Fig. 5.

These plots show the absolute value of the relative difference between the velocity of the front predicted by hybrid simulations and full stochastic age-dependent SSA simulations (plot (a)) and the coarse-grained mean-field system (plot (b)). The green solid line represents the mean value over time. Each point corresponds to an average over 40 realisations of the age-structured SSA and 100 realisations of the hybrid method. The velocity of the front is calculated using the data corresponding to the position of the (average) front shown in Fig. 4. The threshold, Θ, in the hybrid simulations is taken to be Θ = 2000. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)