Modelling movement and stage-specific habitat preferences of a polyphagous insect pest

The feeding preferences of Diabrotica speciosa (Coleoptera: Chrysomelidae) cause a parent-offspring conflict, as providing the best host for the offspring development is detrimental to adult survival and fecundity. Understanding the implications of this conflict could help entomologists to implement pest-management programs. With this in mind, the foraging behaviour of D. speciosa was investigated using an individual-based model in two distinct scenarios. In the first scenario, parent-offspring conflict was analysed when adult insects move in a strip intercropping system, exploiting two crops that provide different nutritional advantages for each insect stage (immature and adult). In our simulations, we found an optimal foraging time, which was influenced mainly by the width of the crop rows. We also investigated the effects of a “mother knows best” strategy on population dynamics, and found that the rate of population growth changes when this strategy is adopted. In the second scenario, simulations were run for different spatial configurations and crop calendars. We observed that including fallow areas and adopting a more-heterogeneous arrangement of crops in the landscape could reduce the levels of this insect pest. This study provides important information about the effects of differences in food suitability between the larval and adult stages on the spatial dynamics of D. speciosa, and on the decision-making process for the implementation of integrated pest-management plans.