1
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Scott TW. Crozier's paradox and kin recognition: Insights from simplified models. J Theor Biol 2024; 581:111735. [PMID: 38246487 DOI: 10.1016/j.jtbi.2024.111735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/19/2023] [Accepted: 01/12/2024] [Indexed: 01/23/2024]
Abstract
Crozier's paradox suggests that genetic kin recognition will not be evolutionarily stable. The problem is that more common tags (markers) are more likely to be recognised and helped. This causes common tags to increase in frequency, eliminating the genetic variability that is required for genetic kin recognition. In recent years, theoretical models have resolved Crozier's paradox in different ways, but they are based on very complicated multi-locus population genetics. Consequently, it is hard to see exactly what is going on, and whether different theoretical resolutions of Crozier's paradox lead to different types of kin discrimination. I address this by making unrealistic simplifying assumptions to produce a more tractable and understandable model of Crozier's paradox. I use this to interpret a more complex multi-locus population genetic model where I have not made the same simplifying assumptions. I explain how Crozier's paradox can be resolved, and show that only one known theoretical resolution of Crozier's paradox - multiple social encounters - leads without restrictive assumptions to the type of highly cooperative and reliable form of kin discrimination that we observe in nature. More generally, I show how adopting a methodological approach where complex models are compared with simplified ones can lead to greater understanding and accessibility.
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Affiliation(s)
- Thomas W Scott
- Department of Biology, University of Oxford, Oxford OX1 3SZ, United Kingdom.
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2
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Scott TW, Wild G. How to make an inclusive-fitness model. Proc Biol Sci 2023; 290:20231310. [PMID: 37788701 PMCID: PMC10547548 DOI: 10.1098/rspb.2023.1310] [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: 06/12/2023] [Accepted: 09/05/2023] [Indexed: 10/05/2023] Open
Abstract
Social behaviours are typically modelled using neighbour-modulated fitness, which focuses on individuals having their fitness altered by neighbours. However, these models are either interpreted using inclusive fitness, which focuses on individuals altering the fitness of neighbours, or not interpreted at all. This disconnect leads to interpretational mistakes and obscures the adaptive significance of behaviour. We bridge this gap by presenting a systematic methodology for constructing inclusive-fitness models. We find a behaviour's 'inclusive-fitness effect' by summing primary and secondary deviations in reproductive value. Primary deviations are the immediate result of a social interaction; for example, the cost and benefit of an altruistic act. Secondary deviations are compensatory effects that arise because the total reproductive value of the population is fixed; for example, the increased competition that follows an altruistic act. Compared to neighbour-modulated fitness methodologies, our approach is often simpler and reveals the model's inclusive-fitness narrative clearly. We implement our methodology first in a homogeneous population, with supplementary examples of help under synergy, help in a viscous population and Creel's paradox. We then implement our methodology in a class-structured population, where the advantages of our approach are most evident, with supplementary examples of altruism between age classes, and sex-ratio evolution.
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Affiliation(s)
- Thomas W. Scott
- Department of Biology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Geoff Wild
- Department of Mathematics, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7
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3
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Scott TW, Grafen A, West SA. Host-parasite coevolution and the stability of genetic kin recognition. Proc Natl Acad Sci U S A 2023; 120:e2220761120. [PMID: 37463213 PMCID: PMC10372634 DOI: 10.1073/pnas.2220761120] [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: 12/07/2022] [Accepted: 05/26/2023] [Indexed: 07/20/2023] Open
Abstract
Crozier's paradox suggests that genetic kin recognition will not be evolutionarily stable. The problem is that more common tags (markers) are more likely to be recognized and helped. This causes common tags to increase in frequency, eliminating the genetic variability that is required for genetic kin recognition. Two potential solutions to this problem have been suggested: host-parasite coevolution and multiple social encounters. We show that the host-parasite coevolution hypothesis does not work as commonly assumed. Host-parasite coevolution only stabilizes kin recognition at a parasite resistance locus if parasites adapt rapidly to hosts and cause intermediate or high levels of damage (virulence). Additionally, when kin recognition is stabilized at a parasite resistance locus, this can have an additional cost of making hosts more susceptible to parasites. However, we show that if the genetic architecture is allowed to evolve, meaning natural selection can choose the recognition locus, genetic kin recognition is more likely to be stable. The reason for this is that host-parasite coevolution can maintain tag diversity at another (neutral) locus by genetic hitchhiking, allowing that other locus to be used for genetic kin recognition. These results suggest a way that host-parasite coevolution can resolve Crozier's paradox, without making hosts more susceptible to parasites. However, the opportunity for multiple social encounters may provide a more robust resolution of Crozier's paradox.
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Affiliation(s)
- Thomas W. Scott
- Department of Biology, University of Oxford, OxfordOX1 3SZ, United Kingdom
| | - Alan Grafen
- Department of Biology, University of Oxford, OxfordOX1 3SZ, United Kingdom
| | - Stuart A. West
- Department of Biology, University of Oxford, OxfordOX1 3SZ, United Kingdom
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4
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Van Cleve J. Evolutionarily stable strategy analysis and its links to demography and genetics through invasion fitness. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210496. [PMID: 36934754 PMCID: PMC10024993 DOI: 10.1098/rstb.2021.0496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/07/2023] [Indexed: 03/21/2023] Open
Abstract
Evolutionarily stable strategy (ESS) analysis pioneered by Maynard Smith and Price took off in part because it often does not require explicit assumptions about the genetics and demography of a population in contrast to population genetic models. Though this simplicity is useful, it obscures the degree to which ESS analysis applies to populations with more realistic genetics and demography: for example, how does ESS analysis handle complexities such as kin selection, group selection and variable environments when phenotypes are affected by multiple genes? In this paper, I review the history of the ESS concept and show how early uncertainty about the method lead to important mathematical theory linking ESS analysis to general population genetic models. I use this theory to emphasize the link between ESS analysis and the concept of invasion fitness. I give examples of how invasion fitness can measure kin selection, group selection and the evolution of linked modifier genes in response to variable environments. The ESSs in these examples depend crucially on demographic and genetic parameters, which highlights how ESS analysis will continue to be an important tool in understanding evolutionary patterns as new models address the increasing abundance of genetic and long-term demographic data in natural populations. 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)
- Jeremy Van Cleve
- Department of Biology, University of Kentucky, Lexington, KY 40506 USA
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5
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Liu M, West SA, Wild G. The evolution of manipulative cheating. eLife 2022; 11:e80611. [PMID: 36193888 PMCID: PMC9633066 DOI: 10.7554/elife.80611] [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: 05/27/2022] [Accepted: 10/03/2022] [Indexed: 01/07/2023] Open
Abstract
A social cheat is typically assumed to be an individual that does not perform a cooperative behaviour, or performs less of it, but can still exploit the cooperative behaviour of others. However, empirical data suggests that cheating can be more subtle, involving evolutionary arms races over the ability to both exploit and resist exploitation. These complications have not been captured by evolutionary theory, which lags behind empirical studies in this area. We bridge this gap with a mixture of game-theoretical models and individual-based simulations, examining what conditions favour more elaborate patterns of cheating. We found that as well as adjusting their own behaviour, individuals can be selected to manipulate the behaviour of others, which we term 'manipulative cheating'. Further, we found that manipulative cheating can lead to dynamic oscillations (arms races), between selfishness, manipulation, and suppression of manipulation. Our results can help explain both variation in the level of cheating, and genetic variation in the extent to which individuals can be exploited by cheats.
