Figure 9

Simulated co-evolution of the virulence of with two co-infections, constructed for the parameters \(\beta _{01}=\beta _{02}=0.21\), \(K_1=0.47\) and \(K_2=0.48\). The dark green regions represent the domains for which \(I_1=0\) but \(I_2\ne 0\), the yellow domains represent the domains for which \(I_1\ne 0\) but \(I_2=0\) and finally, the light green regions represent the coexistence domains (\(I_1\ne 0\), \(I_2\ne 0\)). The solid lines show the dependence of the Evolutionary Stable Strategy (\(\alpha _2\)) on the virulence \(\alpha _S^*\) of parasite type 1 (\(I_1\)) and vice versa. The dashed lines represent the ESS in the absence of \(I_1\) (or \(I_2\)). The dotted curve represents an example of the evolutionary trajectory with evolutionary suicide (see Fig. 10). The Adaptive Dynamics based evolution is governed by the surviving strains subsequent to the long term simulations following the invasion by rare nearby mutants. All other model parameters are as defined in Table 1.