Aedes vexans

Aedes vexans, commonly known as the inland floodwater mosquito or tomguito, is a widespread and frequently encountered pest mosquito with a cosmopolitan distribution, occurring across North America, Europe, Asia, and Africa.^[1]

Aedes vexans
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Family:	Culicidae
Genus:	Aedes
Subgenus:	Aedimorphus
Species:	A. vexans
Binomial name
Aedes vexans (Meigen), 1830

Description

The adult female A. vexans is characterized by a bandless proboscis with white ventral scales, short, brown scales on the scutum, and B-shaped markings (when viewed from the side) on each abdominal tergite.^[2] Only females take blood meals, showing a preference for humans and cattle, while males feed exclusively on nectar, honeydew, and sap—sources that females also utilize, though infrequently.^[3] This species is commonly found in habitats such as grassy pools, partially shaded woodland pools, roadside ditches, and cultivated fields.^[4]

Lifecycle

After a blood meal, the female A. vexans deposits her eggs in areas prone to flooding, where they remain dormant until inundated, triggering hatching.^[5] In temperate regions, larvae are present from April to September, and adults are active from May to October.^[4]

Medical importance

A. vexans is a recognized vector for several pathogens:

• Dirofilaria immitis (dog heartworm), transmitted to canines.^[6]
• Tahyna virus, a Bunyaviridae virus affecting humans in Europe, causing fever that typically resolves within two days but may progress to encephalitis or meningitis in rare cases.^[7]
• Myxomatosis, a viral disease fatal to rabbits, though A. vexans’ role as a vector is less definitive and may be region-specific.^[8]
• West Nile virus, affects mainly birds, humans and horses; found in mosquitoes collected in the UK in 2023, published in May 2025.^[9]

In Europe, A. vexans is the predominant mosquito species, often accounting for over 80% of the mosquito population in certain areas, with abundance tied to floodwater availability.^[10] During summer, trap collections can yield up to 8,000 individuals per night.^[10] The species has demonstrated a higher transmission efficiency for Zika virus compared to A. aegypti, enhancing its potential as a vector in northern latitudes beyond the range of primary vectors A. aegypti and A. albopictus, due to its wide distribution, periodic high abundance, and aggressive human-biting behavior.^[11]

Additionally, A. vexans harbors insect-specific viruses, including Chaoyang virus^[12] and Aedes vexans Iflavirus,^[13] which do not affect humans or other vertebrates but are of interest in virological studies.