Reproduced from Wing Beats of the AMCA, the official publication of the Florida Mosquito Control Association. Please use the following citation when referring to this article:
Womack, M. 1993. The yellow fever mosquito, Aedes aegypti. Wing Beats, Vol. 5(4):4.
The Yellow Fever Mosquito, Aedes aegypti
DR. MICHAEL WOMACK
Importance
Aedes aegypti is historically the primary vector for the viruses that cause human dengue and yellow fever. Subtropical and tropical zones of the Americas are still endemic for these diseases. In Asia, this species is also considered the principal vector of chikungunya virus. Past concerted efforts to eradicate this vector within the United States failed.
Geographic Distribution
Worldwide, this species has a cosmopolitan range extending from 40 degrees N to 40 degrees S latitude. The species is found throughout most tropical to subtropical world regions. Survival is poor in hot, dry climates. In the eastern United States, Ae. aegypti occurs in Mississippi, Alabama, Georgia, Florida, Tennessee, Kentucky, South Carolina, North Carolina, Virginia, New York, Delaware, Maryland and the District of Columbia. Western states i n c I u d e Arkansas, Illinois, Kansas, Louisiana, Missouri, Oklahoma, New Mexico and Texas. Densities are greatest in the Gulf Coastal states.
Adult Description
Ae. aegypti is a medium-sized blackish mosquito easily recognized by a silvery-white 'lyre-shaped" pattern of scales on its scutum. Segments 1 to 4 of the hind tarsi possess broad basal white rings, segment 5 is white. The coloration of both sexes is similar.
Larval Habitat
The eggs are deposited on damp surfaces within artificial containers such as cans, jars, urns or rain-water containers. Old automobile tires provide an excellent larval habitat and an adult resting site. In tropical climates, larvae are also encountered in natural water retaining cavities in tree holes and herbaceous plants. The eggs of Ae. aegypti can resist desiccation for up to 1 year. Eggs hatch when flooded by water that is deoxygenated.
Associated Species
Larval habitats are often shared with other container-breeding mosquitoes in the southeast such as Aedes albopictus, Aedes triseriatus, Aedes atropalpus, Orthopodomyia signifera, Toxorhynchites rutilis, Culex nigripalpus, Culex (pipiens) quinquefasciatus, Culex restuans, and Culex salinarius.
Larval Behavior
Larvae feed on the aquatic microbiota that develops in artificial contaiiaers. The total time for development through all 4 instars is dependent upon water temperature and food supply, and typically ranges from 4 to 10 days. Larvae die at temperatures below 10 degrees and above 44 degrees Celsius.
Bloodfeeding
The yellow fever mosquito is a peridomestic species found not far from human dwellings. This species is particularly abundant in towns and cities. It is an early morning or late afternoon feeder, but females will take a bloodmeal at night under artificial illumination. Human blood is preferred over other animals with the ankle area as a favored feeding site. Adults frequently reside in dwellings in darkly lighted closets, cabinets, or cupboards. Ae. aegypti is reported to fly only a few hundred yards from breeding sites.
Seasonality
The species is summer-active in the north and active all year in the south. Unlike some other Aedes spp., Ae. aegypti does not overwinter in the egg stage in colder climates, but southern populations remain reproductively active during winter and are periodically inactive during cold periods. Adults are killed by temperatures below freezing and do not survive well at temperatures below 5 degrees Celsius. Longevity is affected by larval nutrition, temperature and humidity. On average, females live up to a month, but males die sooner.
Dr. Womack is a Professor of Biology at Macon College, Macon, Georgia