New natural aliphatic ethers in cuticular waxes of gregarious and solitary locustsLocusta migratoria cinerascens (II).

An original homologous series of di-n-alkyl ethers has been revealed in the cuticular waxes ofLocusta migratoria cinerascens. The mass spectrometry-electron impact, and positive and negative chemical ionization of these derivatives has been investigated in order to define the optimal conditions for structural determination. The quantitative analyses have shown that the ethers C n1H2n1 + 1-O-C n2H2n2+1 with an odd number of carbon atoms (n1 even andn2 odd) are clearly predominant. Furthermore, they have made a double phasal dimorphism appear: heavier ethers in the case of the solitary insects and majority participation ofn-alkyl chains in C16 (60%) in the case of the gregarious locusts and in C18 (50%) in the solitary ones.