Northern House Mosquito

Scientific Name	Culex pippens
Survival Strategy	Freeze-avoidance
Conservation status	Least Concern

Life Cycle

Eggs
A female northern house mosquito lays 100 to 300 eggs, head-side down, assembled as a raft that floats on the surface of stagnant water. The larvae will emerge in two days.

Larva
Each Larva suspends itself just below the surface of the water with its whiskered head facing down for feeding and a snorkel-like tube protruding from the end of the abdomen for breathing. The larvae pupate in about twelve days.

Pupa
The pupae’s hardened cuticle serves as a protective case, with the job of breathing taken over by a pair of respiratory trumpets that are attached to the thorax. Pupae do not feed, but they can move in the water by wiggling. An adult mosquito emerges in two days.

Adult
Adult northern house mosquitoes are mature enough to mate in two days. After mating, the female will store sperm until she lays her eggs. Female mosquitos require a blood meal from a warm-blooded vertebrate (bird or mammal) to nourish their eggs.

Behavior

What attracts mosquitoes?
Mosquitoes are attracted to the carbon dioxide that birds and mammals exhale, as well as their body heat. Human body odors such as lactic acid and ammonia, or floral-scented perfumes or lotions, make people more appealing to these flying insects. Mosquitos are more attracted to people who recently consumed beer, wear black or other dark-colored clothing, or are pregnant. Eating bananas will not make you more attractive to mosquitoes.

Physiology

Surviving Winter
Female pupae exposed to short daylength and low temperature (autumn weather) will enter a state of diapause as inseminated adults. Before diapause, females feed on carbohydrate-rich nectar to build the fat reserves needed for overwintering. Females that go into diapause have much more fat accumulation than a non-diapausing mosquito has. They then seek shelter in culverts, caves, or unheated basements that have some form of standing water. Sites that do not drop below freezing and have high relative humidity above 90% offer the best chance of surviving through the winter. The male does not enter diapause and does not survive the winter.

With the return of warm spring weather, the female northern house mosquitos come out of diapause and seek a blood meal to develop their eggs. She will then begin laying eggs using the sperm stored from the previous fall.

Human Health
The northern house mosquito is one of the main vectors of the West Nile virus, which is the leading cause of mosquito-borne disease in the United States. The virus can cause encephalitis (inflammation of the brain) in humans and infect birds and horses. West Nile virus is not transmitted from person to person.

Diet

The female northern house mosquito’s diet typically consists of vertebrae blood, with a preference for bird blood. Males feed on plant nectar. In early fall, inseminated females will also feed on sugary nectar to store fat for overwintering.

Lifespan and Mortality

The lifespan of most northern house mosquitoes is a few weeks, the exception being inseminated females who overwinter as adults.

Predators
Culex larvae are eaten by dragonfly larvae (nymphs), whirligig beetles, and water striders. Adult mosquitoes are food for bats, dragonflies, spiders, and many birds (most notably, purple martins).

Climate Vulnerability

Climate change will likely increase the range and winter survival of northern house mosquitoes. More mosquitoes will also expose more people to mosquito-borne pathogens.

Never stop learning

Entomology: The itchy bump of a mosquito bite is a mild immune reaction to the female mosquito’s saliva. Male mosquitoes do not bite and only feed on plant nectar.
Epidemiology: More than one million people die from mosquito-borne diseases every year.
Ecology: Mosquitoes play an essential ecological role as pollinators and as a food source for other wildlife.

References

Midwest Center of Excellence: Vector-borne Diseases http://mcevbd.wisc.edu/mosquitoes/culex-pipiens

Culex pipiens, northern house mosquito, Authors: Abdullah A. Alomar, Nathan D. Burkett-Cadena, Derrick K. Mathias, University of Florida https://entnemdept.ufl.edu/creatures/aquatic/culex_pipiens.html

Life Cycle of Culex Species Mosquitoes | Mosquitoes | CDC https://www.cdc.gov/mosquitoes/about/life-cycles/culex.html

Illnesses Spread by Mosquitoes in Wisconsin: Wisconsin Department of Health Services https://www.dhs.wisconsin.gov/mosquito/index.htm

Mosquito: The Story of Mankind’s Deadliest Foe by Andrew Spielman, Michael D’Antonio. Faber and Faber, pp 248. ISBN 0 571 20980 7.

V. Hongoh, L. Berrang-Ford, M.E. Scott, L.R. Lindsay, Expanding geographical distribution of the mosquito, Culex pipiens, in Canada under climate change, Applied Geography, Volume 33, 2012, Pages 53-62, ISSN 0143-6228, https://doi.org/10.1016/j.apgeog.2011.05.015