Fatty acid compositions of phospholipids and triacylglycerols of selected tissues, and fatty acid biosynthesis in adult periodical cicadas, Magicicada septendecim

Abstract

Fatty acid compositions of phospholipids and triacylglycerols prepared from selected body segments (head/thorax and abdomen) and tissues (fat body, alimentary canal, gonads, head and thoracic muscles) of adults of the periodical cicada, Magicicada septendecim, were determined. Adult males and females yielded similar fatty acid profiles. Saturated and unsaturated C16 and C18 fatty acids were the predominant components, which varied slightly among tissues. The eicosanoid-precursor polyunsaturated fatty acid, 20:4 n-6, was present in very low quantities, which varied among tissue sources. Adult periodical cicadas were competent to biosynthesize fatty acids from radioactive acetate. Compared to males, females incorporated just over five times more radioactivity into fatty acids. The radioactive components were incorporated into complex lipids in the fat body and gonads. In the fat body and ovaries, most radioactivity was incorporated into neutral lipid fractions, while in testes most radioactivity was incorporated into phospholipids. These data indicate that even though periodical cicadas have evolved very unusual life history patterns, fatty acid metabolism and composition in adults is similar to patterns seen in many terrestrial insect species.