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Alward BA, Balthazart J, Ball GF. Androgen signaling in LMAN regulates song stereotypy in male canaries. Horm Behav 2024; 165:105611. [PMID: 39089160 DOI: 10.1016/j.yhbeh.2024.105611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 06/15/2024] [Accepted: 07/22/2024] [Indexed: 08/03/2024]
Abstract
During breeding when testosterone concentrations are high, male songbirds that are open-ended vocal learners like canaries (Serinus canaria) tend to produce a stable, stereotyped song that facilitates mate attraction or territory defense. Outside breeding contexts, song becomes more variable. The neuroendocrine mechanisms controlling this vocal variability across seasons are not entirely clear. We tested whether androgen signaling within the lateral magnocellular nucleus of the anterior nidopallium (LMAN), a cortical-like brain region of the vocal control system known as a vocal variability generator, plays a role in seasonal vocal variability. We first characterized song in birds housed alone on a short day (SD) photoperiod, which simulates non-breeding conditions. Then, cannulae filled with the androgen receptor (AR) blocker flutamide or left empty as control were implanted bilaterally in LMAN. Birds were then transferred to long days (LD) to simulate the breeding season and song was analyzed again. Blocking AR in LMAN increased acoustic variability of song and the acoustic variability of syllables. However, blocking AR in LMAN did not impact the variability of syllable usage nor their sequencing in LD birds, song features that are controlled by androgen signaling in a somatosensory brain region of the vocal control system called HVC. These findings highlight the multifactorial, non-redundant actions of steroid hormones in controlling complex social behaviors such as birdsong. They also support the hypothesis that LMAN is a key brain area for the effects of testosterone on song plasticity both seasonally in adults and during the song crystallization process at sexual maturity.
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Affiliation(s)
- Beau A Alward
- Department of Psychology, T.I.M.E.S, University of Houston, Houston, TX 77204, USA; Department of Biology and Biochemistry, University of Houston, Houston, TX 77004, USA; Department of Psychology, Neural and Cognitive Science Program, University of Maryland, College Park, MD 20742, USA
| | | | - Gregory F Ball
- Department of Psychology, Neural and Cognitive Science Program, University of Maryland, College Park, MD 20742, USA
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2
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Jackson LR, Alward BA. Sexually dimorphic control of aggression by androgen signaling in a cichlid. Mol Cell Endocrinol 2024; 592:112319. [PMID: 38925266 DOI: 10.1016/j.mce.2024.112319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 06/28/2024]
Abstract
Innate social behaviors like aggression are modulated by sex steroid hormones such as androgens and estrogens. However, we know little about how the same hormone regulates similar behaviors in both sexes. We investigated the role of androgenic signaling in the regulation of aggression in Astatotilapia burtoni, a social fish in which males and females perform similar aggressive behaviors. We used androgen receptor (AR) α knockout (KO) animals for this study since this gene was recently shown to be required for male-typical aggression and mating. Surprisingly, ARα KO females did not show deficits in aggression. We also determined that females lacking the other AR, ARβ, showed normal levels of aggression. Blocking both ARs pharmacologically confirmed that neither AR is necessary for aggression in females. However, ARα KO males showed clear deficits in attacks. Thus, in A. burtoni there appears to be a sexual dimorphism in the role of ARα in the control of aggression.
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Affiliation(s)
| | - Beau A Alward
- University of Houston, Department of Psychology, USA; University of Houston, Department of Biology and Biochemistry, USA; University of California, Los Angeles, Department of Integrative Biology and Physiology, USA.
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3
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Lin JC, Daigle CL, Tang PC, Wang CK. Influence of sex hormones on the aggressive behavior during peck order establishment and stabilization in meat and egg type chickens. Poult Sci 2024; 103:103669. [PMID: 38603931 PMCID: PMC11017360 DOI: 10.1016/j.psj.2024.103669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/10/2024] [Accepted: 03/12/2024] [Indexed: 04/13/2024] Open
Abstract
In the poultry industry, broiler and layer strains are genetically selected for different purposes (e.g., high meat-yield and high egg-production). Genetic selection for productivity can have unintended consequences on the behavioral repertoire of the birds, including aggression. Alongside the increasing societal concern regarding the welfare of animal in agriculture, the number of countries that are advocating the prohibition of using battery cages for laying hens has resulted in the transition and adoption of cage-free or free-range systems. Thus, both broiler and layer chickens are housed in large flocks rather than housed individually in cages. Housing birds in groups increases the opportunity for birds to engage in social behaviors, including aggression, that are used to establish social status. Aggressive interactions are associated with the risk of injury and the potential for a subordinate animal to have unmet needs (e.g., access to feed). The aim of this study was to characterize the relationships among aggressive behavior, neurobiology, and hormones during peck order establishment and social hierarchy stabilization of 2 divergently selected strains (meat- and egg-type chicken). Meat-type strains performed more male on male (P < 0.001), male on female (P < 0.0001), and female on female (P < 0.0001) non-reciprocal aggression behavior (NRA) than egg-type strains. Greater serum testosterone and estradiol concentrations in the weeks after the peck order establishment were observed in meat-type birds compared those in egg-type birds for both males and females (all P < 0.05). Greater (P < 0.05) cellular densities of androgen receptors, but not estrogen receptors, were observed in the hypothalamus of meat-type birds compared to egg-type birds. These findings suggest that greater sex hormone concentrations in the meat-type birds may be a consequence of genetic selection for rapid growth resulting in more sex hormones-induced aggressive behavior.
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Affiliation(s)
- Jou-Ching Lin
- Department of Animal Science, National Chung Hsing University, Taichung 40227, Taiwan
| | - Courtney Lynd Daigle
- Department of Animal Science, Texas A&M University, Kleberg Center, College Station, TX 77843, USA
| | - Pin-Chi Tang
- Department of Animal Science, National Chung Hsing University, Taichung 40227, Taiwan; The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Chien-Kai Wang
- Department of Animal Science, National Chung Hsing University, Taichung 40227, Taiwan; The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan.
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4
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Jackson LR, Alward B. Sexually dimorphic control of aggression by androgen signaling in a cichlid. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.587979. [PMID: 38617319 PMCID: PMC11014533 DOI: 10.1101/2024.04.03.587979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Innate social behaviors like aggression are modulated by sex steroid hormones such as androgens and estrogens. However, we know little about how the same hormone regulates similar behaviors in both sexes. We investigated the role of androgenic signaling in the regulation of aggression in Astatotilapia burtoni, a social fish in which males and females perform similar aggressive behaviors. We used ARa knockout (KO) animals for this study, which was recently shown to be required for male-typical aggression and mating. Surprisingly, ARα KO females did not show deficits in aggression. We also determined that females lacking the other AR, ARβ, showed normal levels of aggression. Blocking both ARs pharmacologically confirmed that neither AR is necessary for aggression in females. However, ARα KO males showed clear deficits in attacks. Thus, in A. burtoni there appears to be a sexual dimorphism in the role of ARα in the control of aggression.
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Affiliation(s)
| | - Beau Alward
- University of Houston, Department of Psychology
- University of Houston, Department of Biology and Biochemistry
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5
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Valiño G, Dunlap K, Quintana L. Androgen receptors rapidly modulate non-breeding aggression in male and female weakly electric fish (Gymnotus omarorum). Horm Behav 2024; 159:105475. [PMID: 38154435 DOI: 10.1016/j.yhbeh.2023.105475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 12/30/2023]
Abstract
The South American weakly electric fish, Gymnotus omarorum, displays territorial aggression year-round in both sexes. To examine the role of rapid androgen modulation in non-breeding aggression, we administered acetate cyproterone (CPA), a potent inhibitor of androgen receptors, to both male and females, just before staged agonistic interactions. Wild-caught fish were injected with CPA and, 30 min later, paired in intrasexual dyads. We then recorded the agonistic behavior which encompasses both locomotor displays and emission of social electric signals. We found that CPA had no discernible impact on the levels of aggression or the motivation to engage in aggressive behavior for either sex. However, CPA specifically decreased the expression of social electric signals in both males and female dyads. The effect was status-dependent as it only affected subordinate electrocommunication behavior, the emission of brief interruptions in their electric signaling ("offs"). This study is the first demonstration of a direct and rapid androgen effect mediated via androgen receptors on non-breeding aggression. Elucidating the mechanisms involved in non-breeding aggression in this teleost model allows us to better understand potentially conserved or convergent neuroendocrine mechanisms underlying aggression in vertebrates.
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Affiliation(s)
- Guillermo Valiño
- Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Montevideo, Uruguay
| | - Kent Dunlap
- Department of Biology, Trinity College, Hartford, CT, United States
| | - Laura Quintana
- Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Montevideo, Uruguay.
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6
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Zubizarreta L, Jalabert C, Silva AC, Soma KK, Quintana L. Brain and circulating steroids in an electric fish: Relevance for non-breeding aggression. PLoS One 2023; 18:e0289461. [PMID: 37816021 PMCID: PMC10564164 DOI: 10.1371/journal.pone.0289461] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/23/2023] [Indexed: 10/12/2023] Open
Abstract
Steroids play a crucial role in modulating brain and behavior. While traditionally it is thought that the brain is a target of sex steroids produced in endocrine glands (e.g. gonads), the brain itself produces steroids, known as neurosteroids. Neurosteroids can be produced in regions involved in the regulation of social behaviors and may act locally to regulate social behaviors, such as reproduction and aggression. Our model species, the weakly electric fish Gymnotus omarorum, displays non-breeding aggression in both sexes. This is a valuable natural behavior to understand neuroendocrine mechanisms that differ from those underlying breeding aggression. In the non-breeding season, circulating sex steroid levels are low, which facilitates the study of neurosteroids. Here, for the first time in a teleost fish, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify a panel of 8 steroids in both plasma and brain to characterize steroid profiles in wild non-breeding adult males and females. We show that: 1) systemic steroid levels in the non-breeding season are similar in both sexes, although only males have detectable circulating 11-ketotestosterone, 2) brain steroid levels are sexually dimorphic, as females display higher levels of androstenedione, testosterone and estrone, and only males had detectable 11-ketotestosterone, 3) systemic androgens such as androstenedione and testosterone in the non-breeding season are potential precursors for neuroestrogen synthesis, and 4) estrogens, which play a key role in non-breeding aggression, are detectable in the brain (but not the plasma) in both sexes. These data are consistent with previous studies of G. omarorum that show non-breeding aggression is dependent on estrogen signaling, as has also been shown in bird and mammal models. Overall, our results provide a foundation for understanding the role of neurosteroids, the interplay between central and peripheral steroids and potential sex differences in the regulation of social behaviors.
