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Santostefano F, Fraser Franco M, Montiglio PO. Social interactions generate complex selection patterns in virtual worlds. J Evol Biol 2024; 37:807-817. [PMID: 38703094 DOI: 10.1093/jeb/voae055] [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: 07/12/2023] [Revised: 02/13/2024] [Accepted: 05/02/2024] [Indexed: 05/06/2024]
Abstract
Understanding the influence of social interactions on individual fitness is key to improving our predictions of phenotypic evolution. However, we often overlook the different components of selection regimes arising from interactions among organisms, including social, correlational, and indirect selection. This is due to the challenging sampling efforts required in natural populations to measure phenotypes expressed during interactions and individual fitness. Furthermore, behaviours are crucial in mediating social interactions, yet few studies have explicitly quantified these selection components on behavioural traits. In this study, we capitalize on an online multiplayer video game as a source of extensive data recording direct social interactions among prey, where prey collaborate to escape a predator in realistic ecological settings. We estimate natural and social selection and their contribution to total selection on behavioural traits mediating competition, cooperation, and predator-prey interactions. Behaviours of other prey in a group impact an individual's survival, and thus are under social selection. Depending on whether selection pressures on behaviours are synergistic or conflicting, social interactions enhance or mitigate the strength of natural selection, although natural selection remains the main driving force. Indirect selection through correlations among traits also contributed to the total selection. Thus, failing to account for the effects of social interactions and indirect selection would lead to a misestimation of the total selection acting on traits. Dissecting the contribution of each component to the total selection differential allowed us to investigate the causal mechanisms relating behaviour to fitness and quantify the importance of the behaviours of conspecifics as agents of selection. Our study emphasizes that social interactions generate complex selective regimes even in a relatively simple ecological environment.
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Affiliation(s)
- Francesca Santostefano
- Centre for Ecology and Conservation, University of Exeter, Cornwall, United Kingdom
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Maxime Fraser Franco
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
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2
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Fisher DN. Direct and indirect phenotypic effects on sociability indicate potential to evolve. J Evol Biol 2023; 36:209-220. [PMID: 36263954 PMCID: PMC10092521 DOI: 10.1111/jeb.14110] [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: 05/19/2022] [Revised: 07/19/2022] [Accepted: 09/02/2022] [Indexed: 01/11/2023]
Abstract
The decision to leave or join a group is important as group size influences many aspects of organisms' lives and their fitness. This tendency to socialise with others, sociability, should be influenced by genes carried by focal individuals (direct genetic effects) and by genes in partner individuals (indirect genetic effects), indicating the trait's evolution could be slower or faster than expected. However, estimating these genetic parameters is difficult. Here, in a laboratory population of the cockroach Blaptica dubia, I estimate phenotypic parameters for sociability: repeatability (R) and repeatable influence (RI), that indicate whether direct and indirect genetic effects respectively are likely. I also estimate the interaction coefficient (Ψ), which quantifies how strongly a partner's trait influences the phenotype of the focal individual and is key in models for the evolution of interacting phenotypes. Focal individuals were somewhat repeatable for sociability across a 3-week period (R = 0.080), and partners also had marginally consistent effects on focal sociability (RI = 0.053). The interaction coefficient was non-zero, although in opposite sign for the sexes; males preferred to associate with larger individuals (Ψmale = -0.129), while females preferred to associate with smaller individuals (Ψfemale = 0.071). Individual sociability was consistent between dyadic trials and in social networks of groups. These results provide phenotypic evidence that direct and indirect genetic effects have limited influence on sociability, with perhaps most evolutionary potential stemming from heritable effects of the body mass of partners. Sex-specific interaction coefficients may produce sexual conflict and the evolution of sexual dimorphism in social behaviour.
