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Pacioni C, Bushuev A, Sentís M, Kerimov A, Ivankina E, Lens L, Strubbe D. Metabolic adjustments to winter severity in two geographically separated great tit (Parus major) populations. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:410-420. [PMID: 38369854 DOI: 10.1002/jez.2790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/30/2023] [Accepted: 01/24/2024] [Indexed: 02/20/2024]
Abstract
Understanding the potential limits placed on organisms by their ecophysiology is crucial for predicting their responses to varying environmental conditions. A main hypothesis for explaining avian thermoregulatory mechanisms is the aerobic capacity model, which posits a positive correlation between basal (basal metabolic rate [BMR]) and summit (Msum) metabolism. Most evidence for this hypothesis, however, comes from interspecific comparisons, and the ecophysiological underpinnings of avian thermoregulatory capacities hence remain controversial. Indeed, studies have traditionally relied on between-species comparisons, although, recently, there has been a growing recognition of the importance of intraspecific variation in ecophysiological responses. Therefore, here, we focused on great tits (Parus major), measuring BMR and Msum during winter in two populations from two different climates: maritime-temperate (Gontrode, Belgium) and continental (Zvenigorod, Russia). We tested for the presence of intraspecific geographical variation in metabolic rates and assessed the predictions following the aerobic capacity model. We found that birds from the maritime-temperate climate (Gontrode) showed higher BMR, whereas conversely, great tits from Zvenigorod showed higher levels of Msum. Within each population, our data did not fully support the aerobic capacity model's predictions. We argued that the decoupling of BMR and Msum observed may be caused by different selective forces acting on these metabolic rates, with birds from the continental-climate Zvenigorod population facing the need to conserve energy for surviving long winter nights (by keeping their BMR at low levels) while simultaneously being able to generate more heat (i.e., a high Msum) to withstand cold spells.
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Affiliation(s)
- Cesare Pacioni
- Terrestrial Ecology Unit, Ghent University, Ghent, Belgium
| | - Andrey Bushuev
- Department of Vertebrate Zoology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Marina Sentís
- Terrestrial Ecology Unit, Ghent University, Ghent, Belgium
| | - Anvar Kerimov
- Department of Vertebrate Zoology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Elena Ivankina
- S.N. Skadovsky Zvenigorod Biological Station, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Luc Lens
- Terrestrial Ecology Unit, Ghent University, Ghent, Belgium
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Persson E, Ó Cuív C, Nord A. Thermoregulatory consequences of growing up during a heatwave or a cold snap in Japanese quail. J Exp Biol 2024; 227:jeb246876. [PMID: 38073475 PMCID: PMC10906667 DOI: 10.1242/jeb.246876] [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: 10/11/2023] [Accepted: 12/06/2023] [Indexed: 01/26/2024]
Abstract
Changes in environmental temperature during development can affect growth, metabolism and temperature tolerance of the offspring. We know little about whether such changes remain to adulthood, which is important to understand the links between climate change, development and fitness. We investigated whether phenotypic consequences of the thermal environment in early life remained in adulthood in two studies on Japanese quail (Coturnix japonica). Birds were raised under simulated heatwave, cold snap or control conditions, from hatching until halfway through the growth period, and then in common garden conditions until reproductively mature. We measured biometric and thermoregulatory [metabolic heat production (MHP), evaporative water and heat loss (EWL, EHL) and body temperature] responses to variation in submaximal air temperature at the end of the thermal acclimation period and in adulthood. Warm birds had lower MHP than control birds at the end of the thermal acclimation period and, in the warmest temperature studied (40°C), also had higher evaporative cooling capacity compared with controls. No analogous responses were recorded in cold birds, although they had higher EWL than controls in all but the highest test temperature. None of the effects found at the end of the heatwave or cold snap period remained until adulthood. This implies that chicks exposed to higher temperatures could be more prepared to counter heat stress as juveniles but that they do not enjoy any advantages of such developmental conditions when facing high temperatures as adults. Conversely, cold temperature does not seem to confer any priming effects in adolescence.
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Affiliation(s)
- Elin Persson
- Lund University, Department of Biology, Section for Evolutionary Ecology, Sölvegatan 37, SE-223 63 Lund, Sweden
| | - Ciarán Ó Cuív
- Lund University, Department of Biology, Section for Evolutionary Ecology, Sölvegatan 37, SE-223 63 Lund, Sweden
| | - Andreas Nord
- Lund University, Department of Biology, Section for Evolutionary Ecology, Sölvegatan 37, SE-223 63 Lund, Sweden
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Swanson DL, Stager M, Vézina F, Liu JS, McKechnie AE, Amirkhiz RG. Evidence for a maintenance cost for birds maintaining highly flexible basal, but not summit, metabolic rates. Sci Rep 2023; 13:8968. [PMID: 37268715 DOI: 10.1038/s41598-023-36218-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 05/31/2023] [Indexed: 06/04/2023] Open
Abstract
Reversible phenotypic flexibility allows organisms to better match phenotypes to prevailing environmental conditions and may produce fitness benefits. Costs and constraints of phenotypic flexibility may limit the capacity for flexible responses but are not well understood nor documented. Costs could include expenses associated with maintaining the flexible system or with generating the flexible response. One potential cost of maintaining a flexible system is an energetic cost reflected in the basal metabolic rate (BMR), with elevated BMR in individuals with more flexible metabolic responses. We accessed data from thermal acclimation studies of birds where BMR and/or Msum (maximum cold-induced metabolic rate) were measured before and after acclimation, as a measure of metabolic flexibility, to test the hypothesis that flexibility in BMR (ΔBMR), Msum (ΔMsum), or metabolic scope (Msum - BMR; ΔScope) is positively correlated with BMR. When temperature treatments lasted at least three weeks, three of six species showed significant positive correlations between ΔBMR and BMR, one species showed a significant negative correlation, and two species showed no significant correlation. ΔMsum and BMR were not significantly correlated for any species and ΔScope and BMR were significantly positively correlated for only one species. These data suggest that support costs exist for maintaining high BMR flexibility for some bird species, but high flexibility in Msum or metabolic scope does not generally incur elevated maintenance costs.
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Affiliation(s)
- David L Swanson
- Department of Biology, University of South Dakota, Vermillion, SD, USA.
| | - Maria Stager
- Department of Biology, University of Massachusetts, Amherst, MA, USA
| | - François Vézina
- Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, QC, Canada
| | - Jin-Song Liu
- School of Life and Environmental Sciences, Wenzhou University, Wenzhou, China
| | - Andrew E McKechnie
- DST‑NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, South Africa
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, P.O. Box 754, Pretoria, 0001, South Africa
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Pacioni C, Sentís M, Kerimov A, Bushuev A, Lens L, Strubbe D. Seasonal variation in thermoregulatory capacity of three closely related Afrotropical Estrildid finches introduced to Europe. J Therm Biol 2023; 113:103534. [PMID: 37055139 DOI: 10.1016/j.jtherbio.2023.103534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/21/2023] [Accepted: 02/21/2023] [Indexed: 03/07/2023]
Abstract
A species' potential geographical range is largely determined by how the species responds physiologically to its changing environment. It is therefore crucial to study the physiological mechanisms that species use to maintain their homeothermy in order to address biodiversity conservation challenges, such as the success of invasions of introduced species. The common waxbill Estrilda astrild, the orange-cheeked waxbill E. melpoda, and the black-rumped waxbill E. troglodytes are small Afrotropical passerines that have established invasive populations in regions where the climate is colder than in their native ranges. As a result, they are highly suitable species for studying potential mechanisms for coping with a colder and more variable climate. Here, we investigated the magnitude and direction of seasonal variation in their thermoregulatory traits, such as basal (BMR), summit (Msum) metabolic rates and thermal conductance. We found that, from summer to autumn, their ability to resist colder temperatures increased. This was not related to larger body masses or higher BMR and Msum, but instead, species downregulated BMR and Msum toward the colder season, suggesting energy conservation mechanisms to increase winter survival. BMR and Msum were most strongly correlated with temperature variation in the week preceding the measurements. Common waxbill and black-rumped waxbill, whose native ranges encompass the highest degree of seasonality, showed the most flexibility in metabolic rates (i.e., stronger downregulation toward colder seasons). This ability to adjust thermoregulatory traits, combined with increased cold tolerance, may facilitate their establishment in areas characterized by colder winters and less predictable climates.
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Broggi J, Nilsson JÅ. Individual response in body mass and basal metabolism to the risks of predation and starvation in passerines. J Exp Biol 2023; 226:286531. [PMID: 36628936 PMCID: PMC10086538 DOI: 10.1242/jeb.244744] [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: 07/01/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023]
Abstract
Wintering energy management in small passerines has focused on the adaptive regulation of the daily acquisition of energy reserves within a starvation-predation trade-off framework. However, the possibility that the energetic cost of living, i.e. basal metabolic rate (BMR), is being modulated as part of the management energy strategy has been largely neglected. Here, we addressed this possibility by experimentally exposing captive great tits (Parus major) during winter to two consecutive treatments of increased starvation and predation risk for each individual bird. Body mass and BMR were measured prior to and after each week-long treatment. We predicted that birds should be lighter but with a higher metabolic capacity (higher BMR) as a response to increased predation risk, and that birds should increase internal reserves while reducing their cost of living (lower BMR) when exposed to increased starvation risk. Wintering great tits kept a constant body mass independently of a week-long predation or starvation treatment. However, great tits reduced the cost of living (lower BMR) when exposed to the starvation treatment, while BMR remained unaffected by the predation treatment. Energy management in wintering small birds partly relies on BMR regulation, which challenges the current theoretical framework based on body mass regulation.
