Resistance to dichlorodiphenyltrichloroethane (DDT) in resistant (91-R) and susceptible (Can-S) Drosophila melanogaster

AGRO 35

Joseph P. Strycharz, jstrycha@vasci.umass.edu and John M. Clark, jclark@vasci.umass.edu. Department of Veterinary and Animal Science, University of Massachusetts, 639 North Pleasant Street, N429 Morrill 1, Amherst, MA 01003
Resistance to dichlorodiphenyltrichloroethane (DDT) in certain Drosophila melanogaster strains is at extremely high levels compared to susceptible strains (>1000 times). Detoxification mechanisms involving, in part, increased expression of cytochrome P450 genes, play a role in DDT resistance but alone do not correlate to the high levels of resistance observed. Resistance in D. melanogaster is due to polyfactorial resistance mechanisms, which include reduced penetration, increased detoxification, and increased excretion. Rates of penetration, metabolism, and excretion were determined between resistant (91-R) and susceptible (Can-S) strains of D. melanogaster using 14C-labeled DDT. Results show that there is ~20% more DDT being metabolized and ~4 times as much DDT being excreted by 91-R compared to Can-S. Differences in cuticular hydrocarbon abundance were determined between 91-R and Can-S, which may result in the penetration differences observed. The abundance of certain hydrocarbons in 91-R flies were between 50-78% greater than in Can-S flies.