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Rovegno E, Lucon-Xiccato T, Terrin F, Valle LD, Bertolucci C. Knockout in zebrafish reveals the role of the glucocorticoid receptor in shaping behavioral syndromes. Behav Brain Res 2024; 473:115179. [PMID: 39103124 DOI: 10.1016/j.bbr.2024.115179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/03/2024] [Accepted: 08/02/2024] [Indexed: 08/07/2024]
Abstract
Glucocorticoids (GCs) have a wide spectrum of effects on animal behavior. A recently suggested effect involves determining the structure of individual differences, that is how the behavioral traits of an individual covary, forming the so-called behavioral syndromes. As GCs can exert their action in multiple ways, e.g., via rapid non-genomic effects or via the activation of two highly homologous members of the steroid receptor family acting as transcription factors, it is unclear how the GC modulation of behavioral syndromes takes place. We exploited a zebrafish line with a frameshift mutation in the gene encoding the GC receptor (Gr), to investigate this question. We found that lack of Gr altered the average score of several behavioral traits in the mutant line, determining reduced boldness, and increased activity and sociability. Critically, the pattern of covariation between these traits was also substantially affected by the loss of Gr. The most evident effect was an association of traits involved in boldness in the gr mutant line. This study reveals that, in zebrafish, Gr is not only involved in the modulation of the average value of behavioral traits, but also in how the behavioral traits of an individual are interrelated and determine the behavioral syndromes.
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Affiliation(s)
- Eleonora Rovegno
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
| | - Tyrone Lucon-Xiccato
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | | | | | - Cristiano Bertolucci
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
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2
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de Almeida Prado DM, de Figueiredo AC, Lima AS, Gomes FR, Madelaire CB. Corticosterone treatment results in fat deposition and body mass maintenance without effects on feeding behaviour or immunity in female lizards (Tropidurus catalanensis). Comp Biochem Physiol A Mol Integr Physiol 2024; 297:111712. [PMID: 39084515 DOI: 10.1016/j.cbpa.2024.111712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 08/02/2024]
Abstract
Throughout life, animals must maintain homeostasis while coping with challenging events. The period after reproduction can be challenging for oviparous females to maintain homeostasis since they direct most of their energy stores to vitellogenesis, possibly increasing the vulnerability to stressors. Changes in glucocorticoids' (GC) secretion promote various behavioural and physiological adjustments daily and to restore balance after facing stressors. However, when GC are elevated for extended periods, which usually occurs in response to chronic exposure to stressors, they can affect feeding behaviour and suppress the immune function. We aim to elucidate the effects of chronic corticosterone (CORT) exposure on feeding behaviour, body condition and immune function in female lizards, Tropidurus catalanensis, in the post-reproductive period. Thirty animals were divided into three groups: 1. Control (no experimental procedure performed); 2. Empty Implant (animals implanted with empty silastic tube); and 3. CORT Implant (animals implanted with silastic tube filled with CORT, with a chronic continuous release for at least a week). CORT plasma levels feeding behaviour, body condition (body index [BI] and fat index [FI]), leukocyte count, and several immune function variables (bacterial killing ability [BKA], hemagglutination titer, phytohemagglutinin [PHA] immune challenge and leukocyte count) were evaluated. After implantation, CORT treated animals maintained stable body mass through the experiment, while Control and Empty Implant groups displayed weight loss. In the CORT treated animals, there was also a positive relation between BI and FI, and higher FI when compared to groups 1 and 2. No effects of CORT were observed on feeding behaviour nor on the immune function.
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Affiliation(s)
- Débora Meyer de Almeida Prado
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, Travessa 14, n° 321, Cidade Universitária, São Paulo, SP 05508090, Brazil.
| | - Aymam Cobo de Figueiredo
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, Travessa 14, n° 321, Cidade Universitária, São Paulo, SP 05508090, Brazil
| | - Alan Siqueira Lima
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, Travessa 14, n° 321, Cidade Universitária, São Paulo, SP 05508090, Brazil
| | - Fernando Ribeiro Gomes
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, Travessa 14, n° 321, Cidade Universitária, São Paulo, SP 05508090, Brazil
| | - Carla Bonetti Madelaire
- Beckman Center for Conservation Research, San Diego Zoo Wildlife Alliance, Escondido, CA 92027, United States. https://twitter.com/carlamadelaire
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3
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Lalande LD, Bourgoin G, Carbillet J, Cheynel L, Debias F, Ferté H, Gaillard JM, Garcia R, Lemaître JF, Palme R, Pellerin M, Peroz C, Rey B, Vuarin P, Gilot-Fromont E. Early-life glucocorticoids accelerate lymphocyte count senescence in roe deer. Gen Comp Endocrinol 2024; 357:114595. [PMID: 39059616 DOI: 10.1016/j.ygcen.2024.114595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 07/11/2024] [Accepted: 07/20/2024] [Indexed: 07/28/2024]
Abstract
Immunosenescence corresponds to the progressive decline of immune functions with increasing age. Although it is critical to understand what modulates such a decline, the ecological and physiological drivers of immunosenescence remain poorly understood in the wild. Among them, the level of glucocorticoids (GCs) during early life are good candidates to modulate immunosenescence patterns because these hormones can have long-term consequences on individual physiology. Indeed, GCs act as regulators of energy allocation to ensure allostasis, are part of the stress response triggered by unpredictable events and have immunosuppressive effects when chronically elevated. We used longitudinal data collected over two decades in two populations of roe deer (Capreolus capreolus) to test whether higher baseline GC levels measured within the first year of life were associated with a more pronounced immunosenescence and parasite susceptibility. We first assessed immunosenescence trajectories in these populations facing contrasting environmental conditions. Then, we found that juvenile GC levels can modulate lymphocyte trajectory. Lymphocyte depletion was accelerated late in life when GCs were elevated early in life. Although the exact mechanism remains to be elucidated, it could involve a role of GCs on thymic characteristics. In addition, elevated GC levels in juveniles were associated with a higher abundance of lung parasites during adulthood for individuals born during bad years, suggesting short-term negative effects of GCs on juvenile immunity, having in turn long-lasting consequences on adult parasite load, depending on juvenile environmental conditions. These findings offer promising research directions in assessing the carry-over consequences of GCs on life-history traits in the wild.
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Affiliation(s)
- Lucas D Lalande
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France.
| | - Gilles Bourgoin
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France; Université de Lyon, VetAgro Sup, 69280 Marcy l'Etoile, France
| | - Jeffrey Carbillet
- Institute of Ecology and Earth Sciences, University of Tartu, 51014 Tartu, Estonia
| | - Louise Cheynel
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire d'Écologie des Hydrosystèmes Naturels et Anthropisés UMR 5023, F-69622 Villeurbanne, France
| | - François Debias
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Hubert Ferté
- Université de Reims, Épidémio-Surveillance et Circulation de Parasites dans les Environnements UR 7510, 55100 Reims, France
| | - Jean-Michel Gaillard
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Rebecca Garcia
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Jean-François Lemaître
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Maryline Pellerin
- Office Français de la Biodiversité, Direction de la Recherche et de l'Appui Scientifique, Service Conservation et Gestion Durable des Espèces Exploités, 52210 Châteauvillain, France
| | - Carole Peroz
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France; Université de Lyon, VetAgro Sup, 69280 Marcy l'Etoile, France
| | - Benjamin Rey
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Pauline Vuarin
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Emmanuelle Gilot-Fromont
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France; Université de Lyon, VetAgro Sup, 69280 Marcy l'Etoile, France.
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Surber-Cunningham LL, Jimenez LS, Mobo LW, Westrick SE, Fischer EK. Early development of the glucocorticoid stress response in poison frog tadpoles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.31.596457. [PMID: 38895357 PMCID: PMC11185533 DOI: 10.1101/2024.05.31.596457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
In vertebrates, the glucocorticoid response through the hypothalamic-pituitary-adrenal (HPA) axis controls many essential functions, including behavior, metabolism, and ontogenetic transitions. However, there are tradeoffs associated with high levels of glucocorticoids, including reduced growth rate and lowered immunity. These tradeoffs drive variation in the timing of the development of the HPA axis across taxa. In anurans (frogs and toads), corticosterone has critical roles in development and behavior, and concentrations can fluctuate in response to environmental stressors. Given the role of corticosterone in ontogenetic changes and behaviors, we hypothesized that species with immediate habitat transitions and challenges would develop an HPA axis early in development. To test this hypothesis, we studied tadpoles of the dyeing poison frog ( Dendrobates tinctorius ), a species in which tadpoles hatch terrestrially and are transported to pools of water by their parent. We measured the excretion rate and whole-body concentration of corticosterone and the corticosterone response to adrenocorticotropic hormone (ACTH). We found no significant differences in excretion rates and whole-body concentration of corticosterone, nor physiological response to ACTH injection across tadpole development. These findings indicate that the glucocorticoid response is developed early in ontogeny. These findings generally differ from those found in other species of tadpoles, which may suggest the unique ecological pressures of D. tinctorius has shaped the development of its HPA axis. More broadly, this study illustrates how life history strategies and tradeoffs of glucocorticoids impact the timing of the development of the HPA axis. Highlights The timing of HPA axis development differs across species. We studied the HPA axis across tadpole development in Dendrobates tinctorius . No difference in corticosterone concentration across development.No difference in corticosterone response to ACTH across development.Results suggest an early developed HPA axis is essential for their life history.
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5
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Betancourth-Cundar M, Canoine V, Fusani L, Cadena CD. Does testosterone underly the interplay between male traits and territorial behavior in neotropical poison frogs? Horm Behav 2024; 162:105547. [PMID: 38677262 DOI: 10.1016/j.yhbeh.2024.105547] [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: 08/21/2023] [Revised: 02/24/2024] [Accepted: 04/12/2024] [Indexed: 04/29/2024]
Abstract
The ability of individual animals to defend a territory as well as various phenotypic and behavioral traits may be targets of sexual selection used by males to evaluate their competitors or by females to choose males. A frequent question in animal behavior is whether male traits and characteristics of their territory are correlated and what are the mechanisms that may mediate such associations when they exist. Because hormones link phenotype to behavior, by studying the role of testosterone in territoriality one may come closer to understanding the mechanisms mediating correlations or lack thereof between characteristics of territories and of males. We evaluated whether variation in characteristics of territories (size and quality) are correlated with variation in morphology, coloration, testosterone, heterozygosity, and calls in two species of poison frogs. The Amazonian frog Allobates aff. trilineatus exhibits male care and defends territories only during the breeding season, while the endangered frog Oophaga lehmanni displays maternal care and defends territories throughout the year. We found that morphological traits (body length, weight, thigh size), call activity, and testosterone levels correlated with size and various indicators of quality of the territory. However, the direction of these correlations (whether positive or negative) and which specific morphological, acoustic traits or testosterone level variables covaried depended on the species. Our findings highlight an endocrine pathway as part of the physiological machinery that may underlie the interplay between male traits and territorial behavior. We were able to identify some male traits related to territory attributes, but whether females choose males based on these traits requires further research.
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Affiliation(s)
| | - Virginie Canoine
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria
| | - Leonida Fusani
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
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Abraham ME, Robison CI, Serpa PBS, Strandberg NJ, Erasmus MA, Fraley GS, Erf GF, Karcher DM. Cage-Free Pullets Minimally Affected by Stocking Density Stressors. Animals (Basel) 2024; 14:1513. [PMID: 38791730 PMCID: PMC11117258 DOI: 10.3390/ani14101513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/03/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
Management choices during the pullet phase can affect behavior, welfare, and health later in life, but few studies have evaluated the pullet phase, particularly in extensive housing systems. This study was a 2 × 2 factorial randomized complete block design (RCBD) with two strains and two stocking densities. The Lohmann LB-Lite and Lohmann LSL-Lite were housed on the floor at high-stocking density (619-670 cm2/bird) and low-stocking density (1249-1352 cm2/bird), which changed with age from 2 to 16 weeks of age (WOA). Bird-based measures of appearance, blood parameters, organ measurements, and production values were evaluated. Stocking density alone affected (p < 0.05) only relative bursal weight (% of body weight)-3.32% in the low-density versus 3.08% in the high-density group. High-stocking density was correlated with decreased uniformity (high-89.33 ± 0.24%; low-90.41 ± 0.24; p < 0.02) and worse feather coverage in the brown strain. High-stocking density was correlated with greater uniformity (High-90.39 ± 0.24%; Low-88.47 ± 0.24%; p < 0.001) and better feather coverage in the white strain. This study's feed conversion ratio (FCR) was improved by 0.07 in the low-stocking density for both strains. The remaining parameters were affected by strain and age only. Thus, while stocking density effects vary slightly depending on the strain used, cage-free pullets had limited negative effects at both the high and low-stocking densities tested in this study; there were few to no changes in the numerous bird-based welfare parameters tested.
