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Rasoloharijaona S, Randrianambinina B, Radespiel U. Evidence for female dominance in the Milne-Edwards' sportive lemur (Lepilemur edwardsi). Am J Primatol 2024:e23658. [PMID: 38924599 DOI: 10.1002/ajp.23658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 06/13/2024] [Accepted: 06/16/2024] [Indexed: 06/28/2024]
Abstract
Female dominance over males is more frequent in Malagasy lemurs than in other primate clades, but patterns of female-male dominance vary among species, and few data are available for one particularly species-rich genus, Lepilemur. We investigated the types, temporal distribution, and outcome of female-male agonistic conflicts in the Milne-Edwards' sportive lemur (Lepilemur edwardsi). Ten L. edwardsi belonging to five social units were equipped with radio collars and observed during 79 focal follows between May and November 1998. We quantified agonistic conflicts, monthly conflict rates, and documented the winner and context for all conflicts. Female-male agonistic conflicts (N = 162) occurred at a mean rate of 0.21 conflicts/hour within groups. Agonistic conflicts peaked during the birth season and occurred mostly in unknown or infant proximity contexts. Females won 96% of all decided agonistic conflicts (N = 154). Other outcomes occurred only when females were with infants during the birth season. In that context, one female sometimes withdrew from her pair partner, and another female withdrew or fled from an extra-group male whose attacks eventually led to infanticide. Our results suggest female dominance in pair-living L. edwardsi. We hypothesize that elevated female aggression may convey fitness benefits to female Lepilemur because it generally allows females to intervene quickly and efficiently on behalf of their infants against nonfather males who may approach the newborn infants when they are parked in vegetation.
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Affiliation(s)
- Solofonirina Rasoloharijaona
- Faculté des Sciences de Technologies et de l'Environnement, University of Mahajanga, Mahajanga, Madagascar
- Ecole Doctorale sur les Ecosystèmes Naturels, University of Mahajanga, Mahajanga, Madagascar
| | - Blanchard Randrianambinina
- Faculté des Sciences de Technologies et de l'Environnement, University of Mahajanga, Mahajanga, Madagascar
- Ecole Doctorale sur les Ecosystèmes Naturels, University of Mahajanga, Mahajanga, Madagascar
| | - Ute Radespiel
- Institute of Zoology, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
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2
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Correa LA, Aspillaga-Cid A, Bauer CM, Silva-Álvarez D, León C, Ramírez-Estrada J, Soto-Gamboa M, Hayes LD, Ebensperger LA. Social environment and anogenital distance length phenotype interact to explain testosterone levels in a communally rearing rodent: Part 1: The male side. Horm Behav 2024; 160:105479. [PMID: 38278060 DOI: 10.1016/j.yhbeh.2024.105479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/28/2024]
Abstract
In vertebrates, male testosterone levels vary across the year being generally higher during the mating season relative to the offspring rearing season. However, male testosterone levels may also be associated with male anogenital distance (AGD) length (a proxy of prenatal androgen exposition), and influenced by the social group environment. In social species, it has been proposed that high levels of testosterone could be incompatible with the development of an amicable social environment. Thus, in these species, it is predicted that males have relatively low levels of testosterone. Our goal was to examine the potential association between male serum testosterone levels, season, male AGD length, and the social environment in the rodent Octodon degus under natural conditions. We quantified male serum testosterone levels during the mating and offspring rearing seasons, and we determined the number of females and males in each social group, as well as the composition of groups, in terms of the AGD length of the female and male group mates, from 2009 to 2019. Our results revealed that male testosterone levels covary with season, being highest during the offspring rearing season. Additionally, male testosterone levels vary with male AGD length, and female and male social group environments. More importantly, male degus exhibit low levels of testosterone that are indistinguishable from female levels during offspring rearing season. Similar to other highly social mammals, where males and females live together year-round, male amicable behavior could be the best male mating strategy, thus leading to a reduction in circulating testosterone levels.
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Affiliation(s)
- Loreto A Correa
- Escuela de Medicina Veterinaria, Facultad de Medicina y Ciencias de la Salud, Universidad Mayor, Camino la Pirámide 5750, Huechuraba, Santiago, Chile.
| | - Antonia Aspillaga-Cid
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carolyn M Bauer
- Department of Biology, Swarthmore College, Swarthmore, PA, USA
| | - Danna Silva-Álvarez
- Escuela de Medicina Veterinaria, Facultad de Medicina y Ciencias de la Salud, Universidad Mayor, Camino la Pirámide 5750, Huechuraba, Santiago, Chile
| | - Cecilia León
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Ramírez-Estrada
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mauricio Soto-Gamboa
- Laboratorio de Ecología Conductual y Conservación, Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Loren D Hayes
- Department of Biology, Geology and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Luis A Ebensperger
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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3
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Correa LA, Aspillaga-Cid A, León C, Bauer CM, Ramírez-Estrada J, Hayes LD, Soto-Gamboa M, Ebensperger LA. Social environment and anogenital distance length phenotype interact to explain testosterone levels in a communally rearing rodent: Part 2: The female side. Horm Behav 2024; 160:105486. [PMID: 38295731 DOI: 10.1016/j.yhbeh.2024.105486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 03/26/2024]
Abstract
Testosterone is known as a "male" hormone; however, females also synthetize testosterone, which influences female sexual and aggressive behavior. In female vertebrates, as in males, testosterone levels can vary seasonally. However, female testosterone levels may also be related with female anogenital distance (AGD) length phenotype (a proxy of prenatal androgen exposure), and the social group environment. We used data from a long-term rodent study (2009-2019) in a natural population of degus (Octodon degus) to examine the potential associations between female serum testosterone levels, season, female AGD phenotype, and social group composition. We quantified female serum testosterone levels during the mating and offspring rearing seasons, and we determined the number of females and males in social groups, as well the composition of groups, in terms of the AGD of the female and male group mates. Our results indicate that female testosterone levels vary with season, being highest during the offspring rearing season. Additionally, female testosterone levels were associated with the number of male group-members and the AGD of male group-members but were not associated with female social environment and focal female AGD phenotype. Together, our results suggest that female testosterone levels are sensitive to intersexual interactions. Our results also reveal that female and male testosterone levels do not differ between the sexes, a finding previously reported only in rock hyraxes. We discuss how the complex social system of degus could be driving this physiological similarity between the sexes.
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Affiliation(s)
- Loreto A Correa
- Escuela de Medicina Veterinaria, Facultad de Medicina y Ciencias de la Salud, Universidad Mayor, Camino la Pirámide 5750, Huechuraba, Santiago, Chile.
