Figure 1.

Dynamics of a population consisting of (a) O_C and AllD, (b) AllD and O_D, (c) O_C and O_D (resp.). Black circles represent Nash equilibria, white circles indicate unstable fixed points. The arrows on the edges indicate the direction of the dynamics if only the two strategies corresponding to the endpoints are present. The orange grid is the manifold that separates initial values with different asymptotic behaviour. The blue curves represent the typical dynamics for a given initial population. Parameter values: b = 4, c = 1, β = γ= 2 and μ = 30 per cent (hence γ/(2b) < μ< γ/(γ + b)).