Cuticular and internal n-alkane composition ofLucilia sericatalarvae, pupae, male and female imagines: application of HPLC-LLSD and GC/MS-SIM

Abstract

AbstractThe composition of cuticular and internal n-alkanes inLucilia sericatalarvae, pupae, and male and female imagines were studied. The cuticular and internal lipid extracts were separated by HPLC-LLSD, after which the hydrocarbon fraction was identified by GC/MS in selected ion monitoring (SIM) and total ion current (TIC) modes.The cuticular lipids of the larvae contained seven n-alkanes from C23to C31. The major n-alkane inL. sericatalarvae was C29(42.1%). The total cuticular n-alkane content in the cuticular lipids was 31.46 μg g−1of the insect body. The internal lipids ofL. sericatalarvae contained five n-alkanes ranged from C25to C31. The most abundant compound was C27(61.71 μg g−1of the insect body). Eighteen n-alkanes from C14to C31were identified in the cuticular lipids of the pupae. The most abundant n-alkanes ranged from C25to C31; those with odd-numbered carbon chains were particularly abundant, the major one being C29:0(59.5%). Traces of eight cuticular n-alkanes were present. The internal lipids ofL. sericatapupae contained five n-alkanes, ranging from C25to C31. The cuticular lipids of female imagines contained 17 n-alkanes from C12to C30. Among the cuticular n-alkanes of females, C27(47.5%) was the most abundant compound. Four n-alkanes, with only odd-numbered carbon chains, were identified in the internal lipids of females. The lipids from both sexes ofL. sericatahad similar n-alkane profiles. The cuticular lipids of adult males contained 16 n-alkanes ranging from C13to C31. C27(47.9%) was the most abundant cuticular n-alkanes in males. The same n-alkanes only with odd-numbered carbon chains and in smaller quantities of C27(0.1%) were also identified in the internal lipids of males.The highest amounts of total cuticular n-alkanes were detected in males and females ofL. sericata(330.4 and 158.93 μg g−1of the insect body, respectively). The quantities of total cuticular alcohols in larvae and pupae were smaller (31.46 μg g−1and 42.08 μg g−1, respectively). The internal n-alkane contents of larvae, pupae, and male and female imagines were significantly higher than the cuticular n-alkane contents (153.53, 99.60, 360.06 and 838.76 μg g−1of the insect body, respectively).