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You can sometimes see them at the surface of water -- they are small and their bodies move in a S-shaped motion. The larvae go through four growth stages called "instars" before they molt into the pupa stage. The pupal stage lasts to two to three days. Then, a week after the eggs hatched, adult mosquitoes emerge from the water.
Two days after emerging, female mosquitoes are ready to track you down and suck some blood so they can go make more mosquitoes. The male mosquitoes just hang out and eat flower nectar or plant juices. Most mosquitoes stay close to where they were hatched so they can raise another brood.
Some mosquito species only have one generation each year. Others can have four or more! In the winter, most mosquitoes survive as eggs in the soil. These eggs are in a dormant stage called "diapause" which prevents them from hatching if it floods. They'll only hatch out of the diapause stage when the day length gets longer. Some adult females and also some large pupae can survive the winter also in a diapause stage if they can find a protected spot.
Because mosquitoes pierce your skin with their needle-like mouths and leave some of their saliva in your body when they bite you, they can also leave behind some nasty diseases. In some areas of the world, these diseases kill thousands of people each year. Some of the more common diseases transmitted to people mostly in tropical climates by mosquitoes include:. In Minnesota, mosquitoes can transmit encephalitis to people. To reduce your chance of getting this disease, do the following:.
The United States has worked very hard to reduce the risk of mosquito-born diseases through its mosquito control programs. Therefore, many of these diseases are rare in the this country. However, incidences of mosquito-born diseases has seen an increase in recent years. Early European explorers to North America referred to the huge numbers of bugs that hatch in the spring -- especially mosquitoes -- as the "scourge of the north.
Mark Twain wrote that, "two could whip a dog and four could hold down a man. So with all their bad characteristics, do mosquitoes have any good qualities? Why, yes! Louis, LaCrosse, Eastern equine and Western equine. These viruses are normally infections of birds or small mammals. During such infections, the level of the virus may increase in these infected animals facilitating transmission to humans by mosquitoes. The West Nile virus, which can also cause encephalitis, was found in the northeastern United States for the first time in , is a good example of this mode of transmission.
Human cases of encephalitis range from mild to very severe illnesses that, in a few cases, can be fatal. Dengue is a viral disease transmitted from person to person by mosquitoes.
It is usually an acute, nonfatal disease, characterized by sudden onset of fever, headache, backache, joint pains, nausea, and vomiting. While most infections result in a mild illness, some may cause the severe forms of the disease. Dengue hemorrhagic fever, for example, is characterized by severe rash, nosebleeds, gastrointestinal bleeding and circulatory failure resulting in dengue shock syndrome and even death. Dengue is endemic in the Caribbean, Central and South America. Recently, dengue has occurred with increasing frequency in Texas.
Other pathogens transmitted by mosquitoes include a protozoan parasite which causes malaria, and Dirofilaria immitis , a parasitic roundworm and the causative agent of dog heartworm. Disease carrying mosquito species are found throughout the U. The life cycle of all mosquitoes consists of four distinct life stages: egg, larva, pupa and adult.
The female mosquito lays the eggs directly on water or on moist substrates that may be flooded with water. The egg later hatches into the larva, the elongated aquatic stage most commonly observed as it swims in the water. The larva transforms into the pupa where internal changes occur and the adult mosquito takes form.
After two days to a week in the pupal stage, the adult mosquito emerges onto the water's surface and flies away. Only the female mosquito takes blood which they usually require for her eggs to develop. The practice of mosquito control focuses on the unique biology and behavior of the mosquito species of concern. Mosquito biology can follow two general scenarios.
The first involves those species that lay their eggs in masses or rafts on the water's surface. Some of these species, which are found throughout the U. The second scenario involves mosquitoes that lay their eggs on moist soil or other substrates in areas that will be flooded with water later. After about two days, these eggs are ready to hatch, but if not flooded, can withstand drying for months.
In inland areas of the U. Similar situations occur along coastal areas with mosquitoes adapted to salt marsh habitats. Some salt marsh mosquitoes are strong fliers and can sometimes travel up to 50 miles from the breeding site. In response to these potential disease carrying pests, communities organized the earliest mosquito control programs in the eastern U.
Eventually, other communities created similar programs throughout the country in areas where mosquito problems occurred and where citizens demanded action by local officials.
Modern mosquito control programs in the U. Surveillance methods include studying habitats by air, aerial photographs, and topographic maps, and evaluating larval populations. Mosquito control officials also monitor mosquito traps, biting counts, and complaints and reports from the public. Mosquito control activities are initiated once established mosquito threshold populations are exceeded. Seasonal records are kept in concurrence with weather data to predict mosquito larval occurrence and adult flights.
Some mosquito control programs conduct surveillance for diseases harbored by birds, including crows, other wild birds, sentinel chicken flocks, and for these diseases in mosquitoes.
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