii had higher Hg concentrations than bats of other reproductive status, which could endanger offspring as Hg can be transferred through lactation. In females from M. mystacinus Pb concentrations were more than three times higher compared to males. There was also a negative correlation between Pb concentration and BCI, which could mean that Pb has an adverse effect on health. Although many other biotic and abiotic factors should be considered, some of the variations in element concentrations could be due to different behaviours (foraging, roosting, etc.) in the studied species. The high levels of chemical contamination in some of the bats in our study, particularly reproductive individuals, is of conservation concern as bats are important agents for insect control.
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Affiliation(s)
- Luc Kieffer
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway
| | - Rune Sørås
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway
| | - Tomasz M Ciesielski
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway; Department of Arctic Technology, The University Centre in Svalbard (UNIS), P.O. Box 156, 9171, Longyearbyen, Norway
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway; School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland, 4558, Australia.
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5
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Froidevaux JSP, Toshkova N, Barbaro L, Benítez-López A, Kerbiriou C, Le Viol I, Pacifici M, Santini L, Stawski C, Russo D, Dekker J, Alberdi A, Amorim F, Ancillotto L, Barré K, Bas Y, Cantú-Salazar L, Dechmann DKN, Devaux T, Eldegard K, Fereidouni S, Furmankiewicz J, Hamidovic D, Hill DL, Ibáñez C, Julien JF, Juste J, Kaňuch P, Korine C, Laforge A, Legras G, Leroux C, Lesiński G, Mariton L, Marmet J, Mata VA, Mifsud CM, Nistreanu V, Novella-Fernandez R, Rebelo H, Roche N, Roemer C, Ruczyński I, Sørås R, Uhrin M, Vella A, Voigt CC, Razgour O. A species-level trait dataset of bats in Europe and beyond. Sci Data 2023; 10:253. [PMID: 37137926 PMCID: PMC10156679 DOI: 10.1038/s41597-023-02157-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/17/2023] [Indexed: 05/05/2023] Open
Abstract
Knowledge of species' functional traits is essential for understanding biodiversity patterns, predicting the impacts of global environmental changes, and assessing the efficiency of conservation measures. Bats are major components of mammalian diversity and occupy a variety of ecological niches and geographic distributions. However, an extensive compilation of their functional traits and ecological attributes is still missing. Here we present EuroBaTrait 1.0, the most comprehensive and up-to-date trait dataset covering 47 European bat species. The dataset includes data on 118 traits including genetic composition, physiology, morphology, acoustic signature, climatic associations, foraging habitat, roost type, diet, spatial behaviour, life history, pathogens, phenology, and distribution. We compiled the bat trait data obtained from three main sources: (i) a systematic literature and dataset search, (ii) unpublished data from European bat experts, and (iii) observations from large-scale monitoring programs. EuroBaTrait is designed to provide an important data source for comparative and trait-based analyses at the species or community level. The dataset also exposes knowledge gaps in species, geographic and trait coverage, highlighting priorities for future data collection.
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Affiliation(s)
- Jérémy S P Froidevaux
- University of Stirling, Biological and Environmental Sciences, Faculty of Natural Sciences, FK9 4LJ, Stirling, UK.
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France.
- School of Biological Sciences, University of Bristol, Life Sciences Building, BS8 1TQ, Bristol, UK.
| | - Nia Toshkova
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd., 1000, Sofia, Bulgaria
- National Museum of Natural History at the Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Luc Barbaro
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
- DYNAFOR, INRAE-INPT, University of Toulouse, Castanet-Tolosan, France
| | - Ana Benítez-López
- Integrative Ecology Group, Estación Biológica de Doñana (EBD-CSIC), Sevilla, Spain
- Department of Zoology, University of Granada, Granada, Spain
| | - Christian Kerbiriou
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Isabelle Le Viol
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Michela Pacifici
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Luca Santini
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland, 4558, Australia
| | - Danilo Russo
- Laboratory of Animal Ecology and Evolution (AnEcoEvo), Dipartimento di Agraria, Università degli Studi di Napoli Federico II, via Università, 100, 80055, Portici (Napoli), Italy.
| | - Jasja Dekker
- Jasja Dekker Dierecologie BV, Arnhem, the Netherlands
| | - Antton Alberdi
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Francisco Amorim
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Leonardo Ancillotto
- Laboratory of Animal Ecology and Evolution (AnEcoEvo), Dipartimento di Agraria, Università degli Studi di Napoli Federico II, via Università, 100, 80055, Portici (Napoli), Italy
| | - Kévin Barré
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Yves Bas
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
- CEFE, Univ. Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Lisette Cantú-Salazar
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation, 41 rue du Brill, L-4422, Belvaux, Luxemburg
| | - Dina K N Dechmann
- Max Planck Institute of Animal Behavior, Department of Migration, Am Obstberg 1, 78315, Radolfzell, Germany
- University of Konstanz, Department of Biology, Universitätsstr. 10, 78464, Konstanz, Germany
| | - Tiphaine Devaux
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Katrine Eldegard
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432, Ås, Norway
| | - Sasan Fereidouni
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Joanna Furmankiewicz
- Department of Behavioural Ecology, Faculty of Biological Sciences, University of Wroclaw, Sienkiewicza 21, 50-335, Wroclaw, Poland
| | - Daniela Hamidovic
- Ministry of Economy and Sustainable Development, Institute for Environment and Nature, Radnička cesta 80, HR-10000, Zagreb, Croatia
- Croatian Biospeleological Society, Rooseveltov trg 6, HR-10000, Zagreb, Croatia
| | - 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
| | - Carlos Ibáñez
- Department Evolutionary Ecology, Estación Biológica de Doñana (EBD-CSIC), Sevilla, Spain
| | - Jean-François Julien
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Javier Juste
- Department Evolutionary Ecology, Estación Biológica de Doñana (EBD-CSIC), Sevilla, Spain
- CIBER de Epidemiología y Salud Pública, CIBERESP, 28220, Madrid, Spain
| | - Peter Kaňuch
- Institute of Forest Ecology, Slovak Academy of Sciences, Zvolen, Slovakia
| | - Carmi Korine
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000, Midreshet Ben-Gurion, Israel
| | - Alexis Laforge
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Gaëlle Legras
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Camille Leroux
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
- Auddicé Biodiversité- ZAC du Chevalement, 5 rue des Molettes, 59286, Roost-Warendin, France
| | - Grzegorz Lesiński
- Institute of Animal Science, Warsaw University of Life Sciences (SGGW), Ciszewskiego 8, 02-787, Warsaw, Poland
| | - Léa Mariton
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS, MNHN, IRD, 61 Rue Buffon, 75005, Paris, France
| | - Julie Marmet
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
| | - Vanessa A Mata
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Clare M Mifsud
- Conservation Biology Research Group, Biology Department, University of Malta, MSD2080, Msida, Malta
| | | | - Roberto Novella-Fernandez
- Technical University of Munich, Terrestrial Ecology Research Group, Department for Life Science Systems, School of Life Sciences, Freising, Germany
| | - Hugo Rebelo
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
- ESS, Polytechnic Institute of Setúbal, Campus do IPS - Estefanilha, 2910-761, Setúbal, Portugal
| | - Niamh Roche
- Bat Conservation Ireland, Carmichael House, 4-7, North Brunswick Street, Dublin, D07 RHA8, Ireland
| | - Charlotte Roemer
- Centre d'Ecologie et des Sciences de la Conservation (CESCO, UMR 7204), CNRS, MNHN, Sorbonne-Université, 29900 Concarneau, 75005, Paris, France
- CEFE, Univ. Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Ireneusz Ruczyński
- Mammal Research Institute Polish Academy of Sciences, Stoczek 1, 17-230, Białowieża, Poland
| | - Rune Sørås
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway
| | - Marcel Uhrin
- Institute of Biology and Ecology, Faculty of Science, P. J, Šafárik University in Košice, Košice, Slovakia
| | - Adriana Vella
- Conservation Biology Research Group, Biology Department, University of Malta, MSD2080, Msida, Malta
| | - Christian C Voigt
- Department Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315, Berlin, Germany
| | - Orly Razgour
- Biosciences, University of Exeter, Streatham Campus, Hatherly Laboratories, Prince of Wales Road, Exeter, EX4 4PS, UK.