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Affiliation(s)
- Ming Liu
- Department of Biology, University of OxfordOxfordUnited Kingdom
| | | | - Geoff Wild
- Department of Mathematics, The University of Western OntarioLondonCanada
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6
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Scott TW, Grafen A, West SA. Multiple social encounters can eliminate Crozier's paradox and stabilise genetic kin recognition. Nat Commun 2022; 13:3902. [PMID: 35794146 PMCID: PMC9259605 DOI: 10.1038/s41467-022-31545-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 06/22/2022] [Indexed: 11/28/2022] Open
Abstract
Crozier's paradox suggests that genetic kin recognition will not be evolutionarily stable. The problem is that more common tags (markers) are more likely to be recognised and helped. This causes common tags to increase in frequency, and hence eliminates the genetic variability that is required for genetic kin recognition. It has therefore been assumed that genetic kin recognition can only be stable if there is some other factor maintaining tag diversity, such as the advantage of rare alleles in host-parasite interactions. We show that allowing for multiple social encounters before each social interaction can eliminate Crozier's paradox, because it allows individuals with rare tags to find others with the same tag. We also show that rare tags are better indicators of relatedness, and hence better at helping individuals avoid interactions with non-cooperative cheats. Consequently, genetic kin recognition provides an advantage to rare tags that maintains tag diversity, and stabilises itself.
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Affiliation(s)
- Thomas W Scott
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK.
| | - Alan Grafen
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK
| | - Stuart A West
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK
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7
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Koliofotis V, Verreault-Julien P. Hamilton's rule: A non-causal explanation? STUDIES IN HISTORY AND PHILOSOPHY OF SCIENCE 2022; 92:109-118. [PMID: 35158172 DOI: 10.1016/j.shpsa.2021.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 10/26/2021] [Accepted: 11/16/2021] [Indexed: 06/14/2023]
Abstract
The explanatory power of Hamilton's rule, the main explanatory principle of social evolution theory, is an ongoing subject of controversy. In this paper, we reinforce the case for the considerable value of the regression-based version of the rule in explaining the evolution of social traits. Although we agree that the rule can have an organizing role in social evolution research, we maintain that it does not explain in virtue of citing causes or providing an organizing framework. Instead, we argue it either provides an explanation by constraint or a non-causal counterfactual explanation.
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8
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Takeuchi N, Mitarai N, Kaneko K. A scaling law of multilevel evolution: how the balance between within- and among-collective evolution is determined. Genetics 2021; 220:6409194. [PMID: 34849893 PMCID: PMC9208640 DOI: 10.1093/genetics/iyab182] [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: 03/30/2021] [Accepted: 10/15/2021] [Indexed: 11/14/2022] Open
Abstract
Numerous living systems are hierarchically organised, whereby replicating components are grouped into reproducing collectives-e.g., organelles are grouped into cells, and cells are grouped into multicellular organisms. In such systems, evolution can operate at two levels: evolution among collectives, which tends to promote selfless cooperation among components within collectives (called altruism), and evolution within collectives, which tends to promote cheating among components within collectives. The balance between within- and among-collective evolution thus exerts profound impacts on the fitness of these systems. Here, we investigate how this balance depends on the size of a collective (denoted by N) and the mutation rate of components (m) through mathematical analyses and computer simulations of multiple population genetics models. We first confirm a previous result that increasing N or m accelerates within-collective evolution relative to among-collective evolution, thus promoting the evolution of cheating. Moreover, we show that when within- and among-collective evolution exactly balance each other out, the following scaling relation generally holds: Nmα is a constant, where scaling exponent α depends on multiple parameters, such as the strength of selection and whether altruism is a binary or quantitative trait. This relation indicates that although N and m have quantitatively distinct impacts on the balance between within- and among-collective evolution, their impacts become identical if m is scaled with a proper exponent. Our results thus provide a novel insight into conditions under which cheating or altruism evolves in hierarchically-organised replicating systems.
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Affiliation(s)
- Nobuto Takeuchi
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
- Research Center for Complex Systems Biology, Universal Biology Institute, University of Tokyo, Tokyo 153-8902, Japan
- Corresponding author: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Namiko Mitarai
- Research Center for Complex Systems Biology, Universal Biology Institute, University of Tokyo, Tokyo 153-8902, Japan
- The Niels Bohr Institute, University of Copenhagen, Copenhagen 2100-DK, Denmark
| | - Kunihiko Kaneko
- Research Center for Complex Systems Biology, Universal Biology Institute, University of Tokyo, Tokyo 153-8902, Japan
- Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan
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9
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Smith J, Inglis RF. Evaluating kin and group selection as tools for quantitative analysis of microbial data. Proc Biol Sci 2021; 288:20201657. [PMID: 34004128 PMCID: PMC8131122 DOI: 10.1098/rspb.2020.1657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/22/2021] [Indexed: 11/26/2022] Open
Abstract
Kin selection and multilevel selection theory are often used to interpret experiments about the evolution of cooperation and social behaviour among microbes. But while these experiments provide rich, detailed fitness data, theory is mostly used as a conceptual heuristic. Here, we evaluate how kin and multilevel selection theory perform as quantitative analysis tools. We reanalyse published microbial datasets and show that the canonical fitness models of both theories are almost always poor fits because they use statistical regressions misspecified for the strong selection and non-additive effects we show are widespread in microbial systems. We identify analytical practices in empirical research that suggest how theory might be improved, and show that analysing both individual and group fitness outcomes helps clarify the biology of selection. A data-driven approach to theory thus shows how kin and multilevel selection both have untapped potential as tools for quantitative understanding of social evolution in all branches of life.
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Affiliation(s)
- Jeff Smith
- Department of Biology, University of Missouri–St Louis, St Louis MO 63121, USA
| | - R. Fredrik Inglis
- Department of Biology, University of Missouri–St Louis, St Louis MO 63121, USA
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10
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Araya‐Ajoy YG, Westneat DF, Wright J. Pathways to social evolution and their evolutionary feedbacks. Evolution 2020; 74:1894-1907. [DOI: 10.1111/evo.14054] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 05/23/2020] [Accepted: 06/27/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Yimen G. Araya‐Ajoy
- Centre for Biodiversity Dynamics (CBD), Department of Biology Norwegian University of Science and Technology (NTNU) Trondheim N‐7491 Norway
| | - David F. Westneat
- Department of Biology, 101 Morgan Building University of Kentucky Lexington KY 40506‐0225 USA
| | - Jonathan Wright
- Centre for Biodiversity Dynamics (CBD), Department of Biology Norwegian University of Science and Technology (NTNU) Trondheim N‐7491 Norway
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11
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Van Cleve J. Building a synthetic basis for kin selection and evolutionary game theory using population genetics. Theor Popul Biol 2020; 133:65-70. [PMID: 32165158 DOI: 10.1016/j.tpb.2020.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Jeremy Van Cleve
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
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12
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Queller DC. The gene's eye view, the Gouldian knot, Fisherian swords and the causes of selection. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190354. [PMID: 32146882 DOI: 10.1098/rstb.2019.0354] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The biological units-of-selection debate has centred on questions of which units experience selection and adaptation. Here, I use a causal framework and the Price equation to develop the gene's eye perspective. Genes are causally special in being both replicators and interactors. Gene effects are tied together in a complex Gouldian knot of interactions, but Fisher deployed three swords to try to cut the knot. The first, Fisher's average excess, is non-causal, so not fully satisfactory in that respect. The Price equation highlights Fisher's other two swords, choosing to model only selection, and only the part that is transmissible across generations. The models developed here show that many causes of organismal fitness do not cause Gouldian complications. Only two kinds of elements must be added to the focal gene for a causal explanation of its selective change: co-replicators that are associated with the focal gene and co-interactors that interact non-additively with the focal gene. Identical equations for co-replication and co-interaction describe interactions between gene copies at a single locus or at separate loci, and also for genes situated within the same individual or in different individuals. These results resolve some of the objections to the gene's eye view. This article is part of the theme issue 'Fifty years of the Price equation'.