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Affiliation(s)
- Juli Broggi
- Department of Biology, Section of Evolutionary Ecology, University of Lund, S-223 62 Lund, Sweden.,Estación Biológica de Doñana (CSIC), Av. Américo Vespucio 26, 41092 Sevilla, Spain.,Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales - CSIC, C/José Gutiérrez Abascal 2, Madrid 28006, Spain
| | - Jan-Åke Nilsson
- Department of Biology, Section of Evolutionary Ecology, University of Lund, S-223 62 Lund, Sweden
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Garant R, Tobalske BW, Sassi NB, van Staaveren N, Widowski T, Powers DR, Harlander-Matauschek A. Wing-feather loss in white-feathered laying hens decreases pectoralis thickness but does not increase risk of keel bone fracture. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220155. [PMID: 35719889 PMCID: PMC9198519 DOI: 10.1098/rsos.220155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/24/2022] [Indexed: 05/03/2023]
Abstract
Feather loss in domestic chickens can occur due to wear and tear, disease or bird-to-bird pecking. Flight feather loss may decrease wing use, cause pectoral muscle loss and adversely impact the keel bone to which these muscles anchor. Feather loss and muscle weakness are hypothesized risk factors for keel bone fractures that are reported in up to 98% of chickens. We used ultrasound to measure changes in pectoral muscle thickness and X-rays to assess keel bone fracture prevalence following symmetric clipping of primary and secondary feathers in white- and brown-feathered birds. Four and six weeks after flight feather clipping, pectoralis thickness decreased by approximately 5%, while lower leg thickness increased by approximately 5% in white-feathered birds. This pectoralis thickness decrease may reflect wing disuse followed by muscle atrophy, while the increased leg thickness may reflect increased bipedal locomotion. The lack of effect on muscle thickness in brown-feathered hens was probably due to their decreased tendency for aerial locomotion. Finally, pectoralis thickness was not associated with keel bone fractures in either white- or brown-feathered birds. This suggests that the white-feathered strain was more sensitive to feather loss. Future prevention strategies should focus on birds most susceptible to muscle loss associated with flight feather damage.
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Affiliation(s)
- Renée Garant
- Department of Animal Biosciences, University of Guelph, 50 Stone Road E, Guelph, ON N1G 2W1, Canada
| | - Bret W. Tobalske
- Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Neila Ben Sassi
- Department of Animal Biosciences, University of Guelph, 50 Stone Road E, Guelph, ON N1G 2W1, Canada
| | - Nienke van Staaveren
- Department of Animal Biosciences, University of Guelph, 50 Stone Road E, Guelph, ON N1G 2W1, Canada
| | - Tina Widowski
- Department of Animal Biosciences, University of Guelph, 50 Stone Road E, Guelph, ON N1G 2W1, Canada
| | - Donald R. Powers
- Department of Biology, George Fox University, 414N Meridian Street, Newberg, OR 97132, USA
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Broggi J, Hohtola E, Koivula K, Rytkönen S, Nilsson JÅ. Prehatching temperatures drive inter-annual cohort differences in great tit metabolism. Oecologia 2022; 198:619-627. [PMID: 35174406 PMCID: PMC8956552 DOI: 10.1007/s00442-022-05126-7] [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: 09/11/2021] [Accepted: 01/25/2022] [Indexed: 11/14/2022]
Abstract
Basal metabolic rate (BMR) constitutes the lowest metabolic rate in a resting animal and is, therefore, considered to reflect the energetic cost of maintenance in endotherms. BMR is a reversible plastic trait that changes with environmental and ecological circumstances, albeit being heritable and susceptible to selection. Inter-individual variation within populations of small birds is substantial, and while many of the drivers of such variation have been identified, many remain unexplained. We studied winter BMR variation of juveniles over a 15-year period in a wild population of great tits Parus major at the northern border of their distribution. BMR during winter consistently changed between years, even after controlling for environmental factors, suggestive of a non-reversible developmental plasticity shaping the adult metabolic phenotype. BMR in cohorts of wintering great tits varied among winters as a response to minimum ambient temperatures experienced early in life, during the prehatching period. This developmental plasticity might be adaptive if temperatures experienced by growing embryos would metabolically prime them to an environment that they will likely encounter in future life. However, in line with a more unpredictable future climate, the risk of phenotype-environment mismatch is likely to lead to certain cohorts being poorly adapted to prevailing winter conditions, resulting in wider annual fluctuations in population size.
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Affiliation(s)
- Juli Broggi
- Department of Biology, Section of Evolutionary Ecology, University of Lund, 223 62, Lund, Sweden.
- Estación Biológica de Doñana (CSIC), Av. Américo Vespucio 26, 41092, Sevilla, Spain.
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales - CSIC, C/José Gutiérrez Abascal 2, 28006, Madrid, Spain.
| | - Esa Hohtola
- Ecology and Genetics Research Unit, Faculty of Science, University of Oulu, P.O. Box 8000, FI-90014, Oulu, Finland
| | - Kari Koivula
- Ecology and Genetics Research Unit, Faculty of Science, University of Oulu, P.O. Box 8000, FI-90014, Oulu, Finland
| | - Seppo Rytkönen
- Ecology and Genetics Research Unit, Faculty of Science, University of Oulu, P.O. Box 8000, FI-90014, Oulu, Finland
| | - Jan-Åke Nilsson
- Department of Biology, Section of Evolutionary Ecology, University of Lund, 223 62, Lund, Sweden
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Le Pogam A, O’Connor RS, Love OP, Drolet J, Régimbald L, Roy G, Laplante MP, Berteaux D, Tam A, Vézina F. Snow Buntings Maintain Winter-Level Cold Endurance While Migrating to the High Arctic. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.724876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Arctic breeding songbirds migrate early in the spring and can face winter environments requiring cold endurance throughout their journey. One such species, the snow bunting (Plectrophenax nivalis), is known for its significant thermogenic capacity. Empirical studies suggest that buntings can indeed maintain winter cold acclimatization into the migratory and breeding phenotypes when kept captive on their wintering grounds. This capacity could be advantageous not only for migrating in a cold environment, but also for facing unpredictable Arctic weather on arrival and during preparation for breeding. However, migration also typically leads to declines in the sizes of several body components linked to metabolic performance. As such, buntings could also experience some loss of cold endurance as they migrate. Here, we aimed to determine whether free-living snow buntings maintain a cold acclimatized phenotype during spring migration. Using a multi-year dataset, we compared body composition (body mass, fat stores, and pectoralis muscle thickness), oxygen carrying capacity (hematocrit) and metabolic performance (thermogenic capacity – Msum and maintenance energy expenditure – BMR) of birds captured on their wintering grounds (January–February, Rimouski, QC, 48°N) and during pre-breeding (April–May) in the Arctic (Alert, NU, 82°). Our results show that body mass, fat stores and Msum were similar between the two stages, while hematocrit and pectoralis muscle thickness were lower in pre-breeding birds than in wintering individuals. These results suggest that although tissue degradation during migration may affect flight muscle size, buntings are able to maintain cold endurance (i.e., Msum) up to their Arctic breeding grounds. However, BMR was higher during pre-breeding than during winter, suggesting higher maintenance costs in the Arctic.
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Oboikovitz P, Swanson DL. Seasonal metabolic flexibility is correlated with microclimate variation in horned larks and house sparrows. Curr Zool 2021; 68:199-210. [PMID: 35355948 PMCID: PMC8962734 DOI: 10.1093/cz/zoab037] [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] [Received: 01/30/2021] [Accepted: 04/28/2021] [Indexed: 11/28/2022] Open
Abstract
Maximum and minimum metabolic rates in birds are flexible traits and such flexibility can be advantageous in variable climates. The climatic variability hypothesis (CVH) posits that more variable climates should result in greater metabolic flexibility for geographically distinct populations. Whether the CVH applies to sympatric species occupying microclimates differing in variability is unknown. Microclimates of open habitats are likely more variable than those of sheltered habitats. If the CVH extends to microclimates, we expect birds from open habitats to show greater flexibility than those from sheltered habitats. To test this extension of the CVH, we compared seasonal variation in microclimates and metabolic rates for sympatric horned larks Eremophila alpestris, which occupy open habitats, and house sparrows Passer domesticus, which occupy sheltered habitats. We measured operative temperature (Te, an integrative measure of the thermal environment), summit metabolic rate (Msum, maximal cold-induced metabolic rate), and basal metabolic rate (BMR, minimal maintenance metabolic rate) in summer and winter. For both winter and summer, daily minimum Te was similar between open and sheltered habitats but maximum Te was higher for open habitats. Winter microclimates, however, were colder for open than for sheltered habitats after accounting for convective differences. Both species increased Msum in winter, but seasonal Msum flexibility was greater for larks (43%) than for sparrows (31%). Winter increases in BMR were 92.5% and 11% for larks and sparrows, respectively, with only the former attaining statistical significance. Moreover, species * season interactions in general linear models for whole-organism metabolic rates were significant for BMR and showed a similar, although not significant, pattern for Msum, with greater seasonal metabolic flexibility in horned larks than in house sparrows. These results suggest that extending the CVH to sympatric bird species occupying different microclimates may be valid.