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Affiliation(s)
- Lucia Zubizarreta
- Laboratorio de Neurofisiología Celular y Sináptica, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Ministerio de Educación y Cultura, Montevideo, Uruguay
| | - Cecilia Jalabert
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ana C. Silva
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Kiran K. Soma
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Psychology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Laura Quintana
- Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Ministerio de Educación y Cultura, Montevideo, Uruguay
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Boersma J, Enbody ED, Ketaloya S, Watts HE, Karubian J, Schwabl H. Does capacity to produce androgens underlie variation in female ornamentation and territoriality in White-shouldered Fairywren (Malurus alboscapulatus)? Horm Behav 2023; 154:105393. [PMID: 37331309 DOI: 10.1016/j.yhbeh.2023.105393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/20/2023]
Abstract
Historic bias toward study of sex hormones and sexual ornamentation in males currently constrains our perspective of hormone-behavior-phenotype relationships. Resolving how ornamented female phenotypes evolve is particularly important for understanding the diversity of social signals across taxa. Studies of both males and females in taxa with variable female phenotypes are needed to establish whether sexes share mechanisms underlying expression of signaling phenotypes and behavior. White-shouldered Fairywren (Malurus alboscapulatus) subspecies vary in female ornamentation, baseline circulating androgens, and response to territorial intrusion. The moretoni ornamented female subspecies is characterized by higher female, but lower male baseline androgens, and a stronger pair territorial response relative to pairs from the lorentzi unornamented female subspecies. Here we address whether subspecific differences in female ornamentation, baseline androgens, and pair territoriality are associated with ability to elevate androgens following gonadotropin releasing hormone (GnRH) challenge and in response to simulated territorial intrusion. We find that subspecies do not differ in their capacity to produce androgens in either sex following GnRH or simulated territorial intrusion (STI) challenges. STI-induced androgens were predictive of degree of response to territorial intrusions in females only, but the direction of the effect was mixed. GnRH-induced androgens did not correlate with response to simulated intruders, nor did females sampled during intrusion elevate androgens relative to flushed controls, suggesting that increased androgens are not necessary for the expression of territorial defense behaviors. Collectively, our results suggest that capacity to produce androgens does not underlie subspecific patterns of female ornamentation, territoriality, and baseline plasma androgens.
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Affiliation(s)
- Jordan Boersma
- School of Biological Sciences, Washington State University, Pullman, WA, USA; Cornell Lab of Ornithology, Ithaca, NY, USA; Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA.
| | - Erik D Enbody
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA, USA; Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| | - Serena Ketaloya
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA; Porotona Village, Milne Bay Province, Papua New Guinea
| | - Heather E Watts
- School of Biological Sciences, Washington State University, Pullman, WA, USA; Center for Reproductive Biology, Washington State University, Pullman, WA, USA
| | - Jordan Karubian
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| | - Hubert Schwabl
- School of Biological Sciences, Washington State University, Pullman, WA, USA; Center for Reproductive Biology, Washington State University, Pullman, WA, USA
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8
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Boersma J, McQueen A, Peters A, Welklin JF, Khalil S, Quispe R, Goymann W, Schwabl H. Unexpected long-term retention of subcutaneous beeswax implants and additional notes on dose and composition from four testosterone implant studies. Gen Comp Endocrinol 2023; 330:114124. [PMID: 36243058 DOI: 10.1016/j.ygcen.2022.114124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/20/2022] [Accepted: 08/31/2022] [Indexed: 11/17/2022]
Abstract
Experimental manipulations of testosterone have advanced our understanding of the hormonal control of traits across vertebrates. Implants are commonly used to supplement testosterone and other hormones to organisms, as they can be readily scaled to produce desired hormone levels in circulation. Concerns about pharmacological (i.e. unnatural) doses of traditional silastic implants led to innovation in implant methods, with time-release pellets and beeswax implants proposed as solutions. A study comparing silastic, time-release pellets, and beeswax implants found the latter to be most effective in delivering a physiologically relevant dose. One proposed advantage to subcutaneous beeswax implants is that they are expected to degrade within the body, thus removing the obligation to recapture implanted individuals in the field. However, few studies have reported on dosage and no published literature has examined the assumption that beeswax implants readily degrade as expected. Here we present time-release androgen data in relation to implants containing varying levels of testosterone from four separate implant studies. In addition, we report long-term persistence of subcutaneous implants, including two cases of implants being retained for > 2 years. Finally, we offer recommendations on the composition and implementation of beeswax implants to aid the pursuit of minimally invasive and physiologically relevant manipulations of circulating hormones.
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Affiliation(s)
- Jordan Boersma
- School of Biological Sciences, Washington State University, Pullman, WA, USA; Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA.
| | - Alexandra McQueen
- School of Biological Sciences, Monash University, Clayton, VIC, Australia; Centre for Integrative Ecology, Deakin University, Burwood, VIC, Australia
| | - Anne Peters
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | | | - Sarah Khalil
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA
| | - René Quispe
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Seewiesen, Germany; Departmento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, CL, USA
| | - Wolfgang Goymann
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Seewiesen, Germany
| | - Hubert Schwabl
- School of Biological Sciences, Washington State University, Pullman, WA, USA; Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Seewiesen, Germany
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9
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Drea CM, Davies CS. Meerkat manners: Endocrine mediation of female dominance and reproductive control in a cooperative breeder. Horm Behav 2022; 145:105245. [PMID: 35988450 DOI: 10.1016/j.yhbeh.2022.105245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/18/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022]
Abstract
This article is part of a Special Issue (Hormones and Hierarchies). To gain more balanced understanding of sexual selection and mammalian sexual differentiation processes, this review addresses behavioral sex differences and hormonal mediators of intrasexual competition in the meerkat (Suricata suricatta) - a cooperative breeder unusual among vertebrates in its female aggression, degree of reproductive skew, and phenotypic divergence. Focused on the evolution, function, mechanism, and development of female dominance, the male remains a key reference point throughout. Integrated review of endocrine function does not support routine physiological suppression in subordinates of either sex, but instead a ramp up of weight, reproduction, aggression, and sex steroids, particularly androgens, in dominant females. Important and timely questions about female competition are thus addressed by shifting emphasis from mediators of reproductive suppression to mediators of reproductive control, and from organizational and activational roles of androgens in males to their roles in females. Unusually, we ask not only how inequity is maintained, but how dominance is acquired within a lifetime and across generations. Antiandrogens administered in the field to males and pregnant dominant females confirm the importance of androgen-mediated food competition. Moreover, effects of maternal endocrine milieu on offspring development reveal a heritable, androgenic route to female aggression, likely promoting reproductive priority along dominant matrilines. Integrating endocrine measures with long-term behavioral, ecological, morphological, and life-history data on normative and experimental individuals, across life stages and generations, provides better appreciation of the role of naturally circulating androgens in regulating the female phenotype, and sheds new light on the evolution of female dominance, reproductive inequity, and cooperative breeding.
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Affiliation(s)
- Christine M Drea
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708-0383, USA; Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa.
| | - Charli S Davies
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708-0383, USA; Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa
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10
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George EM, Rosvall KA. Bidirectional relationships between testosterone and aggression: a critical analysis of four predictions. Integr Comp Biol 2022; 62:icac100. [PMID: 35759399 PMCID: PMC9494517 DOI: 10.1093/icb/icac100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/05/2022] [Accepted: 06/09/2022] [Indexed: 12/12/2022] Open
Abstract
Experimentally elevated testosterone (T) often leads to enhanced aggression, with examples across many different species, including both males and females. Indeed, the relationship between T and aggression is among the most well-studied and fruitful areas of research at the intersection of behavioral ecology and endocrinology. This relationship is also hypothesized to be bidirectional (i.e., T influences aggression, and aggression influences T), leading to four key predictions: (1) Individuals with higher T levels are more aggressive than individuals with lower T. (2) Seasonal changes in aggression mirror seasonal changes in T secretion. (3) Aggressive territorial interactions stimulate increased T secretion. (4) Temporary elevations in T temporarily increase aggressiveness. These predictions cover a range of timescales, from a single snapshot in time, to rapid fluctuations, and to changes over seasonal timescales. Adding further complexity, most predictions can also be addressed by comparing among individuals or with repeated sampling within-individuals. In our review, we explore how the spectrum of results across predictions shapes our understanding of the relationship between T and aggression. In all cases, we can find examples of results that do not support the initial predictions. In particular, we find that predictions 1-3 have been tested frequently, especially using an among-individual approach. We find qualitative support for all three predictions, though there are also many studies that do not support predictions 1 and 3 in particular. Prediction 4, on the other hand, is something that we identify as a core underlying assumption of past work on the topic, but one that has rarely been directly tested. We propose that when relationships between T and aggression are individual-specific or condition-dependent, then positive correlations between the two variables may be obscured or reversed. In essence, even though T can influence aggression, many assumed or predicted relationships between the two variables may not manifest. Moving forward, we urge greater attention to understanding how and why it is that these bidirectional relationships between T and aggression may vary among timescales and among individuals. In doing so, we will move towards a deeper understanding on the role of hormones in behavioral adaptation.
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Affiliation(s)
- Elizabeth M George
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
- Center for the Integrated Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
| | - Kimberly A Rosvall
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
- Center for the Integrated Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
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11
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Allen CRB, Croft DP, Brent LJN. Reduced older male presence linked to increased rates of aggression to non-conspecific targets in male elephants. Proc Biol Sci 2021; 288:20211374. [PMID: 34933598 PMCID: PMC8692974 DOI: 10.1098/rspb.2021.1374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Males in many large mammal species spend a considerable portion of their lives in all-male groups segregated from females. In long-lived species, these all-male groups may contain individuals of vastly different ages, providing the possibility that behaviours such as aggression vary with the age demographic of the social environment, as well as an individual's own age. Here, we explore social factors affecting aggression and fear behaviours in non-musth male African elephants (Loxodonta africana) aggregating in an all-male area. Adolescent males had greater probabilities of directing aggressive and fearful behaviours to non-elephant targets when alone compared to when with other males. All males, regardless of age, were less aggressive towards non-elephant targets (e.g. vehicles and non-elephant animals) when larger numbers of males from the oldest age cohort were present. The presence of older males did not influence the probability that other males were aggressive to conspecifics or expressed fearful behaviours towards non-elephant targets. Older bulls may police aggression directed towards non-elephant targets or may lower elephants' perception of their current threat level. Our results suggest male elephants may pose an enhanced threat to humans and livestock when adolescents are socially isolated, and when fewer older bulls are nearby.