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Affiliation(s)
- David C Queller
- Department of Biology, Washington University in St Louis, St Louis, MO 63105, USA.,Wissenschaftskolleg zu Berlin, 14193 Berlin, Germany
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13
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Rice SH. Universal rules for the interaction of selection and transmission in evolution. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190353. [PMID: 32146884 DOI: 10.1098/rstb.2019.0353] [Citation(s) in RCA: 4] [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
The Price equation shows that evolutionary change can be written in terms of two fundamental variables: the fitness of parents (or ancestors) and the phenotypes of their offspring (descendants). Its power lies in the fact that it requires no simplifying assumptions other than a closed population, but realizing the full potential of Price's result requires that we flesh out the mathematical representation of both fitness and offspring phenotype. Specifically, both need to be treated as stochastic variables that are themselves functions of parental phenotype. Here, I show how new mathematical tools allow us to do this without introducing any simplifying assumptions. Combining this representation of fitness and phenotype with the stochastic Price equation reveals fundamental rules underlying multivariate evolution and the evolution of inheritance. Finally, I show how the change in the entire phenotype distribution of a population, not simply the mean phenotype, can be written as a single compact equation from which the Price equation and related results can be derived as special cases. This article is part of the theme issue 'Fifty years of the Price equation'.
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Affiliation(s)
- Sean H Rice
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
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14
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Akçay E. Deconstructing Evolutionary Game Theory: Coevolution of Social Behaviors with Their Evolutionary Setting. Am Nat 2019; 195:315-330. [PMID: 32017621 DOI: 10.1086/706811] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Evolution of social behaviors is one of the most fascinating and active fields of evolutionary biology. During the past half century, social evolution theory developed into a mature field with powerful tools to understand the dynamics of social traits such as cooperation under a wide range of conditions. In this article, I argue that the next stage in the development of social evolution theory should consider the evolution of the setting in which social behaviors evolve. To that end, I propose a conceptual map of the components that make up the evolutionary setting of social behaviors, review existing work that considers the evolution of each component, and discuss potential future directions. The theoretical work reviewed here illustrates how unexpected dynamics can happen when the setting of social evolution itself is evolving, such as cooperation sometimes being self-limiting. I argue that a theory of how the setting of social evolution itself evolves will lead to a deeper understanding of when cooperation and other social behaviors evolve and diversify.
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15
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Levin SR, Gandon S, West SA. The social coevolution hypothesis for the origin of enzymatic cooperation. Nat Ecol Evol 2019; 4:132-137. [PMID: 31844190 DOI: 10.1038/s41559-019-1039-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 10/15/2019] [Indexed: 11/09/2022]
Abstract
At the start of life, the origin of a primitive genome required individual replicators, or genes, to act like enzymes and cooperatively copy each other. The evolutionary stability of such enzymatic cooperation poses a problem, because it would have been susceptible to parasitic replicators that did not act like enzymes but could still benefit from the enzymatic behaviour of other replicators. Existing hypotheses to solve this problem require restrictive assumptions that may not be justified, such as the evolution of a cell membrane before the evolution of enzymatic cooperation. We show theoretically that, instead, selection itself can lead to replicators grouping themselves together in a way that favours cooperation. We show that the tendency to physically associate with others and cooperative enzymatic activity can coevolve, leading to the evolution of physically linked cooperative replicators. Our results shift the empirical problem from a search for special environmental conditions to questions about what types of phenotypes can be produced by simple replicators.
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Affiliation(s)
- Samuel R Levin
- Department of Zoology, University of Oxford, Oxford, UK.
| | - Sylvain Gandon
- CEFE UMR 5175, CNRS, Université de Montpellier, Montpellier, France
| | - Stuart A West
- Department of Zoology, University of Oxford, Oxford, UK
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16
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Davies NG, Gardner A. Monogamy promotes altruistic sterility in insect societies. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172190. [PMID: 29892408 PMCID: PMC5990772 DOI: 10.1098/rsos.172190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/03/2018] [Indexed: 06/08/2023]
Abstract
Monogamy is associated with sibling-directed altruism in multiple animal taxa, including insects, birds and mammals. Inclusive-fitness theory readily explains this pattern by identifying high relatedness as a promoter of altruism. In keeping with this prediction, monogamy should promote the evolution of voluntary sterility in insect societies if sterile workers make for better helpers. However, a recent mathematical population-genetics analysis failed to identify a consistent effect of monogamy on voluntary worker sterility. Here, we revisit that analysis. First, we relax genetic assumptions, considering not only alleles of extreme effect-encoding either no sterility or complete sterility-but also alleles with intermediate effects on worker sterility. Second, we broaden the stability analysis-which focused on the invasibility of populations where either all workers are fully sterile or all workers are fully reproductive-to identify where intermediate pure or mixed evolutionarily stable states may occur. Third, we consider a broader range of demographically explicit ecological scenarios relevant to altruistic worker non-reproduction and to the evolution of eusociality more generally. We find that, in the absence of genetic constraints, monogamy always promotes altruistic worker sterility and may inhibit spiteful worker sterility. Our extended analysis demonstrates that an exact population-genetics approach strongly supports the prediction of inclusive-fitness theory that monogamy promotes sib-directed altruism in social insects.
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Affiliation(s)
| | - Andy Gardner
- School of Biology, University of St Andrews, St Andrews, UK
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17
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Birch J. The inclusive fitness controversy: finding a way forward. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170335. [PMID: 28791162 PMCID: PMC5541557 DOI: 10.1098/rsos.170335] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
This paper attempts to reconcile critics and defenders of inclusive fitness by constructing a synthesis that does justice to the insights of both. I argue that criticisms of the regression-based version of Hamilton's rule, although they undermine its use for predictive purposes, do not undermine its use as an organizing framework for social evolution research. I argue that the assumptions underlying the concept of inclusive fitness, conceived as a causal property of an individual organism, are unlikely to be exactly true in real populations, but they are approximately true given a specific type of weak selection that Hamilton took, on independent grounds, to be responsible for the cumulative assembly of complex adaptation. Finally, I reflect on the uses and limitations of 'design thinking' in social evolution research.
