Evidence, Other Approaches, and Further Topics

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Social Evolution ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Replicator Dynamics ◽  
Empirical Support ◽  
Natural World ◽  
Price Equation ◽  
Evolution Theory ◽  
Inclusive Fitness Theory ◽  
The Many

This book has examined the genesis, the logic, and the generality of social evolution theory. In particular, it has presented evolutionary explanations of the many social behaviors we observe in the natural world by showing that William D. Hamilton's inclusive fitness theory provides the necessary generalization of classical Darwin–Wallace–Fisher fitness. This concluding chapter discusses the limitations of the analyses presented in this book and assesses the empirical support for inclusive fitness theory, focusing on microbial altruism, help in cooperative breeders, reproductive restraint in eusocial species, and the evolution of eusociality and cooperative breeding. It also considers more advanced topics in social evolution theory, including sex allocation, genetic kin recognition, spite, and the evolution of organismality. Finally, it reviews theoretical approaches to studying social evolution other than replicator dynamics and the Price equation, such as population genetics, class-structured populations, and maximization approaches.

Social Evolution and Inclusive Fitness Theory

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Social Behavior ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Natural World ◽  
Inclusive Fitness Theory ◽  
Key Concepts ◽  
Underlying Causes ◽  
Powerful Explanation ◽  
Work Supports ◽  
General Explanation

Social behavior has long puzzled evolutionary biologists, since the classical theory of natural selection maintains that individuals should not sacrifice their own fitness to affect that of others. This book argues that a theory first presented in 1963 by William D. Hamilton—inclusive fitness theory—provides the most fundamental and general explanation for the evolution and maintenance of social behaviors in the natural world. The book guides readers through the vast and confusing literature on the evolution of social behavior, introducing and explaining the competing theories that claim to provide answers to questions such as why animals evolve to behave altruistically. Using simple statistical language and techniques that practicing biologists will be familiar with, the book provides a comprehensive yet easily understandable treatment of key concepts and their repeated misinterpretations. Particular attention is paid to how more realistic features of behavior, such as nonadditivity and conditionality, can complicate analysis. The book highlights the general problem of identifying the underlying causes of evolutionary change, and proposes fruitful approaches to doing so in the study of social evolution. It describes how inclusive fitness theory addresses both simple and complex social scenarios, the controversies surrounding the theory, and how experimental work supports the theory as the most powerful explanation for social behavior and its evolution.

Social Evolution, Hamilton’s Rule, and Inclusive Fitness

2018 ◽  
Author(s):  
Samir Okasha
Keyword(s):  
Social Behaviour ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Popular Approach ◽  
Hamilton’S Rule ◽  
Inclusive Fitness Theory ◽  
The Social ◽  
Social Encounters ◽  
The Individual ◽  
Hamilton's Rule

Inclusive fitness theory, originally due to W. D. Hamilton, is a popular approach to the study of social evolution, but shrouded in controversy. The theory contains two distinct aspects: Hamilton’s rule (rB > C); and the idea that individuals will behave as if trying to maximize their inclusive fitness in social encounters. These two aspects of the theory are logically separable but often run together. A generalized version of Hamilton’s rule can be formulated that is always true, though whether it is causally meaningful is debatable. However, the individual maximization claim only holds true if the payoffs from the social encounter are additive. The notion that inclusive fitness is the ‘goal’ of individuals’ social behaviour is less robust than some of its advocates acknowledge.

scholarly journals War and peace: social interactions in infections

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130365 ◽  
Author(s):  
Helen C. Leggett ◽  
Sam P. Brown ◽  
Sarah E. Reece
Keyword(s):  
Species Interactions ◽  
Disease Ecology ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Experimental Tests ◽  
Microbial Pathogens ◽  
Emergent Properties ◽  
Social Strategies ◽  
Inclusive Fitness Theory ◽  
Social Behaviours

