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de Oliveira Rosa SA, Titon Junior B, de Figueiredo AC, Lima AS, Gomes FR, Titon SCM. Baseline and stress-induced changes in plasma bacterial killing ability against gram-negative bacteria are partially mediated by the complement system in Rhinella diptycha toads. Comp Biochem Physiol A Mol Integr Physiol 2024; 297:111701. [PMID: 39029618 DOI: 10.1016/j.cbpa.2024.111701] [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: 03/01/2024] [Revised: 06/26/2024] [Accepted: 07/15/2024] [Indexed: 07/21/2024]
Abstract
The plasma bacterial killing ability (BKA) is modulated by the stress response in vertebrates, including amphibians. The complement system is an effector mechanism comprised of a set of proteins present in the plasma that once activated can promote bacterial lysis. Herein, we investigated whether changes in plasma BKA as a result of the acute stress response and an immune challenge are mediated by the complement system in Rhinella diptycha toads. Additionally, we investigated whether the observed changes in plasma BKA are associated with changes in plasma corticosterone levels (CORT). We subjected adult male toads to a restraint or an immune challenge (with three concentrations of Aeromonas hydrophila heat inactivated), and then evaluated the plasma BKA against A. hydrophila, in vitro. We determined the complement system activity on plasma BKA, by treating the plasma (baseline, 1 h and 24 h post-restraint, and after the immune challenge) with ethylenediaminetetraacetic acid, heat, or protease. Our results showed increased CORT 1 h and 24 h after restraint and decreased plasma BKA 24 h post-restraint. The inhibitors of the complement system decreased the plasma BKA compared with untreated plasma at all times (baseline, 1 h, and 24 h after restraint), demonstrating that the plasma BKA activity is partially mediated by the complement system. The immune challenge increased CORT, with the highest values being observed in the highest bacterial concentration, compared with control. The plasma BKA was not affected by the immune challenge but was demonstrated to be partially mediated by the complement system. Our results demonstrated that restraint and the immune challenge activated the hypothalamus-pituitary-interrenal axis, by increasing plasma CORT levels in R. diptycha. Also, our results demonstrated the complement system is participative in the plasma BKA for baseline and post-stress situations in these toads.
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Affiliation(s)
| | - Braz Titon Junior
- Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
| | | | - Alan Siqueira Lima
- Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
| | - Fernando Ribeiro Gomes
- Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
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Case BF, Groffen J, Galligan TM, Bodinof Jachowski CM, Hallagan JJ, Hildreth SB, Alaasam V, Keith Ray W, Helm RF, Hopkins WA. Androgen and glucocorticoid profiles throughout extended uniparental paternal care in the eastern hellbender salamander (Cryptobranchus a. alleganiensis). Gen Comp Endocrinol 2024; 355:114547. [PMID: 38772453 DOI: 10.1016/j.ygcen.2024.114547] [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: 11/21/2023] [Revised: 05/08/2024] [Accepted: 05/15/2024] [Indexed: 05/23/2024]
Abstract
The behavioral endocrinology associated with reproduction and uniparental male care has been studied in teleosts, but little is known about hormonal correlates of uniparental male care in other ectotherms. To address this gap, we are the first to document the seasonal steroid endocrinology of uniparental male hellbender salamanders during the transition from pre-breeding to nest initiation, and through the subsequent eight months of paternal care. In doing so, we investigated the correlates of nest fate and clutch size, exploring hellbenders' alignment with several endocrinological patterns observed in uniparental male fish. Understanding the endocrinology of hellbender paternal care is also vital from a conservation perspective because high rates of nest failure were recently identified as a factor causing population declines in this imperiled species. We corroborated previous findings demonstrating testosterone and dihydrotestosterone (DHT) to be the primary androgens in hellbender reproduction, and that cortisol circulates as the most abundant glucocorticoid. However, we were unable to identify a prolactin or a "prolactin-like" peptide in circulation prior to or during parental care. We observed ∼ 80 % declines in both primary androgens during the transition from pre-breeding to nest initiation, and again as paternal care progressed past its first month. In the days immediately following nest initiation, testosterone and DHT trended higher in successful individuals, but did not differ with males' clutch size. We did not observe meaningful seasonality in baseline glucocorticoids associated with breeding or nesting. In contrast, stress-induced glucocorticoids were highest at pre-breeding and through the first two months of care, before declining during the latter-most periods of care as larvae approach emergence from the nest. Neither baseline nor stress-induced glucocorticoids varied significantly with either nest fate or clutch size. Both stress-induced cortisol and corticosterone were positively correlated with total length, a proxy for age in adult hellbenders. This is consistent with age-related patterns in some vertebrates, but the first such pattern observed in a wild amphibian population. Generally, we found that nesting hellbenders adhere to some but not all of the endocrinological patterns observed in uniparental male teleosts prior to and during parental care.
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Affiliation(s)
- Brian F Case
- Virginia Tech, Department of Fish and Wildlife Conservation, Blacksburg, VA 24060, USA.
| | - Jordy Groffen
- Virginia Tech, Department of Fish and Wildlife Conservation, Blacksburg, VA 24060, USA
| | - Thomas M Galligan
- Virginia Tech, Department of Fish and Wildlife Conservation, Blacksburg, VA 24060, USA
| | | | - John J Hallagan
- Virginia Tech, Department of Fish and Wildlife Conservation, Blacksburg, VA 24060, USA
| | - Sherry B Hildreth
- Virginia Tech, Fralin Life Sciences Institute, Blacksburg, VA 24060, USA
| | - Valentina Alaasam
- Virginia Tech, Department of Fish and Wildlife Conservation, Blacksburg, VA 24060, USA
| | - W Keith Ray
- Virginia Tech, Fralin Life Sciences Institute, Blacksburg, VA 24060, USA
| | - Richard F Helm
- Virginia Tech, Department of Biochemistry, Blacksburg, VA 24060, USA
| | - William A Hopkins
- Virginia Tech, Department of Fish and Wildlife Conservation, Blacksburg, VA 24060, USA
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Titon Junior B, Barsotti AMG, Titon SCM, Vaz RI, de Figueiredo AC, Vasconcelos-Teixeira R, Navas CA, Gomes FR. Baseline and stress-induced steroid plasma levels and immune function vary annually and are associated with vocal activity in male toads (Rhinella icterica). Gen Comp Endocrinol 2024; 354:114517. [PMID: 38615755 DOI: 10.1016/j.ygcen.2024.114517] [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: 12/07/2023] [Revised: 03/19/2024] [Accepted: 04/06/2024] [Indexed: 04/16/2024]
Abstract
Theoretical models predict that elevated androgen and glucocorticoid levels in males during the reproductive season promote immunosuppression. However, some studies report decreased stress response during this season. This study investigated annual variation in plasma corticosterone and testosterone levels, plasma bacterial killing ability (BKA), and neutrophil to lymphocyte ratio (NLR) in free-living male toads (Rhinella icterica). Toads were sampled in the field (baseline) and 1 h-post restraint over five months, and we considered the occurrence of vocal activity. Baseline corticosterone, testosterone, and BKA showed higher values during the reproductive period, specifically in calling male toads. The NLR was similar throughout the year, but higher values were observed in calling toads. Moreover, baseline NLR and BKA were positively correlated with both testosterone and corticosterone, suggesting higher steroid levels during reproduction are associated with enhanced cellular and humoral immunity. Despite fluctuation of baseline values, post-restraint corticosterone levels remained uniform over the year, indicating that toads reached similar maximum values throughout the year. Testosterone levels decreased following restraint before one specific reproductive period but increased in response to restraint during and after this period. Meanwhile, BKA decreased due to restraint only after the reproductive period, indicating immune protection and resilience to immunosuppression by stressors associated with steroid hormones during reproduction. Our results show that baseline and stress-induced hormonal and immune regulation varies throughout the year and are associated with vocal activity in R. icterica males, indicating a possible compromise between steroids and immune function in anuran males.
