Culex pipiens: The Northern House Mosquito

Wayne J. Crans, Mosquito Research & Control, Rutgers University

Why is this Mosquito Important?

Culex pipiens is usually the most common pest mosquito in urban and suburban settings
Culex pipiens is an indicator of polluted water in the immediate vicinity
Culex pipiens is recognized as the primary vector of St. Louis encephalitis (SLE) and West Nile virus in the eastern US.

Where does this Mosquito normally lay its Eggs?

In tin cans, buckets, discarded tires and other artificial containers that hold stagnant water
In untended bird baths, clogged rain gutters and plastic wading pools that hold stagnant water
In storm drains and catch basins in urban areas
In septic seepage and other foul water sources above or below ground level

How does this Mosquito Overwinter?

The last generation of adult females mate and build fat body by feeding on carbohydrates
Mated females find refuge in culverts, basements and protected areas that stay above freezing
The body metabolism slows considerably and winter is spent in a state of torpor
Females that survive the winter blood feed in spring and lay eggs that produce the summer populations

What is this Mosquito’s Range of Blood Meal Hosts?

Culex pipiens is normally considered to be a bird feeder
Some urban strains have a predilection for mammalian hosts and feed readily on humans
Most populations probably contain individuals that accept blood from mammals as well as birds

What Role does this Mosquito play in the Transmission of St. Louis Encephalitis?

SLE is a natural infection found in a variety of wild birds
Culex pipiens can function as a vector and pass the virus from one bird to the next
If virus is introduced to an urban setting, Culex pipiens can amplify the infection in urban birds
House Sparrows, an introduced species, circulate exceptionally high levels of SLE when they become infected
Culex pipiens that bite infected birds acquire the virus and are capable of passing it on to humans