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Affiliation(s)
- Meagan E. Abraham
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-2050, USA; (M.E.A.); (M.A.E.); (G.S.F.)
| | - Cara I. Robison
- Department of Animal Sciences, Michigan State University, East Lansing, MI 48824-2604, USA;
| | - Priscila B. S. Serpa
- Department of Biomedical Sciences and Pathobiology, VA-MD College of Veterinary Medicine, Blacksburg, VA 24061, USA; (P.B.S.S.); (N.J.S.)
| | - Natalia J. Strandberg
- Department of Biomedical Sciences and Pathobiology, VA-MD College of Veterinary Medicine, Blacksburg, VA 24061, USA; (P.B.S.S.); (N.J.S.)
| | - Marisa A. Erasmus
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-2050, USA; (M.E.A.); (M.A.E.); (G.S.F.)
| | - Gregory S. Fraley
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-2050, USA; (M.E.A.); (M.A.E.); (G.S.F.)
| | - Gisela F. Erf
- Department of Poultry Science, System Division of Agriculture, University of Arkansas, Fayetteville, AR 72701, USA;
| | - Darrin M. Karcher
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-2050, USA; (M.E.A.); (M.A.E.); (G.S.F.)
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7
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Mentesana L, Casagrande S, Hau M. Baseline glucocorticoids alone do not predict reproductive success across years, but in interaction with enzymatic antioxidants. Ecol Evol 2024; 14:e11193. [PMID: 38571797 PMCID: PMC10985372 DOI: 10.1002/ece3.11193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 02/14/2024] [Accepted: 03/12/2024] [Indexed: 04/05/2024] Open
Abstract
Glucocorticoids are known to adjust organismal functions, such as metabolism, in response to environmental conditions. Therefore, these hormones are thought to play a key role in regulating the metabolically demanding aspects of reproduction, especially in variable environments. However, support for the hypothesis that variation in glucocorticoid concentrations predicts reproductive success is decidedly mixed. Two explanations may account for this discrepancy: (i) Glucocorticoids might not act independently but could interact with other physiological traits, jointly influencing reproduction, and (ii) such an association could become apparent primarily in challenging environments when glucocorticoid concentrations increase. To address these two possibilities, we determined natural variation in circulating baseline glucocorticoid concentrations in parental great tits (Parus major) alongside two physiological systems known to be related with an individual's metabolism: oxidative status parameters (i.e., concentrations of pro-oxidants, dietary, and enzymatic antioxidants) and body condition. These systems interact with glucocorticoids and can also influence reproductive success. We measured these variables in two breeding seasons that differed in environmental conditions. When accounting for the interaction of baseline glucocorticoids with other physiological traits, we found a positive relationship between baseline glucocorticoids and the number of fledglings in adult great tits. The strength of this relationship was more pronounced for those individuals who also had high concentrations of the enzymatic antioxidant glutathione peroxidase. When studied independently, glucocorticoids were not related to fitness proxies, even in the year with more challenging environmental conditions. Together, our study lend to support the hypothesis that glucocorticoids do not influence fitness alone, but in association with other physiological systems.
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Affiliation(s)
- Lucia Mentesana
- Max Planck Institute for Biological IntelligenceSeewiesenGermany
| | | | - Michaela Hau
- Max Planck Institute for Biological IntelligenceSeewiesenGermany
- University of KonstanzKonstanzGermany
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8
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Rodriguez-Santiago M, Ruppert A, Gall MD, Hoke K, Bee MA, Baugh AT. In your CORT: Corticosterone and its receptors in the brain underlie mate choosiness in female Cope's gray treefrogs (Hyla chrysoscelis). Horm Behav 2024; 159:105477. [PMID: 38245919 DOI: 10.1016/j.yhbeh.2024.105477] [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: 07/05/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/23/2024]
Abstract
Selecting an attractive mate can involve trade-offs related to investment in sampling effort. Glucocorticoids like corticosterone (CORT) are involved in resolving energetic trade-offs. However, CORT is rarely studied in the context of mate choice, despite its elevated levels during reproductive readiness and the energetic transitions that characterize reproduction. Few systems are as well suited as anuran amphibians to evaluate how females resolve energetic trade-offs during mate choice. Phonotaxis tests provide a robust bioassay of mate choice that permit the precise measurement of inter-individual variation in traits such as choosiness-the willingness to pursue the most attractive mate despite costs. In Cope's gray treefrogs (Hyla chrysoscelis), females exhibit remarkable variation in circulating CORT as well as choosiness during mate choice, and a moderate dose of exogenous CORT rapidly (<1 h) and reliably induce large increases in choosiness. Here we measured the expression of glucocorticoid (GR) and mineralocorticoid (MR) receptors in the brains of females previously treated with exogenous CORT and tested for mate choosiness. We report a large decrease in GR expression in the hindbrain and midbrain of females that were treated with the moderate dosage of CORT-the same treatment group that exhibited a dramatic increase in choosiness following CORT treatment. This association, however, does not appear to be causal, as only forebrain GR levels, which are not affected by CORT injection, are positively associated with variation in choosiness. No strong effects were found for MR. We discuss these findings and suggest future studies to test the influence of glucocorticoids on mate choice.
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Affiliation(s)
| | - Annika Ruppert
- Department of Ecology, Evolution, and Behavior, University of Minnesota - Twin Cities, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Megan D Gall
- Department of Biology, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604, USA
| | - Kim Hoke
- Department of Biology, Colorado State University, 200 W Lake St., Fort Collins, CO 80523, USA
| | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota - Twin Cities, 1479 Gortner Ave, St. Paul, MN 55108, USA; Graduate Program in Neuroscience, University of Minnesota - Twin Cities, 321 Church Street SE, Minneapolis, MN 55455, USA
| | - Alexander T Baugh
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
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Casagrande S, Dzialo M, Trost L, Malkoc K, Sadowska ET, Hau M, Pierce B, McWilliams S, Bauchinger U. Mitochondrial metabolism in blood more reliably predicts whole-animal energy needs compared to other tissues. iScience 2023; 26:108321. [PMID: 38025793 PMCID: PMC10679813 DOI: 10.1016/j.isci.2023.108321] [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: 07/04/2023] [Revised: 09/18/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Understanding energy metabolism in free-ranging animals is crucial for ecological studies. In birds, red blood cells (RBCs) offer a minimally invasive method to estimate metabolic rate (MR). In this study with European starlings Sturnus vulgaris, we examined how RBC oxygen consumption relates to oxygen use in key tissues (brain, liver, heart, and pectoral muscle) and versus the whole organism measured at basal levels. The pectoral muscle accounted for 34%-42% of organismal MR, while the heart and liver, despite their high mass-specific metabolic rate, each contributed 2.5%-3.0% to organismal MR. Despite its low contribution to organismal MR (0.03%-0.04%), RBC MR best predicted organismal MR (r = 0.70). Oxygen consumption of the brain and pectoralis was also associated with whole-organism MR, unlike that of heart and liver. Overall, our findings demonstrate that the metabolism of a systemic tissue like blood is a superior proxy for organismal energy metabolism than that of other tissues.
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Affiliation(s)
- Stefania Casagrande
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, 82319 Seewiesen, Germany
| | - Maciej Dzialo
- Jagiellonian University, Institute of Environmental Sciences, 30-387 Kraków, Poland
| | - Lisa Trost
- Max Planck Institute for Biological Intelligence, Department for Behavioral Neurobiology, 82319 Seewiesen, Germany
| | - Kasja Malkoc
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, 82319 Seewiesen, Germany
| | | | - Michaela Hau
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, 82319 Seewiesen, Germany
- University of Konstanz, Department of Biology, 78464 Konstanz, Germany
| | - Barbara Pierce
- Sacred Heart University, Department of Biology, Fairfield, CT 06825, USA
| | - Scott McWilliams
- University of Rhode Island, Department of Natural Resources Science, Kingston, RI 02881, USA
| | - Ulf Bauchinger
- Jagiellonian University, Institute of Environmental Sciences, 30-387 Kraków, Poland
- Nencki Institute of Experimental Biology, PAS, 02-093 Warsaw, Poland
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10
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LaDage LD, McCormick GL, Robbins TR, Longwell AS, Langkilde T. The effects of early-life and intergenerational stress on the brain. Proc Biol Sci 2023; 290:20231356. [PMID: 38018110 PMCID: PMC10685117 DOI: 10.1098/rspb.2023.1356] [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: 06/16/2023] [Accepted: 11/07/2023] [Indexed: 11/30/2023] Open
Abstract
Stress experienced during ontogeny can have profound effects on the adult phenotype. However, stress can also be experienced intergenerationally, where an offspring's phenotype can be moulded by stress experienced by the parents. Although early-life and intergenerational stress can alter anatomy, physiology, and behaviour, nothing is known about how these stress contexts interact to affect the neural phenotype. Here, we examined how early-life and intergenerational stress affect the brain in eastern fence lizards (Sceloporus undulatus). Some lizard populations co-occur with predatory fire ants, and stress from fire ant attacks exerts intergenerational physiological and behavioural changes in lizards. However, it is unclear if intergenerational stress, or the interaction between intergenerational and early-life stress, modulates the brain. To test this, we captured gravid females from fire ant invaded and uninvaded populations, and subjected offspring to three early-life stress treatments: (1) fire ant attack, (2) corticosterone, or (3) a control. Corticosterone and fire ant attack decreased some aspects of the neural phenotype while population of origin and the interaction of early-life stress and population had no effects on the brain. These results suggest that early-life stressors may better predict adult brain variation than intergenerational stress in this species.
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Affiliation(s)
- Lara D. LaDage
- Division of Mathematics & Natural Sciences, Penn State Altoona, 3000 Ivyside Dr., Altoona, PA 16601, USA
| | - Gail L. McCormick
- Eberly College of Science, Pennsylvania State University, University Park, PA 16802, USA
| | - Travis R. Robbins
- Department of Biology, University of Nebraska Omaha, 6001 Dodge St., Omaha, NE 68182, USA
| | - Anna S. Longwell
- Division of Mathematics & Natural Sciences, Penn State Altoona, 3000 Ivyside Dr., Altoona, PA 16601, USA
| | - Tracy Langkilde
- Eberly College of Science, Pennsylvania State University, University Park, PA 16802, USA
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11
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Casagrande S, Loveland JL, Oefele M, Boner W, Lupi S, Stier A, Hau M. Dietary nucleotides can prevent glucocorticoid-induced telomere attrition in a fast-growing wild vertebrate. Mol Ecol 2023; 32:5429-5447. [PMID: 37658759 DOI: 10.1111/mec.17114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/20/2023] [Accepted: 08/09/2023] [Indexed: 09/05/2023]
Abstract
Telomeres are chromosome protectors that shorten during eukaryotic cell replication and in stressful conditions. Developing individuals are susceptible to telomere erosion when their growth is fast and resources are limited. This is critical because the rate of telomere attrition in early life is linked to health and life span of adults. The metabolic telomere attrition hypothesis (MeTA) suggests that telomere dynamics can respond to biochemical signals conveying information about the organism's energetic state. Among these signals are glucocorticoids, hormones that promote catabolic processes, potentially impairing costly telomere maintenance, and nucleotides, which activate anabolic pathways through the cellular enzyme target of rapamycin (TOR), thus preventing telomere attrition. During the energetically demanding growth phase, the regulation of telomeres in response to two contrasting signals - one promoting telomere maintenance and the other attrition - provides an ideal experimental setting to test the MeTA. We studied nestlings of a rapidly developing free-living passerine, the great tit (Parus major), that either received glucocorticoids (Cort-chicks), nucleotides (Nuc-chicks) or a combination of both (NucCort-chicks), comparing these with controls (Cnt-chicks). As expected, Cort-chicks showed telomere attrition, while NucCort- and Nuc-chicks did not. NucCort-chicks was the only group showing increased expression of a proxy for TOR activation (the gene TELO2), of mitochondrial enzymes linked to ATP production (cytochrome oxidase and ATP-synthase) and a higher efficiency in aerobically producing ATP. NucCort-chicks had also a higher expression of telomere maintenance genes (shelterin protein TERF2 and telomerase TERT) and of enzymatic antioxidant genes (glutathione peroxidase and superoxide dismutase). The findings show that nucleotide availability is crucial for preventing telomere erosion during fast growth in stressful environments.
