101
|
Nespolo RF, Mejias C, Bozinovic F. Isometric scaling of hibernation: when trees do not let the forest be seen. Proc Biol Sci 2022; 289:20221719. [PMID: 36476001 PMCID: PMC9554729 DOI: 10.1098/rspb.2022.1719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Roberto F. Nespolo
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Los Ríos, Chile,Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Los Ríos, Chile,Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, Santiago, Chile,Millennium Nucleus of Patagonian Limit of Life (LiLi) and iBio Millennium Institute, Santiago, Chile
| | - Carlos Mejias
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Los Ríos, Chile,Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Los Ríos, Chile,Magister en Ecología Aplicada, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Los Ríos, Chile
| | - Francisco Bozinovic
- Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, Santiago, Chile,Departamento de Ecología Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| |
Collapse
|
102
|
Henke‐von der Malsburg J, Fichtel C, Kappeler PM. Retaining memory after hibernation: Performance varies independently of activity levels in wild grey mouse lemurs. Ethology 2022. [DOI: 10.1111/eth.13337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Johanna Henke‐von der Malsburg
- Behavioral Ecology and Sociobiology Unit German Primate Center, Leibniz Institute for Primatology Göttingen Germany
- Leibniz ScienceCampus ‘Primate Cognition’ Göttingen Germany
- Department of Sociobiology/Anthropology Johann‐Friedrich‐Blumenbach Institute of Zoology and Anthropology, Kellnerweg 6, 37077 Göttingen, Georg‐August‐University Göttingen Göttingen Germany
- Technological Primates Research Group Max‐Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Claudia Fichtel
- Behavioral Ecology and Sociobiology Unit German Primate Center, Leibniz Institute for Primatology Göttingen Germany
- Leibniz ScienceCampus ‘Primate Cognition’ Göttingen Germany
| | - Peter M. Kappeler
- Behavioral Ecology and Sociobiology Unit German Primate Center, Leibniz Institute for Primatology Göttingen Germany
- Department of Sociobiology/Anthropology Johann‐Friedrich‐Blumenbach Institute of Zoology and Anthropology, Kellnerweg 6, 37077 Göttingen, Georg‐August‐University Göttingen Göttingen Germany
| |
Collapse
|
103
|
Ruf T, Bieber C. Why hibernate? Predator avoidance in the edible dormouse. MAMMAL RES 2022; 68:1-11. [PMID: 36624745 PMCID: PMC9816287 DOI: 10.1007/s13364-022-00652-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/29/2022] [Indexed: 01/12/2023]
Abstract
We address the question of ultimate selective advantages of hibernation. Biologists generally seem to accept the notion that multiday torpor is primarily a response to adverse environmental conditions, namely cold climate and low food abundance. We closely examine hibernation, and its summer equivalent estivation, in the edible dormouse, Glis glis. We conclude that in this species, hibernation is not primarily driven by poor conditions. Dormice enter torpor with fat reserves in years that are unfavourable for reproduction but provide ample food supply for animals to sustain themselves and even gain body energy reserves. While staying in hibernacula below ground, hibernators have much higher chances of survival than during the active season. We think that dormice enter prolonged torpor predominantly to avoid predation, mainly nocturnal owls. Because estivation in summer is immediately followed by hibernation, this strategy requires a good body condition in terms of fat reserves. As dormice age, they encounter fewer occasions to reproduce when calorie-rich seeds are available late in the year, and phase advance the hibernation season. By early emergence from hibernation, the best territories can be occupied and the number of mates maximised. However, this advantage comes at the cost of increased predation pressure that is maximal in spring. We argue the predator avoidance is generally one of the primary reasons for hibernation, as increased perceived predation pressure leads to an enhanced torpor use. The edible dormouse may be just an example where this behaviour becomes most obvious, on the population level and across large areas.
Collapse
Affiliation(s)
- Thomas Ruf
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse 1, 1160 Vienna, Austria
| | - Claudia Bieber
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse 1, 1160 Vienna, Austria
| |
Collapse
|
104
|
Noakes MJ, Przybylska-Piech AS, Wojciechowski MS, Jefimow M. Is torpor a water conservation strategy? Heterothermic responses to acute water and food deprivation are repeatable among individuals of Phodopus sungorus. J Therm Biol 2022; 109:103321. [DOI: 10.1016/j.jtherbio.2022.103321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/01/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022]
|
105
|
Ingelson-Filpula WA, Cheng H, Eaton L, Pamenter ME, Storey KB. Small RNA sequencing in hypoxic naked mole-rat hearts suggests microRNA regulation of RNA- and translation-related processes. FEBS Lett 2022; 596:2821-2833. [PMID: 36120811 DOI: 10.1002/1873-3468.14499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 11/09/2022]
Abstract
The naked mole-rat (Heterocephalus glaber) regularly endures intermittent periods of hypoxia in its burrows, surviving in part due to metabolic rate depression (MRD)-a strategy of conserving cellular resources by downregulating nonessential gene expression and reorganizing cellular processes. MicroRNA (miRNA) are short, noncoding RNAs already implicated for their roles in numerous models of extreme environmental stress; given their rapid, reversible nature, they are ideal for implementing MRD. We performed small RNA sequencing on cardiac tissue from normoxic vs. 24 h hypoxic naked mole-rats, and used bioinformatics to predict eighteen miRNAs which may be differentially regulated during hypoxia. Gene Ontology and KEGG pathway mapping further suggest these miRNAs play roles in largely translation-related functions, including RNA processing and catabolism.
Collapse
Affiliation(s)
- W Aline Ingelson-Filpula
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
| | - Hang Cheng
- Biology Department, University of Ottawa, Marie-Curie Pvt, Ottawa, Ontario, K1N 9A7, Canada
| | - Liam Eaton
- Biology Department, University of Ottawa, Marie-Curie Pvt, Ottawa, Ontario, K1N 9A7, Canada
| | - Matthew E Pamenter
- Biology Department, University of Ottawa, Marie-Curie Pvt, Ottawa, Ontario, K1N 9A7, Canada.,Brain and Mind Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Kenneth B Storey
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
| |
Collapse
|
106
|
Swanson DL, Vézina F, McKechnie AE, Nord A. Editorial: Avian behavioral and physiological responses to challenging thermal environments and extreme weather events. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1034659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
107
|
Nemcova M, Seidlova V, Zukal J, Dundarova H, Zukalova K, Pikula J. Performance of bat-derived macrophages at different temperatures. Front Vet Sci 2022; 9:978756. [PMID: 36157196 PMCID: PMC9500541 DOI: 10.3389/fvets.2022.978756] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Heterothermy, as a temperature-dependent physiological continuum, may affect host-pathogen interactions through modulation of immune responses. Here, we evaluated proliferation and functional performance of a macrophage cell line established from the greater mouse-eared (Myotis myotis) bat at 8, 17.5, and 37°C to simulate body temperatures during hibernation, daily torpor and euthermia. Macrophages were also frozen to -20°C and then examined for their ability to proliferate in the immediate post-thaw period. We show that bat macrophages can proliferate at lower temperatures, though their growth rate is significantly slower than at 37°C. The cells differed in their shape, size and ability to attach to the plate surface at both lower temperatures, being spheroidal and free in suspension at 8°C and epithelial-like, spindle-shaped and/or spheroidal at 17.5°C. While phagocytosis at temperatures of 8 and 17.5°C amounted to 85.8 and 83.1% of the activity observed at 37°C, respectively, full phagocytic activity was restored within minutes of translocation into a higher temperature. Bat-derived macrophages were also able to withstand temperatures of -20°C in a cryoprotectant-free cultivation medium and, in the immediate post-thaw period, became viable and were able to proliferate. Our in vitro data enhance understanding of macrophage biology.
Collapse
Affiliation(s)
- Monika Nemcova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
| | - Veronika Seidlova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia
| | - Jan Zukal
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia
- Department of Botany and Zoology, Masaryk University, Brno, Czechia
| | - Heliana Dundarova
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Katerina Zukalova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
| | - Jiri Pikula
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences Brno, Brno, Czechia
- CEITEC-Central European Institute of Technology, University of Veterinary Sciences Brno, Brno, Czechia
| |
Collapse
|
108
|
High level of daily heterothermy in desert gerbils. JOURNAL OF TROPICAL ECOLOGY 2022. [DOI: 10.1017/s0266467422000360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract
Daily heterothermy is a strategy employed by endothermic birds and mammals to reduce their energetic costs by lowering their metabolic rate. We recorded nocturnal and diurnal rectal temperatures in three Moroccan Gerbillus rodent species to determine the level of heterothermy. A decrease in body temperature from night to day was observed by an average (±SD) of 8.7 (±4.2) in G. gerbillus, 11.1 (±3.0) in G. amoenus, and 7.7 (±3.3)°C in G. sp.1, the first records of heterothermy in the three species. The findings support a prediction that daily heterothermy is found in mammals from arid and semi-arid regions, contributing to further knowledge of thermoregulation in desert rodents.
Collapse
|
109
|
Charlanne LM, Vetter S, Einwaller J, Painer J, Gilbert C, Giroud S. Sticking Together: Energetic Consequences of Huddling Behavior in Hibernating Juvenile Garden Dormice. Physiol Biochem Zool 2022; 95:400-415. [PMID: 35930826 DOI: 10.1086/721184] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
AbstractHibernation, or multiday torpor, allows individuals to save energy via substantial reductions of metabolism and body temperature but is regularly interrupted by euthermic phases called arousals. Social thermoregulation, or "huddling," can act in synergy with torpor in reducing individuals' energy and heat losses. In the wild, the garden dormouse (Eliomys quercinus) combines both strategies, which are crucial for winter survival of juveniles with limited prehibernation body fat reserves. We investigated via thermographic and temperature measurements (i) the energetic impact of huddling during an arousal from deep torpor, (ii) the dynamics of huddling behavior during hibernation, and (iii) its consequences during the entire winter in juvenile garden dormice. Thermographic images revealed a significant effect of huddling on torpor energetics, as it reduced heat exchange and mass loss by two-thirds in huddling versus single individuals during arousal. Our investigation of the dynamics of huddling further revealed a "random-like mechanistic" behavior during winter hibernation, as arousals from torpor were not always initiated by the same individuals. Animals took turns in initiating rewarming within a group, and the individual with highest body temperature during arousal entered into torpor later than the others within the huddle. The animals share both costs and benefits of huddling during arousals, without any energetic benefit of huddling over the entire winter on an individual level. We conclude that the dynamics of social thermoregulation during hibernation seems to counterbalance its benefit of reducing energetic costs associated against the energy-demanding process of rewarming from torpor.
