Invasion of Fitness-Associated Dispersal. FAD invaded a population with a uniform dispersal rate throughout the parameter range tested (p ≤ 10-10 for each parameter set, exact binomial test), even though the average dispersal rate of the FAD and uniform subpopulations was held equal in each simulation (α
). The figure shows the mean number of generations required for a FAD allele to increase in frequency from 0.01 to 0.8 in the cases where FAD took over the population (cells’ clarity increases with number of generations), for different values of the mean dispersal rate α (A: α = 0.01, B: α = 0.1, C: α = 0.3). As the cost of dispersal increases the relative advantage of fit FAD individuals that rarely disperse increases and it takes FAD less time to spread. As the average rate of dispersal increases (from panel A to C), FAD takeover occurs more rapidly when the dispersal cost is high, and more slowly when it is low. The effect of the dominance coefficient h was notable mostly at high dispersal rates together with low dispersal cost, where the number of heterozygotes was highest. Parameters: N ≥ 900 for α = 0.01; N ≥ 100 for all other values of α.