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Millanes PM, Pérez-Rodríguez L, Rubalcaba JG, Gil D, Jimeno B. Corticosterone and glucose are correlated and show similar response patterns to temperature and stress in a free-living bird. J Exp Biol 2024; 227:jeb246905. [PMID: 38949462 DOI: 10.1242/jeb.246905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 06/24/2024] [Indexed: 07/02/2024]
Abstract
Glucocorticoid (GC) hormones have traditionally been interpreted as indicators of stress, but the extent to which they provide information on physiological state remains debated. GCs are metabolic hormones that amongst other functions ensure increasing fuel (i.e. glucose) supply on the face of fluctuating energetic demands, a role often overlooked by ecological studies investigating the consequences of GC variation. Furthermore, because energy budget is limited, in natural contexts where multiple stimuli coexist, the organisms' ability to respond physiologically may be constrained when multiple triggers of metabolic responses overlap in time. Using free-living spotless starling (Sturnus unicolor) chicks, we experimentally tested whether two stimuli of different nature known to trigger a metabolic or GC response, respectively, cause a comparable increase in plasma GCs and glucose. We further tested whether response patterns differed when both stimuli occurred consecutively. We found that both experimental treatments caused increases in GCs and glucose of similar magnitude, suggesting that both variables fluctuate along with variation in energy expenditure, independently of the trigger. Exposure to the two stimuli occurring subsequently did not cause a difference in GC or glucose responses compared with exposure to a single stimulus, suggesting a limited capacity to respond to an additional stimulus during an ongoing acute response. Lastly, we found a positive and significant correlation between plasma GCs and glucose after the experimental treatments. Our results add to the increasing research on the role of energy expenditure on GC variation, by providing experimental evidence on the association between plasma GCs and energy metabolism.
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Affiliation(s)
- Paola M Millanes
- Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, 28933 Móstoles, Madrid, Spain
| | - Lorenzo Pérez-Rodríguez
- Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ronda de Toledo 12, 13005 Ciudad Real, Spain
| | - Juan G Rubalcaba
- Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, 28933 Móstoles, Madrid, Spain
- Department of Biodiversity, Ecology and Evolution, Faculty of Biological Sciences. Complutense University of Madrid, José Antonio Novais, 12, 28040 Madrid, Spain
| | - Diego Gil
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal, 2, 28006 Madrid, Spain
| | - Blanca Jimeno
- Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ronda de Toledo 12, 13005 Ciudad Real, Spain
- Pyrenean Institute of Ecology (IPE-CSIC), Avda Nuestra Señora de la Victoria, s/n, 22700 Jaca, Huesca, Spain
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2
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Newediuk L, Bath DR. Meta-analysis reveals between-population differences affect the link between glucocorticoids and population health. CONSERVATION PHYSIOLOGY 2023; 11:coad005. [PMID: 36845329 PMCID: PMC9945071 DOI: 10.1093/conphys/coad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Glucocorticoids are a popular tool for monitoring health of animal populations because they can increase with environmental stressors and can indicate chronic stress. However, individual responses to stressors create variation in the glucocorticoid-fitness relationship within populations. The inconsistency in this relationship calls into question the widespread use of glucocorticoids in conservation. We investigated the sources of variation in the glucocorticoid-fitness relationship by conducting a meta-analysis across a diverse set of species exposed to conservation-relevant stressors. We first quantified the extent to which studies inferred population health from glucocorticoids without first validating the glucocorticoid-fitness relationship in their own populations. We also tested whether population-level information like life history stage, sex and species longevity influenced the relationship between glucocorticoids and fitness. Finally, we tested for a universally consistent relationship between glucocorticoids and fitness across studies. We found more than half of peer-reviewed studies published between 2008 and 2022 inferred population health solely based on glucocorticoid levels. While life history stage explained some variation in the relationship between glucocorticoids and fitness, we found no consistent relationship between them. Much of the variation in the relationship could be the result of idiosyncratic characteristics of declining populations, such as unstable demographic structure, that coincided with large amounts of variation in glucocorticoid production. We suggest that conservation biologists capitalize on this variation in glucocorticoid production by declining populations by using the variance in glucocorticoid production as an early warning for declines in population health.
