The cuticular hydrocarbons of the Triatoma sordida species subcomplex (Hemiptera: Reduviidae)

Abstract

The cuticular hydrocarbons of species of the Triatoma sordida subcomplex (Hemiptera: Reduviidae: Triatominae) were analyzed by gas chromatography, and their structures identified by mass spectrometry. They comprised mostly n-alkanes and methyl-branched alkanes with 1 up to 4 methyl substitutions. n-Alkanes consisted of a homologous series from C21 to C33, and represented 33% to 45% of the hydrocarbon fraction; n-C29 was the major component. Methyl-branched alkanes showed alkyl chains from C24 to C43. High molecular weight dimethyl and trimethylalkanes (from C35 to C39) represented most of the methyl-branched fraction. A few tetramethylalkanes were also detected, comprising mostly even-numbered chains. Several components such as odd-numbered 3-methylalkanes, dimethylalkanes and trimethylalkanes of C37 and C39 showed patterns of variation that allowed to differentiate the species and populations studied. T. guasayana and T. patagonica showed the most distinct hydrocarbon pattern within the subcomplex. The T. sordida populations from Brazil and Argentina showed significantly different hydrocarbon profiles that posed concerns on the homogeneity of the species. T. garciabesi had the more complex hydrocarbon pattern, but it shared some similarity with T. sordida. The quantitative and qualitative variations in the cuticular hydrocarbons may help to elucidate the relationships between species and populations of this insect group.