Aedes (Ochlerotatus) dorsalis
Aedes dorsalis is often referred to as the "blonde" mosquito due to the white/pale scales that cover the abdominal segments. Each segment of the abdomen also has two dark spots. These characteristics are easily noted without magnification of the specimen. This is a widely distributed mosquito in the United States ranging from the northeast to the Pacific coastal states. It is also common in the southern half of Canada, northern Africa, and northern Europe and Asia.
This species is typically a plains and prairie mosquito that is well adapted to laying eggs in small depressions that are prone to flooding, making this a "floodwater" species. These mosquitoes produce one batch of eggs then perish after oviposition. While normally associated with the plains, this species has also been found breeding in tidal marshes and around the edges of the Great Salt Lake. Aedes dorsalis overwinters in the egg stage of its lifecycle.
Aedes dorsalis is quite a pest species and is known as a vicious biter. They will feed any time of the day, but increased rates in the early evening and on calm, cloudy days. If the female is disrupted while feeding, she will immediately go back to the animal she was feeding upon or one next to it. They are persistent feeders and will continue to attempt to feed until they are full. Large mammals (horses, cows, deer, humans) are preferred hosts, but if mammals are not present, large birds can also be hosts.
Aedes (Ocherlotatus) triseriatus
Aedes triseriatus is a very interesting mosquito species along with Ae. hendersoni and Ae. trivittatus. One of the reasons this mosquito species is unique is that it tends to breed in "natural containers," primarily tree holes. It is native to the United States and Canada but has also recently become an invasive species in Europe. Because of its unique breeding habits, the highest populations tend to appear in forests or communities with very large and old trees that provide holes in trees either caused by loss of branches or animal disruption. This species has also been discovered to breed in artificial containers such as old tires and cans. Even though this population breeds in older tree holes, the species itself may be found in areas without these breeding grounds due to wind carrying adult females from hatch sites to other locations.
Feeding habits of Ae. triseriatus in North Dakota tends to focus on mammals ranging from rabbits to deer, horses, and cows. They tend to feed primarily in the mornings and early evenings, but rarely in the daytime unless disturbed from their resting grounds. Females searching out blood meals typically do not stray far from the areas they hatched in unless wind carries them away.
This species tends to appear later in June/July and is likely due to rains in June filling tree holes with water. The species overwinters as eggs in the above-mentioned containers. While the tree holes may get low on water, this species has been shown to survive on damp substrate for two or more weeks to survive until rain refills the container. Multiple stages of larvae are often seen in these containers, likely due to the height they are placed in the container.
This species is identifiable by having very dark, unbanded legs with the presence of white/cream colored triangles of scales on the pleural tergites of the abdomen.
Aedes vexans
Aedes vexans is one of the most prevalent mosquito species found in North Dakota, especially in the Red River Valley. Ae. vexans is highly adaptable to living in various conditions and can be found in urban settings, farm/ranch lands, riparian, and forested ecosystems. It is no surprise that this species is found throughout the United States and most of Canada. According to the Walter Reed Biosystematics Unit, Ae. vexans can be found in North and Central America, Africa, Europe, Asia, and Australia. (Link to WRBU: https://wrbu.si.edu/vectorspecies/mosquitoes/vexans)
This species, besides being present almost everywhere, is often the most populus of the mosquito species. It prefers to feed on mammals (cows, deer, humans) and thus the name is appropriate (to vex: annoy, injure, harass). In regions with cold climates, Ae. vexans overwinters in the egg stage of its lifecycle. This mosquito is classified as a "floodwater" mosquito, and does not lay eggs in the water, but prefers to deposit eggs along the banks of ponds or in soil found in ditches or depressions that are prone to flooding. When water levels increase after spring flooding or rain events, the eggs are submerged and begin to hatch.
Aedes vexans is multivoltine in the state of North Dakota with multiple hatching events present throughout the mosquito season. In the spring season, eggs will begin to hatch when water reaches approximately 40-50F and begin their larval development. In North Dakota this species occurs from approximately mid-May through September/October, but drastically declines after the first couple frost events.
The adults of this species can be identified by their black legs with narrow, white basal bands on their tarsi. Their abdominal segments tend to be black with a white/cream color scalloped pattern. Because these are floodwater mosquitoes, they also have a pointed terminal abdominal segment.
Anopheles earlei
Anopheles earlei can be found throughout most of Canada and the northern region of the United States. Females resemble Anopheles quadrimaculatus in their dark coloration, however, An. earlei tend to be more brownish. They often will have dark spots on their wings, but maybe the easiest distinguishing feature is the silver to copper-colored scales that produce a fringe effect on the apex of the wing.
The adult inseminated unfed females are the overwintering stage of this species lifecycle. Females overwinter in burrows of other animals, beneath houses, under porches, wells, and culverts. They have been described as persistent and annoying biters who attack man readily, even during daylight hours. The species prefers to feed on medium sized mammals up to the size of deer and does not show interest (or low interest) in birds or reptiles.
Anopheles quadrimaculatus
Anopheles quadrimaculatus is one of the more common anopheline mosquito species found in North Dakota. The range of An. quadrimaculatus in the United States extends from Florida up through Maine and across to the central region of the country. North Dakota down through Texas appears to be the western limit of the species.
The species is primarily dark in color and lacks any palp or leg banding. The wings are mainly clear with black scale lined veins and four distinct black patches. Much like other anopheline species, the palps are approximately as long as the proboscis.