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Affiliation(s)
- Connie R. B. Allen
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK,Elephants for Africa, 5 Balfour Road, London N5 2HB, UK,School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Darren P. Croft
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK
| | - Lauren J. N. Brent
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK
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12
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Carver JJ, Carrell SC, Chilton MW, Brown JN, Yong L, Zhu Y, Issa FA. Nuclear androgen and progestin receptors inversely affect aggression and social dominance in male zebrafish (Danio rerio). Horm Behav 2021; 134:105012. [PMID: 34153924 PMCID: PMC8403641 DOI: 10.1016/j.yhbeh.2021.105012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/03/2021] [Accepted: 05/26/2021] [Indexed: 11/26/2022]
Abstract
Aggression is a fundamental behavior displayed universally among animal species, but hyper- or hypo-aggressiveness can be maladaptive with negative consequences for individuals and group members. While the social and ecological significance of aggression is well understood, the specific neurobiological and hormonal mechanisms responsible for mediating aggression have not been fully elucidated. Previous studies have shown a relationship between aggressive acts and circulating gonadal steroids, but whether classical nuclear steroid receptors regulate aggression in animals is still uncertain. We examined whether the nuclear androgen receptor (Ar) and nuclear progestin receptor (Pgr) were necessary for aggressive behaviors and maintenance of a dominance relationship in male zebrafish (Danio rerio). Dyadic social interactions of Ar knockout (ArKO), Pgr knockout (PgrKO) and wildtype (WT) controls were observed for two weeks (2-weeks). ArKO zebrafish were significantly less aggressive and had a less defined dominance relationship, whereas PgrKO dominant zebrafish were significantly and persistently more aggressive with a robust dominance relationship. Our results demonstrate the importance of nuclear steroid hormone receptors in regulating aggression of adult male zebrafish and provide new models for understanding of the mechanisms of aggression.
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Affiliation(s)
- Jonathan J Carver
- Department of Biology, East Carolina University, Greenville, NC 27285, USA
| | - Skyler C Carrell
- Department of Biology, East Carolina University, Greenville, NC 27285, USA
| | - Matthew W Chilton
- Department of Biology, East Carolina University, Greenville, NC 27285, USA
| | - Julia N Brown
- Department of Biology, East Carolina University, Greenville, NC 27285, USA
| | - Lengxob Yong
- Department of Biology, East Carolina University, Greenville, NC 27285, USA
| | - Yong Zhu
- Department of Biology, East Carolina University, Greenville, NC 27285, USA.
| | - Fadi A Issa
- Department of Biology, East Carolina University, Greenville, NC 27285, USA.
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13
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Quintana L, Jalabert C, Fokidis HB, Soma KK, Zubizarreta L. Neuroendocrine Mechanisms Underlying Non-breeding Aggression: Common Strategies Between Birds and Fish. Front Neural Circuits 2021; 15:716605. [PMID: 34393727 PMCID: PMC8358322 DOI: 10.3389/fncir.2021.716605] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/06/2021] [Indexed: 11/13/2022] Open
Abstract
Aggression is an adaptive behavior that plays an important role in gaining access to limited resources. Aggression may occur uncoupled from reproduction, thus offering a valuable context to further understand its neural and hormonal regulation. This review focuses on the contributions from song sparrows (Melospiza melodia) and the weakly electric banded knifefish (Gymnotus omarorum). Together, these models offer clues about the underlying mechanisms of non-breeding aggression, especially the potential roles of neuropeptide Y (NPY) and brain-derived estrogens. The orexigenic NPY is well-conserved between birds and teleost fish, increases in response to low food intake, and influences sex steroid synthesis. In non-breeding M. melodia, NPY increases in the social behavior network, and NPY-Y1 receptor expression is upregulated in response to a territorial challenge. In G. omarorum, NPY is upregulated in the preoptic area of dominant, but not subordinate, individuals. We hypothesize that NPY may signal a seasonal decrease in food availability and promote non-breeding aggression. In both animal models, non-breeding aggression is estrogen-dependent but gonad-independent. In non-breeding M. melodia, neurosteroid synthesis rapidly increases in response to a territorial challenge. In G. omarorum, brain aromatase is upregulated in dominant but not subordinate fish. In both species, the dramatic decrease in food availability in the non-breeding season may promote non-breeding aggression, via changes in NPY and/or neurosteroid signaling.
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Affiliation(s)
- Laura Quintana
- Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Ministerio de Educación y Cultura, Montevideo, Uruguay
| | - Cecilia Jalabert
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada
| | - H Bobby Fokidis
- Department of Biology, Rollins College, Winter Park, FL, United States
| | - Kiran K Soma
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada.,Department of Psychology, The University of British Columbia, Vancouver, BC, Canada
| | - Lucia Zubizarreta
- Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Ministerio de Educación y Cultura, Montevideo, Uruguay.,Laboratorio de Neurofisiología Celular y Sináptica, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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14
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Goymann W, Schwabl H. The tyranny of phylogeny-A plea for a less dogmatic stance on two-species comparisons: Funding bodies, journals and referees discourage two- or few-species comparisons, but such studies provide essential insights complementary to phylogenetic comparative studies. Bioessays 2021; 43:e2100071. [PMID: 34155665 DOI: 10.1002/bies.202100071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/04/2021] [Accepted: 06/08/2021] [Indexed: 11/11/2022]
Abstract
Phylogenetically controlled studies across multiple species correct for taxonomic confounds in physiological performance traits. Therefore, they are preferred over comparisons of two or few closely-related species. Funding bodies, referees and journal editors nowadays often even reject to consider detailed comparisons of two or few closely related species. Here, we plea for a less dogmatic stance on such comparisons, because phylogenetic studies come with their own limitations similar in magnitude as those of two-species comparisons. Two-species comparisons are particularly relevant and instructive for understanding physiological pathways and de novo mutations in three contexts: in a purely mechanistic context, when differences in the regulation of a trait are the focus of investigation, when a physiological trait lacks a direct connection to fitness, and when physiological measures cannot easily be standardized among laboratories. In conclusion, phylogenetic comparative and two-species studies have different strengths and weaknesses and combining these complementary approaches will help integrating biology.
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Affiliation(s)
- Wolfgang Goymann
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Hubert Schwabl
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
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15
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Baran NM, Streelman JT. Ecotype differences in aggression, neural activity and behaviorally relevant gene expression in cichlid fish. GENES BRAIN AND BEHAVIOR 2020; 19:e12657. [PMID: 32323443 DOI: 10.1111/gbb.12657] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/18/2022]
Abstract
In Lake Malawi, two ecologically distinct lineages of cichlid fishes (rock- vs sand-dwelling ecotypes, each comprised of over 200 species) evolved within the last million years. The rock-dwelling species (Mbuna) are aggressively territorial year-round and males court and spawn with females over rocky substrate. In contrast, males of sand-dwelling species are not territorial and instead aggregate on seasonal breeding leks in which males construct courtship "bowers" in the sand. However, little is known about how phenotypic variation in aggression is produced by the genome. In this study, we first quantify and compare behavior in seven cichlid species, demonstrating substantial ecotype and species differences in unconditioned mirror-elicited aggression. Second, we compare neural activity in mirror-elicited aggression in two representative species, Mchenga conophoros (sand-dwelling) and Petrotilapia chitimba (rock-dwelling). Finally, we compare gene expression patterns between these two species, specifically within neurons activated during mirror aggression. We identified a large number of genes showing differential expression in mirror-elicited aggression, as well as many genes that differ between ecotypes. These genes, which may underly species differences in behavior, include several neuropeptides, genes involved in the synthesis of steroid hormones and neurotransmitter activity. This work lays the foundation for future experiments using this emerging genetic model system to investigate the genomic basis of evolved species differences in both brain and behavior.
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Affiliation(s)
- Nicole M Baran
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA.,Department of Psychology, Emory University, Atlanta, Georgia, USA
| | - J Todd Streelman
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA.,The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
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16
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Cunha AAP, Partridge CG, Knapp R, Neff BD. Androgen and prolactin manipulation induces changes in aggressive and nurturing behavior in a fish with male parental care. Horm Behav 2019; 116:104582. [PMID: 31445012 DOI: 10.1016/j.yhbeh.2019.104582] [Citation(s) in RCA: 7] [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: 04/25/2019] [Revised: 07/29/2019] [Accepted: 08/20/2019] [Indexed: 11/26/2022]
Abstract
Parental care can include two general types of behavior: (1) aggressive behavior, which is used to defend offspring from predators; and (2) nurturing behavior, which is used to provide offspring with environmental conditions or resources necessary for survival. Many studies have implicated androgens in promoting aggressive behavior and prolactin in promoting nurturing behavior. We experimentally manipulated these hormones to investigate their effects on parental care behavior in bluegill (Lepomis macrochirus). Parental males, which provide sole care to the developing eggs and larvae, received an implant with an androgen (11-ketotestosterone [11-KT]), an androgen antagonist (flutamide), prolactin, a prolactin-release inhibitor (bromocriptine), or castor oil (placebo). We found that 11-KT implants led to a significant increase in the frequency of aggressive behavior directed towards a simulated brood predator, and were associated with a nearly significant decrease in the frequency of nurturing behavior directed towards the developing eggs. In contrast, prolactin implants were associated with a significant increase in the frequency of nurturing behavior, but also reduced the frequency of aggressive behavior directed towards the simulated brood predator. These results suggest a hormone-mediated mechanistic trade-off between nurturing and aggressive behavior, whereby parental males are unable to be both highly nurturing and highly aggressive.
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Affiliation(s)
- Adriano A P Cunha
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Charlyn G Partridge
- Annis Water Resources Institute, Grand Valley State University, Muskegon 49441, MI, USA
| | - Rosemary Knapp
- Department of Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Bryan D Neff
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada.