One of the most striking facts about parasites and microbial pathogens that has emerged in the fields of social evolution and disease ecology in the past few decades is that these simple organisms have complex social lives, indulging in a variety of cooperative, communicative and coordinated behaviours. These organisms have provided elegant experimental tests of the importance of relatedness, kin discrimination, cooperation and competition, in driving the evolution of social strategies. Here, we briefly review the social behaviours of parasites and microbial pathogens, including their contributions to virulence, and outline how inclusive fitness theory has helped to explain their evolution. We then take a mechanistically inspired ‘bottom-up’ approach, discussing how key aspects of the ways in which parasites and pathogens exploit hosts, namely public goods, mobile elements, phenotypic plasticity, spatial structure and multi-species interactions, contribute to the emergent properties of virulence and transmission. We argue that unravelling the complexities of within-host ecology is interesting in its own right, and also needs to be better incorporated into theoretical evolution studies if social behaviours are to be understood and used to control the spread and severity of infectious diseases.

scholarly journals Male relatedness and familiarity are required to modulate male-induced harm to females in Drosophila

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170441 ◽  
Author(s):  
Sally Le Page ◽  
Irem Sepil ◽  
Ewan Flintham ◽  
Tommaso Pizzari ◽  
Pau Carazo ◽  
...  
Keyword(s):  
Potential Role ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Female Reproduction ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Indirect Fitness ◽  
Female Lifespan

Males compete over mating and fertilization, and often harm females in the process. Inclusive fitness theory predicts that increasing relatedness within groups of males may relax competition and discourage male harm of females as males gain indirect benefits. Recent studies in Drosophila melanogaster are consistent with these predictions, and have found that within-group male relatedness increases female fitness, though others have found no effects. Importantly, these studies did not fully disentangle male genetic relatedness from larval familiarity, so the extent to which modulation of harm to females is explained by male familiarity remains unclear. Here we performed a fully factorial design, isolating the effects of male relatedness and larval familiarity on female harm. While we found no differences in male courtship or aggression, there was a significant interaction between male genetic relatedness and familiarity on female reproduction and survival. Relatedness among males increased female lifespan, reproductive lifespan and overall reproductive success, but only when males were familiar. By showing that both male relatedness and larval familiarity are required to modulate female harm, these findings reconcile previous studies, shedding light on the potential role of indirect fitness effects on sexual conflict and the mechanisms underpinning kin recognition in fly populations.

scholarly journals The validity and value of inclusive fitness theory

2011 ◽  
Vol 278 (1723) ◽  
pp. 3313-3320 ◽  
Author(s):  
Andrew F. G. Bourke
Keyword(s):  
Kin Selection ◽  
Evolutionary Biology ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Evidence Base ◽  
Alternative Theory ◽  
Selection Theory ◽  
Inclusive Fitness Theory ◽  
Evolution Of Eusociality ◽  
Natural Selection Theory

Social evolution is a central topic in evolutionary biology, with the evolution of eusociality (societies with altruistic, non-reproductive helpers) representing a long-standing evolutionary conundrum. Recent critiques have questioned the validity of the leading theory for explaining social evolution and eusociality, namely inclusive fitness (kin selection) theory. I review recent and past literature to argue that these critiques do not succeed. Inclusive fitness theory has added fundamental insights to natural selection theory. These are the realization that selection on a gene for social behaviour depends on its effects on co-bearers, the explanation of social behaviours as unalike as altruism and selfishness using the same underlying parameters, and the explanation of within-group conflict in terms of non-coinciding inclusive fitness optima. A proposed alternative theory for eusocial evolution assumes mistakenly that workers' interests are subordinate to the queen's, contains no new elements and fails to make novel predictions. The haplodiploidy hypothesis has yet to be rigorously tested and positive relatedness within diploid eusocial societies supports inclusive fitness theory. The theory has made unique, falsifiable predictions that have been confirmed, and its evidence base is extensive and robust. Hence, inclusive fitness theory deserves to keep its position as the leading theory for social evolution.

scholarly journals Helping in cooperatively breeding long-tailed tits: a test of Hamilton's rule

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130565 ◽  
Author(s):  
Ben J. Hatchwell ◽  
Philippa R. Gullett ◽  
Mark J. Adams
Keyword(s):  
Social Evolution ◽  
Inclusive Fitness ◽  
Empirical Studies ◽  
Alloparental Care ◽  
Hamilton’S Rule ◽  
Long Term Study ◽  
Inclusive Fitness Theory ◽  
Cooperatively Breeding ◽  
Helping Behaviour ◽  
Hamilton's Rule

