Ecological theory predicts that predation in a given location will be stronger than expected when predator populations are supported by resources outside that location (e.g., alternative species of prey). This is because external resources may allow predator populations to build even though local resources are scarce. This situation can occur when mobile predators frequently move between different habitats. Movement between multiple habitats allows predators to use resources both within and outside of a prey's habitat, allowing their populations to build (even if local conditions are bad) and strongly suppress prey.
Despite its theoretical importance, there has been little research in terrestrial habitats investigating the influence of predator movement on the intensity of predation in local habitat patches. This research will examine the question experimentally by decreasing and increasing movement of predators between crop habitats and native prairie grass; the investigators will then observe the resulting impact on predation within crops. The goal is to determine if natural areas outside of crops provide resources that enhance predation on insect pests within a crop habitat. If this is the case, restoring natural areas in agricultural landscapes could reduce the need to use insecticides to control pests.
