*3.4. Structure Elucidations of Alkenes*

From a concentrated dichloromethane extract of a female *A. fargeii,* the two fractions containing C15-alkenes and C17-alkenes were isolated by semi-preparative GC. Each fraction, in hexane (30 μL), was treated with DMDS (50 μL) and iodine in diethyl ether (5 μL, 60 mg/mL). The reaction mixtures were left at 40 ◦C in vials over night before being washed with sodium bisulphite (5%) and concentrated to ca. 20 μL under nitrogen before being analysed by GC-MS [41]. The fraction containing C15-alkenes contained two compounds, with characteristic ions for 6-pentadecene (M = 304, fragments *m*/*z* = 131, 173) and 7-pentadecene (M = 304, fragments *m*/*z* = 145, 159). The fraction containing C17-alkenes contained one monoene and one diene, with characteristic ions for 8-heptadecene (M = 332, fragments *m*/*z* = 159, 173, also present in *O. insectifera*) and 6,9-heptadecene (M = 362, fragments *m*/*z* = 131, **155**, 159, **183**, 203 and 231) [42].
