Alcohol tolerance and alcohol utilisation in Drosophila: partial independence of two adaptive traits

Three natural populations of D. melanogaster with different ethanol tolerance, and a population of D. simulans were successfully selected for an increased capacity to withstand alcohol. Alcohol utilisation, measured by the increase of life duration in the presence of low concentrations of alcohol, was clearly improved only in two cases. Alcohol tolerance and utilisation, two physiological traits that both depend on the presence of an active ADH, are thus controlled, at least partly, by different genetic mechanisms. In Drosophila species breeding on fermenting fruits or in wine cellars, both traits may be under the control of natural selection.