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Affiliation(s)
- Jonathan Birch
- Department of Philosophy, Logic and Scientific Method, London School of Economics and Political Science, Houghton Street, London, WC2A 2AE, UK
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18
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Schuster M, Sexton DJ, Hense BA. Why Quorum Sensing Controls Private Goods. Front Microbiol 2017; 8:885. [PMID: 28579979 PMCID: PMC5437708 DOI: 10.3389/fmicb.2017.00885] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/02/2017] [Indexed: 12/22/2022] Open
Abstract
Cell-cell communication, also termed quorum sensing (QS), is a widespread process that coordinates gene expression in bacterial populations. The generally accepted view is that QS optimizes the cell density-dependent benefit attained from cooperative behaviors, often in the form of secreted products referred to as "public goods." This view is challenged by an increasing number of cell-associated products or "private goods" reported to be under QS-control for which a collective benefit is not apparent. A prominent example is nucleoside hydrolase from Pseudomonas aeruginosa, a periplasmic enzyme that catabolizes adenosine. Several recent studies have shown that private goods can function to stabilize cooperation by co-regulated public goods, seemingly explaining their control by QS. Here we argue that this property is a by-product of selection for other benefits rather than an adaptation. Emphasizing ecophysiological context, we propose alternative explanations for the QS control of private goods. We suggest that the benefit attained from private goods is associated with high cell density, either because a relevant ecological condition correlates with density, or because the private good is, directly or indirectly, involved in cooperative behavior. Our analysis helps guide a systems approach to QS, with implications for antivirulence drug design and synthetic biology.
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Affiliation(s)
- Martin Schuster
- Department of Microbiology, Oregon State UniversityCorvallis, OR, United States
| | - D Joseph Sexton
- Department of Microbiology, Oregon State UniversityCorvallis, OR, United States
| | - Burkhard A Hense
- Institute of Computational Biology, Helmholtz Zentrum MünchenNeuherberg, Germany
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19
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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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20
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Van Cleve J. Cooperation, conformity, and the coevolutionary problem of trait associations. J Theor Biol 2016; 396:13-24. [PMID: 26907203 DOI: 10.1016/j.jtbi.2016.02.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 01/24/2016] [Accepted: 02/10/2016] [Indexed: 11/29/2022]
Abstract
In large scale social systems, coordinated or cooperative outcomes become difficult because encounters between kin or repeated encounters between friends are infrequent. Even punishment of noncooperators does not entirely alleviate the dilemma. One important mechanism for achieving cooperative outcomes in such social systems is conformist bias where individuals copy the behavior performed by the majority of their group mates. Conformist bias enhances group competition by both stabilizing behaviors within groups and increasing variance between groups. Due to this group competition effect, conformist bias is thought to have been an important driver of human social complexity and cultural diversity. However, conformist bias only evolves indirectly through associations with other traits, and I show that such associations are more difficult to obtain than previously expected. Specifically, I show that initial measures of population structure must be strong in order for a strong association between conformist bias and cooperative behaviors (cooperation and costly punishment) to evolve and for these traits to reach high frequencies. Additionally, the required initial level of association does not evolve de novo in simulations run over long timescales. This suggests that the coevolution of cooperative behaviors and conformist bias alone may not explain the high levels of cooperation within human groups, though conformist bias may still play an important role in combination with other social and demographic forces.
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Affiliation(s)
- Jeremy Van Cleve
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
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21
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Abstract
Kin selection and multilevel selection are two major frameworks in evolutionary biology that aim at explaining the evolution of social behaviors. However, the relationship between these two theories has been plagued by controversy for almost half a century and debates about their relevance and usefulness in explaining social evolution seem to rekindle at regular intervals. Here, we first provide a concise introduction into the kin selection and multilevel selection theories and shed light onto the roots of the controversy surrounding them. We then review two major aspects of the current debate: the presumed formal equivalency of the two theories and the question whether group selection can lead to group adaptation. We conclude by arguing that the two theories can offer complementary approaches to the study of social evolution: kin selection approaches usually focus on the identification of optimal phenotypes and thus on the endresult of a selection process, whereas multilevel selection approaches focus on the ongoing selection process itself. The two theories thus provide different perspectives that might be fruitfully combined to promote our understanding of the evolution in group-structured populations.
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Affiliation(s)
- Jos Kramer
- Zoological Institute, Evolutionary Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Joël Meunier
- Zoological Institute, Evolutionary Biology, Johannes Gutenberg University Mainz, Mainz, Germany; Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS, Université François Rabelais, Tours, France
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22
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Metzler D, Jordan F, Pamminger T, Foitzik S. The influence of space and time on the evolution of altruistic defence: the case of ant slave rebellion. J Evol Biol 2016; 29:874-86. [PMID: 26873305 DOI: 10.1111/jeb.12846] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 01/21/2016] [Accepted: 02/06/2016] [Indexed: 11/29/2022]
Abstract
How can antiparasite defence traits evolve even if they do not directly benefit their carriers? An example of such an indirect defence is rebellion of enslaved Temnothorax longispinosus ant workers against their social parasite Temnothorax americanus, a slavemaking ant. Ant slaves have been observed to kill their oppressors' offspring, a behaviour from which the sterile slaves cannot profit directly. Parasite brood killing could, however, reduce raiding pressure on related host colonies nearby. We analyse with extensive computer simulations for the Temnothorax slavemaker system under what conditions a hypothetical rebel allele could invade a host population, and in particular, how host-parasite dynamics and population structure influence the rebel allele's success. Exploring a wide range of model parameters, we only found a small number of parameter combinations for which kin selection or multilevel selection could allow a slave rebellion allele to spread in the host population. Furthermore, we did not detect any cases in which the reduction of raiding pressure in the close vicinity of the slavemaker nest would substantially contribute to the inclusive fitness of rebels. This suggests that slave rebellion is not costly and perhaps a side-effect of some other beneficial trait. In some of our simulations, however, even a costly rebellion allele could spread in the population. This was possible when host-parasite interactions led to a metapopulation dynamic with frequent local extinctions and recolonizations of demes by the offspring of few immigrants.
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Affiliation(s)
- D Metzler
- Department of Biology, Ludwig-Maximilians-Universität München, München, Germany
| | - F Jordan
- Department of Biology, Ludwig-Maximilians-Universität München, München, Germany
| | - T Pamminger
- School of Life Science, University of Sussex, Brighton, UK
| | - S Foitzik
- Zoological Institute, Johannes Gutenberg University Mainz, Mainz, Germany
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23
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Okasha S, Martens J. The causal meaning of Hamilton's rule. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160037. [PMID: 27069669 PMCID: PMC4821280 DOI: 10.1098/rsos.160037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/16/2016] [Indexed: 06/05/2023]
Abstract
Hamilton's original derivation of his rule for the spread of an altruistic gene (rb>c) assumed additivity of costs and benefits. Recently, it has been argued that an exact version of the rule holds under non-additive pay-offs, so long as the cost and benefit terms are suitably defined, as partial regression coefficients. However, critics have questioned both the biological significance and the causal meaning of the resulting rule. This paper examines the causal meaning of the generalized Hamilton's rule in a simple model, by computing the effect of a hypothetical experiment to assess the cost of a social action and comparing it to the partial regression definition. The two do not agree. A possible way of salvaging the causal meaning of Hamilton's rule is explored, by appeal to R. A. Fisher's 'average effect of a gene substitution'.