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Nafstad ÅM, Rønning B, Aase K, Ringsby TH, Hagen IJ, Ranke PS, Kvalnes T, Stawski C, Räsänen K, Saether BE, Muff S, Jensen H. Spatial variation in the evolutionary potential and constraints of basal metabolic rate and body mass in a wild bird. J Evol Biol 2023; 36:650-662. [PMID: 36811205 DOI: 10.1111/jeb.14164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/09/2022] [Accepted: 12/11/2022] [Indexed: 02/24/2023]
Abstract
An organism's energy budget is strongly related to resource consumption, performance, and fitness. Hence, understanding the evolution of key energetic traits, such as basal metabolic rate (BMR), in natural populations is central for understanding life-history evolution and ecological processes. Here we used quantitative genetic analyses to study evolutionary potential of BMR in two insular populations of the house sparrow (Passer domesticus). We obtained measurements of BMR and body mass (Mb ) from 911 house sparrows on the islands of Leka and Vega along the coast of Norway. These two populations were the source populations for translocations to create an additional third, admixed 'common garden' population in 2012. With the use of a novel genetic group animal model concomitant with a genetically determined pedigree, we differentiate genetic and environmental sources of variation, thereby providing insight into the effects of spatial population structure on evolutionary potential. We found that the evolutionary potential of BMR was similar in the two source populations, whereas the Vega population had a somewhat higher evolutionary potential of Mb than the Leka population. BMR was genetically correlated with Mb in both populations, and the conditional evolutionary potential of BMR (independent of body mass) was 41% (Leka) and 53% (Vega) lower than unconditional estimates. Overall, our results show that there is potential for BMR to evolve independently of Mb , but that selection on BMR and/or Mb may have different evolutionary consequences in different populations of the same species.
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Affiliation(s)
- Ådne M Nafstad
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Bernt Rønning
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Teacher Education, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Kenneth Aase
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Mathematical Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Thor Harald Ringsby
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ingerid J Hagen
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Norwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - Peter S Ranke
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Thomas Kvalnes
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,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
| | - Katja Räsänen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylän, Finland
| | - Bernt-Erik Saether
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Stefanie Muff
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Mathematical Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Henrik Jensen
- Centre for Biodiversity Dynamics (CBD), Trondheim, Norway.,Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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7
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Sørås R, Fjelldal MA, Bech C, van der Kooij J, Skåra KH, Eldegard K, Stawski C. State dependence of arousal from torpor in brown long-eared bats (Plecotus auritus). J Comp Physiol B 2022; 192:815-827. [PMID: 35972527 PMCID: PMC9550697 DOI: 10.1007/s00360-022-01451-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 06/08/2022] [Accepted: 07/19/2022] [Indexed: 11/02/2022]
Abstract
To cope with periods of low food availability and unsuitable environmental conditions (e.g., short photoperiod or challenging weather), many heterothermic mammals can readily go into torpor to save energy. However, torpor also entails several potential costs, and quantitative energetics can, therefore, be influenced by the individual state, such as available energy reserves. We studied the thermal energetics of brown long-eared bats (Plecotus auritus) in the northern part of its distributional range, including torpor entry, thermoregulatory ability during torpor and how they responded metabolically to an increasing ambient temperature (Ta) during arousal from torpor. Torpor entry occurred later in bats with higher body mass (Mb). During torpor, only 10 out of 21 bats increased oxygen consumption (V̇O2) to a greater extent above the mean torpor metabolic rates (TMR) when exposed to low Ta. The slope of the torpid thermoregulatory curve was shallower than that of resting metabolic rate (RMR) during normothermic conditions, indicating a higher thermal insulation during torpor. During exposure to an increasing Ta, all bats increased metabolic rate exponentially, but the bats with higher Mb aroused at a lower Ta than those with lower Mb. In bats with low Mb, arousal was postponed to an Ta above the lower critical temperature of the thermoneutral zone. Our results demonstrate that physiological traits, which are often considered fixed, can be more flexible than previously assumed and vary with individual state. Thus, future studies of thermal physiology should to a greater extent take individual state-dependent effects into account.
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Affiliation(s)
- Rune Sørås
- Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, NO, Norway.
| | - Mari Aas Fjelldal
- Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, NO, Norway
| | - Claus Bech
- Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, NO, Norway
| | - Jeroen van der Kooij
- Nature Education, Research and Consultancy van der Kooij, Rudsteinveien 67, 1480, Slattum, NO, Norway
| | - Karoline H Skåra
- Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, NO, Norway
- Centre for Fertility and Health, Norwegian Institute of Public Health, Skøyen, P.O. Box 222, Oslo, 0213, NO, Norway
| | - Katrine Eldegard
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, 1433, Ås, NO, Norway
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, NO, Norway
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD, 4558, Australia
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9
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Doherty TS, Geary WL, Jolly CJ, Macdonald KJ, Miritis V, Watchorn DJ, Cherry MJ, Conner LM, González TM, Legge SM, Ritchie EG, Stawski C, Dickman CR. Fire as a driver and mediator of predator-prey interactions. Biol Rev Camb Philos Soc 2022; 97:1539-1558. [PMID: 35320881 PMCID: PMC9546118 DOI: 10.1111/brv.12853] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 01/08/2023]
Abstract
Both fire and predators have strong influences on the population dynamics and behaviour of animals, and the effects of predators may either be strengthened or weakened by fire. However, knowledge of how fire drives or mediates predator–prey interactions is fragmented and has not been synthesised. Here, we review and synthesise knowledge of how fire influences predator and prey behaviour and interactions. We develop a conceptual model based on predator–prey theory and empirical examples to address four key questions: (i) how and why do predators respond to fire; (ii) how and why does prey vulnerability change post‐fire; (iii) what mechanisms do prey use to reduce predation risk post‐fire; and (iv) what are the outcomes of predator–fire interactions for prey populations? We then discuss these findings in the context of wildlife conservation and ecosystem management before outlining priorities for future research. Fire‐induced changes in vegetation structure, resource availability, and animal behaviour influence predator–prey encounter rates, the amount of time prey are vulnerable during an encounter, and the conditional probability of prey death given an encounter. How a predator responds to fire depends on fire characteristics (e.g. season, severity), their hunting behaviour (ambush or pursuit predator), movement behaviour, territoriality, and intra‐guild dynamics. Prey species that rely on habitat structure for avoiding predation often experience increased predation rates and lower survival in recently burnt areas. By contrast, some prey species benefit from the opening up of habitat after fire because it makes it easier to detect predators and to modify their behaviour appropriately. Reduced prey body condition after fire can increase predation risk either through impaired ability to escape predators, or increased need to forage in risky areas due to being energetically stressed. To reduce risk of predation in the post‐fire environment, prey may change their habitat use, increase sheltering behaviour, change their movement behaviour, or use camouflage through cryptic colouring and background matching. Field experiments and population viability modelling show instances where fire either amplifies or does not amplify the impacts of predators on prey populations, and vice versa. In some instances, intense and sustained post‐fire predation may lead to local extinctions of prey populations. Human disruption of fire regimes is impacting faunal communities, with consequences for predator and prey behaviour and population dynamics. Key areas for future research include: capturing data continuously before, during and after fires; teasing out the relative importance of changes in visibility and shelter availability in different contexts; documenting changes in acoustic and olfactory cues for both predators and prey; addressing taxonomic and geographic biases in the literature; and predicting and testing how changes in fire‐regime characteristics reshape predator–prey interactions. Understanding and managing the consequences for predator–prey communities will be critical for effective ecosystem management and species conservation in this era of global change.
