Blood meal as a regulator of triacylglycerol synthesis in the haematophagous stable fly,Stomoxys calcitrans

Accumulation of triacylglycerol and glycogen reserves following meals of blood and/or sugar-water was investigated in the haematophagous stable fly,Stomoxys calcitrans. In the starved fly, triacylglycerol reserves appear to be utilized predominantly for energy requirements. When the starved flies were fed one meal of 1.0 M sucrose-water, they accumulated considerable amounts of glycogen but there was no increase in the triacylglycerol content. Starved flies fed one meal of blood accumulated large quantities of triacylglycerol but no glycogen; in those flies fed sugar-water and blood, glycogen and triacylglycerol accumulated. This study shows that the stable fly preferentially utilizes blood for triacylglycerol synthesis and sugar for glycogen synthesis. It is suggested that one or more factor(s) in the blood meal influences accumulation of triacylglycerol in this insect, possibly through an hormone from the corpora cardiaca-corpora allata complex.