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Maldonado-Chaparro AA, Philson CS, Zhang X, Blumstein DT. Social control is associated with increased reproductive skew in a wild mammal. Biol Lett 2024; 20:20240003. [PMID: 38835239 DOI: 10.1098/rsbl.2024.0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 04/10/2024] [Indexed: 06/06/2024] Open
Abstract
In group-living species, reproductive variation among individuals of the same sex is widespread. By identifying the mechanisms underlying this reproductive skew, we gain fundamental insights into the evolution and maintenance of sociality. A common mechanism, social control, is typically studied by quantifying dominance, which is one of many attributes of sociality that describes how individuals exert influence on others and is an incomprehensive measure of social control as it accounts only for direct relationships. Here, we use the global reaching centrality (GRC), which quantifies the degree of hierarchy in a social network by accounting for both direct and indirect social relationships. Using a wild, free-living population of adult female yellow-bellied marmots (Marmota flaviventris), we found a positive relationship between the reproductive skew index and GRC: more despotic social groups have higher reproductive skew. The GRC was stronger predictor for skew than traditional measures of social control (i.e. dominance). This allows deeper insights into the diverse ways individuals control other group members' reproduction, a core component in the evolution of sociality. Future studies of skew across taxa may profit by using more comprehensive, network-based measures of social control.
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Affiliation(s)
- Adriana A Maldonado-Chaparro
- Department of Ecology and Evolutionary Biology, University of California , Los Angeles, CA 90095-1606, USA
- Department of Biology, Universidad del Rosario , Bogota D.C. 111221, Colombia
- Department of Migration, Max Planck Institute of Animal Behavior , Radolfzell 78457, Germany
| | - Conner S Philson
- Department of Ecology and Evolutionary Biology, University of California , Los Angeles, CA 90095-1606, USA
- Rocky Mountain Biological Laboratory , Crested Butte, CO 81224, USA
- Centre for Research in Animal Behaviour, University of Exeter , Exeter EX4 4QG, UK
| | - Xinping Zhang
- Department of Ecology and Evolutionary Biology, University of California , Los Angeles, CA 90095-1606, USA
| | - Daniel T Blumstein
- Department of Ecology and Evolutionary Biology, University of California , Los Angeles, CA 90095-1606, USA
- Rocky Mountain Biological Laboratory , Crested Butte, CO 81224, USA
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2
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He QQ, Yu JR, Tang SH, Wang MY, Wu JJ, Chen Y, Tao Y, Ji T, Mace R. Jeans and language: kin networks and reproductive success are associated with the adoption of outgroup norms. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230031. [PMID: 38244604 PMCID: PMC10799735 DOI: 10.1098/rstb.2023.0031] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/28/2023] [Indexed: 01/22/2024] Open
Abstract
Traditional norms of human societies in rural China may have changed owing to population expansion, rapid development of the tourism economy and globalization since the 1990s; people from different ethnic groups might adopt cultural traits from outside their group or lose their own culture at different rates. Human behavioural ecology can help to explain adoption of outgroup cultural values. We compared the adoption of four cultural values, specifically speaking outgroup languages/mother tongue and wearing jeans, in two co-residing ethnic groups, the Mosuo and Han. Both groups are learning outgroup traits, including each other's languages through contact in economic activities, education and kin networks, but only the Mosuo are starting to lose their own language. Males are more likely to adopt outgroup values than females in both groups. Females of the two groups are no different in speaking Mandarin and wearing jeans, whereas males do differ, with Mosuo males being keener to adopt them than Han males. The reason might be that Mosuo men experience more reproductive competition over mates, as Mosuo men have larger reproductive skew than others. Moreover, Mosuo men but not others gain fitness benefits from the adoption of Mandarin (they start reproducing earlier than non-speakers). This article is part of the theme issue 'Social norm change: drivers and consequences'.
