behaviour: a synthetic model. Nature 318, 366-367. [125] Riley, J.G., 1979. Evolutionary equilibrium strategies. J. Theor. Biol. 76, 109-123. [126] Riolo RL, Cohen MD, Axelrod R, 2001. Evolution of cooperation without reciprocity. Nature, 418, 441-443. [127] Rousset, F., 2004. Genetic structure and sele