| | - Antonia Aspillaga-Cid
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Cecilia León
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Carolyn M Bauer
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - Juan Ramírez-Estrada
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Loren D Hayes
- Department of Biology, Geology and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Mauricio Soto-Gamboa
- Laboratorio de Ecología Conductual y Conservación, Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Luis A Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
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4
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Mbiydzenyuy NE, Joanna Hemmings SM, Shabangu TW, Qulu-Appiah L. Exploring the influence of stress on aggressive behavior and sexual function: Role of neuromodulator pathways and epigenetics. Heliyon 2024; 10:e27501. [PMID: 38486749 PMCID: PMC10937706 DOI: 10.1016/j.heliyon.2024.e27501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 02/29/2024] [Accepted: 02/29/2024] [Indexed: 03/17/2024] Open
Abstract
Stress is a complex and multifaceted phenomenon that can significantly influence both aggressive behavior and sexual function. This review explores the intricate relationship between stress, neuromodulator pathways, and epigenetics, shedding light on the various mechanisms that underlie these connections. While the role of stress in both aggression and sexual behavior is well-documented, the mechanisms through which it exerts its effects are multifarious and not yet fully understood. The review begins by delving into the potential influence of stress on the Hypothalamic-Pituitary-Adrenal (HPA) axis, glucocorticoids, and the neuromodulators involved in the stress response. The intricate interplay between these systems, which encompasses the regulation of stress hormones, is central to understanding how stress may contribute to aggressive behavior and sexual function. Several neuromodulator pathways are implicated in both stress and behavior regulation. We explore the roles of norepinephrine, serotonin, oxytocin, and androgens in mediating the effects of stress on aggression and sexual function. It is important to distinguish between general sexual behavior, sexual motivation, and the distinct category of "sexual aggression" as separate constructs, each necessitating specific examination. Additionally, epigenetic mechanisms emerge as crucial factors that link stress to changes in gene expression patterns and, subsequently, to behavior. We then discuss how epigenetic modifications can occur in response to stress exposure, altering the regulation of genes associated with stress, aggression, and sexual function. While numerous studies support the association between epigenetic changes and stress-induced behavior, more research is necessary to establish definitive links. Throughout this exploration, it becomes increasingly clear that the relationship between stress, neuromodulator pathways, and epigenetics is intricate and multifaceted. The review emphasizes the need for further research, particularly in the context of human studies, to provide clinical significance and to validate the existing findings from animal models. By better understanding how stress influences aggressive behavior and sexual function through neuromodulator pathways and epigenetic modifications, this research aims to contribute to the development of innovative protocols of precision medicine and more effective strategies for managing the consequences of stress on human behavior. This may also pave way for further research into risk factors and underlying mechanisms that may associate stress with sexual aggression which finds application not only in neuroscience, but also law, ethics, and the humanities in general.
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Affiliation(s)
- Ngala Elvis Mbiydzenyuy
- Basic Science Department, School of Medicine, Copperbelt University, P.O Box 71191, Ndola, Zambia
- Division of Medical Physiology, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
| | - Sian Megan Joanna Hemmings
- Division of Molecular Biology & Human Genetics, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
| | - Thando W. Shabangu
- Division of Medical Physiology, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
| | - Lihle Qulu-Appiah
- Division of Medical Physiology, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
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5
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Aspesi D, Bass N, Kavaliers M, Choleris E. The role of androgens and estrogens in social interactions and social cognition. Neuroscience 2023:S0306-4522(23)00151-3. [PMID: 37080448 DOI: 10.1016/j.neuroscience.2023.03.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 03/02/2023] [Accepted: 03/28/2023] [Indexed: 04/22/2023]
Abstract
Gonadal hormones are becoming increasingly recognized for their effects on cognition. Estrogens, in particular, have received attention for their effects on learning and memory that rely upon the functioning of various brain regions. However, the impacts of androgens on cognition are relatively under investigated. Testosterone, as well as estrogens, have been shown to play a role in the modulation of different aspects of social cognition. This review explores the impact of testosterone and other androgens on various facets of social cognition including social recognition, social learning, social approach/avoidance, and aggression. We highlight the relevance of considering not only the actions of the most commonly studied steroids (i.e., testosterone, 17β-estradiol, and dihydrotestosterone), but also that of their metabolites and precursors, which interact with a plethora of different receptors and signalling molecules, ultimately modulating behaviour. We point out that it is also essential to investigate the effects of androgens, their precursors and metabolites in females, as prior studies have mostly focused on males. Overall, a comprehensive analysis of the impact of steroids such as androgens on behaviour is fundamental for a full understanding of the neural mechanisms underlying social cognition, including that of humans.
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Affiliation(s)
- Dario Aspesi
- Department of Psychology and Neuroscience Program, University of Guelph
| | - Noah Bass
- Department of Psychology and Neuroscience Program, University of Guelph
| | - Martin Kavaliers
- Department of Psychology and Neuroscience Program, University of Guelph; Department of Psychology, University of Western Ontario, London, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, Canada
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph.
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6
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Jiménez R, Burgos M, Barrionuevo FJ. The Biology and Evolution of Fierce Females (Moles and Hyenas). Annu Rev Anim Biosci 2023; 11:141-162. [PMID: 36130099 DOI: 10.1146/annurev-animal-050622-043424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Talpid moles and spotted hyenas have become the paradigms of anatomical and behavioral female masculinization. Females of many mole species develop ovotestes that produce testosterone, show external genitalia that resemble that of males, and close their vaginal orifice after every estrus, and female spotted hyenas lack an external vaginal orifice and develop a pseudoscrotum and a large pseudopenis through which they urinate, mate, and give birth. We review current knowledge about several significant aspects of the biology and evolution of these females, including (a) their specific study methods; (b) their unique anatomical features, and how these peculiarities influence certain physiological functions; and (c) the role that steroid hormones as well as genetic and environmental factors may have in urogenital system development, aggressive behavior, and social dominance. Nevertheless, both mole and hyena females are exceptionally efficient mothers, so their peculiar genitalia should not call into question their femininity.
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Affiliation(s)
- Rafael Jiménez
- Department of Genetics, Institute of Biotechnology, and Center of Biomedical Research (CIBM), University of Granada, Armilla, Granada, Spain; , ,
| | - Miguel Burgos
- Department of Genetics, Institute of Biotechnology, and Center of Biomedical Research (CIBM), University of Granada, Armilla, Granada, Spain; , ,
| | - Francisco J Barrionuevo
- Department of Genetics, Institute of Biotechnology, and Center of Biomedical Research (CIBM), University of Granada, Armilla, Granada, Spain; , ,
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7
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Mustoe A. A tale of two hierarchies: Hormonal and behavioral factors underlying sex differences in social dominance in cooperative breeding callitrichids. Horm Behav 2023; 147:105293. [PMID: 36463691 DOI: 10.1016/j.yhbeh.2022.105293] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 12/02/2022]
Abstract
Callitrichid primates are recognized for high levels of sociality in small groups, their great behavioral flexibility, and single-female dominant hierarchies. Previous work has highlighted that dominant, breeding callitrichids engage in behavioral and hormonal reproductive suppression of related and unrelated subordinates by both producing more offspring, having higher levels of ovulatory hormones, and accessing more sociosexual opportunities. This suppression constitutes a nexus of changes in pituitary responsiveness, ovarian cyclicity, sexual behavior, affiliation, and aggression. In this review, I will highlight important features that characterize callitrichid social hierarchies across broad social contexts. Dominant females sometimes exert reproductive suppression on subordinate nonbreeding females, but this suppression varies across callitrichids based on social stability and changes in group composition, particularly related to the number, experience, and age of nonbreeding subordinates. Meanwhile, dominant males may induce suppression of reproduction in subordinate males, but these effects occur by different behavioral and endocrine mechanisms and to a much lesser extent than their female counterparts; While dominant female callitrichids usually show higher levels of aggression relative to their male counterparts, callitrichids show a general absence of intersexual dominance, likely as an effort of maintaining a cohesive breeding pair within a stable social group and social cooperation. Future efforts are needed to identify precise neuroendocrine mechanisms underlying the presence of sex differences in callitrichid behavior separate from peripheral reproductive function. This is especially important with regard to parental experience, social relationships, development and aging, with larger implications toward understanding sex differences in overall health and wellbeing.
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Affiliation(s)
- Aaryn Mustoe
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA.
