1
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Rodrigues AMM, Gardner A. Transmission of social status drives cooperation and offspring philopatry. Proc Biol Sci 2023; 290:20231314. [PMID: 38018113 PMCID: PMC10685119 DOI: 10.1098/rspb.2023.1314] [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: 06/13/2023] [Accepted: 10/21/2023] [Indexed: 11/30/2023] Open
Abstract
The evolution of cooperation depends on two crucial overarching factors: relatedness, which describes the extent to which the recipient shares genes in common with the actor; and quality, which describes the recipient's basic capacity to transmit genes into the future. While most research has focused on relatedness, there is a growing interest in understanding how quality modulates the evolution of cooperation. However, the impact of inheritance of quality on the evolution of cooperation remains largely unexplored, especially in spatially structured populations. Here, we develop a mathematical model to understand how inheritance of quality, in the form of social status, influences the evolution of helping and harming within social groups in a viscous-population setting. We find that: (1) status-reversal transmission, whereby parental and offspring status are negatively correlated, strongly inhibits the evolution of cooperation, with low-status individuals investing less in cooperation and high-status individuals being more prone to harm; (2) transmission of high status promotes offspring philopatry, with more cooperation being directed towards the higher-dispersal social class; and (3) fertility inequality and inter-generational status inheritance reduce within-group conflict. Overall, our study highlights the importance of considering different mechanisms of phenotypic inheritance, including social support, and their potential interactions in shaping animal societies.
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Affiliation(s)
- António M. M. Rodrigues
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT 06511, USA
- School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
| | - Andy Gardner
- School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
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2
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Avila P, Mullon C. Evolutionary game theory and the adaptive dynamics approach: adaptation where individuals interact. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210502. [PMID: 36934752 PMCID: PMC10024992 DOI: 10.1098/rstb.2021.0502] [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: 08/18/2022] [Accepted: 01/16/2023] [Indexed: 03/21/2023] Open
Abstract
Evolutionary game theory and the adaptive dynamics approach have made invaluable contributions to understanding how gradual evolution leads to adaptation when individuals interact. Here, we review some of the basic tools that have come out of these contributions to model the evolution of quantitative traits in complex populations. We collect together mathematical expressions that describe directional and disruptive selection in class- and group-structured populations in terms of individual fitness, with the aims of bridging different models and interpreting selection. In particular, our review of disruptive selection suggests there are two main paths that can lead to diversity: (i) when individual fitness increases more than linearly with trait expression; (ii) when trait expression simultaneously increases the probability that an individual is in a certain context (e.g. a given age, sex, habitat, size or social environment) and fitness in that context. We provide various examples of these and more broadly argue that population structure lays the ground for the emergence of polymorphism with unique characteristics. Beyond this, we hope that the descriptions of selection we present here help see the tight links among fundamental branches of evolutionary biology, from life history to social evolution through evolutionary ecology, and thus favour further their integration. This article is part of the theme issue 'Half a century of evolutionary games: a synthesis of theory, application and future directions'.
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Affiliation(s)
- Piret Avila
- Institute for Advanced Studies in Toulouse, Université Toulouse 1 Capitole, 31080 Toulouse, France
| | - Charles Mullon
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
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3
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Kümmerli R, Frank SA. Evolutionary explanations for heterogeneous behavior in clonal bacterial populations. Trends Microbiol 2023:S0966-842X(23)00115-4. [PMID: 37117073 DOI: 10.1016/j.tim.2023.04.003] [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: 03/08/2023] [Revised: 04/06/2023] [Accepted: 04/06/2023] [Indexed: 04/30/2023]
Abstract
Cellular heterogeneity in clonal bacterial populations is widespread. Division of labor and bet hedging are common adaptive explanations for the function of such heterogeneity. We suggest group-level phenotypes via shareable molecules and variation in cellular vigor as two alternative evolutionary explanations for bacterial cellular heterogeneity.