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Affiliation(s)
- Qiao-Qiao He
- College of Life Science, Shenyang Normal University, Shenyang, Liaoning 110034, People's Republic of China
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Jie-Ru Yu
- College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, People's Republic of China
| | - Song-Hua Tang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Ming-Yang Wang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Jia-Jia Wu
- Life Science, Lanzhou University, Tianshui Road, Chengguan Qu, Lanzhou, Gansu Province 730000, People's Republic of China
| | - Yuan Chen
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Yi Tao
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Ting Ji
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Ruth Mace
- Department of Anthropology, University College London, London WC1H 0BW, UK
- IAST, Toulouse School of Economics, Toulouse, Occitanie, 31080, France
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3
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Ben Mocha Y, Dahan T, Zou Y, Griesser M, Markman S. Evidence for a reproductive sharing continuum in cooperatively breeding mammals and birds: consequences for comparative research. Proc Biol Sci 2023; 290:20230607. [PMID: 37700641 PMCID: PMC10498043 DOI: 10.1098/rspb.2023.0607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/18/2023] [Indexed: 09/14/2023] Open
Abstract
Extreme reproductive skew occurs when a dominant female/male almost monopolizes reproduction within a group of multiple sexually mature females/males, respectively. It is sometimes considered an additional, restrictive criterion to define cooperative breeding. However, datasets that use this restrictive definition to classify species as cooperative breeders systematically overestimate reproductive skew by including groups in which reproduction cannot be shared by definition (e.g. groups with a single female/male). Here, we review the extent of reproductive sharing in 41 mammal and 37 bird species previously classified as exhibiting alloparental care and extreme reproductive skew, while only considering multi-female or multi-male groups. We demonstrate that in groups where unequal reproduction sharing is possible, extreme reproductive skew occurs in a few species only (11/41 mammal species and 12/37 bird species). These results call for significant changes in datasets that classify species' caring and mating system. To facilitate these changes, we provide an updated dataset on reproductive sharing in 63 cooperatively breeding species. At the conceptual level, our findings suggest that reproductive skew should not be a defining criterion of cooperative breeding and support the definition of cooperative breeding as a care system in which alloparents provide systematic care to other group members' offspring.
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Affiliation(s)
- Yitzchak Ben Mocha
- Department of Evolutionary and Environmental Biology, University of Haifa, 3498838 Haifa, Israel
- Department of Biology and Environment, University of Haifa at Oranim, 36006 Tivon, Israel
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Center for the Advanced Study of Collective Behavior, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Tal Dahan
- Department of Biology and Environment, University of Haifa at Oranim, 36006 Tivon, Israel
| | - Yuqi Zou
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Michael Griesser
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Center for the Advanced Study of Collective Behavior, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Department of Collective Behaviour, Max Planck Institute of Animal Behaviour, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Shai Markman
- Department of Evolutionary and Environmental Biology, University of Haifa, 3498838 Haifa, Israel
- Department of Biology and Environment, University of Haifa at Oranim, 36006 Tivon, Israel
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4
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Smith JE, Natterson-Horowitz B, Mueller MM, Alfaro ME. Mechanisms of equality and inequality in mammalian societies. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220307. [PMID: 37381860 DOI: 10.1098/rstb.2022.0307] [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: 02/20/2023] [Accepted: 05/09/2023] [Indexed: 06/30/2023] Open
Abstract
The extent of (in)equality is highly diverse across species of social mammals, but we have a poor understanding of the factors that produce or inhibit equitable social organizations. Here, we adopt a comparative evolutionary perspective to test whether the evolution of social dominance hierarchies, a measure of social inequality in animals, exhibits phylogenetic conservatism and whether interspecific variation in these traits can be explained by sex, age or captivity. We find that hierarchy steepness and directional consistency evolve rapidly without any apparent constraint from evolutionary history. Given this extraordinary variability, we next consider multiple factors that have evolved to mitigate social inequality. Social networks, coalitionary support and knowledge transfer advantage to privilege some individuals over others. Nutritional access and prenatal stressors can impact the development of offspring, generating health disparities with intergenerational consequences. Intergenerational transfer of material resources (e.g. stone tools, food stashes, territories) advantage those who receive. Nonetheless, many of the same social species that experience unequal access to food (survival) and mates (reproduction) engage in levelling mechanisms such as food sharing, adoption, revolutionary coalitions, forgiveness and inequity aversion. Taken together, mammals rely upon a suite of mechanisms of (in)equality to balance the costs and benefits of group living. This article is part of the theme issue 'Evolutionary ecology of inequality'.
