ABSTRACT

It is impossible to discuss the issues involved in the phenomenon of resis­ tance without dealing with the various terms, as they often mean different things to different people, even nuances of terms change their meanings. For example, many researchers discuss the “development” of resistance. Resistance does not “develop” as they state, as it is not a developmental phenomenon, nor is it studied by developmental biologists, who study how an organism develops, not how a species evolves. Resistance is an evo­ lutionary phenomenon. Resistance appears as a result of the selection of pre-existing and continually occurring rare mutant genotypes that allows the evolution of populations under the pressure of the selecting herbi­ cide. Resistance does not appear as a result of a Lamarkian adaptation. Thus, the terms “development” and “adaptation” should be eschewed in the context of resistance. Pesticide resistance has long been recognized as one of the clearest examples of evolution occurring in modern times. Even though most research on pesticide resistance has emphasized its implications for pest management, resistance is also an excellent tool for basic research on population biology and for the molecular study of evolu­ tion because the causes and history of selection can be relatively easily identified.1219