title: Selective advantage of diffusing faster.
abstract: We study a stochastic spatial model of biological competition in which two species have the same birth and death rates, but different diffusion constants. In the absence of this difference, the model can be considered as an off-lattice version of the voter model and presents similar coarsening properties. We show that even a relative difference in diffusivity on the order of a few percent may lead to a strong bias in the coarsening process favoring the more agile species. We theoretically quantify this selective advantage and present analytical formulas for the average growth of the fastest species and its fixation probability.
authors.affiliation: Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya Edifici GAIA, Rambla Sant Nebridi 22, 08222 Terrassa, Barcelona, Spain.
authors.forename: Simone
authors.initials: S
authors.lastname: Pigolotti
authors.affiliation: Dipartimento di Fisica, Universita' 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: D003163:Competitive Behavior; D004058:Diffusion; D017753:Ecosystem; D008954:Models, Biological; D011157:Population Dynamics; D013269:Stochastic Processes