Effects of sodium concentration on Aedes triseriatus (Diptera: Culicidae) and microorganisms in treeholes

A 2-factor field microcosm experiment with 2 concentrations of sodium ([Na]) was performed with and without mosquitoes to test the hypothesis that Na is a limiting nutrient for the treehole mosquito, Aedes triseriatus (Say), at concentrations observed in the field. This experiment also tested the effects of both water [Na] and mosquito larvae on cohabiting treehole microorganisms. Female Ae. triseriatus emerging from microcosms with high-[Na] were significantly larger than females emerging from low-[Na] microcosms. There was no effect of [Na] on the size of males; however, males had higher body [Na] than females at both [Na]. Densities of protozoans were lower in the presence of mosquitoes, and densities of bacteria were lower at high than low [Na]. Water [Na] may affect mosquito populations by decreasing energy expenditures to obtain Na at higher [Na], allowing for more allocation to growth. Males were not affected by the [Na]s tested here. This experiment agrees with field observations and other laboratory studies indicating that [Na] may affect populations of Ae. triseriatus under certain conditions.