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Affiliation(s)
- Rolf Kümmerli
- Department of Quantitative Biomedicine, University of Zürich, Zürich, Switzerland.
| | - Steven A Frank
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
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4
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Rodrigues AMM, Barker JL, Robinson EJH. From inter-group conflict to inter-group cooperation: insights from social insects. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210466. [PMID: 35369743 PMCID: PMC8977659 DOI: 10.1098/rstb.2021.0466] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/22/2022] [Indexed: 01/18/2023] Open
Abstract
The conflict between social groups is widespread, often imposing significant costs across multiple groups. The social insects make an ideal system for investigating inter-group relationships, because their interaction types span the full harming-helping continuum, from aggressive conflict, to mutual tolerance, to cooperation between spatially separate groups. Here we review inter-group conflict in the social insects and the various means by which they reduce the costs of conflict, including individual or colony-level avoidance, ritualistic behaviours and even group fusion. At the opposite extreme of the harming-helping continuum, social insect groups may peacefully exchange resources and thus cooperate between groups in a manner rare outside human societies. We discuss the role of population viscosity in favouring inter-group cooperation. We present a model encompassing intra- and inter-group interactions, and local and long-distance dispersal. We show that in this multi-level population structure, the increased likelihood of cooperative partners being kin is balanced by increased kin competition, such that neither cooperation (helping) nor conflict (harming) is favoured. This model provides a baseline context in which other intra- and inter-group processes act, tipping the balance toward or away from conflict. We discuss future directions for research into the ecological factors shaping the evolution of inter-group interactions. This article is part of the theme issue 'Intergroup conflict across taxa'.
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Affiliation(s)
| | - Jessica L. Barker
- Interacting Minds Centre, Aarhus University, Aarhus, 8000 Aarhus, Denmark
- Department of Population Health Sciences, University of Alaska, Anchorage, AK 99503, USA
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5
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Rodrigues AMM, Gardner A. Reproductive value and the evolution of altruism. Trends Ecol Evol 2021; 37:346-358. [PMID: 34949484 DOI: 10.1016/j.tree.2021.11.007] [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: 09/01/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 11/26/2022]
Abstract
Altruism is favored by natural selection provided that it delivers sufficient benefits to relatives. An altruist's valuation of her relatives depends upon the extent to which they carry copies of her genes - relatedness - and also on the extent to which they are able to transmit their own genes to future generations - reproductive value. However, although relatedness has received a great deal of attention with regard to altruism, reproductive value has been surprisingly neglected. We review how reproductive value modulates patterns of altruism in relation to individual differences in age, sex, and general condition, and discuss how social partners may manipulate each other's reproductive value to incentivize altruism. This topic presents opportunities for tight interplay between theoretical and empirical research.
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Affiliation(s)
- António M M Rodrigues
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA.