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Affiliation(s)
- Samir Okasha
- Department of Philosophy, Cotham House, University of Bristol, Bristol BS6 6JL, UK
| | - Johannes Martens
- Institute for the History and Philosophy of Science and Technology, University of Paris-Sorbonne, Paris, France
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24
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Okasha S, Martens J. Hamilton's rule, inclusive fitness maximization, and the goal of individual behaviour in symmetric two-player games. J Evol Biol 2016; 29:473-82. [PMID: 26679493 DOI: 10.1111/jeb.12808] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 11/30/2015] [Accepted: 12/03/2015] [Indexed: 11/25/2022]
Abstract
Hamilton's original work on inclusive fitness theory assumed additivity of costs and benefits. Recently, it has been argued that an exact version of Hamilton's rule for the spread of a pro-social allele (rb > c) holds under nonadditive pay-offs, so long as the cost and benefit terms are defined as partial regression coefficients rather than pay-off parameters. This article examines whether one of the key components of Hamilton's original theory can be preserved when the rule is generalized to the nonadditive case in this way, namely that evolved organisms will behave as if trying to maximize their inclusive fitness in social encounters.
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Affiliation(s)
- S Okasha
- Department of Philosophy, University of Bristol, Bristol, UK
| | - J Martens
- Department of Philosophy, University of Bristol, Bristol, UK
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25
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Rousset F. Regression, least squares, and the general version of inclusive fitness. Evolution 2015; 69:2963-70. [PMID: 26454155 DOI: 10.1111/evo.12791] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/01/2015] [Indexed: 11/29/2022]
Abstract
A general version of inclusive fitness based on regression is rederived with minimal mathematics and directly from the verbal interpretation of its terms that motivated the original formulation of the inclusive fitness concept. This verbal interpretation is here extended to provide the two relationships required to determine the two coefficients -c and b. These coefficients retain their definition as expected effects on the fitness of an individual, respectively of a change in allelic state of this individual, and of correlated change in allelic state of social partners. The known least-squares formulation of the relationships determining b and c can be immediately deduced and shown to be equivalent to this new formulation. These results make clear that criticisms of the mathematical tools (in particular least-squares regression) previously used to derive this version of inclusive fitness are misdirected.
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Affiliation(s)
- François Rousset
- Institut des Sciences de l'Évolution, University of Montpellier, CNRS, IRD, EPHE CC 065, Place E. Bataillon, 34095 Montpellier cedex 05, France.
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26
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Wilder B, Stanley KO. Altruists Proliferate Even at a Selective Disadvantage within Their Own Niche. PLoS One 2015; 10:e0128654. [PMID: 26030734 PMCID: PMC4451246 DOI: 10.1371/journal.pone.0128654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 04/29/2015] [Indexed: 11/19/2022] Open
Abstract
The evolutionary origin of altruism is a long-standing puzzle. Numerous explanations have been proposed, most prominently based on inclusive fitness or group selection. One possibility that has not yet been considered is that new niches will be created disproportionately often when altruism appears, perhaps by chance, causing altruists to be over-represented in such new niches. This effect is a novel variant of group selection in which altruistic groups benefit by discovering unoccupied niches instead of by competing for the limited resources within a single niche. Both an analytical population genetics model and computational simulations support that altruism systematically arises due to this side effect of increased carrying capacity even when it is strongly selected against within any given niche. In fact, even when selection is very strongly negative and altruism does not develop in most populations, it can still be expected to be observed in a consistent fraction of species. The ecological structure provided by niches thereby may be sufficient for altruists to proliferate even if they are always at a disadvantage within each niche considered individually.
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Affiliation(s)
- Bryan Wilder
- Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, FL, USA
| | - Kenneth O. Stanley
- Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, FL, USA
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27
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Social evolution and genetic interactions in the short and long term. Theor Popul Biol 2015; 103:2-26. [PMID: 26003630 DOI: 10.1016/j.tpb.2015.05.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 03/31/2015] [Accepted: 05/04/2015] [Indexed: 11/20/2022]
Abstract
The evolution of social traits remains one of the most fascinating and feisty topics in evolutionary biology even after half a century of theoretical research. W.D. Hamilton shaped much of the field initially with his 1964 papers that laid out the foundation for understanding the effect of genetic relatedness on the evolution of social behavior. Early theoretical investigations revealed two critical assumptions required for Hamilton's rule to hold in dynamical models: weak selection and additive genetic interactions. However, only recently have analytical approaches from population genetics and evolutionary game theory developed sufficiently so that social evolution can be studied under the joint action of selection, mutation, and genetic drift. We review how these approaches suggest two timescales for evolution under weak mutation: (i) a short-term timescale where evolution occurs between a finite set of alleles, and (ii) a long-term timescale where a continuum of alleles are possible and populations evolve continuously from one monomorphic trait to another. We show how Hamilton's rule emerges from the short-term analysis under additivity and how non-additive genetic interactions can be accounted for more generally. This short-term approach reproduces, synthesizes, and generalizes many previous results including the one-third law from evolutionary game theory and risk dominance from economic game theory. Using the long-term approach, we illustrate how trait evolution can be described with a diffusion equation that is a stochastic analogue of the canonical equation of adaptive dynamics. Peaks in the stationary distribution of the diffusion capture classic notions of convergence stability from evolutionary game theory and generally depend on the additive genetic interactions inherent in Hamilton's rule. Surprisingly, the peaks of the long-term stationary distribution can predict the effects of simple kinds of non-additive interactions. Additionally, the peaks capture both weak and strong effects of social payoffs in a manner difficult to replicate with the short-term approach. Together, the results from the short and long-term approaches suggest both how Hamilton's insight may be robust in unexpected ways and how current analytical approaches can expand our understanding of social evolution far beyond Hamilton's original work.
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28
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Barton NH, Servedio MR. The interpretation of selection coefficients. Evolution 2015; 69:1101-12. [PMID: 25790030 DOI: 10.1111/evo.12641] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 02/14/2015] [Indexed: 11/29/2022]
Abstract
Evolutionary biologists have an array of powerful theoretical techniques that can accurately predict changes in the genetic composition of populations. Changes in gene frequencies and genetic associations between loci can be tracked as they respond to a wide variety of evolutionary forces. However, it is often less clear how to decompose these various forces into components that accurately reflect the underlying biology. Here, we present several issues that arise in the definition and interpretation of selection and selection coefficients, focusing on insights gained through the examination of selection coefficients in multilocus notation. Using this notation, we discuss how its flexibility-which allows different biological units to be identified as targets of selection-is reflected in the interpretation of the coefficients that the notation generates. In many situations, it can be difficult to agree on whether loci can be considered to be under "direct" versus "indirect" selection, or to quantify this selection. We present arguments for what the terms direct and indirect selection might best encompass, considering a range of issues, from viability and sexual selection to kin selection. We show how multilocus notation can discriminate between direct and indirect selection, and describe when it can do so.