Collapse
|
110
|
Miao W, Han Y, Yang Y, Hao Z, An N, Chen J, Zhang Z, Gao X, Storey KB, Chang H, Wang S. Dynamic Changes in Colonic Structure and Protein Expression Suggest Regulatory Mechanisms of Colonic Barrier Function in Torpor-Arousal Cycles of the Daurian Ground Squirrel. Int J Mol Sci 2022; 23:ijms23169026. [PMID: 36012293 PMCID: PMC9409258 DOI: 10.3390/ijms23169026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/23/2022] [Accepted: 08/10/2022] [Indexed: 12/22/2022] Open
Abstract
Background: Both pathological conditions and hibernation can affect the barrier function of small intestine mucosa. However, the effect of hibernation on the barrier function of colonic mucosa remains unclear. Methods: We investigated morphological changes in colonic mucosa, the concentrations of specific proteins and molecules, and the enzymatic activity of diamine oxidase (DAO), in serum and colonic tissue; the expression of tight junction proteins and mucin, and the changes in inflammatory, farnesoid X receptor (FXR)–small heterodimer partner (SHP), and apoptosis-related molecules that could play a role in gut permeability changes in Daurian ground squirrels in summer active (SA), late torpor (LT), and interbout arousal (IBA) periods. Results: The results show that hibernation reduced the thickness of the colonic mucosa and the depth of the crypt, decreased the number of goblet cells (GCs), and damaged the structure of some microvilli. The concentrations of proteins and molecules, and the enzymatic activity of DAO, were all increased in the serum and colon, and the localization of tight junction proteins and mucin in the colonic mucosa were altered (compensatory response). Although the ground squirrels ate during the interbout arousal period, the changes remained similar to the response to torpor. Inflammation, apoptosis–anti-apoptosis, and FXR–SHP signaling may be involved in the possible changes in intestinal gut permeability during the torpor–arousal cycle in Daurian ground squirrels. In addition, periodic interbout arousal may play an inflammation-correcting role during the long hibernation season of Daurian ground squirrels.
Collapse
Affiliation(s)
- Weilan Miao
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi’an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Yuting Han
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Yingyu Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Ziwei Hao
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Ning An
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Jiayu Chen
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Ziwen Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Xuli Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
| | - Kenneth B. Storey
- Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Hui Chang
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi’an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
- Correspondence: (H.C.); (S.W.); Tel.: +86-29-88303935 (H.C.)
| | - Shiwei Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (College of Life Sciences, Northwest University), Ministry of Education, 229# North Taibai Road, Xi’an 710069, China
- Correspondence: (H.C.); (S.W.); Tel.: +86-29-88303935 (H.C.)
| |
Collapse
|
111
|
Harding CD, Yovel Y, Peirson SN, Hackett TD, Vyazovskiy VV. Re-examining extreme sleep duration in bats: implications for sleep phylogeny, ecology, and function. Sleep 2022; 45:zsac064. [PMID: 35279722 PMCID: PMC9366634 DOI: 10.1093/sleep/zsac064] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/17/2022] [Indexed: 11/23/2022] Open
Abstract
Bats, quoted as sleeping for up to 20 h a day, are an often used example of extreme sleep duration amongst mammals. Given that duration has historically been one of the primary metrics featured in comparative studies of sleep, it is important that species specific sleep durations are well founded. Here, we re-examined the evidence for the characterization of bats as extreme sleepers and discuss whether it provides a useful representation of the sleep behavior of Chiroptera. Although there are a wealth of activity data to suggest that the diurnal cycle of bats is dominated by rest, estimates of sleep time generated from electrophysiological analyses suggest considerable interspecific variation, ranging from 83% to a more moderate 61% of the 24 h day spent asleep. Temperature-dependent changes in the duration and electroencephalographic profile of sleep suggest that bats represent a unique model for investigating the relationship between sleep and torpor. Further sources of intra-specific variation in sleep duration, including the impact of artificial laboratory environments and sleep intensity, remain unexplored. Future studies conducted in naturalistic environments, using larger sample sizes and relying on a pre-determined set of defining criteria will undoubtedly provide novel insights into sleep in bats and other species.
Collapse
Affiliation(s)
- Christian D Harding
- Department of Physiology Anatomy and Genetics, Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
- The Kavli Institute for Nanoscience Discovery, Oxford, UK
| | - Yossi Yovel
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Stuart N Peirson
- The Kavli Institute for Nanoscience Discovery, Oxford, UK
- Nuffield Department of Clinical Neurosciences, Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
| | | | - Vladyslav V Vyazovskiy
- Department of Physiology Anatomy and Genetics, Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
- The Kavli Institute for Nanoscience Discovery, Oxford, UK
| |
Collapse
|
112
|
Sullivan IR, Adams DM, Greville LJS, Faure PA, Wilkinson GS. Big brown bats experience slower epigenetic ageing during hibernation. Proc Biol Sci 2022; 289:20220635. [PMID: 35946154 PMCID: PMC9364000 DOI: 10.1098/rspb.2022.0635] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Comparative analyses of bats indicate that hibernation is associated with increased longevity among species. However, it is not yet known if hibernation affects biological ageing of individuals. Here, we use DNA methylation (DNAm) as an epigenetic biomarker of ageing to determine the effect of hibernation on the big brown bat, Eptesicus fuscus. First, we compare epigenetic age, as predicted by a multi-species epigenetic clock, between hibernating and non-hibernating animals and find that hibernation is associated with epigenetic age. Second, we identify genomic sites that exhibit hibernation-associated change in DNAm, independent of age, by comparing samples taken from the same individual in hibernating and active seasons. This paired comparison identified over 3000 differentially methylated positions (DMPs) in the genome. Genome-wide association comparisons to tissue-specific functional elements reveals that DMPs with elevated DNAm during winter occur at sites enriched for quiescent chromatin states, whereas DMPs with reduced DNAm during winter occur at sites enriched for transcription enhancers. Furthermore, genes nearest DMPs are involved in regulation of metabolic processes and innate immunity. Finally, significant overlap exists between genes nearest hibernation DMPs and genes nearest previously identified longevity DMPs. Taken together, these results are consistent with hibernation influencing ageing and longevity in bats.
Collapse
Affiliation(s)
- Isabel R. Sullivan
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Danielle M. Adams
- Department of Biology, University of Maryland, College Park, MD 20742, USA,Department of Biological Sciences, Towson University, Towson, MD 21252, USA
| | - Lucas J. S. Greville
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1,Department of Biology, University of Waterloo, Waterloo, ON, Canada N3 L 3G1
| | - Paul A. Faure
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
| | | |
Collapse
|
113
|
Flexible energy-saving strategies in female temperate-zone bats. J Comp Physiol B 2022; 192:805-814. [PMID: 35939092 PMCID: PMC9550788 DOI: 10.1007/s00360-022-01452-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 07/06/2022] [Accepted: 07/19/2022] [Indexed: 12/02/2022]
Abstract
Torpor is characterized by an extreme reduction in metabolism and a common energy-saving strategy of heterothermic animals. Torpor is often associated with cold temperatures, but in the last decades, more diverse and flexible forms of torpor have been described. For example, tropical bat species maintain a low metabolism and heart rate at high ambient and body temperatures. We investigated whether bats (Nyctalus noctula) from the cooler temperate European regions also show this form of torpor with metabolic inhibition at high body temperatures, and whether this would be as pronounced in reproductive as in non-reproductive bats. We simultaneously measured metabolic rate, heart rate, and skin temperature in non-reproductive and pregnant females at a range of ambient temperatures. We found that they can decouple metabolic rate and heart rate from body temperature: they maintained an extremely low metabolism and heart rate when exposed to ambient temperatures changing from 0 to 32.5 °C, irrespective of reproductive status. When we simulated natural temperature conditions, all non-reproductive bats used torpor throughout the experiment. Pregnant bats used variable strategies from torpor, to maintaining normothermy, or a combination of both. Even a short torpor bout during the day saved up to 33% of the bats' total energy expenditure. Especially at higher temperatures, heart rate was a much better predictor of metabolic rate than skin temperature. We suggest that the capability to flexibly save energy across a range of ambient temperatures within and between reproductive states may be an important ability of these bats and possibly other temperate-zone heterotherms.
Collapse
|
114
|
Zhou J, Wang M, Yi X. Alteration of Gut Microbiota of a Food-Storing Hibernator, Siberian Chipmunk Tamias sibiricus. MICROBIAL ECOLOGY 2022; 84:603-612. [PMID: 34562129 DOI: 10.1007/s00248-021-01877-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 09/17/2021] [Indexed: 06/13/2023]
Abstract
Hibernation represents a state of fasting because hibernators cease eating in the torpid periods. Therefore, food deprivation during hibernation is expected to modify the gut microbiota of host. However, there are few reports of gut microbiota in food-storing hibernators that feed during the interbout arousals. Here we collected fecal samples of Siberian chipmunk T. sibiricus to character and examine changes in the gut microbiota at various stages relative to hibernation: pre-hibernation, early-hibernation, mid-hibernation, late-hibernation, and post-hibernation. Compared to the pre-hibernation state, alpha-diversity of gut microbiota was significantly increased during the interbout arousal periods. In addition, beta-diversity of the fecal communities from pre-hibernation and interbout arousal periods grouped together, and post-hibernation gut microbiota resembled the counterpart at late-hibernation. Hibernation significantly decreased the relative abundance of Firmicutes but increased Bacteroidetes, reflecting a shift of microbiota toward taxa in favor of host-derived substrates. The increased abundance of Ruminococcaceae_UCG-014, Lactobacillus, and Christensenellaceae_R-7_group in gut microbiota may help the chipmunks reduce intestinal inflammation and then maintain healthy bowel during hibernation. KEGG pathway indicated that hibernation altered the metabolic function of gut microflora of T. sibiricus. Our study provides evidence that the gut microbiota of food-storing hibernators, despite feeding during the interbout arousals, shows similar response to hibernation that has well documented in fat-storing counterparts, suggesting the potential for a core gut microbiota during hibernation of mammals. Importantly, these results will broaden our understanding of the effects of hibernation on gut microbiota of mammal hibernators.
