EFFECT OF PLANTS ON THE SEARCHING EFFICIENCY OF A GENERALIST PREDATOR- THE IMPORTANCE OF PREDATOR-PREY SPATIAL ASSOCIATION

In most studies of tritrophic interactions, the effect of plants on pr edators is confounded with changes in prey and predator behaviors afte r an encounter event. Here, we estimate how the effect of plants on pr ey distribution (in the absence of the predator) and on predator forag ing behavior (in the absence of prey) may influence predation rate of Orius insidiosus (Say) (Heteroptera: Anthocoridae) in 11 plant by prey species combinations. The within-leaf distributions of O. insidiosus and its prey overlapped most on bean plants. The predator's foraging b ehavior (e.g., walking speed, turning rate) also differed among plant species. Simulations, using the prey distribution data and predator's foraging patterns on leaf surfaces of each plant species, show that, o verall, the searching efficiency of O. insidiosus was higher on leaves of bean and corn than of tomato. However, the predator's searching ef ficiency was not consistent within plant species. Thus, the combined e ffect of plants directly on the predator and indirectly through the pr ey influenced the predator's searching efficiency.