Temperature independence of the composition of triglyceride fatty acids synthesized de novo by the mosquito.

The hypothesis that depot fat is more unsaturated when it is synthesized at lower temperatures was tested in the mosquito. Female mosquitoes (Aedes sollicitans) were starved until no triglycerides remained. A single dose of sugar was fed and the mosquitoes were maintained at different temperatures. Approximately the same amount of triglyceride was synthesized per mosquito at each temperature, although at different rates. Mosquitoes maintained at low temperatures did not synthesize more unsaturated triglycerides than those at higher temperatures: the fatty acid composition was essentially the same from 10 to 35 degrees. The triglycerides synthesized from sugar contained no poly-unsaturated fatty acids. Total amounts and composition of phospholipid fatty acids remained unaltered during sugar feeding. When deprived of food, the mosquitoes catabolized triglyceride fatty acids randomly; cold-exposure did not cause selective retention or utilization of any individual fatty acid.