Species of Culex can be found throughout the globe, except at the extreme northern latitudes. Depending on the region and species, Culex mosquitoes can carry a wide array of public health threats.
Culex mosquitoes breed in various types of stagnant water. Preferred oviposition habitats such as rainwater barrels, catch basins, storm drains, and septic tanks are rich in organic material. Eggs are laid in raft-shaped batches on the water surface.