There are 52 mosquito species found in Massachusetts; some are common, and others are found less frequently. Each species has it's own unique combination of characteristics. The presence of a particular mosquito species is dependent on the type of nearby wetland or habitat. Examples of different habitats that produce different mosquito species include permanent swamps, temporary woodland pools, river flood plains, cattail swamps or artificial containers. The last item can be almost any container which can hold stagnant water for at least a week in the summer, including roadside highway drains, old rimless tires, unused swimming pools, uncovered empty trash cans, and bird baths.
The species of mosquito found at any one time in an area is dependent on temperature and season; there are early spring, late spring, summer, and mid-summer species. Some mosquito species have several generations each summer, so their populations increase as the summer goes along. Most mosquito species are active primarily during dusk and dawn or during cloudy warm days. However, one local species is active all night and some species will bite during hot sunny days. Three of our local mosquito species will enter protected shelters such as houses, and it is usually one of these three species that annoy people while they are trying to sleep.
While some mosquitoes are indiscriminate about what they bite, most are selective. Some of our mosquito species feed primarily on humans and other mammals, while others mostly bite birds, and still others feed on amphibians (such as frogs) or reptiles (such as snakes). Some species are very aggressive and persistent, while others are very shy. Finally, some deliver a more annoying bite that results in more itching.
The chance of acquiring a mosquito-borne disease in Massachusetts is extremely rare. However, the species which are believed to transmit Eastern Equine Encephalitis include some of the most numerous species, which on given nights can be caught on any suburban or rural property in eastern or central Massachusetts. West Nile Virus has been introduced into our area in the year 2000, and continued research is showing many species of mosquito, including human biters, adept at carrying and possibly transmitting this disease. Mosquitoes also transmit animal diseases, and the probability of a pet dog or cat acquiring heartworm is not so remote. It is recommended that a veterinarian monitor your pet and administer the proper preventative medication.
Read the "Discovery of New Mosquito Species in Massachusetts" Press Release from July 16, 2000, regarding the Aedes japonicus japonicus mosquito species.
Mosquito ID cards produced by staff at CMMCP are available for certain species; click on the underlined species name for a pictorial ID.
- Aedes albopictus — Aedes albopictus was first collected in the United States at a tire dump near Houston, TX in 1985. The species spread rapidly through the southern United States and has been documented in over 25 states over the last decade. The first record of this species in Mass. was documented in 2000. Aedes albopictus is a multi-voltine species and should have a seasonal distribution similar to that of Ochlerotatus triseriatus. Ae. albopictus is an opportunistic container breeder that is capable of utilizing natural as well as artificial container habitats. Although the mosquito is most often associated with discarded tires in this country, it has the ability to adapt to an exceptionally wide range of confined water sources. The mosquito is known for its ability to survive in very small collections of water, requiring only 1/4" of depth to complete its life cycle.
- Aedes cinereus — Common late spring and early summer mosquito pest of humans and other mammals. Larvae are found in late April and May in tussock and leather-leaf marshes. Aedes cinereus is a univoltine species that hatches in greatest numbers during the month of May. Egg hatch is staggered, however, and specimens can be collected well into the month of June. The species may reappear during the summer and relatively large populations can be found following heavy rains in August and September.
- Aedes vexans — Very common summer mosquito. This pest of humans and other mammals can have several generations each season, so the population may increase during the summer. Larvae are found in a wide variety of temporary pools and wetlands. This mosquito is a suspect in the transmission of EEE from birds to humans. After significant rain events, this mosquito can be quite numerous and is considered a major pest of man.
- Anopheles barberi — A tree hole habitat mosquito in eastern North America. The larvae are predators of other mosquito larvae. It has been shown to be a vector of malaria in the laboratory, but it is not thought to be an important malaria vector in the wild.
- Anopheles crucians — A mosquito that develops in semi-permanent and permanent pools, ponds, lakes and swamps. It may be a vector for malaria in certain areas.
- Anopheles earlei — Larvae are found in cold, clear water at the margins ponds and pools containing emergent and floating vegetation. They are also found in woodland pools, bogs, marshes and along sluggish streams. Females are dusk- and early-evening biters and will enter houses to bite.
- Anopheles punctipennis — Found occasionally in the spring and summer. This pest of humans and other mammals has a mildly annoying bite. The larvae are found in a wide variety of wetlands including permanent swamps and along the edges of ponds and slow moving streams.