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Affiliation(s)
- David N Fisher
- School of Biological Sciences, King's College, University of Aberdeen, Aberdeen, UK
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3
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McGlothlin JW, Akçay E, Brodie ED, Moore AJ, Van Cleve J. A Synthesis of Game Theory and Quantitative Genetic Models of Social Evolution. J Hered 2022; 113:109-119. [PMID: 35174861 DOI: 10.1093/jhered/esab064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 10/15/2021] [Indexed: 11/12/2022] Open
Abstract
Two popular approaches for modeling social evolution, evolutionary game theory and quantitative genetics, ask complementary questions but are rarely integrated. Game theory focuses on evolutionary outcomes, with models solving for evolutionarily stable equilibria, whereas quantitative genetics provides insight into evolutionary processes, with models predicting short-term responses to selection. Here we draw parallels between evolutionary game theory and interacting phenotypes theory, which is a quantitative genetic framework for understanding social evolution. First, we show how any evolutionary game may be translated into two quantitative genetic selection gradients, nonsocial and social selection, which may be used to predict evolutionary change from a single round of the game. We show that synergistic fitness effects may alter predicted selection gradients, causing changes in magnitude and sign as the population mean evolves. Second, we show how evolutionary games involving plastic behavioral responses to partners can be modeled using indirect genetic effects, which describe how trait expression changes in response to genes in the social environment. We demonstrate that repeated social interactions in models of reciprocity generate indirect effects and conversely, that estimates of parameters from indirect genetic effect models may be used to predict the evolution of reciprocity. We argue that a pluralistic view incorporating both theoretical approaches will benefit empiricists and theorists studying social evolution. We advocate the measurement of social selection and indirect genetic effects in natural populations to test the predictions from game theory and, in turn, the use of game theory models to aid in the interpretation of quantitative genetic estimates.
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Affiliation(s)
- Joel W McGlothlin
- Department of Biological Sciences, Virginia Tech, Derring Hall Room 2125, 926 West Campus Drive (MC 0406), Blacksburg, VA 24061, USA
| | - Erol Akçay
- Department of Biology, University of Pennsylvania, 102 Leidy Laboratories, 433 South University Avenue, Philadelphia, PA 19104, USA
| | - Edmund D Brodie
- Department of Biology and Mountain Lake Biological Station, University of Virginia, 485 McCormick Road, P.O. Box 400328, Charlottesville, VA 22904, USA
| | - Allen J Moore
- College of Agricultural and Environmental Sciences, University of Georgia, 109 Conner Hall, 147 Cedar Street, Athens, GA 30602, USA
| | - Jeremy Van Cleve
- Department of Biology, University of Kentucky, 101 T. H. Morgan Building, Lexington, KY 40506, USA
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McGlothlin JW, Fisher DN. Social Selection and the Evolution of Maladaptation. J Hered 2021; 113:61-68. [PMID: 34850889 DOI: 10.1093/jhered/esab061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 10/07/2021] [Indexed: 11/15/2022] Open
Abstract
Evolution by natural selection is often viewed as a process that inevitably leads to adaptation or an increase in population fitness over time. However, maladaptation, an evolved decrease in fitness, may also occur in response to natural selection under some conditions. Social selection, which arises from the effects of social partners on fitness, has been identified as a potential cause of maladaptation, but we lack a general rule identifying when social selection should lead to a decrease in population mean fitness. Here we use a quantitative genetic model to develop such a rule. We show that maladaptation is most likely to occur when social selection is strong relative to nonsocial selection and acts in an opposing direction. In this scenario, the evolution of traits that impose fitness costs on others may outweigh evolved gains in fitness for the individual, leading to a net decrease in population mean fitness. Furthermore, we find that maladaptation may also sometimes occur when phenotypes of interacting individuals negatively covary. We outline the biological situations where maladaptation in response to social selection can be expected, provide both quantitative genetic and phenotypic versions of our derived result, and suggest what empirical work would be needed to test it. We also consider the effect of social selection on inclusive fitness and support previous work showing that inclusive fitness cannot suffer an evolutionary decrease. Taken together, our results show that social selection may decrease population mean fitness when it opposes individual-level selection, even as inclusive fitness increases.
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Affiliation(s)
- Joel W McGlothlin
- Department of Biological Sciences, Virginia Tech, Derring Hall Room 2125, 926 West Campus Drive (MC 0406), Blacksburg, VA 24061, USA
| | - David N Fisher
- School of Biological Sciences, University of Aberdeen, King's College, Aberdeen AB24 3FX, UK
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Moore AJ, McGlothlin JW, Wolf JB. Runaway evolution from male-male competition. Ecol Lett 2021; 25:295-306. [PMID: 34784652 PMCID: PMC9299654 DOI: 10.1111/ele.13921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 11/29/2022]
Abstract
Wondrously elaborate weapons and displays that appear to be counter to ecological optima are widespread features of male contests for mates across the animal kingdom. To understand how such diverse traits evolve, here we develop a quantitative genetic model of sexual selection for a male signaling trait that mediates aggression in male‐male contests and show that an honest indicator of aggression can generate selection on itself by altering the social environment. This can cause selection to accelerate as the trait is elaborated, leading to runaway evolution. Thus, an evolving source of selection provided by the social environment is the fundamental unifying feature of runaway sexual selection driven by either male‐male competition or female mate choice. However, a key difference is that runaway driven by male‐male competition requires signal honesty. Our model identifies simple conditions that provide clear, testable predictions for empirical studies using standard quantitative genetic methods.