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Affiliation(s)
- Braz Titon Junior
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil.
| | | | | | - Renata Ibelli Vaz
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | - Aymam Cobo de Figueiredo
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | | | - Carlos A Navas
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | - Fernando Ribeiro Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
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Clarke E, Heugten KAV, Tollefson TN, Ridgley FN, Smith D, Brown JL, Scott H, Minter LJ. Comparison of Corticosterone Concentrations in Dermal Secretions and Urine in Free-Ranging Marine Toads ( Rhinella marina) in Human Care. Vet Med Int 2023; 2023:1467549. [PMID: 37766874 PMCID: PMC10522434 DOI: 10.1155/2023/1467549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 08/25/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Corticosterone concentrations have been measured in amphibians by collecting blood or urine samples. However, blood sampling is invasive, and urine can be difficult to collect. A novel method of swabbing the skin of an amphibian has been utilized in numerous species but has not been verified in marine toads (Rhinella marina). This pilot study tested dermal swabs as a noninvasive method for collecting and measuring dermal corticosterone secretions. Swabs were used to collect dermal secretion samples from sixty-six free-ranging marine toads collected on Zoo Miami grounds. The subsequent day the toads were shipped to the North Carolina Zoo where dermal samples were collected again. Additional dermal and urine samples were collected on days 9, 15, 32, and 62 under human care to measure corticosterone concentrations. There was no significant correlation (P ≥ 0.05) noted between corticosterone concentrations reported in dermal swabs and those in urine samples at all four of the euthanasia time points or between the corticosterone concentrations reported in either urine or dermal swabs and the weight of the toads. Dermal swab concentrations (ng/mL) were significantly higher (P ≤ 0.05) on the day of capture (0.64 ± 0.03) and the day of arrival (0.67 ± 0.03) than on day 15 (0.47 ± 0.03). The urine corticosterone concentrations decreased while the toads were in human care with a significant decrease (P ≤ 0.05) between days 9 (0.45 ± 0.07) and 32 (0.21 ± 0.06). This study demonstrated that dermal swabs can be used to collect marine toad corticosterone concentration samples.
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Affiliation(s)
- Emma Clarke
- Department of Clinical Sciences, North Carolina State University, College of Veterinary Medicine, 1060 William Moore Dr., Raleigh, NC 27607, USA
| | - Kimberly Ange-van Heugten
- Department of Animal Science, North Carolina State University, 120 W. Broughton Dr., Raleigh, NC 27695, USA
- Environment Medicine Consortium, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27607, USA
| | - Troy N. Tollefson
- Mazuri® Exotic Animal Nutrition, PMI Nutrition, 4001 Lexington Ave. North, Arden Hills, MN 55126, USA
| | - Frank N. Ridgley
- The Conservation and Research Department, Zoo Miami, 12400 SW 152nd St., Miami, FL 33177, USA
| | - Dustin Smith
- North Carolina Zoo, 4401 Zoo Pkwy, Asheboro, NC 27205, USA
| | - Janine L. Brown
- Smithsonian Conservation Biology Institute, 1500 Remount Rd., Front Royal, VA 22630, USA
| | - Heather Scott
- North Carolina Zoo, 4401 Zoo Pkwy, Asheboro, NC 27205, USA
| | - Larry J. Minter
- Department of Clinical Sciences, North Carolina State University, College of Veterinary Medicine, 1060 William Moore Dr., Raleigh, NC 27607, USA
- Environment Medicine Consortium, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27607, USA
- North Carolina Zoo, 4401 Zoo Pkwy, Asheboro, NC 27205, USA
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Gomes FR, Madelaire CB, Moretti EH, Titon SCM, Assis VR. Immunoendocrinology and Ecoimmunology in Brazilian Anurans. Integr Comp Biol 2022; 62:1654-1670. [PMID: 35411921 DOI: 10.1093/icb/icac014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
This paper reviews several aspects of immunoendocrinology and ecoimmunology in Brazilian species of anurans under investigation for more than a decade, including (1) patterns of annual covariation of circulating steroids, calling behavior and innate immunity, (2) endocrine and immune correlates of calling performance, (3) behavioral and physiological correlates of parasite load, (4) thermal sensitivity of immune function, and (5) endocrine and immunomodulation by experimental exposure to acute and chronic stressors, as well as to endocrine manipulations and simulated infections. Integrated results have shown an immunoprotective role of increased steroid plasma levels during reproductive activity in calling males. Moreover, a higher helminth parasite load is associated with changes in several behavioral and physiological traits under field conditions. We also found anuran innate immunity is generally characterized by eurythermy, with maximal performance observed in temperatures close to normal and fever thermal preferendum. Moreover, the aerobic scope of innate immune response is decreased at fever thermal preferendum. Experimental exposure to stressors results in increased corticosterone plasma levels and immune redistribution, with an impact on immune function depending on the duration of the stress exposure. Interestingly, the fate of immunomodulation by chronic stressors also depends in part on individual body condition. Acute treatment with corticosterone generally enhances immune function, while prolonged exposure results in immunosuppression. Still, the results of hormonal treatment are complex and depend on the dose, duration of treatment, and the immune variable considered. Finally, simulated infection results in complex modulation of the expression of cytokines, increased immune function, activation of the Hypothalamus-Pituitary-Interrenal axis, and decreased activity of the Hypothalamus-Pituitary-Gonadal axis, as well as reduced melatonin plasma levels, suggesting that anurans have a functional Immune-Pineal axis, homologous to that previously described for mammals. These integrated and complementary approaches have contributed to a better understanding of physiological mechanisms and processes, as well as ecological and evolutionary implications of anuran immunoendocrinology.
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Affiliation(s)
- Fernando Ribeiro Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil
| | - Carla Bonetti Madelaire
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil.,School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Eduardo Hermógenes Moretti
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Professor Lineu Prestes, 1730, São Paulo, SP 05508-900, Brasil
| | - Stefanny Christie Monteiro Titon
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil
| | - Vania Regina Assis
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil
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Midttun HLE, Øverli Ø, Tudorache C, Mayer I, Johansen IB. Non-invasive sampling of water-borne hormones demonstrates individual consistency of the cortisol response to stress in laboratory zebrafish (Danio rerio). Sci Rep 2022; 12:6278. [PMID: 35428763 PMCID: PMC9012867 DOI: 10.1038/s41598-022-10274-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 04/04/2022] [Indexed: 12/28/2022] Open
Abstract
Glucocorticoid (GC) stress hormones are well-known for their impact on phenotypic traits ranging from immune function to behaviour and cognition. For that reason, consistent aspects of an individual's physiological stress response (i.e. GC responsiveness) can predict major elements of life-history trajectory. Zebrafish (Danio rerio) emerge as a promising model to study such consistent trait correlations, including the development of individual stress coping styles, i.e. consistent associations between physiological and behavioral traits. However, consistency in GC responsiveness of this popular animal model remains to be confirmed. Such a study has so far been hampered by the small-bodied nature and insufficient blood volume of this species to provide repeated measurements of circulating GCs. Here, we adopted a technique that allows for repeated, non-invasive sampling of individual zebrafish by quantifying GCs from holding water. Our findings indicate consistency of the magnitude of post-stress GC production over several consecutive stress events in zebrafish. Moreover, water-borne GCs reflect individual variation in GC responsiveness with the strongest consistency seen in males.
