How many genetic options for evolving insecticide resistance in heliothine and spodopteran pests?
Bottom Line: The widely accepted paradigm for the development of insecticide resistance in field populations of insects is of selection for one or a very few genes of major effect.We discuss possible explanations for this paradox, including the likely embedding of these genes in regulatory cascades and emerging evidence for their arrangement in large clusters of closely related genes.We conclude that there could indeed be an unusually large number of genetic options for evolving resistance in these species.
Affiliation: CSIRO Ecosystem Sciences, 1700 Canberra ACT 2601, Australia. firstname.lastname@example.orgShow MeSH
Related in: MedlinePlus
Mentions: The biochemical work on the esterases has gone a step further because of the facility of separating and staining individual esterase enzymes on native PAGE gels. The esterase isozyme profiles of the leipdopterans under discussion here are found to be considerably more complex than those of the dipteran and hemipteran precedents above. For example, Campbell30 found over 30 distinct isozymes in fourth instar H. armigera larvae alone, with several others also evident in other life stages of this species. Moreover greater staining intensities of several of the isozymes (6–9 in some cases) have been associated with OP or SP resistances in H. armigera,12,31,32H. punctigera,33H. virescens,27S. littoralis,34S. litura35 and S. exigua.36Figure 1 shows that at least four regions of the esterase zymogram, each containing multiple isozymes, have been associated with OP and pyrethroid resistance in H. armigera.12,30,32,37,38
Affiliation: CSIRO Ecosystem Sciences, 1700 Canberra ACT 2601, Australia. email@example.com