- Anopheles quadrimaculatus — Common summer mosquito. A pest of humans and other mammals that readily enters houses and has a mildly annoying bite. The population increases during the summer. The larvae are found in clear water amongst low vegetation or floating debris, in permanent swamps, and along the edges of ponds and slow moving streams.
- Anopheles walkeri — The larvae of this species occur in fresh-water marshes containing emergent or floating vegetation. It is reported that cut-grass shaded by willows or button bushes off the most ideal larval habitat. Adults have been found resting in dark extremely moist situations, particularly around the shaded bases of cut-grass and other shore-line shrubbery.
- Coquillettidia perturbans — Very common mid-June to mid-August mosquito. An indiscriminate pest of birds, humans and other mammals that is known to be a vicious biter, and will readily enter homes. The larvae are unusual in that they are found attached to the submerged roots of cattails and a few other aquatic plants. This trait makes this species impervious to control using some pesticides that are effective against larvae of other species. This mosquito is suspected in the transmission of EEE from birds to humans.
- Culex erraticus — Culex erraticus is a competent vector of Eastern equine encephalitis virus, and both St. Louis encephalitis virus and West Nile virus have been isolated from field-collected specimens. Previous bloodmeal analysis studies have shown this species to be a generalist, feeding on a variety of mammals, birds, reptiles, and amphibians. This behavior can bridge arboviral transmission across different vertebrate groups.
- Culex pipiens — Very common year round mosquito which primarily feeds on birds. It will readily enter a house, but is considered shy. It will typically only bite people when they are motionless, usually while they are sleeping. The larvae are found in water holding containers and in polluted waters. Culex pipiens are considered the primary vector of West Nile Virus.
- Culex restuans — Culex restuans has a distribution that ranges from central Canada south into Mexico. The mosquito is very common in the eastern and central United States. Culex restuans undergoes a life cycle that is typical for domestic Culex. Inseminated adult females enter hibernation in fall and pass the winter in a period of quiescence. Culex restuans utilizes an exceptionally wide range of larval habitats. The water used by this species can vary from nearly clear to grossly polluted. Culex restuans regularly colonizes temporary ground pools that remain flooded after they have produced broods of floodwater Ochlerotatus. Culex restuans is also the first species to utilize water that collects in discarded tires. The species can often be found in tire water that is absolutely clear and devoid of leaf litter.
- Culex salinarius — Common summer mosquito. A fierce biting pest of birds, humans and other mammals which can have several generations in a summer, so the population may increase during the season. This mosquito is active all night. Larvae are found in both fresh and polluted grassy hummock areas of permanent water swamps. West Nile Virus has been isolated from this species in 2000.
- Culex territans — Culex territans is quite common throughout most of eastern Europe and is even found in parts of Africa. In North America, Cx. territans extends from Alaska and Canada south through most of the United States. Culex territans has a life cycle that is typical for most Culex species. In late fall, inseminated adult females feed on carbohydrates and hibernate in subterranean enclosures where they pass the winter in a state of torpor. The mosquitoes emerge in very early spring, obtain a blood meal and lay the first egg rafts of the season. Culex territansis a frog feeder and it is not uncommon to see this species feeding on Spring Peepers. Egg hatch, however, may be delayed because of the mosquito's unique oviposition habits. Unlike most Culex, Cx. territans females rarely deposit their egg rafts directly on the surface of the water. This mosquito normally positions the raft up on the bank and relies on rainfall or rising water levels to flush the eggs onto the water's surface. Culex territans shares habitat with many of the univoltine Ochlerotatus in early spring, a variety of Anopheles sp. later in the summer and Uranotaenia sapphirina very late in the season. The species is occasionally found in containers but cannot tolerate even moderate levels of pollution. Culex territansis common in farm ponds, swamps and bogs and roadside ditches. Culex territansis one of the few species that can be collected from streams. It is not uncommon to find larvae within the grassy margins of slow moving streams and specimens are sometimes found in rock pool habitats normally associated with Ochlerotatus atropalpus.
- Culiseta impatiens — Larvae are found in semi-permanent and shaded permanent ponds. Adults are widespread. Females overwinter as mated nullipars, and are one of the earliest emerging blood-feeders. Females are extremely long lived, surviving until late fall. Eggs are laid in rafts of about 100. There is only one generation per year. Males do not swarm, and mated pairs have been found on cave roofs. It is found throughout western and northeastern North America.