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Affiliation(s)
- Jennifer E Smith
- Biology Department, University of Wisconsin Eau Claire, 105 Garfield Avenue, Eau Claire, WI 54702, USA
| | - Barbara Natterson-Horowitz
- School of Medicine, Division of Cardiology, University of California, 650 Charles Young Drive South, A2-237 CHS, Los Angeles, CA 90095, USA
| | - Maddison M Mueller
- Biology Department, University of Wisconsin Eau Claire, 105 Garfield Avenue, Eau Claire, WI 54702, USA
| | - Michael E Alfaro
- Department of Ecology and Evolutionary Biology, University of California, 2149 Terasaki Life Sciences Building, 612 Charles E. Young Drive South, Box 957246, Los Angeles, CA 90095-7246, USA
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5
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Mouginot M, Cheng L, Wilson ML, Feldblum JT, Städele V, Wroblewski EE, Vigilant L, Hahn BH, Li Y, Gilby IC, Pusey AE, Surbeck M. Reproductive inequality among males in the genus Pan. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220301. [PMID: 37381849 DOI: 10.1098/rstb.2022.0301] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/21/2023] [Indexed: 06/30/2023] Open
Abstract
Reproductive inequality, or reproductive skew, drives natural selection, but has been difficult to assess, particularly for males in species with promiscuous mating and slow life histories, such as bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Although bonobos are often portrayed as more egalitarian than chimpanzees, genetic studies have found high male reproductive skew in bonobos. Here, we discuss mechanisms likely to affect male reproductive skew in Pan, then re-examine skew patterns using paternity data from published work and new data from the Kokolopori Bonobo Reserve, Democratic Republic of Congo and Gombe National Park, Tanzania. Using the multinomial index (M), we found considerable overlap in skew between the species, but the highest skew occurred among bonobos. Additionally, for two of three bonobo communities, but no chimpanzee communities, the highest ranking male had greater siring success than predicted by priority-of-access. Thus, an expanded dataset covering a broader demographic range confirms that bonobos have high male reproductive skew. Detailed comparison of data from Pan highlights that reproductive skew models should consider male-male dynamics including the effect of between-group competition on incentives for reproductive concessions, but also female grouping patterns and factors related to male-female dynamics including the expression of female choice. This article is part of the theme issue 'Evolutionary ecology of inequality'.
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Affiliation(s)
- Maud Mouginot
- Department of Anthropology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Leveda Cheng
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany
| | - Michael L Wilson
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, USA
- Institute on the Environment, University of Minnesota, Saint Paul, MN 55108, USA
| | - Joseph T Feldblum
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Veronika Städele
- School of Human Evolution and Social Change, and Institute of Human Origins, Arizona State University, Tempe, AZ 85287, USA
- Cognitive Ethology Laboratory, German Primate Center, Göttingen 37077, Germany
| | - Emily E Wroblewski
- Department of Anthropology, Washington University in St Louis, St Louis, MO 63130, USA
| | - Linda Vigilant
- Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany
| | - Beatrice H Hahn
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yingying Li
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ian C Gilby
- School of Human Evolution and Social Change, and Institute of Human Origins, Arizona State University, Tempe, AZ 85287, USA
| | - Anne E Pusey
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Martin Surbeck
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany
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6
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Ross CT, Hooper PL, Smith JE, Jaeggi AV, Smith EA, Gavrilets S, Zohora FT, Ziker J, Xygalatas D, Wroblewski EE, Wood B, Winterhalder B, Willführ KP, Willard AK, Walker K, von Rueden C, Voland E, Valeggia C, Vaitla B, Urlacher S, Towner M, Sum CY, Sugiyama LS, Strier KB, Starkweather K, Major-Smith D, Shenk M, Sear R, Seabright E, Schacht R, Scelza B, Scaggs S, Salerno J, Revilla-Minaya C, Redhead D, Pusey A, Purzycki BG, Power EA, Pisor A, Pettay J, Perry S, Page AE, Pacheco-Cobos L, Oths K, Oh SY, Nolin D, Nettle D, Moya C, Migliano AB, Mertens KJ, McNamara RA, McElreath R, Mattison S, Massengill E, Marlowe F, Madimenos F, Macfarlan S, Lummaa V, Lizarralde R, Liu R, Liebert MA, Lew-Levy S, Leslie P, Lanning J, Kramer K, Koster J, Kaplan HS, Jamsranjav B, Hurtado AM, Hill K, Hewlett B, Helle S, Headland T, Headland J, Gurven M, Grimalda G, Greaves R, Golden CD, Godoy I, Gibson M, Mouden CE, Dyble M, Draper P, Downey S, DeMarco AL, Davis HE, Crabtree S, Cortez C, Colleran H, Cohen E, Clark G, Clark J, Caudell MA, Carminito CE, Bunce J, Boyette A, Bowles S, Blumenfield T, Beheim B, Beckerman S, Atkinson Q, Apicella C, Alam N, Mulder MB. Reproductive inequality in humans and other mammals. Proc Natl Acad Sci U S A 2023; 120:e2220124120. [PMID: 37216525 PMCID: PMC10235947 DOI: 10.1073/pnas.2220124120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/16/2023] [Indexed: 05/24/2023] Open
Abstract
To address claims of human exceptionalism, we determine where humans fit within the greater mammalian distribution of reproductive inequality. We show that humans exhibit lower reproductive skew (i.e., inequality in the number of surviving offspring) among males and smaller sex differences in reproductive skew than most other mammals, while nevertheless falling within the mammalian range. Additionally, female reproductive skew is higher in polygynous human populations than in polygynous nonhumans mammals on average. This patterning of skew can be attributed in part to the prevalence of monogamy in humans compared to the predominance of polygyny in nonhuman mammals, to the limited degree of polygyny in the human societies that practice it, and to the importance of unequally held rival resources to women's fitness. The muted reproductive inequality observed in humans appears to be linked to several unusual characteristics of our species-including high levels of cooperation among males, high dependence on unequally held rival resources, complementarities between maternal and paternal investment, as well as social and legal institutions that enforce monogamous norms.
