Formation of lipid reserves in fat body and eggs of the yellow fever mosquito, Aedes aegypti

We examined the accumulation of lipids in adult females of the mosquito, Ae des aegypti. Females emerged with about 100 mug lipid in the fat body. With access to sugar water lipids increased over seven days to 300 mug. After a blood meal on day five, sugar-fed females accumulated 120-140 mug of lipid s in their ovaries within 2 days. At the same time the lipid content of the fat body decreased by 100 mug, indicating transfer of lipids from fat body to oocytes. Experiments in which fat body lipids were prelabelled support this conclusion. Label was transferred to oocytes: in mature oocytes the sp ecific radioactivity of lipids was 80% of the specific radioactivity of pre labeled fat body lipids. Components of blood meals are also used to synthes ize oocyte Lipids. Fat bodies of females starved for four days had only 27 mug of lipids left. When these females were given a blood meal, they mature d oocytes, although the number of ooyctes was reduced and ovaries contained only half the amount of lipids found in ovaries of females which had first fed on sugar water. Fat body Lipids of these females had only slightly inc reased to 36 mug. This demonstrates that female Ae. aegypti use sugar to sy nthesize lipids, but they can also use components of blood for this purpose . (C) 2001 Elsevier Science Ltd, All rights reserved.