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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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Mohring B, Öst M, Jaatinen K, Parenteau C, Pallud M, Angelier F. Parenting in a changing environment: A long-term study of prolactin, parental effort and reproductive success in common eiders. Gen Comp Endocrinol 2024; 357:114574. [PMID: 38936675 DOI: 10.1016/j.ygcen.2024.114574] [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: 10/23/2023] [Revised: 06/15/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024]
Abstract
Parental care is regulated by multiple endocrine mechanisms. Among these hormones, prolactin (PRL) is involved in the expression of parental behaviors. Despite the consensus that PRL mediates variation in parental effort with age and body condition, its role in the adjustment of parental effort to fluctuating environmental conditions, including changing predation pressure, still awaits further investigation. To shed light on this knowledge gap, we relied on a long-term monitoring of female common eiders Somateria mollissima (n = 1277 breeding attempts, 2012-2022) incubating under fluctuating predation risk to investigate the link between baseline PRL levels and female minimum age, body condition, clutch size, environmental parameters (predation pressure, climate, nest microhabitat) and hatching success. We predicted that PRL would be higher in older females, those in better condition or incubating larger clutches. We also predicted that females would reduce parental effort when nesting under challenging environmental conditions (high predation pressure or poor climatic conditions), translated into reduced baseline PRL levels. We also explored how variation in PRL levels, female characteristics and environmental parameters were related to hatching success. Following our predictions, PRL levels were positively associated with body condition and female age (before showing a senescent decline in the oldest breeders). However, we did not observe any population-level or individual-level reduction in PRL levels in response to increasing predation pressure. Population-level baseline PRL levels instead increased over the study period, coincident with rising predation threat, but also increasing female body condition and age. While we did not provide evidence for a direct association between baseline PRL levels and predation risk, our results support the idea that elevated baseline PRL levels promote hatching success under internal constraints (in young, inexperienced, breeders or those incubating a large clutch) or constraining environmental conditions (during years of high predation pressure or poor climatic and foraging conditions). Finally, the low repeatability of baseline PRL levels and high interannual variability highlight considerable within-individual flexibility in baseline PRL levels. Further research should explore flexibility in parental effort to changing environmental conditions, focusing on both baseline and stress-induced PRL levels.
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Affiliation(s)
- Bertille Mohring
- Environmental and Marine Biology, Åbo Akademi University, 20500 Turku, Finland; Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS - La Rochelle Université, 79360 Villiers-en-Bois, France; School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom.
| | - Markus Öst
- Environmental and Marine Biology, Åbo Akademi University, 20500 Turku, Finland; Novia University of Applied Sciences, 10600 Ekenäs, Finland
| | - Kim Jaatinen
- Finnish Environment Institute, 00790 Helsinki, Finland; Tvärminne Zoological Station, University of Helsinki, 10900 Hanko, Finland
| | - Charline Parenteau
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS - La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Marie Pallud
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS - La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS - La Rochelle Université, 79360 Villiers-en-Bois, France
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McKinnon RA, Hawkshaw K, Hedlin E, Nakagawa S, Mathot KJ. Peregrine falcons shift mean and variance in provisioning in response to increasing brood demand. Behav Ecol 2024; 35:arad103. [PMID: 38144905 PMCID: PMC10746350 DOI: 10.1093/beheco/arad103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 10/11/2023] [Accepted: 11/28/2023] [Indexed: 12/26/2023] Open
Abstract
The hierarchical model of provisioning posits that parents employ a strategic, sequential use of three provisioning tactics as offspring demand increases (e.g., due to increasing brood size and age). Namely, increasing delivery rate (reducing intervals between provisioning visits), expanding provisioned diet breadth, and adopting variance-sensitive provisioning. We evaluated this model in an Arctic breeding population of Peregrine falcons (Falco peregrinus tundrius) by analyzing changes in inter-visit-intervals (IVIs) and residual variance in IVIs across 7 study years. Data were collected using motion-sensitive nest camera images and analyzed using Bayesian mixed effect models. We found strong support for a decrease in IVIs (i.e., increase in delivery rates) between provisioning visits and an increase in residual variance in IVIs with increasing nestling age, consistent with the notion that peregrines shift to variance-prone provisioning strategies with increasing nestling demand. However, support for predictions made based on the hierarchical model of tactics for coping with increased brood demand was equivocal as we did not find evidence in support of expected covariances between random effects (i.e., between IVI to an average sized brood (intercept), change in IVI with brood demand (slope) or variance in IVI). Overall, our study provides important biological insights into how parents cope with increased brood demand.
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Affiliation(s)
- Rebekah A McKinnon
- Department of Biological Sciences, University of Alberta, CW 405, Biological Sciences Building, Edmonton, AB T6G 2E9, Canada
- Nunavut Wildlife Cooperative Research Unit, Universiy of Alberta, CW 405, Biological Sciences Building, Edmonton, AB T6G 2E9,Canada
| | - Kevin Hawkshaw
- Nunavut Wildlife Cooperative Research Unit, Universiy of Alberta, CW 405, Biological Sciences Building, Edmonton, AB T6G 2E9,Canada
- Department of Renewable Resources, University of Alberta, GSB 751, Edmonton, AB T6G 0N4, Canada
| | - Erik Hedlin
- Department of Renewable Resources, University of Alberta, GSB 751, Edmonton, AB T6G 0N4, Canada
| | - Shinichi Nakagawa
- Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, Biological Sciences North, University of New South Wales, Sydney, NSW 2052, Australia
| | - Kimberley J Mathot
- Department of Biological Sciences, University of Alberta, CW 405, Biological Sciences Building, Edmonton, AB T6G 2E9, Canada
- Canada Research Chair in Integrative Ecology, Department of Biological Sciences, CW 405, Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9, Canada
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Harris S, Scioscia G, Raya Rey A. The influence of tourist visitation on the heterophyl to lymphocyte ratios and trophic values of Magellanic penguins ( Spheniscus magellanicus) at Martillo Island, Argentina. CONSERVATION PHYSIOLOGY 2023; 11:coad063. [PMID: 38053739 PMCID: PMC10694407 DOI: 10.1093/conphys/coad063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 07/18/2023] [Accepted: 08/14/2023] [Indexed: 12/07/2023]
Abstract
Wildlife tourism is increasing worldwide and monitoring the impact of tourism on wild populations is of the utmost importance for species conservation. The Magellanic penguin Spheniscus magellanicus colony at Martillo Island, Argentina, was studied in the 2016-2020 breeding seasons. In all seasons, adults and chicks belonged to: (i) an area close to or within the tourist trail or (ii) an area far from the tourist trail and out of sight of the tourists. Blood samples were taken for carbon and nitrogen stable isotope composition, in order to estimate trophic niches, and for smears that were made in situ and were then stained in the laboratory where leucocyte counts and differentiation were made under optical microscope. Heterophil to lymphocyte ratios were used as proxies of stress. Repeated sampling showed individual stress levels reduced while wintering. In 2017, stress levels and trophic values were lower than 2018 for the same individuals. Trophic levels did not differ between tourism and no tourism areas within each season, and differed between 2017 and the remaining seasons, indicating a possible diet shift that year. Stress levels were higher for the tourism area than the no tourism area for adults and chicks in all years except for 2020, when stress levels in the tourism area were lower and similar to the no tourism area that year and previous years. Vessel transit within the Beagle Channel and tourist visitation to the penguin colony was greatly reduced in 2020 due to the Covid-19 pandemic. A combination of internal characteristics and external factors may be affecting the stress physiology of individuals. Therefore, future research should include sampling of multiple aspects of penguin physiology, behaviour and environmental context in order to evaluate each effect on Magellanic penguin stress and, ultimately, inform the conservation of this iconic species in time.
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Affiliation(s)
- Sabrina Harris
- Laboratorio de Ecología y Conservación de Vida silvestre, Centro Austral de Investigaciones Científicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Houssay 200 (9410) Ushuaia, Tierra del Fuego, Argentina
- Wildlife Conservation Society representación Argentina, Amenábar 1595 piso 2 oficina 19 (1426) CABA, Buenos Aires, Argentina
| | - Gabriela Scioscia
- Laboratorio de Ecología y Conservación de Vida silvestre, Centro Austral de Investigaciones Científicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Houssay 200 (9410) Ushuaia, Tierra del Fuego, Argentina
| | - Andrea Raya Rey
- Laboratorio de Ecología y Conservación de Vida silvestre, Centro Austral de Investigaciones Científicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Houssay 200 (9410) Ushuaia, Tierra del Fuego, Argentina
- Wildlife Conservation Society representación Argentina, Amenábar 1595 piso 2 oficina 19 (1426) CABA, Buenos Aires, Argentina
- Instituto de Ciencias Polares, Ambiente y Recursos Naturales (ICPA), Universidad de Tierra del Fuego (UNTDF), Walanika 250 (9410) Ushuaia, Tierra del Fuego, Argentina
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Newediuk L, Bath DR. Meta-analysis reveals between-population differences affect the link between glucocorticoids and population health. CONSERVATION PHYSIOLOGY 2023; 11:coad005. [PMID: 36845329 PMCID: PMC9945071 DOI: 10.1093/conphys/coad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Glucocorticoids are a popular tool for monitoring health of animal populations because they can increase with environmental stressors and can indicate chronic stress. However, individual responses to stressors create variation in the glucocorticoid-fitness relationship within populations. The inconsistency in this relationship calls into question the widespread use of glucocorticoids in conservation. We investigated the sources of variation in the glucocorticoid-fitness relationship by conducting a meta-analysis across a diverse set of species exposed to conservation-relevant stressors. We first quantified the extent to which studies inferred population health from glucocorticoids without first validating the glucocorticoid-fitness relationship in their own populations. We also tested whether population-level information like life history stage, sex and species longevity influenced the relationship between glucocorticoids and fitness. Finally, we tested for a universally consistent relationship between glucocorticoids and fitness across studies. We found more than half of peer-reviewed studies published between 2008 and 2022 inferred population health solely based on glucocorticoid levels. While life history stage explained some variation in the relationship between glucocorticoids and fitness, we found no consistent relationship between them. Much of the variation in the relationship could be the result of idiosyncratic characteristics of declining populations, such as unstable demographic structure, that coincided with large amounts of variation in glucocorticoid production. We suggest that conservation biologists capitalize on this variation in glucocorticoid production by declining populations by using the variance in glucocorticoid production as an early warning for declines in population health.
