Fig. 2.

The dependence of σ₁ and σ₂ on the strategy mutation rate, μ. We choose M = 100 sets and show different values of the set mutation rate: (A) ν = 0, (B) ν = 3, (C) ν = 10, (D) ν = 100, (E) ν = 1,000, and (F) ν = ∞. We observe that σ₂ ∼ μ. For ν → 0 and ν → ∞ we obtain the same behavior, because both cases correspond to a well-mixed population. For a particular strategy mutation rate, μ*, we have σ₁ = σ₂. For μ < μ* structural effects prevail over mutation, because σ₁ > σ₂. For μ > μ* mutation destroys the effect of population structure, because σ₁ < σ₂.