Essential for life, fatty acids are crucial in energy metabolism, cell and membrane structure, and physiological regulation to all organisms, including Drosophila [Stanley-Samuelson, et al. 1988]. The fatty acid compositions of all insect orders are fairly similar, in a qualitative way. Biochemical profiles include about eight components with chain lengths of 12 to 18 carbons, most of these saturated and monounsaturated fatty acids (MUFAs) plus two polyunsaturated fatty acids (PUFAs) - Linoleic acid (LA, l8:2n-6) and а-linolenic acid (ALA,18:3n-3 ) [Stanley-Samuelson, et al. 1988]. The lipids of aquatic insects and some Antarctic beetles are abundant in long chain PUFAs with a chain length of 20 or 22 carbons. Certain C20 and C22 PUFAs play important regulatory roles in reproductive biology of some insect species. For example, arachidonic acid (AA, 20:4n-6) or certain structurally related C20 and C22 PUFAs are essential nutrients for several mosquito species [Stanley-Samuelson, et al. 1988], which may be reflective of the mosquito diet compared to that of fruit flies.
D.W. Stanley-Samuelson, R. A. Jurenka, C. Cripps. Fatty acids in insects: Composition, metabolism,and biological significance. Archives of Insect Biochemistry and Physiology. 9 (1988): l -33.