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Affiliation(s)
- Tim S Doherty
- School of Life and Environmental Sciences, Heydon-Laurence Building A08, The University of Sydney, Sydney, NSW, 2006, Australia
| | - William L Geary
- Biodiversity Strategy and Knowledge Branch, Biodiversity Division, Department of Environment, Land, Water and Planning, 8 Nicholson Street, East Melbourne, VIC, 3002, Australia.,Centre for Integrative Ecology, School of Life and Environmental Sciences (Burwood Campus), Deakin University, 75 Pigdons Road, Waurn Ponds, VIC, 3216, Australia
| | - Chris J Jolly
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Gungalman Drive, Albury, NSW, 2640, Australia.,School of Natural Sciences, G17, Macquarie University, 205B Culloden Road, Macquarie Park, NSW, 2109, Australia
| | - Kristina J Macdonald
- Centre for Integrative Ecology, School of Life and Environmental Sciences (Burwood Campus), Deakin University, 75 Pigdons Road, Waurn Ponds, VIC, 3216, Australia
| | - Vivianna Miritis
- School of Life and Environmental Sciences, Heydon-Laurence Building A08, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Darcy J Watchorn
- Centre for Integrative Ecology, School of Life and Environmental Sciences (Burwood Campus), Deakin University, 75 Pigdons Road, Waurn Ponds, VIC, 3216, Australia
| | - Michael J Cherry
- Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, 700 University Boulevard, MSC 218, Kingsville, TX, 78363, U.S.A
| | - L Mike Conner
- The Jones Center at Ichauway, 3988 Jones Center Drive, Newton, GA, 39870, U.S.A
| | - Tania Marisol González
- Laboratorio de Ecología del Paisaje y Modelación de Ecosistemas ECOLMOD, Departamento de Biología, Facultad de Ciencias, Universidad Nacional de Colombia, Edificio 421, Bogotá, 111321, Colombia
| | - Sarah M Legge
- Fenner School of Environment & Society, The Australian National University, Linnaeus Way, Canberra, ACT, 2601, Australia.,Centre for Biodiversity Conservation Science, University of Queensland, Level 5 Goddard Building, St Lucia, QLD, 4072, Australia
| | - Euan G Ritchie
- Centre for Integrative Ecology, School of Life and Environmental Sciences (Burwood Campus), Deakin University, 75 Pigdons Road, Waurn Ponds, VIC, 3216, Australia
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway.,School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD, 4558, Australia
| | - Chris R Dickman
- School of Life and Environmental Sciences, Heydon-Laurence Building A08, The University of Sydney, Sydney, NSW, 2006, Australia
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10
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Chenery M, Geiser F, Stawski C. OUP accepted manuscript. J Mammal 2022; 103:826-834. [PMID: 36110387 PMCID: PMC9469929 DOI: 10.1093/jmammal/gyac022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 02/08/2022] [Indexed: 11/14/2022] Open
Abstract
Insectivorous bats are particularly susceptible to heat loss due to their relatively large surface area to volume ratio. Therefore, to maintain a high normothermic body temperature, bats require large amounts of energy for thermoregulation. This can be energetically challenging for small bats during cold periods as heat loss is augmented and insect prey is reduced. To conserve energy many bats enter a state of torpor characterized by a controlled reduction of metabolism and body temperature in combination with selecting roosts based upon thermal properties. Our study aimed to quantify torpor patterns and roost preferences of free-ranging little forest bats (Vespadelus vulturnus) during winter to identify physiological and behavioral mechanisms used by this species for survival of the cold season. All bats captured were male (body mass 4.9 ± 0.7 g, n = 6) and used torpor on every day monitored, with bouts lasting up to 187.58 h (mean = 35.5 ± 36.7 h, n = 6, total number of samples [N] = 61). Torpor bout duration was significantly correlated with daily minimum and maximum ambient temperature, mean skin temperature, insect mass, and body mass of individuals and the multiday torpor bouts recorded in the cold qualify as hibernation. The lowest skin temperature recorded was 5.2°C, which corresponded to the lowest ambient temperature measurement of −5.8°C. Most bats chose tall, large, live Eucalyptus trees for roosting and to leave their roost for foraging on warmer days. Many individuals often switched roosts (every 3–5 days) and movements increased as spring approached (every 1–2 days). Our data suggest that V. vulturnus are capable of using the environmental temperature to gauge potential foraging opportunities and as a cue to reenter torpor when conditions are unsuitable. Importantly, frequent use of torpor and appropriate roost selection form key roles in the winter survival of these tiny bats.
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Affiliation(s)
- Melissa Chenery
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
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11
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Stawski C, Simmonds EG. Contrasting physiological responses to habitat degradation in two arboreal mammals. iScience 2021; 24:103453. [PMID: 34988391 PMCID: PMC8710554 DOI: 10.1016/j.isci.2021.103453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/14/2021] [Accepted: 11/11/2021] [Indexed: 11/19/2022] Open
Abstract
To cope with the challenges presented by habitat degradation and loss, animals must often respond by adjusting physiological and behavioral mechanisms. Here we quantified physiological and behavioral traits, including body temperature and food consumption, of two mammals with differing thermoregulatory strategies in response to changes in climate and habitat. We show that both species responded to challenging climatic conditions by increasing torpor use to save energy, yet their responses were impacted by varying vegetation levels. Sugar gliders decreased torpor use in a dense habitat likely due to a signal of greater food production and protection from predators. Conversely, eastern pygmy possums employed more torpor perhaps to build up fat reserves in anticipation of leaner times. Indeed, in dense habitat eastern pygmy possums did not alter food intake yet showed an increase in body mass, whereas sugar gliders consumed less food and lost body mass, revealing the large energetic savings provided by torpor. Physiological responses to habitat degradation differ among mammals Hibernating eastern pygmy possums employ less torpor in degraded habitat Whereas sugar gliders, daily heterotherms, employ more torpor in degraded habitat These differing responses are perhaps due to perceived predation risk
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia
- Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
- Corresponding author
| | - Emily G. Simmonds
- Department of Mathematical Sciences and Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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12
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Skåra KH, Bech C, Fjelldal MA, van der Kooij J, Sørås R, Stawski C. Energetics of whiskered bats in comparison to other bats of the family Vespertilionidae. Biol Open 2021; 10:271095. [PMID: 34338281 PMCID: PMC8353265 DOI: 10.1242/bio.058640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/14/2021] [Indexed: 11/20/2022] Open
Abstract
Bats inhabit a variety of climate types, ranging from tropical to temperate zones, and environmental differences may therefore affect the basal metabolic rate (BMR) of bats from different populations. In the present study, we provide novel data on the energetics of whiskered bats (Myotis mystacinus), which is the smallest species within Chiroptera measured to date. We investigated the thermoregulatory strategies of M. mystacinus close to the northern limits of this species' distribution range and compared these data to other vespertilionid bats living in different climates. As mammals living in colder areas experience elevated thermoregulatory costs, often leading to an increase in BMR, we hypothesised that BMR of this northern population of whiskered bats would be higher than that of bats from climates with warm environmental temperatures. From a systematic literature search we obtained BMR estimates (N=47) from 24 species within Vespertilionidae. Our metabolic measurements of M. mystacinus in Norway (body mass of 4.4 g; BMR of 1.48 ml O2 g-1 h-1) were not different from other vespertilionid bats, based on the allometric equation obtained from the systematic literature search. Further, there was no effect of environmental temperature on BMR within Vespertilionidae. How these tiny bats adapt metabolically to high latitude living is thus still an open question. Bats do have a suite of physiological strategies used to cope with the varying climates which they inhabit, and one possible factor could be that instead of adjusting BMR they could express more torpor. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Karoline H Skåra
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - Claus Bech
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - Mari Aas Fjelldal
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | | | - Rune Sørås
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology, Trondheim NO-7491, Norway
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13
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Abstract
Devastation of both natural and human habitats due to wildfires is becoming an increasingly prevalent global issue. Fire-adapted and fire-prone regions, such as California and parts of Australia, are experiencing more frequent and increasingly destructive wildfires, accompanied by longer wildfire seasons. Further, wildfires are becoming more commonplace in areas that historically do not regularly experience fire, causing an increased risk of habitat loss in less resilient ecosystems. The escalation of fire outbreaks is a result of several factors; however, at the forefront of these outbreaks is an increase in highly flammable dry vegetation due to sustained drought, a trend we will see growing in our changing climate. To mitigate the potentially detrimental outcomes of wildfires, it is imperative that we understand the response of ecosystems to fire not only from an ecological perspective, but also from a physiological perspective. Research focused on the physiological adaptations of organisms to environmental constraints caused by fire can give insight into how plants and animals respond to fire, on both short- and long-term scales. Importantly, this information needs to be adapted effectively into fire management plans to improve the recovery success of organisms after fire.
