Fig. 8.

Introducing minor costs of dominant, complete 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, and a dominant complete resistance (${\gamma }_{\mathit{SR}}={\gamma }_{\mathit{RR}}=0$) with minor costs (${\psi }_{\mathit{SR}}=0.95$, ${\psi }_{\mathit{RR}}=0.85$). Dashed lines indicate the target deme, solid lines indicate the non-target deme, and the line colours indicate the simulated dispersal rate (see legend). Greater influx of L alleles through dispersal into the non-target deme selects for a large increase in the frequency of resistance. This causes the non-target deme to become a source of R alleles for the target deme, which decreases the effectiveness of target population suppression.