Northern House Mosquito

• Only the female takes blood, which she needs to develop her eggs.
• It is one of the main vectors of West Nile virus.
• Its eggs are grouped into small boat-shaped rafts that float on the water.
• It is the common house mosquito, the one that buzzes around the bedroom in summer. That buzz is the beating of its wings, and it has a purpose: males and females adjust their wingbeat frequency to synchronise during courtship.
• It is the main vector of West Nile virus in Europe and North America, a virus that circulates among birds and for which people and horses are accidental hosts.
• It has two very different ecological forms: the surface form, which bites mainly birds and needs to hibernate and to mate in swarms, and the underground form, which lives in sewers and metro systems, bites mammals, does not hibernate and can lay eggs without a blood meal.
• That underground form starred in a famous episode: the London Underground population, isolated below ground, was studied throughout the twentieth century as a case of speciation in progress, and during the bombing raids of the Second World War it tormented those sheltering in the tunnels.
• The female lays her eggs clustered in a floating raft of a couple of hundred, which stays afloat like a cork.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat & environment

Urban, suburban and rural areas across the temperate northern hemisphere, tied to standing or polluted water

Birth weight

A tiny egg under 1 mm, laid in floating rafts of 100-350

Size at birth

A fast-growing larva (a wriggler) through 4 instars in standing water

Sexual maturity

Reached once metamorphosis is complete, barely days after the egg hatches

Gestation / incubation

A full cycle from egg to adult of 1 to 2 weeks depending on temperature (under a week in summer)

Litter / clutch size

100 to 350 eggs per floating raft, and a female may produce several rafts in her life

Sources consulted: MosquitoMagnet; CDC Culex Life Cycle; Indiana Dept. of Health; Britannica; bioRxiv (biocontrol predation study); Ohioline Ohio State University; ScienceInsights; Restored CDC