THE EVOLUTION OF DISPERSAL IN A METAPOPULATION - A SPATIALLY EXPLICIT, INDIVIDUAL-BASED MODEL

Dispersal is the process that binds the subpopulations of a metapopula tion together. Previous models of the evolution of dispersal have tend ed to be deterministic and not spatially explicit. We develop an indiv idual-based, spatially explicit lattice model to determine how subpopu lation equilibrium density, reproductive rate and form of competition affect the rate of dispersal that is selected for. For comparison, a d eterministic analogue of the individual-based model is also developed. Dispersal rate is a neutral character in the deterministic model. The individual-based model makes predictions which differ significantly f rom its deterministic counterpart, particularly when subpopulation equ ilibrium densities are low. Higher rates of dispersal evolve when repr oductive rate is high and subpopulation equilibrium density is small. Our results demonstrate that the propensity to disperse is not a neutr al character and that deterministic models of metapopulations should b e interpreted with caution.