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Affiliation(s)
- Levi Newediuk
- Corresponding author: Department of Biology, Memorial University, 45 Arctic Avenue, St. John's, Newfoundland A1B 3X9, Canada.
| | - Devon R Bath
- Department of Ocean Sciences, Memorial University, 0 Marine Lab Road, St. John's, Newfoundland A1C 5S7, Canada
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Farrar VS, Morales Gallardo J, Calisi RM. Prior parental experience attenuates hormonal stress responses and alters hippocampal glucocorticoid receptors in biparental rock doves. J Exp Biol 2022; 225:285344. [PMID: 36448917 DOI: 10.1242/jeb.244820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/18/2022] [Indexed: 12/02/2022]
Abstract
In the face of challenges, animals must balance investments in reproductive effort versus their own survival. Physiologically, this trade-off may be mediated by glucocorticoid release by the hypothalamic-pituitary-adrenal axis and prolactin release from the pituitary to maintain parental care. The degree to which animals react to and recover from stressors likely affects maintenance of parental behavior and, ultimately, fitness. However, less is known about how gaining parental experience may alter hormonal stress responses and their underlying neuroendocrine mechanisms. To address this gap, we measured the corticosterone (CORT) and prolactin (PRL) stress response in individuals of both sexes of the biparental rock dove (Columba livia) that had never raised chicks versus birds that had fledged at least one chick. We measured both CORT and PRL at baseline and after an acute stressor (30 min restraint). We also measured negative feedback ability by administering dexamethasone, a synthetic glucocorticoid that suppresses CORT release, and measured CORT and PRL after 60 min. All hormones were measured when birds were not actively nesting to assess whether effects of parental experience extend beyond the breeding bout. Experienced birds had lower stress-induced and negative-feedback CORT, and higher stress-induced PRL than inexperienced birds. In a separate experiment, we measured glucocorticoid receptor subtype expression in the hippocampus, a key site of negative feedback regulation. Experienced birds showed higher glucocorticoid receptor expression than inexperienced controls, which may mediate their ability to attenuate CORT release. Together, these results shed light on potential mechanisms by which gaining experience may improve parental performance and fitness.
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Affiliation(s)
- Victoria S Farrar
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, USA
| | - Jaime Morales Gallardo
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, USA
| | - Rebecca M Calisi
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, USA
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Ledwoń M, Flis A, Banach A, Neubauer G, Angelier F. Baseline and stress-induced prolactin and corticosterone concentrations in a species with female offspring desertion - The case of Whiskered Tern Chlidonias hybrida. Gen Comp Endocrinol 2022; 317:113943. [PMID: 34800441 DOI: 10.1016/j.ygcen.2021.113943] [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: 05/07/2021] [Revised: 09/17/2021] [Accepted: 11/13/2021] [Indexed: 11/20/2022]
Abstract
To understand the proximate mechanisms regulating brood desertion, we studied hormonal and behavioural stress responses during the chick-rearing period in adult Whiskered Terns (Chlidonias hybrida), a socially monogamous, semi-precocial species with prolonged post-fledging parental care. In contrast to males, almost all females of this species desert during the chick-rearing and post-fledging periods. Because of the expected link between corticosterone, prolactin and parental investment, we hypothesized that males and females should differ in circulating prolactin and corticosterone concentrations. Baseline hormone concentrations did not differ between males and females. In both sexes, prolactin and corticosterone concentrations decreased and increased in response to acute stress (30 min after capture), respectively. Baseline and stress-induced prolactin concentrations decreased significantly in both sexes with advancing brood age. As expected, males had significantly higher stress-induced prolactin concentrations than females. None of the nine males released after being held in captivity for 24 h deserted, whereas four (29%) of the 14 females kept in captivity for 24 h did so. Altogether, these results suggest that higher prolactin concentrations may be involved in the maintenance of parental care under stress. However, there was no statistically significant difference in stress-induced hormone levels between males, females that deserted and those that returned to the nest after prolonged stress (24 h). Our data indicate that males are probably more resistant to stress as regards the continuation of parental care. The pattern of male and female behavioural and hormonal responses to stress partially predicts their behaviour in terms of natural desertion.
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Affiliation(s)
- Mateusz Ledwoń
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland.
| | - Adam Flis
- Institute of Nature Conservation, Polish Academy of Sciences, Adama Mickiewicza 33, 31-120 Kraków, Poland
| | - Agata Banach
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland
| | - Grzegorz Neubauer
- Laboratory of Forest Biology, Wrocław University, ul. Sienkiewicza 21, 50-335 Wrocław, Poland
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS- la Rochelle Université, Villiers en Bois, France
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Mohring B, Angelier F, Jaatinen K, Parenteau C, Öst M. Parental Investment Under Predation Threat in Incubating Common Eiders (Somateria mollissima): A Hormonal Perspective. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.637561] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Predation risk affects the costs and benefits of prey life-history decisions. Predation threat is often higher during reproduction, especially in conspicuous colonial breeders. Therefore, predation risk may increase the survival cost of breeding, and reduce parental investment. The impact of predation risk on avian parental investment decisions may be hormonally mediated by prolactin and corticosterone, making them ideal tools for studying the trade-offs involved. Prolactin is thought to promote parental care and commitment in birds. Corticosterone is involved in allostasis and may either mediate reduced parental investment (corticosterone-fitness hypothesis), or promote parental investment through a reallocation of resources (corticosterone-adaptation hypothesis). Here, we used these hormonal proxies of incubation commitment to examine the impact of predation risk on reproduction in common eiders (Somateria mollissima) breeding in the Baltic Sea. This eider population is subject to high but spatially and temporally variable predation pressure on adults (mainly by the white-tailed eagle Haliaeetus albicilla and introduced mammalian predators) and nests (by the adult predators and exclusive egg predators such as hooded crows Corvus cornix). We investigated baseline hormonal levels and hatching success as a function of individual quality attributes (breeding experience, female and duckling body condition), reproductive investment (clutch weight), and predation risk. We expected individuals nesting in riskier environments (i.e., on islands where predation on adults or nests is higher, or in less concealed nests) to reduce their parental investment in incubation, reflected in lower baseline prolactin levels and either higher (corticosterone-fitness hypothesis) or lower (corticosterone-adaptation hypothesis) baseline corticosterone levels. Contrary to our predictions, prolactin levels showed a positive correlation with nest predation risk. The unexpected positive relationship could result from the selective disappearance of low-quality females (presumably having low prolactin levels) from risky sites. Supporting this notion, female body condition and hatching success were positively correlated with predation risk on females, and baseline prolactin concentrations were positively correlated with duckling body condition, a proxy of maternal quality. In line with the corticosterone-adaptation hypothesis, baseline corticosterone levels increased with reproductive investment, and were negatively associated with nest predation risk. Hatching success was lower on islands where nest predation risk was higher, consistent with the idea of reduced reproductive investment under increased threat. Long-term individual-based studies are now needed to distinguish selection processes occurring at the population scale from individually plastic parental investment in relation to individual quality and variable predation risk.
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Names GR, Krause JS, Schultz EM, Angelier F, Parenteau C, Ribout C, Hahn TP, Wingfield JC. Relationships between avian malaria resilience and corticosterone, testosterone and prolactin in a Hawaiian songbird. Gen Comp Endocrinol 2021; 308:113784. [PMID: 33862049 DOI: 10.1016/j.ygcen.2021.113784] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/23/2021] [Accepted: 04/09/2021] [Indexed: 01/19/2023]
Abstract
Glucocorticoids, androgens, and prolactin regulate metabolism and reproduction, but they also play critical roles in immunomodulation. Since the introduction of avian malaria to Hawaii a century ago, low elevation populations of the Hawaii Amakihi (Chlorodrepanis virens) that have experienced strong selection by avian malaria have evolved increased resilience (the ability to recover from infection), while high elevation populations that have undergone weak selection remain less resilient. We investigated how variation in malaria selection has affected corticosterone, testosterone, and prolactin hormone levels in Amakihi during the breeding season. We predicted that baseline corticosterone and testosterone (which have immunosuppressive functions) would be reduced in low elevation and malaria-infected birds, while stress-induced corticosterone and prolactin (which have immunostimulatory functions) would be greater in low elevation and malaria-infected birds. As predicted, prolactin was significantly higher in malaria-infected than uninfected females (although more robust sample sizes would help to confirm this relationship), while testosterone trended higher in malaria-infected than uninfected males and, surprisingly, neither baseline nor stress-induced CORT varied with malaria infection. Contrary to our predictions, stress-induced corticosterone was significantly lower in low than high elevation birds while testosterone in males and prolactin in females did not vary by elevation, suggesting that Amakihi hormone modulation across elevation is determined by variables other than disease selection (e.g., timing of breeding, energetic challenges). Our results shed new light on relationships between introduced disease and hormone modulation, and they raise new questions that could be explored in experimental settings.