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17
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Lipshutz SE, George EM, Bentz AB, Rosvall KA. Evaluating testosterone as a phenotypic integrator: From tissues to individuals to species. Mol Cell Endocrinol 2019; 496:110531. [PMID: 31376416 PMCID: PMC6731036 DOI: 10.1016/j.mce.2019.110531] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 06/14/2019] [Accepted: 07/30/2019] [Indexed: 12/19/2022]
Abstract
Hormones have the potential to bring about rapid phenotypic change; however, they are highly conserved over millions of years of evolution. Here, we examine the evolution of hormone-mediated phenotypes, and the extent to which regulation is achieved via independence or integration of the many components of endocrine systems. We focus on the sex steroid testosterone (T), its cognate receptor (androgen receptor) and related endocrine components. We pose predictions about the mechanisms underlying phenotypic integration, including coordinated sensitivity to T within and among tissues and along the HPG axis. We then assess these predictions with case studies from wild birds, asking whether gene expression related to androgenic signaling naturally co-varies among individuals in ways that would promote phenotypic integration. Finally, we review how mechanisms of integration and independence vary over developmental or evolutionary time, and we find limited support for integration.
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Affiliation(s)
- S E Lipshutz
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.
| | - E M George
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, 47405, USA
| | - A B Bentz
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, 47405, USA
| | - K A Rosvall
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, 47405, USA
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18
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Zhao X, Fuxjager MJ, McLamore Q, Marler CA. Rapid effects of testosterone on social decision-making in a monogamous California mice (Peromyscus californicus). Horm Behav 2019; 115:104544. [PMID: 31220461 DOI: 10.1016/j.yhbeh.2019.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 06/14/2019] [Accepted: 06/16/2019] [Indexed: 01/27/2023]
Abstract
Social animals must cope with challenges and opportunities by adjusting how they react to a salient stimulus. Here we use California mice (Peromyscus californicus) and investigate the mechanisms underlying social decision-making by studying (i) rapid effects of testosterone (T) pulses on a male's decisions to approach a novel male (challenge) versus a receptive female (opportunity), and (ii) whether social experience shapes how such effects are manifested. In Experiment 1, we found that sexually naïve males administered saline injections preferentially approached unfamiliar females over unfamiliar males, in contrast, 10 min after receiving a single T-injection, males expressed a preference for approaching unfamiliar males. Such an effect of T only occurred in sexually naïve males, but not pair-bonded males, suggesting that the rapid effects of T on approach behavior may rely on the pair-bonding experiences. Experiment 2 investigated social decision-making across three repeated exposures to the challenge/opportunity situations. Only the initial decision, approach to the challenge, predicted future aggressive behaviors, and such an effect relied on the rapid actions of T. We also found that experience with the controlled challenge situation (the male intruder was restrained behind a wire mesh) dampened the approach to the male side (potential threat) when later exposed to the same conditions. This suggests that a resident's motivation to defend against a threatening individual may decrease as the threat posed by the "neighbors" is reduced. Overall rapid effects of post-encounter T pulses may play important roles in influencing behavioral decisions during social interactions.
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Affiliation(s)
- Xin Zhao
- Department of Psychology, University of Wisconsin, Madison, WI 53706, USA.
| | - Matthew J Fuxjager
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Quinnehtukqut McLamore
- Department of Psychology and Brain Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Catherine A Marler
- Department of Psychology, University of Wisconsin, Madison, WI 53706, USA
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19
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Elliott SM, Route WT, DeCicco LA, VanderMeulen DD, Corsi SR, Blackwell BR. Contaminants in bald eagles of the upper Midwestern U.S.: A framework for prioritizing future research based on in-vitro bioassays. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 244:861-870. [PMID: 30469280 PMCID: PMC6662187 DOI: 10.1016/j.envpol.2018.10.093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/19/2018] [Accepted: 10/19/2018] [Indexed: 05/15/2023]
Abstract
Several organic contaminants (OCs) have been detected in bald eagle (Haliaeetus leucocephalus) nestling (eaglet) plasma in the upper Midwestern United States. Despite frequent and relatively high concentrations of OCs in eaglets, little is understood about potential biological effects associated with exposure. We screened an existing database of OC concentrations in eaglet plasma collected from the Midwestern United States against bioactivity information from the ToxCast database. ToxCast bioactivity information consists of concentrations expected to elicit responses across a range of biological space (e.g. cellular, developmental, etc.) obtained from a series of high throughput assays. We calculated exposure-activity ratios (EAR) by calculating the ratio of plasma concentrations to concentrations available in ToxCast. Bioactivity data were not available for all detected OCs. Therefore, our analysis provides estimates of potential bioactivity for 19 of the detected OCs in eaglet plasma. Perfluorooctanesulfonic acid (PFOS) EAR values were consistently the highest among all study areas. Maximum EAR values were ≥1 for PFOS, perfluorononanoic acid, and bisphenol A in 99.7, 0.53 and 0.26% of samples, indicating that some plasma concentrations were greater than what may be expected to elicit biological responses. About 125 gene targets, indicative of specific biological pathways, were identified as potentially being affected. Inhibition of several CYP genes, involved in xenobiotic metabolism, were most consistently identified. Other identified biological responses have potential implications for motor coordination, cardiac functions, behavior, and blood circulation. However, it is unclear what these results mean for bald eagles, given that ToxCast data are generated using mammalian-based endpoints. Despite uncertainties and limitations, this method of screening environmental data can be useful for informing future monitoring or research focused on understanding the occurrence and effects of OCs in bald eagles and other similarly-positioned trophic species.
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Affiliation(s)
- Sarah M Elliott
- U.S. Geological Survey, 2280 Woodale Drive, Mounds View, MN, 55112, United States.
| | - William T Route
- U.S. National Park Service, Great Lakes Inventory & Monitoring Network, 2800 Lake Shore Drive East, Ashland, WI, 54806, United States.
| | - Laura A DeCicco
- U.S. Geological Survey, 8505 Research Way, Middleton, WI, 53562, United States.
| | - David D VanderMeulen
- U.S. National Park Service, Great Lakes Inventory & Monitoring Network, 2800 Lake Shore Drive East, Ashland, WI, 54806, United States.
| | - Steven R Corsi
- U.S. Geological Survey, 8505 Research Way, Middleton, WI, 53562, United States.
| | - Brett R Blackwell
- U.S. Environmental Protection Agency, 6201 Congdon Boulevard, Duluth, MN, 55804, United States.
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20
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Shevchouk OT, Ghorbanpoor S, Smith E, Liere P, Schumacher M, Ball GF, Cornil CA, Balthazart J. Behavioral evidence for sex steroids hypersensitivity in castrated male canaries. Horm Behav 2018; 103:80-96. [PMID: 29909262 DOI: 10.1016/j.yhbeh.2018.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 06/05/2018] [Accepted: 06/10/2018] [Indexed: 12/30/2022]
Abstract
In seasonally breeding songbirds such as canaries, singing behavior is predominantly under the control of testosterone and its metabolites. Short daylengths in the fall that break photorefractoriness are followed by increasing daylengths in spring that activate singing via both photoperiodic and hormonal mechanisms. However, we observed in a group of castrated male Fife fancy canaries maintained for a long duration under a short day photoperiod a large proportion of subjects that sang at high rates. This singing rate was not correlated with variation in the low circulating concentrations of testosterone. Treatment of these actively singing castrated male canaries with a combination of an aromatase inhibitor (ATD) and an androgen receptor blocker (flutamide) only marginally decreased this singing activity as compared to control untreated birds and did not affect various measures of song quality. The volumes of HVC and of the medial preoptic nucleus (POM) were also unaffected by these treatments but were relatively large and similar to volumes in testosterone-treated males. In contrast, peripheral androgen-sensitive structures such as the cloacal protuberance and syrinx mass were small, similar to what is observed in castrates. Together these data suggest that after a long-term steroid deprivation singing behavior can be activated by very low concentrations of testosterone. Singing normally depends on the activation by testosterone and its metabolites of multiple downstream neurochemical systems such as catecholamines, nonapeptides or opioids. These transmitter systems might become hypersensitive to steroid action after long term castration as they probably are at the end of winter during the annual cycle in seasonally breeding temperate zone species.
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Affiliation(s)
| | | | - Ed Smith
- Department of Psychology, University of Maryland, College Park, MD 20742, United States of America
| | - Philippe Liere
- INSERM UMR 1195 and Université Paris Sud and University Paris-Saclay, Le Kremlin-Bicêtre Cedex, France
| | - Michael Schumacher
- INSERM UMR 1195 and Université Paris Sud and University Paris-Saclay, Le Kremlin-Bicêtre Cedex, France
| | - Gregory F Ball
- Department of Psychology, University of Maryland, College Park, MD 20742, United States of America
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21
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Hood S, Amir S. Biological Clocks and Rhythms of Anger and Aggression. Front Behav Neurosci 2018; 12:4. [PMID: 29410618 PMCID: PMC5787107 DOI: 10.3389/fnbeh.2018.00004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/09/2018] [Indexed: 12/15/2022] Open
Abstract
The body’s internal timekeeping system is an under-recognized but highly influential force in behaviors and emotions including anger and reactive aggression. Predictable cycles or rhythms in behavior are expressed on several different time scales such as circadian (circa diem, or approximately 24-h rhythms) and infradian (exceeding 24 h, such as monthly or seasonal cycles). The circadian timekeeping system underlying rhythmic behaviors in mammals is constituted by a network of clocks distributed throughout the brain and body, the activity of which synchronizes to a central pacemaker, or master clock. Our daily experiences with the external environment including social activity strongly influence the exact timing of this network. In the present review, we examine evidence from a number of species and propose that anger and reactive aggression interact in multiple ways with circadian clocks. Specifically, we argue that: (i) there are predictable rhythms in the expression of aggression and anger; (ii) disruptions of the normal functioning of the circadian system increase the likelihood of aggressive behaviors; and (iii) conversely, chronic expression of anger can disrupt normal rhythmic cycles of physiological activities and create conditions for pathologies such as cardiovascular disease to develop. Taken together, these observations suggest that a comprehensive perspective on anger and reactive aggression must incorporate an understanding of the role of the circadian timing system in these intense affective states.