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Affiliation(s)
- H L E Midttun
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Ø Øverli
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - C Tudorache
- Institute for Biology, Leiden University, Leiden, The Netherlands
| | - I Mayer
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - I B Johansen
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
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Grindstaff JL, Beaty LE, Ambardar M, Luttbeg B. Integrating theoretical and empirical approaches for a robust understanding of endocrine flexibility. J Exp Biol 2022; 225:274311. [PMID: 35258612 PMCID: PMC8987727 DOI: 10.1242/jeb.243408] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
There is growing interest in studying hormones beyond single 'snapshot' measurements, as recognition that individual variation in the endocrine response to environmental change may underlie many rapid, coordinated phenotypic changes. Repeated measures of hormone levels in individuals provide additional insight into individual variation in endocrine flexibility - that is, how individuals modulate hormone levels in response to the environment. The ability to quickly and appropriately modify phenotype is predicted to be favored by selection, especially in unpredictable environments. The need for repeated samples from individuals can make empirical studies of endocrine flexibility logistically challenging, but methods based in mathematical modeling can provide insights that circumvent these challenges. Our Review introduces and defines endocrine flexibility, reviews existing studies, makes suggestions for future empirical work, and recommends mathematical modeling approaches to complement empirical work and significantly advance our understanding. Mathematical modeling is not yet widely employed in endocrinology, but can be used to identify innovative areas for future research and generate novel predictions for empirical testing.
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Affiliation(s)
| | - Lynne E Beaty
- School of Science, Penn State Erie - The Behrend College, Erie, PA 16563, USA
| | - Medhavi Ambardar
- Department of Biological Sciences, Fort Hays State University, Hays, KS 67601, USA
| | - Barney Luttbeg
- Department of Integrative Biology, Oklahoma State University, OK 74078, USA
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URINARY CORTICOSTERONE CONCENTRATIONS IN FREE-RANGING AND MANAGED CANE TOADS ( RHINELLA MARINA). J Zoo Wildl Med 2022; 52:1234-1240. [PMID: 34998294 DOI: 10.1638/2020-0221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2021] [Indexed: 11/21/2022] Open
Abstract
Approximately 40% of amphibian species are threatened with extinction. The welfare of amphibians maintained under managed care as assurance populations is of vital importance to guard against extinction and provide a viable source population for future reintroduction. To manage amphibian species properly ex situ, it is important to understand how stress levels change over time when animals are removed from the wild and placed into managed environments. Corticosterone was analyzed in urine samples from free-ranging cane toads (Rhinella marina, n = 55) in Miami, FL, and under managed care for 22 (n = 48), 50 (n = 11), 81 (n = 25), or 119 (n = 10) days. Concentrations of corticosterone in free-ranging toad urine averaged 1.74 ± 0.195 ng/ml urine specific gravity (sp. gr.), which was greater (P < 0.05) than other time points (day 22: 0.77 ± 0.114 L; day 81: 0.85 ± 0.191 ng/ml sp. gr.; day 119: 0.58 ± 0.093 ng/ml sp. gr.), except day 50 (0.91 ± 0.274 ng/ml sp. gr.), which was not different from free-ranging or managed care values. Thus, corticosterone was lower in cane toads under managed care compared with those sampled in the wild, suggesting that managed care is not a stressor for this species.
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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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Kraus S, Krüger O, Guenther A. Zebra finches bi-directionally selected for personality differ in repeatability of corticosterone and testosterone. Horm Behav 2020; 122:104747. [PMID: 32217065 DOI: 10.1016/j.yhbeh.2020.104747] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/16/2022]
Abstract
Consistent between-individual differences in behaviour have been documented across the animal kingdom. Such variation between individuals has been shown to be the basis for selection and to act as a pacemaker for evolutionary change. Recently, equivocal evidence suggests that such consistent between-individual variation is also present in hormones. This observation has sparked interest in understanding the mechanisms shaping individual differences, temporal consistency and heritability of hormonal phenotypes and to understand, if and to what extent hormonal mechanisms are involved in mediating consistent variation in behaviour between individuals. Here, we used zebra finches of the fourth generation of bi-directionally selected lines for three independent behaviours: aggression, exploration and fearlessness. We investigated how these behaviours responded to artificial selection and tested their repeatability. We further tested for repeatability of corticosterone and testosterone across and within lines. Moreover, we are presenting the decomposed variance components for within-individual variance (i.e. flexibility) and between-individual variance (i.e. more or less pronounced differences between individuals) and investigate their contribution to repeatability estimates. Both hormones as well as the exploration and fearlessness but not aggressiveness, were repeatable. However, variance components and hence repeatability differed between lines and were often lower than in unselected control animals, mainly because of a reduction in between-individual variance. Our data show that artificial selection (including active selection and genetic drift) can affect the mean and variance of traits. We stress the importance for understanding how variable a trait is both between and within individuals to assess the selective value of a trait.
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Affiliation(s)
- Sabine Kraus
- Department of Animal Behaviour, Bielefeld University, Germany.
| | - Oliver Krüger
- Department of Animal Behaviour, Bielefeld University, Germany.
| | - Anja Guenther
- Department of Animal Behaviour, Bielefeld University, Germany; Max Planck Institute for Evolutionary Biology, Plön, Germany.
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11
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Madelaire CB, Cassettari BDO, Gomes FR. Immunomodulation by testosterone and corticosterone in toads: Experimental evidences from transdermal application. Gen Comp Endocrinol 2019; 273:227-235. [PMID: 30195026 DOI: 10.1016/j.ygcen.2018.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 08/31/2018] [Accepted: 09/04/2018] [Indexed: 10/28/2022]
Abstract
Androgens and glucocorticoids play important roles in vertebrate's reproduction and display complex immunomodulatory functions that may affect survival. In anurans, testosterone and corticosterone are correlated to sexual behavior, reproduction, and immune function. Male toads (Rhinella jimi) were treated with acute doses of testosterone (T) and corticosterone (CORT) and immune variables (plasma bacterial killing ability [BKA], swelling after phytohemagglutinin [PHA] injection and the time point of maximum PHA swelling response) were measured. Transdermal T and CORT application increased androgen (T-DHT) and CORT plasma levels after 1 h of treatment, respectively, without a dose-specific effect. Transdermal T treatment did not affect BKA or PHA swelling response. Individuals treated with transdermal CORT showed an earlier maximum PHA swelling response and a tendency of lower BKA 15 h after treatment. Our results indicated that an acute experimental increase of CORT plasma levels diminished time for inflammatory resolution and suppressed non-cellular innate response.
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Affiliation(s)
- Carla Bonetti Madelaire
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav 14 n 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
| | - Bruna de Oliveira Cassettari
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav 14 n 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Fernando Ribeiro Gomes
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav 14 n 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil
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12
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Reed JM, Harris DR, Romero LM. Profile repeatability: A new method for evaluating repeatability of individual hormone response profiles. Gen Comp Endocrinol 2019; 270:1-9. [PMID: 30273607 DOI: 10.1016/j.ygcen.2018.09.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/21/2018] [Accepted: 09/25/2018] [Indexed: 01/07/2023]
Abstract
There is broad interest in determining repeatability of individual responses. Current methods calculate repeatability of individual points (initial and/or peak), time to peak value, or a single measure of the integrated total response (area under the curve), rather than the shape of the response profile. Repeatability estimates of response profiles using linear mixed models (LMM) generate an average repeatability for an aggregate of individuals, rather than an estimate of individual repeatability. Here we use a novel ad hoc method to calculate repeatability of individual response profiles and demonstrate the need for a more rigorous assessment protocol. Response profile repeatability has not been defined at the individual level. We do this using a new metric, Profile Repeatability (PR), which incorporates components of variance and the degree to which response profiles cross each other in a time series. Values range from 0 (no repeatability) to 1 (complete repeatability). We created synthetic data to represent a range of apparent time series repeatability, and 20 independent observers visually ranked those data sets by degree of repeatability. We also applied the method to real data on stress responses of European starlings Sturnus vulgaris. We then computed PR scores for the synthetic data and for real data from European starling corticosterone responses over time, and contrast the results to those from LMM. Finally, we assessed the sensitivity of PR to reductions in the number of time points in the corticosterone response, as well as reductions in the number of replicates per individual. We found the average PR scores for a group of individuals to be somewhat robust to reductions in points in the time series; however, the ranks of individuals (PR values relative to one another) could change substantially with reduction in the number of values in a time series. PR showed threshold sensitivity to losing replicate time series between 6 and 4 replicates. Surprisingly, human observers fell into two disparate groups when ranking repeatability of the synthetic data, and the PR score indicated that human observers may underestimate repeatability of data where replicates cross each other. In contrast to the average profile repeatability estimated using LMMs, our approach calculates individual repeatability. From our perspective, LMM does not provide a definitive idea of repeatability at the individual level; in essence, it concludes that suites of time series with low within-individual variance has high repeatability, regardless of replicate trajectories. LMM and PR have non-linear relationships between 0 and 1, but PR has greater discrimination for mid-values of repeatability. Consistent average group repeatability can be associated with substantial differences in individual ranks suggests that estimating individual repeatability is critical. The PR score should be useful in comparing repeatability of any type of nonlinear, including non-monotonic, response profiles over time, which are common in both physiology and behavior, and it demonstrates the specific needs for future improvements of a profile repeatability metric.
