LOCAL ADAPTATION AND GENE-FOR-GENE COEVOLUTION IN A METAPOPULATION MODEL

In several reciprocal cross-infection experiments parasites were found to be significantly more adapted to their local host populations than to hosts from distant populations. We developed a metapopulation mode l, taking explicit account of both population densities and gene frequ encies, to determine the influence of ecological and genetical paramet ers on the local adaptation of the parasites and on the spatial distri bution of resistance and virulence genes. Our results point to the pre dominant effect of ecological parameters such as parasite growth rate and host and parasite migration rates on coevolutionary outcomes. In p articular, the parasites are more likely to be adapted to their local host population than to allopatric hosts when the parasite migration r ate is larger than the host migration rate. The opposite should be obs erved whenever hosts migrate more than parasites.