INHIBITION OF BLOOD DIGESTION AND OOCYTE GROWTH IN AEDES AEGYPTI BY 5-FLUOROURACIL

Abstract

Oviposition in Aedes aegypti mosquitoes is inhibited by 5-fluorouracil (FU); 0.01% FU fed in the blood meal or 0.05% FU fed in sugar solution before the blood meal cause over 95% inhibition of oviposi-tion. This effect is temporary: some of the FU-treated females which laid no eggs after their 1st blood meal recover their ability to oviposit after a 2nd blood meal. The eggs laid by FU-treated females hatch normally. FU-treatment inhibits midgut protease production, retards blood digestion, and slows down the growth of oocytes. The extent of protease inhibition and the rate of oocyte growth is proportional to the amount of FU and the time interval between FU-treatment and the blood meal. The effect of FU on oocyte maturation in mosquitoes could be an indirect effect (oocyte growth is inhibited because of a lack of midgut protease) or a direct effect of FU on the synthesis of specific proteins in all parts of the insect body.