Figure 3.

Life cycle of Anopheles mosquitoes and olfactory-guided behaviors of adults. Left: Anopheles mosquitoes go through 4 main developmental stages. Eggs (bottom) are laid individually in water and remain on the surface due to egg floats. After approximately 24 h, they hatch into larvae (left), which will feed on bacteria and detritus in the water as they grow and molt through 4 instars. This process takes about 1 week, depending on environmental conditions. With the final molt, larvae become pupae (top), which no longer feed but are still motile. Adults (right) emerge from pupae approximately 24 h later. Male mosquitoes are indicated in blue, female mosquitoes in light red. Right: Both male and female mosquitoes must forage for nectar from plants (top). Mosquitoes mate in swarms of males (second from top), into which females fly. Only females engage in host-seeking and blood feeding behaviors (second from bottom), as well as oviposition or egg-laying (bottom). Bracket: many factors affect the attractiveness of a human host to a female Anopheles mosquito, including genetic influences on skin flora and emitted odor volatiles, physiological state such as age and pregnancy, diet, the use of personal hygiene products and mosquito repellents, and immune response, including infection with the Plasmodium parasite (bottom).