Cuticular lipids of larvae of Attagenus megatoma

Abstract

The cuticular lipids extracted from the larvae of the black carpet beetle, Attagenus megatoma, form a very hard wax with a melting point of 76–78°C. The hydrocarbons amounted to 10–12% of the wax and were primarily odd-chain n- alkanes from C 25C 35 although even-chain hydrocarbons were also present. There were no unsaturated hydrocarbons, and branched-chain alkanes amounted to <2% of the hydrocarbon fraction. Wax esters, consisting mainly of saturated C 20, C 22 and C 24 fatty acids esterified to primary alcohols with chain lengths of C 18-C 32, were the major components (about 65%) of the lipid fraction. Free fatty acids amounted to 11–13% of the cuticular wax and the fraction contained a higher percentage of unsaturated fatty acids than did the bound fatty acids. When the larvae were treated with the food additive tricalcium phosphate (TCP), tested as a surface active dust, the free fatty acid fraction, particularly the unsaturated acids, was significantly reduced. The TCP treatment did not affect the ratios of the cuticular hydrocarbons or the weights of any of the other lipid fractions.