Co-evolution and plant resistance to natural enemies

Co-evolution between plants and their natural enemies is generally believed to have generated much of the Earth's biological diversity. A process anal ogous to co-evolution occurs in agricultural systems, in which natural enem ies adapt to crop resistance introduced by breeding or genetic engineering. Because of this similarity, the investigation of resistance mechanisms in crops is helping to elucidate the workings of co-evolution in nature, while evolutionary principles, including those derived from investigation of co- evolution in nature, are being applied in the management of resistance in g enetically engineered crops.