How mosquitoes actually work

The short answer

Almost everything people want to know about mosquitoes, how to avoid their bites and how to keep them out of a yard, follows from a few basic facts about their biology. Mosquitoes need standing water to breed. Only females bite, and they do it to make eggs, not to feed themselves. They find you mostly by smell and heat, not by sight. And as adults they do not live long or travel especially far.

Once those points click into place, the rest tends to make sense. Dumping a bucket of water is not a chore, it is breaking the life cycle. A fan on the patio is not a gimmick, it scatters the carbon dioxide plume they follow. This page walks through the biology in brief, and links to deeper pages on each topic.

The life cycle in brief

Mosquitoes pass through four stages: egg, larva, pupa, and adult. The first three all happen in water, which is the single most important fact for anyone trying to control them (Source 1, Source 2).

Eggs are laid on or near water, or in spots that later flood, and they hatch when covered by water (Source 2, Source 3). The larvae, sometimes called wrigglers, live entirely in the water and feed on bacteria and other tiny organisms, molting several times as they grow (Source 1, Source 3). Next comes the pupa, also aquatic, which does not feed and simply develops until the adult emerges (Source 1). Only the adult is a flying, air-breathing insect.

The whole sequence is quick. It commonly takes about two weeks, but depending on temperature and conditions it can run from as little as 4 days to as long as a month (Source 2, Source 3). Because every step before adulthood depends on standing water, removing or emptying water is the most direct way to stop mosquitoes before they ever fly. See the life cycle page for the full stage-by-stage detail.

Only females bite, and why

Only female mosquitoes bite. They take blood so that their eggs can mature before being laid, and it serves no feeding or energy function for the mosquito herself (Source 4). Males do not bite at all, and in fact lack the mouthparts to pierce skin (Source 4, Source 5).

For their own nourishment, both males and females feed on plant nectar and other plant sugars (Source 4). So a biting mosquito is always a female that is provisioning a batch of eggs. That is why bite avoidance and breeding-site removal are really the same fight from two directions. More on this on the why females bite page.

How they find you

Mosquitoes hunt in layers, using different cues at different distances (Source 6).

From far off, on the order of tens of meters, a female picks up the plume of carbon dioxide that a person or animal breathes out. That plume raises her interest and makes her more likely to steer toward nearby visual targets (Source 6). At closer range she uses vision, and within about a meter she homes in on body heat, showing a preference for warm surfaces near human body temperature (Source 6).

These systems work largely independently, which is part of why host-seeking is so hard to shut off. Knock out one cue and the others still operate (Source 6). It also explains practical tactics: moving air disrupts the carbon dioxide trail, and covering skin reduces both the scent and the heat she is tracking. The how they find you page goes deeper on each sense.

How they live

Adult mosquitoes are short-lived. Most adult females live about 2 to 3 weeks, though species that overwinter in sheltered spots such as garages, culverts, and attics can survive as long as 6 months (Source 4). Some species get through cold months by hibernating in protected places (Source 3).

Most mosquitoes also stay close to where they hatched. House-oriented species like the Asian tiger mosquito have flight ranges of only about 300 feet, and most species range roughly 1 to 3 miles. Saltmarsh mosquitoes are the exception, sometimes traveling 20 to 40 miles, and much farther in rare cases (Source 4). The practical takeaway is that most of the mosquitoes biting you were likely born nearby, which is why local water sources matter so much. See the how they live page for resting sites and flight in more detail.

Their place in nature

It is fair to ask what mosquitoes are good for. In ecological terms, they are food and, to a lesser degree, pollinators.

Both males and females visit flowers for nectar, and in doing so they move pollen between plants; some plants, including certain orchids, rely heavily on mosquitoes for pollination (Source 7). Their larvae are an aquatic food source for fish, dragonfly larvae, and other small animals, while the flying adults are eaten by birds, bats, dragonflies, and more (Source 7, Source 8). So even a household pest sits inside a food web that many other animals draw on. The their place in nature page covers this in more depth.

Sources

1. Centers for Disease Control and Prevention, “Life Cycle of Anopheles Mosquitoes.” Four stages (egg, larva, pupa, adult); larvae and pupae are aquatic; larvae feed on bacteria and microorganisms; adults are short-lived flying insects. https://www.cdc.gov/mosquitoes/about/life-cycle-of-anopheles-mosquitoes.html (accessed 2026-07-20; page returned 403 to automated fetch, facts drawn from the search-result summary of this official CDC page).
2. U.S. Environmental Protection Agency, “Mosquito Life Cycle.” First three stages occur in water; eggs hatch when exposed to water; full cycle typically about two weeks, ranging from 4 days to a month. https://www.epa.gov/mosquitocontrol/mosquito-life-cycle (accessed 2026-07-20).
3. Penn State Extension, “The Life Cycle of a Mosquito.” Water needed throughout; larvae to pupae in as few as 5 days, pupae to adults in 2 to 3 days; only females bite, needing blood to develop eggs; adults live a few weeks; some species overwinter by hibernating. https://extension.psu.edu/the-life-cycle-of-a-mosquito (accessed 2026-07-20).
4. American Mosquito Control Association, “FAQs.” Most adult females live 2 to 3 weeks, overwintering species up to 6 months; flight ranges (about 300 feet for house-breeders, 1 to 3 miles for most species, 20 to 40 miles and beyond for saltmarsh species); females take blood only to mature eggs, males do not bite, both sexes feed on plant nectar. https://www.mosquito.org/faqs/ (accessed 2026-07-20).
5. Penn State Extension, “The Life Cycle of a Mosquito.” Confirms only females bite. https://extension.psu.edu/the-life-cycle-of-a-mosquito (accessed 2026-07-20).
6. California Institute of Technology, “Mosquitoes Use Smell to See Their Hosts.” Layered host-seeking: carbon dioxide detected at roughly 10 to 50 meters raises interest and steers toward visual targets; vision at medium range; body heat within about a meter, with preference for surfaces near human body temperature; cues operate independently. https://www.caltech.edu/about/news/mosquitoes-use-smell-see-their-hosts-47338 (accessed 2026-07-20).
7. Encyclopaedia Britannica, “What Purposes Do Mosquitoes Serve in Ecosystems?” Nectar-feeding mosquitoes act as pollinators for many plants; larvae are prey for aquatic animals; adults are prey for birds and bats. https://www.britannica.com/story/what-purposes-do-mosquitoes-serve-in-ecosystems (accessed 2026-07-20; page returned 403 to automated fetch, facts drawn from the search-result summary of this page).
8. National Wildlife Federation, “What Purpose Do Mosquitoes Serve?” Mosquitoes are prey in both aquatic larval and winged adult form for wildlife including dragonflies, fish, bats, and birds; nectar is their primary food and adults move pollen between plants. https://blog.nwf.org/2020/09/what-purpose-do-mosquitoes-serve/ (accessed 2026-07-20).

Explore mosquito biology

• The mosquito life cycle, stage by stage
• Why only female mosquitoes bite
• How mosquitoes find you
• How mosquitoes live: lifespan, resting, and flight
• Mosquitoes’ place in nature

Educational note: This page is a general science reference and is not medical, pest-control, or public-health advice. For guidance on disease risk or an infestation, consult your local health department or mosquito control district.

Last reviewed 20 July 2026.