1
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Ruthsatz K, Rico-Millan R, Eterovick PC, Gomez-Mestre I. Exploring water-borne corticosterone collection as a non-invasive tool in amphibian conservation physiology: benefits, limitations and future perspectives. CONSERVATION PHYSIOLOGY 2023; 11:coad070. [PMID: 37663928 PMCID: PMC10472495 DOI: 10.1093/conphys/coad070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 08/03/2023] [Accepted: 08/26/2023] [Indexed: 09/05/2023]
Abstract
Global change exposes wildlife to a variety of environmental stressors and is affecting biodiversity worldwide, with amphibian population declines being at the forefront of the global biodiversity crisis. The use of non-invasive methods to determine the physiological state in response to environmental stressors is therefore an important advance in the field of conservation physiology. The glucocorticoid hormone corticosterone (CORT) is one useful biomarker to assess physiological stress in amphibians, and sampling water-borne (WB) CORT is a novel, non-invasive collection technique. Here, we tested whether WB CORT can serve as a valid proxy of organismal levels of CORT in larvae of the common frog (Rana temporaria). We evaluated the association between tissue and WB CORT levels sampled from the same individuals across ontogenetic stages, ranging from newly hatched larvae to froglets at 10 days after metamorphosis. We also investigated how both tissue and WB CORT change throughout ontogeny. We found that WB CORT is a valid method in pro-metamorphic larvae as values for both methods were highly correlated. In contrast, there was no correlation between tissue and WB CORT in newly hatched, pre-metamorphic larvae, metamorphs or post-metamorphic froglets probably due to ontogenetic changes in respiratory and skin morphology and physiology affecting the transdermal CORT release. Both collection methods consistently revealed a non-linear pattern of ontogenetic change in CORT with a peak at metamorphic climax. Thus, our results indicate that WB CORT sampling is a promising, non-invasive conservation tool for studies on late-stage amphibian larvae. However, we suggest considering that different contexts might affect the reliability of WB CORT and consequently urge future studies to validate this method whenever it is used in new approaches. We conclude proposing some recommendations and perspectives on the use of WB CORT that will aid in broadening its application as a non-invasive tool in amphibian conservation physiology.
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Affiliation(s)
- Katharina Ruthsatz
- Zoological Institute, Technische Universität Braunschweig, Mendelssohnstraße 4, 38106 Braunschweig, Germany
| | - Rafael Rico-Millan
- Ecology, Evolution, and Development Group, Doñana Biological Station – CSIC, Calle Américo Vespucio 26, 41092 Seville, Spain
| | - Paula Cabral Eterovick
- Zoological Institute, Technische Universität Braunschweig, Mendelssohnstraße 4, 38106 Braunschweig, Germany
| | - Ivan Gomez-Mestre
- Ecology, Evolution, and Development Group, Doñana Biological Station – CSIC, Calle Américo Vespucio 26, 41092 Seville, Spain
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2
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Ton R, Boner W, Raveh S, Monaghan P, Griffith SC. Effects of heat waves on telomere dynamics and parental brooding effort in nestlings of the zebra finch (Taeniopygia castanotis) transitioning from ectothermy to endothermy. Mol Ecol 2023; 32:4911-4920. [PMID: 37395529 DOI: 10.1111/mec.17064] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/04/2023]
Abstract
Heat waves are predicted to be detrimental for organismal physiology with costs for survival that could be reflected in markers of biological state such as telomeres. Changes in early life telomere dynamics driven by thermal stress are of particular interest during the early post-natal stages of altricial birds because nestlings quickly shift from being ectothermic to endothermic after hatching. Telomeres of ectothermic and endothermic organisms respond differently to environmental temperature, but few investigations within species that transition from ectothermy to endothermy are available. Also, ambient temperature influences parental brooding behaviour, which will alter the temperature experienced by offspring and thereby, potentially, their telomeres. We exposed zebra finch nestlings to experimental heat waves and compared their telomere dynamics to that of a control group at 5, 12 and 80 days of age that encapsulate the transition from the ectothermic to the endothermic thermoregulatory stage; we also recorded parental brooding, offspring sex, mass, growth rates, brood size and hatch order. Nestling mass showed an inverse relationship with telomere length, and nestlings exposed to heat waves showed lower telomere attrition during their first 12 days of life (ectothermic stage) compared to controls. Additionally, parents of heated broods reduced the time they spent brooding offspring (at 5 days old) compared to controls. Our results indicate that the effect of heat waves on telomere dynamics likely varies depending on age and thermoregulatory stage of the offspring in combination with parental brooding behaviour during growth.
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Affiliation(s)
- Riccardo Ton
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Winnie Boner
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Shirley Raveh
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Pat Monaghan
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Simon C Griffith
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
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3
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Hartzheim AM, Terry JL, Field EK, Haydt NT, Poo S, Neuman-Lee LA. Immune and stress physiology of two captively-housed tortoise species. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:220-233. [PMID: 36450699 DOI: 10.1002/jez.2674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/31/2022] [Accepted: 11/03/2022] [Indexed: 12/04/2022]
Abstract
Ecoimmunology affords us the ability to better understand immunological processes through consideration of external factors, such as the thermal microenvironment. This consideration is imperative when examining the immunological processes of ectothermic organisms like reptiles. Reptiles uniquely rely heavily on their innate immune function but remain poorly understood in immunological studies. In this study, we examined innate immunity in two zoo-housed tortoise species, the Indian star tortoise (Geochelone elegans, Schoepff, 1795) and northern spider tortoise (Pyxis arachnoides brygooi, Vuillemin & Domergue, 1972). Bacterial killing assays (BKAs) were optimized and used to assess the monthly immunocompetence of these tortoises to three different bacteria: Escherichia coli, Salmonella enterica, and Staphylococcus aureus. We evaluated differences in blood biochemistry values (lactate and glucose) among months and species as well as fecal corticosterone (CORT) between species. Lastly, we examined the potential influences of individual thermal microenvironments on bactericidal ability. Both G. elegans and P. a. brygooi demonstrated immunocompetence against all bacterial challenges, but only bactericidal ability against E. coli varied over months. Optimal BKA serum dilutions, blood glucose levels, and fecal CORT concentrations differed between the two species. Finally, there was evidence that the thermal microenvironment influenced the tortoises' bactericidal ability against E. coli. Through use of nonmodel organisms, such as tortoises, we are given insight into the inner workings of innate immunity and a better understanding of the complexities of the vertebrate immune system.