Collapse
Affiliation(s)
- Jing Zhou
- College of Life Sciences, Qufu Normal University, Qufu, 273165, China
| | - Minghui Wang
- College of Life Sciences, Qufu Normal University, Qufu, 273165, China
| | - Xianfeng Yi
- College of Life Sciences, Qufu Normal University, Qufu, 273165, China.
| |
Collapse
|
115
|
Pani P, Bal NC. Avian adjustments to cold and non-shivering thermogenesis: whats, wheres and hows. Biol Rev Camb Philos Soc 2022; 97:2106-2126. [PMID: 35899483 DOI: 10.1111/brv.12885] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/28/2022]
Abstract
Avian cold adaptation is hallmarked by innovative strategies of both heat conservation and thermogenesis. While minimizing heat loss can reduce the thermogenic demands of body temperature maintenance, it cannot eliminate the requirement for thermogenesis. Shivering and non-shivering thermogenesis (NST) are the two synergistic mechanisms contributing to endothermy. Birds are of particular interest in studies of NST as they lack brown adipose tissue (BAT), the major organ of NST in mammals. Critical analysis of the existing literature on avian strategies of cold adaptation suggests that skeletal muscle is the principal site of NST. Despite recent progress, isolating the mechanisms involved in avian muscle NST has been difficult as shivering and NST co-exist with its primary locomotory function. Herein, we re-evaluate various proposed molecular bases of avian skeletal muscle NST. Experimental evidence suggests that sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA) and ryanodine receptor 1 (RyR1) are key in avian muscle NST, through their mediation of futile Ca2+ cycling and thermogenesis. More recent studies have shown that SERCA regulation by sarcolipin (SLN) facilitates muscle NST in mammals; however, its role in birds is unclear. Ca2+ signalling in the muscle seems to be common to contraction, shivering and NST, but elucidating its roles will require more precise measurement of local Ca2+ levels inside avian myofibres. The endocrine control of avian muscle NST is still poorly defined. A better understanding of the mechanistic details of avian muscle NST will provide insights into the roles of these processes in regulatory thermogenesis, which could further inform our understanding of the evolution of endothermy among vertebrates.
Collapse
Affiliation(s)
- Punyadhara Pani
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India
| | - Naresh C Bal
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India
| |
Collapse
|
116
|
Barratt AE, Gonsalves L, Turbill C. Winter torpor and activity patterns of a fishing bat ( Myotis macropus) in a mild climate. J Mammal 2022. [DOI: 10.1093/jmammal/gyac061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Small insectivorous bats often enter a state of torpor, a controlled, reversible decrease in body temperature and metabolic rate. Torpor provides substantial energy savings and is used more extensively during periods of low temperature and reduced prey availability. We studied torpor use and activity of a small (10.1 ± 0.4 g) fishing bat, Myotis macropus, during winter in a mild climate in Australia. We predicted that the thermal stability of water would make foraging opportunities in winter more productive and consistent in a riparian habitat compared to a woodland habitat, and therefore, fishing bats would use torpor less than expected during winter compared to other bats. Using temperature-sensitive radio transmitters, we recorded the skin temperature of 12 adult (6 M, 6 F) bats over 161 bat-days (13.4 ± 5.4 days per bat) during Austral winter (late May to August), when daily air temperature averaged 6.2–18.2°C. Bats used torpor every day, with bouts lasting a median of 21.3 h and up to 144.6 h. Multiday torpor bouts were more common in females than males. Arousals occurred just after sunset and lasted 3.5 ± 2.9 h. Arousals tended to be longer in males than females and to occur on warmer evenings, suggesting some winter foraging and perhaps male harem territoriality or other mating-related activity was occurring. The extensive use of torpor by M. macropus during relatively mild winter conditions when food is likely available suggests torpor might function to minimize the risks of mortality caused by activity and to increase body condition for the upcoming breeding season.
Collapse
Affiliation(s)
- Alice E Barratt
- Hawkesbury Institute for the Environment and School of Science, Western Sydney University, Hawkesbury Campus , Richmond, New South Wales 2753 , Australia
| | - Leroy Gonsalves
- Forest Science Unit, New South Wales Department of Primary Industries , Parramatta, New South Wales 2150 , Australia
| | - Christopher Turbill
- Hawkesbury Institute for the Environment and School of Science, Western Sydney University, Hawkesbury Campus , Richmond, New South Wales 2753 , Australia
| |
Collapse
|
117
|
Melcore I, Bertolino S, Boratyński Z. Variation of rodents’ body temperature across elevation in Alps. Physiol Biochem Zool 2022; 95:517-524. [DOI: 10.1086/721477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
118
|
Siutz C, Nemeth M, Quint R, Wagner KH, Millesi E. PUFA changes in white adipose tissue during hibernation in common hamsters. Physiol Biochem Zool 2022; 95:525-535. [DOI: 10.1086/721444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
119
|
Ruf T, Giroud S, Geiser F. Hypothesis and Theory: A Two-Process Model of Torpor-Arousal Regulation in Hibernators. Front Physiol 2022; 13:901270. [PMID: 35812322 PMCID: PMC9266152 DOI: 10.3389/fphys.2022.901270] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
Hibernating mammals drastically lower their metabolic rate (MR) and body temperature (Tb) for up to several weeks, but regularly rewarm and stay euthermic for brief periods. It has been hypothesized that the necessity for rewarming is due to the accumulation or depletion of metabolites, or the accrual of cellular damage that can be eliminated only in the euthermic state. Recent evidence for significant inverse relationships between the duration of torpor bouts (TBD) and MR in torpor strongly supports this hypothesis. We developed a new mathematical model that simulates hibernation patterns. The model involves an hourglass process H (Hibernation) representing the depletion/accumulation of a crucial enzyme/metabolite, and a threshold process Hthr. Arousal, modelled as a logistic process, is initiated once the exponentially declining process H reaches Hthr. We show that this model can predict several phenomena observed in hibernating mammals, namely the linear relationship between TMR and TBD, effects of ambient temperature on TBD, the modulation of torpor depth and duration within the hibernation season, (if process Hthr undergoes seasonal changes). The model does not need but allows for circadian cycles in the threshold T, which lead to arousals occurring predominantly at certain circadian phases, another phenomenon that has been observed in certain hibernators. It does not however, require circadian rhythms in Tb or MR during torpor. We argue that a two-process regulation of torpor-arousal cycles has several adaptive advantages, such as an easy adjustment of TBD to environmental conditions as well as to energy reserves and, for species that continue to forage, entrainment to the light-dark cycle.
Collapse
Affiliation(s)
- Thomas Ruf
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Vienna, Austria
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
- *Correspondence: Thomas Ruf,
| | - Sylvain Giroud
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| |
Collapse
|
120
|
Rudolf MF, Wilson EC, Pauli JN. Anomalous snow events increase mortality for a winter-adapted species. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2022-0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Winter is a costly time for animals, requiring individuals to adapt to increased energetic costs, and reduced resources. Porcupines (Erethizon dorsatum Linnaeus, 1758) confront winter by storing and catabolizing somatic stores. Increasing temperatures and attenuated snow conditions due to climate change increase porcupine survival, but impacts of greater weather variability has not been explored. In April of 2018, an anomalously heavy and late snowstorm occurred at our long-term study site in central Wisconsin followed by multiple mortalities among adult porcupines. We assessed cause of mortality and determined nutritional condition by extracting bone marrow, and quantifying lipid content. Porcupines that died following the snow event had lower fat stores than the fall 2019 group, and likely died of starvation. We estimated survival of female porcupines during the winters 2012 & 2015-2018 to assess the effects of snow conditions and nutritional condition on survival. Survival declined with increased snow depth but increased with improved nutritional condition. The mass starvation event we observed in 2018 appeared to have resulted from deep snow increasing locomotive costs and reducing nutritional condition. As climate change increases the frequency of extreme weather events, including extreme snowfalls, we predict that the frequency of such clustered mortalities will increase.
Collapse
Affiliation(s)
- Michaela Floren Rudolf
- University of Wisconsin-Madison, Department of Forest and Wildlife Ecology, Madison, Wisconsin, United States
| | - Evan Costello Wilson
- University of Wisconsin-Madison, Department of Forest & Wildlife Ecology, Madison, Wisconsin, United States
- University of Michigan, 1259, School of Environment and Sustainability, Ann Arbor, Michigan, United States,
| | - Jonathan N Pauli
- University of Wisconsin-Madison, Department of Forest and Wildlife Ecology, Madison, Wisconsin, United States
| |
Collapse
|
121
|
Blanco MB, Greene LK, Ellsaesser LN, Schopler B, Davison M, Ostrowski C, Klopfer PH, Fietz J, Ehmke EE. Of fruits and fats: high-sugar diets restore fatty acid profiles in the white adipose tissue of captive dwarf lemurs. Proc Biol Sci 2022; 289:20220598. [PMID: 35703045 PMCID: PMC9198768 DOI: 10.1098/rspb.2022.0598] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Fat-storing hibernators rely on fatty acids from white adipose tissue (WAT) as an energy source to sustain hibernation. Whereas arctic and temperate hibernators preferentially recruit dietary polyunsaturated fatty acids (PUFAs), tropical hibernators can rely on monounsaturated fatty acids that produce fewer lipid peroxides during oxidation. Nevertheless, compositional data on WAT from tropical hibernators are scant and questions remain regarding fat recruitment and metabolism under different environmental conditions. We analyse fatty acid profiles from the WAT of captive dwarf lemurs (Cheirogaleus medius) subjected to high-sugar or high-fat diets during fattening and cold or warm conditions during hibernation. Dwarf lemurs fed high-sugar (compared to high-fat) diets displayed WAT profiles more comparable to wild lemurs that fatten on fruits and better depleted their fat reserves during hibernation. One PUFA, linoleic acid, remained elevated before hibernation, potentially lingering from the diets provisioned prior to fattening. That dwarf lemurs preferentially recruit the PUFA linoleic acid from diets that are naturally low in availability could explain the discrepancy between captive and wild lemurs' WAT. While demonstrating that minor dietary changes can produce major changes in seasonal fat deposition and depletion, our results highlight the complex role for PUFA metabolism in the ecology of tropical hibernators.