| | - Andy Gardner
- School of Biology, University of St Andrews, Greenside Place, St Andrews KY16 9TH, UK
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6
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Moran NP, Caspers BA, Chakarov N, Ernst UR, Fricke C, Kurtz J, Lilie ND, Lo LK, Müller C, R R, Takola E, Trimmer PC, van Benthem KJ, Winternitz J, Wittmann MJ. Shifts between cooperation and antagonism driven by individual variation: a systematic synthesis review. OIKOS 2021. [DOI: 10.1111/oik.08201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Nicholas P. Moran
- Centre for Ocean Life DTU‐Aqua, Technical Univ. of Denmark Lyngby Denmark
- Dept of Evolutionary Biology, Bielefeld Univ. Bielefeld Germany
| | | | | | - Ulrich R. Ernst
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
- Apicultural State Inst., Univ. of Hohenheim Stuttgart Germany
| | - Claudia Fricke
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | - Joachim Kurtz
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | - Navina D. Lilie
- Dept of Evolutionary Biology, Bielefeld Univ. Bielefeld Germany
- Dept of Animal Behaviour, Bielefeld Univ. Bielefeld Germany
| | - Lai Ka Lo
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | | | - Reshma R
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | - Elina Takola
- Inst. of Ecology and Evolution, Friedrich Schiller Univ. Jena Jena Germany
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7
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Iritani R, West SA, Abe J. Cooperative interactions among females can lead to even more extraordinary sex ratios. Evol Lett 2021; 5:370-384. [PMID: 34367662 PMCID: PMC8327954 DOI: 10.1002/evl3.217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/04/2021] [Accepted: 01/15/2021] [Indexed: 11/29/2022] Open
Abstract
Hamilton's local mate competition theory provided an explanation for extraordinary female-biased sex ratios in a range of organisms. When mating takes place locally, in structured populations, a female-biased sex ratio is favored to reduce competition between related males, and to provide more mates for males. However, there are a number of wasp species in which the sex ratios appear to more female biased than predicted by Hamilton's theory. It has been hypothesized that the additional female bias in these wasp species results from cooperative interactions between females. We investigated theoretically the extent to which cooperation between related females can interact with local mate competition to favor even more female-biased sex ratios. We found that (i) cooperation between females can lead to sex ratios that are more female biased than predicted by local competition theory alone, and (ii) sex ratios can be more female biased when the cooperation occurs from offspring to mothers before dispersal, rather than cooperation between siblings after dispersal. Our models formally confirm the verbal predictions made in previous experimental studies, which could be applied to a range of organisms. Specifically, cooperation can help explain sex ratio biases in Sclerodermus and Melittobia wasps, although quantitative comparisons between predictions and data suggest that some additional factors may be operating.
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Affiliation(s)
- Ryosuke Iritani
- Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)RIKENWako351‐0198Japan
| | - Stuart A. West
- Department of ZoologyUniversity of OxfordOxfordOX1 3PSUnited Kingdom
| | - Jun Abe
- Faculty of Liberal ArtsMeiji Gakuin UniversityYokohama244–8539Japan
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8
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Rodrigues AMM, Estrela S, Brown SP. Community lifespan, niche expansion and the evolution of interspecific cooperation. J Evol Biol 2020; 34:352-363. [PMID: 33238064 DOI: 10.1111/jeb.13739] [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: 07/12/2020] [Revised: 09/25/2020] [Accepted: 11/06/2020] [Indexed: 11/29/2022]
Abstract
Microbes live in dense and diverse communities where they deploy many traits that promote the growth and survival of neighbouring species, all the while also competing for shared resources. Because microbial communities are highly dynamic, the costs and benefits of species interactions change over the growth cycle of a community. How mutualistic interactions evolve under such demographic and ecological conditions is still poorly understood. Here, we develop an eco-evolutionary model to explore how different forms of helping with distinct fitness effects (rate-enhancing and yield-enhancing) affect the multiple phases of community growth, and its consequences for the evolution of mutualisms. We specifically focus on a form of yield-enhancing trait in which cooperation augments the common pool of resources, termed niche expansion. We show that although mutualisms in which cooperation increases partners growth rate are generally favoured at early stages of community growth, niche expansion can evolve at later stages where densities are high. Further, we find that niche expansion can promote the evolution of reproductive restraint, in which a focal species adaptively reduces its own growth rate to increase the density of partner species. Our findings suggest that yield-enhancing mutualisms are more prevalent in stable habitats with a constant supply of resources, and where populations typically live at high densities. In general, our findings highlight the need to integrate different components of population growth in the analysis of mutualisms to understand the composition and function of microbial communities.
