Cuticular lipids of greenhouse whitefly and sweetpotato whitefly type A and B (Homoptera: Aleyrodidae) pupal exuviae on the same hosts

Cuticular lipids were extracted and chemically characterized from the pupal exuviae and associated dorsal extrusions and palisade wall of the exuviae that are secondary structures of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood), and from pupal exuviae of the sweetpotato whitefly, Bemisia tabaci (Gennadius), type B reared on tomato, poinsettia, broccoli, tobacco, or lettuce. The pupal exuviae of T. vaporariorum separates completely at adult eclosion from its palisade wall (not present in B. tabaci), allowing removal of the exuviae for analysis of its cuticular lipids. Four classes of lipids were detected from all hosts in the exuviae of T. vaporariorum: paraffins, alcohols, aldehydes, and acetates, whereas variable combinations of paraffins, alcohols, and aldehydes were detected in B. tabaci, T. vaporariorum exuviae on all hosts had significantly more total lipids than did B. tabaci. Both lipids class and constituent abundance were influenced significantly by different interactions of the whitefly and host plant. In the greenhouse whitefly, the four lipid classes were insect controlled and variability within class was influenced by the host plant, whereas in the sweetpotato whitefly type B, lipid class variability was random and directly related to host. Alcohols were the most abundant lipid found in T. vaporariorum, whereas no particular lipid class was consistently predominant in B. tabaci.