Hydrocarbons of Rhodnius prolixus, a Chagas disease vector

The surface hydrocarbons of the blood-sucking insect, Rhodnius prolixus, a major Chagas disease vector in Venezuela, Colombia and Central America, wer e characterized by capillary gas chromatography coupled to mass spectrometr y (CGC-MS). A total of 54 single or multicomponent peaks of saturated, stra ight-chain and methyl-branched hydrocarbons were identified. Major n-alkane s were n-C27, n-C29, n-C31 and n-C33 hydrocarbons. In the branched fraction , methyl groups were at positions 3, 5, 7, 11, 13, 15 and 17- for monomethy l isomers, and separated by three or five methylene groups for the trimethy l or tetramethyl derivatives. For the higher molecular weight components of 37, 39 and 41 atoms in the carbon skeleton, the di-, tri- and tetramethyl branches were usually separated by three or five, and sometimes 7, 11 or 13 , methylene groups. The internal hydrocarbon pool contained larger amounts of the higher molecular weight methyl-branched components. Qualitative diff erences among epicuticular and internal hydrocarbon compositions were detec ted, both in adult and nymphal stages. No significant sexual dimorphism was detected, but a significant shift in the major n-alkane components was evi dent from the nymphal to the adult stage, differing also in the relative am ounts of the higher molecular weight methyl-branched chains. Comparison of the hydrocarbon components to that of other Chagas disease vectors is discu ssed. (C) 2001 Elsevier Science Inc. All rights reserved.