The composition of the cuticular lipids from nymphs and exuviae of the Silverleaf Whitefly, Bemisia argentifolii

The surface lipids of Bemisia argentifolii Bellows and Perring (Homoptera: Aleyrodidae) nymphs and exuviae were characterized. The identification and distribution of lipids were determined by capillary gas chromatography (CGC) and CGC-mass spectrometry (CGC-MS). The quantity of lipid from exuviae was 80% greater than that from nymphs. The composition for the lipid classes and the chain-length distribution of each lipid class were similar for both nymphs and exuviae: wax esters (86%), long-chain aldehydes (7%), hydrocarbons (3-4%) and long-chain alcohols (3-4%). The wax esters were composed of even-numbered-carbon compounds ranging from C-38 to C-64. Structural analyses of the wax esters by CGC-MS with single ion monitoring revealed that the carbon numbers for the major acid and alcohol moieties ranged from C-14-C-28 and C-24-C-36, respectively, and the major wax ester constituents were the C-52 ester, dotriacontanyl icosanoate (27%) and the C-54 ester, tetratriacontanyl icosanoate (14%). The major aldehyde was dotriacontanal (C-32), and the major alcohols were near equal amounts of dotriacontan-1-ol (C-32) and tetratriacontan-1-ol (C-34). The major hydrocarbons for both nymphs and exuviae were odd-carbon-numbered C-25-C-35 n-alkanes. Lipids extracted from the exuviae from laboratory-reared sweetpotato whiteflies, Bemisia tabaci (Gennadius), were essentially the same as the lipids from B. argentifolii. (C) 1999 Elsevier Science Inc. All rights reserved.