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8
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Smit N, Ngoubangoye B, Charpentier MJE, Huchard E. Dynamics of intersexual dominance in a highly dimorphic primate. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.931226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Intersexual dominance, which is measured by the probability that members of one sex elicit submission of members of the other sex during agonistic interactions, is often skewed in favor of males. However, even in sexually dimorphic species, several factors may influence intersexual dominance. Here, we use an 8-year dataset to examine the dynamics of intersexual dominance in wild-living mandrills (Mandrillus sphinx). Mandrills exhibit an extreme male-biased sexual size dimorphism but females show pronounced kin-differentiated social relationships and occasionally form coalitions against males. We established intersexual hierarchies across consecutive 6-month time blocks, representing either mating or birth seasons. Although females appeared to outrank 11% of males, they elicited male submission in only 2% of agonistic interactions against males. This discrepancy is likely due to the temporary residency of most males in the exceptionally large mandrill groups, the sexually coercive male mating strategies and the scarce number of agonistic interactions within most dyads, that may limit hierarchical inferences. In a second step, we found that the intersexual hierarchy mixes the intrasexual ones respecting their respective order. Females outranked mostly young and old males during the mating (vs. birth) season and social integration was positively correlated to dominance status in both sexes. In a third step, we found that females win more conflicts against young or old males which are closer to them in the intersexual hierarchy. These results extend our understanding of female-male dominance relationships by indicating that female mandrills occasionally outrank males who are considerably larger than them, and that a combination of demographic and social factors can influence the intersexual hierarchy.
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9
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Survilienė V, Rukšėnas O, Pomeroy PP, Moss SEW, Bennett KA. Evaluating suitability of saliva to measure steroid concentrations in grey seal pups. Gen Comp Endocrinol 2022; 326:114070. [PMID: 35671833 DOI: 10.1016/j.ygcen.2022.114070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 05/04/2022] [Accepted: 06/02/2022] [Indexed: 11/28/2022]
Abstract
Measurement of steroids in wild pinnipeds can facilitate assessment of breeding, nutritional and stress status, and is useful in understanding behavioral responses. Even in young animals, sex steroids may be important in behavioral interactions and immune modulation. Use of saliva can avoid the large fluctuations seen in some steroids in plasma, and can negate the need for venipuncture, making it a potentially useful matrix in the wildlife. However, its utility in estimating steroid levels in wild young pinnipeds has not been evaluated. Here, we investigated the suitability of saliva for steroid hormone analysis in wild grey seal pups during their suckling and post-weaning fast periods. We collected saliva (n = 38) and plasma (n = 71) samples during the breeding season on the Isle of May, Scotland, 2012. We investigated success of sample collection, ease of preparation, accuracy and precision of analysis, and, where possible, comparability of measurements (n = 27) from saliva and plasma. Plasma sampling was rapid, whereas sampling saliva took up to five times longer. Analytical performance criteria (parallelism, accuracy, and precision (intra and inter assay co-efficient of variation (% CV)) of commercial ELISA kits to measure estradiol, testosterone and cortisol in both matrices were assessed. Estradiol and cortisol assays performed well and can be used in plasma and saliva. However, we could not confidently validate testosterone for either matrix. Saliva estradiol correlated with levels in plasma. Saliva sample preparation was faster and simpler than plasma preparation because it did not require extraction. However, given the additional time taken to obtain saliva in the wild, the possibility of blood contamination from oral damage and the lower success rate in obtaining sufficient sample for analysis, we recommend that this matrix only be used as an alternative to plasma sampling measurement in pinnipeds when animals are anaesthetized, tolerate mouth swabbing, or have been trained to accept saliva sampling in captivity.
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Affiliation(s)
- V Survilienė
- Institute of Biosciences, Life Sciences Centre, Vilnius University, Saulėtekio av. 7, LT-10257, Lithuania.
| | - O Rukšėnas
- Institute of Biosciences, Life Sciences Centre, Vilnius University, Saulėtekio av. 7, LT-10257, Lithuania
| | - P P Pomeroy
- Sea Mammal Research Unit (SMRU), Scottish Ocean Institute, East Sands, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - S E W Moss
- Sea Mammal Research Unit (SMRU), Scottish Ocean Institute, East Sands, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - K A Bennett
- School of Applied Sciences, Division of Health Sciences, Abertay University, Bell Street, Dundee DD1 1HG, UK
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10
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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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11
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Sonnweber R, Stevens JMG, Hohmann G, Deschner T, Behringer V. Plasma Testosterone and Androstenedione Levels Follow the Same Sex-Specific Patterns in the Two Pan Species. BIOLOGY 2022; 11:biology11091275. [PMID: 36138754 PMCID: PMC9495489 DOI: 10.3390/biology11091275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/27/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Generally male mammals are more aggressive than their female peers. In these males, aggressive behavior is linked to levels of androgens; higher levels of testosterone are predictive of higher aggression rates or more severe aggression. There are some species where the pattern of sex-specific aggression is reversed, and it was hypothesized that high levels of androgens may be responsible for social dominance and aggressiveness in these females. Studies so far found that females of species with sex-reversed aggression patterns (e.g., spotted hyenas and ring-tailed lemurs) had lower plasma testosterone levels than their male peers, but a precursor of testosterone, androstenedione, was comparable or even higher in females than in males. This supported the idea that selection for female aggressiveness may be facilitated through augmented androgen secretion. Here we show that in two sister species, bonobos and chimpanzees, that differ in terms of sex-specific aggression patterns, females have lower plasma testosterone levels and higher plasma androstenedione levels than their male peers. Thus, our data do not support a theory of a role of female androgen levels on the expression of sex-specific patterns of aggression. Abstract In most animals, males are considered more aggressive, in terms of frequency and intensity of aggressive behaviors, than their female peers. However, in several species this widespread male-biased aggression pattern is either extenuated, absent, or even sex-reversed. Studies investigating potential neuro-physiological mechanisms driving the selection for female aggression in these species have revealed an important, but not exclusive role of androgens in the expression of the observed sex-specific behavioral patterns. Two very closely related mammalian species that markedly differ in the expression and degree of sex-specific aggression are the two Pan species, where the chimpanzee societies are male-dominated while in bonobos sex-biased aggression patterns are alleviated. Using liquid chromatography–mass spectrometry (LC-MS) methods, we measured levels of plasma testosterone and androstenedione levels in male and female zoo-housed bonobos (N = 21; 12 females, 9 males) and chimpanzees (N = 41; 27 females, 14 males). Our results show comparable absolute and relative intersexual patterns of blood androgen levels in both species of Pan. Plasma testosterone levels were higher in males (bonobos: females: average 0.53 ± 0.30 ng/mL; males 6.70 ± 2.93 ng/mL; chimpanzees: females: average 0.40 ± 0.23 ng/mL; males 5.84 ± 3.63 ng/mL) and plasma androstenedione levels were higher in females of either species (bonobos: females: average 1.83 ± 0.87 ng/mL; males 1.13 ± 0.44 ng/mL; chimpanzees: females: average 1.84 ± 0.92 ng/mL; males 1.22 ± 0.55 ng/mL). The latter result speaks against a role of androstenedione in the mediation of heightened female aggression, as had been suggested based on studies in other mammal species where females are dominant and show high levels of female aggressiveness.