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Affiliation(s)
- Alyssa M Hartzheim
- Department of Biological Sciences, Arkansas State University, Jonesboro, Arkansas, USA
| | - Jennifer L Terry
- Department of Biological Sciences, Arkansas State University, Jonesboro, Arkansas, USA
| | - Emily K Field
- Department of Biological Sciences, Arkansas State University, Jonesboro, Arkansas, USA
| | - Natalie T Haydt
- Department of Biological Sciences, Arkansas State University, Jonesboro, Arkansas, USA
| | - Sinlan Poo
- Department of Conservation and Research, Memphis Zoological Society, Memphis, Tennessee, USA
| | - Lorin A Neuman-Lee
- Department of Biological Sciences, Arkansas State University, Jonesboro, Arkansas, USA
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4
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Trait Covariances in Eastern Box Turtles Do Not Support Pleiotropic Effects of the Melanocortin System on Color, Behavior, and Stress Physiology. J HERPETOL 2022. [DOI: 10.1670/22-010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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5
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Rubalcaba JG, Jimeno B. Body temperature and activity patterns modulate glucocorticoid levels across lizard species: A macrophysiological approach. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1032083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Environmental and intrinsic factors interact to determine energy requirements in vertebrates. Glucocorticoid hormones (GCs) are key mediators of this interaction, as they fluctuate with energetic demands and regulate physiological and behavioral responses to environmental challenges. While a great body of research has focused on GC variation among individuals, the mechanisms driving GC variation across species and at broad spatial scales remain largely unexplored. Here, we adopted a macrophysiological approach to investigate the environmental factors and life-history traits driving variation in baseline GCs across lizard species. We tested three hypotheses: (1) If GCs increase with body temperature to meet higher metabolic demand, we expect an association between average baseline GCs and the mean species’ body temperature in the field (GC-temperature dependence hypothesis); (2) If GCs mediate behavioral responses to avoid thermal extremes, we expect that individuals frequently exposed to extreme conditions exhibit higher baseline GC levels (Behavioral thermoregulation hypothesis); (3) If GCs increase to support higher energy demands in active foragers during their period of activity, we expect that active foraging species have higher baseline GCs than sit-and-wait foragers, and that GC levels increase in relation to the duration of daily activity windows (Activity hypothesis). We used biophysical models to calculate operative temperatures and the activity patterns of lizards in sun-exposed and shaded microenvironments. Then, we tested the association between baseline GCs, body temperature, operative temperatures, foraging mode, and activity windows across 37 lizard species, using data from HormoneBase. Our comparative analyses showed that variation in baseline GCs was primarily related to the mean field body temperature and foraging mode, with higher baseline GCs in active foragers with higher body temperatures. Our results suggest that body temperature and foraging mode drive GC variation through their effects on energy requirements across lizard species.
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6
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Chang J, Pan Y, Liu W, Xie Y, Hao W, Xu P, Wang Y. Acute temperature adaptation mechanisms in the native reptile species Eremias argus. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 818:151773. [PMID: 34808164 DOI: 10.1016/j.scitotenv.2021.151773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/13/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Reptiles are sensitive to temperature changes as ectotherm animals. The climate warming may pose more serious threat to reptiles. Although the behavior effect and reproduction biology have been well studied, little information is available about the adaptation mechanisms of reptiles to temperature stress. In this study, the native Chinese species, Eremias argus were incubated at 15 (cold stress), 25 (control group) and 35 °C (thermal stress) for 24 h. The transcriptome and metabolome technology were applied to investigate the molecular regulation mechanisms of lizards to acute temperature changes. The CIRBP and HSPA8 were hub genes in response to temperature adaptation. The increased expression of PER gene in lizard circadian rhythm is associated with tyrosine metabolism after cold or thermal stress. The poly-unsaturated fatty acids in female lizard liver were significantly increased with up-regulation of FASN and ACACA genes after thermal stress, which proved the disruption of fatty acid biosynthesis pathway in corporation with the altered body weight. The cortisol and testosterone were important steroid hormones in response to temperature changes especially in male lizard liver. The increased CIRBP gene expression in lizard gonads suppressed the KDM6B gene, which regulates the testis development and may induce sex reversal in male lizard after thermal stress. The adaptation responses of lizards to temperature stress may threaten the health status of wild population.
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Affiliation(s)
- Jing Chang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China.
| | - Yifan Pan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China; University of Chinese Academy of Sciences, Yuquan RD 19 a, Beijing 100049, China
| | - Wentao Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China; University of Chinese Academy of Sciences, Yuquan RD 19 a, Beijing 100049, China
| | - Yun Xie
- Institute of Food Safety, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Weiyu Hao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China
| | - Peng Xu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China
| | - Yinghuan Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China
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7
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Megía-Palma R, Barja I, Barrientos R. Fecal glucocorticoid metabolites and ectoparasites as biomarkers of heat stress close to roads in a Mediterranean lizard. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149919. [PMID: 34525719 DOI: 10.1016/j.scitotenv.2021.149919] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/26/2021] [Accepted: 08/22/2021] [Indexed: 06/13/2023]
Abstract
Differences between air and ground temperatures are expected to narrow with the advance of the season in temperate regions (aka seasonal restriction in the availability of thermal microhabitats), which may activate behavioral and physiological responses of ectotherm species adapted to temperate climates. However, according to cost-benefit models of ectotherm thermoregulation, we hypothesize that these responses may also carry some costs. We quantified seasonal shifts in thermoregulatory precision, concentration of fecal glucocorticoid metabolites, and load of ectoparasites in a Mediterranean lizard, Psammodromus algirus. We also tested whether the proximity to a road, a putative source of chronic stress, can facilitate the glucocorticoid-mediated response of lizards to heat stress. As expected, differences between body and environmental temperatures narrowed during the reproductive season and lizards responded by increasing their thermoregulatory precision and the secretion of glucocorticoids, as indicated by metabolites in feces. Interestingly, lizards tended to have higher glucocorticoid concentration when captured far from the road. This might reflect either a putative impairment of the glucocorticoid-mediated response of the lizards to heat stress close to the road or the plastic capability of P. algirus to acclimate to sources of moderate chronic stress. In the latter direction, the increase of both glucocorticoid metabolites and thermoregulatory precision supported that this Mediterranean species responds to environmental thermal restrictions with adaptive behavioral and physiological mechanisms. However, this was also associated with an increase in its susceptibility to ectoparasites, which represents an added cost to the current cost-benefit models of ectotherm thermoregulation.
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Affiliation(s)
- R Megía-Palma
- Universidad de Alcalá (UAH), Parasitology Unit, Department of Biomedicine and Biotechnology, School of Pharmacy, Spain; CIBIO-InBIO: Research Center in Biodiversity and Genetic Resources, Portugal.
| | - I Barja
- Laboratory of Etho-Physiology, Department Biology (Unit Zoology), Autónoma University of Madrid, Spain; Research Centre in Biodiversity and Global Change (CIBC-UAM), Autónoma University of Madrid, Spain
| | - R Barrientos
- Road Ecology Lab, Department of Biodiversity, Ecology and Evolution, School of Biology, Complutense University of Madrid, Spain
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8
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Rousseau K, Dufour S, Sachs LM. Interdependence of Thyroid and Corticosteroid Signaling in Vertebrate Developmental Transitions. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.735487] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Post-embryonic acute developmental processes mainly allow the transition from one life stage in a specific ecological niche to the next life stage in a different ecological niche. Metamorphosis, an emblematic type of these post-embryonic developmental processes, has occurred repeatedly and independently in various phylogenetic groups throughout metazoan evolution, such as in cnidarian, insects, molluscs, tunicates, or vertebrates. This review will focus on metamorphoses and developmental transitions in vertebrates, including typical larval metamorphosis in anuran amphibians, larval and secondary metamorphoses in teleost fishes, egg hatching in sauropsids and birth in mammals. Two neuroendocrine axes, the hypothalamic-pituitary-thyroid and the hypothalamic-pituitary-adrenal/interrenal axes, are central players in the regulation of these life transitions. The review will address the molecular and functional evolution of these axes and their interactions. Mechanisms of integration of internal and environmental cues, and activation of these neuroendocrine axes represent key questions in an “eco-evo-devo” perspective of metamorphosis. The roles played by developmental transitions in the innovation, adaptation, and plasticity of life cycles throughout vertebrates will be discussed. In the current context of global climate change and habitat destruction, the review will also address the impact of environmental factors, such as global warming and endocrine disruptors on hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal/interrenal axes, and regulation of developmental transitions.