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Affiliation(s)
- Stefania Casagrande
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
| | - Jasmine L Loveland
- Department of Cognitive and Behavioral Biology, University of Vienna, Vienna, Austria
| | - Marlene Oefele
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
| | - Winnie Boner
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Sara Lupi
- Konrad Lorenz Institute of Ethology, Vienna, Austria
| | - Antoine Stier
- Université de Strasbourg, CNRS, Institut Pluridisciplinaire Hubert Curien, UMR7178, Strasbourg, France
- Department of Biology, University of Turku, Turku, Finland
| | - Michaela Hau
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
- Department of Biology, University of Konstanz, Constance, Germany
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12
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Mutwill AM, Schielzeth H, Richter SH, Kaiser S, Sachser N. Conditional on the social environment? Roots of repeatability in hormone concentrations of male guinea pigs. Horm Behav 2023; 155:105423. [PMID: 37713739 DOI: 10.1016/j.yhbeh.2023.105423] [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: 06/24/2023] [Revised: 08/20/2023] [Accepted: 08/23/2023] [Indexed: 09/17/2023]
Abstract
Individual differences in behavioral and physiological traits among members of the same species are increasingly being recognized as important in animal research. On the group level, shaping of behavioral and hormonal phenotypes by environmental factors has been reported in different taxa. The extent to which the environment impacts behavior and hormones on the individual level, however, is rather unexplored. Hormonal phenotypes of guinea pigs can be shaped by the social environment on the group level: pair-housed and colony-housed males differ systematically in average testosterone and stressor-induced cortisol levels (i.e. cortisol responsiveness). The aim of the present study was to evaluate whether repeatability and individual variance components (i.e. between- and within-individual variation) of hormonal phenotypes also differ in different social environments. To test this, we determined baseline testosterone, baseline cortisol, and cortisol responsiveness after challenge in same-aged pair-housed and colony-housed guinea pig males over a period of four months. We found comparable repeatability for baseline cortisol and cortisol responsiveness in males from both social conditions. In contrast, baseline testosterone was repeatable only in males from colonies. Interestingly, this result was brought about by significantly larger between-individual variation of testosterone, that was not explained by differences in dominance rank. Individualized social niches differentiated under complex colony, but not pair housing, could be an explanation for this finding.
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Affiliation(s)
- Alexandra M Mutwill
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany.
| | - Holger Schielzeth
- Population Ecology Group, Institute of Ecology, Friedrich Schiller University, Dornburgerstr. 159, 07743 Jena, Germany
| | - S Helene Richter
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany
| | - Sylvia Kaiser
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany
| | - Norbert Sachser
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany
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13
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MacLeod KJ, English S, Ruuskanen SK, Taborsky B. Stress in the social context: a behavioural and eco-evolutionary perspective. J Exp Biol 2023; 226:jeb245829. [PMID: 37529973 PMCID: PMC10445731 DOI: 10.1242/jeb.245829] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
The social environment is one of the primary sources of challenging stimuli that can induce a stress response in animals. It comprises both short-term and stable interactions among conspecifics (including unrelated individuals, mates, potential mates and kin). Social stress is of unique interest in the field of stress research because (1) the social domain is arguably the most complex and fluctuating component of an animal's environment; (2) stress is socially transmissible; and (3) stress can be buffered by social partners. Thus, social interactions can be both the cause and cure of stress. Here, we review the history of social stress research, and discuss social stressors and their effects on organisms across early life and adulthood. We also consider cross-generational effects. We discuss the physiological mechanisms underpinning social stressors and stress responses, as well as the potential adaptive value of responses to social stressors. Finally, we identify outstanding challenges in social stress research, and propose a framework for addressing these in future work.
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Affiliation(s)
| | - Sinead English
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Suvi K. Ruuskanen
- Department of Biological and Environmental Science, University of Jyväskylä, Survontie 9 C, FI-40014, Finland
- Department of Biology, University of Turku, Turku, FI-20014, Finland
| | - Barbara Taborsky
- Division of Behavioural Biology, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Institute for Advanced Study, 14193 Berlin, Germany
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14
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Radley JJ, Herman JP. Preclinical Models of Chronic Stress: Adaptation or Pathology? Biol Psychiatry 2023; 94:194-202. [PMID: 36631383 PMCID: PMC10166771 DOI: 10.1016/j.biopsych.2022.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 10/15/2022] [Accepted: 11/02/2022] [Indexed: 11/11/2022]
Abstract
The experience of prolonged stress changes how individuals interact with their environment and process interoceptive cues, with the end goal of optimizing survival and well-being in the face of a now-hostile world. The chronic stress response includes numerous changes consistent with limiting further damage to the organism, including development of passive or active behavioral strategies and metabolic adjustments to alter energy mobilization. These changes are consistent with symptoms of pathology in humans, and as a result, chronic stress has been used as a translational model for diseases such as depression. While it is of heuristic value to understand symptoms of pathology, we argue that the chronic stress response represents a defense mechanism that is, at its core, adaptive in nature. Transition to pathology occurs only after the adaptive capacity of an organism is exhausted. We offer this perspective as a means of framing interpretations of chronic stress studies in animal models and how these data relate to adaptation as opposed to pathology.
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Affiliation(s)
- Jason J Radley
- Department of Psychological and Brain Sciences, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa
| | - James P Herman
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio; Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio.
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15
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Dantzer B. Frank Beach Award Winner: The centrality of the hypothalamic-pituitary-adrenal axis in dealing with environmental change across temporal scales. Horm Behav 2023; 150:105311. [PMID: 36707334 DOI: 10.1016/j.yhbeh.2023.105311] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 01/02/2023] [Accepted: 01/06/2023] [Indexed: 01/26/2023]
Abstract
Understanding if and how individuals and populations cope with environmental change is an enduring question in evolutionary ecology that has renewed importance given the pace of change in the Anthropocene. Two evolutionary strategies of coping with environmental change may be particularly important in rapidly changing environments: adaptive phenotypic plasticity and/or bet hedging. Adaptive plasticity could enable individuals to match their phenotypes to the expected environment if there is an accurate cue predicting the selective environment. Diversifying bet hedging involves the production of seemingly random phenotypes in an unpredictable environment, some of which may be adaptive. Here, I review the central role of the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoids (GCs) in enabling vertebrates to cope with environmental change through adaptive plasticity and bet hedging. I first describe how the HPA axis mediates three types of adaptive plasticity to cope with environmental change (evasion, tolerance, recovery) over short timescales (e.g., 1-3 generations) before discussing how the implications of GCs on phenotype integration may depend upon the timescale under consideration. GCs can promote adaptive phenotypic integration, but their effects on phenotypic co-variation could also limit the dimensions of phenotypic space explored by animals over longer timescales. Finally, I discuss how organismal responses to environmental stressors can act as a bet hedging mechanism and therefore enhance evolvability by increasing genetic or phenotypic variability or reducing patterns of genetic and phenotypic co-variance. Together, this emphasizes the crucial role of the HPA axis in understanding fundamental questions in evolutionary ecology.
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Affiliation(s)
- Ben Dantzer
- Department of Psychology, University of Michigan, MI 48109 Ann Arbor, MI, USA; Department of Ecology and Evolutionary Biology, University of Michigan, MI 48109, Ann Arbor, MI, USA.
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16
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Ruiz-Raya F, Noguera JC, Velando A. Covariation between glucocorticoid levels and receptor expression modulates embryo development and postnatal phenotypes in gulls. Horm Behav 2023; 149:105316. [PMID: 36731260 DOI: 10.1016/j.yhbeh.2023.105316] [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: 06/21/2022] [Revised: 12/21/2022] [Accepted: 01/17/2023] [Indexed: 02/01/2023]
Abstract
The hypothalamic-pituitary-adrenocortical axis can translate, through glucocorticoid secretion, the prenatal environment to development to produce phenotypes that match prevailing environmental conditions. However, whether developmental plasticity is modulated by the interaction between circulating glucocorticoids and receptor expression remains unclear. Here, we tested whether covariation between plasma corticosterone (CORT) and glucocorticoid receptor gene (Nr3c1) expression in blood underlies embryonic developmental programming in yellow-legged gulls (Larus michahellis). We examined variations in circulating levels of CORT and the expression and DNA methylation patterns of Nr3c1 in response to two ecologically relevant prenatal factors: adult alarm calls (a cue of predator presence) and changes in prenatal light environment (a cue of competitive disadvantage). We then determined whether embryonic development and postnatal phenotypes were associated with CORT levels and Nr3c1 expression, and explored direct and indirect relationships between the prenatal environment, hormone-receptor covariation, and postnatal phenotypes. Prenatal exposure to alarm calls increased CORT levels and up-regulated Nr3c1 expression in gull chicks, while exposure to light cues reduced both hormone levels and receptor expression. Chicks prenatally exposed to alarm calls showed altered DNA methylation profiles in the Nr3c1 regulatory region, but patterns varied throughout the breeding season and between years. Moreover, our results suggest a negative relationship between DNA methylation and expression in Nr3c1 , at least at specific CpG sites. The interplay between circulating CORT and Nr3c1 expression affected embryo developmental timing and vocalizations, as well as hatchling mass and fitness-relevant behaviours. These findings provide a link between prenatal inputs, glucocorticoid function and phenotypic outcomes, suggesting that hormone-receptor interaction may underlie developmental programming in free-living animals.
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Affiliation(s)
- Francisco Ruiz-Raya
- Centro de Investigación Mariña, Universidade de Vigo, Grupo de Ecoloxía Animal, Vigo 36310, Spain.
| | - Jose C Noguera
- Centro de Investigación Mariña, Universidade de Vigo, Grupo de Ecoloxía Animal, Vigo 36310, Spain
| | - Alberto Velando
- Centro de Investigación Mariña, Universidade de Vigo, Grupo de Ecoloxía Animal, Vigo 36310, Spain
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17
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Heppner JJ, Krause JS, Ouyang JQ. Urbanization and maternal hormone transfer: Endocrine and morphological phenotypes across ontogenetic stages. Gen Comp Endocrinol 2023; 333:114166. [PMID: 36402244 DOI: 10.1016/j.ygcen.2022.114166] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/11/2022] [Accepted: 11/12/2022] [Indexed: 11/18/2022]
Abstract
The phenotypes observed in urban and rural environments are often distinct; however, it remains unclear how these novel urban phenotypes arise. Hormone-mediated maternal effects likely play a key role in shaping developmental trajectories of offspring in different environments. Thus, we measured corticosterone (Cort) and testosterone (T) concentrations in eggs across the laying sequence in addition to Cort concentrations in nestling and adult female house wrens (Troglodytes aedon) at one urban and one rural site. We found that egg T concentrations were not different between birds from urban and rural sites. However, across all life stages (egg, nestling, and adult female), Cort concentrations were higher at the urban site. Additionally, urban nestling Cort concentrations, but not rural, correlated with fine-scale urban density scores. Furthermore, rural egg volume increased over the laying sequence, but urban egg volume leveled off mid-sequence, suggesting either that urban mothers are resource limited or that they are employing a different brood development strategy than rural mothers. Our study is one of the first to show that egg hormone concentrations differ in an urban environment with differences persisting in chick development and adult life stages. We suggest that maternal endocrine programing may shape offspring phenotypes in urban environments and are an overlooked yet important aspect underlying mechanisms of urban evolution.
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Affiliation(s)
| | - Jesse S Krause
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Jenny Q Ouyang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
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18
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Monroe DJ, Barny LA, Wu A, Minbiole KPC, Gabor CR. An integrated physiological perspective on anthropogenic stressors in the Gulf coast toad (Incilius nebulifer). Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1112982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Anthropogenic environmental change, including climate change and urbanization, results in warmer temperatures in both terrestrial and aquatic habitats and changes in community assemblages including invasive species introductions, among many other alterations. Anurans are particularly susceptible to these changes because generally they have a biphasic lifecycle and rely on aquatic and terrestrial habitats for survival. Changes such as warmer water temperature can result in direct and carryover effects, after metamorphosis that decrease fitness. However, Gulf Coast toads (Incilius (Bufo) nebulifer) are expanding their range, including into anthropogenically disturbed areas. We hypothesize that I. nebulifer copes with warmer water, reduced water levels, and invasive species by altering their physiology and/or behavior. Corticosterone is the primary glucocorticoid in amphibians, and it modulates many aspects of physiology and behavior, potentially including lipid storage and hop performance, during unpredictable (stressful) events. As a true toad, I. nebulifer also produces bufadienolide toxins that aid in its antipredator defense and may have tradeoffs with corticosterone. In a fully factorial design, we measured baseline corticosterone levels in tadpoles in response to two treatments: decreased water levels and increased water temperatures. After metamorphosis, we measured the corticosterone profile and other associated responses to exposure to the predatory red imported fire ant (Solenopsis invicta; RIFA). We found that tadpoles had elevated baseline corticosterone release rates when reared in warmer water and reduced water levels. Toadlets also had elevated baseline corticosterone release rates when exposed to any combination of two of the three treatments but when exposed to all three treatments toadlets instead showed elevated magnitude of their stress response. Predator avoidance (as measured by hop performance) was reduced after exposure to RIFA. Tadpoles from warmer water developed more quickly and were smaller in mass after metamorphosis. Toadlets had reduced production of two of the three detected bufadienolides and increased energy storage (lipids) after exposure to warmer water and reduced growth after exposure to reduced water levels. We found direct and carryover effects of common anthropogenic changes in I. nebulifer that may aid in their ability to persist despite these changes.
