Bug FAQHouse Mosquito Complex
Culex pipiens · Order: Diptera · Family: Culicidae
Also called: Northern House Mosquito
Culex pipiens includes two forms that look the same but differ in habits. One form lives above ground and feeds mainly on birds, while the other lives underground and often bites humans and other mammals. Both forms can breed in standing water and are common in cities, especially where wastewater is poorly managed, and they can spread disease through their bites.
Is it a pest in the house?
They are major vectors of viruses and can become abundant in cities with poor wastewater management.
Source: Wikipedia
Does it bite or sting?
Form molestus bites mammals, including humans, causing itching and swelling. Hybrids bite both birds and humans and act as bridge vectors for West Nile virus. Mosquito bites can spread pathogens, leading to diseases such as West Nile virus.
How to get rid of it
Take steps to control mosquitoes.
Source: CDC
Where it lives
Form pipiens lives above ground and feeds mainly on birds. Form molestus lives underground and often bites mammals, including humans.
Source: Wikipedia
What it eats
Form pipiens primarily feeds on birds. Form molestus frequently bites mammals, including humans.
Source: Wikipedia
Life cycle
They reproduce in flood-prone or standing water.
Source: Wikipedia
Where it comes from
It originated in Africa, Asia, and Europe and is now found in temperate regions worldwide except Antarctica.
Source: Wikipedia
Lookalikes
Culex pipiens includes two morphologically indistinguishable forms: pipiens and molestus.
Source: Wikipedia
Where it is found in the US
Recorded in 40 of 51 states and DC. Most records: Illinois, Iowa, Indiana, Idaho, Utah, Maryland, Virginia, Ohio.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Do they bite humans?
Yes, the molestus form and hybrids bite humans, causing itching and swelling.
Can they spread disease?
Yes, they can transmit viruses such as West Nile through their bites.
Same family (Culicidae)
Asian Tiger MosquitoAedes albopictusCan spread germs or disease
Yellow Fever MosquitoAedes aegyptiCan spread germs or disease
Inland Floodwater MosquitoAedes vexansCan spread germs or disease
Asian Bush MosquitoAedes japonicusCan bite
Southern House MosquitoCulex quinquefasciatusCan spread germs or disease
Elephant MosquitoToxorhynchites rutilusHarmlessSources
- Wikipedia: https://en.wikipedia.org/wiki/Culex_pipiens
- CDC: https://www.cdc.gov/mosquitoes/about/index.html
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.