The social context of life history evolution

We discuss ways in which the social environment as individual inhabits may have influenced, and continues to influence, the lift history patterns it f ollows. We argue that the social context in which a life history is express ed has the potential to influence the evolution of that life history in fou r distinct ways, and that these may not always have been fully considered i n classic life history theory. First, conflicts of interest are frequent wh en non-clonal organisms interact. and this is particularly true for reprodu ction, where conflicts between the sexes and between parents and offspring have numerous potential impacts on life histories. Second, the occurrence o f frequency- and density-dependent selection arising from social interactio ns can have important consequences for predicting the evolutionary trajecto ries of life histories. Third, research in sexual selection has often been free of a life-history perspective: combining the two has the potential to offer interesting insights into the process of sexual selection and the evo lution of sexual ornamentation, Finally, we illustrate some of the more dra matic outcomes of these factors for life history evolution by discussing th e evolution and maintenance of within population polymorphisms in life hist ories. An appreciation of the roles of social interactions may provide a so lution to some long-standing questions in life-history research, such as ho w high levels of additive genetic variance for traits closely related to fi tness are maintained.