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Affiliation(s)
- Cody T. Ross
- Santa Fe Institute, Santa Fe, NM87501
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Paul L. Hooper
- Santa Fe Institute, Santa Fe, NM87501
- Department of Anthropology, University of New Mexico, Albuquerque, NM87131
| | | | - Adrian V. Jaeggi
- Institut für Anthropologie und Anthropologisches Museum, University of Zürich, Zürich8006, Switzerland
| | - Eric Alden Smith
- Department of Anthropology, University of Washington, Seattle, WA98195
| | - Sergey Gavrilets
- Departments of Ecology and Evolutionary Biology and Mathematics, University of Tennessee, Knoxville, TN37996
| | - Fatema tuz Zohora
- International Centre for Diarrheal Disease Research, Dhaka1000, Bangladesh
| | - John Ziker
- Department of Anthropology, Boise State University, Boise, ID83725
| | | | | | - Brian Wood
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
- Department of Anthropology, University of California, Los Angeles, CA90095
| | | | - Kai P. Willführ
- Institute for Social Science, University of Oldenburg, Oldenburg26129, Germany
| | - Aiyana K. Willard
- Centre for Culture and Evolution, Brunel University, LondonUB8 3PH, United Kingdom
| | - Kara Walker
- College of Veterinary Medicine, North Carolina State University, Raleigh, NC27695
| | | | - Eckart Voland
- Institute for Philosophy, Justus-Liebig University, Giessen35390, Germany
| | | | - Bapu Vaitla
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Samuel Urlacher
- Department of Anthropology, Baylor University, Waco, TX76706
- Canadian Institute for Advanced Research, Toronto, CAM5G 1M1
| | - Mary Towner
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK74078
| | - Chun-Yi Sum
- College of General Studies, Boston University, Boston, MA02215
| | | | - Karen B. Strier
- Department of Zoology, University of Wisconsin, Madison, WI53706
| | | | - Daniel Major-Smith
- Department of Anthropology and Archaeology, University of Bristol, BristolBS8 1QU, United Kingdom
| | - Mary Shenk
- Department of Anthropology, Pennsylvania State University, University Park, PA16802
| | - Rebecca Sear
- Department of Population Health, London School of Hygiene and Tropical Medicine, LondonWC1E 7HT, United Kingdom
| | - Edmond Seabright
- Department of Anthropology, University of New Mexico, Albuquerque, NM87131
| | - Ryan Schacht
- Department of Anthropology, East Carolina University, Greenville, NC27858
| | - Brooke Scelza
- Department of Anthropology, University of California, Los Angeles, CA90095
| | - Shane Scaggs
- Department of Anthropology, Ohio State University, Columbus, OH43210
| | - Jonathan Salerno
- Department of Human Dimensions of Natural Resources, Colorado State University, Fort Collins, CO80523
| | - Caissa Revilla-Minaya
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Daniel Redhead
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Anne Pusey
- Department of Evolutionary Anthropology, Duke University, Durham, NC27708
| | - Benjamin Grant Purzycki
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
- Department of the Study of Religion, Aarhus University, Aarhus8000, Denmark
| | - Eleanor A. Power
- Santa Fe Institute, Santa Fe, NM87501
- Department of Methodology, London School of Economics and Political Science, LondonWC2A 2AE, United Kingdom
| | - Anne Pisor
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
- Department of Anthropology, Washington State University, Pullman, WA99164
| | - Jenni Pettay
- Department of Biology, University of Turku, Turku20014, Finland
| | - Susan Perry
- Department of Anthropology, University of California, Los Angeles, CA90095
| | - Abigail E. Page
- Department of Population Health, London School of Hygiene and Tropical Medicine, LondonWC1E 7HT, United Kingdom
| | - Luis Pacheco-Cobos
- Facultad de Ciencias Biológicas y Agropecuarias, Universidad Veracruzana, Veracruz94294, Mexico
| | - Kathryn Oths
- Department of Anthropology, University of Alabama, Tuscaloosa, AL35487
| | - Seung-Yun Oh
- Korea Insurance Research Institute, Seoul150-606, Korea
| | - David Nolin
- Department of Sociology, University of Massachusetts, Amherst, MA01003
| | - Daniel Nettle
- Département d’Etudes Cognitives, Ecole Normale Supérieure, Université PSL, Paris75230, France
| | - Cristina Moya
- Department of Anthropology, University of California, Davis, CA95616
| | - Andrea Bamberg Migliano
- Institut für Anthropologie und Anthropologisches Museum, University of Zürich, Zürich8006, Switzerland
| | - Karl J. Mertens
- Department of Anthropology, Boise State University, Boise, ID83725
| | - Rita A. McNamara
- School of Psychology, Victoria University of Wellington, Wellington6012, New Zealand
| | - Richard McElreath
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Siobhan Mattison
- Department of Anthropology, University of New Mexico, Albuquerque, NM87131
| | - Eric Massengill
- Department of Anthropology, University of New Mexico, Albuquerque, NM87131
| | - Frank Marlowe
