FIGURE 2-4 Female Anopheles gambiae during a blood meal. (Photo courtesy of Dr. Robert Gwadz, NIAID, NIH)

may deposit a total of 200 to 1,000 eggs in three or more batches. Actual egg production is dependent on blood consumption. After hatching, anopheline larvae lie along the water-air interface, where it is thought that they feed on organisms along the surface film. Adult mosquitoes develop from the pupal stage within 2 to 4 days. An adult mosquito will emerge from the egg stage in 7 to 20 days, depending on the species of mosquito and environmental conditions.

Female anopheline mosquitoes can survive at least a month under favorable conditions of high humidity and moderate temperatures. That is sufficient time for them to take a blood meal, for the parasite to develop, and for the mosquito to take another blood meal and thus transmit the parasite to a second human host.

Mosquitoes are rarely found more than a few miles from their larval development site. They are readily blown short distances by the wind and have been transported internationally as unintended stowaways on airplanes.