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Affiliation(s)
- J Michael Reed
- Department of Biology, Tufts University, Medford, MA, USA.
| | - David R Harris
- Department of Biology, Tufts University, Medford, MA, USA
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Batabyal A, Thaker M. Social coping styles of lizards are reactive and not proactive in urban areas. Gen Comp Endocrinol 2019; 270:67-74. [PMID: 30336119 DOI: 10.1016/j.ygcen.2018.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/04/2018] [Accepted: 10/14/2018] [Indexed: 01/05/2023]
Abstract
Animals engage in social interactions with changes in their behaviour and physiology. Environmental challenges, however, can influence social interactions by adding additional stressors. Here, we investigated the effects of urbanisation on the behaviour and hormonal responses of a tropical lizard species, Psammophilus dorsalis, during social interactions. We recorded behaviour of males from suburban and rural areas during controlled encounters with other males and females. We then measured corticosterone and testosterone levels of individuals at 10 min intervals, from immediately after the social encounter to 30 min later and then at 120 min after the interaction period. We found that differences in social behaviours and subsequent hormone levels were largely driven by habitat, and not social context. Overall, we found that fewer suburban males showed behavioural displays compared to rural males during social encounters. For those that displayed, intensity of aggression was similar across populations, but courtship intensity was lower for suburban males compared to rural males. Suburban males also had significantly elevated levels of corticosterone both under control conditions (no social encounter) and following intra- and intersexual interactions, while rural males retained low levels of corticosterone across contexts. Social interactions were associated with an increase in testosterone levels in all males, but only rural males maintained elevated levels for up to 120 min after interactions with females. Thus, lizards from these suburban and rural populations showed key differences in responsiveness to and recovery from social challenges, a pattern that suggests alternative coping styles ('proactive' vs. 'reactive'). These differences in social coping styles could influence consequences of sexual selection in an urbanised world.
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Affiliation(s)
- Anuradha Batabyal
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India.
| | - Maria Thaker
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India
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Jain-Schlaepfer S, Midwood J, Larsen M, Aarestrup K, King G, Suski C, Cooke S. Relationship of baseline and maximum glucocorticoid concentrations to migration propensity: a field test with wild subadult brown trout (Salmo trutta). CAN J ZOOL 2018. [DOI: 10.1139/cjz-2018-0044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is considerable variation in glucocorticoid (GC) baseline status and stress responses of individuals, yet the cause and consequence of this variation remains ambiguous. Attempts to relate GC levels to fitness and life-history trade-offs have yielded variable results. In this study, we evaluated whether baseline and poststressor GC hormone concentrations predicted migration strategy (i.e., resident or migrant) and successful seaward migration in a partially migrating population of juvenile brown trout (Salmo trutta Linnaeus, 1758). Baseline (N = 99) or poststressor (N = 102) plasma cortisol concentrations were obtained from brown trout and they were tagged with passive integrated transponder (PIT) and released in a natural Danish stream. Subsequently, fish were tracked with PIT reader systems and the stream was resampled for resident individuals. GC levels were not found to be associated with recapture of resident individuals or migration propensity to our first tracking station (S1), but increased baseline (and not poststressor) GC levels were associated with increased passage from S1 to our second tracking station, which anecdotally was an area of high predation or challenge. Our study found no evidence to suggest that cortisol regulates the migration life history in juvenile brown trout, but intermediate increases in baseline GC (and not poststressor GC) levels may favor migration performance.
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Affiliation(s)
- S.M.R. Jain-Schlaepfer
- Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - J.D. Midwood
- Great Lakes Laboratory for Fisheries and Aquatic Science, Canada Centre for Inland Waters, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON L7S 1A1, Canada
| | - M.H. Larsen
- National Institute of Aquatic Resources, Freshwater Fisheries, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
- Danish Centre for Wild Salmon, Brusgårdsvej 15, DK-8960 Randers SØ, Denmark
| | - K. Aarestrup
- National Institute of Aquatic Resources, Freshwater Fisheries, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - G.D. King
- Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - C.D. Suski
- Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - S.J. Cooke
- Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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Kim DS, Chavera C, Gabor CR, Earley RL. Individual variation in ACTH-induced cortisol levels in females of a livebearing fish at different gestational stages. Gen Comp Endocrinol 2018; 261:51-58. [PMID: 29374554 DOI: 10.1016/j.ygcen.2018.01.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/19/2018] [Accepted: 01/22/2018] [Indexed: 01/10/2023]
Abstract
Individuals vary in their baseline levels of stress hormones (predictive homeostasis) and in their stress responses (reactive homeostasis). Variation in normal reactive scope, both predictive and reactive homeostasis, may be important for understanding how endocrine traits respond to selection. Reactive homeostasis is the increase in glucocorticoid (GCs) hormones above baseline. Individuals at different life history stages, such as gestation in females, may show variation in normal reactive scope. We performed an adrenocorticotropic hormone (ACTH) challenge and measured changes in circulating GCs to estimate the reactive scope of female sailfin mollies (Poecilia latipinna) at different gestational states. We measured cortisol, primary GC in teleost fishes, to obtain baseline release rates prior to injection with either ACTH or saline control. Using water-borne hormones, we measured cortisol release rates at four time intervals post-injection. Females were then sacrificed to determine the developmental stage of embryos, if present, and the number of developing embryos or mature ova. We found that ACTH-injected females had significant increases in cortisol releases rates, whereas cortisol release rates of control females did not change during the 4 h post-injection period. We found high repeatability in predictive homeostasis of cortisol and moderate repeatability in reactive homeostasis and a phenotypic correlation between predictive and reactive homeostasis. Gestational state did not affect female predictive or reactive homeostasis. We applied the reactive scope model to P. latipinna and gained a further understanding of how among- and within-individual variation in both predictive and reactive homeostasis are partitioned and how these traits vary under certain life-history conditions.
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Affiliation(s)
- Diana S Kim
- Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, United States.
| | - Christian Chavera
- Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, United States
| | - Caitlin R Gabor
- Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, United States
| | - Ryan L Earley
- Department of Biological Sciences, The University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, United States
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16
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Joshi AM, Narayan EJ, Gramapurohit NP. Interrelationship among annual cycles of sex steroids, corticosterone and body condition in Nyctibatrachus humayuni. Gen Comp Endocrinol 2018; 260:151-160. [PMID: 29339182 DOI: 10.1016/j.ygcen.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/18/2017] [Accepted: 01/11/2018] [Indexed: 11/30/2022]
Abstract
Synergism between extrinsic and intrinsic factors is crucial for the seasonality of reproduction. Environmental factors such as photoperiod and temperature activate the hypothalamus-pituitary-gonadal axis leading to the secretion of steroid hormones that are crucial for reproduction. Sex steroids are not only essential for the maturation of gonads, but also for development of secondary sexual characters in males and reproductive behaviour of both the sexes. In the present study, we quantified the urinary testosterone (UTM) and corticosterone (UCM) metabolites in males and urinary estradiol metabolites (UEM) and UCM in females of Nyctibatrachus humayuni for two consecutive years to determine annual and seasonal variation in the levels of sex steroids, corticosterone and body condition index (BCI). The results show that sex steroids were highest during the breeding season and lowest during the non-breeding season in both the sexes. An increase in UTM and UEM was observed in males and females respectively during the breeding season. Testicular histology showed the presence of all stages of spermatogenesis throughout the year indicating that spermatogenesis is potentially continuous. Ovarian histology showed the presence of vitellogenic follicles only during the breeding season indicating that oogenesis is strictly seasonal. In males, UCM levels were highest during the breeding season, while in females their levels were highest just prior to the breeding season. In males, BCI was highest during the pre-breeding season, declined during the breeding season to increase again during the post-breeding season. In females, BCI was comparable throughout the year. In males, UTM levels were positively correlated with UCM levels but negatively correlated with BCI. Interestingly, UEM, UCM and BCI were not correlated in females. These results indicate that N. humayuni exhibits an associated pattern of reproduction. Quantification of urinary progesterone metabolites (UPM) during the breeding season showed UPM levels were higher in post-spawning females, suggesting the significance of progesterone in ovulation. Further, non-invasive enzyme immunoassay has been successfully standardized in N. humayuni for the quantification of urinary metabolites of steroid hormones.
