1
|
Iwińska K, Wirowska M, Borowski Z, Boratyński Z, Solecki P, Ciesielski M, Boratyński JS. Energy allocation is revealed while behavioural performance persists after fire disturbance. J Exp Biol 2024; 227:jeb247114. [PMID: 38323432 DOI: 10.1242/jeb.247114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/31/2024] [Indexed: 02/08/2024]
Abstract
Metabolic physiology and animal behaviour are often considered to be linked, positively or negatively, according to either the performance or allocation models. Performance seems to predominate over allocation in natural systems, but the constraining environmental context may reveal allocation limitations to energetically expensive behaviours. Habitat disturbance, such as the large-scale fire that burnt wetlands of Biebrza National Park (NE Poland), degrades natural ecosystems. It arguably reduces food and shelter availability, modifies predator-prey interactions, and poses a direct threat for animal survival, such as that of the wetland specialist root vole Microtus oeconomus. We hypothesized that fire disturbance induces physiology-behaviour co-expression, as a consequence of changed environmental context. We repeatedly measured maintenance and exercise metabolism, and behavioural responses to the open field, in a root voles from post-fire and unburnt locations. Highly repeatable maintenance metabolism and distance moved during behavioural tests correlated positively, but relatively labile exercise metabolism did not covary with behaviour. At the same time, voles from a post-fire habitat had higher maintenance metabolism and moved shorter distances than voles from unburnt areas. We conclude there is a prevalence of the performance mechanism, but simultaneous manifestation of context-dependent allocation constraints of the physiology-behaviour covariation after disturbance. The last occurs at the within-individual level, indicating the significance of behavioural plasticity in the context of environmental disturbance.
Collapse
Affiliation(s)
- Karolina Iwińska
- University of Białystok Doctoral School in Exact and Natural Sciences, 15-245 Białystok, Poland
| | - Martyna Wirowska
- Adam Mickiewicz University, Department of Systematic Zoology, 61-614 Poznań, Poland
| | | | - Zbyszek Boratyński
- BIOPOLIS, CIBIO/InBio, Research Center in Biodiversity & Genetic Resources, University of Porto, 4485-661 Vairão, Portugal
| | - Paweł Solecki
- Faculty of Electronics and Information Technology, Warsaw University of Technology, 00-665 Warsaw, Poland
| | | | - Jan S Boratyński
- Mammal Research Institute, Polish Academy of Sciences, 17-230 Białowieża, Poland
| |
Collapse
|
2
|
Przybylska-Piech AS, Nowak A, Jefimow M. Warm spells in winter affect the equilibrium between winter phenotypes. J Therm Biol 2024; 120:103811. [PMID: 38382412 DOI: 10.1016/j.jtherbio.2024.103811] [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: 07/17/2023] [Revised: 01/10/2024] [Accepted: 01/26/2024] [Indexed: 02/23/2024]
Abstract
Each phenotype is a product of the interaction of the genes and the environment. Although winter phenotype in seasonal mammals is heritable, its development may be modified by external conditions. In today's world, global climate change and increasing frequency of unpredictable weather events may affect the dynamic equilibrium between phenotypes. We tested the effect of changes in ambient temperature during acclimation to short photoperiod on the development of winter phenotypes in three generations of Siberian hamsters (Phodopus sungorus). Based on seasonal changes in fur colour, body mass, and expression of daily torpor we distinguished three different winter phenotypes: responding, non-responding, and partially-responding to short photoperiod. We found that warm spells in winter can increase the proportion of non-responding individuals in the population, while stable winter conditions can increase photoresponsiveness among the offspring of non-responders. We conclude that the polymorphism of winter phenotype is an inherent characteristic of the Siberian hamster population but the development of winter phenotype is not fixed but rather a plastic response to the environmental conditions.
Collapse
Affiliation(s)
| | - Anna Nowak
- Department of Vertebrate Zoology and Ecology, Nicolaus Copernicus University, Toruń, Poland
| | - Małgorzata Jefimow
- Department of Animal Physiology and Neurobiology, Nicolaus Copernicus University Toruń, Poland.
| |
Collapse
|
3
|
Kennah JL, Peers MJL, Vander Wal E, Majchrzak YN, Menzies AK, Studd EK, Boonstra R, Humphries MM, Jung TS, Kenney AJ, Krebs CJ, Boutin S. Coat color mismatch improves survival of a keystone boreal herbivore: Energetic advantages exceed lost camouflage. Ecology 2023; 104:e3882. [PMID: 36208219 DOI: 10.1002/ecy.3882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 07/25/2022] [Indexed: 02/03/2023]
Abstract
Climate warming is causing asynchronies between animal phenology and environments. Mismatched traits, such as coat color change mismatched with snow, can decrease survival. However, coat change does not serve a singular adaptive benefit of camouflage, and alternate coat change functions may confer advantages that supersede mismatch costs. We found that mismatch reduced, rather than increased, autumn mortality risk of snowshoe hares in Yukon by 86.5% when mismatch occurred. We suggest that the increased coat insulation and lower metabolic rates of winter-acclimatized hares confer energetic advantages to white mismatched hares that reduce their mortality risk. We found that white mismatched hares forage 17-77 min less per day than matched brown hares between 0°C and -10°C, thus lowering their predation risk and increasing survival. We found no effect of mismatch on spring mortality risk, during which mismatch occurred at warmer temperatures, suggesting a potential temperature limit at which the costs of conspicuousness outweigh energetic benefits.