Collapse
Affiliation(s)
- M. B. Blanco
- Duke Lemur Center, Durham, NC, USA,Department of Biology, Duke University, Durham, NC, USA
| | - L. K. Greene
- Duke Lemur Center, Durham, NC, USA,Department of Biology, Duke University, Durham, NC, USA
| | | | | | | | | | - P. H. Klopfer
- Department of Biology, Duke University, Durham, NC, USA
| | - J. Fietz
- Department of Zoology, University of Hohenheim, Stuttgart, Germany
| | | |
Collapse
|
122
|
Rauch H, Pohlin F, Einwaller J, Habe M, Gasch K, Haw A, Arnold W, Stalder G, Painer J. Effect of season and diet on heart rate and blood pressure in female red deer (Cervus elaphus) anaesthetised with medetomidine-tiletamine-zolazepam. PLoS One 2022; 17:e0268811. [PMID: 35671269 PMCID: PMC9173613 DOI: 10.1371/journal.pone.0268811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 05/09/2022] [Indexed: 11/18/2022] Open
Abstract
Temperate zone ungulates like red deer (Cervus elaphus) show pronounced seasonal acclimatisation. Hypometabolism during winter is associated with cardiovascular changes, including a reduction in heart rate (fH) and temporal peripheral vasoconstriction. How anaesthesia with vasoactive substances such as medetomidine affect the seasonally acclimatised cardiovascular system is not yet known. We anaesthetised eleven healthy female red deer with medetomidine (0.1 mg/kg) and tiletamine/zolazepam (3 mg/kg) twice in winter (ad libitum and restricted feed) and in summer (ad libitum and restricted feed), with a two-week washout-period in-between, to test for the effect of season, food availability and supplementation with omega-3 or omega-6 polyunsaturated fatty acid (PUFA) on fH and arterial blood pressure (ABP) during anaesthesia. Six animals received pellets enriched with omega-6 fatty acids (FA), and five animals with omega-3 FA. Anaesthesia significantly decreased fH in summer but not in winter and ABP was lower in winter (p < 0.05). The combination of omega-6 FA enriched pellets and food restriction resulted in a lower fH and higher ABP during anaesthesia with more pronounced changes in winter (p < 0.001). Our results demonstrate that season, food availability and type of PUFA supplementation in red deer affect the cardiovascular system during anaesthesia.
Collapse
Affiliation(s)
- Hanna Rauch
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Friederike Pohlin
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Joy Einwaller
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Manuela Habe
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Kristina Gasch
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Anna Haw
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Walter Arnold
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Gabrielle Stalder
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
- * E-mail:
| | - Johanna Painer
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| |
Collapse
|
123
|
Alston JM, Dillon ME, Keinath DA, Abernethy IM, Goheen JR. Daily torpor reduces the energetic consequences of microhabitat selection for a widespread bat. Ecology 2022; 103:e3677. [PMID: 35262926 PMCID: PMC9286574 DOI: 10.1002/ecy.3677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 12/16/2021] [Indexed: 11/25/2022]
Abstract
Homeothermy requires increased metabolic rates as temperatures decline below the thermoneutral zone, so homeotherms typically select microhabitats within or near their thermoneutral zones during periods of inactivity. However, many mammals and birds are heterotherms that relax internal controls on body temperature and go into torpor when maintaining a high, stable body temperature, which is energetically costly. Such heterotherms should be less tied to microhabitats near their thermoneutral zones and, because heterotherms spend more time in torpor and expend less energy at colder temperatures, heterotherms may even select microhabitats in which temperatures are well below their thermoneutral zones. We studied how temperature and daily torpor influence the selection of microhabitats (i.e., diurnal roosts) by a heterothermic bat (Myotis thysanodes). We (1) quantified the relationship between ambient temperature and daily duration of torpor, (2) simulated daily energy expenditure over a range of microhabitat temperatures, and (3) quantified the influence of microhabitat temperature on microhabitat selection. In addition, warm microhabitats substantially reduced the energy expenditure of simulated homeothermic bats, and heterothermic bats modulated their use of daily torpor to maintain a constant level of energy expenditure across microhabitats of different temperatures. Daily torpor expanded the range of energetically economical microhabitats, such that microhabitat selection was independent of microhabitat temperature. Our work adds to a growing literature documenting the functions of torpor beyond its historical conceptualization as a last-resort measure to save energy during periods of extended or acute energetic stress.
Collapse
Affiliation(s)
- Jesse M. Alston
- Program in Ecology, Department of Zoology and PhysiologyUniversity of WyomingLaramieWyomingUSA
- Wyoming Natural Diversity DatabaseUniversity of WyomingLaramieWyomingUSA
- Center for Advanced Systems Understanding (CASUS)GörlitzGermany
| | - Michael E. Dillon
- Program in Ecology, Department of Zoology and PhysiologyUniversity of WyomingLaramieWyomingUSA
| | - Douglas A. Keinath
- Wyoming Ecological Services Field OfficeUnited States Fish and Wildlife ServiceCheyenneWyomingUSA
| | - Ian M. Abernethy
- Wyoming Natural Diversity DatabaseUniversity of WyomingLaramieWyomingUSA
| | - Jacob R. Goheen
- Program in Ecology, Department of Zoology and PhysiologyUniversity of WyomingLaramieWyomingUSA
| |
Collapse
|
124
|
Przybylska-Piech AS, Jefimow M. Siberian hamsters nonresponding to short photoperiod use fasting-induced torpor. J Exp Biol 2022; 225:275527. [PMID: 35615921 DOI: 10.1242/jeb.244222] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/17/2022] [Indexed: 11/20/2022]
Abstract
Nonresponding Siberian hamsters Phodopus sungorus do not develop the winter phenotype with white fur, low body mass (mb) and spontaneous torpor use in response to short photoperiod. However, their thermoregulatory response to fasting remains unknown. We measured body temperature and mb of 12 nonresponders acclimated to short photoperiod and then to cold, and fasted four times for 24h. Four individuals used torpor and in total we recorded 19 torpor bouts, which were shallow, short, and occurred at night. Moreover fasting increased the heterothermy index in all hamsters. Low mb was not a prerequisite for torpor use and mb loss correlated with neither heterothermy index nor torpor use. This is the first evidence that individuals which do not develop the winter phenotype, can use torpor or increase body temperature variability to face unpredictable, adverse environmental conditions. Despite the lack of seasonal changes, thermoregulatory adjustments may increase winter survival probability of nonresponders.
Collapse
Affiliation(s)
- Anna S Przybylska-Piech
- Department of Vertebrate Zoology and Ecology; Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
| | - Małgorzata Jefimow
- Department of Animal Physiology and Neurobiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
| |
Collapse
|
125
|
Hypothalamic remodeling of thyroid hormone signaling during hibernation in the arctic ground squirrel. Commun Biol 2022; 5:492. [PMID: 35606540 PMCID: PMC9126913 DOI: 10.1038/s42003-022-03431-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 04/29/2022] [Indexed: 12/16/2022] Open
Abstract
Hibernation involves prolonged intervals of profound metabolic suppression periodically interrupted by brief arousals to euthermy, the function of which is unknown. Annual cycles in mammals are timed by a photoperiodically-regulated thyroid-hormone-dependent mechanism in hypothalamic tanycytes, driven by thyrotropin (TSH) in the pars tuberalis (PT), which regulates local TH-converting deiodinases and triggers remodeling of neuroendocrine pathways. We demonstrate that over the course of hibernation in continuous darkness, arctic ground squirrels (Urocitellus parryii) up-regulate the retrograde TSH/Deiodinase/TH pathway, remodel hypothalamic tanycytes, and activate the reproductive axis. Forcing the premature termination of hibernation by warming animals induced hypothalamic deiodinase expression and the accumulation of secretory granules in PT thyrotrophs and pituitary gonadotrophs, but did not further activate the reproductive axis. We suggest that periodic arousals may allow for the transient activation of hypothalamic thyroid hormone signaling, cellular remodeling, and re-programming of brain circuits in preparation for the short Arctic summer. Arctic ground squirrels hibernating in darkness activate the pars tuberalis - hypothalamus thyroid hormone signaling pathway, remodel hypothalamic tanycytes, and activate the reproductive axis.
Collapse
|
126
|
Petersen PC, Vöröslakos M, Buzsáki G. Brain temperature affects quantitative features of hippocampal sharp wave ripples. J Neurophysiol 2022; 127:1417-1425. [PMID: 35389772 PMCID: PMC9109799 DOI: 10.1152/jn.00047.2022] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/23/2022] [Accepted: 04/04/2022] [Indexed: 11/22/2022] Open
Abstract
Biochemical mechanisms are temperature dependent. Brain temperature shows wide variations across brain states, and such changes may explain quantitative changes in network oscillations. Here, we report on the relationship between various hippocampal sharp wave ripple features to brain temperature. Ripple frequency, occurrence rate, and duration correlated with temperature dynamics. By focal manipulation of the brain temperature in the hippocampal CA1 region, we show that ripple frequency can be increased and decreased by local heating and cooling, respectively. Changes of other parameters, such as the rate of sharp wave-ripple complex (SPW-R) and ripple duration were not consistently affected. Our findings suggest that brain temperature in the CA1 region plays a leading role in affecting ripple frequency, whereas other parameters of SPW-Rs may be determined by mechanisms upstream from the CA1 region. These findings illustrate that physiological variations of brain temperature exert important effects on hippocampal circuit operations.NEW & NOTEWORTHY During physiological conditions, brain temperature fluctuates approximately 3°C between sleep and active waking. Here, we show that features of hippocampal ripples, including the rate of occurrence, peak frequency, and duration are correlated with brain temperature variations. Focal bidirectional manipulation of temperature in the hippocampal CA1 region in awake rodents show that ripple frequency can be altered in the direction expected from the correlational observations, implying that temperature plays a significant role.