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Affiliation(s)
| | - Sylvie Estrela
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Sam P Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
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9
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Rodrigues AMM. Resource availability and adjustment of social behaviour influence patterns of inequality and productivity across societies. PeerJ 2018; 6:e5488. [PMID: 30310732 PMCID: PMC6173167 DOI: 10.7717/peerj.5488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 07/30/2018] [Indexed: 11/20/2022] Open
Abstract
Animal societies vary widely in the diversity of social behaviour and the distribution of reproductive shares among their group members. It has been shown that individual condition can lead to divergent social roles and that social specialisation can cause an exacerbation or a mitigation of the inequality among group members within a society. This work, however, has not investigated cases in which resource availability varies between different societies, a factor that is thought to explain variation in the level of cooperation and the disparities in reproductive shares within each social group. In this study, I focus on how resource availability mediates the expression of social behaviour and how this, in turn, mediates inequality both within and between groups. I find that when differences in resource availability between societies persist over time, resource-rich societies become more egalitarian. Because lower inequality improves the productivity of a society, the inequality between resource-rich and resource-poor societies rises. When resource availability fluctuates over time, resource-rich societies tend to become more unequal. Because inequality hinders the productivity of a society, the inequality between resource-rich and resource-poor societies falls. From the evolutionary standpoint, my results show that spatial and temporal variation in resource availability may exert a strong influence on the level of inequality both within and between societies.
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Affiliation(s)
- António M M Rodrigues
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom.,Wolfson College, Cambridge, United Kingdom
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10
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Rodrigues AMM. Ecological succession, patch age and the evolution of social behaviour and terminal investment. OIKOS 2018. [DOI: 10.1111/oik.05341] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- António M. M. Rodrigues
- Dept of Zoology, Univ. of Cambridge; Downing Street Cambridge CB2 3EJ UK
- Wolfson College; Barton Road Cambridge UK
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11
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Cooper GA, Levin SR, Wild G, West SA. Modeling relatedness and demography in social evolution. Evol Lett 2018. [DOI: 10.1002/evl3.69] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Guy A. Cooper
- Department of Zoology; University of Oxford; Oxford OX1 3PS United Kingdom
| | - Samuel R. Levin
- Department of Zoology; University of Oxford; Oxford OX1 3PS United Kingdom
| | - Geoff Wild
- Department of Applied Mathematics; University of Western Ontario; London Ontario N6A 3K7 Canada
| | - Stuart A. West
- Department of Zoology; University of Oxford; Oxford OX1 3PS United Kingdom
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12
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Rodrigues AMM. Demography, life history and the evolution of age-dependent social behaviour. J Evol Biol 2018; 31:1340-1353. [DOI: 10.1111/jeb.13308] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 04/15/2018] [Accepted: 06/12/2018] [Indexed: 11/29/2022]
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13
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Rodrigues AMM, Taylor TB. Ecological and demographic correlates of cooperation from individual to budding dispersal. J Evol Biol 2018; 31:1058-1070. [DOI: 10.1111/jeb.13286] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/06/2018] [Accepted: 04/11/2018] [Indexed: 11/30/2022]
Affiliation(s)
| | - Tiffany B. Taylor
- The Milner Centre for Evolution & Department of Biology and Biochemistry; University of Bath; Bath UK
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14
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Mavridou DAI, Gonzalez D, Kim W, West SA, Foster KR. Bacteria Use Collective Behavior to Generate Diverse Combat Strategies. Curr Biol 2018; 28:345-355.e4. [PMID: 29395918 DOI: 10.1016/j.cub.2017.12.030] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 11/06/2017] [Accepted: 12/14/2017] [Indexed: 01/06/2023]
Abstract
Animals have evolved a wide diversity of aggressive behavior often based upon the careful monitoring of other individuals. Bacteria are also capable of aggression, with many species using toxins to kill or inhibit their competitors. Like animals, bacteria also have systems to monitor others during antagonistic encounters, but how this translates into behavior remains poorly understood. Here, we use colonies of Escherichia coli carrying colicin-encoding plasmids as a model for studying antagonistic behavior. We show that in the absence of threat, dispersed cells with low reproductive value produce colicin toxins spontaneously, generating efficient pre-emptive attacks. Cells can also respond conditionally to toxins released by clonemates via autoinduction or other genotypes via competition sensing. The strength of both pre-emptive and responsive attacks varies widely between strains. We demonstrate that this variability occurs easily through mutation by rationally engineering strains to recapitulate the diversity in naturally occurring strategies. Finally, we discover that strains that can detect both competitors and clonemates are capable of massive coordinated attacks on competing colonies. This collective behavior protects established colonies from competitors, mirroring the evolution of alarm calling in the animal world.