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Affiliation(s)
- Paige Oboikovitz
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - David L Swanson
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
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Le Pogam A, O'Connor RS, Love OP, Petit M, Régimbald L, Vézina F. Coping with the worst of both worlds: Phenotypic adjustments for cold acclimatization benefit northward migration and arrival in the cold in an Arctic‐breeding songbird. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13793] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Audrey Le Pogam
- 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
| | - Ryan S. O'Connor
- 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
| | - Oliver P. Love
- Department of Integrative Biology University of Windsor Windsor ON Canada
| | - Magali Petit
- 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
| | - Lyette Régimbald
- Département de biologie, chimie et géographie Université du Québec à Rimouski Rimouski QC Canada
| | - 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
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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.
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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
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Le Pogam A, Love OP, Régimbald L, Dubois K, Hallot F, Milbergue M, Petit M, O'Connor RS, Vézina F. Wintering Snow Buntings Elevate Cold Hardiness to Extreme Levels but Show No Changes in Maintenance Costs. Physiol Biochem Zool 2021; 93:417-433. [PMID: 33048603 DOI: 10.1086/711370] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractResident temperate passerines adjust their phenotypes to cope with winter constraints, with peak performance in metabolic traits typically occurring during the coldest months. However, it is sparsely known whether cold-adapted northern species make similar adjustments when faced with variable seasonal environments. Life in near-constant cold could be associated with limited flexibility in traits underlying cold endurance. We investigated this by tracking individual physiological changes over five consecutive winters in snow buntings (Plectrophenax nivalis), an Arctic-breeding migratory passerine typically confronted with nearly constant cold. Buntings were held in an outdoor aviary and exposed to seasonal temperature variation typical of temperate zone climates. We measured phenotypic changes in body composition (body, fat, and lean mass, pectoralis muscle thickness), oxygen transport capacity (hematocrit), metabolic performance (basal metabolic rate [BMR] and summit metabolic rate [Msum]), thermogenic endurance (time to reach Msum), and cold tolerance (temperature at Msum). Snow buntings showed flexibility in functions underlying thermogenic capacity and cold endurance comparable to that observed in temperate resident passerines wintering at similar latitudes. Specifically, they increased body mass (13%), fat mass (246%), hematocrit (23%), pectoralis muscle thickness (8%), and Msum (27%). We also found remarkable cold tolerance in these birds, with individuals reaching Msum in helox at temperatures equivalent to less than -90°C in air. However, in contrast with resident temperate passerines, lean mass decreased by 12%, and there was no clear increase in maintenance costs (BMR). Our results show that the flexibility of traits underlying thermal acclimatization in a cold-adapted northern species is comparable to that of temperate resident species living at lower latitudes and is therefore not limited by life in near-constant cold.
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Oswald KN, Lee ATK, Smit B. Seasonal metabolic adjustments in an avian evolutionary relict restricted to mountain habitat. J Therm Biol 2020; 95:102815. [PMID: 33454043 DOI: 10.1016/j.jtherbio.2020.102815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 11/12/2020] [Accepted: 12/12/2020] [Indexed: 10/22/2022]
Abstract
For endotherms, maintaining body temperature during cold winters is energetically costly.Greater increase in winter maximum thermogenic capacity (Msum) has typically been correlated with improved cold tolerance. However, seasonal studies have shown equivocal direction change in basal metabolic rate (BMR) in winter, perhaps explained by latitude or phylogeny. We examined seasonal metabolic responses in the Cape rockjumper (Chaetops frenatus; "rockjumper"), a range-restricted mountain bird. We hypothesized that, given their mountain habitat preference, rockjumpers would be physiologically specialized for cooler air temperatures compared to other subtropical passerines. We measured body condition (using the ratio of Mb/tarsus), BMR, and Msum, in wild-living rockjumpers during winter and summer (n = 12 adults in winter -- 4 females, 8 males; n = 12 adults in summer -- 6 females, 6 males). We found birds had lesser BMR and thermal conductance, and greater Msum and body condition, in winter compared to summer. These changes may help rockjumpers conserve energy in winter while still allowing birds to produce more metabolic heat during the coldest air temperatures. When compared with existing data on avian seasonal metabolic adjustments, rockjumper BMR fit general patterns observed in passerines, but their Msum was low compared with other members of the oscine Passeriformes. These patterns may be explained by the narrow temperature range of their habitat not requiring cold-adjustment, or perhaps by their basal placement within passerine phylogeny. Further work on the physiological phenotypic plasticity in habitat specialists across different latitudinal zones and taxa is needed to better understand the relationship between metabolism, habitat, and phylogeny.
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Affiliation(s)
- Krista N Oswald
- Department of Zoology and Entomology, Rhodes University, Makhanda, 6139, South Africa; Department of Zoology, Nelson Mandela University, Port Elizabeth, 6031, South Africa.
| | - Alan T K Lee
- Fitzpatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Cape Town, 7701, South Africa; Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa
| | - Ben Smit
- Department of Zoology and Entomology, Rhodes University, Makhanda, 6139, South Africa; Department of Zoology, Nelson Mandela University, Port Elizabeth, 6031, South Africa
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Robertson JK, Mastromonaco GF, Burness G. Social hierarchy reveals thermoregulatory trade-offs in response to repeated stressors. J Exp Biol 2020; 223:jeb229047. [PMID: 32967999 DOI: 10.1242/jeb.229047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/09/2020] [Indexed: 11/20/2022]
Abstract
Coping with stressors can require substantial energetic investment, and when resources are limited, such investment can preclude simultaneous expenditure on other biological processes. Among endotherms, energetic demands of thermoregulation can also be immense, yet our understanding of whether a stress response is sufficient to induce changes in thermoregulatory investment is limited. Using the black-capped chickadee as a model species, we tested a hypothesis that stress-induced changes in surface temperature (Ts), a well-documented phenomenon across vertebrates, stem from trade-offs between thermoregulation and stress responsiveness. Because social subordination is known to constrain access to resources in this species, we predicted that Ts and dry heat loss of social subordinates, but not social dominants, would fall under stress exposure at low ambient temperatures (Ta), and rise under stress exposure at high Ta, thus permitting a reduction in total energetic expenditure toward thermoregulation. To test our predictions, we exposed four social groups of chickadees to repeated stressors and control conditions across a Ta gradient (n=30 days/treatment/group), whilst remotely monitoring social interactions and Ts Supporting our hypothesis, we show that: (1) social subordinates (n=12), who fed less than social dominants and alone experienced stress-induced mass-loss, displayed significantly larger changes in Ts following stress exposure than social dominants (n=8), and (2) stress-induced changes in Ts significantly increased heat conservation at low Ta and heat dissipation at high Ta among social subordinates alone. These results suggest that chickadees adjust their thermoregulatory strategies during stress exposure when resources are limited by ecologically relevant processes.
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Affiliation(s)
- Joshua K Robertson
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada K9L 0G2
- Department of Wildlife and Science, Toronto Zoo, Scarborough, ON, Canada M1B 5K7
| | | | - Gary Burness
- Department of Biology, Trent University, Peterborough, ON, Canada K9L 0G2
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15
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Archer LC, Hutton SA, Harman L, Poole WR, Gargan P, McGinnity P, Reed TE. Metabolic traits in brown trout ( Salmo trutta) vary in response to food restriction and intrinsic factors. CONSERVATION PHYSIOLOGY 2020; 8:coaa096. [PMID: 33093959 PMCID: PMC7566963 DOI: 10.1093/conphys/coaa096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/15/2020] [Accepted: 09/30/2020] [Indexed: 06/11/2023]
Abstract
Metabolic rates vary hugely within and between populations, yet we know relatively little about factors causing intraspecific variation. Since metabolic rate determines the energetic cost of life, uncovering these sources of variation is important to understand and forecast responses to environmental change. Moreover, few studies have examined factors causing intraspecific variation in metabolic flexibility. We explore how extrinsic environmental conditions and intrinsic factors contribute to variation in metabolic traits in brown trout, an iconic and polymorphic species that is threatened across much of its native range. We measured metabolic traits in offspring from two wild populations that naturally show life-history variation in migratory tactics (one anadromous, i.e. sea-migratory, one non-anadromous) that we reared under either optimal food or experimental conditions of long-term food restriction (lasting between 7 and 17 months). Both populations showed decreased standard metabolic rates (SMR-baseline energy requirements) under low food conditions. The anadromous population had higher maximum metabolic rate (MMR) than the non-anadromous population, and marginally higher SMR. The MMR difference was greater than SMR and consequently aerobic scope (AS) was higher in the anadromous population. MMR and AS were both higher in males than females. The anadromous population also had higher AS under low food compared to optimal food conditions, consistent with population-specific effects of food restriction on AS. Our results suggest different components of metabolic rate can vary in their response to environmental conditions, and according to intrinsic (population-background/sex) effects. Populations might further differ in their flexibility of metabolic traits, potentially due to intrinsic factors related to life history (e.g. migratory tactics). More comparisons of populations/individuals with divergent life histories will help to reveal this. Overall, our study suggests that incorporating an understanding of metabolic trait variation and flexibility and linking this to life history and demography will improve our ability to conserve populations experiencing global change.