Collapse
Affiliation(s)
- Joanie L Kennah
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Michael J L Peers
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Eric Vander Wal
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Yasmine N Majchrzak
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Allyson K Menzies
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Emily K Studd
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Murray M Humphries
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Thomas S Jung
- Department of Environment, Government of Yukon, Whitehorse, Yukon, Canada.,Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Alice J Kenney
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Charles J Krebs
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
4
|
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]
|
5
|
Housing conditions modify seasonal changes in basal metabolism and body mass of the Siberian hamster, Phodopus sungorus. J Comp Physiol B 2022; 192:513-526. [PMID: 35348882 PMCID: PMC9197917 DOI: 10.1007/s00360-022-01434-9] [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: 12/15/2021] [Revised: 02/21/2022] [Accepted: 03/07/2022] [Indexed: 10/27/2022]
Abstract
Proper housing conditions are important aspects of animal welfare. Animals housed in enriched environments show less stereotypic behaviours than animals kept in barren cages. However, different types of cage enrichment may affect the results of experimental studies and hinder comparative analyses of animal physiology and behaviour. We investigated whether access to a running wheel, availability of nesting material, and pair housing affect basal metabolic rate (BMR) of Siberian hamsters (Phodopus sungorus) under various acclimation conditions. We used 70 adult hamsters (35 males and 35 females) divided into five groups housed under different cage conditions. All individuals experienced the same acclimation procedure: first a winter (L8:D16) then a summer (L16:D8) photoperiod, at air temperatures of first 20 °C then 7 °C under both photoperiods. We found that nesting material and pair housing did not affect hamster BMR, while access to a running wheel increased BMR and body mass regardless of photoperiod and ambient temperature. Thus, we suggest that cage enrichment should be applied with caution, especially in studies on energetics or thermoregulation, particularly in seasonal animals.
Collapse
|
6
|
Hayward L, Robertson CE, McClelland GB. Phenotypic plasticity to chronic cold exposure in two species of Peromyscus from different environments. J Comp Physiol B 2022; 192:335-348. [PMID: 34988665 DOI: 10.1007/s00360-021-01423-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 11/17/2021] [Accepted: 11/24/2021] [Indexed: 11/28/2022]
Abstract
Effective thermoregulation is important for mammals, particularly those that remain winter-active. Adjustments in thermoregulatory capacity in response to chronic cold can improve capacities for metabolic heat production (cold-induced maximal oxygen consumption, [Formula: see text]), minimize rates of heat loss (thermal conductance), or both. This can be challenging for animals living in chronically colder habitats where necessary resources (i.e., food, O2) for metabolic heat production are limited. Here we used lowland native white-footed mice (Peromyscus leucopus) and highland deer mice (P. maniculatus) native to 4300 m, to test the hypothesis that small winter-active mammals have evolved distinct cold acclimation responses to tailor their thermal physiology based on the energetic demands of their environment. We found that both species increased their [Formula: see text] after cold acclimation, associated with increases in brown adipose tissue mass and expression of uncoupling protein 1. They also broadened their thermoneutral zone to include lower ambient temperatures. This was accompanied by an increase in basal metabolic rate but only in white-footed mice, and neither species adjusted thermal conductance. Unique to highland deer mice was a mild hypothermia as ambient temperatures decreased, which reduced the gradient for heat loss, possibly to save energy in the chronically cold high alpine. These results highlight that thermal acclimation involves coordinated plasticity of numerous traits and suggest that small, winter-active mammals may adjust different aspects of their physiology in response to changing temperatures to best suit their energetic and thermoregulatory needs.
Collapse
Affiliation(s)
- Leah Hayward
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Cayleih E Robertson
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Grant B McClelland
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada.
| |
Collapse
|
7
|
Genoud M. The seasonal variation of basal metabolic rate is related to the expression of torpor among small mammals. J Therm Biol 2022; 104:103197. [DOI: 10.1016/j.jtherbio.2022.103197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 10/19/2022]
|
8
|
Playà‐Montmany N, González‐Medina E, Cabello‐Vergel J, Parejo M, Abad‐Gómez JM, Sánchez‐Guzmán JM, Villegas A, Masero JA. The thermoregulatory role of relative bill and leg surface areas in a Mediterranean population of Great tit ( Parus major). Ecol Evol 2021; 11:15936-15946. [PMID: 34824801 PMCID: PMC8601919 DOI: 10.1002/ece3.8263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/15/2021] [Accepted: 10/07/2021] [Indexed: 11/07/2022] Open
Abstract
There is growing evidence on the role of legs and bill as 'thermal windows' in birds coping with heat stress. However, there is a lack of empirical work examining the relationship between the relative bill and/or leg surface areas and key thermoregulatory traits such as the limits of the thermoneutral zone (TNZ) or the cooling efficiency at high temperatures. Here, we explored this relationship in a Mediterranean population of Great tit (Parus major) facing increasing thermal stress in its environment. The lower and upper critical limits of the TNZ were found to be 17.7 ± 1.6ºC and 34.5 ± 0.7°C, respectively, and the basal metabolic rate was 0.96 ± 0.12 ml O2 min-1 on average. The evaporative water loss (EWL) inflection point was established at 31.85 ± 0.27°C and was not significantly different from the value of the upper critical limit. No significant relationship was observed between the relative bill or tarsi size and TNZ critical limits, breadth, mass-independent VO2, or mass-independent EWL at any environmental temperature (from 10 to 40°C). However, Great tit males (but not females) with larger tarsi areas (a proxy of leg surface area) showed higher cooling efficiencies at 40°C. We found no support for the hypothesis that the bill surface area plays a significant role as a thermal window in Great tits, but the leg surface areas may play a role in males' physiological responses to high temperatures. On the one hand, we argue that the studied population occupies habitats with available microclimates and fresh water for drinking during summer, so active heat dissipation by EWL might be favored instead of dry heat loss through the bill surface. Conversely, male dominance behaviors could imply a greater dependence on cutaneous EWL through the upper leg surfaces as a consequence of higher exposure to harsh environmental conditions than faced by females.