Collapse
Affiliation(s)
- Peter C Petersen
- Neuroscience Institute, School of Medicine, New York University, New York City, New York
| | - Mihály Vöröslakos
- Neuroscience Institute, School of Medicine, New York University, New York City, New York
| | - György Buzsáki
- Neuroscience Institute, School of Medicine, New York University, New York City, New York
- Department of Neurology, School of Medicine, New York University, New York City, New York
| |
Collapse
|
127
|
Nespolo RF, Mejias C, Bozinovic F. Why bears hibernate? Redefining the scaling energetics of hibernation. Proc Biol Sci 2022; 289:20220456. [PMID: 35473385 PMCID: PMC9043729 DOI: 10.1098/rspb.2022.0456] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hibernation is a natural state of suspended animation that many mammals experience and has been interpreted as an adaptive strategy for saving energy. However, the actual amount of savings that hibernation represents, and particularly its dependence on body mass (the 'scaling') has not been calculated properly. Here, we estimated the scaling of daily energy expenditure of hibernation (DEEH), covering a range of five orders of magnitude in mass. We found that DEEH scales isometrically with mass, which means that a gram of hibernating bat has a similar metabolism to that of a gram of bear, 20 000 times larger. Given that metabolic rate of active animals scales allometrically, the point where these scaling curves intersect with DEEH represents the mass where energy savings by hibernation are zero. For BMR, these zero savings are attained for a relatively small bear (approx. 75 kg). Calculated on a per cell basis, the cellular metabolic power of hibernation was estimated to be 1.3 × 10-12 ± 2.6 × 10-13 W cell-1, which is lower than the minimum metabolism of isolated mammalian cells. This supports the idea of the existence of a minimum metabolism that permits cells to survive under a combination of cold and hypoxia.
Collapse
Affiliation(s)
- Roberto F Nespolo
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.,Millenium Nucleus of Patagonian Limit of Life (LiLi) and Millennium Institute for Integrative Biology (iBio), Santiago, Chile.,Center for Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Mejias
- Magister en Ecología Aplicada, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.,Millenium Nucleus of Patagonian Limit of Life (LiLi) and Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Francisco Bozinovic
- Center for Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| |
Collapse
|
128
|
HORII Y, OKADERA K, MIYAWAKI S, SHIINA T, SHIMIZU Y. <i>Suncus murinus</i> as a novel model animal that is suitable for elucidating the mechanism of daily torpor. Biomed Res 2022; 43:53-57. [DOI: 10.2220/biomedres.43.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yuuki HORII
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
| | - Kanako OKADERA
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
| | - Shingo MIYAWAKI
- Laboratory of Veterinary Surgery, Faculty of Applied Biological Sciences, Gifu University
| | - Takahiko SHIINA
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
| | - Yasutake SHIMIZU
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
| |
Collapse
|
129
|
Wellbrock AHJ, Eckhardt LRH, Kelsey NA, Heldmaier G, Rozman J, Witte K. Cool birds: first evidence of energy-saving nocturnal torpor in free-living common swifts Apus apus resting in their nests. Biol Lett 2022; 18:20210675. [PMID: 35414223 PMCID: PMC9006018 DOI: 10.1098/rsbl.2021.0675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Daily torpor is a means of saving energy by controlled lowering of the metabolic rate (MR) during resting, usually coupled with a decrease in body temperature. We studied nocturnal daily torpor under natural conditions in free-living common swifts Apus apus resting in their nests as a family using two non-invasive approaches. First, we monitored nest temperature (Tnest) in up to 50 occupied nests per breeding season in 2010-2015. Drops in Tnest were the first indication of torpor. Among 16 673 observations, we detected 423 events of substantial drops in Tnest of on average 8.6°C. Second, we measured MR of the families inside nest-boxes prepared for calorimetric measurements during cold periods in the breeding seasons of 2017 and 2018. We measured oxygen consumption and carbon dioxide production using a mobile indirect respirometer and calculated the percentage reduction in MR. During six torpor events observed, MR was gradually reduced by on average 56% from the reference value followed by a decrease in Tnest of on average 7.6°C. By contrast, MR only decreased by about 33% on nights without torpor. Our field data gave an indication of daily torpor, which is used as a strategy for energy saving in free-living common swifts.
Collapse
Affiliation(s)
- Arndt H J Wellbrock
- Research Group of Ecology and Behavioural Biology, Institute of Biology, University of Siegen, Siegen, Germany.,Institute of Avian Research 'Vogelwarte Helgoland', Wilhelmshaven, Germany
| | - Luca R H Eckhardt
- Research Group of Ecology and Behavioural Biology, Institute of Biology, University of Siegen, Siegen, Germany
| | - Natalie A Kelsey
- Research Group of Ecology and Behavioural Biology, Institute of Biology, University of Siegen, Siegen, Germany.,Institute of Avian Research 'Vogelwarte Helgoland', Wilhelmshaven, Germany
| | - Gerhard Heldmaier
- Animal Physiology, Faculty of Biology, Marburg University, Marburg, Germany
| | - Jan Rozman
- Research Group of Ecology and Behavioural Biology, Institute of Biology, University of Siegen, Siegen, Germany.,Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Klaudia Witte
- Research Group of Ecology and Behavioural Biology, Institute of Biology, University of Siegen, Siegen, Germany
| |
Collapse
|
130
|
Ambler M, Hitrec T, Pickering A. Turn it off and on again: characteristics and control of torpor. Wellcome Open Res 2022; 6:313. [PMID: 35087956 PMCID: PMC8764563 DOI: 10.12688/wellcomeopenres.17379.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2022] [Indexed: 11/20/2022] Open
Abstract
Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to review the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.
Collapse
Affiliation(s)
- Michael Ambler
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Timna Hitrec
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Anthony Pickering
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| |
Collapse
|
131
|
Fjelldal MA, Sørås R, Stawski C. Universality of torpor expression in bats. Physiol Biochem Zool 2022; 95:326-339. [DOI: 10.1086/720273] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
132
|
Grigg G, Nowack J, Bicudo JEPW, Bal NC, Woodward HN, Seymour RS. Whole-body endothermy: ancient, homologous and widespread among the ancestors of mammals, birds and crocodylians. Biol Rev Camb Philos Soc 2022; 97:766-801. [PMID: 34894040 PMCID: PMC9300183 DOI: 10.1111/brv.12822] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 12/31/2022]
Abstract
The whole-body (tachymetabolic) endothermy seen in modern birds and mammals is long held to have evolved independently in each group, a reasonable assumption when it was believed that its earliest appearances in birds and mammals arose many millions of years apart. That assumption is consistent with current acceptance that the non-shivering thermogenesis (NST) component of regulatory body heat originates differently in each group: from skeletal muscle in birds and from brown adipose tissue (BAT) in mammals. However, BAT is absent in monotremes, marsupials, and many eutherians, all whole-body endotherms. Indeed, recent research implies that BAT-driven NST originated more recently and that the biochemical processes driving muscle NST in birds, many modern mammals and the ancestors of both may be similar, deriving from controlled 'slippage' of Ca2+ from the sarcoplasmic reticulum Ca2+ -ATPase (SERCA) in skeletal muscle, similar to a process seen in some fishes. This similarity prompted our realisation that the capacity for whole-body endothermy could even have pre-dated the divergence of Amniota into Synapsida and Sauropsida, leading us to hypothesise the homology of whole-body endothermy in birds and mammals, in contrast to the current assumption of their independent (convergent) evolution. To explore the extent of similarity between muscle NST in mammals and birds we undertook a detailed review of these processes and their control in each group. We found considerable but not complete similarity between them: in extant mammals the 'slippage' is controlled by the protein sarcolipin (SLN), in birds the SLN is slightly different structurally and its role in NST is not yet proved. However, considering the multi-millions of years since the separation of synapsids and diapsids, we consider that the similarity between NST production in birds and mammals is consistent with their whole-body endothermy being homologous. If so, we should expect to find evidence for it much earlier and more widespread among extinct amniotes than is currently recognised. Accordingly, we conducted an extensive survey of the palaeontological literature using established proxies. Fossil bone histology reveals evidence of sustained rapid growth rates indicating tachymetabolism. Large body size and erect stature indicate high systemic arterial blood pressures and four-chambered hearts, characteristic of tachymetabolism. Large nutrient foramina in long bones are indicative of high bone perfusion for rapid somatic growth and for repair of microfractures caused by intense locomotion. Obligate bipedality appeared early and only in whole-body endotherms. Isotopic profiles of fossil material indicate endothermic levels of body temperature. These proxies led us to compelling evidence for the widespread occurrence of whole-body endothermy among numerous extinct synapsids and sauropsids, and very early in each clade's family tree. These results are consistent with and support our hypothesis that tachymetabolic endothermy is plesiomorphic in Amniota. A hypothetical structure for the heart of the earliest endothermic amniotes is proposed. We conclude that there is strong evidence for whole-body endothermy being ancient and widespread among amniotes and that the similarity of biochemical processes driving muscle NST in extant birds and mammals strengthens the case for its plesiomorphy.
Collapse
Affiliation(s)
- Gordon Grigg
- School of Biological SciencesUniversity of QueenslandBrisbaneQLD4072Australia
| | - Julia Nowack
- School of Biological and Environmental SciencesLiverpool John Moores UniversityJames Parsons Building, Byrom StreetLiverpoolL3 3AFU.K.
| | | | | | - Holly N. Woodward
- Oklahoma State University Center for Health SciencesTulsaOK74107U.S.A.
| | - Roger S. Seymour
- School of Biological SciencesUniversity of AdelaideAdelaideSA5005Australia
| |
Collapse
|
133
|
Green SR, Al-Attar R, McKechnie AE, Naidoo S, Storey KB. Phosphorylation status of pyruvate dehydrogenase in the mousebird Colius striatus undergoing torpor. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:337-345. [PMID: 34951526 DOI: 10.1002/jez.2570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 12/07/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
Torpor is a heterothermic response that occurs in some animals to reduce metabolic expenditure. The speckled mousebird (Colius striatus) belongs to one of the few avian taxa possessing the capacity for pronounced torpor, entering a hypometabolic state with concomitant decreases in body temperature in response to reduced food access or elevated thermoregulatory energy requirements. The pyruvate dehydrogenase complex (PDC) is a crucial site regulating metabolism by bridging glycolysis and the Krebs cycle. Three highly conserved phosphorylation sites are found within the E1 enzyme of the complex that inhibit PDC activity and reduce the flow of carbohydrate substrates into the mitochondria. The current study demonstrates a marked increase in S232 phosphorylation during torpor in liver, heart, and skeletal muscle of C. striatus. The increase in S232 phosphorylation during torpor was particularly notable in skeletal muscle where levels were ~49-fold higher in torpid birds compared to controls. This was in contrast to the other two phosphorylation sites (S293 and S300) which remained consistently phosphorylated regardless of tissue. The relevant PDH kinase (PDHK1) known to phosphorylate S232 was found to be substantially upregulated (~5-fold change) in the muscle during torpor as well as increasing moderately in the liver (~2.2-fold increase). Additionally, in the heart, a slight (~23%) decrease in total PDH levels was noted. Taken together the phosphorylation changes in PDH suggest that inhibition of the complex is a common feature across several tissues in the mousebird during torpor and that this regulation is mediated at a specific residue.
