1
|
Apfelbeck B, Cousseau L, Kung’u GN, Canoine V, Heiskanen J, Korir DK, Lala F, Pellikka P, Githiru M, Lens L. Cooperative breeding alters physiological and behavioral responses to habitat fragmentation. iScience 2024; 27:108717. [PMID: 38299033 PMCID: PMC10829880 DOI: 10.1016/j.isci.2023.108717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/03/2023] [Accepted: 12/11/2023] [Indexed: 02/02/2024] Open
Abstract
Animals respond to habitat alteration with changes in their behavior and physiology. These changes determine individual performance and thus precede changes in population size. They are therefore hypothesized to provide important insights into how animals cope with environmental change. Here, we investigated physiological and behavioral responses of a cooperatively breeding bird, the placid greenbul (Phyllastrephus placidus), in a severely fragmented tropical biodiversity hotspot and combined these data with remotely sensed (LiDAR) environmental data. We found that individuals had increased glucocorticoid hormone levels when breeding in territories with low native canopy cover or located within small fragments. However, when breeding with the help of subordinates, breeders in low quality territories had similar glucocorticoid levels as those in higher quality territories. Our study shows that sociality may impact how well animals cope with environmental change and contributes to our understanding of the role of glucocorticoid physiology and behavior in response to anthropogenic change.
Collapse
Affiliation(s)
- Beate Apfelbeck
- Evolutionary Zoology Group, Department of Environment and Biodiversity, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Laurence Cousseau
- Terrestrial Ecology Unit, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Gladys Nyakeru Kung’u
- Evolutionary Zoology Group, Department of Environment and Biodiversity, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Virginie Canoine
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Janne Heiskanen
- Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
- Finnish Meteorological Institute, P.O. Box 503, 00101 Helsinki, Finland
| | - David K. Korir
- Wildlife Research and Training Institute, P.O. Box 842, Naivasha 20117, Kenya
| | - Fredrick Lala
- Wildlife Research and Training Institute, P.O. Box 842, Naivasha 20117, Kenya
| | - Petri Pellikka
- Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
- University of Nairobi, Wangari Maathai Institute for Environmental and Peace Studies, P.O. Box 29053, Kangemi 00625, Kenya
- State Key Laboratory for Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China
| | - Mwangi Githiru
- Wildlife Works, P.O. Box 310, Voi 80300, Kenya
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Luc Lens
- Terrestrial Ecology Unit, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
| |
Collapse
|
2
|
Rodríguez C, Fusani L, Raboisson G, Hödl W, Ringler E, Canoine V. Androgen responsiveness to simulated territorial intrusions in Allobates femoralis males: Evidence supporting the challenge hypothesis in a territorial frog. Gen Comp Endocrinol 2022; 326:114046. [PMID: 35472315 DOI: 10.1016/j.ygcen.2022.114046] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022]
Abstract
Territoriality has been widely described across many animal taxa, where the acquisition and defence of a territory are critical for the fitness of an individual. Extensive evidence suggests that androgens are involved in the modulation of territorial behaviours in male vertebrates. Short-term increase of androgen following a territorial encounter appears to favour the outcome of a challenge. The "Challenge Hypothesis" proposed by Wingfield and colleagues outlines the existence of a positive feedback relationship between androgen and social challenges (e.g., territorial intrusions) in male vertebrates. Here we tested the challenge hypothesis in the highly territorial poison frog, Allobates femoralis, in its natural habitat by exposing males to simulated territorial intrusions in the form of acoustic playbacks. We quantified repeatedly androgen concentrations of individual males via a non-invasive water-borne sampling approach. Our results show that A. femoralis males exhibited a positive behavioural and androgenic response after being confronted to simulated territorial intrusions, providing support for the Challenge Hypothesis in a territorial frog.
Collapse
Affiliation(s)
- Camilo Rodríguez
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria.
| | - Leonida Fusani
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria; Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Gaëlle Raboisson
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Walter Hödl
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Eva Ringler
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria; Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria; Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Virginie Canoine
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| |
Collapse
|
3
|
Zúñiga-Vega JJ, Pruett JA, Ossip-Drahos AG, Campos SM, Seddon RJ, Price SL, Romero-Diaz C, Rivera JA, Vital-García C, Hews DK, Martins EP. Information out of the blue: phenotypic correlates of abdominal color patches in Sceloporus lizards. ZOOLOGY 2021; 149:125961. [PMID: 34592493 DOI: 10.1016/j.zool.2021.125961] [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: 02/22/2021] [Revised: 08/12/2021] [Accepted: 08/19/2021] [Indexed: 11/28/2022]
Abstract
Colorful ornaments are important visual signals for animal communication that can provide critical information about the quality of the signaler. In this study, we focused on different color characteristics of the abdominal patches of males of six lizard species from the genus Sceloporus. We addressed three main objectives. First, we examined if size, brightness, saturation, and conspicuousness of these ornaments are indicative of body size, condition, immune function, or levels of testosterone and corticosterone. Second, we evaluated if the distinct components of these abdominal patches (blue or green patches and black stripes) transmit similar information about the signaler, which would support the redundant signal hypothesis, or if these components are related to different phenotypic traits, which would support the multiple message hypothesis. Third, we compared the phenotypic correlates of these ornaments among our six species to understand the degree of conservatism in the signaling patterns or to find species-specific signals. Using data collected from males in natural conditions and a multi-model inference framework, we found that in most species the area of the patches and the brightness of the blue component are positively related to body size. Thus, these color characteristics are presumably indicative of the physical strength and competitive ability of males and these shared signals were likely inherited from a common ancestor. In half of the species, males in good body condition also exhibit relatively larger blue and black areas, suggesting that the expression of these ornaments is condition-dependent. Abdominal patches also provide information about immunocompetence of the males as indicated by different correlations between certain color characteristics and ectoparasite load, counts of heterophils, and the heterophil:lymphocyte ratio. Our findings reveal that area and brightness of the abdominal patches signal the size and body condition of males, whereas blue saturation and conspicuousness with respect to the surrounding substrate are indicative of immune condition, thus supporting the multiple message hypothesis. However, some of these correlations were not shared by all species and, hence, point to intriguing species-specific signals.
Collapse
Affiliation(s)
- J Jaime Zúñiga-Vega
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Coyoacán, Mexico City, 04510, Mexico.
| | - Jake A Pruett
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA; Department of Biological Sciences, Southeastern Oklahoma State University, 425 W. University Boulevard, Durant, OK 74701, USA.
| | - Alison G Ossip-Drahos
- Department of Chemistry and Physical Sciences, Marian University, 3200 Cold Springs Road, Indianapolis, IN 46222, USA.
| | - Stephanie M Campos
- Biology Department, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
| | - Ryan J Seddon
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA; Center for Global Communication Strategies, University of Tokyo, 3-8-4 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
| | - Savannah L Price
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA.
| | - Cristina Romero-Diaz
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA.
| | - Julio A Rivera
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA.
| | - Cuauhcihuatl Vital-García
- Departamento de Ciencias Veterinarias, Universidad Autónoma de Ciudad Juárez, Anillo Envolvente y Estocolmo s/n, Colonia Progresista, Ciudad Juárez, Chihuahua, 32310, Mexico.
| | - Diana K Hews
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA.
| | - Emília P Martins
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA.
| |
Collapse
|
4
|
DeRango EJ, Schwarz JFL, Piedrahita P, Páez‐Rosas D, Crocker DE, Krüger O. Hormone-mediated foraging strategies in an uncertain environment: Insights into the at-sea behavior of a marine predator. Ecol Evol 2021; 11:7579-7590. [PMID: 34188836 PMCID: PMC8216952 DOI: 10.1002/ece3.7590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/22/2022] Open
Abstract
Hormones are extensively known to be physiological mediators of energy mobilization and allow animals to adjust behavioral performance in response to their environment, especially within a foraging context.Few studies, however, have narrowed focus toward the consistency of hormonal patterns and their impact on individual foraging behavior. Describing these relationships can further our understanding of how individuals cope with heterogeneous environments and exploit different ecological niches.To address this, we measured between- and within-individual variation of basal cortisol (CORT), thyroid hormone T3, and testosterone (TEST) levels in wild adult female Galápagos sea lions (Zalophus wollebaeki) and analyzed how these hormones may be associated with foraging strategies. In this marine predator, females exhibit one of three spatially and temporally distinct foraging patterns (i.e., "benthic," "pelagic," and "night" divers) within diverse habitat types.Night divers differentiated from other strategies by having lower T3 levels. Considering metabolic costs, night divers may represent an energetically conservative strategy with shorter dive durations, depths, and descent rates to exploit prey which migrate up the water column based on vertical diel patterns.Intriguingly, CORT and TEST levels were highest in benthic divers, a strategy characterized by congregating around limited, shallow seafloors to specialize on confined yet reliable prey. This pattern may reflect hormone-mediated behavioral responses to specific risks in these habitats, such as high competition with conspecifics, prey predictability, or greater risks of predation.Overall, our study highlights the collective effects of hormonal and ecological variation on marine foraging. In doing so, we provide insights into how mechanistic constraints and environmental pressures may facilitate individual specialization in adaptive behavior in wild populations.