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Affiliation(s)
- Levi Newediuk
- Corresponding author: Department of Biology, Memorial University, 45 Arctic Avenue, St. John's, Newfoundland A1B 3X9, Canada.
| | - Devon R Bath
- Department of Ocean Sciences, Memorial University, 0 Marine Lab Road, St. John's, Newfoundland A1C 5S7, Canada
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Behnke T, Street P, Davies S, Ouyang JQ, Sedinger JS. Non-native grazers affect physiological and demographic responses of greater sage-grouse. Ecol Evol 2022; 12:e9325. [PMID: 36188508 PMCID: PMC9490135 DOI: 10.1002/ece3.9325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/01/2022] [Accepted: 08/28/2022] [Indexed: 11/12/2022] Open
Abstract
Non-native ungulate grazing has negatively impacted native species across the globe, leading to massive loss of biodiversity and ecosystem services. Despite their pervasiveness, interactions between non-native grazers and native species are not fully understood. We often observe declines in demography or survival of these native species, but lack understanding about the mechanisms underlying these declines. Physiological stress represents one mechanism of (mal)adaptation, but data are sparse. We investigated glucocorticoid levels in a native avian herbivore exposed to different intensities of non-native grazing in the cold desert Great Basin ecosystem, USA. We measured corticosterone, a glucocorticoid in feathers for a large sample (n = 280) of female greater sage-grouse (Centrocercus urophasianus) from three study areas in Northern Nevada and Southern Oregon with different grazing regimes of livestock and feral horses. We found that greater feral horse density was associated with higher corticosterone levels, and this effect was exacerbated by drought conditions. Livestock grazing produced similar results; however, there was more model uncertainty about the livestock effect. Subsequent nesting success was lower with increased feather corticosterone, but corticosterone levels were not predictive of other vital rates. Our results indicate a physiological response by sage-grouse to grazing pressure from non-native grazers. We found substantial among-individual variation in the strength of the response. These adverse effects were intensified during unfavorable weather events, highlighting the need to reevaluate management strategies in the face of climate change.
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Affiliation(s)
- Tessa Behnke
- Program in Ecology, Evolution, and Conservation BiologyUniversity of Nevada–RenoRenoNevadaUSA
- Department of Natural Resources and Environmental ScienceUniversity of Nevada–RenoRenoNevadaUSA
| | - Phillip Street
- Department of Natural Resources and Environmental ScienceUniversity of Nevada–RenoRenoNevadaUSA
| | - Scott Davies
- Department of Biological SciencesQuinnipiac UniversityHamdenConnecticutUSA
| | - Jenny Q. Ouyang
- Program in Ecology, Evolution, and Conservation BiologyUniversity of Nevada–RenoRenoNevadaUSA
| | - James S. Sedinger
- Department of Natural Resources and Environmental ScienceUniversity of Nevada–RenoRenoNevadaUSA
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4
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Fischer D, Marrotte RR, Chin EH, Coulson S, Burness G. Maternal glucocorticoid levels during incubation predict breeding success, but not reproductive investment, in a free-ranging bird. Biol Open 2020; 9:9/10/bio045898. [PMID: 33077551 PMCID: PMC7595688 DOI: 10.1242/bio.045898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hormone corticosterone (CORT) has been hypothesized to be linked with fitness, but the directionality of the relationship is unclear. The ‘CORT-fitness hypothesis’ proposes that high levels of CORT arise from challenging environmental conditions, resulting in lower reproductive success (a negative relationship). In contrast, the CORT-adaptation hypothesis suggests that, during energetically demanding periods, CORT will mediate physiological or behavioral changes that result in increased reproductive investment and success (a positive relationship). During two breeding seasons, we experimentally manipulated circulating CORT levels in female tree swallows (Tachycineta bicolor) prior to egg laying, and measured subsequent reproductive effort, breeding success, and maternal survival. When females were recaptured during egg incubation and again during the nestling stage, the CORT levels were similar among individuals in each treatment group, and maternal treatment had no effect on indices of fitness. By considering variation among females, we found support for the CORT-adaptation hypothesis; there was a significant positive relationship between CORT levels during incubation and hatching and fledging success. During the nestling stage CORT levels were unrelated to any measure of investment or success. Within the environmental context of our study, relationships between maternal glucocorticoid levels and indices of fitness vary across reproductive stages. Summary: Levels of the stress biomarker corticosterone predict breeding success in female tree swallows. However, correlations between hormone levels and fitness differ between life-history stages.