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9
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Scheun J, Campbell R, Ganswindt A, McIntyre T. Hot and bothered: alterations in faecal glucocorticoid metabolite concentrations of the sungazer lizard, Smaug giganteus, in response to an increase in environmental temperature. AFRICAN ZOOLOGY 2021. [DOI: 10.1080/15627020.2021.1980103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- J Scheun
- Department of Life and Consumer Sciences, University of South Africa, Pretoria, South Africa
- National Zoological Garden, South African National Biodiversity Institute, Pretoria, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - R Campbell
- National Zoological Garden, South African National Biodiversity Institute, Pretoria, South Africa
| | - A Ganswindt
- National Zoological Garden, South African National Biodiversity Institute, Pretoria, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - T McIntyre
- Department of Life and Consumer Sciences, University of South Africa, Pretoria, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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10
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Beyl HE, Jimeno B, Lynn SE, Breuner CW. Assay temperature affects corticosteroid-binding globulin and free corticosterone estimates across species. Gen Comp Endocrinol 2021; 310:113810. [PMID: 33964285 DOI: 10.1016/j.ygcen.2021.113810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/13/2021] [Accepted: 04/28/2021] [Indexed: 11/19/2022]
Abstract
Glucocorticoid hormones are often measured to assess how organisms physiologically respond to challenges in their environment. In plasma, glucocorticoids circulate in two forms: bound to corticosteroid-binding globulins (CBG) or unbound (free). Measuring CBG allows us to estimate the amount of free glucocorticoids present in a plasma sample. However, free glucocorticoid estimates are affected by the assay temperature used when measuring CBG, with colder temperatures maximizing specific binding but likely underestimating glucocorticoid's affinity for CBG. Here, we test how a biologically relevant incubation temperature (41 °C) changes the disassociation constant (Kd; used to estimate free glucocorticoid levels) when compared to the traditional 4 °C incubation temperature, across four commonly studied avian species. We then apply the new Kd's calculated at 41 °C to existing data sets to examine how the change in Kd affects free corticosterone estimates and data interpretation. Kd's were generally higher (lower affinity for CORT) at warmer incubation temperatures which resulted in higher levels of estimated free CORT in all four species but differed among subspecies. This increase in free CORT levels did not qualitatively change previously reported statistical relationships, but did affect variance and alpha (P) values. We suggest that future assays be run at biologically relevant temperatures for more accurate estimates of free CORT levels in vivo and to increase the chances of detecting biological patterns of free-CORT that may not be revealed with the classic methodology that tends to underestimate free CORT levels.
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Affiliation(s)
- Hannah E Beyl
- The Wildlife Biology Program, The University of Montana, 32 Campus Drive, HS 104, Missoula, MT 59801, United States.
| | - Blanca Jimeno
- Organismal Biology, Ecology, and Evolution, The University of Montana. 32 Campus Drive, HS 104, Missoula, MT 59801, United States
| | - Sharon E Lynn
- Department of Biology, The College of Wooster, 931 College Mall, Wooster, OH 44619, United States
| | - Creagh W Breuner
- The Wildlife Biology Program, The University of Montana, 32 Campus Drive, HS 104, Missoula, MT 59801, United States; Organismal Biology, Ecology, and Evolution, The University of Montana. 32 Campus Drive, HS 104, Missoula, MT 59801, United States
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11
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Holden KG, Gangloff EJ, Gomez-Mancillas E, Hagerty K, Bronikowski AM. Surviving winter: Physiological regulation of energy balance in a temperate ectotherm entering and exiting brumation. Gen Comp Endocrinol 2021; 307:113758. [PMID: 33771532 DOI: 10.1016/j.ygcen.2021.113758] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/24/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022]
Abstract
Characterizing the physiological response to prolonged cold exposure is essential for understanding the maintenance of long-term energy balance. As part of their natural life cycle, temperate ectotherms are often exposed to seasonal variation in temperatures, including extended periods of cold well below their activity range. Relatively little is known about variation in physiological responses as vertebrate ectotherms enter and exit brumation in response to sustained cold temperatures. We tested the influence of temperature on physiology before, during, and after a simulated brumation in the checkered garter snake (Thamnophis marcianus), a widespread ectothermic vertebrate. We tested for the relative effect of immediate temperature and physiological context (entering or exiting brumation) on hormones regulating energy balance, indicators of energy availability, and resting metabolic rate (V̇O2). Plasma corticosterone, glucose, and insulin, as well as immune cell heterophil: lymphocyte ratios responded to temperature, though they did so with different thermal response curves. Thermal sensitivity varied both among and within physiological measures depending on whether animals were going into or coming out of brumation. Additionally, V̇O2 was regulated beyond simple temperature-dependence, whereby post-brumation measures were depressed relative to pre-brumation measures at the same temperature. This pattern was characterized by a change in the temperature coefficient (Q10), with a larger pre-brumation Q10, suggesting reduced thermal sensitivity of metabolic rate following a period of extended cold exposure. The integrated physiological response presented here demonstrates not only temperature dependence across physiological axes, but seasonal variation in thermal responsiveness. Our results suggest that energy allocation decisions and hormonal regulation of underlying processes promote differing levels of thermal sensitivity when entering or exiting brumation.
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Affiliation(s)
- Kaitlyn G Holden
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
| | - Eric J Gangloff
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA; Department of Zoology, Ohio Wesleyan University, Delaware, OH 43015, USA
| | | | - Kelsi Hagerty
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Anne M Bronikowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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12
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Liu G, Cain K, Schwanz L. Maternal Temperature, Corticosterone, and Body Condition as Mediators of Maternal Effects in Jacky Dragons ( Amphibolurus muricatus). Physiol Biochem Zool 2021; 93:434-449. [PMID: 33104412 DOI: 10.1086/711955] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractTemperature is a crucial environmental component that imposes physiological constraints and ultimately produces variation in life-history traits. Temperatures experienced by mothers can influence offspring phenotypes, including growth and sex ratios, especially in ectothermic species. However, mechanisms by which thermal information can be passed onto offspring have been underexplored. Here, we investigated corticosterone as a potential mediator of thermal maternal effects. We held female jacky dragons (Amphibolurus muricatus) in two different thermal regimes (short [7 h] or long [11 h] basking treatments), then quantified plasma corticosterone levels and tested for correlations between the resulting corticosterone levels and reproductive outputs. Lizards in the long-bask treatment had significantly higher corticosterone levels than those in the short-bask treatment. Maternal corticosterone, in turn, had sex-dependent effects on offspring hatching size but was not associated with maternal reproductive effort or offspring sex or growth. In contrast, maternal body condition was strongly positively related to both reproductive output (including clutch size and total number of eggs) and offspring size at hatching but had no effect on offspring growth. Basking treatment also interacted with condition and corticosterone to affect egg mass and hatchling snout-vent length, respectively. When we tested for relationships between corticosterone levels and body condition, we found corticosterone to be negatively related to condition in long-bask lizards but only in the postbreeding season. These findings indicate that thermal opportunity alters physiology, with potential consequences for fitness. Moreover, the results suggest interactive influences of temperature, corticosterone, and condition as mediators of maternal effects.