Collapse
Affiliation(s)
| | | | - Paolo Piedrahita
- Facultad de Ciencias de la VidaEscuela Superior Politécnica del LitoralGuayaquilEcuador
| | - Diego Páez‐Rosas
- Universidad San Francisco de QuitoGalápagos Science CenterIsla San CristobalEcuador
- Dirección Parque Nacional GalápagosOficina Técnica San CristóbalIsla San CristóbalEcuador
| | | | - Oliver Krüger
- Department of Animal BehaviourBielefeld UniversityBielefeldGermany
| |
Collapse
|
5
|
Argaez V, Pruett JA, Seddon RJ, Solano-Zavaleta I, Hews DK, Zúñiga-Vega JJ. Steroid hormones, ectoparasites, and color: Sex, species, and seasonal differences in Sceloporus lizards. Gen Comp Endocrinol 2021; 304:113717. [PMID: 33476662 DOI: 10.1016/j.ygcen.2021.113717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 11/06/2020] [Accepted: 01/14/2021] [Indexed: 12/20/2022]
Abstract
Testosterone, in addition to promoting the expression of sexual ornaments can negatively affect immune function, leaving individuals more susceptible to parasites (immunocompetence handicap hypothesis). Immunosuppressive effects of testosterone also can occur indirectly, through increased glucocorticoid hormones (corticosterone, cortisol). Therefore, the expression of sexual ornaments and the ability to respond to parasites and diseases may be influenced by the interaction between testosterone and corticosterone. In this study we examined correlations of both testosterone and corticosterone with ectoparasite load and with expression of colorful sexual ornaments (patches on belly and throat) in three species of Sceloporus lizards (S. grammicus, S. megalepidurus, S. torquatus). In addition, we evaluated contributions of sex, body condition, and reproductive season. We expected that individuals with higher testosterone and lower corticosterone levels would have more colorful ornaments than individuals with higher corticosterone levels. In addition, if testosterone has negative effects on immune function but only at higher corticosterone levels, individuals with higher levels of testosterone and corticosterone should have higher ectoparasite loads. Contrary to these expectations, we did not detect an interaction between testosterone and corticosterone statistically affecting either ectoparasite load or the expression of colorful ornaments. Further, we did not find a positive association of either testosterone or corticosterone on ectoparasite loads in any of the three study species. Only in S. grammicus males was a hormone statistically associated with ectoparasite load, but it was a negative association with testosterone. The relationships between both hormones and different aspects of the colorful patches (brightness and chroma) varied drastically among the three species as well as between sexes. Hence, even among congeneric species, we did not observe consistent patterns among color, steroid hormones and ectoparasites. Different associations between these variables may reflect different physiological strategies for the production of colorful signals and immune defense.
Collapse
Affiliation(s)
- Víctor Argaez
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
| | - Jake A Pruett
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA; Department of Biological Sciences, Southeastern Oklahoma State University, Durant, OK 74701, USA.
| | - Ryan J Seddon
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - Israel Solano-Zavaleta
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
| | - Diana K Hews
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - J Jaime Zúñiga-Vega
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
| |
Collapse
|
6
|
Dakin R, Moore IT, Horton BM, Vernasco BJ, Ryder TB. Testosterone-mediated behaviour shapes the emergent properties of social networks. J Anim Ecol 2020; 90:131-142. [PMID: 32745255 DOI: 10.1111/1365-2656.13305] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/07/2020] [Indexed: 12/20/2022]
Abstract
Social networks can vary in their organization and dynamics, with implications for ecological and evolutionary processes. Understanding the mechanisms that drive social network dynamics requires integrating individual-level biology with comparisons across multiple social networks. Testosterone is a key mediator of vertebrate social behaviour and can influence how individuals interact with social partners. Although the effects of testosterone on individual behaviour are well established, no study has examined whether hormone-mediated behaviour can scale up to shape the emergent properties of social networks. We investigated the relationship between testosterone and social network dynamics in the wire-tailed manakin, a lekking bird species in which male-male social interactions form complex social networks. We used an automated proximity system to longitudinally monitor several leks and we quantified the social network structure at each lek. Our analysis examines three emergent properties of the networks-social specialization (the extent to which a network is partitioned into exclusive partnerships), network stability (the overall persistence of partnerships through time) and behavioural assortment (the tendency for like to associate with like). All three properties are expected to promote the evolution of cooperation. As the predictor, we analysed the collective testosterone of males within each social network. Social networks that were composed of high-testosterone dominant males were less specialized, less stable and had more negative behavioural assortment, after accounting for other factors. These results support our main hypothesis that individual-level hormone physiology can predict group-level network dynamics. We also observed that larger leks with more interacting individuals had more positive behavioural assortment, suggesting that small groups may constrain the processes of homophily and behaviour-matching. Overall, these results provide evidence that hormone-mediated behaviour can shape the broader architecture of social groups. Groups with high average testosterone exhibit social network properties that are predicted to impede the evolution of cooperation.
Collapse
Affiliation(s)
- Roslyn Dakin
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, USA.,Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Brent M Horton
- Department of Biology, Millersville University, Millersville, PA, USA
| | - Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - T Brandt Ryder
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, USA.,Bird Conservancy of the Rockies, Fort Collins, CO, USA
| |
Collapse
|
7
|
Huffeldt NP, Merkel FR, Jenni-Eiermann S, Goymann W, Helm B. Melatonin and corticosterone profiles under polar day in a seabird with sexually opposite activity-rhythms. Gen Comp Endocrinol 2020; 285:113296. [PMID: 31589833 DOI: 10.1016/j.ygcen.2019.113296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 11/27/2022]
Abstract
The 24 h geophysical light-dark cycle is the main organizer of daily rhythms, scheduling physiology and behavior. This cycle attenuates greatly during the continuous light of summer at polar latitudes, resulting in species-specific and even individual-specific patterns of behavioral rhythmicity, but the physiological mechanisms underlying this variation are poorly understood. To address this knowledge gap and to better understand the roles of the hormones melatonin and corticosterone in rhythmic behavior during this 'polar day', we exploited the behavior of thick-billed murres (Uria lomvia), a charadriiform seabird with sexually opposite ('antiphase') activity-rhythms that have a duration of 24 h. Melatonin concentration in the plasma of inactive males was unexpectedly high around midday and subsequently fell during a sudden decrease in light intensity as the colony became shaded. Corticosterone concentration in plasma did not vary with time of day or activity in either sex. While the reasons for these unusual patterns remain unclear, we propose that a flexible melatonin response and little diel variation of corticosterone may be adaptive in thick-billed murres, and perhaps other polar birds and mammals, by stabilizing glucocorticoids' role of modulating energy storage and mobilization across the diel cycle and facilitating the appropriate reaction to unexpected stimuli experienced across the diel cycle while attending the colony.