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Affiliation(s)
- Devin Fischer
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada K9L 0G2
| | - Robby R Marrotte
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada K9L 0G2
| | - Eunice H Chin
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Smolly Coulson
- Department of Biology, Trent University, Peterborough, Ontario, Canada K9L 0G2
| | - Gary Burness
- Department of Biology, Trent University, Peterborough, Ontario, Canada K9L 0G2
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Pritchard CE, Palme R, Langkilde T. Glucocorticoid and triiodothyronine concentrations do not correlate with behavior in vicuñas (Vicugna vicugna). Gen Comp Endocrinol 2020; 286:113299. [PMID: 31606464 DOI: 10.1016/j.ygcen.2019.113299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 10/07/2019] [Accepted: 10/09/2019] [Indexed: 11/26/2022]
Abstract
State-dependent foraging theory posits that animals should make foraging decisions based on energetic condition, where animals with fewer energetic reserves prioritize foraging over other behaviors, including antipredator behaviors. However, few studies have investigated these trade-offs at an individual level in wild, free-ranging animals. We investigated the relationships between internal condition and behavior in a wild mammal, the vicuña (Vicugna vicugna), which makes state-dependent decisions about the use of two habitats with different characteristics that contribute to their internal condition. Using non-invasively collected fecal samples, we measured glucocorticoid metabolites (GCMs) and thyroid hormones (THs) as indicators of combined stress (predation and nutritional), and just nutritional stress, respectively. We video recorded 20-minute behavioral observations and focused on behaviors which often demand a trade-off between energy acquisition and antipredator behaviors-vigilance and foraging. We found differences in expression of these behaviors between the two sites but found no relationships between physiological parameters (GCMs and THs) and behavior (vigilance and foraging) at either site. We suggest that state-dependent foraging may be difficult to observe in large mammals under baseline conditions and that GCMs and THs may be insensitive to small changes in stress stimuli at this scale, and where these wild animals have the entire suite of behavioral responses available to them.
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Affiliation(s)
- Catharine E Pritchard
- 208 Mueller Laboratory, The Pennsylvania State University, University Park, PA 16801, USA.
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Tracy Langkilde
- 208 Mueller Laboratory, The Pennsylvania State University, University Park, PA 16801, USA.
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Lehman CP, Rota CT, Millspaugh JJ. Nutritional condition and physiological stress levels of elk in the Black Hills, South Dakota. PeerJ 2019; 7:e7185. [PMID: 31293830 PMCID: PMC6599675 DOI: 10.7717/peerj.7185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/19/2019] [Indexed: 11/20/2022] Open
Abstract
Percent of body fat and physiological stress are important correlates to wildlife demographics. We studied winter percent of body fat and physiological stress levels for a declining elk (Cervus canadensis nelsoni) population in South Dakota, 2011–2013. We obtained percent of winter body fat, pregnancy status, lactation status, and physiological stress data from 58 adult females (2+ years old). We compared physiological stress level data from 2011 with data collected from this same herd when elk densities were much higher (1995–1997). Our objectives were to determine percent of body fat during winter, examine if winter body fat was correlated with pregnancy and lactation status, and quantify and compare physiological stress hormone values from elk in the mid-1990s. Probability of being pregnant increased with higher winter nutritional condition, or percent of body fat; whereas females with a higher probability of previously lactating were lower in winter body fat. Mean fecal glucocorticoid metabolite (FGM) levels in 2011 (mean = 47.78 ng/g, SE = 2.37) were higher during summer compared to data collected in 1995–1997 (mean = 34.21 ng/g, SE = 3.71); however, mean FGM levels during winter did not differ between the two time periods. Although summer levels of FGM have significantly increased since the mid-1990s, we caution against any interpretation of increased FGM levels on elk fitness, as it may not infer biological significance. Mean winter percent of body fat of elk was lower when compared to other populations in the west but this difference does not appear to be limiting vital rates and population growth for this elk herd. We recommend future research focus on summer/autumn data collection to provide a more comprehensive understanding of percent of body fat for elk in our region.