- Culiseta inornata — Larvae found in a wide range of habitats including marshes, seepages, ditches, canals ponds, etc. Larvae can tolerate water with a salinity up to 26 ppt. Biting activity on overcast days, dusk and at night. Flight range is less than five miles.
- Culiseta melanura — Common spring and summer mosquito. A bird- feeding mosquito that can have several generations per year, so the population may increase towards the end of the summer. Larvae are found in holes in the root structures of white cedar and red maple trees in swamps. This is an important mosquito species because it is believed to spread EEE virus through the bird population. This mosquito was not thought to be a mammal-biter, but recent research has shown a small percentage of it’s bloodmeals are taken from mammals.
- Culiseta minnesotae — Larvae are found in semi-permanent to permanent marshes. Females overwinter as mated nullipars, emerging in early May to feed. Eggs are laid in a raft on the water surface. Larvae hatch in mid to late May. Larvae often cluster below aquatic vegetation, often in association with Culiseta morsitans. Mating habits are unknown. Blood-seeking adults have been collected in late summer, and it is believed that the species is likely multivoltine. Females are blood feeders, preferring birds. Not known to bite man. In North America, found in across south-central Canada and the north-central states.
- Culiseta morsitans — Culiseta morsitans is a mosquito of the northern United States with a distribution that extends through Canadian Yukon Territory into Alaska. The mosquito is fairly common in New England and upper New York state. Records from the Atlantic coast region indicate that the species has been collected as far south as Delaware. Culiseta morsitans has a life cycle similar to that of the northern Ochlerotatus group of mosquitoes. The species is considered univoltine but females are long lived and frequently appear in light trap collections well into the summer. Unlike most members of the Genus Culiseta, the egg rafts are deposited on damp earth, probably deep within the Carex tussocks that are so common in their breeding habitat. Mature stands of red maple that grow in 12-18" of early spring ground water provide typical habitat. Uprooted trees are common in many of the swamps that support this species and tussocks of Carex serve as indicators of the semi-permanent nature of the habitat.
- Ochlerotatus abserratus — Very common early spring to early summer mosquito pest of humans and other mammals. Larvae are found in temporary spring pools and margins of permanent waters in April. Readily bites in shaded areas during the day.
- Ochlerotatus atropalpus — Uncommon mosquito in Massachusetts, but can be a pest of man as our data has shown. This species is known as the "rockpool" mosquito, which describes it's preferred habitat, but data from New Jersey has shown that it has become well adapted to artificial containers such used tire casings.
- Ochlerotatus aurifer — Found occasionally in the spring and early summer. Vicious biting pest of humans and other mammals. Larvae are found in the spring in open marshes.
- Ochlerotatus canadensis — Common late spring and summer mosquito. Fierce biting pest of humans and other mammals. Larvae are abundant in late spring and found occasionally during the summer in woodland pools, swamp borders and grassy hummock areas. This long-lived mosquito is the primary suspect in the transmission of heartworm to dogs and a possible suspect in the transmission of EEE from birds to humans.
- Ochlerotatus cantator — A mosquito more common in salt marsh areas, but has been collected in the Central Massachusetts area. Larvae can be found in freshwater habitat that received runoff from streets and highways that receive salt during the winter. Is considered a pest of man, but not considered common in this area. when adult samples are found, it is likely that they developed elsewhere.
- Ochlerotatus communis — Ochlerotatus communis is a true snowpool species, common throughout the northern United States and Canada into Alaska. Throughout its range, the species is associated with heavily forested areas at high elevations. Ochlerotatus communis larvae are most common in deep snowpoolsfilled with dark colored water in forested areas above elevations of 1500 ft. In most cases, Oc. communis is the only large mosquito in the pools although in some years, small numbers of another northern species, Ochlerotatus provocans, may be intermixed.
- Ochlerotatus decticus — This species overwinters in the egg stage and is considered univoltine. The larvae occur in sphagnum lined depression in open bogs.
- Ochlerotatus diantaeus — Aquatic stages live in temporary or semi-permanent water bodies, in peat bogs, forest ponds and ditches, sometimes in open marshes and rock pools. Wood et al. (1979) suggest that the long antennae of the larval stages may indicate a peculiar feeding behavior. The species is monocyclic; larvae appear in mid or late spring, stemmed from overwintering eggs. Adults emerge from May onwards to July and are present during the summer months. Females feed on mammals, including man, mainly at dusk and dawn. Transmissions of parasitic diseases to humans are not known at present.