- Department of Biological Anthropology, University of Cambridge, CambridgeCB2 1TN, United Kingdom
| | - Felicia Madimenos
- Department of Anthropology, Queens College (CUNY), New York, NY11367
| | - Shane Macfarlan
- Department of Anthropology, University of Utah, Salt Lake City, UT84112
| | - Virpi Lummaa
- Department of Biology, University of Turku, Turku20014, Finland
| | - Roberto Lizarralde
- Facultad de Ciencias Económicas y Sociales, Universidad Central de Venezuela, Caracas1010A, Venezuela
| | - Ruizhe Liu
- Department of Anthropology, University of New Mexico, Albuquerque, NM87131
| | - Melissa A. Liebert
- Department of Anthropology, Northern Arizona University, Flagstaff, AZ86011
| | - Sheina Lew-Levy
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
- Department of Psychology, Durham University, DurhamDH1 3LE, United Kingdom
| | - Paul Leslie
- Department of Anthropology, University of North Carolina, Chapel Hill, NC27599
| | | | - Karen Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT84112
| | - Jeremy Koster
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH45221
| | | | | | - A. Magdalena Hurtado
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ85287
| | - Kim Hill
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ85287
| | - Barry Hewlett
- Department of Anthropology, Washington State University, Pullman, WA99164
| | - Samuli Helle
- Department of Biology, University of Turku, Turku20014, Finland
| | | | | | - Michael Gurven
- Department of Anthropology, University of California, Santa Barbara, CA93106
| | | | - Russell Greaves
- Department of Anthropology, University of Utah, Salt Lake City, UT84112
| | - Christopher D. Golden
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Irene Godoy
- Department of Animal Behaviour, Bielefeld University, Bielefeld33615, Germany
| | - Mhairi Gibson
- Department of Anthropology and Archaeology, University of Bristol, BristolBS8 1QU, United Kingdom
| | - Claire El Mouden
- School of Anthropology and Museum Ethnography, University of Oxford, OxfordOX1 2JD, United Kingdom
| | - Mark Dyble
- Department of Anthropology, University College London, LondonWC1E 6BT, United Kingdom
| | - Patricia Draper
- School of Global Integrative Studies, University of Nebraska, Lincoln, NE68588
| | - Sean Downey
- Department of Anthropology, Ohio State University, Columbus, OH43210
| | | | | | - Stefani Crabtree
- Santa Fe Institute, Santa Fe, NM87501
- Department of Environment and Society, Utah State University, Logan, UT84322
| | - Carmen Cortez
- Department of Anthropology, University of California, Davis, CA95616
| | - Heidi Colleran
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Emma Cohen
- School of Anthropology and Museum Ethnography, University of Oxford, OxfordOX1 2JD, United Kingdom
| | - Gregory Clark
- Department of Economics, University of California, Davis, CA95616
| | | | - Mark A. Caudell
- Department of Anthropology, Washington State University, Pullman, WA99164
| | - Chelsea E. Carminito
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH45221
| | - John Bunce
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Adam Boyette
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | | | - Tami Blumenfield
- Department of Anthropology, University of New Mexico, Albuquerque, NM87131
- School of Ethnology and Sociology, Yunnan University, Yunnan650106, China
| | - Bret Beheim
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Stephen Beckerman
- Department of Anthropology, Pennsylvania State University, University Park, PA16802
| | - Quentin Atkinson
- School of Psychology, University of Auckland, Auckland1010, New Zealand
| | - Coren Apicella
- Department of Psychology, University of Pennsylvania, Philadelphia, PA19104
| | - Nurul Alam
- International Centre for Diarrheal Disease Research, Dhaka1000, Bangladesh
| | - Monique Borgerhoff Mulder
- Santa Fe Institute, Santa Fe, NM87501
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
- Department of Anthropology, University of California, Davis, CA95616
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7
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Dyble M, Clutton-Brock TH. Turnover in male dominance offsets the positive effect of polygyny on within-group relatedness. Behav Ecol 2023; 34:261-268. [PMID: 36998996 PMCID: PMC10047635 DOI: 10.1093/beheco/arac121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 11/12/2022] [Accepted: 12/05/2022] [Indexed: 02/07/2023] Open
Abstract
Abstract