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19
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Palacios MG, Bronikowski AM, Amer A, Gangloff EJ. Transgenerational effects of maternal corticosterone across early life in a viviparous snake. Gen Comp Endocrinol 2023; 331:114162. [PMID: 36356645 DOI: 10.1016/j.ygcen.2022.114162] [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: 08/19/2022] [Revised: 10/28/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022]
Abstract
Glucocorticoids (GCs) are central mediators of vertebrate responses to intrinsic and extrinsic stimuli. Among the sources of variation in circulating GCs are transgenerational effects mediated by mothers. Here we studied potential maternal effects mediated by GCs on offspring phenotype in a live-bearing reptile, the western terrestrial garter snake (Thamnophis elegans). We evaluated the association between baseline corticosterone (CORT) levels during gestation (i.e., preparturition) in field-captured mothers and 1) reproductive success and offspring sex ratios, 2) birth phenotypic traits of offspring born under common-garden laboratory conditions, and 3) neonate (age 3 months) and juvenile (age 12 months) traits of offspring raised under two thermal regimes ('warm' and 'cool') during their first year of life. Reproductive success and offspring sex ratios were not associated with preparturition maternal CORT, but pregnant snakes with higher CORT levels gave birth to smaller, lighter offspring, which tended to grow faster to age three months. Neonate baseline CORT varied with preparturition maternal CORT in a sex-specific manner (positive trend for females, negative for males). Maternal CORT effects on offspring phenotype were no longer detectable in juveniles at age one year. Instead, juvenile phenotypes were most influenced by rearing environment, with offspring raised under the cool regime showing higher baseline CORT and slower growth than those raised under warmer conditions. Our findings support the notion that offspring phenotype might be continuously adjusted in response to environmental cues -both pre- and post-natal- and that the strength of maternal CORT effects declines as offspring develop and experience unique environmental challenges. Our results contribute to a growing literature on transgenerational effects of hormones and help to fill a gap in our knowledge of these effects in ectothermic amniotes.
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Affiliation(s)
- Maria G Palacios
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA; Centro Para el Estudio de Sistemas Marinos, CCT CONICET-CENPAT, Blvd. Brown 2915, Puerto Madryn, Chubut, Argentina.
| | - Anne M Bronikowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA; Kellogg Biological Station, Michigan State University, Hickory Corners, MI, USA
| | - Ali Amer
- Department of Biological Sciences, Ohio Wesleyan University, Delaware, OH, USA
| | - Eric J Gangloff
- Department of Biological Sciences, Ohio Wesleyan University, Delaware, OH, USA
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20
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Zimmer C, Taff CC, Ardia DR, Rosvall KA, Kallenberg C, Bentz AB, Taylor AR, Johnson LS, Vitousek MN. Gene expression in the female tree swallow brain is associated with inter- and intra-population variation in glucocorticoid levels. Horm Behav 2023; 147:105280. [PMID: 36403365 DOI: 10.1016/j.yhbeh.2022.105280] [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: 02/06/2022] [Revised: 10/12/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022]
Abstract
Studies of the evolutionary causes and consequences of variation in circulating glucocorticoids (GCs) have begun to reveal how they are shaped by selection. Yet the extent to which variation in circulating hormones reflects variation in other important regulators of the hypothalamic-pituitary-adrenal (HPA) axis, and whether these relationships vary among populations inhabiting different environments, remain poorly studied. Here, we compare gene expression in the brain of female tree swallows (Tachycineta bicolor) from populations that breed in environments that differ in their unpredictability. We find evidence of inter-population variation in the expression of glucocorticoid and mineralocorticoid receptors in the hypothalamus, with the highest gene expression in a population from an extreme environment, and lower expression in a population from a more consistent environment as well as in birds breeding at an environmentally variable high-altitude site that are part of a population that inhabits a mixture of high and low altitude habitats. Within some populations, variation in circulating GCs predicted differences in gene expression, particularly in the hypothalamus. However, some patterns were present in all populations, whereas others were not. These results are consistent with the idea that some combination of local adaptation and phenotypic plasticity may modify components of the HPA axis affecting stress resilience. Our results also underscore that a comprehensive understanding of the function and evolution of the stress response cannot be gained from measuring circulating hormones alone, and that future studies that apply a more explicitly evolutionary approach to important regulatory traits are likely to provide significant insights.
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Affiliation(s)
- Cedric Zimmer
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA; Laboratoire d'Ethologie Expérimentale et Comparée, LEEC, Université Sorbonne Paris Nord, UR 4443, 93430 Villetaneuse, France.
| | - Conor C Taff
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA; Cornell Lab of Ornithology, Ithaca, NY 14850, USA
| | - Daniel R Ardia
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17604, USA
| | - Kimberly A Rosvall
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Christine Kallenberg
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Alexandra B Bentz
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA; Department of Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Audrey R Taylor
- Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - L Scott Johnson
- Department of Biological Sciences, Towson University, Towson, MD 21252, USA
| | - Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA; Cornell Lab of Ornithology, Ithaca, NY 14850, USA
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21
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Carbillet J, Hollain M, Rey B, Palme R, Pellerin M, Regis C, Geffré A, Duhayer J, Pardonnet S, Debias F, Merlet J, Lemaître JF, Verheyden H, Gilot-Fromont E. Age and spatio-temporal variations in food resources modulate stress-immunity relationships in three populations of wild roe deer. Gen Comp Endocrinol 2023; 330:114141. [PMID: 36272446 DOI: 10.1016/j.ygcen.2022.114141] [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: 03/08/2022] [Revised: 10/07/2022] [Accepted: 10/09/2022] [Indexed: 11/17/2022]
Abstract
Living in variable and unpredictable environments, organisms face recurrent stressful situations. The endocrine stress response, which includes the secretion of glucocorticoids, helps organisms to cope with these perturbations. Although short-term elevations of glucocorticoid levels are often associated with immediate beneficial consequences for individuals, long-term glucocorticoid elevation can compromise key physiological functions such as immunity. While laboratory works highlighted the immunosuppressive effect of long-term elevated glucocorticoids, it remains largely unknown, especially in wild animals, whether this relationship is modulated by individual and environmental characteristics. In this study, we explored the co-variation between integrated cortisol levels, assessed non-invasively using faecal cortisol metabolites (FCMs), and 12 constitutive indices of innate, inflammatory, and adaptive immune functions, in wild roe deer living in three populations with previously known contrasting environmental conditions. Using longitudinal data on 564 individuals, we further investigated whether age and spatio-temporal variations in the quantity and quality of food resources modulate the relationship between FCMs and immunity. Negative covariation with glucocorticoids was evident only for innate and inflammatory markers of immunity, while adaptive immunity appeared to be positively or not linked to glucocorticoids. In addition, the negative covariations were generally stronger in individuals facing harsh environmental constraints and in old individuals. Therefore, our results highlight the importance of measuring multiple immune markers of immunity in individuals from contrasted environments to unravel the complex relationships between glucocorticoids and immunity in wild animals. Our results also help explain conflicting results found in the literature and could improve our understanding of the link between elevated glucocorticoid levels and disease spread, and its consequences on population dynamics.
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Affiliation(s)
- Jeffrey Carbillet
- Université de Toulouse, INRAE, CEFS, Castanet Tolosan, 31326, France; LTSER ZA PYRénées GARonne, Auzeville-Tolosane, 31320, France; Université de Lyon, VetAgro Sup, Marcy-l'Etoile, 69280, France; Institute of Ecology and Earth Sciences, University of Tartu, Tartu 51014, Estonia.
| | - Marine Hollain
- Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex 69100, France; Office Français de la biodiversité, Direction de la Recherche et de l'Appui Scientifique, Service Conservation et Gestion Durable des Espèces Exploitées, Chateauvillain 52210, France
| | - Benjamin Rey
- Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex 69100, France
| | - Rupert Palme
- Unit of Physiology, Pathophysiology, and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna 1210, Austria
| | - Maryline Pellerin
- Office Français de la biodiversité, Direction de la Recherche et de l'Appui Scientifique, Service Conservation et Gestion Durable des Espèces Exploitées, Chateauvillain 52210, France
| | - Corinne Regis
- Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex 69100, France
| | - Anne Geffré
- Equipe de Biologie médicale-Histologie, CREFRE, Inserm-UPS-ENVT, Toulouse 31000, France
| | - Jeanne Duhayer
- Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex 69100, France
| | - Sylvia Pardonnet
- Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex 69100, France
| | - François Debias
- Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex 69100, France
| | - Joël Merlet
- Université de Toulouse, INRAE, CEFS, Castanet Tolosan, 31326, France; LTSER ZA PYRénées GARonne, Auzeville-Tolosane, 31320, France
| | | | - Hélène Verheyden
- Université de Toulouse, INRAE, CEFS, Castanet Tolosan, 31326, France; LTSER ZA PYRénées GARonne, Auzeville-Tolosane, 31320, France
| | - Emmanuelle Gilot-Fromont
- Université de Lyon, VetAgro Sup, Marcy-l'Etoile, 69280, France; Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex 69100, France
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22
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Gilmour KM, Bard B. Social buffering of the stress response: insights from fishes. Biol Lett 2022; 18:20220332. [PMID: 36285460 PMCID: PMC9597401 DOI: 10.1098/rsbl.2022.0332] [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: 11/12/2022] Open
Abstract
Social buffering of stress refers to the effect of a social partner in reducing the cortisol or corticosterone response to a stressor. It has been well studied in mammals, particularly those that form pair bonds. Recent studies on fishes suggest that social buffering of stress also occurs in solitary species, gregarious species that form loose aggregations and species with well-defined social structures and bonds. The diversity of social contexts in which stress buffering has been observed in fishes holds promise to shed light on the evolution of this phenomenon among vertebrates. Equally, the relative simplicity of the fish brain is advantageous for identifying the neural mechanisms responsible for social buffering. In particular, fishes have a relatively small and simple forebrain but the brain regions that are key to social buffering, including the social behaviour network, the amygdala and the hypothalamic-pituitary-adrenal/interrenal axis, are functionally conserved across vertebrates. Thus, we suggest that insight into the mechanistic and evolutionary underpinnings of stress buffering in vertebrates can be gained from the study of social buffering of stress in fishes.
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Affiliation(s)
- Kathleen M. Gilmour
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5
| | - Brittany Bard
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5
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23
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Santicchia F, Wauters LA, Dantzer B, Palme R, Tranquillo C, Preatoni D, Martinoli A. Native species exhibit physiological habituation to invaders: a reason for hope. Proc Biol Sci 2022; 289:20221022. [PMID: 36168765 PMCID: PMC9515632 DOI: 10.1098/rspb.2022.1022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/05/2022] [Indexed: 11/12/2022] Open
Abstract
Animals cope with environmental perturbations through the stress response, a set of behavioural and physiological responses aimed to maintain and/or return to homeostasis and enhance fitness. Vertebrate neuroendocrine axis activation in response to environmental stressors can result in the secretion of glucocorticoids (GCs), whose acute increases may be adaptive, while chronic elevation may be detrimental. Invasive grey squirrels (Sciurus carolinensis) act as a stressor eliciting elevation of GCs in native red squirrels (Sciurus vulgaris). Here we used 6-year data of variation in faecal glucocorticoid metabolite (FGM) concentrations following invasion by grey squirrels in three red squirrel populations, to identify if red squirrels showed physiological habituation to this stressor. The decrease in FGMs over time was more pronounced shortly after invasion and at high densities of grey squirrels while it decreased less strongly and was no longer influenced by the invader density as time since invasion elapsed. At the individual level, FGMs also decreased more markedly as each red squirrel experienced prolonged contact with the invader. Our study provides compelling new data suggesting that native species in the wild can habituate to prolonged contact with invasive species, showing that they may avoid the potentially harmful effects of chronic elevations in GCs.
