Chemistry of fruit-flies. Spiroacetal-rich secretions in several Bactrocera species from the South-West Pacific region

Abstract

The male rectal glandular secretions from the fruit-fly pest species Bactrocera(Notodacus)xanthodes(Broun) and Bactrocera(Bactrocera)kirki(Froggatt) and the non-pest species, Bactrocera(Bactrocera)kraussi(Hardy) are rich in spiroacetals. In B. xanthodes, (5R,7S)-7-methyl-1,6-dioxaspiro[4.5]decane is prominent, whereas in B. kirki(2S,6R,8S)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane is the single major volatile component. B. kraussi, although rich (∼40%) in (2S,6R,8S)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, contains other spiroacetals and a number of compounds that may be biosynthetically related to the spiroacetals. The absolute configurations have been determined by enantioselective syntheses and chiral gas-chromatographic determinations. The results of examinations of Bactrocera(Bactrocera)passiflorae(Froggatt) and Bactrocera(Bactrocera)facialis(Coquillett) are also reported.