Collapse
Affiliation(s)
| | - Flemming R Merkel
- Department of Bioscience, Aarhus University, DK-4000 Roskilde, Denmark; Greenland Institute of Natural Resources, DK-3900 Nuuk, Greenland
| | | | - Wolfgang Goymann
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, D-82319 Seewiesen, Germany
| | - Barbara Helm
- IBAHCM, University of Glasgow, Glasgow G12 8QQ, United Kingdom; Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, 9747 AG Groningen, Netherlands
| |
Collapse
|
8
|
Ryder TB, Dakin R, Vernasco BJ, Evans BS, Horton BM, Moore IT. Testosterone Modulates Status-Specific Patterns of Cooperation in a Social Network. Am Nat 2020; 195:82-94. [DOI: 10.1086/706236] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
9
|
Vernasco BJ, Horton BM, Moore IT, Ryder TB. Reduced cooperative behavior as a cost of high testosterone in a lekking passerine bird. Behav Ecol 2019. [DOI: 10.1093/beheco/arz201] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Abstract
Many studies have identified the reproductive benefits of cooperative behaviors, yet few have identified the mechanisms that underlie these behaviors. Mechanistic studies can inform our understanding of why some individuals are more or less cooperative, as well as identify the physiological constraints imposed upon the evolution of reproductive traits. Male wire-tailed manakins (Pipra filicauda) exhibit cooperative courtship behaviors and more cooperative territory holders have been shown to exhibit higher reproductive success. To begin to understand the proximate basis of cooperative display behaviors, we conducted both an observational study and an experimental study. Because coordinated courtship displays underlie this form of cooperation, our study also examined both the hormonal and social drivers of individual variation in courtship behavior more broadly (e.g., courtship display rates). Our observational study revealed that males with higher testosterone levels performed fewer cooperative display bouts. In addition, our experimental study demonstrated that the proportion of a male’s courtship displays that were cooperative decreased after being administered a testosterone-filled hormone implant. We found no relationship between an individual’s courtship display effort (i.e., display rate and time spent performing courtship displays) and circulating testosterone in either study. However, more cooperative males spent a greater proportion of time performing courtship displays than did less cooperative males, suggesting that testosterone may indirectly mediate courtship display behaviors by influencing a territory holder’s cooperative behavior. Overall, both our observational and experimental results suggest that reduced cooperative behavior is a cost of maintaining high levels of testosterone for territory-holding males.
Collapse
Affiliation(s)
- Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Brent M Horton
- Department of Biology, Millersville University, Millersville, PA, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - T Brandt Ryder
- Migratory Bird Center, Smithsonian Conservation Biology Institute,, Washington DC, USA
| |
Collapse
|
10
|
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.
Collapse
|
11
|
Vernasco BJ, Horton BM, Ryder TB, Moore IT. Sampling baseline androgens in free-living passerines: Methodological considerations and solutions. Gen Comp Endocrinol 2019; 273:202-208. [PMID: 30056137 DOI: 10.1016/j.ygcen.2018.07.017] [Citation(s) in RCA: 12] [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: 02/27/2018] [Revised: 07/18/2018] [Accepted: 07/25/2018] [Indexed: 12/28/2022]
Abstract
Obtaining baseline hormone samples can be challenging because circulating hormone levels often change rapidly due to the acute stress of capture. Although field protocols are established for accurately sampling baseline glucocorticoid concentrations, fewer studies have examined how common sampling techniques affect androgens levels. Indeed, many studies focused on understanding the functional significance of baseline androgen levels use sampling methods known to activate the endocrine responses to stress. To understand how different field sampling protocols affect plasma androgen levels, we measured the androgen response to two types of capture stressors in a free-living tropical bird, the wire-tailed manakin (Pipra filicauda). First, we subjected males to a standardized capture and restraint protocol lasting either 15 or 30 min. Second, males were passively captured in nets that were filmed (to establish exact duration of time between capture and blood sampling) and checked every 30 min. The first study showed that circulating plasma androgen levels decreased significantly following both 15 and 30 min of restraint in a cloth bag, with a trend for the 30 min samples to be lower than the 15 min samples. Further, the change in androgen levels was dependent on an individual's initial androgen levels, with the individuals with the highest initial levels registering the largest declines. The results of the second study suggest that hanging in a mist net for extended periods of time also leads to a decrease in circulating androgen levels, but this effect was weaker than that of capture and restraint in a cloth bag. Our findings demonstrate that, overall, circulating androgen levels decrease in response to common sampling techniques; a finding that has important implications for studies measuring baseline androgen levels in free-living birds. Future studies should prioritize sampling individuals immediately upon removal from the mist net, as handling and restraint have a strong negative effect on circulating androgen levels. When constant monitoring of the mist net is not possible, investigators should use video cameras to record the amount of time an individual spends in the net prior to blood sampling and then statistically control for the effect of this variable in analyses.
Collapse
Affiliation(s)
- Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Brent M Horton
- Department of Biology, Millersville University, Millersville, PA 17551, USA
| | - T Brandt Ryder
- Migratory Bird Center, Smithsonian Conservation Biology Institute, Washington, DC, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| |
Collapse
|
12
|
Ovid D, Hayes TB, Bentley GE. Melatonin Administration Methods for Research in Mammals and Birds. J Biol Rhythms 2018; 33:567-588. [PMID: 30246597 DOI: 10.1177/0748730418795802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Endocrine research in animals often entails exogenous hormone administration. Special issues arise when developing administration protocols for hormones with circadian and seasonal periodicity. This article reviews various methods for the exogenous administration of hormones with such periodicities by focusing on melatonin. We discuss that methodological variations across studies can affect experimental results. Melatonin administration techniques used in vertebrates includes infusion pumps, beeswax pellets, oral administration, injections, SILASTIC capsules, osmotic pumps, transdermal delivery, beads, and sponges.
Collapse
Affiliation(s)
- Dax Ovid
- University of California, Berkeley, CA, USA
| | | | | |
Collapse
|
13
|
Enbody ED, Boersma J, Schwabl H, Karubian J. Female ornamentation is associated with elevated aggression and testosterone in a tropical songbird. Behav Ecol 2018. [DOI: 10.1093/beheco/ary079] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Erik D Enbody
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| | - Jordan Boersma
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Hubert Schwabl
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Jordan Karubian
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| |
Collapse
|
14
|
Seddon RJ, Hews DK. Correlates of melanization in multiple high- and low-elevation populations of the lizard,Sceloporus occidentalis: Behavior, hormones, and parasites. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 327:481-492. [DOI: 10.1002/jez.2133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 10/21/2017] [Accepted: 10/30/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Ryan J. Seddon
- Department of Biology; Indiana State University; Terre Haute Indiana
| | - Diana K. Hews
- Department of Biology; Indiana State University; Terre Haute Indiana
| |
Collapse
|
15
|
Apfelbeck B, Helm B, Illera JC, Mortega KG, Smiddy P, Evans NP. Baseline and stress-induced levels of corticosterone in male and female Afrotropical and European temperate stonechats during breeding. BMC Evol Biol 2017; 17:114. [PMID: 28532466 PMCID: PMC5441054 DOI: 10.1186/s12862-017-0960-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 05/08/2017] [Indexed: 11/18/2022] Open
Abstract
Background Latitudinal variation in avian life histories falls along a slow-fast pace of life continuum: tropical species produce small clutches, but have a high survival probability, while in temperate species the opposite pattern is found. This study investigated whether differential investment into reproduction and survival of tropical and temperate species is paralleled by differences in the secretion of the vertebrate hormone corticosterone (CORT). Depending on circulating concentrations, CORT can both act as a metabolic (low to medium levels) and a stress hormone (high levels) and, thereby, influence reproductive decisions. Baseline and stress-induced CORT was measured across sequential stages of the breeding season in males and females of closely related taxa of stonechats (Saxicola spp) from a wide distribution area. We compared stonechats from 13 sites, representing Canary Islands, European temperate and East African tropical areas. Stonechats are highly seasonal breeders at all these sites, but vary between tropical and temperate regions with regard to reproductive investment and presumably also survival. Results In accordance with life-history theory, during parental stages, post-capture (baseline) CORT was overall lower in tropical than in temperate stonechats. However, during mating stages, tropical males had elevated post-capture (baseline) CORT concentrations, which did not differ from those of temperate males. Female and male mates of a pair showed correlated levels of post-capture CORT when sampled after simulated territorial intrusions. In contrast to the hypothesis that species with low reproduction and high annual survival should be more risk-sensitive, tropical stonechats had lower stress-induced CORT concentrations than temperate stonechats. We also found relatively high post-capture (baseline) and stress-induced CORT concentrations, in slow-paced Canary Islands stonechats. Conclusions Our data support and refine the view that baseline CORT facilitates energetically demanding activities in males and females and reflects investment into reproduction. Low parental workload was associated with lower post-capture (baseline) CORT as expected for a slow pace of life in tropical species. On a finer resolution, however, this tropical-temperate contrast did not generally hold. Post-capture (baseline) CORT was higher during mating stages in particular in tropical males, possibly to support the energetic needs of mate-guarding. Counter to predictions based on life history theory, our data do not confirm the hypothesis that long-lived tropical populations have higher stress-induced CORT concentrations than short-lived temperate populations. Instead, in the predator-rich tropical environments of African stonechats, a dampened stress response during parental stages may increase survival probabilities of young. Overall our data further support an association between life history and baseline CORT, but challenge the role of stress-induced CORT as a mediator of tropical-temperate variation in life history. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0960-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Beate Apfelbeck
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, G12 8QQ, UK. .,Terrestrial Ecology Research Group, Department of Ecology and Ecosystemmanagement, Technische Universität München, School of Life Sciences Weihenstephan, D-85354, Freising, Germany.