Collapse
Affiliation(s)
- Stuart R Green
- Department of Biology, Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Rasha Al-Attar
- Department of Biology, Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
- McEwen Stem Cell Institute, University Health Network, Toronto, Ontario, Canada
| | - Andrew E McKechnie
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria, South Africa
- Department of Zoology and Entomology, DSI-NRF Centre of Excellence at the FitzPatrick Institute, University of Pretoria, Hatfield, South Africa
| | - Samantha Naidoo
- Department of Zoology and Entomology, DSI-NRF Centre of Excellence at the FitzPatrick Institute, University of Pretoria, Hatfield, South Africa
| | - Kenneth B Storey
- Department of Biology, Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| |
Collapse
|
134
|
Mejías C, Navedo J, Sabat P, Franco LM, Bozinovic F, Nespolo RF. Body Composition and Energy Savings by Hibernation: Lessons from the South American Marsupial Dromiciops gliroides. Physiol Biochem Zool 2022; 95:239-250. [DOI: 10.1086/719932] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
135
|
Collier K, Parsons S, Czenze ZJ. Thermal energetics of male courtship song in a lek-breeding bat. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03141-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
136
|
Klüg-Baerwald BJ, Lausen CL, Wissel B, Brigham RM. Meet You at the Local Watering Hole? No Use of an Artificial Water Resource, and Evidence of Dehydration in Hibernating Bats in the Prairies. ACTA CHIROPTEROLOGICA 2022. [DOI: 10.3161/15081109acc2021.23.2.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Cori L. Lausen
- Wildlife Conservation Society of Canada, PO Box 606, Kaslo, BC V0G 1M0 Canada
| | - Bjoern Wissel
- Department of Biology, University of Regina, Regina, SK S4S 0A2 Canada
| | - R. Mark Brigham
- Department of Biology, University of Regina, Regina, SK S4S 0A2 Canada
| |
Collapse
|
137
|
Komar E, Fasel NJ, Szafrańska PA, Dechmann DKN, Zegarek M, Ruczyński I. Energy allocation shifts from sperm production to self-maintenance at low temperatures in male bats. Sci Rep 2022; 12:2138. [PMID: 35136106 PMCID: PMC8826387 DOI: 10.1038/s41598-022-05896-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/21/2021] [Indexed: 11/17/2022] Open
Abstract
The ability of animals to produce endogenous heat provides a buffer against environmental changes but also incurs high energetic costs. Especially small endothermic mammals have high energy demands. Some temperate-zone species (heterotherms) regularly use torpor, which slows down their entire metabolism but also potentially delays reproduction, to compensate for this. We used a unique experimental approach to test the consequences of extended low and high ambient temperatures on the trade-off in energy allocation to body mass maintenance, thermoregulation effort and seasonal sexual maturation in temperate zone male bats. We showed that long exposure to low ambient temperature shifts energy allocation away from sexual maturation to self-maintenance and results in a delay of sperm maturation by as much as an entire month. This effect was partially buffered by higher body mass. Heavier bats were able to afford more intensive thermoregulation and consequently speed up maturation. Interestingly, bats at constant high temperatures avoided deep torpor and matured faster than those at low temperatures, but sperm production was also slower than under natural conditions. Our results show that not only low, but also constant high ambient temperatures are detrimental during seasonal sexual maturation and the trade-off between investing into self-maintenance and fitness is a finely tuned compromise.
Collapse
Affiliation(s)
- Ewa Komar
- Mammal Research Institute, Polish Academy of Sciences, Stoczek 1, Białowieża, Poland. .,Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warszawa, Poland.
| | - Nicolas J Fasel
- Department of Ecology and Evolution, University of Lausanne, 1015, Biophore, Switzerland
| | - Paulina A Szafrańska
- Mammal Research Institute, Polish Academy of Sciences, Stoczek 1, Białowieża, Poland
| | - D K N Dechmann
- Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315, Radolfzell, Germany.,Department of Biology, University of Konstanz, Universitätsstraße 10, 78457, Konstanz, Germany
| | - Marcin Zegarek
- Mammal Research Institute, Polish Academy of Sciences, Stoczek 1, Białowieża, Poland
| | - Ireneusz Ruczyński
- Mammal Research Institute, Polish Academy of Sciences, Stoczek 1, Białowieża, Poland
| |
Collapse
|
138
|
Schmaljohann H, Eikenaar C, Sapir N. Understanding the ecological and evolutionary function of stopover in migrating birds. Biol Rev Camb Philos Soc 2022; 97:1231-1252. [PMID: 35137518 DOI: 10.1111/brv.12839] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 12/14/2022]
Abstract
Global movement patterns of migratory birds illustrate their fascinating physical and physiological abilities to cross continents and oceans. During their voyages, most birds land multiple times to make so-called 'stopovers'. Our current knowledge on the functions of stopover is mainly based on the proximate study of departure decisions. However, such studies are insufficient to gauge fully the ecological and evolutionary functions of stopover. If we study how a focal trait, e.g. changes in energy stores, affects the decision to depart from a stopover without considering the trait(s) that actually caused the bird to land, e.g. unfavourable environmental conditions for flight, we misinterpret the function of the stopover. It is thus important to realise and acknowledge that stopovers have many different functions, and that not every migrant has the same (set of) reasons to stop-over. Additionally, we may obtain contradictory results because the significance of different traits to a migrant is context dependent. For instance, late spring migrants may be more prone to risk-taking and depart from a stopover with lower energy stores than early spring migrants. Thus, we neglect that departure decisions are subject to selection to minimise immediate (mortality risk) and/or delayed (low future reproductive output) fitness costs. To alleviate these issues, we first define stopover as an interruption of migratory endurance flight to minimise immediate and/or delayed fitness costs. Second, we review all probable functions of stopover, which include accumulating energy, various forms of physiological recovery and avoiding adverse environmental conditions for flight, and list potential other functions that are less well studied, such as minimising predation, recovery from physical exhaustion and spatiotemporal adjustments to migration. Third, derived from these aspects, we argue for a paradigm shift in stopover ecology research. This includes focusing on why an individual interrupts its migratory flight, which is more likely to identify the individual-specific function(s) of the stopover correctly than departure-decision studies. Moreover, we highlight that the selective forces acting on stopover decisions are context dependent and are expected to differ between, e.g. K-/r-selected species, the sexes and migration strategies. For example, all else being equal, r-selected species (low survival rate, high reproductive rate) should have a stronger urge to continue the migratory endurance flight or resume migration from a stopover because the potential increase in immediate fitness costs suffered from a flight is offset by the expected higher reproductive success in the subsequent breeding season. Finally, we propose to focus less on proximate mechanisms controlling landing and departure decisions, and more on ultimate mechanisms to identify the selective forces shaping stopover decisions. Our ideas are not limited to birds but can be applied to any migratory species. Our revised definition of stopover and the proposed paradigm shift has the potential to stimulate a fruitful discussion towards a better evolutionary ecological understanding of the functions of stopover. Furthermore, identifying the functions of stopover will support targeted measures to conserve and restore the functionality of stopover sites threatened by anthropogenic environmental changes. This is especially important for long-distance migrants, which currently are in alarming decline.
Collapse
Affiliation(s)
- Heiko Schmaljohann
- Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, Oldenburg, 26129, Germany.,Institute of Avian Research, An der Vogelwarte 21, Wilhelmshaven, 26386, Germany
| | - Cas Eikenaar
- Institute of Avian Research, An der Vogelwarte 21, Wilhelmshaven, 26386, Germany
| | - Nir Sapir
- Department of Evolutionary and Environmental Biology and the Institute of Evolution, University of Haifa, 199 Aba Khoushy Ave, Haifa, 3498838, Israel
| |
Collapse
|
139
|
Fasel NJ, Vullioud C, Genoud M. Assigning metabolic rate measurements to torpor and euthermy in heterothermic endotherms: "torpor", a new package for R. Biol Open 2022; 11:274272. [PMID: 35128558 PMCID: PMC9002798 DOI: 10.1242/bio.059064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 01/27/2022] [Indexed: 11/21/2022] Open
Abstract
Torpor is a state of controlled reduction of metabolic rate (M) in endotherms. Assigning measurements of M to torpor or euthermy can be challenging, especially when the difference between euthermic M and torpid M is small, in species defending a high minimal body temperature in torpor, in thermolabile species, and slightly below the thermoneutral zone (TNZ). Here, we propose a novel method for distinguishing torpor from euthermy. We use the variation in M measured during euthermic rest and torpor at varying ambient temperatures (Ta) to objectively estimate the lower critical temperature (Tlc) of the TNZ and to assign measurements to torpor, euthermic rest or rest within TNZ. In addition, this method allows the prediction of M during euthermic rest and torpor at varying Ta, including resting M within the TNZ. The present method has shown highly satisfactory results using 28 published sets of metabolic data obtained by respirometry on 26 species of mammals. Ultimately, this novel method aims to facilitate analysis of respirometry data in heterothermic endotherms. Finally, the development of the associated R-package (torpor) will enable widespread use of the method amongst biologists. Summary: The presented method and its associated R-package (torpor) enable the assignment of metabolic rate measurements to torpor or euthermy, ultimately improving the standardization of respirometry analyses in heterotherms.
Collapse
Affiliation(s)
- Nicolas J Fasel
- Department of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Colin Vullioud
- Department Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, D-10315 Berlin, Germany
| | - Michel Genoud
- Department of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland
| |
Collapse
|
140
|
Fontúrbel FE, Franco LM, Bozinovic F, Quintero‐Galvis JF, Mejías C, Amico GC, Vazquez MS, Sabat P, Sánchez‐Hernández JC, Watson DM, Saenz‐Agudelo P, Nespolo RF. The ecology and evolution of the monito del monte, a relict species from the southern South America temperate forests. Ecol Evol 2022; 12:e8645. [PMID: 35261741 PMCID: PMC8888251 DOI: 10.1002/ece3.8645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 12/23/2022] Open
Abstract
The arboreal marsupial monito del monte (genus Dromiciops, with two recognized species) is a paradigmatic mammal. It is the sole living representative of the order Microbiotheria, the ancestor lineage of Australian marsupials. Also, this marsupial is the unique frugivorous mammal in the temperate rainforest, being the main seed disperser of several endemic plants of this ecosystem, thus acting as keystone species. Dromiciops is also one of the few hibernating mammals in South America, spending half of the year in a physiological dormancy where metabolism is reduced to 10% of normal levels. This capacity to reduce energy expenditure in winter contrasts with the enormous energy turnover rate they experience in spring and summer. The unique life history strategies of this living Microbiotheria, characterized by an alternation of life in the slow and fast lanes, putatively represent ancestral traits that permitted these cold-adapted mammals to survive in this environment. Here, we describe the ecological role of this emblematic marsupial, summarizing the ecophysiology of hibernation and sociality, updated phylogeographic relationships, reproductive cycle, trophic relationships, mutualisms, conservation, and threats. This marsupial shows high densities, despite presenting slow reproductive rates, a paradox explained by the unique characteristics of its three-dimensional habitat. We finally suggest immediate actions to protect these species that may be threatened in the near future due to habitat destruction and climate change.
