1. Introduction
In agricultural systems, knowledge of food web interactions is often limited due to the complexity of tri trophic relationships and the number of species involved (Basco mpte and Melian, 2005).
Invasions of exotic species are likely to profoundly affect the structure of food webs in
agroecosystems. The soybean aphid,
Aphis glycines
Mat-
sumura, a native of Asia, was
W
rst detected in the U.S. in
Wisconsin in July of 2000. Its range now extends through-