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Affiliation(s)
- Allen J Moore
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Joel W McGlothlin
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Jason B Wolf
- Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Bath, UK
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McAdam AG, Webber QMR, Dantzer B, Lane JE, Boutin S. Social Effects on Annual Fitness in Red Squirrels. J Hered 2021; 113:69-78. [PMID: 34679173 DOI: 10.1093/jhered/esab051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 09/01/2021] [Indexed: 11/12/2022] Open
Abstract
When resources are limited, mean fitness is constrained and competition can cause genes and phenotypes to enhance an individual's own fitness while reducing the fitness of their competitors. Negative social effects on fitness have the potential to constrain adaptation, but the interplay between ecological opportunity and social constraints on adaptation remains poorly studied in nature. Here, we tested for evidence of phenotypic social effects on annual fitness (survival and reproductive success) in a long-term study of wild North American red squirrels (Tamiasciurus hudsonicus) under conditions of both resource limitation and super-abundant food resources. When resources were limited, populations remained stable or declined, and there were strong negative social effects on annual survival and reproductive success. That is, mean fitness was constrained and individuals had lower fitness when other nearby individuals had higher fitness. In contrast, when food resources were super-abundant, populations grew and social constraints on reproductive success were greatly reduced or eliminated. Unlike reproductive success, social constraints on survival were not significantly reduced when food resources were super-abundant. These findings suggest resource-dependent social constraints on a component of fitness, which have important potential implications for evolution and adaptation.
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Affiliation(s)
- Andrew G McAdam
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Boulder, Colorado, USA
| | - Quinn M R Webber
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Boulder, Colorado, USA
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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Fisher DN, LeGrice RJ, Painting CJ. Social selection is density dependent but makes little contribution to total selection in New Zealand giraffe weevils. Proc Biol Sci 2021; 288:20210696. [PMID: 34074126 PMCID: PMC8170205 DOI: 10.1098/rspb.2021.0696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/07/2021] [Indexed: 11/12/2022] Open
Abstract
Social selection occurs when traits of interaction partners influence an individual's fitness and can alter total selection strength. However, we have little idea of what factors influence social selection's strength. Further, social selection only contributes to overall selection when there is phenotypic assortment, but simultaneous estimates of social selection and phenotypic assortment are rare. Here, we estimated social selection on body size in a wild population of New Zealand giraffe weevils (Lasiorhynchus barbicornis). We measured phenotypic assortment by body size and tested whether social selection varied with sex ratio, density and interacted with the body size of the focal individual. Social selection was limited and unaffected by sex ratio or the size of the focal individual. However, at high densities social selection was negative for both sexes, consistent with size-based competitive interactions for access to mates. Phenotypic assortment was always close to zero, indicating negative social selection at high densities will not impede the evolution of larger body sizes. Despite its predicted importance, social selection may only influence evolutionary change in specific contexts, leaving direct selection to drive evolutionary change.