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13
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Laid-back invaders: Cane toads (Rhinella marina) down-regulate their stress responses as they colonize a harsh climate. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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14
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Effects of temperature on plasma corticosterone in a native lizard. Sci Rep 2020; 10:16315. [PMID: 33004871 PMCID: PMC7530705 DOI: 10.1038/s41598-020-73354-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/15/2020] [Indexed: 12/30/2022] Open
Abstract
The glucocorticoid stress response is frequently used to indicate vertebrate response to the environment. Body temperature may affect glucocorticoid concentrations, particularly in ectotherms. We conducted lab manipulations and field measurements to test the effects of body temperature on plasma corticosterone (predominant glucocorticoid in reptiles) in eastern fence lizards (Sceloporus undulatus). First, we acclimated lizards to one of 4 treatments: 22 °C, 29 °C, 33 °C, or 36 °C, and measured cloacal temperatures and plasma corticosterone concentrations at baseline and after exposure to a standardized stressor (cloth bag). Both baseline and stress-induced corticosterone concentrations were lower in lizards with lower body temperatures. Second, we acclimated lizards to 22 °C or 29 °C and exposed them to a standardized (cloth bag) stressor for 3 to 41 min. Lizards acclimated to 29 °C showed a robust increase in plasma corticosterone concentrations with restraint stress, but those at 22 °C showed no such increases in corticosterone concentrations. Third, we measured lizards upon capture from the field. There was no correlation between body temperature and baseline plasma corticosterone in field-caught lizards. These results suggest body temperature can significantly affect plasma corticosterone concentrations in reptiles, which may be of particular concern for experiments conducted under laboratory conditions but may not translate to the field.
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15
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Hudson SB, Lidgard AD, French SS. Glucocorticoids, energy metabolites, and immunity vary across allostatic states for plateau side‐blotched lizards (
Uta stansburiana uniformis
) residing in a heterogeneous thermal environment. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:732-743. [DOI: 10.1002/jez.2415] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 08/17/2020] [Accepted: 09/08/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Spencer B. Hudson
- Department of Biology Utah State University Logan Utah USA
- Ecology Center Utah State University Logan Utah USA
| | | | - Susannah S. French
- Department of Biology Utah State University Logan Utah USA
- Ecology Center Utah State University Logan Utah USA
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16
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Abstract
The stress phenotype is multivariate. Recent advances have broadened our understanding beyond characterizing the stress response in a single dimension. Simultaneously, the toolbox available to ecophysiologists has expanded greatly in recent years, allowing the measurement of multiple biomarkers from an individual at a single point in time. Yet these advances-in our conceptual understanding and available methodologies-have not yet been combined in a unifying multivariate statistical framework. Here, we offer a brief review of the multivariate stress phenotype and describe a general statistical approach for analysis using nonparametric multivariate analysis of variance with residual randomization in permutation procedures (RRPP) implemented using the "RRPP" package in R. We also provide an example illustrating the novel insights that can be gained from a holistic multivariate approach to stress and provide a tutorial for how we analyzed these data, including annotated R code and a guide to interpretation of outputs (Online Appendix 1). We hope that this statistical methodology will provide a quantitative framework facilitating the unification of our theoretical understanding and empirical observations into a quantitative, multivariate theory of stress.
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Affiliation(s)
- Rory S Telemeco
- Department of Biology, California State University Fresno, Fresno, CA 93740, USA
| | - Eric J Gangloff
- Department of Zoology, Ohio Wesleyan University, Delaware, OH 43015, USA
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17
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Neuman-Lee LA, Hudson SB, Webb AC, French SS. Investigating the relationship between corticosterone and glucose in a reptile. ACTA ACUST UNITED AC 2020; 223:jeb.203885. [PMID: 31767736 DOI: 10.1242/jeb.203885] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 11/19/2019] [Indexed: 12/20/2022]
Abstract
The glucocorticoid hormone corticosterone (CORT) has classically been used in ecophysiological studies as a proxy for stress and energy mobilization, but rarely are CORT and the energy metabolites themselves concurrently measured. To examine CORT's role in mobilizing glucose in a wild reptile, we conducted two studies. The first study measured natural baseline and stress-induced blood-borne CORT and glucose levels in snakes during spring emergence and again when snakes return to the denning sites in autumn. The second study manipulated the hypothalamic-pituitary-adrenal (HPA) axis in male snakes in the autumn by taking a baseline blood sample, then subjecting individuals to one of five treatments (no injection, saline, CORT, adrenocorticotropin hormone and metyrapone). Subsequent samples were taken at 30 and 60 min. In both studies, we found that glucose levels do increase with acute stress, but that the relationship was not directly related to CORT elevation. In the second study, we found that none of the HPA axis manipulations directly affected blood glucose levels, further indicating that CORT may play a complex but not direct role in glucose mobilization in snakes. This study highlights the need for testing mechanisms in wild organisms by combining in situ observations with manipulative studies.
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Affiliation(s)
- Lorin A Neuman-Lee
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Spencer B Hudson
- Department of Biology, Utah State University, Logan, UT 84322, USA
| | - Alison C Webb
- Department of Biology, Utah State University, Logan, UT 84322, USA
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18
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Zena LA, Dillon D, Hunt KE, Navas CA, Buck CL, Bícego KC. Hormonal correlates of the annual cycle of activity and body temperature in the South-American tegu lizard (Salvator merianae). Gen Comp Endocrinol 2020; 285:113295. [PMID: 31580883 DOI: 10.1016/j.ygcen.2019.113295] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/19/2019] [Accepted: 09/29/2019] [Indexed: 01/29/2023]
Abstract
Life history transitions and hormones are known to interact and influence many aspects of animal physiology and behavior. The South-American tegu lizard (Salvator merianae) exhibits a profound seasonal shift in metabolism and body temperature, characterized by high daily activity during warmer months, including reproductive endothermy in spring, and metabolic suppression during hibernation in winter. This makes S. merianae an interesting subject for studies of interrelationships between endocrinology and seasonal changes in physiology/behavior. We investigated how plasma concentrations of hormones involved in regulation of energy metabolism (thyroid hormones T4 and T3; corticosterone) and reproduction (testosterone in males and estrogen/progesterone in females) correlate with activity and body temperature (Tb) across the annual cycle of captive held S. merianae in semi-natural conditions. In our initial model, thyroid hormones and corticosterone showed a positive relationship with activity and Tb with independent of sex: T3 positively correlated with activity and Tb, while T4 and corticosterone correlated positively with changes in Tb only. This suggests that thyroid hormones and glucocorticoids may be involved in metabolic transitions of annual cycle events. When accounting for sex-steroid hormones, our sex separated models showed a positive relationship between testosterone and Tb in males and progesterone and activity in females. Coupling seasonal endocrine measures with activity and Tb may expand our understanding of the relationship between animal's physiology and its environment. Manipulative experiments are required in order to unveil the directionality of influences existing among abiotic factors and the hormonal signaling of annual cyclicity in physiology/behavior.