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Affiliation(s)
- Despoina A I Mavridou
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK; Calleva Research Centre for Evolution and Human Sciences, Magdalen College, Oxford OX1 4AU, UK; MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, Kensington, London SW7 2DD, UK
| | - Diego Gonzalez
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK; Calleva Research Centre for Evolution and Human Sciences, Magdalen College, Oxford OX1 4AU, UK
| | - Wook Kim
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - Stuart A West
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK; Calleva Research Centre for Evolution and Human Sciences, Magdalen College, Oxford OX1 4AU, UK
| | - Kevin R Foster
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK; Calleva Research Centre for Evolution and Human Sciences, Magdalen College, Oxford OX1 4AU, UK.
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15
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Johnstone RA, Rodrigues AMM. Cooperation and the common good. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150086. [PMID: 26729926 DOI: 10.1098/rstb.2015.0086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this paper, we draw the attention of biologists to a result from the economic literature, which suggests that when individuals are engaged in a communal activity of benefit to all, selection may favour cooperative sharing of resources even among non-relatives. Provided that group members all invest some resources in the public good, they should refrain from conflict over the division of these resources. The reason is that, given diminishing returns on investment in public and private goods, claiming (or ceding) a greater share of total resources only leads to the actor (or its competitors) investing more in the public good, such that the marginal costs and benefits of investment remain in balance. This cancels out any individual benefits of resource competition. We illustrate how this idea may be applied in the context of biparental care, using a sequential game in which parents first compete with one another over resources, and then choose how to allocate the resources they each obtain to care of their joint young (public good) versus their own survival and future reproductive success (private good). We show that when the two parents both invest in care to some extent, they should refrain from any conflict over the division of resources. The same effect can also support asymmetric outcomes in which one parent competes for resources and invests in care, whereas the other does not invest but refrains from competition. The fact that the caring parent gains higher fitness pay-offs at these equilibria suggests that abandoning a partner is not always to the latter's detriment, when the potential for resource competition is taken into account, but may instead be of benefit to the 'abandoned' mate.
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Affiliation(s)
- Rufus A Johnstone
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - António M M Rodrigues
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK Wolfson College, Barton Road, Cambridge CB3 9BB, UK
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Rodrigues AMM, Kokko H. Models of social evolution: can we do better to predict 'who helps whom to achieve what'? Philos Trans R Soc Lond B Biol Sci 2016; 371:20150088. [PMID: 26729928 DOI: 10.1098/rstb.2015.0088] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Models of social evolution and the evolution of helping have been classified in numerous ways. Two categorical differences have, however, escaped attention in the field. Models tend not to justify why they use a particular assumption structure about who helps whom: a large number of authors model peer-to-peer cooperation of essentially identical individuals, probably for reasons of mathematical convenience; others are inspired by particular cooperatively breeding species, and tend to assume unidirectional help where subordinates help a dominant breed more efficiently. Choices regarding what the help achieves (i.e. which life-history trait of the helped individual is improved) are similarly made without much comment: fecundity benefits are much more commonly modelled than survival enhancements, despite evidence that these may interact when the helped individual can perform life-history reallocations (load-lightening and related phenomena). We review our current theoretical understanding of effects revealed when explicitly asking 'who helps whom to achieve what', from models of mutual aid in partnerships to the very few models that explicitly contrast the strength of selection to help enhance another individual's fecundity or survival. As a result of idiosyncratic modelling choices in contemporary literature, including the varying degree to which demographic consequences are made explicit, there is surprisingly little agreement on what types of help are predicted to evolve most easily. We outline promising future directions to fill this gap.