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Affiliation(s)
- A M Joshi
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India
| | - E J Narayan
- School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - N P Gramapurohit
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India.
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Taff CC, Schoenle LA, Vitousek MN. The repeatability of glucocorticoids: A review and meta-analysis. Gen Comp Endocrinol 2018; 260:136-145. [PMID: 29355531 DOI: 10.1016/j.ygcen.2018.01.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/27/2017] [Accepted: 01/11/2018] [Indexed: 12/17/2022]
Abstract
Glucocorticoids are highly conserved hormones that mediate a suite of responses to changing conditions in vertebrates. Recent work has focused on understanding how selection operates on glucocorticoid secretion in natural populations. Because heritability is rarely estimated and difficult to measure in the wild, many studies report within-individual repeatability as an estimate of stable between individual differences in glucocorticoid secretion. We conducted a systematic review and meta-analysis on estimates of within-individual glucocorticoid repeatability to elucidate general patterns of repeatability, and to test for relationships between covariates and estimates of repeatability. To this end, we collected 203 estimates of within-individual glucocorticoid repeatability drawn from 71 separate studies and 55 species. Overall, we found moderate levels of repeatability (0.29). We also found that repeatability varied by sample type. Long-term measures (e.g., fecal and feather samples) and acute stress-induced plasma glucocorticoids had higher repeatability (long-term: 0.44, stress-induced: 0.38), than baseline glucocorticoid levels (0.18). Repeatability also decreased with increasing time between repeated sampling events. Despite significant overall repeatability, there was substantial heterogeneity in estimates from different studies, suggesting that repeatability of glucocorticoid secretion varies substantially across systems and conditions. We discuss the implications of our results for understanding selection on glucocorticoid traits and suggest that continuing work should focus on evaluating the repeatability of within-individual glucocorticoid reaction norms.
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Affiliation(s)
- Conor C Taff
- Lab of Ornithology and Department of Ecology & Evolutionary Biology, Cornell University, United States.
| | | | - Maren N Vitousek
- Lab of Ornithology and Department of Ecology & Evolutionary Biology, Cornell University, United States
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18
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Schoenemann KL, Bonier F. Repeatability of glucocorticoid hormones in vertebrates: a meta-analysis. PeerJ 2018; 6:e4398. [PMID: 29492340 PMCID: PMC5826989 DOI: 10.7717/peerj.4398] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/31/2018] [Indexed: 01/28/2023] Open
Abstract
We often expect that investigations of the patterns, causes, and consequences of among-individual variation in a trait of interest will reveal how selective pressures or ecological conditions influence that trait. However, many endocrine traits, such as concentrations of glucocorticoid (GC) hormones, exhibit adaptive plasticity and, therefore, do not necessarily respond to these pressures as predicted by among-individual phenotypic correlations. To improve our interpretations of among-individual variation in GC concentrations, we need more information about the repeatability of these traits within individuals. Many studies have already estimated the repeatability of baseline, stress-induced, and integrated GC measures, which provides an opportunity to use meta-analytic techniques to investigate (1) whether GC titers are generally repeatable across taxa, and (2) which biological or methodological factors may impact these estimates. From an intensive search of the literature, we collected 91 GC repeatability estimates from 47 studies. Overall, we found evidence that GC levels are repeatable, with mean repeatability estimates across studies ranging from 0.230 for baseline levels to 0.386 for stress-induced levels. We also noted several factors that predicted the magnitude of these estimates, including taxon, sampling season, and lab technique. Amphibians had significantly higher repeatability in baseline and stress-induced GCs than birds, mammals, reptiles, or bony fish. The repeatability of stress-induced GCs was higher when measured within, rather than across, life history stages. Finally, estimates of repeatability in stress-induced and integrated GC measures tended to be lower when GC concentrations were quantified using commercial kit assays rather than in-house assays. The extent to which among-individual variation in GCs may explain variation in organismal performance or fitness (and thereby inform our understanding of the ecological and evolutionary processes driving that variation) depends on whether measures of GC titers accurately reflect how individuals differ overall. Our findings suggest that while GC titers can reflect some degree of consistent differences among individuals, they frequently may not. We discuss how our findings contribute to interpretations of variation in GCs, and suggest routes for the design and analysis of future research.
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Affiliation(s)
| | - Frances Bonier
- Department of Biology, Queen's University, Kingston, Ontario, Canada
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19
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Passos LF, Garcia G, Young RJ. The tonic immobility test: Do wild and captive golden mantella frogs (Mantella aurantiaca) have the same response? PLoS One 2017; 12:e0181972. [PMID: 28732029 PMCID: PMC5521826 DOI: 10.1371/journal.pone.0181972] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/10/2017] [Indexed: 11/18/2022] Open
Abstract
Adaptations to captivity that reduce fitness are one of many reasons, which explain the low success rate of reintroductions. One way of testing this hypothesis is to compare an important behavioural response in captive and wild members of the same species. Thanatosis, is an anti-predator strategy that reduces the risk of death from predation, which is a common behavioral response in frogs. The study subjects for this investigation were captive and wild populations of Mantella aurantiaca. Thanatosis reaction was measured using the Tonic Immobility (TI) test, a method that consists of placing a frog on its back, restraining it in this position for a short period of time and then releasing it and measuring how much time was spent feigning death. To understand the pattern of reaction time, morphometric data were also collected as body condition can affect the duration of thanatosis. The significantly different TI times found in this study, one captive population with shorter responses, were principally an effect of body condition rather than being a result of rearing environment. However, this does not mean that we can always dismiss the importance of rearing environment in terms of behavioural skills expressed.
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Affiliation(s)
- Luiza Figueiredo Passos
- School of Environment and Life Sciences, Peel Building, University of Salford Manchester, Salford, United Kingdom
- Chester Zoo, Cedar House, Upton by Chester, Chester, United Kingdom
| | - Gerardo Garcia
- Chester Zoo, Cedar House, Upton by Chester, Chester, United Kingdom
| | - Robert John Young
- School of Environment and Life Sciences, Peel Building, University of Salford Manchester, Salford, United Kingdom
- * E-mail:
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20
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Small TW, Bebus SE, Bridge ES, Elderbrock EK, Ferguson SM, Jones BC, Schoech SJ. Stress-responsiveness influences baseline glucocorticoid levels: Revisiting the under 3min sampling rule. Gen Comp Endocrinol 2017; 247:152-165. [PMID: 28189590 DOI: 10.1016/j.ygcen.2017.01.028] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 11/29/2016] [Accepted: 01/28/2017] [Indexed: 12/15/2022]
Abstract
Plasma glucocorticoid (CORT) levels collected within 3min of capture are commonly believed to reflect pre-stressor, baseline CORT levels. Differences in these "baseline" values are often interpreted as reflecting differences in health, or the amount of social and environmental stress recently experienced by an individual. When interpreting "baseline" values it is generally assumed that any effect of capture-and-handling during the initial sampling period is small enough and consistent enough among individuals to not obscure pre-capture differences in CORT levels. However, plasma CORT increases in less than 3min post-capture in many free-living, endothermic species in which timing has been assessed. In addition, the rate of CORT secretion and the maximum level attained (i.e., the degree of stress-responsiveness) during a severe stressor often differs among individuals of the same species. In Florida scrub-jays (Aphelocoma coerulescens), an individual's stress-responsiveness during a 30min post-capture stressor is correlated with CORT levels in samples collected within 1.5min of capture, suggesting there is an intrinsic connection between stress-responsiveness and pre-capture CORT levels. Although differences in stress-responsiveness accounted for just 11% of the variance in these samples, on average, higher stress-responsive jays (top third of individuals) had baseline values twice that of lower stress-responsive jays (bottom third). Further, plasma CORT levels begin to increase around 2min post-capture in this species, but the rate of increase between 2 and 3min differs markedly with CORT increasing more rapidly in jays with higher stress-responsiveness. Together, these data indicate that baseline CORT values can be influenced by an individual's stress response phenotype and the differences due to stress-responsiveness can be exaggerated during sample collection. In some cases, the effects of differences in stress-responsiveness and the increase in CORT during sample collection could obscure, or supersede, differences in pre-capture plasma CORT levels that are caused by extrinsic factors.