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Affiliation(s)
- Ruth Sonnweber
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
- Correspondence:
| | - Jeroen M. G. Stevens
- Behavioral Ecology and Ecophysiology, Department of Biology, University of Antwerp, Campus Drie Eiken, Building D, D1.21, Universiteitsplein 1, 2610 Antwerp, Belgium
| | - Gottfried Hohmann
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
- Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315 Radolfzell/Konstanz, Germany
| | - Tobias Deschner
- Comparative BioCognition, Institute of Cognitive Science, University of Osnabrück, Artilleriestrasse 34, 49090 Osnabrück, Germany
| | - Verena Behringer
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
- Endocrinology Laboratory, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany
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12
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Kappeler PM, Fichtel C, Radespiel U. The Island of Female Power? Intersexual Dominance Relationships in the Lemurs of Madagascar. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.858859] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The extant primates of Madagascar (Lemuriformes) represent the endpoints of an adaptive radiation following a single colonization event more than 50 million years ago. They have since evolved a diversity of life history traits, ecological adaptations and social systems that rivals that of all other living primates combined. Their social systems are characterized by a unique combination of traits, including the ability of adult females to dominate adult males. In fact, there is no other group of mammals in which female dominance is so widespread. Yet, recent research has indicated that there is more interspecific variation in lemur intersexual relationships than previously acknowledged. Here, we therefore review and summarize the relevant literature, quantifying the extent of sex-bias in intersexual dominance relations documented in observational and experimental studies in captivity and the wild. Female dominance is often, but not always, implemented by spontaneous male submission in the absence of female aggression and linked to female sexual maturation. We connect the available evidence to the hypotheses that have been proposed to explain the evolution of female dominance among lemurs. The occurrence of female dominance in all lemur families and the interspecific variation in its extent indicate that it has evolved soon after lemurs colonized Madagascar – presumably in response to particular ecological challenges – and that it has since been reduced in magnitude independently in some taxa. Our study contributes important comparative information on sex roles from an independent primate radiation and provides general insights into the conditions, opportunities and obstacles in the evolution of female-biased power.
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13
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Grebe NM, Sheikh A, Drea CM. Integrating the female masculinization and challenge hypotheses: Female dominance, male deference, and seasonal hormone fluctuations in adult blue-eyed black lemurs (Eulemur flavifrons). Horm Behav 2022; 139:105108. [PMID: 35033896 DOI: 10.1016/j.yhbeh.2022.105108] [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: 09/15/2021] [Revised: 12/22/2021] [Accepted: 01/03/2022] [Indexed: 11/19/2022]
Abstract
In the decades since female social dominance was first described in strepsirrhine primates, researchers have sought to uncover the proximate and ultimate explanations for its development. In the females of various female-dominant species, androgens have been implicated as regulators of behavior and/or predictors of seasonal fluctuations in aggression (the 'Female Masculinization Hypothesis'). Males, more generally, respond to changing social demands via seasonal fluctuations in androgen-mediated behavior (the 'Challenge Hypothesis'), that may also entail changes in activation of the hypothalamic-pituitary-adrenal axis. Here, we explore if androgens, glucocorticoids, and intersexual behavior fluctuate seasonally in the female-dominant, blue-eyed black lemur (Eulemur flavifrons), with potential consequences for understanding female aggression and male deference. Across two studies conducted during the breeding and nonbreeding seasons, we assessed rates of mixed-sex, dyadic social behavior (aggression and affiliation) and concentrations of fecal glucocorticoid metabolites (Study 1) and serum sex hormones (androstenedione, testosterone, and estradiol; Study 2). Our results align with several predictions inspired by the Female Masculinization and Challenge Hypotheses for intersexual relations: During the breeding season, specifically, both aggression and androstenedione peaked in females, while female-initiated affiliation decreased, potentially to facilitate female resource access and reproductive control. By comparison, all target hormones (androgens, estrogen, and glucocorticoids) peaked in males, with glucocorticoid concentrations potentially increasing in response to the surge in female aggression, and unusually high estrogen concentrations year-round potentially facilitating male deference via male-initiated affiliation. These results suggest complex, seasonally and hormonally mediated behavior in Eulemur flavifrons.
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Affiliation(s)
- Nicholas M Grebe
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, United States of America.
| | - Alizeh Sheikh
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, United States of America
| | - Christine M Drea
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, United States of America; Department of Biology, Duke University, Durham, NC 27708, United States of America
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14
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Oliveira VEDM, Bakker J. Neuroendocrine regulation of female aggression. Front Endocrinol (Lausanne) 2022; 13:957114. [PMID: 36034455 PMCID: PMC9399833 DOI: 10.3389/fendo.2022.957114] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
Classically the neurobiology of aggression has been studied exclusively in males. Thus, females have been considered mildly aggressive except during lactation. Interestingly, recent studies in rodents and humans have revealed that non-lactating females can show exacerbated and pathological aggression similarly to males. This review provides an overview of recent findings on the neuroendocrine mechanisms regulating aggressive behavior in females. In particular, the focus will be on novel rodent models of exaggerated aggression established in non-lactating females. Among the neuromodulatory systems influencing female aggression, special attention has been given to sex-steroids and sex-steroid-sensitive neuronal populations (i.e., the core nuclei of the neural pathway of aggression) as well as to the neuropeptides oxytocin and vasopressin which are major players in the regulation of social behaviors.
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15
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Alrabadi N, Al-Rabadi GJ, Maraqa R, Sarayrah H, Alzoubi KH, Alqudah M, Al-U'datt DG. Androgen effect on body weight and behaviour of male and female rats: novel insight on the clinical value. Andrologia 2020; 52:e13730. [PMID: 32629528 DOI: 10.1111/and.13730] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/18/2020] [Accepted: 06/03/2020] [Indexed: 01/15/2023] Open
Abstract
Androgenic-anabolic steroids (AASs) are synthetic derivative forms of the hormone testosterone. Sustanon® 250 solution for injection is one of those AASs that is used for low hormone levels and is self-administered for recreational purposes. This study was conducted to investigate the effects of sustanon on the body weight of male and female rats. Animals were injected different doses of sustanon (vehicle, 1, 3.2, 10, 32 and 100 mg/kg, I.M., once/week, for 6 weeks), and the weights for each animal were obtained. The rats were observed for agitated/aggressive behaviours every other day. In the present study, sustanon injections at 1, 3.2, 10, 32 and 100 mg/kg treatments did not alter body weight in male rats compared to the control group. However, moderately high and supraphysiological doses of sustanon (3.2, 10 and 32 mg/kg) resulted in a significant increase in body weight after 1 month of weekly treatment in female rats. Aggressive/agitated behaviours were observed only in female rats at the period of weight increase. In conclusion, different doses of sustanon did not alter the body weight in male rats after 6 weeks of treatment but doses of 3.2, 10 and 32 mg/kg resulted in a significant increase in body weight of female rats.
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Affiliation(s)
- Nasr Alrabadi
- Department of Pharmacology, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Ghaid J Al-Rabadi
- Department of Animal Production, Faculty of Agriculture, Mutah University, Al-Karak, Jordan
| | - Rasha Maraqa
- Department of Pharmacology, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Haneen Sarayrah
- Department of Pharmacology, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Karem H Alzoubi
- Department of Clinical Pharmacy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan
| | - Mohammad Alqudah
- Department of Physiology, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Doa'a G Al-U'datt
- Department of Physiology, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
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16
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Rosvall KA, Bentz AB, George EM. How research on female vertebrates contributes to an expanded challenge hypothesis. Horm Behav 2020; 123:104565. [PMID: 31419407 PMCID: PMC7061077 DOI: 10.1016/j.yhbeh.2019.104565] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 12/21/2022]
Abstract
The bi-directional links between hormones and behavior have been a rich area of research for decades. Theory on the evolution of testosterone (T) was greatly advanced by the challenge hypothesis, which presented a framework for understanding interspecific, seasonal, and social variation in T levels in males, and how they are shaped by the competing demands of parental care and male-male competition. Female competition is also widespread in nature, although it is less clear whether or how the challenge hypothesis applies to females. Here, we evaluate this issue in four parts: (1) We summarize and update prior analyses of seasonal plasticity and interspecific variation in T in females. (2) We evaluate experimental links between T and female aggression on shorter timescales, asking how T manipulations affect aggression and conversely, how social manipulations affect T levels in female mammals, birds, lizards, and fishes. (3) We examine alternative mechanisms that may link aggression to the social environment independently of T levels in circulation. (4) We present a case study, including new data analyses, in an aggressive female bird (the tree swallow, Tachycineta bicolor) to explore how variation in tissue-level processing of T may bridge the gap between circulating T and variation in behavior that is visible to natural selection. We close by connecting these multivariate levels of sex steroid signaling systems alongside different temporal scales (social, seasonal, and evolutionary) to generate broadly applicable insights into how animals respond to their social environment, regardless of whether they are male or female.