- Ochlerotatus dorsalis — Ochlerotatus dorsalis has distribution that extends over the greater portion of North American northern Europe and into Asia. In the United States, the mosquito reaches greatest abundance from the plains states to the Pacific coast. In the east, it has been reported in lesser numbers across the Great Lakes states to the east coast states of Massachusetts, Connecticut and New Jersey. Ochlerotatus dorsalis overwinters in the egg stage and the eggs hatch after flooding during the first warm weather in the spring. Oc. dorsalis is well known for its capacity to migrate long distances. The adults are strong fliers and have been traced for 22 miles in Utah and more than 30 miles in California. As a result, the mosquito has been recognized as a chance migrant in some areas of its range. Ochlerotatus dorsalis larvae occur in a variety of habitats including both brackish and freshwater. They are found in large numbers on tidal marshes of the Pacific coast. The species is also common along the margins of the Great Salt Lake in Utah. Ochlerotatus dorsalis can be found in a variety of freshwater habitats including marshes, temporary pools formed by precipitation, natural springs and irrigation water. The larvae Oc. dorsalis have been found in association with numerous other mosquito species. In Utah, the species has been found breeding with 18 other species of mosquitoes including Ochlerotatus vexans, Culex tarsalisand Culiseta inornata. In New York, under saline conditions, the larvae have been found with Ochlerotatus sollicitans.
- Ochlerotatus excrucians — Very common mid spring and early summer mosquito pest of humans and other mammals. Larvae are found in a wide range of wetland habitats. This mosquito is a suspect in the transmission of heartworm to dogs. Isolated specimens have been found throughout the summer months.
- Ochlerotatus fitchii — Oc. fitchii is a mosquito of the northern United States and Southern portion of Canada. Its range extends from Maine to New Jersey on the eastern seaboard, west to northern Nevada and north into British Columbia. Oc. fitchii is a univoltine species with a typical northern Ochlerotatus life cycle. In Massachusetts, the single generation of eggs hatch in April and the larvae reach 4th instar during the early part of May. Egg hatch may be staggered during the early season and a variety of instars can be collected from different habitats in the same geographic area. Adults are on the wing in May, blood feed and deposit their eggs which do not hatch until the following spring. Oc. fitchii has been reported from a wide variety of habitats but the species is most common in semi-permanent bodies of water in open areas that support emergent vegetation.
- Ochlerotatus grossbecki — Oc. grossbecki is recognized as a mosquito of the southeastern United States, but the species is found in Massachusetts on occasion. The mosquito occurs at low levels throughout the more southern areas of the state. Oc. grossbecki is one of the earliest mosquitoes to hatch from overwintering eggs. Development is rapid, considering the cold water that is present in the early Spring. Oc. grossbecki is on the wing before most mosquito control agencies put out their surveillance traps, however, the species persists until early summer and can be represented in low numbers in trap collections during May and June. The larvae of Ae. grossbecki are most common in flooded woodlands where mature Red Maple and Beech are the dominant trees. Decomposing leaves add tannins to the aquatic habitat and in most cases, habitat water is so dark that a white dipper submerged more than 2 ft below the surface cannot be clearly detected.
- Ochlerotatus hendersoni — Larval habitat is water-filled treeholes in the forest canopy. The overwintering stage is the egg. Host preference is for mammals, but little is known about the biology of this rarely collected species. It is a multivoltine species, with adults seen from June – August.
- Ochlerotatus implicatus — Ochlerotatus implicatus is one of the earliest species to emerge as adults in Canada, developing in temporary snow or rain pools in woodland areas. It is one of the most widely distributed species in Canada south of the tree line, but is seldom found in high enough concentrations to be considered a nuisance. Adults tend to be short lived, and while it bites vigorously in shaded conditions during the day, its low numbers make it generally not significant. Belton (2007) does not include this species on his list of potential WNV vectors.
- Ochlerotatus intrudens — Larval habitat is temporary and semi-permanent woodland pools, marshes, bogs, and grassy drainage ditches. The overwintering stage is the egg. Host preference is mammals and the females are persistent human biters that attack during the day and night, but the species is relatively uncommon in New England. It is a univoltine species.
