The evolutionary potential of cooperation (M) was computed by combining the final proportion of cooperators and the rate of fixation of either strategy. The M score was significantly influenced by the benefit to defect (b), the average duration of pre-reproductive, reproductive, and post-reproductive life span, as well their interactions. To illustrate the main findings, average M for each scenario is plotted as a function of the pre- and post-reproductive lifespans for separate b values (increasing from left to right) and for the shortest (top row) and longest (bottom row) reproductive duration.