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Affiliation(s)
- Kimberly 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.
| | - Alexandra 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
| | - Elizabeth 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
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17
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Reese M, Bryant D, Ethridge L. Biomarkers for moral cognition: Current status and future prospects for neurotransmitters and neuropeptides. Neurosci Biobehav Rev 2020; 113:88-97. [PMID: 32171842 DOI: 10.1016/j.neubiorev.2020.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 01/24/2020] [Accepted: 03/08/2020] [Indexed: 10/24/2022]
Abstract
The translational neuroscience of moral cognitions draws together developments throughout the fields of neuroscience pertaining to moral cognitions in order to better the human condition. That condition, seen through this lens, is one in which much of the violence and suffering we endure and inflict upon one another is based on moral cognitions-attitudes, beliefs, judgments-that are thought to result from correct or incorrect perceptions of moral properties. The biology tells a different story; namely, that moral cognitions, like other cognitions and mental states, are predicted and determined by biological mechanisms modulated by genotype, neurotransmitter availability and receptor density, neurophysiology, and individual differences among these as well as biology-environment interactions including nutrition, experience, and microbiome. A wealth of research has demonstrated that moral reasoning and judgments are easily alterable with the application of pharmaceuticals including SSRIs, and simpler treatments and conditions like the amount of time since one's last meal. Public health experts have pushed for analysis of violence and development of interventions treating violence as a public health pandemic. We see this research as a response to that call. Work in this field demonstrates that we are unaware of both the sources and nature of the cognitions on which we base much of our violent behaviors, societally and individually. Animal studies bolster the human subjects research, demonstrating the evolutionary roots of the causal mechanisms beneath our social structures and group formations.
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Affiliation(s)
- Melody Reese
- Dept of Psychology, University of Oklahoma, United States
| | - Douglas Bryant
- Dept of Psychology, University of Oklahoma, United States
| | - Lauren Ethridge
- Dept of Psychology, University of Oklahoma, United States; Dept of Pediatrics, University of Oklahoma Health Sciences Center, United States.
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18
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Grebe NM, Fitzpatrick C, Sharrock K, Starling A, Drea CM. Organizational and activational androgens, lemur social play, and the ontogeny of female dominance. Horm Behav 2019; 115:104554. [PMID: 31276664 DOI: 10.1016/j.yhbeh.2019.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/06/2019] [Accepted: 07/01/2019] [Indexed: 11/18/2022]
Abstract
The role of androgens in shaping "masculine" traits in males is a core focus in behavioral endocrinology, but relatively little is known about an androgenic role in female aggression and social dominance. In mammalian models of female dominance, including the ring-tailed lemur (Lemur catta), links to androgens in adulthood are variable. We studied the development of ring-tailed lemurs to address the behavioral basis and ontogenetic mechanisms of female dominance. We measured behavior and serum androgen concentrations in 24 lemurs (8 males, 16 females) from infancy to early adulthood, and assessed their 'prenatal' androgen milieu using serum samples obtained from their mothers during gestation. Because logistical constraints limited the frequency of infant blood sampling, we accounted for asynchrony between behavioral and postnatal hormone measurements via imputation procedures. Imputation was unnecessary for prenatal hormone measurements. The typical sex difference in androgen concentrations in young lemurs was consistent with adult conspecifics and most other mammals; however, we found no significant sex differences in rough-and-tumble play. Female (but not male) aggression increased beginning at approximately 15 months, coincident with female puberty. In our analyses relating sexually differentiated behavior to androgens, we found no relationship with activational hormones, but several significant relationships with organizational hormones. Notably, associations of prenatal androstenedione and testosterone with behavior were differentiated, both by offspring sex and by type of behavior within offspring sexes. We discuss the importance of considering (1) missing data in behavioral endocrinology research, and (2) organizational androgens other than testosterone in studies of female dominance.
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Affiliation(s)
- Nicholas M Grebe
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA.
| | | | - Katherine Sharrock
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Anne Starling
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Christine M Drea
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA; Department of Biology, Duke University, Durham, NC, USA; University Program in Ecology, Duke University, Durham, NC, USA
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19
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McCoy DE, Frye BM, Kotler J, Embury A, Burkart JM, Burns M, Eyre S, Galbusera P, Hooper J, Idoe A, Goya AL, Mickelberg J, Quesada MP, Stevenson M, Sullivan S, Warneke M, Wojciechowski S, Wormell D, Haig D, Tardif SD. A comparative study of litter size and sex composition in a large dataset of callitrichine monkeys. Am J Primatol 2019; 81:e23038. [PMID: 31389057 PMCID: PMC6949018 DOI: 10.1002/ajp.23038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 11/11/2022]
Abstract
In many birds and mammals, the size and sex composition of litters can have important downstream effects for individual offspring. Primates are model organisms for questions of cooperation and conflict, but the factors shaping interactions among same-age siblings have been less-studied in primates because most species bear single young. However, callitrichines (marmosets, tamarins, and lion tamarins) frequently bear litters of two or more, thereby providing the opportunity to ask whether variation in the size and sex composition of litters affects development, survival, and reproduction. To investigate these questions, we compiled a large dataset of nine species of callitrichines (n = 27,080 individuals; Callithrix geoffroyi, Callithrix jacchus, Cebuella pygmaea, Saguinus imperator, Saguinus oedipus, Leontopithecus chrysomelas, Leontopithecus chrysopygus, Leontopithecus rosalia, and Callimico goeldii) from zoo and laboratory populations spanning 80 years (1938-2018). Through this comparative approach, we found several lines of evidence that litter size and sex composition may impact fitness. Singletons have higher survivorship than litter-born peers and they significantly outperform litter-born individuals on two measures of reproductive performance. Further, for some species, individuals born in a mixed-sex litter outperform isosexually-born individuals (i.e., those born in all-male or all-female litters), suggesting that same-sex competition may limit reproductive performance. We also document several interesting demographic trends. All but one species (C. pygmaea) has a male-biased birth sex ratio with higher survivorship from birth to sexual maturity among females (although this was significant in only two species). Isosexual litters occurred at the expected frequency (with one exception: C. pygmaea), unlike other animals, where isosexual litters are typically overrepresented. Taken together, our results indicate a modest negative effect of same-age sibling competition on reproductive output in captive callitrichines. This study also serves to illustrate the value of zoo and laboratory records for biological inquiry.