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Affiliation(s)
- Clare Stawski
- Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Anna C Doty
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
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14
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Stawski C, Geiser F. Growing Up in a Changing Climate: How Temperature Affects the Development of Morphological, Behavioral and Physiological Traits of a Marsupial Mammal. Front Physiol 2020; 11:49. [PMID: 32116761 PMCID: PMC7028820 DOI: 10.3389/fphys.2020.00049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/21/2020] [Indexed: 01/14/2023] Open
Abstract
Climate change is likely to affect many mammalian phenotypes, yet little is known whether and how phenotypic plasticity is involved in responding to thermal challenges during mammalian development. We investigated the effect of continuous cold or warm exposure during development on morphological, behavioral, and functional variables of yellow-footed antechinus (Antechinus flavipes), a semelparous Australian marsupial mammal. Captive-bred young were exposed to two ambient temperatures (T a ), cold (17°C) or warm (25°C), once weaned. Treatments were reversed and metabolic rate (MR) measurements repeated after 2 months. We measured body mass weekly, activity continuously, and MRs over a range of T a once they were adults. Growth rate was similar in both groups, but was faster in males. Antechinus in the warm group were initially more active than the cold group and decreased activity when exposed to cold, whereas the cold group increased activity when exposed to warm. Interestingly, females changed their night-time activity when T a was changed, whereas males changed their daytime activity. MRs were originally lower in the warm group in comparison to the cold group for both sexes and increased slightly for females, but not for males, after being exposed to cold. After exposure to warm T a , the MRs of the cold group decreased significantly over the entire T a -range for both sexes. Our results reveal that temperatures experienced during development can influence behavioral and physiological traits in antechinus. Such phenotypic plasticity is vital for a species that within 1 year is dependent on a single breeding event and experiences a complete population turnover.
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia.,Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
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15
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Parker CA, Geiser F, Stawski C. Thermal physiology and activity in relation to reproductive status and sex in a free-ranging semelparous marsupial. Conserv Physiol 2019; 7:coz073. [PMID: 31737272 PMCID: PMC6846706 DOI: 10.1093/conphys/coz073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 06/26/2019] [Accepted: 08/21/2019] [Indexed: 06/10/2023]
Abstract
In a changing climate, southern hemisphere mammals are predicted to face rising temperatures and aridity, resulting in food and water shortages, which may further challenge already constrained energetic demands. Especially semelparous mammals may be threatened because survival of the entire population depends on the success of a single breeding event. One of these species, the yellow-footed antechinus, Antechinus flavipes, a small, heterothermic marsupial mammal, commences reproduction during winter, when insect prey is limited and energetic constraints are high. We examined the inter-relations between thermal and foraging biology of free-ranging A. flavipes and examined whether they use torpor for energy conservation, despite the fact that reproduction and torpor are considered to be incompatible for many mammals. Females used torpor during the reproductive season, but patterns changed with reproductive status. Prior to breeding, females used frequent (86% of days), deep and long torpor that was more pronounced than any other reproductive group, including pre-mating males (64% of days). Pregnant females continued to use torpor, albeit torpor was less frequent (28% of days) and significantly shorter and shallower than before breeding. Parturient and lactating females did not express torpor. During the mating period, males reduced torpor use (24% of days). Pre-reproductive females and pre-mating males were the least active and may use torpor to minimize predator exposure and enhance fat deposition in anticipation of the energetic demands associated with impending mating, gestation and lactation. Reproductive females were most active and likely foraged and fed to promote growth and development of young. Our data show that A. flavipes are balancing energetic demands during the reproductive season by modifying torpor and activity patterns. As the timing of reproduction is fixed for this genus, it is probable that climate change will render these behavioural and physiological adaptations as inadequate and threaten this and other semelparous species.
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Affiliation(s)
- Cassandra A Parker
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
- Department of Biology, Norwegian University of Science and Technology, Trondheim 7491, Norway
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16
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Boyles JG, Levesque DL, Nowack J, Wojciechowski MS, Stawski C, Fuller A, Smit B, Tattersall GJ. An oversimplification of physiological principles leads to flawed macroecological analyses. Ecol Evol 2019; 9:12020-12025. [PMID: 31832143 PMCID: PMC6854103 DOI: 10.1002/ece3.5721] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/14/2019] [Accepted: 09/15/2019] [Indexed: 11/23/2022] Open
Affiliation(s)
- Justin G Boyles
- Cooperative Wildlife Research Laboratory Center for Ecology School of Biological Sciences Southern Illinois University Carbondale IL USA
| | | | - Julia Nowack
- School of Biological and Environmental Sciences Liverpool John Moores University Liverpool UK
| | - Michał S Wojciechowski
- Department of Vertebrate Zoology and Ecology Faculty of Biology and Environmental Protection Nicolaus Copernicus University Toruń Poland
| | - Clare Stawski
- Department of Biology Norwegian University of Science and Technology Trondheim Norway
| | - Andrea Fuller
- Brain Function Research Group School of Physiology University of the Witwatersrand Johannesburg South Africa
| | - Ben Smit
- Department of Zoology and Entomology Rhodes University Grahamstown South Africa
| | - Glenn J Tattersall
- Department of Biological Sciences Brock University St. Catharines ON Canada
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17
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Einum S, Ratikainen I, Wright J, Pélabon C, Bech C, Jutfelt F, Stawski C, Burton T. How to quantify thermal acclimation capacity? Glob Chang Biol 2019; 25:1893-1894. [PMID: 30779405 DOI: 10.1111/gcb.14598] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
The capacity of organisms to acclimate will influence their ability to cope with ongoing global changes in thermal regimes. Here we highlight methodological issues associated with recent attempts to quantify variation in acclimation capacity among taxa and environments, and describe how these may introduce bias to conclusions. We then propose a measure of thermal acclimation capacity that more directly quantifies the process of acclimation. Future studies of variation in acclimation capacity should critically evaluate whether their chosen empirical metric accurately reflects the theoretical concept of acclimation.
