Donald Price and Elizabeth Stacy (Life Sciences), along with a previous graduate student and colleagues from the USDA-ARS in Hawaii and at Eastern Mennonite University, published an article in the March issue of Scientific Reports titled "Phenotypic Disruption of Cuticular Hydrocarbon Production in Hybrids Between Sympatric Species of Hawaiian Picture‑wing Drosophila." Using gas chromatography mass spectrometry they investigated the differences in cuticular hydrocarbon (CHCs) production between two Hawaiian picture-wing Drosophila species, Drosophila heteroneura and D. silvestris, and their F1 and backcross hybrid offspring.
CHCs are long-chain carbon molecules that occur on insect cuticles and are known to provide resistance to desiccation and act as pheromones for mating. CHC profiles differed between males of the two species, with substantial sexual dimorphism in D. silvestris but limited sexual dimorphism in D. heteroneura. Surprisingly, F1 hybrids did not produce three of the CHCs, and the abundances of several other CHCs occurred outside the ranges present in the two parental species. Variation in CHCs in backcross hybrids was greater than that observed in F1 or parental species. Overall, these results indicate that the production of CHCs was disrupted in F1 and backcross hybrids, likely due to disruption in the biochemical and gene expression coordination networks involved in CHC production. These results have important consequences for the survival and reproduction of hybrid individuals and could contribute to reproductive isolation and speciation in these insects.
