Formal model for Acyrthosiphon pisum, Aphis fabae, Myzus persicae and Sitobion avenae using the ALMaSS subpopulation approach

Aphids are one of the most harmful insect species for crops and are thus an important group to model in ALMaSS because they drive both management and natural enemy dynamics. Due to the enormous number of aphids, using an agent-based method to model aphids is not feasible. To deal with this, we propose creating an Aphid model using a spatial subpopulation model approach. Built on the dynamic landscape model in ALMaSS, subpopulations are assumed to occupy the landscape in a set of regular grid cells of equal size. The aphid population will be tracked in each grid using a stage-structured population model; population size and behaviour will depend on the habitat structure under the grid. They will develop, reproduce, and die based on the aphids’ physiological processes, the effects of predators, and the grids’ weather and vegetation host conditions. Aphid dispersal by flying and local movement to adjacent grids will interconnect the populations in the grid cells.