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Affiliation(s)
- Suzanne Hood
- Department of Psychology, Bishop's University, Sherbrooke, QC, Canada
| | - Shimon Amir
- Department of Psychology, Concordia University, Montreal, QC, Canada
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22
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Fuxjager MJ, Miles MC, Goller F, Petersen J, Yancey J. Androgens Support Male Acrobatic Courtship Behavior by Enhancing Muscle Speed and Easing the Severity of Its Tradeoff With Force. Endocrinology 2017; 158:4038-4046. [PMID: 28938418 DOI: 10.1210/en.2017-00599] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/23/2017] [Indexed: 01/08/2023]
Abstract
Steroid hormone action in the brain regulates many animals' elaborate social displays used for courtship and competition, but it is increasingly recognized that the periphery may also be a site for potent steroidal modulation of complex behavior. However, the mechanisms of such "bottom-up" regulation of behavioral outflow are largely unclear. To study this problem, we examined how androgenic sex hormones act through the skeletal muscular system to mediate elaborate courtship acrobatics in a tropical bird called the golden-collared manakin. As part of their display, males snap their wings together above their backs at rates that are at least 2× faster than the normal wing-beat frequency used for flight. This behavior, called the roll-snap, is actuated by repeatedly activating a humeral retractor muscle-the scapulohumeralis caudalis (SH)-which produces contraction-relaxation cycling speeds similar to the "superfast" muscles of other taxa. We report that endogenous androgenic activation of androgen receptor (AR) sustains this muscle's exceptionally rapid contractile kinetics, allowing the tissue to generate distinct wing movements at oscillation frequencies >100 Hz. We also show that these effects are rooted in an AR-dependent increase to contractile velocity, which incurs no detectable cost to force generation. Thus, AR enhances SH speed necessary for courtship display performance while avoiding the expected tradeoff with strength that could otherwise negatively influence aspects of flight. Peripheral AR therefore not only sets up the muscular system to perform a complex wing display, but does so in a way that balances the functional requirements of this muscle for other life-sustaining behavior.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Meredith C Miles
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Franz Goller
- Department of Biology, University of Utah, Salt Lake City, Utah 84112
| | - John Petersen
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Julia Yancey
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109
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23
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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.
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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
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24
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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.
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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
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25
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Wacker DW, Khalaj S, Jones LJ, Champion TL, Davis JE, Meddle SL, Wingfield JC. Dehydroepiandrosterone Heightens Aggression and Increases Androgen Receptor and Aromatase mRNA Expression in the Brain of a Male Songbird. J Neuroendocrinol 2016; 28. [PMID: 27805753 PMCID: PMC5333462 DOI: 10.1111/jne.12443] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/04/2016] [Accepted: 10/30/2016] [Indexed: 01/09/2023]
Abstract
Dehydroepiandrosterone (DHEA) is a testosterone/oestrogen precursor and known modulator of vertebrate aggression. Male song sparrows (Melospiza melodia morphna) show high aggression during breeding and nonbreeding life-history stages when circulating DHEA levels are high, and low aggression during molt when DHEA levels are low. We previously showed that androgen receptor and aromatase mRNA expression are higher during breeding and/or nonbreeding in brain regions associated with reproductive and aggressive behaviour, although the potential role of DHEA in mediating these seasonal changes remained unclear. In the present study, nonbreeding male song sparrows were captured and held in the laboratory under short days (8 : 16 h light/dark cycle) and implanted with s.c. DHEA-filled or empty (control) implants for 14 days. DHEA implants increased aggression in a laboratory-based simulated territorial intrusion. Brains of DHEA-implanted birds showed higher aromatase mRNA expression in the preoptic area (POA) and higher androgen receptor mRNA expression in the periventricular nucleus of the medial striatum (pvMSt) and ventromedial nucleus of the hypothalamus. The DHEA-induced increases in aromatase expression in the POA and androgen receptor expression in the pvMSt are consistent with previously reported seasonal increases in these markers associated with naturally elevated DHEA levels. This suggests that DHEA facilitates seasonal increases in aggression in nonbreeding male song sparrows by up-regulating steroid signalling/synthesis machinery in a brain region-specific fashion.
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Affiliation(s)
- D. W. Wacker
- School of STEM (Division of Biological Sciences)University of Washington BothellBothellWAUSA
| | - S. Khalaj
- School of STEM (Division of Biological Sciences)University of Washington BothellBothellWAUSA
| | - L. J. Jones
- School of STEM (Division of Biological Sciences)University of Washington BothellBothellWAUSA
| | | | - J. E. Davis
- Biology DepartmentRadford UniversityRadfordVAUSA
| | - S. L. Meddle
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghEdinburghUK
| | - J. C. Wingfield
- College of Biological SciencesUniversity of California DavisDavisCAUSA
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26
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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
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Heimovics SA, Prior NH, Ma C, Soma KK. Rapid Effects of an Aggressive Interaction on Dehydroepiandrosterone, Testosterone and Oestradiol Levels in the Male Song Sparrow Brain: a Seasonal Comparison. J Neuroendocrinol 2016; 28:12345. [PMID: 26648568 DOI: 10.1111/jne.12345] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/10/2015] [Accepted: 11/27/2015] [Indexed: 12/13/2022]
Abstract
Across vertebrates, aggression is robustly expressed during the breeding season when circulating testosterone is elevated, and testosterone activates aggression either directly or after aromatisation into 17β-oestradiol (E2 ) in the brain. In some species, such as the song sparrow, aggressive behaviour is also expressed at high levels during the nonbreeding season, when circulating testosterone is non-detectable. At this time, the androgen precursor dehydroepiandrosterone (DHEA) is metabolised within the brain into testosterone and/or E2 to promote aggression. In the present study, we used captive male song sparrows to test the hypothesis that an acute agonistic interaction during the nonbreeding season, but not during the breeding season, would alter steroid levels in the brain. Nonbreeding and breeding subjects were exposed to either a laboratory simulated territorial intrusion (L-STI) or an empty cage for only 5 min. Immediately afterwards, the brain was rapidly collected and flash frozen. The Palkovits punch technique was used to microdissect specific brain regions implicated in aggressive behaviour. Solid phase extraction followed by radioimmunoassay was used to quantify DHEA, testosterone and E2 in punches. Overall, levels of DHEA, testosterone and E2 were higher in brain tissue than in plasma. Local testosterone and E2 levels in the preoptic area, anterior hypothalamus and nucleus taeniae of the amygdala were significantly higher in the breeding season than the nonbreeding season and were not affected by the L-STI. Unexpectedly, subjects that were dominant in the L-STI had lower levels of DHEA in the anterior hypothalamus and medial striatum in both seasons and lower levels of DHEA in the nucleus taeniae of the amygdala in the breeding season only. Taken together, these data suggest that local levels of DHEA in the brain are very rapidly modulated by social interactions in a context and region-specific pattern.
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Affiliation(s)
- S A Heimovics
- Department of Biology, University of St. Thomas, St Paul, MN, USA
| | - N H Prior
- Department of Psychology, University of British Columbia, Vancouver, Canada
| | - C Ma
- Department of Psychology, University of British Columbia, Vancouver, Canada
| | - K K Soma
- Department of Psychology, University of British Columbia, Vancouver, Canada
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28
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delBarco-Trillo J, Greene LK, Goncalves IB, Fenkes M, Wisse JH, Drewe JA, Manser MB, Clutton-Brock T, Drea CM. Beyond aggression: Androgen-receptor blockade modulates social interaction in wild meerkats. Horm Behav 2016; 78:95-106. [PMID: 26545817 DOI: 10.1016/j.yhbeh.2015.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 11/01/2015] [Accepted: 11/02/2015] [Indexed: 01/26/2023]
Abstract
In male vertebrates, androgens are inextricably linked to reproduction, social dominance, and aggression, often at the cost of paternal investment or prosociality. Testosterone is invoked to explain rank-related reproductive differences, but its role within a status class, particularly among subordinates, is underappreciated. Recent evidence, especially for monogamous and cooperatively breeding species, suggests broader androgenic mediation of adult social interaction. We explored the actions of androgens in subordinate, male members of a cooperatively breeding species, the meerkat (Suricata suricatta). Although male meerkats show no rank-related testosterone differences, subordinate helpers rarely reproduce. We blocked androgen receptors, in the field, by treating subordinate males with the antiandrogen, flutamide. We monitored androgen concentrations (via baseline serum and time-sequential fecal sampling) and recorded behavior within their groups (via focal observation). Relative to controls, flutamide-treated animals initiated less and received more high-intensity aggression (biting, threatening, feeding competition), engaged in more prosocial behavior (social sniffing, grooming, huddling), and less frequently initiated play or assumed a 'dominant' role during play, revealing significant androgenic effects across a broad range of social behavior. By contrast, guarding or vigilance and measures of olfactory and vocal communication in subordinate males appeared unaffected by flutamide treatment. Thus, androgens in male meerkat helpers are aligned with the traditional trade-off between promoting reproductive and aggressive behavior at a cost to affiliation. Our findings, based on rare endocrine manipulation in wild mammals, show a more pervasive role for androgens in adult social behavior than is often recognized, with possible relevance for understanding tradeoffs in cooperative systems.
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Affiliation(s)
- Javier delBarco-Trillo
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Department of Evolutionary Anthropology, Duke University, Durham, USA; School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Lydia K Greene
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Department of Evolutionary Anthropology, Duke University, Durham, USA; University Program in Ecology, Duke University, Durham, USA
| | - Ines Braga Goncalves
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Miriam Fenkes
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Jillian H Wisse
- Department of Evolutionary Anthropology, Duke University, Durham, USA
| | - Julian A Drewe
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Royal Veterinary College, University of London, London, UK
| | - Marta B Manser
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland; Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Tim Clutton-Brock
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Mammal Research Institute, University of Pretoria, Pretoria, South Africa; Department of Zoology, University of Cambridge, Cambridge, UK
| | - Christine M Drea
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa; Department of Evolutionary Anthropology, Duke University, Durham, USA; University Program in Ecology, Duke University, Durham, USA; Department of Biology, Duke University, Durham, USA.