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Affiliation(s)
- Thomas W Small
- Department of Biological Sciences, University of Memphis, United States.
| | - Sara E Bebus
- Department of Biological Sciences, University of Memphis, United States
| | - Eli S Bridge
- Oklahoma Biological Survey, University of Oklahoma, United States
| | | | | | - Blake C Jones
- Department of Biological Sciences, University of Memphis, United States
| | - Stephan J Schoech
- Department of Biological Sciences, University of Memphis, United States
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21
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Aspbury AS, Grayson KL, Fantaye S, Nichols I, Myers-Burton M, Ortiz-Mangual X, Gabor CR. The association between male-biased sex ratio and indicators of stress in red-spotted newts. Physiol Behav 2017; 173:156-162. [PMID: 28167148 DOI: 10.1016/j.physbeh.2017.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/28/2016] [Accepted: 02/02/2017] [Indexed: 11/24/2022]
Abstract
In populations with a male-biased operational sex ratio, coercive mating by males can have fitness consequences for females. One component of reduced fitness for females in populations with a male-biased OSR may be greater activation of the stress response, resulting in higher corticosterone release rates (CORT; a glucocorticoid stress hormone in amphibians). We test the hypothesis that a male-biased sex ratio affects female activity and release rates of CORT and testosterone (T) in male and female red-spotted newts (Notophthalmus viridescens). First, we evaluated if chemical cues from a male-biased sex ratio affect activity and CORT release rates in females. We predicted that females exposed to chemical cues of three males would be less active and have higher CORT release rates than those exposed to chemical cues of one male. Second, we measured CORT release rates of red-spotted newts in field enclosures with either a male-biased or a female-biased sex ratio. We predicted that females in the male-biased treatment would have higher CORT and T release rates than those in a female-biased treatment, owing to higher levels of male harassment. We also predicted that males would have higher CORT and T release rates in male-biased treatments due to higher levels of male-male competition. Females were not less active in response to chemical cues from more males over fewer males, but there was a positive relationship between female activity and CORT when they were exposed to the cues of three males. We also found that females, but not males, in the male-biased sex ratio treatment had higher CORT and T release rates than those in the female-biased treatment. Our results support the hypothesis that a male-biased sex ratio leads to a higher stress response, which may underlie the observed decrease in immune function and body condition in previous work exposing female red-spotted newts to a male-biased sex ratio. This study furthers our understanding of the mechanistic basis for costs associated with a male-biased sex ratio in a pond-breeding amphibian.
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Affiliation(s)
- Andrea S Aspbury
- Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666-4684, USA; Mountain Lake Biological Station, 240 Salt Pond Road, Pembroke, VA 24136, USA.
| | - Kristine L Grayson
- Mountain Lake Biological Station, 240 Salt Pond Road, Pembroke, VA 24136, USA; Department of Biology, University of Richmond, 28 Westhampton Way, Richmond, VA, 23173, USA
| | - Selamawit Fantaye
- Mountain Lake Biological Station, 240 Salt Pond Road, Pembroke, VA 24136, USA
| | - Ian Nichols
- Mountain Lake Biological Station, 240 Salt Pond Road, Pembroke, VA 24136, USA
| | | | | | - Caitlin R Gabor
- Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666-4684, USA; Mountain Lake Biological Station, 240 Salt Pond Road, Pembroke, VA 24136, USA
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22
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Madelaire CB, Gomes FR. Breeding under unpredictable conditions: Annual variation in gonadal maturation, energetic reserves and plasma levels of androgens and corticosterone in anurans from the Brazilian semi-arid. Gen Comp Endocrinol 2016; 228:9-16. [PMID: 26808964 DOI: 10.1016/j.ygcen.2016.01.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 01/13/2016] [Accepted: 01/21/2016] [Indexed: 11/20/2022]
Abstract
Anurans living in arid and semi-arid habitats are subjected to unpredictable rain patterns. Consequently, they should be prepared to reproduce at the onset of rain events. We investigated the covariation between calling behavior, testicular maturation, abdominal fat body index (FBI), plasma levels of androgens (T-DHT) and corticosterone (CORT) of males from three species of anurans in the Brazilian semi-arid during the reproductive period and drought. One of these species aestivates during the drought, while the other two species remain foraging. Although the three species display different behavioral strategies during the dry period, they present the same general reproductive patterns. T-DHT levels on the plasma and germinative cyst diameters were higher during the reproductive and breeding period compared to the drought. Additionally, the germinative cysts had all cell stages including sperm bundles during the dry season, however, it was only during the breeding event that free spermatozoa were found in the cyst lumen. These results suggest that these species present the reproductive pattern typical of desert anurans, consisting of opportunistic breeders that reproduce when triggered by a rain stimulus. Rhinella jimi and Pleurodema diplolister had higher CORT when males were calling. Moreover, Rhinella granulosa and P. diplolister showed lower FBI during breeding event, when males were calling. The high levels of CORT and lower FBI during reproductive period are associated, indicating that CORT modulates the recruitment of energy stores to prepare and maintain reproduction, particularly the expensive calling effort.
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Affiliation(s)
- Carla Bonetti Madelaire
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav. 14, n° 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
| | - Fernando Ribeiro Gomes
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav. 14, n° 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
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Harms NJ, Legagneux P, Gilchrist HG, Bêty J, Love OP, Forbes MR, Bortolotti GR, Soos C. Feather corticosterone reveals effect of moulting conditions in the autumn on subsequent reproductive output and survival in an Arctic migratory bird. Proc Biol Sci 2016; 282:20142085. [PMID: 25540279 DOI: 10.1098/rspb.2014.2085] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
For birds, unpredictable environments during the energetically stressful times of moulting and breeding are expected to have negative fitness effects. Detecting those effects however, might be difficult if individuals modulate their physiology and/or behaviours in ways to minimize short-term fitness costs. Corticosterone in feathers (CORTf) is thought to provide information on total baseline and stress-induced CORT levels at moulting and is an integrated measure of hypothalamic-pituitary-adrenal activity during the time feathers are grown. We predicted that CORTf levels in northern common eider females would relate to subsequent body condition, reproductive success and survival, in a population of eiders nesting in the eastern Canadian Arctic during a capricious period marked by annual avian cholera outbreaks. We collected CORTf data from feathers grown during previous moult in autumn and data on phenology of subsequent reproduction and survival for 242 eider females over 5 years. Using path analyses, we detected a direct relationship between CORTf and arrival date and body condition the following year. CORTf also had negative indirect relationships with both eider reproductive success and survival of eiders during an avian cholera outbreak. This indirect effect was dramatic with a reduction of approximately 30% in subsequent survival of eiders during an avian cholera outbreak when mean CORTf increased by 1 standard deviation. This study highlights the importance of events or processes occurring during moult on subsequent expression of life-history traits and relation to individual fitness, and shows that information from non-destructive sampling of individuals can track carry-over effects across seasons.