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Affiliation(s)
- Francesca Santicchia
- Environment Analysis and Management Unit - Guido Tosi Research Group - Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Lucas Armand Wauters
- Environment Analysis and Management Unit - Guido Tosi Research Group - Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Campus Drie Eiken Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Ben Dantzer
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI, 48109, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Claudia Tranquillo
- Environment Analysis and Management Unit - Guido Tosi Research Group - Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Damiano Preatoni
- Environment Analysis and Management Unit - Guido Tosi Research Group - Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Adriano Martinoli
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Campus Drie Eiken Universiteitsplein 1, 2610 Wilrijk, Belgium
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24
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Taff C. Simulating physiological flexibility in the acute glucocorticoid response to stressors reveals limitations of current empirical approaches. PeerJ 2022; 10:e14039. [PMID: 36132217 PMCID: PMC9484456 DOI: 10.7717/peerj.14039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 08/19/2022] [Indexed: 01/19/2023] Open
Abstract
Wild animals often experience unpredictable challenges that demand rapid and flexible responses. The glucocorticoid mediated stress response is one of the major systems that allows vertebrates to rapidly adjust their physiology and behavior. Given its role in responding to challenges, evolutionary physiologists have focused on the consequences of between-individual and, more recently, within-individual variation in the acute glucocorticoid response. However, empirical studies of physiological flexibility are severely limited by the logistical challenges of measuring the same animal multiple times. Data simulation is a powerful approach when empirical data are limited, but has not been adopted to date in studies of physiological flexibility. In this article, I develop a simulation that can generate realistic acute glucocorticoid response data with user specified characteristics. Simulated animals can be sampled continuously through an acute response and across as many separate responses as desired, while varying key parameters. Using the simulation, I develop several scenarios that address key questions in physiological flexibility. These scenarios demonstrate the conditions under which a single glucocorticoid trait can be accurately assessed with typical experimental designs, the consequences of covariation between different components of the acute stress response, and the way that context specific differences in variability of acute responses can influence the power to detect relationships between the strength of the acute stress response and fitness. I also describe how to use the simulation tools to aid in the design and evaluation of empirical studies of physiological flexibility.
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Affiliation(s)
- Conor Taff
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States,Lab of Ornithology, Cornell University, Ithaca, NY, United States
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25
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Martin LB, Zimmer C. Endocrine flexibility. J Exp Biol 2022; 225:276445. [PMID: 36017760 DOI: 10.1242/jeb.244646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/13/2022] [Indexed: 11/20/2022]
Affiliation(s)
- Lynn B Martin
- University of South Florida, Center for Global Health and Infectious Disease Research and Center for Genomics, Tampa, FL 33612, USA
| | - Cedric Zimmer
- Laboratoire d'Ethologie Expérimentale et Comparée, LEEC, Université Sorbonne Paris Nord, UR 4443, 93430 Villetaneuse, France
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26
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Taff CC, Wingfield JC, Vitousek MN. The relative speed of the glucocorticoid stress response varies independently of scope and is predicted by environmental variability and longevity across birds. Horm Behav 2022; 144:105226. [PMID: 35863083 DOI: 10.1016/j.yhbeh.2022.105226] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 01/27/2023]
Abstract
The acute glucocorticoid response is a key mediator of the coordinated vertebrate response to unpredictable challenges. Rapid glucocorticoid increases initiate changes that allow animals to cope with stressors. The scope of the glucocorticoid response - defined here as the absolute increase in glucocorticoids - is associated with individual differences in performance and varies across species with environment and life history. In addition to varying in scope, responses can differ enormously in speed; however, relatively little is known about whether speed and absolute glucocorticoid levels covary, how selection shapes speed, or what aspects of speed are important. We used corticosterone samples collected at 5 time points from 1750 individuals of 60 species of birds to ask i) how the speed and scope of the glucocorticoid response covary and ii) whether variation in absolute or relative speed is predicted by environmental context or life history. Among species, faster absolute glucocorticoid responses were strongly associated with a larger scope. Despite this covariation, the relative speed of the glucocorticoid response (standardized within species) varied independently of absolute scope, suggesting that selection could operate on both features independently. Species with faster relative glucocorticoid responses lived in locations with more variable temperature and had shorter lifespans. Our results suggest that rapid changes associated with the speed of the glucocorticoid response, such as those occurring through non-genomic receptors, might be an important determinant of coping ability and we emphasize the need for studies designed to measure speed independently of absolute glucocorticoid levels.
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Affiliation(s)
- Conor C Taff
- Department of Ecology & Evolutionary Biology and Lab of Ornithology, Cornell University, United States of America.
| | - John C Wingfield
- Department of Neurobiology, Physiology, and Behavior, University of California-Davis, United States of America
| | - Maren N Vitousek
- Department of Ecology & Evolutionary Biology and Lab of Ornithology, Cornell University, United States of America
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27
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Ruthsatz K, Bartels F, Stützer D, Eterovick PC. Timing of parental breeding shapes sensitivity to nitrate pollution in the common frog Rana temporaria. J Therm Biol 2022; 108:103296. [DOI: 10.1016/j.jtherbio.2022.103296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 06/09/2022] [Accepted: 07/19/2022] [Indexed: 11/28/2022]
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28
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Luttbeg B, Grindstaff JL. Optimal hormonal regulation when stressor cues are imperfect. Horm Behav 2022; 144:105227. [PMID: 35780563 PMCID: PMC10153792 DOI: 10.1016/j.yhbeh.2022.105227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 11/04/2022]
Abstract
The endocrine system uses information about the environment and the individual's state to regulate circulating concentrations of hormones, and then those hormones, through receptor binding, cause changes in the phenotype. How quickly individuals can up- and down-regulate their hormones can affect baseline and elevated hormone levels and presumably affects how successfully individuals can cope with a varying environment. To respond to environmental change, individuals first need to perceive and process cues about the state of the environment. Individuals may receive imperfect cues about the environment due to perceptual errors, variation in cues, or inexperience with novel stressors. In this paper we use a mathematical model to ask how these imperfect cues should affect how individuals regulate their glucocorticoid concentrations. We find imperfect cues can lead to changes in hormone regulation with individuals generally having higher baseline and lower elevated hormone levels as environmental cues become less reliable. Informational constraints and physiological constraints appear to have generally additive effects, with informational constraints having less of an impact as physiological constraints increase. Our results highlight the different means by which imperfect information can affect hormone regulation. We find that mistakes caused by imperfect cues are commonly responsible for changes in average hormone levels, but imperfect cues also cause individuals to be slower and less certain in their updated estimates of the environmental state, which affects hormone regulation. We also demonstrate the separate effects of false positive and false negative cues and how these are shaped by the relative fitness consequences of baseline and stress-induced hormone levels. Our model shows how given our assumptions imperfect stressor cues should affect endocrine flexibility and regulation, and we hope provides a piece for future conversations and models of endocrine regulation.
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Affiliation(s)
- Barney Luttbeg
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, United States.
| | - Jennifer L Grindstaff
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, United States.
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29
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Dantzer B, Newman AEM. Expanding the frame around social dynamics and glucocorticoids: From hierarchies within the nest to competitive interactions among species. Horm Behav 2022; 144:105204. [PMID: 35689971 DOI: 10.1016/j.yhbeh.2022.105204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/10/2022] [Accepted: 05/18/2022] [Indexed: 11/25/2022]
Abstract
The effect of the social environment on individual state or condition has largely focused on glucocorticoid levels (GCs). As metabolic hormones whose production can be influenced by nutritional, physical, or psychosocial stressors, GCs are a valuable (though singular) measure that may reflect the degree of "stress" experienced by an individual. Most work to date has focused on how social rank influences GCs in group-living species or how predation risk influences GCs in prey. This work has been revealing, but a more comprehensive assessment of the social environment is needed to fully understand how different features of the social environment influence GCs in both group living and non-group living species and across life history stages. Just as there can be intense within-group competition among adult conspecifics, it bears appreciating there can also be competition among siblings from the same brood, among adult conspecifics that do not live in groups, or among heterospecifics. In these situations, dominance hierarchies typically emerge, albeit, do dominants or subordinate individuals or species have higher GCs? We examine the degree of support for hypotheses derived from group-living species about whether differential GCs between dominants and subordinates reflect the "stress of subordination" or "costs of dominance" in these other social contexts. By doing so, we aim to test the generality of these two hypotheses and propose new research directions to broaden the lens that focuses on social hierarchies and GCs.
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Affiliation(s)
- Ben Dantzer
- Department of Psychology, University of Michigan, 48109 Ann Arbor, MI, USA; Department of Ecology and Evolutionary Biology, University of Michigan, 48109, Ann Arbor, MI, USA.
| | - Amy E M Newman
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G2W1, Canada
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30
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Matzke CC, Kusch JM, Janz DM, Lane JE. Perceived predation risk predicts glucocorticoid hormones, but not reproductive success in a colonial rodent. Horm Behav 2022; 143:105200. [PMID: 35617896 DOI: 10.1016/j.yhbeh.2022.105200] [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: 10/29/2021] [Revised: 05/09/2022] [Accepted: 05/11/2022] [Indexed: 11/29/2022]
Abstract
The Cort-Adaptation hypothesis suggests that elevated glucocorticoids (GCs) can facilitate an adaptive response to environmental and physiological challenges. Most previous studies have focused on avian species, which may limit their generalizability to mammals, where lactation is known to be a major physiological challenge. Furthermore, the effect of predation risk on GC levels has not been tested in the Cort-Adaptation hypothesis. We sought to test this hypothesis in a colonial prey species, black-tailed prairie dogs (Cynomys ludovicianus). We predicted that individuals located near fewer neighboring conspecifics would perceive an increased risk of predation and, in turn, have increased GCs (measured through hair cortisol concentration (HCC)) and reduced annual reproductive success compared to more centrally located individuals. We also investigated other putative influences on HCC: age, lactation status, body condition, and season of hair growth. Levels of vigilance behavior were higher for those with fewer neighboring conspecifics, suggesting variation in perceived risk of predation. Further, the risk of predation appeared to represent a chronic, detrimental stressor as evidenced by a significant increase in HCC for prairie dogs with fewer neighbors. Lactation status and season also influenced HCC. We found support for the Cort-Adaptation hypothesis where increased HCC during the reproductive season correlated with whether a female produced a litter, but not litter size, suggesting a minimum threshold of GCs is required for successful reproduction in this species. Our work illustrates that HCC may operate as an indicator of perceived predation risk, but care should be taken to consider the variety of factors influencing GC homeostasis, in particular lactation, when drawing conclusions using HCC as a marker of long-term stress.
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Affiliation(s)
| | - Jillian M Kusch
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - David M Janz
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
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31
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Taborsky B, Kuijper B, Fawcett TW, English S, Leimar O, McNamara JM, Ruuskanen S. An evolutionary perspective on stress responses, damage and repair. Horm Behav 2022; 142:105180. [PMID: 35569424 DOI: 10.1016/j.yhbeh.2022.105180] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/16/2022] [Accepted: 04/21/2022] [Indexed: 11/28/2022]
Abstract
Variation in stress responses has been investigated in relation to environmental factors, species ecology, life history and fitness. Moreover, mechanistic studies have unravelled molecular mechanisms of how acute and chronic stress responses cause physiological impacts ('damage'), and how this damage can be repaired. However, it is not yet understood how the fitness effects of damage and repair influence stress response evolution. Here we study the evolution of hormone levels as a function of stressor occurrence, damage and the efficiency of repair. We hypothesise that the evolution of stress responses depends on the fitness consequences of damage and the ability to repair that damage. To obtain some general insights, we model a simplified scenario in which an organism repeatedly encounters a stressor with a certain frequency and predictability (temporal autocorrelation). The organism can defend itself by mounting a stress response (elevated hormone level), but this causes damage that takes time to repair. We identify optimal strategies in this scenario and then investigate how those strategies respond to acute and chronic exposures to the stressor. We find that for higher repair rates, baseline and peak hormone levels are higher. This typically means that the organism experiences higher levels of damage, which it can afford because that damage is repaired more quickly, but for very high repair rates the damage does not build up. With increasing predictability of the stressor, stress responses are sustained for longer, because the animal expects the stressor to persist, and thus damage builds up. This can result in very high (and potentially fatal) levels of damage when organisms are exposed to chronic stressors to which they are not evolutionarily adapted. Overall, our results highlight that at least three factors need to be considered jointly to advance our understanding of how stress physiology has evolved: (i) temporal dynamics of stressor occurrence; (ii) relative mortality risk imposed by the stressor itself versus damage caused by the stress response; and (iii) the efficiency of repair mechanisms.