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Fuxjager MJ, Lee JH, Chan TM, Bahn JH, Chew JG, Xiao X, Schlinger BA. Research Resource: Hormones, Genes, and Athleticism: Effect of Androgens on the Avian Muscular Transcriptome. Mol Endocrinol 2016; 30:254-71. [PMID: 26745669 DOI: 10.1210/me.2015-1270] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Male vertebrate social displays vary from physically simple to complex, with the latter involving exquisite motor command of the body and appendages. Studies of these displays have, in turn, provided substantial insight into neuromotor mechanisms. The neotropical golden-collared manakin (Manacus vitellinus) has been used previously as a model to investigate intricate motor skills because adult males of this species perform an acrobatic and androgen-dependent courtship display. To support this behavior, these birds express elevated levels of androgen receptors (AR) in their skeletal muscles. Here we use RNA sequencing to explore how testosterone (T) modulates the muscular transcriptome to support male manakin courtship displays. In addition, we explore how androgens influence gene expression in the muscles of the zebra finch (Taenopygia guttata), a model passerine bird with a limited courtship display and minimal muscle AR. We identify androgen-dependent, muscle-specific gene regulation in both species. In addition, we identify manakin-specific effects that are linked to muscle use during the manakin display, including androgenic regulation of genes associated with muscle fiber contractility, cellular homeostasis, and energetic efficiency. Overall, our results point to numerous genes and gene networks impacted by androgens in male birds, including some that underlie optimal muscle function necessary for performing acrobatic display routines. Manakins are excellent models to explore gene regulation promoting athletic ability.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jae-Hyung Lee
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Tak-Ming Chan
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jae Hoon Bahn
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jenifer G Chew
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Xinshu Xiao
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Barney A Schlinger
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
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30
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Hau M, Goymann W. Endocrine mechanisms, behavioral phenotypes and plasticity: known relationships and open questions. Front Zool 2015; 12 Suppl 1:S7. [PMID: 26816524 PMCID: PMC4722346 DOI: 10.1186/1742-9994-12-s1-s7] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Behavior of wild vertebrate individuals can vary in response to environmental or social factors. Such within-individual behavioral variation is often mediated by hormonal mechanisms. Hormones also serve as a basis for among-individual variations in behavior including animal personalities and the degree of responsiveness to environmental and social stimuli. How do relationships between hormones and behavioral traits evolve to produce such behavioral diversity within and among individuals? Answering questions about evolutionary processes generating among-individual variation requires characterizing how specific hormones are related to variation in specific behavioral traits, whether observed hormonal variation is related to individual fitness and, whether hormonal traits are consistent (repeatable) aspects of an individual's phenotype. With respect to within-individual variation, we need to improve our insight into the nature of the quantitative relationships between hormones and the traits they regulate, which in turn will determine how they may mediate behavioral plasticity of individuals. To address these questions, we review the actions of two steroid hormones, corticosterone and testosterone, in mediating changes in vertebrate behavior, focusing primarily on birds. In the first part, we concentrate on among-individual variation and present examples for how variation in corticosterone concentrations can relate to behaviors such as exploration of novel environments and parental care. We then review studies on correlations between corticosterone variation and fitness, and on the repeatability over time of corticosterone concentrations. At the end of this section, we suggest that further progress in our understanding of evolutionary patterns in the hormonal regulation of behavior may require, as one major tool, reaction norm approaches to characterize hormonal phenotypes as well as their responses to environments. In the second part, we discuss types of quantitative relationships between hormones and behavioral traits within individuals, using testosterone as an example. We review conceptual models for testosterone-behavior relationships and discuss the relevance of these models for within-individual plasticity in behavior. Next, we discuss approaches for testing the nature of quantitative relationships between testosterone and behavior, concluding that again reaction norm approaches might be a fruitful way forward. We propose that an integration of new tools, especially of reaction norm approaches into the field of behavioral endocrinology will allow us to make significant progress in our understanding of the mechanisms, the functional implications and the evolution of hormone–behavior relationships that mediate variation both within and among individuals. This knowledge will be crucial in light of already ongoing habitat alterations due to global change, as it will allow us to evaluate the mechanisms as well as the capacity of wild populations to adjust hormonally-mediated behaviors to altered environmental conditions.
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Affiliation(s)
- Michaela Hau
- Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., D-82319 Seewiesen, Germany; University of Konstanz, Department of Biology, Universitätsstraße 10, D-78464 Konstanz, Germany
| | - Wolfgang Goymann
- Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., D-82319 Seewiesen, Germany
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31
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Heimovics SA, Ferris JK, Soma KK. Non-invasive administration of 17β-estradiol rapidly increases aggressive behavior in non-breeding, but not breeding, male song sparrows. Horm Behav 2015; 69:31-8. [PMID: 25483754 DOI: 10.1016/j.yhbeh.2014.11.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 11/25/2014] [Accepted: 11/27/2014] [Indexed: 12/19/2022]
Abstract
17β-Estradiol (E2) acts in the brain via genomic and non-genomic mechanisms to influence physiology and behavior. There is seasonal plasticity in the mechanisms by which E2 activates aggression, and non-genomic mechanisms appear to predominate during the non-breeding season. Male song sparrows (Melospiza melodia) display E2-dependent territorial aggression throughout the year. Field studies show that song sparrow aggression during a territorial intrusion is similar in the non-breeding and breeding seasons, but aggression after an intrusion ends differs seasonally. Non-breeding males stop behaving aggressively within minutes whereas breeding males remain aggressive for hours. We hypothesize that this seasonal plasticity in the persistence of aggression relates to seasonal plasticity in E2 signaling. We used a non-invasive route of E2 administration to compare the non-genomic (within 20min) effects of E2 on aggressive behavior in captive non-breeding and breeding season males. E2 rapidly increased barrier contacts (attacks) during an intrusion by 173% in non-breeding season males only. Given that these effects were observed within 20min of E2 administration, they likely occurred via a non-genomic mechanism of action. The present data, taken together with past work, suggest that environmental cues associated with the non-breeding season influence the molecular mechanisms through which E2 influences behavior. In song sparrows, transient expression of aggressive behavior during the non-breeding season is highly adaptive: it minimizes energy expenditure and maximizes the amount of time available for foraging. In all, these data suggest the intriguing possibility that aggression in the non-breeding season may be activated by a non-genomic E2 mechanism due to the fitness benefits associated with rapid and transient expression of aggression.
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Affiliation(s)
- Sarah A Heimovics
- Department of Biology, University of St. Thomas, St. Paul, MN, USA; Neuroscience Program, University of St. Thomas, St. Paul, MN, USA.
| | - Jennifer K Ferris
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Kiran K Soma
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Department of Zoology, University of British Columbia, Vancouver, BC, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
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32
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Fokidis HB, Adomat HH, Kharmate G, Hosseini-Beheshti E, Guns ES, Soma KK. Regulation of local steroidogenesis in the brain and in prostate cancer: lessons learned from interdisciplinary collaboration. Front Neuroendocrinol 2015; 36:108-29. [PMID: 25223867 DOI: 10.1016/j.yfrne.2014.08.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 11/16/2022]
Abstract
Sex steroids play critical roles in the regulation of the brain and many other organs. Traditionally, researchers have focused on sex steroid signaling that involves travel from the gonads via the circulation to intracellular receptors in target tissues. This classic concept has been challenged, however, by the growing number of cases in which steroids are synthesized locally and act locally within diverse tissues. For example, the brain and prostate carcinoma were previously considered targets of gonadal sex steroids, but under certain circumstances, these tissues can upregulate their steroidogenic potential, particularly when circulating sex steroid concentrations are low. We review some of the similarities and differences between local sex steroid synthesis in the brain and prostate cancer. We also share five lessons that we have learned during the course of our interdisciplinary collaboration, which brought together neuroendocrinologists and cancer biologists. These lessons have important implications for future research in both fields.
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Affiliation(s)
- H Bobby Fokidis
- Department of Biology, Rollins College, Winter Park, FL 37289, USA; Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada.
| | - Hans H Adomat
- Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada
| | | | | | - Emma S Guns
- Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada; Department of Urological Sciences, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kiran K Soma
- Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Brain Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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33
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Laredo SA, Villalon Landeros R, Trainor BC. Rapid effects of estrogens on behavior: environmental modulation and molecular mechanisms. Front Neuroendocrinol 2014; 35:447-58. [PMID: 24685383 PMCID: PMC4175137 DOI: 10.1016/j.yfrne.2014.03.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 03/11/2014] [Accepted: 03/19/2014] [Indexed: 12/24/2022]
Abstract
Estradiol can modulate neural activity and behavior via both genomic and nongenomic mechanisms. Environmental cues have a major impact on the relative importance of these signaling pathways with significant consequences for behavior. First we consider how photoperiod modulates nongenomic estrogen signaling on behavior. Intriguingly, short days permit rapid effects of estrogens on aggression in both rodents and song sparrows. This highlights the importance of considering photoperiod as a variable in laboratory research. Next we review evidence for rapid effects of estradiol on ecologically-relevant behaviors including aggression, copulation, communication, and learning. We also address the impact of endocrine disruptors on estrogen signaling, such as those found in corncob bedding used in rodent research. Finally, we examine the biochemical mechanisms that may mediate rapid estrogen action on behavior in males and females. A common theme across these topics is that the effects of estrogens on social behaviors vary across different environmental conditions.
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Affiliation(s)
- Sarah A Laredo
- Animal Behavior Graduate Group, University of California, Davis, CA 95616, United States; Center for Neuroscience, University of California, Davis, CA 95616, United States; Department of Psychology, University of California, Davis, CA 95616, United States
| | - Rosalina Villalon Landeros
- Perinatal Research Laboratories, Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, United States
| | - Brian C Trainor
- Animal Behavior Graduate Group, University of California, Davis, CA 95616, United States; Center for Neuroscience, University of California, Davis, CA 95616, United States; Department of Psychology, University of California, Davis, CA 95616, United States.