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Affiliation(s)
- N Jane Harms
- Department of Veterinary Pathology, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5B4
| | - Pierre Legagneux
- Département de biologie et Centre d'études nordiques, Université du Québec à Rimouski, 300 Allée des Ursulines Rimouski, Quebec, Canada G5L 3A1
| | - H Grant Gilchrist
- National Wildlife Research Centre, Environment Canada, Ottawa, Ontario, Canada K1A 0H3
| | - Joël Bêty
- Département de biologie et Centre d'études nordiques, Université du Québec à Rimouski, 300 Allée des Ursulines Rimouski, Quebec, Canada G5L 3A1
| | - Oliver P Love
- Department of Biological Sciences, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, Canada N9B 3P4
| | - Mark R Forbes
- Department of Biology, Carleton University, Ottawa, Ontario, Canada K1A 0H3
| | - Gary R Bortolotti
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, Canada S7N 5E2
| | - Catherine Soos
- Environment Canada, 115 Perimeter Road, Saskatoon, Saskatchewan, Canada S7N 0X4
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Narayan EJ, Gramapurohit NP. Sexual dimorphism in baseline urinary corticosterone metabolites and their association with body-condition indices in a peri-urban population of the common Asian toad (Duttaphrynus melanostictus). Comp Biochem Physiol A Mol Integr Physiol 2015; 191:174-179. [PMID: 26478192 DOI: 10.1016/j.cbpa.2015.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/02/2015] [Accepted: 10/11/2015] [Indexed: 11/29/2022]
Abstract
Field endocrinology research through the quantification of glucocorticoids or stress hormones in free-living wildlife is crucial for assessing their physiological responses towards pervasive environmental changes. Urinary corticosterone metabolite (UCM) enzyme-immunoassay (EIA) has been validated for numerous amphibian species as a non-invasive measure of physiological stress. Body-condition indices (BCIs) have also been widely used in amphibians as an indirect measure of animal health. Field endocrinology research on amphibian species in Asia is limited. In this study, we validated a UCM EIA in a peri-urban sub-population of the common Asian toad (Duttaphrynus melanostictus) in Pune, Maharashtra, India. We determined the baseline levels of UCMs in male (n=39) and female (n=19) toads. Secondly, we used a standard capture handling protocol to quantify changes in UCMs during short-term captivity. We also determined BCIs in the male and female toads using Fulton's index (K) and residual condition index (RCI). The results showed that mean baseline levels of UCMs were significantly higher in male toads than in females. There was no significant change in mean levels of UCMs of males and females between capture and captivity (0-12h). This highlights plausible habituation of the species to the peri-urban environment. Associations between UCMs with BCIs (K and R) were positive in male toads but negative in females. In conclusion, our UCMs EIA can be applied with BCIs to assess health of the Asian toads. We also suggest that direct fitness parameters such as sperm and oocyte quality, reproductive ecology and immunocompetence measurements should be applied in combination with these conservation physiology tools to quantify the fitness consequences of pervasive environmental changes on native amphibians.
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Affiliation(s)
- Edward J Narayan
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia.
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25
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Small TW, Schoech SJ. Sex differences in the long-term repeatability of the acute stress response in long-lived, free-living Florida scrub-jays (Aphelocoma coerulescens). J Comp Physiol B 2014; 185:119-33. [DOI: 10.1007/s00360-014-0866-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/25/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
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26
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Reedy AM, Edwards A, Pendlebury C, Murdaugh L, Avery R, Seidenberg J, Aspbury AS, Gabor CR. An acute increase in the stress hormone corticosterone is associated with mating behavior in both male and female red-spotted newts, Notophthalmus viridescens. Gen Comp Endocrinol 2014; 208:57-63. [PMID: 25157790 DOI: 10.1016/j.ygcen.2014.08.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/30/2014] [Accepted: 08/14/2014] [Indexed: 11/26/2022]
Abstract
Hormones play key, functional roles in mediating the tradeoff between survival and reproduction. Glucocorticoid hormones can inhibit reproduction and improve chances of survival during periods of stress. However, glucocorticoid hormones are, at times, also associated with successfully engaging in energetically costly courtship and mating behaviors. Corticosterone (CORT), a primary glucocorticoid hormone in amphibians, reptiles and birds, may be important in activating or sustaining energetically costly mating behaviors. We used a non-invasive, water-borne hormone assay to measure CORT release rates of male and female red-spotted newts (Notophthalmus viridescens) collected when either engaged in amplexus or when not engaged in amplexus. Because amplexus is energetically costly for males, we predicted that males would have higher CORT release rates than females. We also predicted that females in amplexus would have elevated CORT release rates because the restraint of amplexus prevents foraging and breathing and may be costly. Here we show that an acute increase in CORT is associated with amplexus behavior in both male and female red-spotted newts. Additionally we demonstrate that males have higher overall CORT release rates both in and out of amplexus than do females. Our results support the hypothesis that glucocorticoid hormones are associated with energetically costly courtship and mating behaviors for both sexes.
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Affiliation(s)
- Aaron M Reedy
- Department of Biology, University of Virginia, Charlottesville, VA 22902, USA; Mountain Lake Biological Station, Pembroke, VA 24136, USA.
| | - Alex Edwards
- Department of Biology, University of Virginia, Charlottesville, VA 22902, USA; Mountain Lake Biological Station, Pembroke, VA 24136, USA
| | - Chloe Pendlebury
- Department of Biology, University of Virginia, Charlottesville, VA 22902, USA; Mountain Lake Biological Station, Pembroke, VA 24136, USA
| | - Laura Murdaugh
- Mountain Lake Biological Station, Pembroke, VA 24136, USA; Indiana University of Pennsylvania, Indiana, PA 15705, USA
| | - Ryan Avery
- Department of Biology, University of Virginia, Charlottesville, VA 22902, USA; Mountain Lake Biological Station, Pembroke, VA 24136, USA
| | | | - Andrea S Aspbury
- Mountain Lake Biological Station, Pembroke, VA 24136, USA; Department of Biology, Texas State University-San Marcos, TX 78666-4684, USA
| | - Caitlin R Gabor
- Mountain Lake Biological Station, Pembroke, VA 24136, USA; Department of Biology, Texas State University-San Marcos, TX 78666-4684, USA
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Grace JK, Anderson DJ. Corticosterone stress response shows long-term repeatability and links to personality in free-living Nazca boobies. Gen Comp Endocrinol 2014; 208:39-48. [PMID: 25220912 DOI: 10.1016/j.ygcen.2014.08.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/26/2014] [Accepted: 08/30/2014] [Indexed: 11/19/2022]
Abstract
The concept of "coping styles", or consistently different responses to stressors, is of broad interest in behavioral ecology and biomedicine. Two critical predictions of this concept are individual consistency of neurophysiological and behavioral responses (relative to population variability) and a negative relationship between aggression/proactivity and hypothalamic-pituitary-adrenal axis reactivity. Recent studies failed to provide strong support for these predictions, especially outside of strictly controlled conditions, and long-term measures to test the first prediction are rare. Here, we demonstrate individual repeatability across 2-3years of maximum circulating corticosterone concentration [CORT] and area under the [CORT] response curve (AUCI) during a standard capture-restraint test in wild, free-living adult Nazca boobies (Sula granti). We also show that the stress response predicts the personality traits aggression and anxiety in these birds (measured in the wild); however, the strength of these results was weak. Maximum [CORT] and AUCI showed higher repeatability between years than baseline [CORT]. After controlling breeding status, sex, mass, date sampled, and their interactions, baseline [CORT] was most closely related to personality traits, followed by AUCI, and then maximum [CORT]. The direction of these relationships depended on whether the testing context was social or non-social. [CORT] parameters had little to no relationship with cross-context plasticity in personality traits. Our results generally affirm two critical predictions of coping styles, but match the emerging trend that these relationships are weak in the wild, and may depend on testing context.