| | - Barbara Helm
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, G12 8QQ, UK
| | - Juan Carlos Illera
- Research Unit of Biodiversity (UO-CSIC-PA), Oviedo University, Campus of Mieres, 33600, Mieres, Spain
| | - Kim G Mortega
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, G12 8QQ, UK.,Department of Migration and Immunoecology, Max-Planck-Institut für Ornithologie, D-78315, Radolfzell, Germany
| | - Patrick Smiddy
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, T12 YN60, Ireland
| | - Neil P Evans
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, G12 8QQ, UK
| |
Collapse
|
16
|
Apfelbeck B, Mortega KG, Flinks H, Illera JC, Helm B. Testosterone, territorial response, and song in seasonally breeding tropical and temperate stonechats. BMC Evol Biol 2017; 17:101. [PMID: 28412929 PMCID: PMC5392926 DOI: 10.1186/s12862-017-0944-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/23/2017] [Indexed: 11/23/2022] Open
Abstract
Background Testosterone facilitates physiological, morphological, and behavioral changes required for breeding in male vertebrates. However, testosterone concentrations and the link between its seasonal changes and those in reproductive behaviors vary greatly among species. To better understand the impact of tropical and temperate environments and life history factors on this variation, we have compared testosterone, territorial behavior and song performance across sequential stages of the breeding season in males of 16 closely related taxa of East African tropical and West European temperate stonechats (Saxicola spp), which all breed during a short breeding season, but differ in migratory behavior, seasonal territory-acquisition and pace of life. Results We found that generally, the profiles of testosterone and territorial behavior were similar across latitudes. African stonechats with a slow pace of life had equally high peak testosterone concentrations and responded as aggressively to an intruder as European stonechats with a fast pace of life. However, song performance at the beginning of the breeding season was lower in African than in European stonechats. The differences in song performance were not associated with variation in testosterone levels between tropical and temperate stonechats. Conclusions The results suggest a very similar role for testosterone as a mediator of high intensity territorial aggression during the fertile period of females in tropical and temperate stonechats, which all are highly seasonal, locally synchronous breeders. A potential explanation may be high risk of extra-pair copulations which has been associated with synchronous breeding. Interestingly, an association was not consistent for song performance. Our data suggest that song performance can be disassociated from peak testosterone levels depending on its role in breeding behavior. Despite similar testosterone levels, European males, which early in the breeding season acquire territories and mates, showed greater song performance than African stonechats, which maintain year-round territories and pair-bonds. Taken together, our study comparing related taxa of old world songbirds suggests that short breeding seasons may be a major selective force for high peak testosterone levels during breeding regardless of latitude and pace of life, but that particular behaviors, in our case song, can be uncoupled from peak testosterone levels. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0944-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Beate Apfelbeck
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, G12 8QQ, UK. .,Terrestrial Ecology Research Group, Department of Ecology and Ecosystemmanagement, Technische Universität München, School of Life Sciences Weihenstephan, D-85354, Freising, Germany.
| | - Kim G Mortega
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, G12 8QQ, UK.,Department of Migration and Immunoecology, Max-Planck-Institut für Ornithologie, D-78315 Radolfzell, Germany
| | | | - Juan Carlos Illera
- Research Unit of Biodiversity (UO-CSIC-PA), Oviedo University, Campus of Mieres, 33600, Mieres, Spain
| | - Barbara Helm
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, G12 8QQ, UK
| |
Collapse
|
17
|
Apfelbeck B, Flinks H, Goymann W. Territorial aggression does not feed back on testosterone in a multiple-brooded songbird species with breeding and non-breeding season territoriality, the European stonechat. Horm Behav 2017; 87:89-95. [PMID: 27838361 DOI: 10.1016/j.yhbeh.2016.11.002] [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: 05/03/2016] [Revised: 11/04/2016] [Accepted: 11/04/2016] [Indexed: 11/20/2022]
Abstract
Testosterone mediates reproductive behaviours in male vertebrates. For example, breeding season territoriality depends on testosterone in many species of birds and in some, territorial interactions feed back on testosterone concentrations. However, the degree to which territorial behaviour and testosterone are associated differs even between species with seemingly similar life histories, especially between species that also defend territories outside the breeding season. Here, we investigate the link between territorial behaviour and testosterone in European stonechats. Previous studies found that territorial aggression in stonechats depends on testosterone in a breeding, but not in a non-breeding context. We investigated whether stonechats show a rise in testosterone during simulated territorial intrusions (STI) during the breeding season. Post-capture testosterone concentrations of males caught after an STI were not higher than those of males caught in a control situation regardless of breeding stage. However, most of the males would have been able to mount a testosterone response because the same individuals that did not increase testosterone during the STI showed a substantial increase in testosterone after injections of gonadotropin-releasing hormone (GnRH). GnRH-induced and post-capture testosterone concentrations were positively correlated and both decreased with successive breeding stages. Further, territory owners with a short latency to attack the decoy expressed higher post-capture testosterone concentrations than males with a longer latency to attack the decoy. Thus, there is no evidence for behavioural feedback on testosterone concentrations during male-male interactions in stonechats. In combination with previous studies our data suggest that testosterone functions as an on/off switch of high intensity territorial aggression during the breeding season in stonechats. The among-species variation in the androgen control of territorial behaviour may be only partly a result of environmental differences. Instead, potential differences in how territoriality evolved in different species may have influenced whether and how a reproductive hormone such as testosterone was co-opted into the mechanistic control of territorial behaviour.
Collapse
Affiliation(s)
- Beate Apfelbeck
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Straße 6a, D-82319 Seewiesen, Germany; Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK; Department of Ecology and Ecosystem management, Technische Universität München, D-85354 Freising, Germany.
| | | | - Wolfgang Goymann
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Straße 6a, D-82319 Seewiesen, Germany
| |
Collapse
|
18
|
Populations of the Lizard,Sceloporus occidentalis, that Differ in Melanization have Different Rates of Wound Healing. ACTA ACUST UNITED AC 2016; 325:491-500. [DOI: 10.1002/jez.2033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/23/2016] [Accepted: 06/28/2016] [Indexed: 11/07/2022]
|
19
|
Seddon RJ, Hews DK. Phenotypic correlates of melanization in two Sceloporus occidentalis (Phrynosomatidae) populations: Behavior, androgens, stress reactivity, and ectoparasites. Physiol Behav 2016; 163:70-80. [PMID: 27137079 DOI: 10.1016/j.physbeh.2016.04.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 04/04/2016] [Accepted: 04/22/2016] [Indexed: 11/19/2022]
Abstract
Mechanisms underlying production of animal coloration can affect key traits besides coloration. Melanin, and molecules regulating melanin, can directly and indirectly affect other phenotypic traits including aggression, stress-reactivity, and immune function. We studied correlation of melanization with these other traits, comparing within- and between-population differences of adult male western fence lizards, Sceloporus occidentalis. We compared one high- and one low-elevation population in California where individuals are increasingly darker at higher elevations, working during comparable periods of the breeding season at each site (first egg clutch). We measured agonistic behaviors of free-ranging males in response to staged territorial intrusions (STIs). In other sets of males we measured baseline testosterone and corticosterone levels, and hormonal-reactivity to a stress handling paradigm. We counted ectoparasite loads for all males. There were no significant associations between individual variation in melanization and individual variation in any of the variables measured. However, analysis of behavior from the STIs revealed that males in the darker high-elevation population responded with more aggressive behavior compared to males in the lighter low-elevation population. Males in the low-elevation population had significantly higher mean baseline testosterone, but the two populations did not differ in adrenal function (baseline corticosterone or corticosterone after 1-h confinement stress). Males in the darker high-elevation population had higher mean mite loads compared to males in the lighter population. This array of phenotypic differences between the two populations, and the absence of trait associations when assessing individual variation, do not parallel the patterns in other vertebrates. We describe potential differences in selective regimes that could produce these different patterns across vertebrates. These data suggest that hormonal pleiotropy does not constrain phenotypic variation.