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Affiliation(s)
- Gabrielle R Names
- Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
| | - Jesse S Krause
- Department of Biology, University of Nevada Reno, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Elizabeth M Schultz
- Department of Biology, Wittenberg University, 200 W Ward Street, Springfield, OH 45504, USA
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, 405 Route de Prissé la Charrière, Villiers-en-Bois, 79360 France
| | - Charline Parenteau
- Centre d'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, 405 Route de Prissé la Charrière, Villiers-en-Bois, 79360 France
| | - Cécile Ribout
- Centre d'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, 405 Route de Prissé la Charrière, Villiers-en-Bois, 79360 France
| | - Thomas P Hahn
- Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
| | - John C Wingfield
- Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
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Rabier R, Lesobre L, Robert A. Reproductive performance in houbara bustard is affected by the combined effects of age, inbreeding and number of generations in captivity. Sci Rep 2021; 11:7813. [PMID: 33837276 PMCID: PMC8035203 DOI: 10.1038/s41598-021-87436-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/30/2021] [Indexed: 11/16/2022] Open
Abstract
Although captive breeding programs are valuable for conservation, they have been shown to be associated with genetic changes, such as adaptation to captivity or inbreeding. In addition, reproductive performance is strongly age-dependent in most animal species. These mechanisms that potentially impact reproduction have often been studied separately, while their interactions have rarely been addressed. In this study, using a large dataset of nine male and female reproductive parameters measured for 12,295 captive houbara bustards (Chlamydotis undulata undulata) over 24 years, we investigated the relative and interactive effects of age, inbreeding and number of generations in captivity on reproduction. We clearly identified (1) senescence patterns in all parameters studied; (2) negative effects of inbreeding on sperm characteristics, display behavior, egg weight, egg volume and hatching probability; and (3) changes in phenotypic values for seven parameters according to number of generations in captivity. However, the effect sizes associated with age were substantially greater than those associated with inbreeding and number of generations in captivity. Beyond the independent effects of these three factors on reproductive parameters, the results highlighted their interactive effects and thus the importance of integrating them in the design of genetic management plans for conservation breeding programs.
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Affiliation(s)
- Robin Rabier
- Reneco International Wildlife Consultant LLC, Abu Dhabi, United Arab Emirates.
- Centre d'Ecologie et des Sciences de la Conservation (CESCO), Muséum national d'Histoire naturelle, Centre National de la Recherche Scientifique, Sorbonne Université, 57 rue Cuvier, CP 135, 75005, Paris, France.
- Emirates Center for Wildlife Propagation, Missour, Morocco.
| | - Loïc Lesobre
- Reneco International Wildlife Consultant LLC, Abu Dhabi, United Arab Emirates
- Emirates Center for Wildlife Propagation, Missour, Morocco
| | - Alexandre Robert
- Centre d'Ecologie et des Sciences de la Conservation (CESCO), Muséum national d'Histoire naturelle, Centre National de la Recherche Scientifique, Sorbonne Université, 57 rue Cuvier, CP 135, 75005, Paris, France
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Kroeger SB, Blumstein DT, Martin JGA. How social behaviour and life-history traits change with age and in the year prior to death in female yellow-bellied marmots. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190745. [PMID: 33678024 DOI: 10.1098/rstb.2019.0745] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Studies in natural populations are essential to understand the evolutionary ecology of senescence and terminal allocation. While there are an increasing number of studies investigating late-life variation in different life-history traits of wild populations, little is known about these patterns in social behaviour. We used long-term individual based data on yellow-bellied marmots (Marmota flaviventer) to quantify how affiliative social behaviours and different life-history traits vary with age and in the last year of life, and how patterns compare between the two. We found that some social behaviours and all life-history traits varied with age, whereas terminal last year of life effects were only observed in life-history traits. Our results imply that affiliative social behaviours do not act as a mechanism to adjust allocation among traits when close to death, and highlight the importance of adopting an integrative approach, studying late-life variation and senescence across multiple different traits, to allow the identification of potential trade-offs. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'
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Affiliation(s)
- Svenja B Kroeger
- Department of Landscape and Biodiversity, The Norwegian Institute of Bioeconomy Research, Klæbuveien 153, Trondheim 7031, Norway
| | - Daniel T Blumstein
- Department of Ecology and Evolutionary Biology, University of California, 621 Young Drive South, Los Angeles, CA 90095-1606, USA.,The Rocky Mountain Biological Laboratory, Box 519, Crested Butte, CO 81224, USA
| | - Julien G A Martin
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, Canada K1N 6N5
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12
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Adámková M, Bílková Z, Tomášek O, Šimek Z, Albrecht T. Feather steroid hormone concentrations in relation to age, sex, and molting time in a long-distance migratory passerine. Ecol Evol 2019; 9:9018-9026. [PMID: 31463000 PMCID: PMC6706234 DOI: 10.1002/ece3.5447] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 06/13/2019] [Accepted: 06/18/2019] [Indexed: 11/23/2022] Open
Abstract
In birds, concentrations of testosterone (T) and corticosterone (Cort) are closely connected with many morphological, behavioral, and other physiological traits, including reproduction, metabolism, immunity, and fitness. The direction of the effect of these hormones on above-mentioned traits, and the potential feedback between hormones are in general unclear; in addition, knowledge on how age and sex can affect T and Cort concentrations is still inconsistent. Our study used a novel method to analyze testosterone and corticosterone in feathers (Tf, Cortf) based on the precolumn chemical derivatization of hormones before liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Unlike previously used methods (RIA, EIA), our analytical procedure allows simultaneous analysis of both hormones from small amounts of feathers (4-25 mg) and, thus, overcomes the problem of insufficient detection limits. We applied this method to reveal associations between Tf and Cortf hormone concentrations and feather growth, age, and sex in feathers grown during the postbreeding (flanks) and prebreeding (tails) periods in barn swallows (Hirundo rustica). There was neither a correlation between prebreeding and postbreeding Tf, nor between prebreeding and postbreeding Cortf. Tail Cortf concentrations were negatively associated with tail feather growth rates. Feather hormone concentrations were correlated in the prebreeding period, negatively in males but positively in females. Both Cortf and Tf were higher in young birds compared to older ones, indicating either an age-related decrease in hormone concentrations within individuals, or the selective disappearance of individuals with high steroid concentrations. Males and females did not differ in Cortf, but Tf concentrations were higher in males than females, particularly during the prebreeding period. In this study, we provide an effective method for analyzing hormones in feathers in an ecological context, especially in situations when the total amount of feathers available for the analysis is limited.
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Affiliation(s)
- Marie Adámková
- Department of Botany and Zoology, Faculty of ScienceMasaryk UniversityBrnoCzech Republic
- Research Centre for Toxic Compounds in the Environment, Faculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Zuzana Bílková
- Research Centre for Toxic Compounds in the Environment, Faculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Oldřich Tomášek
- Institute of Vertebrate BiologyCzech Academy of SciencesBrnoCzech Republic
- Department of Zoology, Faculty of ScienceCharles University in PraguePragueCzech Republic
| | - Zdeněk Šimek
- Research Centre for Toxic Compounds in the Environment, Faculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Tomáš Albrecht
- Institute of Vertebrate BiologyCzech Academy of SciencesBrnoCzech Republic
- Department of Zoology, Faculty of ScienceCharles University in PraguePragueCzech Republic
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13
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Brown ME, Keefer CL, Songsasen N. Factors affecting captive whooping crane egg fertility: A retrospective analysis. J Wildl Manage 2019. [DOI: 10.1002/jwmg.21717] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Megan E. Brown
- Center for Species Survival, Smithsonian Conservation Biology InstituteNational Zoological Park 1500 Remount Road Front Royal VA 22630 USA
| | - Carol L. Keefer
- Department of Animal and Avian SciencesUniversity of Maryland 8127 Regents Dr. College Park MD 20742 USA
| | - Nucharin Songsasen
- Center for Species Survival, Smithsonian Conservation Biology InstituteNational Zoological Park 1500 Remount Road Front Royal VA 22630 USA
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14
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Kroeger C, Crocker DE, Thompson DR, Torres LG, Sagar P, Shaffer SA. Variation in Corticosterone Levels in Two Species of Breeding Albatrosses with Divergent Life Histories: Responses to Body Condition and Drivers of Foraging Behavior. Physiol Biochem Zool 2019; 92:223-238. [PMID: 30741599 DOI: 10.1086/702656] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Corticosterone (CORT) is a glucocorticoid hormone that maintains energy balance and can modulate foraging behaviors in seabirds. However, CORT responses are not always predictable under similar biophysical conditions and do not necessarily influence the same behaviors across breeding stages and species. To enhance our understanding of CORT's role as a proximate determinant of foraging behavior and energy maintenance, we examined the relationships between body condition, CORT, foraging behavior, and foraging success between two sympatric breeding albatross species with differing foraging strategies and life histories, the Campbell albatross (Thalassarache impavida) and the gray-headed albatross (Thalassarache chrysostoma), from Campbell Island, New Zealand. Pre- and postforaging CORT did not differ between species or stage, potentially as a result of behavioral plasticity or different functional roles of CORT across stages. Unexpectedly, body condition did not correlate with preforaging CORT during incubation, although a negative correlation was observed in Campbell albatrosses during the guard stage. Furthermore, CORT mediated foraging success in both species and stages, but CORT mediated foraging behavior only in incubation-stage Campbell albatrosses that had shorter foraging ranges with higher pretrip CORT. Additionally, CORT positively correlated with mass gain and the time elapsed since the last feeding event in guard-stage albatrosses. Our results highlight the complexity of CORT in mediating energy balance in free-ranging animals. Our results also support that if CORT is to be usefully interpreted, breeding stage must be considered because the physiological and behavioral functionality of CORT may differ across stages, with enhanced sensitivity to energy reserves during chick rearing.
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15
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Casagrande S, Hau M. Enzymatic antioxidants but not baseline glucocorticoids mediate the reproduction-survival trade-off in a wild bird. Proc Biol Sci 2018; 285:rspb.2018.2141. [PMID: 30487312 DOI: 10.1098/rspb.2018.2141] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 11/07/2018] [Indexed: 12/21/2022] Open
Abstract
The trade-off between reproductive investment and survival is central to life-history theory, but the relative importance and the complex interactions among the physiological mechanisms mediating it are still debated. Here we experimentally tested whether baseline glucocorticoid hormones, the redox system or their interaction mediate reproductive investment-survival trade-offs in wild great tits (Parus major). We increased the workload of parental males by clipping three feathers on each wing, and 5 days later determined effects on baseline corticosterone concentrations (Cort), redox state (reactive oxygen metabolites, protein carbonyls, glutathione peroxidase [GPx], total non-enzymatic antioxidants), body mass, body condition, reproductive success and survival. Feather-clipping did not affect fledgling numbers, chick body condition, nest provisioning rates or survival compared with controls. However, feather-clipped males lost mass and increased both Cort and GPx concentrations. Within feather-clipped individuals, GPx increases were positively associated with reproductive investment (i.e. male nest provisioning). Furthermore, within all individuals, males that increased GPx suffered reduced survival rates. Baseline Cort increases were related to mass loss but not to redox state, nest provisioning or male survival. Our findings provide experimental evidence that changes in the redox system are associated with the trade-off between reproductive investment and survival, while baseline Cort may support this trade-off indirectly through a link with body condition. These results also emphasize that plastic changes in individuals, rather than static levels of physiological signals, may mediate life-history trade-offs.