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Affiliation(s)
- Dakota E. McCoy
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Brett M. Frye
- Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634, USA
| | - Jennifer Kotler
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Psychology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Amanda Embury
- Department of Wildlife Conservation and Science, Zoos Victoria, Parkville, Victoria 3052, Australia
| | - Judith M. Burkart
- Department of Anthropology, University of Zurich, 8057 Zürich, Switzerland
| | - Monika Burns
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Simon Eyre
- Wellington Zoo, Newtown, Wellington 6021, New Zealand
| | - Peter Galbusera
- Royal Zoological Society of Antwerp (RZSA), Antwerp, Belgium
| | - Jacqui Hooper
- Wellington Zoo, Newtown, Wellington 6021, New Zealand
| | - Arun Idoe
- Apenheul Primate Park, Apeldoorn, The Netherlands
| | | | | | | | | | - Sara Sullivan
- Chicago Zoological Society, Brookfield, IL 60513, USA
| | - Mark Warneke
- Chicago Zoological Society, Brookfield, IL 60513, USA
| | | | - Dominic Wormell
- Durrell Wildlife Conservation Trust, Jersey, Channel Islands, UK
| | - David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Suzette D. Tardif
- Southwest National Primate Research Center, San Antonio, Texas 78245, USA
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20
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Abstract
Sex-biased power structures are common in human and nonhuman primate societies. “Female dominance” is a term applied to a wide range of female-biased power structures. However, the full extent of this variation remains obscure because an adequate vocabulary of power has not been adopted consistently. Female power occurs throughout primates and other animals, even in male-dominant societies, but the legacy of patriarchy persists in primatologists’ use of language and implicit assumptions about intersexual power. While explanations for the occurrence of female power can be accommodated within existing ethological theory, many hypotheses seeking to explain the evolution of female power are narrowly focused on particular taxa. Theories about primate social evolution would benefit from a synthesis of the disparate literature on power, increased emphasis on intersexual social relationships, and comparative studies that include the full behavioral diversity of primates and other mammals.
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Affiliation(s)
- Rebecca J. Lewis
- Department of Anthropology, University of Texas at Austin, Austin, Texas 78712, USA
- Ankoatsifaka Research Station, Kirindy Mitea National Park, Morondava 619, Madagascar
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21
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Li CY, Huang SP, Garcia M, Fuller A, Hsu Y, Earley RL. Sexual phenotype drives variation in endocrine responses to social challenge in a quasi-clonal animal. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180002. [PMID: 29765691 PMCID: PMC5936956 DOI: 10.1098/rsos.180002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 02/26/2018] [Indexed: 06/08/2023]
Abstract
In many species, males tend to behave more aggressively than females and female aggression often occurs during particular life stages such as maternal defence of offspring. Though many studies have revealed differences in aggression between the sexes, few studies have compared the sexes in terms of their neuroendocrine responses to contest experience. We investigated sex differences in the endocrine response to social challenge using mangrove rivulus fish, Kryptolebias marmoratus. In this species, sex is determined environmentally, allowing us to produce males and hermaphrodites with identical genotypes. We hypothesized that males would show elevated androgen levels (testosterone and 11-ketotestosterone) following social challenge but that hermaphrodite responses might be constrained by having to maintain both testicular and ovarian tissue. To test this hypothesis, we staged fights between males and between hermaphrodites, and then compared contest behaviour and hormone responses between the sexes. Hermaphrodites had significantly higher oestradiol but lower 11-ketotestosterone than males before contests. Males took longer to initiate contests but tended to fight more aggressively and sustain longer fights than hermaphrodites. Males showed a dramatic post-fight increase in 11-ketotestosterone but hermaphrodites did not. Thus, despite being genetically identical, males and hermaphrodites exhibit dramatically different fighting strategies and endocrine responses to contests.
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Affiliation(s)
- Cheng-Yu Li
- Department of Biological Sciences, University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA
| | - Shu-Ping Huang
- Department of Life Science, National Taiwan Normal University, No. 88, Section 4, Tingchou Rd, Taipei 116, Taiwan, Republic of China
| | - Mark Garcia
- Department of Biological Sciences, University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA
| | - Adam Fuller
- Department of Biological Sciences, University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA
| | - Yuying Hsu
- Department of Life Science, National Taiwan Normal University, No. 88, Section 4, Tingchou Rd, Taipei 116, Taiwan, Republic of China
| | - Ryan L. Earley
- Department of Biological Sciences, University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA
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22
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Kelly AM, Saunders AG, Ophir AG. Mechanistic substrates of a life history transition in male prairie voles: Developmental plasticity in affiliation and aggression corresponds to nonapeptide neuronal function. Horm Behav 2018; 99:14-24. [PMID: 29407458 PMCID: PMC5880752 DOI: 10.1016/j.yhbeh.2018.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/12/2018] [Accepted: 01/23/2018] [Indexed: 11/17/2022]
Abstract
Although prairie vole (Microtus ochrogaster) social behavior is well-characterized in adults, surprisingly little is known about the development of social behavior in voles. Further, the overwhelming majority of studies in prairie voles examine social behavior in a reproductive context. Here, we examine developmental plasticity in affiliation and aggression and their underlying neural correlates. Using sexually naïve males, we characterized interactions with an age-matched, novel, same-sex conspecific in four different age groups that span pre-weaning to adulthood. We found that prosocial behavior decreased and aggression increased as males matured. Additionally, pre-weaning males were more prosocial than nonsocial, whereas post-weaning males were more nonsocial than prosocial. We also examined nonapeptide neural activity in response to a novel conspecific in brain regions important for promoting sociality and aggression using the immediate early gene cFos. Assessment of developmental changes in neural activity showed that vasopressin neurons in the medial bed nucleus of the stria terminalis exhibit functional plasticity, providing a potential functional mechanism that contributes to this change in sociality as prairie voles mature. This behavioral shift corresponds to the transition from a period of allopatric cohabitation with siblings to a period of time when voles disperse and presumably attempt to establish and defend territories. Taken together our data provide a putative mechanism by which brain and behavior prepare for the opportunity to pairbond (characterized by selective affiliation with a partner and aggression toward unfamiliar conspecifics) by undergoing changes away from general affiliation and toward selective aggression, accounting for this important life history event.
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Affiliation(s)
- Aubrey M Kelly
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA.
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23
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Krieg CA, Getty T. Female house wrens value the nest cavity more than exclusive access to males during conflicts with female intruders. BEHAVIOUR 2018. [DOI: 10.1163/1568539x-00003481] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Individuals should fight hardest when they stand to lose the most. Whereas males frequently compete for fertile females, females more often compete for high quality males, male care, or resources required to breed. We asked whether established, territorial female house wrens (Troglodytes aedon) challenged by simulated female intruders fight as if they place more value on retaining (1) their nesting cavity or (2) exclusive access to other benefits offered by males. We randomly assigned house wren pairs to receive one or three nest boxes and then assayed female aggression. The relative costs to losing differed between box treatments. For one-box females, the risk of losing the cavity and territory was higher. For three-box females, the risk of losing the cavity may be lower because intruders may be able to settle as secondary females in the supplemental boxes. In this situation, females would lose exclusive access to males and their territories but would still retain the male’s assistance rearing offspring since male house wrens favour their oldest brood. We found that one-box females were significantly more aggressive. This response may be adaptive, as females that switched territories between broods were significantly more likely to lose their entire nest prior to hatching than females that retained the same territory. We interpret our results to mean that female house wrens value the nest cavity more than other benefits from exclusive access to males and their territories. This work contributes to a body of evidence that females often compete for resources required to breed.
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Affiliation(s)
- Cara A. Krieg
- aMichigan State University, Department of Integrative Biology, East Lansing, MI 48824, USA
- bW.K. Kellogg Biological Station, Hickory Corners, MI 49060, USA
| | - Thomas Getty
- aMichigan State University, Department of Integrative Biology, East Lansing, MI 48824, USA
- bW.K. Kellogg Biological Station, Hickory Corners, MI 49060, USA
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24
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Becker EA, Castelli FR, Yohn CN, Spencer L, Marler CA. Species differences in urine scent-marking and counter-marking in Peromyscus. Behav Processes 2017; 146:1-9. [PMID: 29100968 DOI: 10.1016/j.beproc.2017.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/30/2017] [Accepted: 10/30/2017] [Indexed: 10/18/2022]
Abstract
Species comparisons indicate that scent-marking may differ as a function of mating system and co-housing with the opposite sex ("pairing"). We previously demonstrated that pairing may decrease male solicitation to unfamiliar females in the monogamous Peromyscus californicus but not in the non-monogamous P. leucopus. Whether urine scent-marking of females changes following pairing and whether scent-marking of paired males varies in response to scent-marks of their cagemate versus those of an unfamiliar female has not been examined. Therefore, we tested P. californicus and P. leucopus for within and between species differences in urine scent-marking of: 1) paired and non-paired females in an unscented arena, and 2) paired males in response to their female cagemate's or an unfamiliar female's scent-marks (counter-marking). Consistent with previous findings, P. californicus of both sexes deposited more urine scent-marks and covered greater surface area than P. leucopus. In both species, female scent-marking did not differ according to pairing status and male counter-marking did not differ in response to the scent-marks of their female cagemate versus an unfamiliar female. More females of both species and more P. leucopus, but not P. californicus, males scent-marked more around the perimeter than centrally. Potential explanations for these findings are discussed.