Evidence of an association between cooperative breeding systems and average coefficients of relatedness between group members in vertebrates have led to increased interest in the social and ecological factors affecting average kinship within groups. Previous studies have suggested that polygynous mating systems and high degrees of male reproductive skew increase average relatedness because they increase the proportion of offspring born in each group that are paternal siblings. Although this may be the case in semelparous organisms, in many multiparous polygynous animals, intense competition between males shortens the breeding tenure of males and leads to their frequent replacement by competitors which reduces paternal relatedness and average kinship between members of multigenerational groups. Here, we explore the interaction between male reproductive skew and the frequency of turnover in breeding males and its effects on within-group relatedness. Our theoretical model shows that increases in rates of dominance turnover in polygynous systems can offset the positive effect of male skew on relatedness between group members within seasons, showing that polygynous mating systems will not necessarily lead to significant increases in average relatedness, especially in species where there is extensive overlap between generations among group members.
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Affiliation(s)
- Mark Dyble
- Department of Anthropology, University College London , 14 Taviton Street, London WC1H 0BW , UK
| | - Tim H Clutton-Brock
- Department of Zoology, University of Cambridge , Downing Street, Cambridge CB2 3EJ , UK
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8
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Leimar O, Bshary R. Effects of local versus global competition on reproductive skew and sex differences in social dominance behaviour. Proc Biol Sci 2022; 289:20222081. [PMID: 36448421 PMCID: PMC9709658 DOI: 10.1098/rspb.2022.2081] [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: 12/05/2022] Open
Abstract
Social hierarchies are often found in group-living animals. The hierarchy position can influence reproductive success (RS), with a skew towards high-ranking individuals. The amount of aggression in social dominance varies greatly, both between species and between males and females within species. Using game theory we study this variation by taking into account the degree to which reproductive competition in a social group is mainly local to the group, emphasizing within-group relative RS, or global to a larger population, emphasizing an individual's absolute RS. Our model is similar to recent approaches in that reinforcement learning is used as a behavioural mechanism allowing social-hierarchy formation. We test two hypotheses. The first is that local competition should favour the evolution of mating or foraging interference, and thus of reproductive skew. Second, decreases in reproductive output caused by an individual's accumulated fighting damage, such as reduced parenting ability, will favour less intense aggression but should have little influence on reproductive skew. From individual-based simulations of the evolution of social dominance and interference, we find support for both hypotheses. We discuss to what extent our results can explain observed sex differences in reproductive skew and social dominance behaviour.
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Affiliation(s)
- Olof Leimar
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden
| | - Redouan Bshary
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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9
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Smith JE, Fichtel C, Holmes RK, Kappeler PM, van Vugt M, Jaeggi AV. Sex bias in intergroup conflict and collective movements among social mammals: male warriors and female guides. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210142. [PMID: 35369756 DOI: 10.1098/rstb.2021.0142] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Intergroup conflict is a major evolutionary force shaping animal and human societies. Males and females should, on average, experience different costs and benefits for participating in collective action. Specifically, among mammals, male fitness is generally limited by access to mates whereas females are limited by access to food and safety. Here we analyse sex biases among 72 species of group-living mammals in two contexts: intergroup conflict and collective movements. Our comparative phylogenetic analyses show that the modal mammalian pattern is male-biased participation in intergroup conflict and female-biased leadership in collective movements. However, the probability of male-biased participation in intergroup conflicts decreased and female-biased participation increased with female-biased leadership in movements. Thus, female-biased participation in intergroup conflict only emerged in species with female-biased leadership in collective movements, such as in spotted hyenas and some lemurs. Sex differences are probably attributable to costs and benefits of participating in collective movements (e.g. towards food, water, safety) and intergroup conflict (e.g. access to mates or resources, risk of injury). Our comparative review offers new insights into the factors shaping sex bias in leadership across social mammals and is consistent with the 'male warrior hypothesis' which posits evolved sex differences in human intergroup psychology. This article is part of the theme issue 'Intergroup conflict across taxa'.