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Affiliation(s)
- Stefania Casagrande
- Department of Evolutionary Physiology, Max Planck Institute for Ornithology, Seewiesen, Starnberg, Germany
| | - Michaela Hau
- Department of Evolutionary Physiology, Max Planck Institute for Ornithology, Seewiesen, Starnberg, Germany
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16
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Clay TA, Pearmain EJ, McGill RAR, Manica A, Phillips RA. Age‐related variation in non‐breeding foraging behaviour and carry‐over effects on fitness in an extremely long‐lived bird. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13120] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas A. Clay
- British Antarctic SurveyNatural Environment Research Council Cambridge UK
- Department of ZoologyUniversity of Cambridge Cambridge UK
| | | | - Rona A. R. McGill
- NERC Life Sciences Mass Spectrometry FacilityScottish Universities Environmental Research Centre East Kilbride UK
| | - Andrea Manica
- Department of ZoologyUniversity of Cambridge Cambridge UK
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17
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Hennin HL, Dey CJ, Bêty J, Gilchrist HG, Legagneux P, Williams TD, Love OP. Higher rates of prebreeding condition gain positively impacts clutch size: A mechanistic test of the condition‐dependent individual optimization model. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13133] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Holly L. Hennin
- Department of Biological SciencesUniversity of Windsor Windsor Ontario Canada
| | - Cody J. Dey
- Great Lakes Institute for Environmental ResearchUniversity of Windsor Windsor Ontario Canada
| | - Joël Bêty
- Département de Biologie and Centre d'études nordiquesUniversité du Québec à Rimouski Rimouski Québec Canada
| | - H. Grant Gilchrist
- National Wildlife Research CentreEnvironment and Climate Change Canada Ottawa Ontario Canada
| | - Pierre Legagneux
- Département de Biologie and Centre d'études nordiquesUniversité du Québec à Rimouski Rimouski Québec Canada
| | - Tony D. Williams
- Department of Biological SciencesSimon Fraser University Burnaby British Columbia Canada
| | - Oliver P. Love
- Department of Biological SciencesUniversity of Windsor Windsor Ontario Canada
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18
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Smiley KO, Adkins-Regan E. Lowering prolactin reduces post-hatch parental care in male and female zebra finches (Taeniopygia guttata). Horm Behav 2018; 98:103-114. [PMID: 29287798 DOI: 10.1016/j.yhbeh.2017.12.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 12/18/2017] [Accepted: 12/23/2017] [Indexed: 11/21/2022]
Abstract
Parental care is a widespread phenomenon observed in many diverse taxa. Neuroendocrine systems have long been thought to play an important role in stimulating the onset of parental behavior. In most birds with altricial young, circulating prolactin (PRL) levels are low during non-breeding times and significantly increase during late incubation and early post-hatch chick care. Because of this pattern, PRL has been suggested to be involved in the initiation of parental care in birds, but rarely has this hypothesis been causally tested. To begin testing the hypothesis, we inhibited the release of endogenous PRL with bromocriptine (BR) on the 3days prior to hatching in incubating parents and the first 2days of post-hatch care, when PRL was found to be highest in zebra finches. Nest temperatures were recorded during all 5days and parental behavior was recorded on days 1-2 post-hatch. In addition to hormonal systems, reproductive experience may also influence parental care; therefore, we tested age-matched inexperienced and experienced pairs in each group. BR either eliminated or drastically reduced chick brooding and feeding behavior, resulting in decreased nest temperatures on days 1 and 2 post-hatch. Experienced control birds fed chicks more than inexperienced birds and control females fed more than males. Chick feeding behavior was positively correlated in control male-female pairs, but not in BR pairs. This is one of the few causal studies to demonstrate that PRL is necessary for post-hatch care in a biparental songbird, and is the first to show this effect in zebra finches.
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Affiliation(s)
- Kristina O Smiley
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA.
| | - Elizabeth Adkins-Regan
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA; Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
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19
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Fitness consequences of peak reproductive effort in a resource pulse system. Sci Rep 2017; 7:9335. [PMID: 28839275 PMCID: PMC5571191 DOI: 10.1038/s41598-017-09724-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/28/2017] [Indexed: 01/11/2023] Open
Abstract
The age trajectory of reproductive performance of many iteroparous species features an early - life increase in performance followed by a late - life senescent decline. The largest contribution of lifetime reproductive success is therefore gained at the age at which reproductive performance peaks. Using long term data on North American red squirrels we show that the environmental conditions individuals encountered could cause variation among individuals in the “height” and timing of this peak, contributing to life history variation and fitness in this population that experiences irregular resource pulses. As expected, high peak effort was positively associated with lifetime reproductive output up to a high level of annual effort. Furthermore, individuals that matched their peak reproductive effort to an anticipated resource pulse gained substantial fitness benefits through recruiting more offspring over their lifetime. Individual variation in peak reproductive effort thus has strong potential to shape life history evolution by facilitating adaptation to fluctuating environments.
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20
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Beaulieu M, Ancel A, Chastel O, Criscuolo F, Raclot T. Socially-induced variation in physiological mediators of parental care in a colonial bird. Horm Behav 2017; 93:39-46. [PMID: 28356224 DOI: 10.1016/j.yhbeh.2017.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/11/2017] [Accepted: 03/19/2017] [Indexed: 10/19/2022]
Abstract
Social facilitation of reproduction occurs in humans and animals, and may represent one of the bases of reproduction in groups. However, its underlying physiological mechanisms remain largely unexplored. Here, we found in a colonial bird, the Adélie penguin (Pygoscelis adeliae), that the number of parental interactions (nest relief ceremonies) performed by breeding individuals on the colony was positively related to prolactin levels in other breeding individuals exposed to these interactions (i.e. focal individuals). As prolactin is typically involved in the expression of parental behaviour in birds, this suggests that parental interactions by conspecifics represent social cues that might increase parental motivation in focal individuals. Moreover, parental interactions were not related to corticosterone levels in focal individuals, suggesting that these social cues were not stressful for penguins. However, social stimulation still had a cost for focal individuals, as it was negatively related to their antioxidant defences (a component of self-maintenance). As social stimulation was also positively related to prolactin levels, this highlights the fact that social stimulation acts on the trade-off between reproduction and self-maintenance. For the first time, the results of the current study shed light on the physiological factors potentially underlying social facilitation of parental care. Importantly, they suggest that, even though social facilitation of parental care may increase breeding performance, it can also negatively affect other fitness components.
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Affiliation(s)
- Michaël Beaulieu
- Zoological Institute & Museum, University of Greifswald, Johann-Sebastian-Bach-Str. 11/12, 17489 Greifswald, Germany.
| | - André Ancel
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France; CNRS, UMR7178, 67087 Strasbourg, France
| | - Olivier Chastel
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR7372-CNRS/Univ. La Rochelle, F-79360, France
| | - François Criscuolo
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France; CNRS, UMR7178, 67087 Strasbourg, France
| | - Thierry Raclot
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France; CNRS, UMR7178, 67087 Strasbourg, France
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21
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Madliger CL, Love OP. Conservation implications of a lack of relationship between baseline glucocorticoids and fitness in a wild passerine. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:2730-2743. [PMID: 27763712 DOI: 10.1002/eap.1401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 06/09/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
The application of physiological measures to conservation monitoring has been gaining momentum and, while a suite of physiological traits are available to ascertain disturbance and condition in wildlife populations, glucocorticoids (i.e., GCs; cortisol and corticosterone) are the most heavily employed. The interpretation of GC levels as sensitive indicators of population change necessitates that GCs and metrics of population persistence are linked. However, the relationship between GCs and fitness may be highly context-dependent, changing direction, or significance, depending on the GC measure, fitness metric, life history stage, or other intrinsic and extrinsic contexts considered. We examined the relationship between baseline plasma corticosterone (CORT) levels measured at two periods of the breeding season and three metrics of fitness (offspring quality, reproductive output, and adult survival) in female Tree Swallows (Tachycineta bicolor). Specifically, we investigated whether (1) a relationship between baseline CORT metrics and fitness exists in our population, (2) whether the inclusion of energetic contexts, such as food availability, reproductive investment, or body mass, could alter or improve the strength of the relationship between CORT and fitness, and (3) whether energetic contexts could better predict fitness compared to CORT metrics. Importantly, we investigated these relationships in both natural conditions and under an experimental manipulation of foraging profitability (feather clipping) to determine the influence of an environmental constraint on GC-fitness relationships. We found a lack of relationship between baseline CORT and both short- and long-term metrics of fitness in control and clipped birds. In contrast, loss in body mass over reproduction positively predicted reproductive output (number of chicks leaving the nest) in control birds; however, the relationship was characterized by a low R2 (5%), limiting the predictive capacity, and therefore the application potential, of such a measure in a conservation setting. Our results stress the importance of ground-truthing GC-fitness relationships and indicate that baseline GCs will likely not be easily employed as conservation biomarkers across some species and life history stages. Given the accumulating evidence of temporally dynamic, inconsistent, and context-dependent GC-fitness relationships, placing effort towards directly measuring fitness traits, rather than plasma GC levels, will likely be more worthwhile for many conservation endeavours.
