Table 1.

Summary of the effects of different parameters on the evolution of mutualism

Increase of parameter	Effect on initial spread and persistence
Population (lattice) size	positive (cf. Fig. 4)
Number of mutualistic interactions (iterations) per generation	positive
Maximum benefit B0	positive (cf. Fig. 4)
Unit cost C0	negative (cf. Fig. 4)
Vertical transmission	positive
Nonlocal dispersal	negative
Stochasticity in contest	positive (cf. Figs. 3B and 4)
Stochasticity in payoff	positive (cf. Figs. 3D and 4)
Asymmetry in generation time	negative (cf. Fig. 3C)
Asymmetry in mutation rate or magnitude	negative

The robustness of these patterns was confirmed by hundreds of simulations by using a variety of baseline conditions.