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Affiliation(s)
- Elizabeth A Becker
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States; Department of Psychology, Saint Joseph's University 5600 City Ave., Philadelphia, PA 19131, United States.
| | - Frank R Castelli
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States
| | - Christine N Yohn
- Department of Psychology, Saint Joseph's University 5600 City Ave., Philadelphia, PA 19131, United States
| | - Lindsey Spencer
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States
| | - Catherine A Marler
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States; Department of Zoology, University of Wisconsin-Madison, 250 N Mills St., Madison, WI 53706, United States
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25
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Kappeler PM. Sex roles and adult sex ratios: insights from mammalian biology and consequences for primate behaviour. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160321. [PMID: 28760762 PMCID: PMC5540861 DOI: 10.1098/rstb.2016.0321] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2017] [Indexed: 12/23/2022] Open
Abstract
Theoretical models and empirical studies in various taxa have identified important links between variation in sex roles and the number of adult males and females (adult sex ratio (ASR)) in a population. In this review, I examine these relationships in non-human primates. Because most existing theoretical models of the evolution of sex roles focus on the evolutionary origins of sex-biased behaviour, they offer only a general scaffold for predicting variation in sex roles among and within species. I argue that studies examining sex role variation at these more specific levels need to take social organization into account to identify meaningful levels for the measurement of ASR and to account for the fact that ASR and sex roles mutually influence each other. Moreover, taxon-specific life-history traits can constrain sex role flexibility and impact the operational sex ratio (OSR) by specifying the minimum length of female time outs from reproduction. Using examples from the primate literature, I highlight practical problems in estimating ASR and OSR. I then argue that interspecific variation in the occurrence of indirect forms of paternal care might indeed be linked to variation in ASR. Some studies also indicate that female aggression and bonding, as well as components of inter-sexual relationships, are sensitive to variation in ASR. Thus, links between primate sex roles and sex ratios merit further study, and such studies could prompt the development of more specific theoretical models that make realistic assumptions about taxon-specific life history and social organization.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.
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Affiliation(s)
- Peter M Kappeler
- Wissenschaftskolleg zu Berlin, Wallotstrasse 19, 14193 Berlin, Germany
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
- Department of Sociobiology/Anthropology, University of Göttingen, Kellnerweg 6, 37077 Göttingen, Germany
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26
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Female dominance in two basal primates, Microcebus murinus and Microcebus lehilahytsara: variation and determinants. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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27
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Davies CS, Smyth KN, Greene LK, Walsh DA, Mitchell J, Clutton-Brock T, Drea CM. Exceptional endocrine profiles characterise the meerkat: sex, status, and reproductive patterns. Sci Rep 2016; 6:35492. [PMID: 27752129 PMCID: PMC5067592 DOI: 10.1038/srep35492] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 09/30/2016] [Indexed: 11/17/2022] Open
Abstract
In vertebrates, reproductive endocrine concentrations are strongly differentiated by sex, with androgen biases typifying males and estrogen biases typifying females. These sex differences can be reduced in female-dominant species; however, even the most masculinised of females have less testosterone (T) than do conspecific males. To test if aggressively dominant, female meerkats (Suricata suricatta) may be hormonally masculinised, we measured serum androstenedione (A4), T and estradiol (E2) in both sexes and social classes, during both ‘baseline’ and reproductive events. Relative to resident males, dominant females had greater A4, equivalent T and greater E2 concentrations. Males, whose endocrine values did not vary by social status, experienced increased T during reproductive forays, linking T to sexual behaviour, but not social status. Moreover, substantial E2 concentrations in male meerkats may facilitate their role as helpers. In females, dominance status and pregnancy magnified the unusual concentrations of measured sex steroids. Lastly, faecal androgen metabolites replicated the findings derived from serum, highlighting the female bias in total androgens. Female meerkats are thus strongly hormonally masculinised, possibly via A4’s bioavailability for conversion to T. These raised androgen concentrations may explain female aggressiveness in this species and give dominant breeders a heritable mechanism for their daughters’ competitive edge.
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Affiliation(s)
- Charli S Davies
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa.,Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Kendra N Smyth
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa.,Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA.,University Program in Ecology, Duke University, Durham, NC 27708, USA
| | - Lydia K Greene
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa.,Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA.,University Program in Ecology, Duke University, Durham, NC 27708, USA
| | - Debbie A Walsh
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa.,Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Jessica Mitchell
- Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa.,Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - 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, NC 27708, USA.,University Program in Ecology, Duke University, Durham, NC 27708, USA.,Department of Biology, Duke University, Durham, USA
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PAVLIČEV MIHAELA, WAGNER GÜNTER. The Evolutionary Origin of Female Orgasm. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 326:326-337. [DOI: 10.1002/jez.b.22690] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 06/20/2016] [Accepted: 06/23/2016] [Indexed: 01/23/2023]
Affiliation(s)
- MIHAELA PAVLIČEV
- Center for Prevention of Preterm Birth; Perinatal Institute, Cincinnati Children's Hospital Medical Center; Cincinnati Ohio
- Department of Pediatrics; University of Cincinnati College of Medicine; Cincinnati Ohio
| | - GÜNTER WAGNER
- Department of Ecology and Evolutionary Biology; Yale University; New Haven Connecticut
- Yale Systems Biology Institute; Yale University; West Haven Connecticut
- Department of Obstetrics, Gynecology and Reproductive Sciences; Yale Medical School; New Haven Connecticut
- Department of Obstetrics and Gynecology; Wayne State University; Detroit Michigan
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Bradley BJ, Snowdon CT, McGrew WC, Lawler RR, Guevara EE, McIntosh A, O'Connor T. Non-human primates avoid the detrimental effects of prenatal androgen exposure in mixed-sex litters: combined demographic, behavioral, and genetic analyses. Am J Primatol 2016; 78:1304-1315. [PMID: 27434275 DOI: 10.1002/ajp.22583] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/21/2016] [Accepted: 06/23/2016] [Indexed: 11/10/2022]
Abstract
Producing single versus multiple births has important life history trade-offs, including the potential benefits and risks of sharing a common in utero environment. Sex hormones can diffuse through amniotic fluid and fetal membranes, and females with male littermates risk exposure to high levels of fetal testosterone, which are shown to have masculinizing effects and negative fitness consequences in many mammals. Whereas most primates give birth to single offspring, several New World monkey and strepsirrhine species regularly give birth to small litters. We examined whether neonatal testosterone exposure might be detrimental to females in mixed-sex litters by compiling data from long-term breeding records for seven primate species (Saguinus oedipus; Varecia variegata, Varecia rubra, Microcebus murinis, Mirza coquereli, Cheirogaleus medius, Galago moholi). Litter sex ratios did not differ from the expected 1:2:1 (MM:MF:FF for twins) and 1:2:2:1 (MMM:MMF:MFF:FFF for triplets). Measures of reproductive success, including female survivorship, offspring-survivorship, and inter-birth interval, did not differ between females born in mixed-sex versus all-female litters, indicating that litter-producing non-human primates, unlike humans and rodents, show no signs of detrimental effects from androgen exposure in mixed sex litters. Although we found no evidence for CYP19A1 gene duplications-a hypothesized mechanism for coping with androgen exposure-aromatase protein evolution shows patterns of convergence among litter-producing taxa. That some primates have effectively found a way to circumvent a major cost of multiple births has implications for understanding variation in litter size and life history strategies across mammals.