The overwintering stage is the unfed, inseminated adult female. Females will overwinter in barns, culverts, animal burrows, hollow trees, and cellars. Females awaken in the spring and will acquire a bloodmeal. While preferring to feed on cows, horses, and deer, An. quadrimaculatus will also feed on humans, birds, and at times snakes and turtles. Females will lay eggs singly on the water's surface only a few days after taking a bloodmeal. They may produce multiple clutches of eggs during the mosquito season.
Coquillettidia perturbans
Coquillettidia perturbans is also known as the cattail mosquito. This species is often associated with bodies of water that contain this freshwater plant. Female mosquitoes will lay eggs in rafts on the waters surface, making this a standing water species of mosquito. Rafts may contain up to around 200 eggs and are placed primarily by stems of vegetation. Both larvae and pupae will attach themselves to aquatic vegetation and obtain oxygen through plant tissues.
This mosquito tends to overwinter in larval stages attached to the stems and/or roots of cattails. In the spring as temperatures increase, the insects break diapause to continue their development. This is also demonstrated by the fact these mosquitoes appear as questing females in early to late spring.
In terms of feeding habits, Co. perturbans seems to prefer mammals but will also feed on birds and amphibians. During the day they tend to rest in low vegetation and will feed in the evenings throughout the night. They will also feed during very cloudy days.
Coquillettidia perturbans is often referred to as a "hairy" mosquito due to the presence of a large number of setae covering the body as well as broad scales that cover their wings, much like scales of a butterfly. They have mixed dark and light scales that cover the wings, proboscis, and have large bands on their legs. Because they are standing water mosquitoes, they will also have a rounded abdomen.
Culex pipiens
Culex pipiens in most of the United States is known as the common house mosquito. Interestingly enough, in North Dakota, this species is not found in high numbers across the region. In fact, in some locations it is rarely found. In Traill and Steele counties there are at least patches where is this species is in extremely low numbers and may not have breeding populations. These patches are often associated with dense forests away from human occupancy. Worldwide, this species can be found in the upper portion of the United States, northern regions of Africa, and from Europe across to Asia.
This species is often implicated in the spread of viruses such as West Nile virus, however in eastern North Dakota, this species population spikes in June, while cases of West Nile in the state tend to appear in July and August. One of the reasons this species is associated with the transmission of West Nile is because this species of mosquito appears to prefer blood from avian hosts but will also take blood from mammals.
Culex pipiens, like Cx. tarsalis, overwinter as inseminated females that stow away in homes, attics, crevices in trees and/or buildings. It tends to be anthropophilic and likes urban settings or places with human made structures. They will breed in standing water locations even if that water is only temporary. In fact, egg rafts have been collected in water troughs, tires, flowerpots, and buckets of water…in very large numbers.
Culex pipiens looks similar to Cx. tarsalis in that it has a rounded terminal abdominal segment, but it does not have any leg bands and it also lacks the ring around the proboscis that is seen in Cx. tarsalis.
Culex tarsalis
Culex tarsalis is one of the most prominent "standing water" mosquitoes found in North Dakota. This species has been found in open farmland, forested sites, urban communities, and anywhere long-term temporary standing water is available. The distribution of this mosquito tends to be from the southeastern region of the United States then continues north and west throughout the entirety of the United States and Canada.
The highest prevalence of this species is throughout the southern region of the Great Lake states, and the midwestern states of Nebraska, South Dakota,
and North Dakota up into Canada. Populations of Cx. tarsalis are also high within California according to the Parasites and Vectors website
https://parasitesandvectors.biomedcentral.com/
articles/10.1186/s13071-021-05051-3/figures/3)
Culex tarsalis females will mate in the fall, then overwinter as inseminated adults. During the spring they will seek out a blood meal to provide nutrients for egg development. While numbers of Cx. tarsalis may appear in small proportions in late May and early June, their peak tends to arrive in July and August. This species can be multivoltine, with early populations contributing eggs/larvae into the peaks later in the summer.
This species may be considered an opportunistic feeder as it will take bloodmeals from both avian hosts (American Robins, Common Grackles) as well as mammals (deer, horses, humans). This interesting blood feeding habit unfortunately makes this species one that has a higher potential for zoonotic transmission (transmitting diseases/viruses from animals to humans and vice versa). Most associated with this type of feeding habit is the spread of West Nile virus and it is shown that in North Dakota the main culprit is Culex tarsalis.
Identifying features of this mosquito are quite unique and easy to pick out even for someone who is not trained in mosquito identification. Key characters include a rounded terminal abdominal segment, a distinct white band round the proboscis, and legs that show broad apical and basal bands on the tarsi.
Culiseta inornata
Culiseta inornata is one of our "early risers" in North Dakota. Not only is this mosquito species out early in the spring, but it is also one of the largest mosquitoes found in the region. This is largely due to the fact that in the later part of summer the females will mate, then overwinter inseminated. These mosquitoes will awaken often when snow is still on the ground, but air temperatures rise above 50F. They will then take a blood meal and produce eggs. Eggs will be deposited on the surface of open water even if patches of ice remain.
This species of mosquito tends to feed on large mammals including deer, horses and cows but may also attack humans. Cu. inornata is similar in size, reproductive behaviors, and the feeding habits of Aedes excrucians, however, typically in smaller numbers.
Culiseta inornata will typically be found in areas of permanent to semipermanent bodies of water due to the longer development times of their larvae in cold water conditions.
As mentioned, Cu. inornata is a large-bodied mosquito that sometimes can be confused with smaller cranefly species. The most obvious difference is the presence of a proboscis used for feeding on blood. The coloration of this mosquito may vary, however the most common is a light golden-brown coloration of scales that cover the body. They do not possess leg bands and they do not have a ring around their proboscis. The scales on the wings and body are narrow, which makes identification between Cu. inornata and Co. perturbans simple.
