Figure 2. Representation of fluxes in the x-direction in the spatial simulation model.

N (x,y,t) is the density of beetles (m⁻²) in a grid cell with coordinates (x,y) at time t. μ ₁ and μ₂ (m² d⁻¹) are the motilities of beetles in oilseed radish and rye, respectively. π ₁ and π ₂ are dimensionless and modify the fluxes of beetles between the two habitats.