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Affiliation(s)
- Barbara Taborsky
- Behavioural Ecology Division, Institute of Ecology and Evolution, University of Bern, Switzerland.
| | - Bram Kuijper
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, UK; Institute for Data Science and Artificial Intelligence, University of Exeter, UK
| | - Tim W Fawcett
- Centre for Research in Animal Behaviour (CRAB), University of Exeter, UK
| | - Sinead English
- School of Biological Sciences, University of Bristol, UK
| | - Olof Leimar
- Department of Zoology, Stockholm University, Sweden
| | | | - Suvi Ruuskanen
- Department of Biological and Environmental Science, University of Jyväskylä, Finland
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32
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Mentesana L, Hau M. Glucocorticoids in a warming world: Do they help birds to cope with high environmental temperatures? Horm Behav 2022; 142:105178. [PMID: 35561643 DOI: 10.1016/j.yhbeh.2022.105178] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/09/2022] [Accepted: 04/16/2022] [Indexed: 11/04/2022]
Abstract
Climate change is threatening biodiversity world-wide. One of its most prominent manifestations are rising global temperatures and higher frequencies of heat waves. High environmental temperatures may be particularly challenging for endotherms, which expend considerable parts of their energy budget and water resources on thermoregulation. Thermoregulation involves phenotypic plasticity in behavioral and physiological traits. Information on causal mechanisms that support plastic thermoregulatory strategies is key to understand how environmental information is transmitted and whether they impose trade-offs or constraints that determine how endotherms cope with climate warming. In this review, we focus on glucocorticoids, metabolic hormones that orchestrate plastic responses to various environmental stimuli including temperature. To evaluate how they may mediate behavioral and physiological responses to high environmental temperatures, we 1) briefly review the major thermoregulatory strategies in birds; 2) summarize the functions of baseline and stress-induced glucocorticoid concentrations; 3) synthesize the current knowledge of the relationship between circulating glucocorticoids and high environmental temperatures in birds; 4) generate hypotheses for how glucocorticoids may support plastic thermoregulatory responses to high environmental temperatures that occur over different time-frames (i.e., acute, short- and longer-term); and 5) discuss open questions on how glucocorticoids, and their relationship with thermoregulation, may evolve. Throughout this review we highlight that our knowledge, particularly on free-living populations, is really limited and outline promising avenues for future research. As evolutionary endocrinologists we now need to step up and identify the costs, benefits, and evolution of glucocorticoid plasticity to elucidate how they may help birds cope with a warming world.
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Affiliation(s)
- Lucia Mentesana
- Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., 82319 Seewiesen, Germany.
| | - Michaela Hau
- Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., 82319 Seewiesen, Germany.
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33
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Mauro AA, Shah AA, Martin PR, Ghalambor CK. An Integrative Perspective on the Mechanistic Basis of Context Dependent Species Interactions. Integr Comp Biol 2022; 62:164-178. [PMID: 35612972 DOI: 10.1093/icb/icac055] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/10/2022] [Accepted: 05/19/2022] [Indexed: 11/13/2022] Open
Abstract
It has long been known that the outcome of species interactions depends on the environmental context in which they occur. Climate change research has sparked a renewed interest in context dependent species interactions because rapidly changing abiotic environments will cause species interactions to occur in novel contexts and researchers must incorporate this in their predictions of species' responses to climate change. Here we argue that predicting how the environment will alter the outcome of species interactions requires an integrative biology approach that focuses on the traits, mechanisms, and processes that bridge disciplines such as physiology, biomechanics, ecology, and evolutionary biology. Specifically, we advocate for quantifying how species differ in their tolerance and performance to both environmental challenges independent of species interactions, and in interactions with other species as a function of the environment. Such an approach increases our understanding of the mechanisms underlying outcomes of species interactions across different environmental contexts. This understanding will in turn help determine how the outcome of species interactions affects the relative abundance and distribution of the interacting species in nature. A general theme that emerges from this perspective is that species are unable to maintain high levels of performance across different environmental contexts because of trade-offs between physiological tolerance to environmental challenges and performance in species interactions. Thus, an integrative biology paradigm that focuses on the trade-offs across environments, the physiological mechanisms involved, and how the ecological context impacts the outcome of species interactions provides a stronger framework to understand why species interactions are context dependent.
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Affiliation(s)
- Alexander A Mauro
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA 94720
| | - Alisha A Shah
- W.K. Kellogg Biological Station, Department of Integrative Biology, Michigan State University, Hickory Corners, MI, USA
| | - Paul R Martin
- Department of Biology, Queens University, Kingston, ON, Canada
| | - Cameron K Ghalambor
- Department of Biology, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.,Department of Biology, Colorado State University, Fort Collins, CO 80523.,Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523
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34
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Brandl HB, Pruessner JC, Farine DR. The social transmission of stress in animal collectives. Proc Biol Sci 2022; 289:20212158. [PMID: 35538776 PMCID: PMC9091854 DOI: 10.1098/rspb.2021.2158] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 03/18/2022] [Indexed: 01/04/2023] Open
Abstract
The stress systems are powerful mediators between the organism's systemic dynamic equilibrium and changes in its environment beyond the level of anticipated fluctuations. Over- or under-activation of the stress systems' responses can impact an animal's health, survival and reproductive success. While physiological stress responses and their influence on behaviour and performance are well understood at the individual level, it remains largely unknown whether-and how-stressed individuals can affect the stress systems of other group members, and consequently their collective behaviour. Stressed individuals could directly signal the presence of a stressor (e.g. via an alarm call or pheromones), or an acute or chronic activation of the stress systems could be perceived by others (as an indirect cue) and spread via social contagion. Such social transmission of stress responses could then amplify the effects of stressors by impacting social interactions, social dynamics and the collective performance of groups. As the neuroendocrine pathways of the stress response are highly conserved among vertebrates, transmission of physiological stress states could be more widespread among non-human animals than previously thought. We therefore suggest that identifying the extent to which stress transmission modulates animal collectives represents an important research avenue.
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Affiliation(s)
- Hanja B. Brandl
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, 78457 Konstanz, Germany
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland
| | - Jens C. Pruessner
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
- Department of Psychology, University of Konstanz, 78457 Konstanz, Germany
| | - Damien R. Farine
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, 78457 Konstanz, Germany
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, ACT 2600, Australia
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35
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Bryant AR, Gabor CR, Swartz LK, Wagner R, Cochrane MM, Lowe WH. Differences in Corticosterone Release Rates of Larval Spring Salamanders ( Gyrinophilus porphyriticus) in Response to Native Fish Presence. BIOLOGY 2022; 11:484. [PMID: 35453684 PMCID: PMC9030379 DOI: 10.3390/biology11040484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/11/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022]
Abstract
Invasive fish predators are an important factor causing amphibian declines and may have direct and indirect effects on amphibian survival. For example, early non-lethal exposure to these stressors may reduce survival in later life stages, especially in biphasic species. In amphibians, the glucocorticoid hormone corticosterone is released by the hypothalamo-pituitary-interrenal axis (HPI), as an adaptive physiological response to environmental stressors. The corticosterone response (baseline and response to acute stressors) is highly flexible and context dependent, and this variation can allow individuals to alter their phenotype and behavior with environmental changes, ultimately increasing survival. We sampled larvae of the spring salamander (Gyrinophilus porphyriticus) from two streams that each contained predatory brook trout (Slavelinus fontinalis) in the lower reaches and no predatory brook trout in the upper reaches. We measured baseline and stress-induced corticosterone release rates of larvae from the lower and upper reaches using a non-invasive water-borne hormone assay. We hypothesized that corticosterone release rates would differ between larvae from fish-present reaches and larvae from fish-free reaches. We found that baseline and stressor-induced corticosterone release rates were downregulated in larvae from reaches with fish predators. These results indicate that individuals from reaches with predatory trout are responding to fish predators by downregulating corticosterone while maintaining an active HPI axis. This may allow larvae more time to grow before metamorphosing, while also allowing them to physiologically respond to novel stressors. However, prolonged downregulation of corticosterone release rates can impact growth in post-metamorphic individuals.
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Affiliation(s)
- Amanda R. Bryant
- Department of Biology, Texas State University, San Marcos, TX 78666, USA;
| | - Caitlin R. Gabor
- Department of Biology, Texas State University, San Marcos, TX 78666, USA;
| | | | - Ryan Wagner
- School of Environment and Natural Resources, The Ohio State University Columbus, Columbus, OH 43210, USA;
| | - Madaline M. Cochrane
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (M.M.C.); (W.H.L.)
| | - Winsor H. Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (M.M.C.); (W.H.L.)
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Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality. Animals (Basel) 2022; 12:ani12040522. [PMID: 35203230 PMCID: PMC8868550 DOI: 10.3390/ani12040522] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary Changes in cortisol fluctuations are used for stress monitoring. Methodologically, this is straight forward, because sample collection is simple and analytical methods advanced, but since cortisol is primarily a hormone that facilitates energy allocation, the interpretation of these measures is often complex. Acute elevations in cortisol levels are not per se bad, but may constitute an adaptive coping mechanism. Likewise, low cortisol levels do not always indicate the absence of a stressor. To distinguish between stress response qualities, a more fine-grained analyses of cortisol fluctuations is warranted. Cortisol excretion follows a diurnal pattern with high levels in the morning, decreasing throughout the day. Two regression coefficients describe this curve: the intercept (the constant with which levels change throughout the day) and the slope (curve steepness and direction). We assessed salivary cortisol intercepts and slopes in zoo-housed apes on routine days, enrichment days, and in the new ape house. While cortisol excretion increased on enrichment days, the daily decline of cortisol levels was not affected. The move to the new house seemingly was a major stressor as cortisol levels increased slightly and the circadian cortisol decrease was impaired. The combination of intercept and slope measures can differentiate between stress responses, thereby constituting a useful tool for stress monitoring. Abstract Monitoring changes in cortisol levels is a widespread tool for measuring individuals’ stress responses. However, an acute increase in cortisol levels does not necessarily denote an individual in distress, as increases in cortisol can be elicited by all factors that signal the need to mobilize energy. Nor are low levels of cortisol indicative for a relaxed, healthy individual. Therefore, a more fine-grained description of cortisol patterns is warranted in order to distinguish between cortisol fluctuations associated with different stress response qualities. In most species, cortisol shows a distinct diurnal pattern. Using a reaction norm approach, cortisol levels across the day can be described by the two regression coefficients: the intercept and the slope of the curve. We measured immunoreactive salivary cortisol in three zoo-housed ape species under three conditions (routine days, enrichment days, and after the move to a new house). We examined salivary cortisol intercepts (SCI) and salivary cortisol slopes (SCS) of the diurnal curves. SCI and SCS were independent from each other. SCI was highest on enrichment days and lowest on routine days. SCS was steep on routine days and blunted after the move. Only SCI was species-specific. Our study provides evidence that combining SCI and SCS measures allows us to differentiate between types of stress responses, thereby constituting a useful tool for welfare assessment.
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Petrullo L, Ren T, Wu M, Boonstra R, Palme R, Boutin S, McAdam AG, Dantzer B. Glucocorticoids coordinate changes in gut microbiome composition in wild North American red squirrels. Sci Rep 2022; 12:2605. [PMID: 35173201 PMCID: PMC8850573 DOI: 10.1038/s41598-022-06359-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/24/2022] [Indexed: 12/31/2022] Open
Abstract
The gut microbiome impacts host health and fitness, in part through the diversification of gut metabolic function and pathogen protection. Elevations in glucocorticoids (GCs) appear to reduce gut microbiome diversity in experimental studies, suggesting that a loss of microbial diversity may be a negative consequence of increased GCs. However, given that ecological factors like food availability and population density may independently influence both GCs and microbial diversity, understanding how these factors structure the GC-microbiome relationship is crucial to interpreting its significance in wild populations. Here, we used an ecological framework to investigate the relationship between GCs and gut microbiome diversity in wild North American red squirrels (Tamiasciurus hudsonicus). As expected, higher GCs predicted lower gut microbiome diversity and an increase in metabolic taxa. Surprisingly, but in line with prior empirical studies on wild animals, gastrointestinal pathogens decreased as GCs increased. Both dietary heterogeneity and an upcoming food pulse exhibited direct effects on gut microbiome diversity, whereas conspecific density and reproductive activity impacted diversity indirectly via changes in host GCs. Our results provide evidence of a gut-brain axis in wild red squirrels and highlight the importance of situating the GC-gut microbiome relationship within an ecological framework.
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Affiliation(s)
- Lauren Petrullo
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48108, USA.
| | - Tiantian Ren
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Martin Wu
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Rudy Boonstra
- Department of Biological Sciences, Centre for the Neurobiology of Stress, University of Toronto Scarborough, Toronto, ON, M1C 1A6, Canada
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterina ̈rplatz 1, 1210, Vienna, Austria
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Andrew G McAdam
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48108, USA.
