Mosquitoes of North America - Species Profile: Aedes vexans

 Aedes vexans (Meigen 1830), subgenus Aedimorphus.

Common names: Inland Floodwater Mosquito, Common Floodwater Mosquito

Aedes vexans
Photo by author in Richmond County, Georgia 

        One of the most abundant and widespread species of mosquito worldwide, Aedes vexans breeds in a plethora of different water body types, but is most common in floodwater pools and ditches. Females lay eggs in shallow pools of water above moist leaves and soil, where the eggs may lay dormant for months after the pool dries before a rain event creates a new puddle for the eggs to hatch and larvae to develop. Quite cosmopolitan, this mosquito is found on every continent except Antarctica and South America and ranges in every state, province, and territory in the USA and Canada. Aedes vexans may be a vector of West Nile, Triple E, and canid heartworm disease. Blood hosts include birds and mammals.

        Aedes vexans can be differentiated from other Aedes mosquitoes by the presence of very narrow bands at the base of each tarsal segment. The only other Aedes mosquito in the US and Canada with tarsal banding as narrow is Aedes cantator, which has broad bands on the abdominal terga that connect with the white patches on the sides of the abdomen. The bands on the abdominal terga on Ae. vexans are double-lobed, like a white "B" and do not connect with the patches on the side of the abdomen. The scutum of this species is unpatterned and a dull gray-brown, unlike Aedes cantator which is reddish-brown in coloration. Other mosquitoes that may have narrow tarsal banding are Culiseta sp., which have a blunt abdomen as opposed to the tapered abdomen with exposed cerci that Aedes exhibit.

Photo by Sergei Drovetski on iNaturalist

Photo by David Enrique on iNaturalist

Sources

Burkett-Cadena, N. D. (2013). Mosquitoes of the Southeastern United States. Tuscaloosa, AL: The University of Alabama Press.

Darsie, R. F., and Ward, W. A. (1981). Identification and Geographical Distribution of the Mosquitoes of North America, North of Mexico. Fresno, CA: American Mosquito Control Association.

Weissmann, M. 2016. Mosquito of the Month: Aedes vexans - the Inland Floodwater Mosquito. Vector Disease Control International, blog post.

Mosquitoes of North America - Species Profile: Aedes cinereus

 Aedes cinereus (Meigen 1818), subgenus Aedes.

Common names: Minute Floodwater Mosquito, Small Woodland Mosquito

Aedes cinereus
Photo by @melodi_96 on iNaturalist

        A widespread woodland mosquito, this species breeds in ephemeral pools across much the Northern Hemisphere. In the United States, it can be found from Georgia north to the Arctic Circle. In southwestern states, Aedes cinereus is only found in higher elevation regions where snowmelts may provide breeding locations. The species is largely absent in Texas, Arizona, most of New Mexico, low elevation regions of California, and Vancouver Island in British Columbia. Where it does occur, this mosquito feeds mostly on mammals.

        

        Quite distinct in its uniformity, Aedes cinereus can be differentiated from other Aedes species by its unmarked brown scutum, lack of tarsal banding, and white connected patches of scales on the side of the abdomen that form a single, unbroken white stripe.

        

Sources

Burkett-Cadena, N. D. (2013). Mosquitoes of the Southeastern United States. Tuscaloosa, AL: The University of Alabama Press.

Darsie, R. F., and Ward, W. A. (1981). Identification and Geographical Distribution of the Mosquitoes of North America, North of Mexico. Fresno, CA: American Mosquito Control Association.

Mosquitoes of North America - Species Profile: Aedes canadensis

     Aedes canadensis (Theobald 1901), subgenus Ochlerotatus.

Aedes candensis ssp. canadensis
Photo by author in Nacogdoches County, Texas

        This seasonally common species is found throughout the eastern and central United States and Canada, spreading northwest from the dustbowl region into Canada and Alaska. A woodland inhabitant, Aedes canadensis reaches peak activity in mid-summer evenings. Eggs are laid in wet depressions in forest soil that fill with water in fall and winter and remain until spring. 

        Superficially similar to the abundant Aedes vexans, this species can be differentiated from the latter by the white bands on the tarsi (legs): in Ae. vexans the bands are basal only, located at the beginning of each tarsal segment, and very narrow; Ae. canadensis has usually broad white tarsal bands that cross the tarsal joints (making the bands basal and apical - i.e. located at the beginning and end of each tarsal segment). Ae. vexans also differs from Ae. canadensis by the presence of a double-lobed pattern on the abdominal terga (top portion of abdominal segments), which the latter species lacks. 

Other Aedes mosquitoes with basal and apical tarsal banding include the Aedes dorsalis group (Ae. dorsalis, melanimon, and campestris), which have broad, contrasting scales on the wings, subgenus Georgecraigius mosquitoes (Ae. atropalpus, epactius, and fluviatilis) and Jarnellius (Ae. sierrensis and monticola), which are tan and black patterned on the scutum and have a pale patch of scales at the base of wing vein C, and Aedes togoi (restricted to WA, BC), which has a distinct lyre-shaped pattern on the scutum.

        There are two subspecies of Aedes canadensis, A. c. canadensis which is the dominant subspecies and exhibits broad tarsal banding, and A. c. mathesoni, sometimes classified as a separate species, which has narrow tarsal banding and is only found in the Southeast on the coast and in the coastal plain of Alabama, Georgia, Florida, and South Carolina.

Aedes candensis ssp. canadensis
Photo by @apistopanchax on iNaturalist

Aedes candensis ssp. mathesoni
Photo by @richardthecrittercatcher on iNaturalist

Sources

Burkett-Cadena, N. D. (2013). Mosquitoes of the Southeastern United States. Tuscaloosa, AL: The University of Alabama Press.

Darsie, R. F., and Ward, W. A. (1981). Identification and Geographical Distribution of the Mosquitoes of North America, North of Mexico. Fresno, CA: American Mosquito Control Association.