Collapse
Affiliation(s)
- Núria Playà‐Montmany
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| | - Erick González‐Medina
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| | - Julián Cabello‐Vergel
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| | - Manuel Parejo
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| | - José M. Abad‐Gómez
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| | - Juan M. Sánchez‐Guzmán
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
- Ecology in the AnthropoceneAssociated Unit CSIC‐UEXFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| | - Auxiliadora Villegas
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
- Ecology in the AnthropoceneAssociated Unit CSIC‐UEXFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| | - José A. Masero
- Conservation Biology Research GroupFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
- Ecology in the AnthropoceneAssociated Unit CSIC‐UEXFacultad de CienciasUniversidad de ExtremaduraBadajozSpain
| |
Collapse
|
9
|
Swanson DL, Agin TJ, Zhang Y, Oboikovitz P, DuBay S. Metabolic Flexibility in Response to Within-Season Temperature Variability in House Sparrows. Integr Org Biol 2021; 2:obaa039. [PMID: 33791577 PMCID: PMC7810579 DOI: 10.1093/iob/obaa039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The climatic variability hypothesis (CVH) posits that more flexible phenotypes should provide a fitness advantage for organisms experiencing more variable climates. While typically applied across geographically separated populations, whether this principle applies across seasons or other conditions (e.g., open vs. sheltered habitats) which differ in climatic variability remains essentially unstudied. In north-temperate climates, climatic variability in winter usually exceeds that in summer, so extending the CVH to within-population seasonal variation predicts that winter phenotypes should be more flexible than summer phenotypes. We tested this prediction of the within-season extension of the CVH by acclimating summer and winter-collected house sparrows (Passer domesticus) to 24, 5, and -10°C and measuring basal metabolic rate (BMR) and summit metabolic rate (Msum = maximum cold-induced metabolic rate) before and after acclimation (Accl). To examine mechanistic bases for metabolic variation, we measured flight muscle and heart masses and citrate synthase and β-hydroxyacyl coA-dehydrogenase activities. BMR and Msum were higher for cold-acclimated than for warm-acclimated birds, and BMR was higher in winter than in summer birds. Contrary to our hypothesis of greater responses to cold Accl in winter birds, metabolic rates generally decreased over the Accl period for winter birds at all temperatures but increased at cold temperatures for summer birds. Flight muscle and heart masses were not significantly correlated with season or Accl treatment, except for supracoracoideus mass, which was lower at -10°C in winter, but flight muscle and heart masses were positively correlated with BMR and flight muscle mass was positively correlated with Msum. Catabolic enzyme activities were not clearly related to metabolic variation. Thus, our data suggest that predictions of the CVH may not be relevant when extended to seasonal temperature variability at the within-population scale. Indeed, these data suggest that metabolic rates are more prominently upregulated in summer than in winter in response to cold. Metabolic rates tended to decrease during Accl at all temperatures in winter, suggesting that initial metabolic rates at capture (higher in winter) influence metabolic Accl for captive birds.
Collapse
Affiliation(s)
- D L Swanson
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - T J Agin
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Y Zhang
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - P Oboikovitz
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - S DuBay
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
10
|
Przybylska-Piech AS, Wojciechowski MS, Jefimow M. Polymorphism of winter phenotype in Siberian hamster: consecutive litters do not differ in photoresponsiveness but prolonged acclimation to long photoperiod inhibits winter molt. Front Zool 2021; 18:11. [PMID: 33731152 PMCID: PMC7971963 DOI: 10.1186/s12983-021-00391-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/21/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The theory of delayed life history effects assumes that phenotype of adult individual results from environmental conditions experienced at birth and as juvenile. In seasonal environments, being born late in the reproductive season affects timing of puberty, body condition, longevity, and fitness. We hypothesized that late-born individuals are more prone to respond to short photoperiod (SP) than early born ones. We used Siberian hamsters Phodopus sungorus, a model species characterized by high polymorphism of winter phenotype. We experimentally distinguished the effect of litter order (first or third) from the effect of exposure to long photoperiod (LP) before winter (3 months or 5 months) by manipulating the duration of LP acclimation in both litters. We predicted that, irrespective of the litter order, individuals exposed to long photoperiod for a short time have less time to gather energy resources and consequently are more prone to developing energy-conserving phenotypes. To assess effect of litter order, duration of acclimation to long days, and phenotype on basal cost of living we measured basal metabolic rate (BMR) of hamsters. RESULTS Individuals born in third litters had faster growth rates and were bigger than individuals from first litters, but these differences vanished before transfer to SP. Litter order or duration of LP acclimation had no effects on torpor use or seasonal body mass changes, but prolonged acclimation to LP inhibited winter molting both in first and third litters. Moreover, individuals that did not molt had significantly higher BMR in SP than those which molted to white fur. Although one phenotype usually predominated within a litter, littermates were often heterogeneous. We also found that over 10% of individuals presented late response to short photoperiod. CONCLUSIONS Our data indicate that duration of postnatal exposure to LP may define propensity to photoresponsiveness, regardless of the litter in which animal was born. Existence of littermates presenting different phenotypes suggests a prudent reproductive strategy of investing into offspring of varied phenotypes, that might be favored depending on environmental conditions. This strategy could have evolved in response to living in stochastic environment.
