THE SURFACE WAX COMPOSITION OF THE EXUVIAE AND ADULTS OF ALEYRODES SINGULARIS

Long-chain aldehydes, alcohols, hydrocarbons and wax esters were major components of the external lipids of adult Aleyrodes singularis. In e xuviae, acetate esters replaced the hydrocarbons as a major component. The major long-chain alcohol and aldehyde from adults were C32 and we re essentially the exclusive components of the wax particles. The majo r alcohol from exuviae was C26 and the aldehydes were C26, C28, C30 an d C32. The major acetate esters were C28 and C30 in both adults and ex uviae. There were wax esters of similar carbon number in adults and ex uviae although the exuviae had a greater amount of wax esters with uns aturated fatty acids. The fatty acid and alcohol composition of the wa x esters differed markedly between adults and exuviae. Wax esters of a dults had similar amounts of C16, C18, C20, C22 and C24 fatty acids wh ile those from exuviae contained largely C16 and C18. The major alcoho l in the wax esters of adults was C22 and those of exuviae were C26 an d C28. The distribution of fatty acids and alcohols among wax esters o f varying chain length also differed between adults and exuviae: in ad ults C22 was the major fatty acid found in the dominant wax ester, C44 and the C22 alcohol was the major alcohol and found in wax esters C42 and C44. In exuviae C16 and C18 were the major fatty acids found in m ost wax esters and a C28 alcohol was the major alcohol found in wax ea ters C44 and C46, the two dominant wax esters in exuviae. It was clear that the difference in chemistry of the wax esters between the adults and exuviae is not evident unless the acid and alcohol moieties are c haracterized. (C) 1998 Elsevier Science Inc. All rights reserved.