American Journal of Alternative Agriculture

Articles

Ecological genetics and evolution in insect pests: Implications for lower input agriculture

Ellen L. Simmsa1

a1 Assistant Professor, Department of Biology, Wake Forest University, Winston-Salem, NC 27109.

Abstract

This paper has three goals: (1) to convince ecologists and evolutionary biologists to study the evolution in insects of the ability to overcome crop protection measures, (2) to provide insights into the kinds of data needed to develop methods for retarding the evolution of such traits, and (3) to suggest that the study of these phenomena can further our understanding of evolution. The evolution of resistance to chemical insecticides often results in higher application rates and constant development of new classes of these potentially environmentally degrading toxicants. Moreover, it is important to understand resistance phenomena related to alternative crop protection measures involving plant genetic resistance and biological insecticides so that these less environmentally damaging control measures can be maintained. Insecticide resistance evolves in insect populations in response to selection by chemical compounds. Similarly, selection by host-plant defenses of resistant crops leads to the evolution of virulence to those varieties. The evolution of these traits constitutes an important subject of applied evolutionary biology. In the context of single-gene evolutionary models, this article reviews the most common strategies that have been suggested for retarding the evolution of insecticide resistance. These models are also used to illustrate the effects of ecological factors and genetical properties of insect populations on the evolution of resistance. Where appropriate, the relevance of these models to the evolution of virulence to resistant crop varieties is also described. Durability in the insecticidal effectiveness of a plant protective chemical is not incompatible with the requirement for health safety in the same material.