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Affiliation(s)
- Christine L Madliger
- Department of Biological Sciences, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada
| | - Oliver P Love
- Department of Biological Sciences, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada
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22
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Lifetime variation in feather corticosterone levels in a long-lived raptor. Oecologia 2016; 183:315-326. [DOI: 10.1007/s00442-016-3708-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 08/16/2016] [Indexed: 10/21/2022]
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23
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Smiley KO, Adkins-Regan E. Relationship between prolactin, reproductive experience, and parental care in a biparental songbird, the zebra finch (Taeniopygia guttata). Gen Comp Endocrinol 2016; 232:17-24. [PMID: 26602378 DOI: 10.1016/j.ygcen.2015.11.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/14/2015] [Accepted: 11/17/2015] [Indexed: 12/27/2022]
Abstract
Hormonal systems have long been thought to play an important role in stimulating the onset of parental behavior, a critical component of reproductive success in a variety of taxa. Elevations in the peptide hormone prolactin (PRL) have been repeatedly positively correlated with the onset and maintenance of parental care across vertebrate species. A causal role for PRL in parental care has been established in several mammalian species, but less evidence for a causal role of PRL and parental care exists in birds. The zebra finch, a socially monogamous, biparental songbird, is an exceptionally useful animal model to study parental care and other close social relationships. Both sexes share parental care equally, exhibit the same parental behaviors, and show a marked improvement in breeding success with experience. We hypothesize that PRL is critically involved in the expression of zebra finch parental care and predict that circulating PRL levels will increase with breeding experience. To begin testing this, we measured plasma PRL concentrations in 14 male-female zebra finch pairs (N=28) across two breeding cycles, using a repeated measures design. PRL was measured in the birds' first, reproductively inexperienced, breeding cycle beginning at courtship and extending through chick fledging. PRL was measured again during the birds' second, reproductively experienced, breeding cycle, beginning with egg laying until chick fledging. We found that plasma PRL is significantly elevated from non-breeding concentrations during late incubation and early post-hatch care and that this elevation is greater in the reproductively experienced cycle compared to the inexperienced cycle. Findings of this study will be used to inform hypotheses and predictions for future experimental manipulations of PRL during parental care.
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Affiliation(s)
- Kristina O Smiley
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA.
| | - Elizabeth Adkins-Regan
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA; Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
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24
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Madliger CL, Love OP. Do baseline glucocorticoids simultaneously represent fitness and environmental quality in a declining aerial insectivore? OIKOS 2016. [DOI: 10.1111/oik.03354] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christine L. Madliger
- Dept of Biological Sciences; Univ. of Windsor; 401 Sunset Ave. Windsor ON N9B 2P4 Canada
| | - Oliver P. Love
- Dept of Biological Sciences; Univ. of Windsor; 401 Sunset Ave. Windsor ON N9B 2P4 Canada
- Great Lakes Inst. for Environmental Research; Univ. of Windsor; ON Canada
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25
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Angelier F, Wingfield JC, Tartu S, Chastel O. Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review. Horm Behav 2016. [PMID: 26211371 DOI: 10.1016/j.yhbeh.2015.07.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This article is part of a Special Issue "Parental Care". In vertebrates, adjustments of physiology and behavior to environmental changes are often mediated by central physiological mechanisms, and more specifically by hormonal mechanisms. As a consequence, these mechanisms are thought to orchestrate life-history decisions in wild vertebrates. For instance, investigating the hormonal regulation of parental behavior is relevant to evaluate how parents modulate their effort according to specific environmental conditions. Surprisingly and despite being classically known as the 'parental hormone', prolactin has been overlooked in birds relative to this context. Our aim is to review evidence that changes in prolactin levels can mediate, at least to some extent, the response of breeding birds to environmental conditions. To do so, we first examine current evidence and limits for the role of prolactin in mediating parental behavior in birds. Second, we emphasize the influence of environmental conditions and stressors on circulating prolactin levels. In addition, we review to what extent prolactin levels are a reliable predictor of breeding success in wild birds. By linking environmental conditions, prolactin regulation, parental behavior, and breeding success, we highlight the potential role of this hormone in mediating parental decisions in birds. Finally, we also review the potential role of prolactin in mediating other life history decisions such as clutch size, re-nesting, and the timing of molt. By evaluating the influence of stressors on circulating prolactin levels during these other life-history decisions, we also raise new hypotheses regarding the potential of the prolactin stress response to regulate the orchestration of the annual cycle when environmental changes occur. To sum up, we show in this review that prolactin regulation has a strong potential to allow ecological physiologists to better understand how individuals adjust their life-history decisions (clutch size, parental behavior, re-nesting, and onset of molt) according to the environmental conditions they encounter and we encourage further research on that topic.
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Affiliation(s)
- Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France.
| | - John C Wingfield
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Sabrina Tartu
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Olivier Chastel
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
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26
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Christensen D, Vleck CM. Effects of age and reproductive experience on the distribution of prolactin and growth hormone secreting cells in the anterior pituitary of a passerine. Gen Comp Endocrinol 2015; 222:54-61. [PMID: 26119185 DOI: 10.1016/j.ygcen.2015.05.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 05/16/2015] [Accepted: 05/27/2015] [Indexed: 11/20/2022]
Abstract
Plasma prolactin (PRL) is released from lactotrophs in the anterior pituitary. As plasma PRL levels rise during incubation in domestic fowl, the number of lactotrophs (PRL-immunoreactive, PRL-IR cells) increases while the number of growth hormone secreting cells, somatotrophs (GH-IR cells), declines. We measured plasma PRL levels using radioimmunoassay (RIA) and examined the distribution of lactotrophs and somatotrophs in the anterior pituitary of breeding and nonbreeding zebra finches of known ages with and without prior breeding experience using fluorescent immunohistochemistry (IHC). Plasma PRL levels were higher in breeding than in nonbreeding birds, regardless of age, sex, or previous breeding history. PRL-IR cells were localized primarily, but not exclusively, to the cephalic aspect of the anterior pituitary (AP) and along the ventral margin. Birds with prior reproductive experience had more PRL-IR cells than birds with no prior reproductive experience and breeders had slightly higher PRL-IR cell counts than did nonbreeders, but there was no correlation between the number of PRL-IR cells and plasma PRL levels. GH-IR cells were concentrated in the caudal aspect of the AP with some cells in the cephalic lobe, but numbers did not differ between any of the groups studied. An increase in PRL-IR cells corresponded with an increase in GH-IR cells. An increase in lactotroph number with reproductive experience in zebra finches may facilitate future reproductive events by allowing for more robust PRL secretion and increased reproductive success.
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Affiliation(s)
- Debora Christensen
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
| | - Carol M Vleck
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
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Hämäläinen A, Heistermann M, Kraus C. The stress of growing old: sex- and season-specific effects of age on allostatic load in wild grey mouse lemurs. Oecologia 2015; 178:1063-75. [DOI: 10.1007/s00442-015-3297-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 03/13/2015] [Indexed: 11/29/2022]
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28
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Intra-individual variability in fecal cortisol metabolites varies with lifetime exploration and reproductive life history in eastern chipmunks (Tamias striatus). Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-014-1812-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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29
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Pardo D, Barbraud C, Weimerskirch H. Females better face senescence in the wandering albatross. Oecologia 2014; 173:1283-94. [PMID: 23797411 DOI: 10.1007/s00442-013-2704-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 06/04/2013] [Indexed: 11/25/2022]
Abstract
Sex differences in lifespan and aging are widespread among animals. Since investment in current reproduction can have consequences on other life-history traits, the sex with the highest cost of breeding is expected to suffer from an earlier and/or stronger senescence. This has been demonstrated in polygynous species that are highly dimorphic. However in monogamous species where parental investment is similar between sexes, sex-specific differences in aging patterns of life-history traits are expected to be attenuated. Here, we examined sex and age influences on demographic traits in a very long-lived and sexually dimorphic monogamous species, the wandering albatross (Diomedea exulans). We modelled within the same model framework sex-dependent variations in aging for an array of five life-history traits: adult survival, probability of returning to the breeding colony, probability of breeding and two measures of breeding success (hatching and fledging). We show that life-history traits presented contrasted aging patterns according to sex whereas traits were all similar at young ages. Both sexes exhibited actuarial and reproductive senescence, but, as the decrease in breeding success remained similar for males and females, the survival and breeding probabilities of males were significantly more affected than females. We discuss our results in the light of the costs associated to reproduction, age-related pairing and a biased operational sex-ratio in the population leading to a pool of non-breeders of potentially lower quality and therefore more subject to death or breeding abstention. For a monogamous species with similar parental roles, the patterns observed were surprising and when placed in a gradient of observed age/sex-related variations in life-history traits, wandering albatrosses were intermediate between highly dimorphic polygynous and most monogamous species.
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Fine-scale spatial age segregation in the limited foraging area of an inshore seabird species, the little penguin. Oecologia 2014; 176:399-408. [PMID: 25038901 DOI: 10.1007/s00442-014-3018-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
Abstract
Competition for food resources can result in spatial and dietary segregation among individuals from the same species. Few studies have looked at such segregations with the combined effect of sex and age in species with short foraging ranges. In this study we examined the 3D spatial use of the environment in a species with a limited foraging area. We equipped 26 little penguins (Eudyptula minor) of known age, sex, and breeding output with GPS (location) and accelerometer (body acceleration and dive depth) loggers. We obtained dietary niche information from the isotopic analysis of blood tissue. We controlled for confounding factors of foraging trip length and food availability by sampling adults at guard stage when parents usually make one-day trips. We observed a spatial segregation between old (>11 years old) and middle-aged penguins (between 5 and 11 years old) in the foraging area. Old penguins foraged closer to the shore, in shallower water. Despite observing age-specific spatial segregation, we found no differences in the diving effort and foraging efficiency between age classes and sexes. Birds appeared to target similar prey types, but showed age-specific variation in their isotopic niche width. We hypothesize that this age-specific segregation was primarily determined by a "cohort effect" that would lead individuals sharing a common life history (i.e. having fledged and dispersed around the same age) to forage preferentially together or to share similar foraging limitations.