Collapse
Affiliation(s)
- Anna S Przybylska-Piech
- Department of Vertebrate Zoology and Ecology, Nicolaus Copernicus University, Toruń, Poland.
| | - Michał S Wojciechowski
- Department of Vertebrate Zoology and Ecology, Nicolaus Copernicus University, Toruń, Poland
| | - Małgorzata Jefimow
- Department of Animal Physiology and Neurobiology, Nicolaus Copernicus University, Toruń, Poland
| |
Collapse
|
11
|
Phenotypic flexibility in heat production and heat loss in response to thermal and hydric acclimation in the zebra finch, a small arid-zone passerine. J Comp Physiol B 2020; 191:225-239. [PMID: 33070274 PMCID: PMC7819915 DOI: 10.1007/s00360-020-01322-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/21/2020] [Accepted: 09/29/2020] [Indexed: 11/28/2022]
Abstract
To maintain constant body temperature (Tb) over a wide range of ambient temperatures (Ta) endothermic animals require large amounts of energy and water. In hot environments, the main threat to endothermic homeotherms is insufficient water to supply that necessary for thermoregulation. We investigated flexible adjustment of traits related to thermoregulation and water conservation during acclimation to hot conditions or restricted water availability, or both, in the zebra finch, Taeniopygia guttata a small arid-zone passerine. Using indirect calorimetry, we measured changes in whole animal metabolic rate (MR), evaporative heat loss (EHL) and Tb before and after acclimation to 23 or 40 °C, with different availability of water. Additionally, we quantified changes in partitioning of EHL into respiratory and cutaneous avenues in birds exposed to 25 and 40 °C. In response to heat and water restriction zebra finches decreased MR, which together with unchanged EHL resulted in increased efficiency of evaporative heat loss. This facilitated more precise Tb regulation in heat-acclimated birds. Acclimation temperature and water availability had no effect on the partitioning of EHL into cutaneous or respiratory avenues. At 25 °C, cutaneous EHL accounted for ~ 60% of total EHL, while at 40 °C, its contribution decreased to ~ 20%. Consistent among-individual differences in MR and EHL suggest that these traits, provided that they are heritable, may be a subject to natural selection. We conclude that phenotypic flexibility in metabolic heat production associated with acclimation to hot, water-scarce conditions is crucial in response to changing environmental conditions, especially in the face of current and predicted climate change.
Collapse
|
12
|
Boratyński JS, Iwińska K, Szafrańska PA, Chibowski P, Bogdanowicz W. Continuous growth through winter correlates with increased resting metabolic rate but does not affect daily energy budgets due to torpor use. Curr Zool 2020; 67:131-145. [PMID: 33854531 PMCID: PMC8026158 DOI: 10.1093/cz/zoaa047] [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: 03/30/2020] [Accepted: 08/26/2020] [Indexed: 11/20/2022] Open
Abstract
Small mammals that are specialists in homeothermic thermoregulation reduce their self-maintenance costs of normothermy to survive the winter. By contrast, heterothermic ones that are considered generalists in thermoregulation can lower energy expenditure by entering torpor. It is well known that different species vary the use of their strategies to cope with harsh winters in temperate zones; however, little is still known about the intraspecific variation within populations and the associated external and internal factors. We hypothesized that yellow-necked mice Apodemus flavicollis decrease their resting metabolic rate (RMR) from autumn to winter, and then increase it during spring. However, since the alternative for seasonal reduction of RMR could be the development of heterothermy, we also considered the use of this strategy. We measured body mass (mb), RMR, and body temperature (Tb) of mice during 2 consecutive years. In the 1st year, mice decreased whole animal RMR in winter, but did not do so in the 2nd year. All mice entered torpor during the 2nd winter, whereas only a few did so during the first one. Mice showed a continuous increase of mb, which was steepest during the 2nd year. The relationship between RMR and mb varied among seasons and years most likely due to different mouse development stages. The mb gain at the individual level was correlated positively with RMR and heterothermy. This indicates that high metabolism in winter supports the growth of smaller animals, which use torpor as a compensatory mechanism. Isotope composition of mice hair suggests that in the 1st year they fed mainly on seeds, while in the 2nd, they likely consumed significant amounts of less digestible herbs. The study suggests that the use of specialist or generalist thermoregulatory strategies can differ with environmental variation and associated differences in developmental processes.
Collapse
Affiliation(s)
- Jan S Boratyński
- Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland
| | - Karolina Iwińska
- Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland.,Faculty of Biology, University of Białystok, Białystok, Poland
| | | | - Piotr Chibowski
- Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warszawa, Poland
| | - Wiesław Bogdanowicz
- Museum and Institute of Zoology, Polish Academy of Sciences, Warszawa, Poland
| |
Collapse
|
13
|
Jefimow M, Przybylska-Piech AS, Wojciechowski MS. Predictive and reactive changes in antioxidant defence system in a heterothermic rodent. J Comp Physiol B 2020; 190:479-492. [PMID: 32435827 PMCID: PMC7311498 DOI: 10.1007/s00360-020-01280-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 04/03/2020] [Accepted: 04/27/2020] [Indexed: 11/26/2022]
Abstract
Living in a seasonal environment requires periodic changes in animal physiology, morphology and behaviour. Winter phenotype of small mammals living in Temperate and Boreal Zones may differ considerably from summer one in multiple traits that enhance energy conservation or diminish energy loss. However, there is a considerable variation in the development of winter phenotype among individuals in a population and some, representing the non-responding phenotype (non-responders), are insensitive to shortening days and maintain summer phenotype throughout a year. Differences in energy management associated with the development of different winter phenotypes should be accompanied by changes in antioxidant defence capacity, leading to effective protection against oxidative stress resulting from increased heat production in winter. To test it, we analysed correlation of winter phenotypes of Siberian hamsters (Phodopus sungorus) with facultative non-shivering thermogenesis capacity (NST) and oxidative status. We found that in both phenotypes acclimation to winter-like conditions increased NST capacity and improved antioxidant defence resulting in lower oxidative stress (OS) than in summer, and females had always lower OS than males. Although NST capacity did not correlate with the intensity of OS, shortly after NST induction responders had lower OS than non-responders suggesting more effective mechanisms protecting from detrimental effects of reactive oxygen metabolites generated during rewarming from torpor. We suggest that seasonal increase in antioxidant defence is programmed endogenously to predictively prevent oxidative stress in winter. At the same time reactive upregulation of antioxidant defence protects against reactive oxygen species generated during NST itself. It suggests that evolution of winter phenotype with potentially harmful characteristics was counterbalanced by the development of protective mechanisms allowing for the maintenance of phenotypic adjustments to seasonally changing environment.