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Affiliation(s)
- Jacquelyn K Grace
- Dept. of Biology, Wake Forest University, Winston-Salem, NC 27106, USA.
| | - David J Anderson
- Dept. of Biology, Wake Forest University, Winston-Salem, NC 27106, USA
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Narayan EJ, Hero JM. Repeated thermal stressor causes chronic elevation of baseline corticosterone and suppresses the physiological endocrine sensitivity to acute stressor in the cane toad (Rhinella marina). J Therm Biol 2014; 41:72-6. [DOI: 10.1016/j.jtherbio.2014.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 02/08/2014] [Accepted: 02/10/2014] [Indexed: 11/29/2022]
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Narayan EJ, Hero JM. Acute thermal stressor increases glucocorticoid response but minimizes testosterone and locomotor performance in the cane toad (Rhinella marina). PLoS One 2014; 9:e92090. [PMID: 24643017 PMCID: PMC3958476 DOI: 10.1371/journal.pone.0092090] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/19/2014] [Indexed: 11/18/2022] Open
Abstract
Climatic warming is a global problem and acute thermal stressor in particular could be considered as a major stressor for wildlife. Cane toads (Rhinella marina) have expanded their range into warmer regions of Australia and they provide a suitable model species to study the sub-lethal impacts of thermal stressor on the endocrine physiology of amphibians. Presently, there is no information to show that exposure to an acute thermal stressor could initiate a physiological stress (glucocorticoid) response and secondly, the possible effects on reproductive hormones and performance. Answering these questions is important for understanding the impacts of extreme temperature on amphibians. In this study, we experimented on cane toads from Queensland, Australia by acclimating them to mildly warm temperature (25°C) and then exposing to acute temperature treatments of 30°, 35° or 40°C (hypothetical acute thermal stressors). We measured acute changes in the stress hormone corticosterone and the reproductive hormone testosterone using standard capture and handling protocol and quantified the metabolites of both hormones non-invasively using urinary enzyme-immunoassays. Furthermore, we measured performance trait (i.e. righting response score) in the control acclimated and the three treatment groups. Corticosterone stress responses increased in all toads during exposure to an acute thermal stressor. Furthermore, exposure to a thermal stressor also decreased testosterone levels in all toads. The duration of the righting response (seconds) was longer for toads that were exposed to 40°C than to 30°, 35° or 25°C. The increased corticosterone stress response with increased intensity of the acute thermal stressor suggests that the toads perceived this treatment as a stressor. Furthermore, the results also highlight a potential trade-off with performance and reproductive hormones. Ultimately, exposure acute thermal stressors due to climatic variability could impact amphibians at multiple eco-physiological levels through impacts on endocrine physiology, performance and potentially fitness traits (e.g. reproductive output).
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Affiliation(s)
- Edward J Narayan
- Environmental Futures Research Institute, School of Environment, Griffith University, Gold Coast Campus, Australia
| | - Jean-Marc Hero
- Environmental Futures Research Institute, School of Environment, Griffith University, Gold Coast Campus, Australia
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Narayan EJ, Cockrem JF, Hero JM. Sight of a predator induces a corticosterone stress response and generates fear in an amphibian. PLoS One 2013; 8:e73564. [PMID: 24009756 PMCID: PMC3757005 DOI: 10.1371/journal.pone.0073564] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/20/2013] [Indexed: 11/19/2022] Open
Abstract
Amphibians, like other animals, generate corticosterone or cortisol glucocorticoid responses to stimuli perceived to be threatening. It is generally assumed that the corticosterone response of animals to capture and handling reflects the corticosterone response to stimuli such as the sight of a predator that are thought to be natural stressors. Fijian ground frogs (Platymantisvitiana) are preyed upon by the introduced cane toads (Rhinellamarina), and we used ground frogs to test the hypothesis that the sight of a predator will induce a corticosterone stress response in an amphibian. Urinary corticosterone metabolite concentrations increased in male ground frogs exposed to the sight of a toad for 1, 3 or 6 h, whereas corticosterone did not change in frogs exposed to another male ground frog, a ball, or when no stimulus was present in the test compartment. The frogs exposed to a toad initially moved towards the stimulus then moved away, whereas frogs exposed to another frog moved towards the test frog and remained closer to the frog than at the start of the test. Tonic immobility (TI) was measured as an index of fearfulness immediately after the test exposure of the frogs to a stimulus. The duration of TI was longer in frogs exposed to a toad than to another frog or to a ball. The results provide novel evidence that the sight of a predator can induce a corticosterone response and lead to increased fearfulness in amphibians. In addition, they show that endemic frogs can recognise an introduced predator as a threat.
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Affiliation(s)
- Edward J Narayan
- Environmental Futures Centre, School of Environment, Griffith University, Gold Coast Campus, Southport, Australia.
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Narayan EJ, Hero JM. Repeatability of Baseline Corticosterone and Acute Stress Responses to Capture, and Patterns of Reproductive Hormones in Vitellogenic and Non-Vitellogenic Female Fijian Ground Frog (Platymantis vitiana). ACTA ACUST UNITED AC 2013; 319:471-81. [DOI: 10.1002/jez.1810] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/13/2013] [Accepted: 06/03/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Edward J. Narayan
- Environmental Futures Centre; School of Environment; Griffith University; Gold Coast Campus; Gold Coast, QLD; Australia
| | - Jean-Marc Hero
- Environmental Futures Centre; School of Environment; Griffith University; Gold Coast Campus; Gold Coast, QLD; Australia
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Narayan EJ. Non-invasive reproductive and stress endocrinology in amphibian conservation physiology. CONSERVATION PHYSIOLOGY 2013; 1:cot011. [PMID: 27293595 PMCID: PMC4806611 DOI: 10.1093/conphys/cot011] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 04/18/2013] [Accepted: 04/18/2013] [Indexed: 05/03/2023]
Abstract
Non-invasive endocrinology utilizes non-invasive biological samples (such as faeces, urine, hair, aquatic media, and saliva) for the quantification of hormones in wildlife. Urinary-based enzyme immunoassay (EIA) and radio-immunoassay have enabled the rapid quantification of reproductive and stress hormones in amphibians (Anura: Amphibia). With minimal disturbance, these methods can be used to assess the ovarian and testicular endocrine functions as well as physiological stress in captive and free-living populations. Non-invasive endocrine monitoring has therefore greatly advanced our knowledge of the functioning of the stress endocrine system (the hypothalamo-pituitary-interrenal axis) and the reproductive endocrine system (the hypothalamo-pituitary-gonadal axis) in the amphibian physiological stress response, reproductive ecology, health and welfare, and survival. Biological (physiological) validation is necessary for obtaining the excretory lag time of hormone metabolites. Urinary-based EIA for the major reproductive hormones, estradiol and progesterone in females and testosterone in males, can be used to track the reproductive hormone profiles in relationship to reproductive behaviour and environmental data in free-living anurans. Urinary-based corticosterone metabolite EIA can be used to assess the sublethal impacts of biological stressors (such as invasive species and pathogenic diseases) as well as anthropogenic induced environmental stressors (e.g. extreme temperatures) on free-living populations. Non-invasive endocrine methods can also assist in the diagnosis of success or failure of captive breeding programmes by measuring the longitudinal patterns of changes in reproductive hormones and corticosterone within captive anurans and comparing the endocrine profiles with health records and reproductive behaviour. This review paper focuses on the reproductive and the stress endocrinology of anurans and demonstrates the uses of non-invasive endocrinology for advancing amphibian conservation physiology. It also provides key technical considerations for future research that will increase the accuracy and reliability of the data and the value of non-invasive endocrinology within the conceptual framework of conservation physiology.
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Affiliation(s)
- E. J. Narayan
- Corresponding author: Environmental Futures Centre, School of Environment, Griffith University, Gold Coast Campus, QLD 4222, Australia. Tel: +61 (0)4 0169 7287. ;
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