INFLUENCE OF OVARY AND ECDYSTEROIDS ON PHEROMONE BIOSYNTHESIS IN DROSOPHILA-MELANOGASTER (DIPTERA, DROSOPHILIDAE)

The influence of ovary and ecdysteroids on pheromone biosynthesis was investigated in D. melanogaster. Strains mutant for ovo produced enhan ced amounts of cuticular hydrocarbons in both sexes. Female sex pherom one production was not affected by the mutation, except homozygous fem ales for ovo(Dlrsl) which exhibited a higher proportion of the pheromo ne, 7,11 heptacosadiene. The amount of hydrocarbons in wild-type (CS) flies was stable at 21 and 25 degrees C but dramatically increased at 29 degrees C whereas the cuticular hydrocarbon pattern was unchanged. In contrast, ecdysone-less I-ls (ecd-I) flies showed an increase in ov erall hydrocarbon production at both permissive and restrictive temper atures. At restrictive temperature they showed also a decrease in pher omonal dienes production for females with an increase in monoenes and an inversion of the 7 tricosene-7 pentacosene ratio for males. These e ffects were partially reversible since a switch from 29 to 21 degrees C restored an intermediary hydrocarbon pattern. It is suggested that t he regulation of female sex pheromone might be under the control of th e ecd-I gene.