A major challenge for ecologists is to understand the ecological and evolutionary mechanisms that create differences between and within species in naturally complex environments. Individuals of different species interact in local communities and can influence each other both directly, or indirectly through intermediaries. This is particularly true for the interactions among plants, insect herbivores that feed on these plants and the natural enemies of these herbivores (predators and parasitoids). Plant characteristics, such as chemical compounds not only strongly affect the performance of the herbivores, but also the performance of the natural enemies that feed on these herbivores. Furthermore, by feeding on a plant, an insect can induce the production of chemical defenses that will affect the performance of other herbivore species that feed on the same plant and of the natural enemies of these herbivores. We are testing these ideas using a natural system that comprises several species of bean plants (wild and cultivated), seed beetles that feed on the beans, and the parasitoids that develop on the larvae of these beetles. Using a highly multidisciplinary approach comprising of manipulative laboratory and field studies, this project should provide us insight into how direct and indirect interactions between insects species in natural communities affect the evolution of complex communities. In addition to this fundamental importance the study has potential for application in the development of pest control strategies. Beans are an important staple food and seed beetles can be devastating pest insects, not only on beans, but on many other cultivated grains, especially in storage situations. Adding to the knowledge of how different members of a natural community interact might help in the development of methods to better protect the beans and grains against insect pests.