title: Evolutionary branching in deme-structured populations.
abstract: Adaptive dynamics shows that a continuous trait under frequency dependent selection may first converge to a singular point followed by spontaneous transition from a unimodal trait distribution into a bimodal one, which is called "evolutionary branching". Here, we study evolutionary branching in a deme-structured population by constructing a quantitative genetic model for the trait variance dynamics, which allows us to obtain an analytic condition for evolutionary branching. This is first shown to agree with previous conditions for branching expressed in terms of relatedness between interacting individuals within demes and obtained from mutant-resident systems. We then show this branching condition can be markedly simplified when the evolving trait affect fecundity and/or survival, as opposed to affecting population structure, which would occur in the case of the evolution of dispersal. As an application of our model, we evaluate the threshold migration rate below which evolutionary branching cannot occur in a pairwise interaction game. This agrees very well with the individual-based simulation results.
authors.affiliation: Meiji Institute for Advanced Study of Mathematical Sciences, Meiji University, Tokyo 164-8525, Japan; Japan Science and Technology, PRESTO, Japan. Electronic address: joe@meiji.ac.jp.
authors.forename: Joe Yuichiro
authors.initials: JY
authors.lastname: Wakano
authors.affiliation: Department of Ecology and Evolution, UNIL Sorge, Le Biophore, 1015 Lausanne, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Lehmann
mesh_terms: D000465:Algorithms; D000818:Animals; D005075:Biological Evolution; D005716:Game Theory; D040961:Genetic Drift; D008957:Models, Genetic; D009154:Mutation; D011156:Population Density; D011157:Population Dynamics; D012641:Selection, Genetic
keywords: Genetic drift; Hamilton׳s rule; Inclusive fitness effect on trait variance; Individual-based simulation; Relatedness