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Schacht R, Beissinger SR, Wedekind C, Jennions MD, Geffroy B, Liker A, Kappeler PM, Weissing FJ, Kramer KL, Hesketh T, Boissier J, Uggla C, Hollingshaus M, Székely T. Adult sex ratios: causes of variation and implications for animal and human societies. Commun Biol 2022; 5:1273. [PMID: 36402823 PMCID: PMC9675760 DOI: 10.1038/s42003-022-04223-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022] Open
Abstract
Converging lines of inquiry from across the social and biological sciences target the adult sex ratio (ASR; the proportion of males in the adult population) as a fundamental population-level determinant of behavior. The ASR, which indicates the relative number of potential mates to competitors in a population, frames the selective arena for competition, mate choice, and social interactions. Here we review a growing literature, focusing on methodological developments that sharpen knowledge of the demographic variables underlying ASR variation, experiments that enhance understanding of the consequences of ASR imbalance across societies, and phylogenetic analyses that provide novel insights into social evolution. We additionally highlight areas where research advances are expected to make accelerating contributions across the social sciences, evolutionary biology, and biodiversity conservation.
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Affiliation(s)
- Ryan Schacht
- Department of Anthropology, East Carolina University, Greenville, NC, USA.
| | - Steven R Beissinger
- Department of Environmental Science, Policy and Management and Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
| | - Claus Wedekind
- Department of Ecology and Evolution, University of Lausanne, 1015, Lausanne, Switzerland
| | - Michael D Jennions
- Ecology & Evolution, Research School of Biology, The Australian National University, Acton, Canberra, 2601, Australia
| | - Benjamin Geffroy
- MARBEC Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
| | - András Liker
- ELKH-PE Evolutionary Ecology Research Group, University of Pannonia, 8210, Veszprém, Hungary
- Behavioural Ecology Research Group, Center for Natural Sciences, University of Pannonia, 8210, Veszprém, Hungary
| | - Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Leibniz Institute of Primate Biology, 37077, Göttingen, Germany
- Department of Sociobiology/Anthropology, University of Göttingen, 37077, Göttingen, Germany
| | - Franz J Weissing
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Karen L Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT, USA
| | - Therese Hesketh
- Institute of Global Health, University College London, London, UK
- Centre for Global Health, Zhejiang University School of Medicine, Hangzhou, P.R. China
| | - Jérôme Boissier
- IHPE Univ Perpignan Via Domitia, CNRS, Ifremer, Univ Montpellier, Perpignan, France
| | - Caroline Uggla
- Stockholm University Demography Unit, Sociology Department, Stockholm University, 106 91, Stockholm, Sweden
| | - Mike Hollingshaus
- Kem C. Gardner Policy Institute, David Eccles School of Business, University of Utah, Salt Lake City, UT, USA
| | - Tamás Székely
- Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK.
- ELKH-DE Reproductive Strategies Research Group, Department of Zoology and Human Biology, University of Debrecen, H-4032, Debrecen, Hungary.
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Giuntini S, Pedruzzi L. Sex and the patch: the influence of habitat fragmentation on terrestrial vertebrates’ mating strategies. ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2022.2059787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Silvia Giuntini
- Dipartimento di Biologia, Università di Pisa, Via Alessandro Volta 6, Pisa 56126, Italy
- Environmental Analysis and Management Unit, Guido Tosi Research Group, Department of Theoretical and Applied Sciences, Università degli Studi dell’Insubria, Varese, Italy
| | - Luca Pedruzzi
- Dipartimento di Biologia, Università di Pisa, Via Alessandro Volta 6, Pisa 56126, Italy
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O'Brien DM, Keogh JS, Silla AJ, Byrne PG. The unexpected genetic mating system of the red‐backed toadlet (
Pseudophryne coriacea
): A species with prolonged terrestrial breeding and cryptic reproductive behaviour. Mol Ecol 2018; 27:3001-3015. [DOI: 10.1111/mec.14737] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/26/2018] [Accepted: 05/18/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Daniel M. O'Brien
- Centre for Sustainable Ecosystem Solutions School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW Australia
| | - J. Scott Keogh
- Ecology and Evolution Research School of Biology The Australian National University Canberra ACT Australia
| | - Aimee J. Silla
- Centre for Sustainable Ecosystem Solutions School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW Australia
| | - Phillip G. Byrne
- Centre for Sustainable Ecosystem Solutions School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW Australia
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Székely T, Weissing FJ, Komdeur J. Adult sex ratio variation: implications for breeding system evolution. J Evol Biol 2014; 27:1500-12. [DOI: 10.1111/jeb.12415] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 04/16/2014] [Accepted: 04/16/2014] [Indexed: 11/28/2022]
Affiliation(s)
- T. Székely
- Biodiversity Lab; Department of Biology & Biochemistry; University of Bath; Bath UK
- Theoretical Biology; Centre for Ecological and Evolutionary Studies; University of Groningen; Groningen The Netherlands
- Behavioural Ecology and Self-organization; Centre for Ecological and Evolutionary Studies; University of Groningen; Groningen The Netherlands
| | - F. J. Weissing
- Theoretical Biology; Centre for Ecological and Evolutionary Studies; University of Groningen; Groningen The Netherlands
| | - J. Komdeur
- Behavioural Ecology and Self-organization; Centre for Ecological and Evolutionary Studies; University of Groningen; Groningen The Netherlands
