Fig. 4.

Resistance builds up over time when insecticide is sprayed each year on day 50 at the same dose with (a) the default model (see Table 1); (b) the default model parameters except that emergence from an overwintering population is included ($\eta =0.1$), as is movement between the treated and untreated populations (${\iota }_I=0.01$, ${\iota }_E=0.01$).