title: Competition between fast- and slow-diffusing species in non-homogeneous environments.
abstract: We study an individual-based model in which two spatially distributed species, characterized by different diffusivities, compete for resources. We consider three different ecological settings. In the first, diffusing faster has a cost in terms of reproduction rate. In the second case, resources are not uniformly distributed in space. In the third case, the two species are transported by a fluid flow. In all these cases, at varying the parameters, we observe a transition from a regime in which diffusing faster confers an effective selective advantage to one in which it constitutes a disadvantage. We analytically estimate the magnitude of this advantage (or disadvantage) and test it by measuring fixation probabilities in simulations of the individual-based model. Our results provide a framework to quantify evolutionary pressure for increased or decreased dispersal in a given environment.
authors.affiliation: Departament de Fisica, Universitat Politecnica de Catalunya Edif. GAIA, Rambla Sant Nebridi 22, 08222 Terrassa, Barcelona, Spain. Electronic address: simone.pigolotti@upc.edu.
authors.forename: Simone
authors.initials: S
authors.lastname: Pigolotti
authors.affiliation: Dipartimento di Fisica, Universitá di Roma "Tor Vergata" and INFN, via della Ricerca Scientifica 1, 00133 Roma, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Benzi
mesh_terms: D005075:Biological Evolution; D017753:Ecosystem; D008954:Models, Biological
keywords: Evolution of dispersal; Individual based models; Optimal dispersal strategy; Reaction-diffusion models; Spatial population genetics