The Genetic Basis of Resistance to Diazinon in Natural Populations of Drosophila melanogaster

Isofemale strains of Drosophila melanogaster were established from single inseminated females collected from populations along the east coast of Australia. Strains were tested for resistance to the organophosphorus insecticide diazinon at larval and/or adult stages of the life cycle. Considerable phenotypic variation was observed within and between population samples but there was no association between collection site of a sample and resistance status. Adult and larval resistance levels were uncorrelated. Resistance levels in adults were low (2-fold) and polygenically based. Larval resistance levels, due to single genes (or gene complexes) on chromosomes II and III, were significant (15-fold). Evidence indicates that the gene on chromosome II is Cyp6g1.