Collapse
Affiliation(s)
- Małgorzata Jefimow
- Department of Animal Physiology and Neurobiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, ul. Lwowska 1, 87-100, Toruń, Poland.
| | - 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
| | - Michał S Wojciechowski
- Department of Vertebrate Zoology and Ecology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, ul. Lwowska 1, 87-100, Toruń, Poland
| |
Collapse
|
14
|
Noakes MJ, McKechnie AE. Phenotypic flexibility of metabolic rate and evaporative water loss does not vary across a climatic gradient in an Afrotropical passerine bird. J Exp Biol 2020; 223:jeb220137. [PMID: 32165435 DOI: 10.1242/jeb.220137] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/02/2020] [Indexed: 12/30/2022]
Abstract
Small birds inhabiting northern temperate and boreal latitudes typically increase metabolic rates during cold winters or acclimation to low air temperatures (Taccl). Recent studies suggest considerable variation in patterns of seasonal metabolic acclimatization in birds from subtropical and tropical regions with milder winters, but there remains a dearth of acclimation studies investigating metabolic flexibility among lower-latitude birds. We used short-term thermal acclimation experiments to investigate phenotypic flexibility in basal metabolic rate (BMR), thermoneutral evaporative water loss (EWL) and summit metabolism (Msum) in three populations of white-browed sparrow-weavers (Plocepasser mahali) along a climatic and aridity gradient. We allocated individuals to one of three Taccl treatments (5, 20 and 35°C; n=11 per population per Taccl) for 28 days, and measured post-acclimation BMR, EWL and Msum using flow-through respirometry. Our data reveal the expected pattern of lower BMR and EWL (∼12% and 25% lower, respectively) in birds at Taccl=35°C compared with cooler Taccl treatments, as observed in previous acclimation studies on subtropical birds. We found no variation in the reaction norms of BMR and EWL among populations in response to acclimation, suggesting previously documented differences in seasonal BMR acclimatization are the result of phenotypic flexibility. In contrast to higher-latitude species, Msum did not significantly vary in response to thermal acclimation. These findings support the idea that factors other than enhancing cold tolerance may be driving patterns of metabolic variation in subtropical birds.
Collapse
Affiliation(s)
- Matthew J Noakes
- DST-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0001, South Africa
| | - Andrew E McKechnie
- DST-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0001, South Africa
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria 0001, South Africa
| |
Collapse
|
15
|
Norin T, Metcalfe NB. Ecological and evolutionary consequences of metabolic rate plasticity in response to environmental change. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180180. [PMID: 30966964 DOI: 10.1098/rstb.2018.0180] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Basal or standard metabolic rate reflects the minimum amount of energy required to maintain body processes, while the maximum metabolic rate sets the ceiling for aerobic work. There is typically up to three-fold intraspecific variation in both minimal and maximal rates of metabolism, even after controlling for size, sex and age; these differences are consistent over time within a given context, but both minimal and maximal metabolic rates are plastic and can vary in response to changing environments. Here we explore the causes of intraspecific and phenotypic variation at the organ, tissue and mitochondrial levels. We highlight the growing evidence that individuals differ predictably in the flexibility of their metabolic rates and in the extent to which they can suppress minimal metabolism when food is limiting but increase the capacity for aerobic metabolism when a high work rate is beneficial. It is unclear why this intraspecific variation in metabolic flexibility persists-possibly because of trade-offs with the flexibility of other traits-but it has consequences for the ability of populations to respond to a changing world. It is clear that metabolic rates are targets of selection, but more research is needed on the fitness consequences of rates of metabolism and their plasticity at different life stages, especially in natural conditions. This article is part of the theme issue 'The role of plasticity in phenotypic adaptation to rapid environmental change'.
Collapse
Affiliation(s)
- Tommy Norin
- 1 Institute of Biodiversity, Animal Health and Comparative Medicine, MVLS, University of Glasgow , Graham Kerr Building, Glasgow G12 8QQ , UK.,2 DTU Aqua: National Institute of Aquatic Resources , Kemitorvet Building 202, 2800 Kgs. Lyngby , Denmark
| | - Neil B Metcalfe
- 1 Institute of Biodiversity, Animal Health and Comparative Medicine, MVLS, University of Glasgow , Graham Kerr Building, Glasgow G12 8QQ , UK
| |
Collapse
|
16
|
Stawski C, Geiser F. Growing Up in a Changing Climate: How Temperature Affects the Development of Morphological, Behavioral and Physiological Traits of a Marsupial Mammal. Front Physiol 2020; 11:49. [PMID: 32116761 PMCID: PMC7028820 DOI: 10.3389/fphys.2020.00049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/21/2020] [Indexed: 01/14/2023] Open
Abstract
Climate change is likely to affect many mammalian phenotypes, yet little is known whether and how phenotypic plasticity is involved in responding to thermal challenges during mammalian development. We investigated the effect of continuous cold or warm exposure during development on morphological, behavioral, and functional variables of yellow-footed antechinus (Antechinus flavipes), a semelparous Australian marsupial mammal. Captive-bred young were exposed to two ambient temperatures (T a ), cold (17°C) or warm (25°C), once weaned. Treatments were reversed and metabolic rate (MR) measurements repeated after 2 months. We measured body mass weekly, activity continuously, and MRs over a range of T a once they were adults. Growth rate was similar in both groups, but was faster in males. Antechinus in the warm group were initially more active than the cold group and decreased activity when exposed to cold, whereas the cold group increased activity when exposed to warm. Interestingly, females changed their night-time activity when T a was changed, whereas males changed their daytime activity. MRs were originally lower in the warm group in comparison to the cold group for both sexes and increased slightly for females, but not for males, after being exposed to cold. After exposure to warm T a , the MRs of the cold group decreased significantly over the entire T a -range for both sexes. Our results reveal that temperatures experienced during development can influence behavioral and physiological traits in antechinus. Such phenotypic plasticity is vital for a species that within 1 year is dependent on a single breeding event and experiences a complete population turnover.