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Affiliation(s)
- Sigurd Einum
- Centre for Biodiversity Dynamics, Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Irja Ratikainen
- Centre for Biodiversity Dynamics, Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jonathan Wright
- Centre for Biodiversity Dynamics, Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Christophe Pélabon
- Centre for Biodiversity Dynamics, Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Claus Bech
- Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Fredrik Jutfelt
- Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Clare Stawski
- Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tim Burton
- Centre for Biodiversity Dynamics, Department of Biology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
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18
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Hume T, Geiser F, Currie SE, Körtner G, Stawski C. Responding to the weather: energy budgeting by a small mammal in the wild. Curr Zool 2019; 66:15-20. [PMID: 32467700 PMCID: PMC7245004 DOI: 10.1093/cz/zoz023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/02/2019] [Indexed: 11/12/2022] Open
Abstract
Energy conservation is paramount for small mammals because of their small size, large surface area to volume ratio, and the resultant high heat loss to the environment. To survive on limited food resources and to fuel their expensive metabolism during activity, many small mammals employ daily torpor to reduce energy expenditure during the rest phase. We hypothesized that a small terrestrial semelparous marsupial, the brown antechinus Antechinus stuartii, would maximize activity when foraging conditions were favorable to gain fat reserves before their intense breeding period, but would increase torpor use when conditions were poor to conserve these fat reserves. Female antechinus were trapped and implanted with small temperature-sensitive radio transmitters to record body temperature and to quantify torpor expression and activity patterns in the wild. Most antechinus used torpor at least once per day over the entire study period. Total daily torpor use increased and mean daily body temperature decreased significantly with a reduction in minimum ambient temperature. Interestingly, antechinus employed less torpor on days with more rain and decreasing barometric pressure. In contrast to torpor expression, activity was directly related to ambient temperature and inversely related to barometric pressure. Our results reveal that antechinus use a flexible combination of physiology and behavior that can be adjusted to manage their energy budget according to weather variables.
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Affiliation(s)
- Taylor Hume
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia
| | - Shannon E Currie
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia.,Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, Berlin, 10315, Germany
| | - Gerhard Körtner
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia.,Department of Biology, Norwegian University of Science and Technology, Trondheim, 7491, Norway
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19
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Geiser F, Bondarenco A, Currie SE, Doty AC, Körtner G, Law BS, Pavey CR, Riek A, Stawski C, Turbill C, Willis CKR, Brigham RM. Hibernation and daily torpor in Australian and New Zealand bats: does the climate zone matter? AUST J ZOOL 2019. [DOI: 10.1071/zo20025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We aim to summarise what is known about torpor use and patterns in Australian and New Zealand (ANZ) bats from temperate, tropical/subtropical and arid/semiarid regions and to identify whether and how they differ. ANZ bats comprise ~90 species from 10 families. Members of at least nine of these are known to use torpor, but detailed knowledge is currently restricted to the pteropodids, molossids, mystacinids, and vespertilionids. In temperate areas, several species can hibernate (use a sequence of multiday torpor bouts) in trees or caves mostly during winter and continue to use short bouts of torpor for the rest of the year, including while reproducing. Subtropical vespertilionids also use multiday torpor in winter and brief bouts of torpor in summer, which permit a reduction in foraging, probably in part to avoid predators. Like temperate-zone vespertilionids they show little or no seasonal change in thermal energetics during torpor, and observed changes in torpor patterns in the wild appear largely due to temperature effects. In contrast, subtropical blossom-bats (pteropodids) exhibit more pronounced daily torpor in summer than winter related to nectar availability, and this involves a seasonal change in physiology. Even in tropical areas, vespertilionids express short bouts of torpor lasting ~5 h in winter; summer data are not available. In the arid zone, molossids and vespertilionids use torpor throughout the year, including during desert heat waves. Given the same thermal conditions, torpor bouts in desert bats are longer in summer than in winter, probably to minimise water loss. Thus, torpor in ANZ bats is used by members of all or most families over the entire region, its regional and seasonal expression is often not pronounced or as expected, and it plays a key role in energy and water balance and other crucial biological functions that enhance long-term survival by individuals.
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Stawski C. Birds and bats: masters of hovering. J Exp Biol 2018. [DOI: 10.1242/jeb.170282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Geiser F, Stawski C, Doty AC, Cooper CE, Nowack J. A burning question: what are the risks and benefits of mammalian torpor during and after fires? Conserv Physiol 2018; 6:coy057. [PMID: 30323932 PMCID: PMC6181253 DOI: 10.1093/conphys/coy057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/11/2018] [Accepted: 10/08/2018] [Indexed: 06/08/2023]
Abstract
Although wildfires are increasing globally, available information on how mammals respond behaviourally and physiologically to fires is scant. Despite a large number of ecological studies, often examining animal diversity and abundance before and after fires, the reasons as to why some species perform better than others remain obscure. We examine how especially small mammals, which generally have high rates of energy expenditure and food requirements, deal with fires and post-fire conditions. We evaluate whether mammalian torpor, characterised by substantial reductions in body temperature, metabolic rate and water loss, plays a functional role in survival of mammals impacted by fires. Importantly, torpor permits small mammals to reduce their activity and foraging, and to survive on limited food. Torpid small mammals (marsupials and bats) can respond to smoke and arouse from torpor, which provides them with the possibility to evade direct exposure to fire, although their response is often slowed when ambient temperature is low. Post-fire conditions increase expression of torpor with a concomitant decrease in activity for free-ranging echidnas and small forest-dwelling marsupials, in response to reduced cover and reduced availability of terrestrial insects. Presence of charcoal and ash increases torpor use by captive small marsupials beyond food restriction alone, likely in anticipation of detrimental post-fire conditions. Interestingly, although volant bats use torpor on every day after fires, they respond by decreasing torpor duration, and increasing activity, perhaps because of the decrease in clutter and increase in foraging opportunities due to an increase in aerial insects. Our summary shows that torpor is an important tool for post-fire survival and, although the physiological and behavioural responses of small mammals to fire are complex, they seem to reflect energetic requirements and mode of foraging. We make recommendations on the conditions during management burns that are least likely to impact heterothermic mammals.
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Affiliation(s)
- Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Anna C Doty
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
| | - Christine E Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
- School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool, UK
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Stawski C. Don't want grumpy spiders? Keep it cool. J Exp Biol 2018. [DOI: 10.1242/jeb.170159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Stawski C. The bond between tropical forests and orangutans. J Exp Biol 2018. [DOI: 10.1242/jeb.170035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Doty AC, Currie SE, Stawski C, Geiser F. Can bats sense smoke during deep torpor? Physiol Behav 2018; 185:31-38. [DOI: 10.1016/j.physbeh.2017.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/24/2017] [Accepted: 12/14/2017] [Indexed: 12/28/2022]
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Stawski C. Salmon nourish their children even after death. J Exp Biol 2018. [DOI: 10.1242/jeb.169896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Nowack J, Stawski C, Körtner G, Geiser F. Physiological and behavioral responses of an arboreal mammal to smoke and charcoal-ash substrate. Physiol Behav 2018; 184:116-121. [DOI: 10.1016/j.physbeh.2017.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/08/2017] [Accepted: 11/16/2017] [Indexed: 10/18/2022]
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Stawski C, Koteja P, Sadowska ET. A Shift in the Thermoregulatory Curve as a Result of Selection for High Activity-Related Aerobic Metabolism. Front Physiol 2017; 8:1070. [PMID: 29326604 PMCID: PMC5741638 DOI: 10.3389/fphys.2017.01070] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 12/05/2017] [Indexed: 12/28/2022] Open
Abstract
According to the “aerobic capacity model,” endothermy in birds and mammals evolved as a result of natural selection favoring increased persistent locomotor activity, fuelled by aerobic metabolism. However, this also increased energy expenditure even during rest, with the lowest metabolic rates occurring in the thermoneutral zone (TNZ) and increasing at ambient temperatures (Ta) below and above this range, depicted by the thermoregulatory curve. In our experimental evolution system, four lines of bank voles (Myodes glareolus) have been selected for high swim-induced aerobic metabolism and four unselected lines have been maintained as a control. In addition to a 50% higher rate of oxygen consumption during swimming, the selected lines have also evolved a 7.3% higher mass-adjusted basal metabolic rate. Therefore, we asked whether voles from selected lines would also display a shift in the thermoregulatory curve and an increased body temperature (Tb) during exposure to high Ta. To test these hypotheses we measured the RMR and Tb of selected and control voles at Ta from 10 to 34°C. As expected, RMR within and around the TNZ was higher in selected lines. Further, the Tb of selected lines within the TNZ was greater than the Tb of control lines, particularly at the maximum measured Ta of 34°C, suggesting that selected voles are more prone to hyperthermia. Interestingly, our results revealed that while the slope of the thermoregulatory curve below the lower critical temperature (LCT) is significantly lower in the selected lines, the LCT (26.1°C) does not differ. Importantly, selected voles also evolved a higher maximum thermogenesis, but thermal conductance did not increase. As a consequence, the minimum tolerated temperature, calculated from an extrapolation of the thermoregulatory curve, is 8.4°C lower in selected (−28.6°C) than in control lines (−20.2°C). Thus, selection for high aerobic exercise performance, even though operating under thermally neutral conditions, has resulted in the evolution of increased cold tolerance, which, under natural conditions, could allow voles to inhabit colder environments. Further, the results of the current experiment support the assumptions of the aerobic capacity model of the evolution of endothermy.