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Affiliation(s)
- Jennifer E Smith
- Biology Department, Mills College, 5000 MacArthur Boulevard, Oakland, CA 94631, USA
| | - Claudia Fichtel
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Rose K Holmes
- Biology Department, Mills College, 5000 MacArthur Boulevard, Oakland, CA 94631, USA
| | - Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany.,Department Anthropology/Sociobiology, University of Göttingen, Göttingen, Germany
| | - Mark van Vugt
- Department of Experimental and Applied Psychology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Adrian V Jaeggi
- Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland
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10
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Strauss ED, Shizuka D. The ecology of wealth inequality in animal societies. Proc Biol Sci 2022; 289:20220500. [PMID: 35506231 PMCID: PMC9065979 DOI: 10.1098/rspb.2022.0500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 03/23/2022] [Indexed: 11/30/2022] Open
Abstract
Individuals vary in their access to resources, social connections and phenotypic traits, and a central goal of evolutionary biology is to understand how this variation arises and influences fitness. Parallel research on humans has focused on the causes and consequences of variation in material possessions, opportunity and health. Central to both fields of study is that unequal distribution of wealth is an important component of social structure that drives variation in relevant outcomes. Here, we advance a research framework and agenda for studying wealth inequality within an ecological and evolutionary context. This ecology of inequality approach presents the opportunity to reintegrate key evolutionary concepts as different dimensions of the link between wealth and fitness by (i) developing measures of wealth and inequality as taxonomically broad features of societies, (ii) considering how feedback loops link inequality to individual and societal outcomes, (iii) exploring the ecological and evolutionary underpinnings of what makes some societies more unequal than others, and (iv) studying the long-term dynamics of inequality as a central component of social evolution. We hope that this framework will facilitate a cohesive understanding of inequality as a widespread biological phenomenon and clarify the role of social systems as central to evolutionary biology.
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Affiliation(s)
- Eli D. Strauss
- Department of Collective Behaviour, Max Planck Institute of Animal Behaviour, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
- BEACON Center for the Study of Evolution in Action, Michigan State University, Lansing, MI, USA
| | - Daizaburo Shizuka
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
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11
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Leimar O, Bshary R. Reproductive skew, fighting costs, and winner-loser effects in social-dominance evolution. J Anim Ecol 2022; 91:1036-1046. [PMID: 35304750 PMCID: PMC9315160 DOI: 10.1111/1365-2656.13691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/02/2022] [Indexed: 11/28/2022]
Abstract
1. Social hierarchies are often found in group-living animals and can be formed through pairwise aggressive interactions. The dominance rank can influence reproductive success (RS) with a skew towards high-ranking individuals. 2. Using game theory we investigate how the opportunity for differently ranked individuals to achieve RS influences the costs of hierarchy formation and the strength of winner and loser effects. 3. In our model, individuals adjust their aggressive and submissive behaviour towards others through reinforcement learning. The learning is based on rewards and penalties, which depend on relative fighting ability. From individual-based simulations we determine evolutionary equilibria of traits such as learning rates. We examine situations that differ in the extent of monopolisation of contested RS by dominants and in the proportion of total RS that is contested. 4. The model implements two kinds of fighting costs: a decrease in effective fighting ability from damage (loss of condition), and a risk of mortality that increases with the total accumulated damage. Either of these costs can limit the amount of fighting. 5. We find that stable dominance hierarchies form, with a positive correlation between dominance position and fighting ability. The accumulated costs differ between dominance positions, with the highest costs paid by low or intermediately ranked individuals. Costs tend to be higher in high-skew situations. 6. We identify a 'stay-in, opt-out' syndrome, comprising a range from weaker (stay-in) to stronger (opt-out) winner-loser effects. We interpret the opt-out phenotype to be favoured by selection on lower-ranked individuals to opt out of contests over social dominance, because it is more pronounced when more of the total RS is uncontested. 7. We discuss our results in relation to field and experimental observations and argue that there is a need for empirical investigation of the behaviour and reproductive success of lower-ranked individuals.
