Effects of sodium chloride concentrations on larvae and pupae of Aedes aegypti

Abstract

Aedes aegypti is one of the commonest mosquitoes in the tropics and sub topics, feeding on human blood when exposed and is responsible for the transmission of urban yellow fever in Africa and out side Africa, it transmits dengue fever. Aedes aegypti are basically freshwater mosquito. The effect of different concentrations of saline solution on the survivorship of larvae and pupae of Aedes aegypti is studied to possibly find a control measure that will utilize waste water from our kitchen which contains some form of saline solution. Different grams of NaCl were measured and dissolved in 100 ml of water to get the different concentrations and the different larva were subsequently introduced into these solutions. Increase in salinity, brings about increase in mortality rate as well as increase in length of days for development. While there was no mortality in saline concentration between 0.1 - 1.0 % the length of days for development remains almost the same as in freshwater. But from 1.5%-5.0% saline concentration, mortality recorded was on the increase and rate of development was delayed taking about 4.5 days in pupa as against the normal 2.5 days on the average. However optimal mortality was recorded in the first larval instars having 100% mortality in 1.5% to 5.0%. Where as the pupal stage recorded the highest survivorship rate of 83.3% in all. Finally it was observed that Aedes aegypti even though a freshwater mosquito tolerated some level of salinity and at the same time can be controlled effectively with NaCl solution.