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 Persistent Misunderstandings of Inclusive Fitness and Kin Selection: Their Ubiquitous Appearance in Social Psychology Textbooks

2007 ◽  
Vol 5 (4) ◽  
pp. 147470490700500 ◽  
Author(s):  
Justin H. Park
Keyword(s):  
Social Psychology ◽  
Adaptive Behavior ◽  
Kin Selection ◽  
Evolutionary Biology ◽  
Inclusive Fitness ◽  
Scientific Theories ◽  
Selection Theory ◽  
Inclusive Fitness Theory ◽  
Undergraduate Psychology

Inclusive fitness theory and kin selection theory are among the most recognizable theories associated with evolutionary biology and psychology—they are also among the most widely misunderstood. The problem begins early, in undergraduate psychology textbooks. Here, ten social psychology textbooks were reviewed, and they were all found to contain at least one form of misunderstanding. Because these misunderstandings appear to result partly from people's intuitions about kinship and adaptive behavior (which are not necessarily in line with the scientific theories), writers must be especially vigilant in order to combat the misunderstandings.

Kin Selection

Ecology ◽  
2012 ◽  
Author(s):  
Andrew F. G. Bourke
Keyword(s):  
Natural Selection ◽  
Social Behavior ◽  
Kin Selection ◽  
Inclusive Fitness ◽  
Social Behaviors ◽  
Selection Theory ◽  
Direct Fitness ◽  
Inclusive Fitness Theory ◽  
Gene Copies ◽  
Genetical Theory

According to Hamilton’s kin selection theory (also known as “inclusive fitness” theory), kin selection is the process by which social evolution occurs in nature. The theory extends the genetical theory of natural selection to social behaviors and finds that their evolution is affected by the likelihood that individuals share genes (relatedness). In biology, a social behavior occurs when one individual (the actor) behaves so as to affect the direct fitness (number of offspring) of itself and another individual (the recipient). For example, altruism occurs when the actor’s behavior decreases the actor’s direct fitness and increases the recipient’s direct fitness. Conversely, selfishness occurs when the actor’s behavior increases the actor’s direct fitness and decreases the recipient’s. Social behaviors are widespread in nature. A classic example is the altruism shown by the sterile workers of social insects such as ants, which sacrifice their own reproduction in order to rear the queen’s offspring. At first sight, altruism poses a problem for the genetical theory of natural selection, which seems to preclude the spread of a gene for reduced reproduction. Kin selection was devised by William Hamilton in the early 1960s to address this “problem of altruism.” The basic principle behind kin selection had been hinted at by Darwin, Fisher, and Haldane, but it was Hamilton who provided the first general model. Hamilton called his idea “inclusive fitness” theory, and it was later dubbed “kin selection” by Maynard Smith in 1964. For most purposes, the two can be considered identical, although inclusive fitness theory technically includes kin selection theory because the relatedness it invokes need not involve kin (genealogical relatives). Kin selection theory solved the problem of altruism by showing that a gene for altruism can spread if altruism is directed at individuals likely to bear the same gene. By definition, kin are likely to share genes. So, a gene for altruism can spread if altruism is directed at kin and the loss of gene copies through the actor’s decreased reproduction is more than offset by the gain in gene copies through the increased reproduction of the recipient. The algebraic version of this condition is termed “Hamilton’s rule.” Although kin selection theory was devised to explain altruism, it also applies to the other forms of social behavior such as selfishness. The theory is therefore now widely used to investigate and explain many kinds of social behavior in living organisms as diverse as bacteria and human beings.

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.

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.

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 Kin and multilevel selection in social evolution: a never-ending controversy?

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 776 ◽  
Author(s):  
Jos Kramer ◽  
Joël Meunier
Keyword(s):  
Kin Selection ◽  
Group Selection ◽  
Evolutionary Biology ◽  
Social Evolution ◽  
Selection Process ◽  
Structured Populations ◽  
Multilevel Selection ◽  
Current Debate ◽  
The Relationship ◽  
Shed Light

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.

scholarly journals We were all young once: an intragenomic perspective on parent–offspring conflict

2013 ◽  
Vol 280 (1754) ◽  
pp. 20122637 ◽  
Author(s):  
Benjamin Bossan ◽  
Peter Hammerstein ◽  
Arnulf Koehncke
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Kin Selection ◽  
Life History Traits ◽  
Inclusive Fitness ◽  
Current Debate ◽  
Fitness Effect ◽  
Intragenomic Conflict ◽  
Evolutionary Conflict ◽  
Inclusive Fitness Theory

Parent–offspring conflict (POC) describes the evolutionary conflict between offspring and their parents over parental resource allocation. Offspring are expected to demand more resources than their parents are willing to supply because these offspring are more related to their own than to their siblings' offspring. Kin selection acts to limit these divergent interests. Our model departs from previous models by describing POC as an intragenomic conflict between genes determining life-history traits during infancy or parenthood. We explain why a direct fitness approach that measures the total fitness effect during exactly one generation is required to correctly assess POC in interbrood rivalry. We find that incorrect assumptions in previous models led to an overestimation of the scope of POC. Moreover, we show why the degree of monogamy is more important for POC than previously thought. Overall, we demonstrate that a life-history-centred intragenomic approach is necessary to correctly interpret POCs. We further discuss how our work relates to the current debate about the usefulness of inclusive fitness theory.

scholarly journals Monogamy promotes altruistic sterility in insect societies

2018 ◽  
Vol 5 (5) ◽  
pp. 172190 ◽  
Author(s):  
Nicholas G. Davies ◽  
Andy Gardner
Keyword(s):  
Population Genetics ◽  
Inclusive Fitness ◽  
Stable States ◽  
Genetic Constraints ◽  
Inclusive Fitness Theory ◽  
Insect Societies ◽  
Extended Analysis ◽  
Evolution Of Eusociality ◽  
The Stability ◽  
Worker Sterility

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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