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31
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Riechert J, Chastel O, Becker PH. Regulation of Breeding Behavior: Do Energy-Demanding Periods Induce a Change in Prolactin or Corticosterone Baseline Levels in the Common Tern (Sterna hirundo)? Physiol Biochem Zool 2014; 87:420-31. [DOI: 10.1086/675682] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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32
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Stress hormones in relation to breeding status and territory location in colonial king penguin: a role for social density? Oecologia 2014; 175:763-72. [DOI: 10.1007/s00442-014-2942-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 04/02/2014] [Indexed: 01/28/2023]
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33
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Franci CD, Guillemette M, Pelletier E, Chastel O, Bonnefoi S, Verreault J. Endocrine status of a migratory bird potentially exposed to the Deepwater Horizon oil spill: a case study of northern gannets breeding on Bonaventure Island, Eastern Canada. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 473-474:110-116. [PMID: 24361782 DOI: 10.1016/j.scitotenv.2013.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 06/03/2023]
Abstract
The Deepwater Horizon oil spill caused the death of a large number of seabirds in the Gulf of Mexico in 2010. However, the long term consequences of oil exposure on migratory birds overwintering in this area have received limited attention. The present study aimed to investigate the impact of oil contamination (e.g., polycyclic aromatic hydrocarbons (PAHs)) on the circulating status of prolactin and corticosterone, two hormones that influence reproductive success in birds, in Northern gannets (Morus bassanus) breeding on Bonaventure Island, Eastern Canada. Using light-based geolocators, it was found that 23.5% of Northern gannets from Bonaventure Island overwintered in the Gulf of Mexico in 2010-2011; the remainder of this population overwintered along the Atlantic Coast of the United States. PAH concentrations (eight compounds) in gannet blood cells were all found to be under the method limits of quantification, which could be the result of the ability of seabirds to metabolize these compounds and the time elapsed between oil exposure and blood sampling. Corticosterone and prolactin levels as well as body mass did not differ between the two major birds' wintering sites. Moreover, levels of both these hormones did not vary from early to late incubation period. Present results suggest that if Bonaventure Island-breeding Northern gannets had been exposed to oil in the Gulf of Mexico in the aftermath of this historical spill, this exposure could not be associated with changes in hormonal status and body mass in breeding individuals.
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Affiliation(s)
- Cynthia D Franci
- Centre de Recherche en Toxicologie de l'environnement (TOXEN), Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montreal, QC, Canada
| | - Magella Guillemette
- Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC, Canada
| | - Emilien Pelletier
- Institut des Sciences de la mer de Rimouski (ISMER), Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, QC, Canada
| | - Olivier Chastel
- Centre d'Études Biologiques de Chizé, Centre National de la Recherche Scientifique, Villiers en Bois, Deux-Sèvres F-79360, France
| | - Salomé Bonnefoi
- Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC, Canada
| | - Jonathan Verreault
- Centre de Recherche en Toxicologie de l'environnement (TOXEN), Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montreal, QC, Canada.
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34
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Pardo D, Barbraud C, Weimerskirch H. What shall I do now? State-dependent variations of life-history traits with aging in Wandering Albatrosses. Ecol Evol 2014; 4:474-87. [PMID: 24634731 PMCID: PMC3936393 DOI: 10.1002/ece3.882] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 10/14/2013] [Accepted: 10/15/2013] [Indexed: 11/23/2022] Open
Abstract
Allocation decisions depend on an organism's condition which can change with age. Two opposite changes in life-history traits are predicted in the presence of senescence: either an increase in breeding performance in late age associated with terminal investment or a decrease due to either life-history trade-offs between current breeding and future survival or decreased efficiency at old age. Age variation in several life-history traits has been detected in a number of species, and demographic performances of individuals in a given year are influenced by their reproductive state the previous year. Few studies have, however, examined state-dependent variation in life-history traits with aging, and they focused mainly on a dichotomy of successful versus failed breeding and non-breeding birds. Using a 50-year dataset on the long-lived quasi-biennial breeding wandering albatross, we investigated variations in life-history traits with aging according to a gradient of states corresponding to potential costs of reproduction the previous year (in ascending order): non-breeding birds staying at sea or present at breeding grounds, breeding birds that failed early, late or were successful. We used multistate models to study survival and decompose reproduction into four components (probabilities of return, breeding, hatching, and fledging), while accounting for imperfect detection. Our results suggest the possible existence of two strategies in the population: strict biennial breeders that exhibited almost no reproductive senescence and quasi-biennial breeders that showed an increased breeding frequency with a strong and moderate senescence on hatching and fledging probabilities, respectively. The patterns observed on survival were contrary to our predictions, suggesting an influence of individual quality rather than trade-offs between reproduction and survival at late ages. This work represents a step further into understanding the evolutionary ecology of senescence and its relationship with costs of reproduction at the population level. It paves the way for individual-based studies that could show the importance of intra-population heterogeneity in those processes.
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Affiliation(s)
- Deborah Pardo
- CEBC-CNRS UPR 1934 F 79360, Villiers-en-Bois, France
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35
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Byrnes EM, Casey K, Carini LM, Bridges RS. Reproductive experience alters neural and behavioural responses to acute oestrogen receptor α activation. J Neuroendocrinol 2013; 25:1280-1289. [PMID: 24118285 PMCID: PMC4269101 DOI: 10.1111/jne.12113] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 09/04/2013] [Accepted: 10/09/2013] [Indexed: 01/25/2023]
Abstract
Reproductive experience (i.e. parturition and lactation) leads to persistent alterations in anxiety-like behaviour that are influenced by the oestrous cycle. We recently found that repeated administration of the selective oestrogen receptors (ER)α agonist propyl-pyrazole triol (PPT) results in anxiolytic-like behaviours on the elevated plus maze (EPM) in primiparous (but not nulliparous) female rats. The present study examined the effects of the acute administration of PPT on EPM behaviour in primiparous and aged-matched, nulliparous female rats. In addition, corticosterone secretion, corticotrophin-releasing hormone (CRH) gene expression and expression of the immediate early gene product Fos in the paraventricular nucleus (PVN) and amygdala were measured either after EPM testing or in home cage controls. Acute PPT administration significantly modified EPM behaviour as a function of reproductive experience, with nulliparous females tending toward increased anxiety-like behaviours and primiparous females tending toward decreased anxiety-like behaviours. In home cage controls, PPT increased corticosterone secretion in all females; however, both vehicle- and PPT-treated, primiparous females had reduced corticosterone levels compared to their nulliparous counterparts. Significant effects of PPT on CRH mRNA within the PVN were observed after the administration of PPT but only in primiparous females tested on the EPM. PPT also increased Fos expression within the PVN of EPM-exposed females; however, both vehicle- and PPT-treated primiparous females had reduced Fos expression compared to nulliparous females. In the amygdala, PPT increased Fos immunoreactivity in the central but not the medial or basolateral amygdala, although these effects were only observed in home cage females. Additionally, both vehicle- and PPT-treated home cage, primiparous females had increased Fos in the central nucleus of the amygdala compared to nulliparous controls. Overall, these data demonstrate that reproductive experience alters the behavioural response to acute ERα activation. Moreover, the findings suggest that central regulation of the hypothalamic-adrenal-pituitary axis is modified as a consequence of reproductive experience.
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Affiliation(s)
- E M Byrnes
- Tufts University, Cummings School of Veterinary Medicine, North Grafton, MA, USA
| | - K Casey
- Tufts University, Cummings School of Veterinary Medicine, North Grafton, MA, USA
| | - L M Carini
- Tufts University, Cummings School of Veterinary Medicine, North Grafton, MA, USA
| | - R S Bridges
- Tufts University, Cummings School of Veterinary Medicine, North Grafton, MA, USA
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36
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Angelier F, Wingfield JC. Importance of the glucocorticoid stress response in a changing world: theory, hypotheses and perspectives. Gen Comp Endocrinol 2013; 190:118-28. [PMID: 23770214 DOI: 10.1016/j.ygcen.2013.05.022] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/19/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
In this perspective paper, we emphasize the importance that integrative mechanisms, and especially the GC (glucocorticoid) stress response, can play in the ability of vertebrates to cope with ongoing global change. The GC stress response is an essential mediator of allostasis (i.e., the responses of an organism to a perturbation) that aims at maintaining stability (homeostasis) despite changing conditions. The GC stress response is a complex mechanism that depends on several physiological components and aims at promoting immediate survival at the expense of other life-history components (e.g., reproduction) when a labile perturbation factor (LPF) occurs. Importantly, this mechanism is somewhat flexible and its degree of activation can be adjusted to the fitness costs and benefits that result from the GC stress response. Therefore, this GC stress response mediates life-history decisions and is involved in the regulation of important life-history trade-offs. By inducing abrupt and rapid changes in the regime of LPFs, we believe that global change can affect the efficiency of the GC stress response to maintain homeostasis and to appropriately regulate these trades-offs. This dysfunction may result in an important mismatch between new LPFs and the associated GC stress response and, thus, in the inability of vertebrates to cope with a changing world. In that context, it is essential to better understand how the GC stress response can be adjusted to new LPFs through micro-evolution, phenotypic plasticity and phenotypic flexibility (habituation and sensitization). This paper sets up a theoretical framework, hypotheses and new perspectives that will allow testing and better understanding how the GC stress response can help or constrain individuals, populations and species to adjust to ongoing global change.
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Affiliation(s)
- Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS, 79360 Villiers en Bois, France.
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37
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DuRant SE, Hopkins WA, Hepp GR, Romero LM. Energetic constraints and parental care: is corticosterone indicative of energetic costs of incubation in a precocial bird? Horm Behav 2013; 63:385-91. [PMID: 23232333 DOI: 10.1016/j.yhbeh.2012.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 11/22/2012] [Accepted: 12/01/2012] [Indexed: 10/27/2022]
Abstract
Suppression of the adrenocortical response (e.g., corticosterone release) to an acute stressor is a physiological adjustment thought to decrease the likelihood of avian parents abandoning their nests. However, some periods of parental care, like incubation, are energetically costly, thus corticosterone could increase during these stages to allow incubating parents to utilize energy reserves. Wood ducks (Aix sponsa) have ~30 day incubation periods and only the female incubates the eggs. We hypothesized that corticosterone would be important in regulating energy availability during incubation in this species. Because resources invested in reproduction increase with clutch size, we also hypothesized that clutch size would influence plasma corticosterone during incubation. We measured baseline and stress-induced corticosterone in incubating females during early and late stages of incubation. At both stages of incubation all hens had low baseline corticosterone levels. However, we found that stress-induced corticosterone was 105% greater late in incubation than early in incubation. We also detected a significant negative correlation between female body mass and stress-induced corticosterone late in incubation, but not during the early stages of incubation. Furthermore, we found a significant positive relationship between stress-induced corticosterone and clutch size. These lines of evidence support the hypothesis that incubation in wood ducks is energetically costly and corticosterone is important in supporting the energetic demands of incubating hens. Our findings suggest that corticosterone's role in supporting parental care behaviors are dynamic and are influenced by several factors and that there is a greater physiological cost associated with incubating larger clutches.
