Fig. 4.

Greater costs of resistance. Evolution of the R allele frequency (a), the L allele frequency (b), and the change in the relative population size over time (c). The model is spatial, with release ratio d=20, a strong partially dominant incomplete resistance (${\gamma }_{\mathit{SR}}=0.2$, ${\gamma }_{\mathit{RR}}=0.1$), and costly resistance (${\psi }_{\mathit{SR}}=0.2$, ${\psi }_{\mathit{RR}}=0.1$). Dashed lines indicate the target deme, solid lines indicate the non-target deme, and the line colours indicate the simulated dispersal rate (see legend). Note the longer time scale (2000 generations) than shown in earlier figures. The high-cost resistance goes extinct in both demes; control of the target population is only tempered by immigration from the non-target deme.