Modelling the role of host plant dispersion in the search success of herbivorous insects: Implications for ecological pest management

Abstract

Routine planting decisions made by farmers and foresters appear to have a direct impact upon attack frequencies by herbivorous insect pests. To what extent are these frequencies affected by ‘habitat architecture’ variables, such as host plant dispersion, density and abundance? How might such patterns shift for herbivore species that differ in search strategy (e.g. via turning rate differences)? We address these questions through simulation and analytical modelling. Simulations of two types are conducted. First, individual search trajectories are imposed upon differing habitat arrays of host plants. Second, initial release distances to nearest host plants are varied for model herbivore species with differing search parameters. For simple cases, analytical confirmations of simulation results are obtained. Significant differences in probability of host plant attack emerged as functions of (i) overall dispersion of plants within foraging habitats (patches), (ii) density of plants within patches, (iii) specific location of individual plants within patches, and (iv) radial distance of detection of host by associated herbivore. Combined with field experimentation, such simulations can offer insight into habitat-scale processes underlying host plant-herbivore interactions.