Inclusive fitness theory provides the conceptual framework for our current understanding of social evolution, and empirical studies suggest that kin selection is a critical process in the evolution of animal sociality. A key prediction of inclusive fitness theory is that altruistic behaviour evolves when the costs incurred by an altruist ( c ) are outweighed by the benefit to the recipient ( b ), weighted by the relatedness of altruist to recipient ( r ), i.e. Hamilton's rule rb > c . Despite its central importance in social evolution theory, there have been relatively few empirical tests of Hamilton's rule, and hardly any among cooperatively breeding vertebrates, leading some authors to question its utility. Here, we use data from a long-term study of cooperatively breeding long-tailed tits Aegithalos caudatus to examine whether helping behaviour satisfies Hamilton's condition for the evolution of altruism. We show that helpers are altruistic because they incur survival costs through the provision of alloparental care for offspring. However, they also accrue substantial benefits through increased survival of related breeders and offspring, and despite the low average relatedness of helpers to recipients, these benefits of helping outweigh the costs incurred. We conclude that Hamilton's rule for the evolution of altruistic helping behaviour is satisfied in this species.

scholarly journals Cheating in the Viral World

2019 ◽  
Author(s):  
Asher Leeks ◽  
Melanie Ghoul ◽  
Stuart West
Keyword(s):  
Evolutionary Theory ◽  
Social Evolution ◽  
Viral Infections ◽  
Viral Evolution ◽  
Natural World ◽  
Intervention Strategies ◽  
Cooperative Behaviour ◽  
Evolution Theory ◽  
Different Types

The extent to which cheating occurs in the natural world has proved contentious. We suggest that viruses offer an exceptional opportunity for studying cheats, individuals that exploit the cooperative behaviour of others. In particular, we show that: (1) cheating is common in viruses; (2) there are many different types of viral cheat; (3) viral cheats offer novel problems for social evolution theory; (4) viruses offer excellent empirical opportunities for studying cheating; (5) cheating shows that viral populations experience substantial conflict, changing how we think about how viral infections evolve; (6) evolutionary theory about cheating could help us understand viral evolution; (7) a greater understanding of cheating in viruses could aid viral intervention strategies.

Inclusive Fitness and Hamilton’s Rule

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Sex Allocation ◽  
Charles Darwin ◽  
Inclusive Fitness ◽  
Price Equation ◽  
Additive Effects ◽  
Eusocial Insect ◽  
Hamilton’S Rule ◽  
Biological Phenomena ◽  
Inclusive Fitness Theory ◽  
Hamilton's Rule

This chapter examines how the logic of inclusive fitness theory can be mathematically formalized using the Price equation, and how that formalization can be used to derive Hamilton's rule in its simplest form, as applied to unconditional behaviors having additive effects on fitness. Various biological phenomena, such as sex allocation and working policing within eusocial insect colonies, have been analyzed by considering what strategies maximize individuals' inclusive fitness, and how observed social behaviors should correlate with quantities such as relatedness. The chapter derives Hamilton's rule by introducing some notation for the effects of behaviors on fitnesses of individuals that interact socially, to make explicit precisely how genes (and later phenotypes) affect fitness, and to give a general form of Hamilton's rule that will apply to any (unconditional, additive) behavior regardless of its details. It shows that inclusive fitness is a genuinely novel extension of the classical fitness studied by Charles Darwin, R. A. Fisher, and others.

Social Behavior and Evolutionary Thought

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Natural Selection ◽  
Mathematical Theory ◽  
Group Selection ◽  
Inclusive Fitness ◽  
Price Equation ◽  
Inclusive Fitness Theory ◽  
Evolutionary Thought ◽  
Multilevel Selection Theory ◽  
The Individual ◽  
Evolutionary Explanations

This book demonstrates the generality of inclusive fitness theory, with particular emphasis on its fundamental evolutionary logic. It presents the basic mathematical theory of natural selection and shows how inclusive fitness theory deals with more complicated social scenarios. Topics include the Price equation, Hamilton's rule, nonadditive interactions, conditional behaviors, heritability, and maximization of inclusive fitness. This chapter provides a brief historical introduction to the problem of apparent design in biology, evolutionary explanations of this, and in particular, evolutionary explanations of individual behaviors that appear designed to benefit not the individual themselves, but other members of their species. It examines how social behaviors can be shaped by natural selection and discusses the problem of providing an evolutionary explanation of self-sacrifice by individuals, altruism in group selection, and multilevel selection theory.

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