The Culex is a very diverse genus of mosquito, and is also known as the common house mosquito. It can be found all over the world from the tropics to cool temperate regions, although it is not found in the extreme northern latitudes. It is the most common genus of mosquito found in some of the main cities in the US.
They vary in size depending on the genus with most adult Culex measuring between 4mm and 10mm. They have short palps in comparison to the Anopheles genus, and tend to keep their bodies parallel to a surface with the head bent down. They are mainly brown in colour but can have transverse white lines on the upper surface of their abdomen. They also have a blunt tip on the abdomen, and the wings are clear and transparent.
They are typically weak fliers and only live up to 2 weeks. Much like the Anopheles mosquitoes, the males feed solely on plant nectar, while the females need blood meals for the development of eggs. They typically get their blood meals from birds not humans, and is not considered as much of a threat to human life as the Anopheles and Aedes mosquitoes. The eggs are laid on surface of standing water where there is no plant life such as puddles, buckets and old tyres.
They are painful and persistent biters who prefer to attack at dusk and after dark, and they readily enter houses for blood meals.
Culex are the primary vectors of West Nile virus, and transmit other important diseases such as filariasis, Japanese encephalitis, St. Louis encephalitis, Murray Valley encephalitis, Red River viruses and Rift Valley fever.