Collapse
Affiliation(s)
- Ryan J Seddon
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - Diana K Hews
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA
| |
Collapse
|
20
|
Apfelbeck B, Flinks H, Goymann W. Variation in Circulating Testosterone during Mating Predicts Reproductive Success in a Wild Songbird. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
21
|
Schwabl P, Bonaccorso E, Goymann W. Diurnal variation in corticosterone release among wild tropical forest birds. Front Zool 2016; 13:19. [PMID: 27152116 PMCID: PMC4857432 DOI: 10.1186/s12983-016-0151-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 04/28/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glucocorticoids are adrenal steroid hormones essential to homeostatic maintenance. Their daily variation at low concentrations regulates physiology and behavior to sustain proper immunological and metabolic function. Glucocorticoids rise well above these baseline levels during stress to elicit emergency-state responses that increase short-term survival. Despite this essence in managing life processes under both regular and adverse conditions, relationships of glucocorticoid release to environmental and intrinsic factors that vary at daily and seasonal scales are rarely studied in the wild. METHODS This study on 41 passerine species of the Ecuadorian Chocó applied a standardized capture-and-restraint protocol to examine diurnal variation in baseline and stress-related release of corticosterone, the primary avian glucocorticoid. Tests for relationships to relative body mass, hemoglobin concentration, molt status and date complemented this evaluation of the time of day effect on corticosterone secretion in free-living tropical rainforest birds. Analyses were also partitioned by sex as well as performed separately on two common species, the wedge-billed woodcreeper and olive-striped flycatcher. RESULTS Interspecific analyses indicated maximum baseline corticosterone levels at the onset of the active phase and reductions thereafter. Stress-related levels did not correspond to time of day but accompanied baseline reductions during molt and elevations in birds sampled later during the September - November study period. Baseline corticosterone related negatively to hemoglobin in the wedge-billed woodcreeper and stress-related levels increased with body mass in the olive-striped flycatcher. There were no substantial sex-related differences. CONCLUSIONS The results of this study suggest a diurnal rhythmicity in baseline corticosterone release so robust as to emerge in pooled analyses across a highly variable dataset. While this detection in nature is singular, correspondent patterns have been demonstrated outside of the tropics in captive model species. Congruity in daily rhythms and links to physiological and life-history state across disparate taxa and environments may promote the yet unresolved utility of corticosterone release as a global metric for population health. However, certain results of this study also deviate from laboratory and field research at higher latitudes, cautioning generalization. Environmental distinctions such as high productivity and tempered seasonality may precipitate unique life-history strategies and underlying hormonal mechanisms in tropical rainforest birds.
Collapse
Affiliation(s)
- Philipp Schwabl
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ UK
| | - Elisa Bonaccorso
- Centro para la Investigación de la Biodiversidad y Cambio Climático, Universidad Tecnológica Indoamérica, Machala y Sabanilla, Cotocollao, Quito, Ecuador
| | - Wolfgang Goymann
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str. 6a, D-82319 Seewiesen, Germany
| |
Collapse
|
22
|
Seltmann S, Trost L, Ter Maat A, Gahr M. Natural melatonin fluctuation and its minimally invasive simulation in the zebra finch. PeerJ 2016; 4:e1939. [PMID: 27123378 PMCID: PMC4846806 DOI: 10.7717/peerj.1939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/24/2016] [Indexed: 11/30/2022] Open
Abstract
Melatonin is a key hormone in the regulation of circadian rhythms of vertebrates, including songbirds. Understanding diurnal melatonin fluctuations and being able to reverse or simulate natural melatonin levels are critical to investigating the influence of melatonin on various behaviors such as singing in birds. Here we give a detailed overview of natural fluctuations in plasma melatonin concentration throughout the night in the zebra finch. As shown in previous studies, we confirm that “lights off” initiates melatonin production at night in a natural situation. Notably, we find that melatonin levels return to daytime levels as early as two hours prior to the end of the dark-phase in some individuals and 30 min before “lights on” in all animals, suggesting that the presence of light in the morning is not essential for cessation of melatonin production in zebra finches. Thus, the duration of melatonin production seems not to be specified by the length of night and might therefore be less likely to directly couple circadian and annual rhythms. Additionally, we show that natural melatonin levels can be successfully simulated through a combination of light-treatment (daytime levels during subjective night) and the application of melatonin containing skin-cream (nighttime levels during subjective day). Moreover, natural levels and their fluctuation in the transition from day to night can be imitated, enabling the decoupling of the effects of melatonin, for example on neuronal activity, from sleep and circadian rhythmicity. Taken together, our high-resolution profile of natural melatonin levels and manipulation techniques open up new possibilities to answer various melatonin related questions in songbirds.
Collapse
Affiliation(s)
- Susanne Seltmann
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology , Seewiesen , Germany
| | - Lisa Trost
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology , Seewiesen , Germany
| | - Andries Ter Maat
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology , Seewiesen , Germany
| | - Manfred Gahr
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology , Seewiesen , Germany
| |
Collapse
|
23
|
Goymann W, Villavicencio CP, Apfelbeck B. Does a short-term increase in testosterone affect the intensity or persistence of territorial aggression? - An approach using an individual's hormonal reactive scope to study hormonal effects on behavior. Physiol Behav 2015; 149:310-6. [PMID: 26122036 DOI: 10.1016/j.physbeh.2015.06.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 06/18/2015] [Accepted: 06/20/2015] [Indexed: 11/24/2022]
Abstract
In this study, we describe an approach based on an individual's hormonal reactive scope to study short-term effects of hormones on behavior. The control of territorial aggression has been traditionally linked to testosterone. Males of some vertebrate species show an increase in testosterone during territorial interactions and implantation studies suggest that such an increase in testosterone enhances the intensity and persistence of aggression. Here, we tested whether a short-term maximum release of testosterone - based on an individual's hormonal reactive scope - affects the intensity or persistence of territorial aggression in male black redstarts, a bird species in which testosterone does not increase during territorial encounters. An injection with gonadotropin-releasing-hormone (GnRH) induced a physiological peak in plasma testosterone that was specific for each individual (=individual reactive scope). However, such short-term surges in an individual's testosterone concentration did not affect the intensity or persistence of aggression. In conclusion, this study demonstrated (1) that a species that naturally does not increase testosterone during male-male encounters would not benefit from such an increase in terms of being more aggressive, (2) that behavioral studies using GnRH-injections represent a promising approach to study species differences in androgen responsiveness, and (3) that injections of releasing or tropic hormones in general may be a suitable approach to study short-term influences of hormones on behavior. These injections effectively mimic the potential short-term changes in hormones that can occur in the real life of individuals and enable us to study the effects of hormonal changes on behavior or other traits within an ecological and evolutionary framework.
Collapse
Affiliation(s)
- Wolfgang Goymann
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Straße 6a, D-82319 Seewiesen, Germany.
| | - Camila P Villavicencio
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Straße 6a, D-82319 Seewiesen, Germany
| | - Beate Apfelbeck
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Straße 6a, D-82319 Seewiesen, Germany; Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| |
Collapse
|
24
|
Grace JK, Anderson DJ. Corticosterone stress response shows long-term repeatability and links to personality in free-living Nazca boobies. Gen Comp Endocrinol 2014; 208:39-48. [PMID: 25220912 DOI: 10.1016/j.ygcen.2014.08.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/26/2014] [Accepted: 08/30/2014] [Indexed: 11/19/2022]
Abstract
The concept of "coping styles", or consistently different responses to stressors, is of broad interest in behavioral ecology and biomedicine. Two critical predictions of this concept are individual consistency of neurophysiological and behavioral responses (relative to population variability) and a negative relationship between aggression/proactivity and hypothalamic-pituitary-adrenal axis reactivity. Recent studies failed to provide strong support for these predictions, especially outside of strictly controlled conditions, and long-term measures to test the first prediction are rare. Here, we demonstrate individual repeatability across 2-3years of maximum circulating corticosterone concentration [CORT] and area under the [CORT] response curve (AUCI) during a standard capture-restraint test in wild, free-living adult Nazca boobies (Sula granti). We also show that the stress response predicts the personality traits aggression and anxiety in these birds (measured in the wild); however, the strength of these results was weak. Maximum [CORT] and AUCI showed higher repeatability between years than baseline [CORT]. After controlling breeding status, sex, mass, date sampled, and their interactions, baseline [CORT] was most closely related to personality traits, followed by AUCI, and then maximum [CORT]. The direction of these relationships depended on whether the testing context was social or non-social. [CORT] parameters had little to no relationship with cross-context plasticity in personality traits. Our results generally affirm two critical predictions of coping styles, but match the emerging trend that these relationships are weak in the wild, and may depend on testing context.
