How Should We Define Fitness in Structured Metapopulation Models? Including an Application to the Calculation of Evolutionarily Stable Dispersal Strategies.

We define a fitness concept applicable to structured metapopulations consisting of infinitely many equally coupled patches, and provide means for calculating its numerical value. In addition we introduce a more easily calculated quantity RM that relates to fitness in the same manner as RO relates to fitness in ordinary population dynamics: RM of a mutant is only defined when the resident population dynamics converges to an equilibrium, and RM is larger (smaller) than one if and only if mutant fitness is positive (negative). RM corresponds to the average number of newborn dispersers resulting from the (on average less than one) local colony founded by a newborn disperser. As an example of the usefulness of these concepts we calculate the ES conditional dispersal strategy for individuals that can account for the local population density in their dispersal decisions.