is the most widely distributed mosquito in the world. It is found on every
continent except Antarctica and it carries a number of diseases, especially
arboviruses (arthropod-borne virus). Culex tarsalis is a vector
for Western Equine encephalitis.
Eggs of these mosquitoes,
typically for culicines, are laid singly or in rafts and although they
may stick to the surface, they may sink if the water is disturbed. Culex
prefers water contaminated with organic matter for the development of
the larvae and in will grow well in septic tanks.
Disease is spread
by females. Males do not bite. The females take blood meals that are used
to support the development of eggs. Culex is described as zoophagic
because it takes its meals from animals as well as humans and can also
be described as ornithophagic because it frequently feeds on birds. Any
disease that is carried by Culex can therefore become difficult
to eradicate because any animal community that it feeds on can become
a reservoir and mobile species, such as birds, can spread the disease
through a large area. This was seen in 1999 in the Eastern United States
when West Nile virus was introduced into the area. Culex pipiens
feeds at night.
Feeding is described
as endophagic because the mosquito prefers to feed in and around structures
and the mosquito then rests in cool damp spots within structures while
the meal is digested (endophilic behavior). A blood meal takes 2-7 days
to digest and 1-3 meals are needed to complete development of clutch of
eggs. Transmission comes from repeated biting when the mosquito injects
saliva that acts as an anticoagulant.