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Affiliation(s)
- Lucas A Zena
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, Fairfax, VA, USA
| | - Carlos A Navas
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900 Jaboticabal, São Paulo, Brazil.
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19
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Telemeco RS, Simpson DY, Tylan C, Langkilde T, Schwartz TS. Contrasting Responses of Lizards to Divergent Ecological Stressors Across Biological Levels of Organization. Integr Comp Biol 2019; 59:292-305. [PMID: 31127305 DOI: 10.1093/icb/icz071] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
It is frequently hypothesized that animals employ a generalized "stress response," largely mediated by glucocorticoid (GC) hormones, such as corticosterone, to combat challenging environmental conditions. Under this hypothesis, diverse stressors are predicted to have concordant effects across biological levels of an organism. We tested the generalized stress response hypothesis in two complementary experiments with juvenile and adult male Eastern fence lizards (Sceloporus undulatus). In both experiments, animals were exposed to diverse, ecologically-relevant, acute stressors (high temperature or red imported fire ants, Solenopsis invicta) and we examined their responses at three biological levels: behavioral; physiological (endocrine [plasma corticosterone and blood glucose concentrations] and innate immunity [complement and natural antibodies]); and cellular responses (gene expression of a panel of five heat-shock proteins in blood and liver) at 30 or 90 min post stress initiation. In both experiments, we observed large differences in the cellular response to the two stressors, which contrasts the similar behavioral and endocrine responses. In the adult experiment for which we had innate immune data, the stressors affected immune function independently, and they were correlated with CORT in opposing directions. Taken together, these results challenge the concept of a generalized stress response. Rather, the stress response was context specific, especially at the cellular level. Such context-specificity might explain why attempts to link GC hormones with life history and fitness have proved difficult. Our results emphasize the need for indicators at multiple biological levels and whole-organism examinations of stress.
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Affiliation(s)
- Rory S Telemeco
- Department of Biology, California State University, Fresno, CA 93740, USA.,Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Dasia Y Simpson
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Catherine Tylan
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Tracy Langkilde
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA.,Intercollege Graduate Degree Program in Ecology, Pennsylvania State University, University Park, PA 16802, USA
| | - Tonia S Schwartz
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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20
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Selechnik D, Richardson MF, Shine R, DeVore JL, Ducatez S, Rollins LA. Increased Adaptive Variation Despite Reduced Overall Genetic Diversity in a Rapidly Adapting Invader. Front Genet 2019; 10:1221. [PMID: 31850072 PMCID: PMC6901984 DOI: 10.3389/fgene.2019.01221] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 11/05/2019] [Indexed: 01/26/2023] Open
Abstract
Invasive species often evolve rapidly following introduction despite genetic bottlenecks that may result from small numbers of founders; however, some invasions may not fit this “genetic paradox”. The invasive cane toad (Rhinella marina) displays high phenotypic variation across its introduced Australian range. Here, we used three genome-wide datasets to characterize their population structure and genetic diversity. We found that toads form three genetic clusters: 1) native range toads, 2) toads from the source population in Hawaii and long-established areas near introduction sites in Australia, and 3) toads from more recently established northern Australian sites. Although we find an overall reduction in genetic diversity following introduction, we do not see this reduction in loci putatively under selection, suggesting that genetic diversity may have been maintained at ecologically relevant traits, or that mutation rates were high enough to maintain adaptive potential. Nonetheless, toads encounter novel environmental challenges in Australia, and the transition between genetic clusters occurs at a point along the invasion transect where temperature rises and rainfall decreases. We identify environmentally associated loci known to be involved in resistance to heat and dehydration. This study highlights that natural selection occurs rapidly and plays a vital role in shaping the structure of invasive populations.
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Affiliation(s)
- Daniel Selechnik
- School of Life and Environmental Sciences (SOLES), University of Sydney, Sydney, NSW, Australia.,Evolution and Ecology Research Centre, School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Mark F Richardson
- Deakin Genomics Centre, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia.,Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia
| | - Richard Shine
- School of Life and Environmental Sciences (SOLES), University of Sydney, Sydney, NSW, Australia
| | - Jayna L DeVore
- School of Life and Environmental Sciences (SOLES), University of Sydney, Sydney, NSW, Australia
| | - Simon Ducatez
- School of Life and Environmental Sciences (SOLES), University of Sydney, Sydney, NSW, Australia
| | - Lee A Rollins
- Evolution and Ecology Research Centre, School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
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21
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The Adaptive Sex in Stressful Environments. Trends Ecol Evol 2019; 34:628-640. [PMID: 30952545 DOI: 10.1016/j.tree.2019.02.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 01/10/2023]
Abstract
The impact of early stress on juvenile development has intrigued scientists for decades, but the adaptive significance of such effects remains an ongoing debate. This debate has largely ignored some characteristics of the offspring, such as their sex, despite strong evolutionary and demographic implications of sex-ratio variation. We review recent studies that examine associations between glucocorticoids (GCs), the main class of stress hormones, and offspring sex. Whereas exposure to GCs at around the time of sex determination in fish consistently produces males, the extent and direction of sex-ratio bias in response to stress vary in reptiles, birds, and mammals. We propose proximate and ultimate explanations for most of these trends.
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22
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Fabrício-Neto A, Madelaire CB, Gomes FR, Andrade DV. Exposure to fluctuating temperatures leads to reduced immunity and to stress response in rattlesnakes. J Exp Biol 2019; 222:jeb.208645. [DOI: 10.1242/jeb.208645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/23/2019] [Indexed: 01/17/2023]
Abstract
Ectothermic organisms often experience considerable variation in their body temperature throughout the circadian cycle. However, studies focusing on the measurement of physiological traits are usually performed under constant temperature regimes. This mismatch between thermal exposure in the field and experimental conditions could act as a stressor agent, since physiological functions are strongly influenced by temperature. Herein, we asked the question whether constant thermal regimes would cause a stress response and impact the immunity of the South American rattlesnake (Crotalus durissus) when compared to a fluctuating thermal regime. We addressed this question by determining heterophil:lymphocyte ratio (H:L), plasma bacteria killing ability (BKA) and corticosterone levels (CORT) in snakes kept under a constant temperature regime at 30°C, and under a fluctuating regime that oscillated between 25°C at nighttime to 35°C at daytime. The experiments had a mirrored design, in which half of the snakes were subjected to a fluctuating-to-constant treatment, while the other half was exposed to a constant-to-fluctuating treatment. The shift from constant to fluctuating thermal regime was accompanied by an increase in plasma CORT levels indicating the activation of a stress response. Exposure to a fluctuating thermal regime at the onset of the experiments induced a decrease in the BKA of rattlesnakes. H:L was not affected by treatments and, therefore, the shift between thermal regimes seems to have acted as a low intensity stressor. Our results suggest that the removal from temperatures close to the snakés preferred body temperature triggers a stress response in rattlesnakes.