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Affiliation(s)
- David N. Fisher
- School of Biological Sciences, University of Aberdeen, King's College, Aberdeen AB243FX, UK
| | - Rebecca J. LeGrice
- Te Aka Mātuatua School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Christina J. Painting
- Te Aka Mātuatua School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
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Fisher DN, Pruitt JN. Insights from the study of complex systems for the ecology and evolution of animal populations. Curr Zool 2020; 66:1-14. [PMID: 32467699 PMCID: PMC7245006 DOI: 10.1093/cz/zoz016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/02/2019] [Indexed: 12/01/2022] Open
Abstract
Populations of animals comprise many individuals, interacting in multiple contexts, and displaying heterogeneous behaviors. The interactions among individuals can often create population dynamics that are fundamentally deterministic yet display unpredictable dynamics. Animal populations can, therefore, be thought of as complex systems. Complex systems display properties such as nonlinearity and uncertainty and show emergent properties that cannot be explained by a simple sum of the interacting components. Any system where entities compete, cooperate, or interfere with one another may possess such qualities, making animal populations similar on many levels to complex systems. Some fields are already embracing elements of complexity to help understand the dynamics of animal populations, but a wider application of complexity science in ecology and evolution has not occurred. We review here how approaches from complexity science could be applied to the study of the interactions and behavior of individuals within animal populations and highlight how this way of thinking can enhance our understanding of population dynamics in animals. We focus on 8 key characteristics of complex systems: hierarchy, heterogeneity, self-organization, openness, adaptation, memory, nonlinearity, and uncertainty. For each topic we discuss how concepts from complexity theory are applicable in animal populations and emphasize the unique insights they provide. We finish by outlining outstanding questions or predictions to be evaluated using behavioral and ecological data. Our goal throughout this article is to familiarize animal ecologists with the basics of each of these concepts and highlight the new perspectives that they could bring to variety of subfields.
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Affiliation(s)
- David N Fisher
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
| | - Jonathan N Pruitt
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
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Evans SR, Postma E, Sheldon BC. It takes two: Heritable male effects on reproductive timing but not clutch size in a wild bird population*. Evolution 2020; 74:2320-2331. [DOI: 10.1111/evo.13980] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 03/19/2020] [Accepted: 04/02/2020] [Indexed: 12/29/2022]
Affiliation(s)
- Simon R. Evans
- Edward Grey Institute, Department of Zoology University of Oxford Oxford OX1 3SZ UK
- Centre for Ecology and Conservation University of Exeter Penryn TR10 9FE UK
| | - Erik Postma
- Centre for Ecology and Conservation University of Exeter Penryn TR10 9FE UK
| | - Ben C. Sheldon
- Edward Grey Institute, Department of Zoology University of Oxford Oxford OX1 3SZ UK
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Santostefano F, Garant D, Bergeron P, Montiglio P, Réale D. Social selection acts on behavior and body mass but does not contribute to the total selection differential in eastern chipmunks. Evolution 2019; 74:89-102. [DOI: 10.1111/evo.13875] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 09/23/2019] [Accepted: 10/21/2019] [Indexed: 11/27/2022]
Affiliation(s)
- Francesca Santostefano
- Département des Sciences BiologiquesUniversité du Québec à Montréal Montréal Canada
- Département de Biologie, Faculté des SciencesUniversité de Sherbrooke Sherbrooke Québec Canada
| | - Dany Garant
- Département de Biologie, Faculté des SciencesUniversité de Sherbrooke Sherbrooke Québec Canada
| | - Patrick Bergeron
- Department of Biological SciencesBishop's University Sherbrooke Québec Canada
| | | | - Denis Réale
- Département des Sciences BiologiquesUniversité du Québec à Montréal Montréal Canada
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Trubenová B, Hager R. Green beards in the light of indirect genetic effects. Ecol Evol 2019; 9:9597-9608. [PMID: 31534678 PMCID: PMC6745669 DOI: 10.1002/ece3.5484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/26/2019] [Accepted: 07/02/2019] [Indexed: 11/14/2022] Open
Abstract
The green-beard effect is one proposed mechanism predicted to underpin the evolution of altruistic behavior. It relies on the recognition and the selective help of altruists to each other in order to promote and sustain altruistic behavior. However, this mechanism has often been dismissed as unlikely or uncommon, as it is assumed that both the signaling trait and altruistic trait need to be encoded by the same gene or through tightly linked genes. Here, we use models of indirect genetic effects (IGEs) to find the minimum correlation between the signaling and altruistic trait required for the evolution of the latter. We show that this correlation threshold depends on the strength of the interaction (influence of the green beard on the expression of the altruistic trait), as well as the costs and benefits of the altruistic behavior. We further show that this correlation does not necessarily have to be high and support our analytical results by simulations.
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Affiliation(s)
| | - Reinmar Hager
- Evolution and Genomic Systems, School of Biological Sciences, Manchester Academic Health Science Center, Faculty of Biology, Medicine and HealthThe University of ManchesterManchesterUK
- Present address:
Computational and Evolutionary Biology, Faculty of Life SciencesMichael Smith BuildingManchesterUK
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