Cuticular lipids of the booklouse, Liposcelis bostrychophila: hydrocarbons, aldehydes, fatty acids, and fatty acid amides

Abstract

The booklouse, Liposcelis bostrychophila, is an increasingly common pest of stored food products worldwide. We report here the cuticular lipid composition of this pest (the first report of the hydrocarbons of any member of the Order Psocoptera and the first report of fatty acid amides as cuticular components for any insect). No unsaturated hydrocarbons were present. A homologous series of n-alkanes (C21-C34), monomethyl alkanes (3-, 4-, 5-, 7-, 9-, 11-, 12-, 13- and 15-methyl-) with a carbon chain range of C28-C42, and dimethyl alkanes (3, 7-; 9, 13-; 11, 15-; 13, 17-; 9, 21-; 11, 19-; and 13, 21-) with a carbon number range of C31-C41 were identified. The relative abundances of these hydrocarbons were low, comprising approximately 0.0125% of total biomass. The amides were a homologous series (C16-C22 in chain length), with the major amide being stearoyl amide. In addition to the amides, free fatty acids (C16:1, C16:0, C18:2, C18:1, and C18:0 in chain length) and three straight chain aldehydes (C15, C16, and C17:1 in chain length) also occurred as cuticular components. These findings are discussed in terms of the chemical and physiological ecology of this species.