Adaptive Evolution of Virulence-Related Traits in a Susceptible-Infected Model with Treatment
Figure 1
Pairwise invasibility plots. The resident and mutant strategies are denoted by and , respectively. The shaded areas marked with “+” indicate the combinations of and for which the fitness of the mutant, , is positive. Arrows indicate the direction of disruptive selection which implies convergent stability. Black bullet = evolutionarily stable singular strategy, red bullet = evolutionary branching point, and blue bullet = repeller. (a) Only one singular strategy is a CSS when ; (b) only one singular strategy is an evolutionary branching point when ; and (c) multisingular strategies . Model parameters: , , , , , , , and .