The influence of blood meals on accumulation of arachidonic acid by adult stable flies

Abstract

We investigated the influence of blood meals on accumulation of the polyunsaturated fatty acid (PUFA), 20:4n-6, by adult stable flies, Stomoxys calcitrans (L.). The fatty acid compositions of phospholipids (PLs) and triacylglycerols (TGs) prepared from adult male and female stable flies that had been maintained either with or without blood meals were determined, and incorporation of exogenous radioactive fatty acids into tissue lipids of adults was monitored. The major PL components were 16:0, 16:1, 18:1 and 18:2n-6. Two C 20 PUFAs, 20:4n-6 and 20:5n-3 were associated with PLs in the 1–5% range. The major TG components were 14:0 and 16:1. Although absence of the normal adult blood meals influenced the overall fatty acid profiles of male and female stable flies, proportions of C 20 PUFAs in PLs of blood-fed flies were not substantially higher than proportions of C 20 PUFAs in their sucrose-fed counterparts. The fatty acid incorporation studies indicate that the ability to incorporate exogenous fatty acids is decreased in older adult stable flies. We conclude that the larval stages of stable flies are more important for accumulation of C 20 PUFAs than the adult stages.