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Affiliation(s)
- Clare Stawski
- Faculty of Biology and Earth Sciences, Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland.,Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Paweł Koteja
- Faculty of Biology and Earth Sciences, Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Edyta T Sadowska
- Faculty of Biology and Earth Sciences, Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
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Stawski C. Swindling cuckoos: hawk-like call tricks hosts. J Exp Biol 2017. [DOI: 10.1242/jeb.147694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Geiser F, Stawski C, Wacker CB, Nowack J. Phoenix from the Ashes: Fire, Torpor, and the Evolution of Mammalian Endothermy. Front Physiol 2017; 8:842. [PMID: 29163191 PMCID: PMC5673639 DOI: 10.3389/fphys.2017.00842] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/09/2017] [Indexed: 12/02/2022] Open
Affiliation(s)
- Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| | - Chris B Wacker
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia.,Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
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Stawski C. Polar regions and mountaintops are safe havens for caterpillars. J Exp Biol 2017. [DOI: 10.1242/jeb.147546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Stawski C. The little feathered ecosystem engineer. J Exp Biol 2017. [DOI: 10.1242/jeb.147397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Stawski C, Hume T, Körtner G, Currie SE, Nowack J, Geiser F. Post-fire recovery of torpor and activity patterns of a small mammal. Biol Lett 2017; 13:rsbl.2017.0036. [PMID: 28515330 DOI: 10.1098/rsbl.2017.0036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/25/2017] [Indexed: 11/12/2022] Open
Abstract
To cope with the post-fire challenges of decreased availability of food and shelter, brown antechinus (Antechinus stuartii), a small marsupial mammal, increase the use of energy-conserving torpor and reduce activity. However, it is not known how long it takes for animals to resume pre-fire torpor and activity patterns during the recovery of burnt habitat. Therefore, we tested the hypothesis that antechinus will adjust torpor use and activity after a fire depending on vegetation recovery. We simultaneously quantified torpor and activity patterns for female antechinus from three adjacent areas: (i) the area of a management burn 1 year post-fire, (ii) an area that was burned 2 years prior, and (iii) a control area. In comparison to shortly after the management burn, antechinus in all three groups displayed less frequent and less pronounced torpor while being more active. We provide the first evidence that only 1 year post-fire antechinus resume pre-fire torpor and activity patterns, probably in response to the return of herbaceous ground cover and foraging opportunities.
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
| | - Taylor Hume
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
| | - Gerhard Körtner
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
| | - Shannon E Currie
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia.,Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia.,Research Institute of Wildlife Ecology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna, Savoyenstrasse 1, 1160 Vienna, Austria
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
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Stawski C. Flexible activity behaviour aids survival in the Arctic. J Exp Biol 2017. [DOI: 10.1242/jeb.147272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Stawski C, Nowack J, Körtner G, Geiser F. A new cue for torpor induction: charcoal, ash and smoke. J Exp Biol 2017; 220:220-226. [DOI: 10.1242/jeb.146548] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/20/2016] [Indexed: 12/13/2022]
Abstract
ABSTRACT
Recent work has shown that the use of torpor for energy conservation increases after forest fires in heterothermic mammals, probably in response to the reduction of food. However, the specific environmental cues for this increased torpor expression remain unknown. It is possible that smoke and the novel substrate of charcoal and ash act as signals for an impending period of starvation requiring torpor. We therefore tested the hypothesis that the combined cues of smoke, a charcoal/ash substrate and food shortage will enhance torpor expression in a small forest-dwelling marsupial, the yellow-footed antechinus (Antechinus flavipes), because like other animals that live in fire-prone habitats they must effectively respond to fires to ensure survival. Activity and body temperature patterns of individuals in outdoor aviaries were measured under natural environmental conditions. All individuals were strictly nocturnal, but diurnal activity was observed shortly after smoke exposure. Overall, torpor in females was longer and deeper than that in males. Interestingly, while both males and females increased daily torpor duration during food restriction by >2-fold as anticipated, a combination of food restriction and smoke exposure on a charcoal/ash substrate further increased daily torpor duration by ∼2-fold in both sexes. These data show that this combination of cues for torpor induction is stronger than food shortage on its own. Our study provides significant new information on how a small forest-dwelling mammal responds to fire cues during and immediately after a fire and identifies a new, not previously recognised, regulatory mechanism for thermal biology in mammals.
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
- Research Institute of Wildlife Ecology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna, Savoyenstrasse 1, Vienna 1160, Austria
| | - Gerhard Körtner
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
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Currie SE, Stawski C, Geiser F. Cold-hearted bats: uncoupling of heart rate and metabolism during torpor at subzero temperatures. J Exp Biol 2017; 221:jeb.170894. [DOI: 10.1242/jeb.170894] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/02/2017] [Indexed: 01/22/2023]
Abstract
Many hibernating animals thermoregulate during torpor and defend their body temperature (Tb) below 10°C by an increase in metabolic rate. Above a critical temperature (Tcrit) animals usually thermoconform. We investigated the physiological responses above and below Tcrit for a small tree dwelling bat (Chalinolobus gouldii, ∼14 g) that is often exposed to subzero temperatures during winter. Through simultaneous measurement of heart rate (HR) and oxygen consumption (V̇O2) we show that the relationship between oxygen transport and cardiac function is substantially altered in thermoregulating torpid bats between 1 and -2°C, compared with thermoconforming torpid bats at mild ambient temperatures (Ta 5-20°C). Tcrit for this species was Ta 0.7±0.4°C, with a corresponding Tb of 1.8±1.2°C. Below Tcrit animals began to thermoregulate, indicated by a considerable but disproportionate increase in both HR and V̇O2. The maximum increase in HR was only 4-fold greater than the average thermoconforming minimum, compared to a 46-fold increase in V̇O2. The differential response of HR and V̇O2 to low Ta was reflected in a 15-fold increase in oxygen delivery per heart beat (cardiac oxygen pulse). During torpor at low Ta, thermoregulating bats maintained a relatively slow HR and compensated for increased metabolic demands by significantly increasing stroke volume and tissue oxygen extraction. Our study provides new information on the relationship between metabolism and HR in an unstudied physiological state that may occur frequently in the wild and can be extremely costly for heterothermic animals.