Collapse
Affiliation(s)
- Jacquelyn K Grace
- Dept. of Biology, Wake Forest University, Winston-Salem, NC 27106, USA.
| | - David J Anderson
- Dept. of Biology, Wake Forest University, Winston-Salem, NC 27106, USA
| |
Collapse
|
25
|
Villavicencio CP, Blas J, Goymann W. The number of life-history stages does not influence the androgen responsiveness to male-male interactions: sedentary and migratory black redstarts (Phoenicurus ochruros) do not elevate testosterone in response to simulated territorial intrusions. Gen Comp Endocrinol 2014; 205:159-65. [PMID: 24792820 DOI: 10.1016/j.ygcen.2014.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/20/2014] [Accepted: 04/14/2014] [Indexed: 11/25/2022]
Abstract
High plasma levels of testosterone at the beginning of the breeding season adjust male physiology for mating and promote territorial behavior in birds. Conversely intra-sexual competition may elicit a temporary increase in circulating testosterone. Male black redstarts (Phoenicurus ochruros) from migratory populations show the expected increase in baseline testosterone during early breeding, but circulating testosterone levels do not change in response to male-male interactions. Because sedentary populations express fewer life-history stages they may be more flexible in timing of life-history stages and more responsive to environmental modulation of hormone concentrations. Therefore, we tested whether the androgen responsiveness to male-male interactions differs between migratory (6 life-history stages) and sedentary black redstarts (3 life-history stages) during early breeding, predicting that in contrast to migratory birds, sedentary birds would modulate testosterone in response to simulated territorial intrusions (STI). In contrast to our prediction, sedentary males did not modulate post-capture testosterone levels in response to simulated territorial intrusions. Males of both populations increased testosterone after an injection of gonadotropin releasing hormone (GnRH), demonstrating that they were capable of increasing testosterone. Interestingly, in sedentary males the GnRH injection elicited a higher testosterone response in STI males than in control males. The two populations did not differ in their behavioral response to the STIs, except that sedentary males spent less time close to the decoy. In combination with previous data from black redstarts and other socially monogamous and biparental birds our current study adds to the growing evidence that current theory regarding hormone-behavior relationship needs to be refined.
Collapse
Affiliation(s)
- C P Villavicencio
- Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str. 6a, D-82319 Seewiesen, Germany.
| | - J Blas
- Department of Conservation Biology, Estación Biológica de Doñana CSIC, Avenida de Américo Vespucio s/n, E-41092 Sevilla, Spain
| | - W Goymann
- Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str. 6a, D-82319 Seewiesen, Germany
| |
Collapse
|
26
|
Villavicencio CP, Apfelbeck B, Goymann W. Parental care, loss of paternity and circulating levels of testosterone and corticosterone in a socially monogamous song bird. Front Zool 2014; 11:11. [PMID: 24517241 PMCID: PMC3932846 DOI: 10.1186/1742-9994-11-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/09/2014] [Indexed: 11/29/2022] Open
Abstract
Introduction In biparental birds testosterone levels of males are typically high during the mating phase and decrease during the parental phase. Testosterone implants may enhance mating behaviors, increase the likelihood of males to engage in extra-pair mating behavior and may reduce paternal care. Thus, sex steroids such as testosterone influence reproductive behaviors. Little is known, however, as to whether the more subtle differences in physiological concentrations of testosterone that occur between individuals are related to differences in paternal care, extra-pair behavior, and genetic paternity between those males. Here, we investigate these relationships in the male black redstart (Phoenicurus ochruros), a socially monogamous songbird with a low breeding synchrony. We used nestling provisioning as a proxy for parental care behavior and genetic paternity loss as a proxy for the efficiency of mate-guarding. Results There was no relationship between nestling provisioning and paternity loss of males. Baseline and gonadotropin releasing hormone (GnRH)-induced levels of testosterone, but not baseline corticosterone, were significantly higher during the mating than during the provisioning phase. Males fed more often when temperatures decreased and fed less when they sang more, but we found no correlation between parental behavior and baseline or GnRH-induced testosterone, and baseline corticosterone – both measured during either the mating or the parental phase. However, males that experienced loss of paternity had lower levels of testosterone during the provisioning phase than males that did not lose paternity. Further, males that lost paternity also expressed higher baseline levels of corticosterone. Conclusions Physiological differences in testosterone or baseline corticosterone were not related to differences in parental care, suggesting that the variation of testosterone within a physiological range may not relate to the degree of paternal care in this species. However, the profile of both hormones may indicate quality traits that influence the likelihood of the respective male to lose paternity.
Collapse
Affiliation(s)
- Camila P Villavicencio
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str, 6a, D-82319 Seewiesen, Germany.
| | | | | |
Collapse
|
27
|
Villavicencio CP, Apfelbeck B, Goymann W. Experimental induction of social instability during early breeding does not alter testosterone levels in male black redstarts, a socially monogamous songbird. Horm Behav 2013; 64:461-7. [PMID: 23981955 DOI: 10.1016/j.yhbeh.2013.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 08/01/2013] [Accepted: 08/13/2013] [Indexed: 01/25/2023]
Abstract
Testosterone plays an important role in territorial behavior of many male vertebrates and the Challenge Hypothesis has been suggested to explain differences in testosterone concentrations between males. For socially monogamous birds, the challenge hypothesis predicts that testosterone should increase during male-male interactions. To test this, simulated territorial intrusion (STI) experiments have been conducted, but only about a third of all bird species investigated so far show the expected increase in testosterone. Previous studies have shown that male black redstarts (Phoenicurus ochruros) do not increase testosterone during STIs or short-term male-male challenges. The aim of this study was to evaluate whether black redstarts modulate testosterone in an experimentally induced longer-term unstable social situation. We created social instability by removing males from their territories and compared the behavior and testosterone concentrations of replacement males and neighbors with those of control areas. Testosterone levels did not differ among replacement males, neighbors and control males. Injections with GnRH resulted in elevation of testosterone in all groups, suggesting that all males were capable of increasing testosterone. We found no difference in the behavioral response to STIs between control and replacement males. Furthermore, there was no difference in testosterone levels between replacement males that had expanded their territory and new-coming males. In combination with prior work these data suggest that testosterone is not modulated by male-male interactions in black redstarts and that testosterone plays only a minor role in territorial behavior. We suggest that territorial behavior in species that are territorial throughout most of their annual life-cycle may be decoupled from testosterone.
Collapse
Affiliation(s)
- Camila P Villavicencio
- Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str. 6a, D-82319 Seewiesen, Germany.
| | | | | |
Collapse
|
28
|
Vitousek MN, Romero LM. Stress responsiveness predicts individual variation in mate selectivity. Gen Comp Endocrinol 2013; 187:32-8. [PMID: 23524274 DOI: 10.1016/j.ygcen.2013.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 02/06/2013] [Accepted: 03/04/2013] [Indexed: 11/28/2022]
Abstract
Steroid hormones, including glucocorticoids, mediate a variety of behavioral and physiological processes. Circulating hormone concentrations vary substantially within populations, and although hormone titers predict reproductive success in several species, little is known about how individual variation in circulating hormone concentrations is linked with most reproductive behaviors in free-living organisms. Mate choice is an important and often costly component of reproduction that also varies substantially within populations. We examined whether energetically costly mate selection behavior in female Galápagos marine iguanas (Amblyrhynchus cristatus) was associated with individual variation in the concentrations of hormones previously shown to differ between reproductive and non-reproductive females during the breeding season (corticosterone and testosterone). Stress-induced corticosterone levels - which are suppressed in female marine iguanas during reproduction - were individually repeatable throughout the seven-week breeding period. Mate selectivity was strongly predicted by individual variation in stress-induced corticosterone: reproductive females that secreted less corticosterone in response to a standardized stressor assessed more displaying males. Neither baseline corticosterone nor testosterone predicted variation in mate selectivity. Scaled body mass was not significantly associated with mate selectivity, but females that began the breeding period in lower body condition showed a trend towards being less selective about potential mates. These results provide the first evidence that individual variation in the corticosterone stress response is associated with how selective females are in their choice of a mate, an important contributor to fitness in many species. Future research is needed to determine the functional basis of this association, and whether transient acute increases in circulating corticosterone directly mediate mate choice behaviors.