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Affiliation(s)
- António M M Rodrigues
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK Wolfson College, Barton Road, Cambridge CB3 9BB, UK
| | - Hanna Kokko
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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17
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Leimar O, Dall SRX, Hammerstein P, McNamara JM. Genes as Cues of Relatedness and Social Evolution in Heterogeneous Environments. PLoS Comput Biol 2016; 12:e1005006. [PMID: 27341199 PMCID: PMC4920369 DOI: 10.1371/journal.pcbi.1005006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/27/2016] [Indexed: 12/23/2022] Open
Abstract
There are many situations where relatives interact while at the same time there is genetic polymorphism in traits influencing survival and reproduction. Examples include cheater-cooperator polymorphism and polymorphic microbial pathogens. Environmental heterogeneity, favoring different traits in nearby habitats, with dispersal between them, is one general reason to expect polymorphism. Currently, there is no formal framework of social evolution that encompasses genetic polymorphism. We develop such a framework, thus integrating theories of social evolution into the evolutionary ecology of heterogeneous environments. We allow for adaptively maintained genetic polymorphism by applying the concept of genetic cues. We analyze a model of social evolution in a two-habitat situation with limited dispersal between habitats, in which the average relatedness at the time of helping and other benefits of helping can differ between habitats. An important result from the analysis is that alleles at a polymorphic locus play the role of genetic cues, in the sense that the presence of a cue allele contains statistical information for an organism about its current environment, including information about relatedness. We show that epistatic modifiers of the cue polymorphism can evolve to make optimal use of the information in the genetic cue, in analogy with a Bayesian decision maker. Another important result is that the genetic linkage between a cue locus and modifier loci influences the evolutionary interest of modifiers, with tighter linkage leading to greater divergence between social traits induced by different cue alleles, and this can be understood in terms of genetic conflict. The theory of kin selection explains the evolution of helping when relatives interact. It can be used when individuals in a social group have different sexes, ages or phenotypic qualities, but the theory has not been worked out for situations where there is genetic polymorphism in helping. That kind of polymorphism, for instance cheater-cooperator polymorphism in microbes, has attracted much interest. We include these phenomena into a general framework of social evolution. Our framework is built on the idea of genetic cues, which means that an individual uses its genotype at a polymorphic locus as a statistical predictor of the current social conditions, including the expected relatedness in a social group. We allow for multilocus determination of the phenotype, in the form of modifiers of the effects of the alleles at a cue locus, and we find that there can be genetic conflicts between modifier loci that are tightly linked versus unlinked to the cue locus.
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Affiliation(s)
- Olof Leimar
- Department of Zoology, Stockholm University, Stockholm, Sweden
- * E-mail:
| | - Sasha R. X. Dall
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Peter Hammerstein
- Institute for Theoretical Biology, Humboldt University Berlin, Berlin, Germany
| | - John M. McNamara
- School of Mathematics, University of Bristol, Bristol, United Kingdom
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18
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Rodrigues AMM, Gardner A. Simultaneous failure of two sex-allocation invariants: implications for sex-ratio variation within and between populations. Proc Biol Sci 2016; 282:rspb.2015.0570. [PMID: 26085590 PMCID: PMC4590475 DOI: 10.1098/rspb.2015.0570] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Local mate competition (LMC) occurs when male relatives compete for mating opportunities, and this may favour the evolution of female-biased sex allocation. LMC theory is among the most well developed and empirically supported topics in behavioural ecology, clarifies links between kin selection, group selection and game theory, and provides among the best quantitative evidence for Darwinian adaptation in the natural world. Two striking invariants arise from this body of work: the number of sons produced by each female is independent of both female fecundity and also the rate of female dispersal. Both of these invariants have stimulated a great deal of theoretical and empirical research. Here, we show that both of these invariants break down when variation in female fecundity and limited female dispersal are considered in conjunction. Specifically, limited dispersal of females following mating leads to local resource competition (LRC) between female relatives for breeding opportunities, and the daughters of high-fecundity mothers experience such LRC more strongly than do those of low-fecundity mothers. Accordingly, high-fecundity mothers are favoured to invest relatively more in sons, while low-fecundity mothers are favoured to invest relatively more in daughters, and the overall sex ratio of the population sex ratio becomes more female biased as a result.