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Affiliation(s)
| | - Christopher T Rota
- School of Natural Resources, Wildlife and Fisheries Resource Program, West Virginia University, Morgantown, WV, USA
| | - Joshua J Millspaugh
- Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, USA
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Griebel IA, Fairhurst GD, Marchant TA, Clark RG. Effects of parental and nest-site characteristics on nestling quality in the Tree Swallow (Tachycineta bicolor). CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0109] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Natal environment and parental quality can influence offspring phenotype, including physiological and morphological traits. We investigated how offspring morphology and feather corticosterone (CORTf; a physiological index of allostatic load) may be related to nest environment and parental characteristics by cross-fostering 3-day-old nestling Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) between quaking aspen (Populus tremuloides Michx.) and plywood nest boxes that differed in microclimate. We evaluated the relative importance of natal influences, common rearing environment, and nest-box environment on nestling quality. Nestlings raised in quaking aspen boxes tended to have lower CORTf, although this result only approached significance. Nestling body mass was best predicted by the biological mother’s mass and random effects of natal and rearing nest identity, wing length was best predicted by random effects of rearing nest, and head–bill length was best predicted by random effects of natal nest. Therefore, nest microclimate was more important than maternal characteristics in predicting nestling physiology (CORTf), while nestling morphology was influenced by maternal morphology, as well as natal and rearing nest environments. Our study provides important information about how environmental and parental influences affect nestling phenotype and will help future studies interpret similar morphological and physiological indices of nestling quality.
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Affiliation(s)
- Ilsa A. Griebel
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada
| | - Graham D. Fairhurst
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada
| | - Tracy A. Marchant
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada
| | - Robert G. Clark
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada
- Environment and Climate Change Canada, 116 Veterinary Road, Saskatoon, SK S7N 0X4, Canada
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Hammond TT, Palme R, Lacey EA. Glucocorticoid-environment relationships align with responses to environmental change in two co-occurring congeners. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1683-1693. [PMID: 30043471 DOI: 10.1002/eap.1781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/08/2018] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
As more species undergo range shifts in response to climate change, it is increasingly important to understand the factors that determine an organism's realized niche. Physiological limits imposed by abiotic factors constrain the distributions of many species. Because glucocorticoids are essential to the maintenance of physiological homeostasis, identifying glucocorticoid-environment relationships may generate critical insights into both limits on species distributions and potential responses to environmental change. We explored relationships between variability in baseline glucocorticoids and sensitivity to environmental conditions in two chipmunk species characterized by divergent patterns of spatial, genetic, and morphological change over the past century. Specifically, we investigated whether the alpine chipmunk (Tamias alpinus), which has undergone pronounced changes, displays greater glucocorticoid sensitivity to environmental parameters than the lodgepole chipmunk (T. speciosus), which has exhibited little change over the same interval. From 2013 to 2015, we collected environmental data and fecal glucocorticoid metabolite (FGM) samples from these species. Using generalized linear mixed models and a model averaging approach, we examined the impacts of environmental and individual phenotypic parameters on FGMs. We found pronounced interspecific differences, with environmental parameters being better predictors of FGMs in T. alpinus. FGMs in this species were particularly elevated in less climatically suitable habitats and in areas with higher maximum daily temperatures. Individual phenotypic traits were not predictive of FGMs in T. alpinus, although they were highly predictive for T. speciosus. Collectively, these findings support the hypothesis that T. alpinus is more sensitive to environmental change. More generally, our results suggest that both phenotypic attributes and environmental conditions contribute to FGM responses but that the relative contributions of these factors differ among taxa, including among closely related species. Finally, our analyses underscore the value of glucocorticoids as bioindicators of sensitivity to environmental change in species for which the factors affecting stress physiology have been assessed.
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Affiliation(s)
- Talisin T Hammond
- Department of Biological Sciences, University of Pittsburgh, 105 Clapp Hall, Pittsburgh, Pennsylvania, 15260, USA
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, California, 94720-3160, USA
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Eileen A Lacey
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, California, 94720-3160, USA
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Neuman‐Lee LA, Terletzky PA, Atwood TC, Gese EM, Smith GD, Greenfield S, Pettit J, French SS. Demographic and temporal variations in immunity and condition of polar bears (
Ursus maritimus
) from the southern Beaufort Sea. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2017; 327:333-346. [DOI: 10.1002/jez.2112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/27/2017] [Accepted: 08/29/2017] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Todd C. Atwood
- U.S. Geological Survey Alaska Science Center Anchorage Alaska
| | - Eric M. Gese
- Department of Wildland Resources Utah State University Logan Utah
- U.S. Department of Agriculture Wildlife Services National Wildlife Research Center Logan Utah
| | - Geoffrey D. Smith
- Department of Biological Sciences Dixie State University St. George Utah
| | | | - John Pettit
- Department of Biology Utah State University Logan Utah
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