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Affiliation(s)
- N H Barton
- Institute of Science and Technology, Am Campus 1, A-3400, Klosterneuburg, Austria.
| | - M R Servedio
- Department of Biology, University of North Carolina, Coker Hall CB# 3280, Chapel Hill, North Carolina, 27599
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29
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Schumer M, Cui R, Rosenthal GG, Andolfatto P. Reproductive isolation of hybrid populations driven by genetic incompatibilities. PLoS Genet 2015; 11:e1005041. [PMID: 25768654 PMCID: PMC4359097 DOI: 10.1371/journal.pgen.1005041] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/29/2015] [Indexed: 12/25/2022] Open
Abstract
Despite its role in homogenizing populations, hybridization has also been proposed as a means to generate new species. The conceptual basis for this idea is that hybridization can result in novel phenotypes through recombination between the parental genomes, allowing a hybrid population to occupy ecological niches unavailable to parental species. Here we present an alternative model of the evolution of reproductive isolation in hybrid populations that occurs as a simple consequence of selection against genetic incompatibilities. Unlike previous models of hybrid speciation, our model does not incorporate inbreeding, or assume that hybrids have an ecological or reproductive fitness advantage relative to parental populations. We show that reproductive isolation between hybrids and parental species can evolve frequently and rapidly under this model, even in the presence of substantial ongoing immigration from parental species and strong selection against hybrids. An interesting prediction of our model is that replicate hybrid populations formed from the same pair of parental species can evolve reproductive isolation from each other. This non-adaptive process can therefore generate patterns of species diversity and relatedness that resemble an adaptive radiation. Intriguingly, several known hybrid species exhibit patterns of reproductive isolation consistent with the predictions of our model.
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Affiliation(s)
- Molly Schumer
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Rongfeng Cui
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, Calnali, Hidalgo, Mexico
- Max Planck Institute for the Biology of Ageing, Cologne, Germany
| | - Gil G. Rosenthal
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, Calnali, Hidalgo, Mexico
| | - Peter Andolfatto
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
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30
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Osinga HM, Marshall JAR. Adaptive topographies and equilibrium selection in an evolutionary game. PLoS One 2015; 10:e0116307. [PMID: 25706762 PMCID: PMC4338017 DOI: 10.1371/journal.pone.0116307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 12/04/2014] [Indexed: 11/18/2022] Open
Abstract
It has long been known in the field of population genetics that adaptive topographies, in which population equilibria maximise mean population fitness for a trait regardless of its genetic bases, do not exist. Whether one chooses to model selection acting on a single locus or multiple loci does matter. In evolutionary game theory, analysis of a simple and general game involving distinct roles for the two players has shown that whether strategies are modelled using a single ‘locus’ or one ‘locus’ for each role, the stable population equilibria are unchanged and correspond to the fitness-maximising evolutionary stable strategies of the game. This is curious given the aforementioned population genetical results on the importance of the genetic bases of traits. Here we present a dynamical systems analysis of the game with roles detailing how, while the stable equilibria in this game are unchanged by the number of ‘loci’ modelled, equilibrium selection may differ under the two modelling approaches.
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Affiliation(s)
- Hinke M Osinga
- Department of Mathematics, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - James A R Marshall
- Department of Computer Science, University of Sheffield, Sheffield S1 4DP, United Kingdom
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31
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Gardner A. The genetical theory of multilevel selection. J Evol Biol 2015; 28:305-19. [PMID: 25475922 PMCID: PMC4415573 DOI: 10.1111/jeb.12566] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/28/2014] [Accepted: 12/01/2014] [Indexed: 12/03/2022]
Abstract
The theory of multilevel selection (MLS) is beset with conceptual difficulties. Although it is widely agreed that covariance between group trait and group fitness may arise in the natural world and drive a response to 'group selection', ambiguity exists over the precise meaning of group trait and group fitness and as to whether group selection should be defined according to changes in frequencies of different types of individual or different types of group. Moreover, the theory of MLS has failed to properly engage with the problem of class structure, which greatly limits its empirical application to, for example, social insects whose colonies are structured into separate age, sex, caste and ploidy classes. Here, I develop a genetical theory of MLS, to address these problems. I show that taking a genetical approach facilitates a decomposition of group-level traits - including reproductive success - into the separate contributions made by each constituent individual, even in the context of so-called emergence. However, I uncover a novel problem with the group-oriented approach: in many scenarios, it may not be possible to express a meaningful covariance between trait and fitness at the level of the social group, because the group's constituents belong to separate, irreconcilable classes.
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Affiliation(s)
- A Gardner
- School of Biology, University of St AndrewsSt Andrews, UK
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32
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Affiliation(s)
- Robert Kurzban
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19146;
| | - Maxwell N. Burton-Chellew
- Department of Zoology, University of Oxford, Oxford, OX1 3PS United Kingdom; ,
- Nuffield College, University of Oxford, Oxford, OX1 1NF United Kingdom
| | - Stuart A. West
- Department of Zoology, University of Oxford, Oxford, OX1 3PS United Kingdom; ,
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Abstract
The theories of inclusive fitness and multilevel selection provide alternative perspectives on social evolution. The question of whether these perspectives are of equal generality remains a divisive issue. In an analysis based on the Price equation, Queller argued (by means of a principle he called the separation condition) that the two approaches are subject to the same limitations, arising from their fundamentally quantitative-genetical character. Recently, van Veelen et al. have challenged Queller's results, using this as the basis for a broader critique of the Price equation, the separation condition, and the very notion of inclusive fitness. Here we show that the van Veelen et al. model, when analyzed in the way Queller intended, confirms rather than refutes his original conclusions. We thereby confirm (i) that Queller's separation condition remains a legitimate theoretical principle and (ii) that the standard inclusive fitness and multilevel approaches are indeed subject to the same limitations.
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Affiliation(s)
- Jonathan Birch
- Christ's College, University of Cambridge, St. Andrew's Street, Cambridge CB2 3BU, United Kingdom
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35
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Alpedrinha J, Gardner A, West SA. Haplodiploidy and the Evolution of Eusociality: Worker Revolution. Am Nat 2014; 184:303-17. [DOI: 10.1086/677283] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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36
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Marshall JAR. Generalizations of Hamilton's rule applied to non-additive public goods games with random group size. Front Ecol Evol 2014. [DOI: 10.3389/fevo.2014.00040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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37
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Van Cleve J, Akçay E. PATHWAYS TO SOCIAL EVOLUTION: RECIPROCITY, RELATEDNESS, AND SYNERGY. Evolution 2014; 68:2245-58. [DOI: 10.1111/evo.12438] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 04/16/2014] [Indexed: 01/24/2023]
Affiliation(s)
- Jeremy Van Cleve
- National Evolutionary Synthesis Center (NESCent); 2024 W. Main Street, Suite A200 Durham North Carolina 27705
| | - Erol Akçay
- Department of Biology, University of Pennsylvania; 433 S. University Avenue Philadelphia Pennsylvania 19104
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38
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Abstract
One of the core concepts in social evolution theory is kin selection. Kin selection provides a perspective to understand how natural selection operates when genetically similar individuals are likely to interact. A family-structured population is an excellent example of this, where relatives are engaged in social interactions. Consequences of such social interactions are often described in game-theoretical frameworks, but there is a growing consensus that a naive inclusive fitness accounting with dyadic relatedness coefficients are of limited use when non-additive fitness effects are essential in those situations. Here, I provide a general framework to analyse multiplayer interactions among relatives. Two important results follow from my analysis. First, it is generally necessary to know the n-tuple genetic association of family members when n individuals are engaged in social interactions. However, as a second result, I found that, for a special class of games, we need only measures of lower-order genetic association to fully describe its evolutionary dynamics. I introduce the concept of degree of the game and show how this degree is related to the degree of genetic association.
