Plots showing examples of the range of behaviour attainable from population dynamics models of engineered underdominance and killer-rescue gene drive systems with early-acting lethals.

Here the top row of panels ((a)-(c)) show effects in the engineered underdominance system whereas the bottom row ((d)-(f)) demonstrate effects in the killer-rescue system. Columns display different degrees of density dependence. From left to right these are weak overcompensatory ((a) and (d), β = 1.1); intermediate overcompensatory ((b) and (e), β = 2.75); and strong overcompensatory ((c) and (f), β = 3.5) dynamics. Initial wild-type adult population sizes with these strengths of density dependence are ∼309 (for β = 1.1), ∼104 (for β = 2.75) and ∼89 (for β = 3.5). For β = 1.1 the system displays stable dynamics whereas for β = 2.75 and β = 3.5 we see oscillatory dynamics that are damped and neutral, respectively. Assuming the cargo (refractory) gene is fully effective in a single copy, it is important to consider here the number of wild-type mosquitoes (solid black lines) relative to all others since these are the only genotype in which females are capable of transmitting viruses. Note here the differences in scaling of both the x and y axes.