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48108, USA.
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Taff CC, Zimmer C, Ryan TA, van Oordt DC, Aborn DA, Ardia DR, Johnson LS, Rose AP, Vitousek M. Individual variation in natural or manipulated corticosterone does not covary with circulating glucose in a wild bird. J Exp Biol 2022; 225:274518. [DOI: 10.1242/jeb.243262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022]
Abstract
Animals respond to sudden challenges with a coordinated set of physiological and behavioral responses that enhance the ability to cope with stressors. While general characteristics of the vertebrate stress response are well described, it is not as clear how individual components covary between- or within-individuals. A rapid increase in glucocorticoids coordinates the stress response and one of the primary downstream results is an increase in glucose availability via reduced glucose utilization. Here, we asked whether between- and within-individual variation in corticosterone directly predicted variation in glucose. We collected 2,673 paired glucose and corticosterone measures from 776 tree swallows (Tachycineta bicolor) from four populations spanning the species range. In adults, glucose and corticosterone both increased during a standardized restraint protocol in all four populations. Moreover, in one population experimentally increasing a precursor that stimulates corticosterone release resulted in a further increase in both measures. In contrast, nestlings did not show a robust glucose response to handling or manipulation. Despite this group level variation, there was very little evidence in any population that between-individual variation in corticosterone predicted between-individual variation in glucose regulation. Glucose was moderately repeatable within-individuals, but within-individual variation in glucose and corticosterone were unrelated. Our results highlight the fact that a strong response in one aspect of the coordinated acute stress response (corticosterone) does not necessarily indicate that specific downstream components, such as glucose, will show similarly strong responses. These results have implications for understanding the evolution of integrated stress response systems.
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Affiliation(s)
- Conor C. Taff
- Department of Ecology & Evolutionary Biology, Cornell University, USA
- Lab of Ornithology, Cornell University, USA
| | - Cedric Zimmer
- Department of Ecology & Evolutionary Biology, Cornell University, USA
- Laboratoire d'Ethologie Expérimentale et Comparée, LEEC, UR 4443, Université Sorbonne Paris Nord, France
| | - Thomas A. Ryan
- Department of Ecology & Evolutionary Biology, Cornell University, USA
| | - David Chang van Oordt
- Department of Ecology & Evolutionary Biology, Cornell University, USA
- Lab of Ornithology, Cornell University, USA
| | - David A. Aborn
- Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, USA
| | | | | | - Alexandra P. Rose
- Ecology and Evolutionary Biology Department, University of Colorado Boulder, USA
| | - Maren Vitousek
- Department of Ecology & Evolutionary Biology, Cornell University, USA
- Lab of Ornithology, Cornell University, USA
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McMahon EK, Youatt E, Cavigelli SA. A physiological profile approach to animal temperament: How to understand the functional significance of individual differences in behaviour. Proc Biol Sci 2022; 289:20212379. [PMID: 35016542 PMCID: PMC8753167 DOI: 10.1098/rspb.2021.2379] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/01/2021] [Indexed: 12/21/2022] Open
Abstract
Animal behaviour research has experienced a renewed interest in consistent individual differences (i.e. animal personality or temperament). Recent ecological studies have identified environmental conditions that give rise to the development and evolution of temperaments and to fitness-related outcomes of temperament. Additional literature has also described relationships between temperaments and physiological regulation. However, one-to-one relationships between one behavioural trait and one physiological system do not account for co-selection of behavioural and physiological traits, nor the complex signalling among physiological systems. In the current paper, we review the literature on multiple physiological processes associated with temperament, propose temperament-specific physiological profiles, and focus on next steps to understand the functional significance, evolution and maintenance of temperaments. We propose that to understand causes and consequences of temperament we need to characterize integrative physiological profiles associated with different temperaments.
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Affiliation(s)
- Elyse K. McMahon
- Ecology Graduate Program, Huck Institutes of the Life Sciences, Pennsylvania State University, 101 Life Sciences Building, University Park, PA 16802, USA
- Biobehavioral Health Department, 219 Biobehavioral Health Building, University Park, PA 16802, USA
| | - Elizabeth Youatt
- Psychology Department, Pennsylvania State University, 140 Moore Building, University Park, PA 16802, USA
| | - Sonia A. Cavigelli
- Biobehavioral Health Department, 219 Biobehavioral Health Building, University Park, PA 16802, USA
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Carli G, Farabollini F. Neuroendocrine correlates of stress and tonic immobility. PROGRESS IN BRAIN RESEARCH 2022; 271:229-251. [DOI: 10.1016/bs.pbr.2022.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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41
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Zimmer C, Woods HA, Martin LB. Information theory in vertebrate stress physiology. Trends Endocrinol Metab 2022; 33:8-17. [PMID: 34750063 DOI: 10.1016/j.tem.2021.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/01/2021] [Accepted: 10/09/2021] [Indexed: 11/21/2022]
Abstract
Information theory has been applied productively across biology, but it has been used minimally in endocrinology. Here, we advocate for the integration of information theory into stress endocrinology. Presently, the majority of models of stress center on the regulation of hormone concentrations, even though what interests most endocrinologists and matters in terms of individual health and evolutionary fitness is the information content of hormones. In neuroscience, the free energy principle, a concept offered to explain how the brain infers current and future states of the environment, could be a guide for resolving how information is instantiated in hormones such as the glucocorticoids. Here, we offer several ideas and promising options for research addressing how hormones encode and cells respond to information in glucocorticoids.
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Affiliation(s)
- Cedric Zimmer
- Global Health and Infectious Disease Research Center, University of South Florida, FL 33612, USA; Laboratoire d'Ethologie Expérimentale et Comparée, LEEC, UR 4443, Université Sorbonne Paris Nord, 93430, Villetaneuse, France.
| | - H Arthur Woods
- University of Montana, Division of Biological Sciences, Missoula, MT 59812, USA
| | - Lynn B Martin
- Global Health and Infectious Disease Research Center, University of South Florida, FL 33612, USA
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Luttbeg B, Beaty LE, Ambardar M, Grindstaff JL. Mathematical modeling reveals how the speed of endocrine regulation should affect baseline and stress-induced glucocorticoid levels. Horm Behav 2021; 136:105059. [PMID: 34508875 PMCID: PMC8629843 DOI: 10.1016/j.yhbeh.2021.105059] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 06/10/2021] [Accepted: 08/23/2021] [Indexed: 10/20/2022]
Abstract
Unpredictable environmental changes displace individuals from homeostasis and elicit a stress response. In vertebrates, the stress response is mediated mainly by glucocorticoids (GCs) which initiate physiological changes while minimizing allostatic overload. Individuals and species vary consistently in baseline and stress-induced GC levels and the speed with which GC levels can be upregulated or downregulated, but the extent to which variation in hormone regulation influences baseline and stress-induced GC levels is unclear. Using mathematical modeling, we tested how GC regulation rate, frequencies and durations of acute stressors, fitness functions, and allostatic overload affect GC levels during control and acute stress periods. As GC regulation rate slows, baseline and acute stress-induced GC levels become more similar. When the speed of up- and downregulation decreased, hormone levels became more linked to anticipated future conditions to avoid fitness costs of mismatching a new environmental state. More frequent acute stressors caused baseline and acute stress-induced GC levels to converge. When fitness was more tightly linked to hormone levels during acute stress periods than during control states, the speed of upregulation influenced optimal hormone levels more than the downregulation rate. With allostatic overload costs included, predicted GC levels were lower and more dependent on the frequency of past acute stressors. Our results show the value of optimality modeling to study the hormonal response to stressors and suggest GC levels depend on past and anticipated future environmental states as well as individual differences in hormone regulation.
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Affiliation(s)
- Barney Luttbeg
- Department of Integrative Biology, Oklahoma State University, OK 74078, United States.
| | - Lynne E Beaty
- School of Science, Penn State Erie, The Behrend College, Erie, PA 16563, United States
| | - Medhavi Ambardar
- Department of Biological Sciences, Fort Hays State University, Hays, KS 67601, United States
| | - Jennifer L Grindstaff
- Department of Integrative Biology, Oklahoma State University, OK 74078, United States
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Vullioud P, Mendonça R, Glauser G, Bennett N, Zöttl M, Katlein N, Leal R, Fuerst R, Clutton-Brock T. Increases in glucocorticoids are sufficient but not necessary to increase cooperative burrowing in Damaraland mole-rats. Horm Behav 2021; 135:105034. [PMID: 34320418 DOI: 10.1016/j.yhbeh.2021.105034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 06/01/2021] [Accepted: 07/06/2021] [Indexed: 01/24/2023]
Abstract
Despite widespread interest in the evolution of cooperative behaviour, the physiological mechanisms shaping their expression remain elusive. We tested the hypothesis that glucocorticoid (GC) hormones affect cooperative behaviour using captive Damaraland mole-rats (Fukomys damarensis), a cooperatively breeding mammal. Within groups, individuals routinely contribute to public goods that include foraging tunnels, which provide all group members access to the tubers of desert plants they feed on, communal food stores and nests. We found that experimental increases in glucocorticoid concentration (GCc) in non-breeding female helpers led them to be active for longer and to burrow more while active, raising their daily contributions to burrowing, but not food carrying or nest building. However, experimentally induced increases in burrowing did not lead to elevated GCc in helpers of both sexes. These results suggest that heightened GCc may stimulate some cooperative behaviours that are energetically demanding (a characteristic shared by many types of cooperative activities across species) but that the cooperative behaviours affected by GCc can also be regulated by other mechanisms.
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Affiliation(s)
| | - Rute Mendonça
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland; Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, South Africa
| | - Gaëtan Glauser
- Neuchatel Platform of Analytical Chemistry, Faculty of Sciences, University of Neuchâtel, Switzerland
| | - Nigel Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, South Africa
| | - Markus Zöttl
- Department of Zoology, University of Cambridge, Cambridge, UK; Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, Kalmar, Sweden
| | - Nathan Katlein
- Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa
| | - Rita Leal
- Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa
| | - Romain Fuerst
- Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa
| | - Tim Clutton-Brock
- Department of Zoology, University of Cambridge, Cambridge, UK; Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, South Africa
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Sandoval-Herrera NI, Mastromonaco GF, Becker DJ, Simmons NB, Welch KC. Inter- and intra-specific variation in hair cortisol concentrations of Neotropical bats. CONSERVATION PHYSIOLOGY 2021; 9:coab053. [PMID: 34267922 PMCID: PMC8278960 DOI: 10.1093/conphys/coab053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 06/13/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Quantifying hair cortisol has become popular in wildlife ecology for its practical advantages for evaluating stress. Before hair cortisol levels can be reliably interpreted, however, it is key to first understand the intrinsic factors explaining intra- and inter-specific variation. Bats are an ecologically diverse group of mammals that allow studying such variation. Given that many bat species are threatened or have declining populations in parts of their range, minimally invasive tools for monitoring colony health and identifying cryptic stressors are needed to efficiently direct conservation efforts. Here we describe intra- and inter-specific sources of variation in hair cortisol levels in 18 Neotropical bat species from Belize and Mexico. We found that fecundity is an important ecological trait explaining inter-specific variation in bat hair cortisol. Other ecological variables such as colony size, roost durability and basal metabolic rate did not explain hair cortisol variation among species. At the individual level, females exhibited higher hair cortisol levels than males and the effect of body mass varied among species. Overall, our findings help validate and accurately apply hair cortisol as a monitoring tool in free-ranging bats.
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Affiliation(s)
- Natalia I Sandoval-Herrera
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, M5S 3B2, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Ontario, M1C 1A4, Canada
| | | | - Daniel J Becker
- Department of Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Nancy B Simmons
- Department of Mammalogy, Division of Vertebrate Zoology, American Museum of Natural History, New York, NY, 10024-5102, USA
| | - Kenneth C Welch
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, M5S 3B2, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Ontario, M1C 1A4, Canada
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45
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Guindre-Parker S, Rubenstein DR. Long-Term Measures of Climate Unpredictability Shape the Avian Endocrine Stress Axis. Am Nat 2021; 198:394-405. [PMID: 34403319 DOI: 10.1086/715628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractThe vertebrate glucocorticoid stress response is an important mechanism facilitating pleiotropic phenotypic adjustments for coping with environmental change and optimizing fitness. Although circulating glucocorticoid hormones are mediators of plasticity that individuals can adjust rapidly in response to environmental challenges, they are also shaped by ecological selection. It remains unclear, however, how environmental variation on different timescales influences glucocorticoids. Here, we use an intraspecific comparative approach to determine how variation in precipitation on different timescales (months, years, decades) shapes distinct components of the glucocorticoid response. We sampled superb starlings (Lamprotornis superbus) at eight sites across Kenya in multiple years that differed in precipitation. Among-population variation in baseline glucocorticoids was shaped by both short- and long-term precipitation, whereas variation in stress-induced levels was poorly explained by precipitation on any timescale. Adrenal sensitivity, quantified via adrenocorticotropic hormone injections, was shaped by long-term precipitation and was highest in unpredictable environments. Together, these results suggest that variation in glucocorticoids can be best explained by environmental variation at timescales that extend beyond the lives of individuals, although baseline glucocorticoids also reflect short-term environmental conditions. Patterns of long-term precipitation may represent a microevolutionary selective pressure shaping the endocrine stress axis across populations and influencing how individuals cope with environmental change.