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34
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Golinski A, Kubička L, John-Alder H, Kratochvíl L. Elevated testosterone is required for male copulatory behavior and aggression in Madagascar ground gecko (Paroedura picta). Gen Comp Endocrinol 2014; 205:133-41. [PMID: 24852349 DOI: 10.1016/j.ygcen.2014.05.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 05/01/2014] [Accepted: 05/06/2014] [Indexed: 11/22/2022]
Abstract
Elevated levels of gonadal androgens are often required for the expression of male-specific behavioral and morphological traits in all classes of vertebrates, including reptiles. Here, we tested the role of male gonadal androgens in the control of male sexual behavior, aggressive behavior, and size of the hemipenes in the gecko Paroedura picta. We performed hormonal manipulations involving castration with and without testosterone (T) replacement in males and application of exogenous T and ovariectomy in females. Castration suppressed sexual behavior and hemipenes size in males, and these effects were fully rescued by exogenous T. Sexual behavior and growth of the hemipenes were masculinized by male-typical levels of T in females, while ovariectomized females retained female-typical expression of these traits. These results indicate that the development of male sexual behavior in adult females does not require early or pubertal organization. Elevated T increased the likelihood of aggressive behavior directed toward a male intruder, but aggression occurred only rarely. Elevated T is necessary and sufficient for enlargement of the hemipenes and the expression of male sexual behavior in both males and females of Paroedura picta. In contrast to sexual behavior, the expression of aggressive behavior is apparently more dependent on other factors in addition to T itself.
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Affiliation(s)
- Alison Golinski
- Graduate Program in Endocrinology and Animal Biosciences, Rutgers University, 84 Lipman Drive, New Brunswick, NJ 08901, USA
| | - Lukáš Kubička
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, 128 43 Praha 2, Czech Republic.
| | - Henry John-Alder
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901, USA
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, 128 43 Praha 2, Czech Republic
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Fuxjager MJ, Longpre KM, Chew JG, Fusani L, Schlinger BA. Peripheral androgen receptors sustain the acrobatics and fine motor skill of elaborate male courtship. Endocrinology 2013; 154:3168-77. [PMID: 23782945 PMCID: PMC5393330 DOI: 10.1210/en.2013-1302] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Androgenic hormones regulate many aspects of animal social behavior, including the elaborate display routines on which many species rely for advertisement and competition. One way that this might occur is through peripheral effects of androgens, particularly on skeletal muscles that control complex movements and postures of the body and its limbs. However, the specific contribution of peripheral androgen-muscle interactions to the performance of elaborate behavioral displays in the natural world has never been examined. We study this issue in one of the only natural physiological models of animal acrobatics: the golden-collared manakin (Manacus vitellinus). In this tropical bird, males compete with each other and court females by producing firecracker-like wing- snaps and by rapidly dancing among saplings over the forest floor. To test how activation of peripheral androgen receptors (AR) influences this display, we treat reproductively active adult male birds with the peripherally selective antiandrogen bicalutamide (BICAL) and observe the effects of this manipulation on male display performance. We not only validate the peripheral specificity of BICAL in this species, but we also show that BICAL treatment reduces the frequency with which adult male birds perform their acrobatic display maneuvers and disrupts the overall structure and fine-scale patterning of these birds' main complex wing-snap sonation. In addition, this manipulation has no effect on the behavioral metrics associated with male motivation to display. Together, our findings help differentiate the various effects of peripheral and central AR on the performance of a complex sociosexual behavioral phenotype by indicating that peripheral AR can optimize the motor skills necessary for the production of an elaborate animal display.
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MESH Headings
- Androgen Receptor Antagonists/administration & dosage
- Androgen Receptor Antagonists/pharmacology
- Anilides/administration & dosage
- Anilides/pharmacology
- Animals
- Animals, Wild/growth & development
- Animals, Wild/physiology
- Avian Proteins/antagonists & inhibitors
- Avian Proteins/genetics
- Avian Proteins/metabolism
- Drug Implants
- Feathers/growth & development
- Feathers/metabolism
- Infusions, Subcutaneous
- Male
- Motor Skills/drug effects
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Nitriles/administration & dosage
- Nitriles/pharmacology
- Nonsteroidal Anti-Androgens/administration & dosage
- Nonsteroidal Anti-Androgens/pharmacology
- Panama
- Pigments, Biological/metabolism
- RNA, Messenger/metabolism
- Random Allocation
- Receptors, Androgen/chemistry
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Sexual Behavior, Animal/drug effects
- Songbirds/growth & development
- Songbirds/physiology
- Tosyl Compounds/administration & dosage
- Tosyl Compounds/pharmacology
- Trees
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Affiliation(s)
- Matthew J Fuxjager
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
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36
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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.
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Affiliation(s)
- Camila P Villavicencio
- Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str. 6a, D-82319 Seewiesen, Germany.
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37
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Bergeon Burns CM, Rosvall KA, Ketterson ED. Neural steroid sensitivity and aggression: comparing individuals of two songbird subspecies. J Evol Biol 2013; 26:820-31. [PMID: 23517519 PMCID: PMC3622748 DOI: 10.1111/jeb.12094] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/09/2012] [Accepted: 11/30/2012] [Indexed: 11/27/2022]
Abstract
Hormones coordinate the expression of complex phenotypes and thus may play important roles in evolutionary processes. When populations diverge in hormone-mediated phenotypes, differences may arise via changes in circulating hormones, sensitivity to hormones or both. Determining the relative importance of signal and sensitivity requires consideration of both inter- and intrapopulation variation in hormone levels, hormone sensitivity and phenotype, but such studies are rare, particularly among closely related taxa. We compared males of two subspecies of the dark-eyed junco (Junco hyemalis) for territorial aggression and associations among behaviour, circulating testosterone (T), and gene expression of androgen receptor (AR), aromatase (AROM) and oestrogen receptor α in three behaviourally relevant brain regions. Thus, we examined the degree to which evolution may shape behaviour via changes in plasma T as compared with key sex steroid binding/converting molecules. We found that the white-winged junco (J. h. aikeni) was more aggressive than the smaller, less ornamented Carolina junco (J. h. carolinensis). The subspecies did not differ in circulating testosterone, but did differ significantly in the abundance of AR and AROM mRNA in key areas of the brain. Within populations, both gene expression and circulating T co-varied significantly with individual differences in aggression. Notably, the differences identified between populations were opposite to those predicted by the patterns among individuals within populations. These findings suggest that hormone-phenotype relationships may evolve via multiple pathways, and that changes that have occurred over evolutionary time do not necessarily reflect standing physiological variation on which current evolutionary processes may act.
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Affiliation(s)
- C M Bergeon Burns
- Department of Biology and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
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38
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van Breukelen NA. Androgen receptor antagonist impairs courtship but not aggressive behavior in the monogamous cichlid, Amatitlania nigrofasciata. Horm Behav 2013; 63:527-32. [PMID: 23380161 DOI: 10.1016/j.yhbeh.2013.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 01/15/2013] [Accepted: 01/21/2013] [Indexed: 11/16/2022]
Abstract
Androgens, specifically 11-ketotestosterone, are hypothesized to be important in the expression of pre-spawning behaviors such as courtship and aggression in many teleost species. This experiment attempted to elucidate the roles of androgens in the expression of pre-spawning courtship and aggression in male convict cichlids (Amatitlania nigrofasciata). In a laboratory experiment, males were treated with either the androgen receptor antagonist flutamide or blank control and subsequently exposed to social conditions to stimulate inter-sexual courtship or intra-sexual aggression. Males treated with flutamide expressed significantly fewer courtship behaviors than control males but did not differ from control males in pre-spawning intra-sexual aggression. In a field experiment, males treated with flutamide expressed significantly less courtship behavior than males given blank capsules or unmanipulated control males, but did not differ from either set of control males in aggression towards conspecifics or overall aggression to con- and heterospecifics. These data suggest that androgens mediate pre-spawning courtship behavior but not pre-spawning aggression in this species.
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Affiliation(s)
- Natalie April van Breukelen
- Mount Aloysius College, Dept. of Science and Mathematics, 7373 Admiral Peary Highway, Cresson, PA 16630, USA.
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Apfelbeck B, Mortega KG, Kiefer S, Kipper S, Goymann W. Life-history and hormonal control of aggression in black redstarts: Blocking testosterone does not decrease territorial aggression, but changes the emphasis of vocal behaviours during simulated territorial intrusions. Front Zool 2013; 10:8. [PMID: 23433033 PMCID: PMC3636094 DOI: 10.1186/1742-9994-10-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 01/31/2013] [Indexed: 01/09/2023] Open
Abstract
INTRODUCTION Many studies in behavioural endocrinology attempt to link territorial aggression with testosterone, but the exact relationship between testosterone and territorial behaviour is still unclear and may depend on the ecology of a species. The degree to which testosterone facilitates territorial behaviour is particularly little understood in species that defend territories during breeding and outside the breeding season, when plasma levels of testosterone are low. Here we suggest that species that defend territories in contexts other than reproduction may have lost the direct regulation of territorial behaviour by androgens even during the breeding season. In such species, only those components of breeding territoriality that function simultaneously as sexually selected signals may be under control of sex steroids. RESULTS We investigated black redstarts (Phoenicurus ochruros), a species that shows periods of territoriality within and outside of the breeding season. We treated territorial males with an anti-androgen and an aromatase inhibitor during the breeding season to block both the direct and indirect effects of testosterone. Three and ten days after the treatment, implanted males were challenged with a simulated territorial intrusion. The treatment did not reduce the overall territorial response, but it changed the emphasis of territoriality: experimental males invested more in behaviours addressed directly towards the intruder, whereas placebo-treated males put most effort into their vocal response, a component of territoriality that may be primarily directed towards their mating partner rather than the male opponent. CONCLUSIONS In combination with previous findings, these data suggest that overall territoriality may be decoupled from testosterone in male black redstarts. However, high levels of testosterone during breeding may facilitate-context dependent changes in song.
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Affiliation(s)
- Beate Apfelbeck
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Eberhard-Gwinner-Str, 6a, Seewiesen, D-82319, Germany.