- Ochlerotatus japonicus japonicus — New species found in Massachusetts in 2000. This species was first found in New York & New Jersey in 1998, then Connecticut in 1999. This mosquito is native to Japan, Korea, Taiwan, and southern China. It's preferred habitat is artificial containers and discarded tire casings. It is not believed at this time to be a voracious biter of man, however research done by CMMCP has shown it can be a pest. West Nile Virus has been isolated from this species.
- Ochlerotatus provocans — Larval habitat is temporary woodland snowmelt pools, roadside ditches, swamps and bogs. The overwintering life stage is the egg. Its host preference is for mammalian blood to other potential hosts. Females bite humans readily during the day in shaded areas and in the evening in open areas. Virus isolations in Connecticut have found Jamestown Canyon Virus in this univoltine species.
- Ochlerotatus punctor — Females of this species are very similar to Ochlerotatus abserratus and can be difficult to differentiate from this other spring brood, univoltine species. Its larval habitat is in temporary woodland pools and sphagnum bogs in densely wooded mixed and coniferous forests in high elevations. Females are persistent human biters that mostly attack at dawn, dusk and early evening. They also bite during the day in wooded areas and enter houses after dark. Uncommon in New England.
- Ochlerotatus sollicitans — Very common summer mosquito found primarily along the coast. This aggressive mosquito will bite on a hot sunny day and is known to fly long distances, so it occasionally turns up in our district. Larvae are found on the edges of salt marshes.
- Ochlerotatus sticticus — The larval habitat of this species is temporary woodland pools in floodplains of rivers and large streams. The overwintering life stage is the egg. It’s a univoltine species with larvae active from May – August. Host preference is varied, from mammals and birds to reptiles. Females are aggressive human biters that may attack during daylight hours. Virus Isolations in Connecticut have shown several viruses: Cache Valley, Eastern Equine Encephalitis, Jamestown Canyon, Trivittatus and West Nile.
- Ochlerotatus stimulans — Spring mosquito that has been shown by data collection to be found well into the summer months. Has a singe generation like all spring mosquitoes, and is not considered a vector of disease at this time. Readily bites mammals, and can be a common pest in the spring.
- Ochlerotatus taeniorhynchus — The black salt marsh mosquito is a severe biter of man and livestock along the southern coasts from North Carolina to Florida and in the Caribbean. Unchecked populations can have a major economic impact. While capable of transmitting eastern equine encephalitis and St. Louis encephalitis in the laboratory, it is not a major vector of these diseases in nature. It is, however, an important natural vector of dog heartworm and Venezuelan equine encephalitis. The black salt marsh mosquito is found on the coastal plains from Massachusetts to Texas, in California along the Pacific Coast and in the Caribbean. It is more abundant in the south. This mosquito breeds in the upper regions of grass salt marshes where it is generally associated with spike grass (Distichlis spicata) and salt meadow hay (Spartina patens). In the south, production also occurs in the high marsh associated with mangroves, saltwort (Batis maritima) and glassworts (Salicornia species). It also breeds on dredge disposal islands along the Atlantic Intracoastal Waterway. During the mosquito season, a portion of each egg clutch will hatch when flooded. Productive salt marsh sites are flooded at irregular intervals by wind or lunar tides, or heavy rainfall. Bacteria and other microorganisms provide an abundant food supply. in the field, hundreds to thousands of mature larvae often form tightly clustered "balls" which are thought to be associated with feeding, Under optimal conditions, emergence of adults can occur in as little as six days following egg hatch. Host seeking occurs in the evening and to a lesser extent in the morning. Females do not seek hosts to any great extent during darkness. In daytime, hosts that move near resting females may be attacked. The black salt marsh mosquito will feed on birds as well as mammals. All populations in Florida exhibit some autogeny which refers to an ability of females to develop eggs without taking a bloodmeal. At northern latitudes, eggs enter diapause in response to decreasing day length and water temperature; breeding can occur year round in the extreme south.
- Ochlerotatus thibaulti — This species is an exceptionally early season mosquito species and fourth instar larvae can frequently be collected as early as the 3rd week of March. Larval instars are mixed during the early season, however, and in some years specimens can be taken from suitable habitat into the month of May. During the earliest portion of the season, Ae. thibaulti appears to be the only species present within the crypts that characteristically hold larvae. As the season advances, Cs. melanura becomes an associate species. In some areas, Ae. canadensis becomes common in the surrounding swamp habitat and occasional specimens sometimes enter the recesses where Ae. thibaulti are found.