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Affiliation(s)
- Ailton Fabrício-Neto
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brazil
| | - Carla B. Madelaire
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-900, São Paulo, São Paulo, Brazil
| | - Fernando R. Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-900, São Paulo, São Paulo, Brazil
| | - Denis V. Andrade
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brazil
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23
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Lavin BR, Wogan GOU, McGuire JA, Feldman CR. Phylogeography of the Northern Alligator Lizard (Squamata, Anguidae): Hidden diversity in a western endemic. ZOOL SCR 2018. [DOI: 10.1111/zsc.12294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Brian R. Lavin
- Department of Biology; Sonoma State University; Rohnert Park California
| | - Guinevere O. U. Wogan
- Department of Environmental Science, Policy and Management and Museum of Vertebrate Zoology; University of California; Berkeley California
| | - Jimmy A. McGuire
- Department of Integrative Biology and Museum of Vertebrate Zoology; University of California; Berkeley California
| | - Chris R. Feldman
- Department of Biology and Program in Ecology, Evolution and Conservation Biology; University of Nevada; Reno Nevada
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24
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Lu HL, Wang J, Xu DD, Dang W. Maternal warming influences reproductive frequency, but not hatchling phenotypes in a multiple-clutched oviparous lizard. J Therm Biol 2018; 74:303-310. [PMID: 29801642 DOI: 10.1016/j.jtherbio.2018.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/29/2018] [Accepted: 04/29/2018] [Indexed: 11/16/2022]
Abstract
The understanding of life-history responses to increased temperature is helpful for evaluating the potential of species for tackling future climate change. Herein, adult southern grass lizards, Takydromus sexlineatus, were maintained under two thermal regimes simulating current thermal environment and a 4 °C warming scenario to determine the effects of experimental warming on female reproduction and offspring phenotypes. Experimental warming caused females to oviposit earlier and more frequently; however, it did not affect other reproductive traits, including clutch size, egg mass and clutch mass. Accelerated embryonic development and energy accumulation rate might have occurred in warmed females. Maternal warming appeared to increase early embryonic mortality, but did not shift hatchling size and locomotor performance. Embryos of oviparous lizards might be more vulnerable to climate change at early stages than at later stages. The impacts of climate change in oviparous lizards might be adverse in the longer term because of the shift in pre-ovipositional embryo viability, which possibly led to a decreased number of hatchlings.
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Affiliation(s)
- Hong-Liang Lu
- Hangzhou Key Laboratory for Animal Adaptation and Evolution, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, Zhejiang, China.
| | - Jie Wang
- Hangzhou Key Laboratory for Animal Adaptation and Evolution, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, Zhejiang, China
| | - Da-De Xu
- College of Life Sciences, Zhaoqing University, Zhaoqing 526061, Guangdong, China
| | - Wei Dang
- Hangzhou Key Laboratory for Animal Adaptation and Evolution, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, Zhejiang, China
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25
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Dupoué A, Rutschmann A, Le Galliard JF, Clobert J, Blaimont P, Sinervo B, Miles DB, Haussy C, Meylan S. Reduction in baseline corticosterone secretion correlates with climate warming and drying across wild lizard populations. J Anim Ecol 2018; 87:1331-1341. [PMID: 29701285 DOI: 10.1111/1365-2656.12843] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/12/2018] [Indexed: 12/25/2022]
Abstract
Climate change should lead to massive loss of biodiversity in most taxa, but the detailed physiological mechanisms underlying population extinction remain largely elusive so far. In vertebrates, baseline levels of hormones such as glucocorticoids (GCs) may be indicators of population state as their secretion to chronic stress can impair survival and reproduction. However, the relationship between GC secretion, climate change and population extinction risk remains unclear. In this study, we investigated whether levels of baseline corticosterone (the main GCs in reptiles) correlate with environmental conditions and associated extinction risk across wild populations of the common lizard Zootoca vivipara. First, we performed a cross-sectional comparison of baseline corticosterone levels along an altitudinal gradient among 14 populations. Then, we used a longitudinal study in eight populations to examine the changes in corticosterone levels following the exposure to a heatwave period. Unexpectedly, baseline corticosterone decreased with increasing thermal conditions at rest in females and was not correlated with extinction risk. In addition, baseline corticosterone levels decreased after exposure to an extreme heatwave period. This seasonal corticosterone decrease was more pronounced in populations without access to standing water. We suggest that low basal secretion of corticosterone may entail downregulating activity levels and limit exposure to adverse climatic conditions, especially to reduce water loss. These new insights suggest that rapid population decline might be preceded by a downregulation of the corticosterone secretion.
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Affiliation(s)
- Andréaz Dupoué
- CNRS, iEES Paris, UMR 7618, Sorbonne Université, Paris, France
| | - Alexis Rutschmann
- Station d'Ecologie Théorique et Expérimentale du CNRS à Moulis, UMR 5321, Saint Girons, France
| | - Jean François Le Galliard
- CNRS, iEES Paris, UMR 7618, Sorbonne Université, Paris, France.,Centre de recherche en écologie expérimentale et prédictive (CEREEP-Ecotron IleDeFrance), Ecole normale supérieure, CNRS, UMS 3194, PSL Research University, Saint-Pierre-lès-Nemours, France
| | - Jean Clobert
- Station d'Ecologie Théorique et Expérimentale du CNRS à Moulis, UMR 5321, Saint Girons, France
| | - Pauline Blaimont
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California
| | - Barry Sinervo
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California
| | - Donald B Miles
- Station d'Ecologie Théorique et Expérimentale du CNRS à Moulis, UMR 5321, Saint Girons, France.,Department of Biological Sciences, Ohio University, Athens, Ohio
| | - Claudy Haussy
- CNRS, iEES Paris, UMR 7618, Sorbonne Université, Paris, France
| | - Sandrine Meylan
- CNRS, iEES Paris, UMR 7618, Sorbonne Université, Paris, France.,ESPE de Paris, Sorbonne Université, Paris, France
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26
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Novarro AJ, Gabor CR, Goff CB, Mezebish TD, Thompson LM, Grayson KL. Physiological responses to elevated temperature across the geographic range of a terrestrial salamander. J Exp Biol 2018; 221:jeb.178236. [DOI: 10.1242/jeb.178236] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 07/31/2018] [Indexed: 01/18/2023]
Abstract
Widespread species often possess physiological mechanisms for coping with thermal heterogeneity, and uncovering these mechanisms provides insight into species responses to climate change. The emergence of non-invasive corticosterone (CORT) assays allows us to rapidly assess physiological responses to environmental change on a large scale. We lack, however, a basic understanding of how temperature affects CORT, and whether temperature and CORT interactively affect performance. Here, we examine the effects of elevated temperature on CORT and whole-organism performance in a terrestrial salamander, Plethodon cinereus, across a latitudinal gradient. Using water-borne hormone assays, we found that raising ambient temperature from 15 to 25°C increased CORT release at a similar rate for salamanders from all sites. However, CORT release rate was higher overall in the warmest, southernmost site. Elevated temperatures also affected physiological performance, but the effects differed among sites. Ingestion rate increased in salamanders from the warmer sites but remained the same for those from cooler sites. Mass gain was reduced for most individuals, though this reduction was more dramatic in salamanders from the cooler sites. We also found a temperature-dependent relationship between CORT and food conversion efficiency (i.e., the amount of mass gained per unit food ingested). CORT was negatively related to food conversion efficiency at 25°C but was unrelated at 15°C. Thus, the energetic gains of elevated ingestion rates may be counteracted by elevated CORT release rates experienced by salamanders in warmer environments. By integrating multiple physiological metrics, we highlight the complex relationships between temperature and individual responses to warming climates.