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Affiliation(s)
- Louise C Archer
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Ireland
- Environmental Research Institute, University College Cork, Lee Road, Cork T23 XE10, Ireland
| | - Stephen A Hutton
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Ireland
- Environmental Research Institute, University College Cork, Lee Road, Cork T23 XE10, Ireland
| | - Luke Harman
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Ireland
- Environmental Research Institute, University College Cork, Lee Road, Cork T23 XE10, Ireland
| | - W Russell Poole
- Marine Institute, Furnace, Newport, Co. Mayo F28 PF65, Ireland
| | - Patrick Gargan
- Inland Fisheries Ireland, 3044 Lake Drive, Citywest Business Campus, Dublin D24 Y265, Ireland
| | - Philip McGinnity
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Ireland
- Marine Institute, Furnace, Newport, Co. Mayo F28 PF65, Ireland
| | - Thomas E Reed
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Ireland
- Environmental Research Institute, University College Cork, Lee Road, Cork T23 XE10, Ireland
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16
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Stager M, Senner NR, Tobalske BW, Cheviron ZA. Body temperature maintenance acclimates in a winter-tenacious songbird. J Exp Biol 2020; 223:jeb221853. [PMID: 32376710 DOI: 10.1242/jeb.221853] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/04/2020] [Indexed: 12/16/2022]
Abstract
Flexibility in heat generation and dissipation mechanisms provides endotherms the ability to match their thermoregulatory strategy with external demands. However, the degree to which these two mechanisms account for seasonal changes in body temperature regulation is little explored. Here, we present novel data on the regulation of avian body temperature to investigate how birds alter mechanisms of heat production and heat conservation to deal with variation in ambient conditions. We subjected dark-eyed juncos (Junco hyemalis) to chronic cold acclimations of varying duration and subsequently quantified their metabolic rates, thermal conductance and ability to maintain normothermia. Cold-acclimated birds adjusted traits related to both heat generation (increased summit metabolic rate) and heat conservation (decreased conductance) to improve their body temperature regulation. Increases in summit metabolic rate occurred rapidly, but plateaued after 1 week of cold exposure. In contrast, changes to conductance occurred only after 9 weeks of cold exposure. Thus, the ability to maintain body temperature continued to improve throughout the experiment, but the mechanisms underlying this improvement changed through time. Our results demonstrate the ability of birds to adjust thermoregulatory strategies in response to thermal cues and reveal that birds may combine multiple responses to meet the specific demands of their environments.
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Affiliation(s)
- Maria Stager
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Nathan R Senner
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Bret W Tobalske
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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17
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Noakes MJ, Karasov WH, McKechnie AE. Seasonal variation in body composition in an Afrotropical passerine bird: increases in pectoral muscle mass are, unexpectedly, associated with lower thermogenic capacity. J Comp Physiol B 2020; 190:371-380. [PMID: 32189062 DOI: 10.1007/s00360-020-01273-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 02/22/2020] [Accepted: 03/02/2020] [Indexed: 11/26/2022]
Abstract
Phenotypic flexibility in avian metabolic rates and body composition have been well-studied in high-latitude species, which typically increase basal metabolic rate (BMR) and summit metabolism (Msum) when acclimatized to winter conditions. Patterns of seasonal metabolic acclimatization are more variable in lower-latitude birds that experience milder winters, with fewer studies investigating adjustments in avian organ and muscle masses in the context of metabolic flexibility in these regions. We quantified seasonal variation (summer vs winter) in the masses of organs and muscles frequently associated with changes in BMR (gizzard, intestines and liver) and Msum (heart and pectoral muscles), in white-browed sparrow-weavers (Plocepasser mahali). We also measured pectoral muscle thickness using a portable ultrasound system to determine whether we could non-lethally estimate muscle size. A concurrent study measured seasonal changes in BMR and Msum in the same population of sparrow-weavers, but different individuals. There was no seasonal variation in the dry masses of the gizzard, intestines or liver of sparrow-weavers, and during the same period, BMR did not vary seasonally. We found significantly higher heart (~ 18% higher) and pectoral muscle (~ 9% higher) dry mass during winter, although ultrasound measurements did not detect seasonal changes in pectoral muscle size. Despite winter increases in pectoral muscle mass, Msum was ~ 26% lower in winter compared to summer. To the best of our knowledge, this is the first study to report an increase in avian pectoral muscle mass but a concomitant decrease in thermogenic capacity.
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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
| | - William H Karasov
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI, USA
| | - 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, South African National Biodiversity Institute, Pretoria, South Africa.
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18
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Noakes MJ, McKechnie AE. Seasonal Metabolic Acclimatization Varies in Direction and Magnitude among Years in Two Arid-Zone Passerines. Physiol Biochem Zool 2020; 93:140-152. [DOI: 10.1086/707679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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19
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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'.
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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
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20
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Vézina F, Cornelius Ruhs E, O'Connor ES, Le Pogam A, Régimbald L, Love OP, Jimenez AG. Consequences of being phenotypically mismatched with the environment: rapid muscle ultrastructural changes in cold-shocked black-capped chickadees ( Poecile atricapillus). Am J Physiol Regul Integr Comp Physiol 2019; 318:R274-R283. [PMID: 31823671 DOI: 10.1152/ajpregu.00203.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Phenotypic flexibility has received considerable attention in the last decade; however, whereas many studies have reported amplitude of variation in phenotypic traits, much less attention has focused on the rate at which traits can adjust in response to sudden changes in the environment. We investigated whole animal and muscle phenotypic changes occurring in black-capped chickadees (Poecile atricapillus) acclimated to cold (-5°C) and warm (20°C) temperatures in the first 3 h following a 15°C temperature drop (over 3 h). Before the temperature change, cold-acclimated birds were consuming 95% more food, were carrying twice as much body fat, and had 23% larger pectoralis muscle fiber diameters than individuals kept at 20°C. In the 3 h following the temperature drop, these same birds altered their pectoralis muscle ultrastructure by increasing the number of capillaries per fiber area and the number of nuclei per millimeter of fiber by 22%, consequently leading to a 22% decrease in myonuclear domain (amount of cytoplasm serviced per nucleus), whereas no such changes were observed in the warm-acclimated birds. To our knowledge, this is the first demonstration of such a rapid adjustment in muscle fiber ultrastructure in vertebrates. These results support the hypothesis that chickadees maintaining a cold phenotype are better prepared than warm-phenotype individuals to respond to a sudden decline in temperature, such as what may be experienced in their natural wintering environment.
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Affiliation(s)
- François Vézina
- Départment de Biologie, Chimie et Géographie, Groupe de Recherche sur les Environnements Nordiques BORÉAS, Centre d'études Nordiques, Centre de la Science de la Biodiversité du Québec Université du Québec à Rimouski, Québec, Canada
| | - Emily Cornelius Ruhs
- Départment de Biologie, Chimie et Géographie, Groupe de Recherche sur les Environnements Nordiques BORÉAS, Centre d'études Nordiques, Centre de la Science de la Biodiversité du Québec Université du Québec à Rimouski, Québec, Canada
| | - Erin S O'Connor
- Department of Biology, Colgate University, Hamilton, New York
| | - Audrey Le Pogam
- Départment de Biologie, Chimie et Géographie, Groupe de Recherche sur les Environnements Nordiques BORÉAS, Centre d'études Nordiques, Centre de la Science de la Biodiversité du Québec Université du Québec à Rimouski, Québec, Canada
| | - Lyette Régimbald
- Départment de Biologie, Chimie et Géographie, Groupe de Recherche sur les Environnements Nordiques BORÉAS, Centre d'études Nordiques, Centre de la Science de la Biodiversité du Québec Université du Québec à Rimouski, Québec, Canada
| | - Oliver P Love
- Department of Integrative Biology, University of Windsor, Ontario, Canada
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21
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Sabat P, Bozinovic F, Contreras-Ramos C, Nespolo RF, Newsome SD, Quirici V, Maldonado K, Peña-Villalobos I, Ramirez-Otarola N, Sanchez-Hernandez JC. The interplay between ambient temperature and salt intake affects oxidative status and immune responses in a ubiquitous Neotropical passerine, the rufous-collared sparrow. Comp Biochem Physiol A Mol Integr Physiol 2019; 234:50-59. [DOI: 10.1016/j.cbpa.2019.04.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 03/30/2019] [Accepted: 04/18/2019] [Indexed: 12/28/2022]
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22
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Swanson DL, King MO, Culver W, Zhang Y. Within-winter flexibility in muscle and heart lipid transport and catabolism in passerine birds. J Comp Physiol B 2019; 189:451-462. [PMID: 31076837 DOI: 10.1007/s00360-019-01218-8] [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: 01/17/2019] [Revised: 04/11/2019] [Accepted: 04/22/2019] [Indexed: 11/25/2022]
Abstract
Small birds in cold climates may show within-winter metabolic flexibility to match metabolic capacities to prevailing weather conditions. This flexibility may occur over periods of days to weeks, but the underlying mechanisms for such flexibility are not well understood. Because lipids are the primary fuel for sustained thermogenesis, we examined whether lipid transport and catabolism can mediate within-winter metabolic flexibility in two small temperate-zone wintering passerine birds, dark-eyed juncos (Junco hyemalis) and house sparrows (Passer domesticus). We used simple and multiple regression analyses to test for correlations of several lipid transporters in pectoralis muscle (plasma membrane-bound and cytosolic fatty acid-binding proteins, FABP; fatty acyl translocase, FAT/CD36) and regulatory enzymes (carnitine acyl transferase, CPT; β-hydroxyacyl CoA dehydrogenase, HOAD) in pectoralis and heart with short-term (ST, 0-7 days), medium-term (MT, 14-30 days) and long-term (LT, 30-year mean daily and extreme minimum temperatures, day of winter season) temperature variables. We hypothesized negative correlations between these regulators and temperature variables. Juncos showed negative correlations for FABPs with ST or MT temperature variables, but other lipid transporters and regulatory enzymes showed positive correlations with ST or MT temperatures for juncos, suggesting no consistent pathway-wide response to within-winter temperatures. LT temperature variables showed several significant associations with lipid transporters and enzymes for juncos, but also not in consistent directions. House sparrows showed the expected negative correlations with LT temperatures for FABPpm, but positive correlations with temperature variables for FABPc, CPT and HOAD. Different species-specific patterns of variation and the absence of consistent pathway-wide responses to temperature suggest that the lipid transport and catabolism pathway is not a uniform mediator of within-winter metabolic flexibility among small birds.
