Discrimination in mate selection is a crucial step leading to speciation. Selection in insects is guided by hydrocarbon pheromones located on their exterior cuticle, which is coated with a complex mixture of straight-chain saturated, unsaturated, and branched hydrocarbons.In Drosophila, cuticular hydrocarbons are among factors known to act as sexual signals. Unique species-specific profiles enable recognition among individuals of the same species. Drosophila athabasca, found widely throughout Northern America, is in the process of speciation, with three distinct behavioral races; WestNorthern found primarily in Canada and Alaska and two Eastern races, A and B. These races are morphologically similar; however, an overall pattern of sexual isolation exists among them. This discrimination in mate selection makes D. athabasca an excellent model for nascent speciation. We hypothesize that cuticular hydrocarbon profiles of the D. athabascaraces are critical to sexual discrimination and thus speciation.Investigating the unique cuticular hydrocarbon profiles of the D. athabasca races provides insight to the biochemical factors influencing sexual isolation. We have characterized D. athabasca cuticular hydrocarbons using GC-MS analysis of individuals from several isofemale lines. The cuticular hydrocarbons were identified using mass spectrometry analysis and confirmed by comparison with available analytical standards or synthesized compounds. Dimethyl disulfide (DMDS) derivatizations were used to unambiguously identify sites of unsaturation. The most abundant cuticular hydrocarbons of WestNorthern and Eastern A races were synthesized. Synthesis of monounsaturated cuticular hydrocarbons was achieved by cis-directed Wittig reactions. Geometric isomers were separated by flash chromatography and HPLC methods. Dienes were synthesized by coupled substitution reactions of deprotonated acetylenes followed by cis-selective reduction.

Identification, characterization, and synthesis of<i> Drosophila athabasca</i> cuticular hydrocarbons

247th National Meeting (2014)

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Identification, characterization, and synthesis of Drosophila athabasca cuticular hydrocarbons