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Affiliation(s)
- Brenda J Bradley
- Department of Anthropology, The George Washington University, Washington, District of Columbia. .,Department of Anthropology, Yale University, New Haven, Connecticut.
| | - Charles T Snowdon
- Department of Psychology, University of Wisconsin, Madison, Wisconsin
| | - William C McGrew
- Department of Archaeology & Anthropology, University of Cambridge, Cambridge, United Kingdom
| | - Richard R Lawler
- Department of Sociology and Anthropology, James Madison University, Harrisonburg, Virginia
| | - Elaine E Guevara
- Department of Anthropology, Yale University, New Haven, Connecticut
| | - Annick McIntosh
- Department of Anthropology, Yale University, New Haven, Connecticut
| | - Timothy O'Connor
- Institute for Genome Sciences and Program in Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, Maryland.,University of Maryland at College Park, College Park, Maryland
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30
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Kappeler PM, Fichtel C. Eco-evo-devo of the lemur syndrome: did adaptive behavioral plasticity get canalized in a large primate radiation? Front Zool 2015; 12 Suppl 1:S15. [PMID: 26816515 PMCID: PMC4722368 DOI: 10.1186/1742-9994-12-s1-s15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Comprehensive explanations of behavioral adaptations rarely invoke all levels famously admonished by Niko Tinbergen. The role of developmental processes and plasticity, in particular, has often been neglected. In this paper, we combine ecological, physiological and developmental perspectives in developing a hypothesis to account for the evolution of 'the lemur syndrome', a combination of reduced sexual dimorphism, even adult sex ratios, female dominance and mild genital masculinization characterizing group-living species in two families of Malagasy primates. RESULTS We review the different components of the lemur syndrome and compare it with similar adaptations reported for other mammals. We find support for the assertion that the lemur syndrome represents a unique set of integrated behavioral, demographic and morphological traits. We combine existing hypotheses about underlying adaptive function and proximate causation by adding a potential developmental mechanism linking maternal stress and filial masculinization, and outline an evolutionary scenario for its canalization. CONCLUSIONS We propose a new hypothesis linking ecological, physiological, developmental and evolutionary processes to adumbrate a comprehensive explanation for the evolution of the lemur syndrome, whose assumptions and predictions can guide diverse future research on lemurs. This hypothesis should also encourage students of other behavioral phenomena to consider the potential role of developmental plasticity in evolutionary innovation.
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Affiliation(s)
- Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Claudia Fichtel
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
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31
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Smyth KN, Drea CM. Patterns of parasitism in the cooperatively breeding meerkat: a cost of dominance for females. Behav Ecol 2015. [DOI: 10.1093/beheco/arv132] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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32
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Chary MC, Cruz JP, Bardi M, Becker EA. Paternal retrievals increase testosterone levels in both male and female California mouse (Peromyscus californicus) offspring. Horm Behav 2015; 73:23-9. [PMID: 26065732 DOI: 10.1016/j.yhbeh.2015.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 05/06/2015] [Accepted: 05/11/2015] [Indexed: 12/21/2022]
Abstract
The importance of maternal care on offspring development has received considerable attention, although more recently, researchers have begun to focus on the significance of paternal contributions. In the monogamous and bi-parental California mouse, fathers provide high levels of care, and therefore serve as a model system for studying paternal effects on behavior and underlying neuroendocrine mechanisms. Paternal retrievals in this species influence long term changes in brain (expression of arginine vasopressin-AVP) and behavior (aggression and parenting) in adult male offspring. Further, paternal retrievals induce a transient increase in testosterone (T) in male offspring, which is thought to mediate the relationship between paternal retrievals and AVP expression. Although the father-son relationship has been well characterized, few studies have examined father-daughter interactions. In California mice, paternal retrievals increase aggression in female offspring. Although T has been implicated in the regulation of female aggression, it remains unclear whether T may underlie long-term changes in female offspring aggression in response to paternal retrievals. In the current study, we examined the influence of paternal retrievals on T in both male and female offspring. Retrievals were manipulated experimentally by displacement of the pup and trunk blood was collected from retrieved, non-retrieved, and non-manipulated (baseline) pups. We found that fathers expressed similar levels of retrievals towards sons and daughters, and that T levels were elevated in retrieved, as compared to non-retrieved offspring. Similar to what has been previously described in male offspring and replicated here, female offspring that were retrieved had higher T levels than non-retrieved females. Neither females nor males experienced a change in corticosterone levels in response to retrievals suggesting offspring do not mount a stress response to paternal care. Therefore, our data suggest that paternal retrievals may serve similar functions in shaping adult behavior in both male and female offspring via modulation of hormone levels.
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Affiliation(s)
- Mamatha C Chary
- Department of Psychology, Saint Joseph's University, 5600 City Avenue, Philadelphia, PA 19131, USA; Department of Psychology, Virginia Polytechnic Institute and State University, 890 Drillfield Drive, Blacksburg, VA 24060, USA.
| | - Jayson P Cruz
- Department of Psychology, Saint Joseph's University, 5600 City Avenue, Philadelphia, PA 19131, USA
| | - Massimo Bardi
- Department of Psychology, Randolph-Macon College, 204 Henry Street, Ashland, VA 23005, USA
| | - Elizabeth A Becker
- Department of Psychology, Saint Joseph's University, 5600 City Avenue, Philadelphia, PA 19131, USA
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33
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Goymann W, Wingfield JC. Male-to-female testosterone ratios, dimorphism, and life history—what does it really tell us? Behav Ecol 2014. [DOI: 10.1093/beheco/aru019] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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34
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Stockley P, Campbell A. Female competition and aggression: interdisciplinary perspectives. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130073. [PMID: 24167303 PMCID: PMC3826202 DOI: 10.1098/rstb.2013.0073] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
This paper introduces a Theme Issue combining interdisciplinary perspectives in the study of female competition and aggression. Despite a history of being largely overlooked, evidence is now accumulating for the widespread evolutionary significance of female competition. Here, we provide a synthesis of contributions to this Theme Issue on humans and other vertebrates, and highlight directions for future research. Females compete for resources needed to survive and reproduce, and for preferred mates. Although female aggression takes diverse forms, under most circumstances relatively low-risk competitive strategies are favoured, most probably due to constraints of offspring production and care. In social species, dominance relationships and threats of punishment can resolve social conflict without resort to direct aggression, and coalitions or alliances may reduce risk of retaliation. Consistent with these trends, indirect aggression is a low cost but effective form of competition among young women. Costs are also minimized by flexibility in expression of competitive traits, with aggressive behaviour and competitive signalling tailored to social and ecological conditions. Future research on female competition and the proximate mediators of female aggression will be greatly enhanced by opportunities for interdisciplinary exchange, as evidenced by contributions to this Theme Issue.
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Affiliation(s)
- Paula Stockley
- Mammalian Behaviour and Evolution Group, Institute of Integrative Biology, University of Liverpool, Leahurst Campus, Chester High Road, Neston CH64 7TE, UK
| | - Anne Campbell
- Science Laboratories, Department of Psychology, Durham University, Durham DH1 3LE, UK
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