External lipids of adults of the giant whitefly, Aleurodicus dugesii.
The external lipids of male and female adults of the giant whitefly, Aleurodicus dugesii, were found in three forms; as cuticular lipids, as waxy particles, and only on females, as waxy filaments. Collectively, the external lipids consisted of long-chain aldehydes, long-chain alcohols and wax esters. Cuticular lipids consisted mainly of wax esters. The major wax esters were C44 (tetracosanyl icosanoate and docosanyl docosanoate) and C46 (mainly triacontanyl hexadecanoate and tetracosanyl docosanoate). Hydrocarbons, largely n-alkanes, were minor components of the cuticular surface lipids. Both sexes produced waxy particles soon after eclosion by breaking off extruding strands (or ribbons) from anterior wax plates on their abdomens; three pairs on males and two pairs on females. These particles coated the adults and their surroundings. The waxy particles produced by the anterior wax plates of adults were a mixture of aldehydes and alcohols, predominantly C30. The wax esters were not part of the waxy particles despite being the major lipid class on the cuticular surface. In addition, the adult female has two pairs of posterior abdominal wax plates which produce waxy filaments that are broken off during oviposition and form spiral trails on the leaf. These trails appear to function to camouflage the eggs which are laid horizontally in the waxy trail. The lipid obtained from the waxy filaments from the posterior abdominal wax plates of the female was largely wax esters. The predominant wax ester was C46 (mainly triacontanyl hexadecanoate).