GC-MS analyses of fatty-acid precursors from Lampronia capitella female abdominal tip extracts. (A) Total ion current (TIC) chromatogram of a base methanolyzed abdominal tip lipid extract. Peaks are indicating: (1) Z9–14:Me; (2) E11–14:Me and Z11–14:Me; (3) 14:Me; (4) Z9,Z11–14:Me; (5) Z9–16:Me; (6) Z11–16:Me; (7) 16:Me; (8) Z9,Z12–18:Me; (9) Z9,Z12,Z15–18:Me; (10) Z9–18:Me; (11) 18:Me; (9') Z9,Z12,Z15–18:acid. (B) DMDS derivatives from a methanolyzed abdominal tip extract from L. capitella. The trace chromatogram is obtained by selection of the Δ11 diagnostic fragment at m/z 245. Peaks labelled as Z11–14:DMDS, E11–14:DMDS and Z11–16:DMDS correspond respectively to the dimethyldisulfide adducts of methyl (Z)-11-tetradecenoate; of methyl (E)-11-tetradecenoate and of methyl (Z)-11-hexadecenoate. (C) Mass spectra of the Z11–16:DMDS and Z11–14:DMDS adducts confirming the double bond positions. The E11–14:DMDS exhibited a mass spectrum identical to the Z11–14:DMDS.