GENETIC-CONTROL OF MALE CUTICULAR HYDROCARBONS IN DROSOPHILA-MELANOGASTER

7-tricosene (7-T) and 7-pentacosene (7-P) are the two main hydrocarbon s on the cuticle of male Drosophila melanogaster. These two substances might play a pheromonal role during courtship behaviour. We investiga ted the genetic basis of the quantitative polymorphism observed in the production of 7-T and 7-P. Strains of different geographic origin, wi th males producing either predominantly 7-T or predominantly 7-P, were hybridized with strains carrying genetic markers. We found that chrom osome II changes the balance between 7-T and 7-P while chromosome III regulates the overall quantity of both 7-monoenes. We have also charac terized and roughly mapped sept and smog, two genetic factors on chrom osome II that act additively on the production of both cuticular hydro carbons. The genetic control of the variation in 7-T and 7-P varies be tween D. melanogaster strains and between D. melanogaster and its sibl ing species D. simulans. The possible evolutionary and physiological c auses of this variation as well as its functional implication for cour tship behaviour are discussed.