Figure 4

Dynamics of allele frequencies in n = 4 patches with different costs of resistance and virulence. Patches are characterised by variation of b, u, and s. Patch 1 (red) therefore represents a sub optimal environment for RES plants and avr parasites, while Patch 3 (black) represents an optimal environment for RES hosts and avr parasite as the costs of these alleles are zero. Patches 2 (blue) and 4 (orange) are respectively environment in which only RES and avr alleles are costly. In the four patches, the initial RES frequency is 0.1 and avr frequency is 0.5. The model was run for 1000 generations, and m _H = m _P = 0.05. a) Stable dynamics appear as inward spiralling towards the four different equilibrium points in an infinite deterministic population model. b) Trajectory of allele frequencies for one cycle in each patch, showing irregular, anti-clockwise cycling around the stable equilibrium in a stochastic finite population model (Only the last 200 generations over 1000 are shown).