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Affiliation(s)
- Sarah E DuRant
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061, USA.
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38
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Angelier F, Wingfield JC, Trouvé C, de Grissac S, Chastel O. Modulation of the prolactin and the corticosterone stress responses: do they tell the same story in a long-lived bird, the Cape petrel? Gen Comp Endocrinol 2013; 182:7-15. [PMID: 23142160 DOI: 10.1016/j.ygcen.2012.10.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 10/09/2012] [Accepted: 10/22/2012] [Indexed: 11/15/2022]
Abstract
Over the last decades, the corticosterone stress response has been suggested as a major physiological tool to understand what strategy an individual might adopt in response to environmental perturbations. More recently, another hormone related to parental care--prolactin--has been suggested as a complementary tool to investigate this question. Indeed, both of these hormones are affected by stressors and are involved in parental decisions, such as deserting the nest. Because of these similarities, it remains unclear what the functional distinction between the prolactin and corticosterone stress responses is. Here, we investigated whether natural variations of the corticosterone and prolactin stress responses are functionally linked in free-living Cape petrel (Daption capense) parents. If prolactin and corticosterone mediate the same functional response to a stressor and are the proxies of the same response, we predict that corticosterone and prolactin stress responses (1) will be modulated according to the same factors; (2) will affect reproductive performances in the same way; and, (3) of course, will be correlated. Contrary to these predictions, we found that the corticosterone and prolactin stress responses were respectively modulated according to body condition and breeding status. Moreover, prolactin levels, but not corticosterone levels, were related to hatching success in this species. Finally, we did not find any significant correlation between these two stress responses under any circumstances (failed breeders, incubating or chick rearing birds) and this result was overall supported by a review of the existing literature. Therefore, these two stress responses do not seem to be tightly linked and we believe that they may provide complementary pieces of information on parental investment in birds.
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Affiliation(s)
- Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS, 79360 Villiers en Bois, France.
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39
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Blickley JL, Word KR, Krakauer AH, Phillips JL, Sells SN, Taff CC, Wingfield JC, Patricelli GL. Experimental chronic noise is related to elevated fecal corticosteroid metabolites in lekking male greater Sage-Grouse (Centrocercus urophasianus). PLoS One 2012; 7:e50462. [PMID: 23185627 PMCID: PMC3502302 DOI: 10.1371/journal.pone.0050462] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/22/2012] [Indexed: 11/19/2022] Open
Abstract
There is increasing evidence that individuals in many species avoid areas exposed to chronic anthropogenic noise, but the impact of noise on those who remain in these habitats is unclear. One potential impact is chronic physiological stress, which can affect disease resistance, survival and reproductive success. Previous studies have found evidence of elevated stress-related hormones (glucocorticoids) in wildlife exposed to human activities, but the impacts of noise alone are difficult to separate from confounding factors. Here we used an experimental playback study to isolate the impacts of noise from industrial activity (natural gas drilling and road noise) on glucocorticoid levels in greater sage-grouse (Centrocercus urophasianus), a species of conservation concern. We non-invasively measured immunoreactive corticosterone metabolites from fecal samples (FCMs) of males on both noise-treated and control leks (display grounds) in two breeding seasons. We found strong support for an impact of noise playback on stress levels, with 16.7% higher mean FCM levels in samples from noise leks compared with samples from paired control leks. Taken together with results from a previous study finding declines in male lek attendance in response to noise playbacks, these results suggest that chronic noise pollution can cause greater sage-grouse to avoid otherwise suitable habitat, and can cause elevated stress levels in the birds who remain in noisy areas.
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Affiliation(s)
- Jessica L. Blickley
- Dept of Evolution and Ecology, University of California Davis, Davis, California, United States of America
| | - Karen R. Word
- Dept of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California, United States of America
| | - Alan H. Krakauer
- Dept of Evolution and Ecology, University of California Davis, Davis, California, United States of America
| | - Jennifer L. Phillips
- Dept of Evolution and Ecology, University of California Davis, Davis, California, United States of America
| | - Sarah N. Sells
- University of Montana, Wildlife Biology Program, Missoula, Montana, United States of America
| | - Conor C. Taff
- Dept of Evolution and Ecology, University of California Davis, Davis, California, United States of America
| | - John C. Wingfield
- Dept of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California, United States of America
| | - Gail L. Patricelli
- Dept of Evolution and Ecology, University of California Davis, Davis, California, United States of America
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Is the additional effort of renesting linked to a hormonal change in the common tern? J Comp Physiol B 2012; 183:431-41. [PMID: 23064552 DOI: 10.1007/s00360-012-0713-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/14/2012] [Accepted: 09/25/2012] [Indexed: 10/27/2022]
Abstract
The production of and care for a replacement clutch can bear costs in terms of future reproduction or survival. However, renesting is quite common among seabirds and can contribute considerably to individual fitness. Prolactin and corticosterone are two hormones involved in the mediation of breeding behavior and, as they are linked to body condition or effort, it is of interest if these hormone values change during a second demanding breeding phase within a year. We compared baseline prolactin and corticosterone between the first and the renesting attempt in common terns (Sterna hirundo) on individual level. Therefore, in addition to control birds, 37 breeders were sampled during incubation of their first and their replacement clutch in 2008 and 2009. Blood samples were taken non-invasively by blood-sucking bugs. Prolactin level was lower during the renesting period, especially in birds which abandoned their clutch afterwards, whereas corticosterone did not change. Excluding the deserting birds, the reduced prolactin level was not linked to minor success, but could be related to seasonal processes. The control group of late laying common terns showed comparably low prolactin values, but increased corticosterone concentrations. Renesting individuals exhibited higher prolactin during incubation of their first clutch than non-renesting birds, probably indicating their higher quality. The fact that terns still have relatively high prolactin and low corticosterone values during renesting might confirm their higher quality and suggests that they are able to meet the costs of a second demanding breeding period without being considerably stressed.
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41
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Riechert J, Chastel O, Becker PH. Why do experienced birds reproduce better? Possible endocrine mechanisms in a long-lived seabird, the common tern. Gen Comp Endocrinol 2012; 178:391-9. [PMID: 22750538 DOI: 10.1016/j.ygcen.2012.06.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 06/19/2012] [Accepted: 06/20/2012] [Indexed: 11/18/2022]
Abstract
The influence of age or breeding experience on reproductive success in vertebrates is well known but physiological mechanisms came into focus just recently. Assessing hormone levels could allow insights into these mechanisms and reproductive strategies in long-lived species. Prolactin and corticosterone are two hormones involved in breeding decisions: high prolactin values are necessary for expressing breeding behavior whereas corticosterone is related to activity or stress. We analyzed baseline prolactin and corticosterone under field conditions in common terns (Sterna hirundo) between 2006 and 2010. We took 760 blood samples of 346 known birds 9-14 days after their clutch completion, obtained via blood-sucking bugs (Dipetalogaster maximus), a non-invasive method with negligible stress for the birds. Many individuals were sampled repeatedly during the study period allowing investigation of hormone change on individual level. Prolactin levels increased during the early breeding career, which was confirmed on individual level, whereas corticosterone levels increased mostly in experienced birds, more pronounced in males. Low hormone levels during the first years of breeding could indicate a reduced ability of the endocrine system to secret hormones or it might express a down-regulation to limit parental expenditure. Higher corticosterone values of males could be related to increased foraging activity. Amongst the oldest birds, prolactin seemed to increase in males but not in females. This possible consequence of female senescence might be compensated by high values of male mates. Body mass showed only a weak positive correlation with prolactin level and no correlation with corticosterone concentration.
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Affiliation(s)
- Juliane Riechert
- Institute of Avian Research, Vogelwarte Helgoland, An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.
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42
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Pittet F, Coignard M, Houdelier C, Richard-Yris MA, Lumineau S. Age affects the expression of maternal care and subsequent behavioural development of offspring in a precocial bird. PLoS One 2012; 7:e36835. [PMID: 22701515 PMCID: PMC3365116 DOI: 10.1371/journal.pone.0036835] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 04/07/2012] [Indexed: 11/23/2022] Open
Abstract
Variations of breeding success with age have been studied largely in iteroparous species and particularly in birds: survival of offspring increases with parental age until senescence. Nevertheless, these results are from observations of free-living individuals and therefore, it remains impossible to determine whether these variations result from parental investment or efficiency or both, and whether these variations occur during the prenatal or the postnatal stage or during both. Our study aimed first, to determine whether age had an impact on the expression of maternal breeding care by comparing inexperienced female birds of two different ages, and second, to define how these potential differences impact chicks’ growth and behavioural development. We made 22 2-month-old and 22 8-month-old female Japanese quail foster 1-day-old chicks. We observed their maternal behaviour until the chicks were 11 days old and then tested these chicks after separation from their mothers. Several behavioural tests estimated their fearfulness and their sociality. We observed first that a longer induction was required for young females to express maternal behaviour. Subsequently as many young females as elder females expressed maternal behaviour, but young females warmed chicks less, expressed less covering postures and rejected their chicks more. Chicks brooded by elder females presented higher growth rates and more fearfulness and sociality. Our results reveal that maternal investment increased with age independently of maternal experience, suggesting modification of hormone levels implied in maternal behaviour. Isolated effects of maternal experience should now be assessed in females of the same age. In addition, our results show, for first time in birds, that variations in maternal care directly induce important differences in the behavioural development of chicks. Finally, our results confirm that Japanese quail remains a great laboratory model of avian maternal behaviour and that the way we sample maternal behaviour is highly productive.
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Affiliation(s)
- Florent Pittet
- UMR 6552 Ethologie animale et humaine, CNRS-Université de Rennes 1, Rennes, France.