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Affiliation(s)
- Hisashi Ohtsuki
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan
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39
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Scott-Phillips TC, Laland KN, Shuker DM, Dickins TE, West SA. The niche construction perspective: a critical appraisal. Evolution 2014; 68:1231-43. [PMID: 24325256 PMCID: PMC4261998 DOI: 10.1111/evo.12332] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 11/27/2013] [Indexed: 12/05/2022]
Abstract
Niche construction refers to the activities of organisms that bring about changes in their environments, many of which are evolutionarily and ecologically consequential. Advocates of niche construction theory (NCT) believe that standard evolutionary theory fails to recognize the full importance of niche construction, and consequently propose a novel view of evolution, in which niche construction and its legacy over time (ecological inheritance) are described as evolutionary processes, equivalent in importance to natural selection. Here, we subject NCT to critical evaluation, in the form of a collaboration between one prominent advocate of NCT, and a team of skeptics. We discuss whether niche construction is an evolutionary process, whether NCT obscures or clarifies how natural selection leads to organismal adaptation, and whether niche construction and natural selection are of equivalent explanatory importance. We also consider whether the literature that promotes NCT overstates the significance of niche construction, whether it is internally coherent, and whether it accurately portrays standard evolutionary theory. Our disagreements reflect a wider dispute within evolutionary theory over whether the neo-Darwinian synthesis is in need of reformulation, as well as different usages of some key terms (e.g., evolutionary process).
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40
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Lehmann L, Rousset F. The genetical theory of social behaviour. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130357. [PMID: 24686929 DOI: 10.1098/rstb.2013.0357] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We survey the population genetic basis of social evolution, using a logically consistent set of arguments to cover a wide range of biological scenarios. We start by reconsidering Hamilton's (Hamilton 1964 J. Theoret. Biol. 7, 1-16 (doi:10.1016/0022-5193(64)90038-4)) results for selection on a social trait under the assumptions of additive gene action, weak selection and constant environment and demography. This yields a prediction for the direction of allele frequency change in terms of phenotypic costs and benefits and genealogical concepts of relatedness, which holds for any frequency of the trait in the population, and provides the foundation for further developments and extensions. We then allow for any type of gene interaction within and between individuals, strong selection and fluctuating environments and demography, which may depend on the evolving trait itself. We reach three conclusions pertaining to selection on social behaviours under broad conditions. (i) Selection can be understood by focusing on a one-generation change in mean allele frequency, a computation which underpins the utility of reproductive value weights; (ii) in large populations under the assumptions of additive gene action and weak selection, this change is of constant sign for any allele frequency and is predicted by a phenotypic selection gradient; (iii) under the assumptions of trait substitution sequences, such phenotypic selection gradients suffice to characterize long-term multi-dimensional stochastic evolution, with almost no knowledge about the genetic details underlying the coevolving traits. Having such simple results about the effect of selection regardless of population structure and type of social interactions can help to delineate the common features of distinct biological processes. Finally, we clarify some persistent divergences within social evolution theory, with respect to exactness, synergies, maximization, dynamic sufficiency and the role of genetic arguments.
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Affiliation(s)
- Laurent Lehmann
- Department of Ecology and Evolution, UNIL Sorge, , Le Biophore, 1015 Lausanne, Switzerland
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McGlothlin JW, Wolf JB, Brodie ED, Moore AJ. Quantitative genetic versions of Hamilton's rule with empirical applications. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130358. [PMID: 24686930 PMCID: PMC3982660 DOI: 10.1098/rstb.2013.0358] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Hamilton's theory of inclusive fitness revolutionized our understanding of the evolution of social interactions. Surprisingly, an incorporation of Hamilton's perspective into the quantitative genetic theory of phenotypic evolution has been slow, despite the popularity of quantitative genetics in evolutionary studies. Here, we discuss several versions of Hamilton's rule for social evolution from a quantitative genetic perspective, emphasizing its utility in empirical applications. Although evolutionary quantitative genetics offers methods to measure each of the critical parameters of Hamilton's rule, empirical work has lagged behind theory. In particular, we lack studies of selection on altruistic traits in the wild. Fitness costs and benefits of altruism can be estimated using a simple extension of phenotypic selection analysis that incorporates the traits of social interactants. We also discuss the importance of considering the genetic influence of the social environment, or indirect genetic effects (IGEs), in the context of Hamilton's rule. Research in social evolution has generated an extensive body of empirical work focusing—with good reason—almost solely on relatedness. We argue that quantifying the roles of social and non-social components of selection and IGEs, in addition to relatedness, is now timely and should provide unique additional insights into social evolution.
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Affiliation(s)
- Joel W McGlothlin
- Department of Biological Sciences, Virginia Tech, , Derring Hall 2125, 1405 Perry Street, Blacksburg, VA 24061, USA
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Engen S, Saether BE. EVOLUTION IN FLUCTUATING ENVIRONMENTS: DECOMPOSING SELECTION INTO ADDITIVE COMPONENTS OF THE ROBERTSON-PRICE EQUATION. Evolution 2013; 68:854-65. [DOI: 10.1111/evo.12310] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 10/15/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Steinar Engen
- Department of Mathematical Sciences; Centre for Biodiversity Dynamics; Norwegian University of Science and Technology; N-7491 Trondheim Norway
| | - Bernt-Erik Saether
- Department of Biology; Centre for Biodiversity Dynamics; Norwegian University of Science and Technology; N-7491-Trondheim Norway
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Wyatt GAK, West SA, Gardner A. Can natural selection favour altruism between species? J Evol Biol 2013; 26:1854-65. [PMID: 23848844 DOI: 10.1111/jeb.12195] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/09/2013] [Accepted: 05/06/2013] [Indexed: 11/27/2022]
Abstract
Darwin suggested that the discovery of altruism between species would annihilate his theory of natural selection. However, it has not been formally shown whether between-species altruism can evolve by natural selection, or why this could never happen. Here, we develop a spatial population genetic model of two interacting species, showing that indiscriminate between species helping can be favoured by natural selection. We then ask if this helping behaviour constitutes altruism between species, using a linear-regression analysis to separate the total action of natural selection into its direct and indirect (kin selected) components. We show that our model can be interpreted in two ways, as either altruism within species, or altruism between species. This ambiguity arises depending on whether or not we treat genes in the other species as predictors of an individual's fitness, which is equivalent to treating these individuals as agents (actors or recipients). Our formal analysis, which focuses upon evolutionary dynamics rather than agents and their agendas, cannot resolve which is the better approach. Nonetheless, because a within-species altruism interpretation is always possible, our analysis supports Darwin's suggestion that natural selection does not favour traits that provide benefits exclusively to individuals of other species.
