Fig. 2: Coevolution from antagonism to mutualism in one-plant species communities.

Panels (a, b) show interaction outcomes as a function of attraction (v_i) and defense (h_max − h_i), where h_max is the maximum herbivory rate (Methods). Parameter space regions depict ecological outcomes and arrows highlight coevolutionary effects. The ancestral insect persists as a pure antagonist above the dashed gray line (Eq. 1) and is extinct below. Co-option of the antagonist as a pollinator and the evolution of pollination benefits (b_i > 0) expands the green mutualistic region by moving the interaction breakdown boundary (Eq. 3; solid black line) away from the interaction transition boundary (Eq. 2; dotted black line), as depicted by the green arrows (see Supplementary Movies 1 and 2). The insect persists as a net antagonist despite being co-opted as a pollinator within the gray regions and goes extinct within the white regions. Simultaneous to the evolution of pollination benefits, coevolution of attraction and defense drives the transition to net mutualism, as depicted by the orange arrows pointing from the ancestral coESSs (white points) to the new coESSs (black points). Empirical estimates of the coESSs are not included here (as in Fig. 3) due to data limitations. Panels (c, d) plot the equilibrium densities of each plant species (solid green lines) and insect larvae per plant of each Datura species (dashed green lines) over evolutionary time, τ. Panels (e, f) plot the coevolutionary dynamics of pollination benefits (b_i; black lines), attraction (v_i; blue lines), and defense (h_i; purple lines).