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Garamszegi LZ, Rosivall B, Rettenbacher S, Markó G, Zsebők S, Szöllősi E, Eens M, Potti J, Török J. Corticosterone, Avoidance of Novelty, Risk-Taking and Aggression in a Wild Bird: No Evidence for Pleiotropic Effects. Ethology 2012. [DOI: 10.1111/j.1439-0310.2012.02049.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | - Balázs Rosivall
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology; Eötvös Loránd University; Budapest; Hungary
| | - Sophie Rettenbacher
- Department of Biomedical Sciences, Biochemistry; University of Veterinary Medicine Vienna; Vienna; Austria
| | | | | | - Eszter Szöllősi
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology; Eötvös Loránd University; Budapest; Hungary
| | - Marcel Eens
- Department of Biology; University of Antwerp Wilrijk; Belgium
| | - Jaime Potti
- Department of Evolutionary Ecology; Estación Biológica de Doñana-CSIC; Seville; Spain
| | - János Török
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology; Eötvös Loránd University; Budapest; Hungary
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O’Connor CM, Barthel BL, Gilmour KM, Philipp DP, Van Der Kraak G, Cooke SJ. Reproductive History and Nest Environment Are Correlated with Circulating Androgen and Glucocorticoid Concentrations in a Parental Care–Providing Teleost Fish. Physiol Biochem Zool 2012; 85:209-18. [DOI: 10.1086/665272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Schmid B, Chastel O, Jenni L. The prolactin response to an acute stressor in relation to parental care and corticosterone in a short-lived bird, the Eurasian hoopoe. Gen Comp Endocrinol 2011; 174:22-9. [PMID: 21855546 DOI: 10.1016/j.ygcen.2011.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 07/19/2011] [Accepted: 07/27/2011] [Indexed: 11/26/2022]
Abstract
Prolactin plays an important role in mediating parental care in birds, but little is known about changes in prolactin levels when animals disrupt their reproductive behaviour during emergency life-history stages. We investigated the variation of prolactin levels with breeding stage, sex, body condition and as a response to a standardized acute stressor in a small short-lived bird, the Eurasian hoopoe Upupa epops under natural field conditions. We found higher baseline levels of prolactin in females during the brooding phase than in their mates which feed them and their chicks at this stage. Moreover, this is the first report of a differential prolactin stress-response between sexes with contrasting parental care within a breeding phase. Capture, handling and restraint induced a clear decrease of prolactin levels which was less pronounced in females at the very early stage of brooding compared to females in later stages. In contrast, the prolactin stress response in males remained nearly constant over the breeding stages and was stronger than in females. Baseline levels of prolactin, but not handling-induced levels, were positively correlated with body condition. We found a weak relationship between the decrease in prolactin due to acute handling stress and handling-induced levels of corticosterone. Taken together, both baseline and stress response levels of prolactin were related to the amount of parental care, although we found no relationship with reproductive success. It appears that the response to an acute stressor in prolactin levels is finely tuned to parental duties and investment. Hence, prolactin appears to be involved in mediating the trade-off between current reproduction versus self-maintenance and future reproduction.
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Affiliation(s)
- Baptiste Schmid
- Swiss Ornithological Institute, Seerose 1, CH-6204 Sempach, Switzerland.
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46
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Wilcoxen TE, Boughton RK, Bridge ES, Rensel MA, Schoech SJ. Age-related differences in baseline and stress-induced corticosterone in Florida scrub-jays. Gen Comp Endocrinol 2011; 173:461-6. [PMID: 21827761 DOI: 10.1016/j.ygcen.2011.07.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 06/22/2011] [Accepted: 07/22/2011] [Indexed: 11/17/2022]
Abstract
In physiological studies of free-living species, it is essential to consider the context of the life history stage at which an individual was observed in order to link measures of physiology with ecological parameters. One such measure that is important to consider is the age of an individual. We tested whether baseline or stress-induced corticosterone levels vary with age in free-living Florida scrub-jays (Aphelocoma coerulescens) during the pre-breeding period. Corticosterone (CORT), the primary avian stress hormone, is released in response to stressful stimuli, and stimulates gluconeogenesis; however, it also serves as a chemical messenger that can influence other physiological processes, reproduction, and behavior. We monitored both baseline CORT levels longitudinally throughout a five-year period and stress-induced CORT responses over a shorter two-year period. We predicted that older jays would have lower baseline CORT levels and a dampened stress response compared to younger birds, as has been shown in other avian species. We found no significant differences in baseline CORT levels with age. We found a decrease in total corticosterone responses to a stressor with age, however, the oldest birds in the population showed greater total corticosterone responses to a stressor. These results may be a product of age-related changes in physiological processes related to the stress response or a result of selection acting on the population, resulting in only the most responsive individuals surviving to old age.
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Affiliation(s)
- Travis E Wilcoxen
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA.
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Spée M, Marchal L, Lazin D, Le Maho Y, Chastel O, Beaulieu M, Raclot T. Exogenous corticosterone and nest abandonment: a study in a long-lived bird, the Adélie penguin. Horm Behav 2011; 60:362-70. [PMID: 21763694 DOI: 10.1016/j.yhbeh.2011.07.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 06/29/2011] [Accepted: 07/02/2011] [Indexed: 11/26/2022]
Abstract
Breeding individuals enter an emergency life-history stage when their body reserves reach a minimum threshold. Consequently, they redirect current activity toward survival, leading to egg abandonment in birds. Corticosterone (CORT) is known to promote this stage. How and to what extent CORT triggers egg abandonment when breeding is associated with prolonged fasting, however, requires further investigation. We manipulated free-living male Adélie penguins with CORT-pellets before their laying period. We then examined their behavioral response with respect to nest abandonment in parallel with their prolactin levels (regulating parental care), and the subsequent effects of treatment on breeding success in relieved birds. Exogenous CORT triggered nest abandonment in 60% of the treated penguins ~14 days after treatment and induced a concomitant decline in prolactin levels. Interestingly, prolactin levels in treated penguins that did not abandon their nest were higher at the point of implantation and also after being relieved by females, when compared with abandoning penguins. Among successful birds, the treatment did not affect the number of chicks, nor the brood mass. Our results show the involvement of CORT in the decision-making process regarding egg abandonment in Adélie penguins when incubation is associated with a natural long fast. However, we suggest that CORT alone is not sufficient to trigger nest abandonment but that 1) prolactin levels need to reach a low threshold value, and 2) a rise in proteolysis (i.e. utilization of protein as main energy substrate) seems also to be required.
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Affiliation(s)
- Marion Spée
- Université de Strasbourg, IPHC-DEPE, 23 rue Becquerel, 67087, Strasbourg, France.
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Selva N, Cortés-Avizanda A, Lemus JA, Blanco G, Mueller T, Heinrich B, Donázar JA. Stress associated with group living in a long-lived bird. Biol Lett 2011; 7:608-10. [PMID: 21307048 PMCID: PMC3130225 DOI: 10.1098/rsbl.2010.1204] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 01/18/2011] [Indexed: 11/12/2022] Open
Abstract
Many long-lived avian species adopt life strategies that involve a gregarious way of life at juvenile and sub-adult stages and territoriality during adulthood. However, the potential associated costs of these life styles, such as stress, are poorly understood. We examined the effects of group living, sex and parasite load on the baseline concentration of faecal stress hormone (corticosterone) metabolites in a wild population of common ravens (Corvus corax). Corticosterone concentrations were significantly higher in non-breeding gregarious ravens than in territorial adults. Among territorial birds, males showed higher stress levels than their mates. Parasite burdens did not affect hormone levels. Our results suggest a key role of the social context in the stress profiles of the two population fractions, and that group living may be more energetically demanding than maintaining a territory. These findings have implications for understanding hormonal mechanisms under different life styles and may inspire further research on the link between hormone levels and selective pressures modulating gregarious and territorial strategies in long-lived birds.
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Affiliation(s)
- Nuria Selva
- Institute of Nature Conservation PAS, Mickiewicza 33, 31120 Kraków, Poland.
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Ninnes CE, Waas JR, Ling N, Nakagawa S, Banks JC, Bell DG, Bright A, Carey PW, Chandler J, Hudson QJ, Ingram JR, Lyall K, Morgan DKJ, Stevens MI, Wallace J, Möstl E. Environmental influences on Adelie penguin breeding schedules, endocrinology, and chick survival. Gen Comp Endocrinol 2011; 173:139-47. [PMID: 21624370 DOI: 10.1016/j.ygcen.2011.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 04/09/2011] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
To understand how the social and physical environment influences behaviour, reproduction and survival, studies of underlying hormonal processes are crucial; in particular, interactions between stress and reproductive responses may have critical influences on breeding schedules. Several authors have examined the timing of breeding in relation to environmental stimuli, while others have independently described endocrine profiles. However, few studies have simultaneously measured endocrine profiles, breeding behaviour, and offspring survival across seasons. We measured sex and stress hormone concentrations (oestrogens, testosterone, and corticosterone), timing of breeding, and chick survival, in Adelie penguins (Pygoscelis adeliae) at two colonies in two different years. Clutch initiation at Cape Bird South (CBS; year 1, ~14,000 pairs) occurred later than at Cape Crozier East (CCE; year 2, ~ 25,000 pairs); however, breeding was more synchronous at CBS. This pattern was probably generated by the persistence of extensive sea ice at CBS (year 1). Higher corticosterone metabolite and lower sex hormone concentrations at CBS correlated with later breeding and lower chick survival compared to at CCE - again, a likely consequence of sea ice conditions. Within colonies, sub-colony size (S, 50-100; M, 200-300; L, 500-600; XL, >1000 pairs) did not influence the onset or synchrony of breeding, chick survival, or hormone concentrations. We showed that the endocrine profiles of breeding Adelie penguins can differ markedly between years and/or colonies, and that combining measures of endocrinology, behaviour, and offspring survival can reveal the mechanisms and consequences that different environmental conditions can have on breeding ecology.
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Affiliation(s)
- C E Ninnes
- Department of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand.
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Wingfield JC, Ramenofsky M. Hormone-Behavior Interrelationships of Birds in Response to Weather. ADVANCES IN THE STUDY OF BEHAVIOR 2011. [DOI: 10.1016/b978-0-12-380896-7.00003-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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