''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
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
,
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
,
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
, and
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
.
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. 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. This species is commonly found in habitats such as grassy pools, partially shaded woodland pools, roadside ditches, and cultivated fields.
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. In temperate regions, larvae are present from April to September, and adults are active from May to October.
Medical importance
''A. vexans'' is a recognized vector for several pathogens:
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Dirofilaria immitis (dog heartworm), transmitted to canines.
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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.
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Myxomatosis, a viral disease fatal to rabbits, though ''A. vexans''’ role as a vector is less definitive and may be region-specific.
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West Nile virus
West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family ''Flaviviridae'', from the genus ''Flavivirus'', which also contains the Zika virus, dengue virus, and yellow fever virus. The virus ...
, affects mainly birds, humans and horses; found in mosquitoes collected in the UK in 2023, published in May 2025.
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.
During summer, trap collections can yield up to 8,000 individuals per night.
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.
Additionally, ''A. vexans'' harbors insect-specific viruses, including Chaoyang virus and ''Aedes vexans'' Iflavirus,
which do not affect humans or other vertebrates but are of interest in virological studies.
References
External links
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{{Authority control
vexans
Insects described in 1830