Figure 4.

Maintenance of genomic diversity for different between‐individual selection pressures. The results of the AM Fungi Simulation model are plotted, showing the level of genomic diversity maintained within individuals at equilibrium (E[z*]). The heat maps plot the full range of between‐individual selection, from decelerating to accelerating returns on plant specialization (α, y‐axis), and from a plant 2 to a plant 1 dominated environment (p, x‐axis). Nucleus 1 has a replicative advantage (r ₁ = 0.305, r ₂ = 0.3), meaning (a) genomic diversity is favored in environments that are slightly dominated by plant 2, which the slower replicating nucleus is specialized on (m = 0, f = 0.005). (b) As sporulation stochasticity is increased (small spores), more genomic diversity is stable across the between‐individual selection parameter space (f = 0.01). (c) Fusion of individuals destabilizes genomic diversity over most of the parameter space at equilibrium (m = 0.05). (d) The counteracting effects of fusion and sporulation stochasticity can cancel each other out (f = 0.01, m = 0.05). These results assumed n = 2,000 (population size), d = 0.5 (dispersal)