Collapse
Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia.,Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| |
Collapse
|
17
|
Noakes MJ, McKechnie AE. Reaction norms for heat tolerance and evaporative cooling capacity do not vary across a climatic gradient in a passerine bird. Comp Biochem Physiol A Mol Integr Physiol 2019; 236:110522. [PMID: 31278988 DOI: 10.1016/j.cbpa.2019.06.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/02/2019] [Accepted: 06/27/2019] [Indexed: 11/25/2022]
Abstract
There is increasing evidence for considerable phenotypic flexibility in endotherm thermal physiology, a phenomenon with far-reaching implications for the evolution of traits related to heat tolerance. Numerous studies have documented intraspecific variation in avian thermoregulatory traits, but few have revealed the shapes of thermoregulatory reaction norms or how these might vary among populations. We investigated phenotypic flexibility in the ability of a model Afrotropical passerine bird (the white-browed sparrow-weaver, Plocepasser mahali) to handle high air temperatures (Ta). We allocated birds from three sites varying by ~ 11 °C in mean daily summer maximum Ta to three acclimation temperature (Taccl) treatments (daytime Taccl ≈ 30 °C, 36 °C or 42 °C respectively; n ≈ 10 per site per Taccl). After an acclimation period of 30 days, heat tolerance and evaporative cooling capacity was quantified by exposing birds to progressively higher Ta until they approached severe hyperthermia (body temperature [Tb] = 44.5 °C; Ta range: 38-54 °C). We measured metabolic rate and evaporative water loss using open flow-through respirometry, and Tb using temperature-sensitive passive-integrated transponder tags. Hyperthermia threshold Ta (Ta,HT) was significantly higher and Tb significantly lower in birds acclimated to the hottest Taccl compared to those from milder acclimation treatments. Population (i.e., site of capture) was not a significant predictor of any thermoregulatory variables or hyperthermia threshold Ta (Ta,HT) after acclimation, revealing that the shape of reaction norms for heat tolerance and evaporative cooling capacity does not vary among these three populations.
Collapse
Affiliation(s)
- Matthew J Noakes
- DST-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
| | - Andrew E McKechnie
- DST-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa; South African Research Chair in Conservation Physiology, National Zoological Garden, South African National Biodiversity Institute, Pretoria, South Africa.
| |
Collapse
|
18
|
Boratyński Z, Koskela E, Mappes T, Mills SC, Mokkonen M. Maintenance costs of male dominance and sexually antagonistic selection in the wild. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13216] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Zbyszek Boratyński
- CIBIO/InBIOResearch Center in Biodiversity and Genetic ResourcesUniversity of Porto, Vairão Vairão Portugal
- Department of Biological and Environmental ScienceUniversity of Jyväskylä Jyväskylä Finland
| | - Esa Koskela
- Department of Biological and Environmental ScienceUniversity of Jyväskylä Jyväskylä Finland
| | - Tapio Mappes
- Department of Biological and Environmental ScienceUniversity of Jyväskylä Jyväskylä Finland
| | - Suzanne C. Mills
- Department of Biological and Environmental ScienceUniversity of Jyväskylä Jyväskylä Finland
- PSL Université Paris: EPHE‐UPVD‐CNRS, USR 3278 CRIOBE Papetoai, Moorea French Polynesia
- Laboratoire d'Excellence “CORAIL” Corail France
| | - Mikael Mokkonen
- Department of Biological and Environmental ScienceUniversity of Jyväskylä Jyväskylä Finland
- Department of Biological SciencesSimon Fraser University Burnaby British Columbia Canada
- Department of BiologyKwantlen Polytechnic University Surrey British Columbia Canada
| |
Collapse
|
19
|
McFarlane SE, Ålund M, Sirkiä PM, Qvarnström A. Difference in plasticity of resting metabolic rate - the proximate explanation to different niche breadth in sympatric Ficedula flycatchers. Ecol Evol 2018; 8:4575-4586. [PMID: 29760898 PMCID: PMC5938467 DOI: 10.1002/ece3.3987] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/24/2018] [Accepted: 02/09/2018] [Indexed: 12/11/2022] Open
Abstract
Variation in relative fitness of competing recently formed species across heterogeneous environments promotes coexistence. However, the physiological traits mediating such variation in relative fitness have rarely been identified. Resting metabolic rate (RMR) is tightly associated with life history strategies, thermoregulation, diet use, and inhabited latitude and could therefore moderate differences in fitness responses to fluctuations in local environments, particularly when species have adapted to different climates in allopatry. We work in a long‐term study of collared (Ficedula albicollis) and pied flycatchers (Ficedula hypoleuca) in a recent hybrid zone located on the Swedish island of Öland in the Baltic Sea. Here, we explore whether differences in RMR match changes in relative performance of growing flycatcher nestlings across environmental conditions using an experimental approach. The fitness of pied flycatchers has previously been shown to be less sensitive to the mismatch between the peak in food abundance and nestling growth among late breeders. Here, we find that pied flycatcher nestlings have lower RMR in response to higher ambient temperatures (associated with low food availability). We also find that experimentally relaxed nestling competition is associated with an increased RMR in this species. In contrast, collared flycatcher nestlings did not vary their RMR in response to these environmental factors. Our results suggest that a more flexible nestling RMR in pied flycatchers is responsible for the better adaptation of pied flycatchers to the typical seasonal changes in food availability experienced in this hybrid zone. Generally, subtle physiological differences that have evolved when species were in allopatry may play an important role to patterns of competition, coexistence, or displacements between closely related species in secondary contact.