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Affiliation(s)
- David L Swanson
- Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, SD, 57069, USA.
| | - Marisa O King
- Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, SD, 57069, USA
- Department of Biology, Grand View University, 1200 Grandview Ave, Des Moines, IA, 50316, USA
| | - William Culver
- Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, SD, 57069, USA
- Department of Wildlife, Humboldt State University, Arcata, CA, 95521, USA
- Virginia-Maryland College of Veterinary Medicine, 205 Duck Pond Drive, Blacksburg, VA, 24061, USA
| | - Yufeng Zhang
- Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, SD, 57069, USA
- School of Health Studies, University of Memphis, Memphis, TN, 38152, USA
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Broggi J, Nilsson JF, Koivula K, Hohtola E, Nilsson JÅ. Mass or pace? Seasonal energy management in wintering boreal passerines. Oecologia 2019; 189:339-351. [PMID: 30617630 PMCID: PMC6394691 DOI: 10.1007/s00442-018-04332-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 12/20/2018] [Indexed: 01/24/2023]
Abstract
Research on winter energy management in small vertebrates has focused on the regulation of body mass (BM) within a framework of starvation-predation trade-off. Winter-acclimatized birds exhibit a seasonal increase in both BM and basal metabolic rate (BMR), although the patterns of co-variation between the two traits remain unknown. We studied this co-variation in three different species of wild titmice, great, blue and willow tits, originating from two boreal regions at different latitudes. Seasonal change in BM and BMR was inter-dependent, particularly in the great tit; however, by contrast, no seasonal change was observed in the willow tit. BMR changed non-linearly in concert with BM with a peak in midwinter for both blue and great tits, whereas such non-linear pattern in willow tit was opposite and independent of BM. Surprisingly, BMR appears to be more sensitive to ambient temperatures than BM in all three species studied. Energy management is a multifaceted strategy that cannot be fully understood without considering reserve levels and energy expenditure simultaneously. Thus, our study indicates that the prevailing conceptual framework based on variation in BM alone is insufficient to understand seasonal energy management in small wintering passerines.
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Affiliation(s)
- Juli Broggi
- Section of Evolutionary Ecology, Department of Biology, University of Lund, 223 62, Lund, Sweden. .,Estación Biológica de Doñana (CSIC), Av. Americo Vespucio 26, 41092, Seville, Spain.
| | - Johan F Nilsson
- Section of Evolutionary Ecology, Department of Biology, University of Lund, 223 62, Lund, Sweden
| | - Kari Koivula
- Department of Ecology and Genetics, University of Oulu, P.O. Box 3000, 90014, Oulu, Finland
| | - Esa Hohtola
- Department of Ecology and Genetics, University of Oulu, P.O. Box 3000, 90014, Oulu, Finland
| | - Jan-Åke Nilsson
- Section of Evolutionary Ecology, Department of Biology, University of Lund, 223 62, Lund, Sweden
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24
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Pakanen VM, Ahonen E, Hohtola E, Rytkönen S. Northward expanding resident species benefit from warming winters through increased foraging rates and predator vigilance. Oecologia 2018; 188:991-999. [PMID: 30357531 PMCID: PMC6244859 DOI: 10.1007/s00442-018-4271-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 10/08/2018] [Indexed: 11/30/2022]
Abstract
Species distributions shift northwards due to climate change, but the ecological mechanisms allowing range expansions are not fully understood. Most studies have concentrated on breeding seasons, but winter warming may also be important. Wintering distributions are restricted by food availability and temperature, which may also interact. Foraging in cold conditions requires adaptations as individuals have to be efficient in foraging, while staying warm and vigilant for predators. When the ambient temperature declines, foraging rates should be reduced due to increased time spent on warming behaviours. In addition, predator vigilance should decline, because more time has to be invested in foraging. Cold weather should limit northward expanding southern species in particular, while northern species should perform better in cold conditions. We tested this by studying temperature responses (between 0 and − 35 °C) among wintering birds at feeders. We compared foraging behaviours of two northward expanding southern species, the great tit (Parus major) and the blue tit (Cyanistes caeruleus) to a northern species, the willow tit (Poecile montanus). Foraging rate and vigilance decreased, and warming behaviour increased when temperatures declined. Importantly, the performance in these traits was poorer in the southern species compared to the willow tit. Furthermore, the response to decreasing temperatures in foraging rates and warming behaviour was stronger in the great tits than willow tits. As the winters become warmer, these mechanisms should increase wintering success of southern species wintering at high latitudes, and lead to higher survival, increased population growth, and consequent range expansion.
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Affiliation(s)
- Veli-Matti Pakanen
- Ecology and Genetics Research Unit, University of Oulu, PO Box 3000, 90014, Oulu, Finland.
| | - Eveliina Ahonen
- Ecology and Genetics Research Unit, University of Oulu, PO Box 3000, 90014, Oulu, Finland
| | - Esa Hohtola
- Ecology and Genetics Research Unit, University of Oulu, PO Box 3000, 90014, Oulu, Finland
| | - Seppo Rytkönen
- Ecology and Genetics Research Unit, University of Oulu, PO Box 3000, 90014, Oulu, Finland
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25
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Large muscles are beneficial but not required for improving thermogenic capacity in small birds. Sci Rep 2018; 8:14009. [PMID: 30228279 PMCID: PMC6143541 DOI: 10.1038/s41598-018-32041-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 08/23/2018] [Indexed: 01/03/2023] Open
Abstract
It is generally assumed that small birds improve their shivering heat production capacity by developing the size of their pectoralis muscles. However, some studies have reported an enhancement of thermogenic capacity in the absence of muscle mass variation between seasons or thermal treatments. We tested the hypothesis that an increase in muscle mass is not a prerequisite for improving avian thermogenic capacity. We measured basal (BMR) and summit (Msum) metabolic rates of black capped chickadees (Poecile atricapillus) acclimated to thermoneutral (27 °C) and cold (-10 °C) temperatures and obtained body composition data from dissections. Cold acclimated birds consumed 44% more food, and had 5% and 20% higher BMR and Msum, respectively, compared to individuals kept at thermoneutrality. However, lean dry pectoralis and total muscle mass did not differ between treatments, confirming that the improvement of thermogenic capacity did not require an increase in skeletal muscle mass. Nevertheless, within temperature treatments, Msum was positively correlated with the mass of all measured muscles, including the pectoralis. Therefore, for a given acclimation temperature individuals with large muscles do benefit from muscle size in term of heat production but improving thermogenic capacity during cold acclimation likely requires an upregulation of cell functions.
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26
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Latimer CE, Cooper SJ, Karasov WH, Zuckerberg B. Does habitat fragmentation promote climate-resilient phenotypes? OIKOS 2018. [DOI: 10.1111/oik.05111] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Christopher E. Latimer
- Dept of Forest and Wildlife Ecology; Univ. of Wisconsin-Madison; 226 Russell Labs 1630 Linden Drive Madison WI 53706 USA
| | | | - William H. Karasov
- Dept of Forest and Wildlife Ecology; Univ. of Wisconsin-Madison; 226 Russell Labs 1630 Linden Drive Madison WI 53706 USA
| | - Benjamin Zuckerberg
- Dept of Forest and Wildlife Ecology; Univ. of Wisconsin-Madison; 226 Russell Labs 1630 Linden Drive Madison WI 53706 USA
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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.
