MODELING THE ROLE OF HOST-PLANT DISPERSION IN THE SEARCH SUCCESS OF HERBIVOROUS INSECTS - IMPLICATIONS FOR ECOLOGICAL PEST-MANAGEMENT

Routine planting decisions made by farmers and foresters appear to hav e a direct impact upon attack frequencies by herbivorous insect pests. To what extent are these frequencies affected by 'habitat architectur e' variables, such as host plant dispersion, density and abundance? Ho w might such patterns shift for herbivore species that differ in searc h strategy (e.g. via turning rate differences)? We address these quest ions through simulation and analytical modelling. Simulations of two t ypes 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 specie s with differing search parameters. For simple cases, analytical confi rmations of simulation results are obtained. Significant differences i n 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 plant s within patches, and (iv) radial distance of detection of host by ass ociated herbivore. Combined with field experimentation, such simulatio ns can offer insight into habitat-scale processes underlying host plan t-herbivore interactions.