- Ochlerotatus triseriatus — Common summer mosquito. A pest of humans and other mammals. Most of these larvae actually are found in old rimless tires, although some are found in other shaded artificial containers and in tree holes. When this mosquito is a pest, it's breeding source is usually close by. West Nile Virus has been isolated from this species in 2000.
- Ochlerotatus trivittatus — Common summer mosquito. Larvae are found in floodwater pools in both swamps and marshes. This pest is a persistent biter, and will even bite during the day.
- Orthopodomyia signifera — Larval habitat of this species is treeholes and artificial containers (e.g., discarded tires). The overwintering life stage is reported to be egg or larva. Host preference is avian, with adult females are rarely collected in CO2–baited CDC light traps. It is a multivoltine species.
- Psorophora ciliata — The overwintering life stage of this species is the egg. Larval habitat is temporary grassy pools and roadside ditches in sunlit areas. Larvae are predaceous and cannibalistic. Host preference is for mammalian blood. Females are aggressive and persistent human biters that will attack anytime of the day or night. This species is not attracted to CDC CO2–light traps. No virus isolations have been reported out of Connecticut. It is a multivoltine species.
- Psorophora columbiae — Psorophora columbiae, formerly known as Ps. confinnis, is a widespread pest from Florida, where it is known as the "glades mosquito", to New York. Scattered populations exist in Massachusetts and across the United States westward to California. The species is found in Mexico, Central America, the Caribbean and South America to Argentina. Psorophora columbiae reaches its greatest abundance in the rice growing areas of the southwestern U.S. where astronomical numbers, similar in magnitude to the production of saltmarsh mosquitoes, may occur. Eggs are deposited on moist soil which is subject to flooding by water from rainfall or irrigation. The incubation period is about 3-5 days in the rice growing areas of Arkansas. The larvae mature rapidly during the hot summer, often developing from first instar to pupae in as few as 3.5 days. The larvae develop in temporary shallow freshwater pools and puddles where there is vegetation. The larvae may occasionally be found in slightly brackish water. Ideal sites for production of larvae are ricefields, grassy roadside ditches, and grassy swales. The normal flight range of this mosquito is at least 6-8 miles; however, much longer distances have been recorded. The mosquito is readily attracted to light, and the New Jersey light trap is commonly used to monitor populations. The females are furious biters in day or night. Hosts include any warm blooded animal; however bovine blood seems to be preferred.
- Psorophora ferox — This is a multivoltine species with preferred larval habitat in temporary woodland pools and depressions in shaded floodplains. Host preference is for mammals, and females are aggressive human biters that attack anytime of the day or night when disturbed in the vicinity of their wooded larval habitats. Virus isolates report from Connecticut are Cache Valley, Eastern Equine Encephalitis, Highlands J, Jamestown Canyon, Trivittatus and West Nile.
- Toxorhynchites rutilus septentrionalis — Predatory mosquitoes in the genus Toxorhynchites are the most common arthropods which have been used for control of "container-breeding" mosquitoes. The combination of carnivorous larvae and innocuous adults is very attractive in biological control. Successful biological control has been reported using Toxorhynchites species from Japan, Southeast Asia, the Caribbean and the United States. Most of the 71 species of Toxorhynchites are found in forested tropical regions throughout the world. At least one, Toxorhynchites rutilus, has a subspecies (septentrionalis) that is found as far north as 40 degrees N latitude in Connecticut and southern New York. Limited collections have been made in the CMMCP area in Millbury and Worcester. The other subspecies of Toxorhynchites rutilus found in mainland United States, Tr. rutilus, has been reported only from Florida, Georgia and Louisiana. Toxorhynchites are unusually large mosquitoes; the wingspan may exceed 12 mm; the body length may exceed 7 mm. Adults are frequently covered with iridescent scales and the proboscis has a pronounced 90 degree downward curve. Fourth instar larvae may be more than 2 cm in length. Adults feed on plant nectars. A few species are precocious and do not need nectar to initiate oviposition. Protein used in reproduction is apparently entirely derived from larval feeding, although some nectars may provide modest amounts of some amino acids. Cumbersome in flight, they are most frequently seen resting near treeholes or engaging in their characteristic elliptical oviposition flight patterns at the mouth of natural and man-made containers. They are not known to oviposit in small ponds or other open water such as ground pools. Larvae feed on the living macroinvertebrates inhabiting flooded treeholes, bromeliads and man-made containers. They are dependent on movement for prey location. Although they are more successful in feeding on mosquitoes, eating as many as 400 larvae during their larval development periods, they can successfully complete larval development with artificial protein sources such as water fleas (Daphnia) or brine shrimp. Cannibalism is not uncommon, especially in small containers, but containers such as tires with ample food supplies may support half a dozen or more similarly sized larvae. Larval behavior is especially intriguing with feeding dependent on prey size and availability. Wanton killing of prey without feeding has been reported. All known species are multivoltine. In the United States, Toxorhynchites generally overwinter as late larval instars. Diapause is controlled by day length, rather than temperature. Although the use of Toxorhynchites alone is unlikely to reduce pest or vector species below operational thresholds, they can be a valuable tool in areas where containers and treeholes contribute substantially to the standing crop of mosquitoes. However, they are highly susceptible to insecticides, and care has to be exercised in the timing of release of Toxorhynchites and application of insecticide sprays. Their large size and docile appearance create the opportunity for them to serve as focal points for public awareness campaigns aimed at the cleanup of man-made containers that are used as breeding sites by pest mosquitoes.