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Affiliation(s)
- Shannon E. Currie
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, 2351, NSW, Australia
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, 2351, NSW, Australia
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, 2351, NSW, Australia
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Matthews JK, Stawski C, Körtner G, Parker CA, Geiser F. Torpor and basking after a severe wildfire: mammalian survival strategies in a scorched landscape. J Comp Physiol B 2016; 187:385-393. [DOI: 10.1007/s00360-016-1039-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 09/14/2016] [Accepted: 09/30/2016] [Indexed: 11/24/2022]
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Nowack J, Delesalle M, Stawski C, Geiser F. Can hibernators sense and evade fires? Olfactory acuity and locomotor performance during deep torpor. Naturwissenschaften 2016; 103:73. [DOI: 10.1007/s00114-016-1396-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/27/2016] [Accepted: 07/29/2016] [Indexed: 10/21/2022]
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Sadowska ET, Stawski C, Rudolf A, Dheyongera G, Chrząścik KM, Baliga-Klimczyk K, Koteja P. Evolution of basal metabolic rate in bank voles from a multidirectional selection experiment. Proc Biol Sci 2016; 282:20150025. [PMID: 25876844 DOI: 10.1098/rspb.2015.0025] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A major theme in evolutionary and ecological physiology of terrestrial vertebrates encompasses the factors underlying the evolution of endothermy in birds and mammals and interspecific variation of basal metabolic rate (BMR). Here, we applied the experimental evolution approach and compared BMR in lines of a wild rodent, the bank vole (Myodes glareolus), selected for 11 generations for: high swim-induced aerobic metabolism (A), ability to maintain body mass on a low-quality herbivorous diet (H) and intensity of predatory behaviour towards crickets (P). Four replicate lines were maintained for each of the selection directions and an unselected control (C). In comparison to C lines, A lines achieved a 49% higher maximum rate of oxygen consumption during swimming, H lines lost 1.3 g less mass in the test with low-quality diet and P lines attacked crickets five times more frequently. BMR was significantly higher in A lines than in C or H lines (60.8, 56.6 and 54.4 ml O2 h(-1), respectively), and the values were intermediate in P lines (59.0 ml O2 h(-1)). Results of the selection experiment provide support for the hypothesis of a positive association between BMR and aerobic exercise performance, but not for the association of adaptation to herbivorous diet with either a high or low BMR.
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Affiliation(s)
- Edyta T Sadowska
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, Kraków 30-387, Poland
| | - Clare Stawski
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, Kraków 30-387, Poland
| | - Agata Rudolf
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, Kraków 30-387, Poland
| | - Geoffrey Dheyongera
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, Kraków 30-387, Poland
| | - Katarzyna M Chrząścik
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, Kraków 30-387, Poland
| | - Katarzyna Baliga-Klimczyk
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, Kraków 30-387, Poland
| | - Paweł Koteja
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, Kraków 30-387, Poland
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Abstract
Wildfires have increased in frequency and intensity worldwide with climate change as a main driving factor. While a number of studies have focused on population changes in regard to fires, there are essentially no quantitative data on behavioural and physiological adjustments that are vital for the persistence of individuals during and after fires. Here we show that brown antechinus, a small insectivorous marsupial mammal, (i) endured a prescribed fire in situ, (ii) remained in their scorched home range despite unburned areas nearby, and (iii) substantially increased post-fire torpor use and thus reduced foraging requirements and exposure to predators. Hence, torpor is a physiological adaptation that, although not quantified in this context previously, appears to play a key role in post-fire survival for this and other heterothermic species.
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
| | - Gerhard Körtner
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
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Abstract
Gould’s wattled bat (Chalinolobus gouldii) is one of only three native Australian mammals with an Australia-wide distribution. However, currently no data are available on the thermal physiology of free-ranging C. gouldii. Therefore, we aimed to quantify the effect of roost choice on daily skin temperature fluctuations during winter in C. gouldii living in an agricultural landscape in a temperate region. Ambient conditions consisted of long periods below 0°C and snow. Some individuals roosted high in dead branches whereas one individual roosted in a large cavity located low in a live tree. Torpor was employed on every day of the study period by all bats, with bouts lasting for over five days. The skin temperature of individuals in the dead branches tracked ambient temperature, with skin temperatures below 3°C on 67% of bat-days (lowest recorded –0.2°C). In contrast, the individual in the tree cavity maintained a larger skin-ambient temperature differential, likely influenced by the internal cavity temperature. Our study presents the lowest skin temperature recorded for a free-ranging Australian microbat and reveals that roost choice affects the thermal physiology of C. gouldii, ensuring survival during periods of cold weather and limited food supply.
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Stawski C, Valencak TG, Ruf T, Sadowska ET, Dheyongera G, Rudolf A, Maiti U, Koteja P. Effect of Selection for High Activity-Related Metabolism on Membrane Phospholipid Fatty Acid Composition in Bank Voles. Physiol Biochem Zool 2015; 88:668-79. [PMID: 26658414 DOI: 10.1086/683039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Endothermy, high basal metabolic rates (BMRs), and high locomotor-related metabolism were important steps in the evolution of mammals. It has been proposed that the composition of membrane phospholipid fatty acids plays an important role in energy metabolism and exercise muscle physiology. In particular, the membrane pacemaker theory of metabolism suggests that an increase in cell membrane fatty acid unsaturation would result in an increase in BMR. We aimed to determine whether membrane phospholipid fatty acid composition of heart, liver, and gastrocnemius muscles differed between lines of bank voles selected for high swim-induced aerobic metabolism-which also evolved an increased BMR-and unselected control lines. Proportions of fatty acids significantly differed among the organs: liver was the least unsaturated, whereas the gastrocnemius muscles were most unsaturated. However, fatty acid proportions of the heart and liver did not differ significantly between selected and control lines. In gastrocnemius muscles, significant differences between selection directions were found: compared to control lines, membranes of selected voles were richer in saturated C18:0 and unsaturated C18:2n-6 and C18:3n-3, whereas the pattern was reversed for saturated C16:0 and unsaturated C20:4n-6. Neither unsaturation index nor other combined indexes of fatty acid proportions differed between lines. Thus, our results do not support the membrane pacemaker hypothesis. However, the differences between selected and control lines in gastrocnemius muscles reflect chain lengths rather than number of double bonds and are probably related to differences in locomotor activity per se rather than to differences in the basal or routine metabolic rate.
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Affiliation(s)
- Clare Stawski
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland; 2Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse 1, 1160 Vienna, Austria
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Abstract
Prescribed fires for fuel reduction affect wildlife in several ways. We observed a marked increase in superb lyrebird (Menura novaehollandiae) numbers after a controlled burn in Guy Fawkes River National Park, New South Wales, in April and May 2014. The fire occurred during the winter breeding season; however, congregations of males were often seen together in the burnt landscape, indicating an opportunistic prioritisation of foraging. The low-intensity fire cleared brush and low-level vegetation, thus decreasing foraging effort and potentially attracting the species despite the need to seek mating partners. Controlled burns therefore have the potential to attract superb lyrebirds immediately after fire due to ease of movement and foraging effort.
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Stawski C, Koteja P, Sadowska ET, Jefimow M, Wojciechowski MS. Selection for high activity-related aerobic metabolism does not alter the capacity of non-shivering thermogenesis in bank voles. Comp Biochem Physiol A Mol Integr Physiol 2014; 180:51-6. [PMID: 25446149 DOI: 10.1016/j.cbpa.2014.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/31/2014] [Accepted: 11/02/2014] [Indexed: 12/22/2022]
Abstract
An intriguing question is how the capacity of non-shivering thermogenesis (NST)-a special mechanism supporting endothermic thermoregulation in mammals-is affected by selection for high exercise metabolism. It has been proposed that high NST could be a mechanism to compensate for a low basal production of heat. On the other hand, high basal or activity metabolism is associated with physiological characteristics such as high performance of the circulatory system, which are also required for achieving a high NST. Here we tested whether selection for high aerobic exercise performance, which correlates with an increased basal metabolic rate, led to a correlated evolution of maximum and facultative NST. Therefore, we measured the NST of bank voles, Myodes (= Clethrionomys) glareolus, from lines selected for 13-14 generations (n=46) for high aerobic metabolism achieved during swimming and from unselected, control lines (n=46). Open-flow respirometry was used to measure the rate of oxygen consumption (V(·)O2) in anesthetized bank voles injected with noradrenaline (NA). After adjusting for body mass, maximum NST (maximum V(·)O2 recorded after injection of NA) did not differ between the selected (2.38±0.08 mLO2min(-1)) and control lines (2.36±0.08 mLO2min(-1); P=0.891). Facultative NST (= maximum NST minus resting metabolic rate of anesthetized animals) did not differ between the selected (1.49±0.07 mLO2min(-1)) and control lines (1.50±0.07 mLO2min(-1); P=0.985), either. Therefore, our results suggest that NST capacity is not strongly linked to maximum activity-related aerobic metabolic rate.