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Affiliation(s)
| | - Caitlin R. Gabor
- Department of Biology, Texas State University, San Marcos, TX 78666, USA
| | - Cory B. Goff
- Department of Biology, Texas State University, San Marcos, TX 78666, USA
| | - Tori D. Mezebish
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Lily M. Thompson
- Department of Biology, University of Richmond, Richmond, VA 23173, USA
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27
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Telemeco RS, Gangloff EJ, Cordero GA, Polich RL, Bronikowski AM, Janzen FJ. Physiology at near‐critical temperatures, but not critical limits, varies between two lizard species that partition the thermal environment. J Anim Ecol 2017; 86:1510-1522. [DOI: 10.1111/1365-2656.12738] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 07/22/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Rory S. Telemeco
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
- Department of Biology University of Washington Seattle WA USA
| | - Eric J. Gangloff
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
| | - Gerardo A. Cordero
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
- Department of Biology Lund University Lund Sweden
| | - Rebecca L. Polich
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
| | - Anne M. Bronikowski
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
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28
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Onorati M, Sancesario G, Pastore D, Bernardini S, Cruz M, Carrión JE, Carosi M, Vignoli L, Lauro D, Gentile G. Effects of parasitic infection and reproduction on corticosterone plasma levels in Galápagos land iguanas, Conolophus marthae and C. subcristatus. Ecol Evol 2017; 7:6046-6055. [PMID: 28808564 PMCID: PMC5551272 DOI: 10.1002/ece3.3077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 03/24/2017] [Accepted: 04/25/2017] [Indexed: 11/08/2022] Open
Abstract
In vertebrates, one main feature of stress response is the release of glucocorticoids (corticosterone in reptiles), steroid hormones whose synthesis is regulated by the hypothalamic-pituitary-adrenal axis (HPA). In the Galápagos Islands, populations of land iguanas are differentially impacted by a tick-transmitted apicomplexan hemoparasite of genus Hepatozoon, which could cause diseases and ultimately reduce fitness. Using competitive enzyme-linked immunosorbent assays (ELISA), we examined baseline plasma corticosterone levels of two syntopic and highly parasitized populations of the land iguana species Conolophus marthae and C. subcristatus in Wolf volcano (Isabela Island). We also used a poorly parasitized population of C. subcristatus from the same island (Bahia Urbina) as a reference. To better interpret the observed glucocorticoids patterns, we simultaneously performed the count of white blood cells (WBCs) in all individuals and investigated the reproductive status of females. We did not find evidence in support of either a positive or negative relationship between the tick load, hemoparasite infection, and glucocorticoid plasma concentration in C. marthae and C. subcristatus at Wolf volcano. The comparison between parasitized and non-parasitized sites (V. Wolf and Bahia Urbina) would instead suggest an inverse relationship between corticosterone and parasites. Our findings support association between corticosterone plasma levels and reproduction.
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Affiliation(s)
- Michela Onorati
- Department of Science University Roma Tre Rome Italy.,Direction of the Galápagos National Park Puerto Ayora, Santa Cruz Island, Galápagos Islands Ecuador
| | - Giulia Sancesario
- Department of Clinical and Behavioural Neurology IRCC S. Lucia Rome Italy
| | - Donatella Pastore
- Department of Systems Medicine University of Rome Tor Vergata Rome Italy
| | - Sergio Bernardini
- Department of Experimental Medicine and Surgery University of Rome Tor Vergata Rome Italy
| | - Marilyn Cruz
- Galápagos Genetics, Epidemiology and Pathology Laboratory Galápagos National Park & University of Guayaquil Puerto Ayora, Galápagos, Islands Ecuador
| | - Jorge E Carrión
- Direction of the Galápagos National Park Puerto Ayora, Santa Cruz Island, Galápagos Islands Ecuador
| | - Monica Carosi
- Department of Science University Roma Tre Rome Italy
| | | | - Davide Lauro
- Department of Systems Medicine University of Rome Tor Vergata Rome Italy
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29
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Stahlschmidt ZR, French SS, Ahn A, Webb A, Butler MW. A Simulated Heat Wave Has Diverse Effects on Immune Function and Oxidative Physiology in the Corn Snake (Pantherophis guttatus). Physiol Biochem Zool 2017; 90:434-444. [DOI: 10.1086/691315] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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30
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Anderson L, Nelson N, Cree A. Glucocorticoids in tuatara (Sphenodon punctatus): Some influential factors, and applications in conservation management. Gen Comp Endocrinol 2017; 244:54-59. [PMID: 26673869 DOI: 10.1016/j.ygcen.2015.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 11/23/2015] [Accepted: 12/02/2015] [Indexed: 11/16/2022]
Abstract
Glucocorticoid (GC) hormones promote basic life processes, regulate life-history transitions, and help individuals cope with challenges and stressors, thereby playing an important fitness role. Here, we review recent evidence for several factors that influence plasma concentrations of corticosterone (CORT), the main GC in tuatara (Sphenodon punctatus), and discuss the application of CORT as a physiological tool to monitor conservation efforts. Observational studies show an association between CORT concentrations and seasonal reproductive activity, ambient temperature, and ecological habitat parameters (including presence of rats/seabird abundance, sex-ratio, and genetic diversity), and experimental studies show a positive influence of acute temperature increase on the CORT response. Recently, CORT physiology has been applied as a monitoring tool in tuatara translocation programmes. No signs of chronic stress in CORT profiles were observed during standard short- and long-term translocation and rat eradication procedures, giving confidence that current conservation efforts are supportive in population recovery. These results provide a foundation for comparative understanding of stress physiology in reptiles, and will be critical for managing future population viability of tuatara in a changing environment.