- Uranotaenia sapphirina — Uranotaenia sapphirina is found from southeastern Canada to Florida along the eastern seaboard of the United States. Its range extends into the central states west to North Dakota and south into Mexico. Uranotaenia sapphirina has a life cycle that is similar to many of the Culex species. The adult females enter hibernation after they have been inseminated in the fall, pass the winter in a state of torpor and emerge in late spring to initiate a multivoltine breeding season. The species lays unique egg rafts that float partially submerged on the water's surface. Larvae are rarely evident until July, but peak sharply during the month of August. Larvae persist in prime breeding habitat into the month of September but decline sharply with the onset of cool weather. The brightly ornamented adults do not fly far from their breeding site but are readily attracted to artificial light. Light traps that are placed near suitable breeding habitat frequently give an overestimation of this species' population density during the summer months. Uranotaenia sapphirina is a mosquito that is almost always associated with permanent and semipermanent ponds that support rich stands of emergent and floating vegetation. In many areas of Massachusetts, Duckweed (Lemna sp.) appears to be an indicator plant. The larvae often congregate in large numbers among the tiny leaves and trailing roots of this floating aquatic plant. Water depth can vary from a few inches to several feet in the swampland utilized by this species. Uranotaenia sapphirina larvae usually avoid shade and are usually found in greatest abundance in sunlit areas of the breeding habitat.
- Wyeomyis smithii — Wyeomyia smithii belongs to the tribe Sabethini, a group of 12 mosquito genera that share more biological than taxonomic characteristics. The tribe is well represented in the New World tropics. Wyeomyia is the only sabethinegenus that occurs in North America. Wyeomyia smithii has a distribution that extends from Newfoundland south to Delaware, west to northern Illinois and northwest into Saskatchewan. The mosquito's distribution corresponds to the range of the northern pitcher plant, Sarracenia purpurea gibbosa. Another pitcher plant mosquito, Wyeomyia haynei, is found in the southern pitcher plant, Sarracenia purpurea venosa, from Maryland to South Carolina. The range of the two pitcher plant mosquitoes does not appear to overlap. Wyeomyia smithii is a multivoltine mosquito that completes its entire life cycle in the immediate vicinity of its predacious host plant. The females deposit their eggs directly on the water within the plant or just above the waterline in older leaves. The larvae live in the liquid of the plant and feed on the carcasses of insects and spiders being digested by the plant enzymes. Multiple generations take place from spring through fall. Late in the season, the females attach eggs to young leaves, before they become filled with water. The species overwinters as a larva frozen in a block of ice within the plant. The overwintering larvae pupate during the month of May and are usually on the wing by June. Wyeomyia smithii is an obligate inhabitant of the predacious pitcher plant and has never been reported from any other larval habitat.
Credit must be given for the information complied here to Dave Henley at the East Middlesex Mosquito Control Project, Dr. Wayne Crans at Rutgers University (retired), Tim Deschamps and Curtis Best at the Central Massachusetts Mosquito Control Project, as well as the Massachusetts Entomologist group.
Special thanks go to Ted Andreadis and his staff at the Connecticut Agricultural Experiment Station for the excellent publication “Identification Guide to the Mosquitoes of Connecticut”.