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Affiliation(s)
- G A K Wyatt
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
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Frank SA. Natural selection. VII. History and interpretation of kin selection theory. J Evol Biol 2013; 26:1151-84. [PMID: 23662923 DOI: 10.1111/jeb.12131] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 11/26/2012] [Accepted: 11/29/2012] [Indexed: 11/28/2022]
Abstract
Kin selection theory is a kind of causal analysis. The initial form of kin selection ascribed cause to costs, benefits and genetic relatedness. The theory then slowly developed a deeper and more sophisticated approach to partitioning the causes of social evolution. Controversy followed because causal analysis inevitably attracts opposing views. It is always possible to separate total effects into different component causes. Alternative causal schemes emphasize different aspects of a problem, reflecting the distinct goals, interests and biases of different perspectives. For example, group selection is a particular causal scheme with certain advantages and significant limitations. Ultimately, to use kin selection theory to analyse natural patterns and to understand the history of debates over different approaches, one must follow the underlying history of causal analysis. This article describes the history of kin selection theory, with emphasis on how the causal perspective improved through the study of key patterns of natural history, such as dispersal and sex ratio, and through a unified approach to demographic and social processes. Independent historical developments in the multivariate analysis of quantitative traits merged with the causal analysis of social evolution by kin selection.
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Affiliation(s)
- S A Frank
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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Abstract
Explaining cooperation in groups remains a key problem because reciprocity breaks down between more than two. Punishing individuals who contribute little provides a potential answer but changes the dilemma to why pay the costs of punishing which, like cooperation itself, provides a public good. Nevertheless, people are observed to punish others in behavioural economic games, posing a problem for existing theory which highlights the difficulty in explaining the spread and persistence of punishment. Here, I consider the apparent mismatch between theory and evidence and show by means of instructive analysis and simulation how much of the experimental evidence for punishment comes from scenarios in which punishers may expect to obtain a net benefit from punishing free-riders. In repeated games within groups, punishment works by imposing costs on defectors so that it pays them to switch to cooperating. Both punishers and non-punishers then benefit from the resulting increase in cooperation, hence investing in punishment can constitute a social dilemma. However, I show the conditions in which the benefits of increased cooperation are so great that they more than offset the costs of punishing, thereby removing the temptation to free-ride on others' investments and making punishment explicable in terms of direct self-interest. Crucially, this is because of the leveraging effect imposed in typical studies whereby people can pay a small cost to inflict a heavy loss on a punished individual. In contrast to previous models suggesting punishment is disadvantaged when rare, I show it can invade until it comes into a producer-scrounger equilibrium with non-punishers. I conclude that adding punishment to an iterated public goods game can solve the problem of achieving cooperation by removing the social dilemma.
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Affiliation(s)
- Gilbert Roberts
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle, United
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Reproductive skew can provide a net advantage in both conditional and unconditional social interactions. Theor Popul Biol 2012; 82:200-8. [DOI: 10.1016/j.tpb.2012.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 06/07/2012] [Accepted: 06/11/2012] [Indexed: 11/20/2022]
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Rankin DJ, Turner LA, Heinemann JA, Brown SP. The coevolution of toxin and antitoxin genes drives the dynamics of bacterial addiction complexes and intragenomic conflict. Proc Biol Sci 2012; 279:3706-15. [PMID: 22787022 PMCID: PMC3415908 DOI: 10.1098/rspb.2012.0942] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 06/20/2012] [Indexed: 12/12/2022] Open
Abstract
Bacterial genomes commonly contain 'addiction' gene complexes that code for both a toxin and a corresponding antitoxin. As long as both genes are expressed, cells carrying the complex can remain healthy. However, loss of the complex (including segregational loss in daughter cells) can entail death of the cell. We develop a theoretical model to explore a number of evolutionary puzzles posed by toxin-antitoxin (TA) population biology. We first extend earlier results demonstrating that TA complexes can spread on plasmids, as an adaptation to plasmid competition in spatially structured environments, and highlight the role of kin selection. We then considered the emergence of TA complexes on plasmids from previously unlinked toxin and antitoxin genes. We find that one of these traits must offer at least initially a direct advantage in some but not all environments encountered by the evolving plasmid population. Finally, our study predicts non-transitive 'rock-paper-scissors' dynamics to be a feature of intragenomic conflict mediated by TA complexes. Intragenomic conflict could be sufficient to select deleterious genes on chromosomes and helps to explain the previously perplexing observation that many TA genes are found on bacterial chromosomes.
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Affiliation(s)
- Daniel J. Rankin
- Institute of Evolutionary Biology and Environmental Studies, University of Zürich, Building Y27, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Swiss Institute of Bioinformatics, Quartier Sorge Bâtiment Génopode, 1015 Lausanne, Switzerland
| | - Leighton A. Turner
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Jack A. Heinemann
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Sam P. Brown
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
- Centre for Immunity, Infection and Evolution, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK
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Dobata S. ARMS RACE BETWEEN SELFISHNESS AND POLICING: TWO-TRAIT QUANTITATIVE GENETIC MODEL FOR CASTE FATE CONFLICT IN EUSOCIAL HYMENOPTERA. Evolution 2012. [DOI: 10.1111/j.1558-5646.2012.01745.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Inglis RF, Brown SP, Buckling A. Spite versus cheats: competition among social strategies shapes virulence in Pseudomonas aeruginosa. Evolution 2012; 66:3472-84. [PMID: 23106711 PMCID: PMC3795443 DOI: 10.1111/j.1558-5646.2012.01706.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Social interactions have been shown to play an important role in bacterial evolution and virulence. The majority of empirical studies conducted have only considered social traits in isolation, yet numerous social traits, such as the production of spiteful bacteriocins (anticompetitor toxins) and iron-scavenging siderophores (a public good) by the opportunistic pathogen Pseudomonas aeruginosa, are frequently expressed simultaneously. Crucially, both bacteriocin production and siderophore cheating can be favored under the same competitive conditions, and we develop theory and carry out experiments to determine how the success of a bacteriocin-producing genotype is influenced by social cheating of susceptible competitors and the resultant impact on disease severity (virulence). Consistent with our theoretical predictions, we find that the spiteful genotype is favored at higher local frequencies when competing against public good cheats. Furthermore, the relationship between spite frequency and virulence is significantly altered when the spiteful genotype is competed against cheats compared with cooperators. These results confirm the ecological and evolutionary importance of considering multiple social traits simultaneously. Moreover, our results are consistent with recent theory regarding the invasion conditions for strong reciprocity (helping cooperators and harming noncooperators).
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Affiliation(s)
- R Fredrik Inglis
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom.
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Abstract
The Price equation partitions total evolutionary change into two components. The first component provides an abstract expression of natural selection. The second component subsumes all other evolutionary processes, including changes during transmission. The natural selection component is often used in applications. Those applications attract widespread interest for their simplicity of expression and ease of interpretation. Those same applications attract widespread criticism by dropping the second component of evolutionary change and by leaving unspecified the detailed assumptions needed for a complete study of dynamics. Controversies over approximation and dynamics have nothing to do with the Price equation itself, which is simply a mathematical equivalence relation for total evolutionary change expressed in an alternative form. Disagreements about approach have to do with the tension between the relative valuation of abstract versus concrete analyses. The Price equation's greatest value has been on the abstract side, particularly the invariance relations that illuminate the understanding of natural selection. Those abstract insights lay the foundation for applications in terms of kin selection, information theory interpretations of natural selection and partitions of causes by path analysis. I discuss recent critiques of the Price equation by Nowak and van Veelen.
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Affiliation(s)
- S A Frank
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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