Collapse
Affiliation(s)
- Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
| | | |
Collapse
|
29
|
Kalbitzer U, Heistermann M. Long‐term storage effects in steroid metabolite extracts from baboon (
Papio
sp.) faeces – a comparison of three commonly applied storage methods. Methods Ecol Evol 2013. [DOI: 10.1111/2041-210x.12054] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Urs Kalbitzer
- Cognitive Ethology Laboratory German Primate Center (DPZ) Kellnerweg 4 37077 Göttingen Germany
| | | |
Collapse
|
30
|
Apfelbeck B, Mortega K, Kiefer S, Kipper S, Vellema M, Villavicencio CP, Gahr M, Goymann W. Associated and disassociated patterns in hormones, song, behavior and brain receptor expression between life-cycle stages in male black redstarts, Phoenicurus ochruros. Gen Comp Endocrinol 2013; 184:93-102. [PMID: 23337030 DOI: 10.1016/j.ygcen.2012.11.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/24/2012] [Accepted: 11/22/2012] [Indexed: 12/22/2022]
Abstract
Testosterone has been suggested to be involved in the regulation of male territorial behavior. For example, seasonal peaks in testosterone typically coincide with periods of intense competition between males for territories and mating partners. However, some species also express territorial behavior outside a breeding context when testosterone levels are low and, thus, the degree to which testosterone facilitates territorial behavior in these species is not well understood. We studied territorial behavior and its neuroendocrine correlates in male black redstarts. Black redstarts defend territories in spring during the breeding period, but also in the fall outside a reproductive context when testosterone levels are low. In the present study we assessed if song output and structure remain stable across life-cycle stages. Furthermore, we assessed if brain anatomy may give insight into the role of testosterone in the regulation of territorial behavior in black redstarts. We found that males sang spontaneously at a high rate during the nonbreeding period when testosterone levels were low; however the trill-like components of spontaneously produced song contained less repetitive elements during nonbreeding than during breeding. This higher number of repetitive elements in trills did not, however, correlate with a larger song control nucleus HVC during breeding. However, males expressed more aromatase mRNA in the preoptic area - a brain nucleus important for sexual and aggressive behavior - during breeding than during nonbreeding. In combination with our previous studies on black redstarts our results suggest that territorial behavior in this species only partly depends on sex steroids: spontaneous song output, seasonal variation in trills and non-vocal territorial behavior in response to a simulated territorial intruder seem to be independent of sex steroids. However, context-dependent song during breeding may be facilitated by testosterone - potentially by conversion of testosterone to estradiol in the preoptic area.
Collapse
Affiliation(s)
- Beate Apfelbeck
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Seewiesen, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Apfelbeck B, Stegherr J, Goymann W. Simulating winning in the wild--the behavioral and hormonal response of black redstarts to single and repeated territorial challenges of high and low intensity. Horm Behav 2011; 60:565-71. [PMID: 21872602 DOI: 10.1016/j.yhbeh.2011.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 08/11/2011] [Accepted: 08/12/2011] [Indexed: 10/17/2022]
Abstract
In many vertebrates testosterone increases during aggressive interactions and the surges in this hormone may be responsible for the winner effect. So far studies on this relationship have been done in captivity only, because simulating a winning situation for a territory owner in the field is difficult. However, an increasing number of studies show that territorial aggression is not necessarily accompanied by elevated testosterone after a single simulated territorial intrusion (STI) and therefore it has been proposed that STIs may even create a losing experience. We examined whether free-living male black redstarts (Phoenicurus ochruros) show changes in androgens, corticosterone and behavior following repeated STIs of high or low intensity and in contrast to being challenged only once. Repeated intrusions had no influence on androgen and corticosterone levels regardless of intrusion intensity. In contrast, the behavioral response changed over days depending on the intensity of the intrusion. Only birds challenged with high-level intruders approached the decoy significantly faster during the third intrusion than during the first one, stayed closer to the decoy, and sang more songs than males challenged with low-level intruders. Thus, although black redstarts reacted differently to STIs varying in frequency and intensity, these behavioral differences were not reflected in androgen or corticosterone levels. Our data show that it is unlikely that STIs induce a losing experience. Furthermore, they indicate that a hormonal effect of winning an encounter may not be universal in vertebrates and may depend on the ecological or life-history context.
Collapse
Affiliation(s)
- Beate Apfelbeck
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str. Haus 6a, D-82319 Seewiesen, Germany.
| | | | | |
Collapse
|
32
|
Grace JK, Dean K, Ottinger MA, Anderson DJ. Hormonal effects of maltreatment in Nazca booby nestlings: implications for the "cycle of violence". Horm Behav 2011; 60:78-85. [PMID: 21439288 DOI: 10.1016/j.yhbeh.2011.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 03/14/2011] [Accepted: 03/17/2011] [Indexed: 11/25/2022]
Abstract
Non-breeding Nazca booby adults exhibit an unusual and intense social attraction to non-familial conspecific nestlings. Non-parental Adult Visitors (NAVs) seek out and approach unguarded nestlings during daylight hours and display parental, aggressive, and/or sexual behavior. In a striking parallel to the "cycle of violence" of human biology, degree of victimization as a nestling is strongly correlated with frequency of future maltreatment behavior exhibited as an adult. Here, we investigate candidates for permanent organization of this behavior, including immediate and long-term changes in growth and circulating corticosterone and testosterone due to victimization, by protecting some nestlings with portable exclosures that prevented NAV visits and comparing them to controls. During maltreatment episodes, nestlings experience an approximately five-fold increase in corticosterone concentration, and corticosterone remains elevated approximately 2.8-fold until at least the following morning. Our results are consistent with the possibility that repeated activation of the hypothalamic-pituitary-adrenal axis permanently organizes future adult maltreatment behavior. No effect on growth, acute or chronic changes in testosterone, or chronic corticosterone elevation was detected or appeared to be components of an organizational effect. This unusual behavior presents an opportunity to investigate neural, endocrine, and behavioral organization resulting from early social trauma that may be conserved across vertebrate classes.
Collapse
Affiliation(s)
- Jacquelyn K Grace
- Dept. of Biology, Wake Forest University, Winston-Salem, NC 27106, USA.
| | | | | | | |
Collapse
|
33
|
Apfelbeck B, Goymann W. Ignoring the challenge? Male black redstarts (Phoenicurus ochruros) do not increase testosterone levels during territorial conflicts but they do so in response to gonadotropin-releasing hormone. Proc Biol Sci 2011; 278:3233-42. [PMID: 21325321 DOI: 10.1098/rspb.2011.0098] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Competition elevates plasma testosterone in a wide variety of vertebrates, including humans. The 'challenge hypothesis' proposes that seasonal peaks in testosterone during breeding are caused by social challenges from other males. However, during experimentally induced male-male conflicts, testosterone increases only in a minority of songbird species tested so far. Why is this so? Comparative evidence suggests that species with a short breeding season may not elevate testosterone levels during territory defence. These species may even be limited in their physiological capability to increase testosterone levels, which can be tested by injecting birds with gonadotropin-releasing hormone (GnRH). We studied two populations of black redstarts that differ in breeding altitude, morphology and the length of their breeding season. Unexpectedly, males of neither population increased testosterone in response to a simulated territorial intrusion, but injections with GnRH resulted in a major elevation of testosterone. Thus, black redstarts would have been capable of mounting a testosterone response during the male-male challenge. Our data show, for the first time, that the absence of an androgen response to male-male challenges is not owing to physiological limitations to increase testosterone. Furthermore, in contrast to comparative evidence between species, populations of black redstarts with a long breeding season do not show the expected elevation in testosterone during male-male challenges.