Collapse
Affiliation(s)
- S Eryn McFarlane
- Animal Ecology/Ecology and Genetics Evolutionary Biology Centre Uppsala University Uppsala Sweden.,Present address: Institute of Evolutionary Biology University of Edinburgh Edinburgh UK
| | - Murielle Ålund
- Animal Ecology/Ecology and Genetics Evolutionary Biology Centre Uppsala University Uppsala Sweden
| | - Päivi M Sirkiä
- Finnish Museum of Natural History Zoology Unit University of Helsinki Helsinki Finland.,Section of Ecology Department of Biology University of Turku Turku Finland
| | - Anna Qvarnström
- Animal Ecology/Ecology and Genetics Evolutionary Biology Centre Uppsala University Uppsala Sweden
| |
Collapse
|
20
|
Shi LL, Fan WJ, Zhang JY, Zhao XY, Tan S, Wen J, Cao J, Zhang XY, Chi QS, Wang DH, Zhao ZJ. The roles of metabolic thermogenesis in body fat regulation in striped hamsters fed high-fat diet at different temperatures. Comp Biochem Physiol A Mol Integr Physiol 2017; 212:35-44. [PMID: 28711354 DOI: 10.1016/j.cbpa.2017.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/05/2017] [Accepted: 07/05/2017] [Indexed: 10/19/2022]
Abstract
The metabolic thermogenesis plays important roles in thermoregulation, and it may be also involved in body fat regulation. The thermogenesis of brown adipose tissue (BAT) is largely affected by ambient temperature, but it is unclear if the roles in body fat regulation are dependent on the temperature. In the present study, uncoupling protein 1 (ucp1)-based BAT thermogenesis, energy budget and body fat content were examined in the striped hamsters fed high fat diet (HF) at cold (5°C) and warm (30°C) temperatures. The effect of 2, 4-dinitrophenol (DNP), a chemical uncoupler, on body fat was also examined. The striped hamsters showed a notable increase in body fat following the HF feeding at 21°C. The increased body fat was markedly elevated at 30°C, but was significantly attenuated at 5°C compared to that at 21°C. The hamsters significantly increased energy intake at 5°C, but consumed less food at 30°C relative to those at 21°C. Metabolic thermogenesis, indicated by basal metabolic rate, UCP1 expression and/or serum triiodothyronine levels, significantly increased at 5°C, but decreased at 30°C compared to that at 21°C. A significant decrease in body fat content was observed in DNP-treated hamsters relative to the controls. These findings suggest that the roles of metabolic thermogenesis in body fat regulation largely depend on ambient temperature. The cold-induced enhancement of BAT thermogenesis may contribute the decreased body fat, resulting in a lean mass. Instead, the attenuation of BAT thermogenesis at the warm may result in notable obesity.
Collapse
Affiliation(s)
- Lu-Lu Shi
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Wei-Jia Fan
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Ji-Ying Zhang
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Xiao-Ya Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Song Tan
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jing Wen
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jing Cao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Xue-Ying Zhang
- State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
| | - Qing-Sheng Chi
- State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
| | - De-Hua Wang
- State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
| | - Zhi-Jun Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China.
| |
Collapse
|
21
|
Boratyński JS, Jefimow M, Wojciechowski MS. Melatonin attenuates phenotypic flexibility of energy metabolism in a photoresponsive mammal, the Siberian hamster. ACTA ACUST UNITED AC 2017; 220:3154-3161. [PMID: 28606897 DOI: 10.1242/jeb.159517] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/07/2017] [Indexed: 01/27/2023]
Abstract
The duration of melatonin (MEL) secretion conveys information about day length and initiates a cascade of seasonal phenotypic adjustments in photoresponsive mammals. With shortening days, animals cease reproduction, minimize energy expenditure, enhance thermoregulatory capacity and adjust functioning of the hypothalamic-pituitary-adrenal (HPA) axis to match the winter increase in energy demands. Within each season, stress plays an important role in the flexible adjustments of a phenotype to environmental perturbations. Recent studies have shown that thermal reaction norms of energy metabolism were narrower in winter-acclimated Siberian hamsters, Phodopus sungorus We tested the hypothesis that physiological changes occurring in response to prolonged MEL signals, including changes in the secretion of stress hormones, are responsible for the seasonal decrease in phenotypic flexibility of energy metabolism in photoresponsive mammals. To quantify reaction norms for basal metabolic rate (BMR) and cortisol (CORT) secretion, male Siberian hamsters maintained at a long (16 h:8 h light:dark) photoperiod were acclimated repeatedly for 12 days to 10 and 28°C. As predicted, the phenotypic flexibility of BMR decreased when animals were supplemented with MEL. However, at the same time, mean CORT concentration and the reaction norm for its secretion in response to changes in acclimation temperature increased. These results suggest that decreased sensitivity of HPA axis to CORT signal, rather than changes in CORT level itself, is responsible for the decreased phenotypic flexibility in photoresponsive species. Our results suggest that decreased phenotypic flexibility in winter, together with increased stress hormone secretion, make photosensitive species more vulnerable to climate change.
