Figure 3.

Asymptotic level of cooperative investment after 100 000 generations as a function of dispersal rate d, for a population of 500 individuals, subdivided into 100 interaction groups. (a) k=2; (b) k=3. In both cases, there exists a region of dispersal values for which high levels of cooperative investment evolve, and are maintained indefinitely. We note that cooperation breaks down both at high d and at very low (but non-zero) values of d. Results shown are from 10 replicate simulations; initial investments were chosen uniformly randomly between 0 and 0.5. All other parameters as in figure 1.