Collapse
Affiliation(s)
- Beate Apfelbeck
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Straße 6a, 82319 Seewiesen, Germany.
| | | |
Collapse
|
34
|
Boyle WA, Norris DR, Guglielmo CG. Storms drive altitudinal migration in a tropical bird. Proc Biol Sci 2010; 277:2511-9. [PMID: 20375047 DOI: 10.1098/rspb.2010.0344] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Although migration is a widespread and taxonomically diverse behaviour, the ecological factors shaping migratory behaviour are poorly understood. Like other montane taxa, many birds migrate along elevational gradients in the tropics. Forty years ago, Alexander Skutch postulated that severe storms could drive birds to migrate downhill. Here, we articulate a novel mechanism that could link storms to mortality risks via reductions in foraging time and provide, to our knowledge, the first tests of this hypothesis in the White-ruffed Manakin (Corapipo altera), a small partially migratory frugivore breeding on the Atlantic slope of Costa Rica. As predicted, variation in rainfall was associated with plasma corticosterone levels, fat stores, plasma metabolites and haematocrit. By collecting data at high and low elevation sites simultaneously, we also found that high-elevation residents were more adversely affected by storms than low elevation migrants. These results, together with striking temporal capture patterns of altitudinal migrants relative to storms, provide, to our knowledge, the first evidence that weather-related risks incurred by species requiring high food intake rates can explain altitudinal migrations of tropical animals. These findings resolve conflicting evidence for and against food limitation being important in the evolution of this behaviour, and highlight how endogenous and exogenous processes influence life-history trade-offs made by individuals in the wild. Because seasonal storms are a defining characteristic of most tropical ecosystems and rainfall patterns will probably change in ensuing decades, these results have important implications for understanding the ecology, evolution and conservation of tropical animals.
Collapse
Affiliation(s)
- W Alice Boyle
- Department of Biology, University of Western Ontario, London, Ontario, Canada, N6A 5B7.
| | | | | |
Collapse
|
35
|
Vitousek MN, Mitchell MA, Romero LM, Awerman J, Wikelski M. To breed or not to breed: physiological correlates of reproductive status in a facultatively biennial iguanid. Horm Behav 2010; 57:140-6. [PMID: 19818354 DOI: 10.1016/j.yhbeh.2009.09.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 09/29/2009] [Accepted: 09/30/2009] [Indexed: 11/29/2022]
Abstract
It is unusual for seasonal breeders to frequently skip opportunities for reproduction. We investigated the relationship between physiological state and reproductive decision-making in Galápagos marine iguanas (Amblyrhynchus cristatus), a species in which females typically reproduce biennially, although the proportion of breeding individuals varies significantly across years. Nearly all adult-sized females initiated follicular development prior to the lekking period, but 38% of females resorbed all developing follicles 5-15 days before the start of copulations. Receptive and non-receptive females differed in reproductive hormones during the mate choice period. Testosterone peaked in receptive females immediately prior to copulation, indicating that testosterone or its derivative estradiol likely mediates female receptivity in Galápagos marine iguanas. Non-receptive females showed significant peaks in both testosterone and progesterone during follicular atresia, suggesting that these hormones may be involved in inhibiting vitellogenesis. Two to three weeks prior to the period of reproductive decision-making (and the onset of follicular atresia in non-receptive females) receptive females were in higher body condition, were developing larger follicles, and had lower levels of both baseline and stress-induced corticosterone. Reproduction is extremely costly in this long-lived species, and increases the likelihood of mortality in the year following breeding; females could therefore gain significant benefits from being attuned to indicators of reproductive success. We suggest that corticosterone may modulate reproductive decisions by altering individual sensitivity to both internal and external cues of the likelihood of successful reproduction.
Collapse
Affiliation(s)
- Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
| | | | | | | | | |
Collapse
|
36
|
Investment in mate choice depends on resource availability in female Galápagos marine iguanas (Amblyrhynchus cristatus). Behav Ecol Sociobiol 2009. [DOI: 10.1007/s00265-009-0825-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
37
|
Silverin B, Gwinner E, Van't Hof TJ, Schwabl I, Fusani L, Hau M, Helm B. Persistent diel melatonin rhythmicity during the Arctic summer in free-living willow warblers. Horm Behav 2009; 56:163-8. [PMID: 19374903 DOI: 10.1016/j.yhbeh.2009.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 04/03/2009] [Accepted: 04/03/2009] [Indexed: 10/20/2022]
Abstract
Arctic environments are challenging for circadian systems. Around the solstices, the most important zeitgeber, the change between night and day, is reduced to minor fluctuations in light intensities. However, many species including songbirds nonetheless show clear diel activity patterns. Here we examine the possible physiological basis underlying diel rhythmicity under continuous Arctic summer light. Rhythmic secretion of the hormone melatonin constitutes an important part of the songbird circadian system and its experimental suppression, e.g., by constant light, usually leads to behavioral arrhythmia. We therefore studied melatonin patterns in a free-living migratory songbird, the willow warbler (Phylloscopus trochilus), that maintains diel activity during the Arctic summer. We compared melatonin profiles during late spring and summer solstice in two Swedish populations from the south (58 degrees N) and near the Arctic circle (66 degrees N). We found the northern Swedish population maintained clear diel changes in melatonin secretion during the summer solstice, although peak concentrations were lower than in southern Sweden. Melatonin levels were highest before midnight and in good accordance with periods of reduced activity. The maintenance of diel melatonin rhythmicity under conditions of continuous light may be one of the physiological mechanisms that enables continued functioning of the circadian system.
Collapse
Affiliation(s)
- Bengt Silverin
- Department of Zoology, University of Gothenburg, Gothenburg, Sweden
| | | | | | | | | | | | | |
Collapse
|
38
|
Vitousek MN, Rubenstein DR, Nelson KN, Wikelski M. Are hotshots always hot? A longitudinal study of hormones, behavior, and reproductive success in male marine iguanas. Gen Comp Endocrinol 2008; 157:227-32. [PMID: 18571171 DOI: 10.1016/j.ygcen.2008.04.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Accepted: 04/28/2008] [Indexed: 11/27/2022]
Abstract
Polygynous lek-mating systems are characterized by high reproductive skew, with a small number of males gaining a disproportionate share of copulations. In lekking species, where female choice drives male mating success and patterns of reproductive skew, female preferences for 'good genes' should lead to preferred males having high reproductive success in all years. Here we investigate whether these 'hotshot' males have steroid hormone patterns that are consistent over time (between two mating seasons), and whether hormone levels consistently predict display behavior. We test these questions in the Galápagos marine iguana (Amblyrhynchus cristatus), a lekking vertebrate with high male reproductive skew. We found that male mating success and testosterone levels were not consistent across years. The most successful males showed an inverse relationship in copulation success between years. Similarly, territorial males that had high testosterone in one year had low levels in the next. Across years, testosterone was strongly associated with head-bob display, suggesting that this steroid plays a key role in mate attraction. These results suggest that female marine iguanas are not choosing the same 'hotshot' males in every year, but instead base their reproductive decisions on male behavioral traits that are hormonally mediated and variable across years. By using testosterone to regulate their costly display behaviors male marine iguanas appear to have a mechanism that allows them to adjust their reproductive effort depending on extrinsic and/or intrinsic factors.
Collapse
Affiliation(s)
- Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | | | | | | |
Collapse
|
39
|
Goymann W, Trappschuh M, Fusani L. A Gentler Method to Raise Melatonin Levels in Birds. J Biol Rhythms 2008; 23:274-7. [DOI: 10.1177/0748730408316349] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Wolfgang Goymann
- Max-Planck-Institut für Ornithologie, Abteilung für Verhaltensneurobiologie, Seewiesen, Germany,
| | - Monika Trappschuh
- Max-Planck-Institut für Ornithologie, Abteilung für Verhaltensneurobiologie, Seewiesen, Germany
| | - Leonida Fusani
- Universitá di Ferrara, Dipartimento di Biologia e Evoluzione, Ferrara, Italy
| |
Collapse
|
40
|
Bibliography. Current world literature. Adrenal cortex. Curr Opin Endocrinol Diabetes Obes 2008; 15:284-299. [PMID: 18438178 DOI: 10.1097/med.0b013e3283040e80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|