The layperson should learn to recognize the difference between eggs, larvae (wigglers), pupae (tumblers) and adults. Only trained specialists can tell the difference between mosquito species. However, knowing what species is causing the problem can be of great benefit in planning control. Some of the most troublesome mosquitoes in Ohio and their habits are listed below.
Aedes canadensis
This dark mosquito has the tarsi banded with white at both ends of the segments. It is a serious pest in woodlands. This species overwinters in the egg stage and is one of the first mosquitoes to appear in early spring. Larvae breed in woodland pools filled by melting snows or by spring rains. It shows preference for pools with a bottom of dead and decaying leaves, although it is sometimes found in roadside puddles, sink holes, wooded swamps, etc. There is one generation per year with the adults living for several months. Eggs are laid singly on the ground or above the waterline in woodland pools. Eggs hatch only after they have been flooded. Eggs are able to survive long periods of drying. Biting occurs most frequently during the evening hours, but can occur during the day or night. Aedes canadensis is a secondary vector of LaCrosse encephalitis in Ohio.
Aedes triseriatus (TreeHole Mosquito)
These black mosquitoes have silvery white scales at the sides of the thorax. They breed principally in tree holes, tires and other artificial containers. The bites are painful and sometimes very troublesome in the woods. They do not wander far from the breeding places. Larval development is rather slow with nearly a month required to reach maturity. Aedes triseriatus is the principal vector of LaCrosse encephalitis in Ohio. This species has several generations a year and overwinters in the egg stage.
Aedes trivittatus
The upper surface of this mosquito's thorax is marked with two conspicuous whitish stripes. It is a fierce biter and can be extremely annoying. Larvae occur mostly in floodwater pools and temporary rain pools. Young larvae feed at the water surface with later instars spending most of their time concealed in the vegetation at the bottom of the pool. Larvae are seldom encountered, even though adults can be present in large numbers. Adult emergence begins about eight days after hatching. Adults rest among shaded grasses and other vegetation during the daytime but bite if disturbed. They bite mostly in the evening and do not migrate far. This species overwinters in the egg stage.
Aedes vexans
A mediumsized brown mosquito, it has narrow rings of white scales on the hind tarsi and a "V" shaped notch at the middle of each band of white scales on the upper surface of the abdomen. This mosquito is very abundant and breeds in rain pools, flood waters, roadside puddles and most all temporary bodies of fresh water. Eggs are laid on the ground above the water line, hatching when flooding occurs. Larvae can be found in huge numbers. In receding water, up to 500 or more larvae are found to each pint of water. Development of the aquatic stages requires ten days to three weeks, depending on the temperature. Adults fly long distances from their breeding places with flights of five to ten miles being rather common. Adult females are vicious biters and are especially annoying at dusk and after dark. Adults live for nearly two months and are attracted to light. They rest during the day in shaded grass and other vegetation. Aedes vexans overwinters in the egg stage. It is considered the principal pest mosquito in Ohio and in many parts of the United States. It may also be a secondary vector of the Eastern equine encephalitis virus.
Anopheles quadrimaculatus (Malarial Mosquito)
These large, dark brown mosquitoes have four dark spots near the center of each wing. The tarsi are entirely dark. Eggs are laid singly on the water surface with lateral floats to keep them at the surface. One hundred or more eggs are laid at a time. A single female may lay as many as 12 batches of eggs and a total of more than 3,000 eggs. This species is the most important vector of malaria attacking humans in the eastern United States and can be found frequently in houses and other shelters. Their bites are less painful than many other mosquitoes and often go unnoticed. These mosquitoes breed chiefly in permanent freshwater pools, ponds and swamps that contain aquatic vegetation or floating debris. Common habitats include borrow pits, sloughs, city park ponds, sluggish streams and shallow margins of reservoirs and lakes. During the daytime, adults remain inactive, resting in cool, damp, dark shelters such as buildings, caves, under bridges, etc. Feeding occurs at night. These mosquitoes enter houses to feed on humans. Cows, horses, mules, pigs and chickens are also attacked. Adults fly about one half mile from their breeding site but are not taken in light traps in great numbers. Breeding occurs throughout the summer months, with overwintering taking place as an adult fertilized female.
Coquillettidia (Mansonia) perturbans
The scales on the wings of this mosquito give the wings a "peppered" appearance. The mosquito also has a rounded abdomen and white bands on the tarsi and proboscis. It breeds in permanent water, especially marshes with emergent plants. Larvae and pupae attach to the roots and underwater stems of a wide variety of aquatic plants, most commonly cattails (Typha sp.). Overwintering occurs as larvae in mud. There may be more than one generation produced in a year. There is usually a very large emergence of adults in May, with the population peaking in June and declining through July and August. It is primarily a mammal feeder and readily attacks humans. This species can fly long distances from its breeding site and is primarily a pest species in Ohio. It has been shown to be involved in the transmission cycles of California group viruses, Eastern equine encephalitis virus, and dog heartworm in other areas of the U.S.
Culex pipiens pipiens (Northern House Mosquito)
These brown mosquitoes of medium size have cross bands of white scales on the abdominal segments, but are without other prominent markings. They commonly enter houses. This mosquito is a vector of St. Louis encephalitis. Breeding occurs in rain barrels, tin cans, tires, stormsewer catch basins, street gutters, polluted ground pools, cesspools, open septic tanks, etc. Eggs are laid in clusters of 100 to 400, known as egg rafts, which float on the water surface. Hatching occurs in a day or two in warm weather, and from eight to ten days are needed for completion of the larval and pupal stages. In cooler weather of early spring or late fall, two weeks or more may be required. Breeding continues throughout the warm months of the year. One subspecies can survive and produce fertile eggs without a blood meal. This mosquito does not fly far, except when great numbers are produced. Adults are active only at night and can be found resting during the day in and around houses, outbuildings and various shelters near their breeding places. They are readily attracted to carbon dioxide (CO2) baited light traps. This mosquito overwinters as a fertilized adult female.
Psorophora ciliata (Gallinipper Mosquito)
This is a very large (almost 1/2 inch long), yellowishbrown, floodwater mosquito with shaggy legs (long erect scales on the hind tibiae). It is a vicious biter presenting a rather terrifying appearance due to its large size. When present in numbers, it is a severe pest, attacking during the daytime as well as in the evening. It is not known to be a vector of human disease. Eggs are laid on lowlying dry land (withstands drying), but hatch quickly during flooding conditions. Larvae develop rapidly and feed on other aquatic insects including mosquito larvae. Fourth instar larvae may consume three or four other larvae in one day. Larvae are easily recognized since they are two to three times as large as most other mosquito species. They hang almost straight down from the water surface. This mosquito overwinters in the egg stage.