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40
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Rosvall KA, Bergeon Burns CM, Barske J, Goodson JL, Schlinger BA, Sengelaub DR, Ketterson ED. Neural sensitivity to sex steroids predicts individual differences in aggression: implications for behavioural evolution. Proc Biol Sci 2012; 279:3547-55. [PMID: 22673360 PMCID: PMC3396890 DOI: 10.1098/rspb.2012.0442] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 05/16/2012] [Indexed: 01/08/2023] Open
Abstract
Testosterone (T) regulates many traits related to fitness, including aggression. However, individual variation in aggressiveness does not always relate to circulating T, suggesting that behavioural variation may be more closely related to neural sensitivity to steroids, though this issue remains unresolved. To assess the relative importance of circulating T and neural steroid sensitivity in predicting behaviour, we measured aggressiveness during staged intrusions in free-living male and female dark-eyed juncos (Junco hyemalis). We compared aggressiveness to plasma T levels and to the abundance of androgen receptor (AR), aromatase (AROM) and oestrogen receptor alpha (ORα) mRNA in behaviourally relevant brain areas (avian medial amygdala, hypothalamus and song control regions). We also asked whether patterns of covariation among behaviour and endocrine parameters differed in males and females, anticipating that circulating T may be a better predictor of behaviour in males than in females. We found that circulating T related to aggressiveness only in males, but that gene expression for ORα, AR and AROM covaried with individual differences in aggressiveness in both sexes. These findings are among the first to show that individual variation in neural gene expression for three major sex steroid-processing molecules predicts individual variation in aggressiveness in both sexes in nature. The results have broad implications for our understanding of the mechanisms by which aggressive behaviour may evolve.
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Affiliation(s)
- K A Rosvall
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
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41
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Molecular identification of an androgen receptor and its changes in mRNA levels during 17α-methyltestosterone-induced sex reversal in the orange-spotted grouper Epinephelus coioides. Comp Biochem Physiol B Biochem Mol Biol 2012; 163:43-50. [DOI: 10.1016/j.cbpb.2012.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 04/19/2012] [Accepted: 04/23/2012] [Indexed: 11/22/2022]
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42
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Effects of castration on aggression and levels of serum sex hormones and their central receptors in mandarin voles (Microtus mandarinus). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 198:347-62. [DOI: 10.1007/s00359-012-0713-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 01/12/2012] [Accepted: 01/15/2012] [Indexed: 10/14/2022]
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43
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Rosvall KA. Intrasexual competition in females: evidence for sexual selection? Behav Ecol 2011; 22:1131-1140. [PMID: 22479137 PMCID: PMC3199163 DOI: 10.1093/beheco/arr106] [Citation(s) in RCA: 268] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 11/29/2010] [Accepted: 05/24/2011] [Indexed: 11/14/2022] Open
Abstract
In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female-female competition are sexually selected. This review uses female-female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes.
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Affiliation(s)
- Kimberly A Rosvall
- Department of Biology, Indiana University, Jordan Hall, Rm 142, 1001 E. 3rd Street, Bloomington, IN 47405, USA
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Hau M, Beebe K. Plastic endocrine regulation of year-round territorial aggression in tropical male spotted antbirds. Gen Comp Endocrinol 2011; 172:305-13. [PMID: 21447333 DOI: 10.1016/j.ygcen.2011.03.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 03/14/2011] [Accepted: 03/19/2011] [Indexed: 12/16/2022]
Abstract
Studies investigating the hormonal regulation of aggression often focus on the role of the steroid hormone testosterone (T). These studies have generally found an association in temperate zone species between T and male aggression in a reproductive context. However, in most temperate zone species seasonal variation in reproductive context cannot easily be separated from concomitant seasonal changes in other variables, including territory location and partner presence. Therefore, we investigated the hormonal regulation of territorial aggression in a tropical bird that breeds seasonally, but remains mated and territorial year-round. Free-living male spotted antbirds (Hylophylax n. naevioides) displayed similar aggressive behavior in the non-breeding, early, and middle breeding seasons when exposed to a simulated territorial intrusion (STI). Plasma T concentrations after STIs were low and seasonally invariant, but plasma dehydroepiandrosterone (DHEA) was elevated during the non-breeding season. Simultaneous administration of pharmacological inhibitors of androgenic and estrogenic actions during the non-breeding season was less effective in reducing aggressive behavior of captive males compared with a previous study conducted during the breeding season. Hence, in male spotted antbirds endocrine mechanisms appear to vary with reproductive context, both in DHEA concentrations and in the importance of T for regulating aggressive behavior. Furthermore, combining the current data with previous findings suggests that short-term increases in T during aggressive interactions in this tropical species are dependent on the context and the intensity of aggressive stimuli, regardless of season.
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Affiliation(s)
- Michaela Hau
- Max Planck Institute for Ornithology, Department of Migration and Immuno-Ecology, Radolfzell, Germany.
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45
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Fuxjager MJ, Montgomery JL, Marler CA. Species differences in the winner effect disappear in response to post-victory testosterone manipulations. Proc Biol Sci 2011; 278:3497-503. [PMID: 21490015 DOI: 10.1098/rspb.2011.0301] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Evolutionary processes can interact with the mechanisms of steroid hormone action to drive interspecific variation in behavioural output, yet the exact nature of these interactions is poorly understood. To investigate this issue, we compare the endocrine machinery underlying the winner effect (an ability to increase winning behaviour in response to past victories) in two closely related species of Peromyscus mice. Typically, after winning a fight, California mice (Peromyscus californicus) experience a testosterone (T) surge that helps enhance their future winning behaviour, whereas white-footed mice (Peromyscus leucopus) experience neither a T surge nor a change in subsequent winning behaviour. However, our results indicate that when the post-victory T response of male white-footed mice is phenotypically engineered to resemble that of California mice, individuals are capable of developing a strong and lasting winner effect. Moreover, this 'induced' winner effect in white-footed mice qualitatively matches the winner effect that develops naturally in California mice. Taken together, these findings suggest that white-footed mice have the physiological machinery necessary to form a robust winner effect comparable to that formed by California mice, but are unable to endogenously activate this machinery after achieving winning experiences. We speculate that evolutionary processes, like selection, operate on the physiological substrates that govern post-victory T release to guide divergence in the winner effect between these two species.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Wacker DW, Wingfield JC, Davis JE, Meddle SL. Seasonal changes in aromatase and androgen receptor, but not estrogen receptor mRNA expression in the brain of the free-living male song sparrow, Melospiza melodia morphna. J Comp Neurol 2010; 518:3819-35. [PMID: 20653036 DOI: 10.1002/cne.22426] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Free-living male song sparrows experience three annually repeating life history stages associated with differential expression of sex steroid-dependent reproductive and aggressive behavior. In the breeding stage, they display reproductive and aggressive behavior and have elevated circulating testosterone levels. During molt, males show little or no aggression and no reproductive behavior, and have basal levels of circulating testosterone. In the non-breeding stage, they display high levels of aggression and no reproductive behavior, and have basal levels of circulating testosterone. In order to understand more fully the neural regulation of seasonal aggressive and reproductive behavior, birds were collected during all three life history stages, and levels of neural aromatase, androgen receptor (AR), and estrogen receptor alpha (ERalpha) and beta (ERbeta) mRNA expression were measured. Breeding males had the highest levels of aromatase expression in both the preoptic area (POA) and medial preoptic area/medial bed nucleus of the stria terminalis (mPOA/BSTm), and the highest AR expression levels in the POA, consistent with the well-established role these regions play in the regulation of male reproductive behavior. Aromatase expression in the ventromedial nucleus of the hypothalamus (VMH) was higher during breeding and non-breeding compared with molt, suggesting that the VMH may play a role in the estrogen-dependent regulation of aggression in this species. AR expression also varied in medial HVC and pvMSt, a newly described periventricular region in the medial striatum. ERalpha and ERbeta mRNA expression did not vary seasonally in any brain region examined, suggesting that estrogen-dependent changes in behavior are mediated by differences in neural estrogen synthesis.
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Affiliation(s)
- Douglas W Wacker
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom.
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47
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Winning territorial disputes selectively enhances androgen sensitivity in neural pathways related to motivation and social aggression. Proc Natl Acad Sci U S A 2010; 107:12393-8. [PMID: 20616093 DOI: 10.1073/pnas.1001394107] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Winning aggressive disputes can enhance future fighting ability and the desire to seek out additional contests. In some instances, these effects are long lasting and vary in response to the physical location of a fight. Thus, in principle, winning aggressive encounters may cause long-term and context-dependent changes to brain areas that control the output of antagonistic behavior or the motivation to fight (or both). We examined this issue in the territorial California mouse (Peromyscus californicus) because males of this species are more likely to win fights after accruing victories in their home territory but not after accruing victories in unfamiliar locations. Using immunocytochemistry and real-time quantitative PCR, we found that winning fights either at home or away increases the expression of androgen receptors (AR) in the medial anterior bed nucleus of the stria terminalis, a key brain area that controls social aggression. We also found that AR expression in brain regions that mediate motivation and reward, nucleus accumbens (NAcc) and ventral tegmental area (VTA), increases only in response to fights in the home territory. These effects of winning were likely exclusive to the neural androgenic system because they have no detectible impact on the expression of progestin receptors. Finally, we demonstrated that the observed changes in androgen sensitivity in the NAcc and VTA are positively associated with the ability to win aggressive contests. Thus, winning fights can change brain phenotype in a manner that likely promotes future victory and possibly primes neural circuits that motivate individuals to fight.
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Koolhaas JM, de Boer SF, Coppens CM, Buwalda B. Neuroendocrinology of coping styles: towards understanding the biology of individual variation. Front Neuroendocrinol 2010; 31:307-21. [PMID: 20382177 DOI: 10.1016/j.yfrne.2010.04.001] [Citation(s) in RCA: 590] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 04/01/2010] [Accepted: 04/04/2010] [Indexed: 01/29/2023]
Abstract
Individual variation in behavior and physiology is a widespread and ecologically functional phenomenon in nature in virtually all vertebrate species. Due to domestication of laboratory animals, studies may suffer from a strong selection bias. This paper summarizes behavioral, neuroendocrine and neurobiological studies using the natural individual variation in rats and mice. Individual behavioral characteristics appear to be consistent over time and across situations. The individual variation has at least two dimensions in which the quality of the response to a challenging condition (coping style) is independent from the quantity of that response (stress reactivity). The neurobiology reveals important differences in the homeostatic control of the serotonergic neuron and the neuropeptides vasopressin and oxytocin in relation to coping style. It is argued that a careful exploitation of the broad natural and biologically functional individual variation in behavior and physiology may help in developing better animal models for understanding individual disease vulnerability.
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Affiliation(s)
- J M Koolhaas
- Dept. of Behavioural Physiology, University Groningen, 9750 AA Haren, The Netherlands.
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