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Affiliation(s)
- Lindsay Anderson
- Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand.
| | - Nicola Nelson
- Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand.
| | - Alison Cree
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
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Lorioux S, Angelier F, Lourdais O. Are glucocorticoids good indicators of pregnancy constraints in a capital breeder? Gen Comp Endocrinol 2016; 232:125-33. [PMID: 27090427 DOI: 10.1016/j.ygcen.2016.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 03/31/2016] [Accepted: 04/09/2016] [Indexed: 12/24/2022]
Abstract
Pregnancy imposes a substantial energetic demand on the mother (i.e. metabolic costs of pregnancy) and is often associated with modified maternal behavior and increased physical burdens that make females more vulnerable to predation. The Hypothalamic-Pituitary-Adrenal axis plays a fundamental role in reproduction through hormonal control of energy regulation and parental care. Therefore, evaluating the changes in baseline and stress-induced glucocorticoid levels in response to pregnancy may provide a robust tool to assess not only the constraints of gestation but also the way females may adjust to these constraints. In this study, we measured baseline and stress-induced corticosterone (CORT) concentrations in pregnant and non-pregnant aspic vipers (Vipera aspis), which are capital breeders. We also measured muscle condition (tail width) and locomotion performance (traction force) because these are robust proxies of protein mobilization associated with fasting. Baseline CORT concentration increased significantly over time in pregnant females, while they were lower and stable in non-reproductive females. Pregnant females had lower muscle condition at the onset of the study and tail width was negatively correlated with CORT concentration in this group. Contrary to our prediction, the stress response was not attenuated in pregnant females, but was proportional to baseline CORT concentration. Our results suggest that baseline CORT variations are closely related to energy constraints and structural protein mobilization in this capital breeder.
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Affiliation(s)
- Sophie Lorioux
- Centre d'Etudes Biologiques de Chizé, CNRS UPR 1934, 79360 Villiers en Bois, France; Université de Poitiers, 40 Avenue du recteur Pineau, 85022 Poitiers, France; School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS UPR 1934, 79360 Villiers en Bois, France
| | - Olivier Lourdais
- Centre d'Etudes Biologiques de Chizé, CNRS UPR 1934, 79360 Villiers en Bois, France; School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
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Brischoux F, Dupoué A, Lourdais O, Angelier F. Effects of mild wintering conditions on body mass and corticosterone levels in a temperate reptile, the aspic viper ( Vipera aspis ). Comp Biochem Physiol A Mol Integr Physiol 2016; 192:52-6. [DOI: 10.1016/j.cbpa.2015.11.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/20/2015] [Accepted: 11/23/2015] [Indexed: 11/24/2022]
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Gangloff EJ, Holden KG, Telemeco RS, Baumgard LH, Bronikowski AM. Hormonal and metabolic responses to upper temperature extremes in divergent life-history ecotypes of a garter snake. J Exp Biol 2016; 219:2944-2954. [DOI: 10.1242/jeb.143107] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/15/2016] [Indexed: 01/03/2023]
Abstract
Extreme temperatures constrain organismal physiology and impose both acute and chronic effects. Additionally, temperature-induced hormone-mediated stress response pathways and energetic trade-offs are important drivers of life-history variation. This study employs an integrative approach to quantify acute physiological responses to high temperatures in divergent life-history ecotypes of the western terrestrial garter snake (Thamnophis elegans). Using wild-caught animals, we measured oxygen consumption rate and physiological markers of hormonal stress response, energy availability, and anaerobic respiration in blood plasma across five ecologically relevant temperatures (24, 28, 32, 35, and 38° C; 3-hour exposure). Corticosterone, insulin, and glucose concentrations all increased with temperature, but with different thermal response curves, suggesting that high temperatures differently affect energy-regulation pathways. Additionally, oxygen consumption rate increased without plateau and lactate concentration did not increase with temperature, challenging the recent hypothesis that oxygen limitation sets upper thermal tolerance limits. Finally, animals had similar physiological thermal responses to high-temperature exposure regardless of genetic background, suggesting that local adaptation has not resulted in fixed differences between ecotypes. Together, these results identify some of the mechanisms by which higher temperatures alter hormonal-mediated energy balance in reptiles and potential limits to the flexibility of this response.
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Affiliation(s)
- Eric J. Gangloff
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Kaitlyn G. Holden
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Rory S. Telemeco
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
- Present Address: Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Lance H. Baumgard
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA
| | - Anne M. Bronikowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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Hunt KE, Innis CJ, Merigo C, Rolland RM. Endocrine responses to diverse stressors of capture, entanglement and stranding in leatherback turtles (Dermochelys coriacea). CONSERVATION PHYSIOLOGY 2016; 4:cow022. [PMID: 27413532 PMCID: PMC4941596 DOI: 10.1093/conphys/cow022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/01/2016] [Accepted: 05/07/2016] [Indexed: 05/10/2023]
Abstract
Leatherback turtles (Dermochelys coriacea) are exposed to many anthropogenic stressors, yet almost no data on stress physiology exist for this species. As a first step toward understanding the physiological responses of leatherback turtles to stress, and with the particular goal of assessment of the effect of capture, we quantified corticosterone (an adrenal stress hormone) and thyroxine (a regulator of metabolic rate, often inhibited by chronic stress) in 17 healthy leatherback turtles captured at sea for scientific study, with comparisons to 15 'distressed' leatherbacks that were found entangled in fishing gear (n = 8), confined in a weir net (n = 1) or stranded on shore (n = 6). Distressed leatherbacks had significantly elevated corticosterone (mean ± SEM 10.05 ± 1.72 ng/ml, median 8.38 ng/ml) and free thyroxine (mean 0.86 ± 0.37 pg/ml, median 0.08 pg/ml) compared with healthy leatherbacks sampled immediately before release (after ∼40 min of handling; corticosterone, mean 4.97 ± 0.62 ng/ml, median 5.21 ng/ml; and free thyroxine, mean 0.05 ± 0.05 pg/ml, median 0.00 pg/ml). The elevated thyroxine in distressed turtles compared with healthy turtles might indicate an energetic burden of entanglement and stranding. Six of the healthy leatherbacks were sampled twice, at ∼25 and ∼50 min after the time of first disturbance. In all six individuals, corticosterone was higher in the later sample (earlier sample, mean 2.74 ± 0.88 ng/ml, median 2.61 ng/ml; later sample, mean 5.43 ± 1.29 ng/ml, median 5.38 ng/ml), indicating that capture and handling elicit an adrenal stress response in this species. However, the corticosterone elevation after capture appeared relatively mild compared with the corticosterone concentrations of the entangled and stranded turtles. The findings suggest that capture and handling using the protocols described (e.g. capture duration <1 h) might represent only a mild stressor, whereas entanglement and stranding might represent moderate to severe stressors.
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Affiliation(s)
- Kathleen E. Hunt
- John H. Prescott Marine Laboratory, Research Department, New England Aquarium, Boston, MA 02110, USA
- Corresponding author: New England Aquarium, Central Wharf, Boston, MA 02110, USA. Tel: +1 503 501 8380.
| | - Charles J. Innis
- Animal Health Department, New England Aquarium, Boston, MA 02110, USA
| | - Constance Merigo
- Rescue and Rehabilitation Department, New England Aquarium, Boston, MA 02110, USA
| | - Rosalind M. Rolland
- John H. Prescott Marine Laboratory, Research Department, New England Aquarium, Boston, MA 02110, USA
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