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46
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Buss N, Swierk L, Hua J. Amphibian breeding phenology influences offspring size and response to a common wetland contaminant. Front Zool 2021; 18:31. [PMID: 34172063 PMCID: PMC8228996 DOI: 10.1186/s12983-021-00413-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/17/2021] [Indexed: 11/23/2022] Open
Abstract
Background Increases in temperature variability associated with climate change have critical implications for the phenology of wildlife across the globe. For example, warmer winter temperatures can induce forward shifts in breeding phenology across taxa (“false springs”), which can put organisms at risk of freezing conditions during reproduction or vulnerable early life stages. As human activities continue to encroach on natural ecosystems, it is also important to consider how breeding phenology interacts with other anthropogenic stressors (e.g., pollutants). Using 14 populations of a widespread amphibian (wood frog; Rana sylvatica), we compared 1) growth; 2) tolerance to a common wetland contaminant (NaCl); and 3) the ability of tadpoles to acclimate to lethal NaCl exposure following sublethal exposure earlier in life. We evaluated these metrics across two breeding seasons (2018 and 2019) and across populations of tadpoles whose parents differed in breeding phenology (earlier- versus later-breeding cohorts). In both years, the earlier-breeding cohorts completed breeding activity prior to a winter storm and later-breeding cohorts completed breeding activities after a winter storm. The freezing conditions that later-breeding cohorts were exposed to in 2018 were more severe in both magnitude and duration than those in 2019. Results In 2018, offspring of the later-breeding cohort were larger but less tolerant of NaCl compared to offspring of the earlier-breeding cohort. The offspring of the earlier-breeding cohort additionally were able to acclimate to a lethal concentration of NaCl following sublethal exposure earlier in life, while the later-breeding cohort became less tolerant of NaCl following acclimation. Interestingly, in 2019, the warmer of the two breeding seasons, we did not detect the negative effects of later breeding phenology on responses to NaCl. Conclusions These results suggest that phenological shifts that expose breeding amphibians to freezing conditions can have cascading consequences on offspring mass and ability to tolerate future stressors but likely depends on the severity of the freeze event. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00413-0.
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Affiliation(s)
- Nicholas Buss
- Biological Sciences Department, Binghamton University, State University of New York, 4400 Vestal Parkway East, Binghamton, NY, 13902, USA.
| | - Lindsey Swierk
- Biological Sciences Department, Binghamton University, State University of New York, 4400 Vestal Parkway East, Binghamton, NY, 13902, USA.,Environmental Studies Program, Binghamton University, State University of New York, 4400 Vestal Parkway East, Binghamton, NY, 13902, USA
| | - Jessica Hua
- Biological Sciences Department, Binghamton University, State University of New York, 4400 Vestal Parkway East, Binghamton, NY, 13902, USA
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DeRango EJ, Schwarz JFL, Piedrahita P, Páez‐Rosas D, Crocker DE, Krüger O. Hormone-mediated foraging strategies in an uncertain environment: Insights into the at-sea behavior of a marine predator. Ecol Evol 2021; 11:7579-7590. [PMID: 34188836 PMCID: PMC8216952 DOI: 10.1002/ece3.7590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/22/2022] Open
Abstract
Hormones are extensively known to be physiological mediators of energy mobilization and allow animals to adjust behavioral performance in response to their environment, especially within a foraging context.Few studies, however, have narrowed focus toward the consistency of hormonal patterns and their impact on individual foraging behavior. Describing these relationships can further our understanding of how individuals cope with heterogeneous environments and exploit different ecological niches.To address this, we measured between- and within-individual variation of basal cortisol (CORT), thyroid hormone T3, and testosterone (TEST) levels in wild adult female Galápagos sea lions (Zalophus wollebaeki) and analyzed how these hormones may be associated with foraging strategies. In this marine predator, females exhibit one of three spatially and temporally distinct foraging patterns (i.e., "benthic," "pelagic," and "night" divers) within diverse habitat types.Night divers differentiated from other strategies by having lower T3 levels. Considering metabolic costs, night divers may represent an energetically conservative strategy with shorter dive durations, depths, and descent rates to exploit prey which migrate up the water column based on vertical diel patterns.Intriguingly, CORT and TEST levels were highest in benthic divers, a strategy characterized by congregating around limited, shallow seafloors to specialize on confined yet reliable prey. This pattern may reflect hormone-mediated behavioral responses to specific risks in these habitats, such as high competition with conspecifics, prey predictability, or greater risks of predation.Overall, our study highlights the collective effects of hormonal and ecological variation on marine foraging. In doing so, we provide insights into how mechanistic constraints and environmental pressures may facilitate individual specialization in adaptive behavior in wild populations.
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Affiliation(s)
| | | | - Paolo Piedrahita
- Facultad de Ciencias de la VidaEscuela Superior Politécnica del LitoralGuayaquilEcuador
| | - Diego Páez‐Rosas
- Universidad San Francisco de QuitoGalápagos Science CenterIsla San CristobalEcuador
- Dirección Parque Nacional GalápagosOficina Técnica San CristóbalIsla San CristóbalEcuador
| | | | - Oliver Krüger
- Department of Animal BehaviourBielefeld UniversityBielefeldGermany
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Forsburg ZR, Guzman A, Gabor CR. Artificial light at night (ALAN) affects the stress physiology but not the behavior or growth of Rana berlandieri and Bufo valliceps. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 277:116775. [PMID: 33639600 DOI: 10.1016/j.envpol.2021.116775] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 02/03/2021] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
Artificial light at night (ALAN) alters the natural light dark patterns in ecosystems. ALAN can have a suite of effects on community structure and is a driver of evolutionary processes that influences a range of behavioral and physiological traits. Our understanding of possible effects of ALAN across species amphibians is lacking and research is warranted as ALAN could contribute to stress and declines of amphibian populations, particularly in urban areas. We tested the hypothesis that exposure to constant light or pulsed ALAN would physiologically stress Rio Grande leopard frog (Rana berlandieri) and Gulf Coast toad (Bufo valliceps) tadpoles. We reared tadpoles under constant or pulsed (on and off again) ALAN for 14 days and measured corticosterone release rates over time using a non-invasive water-borne hormone protocol. ALAN treatments did not affect behavior or growth. Tadpoles of both species had higher corticosterone (cort) release rates after 14 days of constant light exposure. Leopard frog tadpoles had lower cort release rates after exposure to pulsed ALAN while toad tadpoles had higher cort release rates. These results suggest that short-term exposure to constant or pulsed light at night may contribute to stress in tadpoles but that each species differentially modulated their cort response to ALAN exposure and a subsequent stressor. This flexibility in the upregulation and downregulation of hypothalamic-pituitary-interrenal axis response may indicate an alternative mechanism for diminishing the deleterious effects of chronic stress. Nonetheless, ALAN should be considered in management and conservation plans for amphibians.
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Affiliation(s)
- Zachery R Forsburg
- Department of Biology, Texas State University, San Marcos, TX, 78666, USA.
| | - Alex Guzman
- Department of Biology, Texas State University, San Marcos, TX, 78666, USA
| | - Caitlin R Gabor
- Department of Biology, Texas State University, San Marcos, TX, 78666, USA
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Mutwill AM, Schielzeth H, Zimmermann TD, Richter SH, Kaiser S, Sachser N. Individuality meets plasticity: Endocrine phenotypes across male dominance rank acquisition in guinea pigs living in a complex social environment. Horm Behav 2021; 131:104967. [PMID: 33862349 DOI: 10.1016/j.yhbeh.2021.104967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 11/28/2022]
Abstract
The time of dominance rank acquisition is a crucial phase in male life history that often affects reproductive success and hence fitness. Hormones such as testosterone and glucocorticoids can influence as well as be affected by this process. At the same time, hormone concentrations can show large individual variation. The extent to which such variation is repeatable, particularly in dynamic social settings, is a question of current interest. The aim of the present study was therefore to investigate how dominance rank and individual differences contribute to variance in hormone concentrations during male rank acquisition in a complex social environment. For this purpose, dominance rank as well as baseline testosterone, baseline cortisol, and cortisol responsiveness after exposure to a novel environment were determined in colony-housed guinea pig males from late adolescence through adulthood. Hormone-dominance relationships and repeatability of hormone measures beyond their relation to rank were assessed. There was a significant positive relationship between baseline testosterone and rank, but this link became weaker with increasing age. Baseline cortisol or cortisol responsiveness, in contrast, were not significantly related to dominance. Notably, all three endocrine parameters were significantly repeatable independent of dominance rank from late adolescence through adulthood. Baseline testosterone and cortisol responsiveness showed a significantly higher repeatability than baseline cortisol. This suggests that testosterone titres and cortisol responsiveness represent stable individual attributes even under complex social conditions.
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Affiliation(s)
- Alexandra M Mutwill
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany; Münster Graduate School of Evolution, University of Münster, Hüfferstr. 1a, 48149 Münster, Germany.
| | - Holger Schielzeth
- Population Ecology Group, Institute of Ecology, Friedrich Schiller University, Dornburgerstr. 159, 07743 Jena, Germany
| | - Tobias D Zimmermann
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany
| | - S Helene Richter
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany; Münster Graduate School of Evolution, University of Münster, Hüfferstr. 1a, 48149 Münster, Germany
| | - Sylvia Kaiser
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany; Münster Graduate School of Evolution, University of Münster, Hüfferstr. 1a, 48149 Münster, Germany
| | - Norbert Sachser
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany; Münster Graduate School of Evolution, University of Münster, Hüfferstr. 1a, 48149 Münster, Germany
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50
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Baugh AT, Gall MD, Silver SC, Bee MA. Moderately elevated glucocorticoids increase mate choosiness but do not affect sexual proceptivity or preferences in female gray treefrogs. Horm Behav 2021; 130:104950. [PMID: 33556376 DOI: 10.1016/j.yhbeh.2021.104950] [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: 08/14/2020] [Revised: 01/15/2021] [Accepted: 01/30/2021] [Indexed: 01/20/2023]
Abstract
Glucocorticoids (GCs) are rarely studied in the context of female mate choice, despite the expression of receptors for these products in sexual, sensory and decision-making brain areas. Here we investigated the effects of GC concentrations on three aspects of female sexual behavior in breeding Cope's gray treefrogs (Hyla chrysoscelis): proceptivity-a measure of sexual motivation, intraspecific mate preferences, and mate choosiness. To our knowledge this is the first experimental study on the endocrine basis of mate choosiness. We predicted that mate choosiness-forfeiting an initial mate preference to pursue a suddenly more attractive mate-would be particularly impacted by elevated GCs with moderate GC levels associated with greater choosiness. We found support for this predicted inverted-U relationship. Females in the control group (no injection) showed no change in choosiness across timepoints. In contrast, females in the vehicle, Low (20 ng g-1) and High (180 ng g-1) corticosterone groups exhibited a nominal decline in choosiness after injection, suggesting that the experience of injection has little or perhaps slightly suppressive effects on female choosiness. Females in the moderate dose group (60 ng g-1), however, exhibited a significant increase (>100%) in choosiness. Further, we found no effect of elevated GCs on sexual proceptivity or the species-typical preference for longer calls. These findings may reflect a buffering of primary sensory areas in the brain against elevated GCs. The recruitment of other cognitive processes during active decision-making, however, may facilitate GC modulation of mate choosiness, thereby promoting tactical plasticity at this critical life history juncture.
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Affiliation(s)
- Alexander T Baugh
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
| | - Megan D Gall
- Department of Biology, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604, USA
| | - Stewart C Silver
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
| | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota - Twin Cities, 1479 Gortner Ave, St. Paul, MN 55108, USA; Graduate Program in Neuroscience, University of Minnesota - Twin Cities, 321 Church Street SE, Minneapolis, MN 55455, USA
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