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Affiliation(s)
- Clare Stawski
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, 30-387 Kraków, Poland.
| | - Paweł Koteja
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, 30-387 Kraków, Poland
| | - Edyta T Sadowska
- Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, 30-387 Kraków, Poland
| | - Małgorzata Jefimow
- Department of Animal Physiology, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
| | - Michał S Wojciechowski
- Department of Animal Physiology, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
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Affiliation(s)
- C. Stawski
- Institute of Environmental Sciences; Jagiellonian University; Kraków Poland
- Centre for Behavioural and Physiological Ecology, Zoology; University of New England; Armidale NSW Australia
| | - C. K. R. Willis
- Department of Biology and Centre for Forest Interdisciplinary Research; University of Winnipeg; Winnipeg Canada
| | - F. Geiser
- Centre for Behavioural and Physiological Ecology, Zoology; University of New England; Armidale NSW Australia
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Stawski C, Geiser F. Will temperature effects or phenotypic plasticity determine the thermal response of a heterothermic tropical bat to climate change? PLoS One 2012; 7:e40278. [PMID: 22802959 PMCID: PMC3389006 DOI: 10.1371/journal.pone.0040278] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 06/04/2012] [Indexed: 11/28/2022] Open
Abstract
The proportion of organisms exposed to warm conditions is predicted to increase during global warming. To better understand how bats might respond to climate change, we aimed to obtain the first data on how use of torpor, a crucial survival strategy of small bats, is affected by temperature in the tropics. Over two mild winters, tropical free-ranging bats (Nyctophilus bifax, 10 g, n = 13) used torpor on 95% of study days and were torpid for 33.5±18.8% of 113 days measured. Torpor duration was temperature-dependent and an increase in ambient temperature by the predicted 2°C for the 21st century would decrease the time in torpor to 21.8%. However, comparisons among Nyctophilus populations show that regional phenotypic plasticity attenuates temperature effects on torpor patterns. Our data suggest that heterothermy is important for energy budgeting of bats even under warm conditions and that flexible torpor use will enhance bats’ chance of survival during climate change.
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales, Australia.
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Stawski C. Capture and care of northern long-eared bats (Nyctophilus bifax) and seasonal changes in insect abundance. Aust Mammalogy 2012. [DOI: 10.1071/am11043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Seasonal capture rates of insectivorous subtropical and tropical Australian northern long-eared bats (Nyctophilus bifax) (Chiroptera: Vespertilionidae) in relation to ambient temperature and insect abundance were examined. Insect abundance varied seasonally in a subtropical region and also between subtropical and tropical habitats during winter, and decreased as nightly ambient temperature decreased. While capture rates of N. bifax were not affected by ambient temperatures and insect abundance, most captures occurred within one hour after sunset, which is generally the time of highest activity levels in microbats. Methods of care of N. bifax in captivity are also reported. N. bifax adapted well to short-term captivity (up to 14 days) and readily accepted mealworms as a food source.
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Geiser F, Stawski C. Hibernation and torpor in tropical and subtropical bats in relation to energetics, extinctions, and the evolution of endothermy. Integr Comp Biol 2011; 51:337-48. [PMID: 21700575 DOI: 10.1093/icb/icr042] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Torpor, the most effective means of energy conservation available to endotherms, is still widely viewed as a specific adaptation in a few high-latitude, cold-climate endotherms with no adaptive function in warm regions. Nevertheless, a growing number of diverse terrestrial mammals and birds from low latitudes (0-30°), including species from tropical and subtropical regions, are heterothermic and employ torpor. Use of torpor is especially important for bats because they are small, expend large amounts of energy when active, rely on a fluctuating food supply, and have only a limited capacity for storage of fat. Patterns of torpor in tropical/subtropical bats are highly variable, but short bouts of torpor with relatively high body temperatures (T(b)) are most common. Hibernation (a sequence of multiday bouts of torpor) has been reported for free-ranging subtropical tree-dwelling vespertilionids, cave-dwelling hipposiderids, and house-dwelling molossids. The observed range of minimum T(b) is ∼6-30 °C, and the reduction of energy expenditure through the use of torpor, in comparison to normothermic values, ranges from 50 to 99%. Overall, torpor in the tropics/subtropics has been reported for 10 out of the currently recognized 18 bat families, which contain 1079 species, or 96.7% of all bats. Although it is unlikely that all of these are heterothermic, the large majority probably will be. Frequent use of torpor, including hibernation in diverse groups of tropical/subtropical bats, suggests that heterothermy is an ancestral chiropteran trait. Although data especially from the field are still scarce, it is likely that torpor, highly effective in reducing requirements for energy and water even under warm conditions, plays a crucial role in the long-term survival of the majority of small tropical and subtropical bats. Discovering how bats achieve this provides numerous opportunities for exiting new research.
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Affiliation(s)
- Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale NSW 2351, Australia.
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Stawski C, Geiser F. Do season and distribution affect thermal energetics of a hibernating bat endemic to the tropics and subtropics? Am J Physiol Regul Integr Comp Physiol 2011; 301:R542-7. [PMID: 21632847 DOI: 10.1152/ajpregu.00792.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although many tropical and subtropical areas experience pronounced seasonal changes in weather and food availability, few studies have examined and none have compared the thermal physiology and energetics of a hibernating mammal that is restricted to these regions. We quantified thermal energetics of northern long-eared bats (Nyctophilus bifax; body mass ∼10 g) during summer, winter, and spring from a subtropical habitat, and also during winter from a tropical habitat, to determine how N. bifax cope with climate and seasonal changes in weather. We captured bats in the wild and measured metabolic rates via open-flow respirometry. The basal metabolic rate of subtropical bats at an ambient temperature (T(a)) of 32.6 ± 0.7°C was 1.28 ± 0.06 ml O(2)·g(-1)·h(-1) during both summer and winter, similar to other species of Nyctophilus. Resting metabolic rates below the thermoneutral zone increased similarly with decreasing T(a) during all seasons and in both regions. All individuals showed a high proclivity to enter torpor at T(a) values below the thermoneutral zone. Metabolic rates in torpid thermoconforming bats fell with T(a) and body temperature, and mean minimum metabolic rates during torpor were similar during all seasons and in both regions and as predicted from body mass in temperate zone hibernators. At very low T(a), torpid N. bifax thermoregulated, and this threshold T(a) differed significantly between subtropical (T(a) = 3.5 ± 0.3°C) and tropical (T(a) = 6.7 ± 0.7°C) individuals, but not between seasons. Our data show that thermal energetics of N. bifax do not vary seasonally and in many aspects are similar in tropical and subtropical bats; however, torpid individuals from the subtropics allow body temperature to fall to significantly lower values than those from the tropics.
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Affiliation(s)
- Clare Stawski
- Center for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales, Australia.
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Geiser F, Stawski C, Bondarenco A, Pavey CR. Torpor and activity in a free-ranging tropical bat: implications for the distribution and conservation of mammals? Naturwissenschaften 2011; 98:447-52. [DOI: 10.1007/s00114-011-0779-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 11/29/2022]
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