Aedes aegypti — the yellow fever mosquito
Aedes aegypti
Quick answer
Aedes aegypti is a small, dark, white-marked mosquito that bites during the day, not at dusk — with peaks after sunrise and before sunset. It breeds in tiny artificial containers around homes, prefers to bite humans, and is the primary vector of dengue, Zika, chikungunya, and yellow fever. It responds strongly to CO₂ and heat, so a CO₂ + heat trap targets it well — though personal protection during the day still matters because it is a daytime feeder.
Biology & identification
A small (~4–7 mm) dark mosquito with white lyre-shaped markings on the thorax and banded legs. It is the archetypal container-breeder and human-specialist (anthropophilic): a female lays eggs singly on the inner walls of small artificial containers just above the waterline.
Those eggs are desiccation-resistant, surviving dry for weeks to months and hatching when reflooded — which is how the species hitchhikes and reestablishes. Larvae mature to biting adults in roughly 7–10 days in warm weather. Adults stay close to where they emerged (flight range often only tens to a few hundred meters) and rest indoors and in shaded vegetation.
It thrives in urban and suburban settings and is highly sub-tropical to tropical, with U.S. presence concentrated in the Gulf states, the Southeast, the desert Southwest, and parts of California.
Peak activity — when it bites
Diurnal and bimodal — host-seeking peaks in the hours after sunrise and again in the late afternoon and before sunset, with biting continuing through the day in shade.
This is the species that breaks the "mosquitoes only bite at dusk" myth. It is not primarily a night biter.
Why it bites — host-seeking
Only the female bites, needing a blood-protein meal to develop eggs. She is strongly attracted to CO₂, human skin odors (lactic acid, ammonia), heat, and dark colors.
Aedes aegypti is unusually human-preferring — it will choose people over other animals and often takes multiple small blood meals from several people in one cycle, which raises its efficiency as a disease vector.
How the CO₂ trap targets it
A good trap target. Aedes aegypti is highly responsive to CO₂ and heat, so a CO₂ + heat trap draws host-seeking females effectively (USDA-ARS attractant work).
Honest caveat: because it is a daytime biter that breeds right at the house in tiny containers, trapping should be paired with rigorous source reduction (tip-and-toss weekly) and daytime personal repellent. The trap suppresses the flying adult population but will not substitute for emptying the bottle cap it bred in.
Range & vector status
Primary vector of dengue, Zika, chikungunya, and yellow fever worldwide; the most medically important container Aedes. Present across the warmer U.S. South and Southwest.
This is factual vector status: the trap reduces biting pressure, it does not prevent disease.
Sources
- U.S. CDC, "Aedes aegypti and Aedes albopictus mosquitoes — where mosquitoes live."link pending verification
- WHO, "Dengue and severe dengue" fact sheet (vector status).
- Kline, D.L. et al., CO₂ attractant response in Aedes.link pending verification
Common questions
Does Aedes aegypti bite during the day?
Yes. It is a daytime (diurnal) biter with peaks after sunrise and before sunset, and it keeps biting in shade through the day. It is not a dusk-only mosquito.
Where does Aedes aegypti breed?
In tiny artificial containers around the home — bottle caps, saucers, buckets, tire ruts — laying eggs on the inner walls just above the waterline. Weekly tip-and-toss of standing water is the most effective source control.
Does a CO₂ trap catch Aedes aegypti?
Yes — it is highly responsive to CO₂ and heat, so a CO₂ + heat trap targets it well. Because it is a daytime container-breeder, pair the trap with weekly source reduction and daytime repellent.