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Affiliation(s)
- António M M Rodrigues
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK Wolfson College, Barton Road, Cambridge CB3 9BB, UK
| | - Andy Gardner
- School of Biology, University of St Andrews, Dyers Brae, St Andrews KY16 9TH, UK
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19
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Barker JL, Loope KJ, Reeve HK. Asymmetry within social groups: division of labour and intergroup competition. J Evol Biol 2015; 29:560-71. [PMID: 26663312 PMCID: PMC4784174 DOI: 10.1111/jeb.12805] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 10/22/2015] [Accepted: 12/01/2015] [Indexed: 11/28/2022]
Abstract
Social animals vary in their ability to compete with group members over shared resources and also vary in their cooperative efforts to produce these resources. Competition among groups can promote within-group cooperation, but many existing models of intergroup cooperation do not explicitly account for observations that group members invest differentially in cooperation and that there are often within-group competitive or power asymmetries. We present a game theoretic model of intergroup competition that investigates how such asymmetries affect within-group cooperation. In this model, group members adopt one of two roles, with relative competitive efficiency and the number of individuals varying between roles. Players in each role make simultaneous, coevolving decisions. The model predicts that although intergroup competition increases cooperative contributions to group resources by both roles, contributions are predominantly from individuals in the less competitively efficient role, whereas individuals in the more competitively efficient role generally gain the larger share of these resources. When asymmetry in relative competitive efficiency is greater, a group's per capita cooperation (averaged across both roles) is higher, due to increased cooperation from the competitively inferior individuals. For extreme asymmetry in relative competitive efficiency, per capita cooperation is highest in groups with a single competitively superior individual and many competitively inferior individuals, because the latter acquiesce and invest in cooperation rather than within-group competition. These predictions are consistent with observed features of many societies, such as monogynous Hymenoptera with many workers and caste dimorphism.
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Affiliation(s)
- J L Barker
- Department of Neurobiology & Behavior, Cornell University, Ithaca, NY, USA
| | - K J Loope
- Department of Neurobiology & Behavior, Cornell University, Ithaca, NY, USA
| | - H K Reeve
- Department of Neurobiology & Behavior, Cornell University, Ithaca, NY, USA
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20
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Rodrigues AMM, Gardner A. The constant philopater hypothesis: a new life history invariant for dispersal evolution. J Evol Biol 2015; 29:153-66. [PMID: 26431821 PMCID: PMC4738439 DOI: 10.1111/jeb.12771] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/25/2015] [Accepted: 09/28/2015] [Indexed: 11/29/2022]
Abstract
Surprising invariance relationships have emerged from the study of social interaction, whereby a cancelling‐out of multiple partial effects of genetic, ecological or demographic parameters means that they have no net impact upon the evolution of a social behaviour. Such invariants play a pivotal role in the study of social adaptation: on the one hand, they provide theoretical hypotheses that can be empirically tested; and, on the other hand, they provide benchmark frameworks against which new theoretical developments can be understood. Here we derive a novel invariant for dispersal evolution: the ‘constant philopater hypothesis’ (CPH). Specifically, we find that, irrespective of variation in maternal fecundity, all mothers are favoured to produce exactly the same number of philopatric offspring, with high‐fecundity mothers investing proportionally more, and low‐fecundity mothers investing proportionally less, into dispersing offspring. This result holds for female and male dispersal, under haploid, diploid and haplodiploid modes of inheritance, irrespective of the sex ratio, local resource availability and whether mother or offspring controls the latter's dispersal propensity. We explore the implications of this result for evolutionary conflict of interests – and the exchange and withholding of contextual information – both within and between families, and we show that the CPH is the fundamental invariant that underpins and explains a wider family of invariance relationships that emerge from the study of social evolution.
