Indirect genetic effects and the evolution of aggression in a vertebrate system

Abstract

Aggressive behaviours are necessarily expressed in a social context, such that individuals may be influenced by the phenotypes, and potentially the genotypes, of their social partners. Consequently, it has been hypothesized that indirect genetic effects (IGEs) arising from the social environment will provide a major source of heritable variation on which selection can act. However, there has been little empirical scrutiny of this to date. Here we test this hypothesis in an experimental population of deer mice (Peromyscus maniculatus). Using quantitative genetic models of five aggression traits, we find repeatable and heritable differences in agonistic behaviours of focal individuals when presented with an opponent mouse. For three of the traits, there is also support for the presence of IGEs, and estimated correlations between direct and indirect genetic (rA O,F ) effects were high. As a consequence, any selection for aggression in the focal individuals should cause evolution of the social environment as a correlated response. In two traits, strong positive rA O,F will cause the rapid evolution of aggression, while in a third case changes in the phenotypic mean will be constrained by negative covariance between direct and IGEs. Our results illustrate how classical analyses may miss important components of heritable variation, and show that a full understanding of evolutionary dynamics requires explicit consideration of the genetic component of the social environment.

Are flies kind to kin? The role of intra- and inter-sexual relatedness in mediating reproductive conflict

“…Indeed, Saltz [13] reported that the overall aggressiveness of a group of male D. melanogaster is influenced by the genetic composition of that group, or rather, by indirect genetic effects (IGEs). Further evidence for IGEs is provided by Kent et al [46], who report that chemical signalling employed by this species also varies based on the genotypes of neighbours; similar effects of genetic social environment have been documented in mice [47]. Therefore, if genetically determined aggression levels vary within our population, it is possible that social heterogeneity, rather than kinship, may be responsible for the between-treatment variation seen in overall group aggression.…”

Animal personality and state–behaviour feedbacks: a review and guide for empiricists

“…Similarly, the behaviour-predictability feedback is predicted to promote consistency (via a form of correlational selection that favours individuals continuing to do what they have done in the past) in leader-follower situations [45,46] and in contexts of social niche specialization [30]. Other feedback loops involving the reciprocal behaviours of two or more individuals include effects of the aggressiveness of individual X on individual Y and vice versa [47], and personality-dependent, predator-prey behavioural response games [48].…”

Indirect genetic effects and the genetic bases of social dominance: evidence from cattle

“…The l ijk was predicted in a series of four different models accounting for the same fixed effects as above, but considering different partitioning of phenotypic and genetic variance, as suggested by recent literature (Arango et al, 2005;Muir, 2005;Chen et al, 2008;Wilson et al, 2009Wilson et al, , 2011. Different models were as follows:…”