Collapse
Affiliation(s)
- Francisco E. Fontúrbel
- Instituto de BiologíaPontificia Universidad Católica de ValparaísoValparaísoChile
- Millennium Nucleus of Patagonian Limit of Life (LiLi)SantiagoChile
| | - Lida M. Franco
- Facultad de Ciencias Naturales y MatemáticasUniversidad de IbaguéIbaguéColombia
| | - Francisco Bozinovic
- Departamento de EcologíaFacultad de Ciencias BiológicasCenter of Applied Ecology and Sustainability (CAPES)Pontificia Universidad Católica de ChileSantiagoChile
| | | | - Carlos Mejías
- Instituto de Ciencias Ambientales y EvolutivasUniversidad Austral de ChileValdiviaChile
| | | | | | - Pablo Sabat
- Departamento de Ciencias EcológicasFacultad de CienciasUniversidad de ChileSantiagoChile
| | | | - David M. Watson
- School of Agricultural, Environmental and Veterinary SciencesCharles Sturt UniversityAlburyNSWAustralia
| | - Pablo Saenz‐Agudelo
- Instituto de Ciencias Ambientales y EvolutivasUniversidad Austral de ChileValdiviaChile
| | - Roberto F. Nespolo
- Millennium Nucleus of Patagonian Limit of Life (LiLi)SantiagoChile
- Departamento de EcologíaFacultad de Ciencias BiológicasCenter of Applied Ecology and Sustainability (CAPES)Pontificia Universidad Católica de ChileSantiagoChile
- Instituto de Ciencias Ambientales y EvolutivasUniversidad Austral de ChileValdiviaChile
- Millennium Institute for Integrative Biology (iBio)SantiagoChile
| |
Collapse
|
141
|
do Amaral-Silva L, da Silva WC, Gargaglioni LH, Bícego KC. Metabolic trade-offs favor regulated hypothermia and inhibit fever in immune-challenged chicks. J Exp Biol 2022; 225:274497. [DOI: 10.1242/jeb.243115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 01/24/2022] [Indexed: 11/20/2022]
Abstract
The febrile response to resist a pathogen is energetically expensive while regulated hypothermia seems to preserve energy for vital functions. We hypothesized here that immune challenged birds under metabolic trade-offs (reduced energy supply / increased energy demand) favor a regulated hypothermic response at the expense of fever. To test this hypothesis, we compared 5-days old broiler chicks exposed to fasting, cold (25oC), and fasting combined with cold to a control group fed at thermoneutral condition (30oC). The chicks were injected with saline or with a high dose of endotoxin known to induce a biphasic thermal response composed of body temperature (Tb) drop followed by fever. Then Tb, oxygen consumption (metabolic rate), peripheral vasomotion (cutaneous heat exchange), breathing frequency (respiratory heat exchange), and huddling behavior (heat conservation indicator) were analyzed. Irrespective of metabolic trade-offs, chicks presented a transient regulated hypothermia in the first hour, which relied on a suppressed metabolic rate for all groups, increased breathing frequency for chicks fed/fasted at 30oC, and peripheral vasodilation in fed/fasted chicks at 25oC. Fever was observed only in chicks kept at thermoneutrality and was supported by peripheral vasoconstriction and huddling behavior. Fed and fasted chicks at 25oC completely eliminated fever despite the ability to increase metabolic rate for thermogenesis in the phase correspondent to fever when it was pharmacologically induced by 2.4-Dinitrophenol. Our data suggest that increased competing demands affect chicks’ response to an immune challenge favoring regulated hypothermia to preserve energy while the high costs of fever to resist a pathogen are avoided.
Collapse
Affiliation(s)
- Lara do Amaral-Silva
- Department of Animal Morphology and Physiology, São Paulo State University (FCAV-UNESP), Jaboticabal, SP, Brazil
- Department of Biology, University of North Carolina at Greensboro (UNCG), Greensboro, NC, USA
| | - Welex Cândido da Silva
- Department of Animal Morphology and Physiology, São Paulo State University (FCAV-UNESP), Jaboticabal, SP, Brazil
| | - Luciane Helena Gargaglioni
- Department of Animal Morphology and Physiology, São Paulo State University (FCAV-UNESP), Jaboticabal, SP, Brazil
| | - Kênia Cardoso Bícego
- Department of Animal Morphology and Physiology, São Paulo State University (FCAV-UNESP), Jaboticabal, SP, Brazil
| |
Collapse
|
142
|
Meier F, Grosche L, Reusch C, Runkel V, van Schaik J, Kerth G. Long-term individualized monitoring of sympatric bat species reveals distinct species- and demographic differences in hibernation phenology. BMC Ecol Evol 2022; 22:7. [PMID: 35090401 PMCID: PMC8796590 DOI: 10.1186/s12862-022-01962-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/13/2022] [Indexed: 11/21/2022] Open
Abstract
Background Hibernation allows species to conserve energy and thereby bridge unfavorable environmental conditions. At the same time, hibernation imposes substantial ecological and physiological costs. Understanding how hibernation timing differs within and between species can provide insights into the underlying drivers of this trade-off. However, this requires individualized long-term data that are often unavailable. Here, we used automatic monitoring techniques and a reproducible analysis pipeline to assess the individualized hibernation phenology of two sympatric bat species. Our study is based on data of more than 1100 RFID-tagged Daubenton’s bats (Myotis daubentonii) and Natterer’s bats (Myotis nattereri) collected over seven years at a hibernaculum in Germany. We used linear mixed models to analyze species-, sex- and age-specific differences in entrance, emergence and duration of the longest continuous period spent in the hibernaculum. Results Overall, Daubenton’s bats entered the hibernaculum earlier and emerged later than Natterer’s bats, resulting in a nearly twice as long hibernation duration. In both species, adult females entered earlier and emerged from hibernation later than adult males. Hibernation duration was shorter for juveniles than adults with the exception of adult male Natterer’s bats whose hibernation duration was shortest of all classes. Finally, hibernation timing differed among years, but yearly variations in entrance and emergence timing were not equally shifted in both species. Conclusions Our results suggest that even in sympatric species, and across sex and age classes, hibernation timing may be differentially affected by environmental conditions. This highlights the necessity of using individualized information when studying the impact of changing environments on hibernation phenology. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-01962-6.
Collapse
Affiliation(s)
- Frauke Meier
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany.
| | - Leo Grosche
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
| | - Christine Reusch
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany.,Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Volker Runkel
- BVF Bundesverband für Fledermauskunde Deutschland e.V., Erfurt, Germany
| | - Jaap van Schaik
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
| | - Gerald Kerth
- Zoological Institute and Museum, Applied Zoology and Nature Conservation, Greifswald University, Greifswald, Germany
| |
Collapse
|
143
|
Muñoz-Garcia A, Ben-Hamo M, Pilosof S, Williams JB, Korine C. Habitat aridity as a determinant of the trade-off between water conservation and evaporative heat loss in bats. J Comp Physiol B 2022; 192:325-333. [PMID: 35037994 DOI: 10.1007/s00360-021-01425-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 11/29/2021] [Accepted: 12/20/2021] [Indexed: 11/26/2022]
Abstract
The maintenance of water balance in arid environments might represent a formidable challenge for Chiroptera, since they have high surface-to-volume ratios. In deserts, bats conserve water, for example, using daily torpor, but they also might experience episodic heat bouts, when they may need to increase total evaporative water loss (TEWL) to thermoregulate. We hypothesized that in bats, habitat aridity and its variability determine a trade-off between water conservation and thermoregulation via evaporative means. To test this hypothesis, we collated data from the literature of 22 species of bats on TEWL, body temperature and resting metabolic rate, in torpor and euthermy. We also collected data on ambient temperature (Ta) and precipitation of the locations where bats were captured, calculated an aridity index, and built an index of variability of the environment. After correcting for phylogeny, we found that, as aridity and variability of the environment increased, bats had lower values of TEWL, but the rate at which TEWL increases with Ta was higher, supporting our hypothesis. These results suggest that at high Ta there is a trade-off between water conservation and evaporative heat loss in bats. The evolution of physiological mechanisms that allow water conservation and tolerance to conditions of high Ta without access to free water might thus be crucial to explain the distribution of desert bats.