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Affiliation(s)
- A M M Rodrigues
- Department of Zoology, University of Cambridge, Cambridge, UK.,Wolfson College, Cambridge, UK
| | - A Gardner
- School of Biology, University of St Andrews, St Andrews, UK
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21
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Faria GS, Varela SAM, Gardner A. Sex-biased dispersal, kin selection and the evolution of sexual conflict. J Evol Biol 2015; 28:1901-10. [PMID: 26190034 DOI: 10.1111/jeb.12697] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 12/01/2022]
Abstract
There is growing interest in resolving the curious disconnect between the fields of kin selection and sexual selection. Rankin's (2011, J. Evol. Biol. 24, 71-81) theoretical study of the impact of kin selection on the evolution of sexual conflict in viscous populations has been particularly valuable in stimulating empirical research in this area. An important goal of that study was to understand the impact of sex-specific rates of dispersal upon the coevolution of male-harm and female-resistance behaviours. But the fitness functions derived in Rankin's study do not flow from his model's assumptions and, in particular, are not consistent with sex-biased dispersal. Here, we develop new fitness functions that do logically flow from the model's assumptions, to determine the impact of sex-specific patterns of dispersal on the evolution of sexual conflict. Although Rankin's study suggested that increasing male dispersal always promotes the evolution of male harm and that increasing female dispersal always inhibits the evolution of male harm, we find that the opposite can also be true, depending upon parameter values.
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Affiliation(s)
- Gonçalo S Faria
- cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Susana A M Varela
- cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Andy Gardner
- School of Biology, University of St Andrews, St Andrews, UK
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22
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Peña J, Nöldeke G, Lehmann L. Evolutionary dynamics of collective action in spatially structured populations. J Theor Biol 2015; 382:122-36. [PMID: 26151588 DOI: 10.1016/j.jtbi.2015.06.039] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/22/2015] [Accepted: 06/24/2015] [Indexed: 01/09/2023]
Abstract
Many models proposed to study the evolution of collective action rely on a formalism that represents social interactions as n-player games between individuals adopting discrete actions such as cooperate and defect. Despite the importance of spatial structure in biological collective action, the analysis of n-player games games in spatially structured populations has so far proved elusive. We address this problem by considering mixed strategies and by integrating discrete-action n-player games into the direct fitness approach of social evolution theory. This allows to conveniently identify convergence stable strategies and to capture the effect of population structure by a single structure coefficient, namely, the pairwise (scaled) relatedness among interacting individuals. As an application, we use our mathematical framework to investigate collective action problems associated with the provision of three different kinds of collective goods, paradigmatic of a vast array of helping traits in nature: "public goods" (both providers and shirkers can use the good, e.g., alarm calls), "club goods" (only providers can use the good, e.g., participation in collective hunting), and "charity goods" (only shirkers can use the good, e.g., altruistic sacrifice). We show that relatedness promotes the evolution of collective action in different ways depending on the kind of collective good and its economies of scale. Our findings highlight the importance of explicitly accounting for relatedness, the kind of collective good, and the economies of scale in theoretical and empirical studies of the evolution of collective action.
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Affiliation(s)
- Jorge Peña
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany.
| | - Georg Nöldeke
- Faculty of Business and Economics, University of Basel, Peter Merian-Weg 6, 4002 Basel, Switzerland.
| | - Laurent Lehmann
- Department of Ecology and Evolution, University of Lausanne, Le Biophore, 1015 Lausanne, Switzerland.
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