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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
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Jäger J, Schradin C, Pillay N, Rimbach R. Active and explorative individuals are often restless and excluded from studies measuring resting metabolic rate: Do alternative metabolic rate measures offer a solution? Physiol Behav 2017; 174:57-66. [PMID: 28283463 DOI: 10.1016/j.physbeh.2017.02.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/23/2017] [Accepted: 02/15/2017] [Indexed: 10/20/2022]
Abstract
It has often been proposed that bolder, more explorative or more active individuals also have a higher resting metabolic rate (RMR), indicating metabolic costs of these personality types. However, such individuals might often be restless and thus excluded from RMR datasets, leading to a significant sampling bias. We tested (1) whether such a bias occurs when animals are measured for a relatively common but short time period of 3h, and if so, (2) whether alternative measures of metabolic rate, that allow the incorporation of non-resting individuals, would reveal associations between metabolism and personality. For this, we studied free-living individuals of the African striped mouse (Rhabdomys pumilio) both during the moist season (N=25 individuals) with high food availability and the dry season (N=48 individuals) with low food availability. We assessed variation in the latency to explore a novel object, and the time spent active and time spent in the centre of a neutral arena. We examined links between personality and (i) RMR and (ii) four alternative metabolic rate (MR) metrics: average MR, highest MR, lowest MR and span of MR. Twenty-nine percent of the measured individuals had to be excluded from our RMR study because they remained restless during respirometry trials. Striped mice showed a behavioural syndrome where fast explorers also spent more time in centre and more time active than slow explorers. Individuals that did not rest during respirometry trials were faster explorers and in the moist season, they were also more active and spent more time in the centre than individuals that rested. We found no relationship between RMR and the behavioural syndrome, which might be due to the exclusion of individuals with a certain behavioural type, leaving a subset of compliant individuals. In the moist season, we found positive relationships between the behavioural syndrome and span of MR and lowest MR. In the dry season, low food availability may mask links between the behavioural syndrome and alternative MR measures due to reduced overall activity in striped mice. Our study demonstrated the importance to consider personality when measuring RMR and suggests that some alternative MRs may be useful to examine relationships between metabolism and personality when it is impossible to measure individuals over extended time periods.
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Affiliation(s)
- Jörg Jäger
- University of the Witwatersrand, School of Animal, Plant & Environmental Sciences, Private Bag 3, WITS, 2050 Johannesburg, South Africa
| | - Carsten Schradin
- University of the Witwatersrand, School of Animal, Plant & Environmental Sciences, Private Bag 3, WITS, 2050 Johannesburg, South Africa; IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France
| | - Neville Pillay
- University of the Witwatersrand, School of Animal, Plant & Environmental Sciences, Private Bag 3, WITS, 2050 Johannesburg, South Africa
| | - Rebecca Rimbach
- University of the Witwatersrand, School of Animal, Plant & Environmental Sciences, Private Bag 3, WITS, 2050 Johannesburg, South Africa.
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29
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Petit M, Clavijo-Baquet S, Vézina F. Increasing Winter Maximal Metabolic Rate Improves Intrawinter Survival in Small Birds. Physiol Biochem Zool 2017; 90:166-177. [DOI: 10.1086/689274] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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30
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Noakes MJ, Wolf BO, McKechnie AE. Seasonal Metabolic Acclimatization Varies in Direction and Magnitude among Populations of an Afrotropical Passerine Bird. Physiol Biochem Zool 2017; 90:178-189. [DOI: 10.1086/689030] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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31
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Briga M, Verhulst S. Individual variation in metabolic reaction norms over ambient temperature causes low correlation between basal and standard metabolic rate. J Exp Biol 2017; 220:3280-3289. [DOI: 10.1242/jeb.160069] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/04/2017] [Indexed: 12/19/2022]
Abstract
Basal metabolic rate (BMR) is often assumed to be indicative of the energy turnover at ambient temperatures (Ta) below the thermoneutral zone (SMR), but this assumption has remained largely untested. Using a new statistical approach, we quantified the consistency in nocturnal metabolic rate across a temperature range in zebra finches (n=3,213 measurements on 407 individuals) living permanently in eight outdoor aviaries. Foraging conditions were either benign or harsh, and body mass and mass-adjusted BMRm and SMRm were lower in individuals living in a harsh foraging environment. The correlation between SMRm at different Tas was high (r=0.91), independent of foraging environment, showing that individuals are consistently ranked according to their SMRm. However, the correlations between BMRm and SMRm were always lower (average: 0.29; range: 0<r<0.50), in particular in the benign foraging environment. Variation in metabolic response to lower Ta at least in part reflected differential body temperature (Tb) regulation: early morning Tb was lower at low Ta's, and more so in individuals with a weaker metabolic response to lower Ta's. Our findings have implications for the use of BMR in the estimation of time-energy budgets and comparative analyses: we suggest that the use of metabolic rates at ecologically relevant ambient temperatures, such as the easily tractable SMR, will be more informative than the use of BMR as a proxy for energy turnover.
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Affiliation(s)
- Michael Briga
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
- Present address: Department of Biology, University of Turku, Vesilinnantie 5, 20014 Turku, Finland
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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32
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Rimbach R, Pillay N, Schradin C. Both thyroid hormone levels and resting metabolic rate decrease in African striped mice when food availability decreases. ACTA ACUST UNITED AC 2016; 220:837-843. [PMID: 27994044 DOI: 10.1242/jeb.151449] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/12/2016] [Indexed: 01/13/2023]
Abstract
In response to variation in food availability and ambient temperature (Ta), many animals show seasonal adaptations in their physiology. Laboratory studies showed that thyroid hormones are involved in the regulation of metabolism, and their regulatory function is especially important when the energy balance of an individual is compromised. However, little is known about the relationship between thyroid hormones and metabolism in free-living animals and animals inhabiting seasonal environments. Here, we studied seasonal changes in triiodothyronine (T3) levels, resting metabolic rate (RMR) and two physiological markers of energy balance (blood glucose and ketone bodies) in 61 free-living African striped mice (Rhabdomys pumilio) that live in an semi-arid environment with food shortage during the dry season. We predicted a positive relationship between T3 levels and RMR. Further, we predicted higher T3 levels, blood glucose levels and RMR, but lower ketone body concentrations, during the moist season when food availability is high compared with summer when food availability is low. RMR and T3 levels were negatively related in the moist season but not in the dry season. Both RMR and T3 levels were higher in the moist than in the dry season, and T3 levels increased with increasing food availability. In the dry season, blood glucose levels were lower but ketone body concentrations were higher, indicating a change in substrate use. Seasonal adjustments in RMR and T3 levels permit a reduction of energy expenditure when food is scarce, and reflect an adaptive response to reduced food availability in the dry season.
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Affiliation(s)
- Rebecca Rimbach
- University of the Witwatersrand, School of Animal, Plant & Environmental Sciences, Private Bag 3, WITS 2050, Johannesburg, South Africa
| | - Neville Pillay
- University of the Witwatersrand, School of Animal, Plant & Environmental Sciences, Private Bag 3, WITS 2050, Johannesburg, South Africa
| | - Carsten Schradin
- University of the Witwatersrand, School of Animal, Plant & Environmental Sciences, Private Bag 3, WITS 2050, Johannesburg, South Africa.,IPHC, UNISTRA, CNRS, 23 rue du Loess, Strasbourg 67200, France
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33
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Barceló G, Love OP, Vézina F. Uncoupling Basal and Summit Metabolic Rates in White-Throated Sparrows: Digestive Demand Drives Maintenance Costs, but Changes in Muscle Mass Are Not Needed to Improve Thermogenic Capacity. Physiol Biochem Zool 2016; 90:153-165. [PMID: 28277963 DOI: 10.1086/689290] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Avian basal metabolic rate (BMR) and summit metabolic rate (Msum) vary in parallel during cold acclimation and acclimatization, which implies a functional link between these variables. However, evidence suggests that these parameters may reflect different physiological systems acting independently. We tested this hypothesis in white-throated sparrows (Zonotrichia albicollis) acclimated to two temperatures (-8° and 28°C) and two diets (0% and 30% cellulose). We expected to find an uncoupling of Msum and BMR where Msum, a measure of maximal shivering heat production, would reflect muscle and heart mass variation and would respond only to temperature, while BMR would reflect changes in digestive and excretory organs in response to daily food intake, responding to both temperature and diet. We found that the gizzard, liver, kidneys, and intestines responded to treatments through a positive relationship with food intake. BMR was 15% higher in cold-acclimated birds and, as expected, varied with food intake and the mass of digestive and excretory organs. In contrast, although Msum was 19% higher in cold-acclimated birds, only heart mass responded to temperature (+18% in the cold). Pectoral muscles did not change in mass with temperature but were 8.2% lighter on the cellulose diet. Nevertheless, Msum varied positively with the mass of heart and skeletal muscles but only in cold-acclimated birds. Our results therefore suggest that an upregulation of muscle metabolic intensity is required for cold acclimation. This study increases support for the hypothesis that BMR and Msum reflect different physiological systems responding in parallel to constraints associated with cold environments.