Collapse
Affiliation(s)
- Agustí Muñoz-Garcia
- Department of Evolution, Ecology and Organismal Biology, Ohio State University at Mansfield, 1730 University Dr., Mansfield, OH, 44906, USA.
| | - Miriam Ben-Hamo
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben-Gurion, Israel
| | - Shai Pilosof
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben-Gurion, Israel
| | - Joseph B Williams
- Aronoff Laboratory, Department of Evolution, Ecology and Organismal Biology, Ohio State University, 318 W 12th Ave., Columbus, OH, 43210, USA
| | - Carmi Korine
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben-Gurion, Israel
| |
Collapse
|
144
|
Jenni-Eiermann S, Olano Marin J, Bize P. Variation in feather corticosterone levels in Alpine swift nestlings provides support for the hypo-responsive hypothesis. Gen Comp Endocrinol 2022; 316:113946. [PMID: 34822843 DOI: 10.1016/j.ygcen.2021.113946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 10/27/2021] [Accepted: 11/18/2021] [Indexed: 01/01/2023]
Abstract
In birds, feather corticosterone values (CORTf) are increasingly used as a retrospective and integrative proxy of an individual's physiological state during the period of feather growth. Relatively high CORTf values are usually interpreted as an indicator of exposure to energy-demanding or stressful conditions during feather growth. However, in nestlings this interpretation might not always hold true. The reasons are that, firstly nestlings (especially altricial ones) still develop their hypothalamo-pituitary-adrenal (HPA) reactivity during the growth of their feathers. Hence, at a young age, nestlings might be unable to mount a substantial adrenocortical stress response. Secondly, some species are able to down-regulate their metabolism during food scarcity and therewith probably also their CORT release. Consequently, CORTf values may not unambiguously reflect whether nestlings have suffered from energy-demanding or stress situations. Relatively high CORTf values might indicate either energy-demanding or stressful conditions ('stress responsive hypothesis'), or - conversely - favourable conditions during the period of feather growth ('hypo-responsive hypothesis'). In the altricial Alpine swift (Tachymarptis melba), we tested which factors help to distinguish between the two hypotheses by considering factors which affect CORT release (brood size, weather) and factors which are affected by high CORT levels (nestling size and condition). We measured CORTf in 205 nestlings over 7 years and collected data on brood size, body size, body condition and prevailing weather. Nestling CORTf values were positively correlated with body condition and negatively with adverse weather, supporting the hypo-responsive hypothesis. Results from the Alpine swift study, supplemented with a survey of the literature, show that relatively easily collected parameters on brood size, nestling size and condition, and environmental factors can help to distinguish between the two hypotheses. A meaningful interpretation of nestling CORTf should only be made in the context of species-specific traits.
Collapse
Affiliation(s)
| | | | - Pierre Bize
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, AB24 2TZ, UK
| |
Collapse
|
145
|
Shankar A, Cisneros INH, Thompson S, Graham CH, Powers DR. A heterothermic spectrum in hummingbirds. J Exp Biol 2022; 225:273909. [PMID: 34989393 DOI: 10.1242/jeb.243208] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/29/2021] [Indexed: 11/20/2022]
Abstract
Many endotherms use torpor, saving energy by a controlled reduction of their body temperature and metabolic rate. Some species (e.g., arctic ground squirrels, hummingbirds) enter deep torpor, dropping their body temperatures by 23-37°C, while others can only enter shallow torpor (e.g., pigeons, 3-10°C reductions). However, deep torpor in mammals can increase predation risk (unless animals are in burrows or caves), inhibit immune function, and result in sleep deprivation, so even for species that can enter deep torpor, facultative shallow torpor might help balance energy savings with these potential costs. Deep torpor occurs in three avian orders, but the trade-offs of deep torpor in birds are unknown. Although the literature hints that some bird species (mousebirds and perhaps hummingbirds) can use both shallow and deep torpor, little empirical evidence of such an avian heterothermy spectrum within species exists. We infrared imaged three hummingbird species that are known to use deep torpor, under natural temperature and light cycles, to test if they were also capable of shallow torpor. All three species used both deep and shallow torpor, often on the same night. Depending on the species, they used shallow torpor for 5-35% of the night. The presence of a heterothermic spectrum in these bird species indicates a capacity for fine-scale physiological and genetic regulation of avian torpid metabolism.
Collapse
Affiliation(s)
- Anusha Shankar
- Stony Brook University, Stony Brook, NY 11794, USA.,Swiss Federal Research Institute (WSL), Birmensdorf, CH-8903, Switzerland
| | | | | | - Catherine H Graham
- Stony Brook University, Stony Brook, NY 11794, USA.,Swiss Federal Research Institute (WSL), Birmensdorf, CH-8903, Switzerland
| | | |
Collapse
|
146
|
Blanco MB, Greene LK, Klopfer PH, Lynch D, Browning J, Ehmke EE, Yoder AD. Body Mass and Tail Girth Predict Hibernation Expression in Captive Dwarf Lemurs. Physiol Biochem Zool 2022; 95:122-129. [PMID: 34986077 DOI: 10.1086/718222] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractHibernation, a metabolic strategy, allows individuals to reduce energetic demands in times of energetic deficits. Hibernation is pervasive in nature, occurring in all major mammalian lineages and geographical regions; however, its expression is variable across species, populations, and individuals, suggesting that trade-offs are at play. Whereas hibernation reduces energy expenditure, energetically expensive arousals may impose physiological burdens. The torpor optimization hypothesis posits that hibernation should be expressed according to energy availability. The greater the energy surplus, the lower the hibernation output. The thrifty female hypothesis, a variation of the torpor optimization hypothesis, states that females should conserve more energy because of their more substantial reproductive costs. Contrarily, if hibernation's benefits offset its costs, hibernation may be maximized rather than optimized (e.g., hibernators with greater fat reserves could afford to hibernate longer). We assessed torpor expression in captive dwarf lemurs, primates that are obligate, seasonal, and tropical hibernators. Across 4.5 mo in winter, we subjected eight individuals at the Duke Lemur Center to conditions conducive to hibernation, recorded estimates of skin temperature hourly (a proxy for torpor), and determined body mass and tail fat reserves bimonthly. Across and between consecutive weigh-ins, heavier dwarf lemurs spent less time in torpor and lost more body mass. At equivalent body mass, females spent more time torpid and better conserved energy than did males. Although preliminary, our results support the torpor optimization and thrifty female hypotheses, suggesting that individuals optimize rather than maximize torpor according to body mass. These patterns are consistent with hibernation phenology in Madagascar, where dwarf lemurs hibernate longer in more seasonal habitats.
Collapse
|
147
|
A critique on the theory of homeostasis. Physiol Behav 2022; 247:113712. [DOI: 10.1016/j.physbeh.2022.113712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 01/27/2023]
|
148
|
Geyer B, Erickson NA, Müller K, Grübel S, Hueber B, Hetz SK, Brecht M. Establishing and Maintaining an Etruscan Shrew Colony. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2022; 61:52-60. [PMID: 34772472 PMCID: PMC8786385 DOI: 10.30802/aalas-jaalas-21-000068] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/28/2021] [Accepted: 07/14/2021] [Indexed: 11/05/2022]
Abstract
The Etruscan shrew (Suncus etruscus) is one of the smallest mammals on earth and is used in many fields of research, including physiology, behavioral science and neuroscience. However, establishing and maintaining a breeding colony of this species in the laboratory can be challenging, as it requires specific husbandry conditions that greatly differ from those of more common laboratory species such as mice or rats. Over the past 15 y, we have successfully established a long-term thriving colony of 150 to 200 animals originating from 36 founders. The colony shows longer life expectancy and larger litter sizes than wild conspecifics. Breeding occurs year-round, independent of seasons, and a breeding pair can regularly produce 2 to 6 offspring with an average life expectancy of more than 3 y. The shrews are housed in glass or plastic enclosures on a specific soil-sand-mixture bedding and are provided with hideouts and nesting material consisting of moss, wood, or bark. Due to their high basal metabolic rate, the shrews require food intake greater than their body weight per day, can hunt arthropods as large as themselves, and cannot survive more than a few hours without food. Live feed such as crickets or mealworms is crucial and must be provided daily or, at the very least, every 2 d. Although our husbandry practices have constantly been adapted and refined, shrew husbandry remains challenging, and great care is necessary to meet the specific needs of this species. Here, we describe the establishment of a long-term stable colony of Etruscan shrews in a research animal facility and the specific husbandry requirements for animal wellbeing.
Collapse
Affiliation(s)
- Beatrice Geyer
- Humboldt-University zu Berlin, Technical Division, Animal Welfare, Berlin, Germany
| | - Nancy A Erickson
- MF 3, Animal Facility, Method Development and Research Infrastructure, Robert Koch-Institute, Berlin, Germany
- Institute of Animal Welfare, Animal Behavior, and Laboratory Animal Science, Freie Universität Berlin, German
| | - Katja Müller
- Humboldt- University zu Berlin, Institute of Biology, Molecular Parasitology, Berlin, German
| | - Susanne Grübel
- Bernstein Center for Computational Neuroscience, Humboldt-University zu Berlin, Berlin, Germany
| | - Barbara Hueber
- GIM Gesellschaft fuer innovative Mikrooekologie mbH, Michendorf, Brandenburg, Germany
| | - Stefan K Hetz
- Bernstein Center for Computational Neuroscience, Humboldt-University zu Berlin, Berlin, Germany
- Zentralverband Zoologischer Fachbetriebe e.V, Wiesbaden, Germany
| | - Michael Brecht
- Bernstein Center for Computational Neuroscience, Humboldt-University zu Berlin, Berlin, Germany
| |
Collapse
|
149
|
Hadj-Moussa H, Hawkins LJ, Storey KB. Role of MicroRNAs in Extreme Animal Survival Strategies. Methods Mol Biol 2022; 2257:311-347. [PMID: 34432286 DOI: 10.1007/978-1-0716-1170-8_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The critical role microRNAs play in modulating global functions is emerging, both in the maintenance of homeostatic mechanisms and in the adaptation to diverse environmental stresses. When stressed, cells must divert metabolic requirements toward immediate survival and eventual recovery and the unique features of miRNAs, such as their relatively ATP-inexpensive biogenesis costs, and the quick and reversible nature of their action, renders them excellent "master controllers" for rapid responses. Many animal survival strategies for dealing with extreme environmental pressures involve prolonged retreats into states of suspended animation to extend the time that they can survive on their limited internal fuel reserves until conditions improve. The ability to retreat into such hypometabolic states is only possible by coupling the global suppression of nonessential energy-expensive functions with an activation of prosurvival networks, a process in which miRNAs are now known to play a major role. In this chapter, we discuss the activation, expression, biogenesis, and unique attributes of miRNA regulation required to facilitate profound metabolic rate depression and implement stress-specific metabolic adaptations. We examine the role of miRNA in strategies of biochemical adaptation including mammalian hibernation, freeze tolerance, freeze avoidance, anoxia and hypoxia survival, estivation, and dehydration tolerance. By comparing these seemingly different adaptive programs in traditional and exotic animal models, we highlight both unique and conserved miRNA-meditated mechanisms for survival. Additional topics discussed include transcription factor networks, temperature dependent miRNA-targeting, and novel species-specific and stress-specific miRNAs.
Collapse
Affiliation(s)
| | - Liam J Hawkins
- Department of Biology, Carleton University, Ottawa, ON, Canada
| | | |
Collapse
|
150
|
Dissimilar use of an external heat source for thermoregulation by shrews from different geographic regions. J Therm Biol 2022; 104:103193. [DOI: 10.1016/j.jtherbio.2022.103193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 11/18/2022]
|