Search
(Diptera: Culicidae)
Madeline Phillips, Chris Carlton
Aedes vexans or the inland floodwater mosquito is a “cosmopolitan” pest species, which means that it is present in nearly every country. Adults of this species are about 7 mm in length, but males can sometimes be smaller. Specimens are dark gray or black in color and feature stripes along their abdomens. Each of the six legs has a white band around the end of each segment. Abdominal segments are covered with scales. When viewed from the side these scales form a B-shape that repeats down the abdomen of the mosquito. This B-pattern is diagnostic and allows the species to be distinguished from similar mosquitoes. As is typical of mosquitoes, an elongate piercing/sucking proboscis is present. Antennae are slender on females and feathery (plumose) on males. The third (hind) pair of legs are held in an elevated posture in resting position. Larvae, also known as wrigglers, can range from 1.5 mm to 7.7 mm in length. Larval abdomens are largely clear with a brown center and long, fine hairs (setae) on each segment. Species identification of both larvae and adults requires technical expertise of a taxonomist or mosquito specialist.
Aedes vexans adult female (iNaturalist user MartinGalli, Creative Commons 4.0).
The life cycle of Aedes vexans is similar to that of other Aedes mosquitoes. The female deposits eggs in any container containing water, and the eggs typically stick to the walls of the container and resemble clumps of dirt. Eggs can remain for days or even months depending on location and circumstances. Some can survive during winter in southern states of the U.S. Eggs can hatch into larvae in as little as a few days under optimal conditions of moisture and temperature but must be properly submerged in water for this to occur. Larvae are fully aquatic during development and are filter feeders on microorganisms in the water. Larvae transform to pupae in as little time as five days and remain in the water. Adults emerge after two or three days and fly away in search of a blood meal (females) or nectar source (males). Within seven to 10 days, females are capable of laying eggs and the process repeats.
Aedes vexans get their name from the Latin word “vexāre” which means to annoy or harass. They are confirmed to be the vector of Tahyna virus and dog heartworm but are also thought to be potential vectors of West Nile virus, Zika and Eastern equine encephalitis. The species is among the most widespread mosquitoes in the world.
Aedes vexans females display aggressive and persistent biting behaviors and can be present in large numbers when weather conditions favor larval development, especially during periods of heavy rain during warm weather. Travel of up to 10 miles in search of a blood meal has been documented, in contrast to other mosquito species, which typically do not disperse far from larval habitats.
Monitoring and prevention. The best way to prevent bites before they happen is to wear protective clothing. When entering mosquito-dense areas, wearing long-sleeved shirts, pants and tall socks is the most effective way of preventing bites. Full window screens or mosquito netting when sleeping outdoors are necessary and effective in preventing mosquito entry.
Natural control and sampling. Removal of standing water prevents mosquito development but must be done across wide areas for this species. Keeping lawns cut short and trimming shrubbery reduces resting spots for adult mosquitoes. Mosquito sampling is typically done using carbon dioxide baited traps for adults and monitored water sources for larvae.
Chemical control. Applying effective mosquito repellent (typically DEET or picaridin-based compounds) to exposed skin and thin clothing when going outdoors is the best way to reduce personal risk of mosquito bites. Floating mosquito dunk formulations of the bacterial insecticide Bacillus thuringiensis israelensis are commonly used for small bodies of water. These specifically target mosquito larvae. When conducting homeowner treatments for pests, always follow legally mandated label instructions. Large infestations of adults and extensive larval habitats require treatment by professionals using chemicals that are labeled for mosquitoes.
CDC. 2022. Life Cycle of Life Cycle of Aedes aegypti and Ae. albopictus Mosquitoes. (accessed March 20, 2024).
Iowa State University Bug Guide. 2019. Inland Floodwater Mosquito. (accessed March 19, 2024).
MediLab Secure. Aedes vexans. (accessed March 20, 2024).
The Green Advantage. 2023. The Inland Floodwater Mosquito. (accessed March 20, 2024).
VDCI. 2024. Exploring Mosquito Species: Aedes Vexans. (accessed March 19, 2024).
Contact Us: For advice about pest identification or diagnosis, contact the LSU AgCenter Department of Entomology. Reach the department through the Contact Us webpage.
P4012
9/11/2025
The LSU AgCenter and LSU provide equal opportunities in programs and employment.
