Influence of Rainfall on Culex nigripalpus (Diptera: Culicidae) Blood-Feeding Behavior in Indian River County, Florida

Abstract

Culex nigripalpus Theobald abundance was monitored by ground aspirator collections taken three times a week at a site in Indian River County, Fla. from January 1985 through December 1987. Aspirator collections allowed daily surveillance of fluctuations in mosquito abundance and changes in blood-feeding behavior. A Time Series Analysis of the 3-yr period revealed a significant cross correlation between C. nigripalpus engorgement and daily rainfall. This was especially pronounced in 1985, when St. Louis encephalitis virus was common in Indian River County, but was much less pronounced in 1987, when no virus activity was recorded. Rainfall in July, August, and September strongly influenced mosquito abundance during the autumn and early winter when virus transmission was most common. Dry conditions during July and August 1987 reduced mosquito abundance drastically during the following autumn.