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Affiliation(s)
- Olof Leimar
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Redouan Bshary
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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12
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Maag N, Paniw M, Cozzi G, Manser M, Clutton-Brock T, Ozgul A. Dispersal decreases survival but increases reproductive opportunities for subordinates in a cooperative breeder. Am Nat 2022; 199:679-690. [DOI: 10.1086/719029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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13
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Smith JE, Natterson-Horowitz B, Alfaro ME. The nature of privilege: intergenerational wealth in animal societies. Behav Ecol 2021. [DOI: 10.1093/beheco/arab137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Wealth inequality is widespread across human societies, from pastoral and small-scale agricultural groups to large modern social structures. The intergenerational transfer of wealth privileges some individuals over others through the transmission of resources external to an individual organism. Privileged access to household wealth (e.g., land, shelter, silver) positively influences the destinies of some (and their descendants) over others in human societies. Strikingly parallel phenomena exist in animal societies. Inheritance of nongenetic commodities (e.g., a nest, territory, tool) external to an individual also contributes greatly to direct fitness in animals. Here, we illustrate the evolutionary diversity of privilege and its disparity-generating effects on the evolutionary trajectories of lineages across the Tree of Life. We propose that integration of approaches used to study these patterns in humans may offer new insights into a core principle from behavioral ecology—differential access to inherited resources—and help to establish a broad, comparative framework for studying inequality in animals.
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Affiliation(s)
| | - B Natterson-Horowitz
- School of Medicine, Division of Cardiology, University of California, Los Angeles, CA, USA
| | - Michael E Alfaro
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
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14
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Schmid-Hempel P. Sociality and parasite transmission. Behav Ecol Sociobiol 2021; 75:156. [PMID: 34720348 PMCID: PMC8540878 DOI: 10.1007/s00265-021-03092-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/23/2021] [Accepted: 09/27/2021] [Indexed: 11/18/2022]
Abstract
Parasites and their social hosts form many different relationships. But what kind of selection regimes are important? A look at the parameters that determine fitness of the two parties suggests that social hosts differ from solitary ones primarily in the structure of transmission pathways. Because transmission is, both, the physical encounter of a new host and infecting it, several different elements determine parasite transmission success. These include spatial distance, genetic distance, or the temporal and ecological niche overlaps. Combing these elements into a ‘generalized transmission distance’ that determines parasite fitness aids in the identification of the critical steps. For example, short-distance transmission to genetically similar hosts within the social group is the most frequent process under sociality. Therefore, spatio-genetical distances are the main driver of parasite fitness. Vice versa, the generalized distance identifies the critical host defences. In this case, host defences should be primarily selected to defend against the within-group spread of an infection, especially among closely related group members.
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Affiliation(s)
- Paul Schmid-Hempel
- Institute of Integrative Biology (IBZ), ETH Zürich, ETH-Zentrum CHN, Universitätstrasse 16, CH-8092 Zürich, Switzerland
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15
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Šmejkal M, Bartoň D, Brabec M, Sajdlová Z, Souza AT, Moraes KR, Soukalová K, Blabolil P, Vejřík L, Kubečka J. Climbing up the ladder: male reproductive behaviour changes with age in a long-lived fish. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-020-02961-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Abstract
High reproductive performance is the key attribute of male fitness, especially due to the high reproductive skew among the males of most animal species. Males of long-lived iteroparous species have opportunities to improve upon their previous reproductive attempts with increasing age. We collected individual-specific reproductive behaviour and age data on a cyprinid fish, the asp (Leuciscus aspius), from 2015 to 2019. We tested whether males changed their performance over time using a unique dataset where individual performance was recorded yearly with passive telemetry. Individual fish behaviour was tracked from one to five reproductive seasons at least a year after the tagging. Fish were scored by measures of quality (first arrival time, number of visits and time spent in the reproductive grounds, and encountered proportion of males to all adult fish). In general, fish improved in the first three metrics with age, suggesting a shift towards behaviours likely to enhance reproductive success as individuals aged. A larger size at tagging was predictive of earlier fish arrival on the spawning ground in subsequent years. Our study therefore demonstrates the importance of age as a factor when considering the potential reproductive success of long-lived fish species.
Significance statement
High reproductive performance is the key attribute of male fitness. Males of long-lived species reproducing multiple times in their life have opportunities to improve upon their previous reproductive performance with increasing age. In this 5-year study, we tracked a large cyprinid fish with telemetry systems during their reproduction. We investigated the age-related behavioural changes in males and demonstrated the improvement of male reproductive timing and length of stay with potential repercussions for male’s reproductive output. We emphasize the importance of old and experienced individuals among the fish population, which are often targeted and selectively removed from the human-managed waters.
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