Collapse
Affiliation(s)
- Jan S Boratyński
- Department of Animal Physiology, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
| | - Małgorzata Jefimow
- Department of Animal Physiology, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
| | - Michał S Wojciechowski
- Department of Vertebrate Zoology, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
| |
Collapse
|
22
|
Waterhouse MD, Sjodin B, Ray C, Erb L, Wilkening J, Russello MA. Individual-based analysis of hair corticosterone reveals factors influencing chronic stress in the American pika. Ecol Evol 2017. [PMID: 28649323 PMCID: PMC5478070 DOI: 10.1002/ece3.3009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Glucocorticoids are often measured in wildlife to assess physiological responses to environmental or ecological stress. Hair, blood, saliva, or fecal samples are generally used depending on the timescale of the stress response being investigated and species‐specific considerations. Here, we report the first use of hair samples to measure long‐term corticosterone levels in the climate‐sensitive American pika (Ochotona princeps). We validated an immunoassay‐based measurement of corticosterone extracted from hair samples and compared corticosterone estimates obtained from plasma, hair, and fecal samples of nine pikas. To demonstrate an ecological application of this technique, we characterized physiological stress in 49 pikas sampled and released at eight sites along two elevational transects. Microclimate variation was measured at each site using both ambient and subsurface temperature sensors. We used an information theoretic approach to compare support for linear, mixed‐effects models relating corticosterone estimates to microclimate, body size, and sex. Corticosterone was measured accurately in pika hair samples after correcting for the influence of sample mass on corticosterone extraction efficiency. Hair‐ and plasma‐based estimates of corticosterone were weakly correlated. The best‐supported model suggested that corticosterone was lower in larger, male pikas, and at locations with higher ambient temperatures in summer. Our results are consistent with a general negative relationship between body mass and glucocorticoid concentration observed across mammalian species, attributed to the higher mass‐specific metabolic rates of smaller bodied animals. The higher corticosterone levels in female pikas likely reflected the physiological demands of reproduction, as observed in a wide array of mammalian species. Additionally, we establish the first direct physiological evidence for thermal stress in the American pika through nonlethal sampling of corticosterone. Interestingly, our data suggest evidence for cold stress likely induced during the summer molting period. This technique should provide a useful tool to researchers wishing to assess chronic stress in climate‐sensitive mammals.
Collapse
Affiliation(s)
| | - Bryson Sjodin
- Department of Biology University of British Columbia Kelowna BC Canada
| | - Chris Ray
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology University of Colorado Boulder CO USA
| | - Liesl Erb
- Departments of Biology and Environmental Studies Warren Wilson College Asheville NC USA
| | - Jennifer Wilkening
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology University of Colorado Boulder CO USA
| | | |
Collapse
|
23
|
Swanson DL, McKechnie AE, Vézina F. How low can you go? An adaptive energetic framework for interpreting basal metabolic rate variation in endotherms. J Comp Physiol B 2017; 187:1039-1056. [PMID: 28401293 DOI: 10.1007/s00360-017-1096-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/13/2017] [Accepted: 04/06/2017] [Indexed: 11/24/2022]
Abstract
Adaptive explanations for both high and low body mass-independent basal metabolic rate (BMR) in endotherms are pervasive in evolutionary physiology, but arguments implying a direct adaptive benefit of high BMR are troublesome from an energetic standpoint. Here, we argue that conclusions about the adaptive benefit of BMR need to be interpreted, first and foremost, in terms of energetics, with particular attention to physiological traits on which natural selection is directly acting. We further argue from an energetic perspective that selection should always act to reduce BMR (i.e., maintenance costs) to the lowest level possible under prevailing environmental or ecological demands, so that high BMR per se is not directly adaptive. We emphasize the argument that high BMR arises as a correlated response to direct selection on other physiological traits associated with high ecological or environmental costs, such as daily energy expenditure (DEE) or capacities for activity or thermogenesis. High BMR thus represents elevated maintenance costs required to support energetically demanding lifestyles, including living in harsh environments. BMR is generally low under conditions of relaxed selection on energy demands for high metabolic capacities (e.g., thermoregulation, activity) or conditions promoting energy conservation. Under these conditions, we argue that selection can act directly to reduce BMR. We contend that, as a general rule, BMR should always be as low as environmental or ecological conditions permit, allowing energy to be allocated for other functions. Studies addressing relative reaction norms and response times to fluctuating environmental or ecological demands for BMR, DEE, and metabolic capacities and the fitness consequences of variation in BMR and other metabolic traits are needed to better delineate organismal metabolic responses to environmental or ecological selective forces.
Collapse
Affiliation(s)
- David L Swanson
- Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, SD, 57069, USA.
| | - Andrew E McKechnie
- Department of Zoology and Entomology, DST-NRF Centre of Excellence at the Percy FitzPatrick Institute, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - François Vézina
- Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, QC, Canada.,Groupe de recherche sur les environnements nordiques BORÉAS, Centre d'Études Nordiques, Centre de la Science de la Biodiversité du Québec, Rimouski, QC, Canada
| |
Collapse
|
24
|
Boratyński JS, Jefimow M, Wojciechowski MS. Individual Differences in the Phenotypic Flexibility of Basal Metabolic Rate in Siberian Hamsters Are Consistent on Short- and Long-Term Timescales. Physiol Biochem Zool 2016; 90:139-152. [PMID: 28277958 DOI: 10.1086/689870] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Basal metabolic rate (BMR) correlates with the cost of life in endothermic animals. It usually differs consistently among individuals in a population, but it may be adjusted in response to predictable or unpredictable changes in the environment. The phenotypic flexibility of BMR is considered an adaptation to living in a stochastic environment; however, whether it is also repeatable it is still unexplored. Assuming that variations in phenotypic flexibility are evolutionarily important, we hypothesized that they are consistently different among individuals. We predicted that not only BMR but also its flexibility in response to changes in ambient temperature (Ta) are repeatable on short- and long-term timescales. To examine this, we acclimated Siberian hamsters (Phodopus sungorus) for 100 d to winterlike and then to summerlike conditions, and after each acclimation we exposed them interchangeably to 10° and 28°C for 14 d. The difference in BMR measured after each exposure defined an individual's phenotypic flexibility (ΔBMR). BMR was repeatable within and among seasons. It was also flexible in both seasons, but in winter this flexibility was lower in individuals responding to seasonal changes than in nonresponding ones. When we accounted for individual responsiveness, the repeatability of ΔBMR was significant in winter (τ = 0.48, P = 0.01) and in summer (τ = 0.55, P = 0.005). Finally, the flexibility of BMR in response to changes in Ta was also repeatable on a long-term timescale, that is, among seasons (τ = 0.31, P = 0.008). Our results indicate the evolutionary importance of the phenotypic flexibility of energy metabolism and suggest that it may be subject to selection.
Collapse
|