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34
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Swanson DL, King MO, Culver W, Zhang Y. Within-Winter Flexibility in Muscle Masses, Myostatin, and Cellular Aerobic Metabolic Intensity in Passerine Birds. Physiol Biochem Zool 2016; 90:210-222. [PMID: 28277951 DOI: 10.1086/688956] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Metabolic rates of passerine birds are flexible traits that vary both seasonally and among and within winters. Seasonal variation in summit metabolic rates (Msum = maximum thermoregulatory metabolism) in birds is consistently correlated with changes in pectoralis muscle and heart masses and sometimes with variation in cellular aerobic metabolic intensity, so these traits might also be associated with shorter-term, within-winter variation in metabolic rates. To determine whether these mechanisms are associated with within-winter variation in Msum, we examined the effects of short-term (ST; 0-7 d), medium-term (MT; 14-30 d), and long-term (LT; 30-yr means) temperature variables on pectoralis muscle and heart masses, pectoralis expression of the muscle-growth inhibitor myostatin and its metalloproteinase activators TLL-1 and TLL-2, and pectoralis and heart citrate synthase (CS; an indicator of cellular aerobic metabolic intensity) activities for two temperate-zone resident passerines, house sparrows (Passer domesticus) and dark-eyed juncos (Junco hyemalis). For both species, pectoralis mass residuals were positively correlated with ST temperature variables, suggesting that cold temperatures resulted in increased turnover of pectoralis muscle, but heart mass showed little within-winter variation for either species. Pectoralis mRNA and protein expression of myostatin and the TLLs were only weakly correlated with ST and MT temperature variables, which is largely consistent with trends in muscle masses for both species. Pectoralis and heart CS activities showed weak and variable trends with ST temperature variables in both species, suggesting only minor effects of temperature variation on cellular aerobic metabolic intensity. Thus, neither muscle or heart masses, regulation by the myostatin system, nor cellular aerobic metabolic intensity varied consistently with winter temperature, suggesting that other factors regulate within-winter metabolic variation in these birds.
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35
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Basal and maximal metabolic rates differ in their response to rapid temperature change among avian species. J Comp Physiol B 2016; 186:919-35. [DOI: 10.1007/s00360-016-1001-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/22/2016] [Accepted: 05/17/2016] [Indexed: 11/28/2022]
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36
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Zhang Y, Eyster K, Liu JS, Swanson DL. Cross-training in birds: cold and exercise training produce similar changes in maximal metabolic output, muscle masses and myostatin expression in house sparrows (Passer domesticus). ACTA ACUST UNITED AC 2015; 218:2190-200. [PMID: 25987736 DOI: 10.1242/jeb.121822] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/08/2015] [Indexed: 01/18/2023]
Abstract
Maximal metabolic outputs for exercise and thermogenesis in birds presumably influence fitness through effects on flight and shivering performance. Because both summit (Msum, maximum thermoregulatory metabolic rate) and maximum (MMR, maximum exercise metabolic rate) metabolic rates are functions of skeletal muscle activity, correlations between these measurements and their mechanistic underpinnings might occur. To examine whether such correlations occur, we measured the effects of experimental cold and exercise training protocols for 3 weeks on body (Mb) and muscle (Mpec) masses, basal metabolic rate (BMR), Msum, MMR, pectoralis mRNA and protein expression for myostatin, and mRNA expression of TLL-1 and TLL-2 (metalloproteinase activators of myostatin) in house sparrows (Passer domesticus). Both training protocols increased Msum, MMR, Mb and Mpec, but BMR increased with cold training and decreased with exercise training. No significant differences occurred for pectoralis myostatin mRNA expression, but cold and exercise increased the expression of TLL-1 and TLL-2. Pectoralis myostatin protein levels were generally reduced for both training groups. These data clearly demonstrate cross-training effects of cold and exercise in birds, and are consistent with a role for myostatin in increasing pectoralis muscle mass and driving organismal increases in metabolic capacities.
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Affiliation(s)
- Yufeng Zhang
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Kathleen Eyster
- Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57105, USA
| | - Jin-Song Liu
- School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China
| | - David L Swanson
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
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37
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Seasonal metabolic variation over two years in an Afrotropical passerine bird. J Therm Biol 2015; 52:58-66. [PMID: 26267499 DOI: 10.1016/j.jtherbio.2015.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 05/14/2015] [Accepted: 05/14/2015] [Indexed: 11/21/2022]
Abstract
Seasonal trends in metabolic parameters are well established in avian populations from highly seasonal environments, however, seasonal trends in metabolism of birds from lower latitudes (and of Afrotropical birds in particular) are not well understood. We investigated seasonal trends in metabolism for a small (10-12g) Afrotropical bird, the Cape White-eye (Zosterops virens), using flow-through respirometry in two summers and two winters. There was no seasonal difference in body mass between consecutive seasons. The lower critical limit of thermoneutrality was lower in winter (23°C) than in summer (28°C), as expected for a small Afrotropical bird. In the first year of the study, mean whole animal basal metabolic rate (BMR) of Cape White-eyes was significantly lower in winter than in summer, while in the second year of the study this trend was reversed, and in the middle two seasons there was no significant difference in BMR. Differences in mean temperature and mean rainfall between seasons could not account for the seasonal trends in BMR. We conclude that seasonal trends in avian BMR may vary between years, within a population.
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38
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Royer-Boutin P, Cortés PA, Milbergue M, Petit M, Vézina F. Estimation of Muscle Mass by Ultrasonography Differs between Observers and Life States of Models in Small Birds. Physiol Biochem Zool 2015; 88:336-44. [PMID: 25860831 DOI: 10.1086/680016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Pascal Royer-Boutin
- Département de Biologie, Chimie, et Géographie, Université du Québec à Rimouski, Rimouski, Québec G5L 3A1, Canada; 2Centre d'Études Nordiques, Québec, Québec G1V 0A6, Canada; 3Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, Valdivia 567, Chile; 4Centre de la Science de la Biodiversité du Québec, Montréal, Québec H3A 1B1, Canada
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Cortés PA, Petit M, Lewden A, Milbergue M, Vézina F. Individual inconsistencies in basal and summit metabolic rate highlight flexibility of metabolic performance in a wintering passerine. ACTA ACUST UNITED AC 2015; 323:179-90. [DOI: 10.1002/jez.1908] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 01/22/2023]
Affiliation(s)
- Pablo Andrés Cortés
- Instituto de Ciencias Ambientales y; Facultad de Ciencias; Universidad Austral de Chile Campus Isla Teja; Valdivia Chile
| | - Magali Petit
- Département de biologie; chimie et géographie; Université du Québec à Rimouski; Rimouski Canada
- Groupe de recherche sur les environnements nordiques BORÉAS; Rimouski Canada
- Centre d'Etudes Nordiques; Québec Canada
- Centre de la Science de la Biodiversité du Québec; Montréal Canada
| | - Agnès Lewden
- Département de biologie; chimie et géographie; Université du Québec à Rimouski; Rimouski Canada
- Groupe de recherche sur les environnements nordiques BORÉAS; Rimouski Canada
| | - Myriam Milbergue
- Département de biologie; chimie et géographie; Université du Québec à Rimouski; Rimouski Canada
- Groupe de recherche sur les environnements nordiques BORÉAS; Rimouski Canada
- Centre d'Etudes Nordiques; Québec Canada
- Centre de la Science de la Biodiversité du Québec; Montréal Canada
| | - François Vézina
- Département de biologie; chimie et géographie; Université du Québec à Rimouski; Rimouski Canada
- Groupe de recherche sur les environnements nordiques BORÉAS; Rimouski Canada
- Centre d'Etudes Nordiques; Québec Canada
- Centre de la Science de la Biodiversité du Québec; Montréal Canada
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40
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Petit M, Vézina F. Reaction norms in natural conditions: how does metabolic performance respond to weather variations in a small endotherm facing cold environments? PLoS One 2014; 9:e113617. [PMID: 25426860 PMCID: PMC4245212 DOI: 10.1371/journal.pone.0113617] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 10/29/2014] [Indexed: 11/30/2022] Open
Abstract
Reaction norms reflect an organisms' capacity to adjust its phenotype to the environment and allows for identifying trait values associated with physiological limits. However, reaction norms of physiological parameters are mostly unknown for endotherms living in natural conditions. Black-capped chickadees (Poecile atricapillus) increase their metabolic performance during winter acclimatization and are thus good model to measure reaction norms in the wild. We repeatedly measured basal (BMR) and summit (Msum) metabolism in chickadees to characterize, for the first time in a free-living endotherm, reaction norms of these parameters across the natural range of weather variation. BMR varied between individuals and was weakly and negatively related to minimal temperature. Msum varied with minimal temperature following a Z-shape curve, increasing linearly between 24°C and −10°C, and changed with absolute humidity following a U-shape relationship. These results suggest that thermal exchanges with the environment have minimal effects on maintenance costs, which may be individual-dependent, while thermogenic capacity is responding to body heat loss. Our results suggest also that BMR and Msum respond to different and likely independent constraints.