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Martínez JJ, de Aranzamendi MC, Masello JF, Bucher EH. Genetic evidence of extra-pair paternity and intraspecific brood parasitism in the monk parakeet. Front Zool 2013; 10:68. [PMID: 24209709 PMCID: PMC3839639 DOI: 10.1186/1742-9994-10-68] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 11/04/2013] [Indexed: 11/16/2022] Open
Abstract
Introduction The monk parakeet (Myiopsitta monachus) is a widespread invasive species native to southern South America that has become established in many regions of the world. Monk parakeets breed in a large, fully enclosed structure built from twigs, which consist of one to many individual brooding chambers. The species has been considered to be socially and genetically monogamous. However, genetic relatedness of adults to juveniles in the native area was found to be lower than expected for monogamy. To assess the significance of this discrepancy, we examined individual and population genetic patterns of microsatellite loci at two sites in Córdoba province, Argentina. Results We sampled 154 nestlings and 42 adults in Córdoba, Argentina. Mean value of pairwise relatedness of nestlings within chambers was about 0.40. Contrarily, relatedness of nestlings between chambers was close to zero. We found a considerable degree of variation in nestling pairwise relatedness and parentage within chambers, including chambers with combinations of unrelated, half-sib, and full-sib nestlings. The proportion of sibling relatedness indicated monogamy in 47% and extra pair-paternity in 40% of the chambers. We also found intra-brood parasitism in 3% of the chambers. Conclusions Our results indicate that the monk parakeet is sexually polygamous in its native range in Argentina, which is consistent with the observed mean value of relatedness of adults to juveniles of about 0.4. We also confirm the existence of intra-brood parasitism. High density of monk parakeets may favor occurrence of extra-pair paternity and intra-brood parasitism in the native sites.
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Affiliation(s)
| | | | | | - Enrique H Bucher
- Centro de Zoología Aplicada, Instituto de Diversidad y Ecología Animal (CONICET-UNC) and Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Avenida Vélez Sarsfield 299, (5000) Córdoba, Argentina.
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Ferrer M, Newton I, Pandolfi M. Small populations and offspring sex-ratio deviations in eagles. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2009; 23:1017-1025. [PMID: 19627325 DOI: 10.1111/j.1523-1739.2009.01215.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Stochastic variation of sex ratio has long been appreciated as a potential factor driving small populations to extinction, but it is not the only source of sex-ratio bias in small populations. We examined whether some consequences of sex allocation could affect extinction risk in small populations of size-dimorphic birds such as eagles. We report variations in sex ratio at fledging from a long-term study of a declining population of Spanish Imperial Eagles (Aquila adalberti). Nestling sex-ratio deviation apparently was mediated by age of breeders, whereas territory quality had no obvious effect. Adult-adult pairs produced the same proportion of both sexes in high- or low-density situations, but pairs with at least one member in nonadult plumage class produced more males. As the population declined over a period of years, the proportion of breeders with immature plumage increased; consequently, the proportion of fledgling males increased. However, when population density was high, the proportion of breeders with immature plumage decreased and more female offspring were produced. This relationship between population density, composition of breeder age, and fledgling sex ratios allowed us to make predictions of extinction risk due to nonstochastic deviations of sex ratio in small, declining populations. In the study population, on the basis of the Vortex simulation results, an estimated reduction of 42.5% in predicted mean time to extinction was attributed solely to biased sex ratio.
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Affiliation(s)
- Miguel Ferrer
- Department of Biodiversity Conservation, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, Avenida de María Luisa s/n, Pabellón del Perú, Seville, Spain.
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Kyle CJ, Karels TJ, Davis CS, Mebs S, Clark B, Strobeck C, Hik DS. Social structure and facultative mating systems of hoary marmots (Marmota caligata). Mol Ecol 2007; 16:1245-55. [PMID: 17391410 DOI: 10.1111/j.1365-294x.2006.03211.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mate-choice theory predicts different optimal mating systems depending on resource availability and habitat stability. Regions with limited resources are thought to promote monogamy. We tested predictions of monogamy in a social rodent, the hoary marmot (Marmota caligata), at the northern climatic extreme of its distribution. Mating systems, social structure and genetic relationships were investigated within and among neighbouring colonies of marmots within a 4 km(2) valley near Kluane National Park, Yukon, Canada, using 21 microsatellite loci. While both monogamous and polygynous populations of hoary marmots have been observed in the southern reaches of this species' range; northern populations of this species are thought to be predominantly monogamous. Contrary to previous studies, we did not find northern hoary marmot social groups to be predominantly monogamous; rather, the mating system seemed to be facultative, varying between monogamy and polygyny within, as well as among, social groups. These findings reveal that the mating systems within colonies of this species are more flexible than previously thought, potentially reflecting local variation in resource availability.
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Affiliation(s)
- C J Kyle
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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