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Affiliation(s)
- Magali Petit
- Département de Biologie, chimie et géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski (Québec), G5L 3A1, Canada
- Groupe de recherche sur les environnements nordiques BOREAS, Rimouski (Québec), Canada
- Centre d'Etudes Nordiques, Québec (Québec), Canada
- Centre de la Science de la Biodiversité du Québec, Montréal (Québec), Canada
- * E-mail:
| | - François Vézina
- Département de Biologie, chimie et géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski (Québec), G5L 3A1, Canada
- Groupe de recherche sur les environnements nordiques BOREAS, Rimouski (Québec), Canada
- Centre d'Etudes Nordiques, Québec (Québec), Canada
- Centre de la Science de la Biodiversité du Québec, Montréal (Québec), Canada
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41
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Devost I, Hallot F, Milbergue M, Petit M, Vézina F. Lipid metabolites as markers of fattening rate in a non-migratory passerine: Effects of ambient temperature and individual variation. Comp Biochem Physiol A Mol Integr Physiol 2014; 177:18-26. [DOI: 10.1016/j.cbpa.2014.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 10/25/2022]
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42
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Swanson D, Zhang Y, King M. Mechanistic drivers of flexibility in summit metabolic rates of small birds. PLoS One 2014; 9:e101577. [PMID: 24992186 PMCID: PMC4081579 DOI: 10.1371/journal.pone.0101577] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/08/2014] [Indexed: 11/19/2022] Open
Abstract
Flexible metabolic phenotypes allow animals to adjust physiology to better fit ecological or environmental demands, thereby influencing fitness. Summit metabolic rate (Msum = maximal thermogenic capacity) is one such flexible trait. Skeletal muscle and heart masses and myocyte metabolic intensity are potential drivers of Msum flexibility in birds. We examined correlations of skeletal muscle and heart masses and pectoralis muscle citrate synthase (CS) activity (an indicator of cellular metabolic intensity) with Msum in house sparrows (Passer domesticus) and dark-eyed juncos (Junco hyemalis) to determine whether these traits are associated with Msum variation. Pectoralis mass was positively correlated with Msum for both species, but no significant correlation remained for either species after accounting for body mass (Mb) variation. Combined flight and leg muscle masses were also not significantly correlated with Msum for either species. In contrast, heart mass was significantly positively correlated with Msum for juncos and nearly so (P = 0.054) for sparrows. Mass-specific and total pectoralis CS activities were significantly positively correlated with Msum for sparrows, but not for juncos. Thus, myocyte metabolic intensity influences Msum variation in house sparrows, although the stronger correlation of total (r = 0.495) than mass-specific (r = 0.378) CS activity with Msum suggests that both pectoralis mass and metabolic intensity impact Msum. In contrast, neither skeletal muscle masses nor pectoralis metabolic intensity varied with Msum in juncos. However, heart mass was associated with Msum variation in both species. These data suggest that drivers of metabolic flexibility are not uniform among bird species.
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Affiliation(s)
- David Swanson
- Department of Biology, University of South Dakota, Vermillion, South Dakota, United States of America
- * E-mail:
| | - Yufeng Zhang
- Department of Biology, University of South Dakota, Vermillion, South Dakota, United States of America
| | - Marisa King
- Department of Biology, University of South Dakota, Vermillion, South Dakota, United States of America
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43
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Petit M, Lewden A, Vézina F. How does flexibility in body composition relate to seasonal changes in metabolic performance in a small passerine wintering at northern latitude? Physiol Biochem Zool 2014; 87:539-49. [PMID: 24940918 DOI: 10.1086/676669] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Abstract Small avian species wintering at northern latitudes typically show increases in basal metabolic rate (BMR) and maximal thermogenic capacity (Msum). Those are widely assumed to reflect changes in body composition, with enlargement of digestive and excretory organs resulting in elevated winter BMR and larger body muscles driving the increase in Msum. Using free-living black-capped chickadees (Poecile atricapillus) as our model species, we investigated seasonal changes in body composition and tested for relationships between mass variations of body organs and variability of both BMR and Msum. Our results confirmed the expected winter increase in mass of body muscles and cardiopulmonary organs (heart + lungs) and showed that 64% of the observed Msum variations throughout the year were explained by changes in these organs. In contrast, we found little support for an effect of the digestive organs (gizzard + intestines) on BMR seasonal changes. Instead, this variable was mainly influenced by variations in mass of body muscles and excretory organs (liver + kidney), explaining up to 35% of its variability.
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Affiliation(s)
- Magali Petit
- Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada; 2Centre de la Science de la Biodiversité du Québec, Montréal, Québec H3A 1B1, Canada
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Swanson D, Zhang Y, Liu JS, Merkord CL, King MO. Relative roles of temperature and photoperiod as drivers of metabolic flexibility in dark-eyed juncos. J Exp Biol 2014; 217:866-75. [DOI: 10.1242/jeb.096677] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Seasonal phenotypic flexibility in small birds produces a winter phenotype with elevated maximum cold-induced metabolic rates (=summit metabolism, Ṁsum). Temperature and photoperiod are candidates for drivers of seasonal phenotypes, but their relative impacts on metabolic variation are unknown. We examined photoperiod and temperature effects on Ṁsum, muscle masses and activities of key catabolic enzymes in winter dark-eyed juncos (Junco hyemalis). We randomly assigned birds to four treatment groups varying in temperature (cold=3°C; warm=24°C) and photoperiod [short day (SD)=8 h:16 h light:dark; long day (LD)=16 h:8 h light:dark] in a two-by-two design. We measured body mass (Mb), flight muscle width and Ṁsum before and after 3 and 6 weeks of acclimation, and flight muscle and heart masses after 6 weeks. Ṁsum increased for cold-exposed, but not for warm-exposed, birds. LD birds gained more Mb than SD birds, irrespective of temperature. Flight muscle size and mass did not differ significantly among groups, but heart mass was larger in cold-exposed birds. Citrate synthase, carnitine palmitoyl transferase and β-hydroxyacyl Co-A dehydrogenase activities in the pectoralis were generally higher for LD and cold groups. The cold-induced changes in Ṁsum and heart mass parallel winter changes for small birds, but the larger Mb and higher catabolic enzyme activities in LD birds suggest photoperiod-induced changes associated with migratory disposition. Temperature appears to be a primary driver of flexibility in Ṁsum in juncos, but photoperiod-induced changes in Mb and catabolic enzyme activities, likely associated with migratory disposition, interact with temperature to contribute to seasonal phenotypes.
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Affiliation(s)
- David Swanson
- Department of Biology, University of South Dakota, 414 E Clark St., Vermillion, SD 57069, USA
| | - Yufeng Zhang
- Department of Biology, University of South Dakota, 414 E Clark St., Vermillion, SD 57069, USA
| | - Jin-Song Liu
- School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China
| | - Christopher L. Merkord
- Department of Biology, University of South Dakota, 414 E Clark St., Vermillion, SD 57069, USA
| | - Marisa O. King
- Department of Biology, University of South Dakota, 414 E Clark St., Vermillion, SD 57069, USA
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Swanson DL, King MO, Harmon E. Seasonal variation in pectoralis muscle and heart myostatin and tolloid-like proteinases in small birds: a regulatory role for seasonal phenotypic flexibility? J Comp Physiol B 2014; 184:249-58. [PMID: 24395519 DOI: 10.1007/s00360-013-0798-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 12/16/2013] [Accepted: 12/20/2013] [Indexed: 01/08/2023]
Abstract
Seasonally variable environments produce seasonal phenotypes in small birds such that winter birds have higher thermogenic capacities and pectoralis and heart masses. One potential regulator of these seasonal phenotypes is myostatin, a muscle growth inhibitor, which may be downregulated under conditions promoting increased energy demand. We examined summer-to-winter variation in skeletal muscle and heart masses and used qPCR and Western blots to measure levels of myostatin and its metalloproteinase activators TLL-1 and TLL-2 for two small temperate-zone resident birds, American goldfinches (Spinus tristis) and black-capped chickadees (Poecile atricapillus). Winter pectoralis and heart masses were significantly greater than in summer for American goldfinches. Neither myostatin expression nor protein levels differed significantly between seasons for goldfinch pectoralis. However, myostatin levels in goldfinch heart were significantly greater in summer than in winter, although heart myostatin expression was seasonally stable. In addition, expression of both metalloproteinase activators was greater in summer than in winter goldfinches for both pectoralis and heart, significantly so except for heart TLL-2 (P = 0.083). Black-capped chickadees showed no significant seasonal variation in muscle or heart masses. Seasonal patterns of pectoralis and heart expression and/or protein levels for myostatin and its metalloproteinase activators in chickadees showed no consistent seasonal trends, which may help explain the absence of significant seasonal variation in muscle or heart masses for chickadees in this study. These data are partially consistent with a regulatory role for myostatin, and especially myostatin processing capacity, in mediating seasonal metabolic phenotypes of small birds.
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Affiliation(s)
- David L Swanson
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA,
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Petit M, Vézina F. Phenotype manipulations confirm the role of pectoral muscles and haematocrit in avian maximal thermogenic capacity. J Exp Biol 2013; 217:824-30. [DOI: 10.1242/jeb.095703] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
In small resident bird species living at northern latitudes, winter cold acclimatization is associated with an increase in pectoral muscle size and haematocrit level and this is thought to drive the seasonal increase in summit metabolic rate (Msum, a measure of maximal shivering thermogenic capacity). However, evidences suggesting that pectoral muscle size influences Msum are correlational and the link between haematrocrit level and Msum remains to be demonstrated. We experimentally tested the relationship between pectoral muscle size and Msum by manipulating muscle size using a feather clipping protocol in free-living wintering black-capped chickadees (Poecile atricapillus). This also allowed us to investigate the link between haematocrit and thermogenic capacity. After a first series of measures on all birds, we cut half of the flight feathers of experimental individuals (n = 14) and compared their fat and pectoral muscle scores, Msum and haematocrit level at recapture with their previous measures and with those of control birds (n = 17) that were captured and recaptured at comparable times. Results showed 1) that experimental birds developed larger pectoral muscles than control individuals and 2) that mass-independent Msum was up to 16% higher in birds expressing large pectoral muscles. Msum was also positively correlated with haematocrit, which was not affected by the experimental manipulation. These findings demonstrate that, for a given body mass, large pectoral muscles are associated with a higher Msum in black-capped chickadees and that oxygen carrying capacity likely supports thermogenesis in this species.
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