tiger-mosquito

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Asian tiger mosquito

The Asian tiger mosquito or forest day mosquito (Aedes albopictus), from the mosquito family Culicidae, is characterized by its black and white striped legs, and small black and white body. It is native to Southeast Asia, but nowadays is present on all continents excluding Antarctica and occurs as far north as 49° latitude in Germany.

Description and ecology

Other mosquitoes in North America, such as Ochlerotatus canadensis, have a similar leg pattern. The typical Aedes albopictus individual has a length of about 2 to 10mm. As with other members of the mosquito family, the female is equipped with an elongated proboscis that she uses to collect blood to feed her eggs. The Asian tiger mosquito has a rapid bite that allows it to escape most attempts by people to swat it. By contrast the male member of the species primarily feeds on nectar.

The female lays her eggs near water; not directly into it as other mosquitoes do, but typically near a stagnant pool. However, any open container containing water will suffice for larvae development, even with less than an ounce of water in. It can also breed in running water, so stagnant pools of water are not its only breeding sites. It has a short flight range (less than 200 m), so breeding sites are likely to be close to where this mosquito is found.

Disease vector

Aedes albopictus is a vector for dengue fever in parts of Asia. It is also a vector for chikungunya in Italy, Kerala.

Invasive species

This species is able to survive in a wide range of habitats and conditions, including cold mountainous areas. It is generally more aggressive than indigenous mosquitoes, and is outcompeting them.

Asian tiger mosquitoes were first found in North America in a shipment of used tires at the port of Houston in 1985. Since then they have spread across southern USA, and as far up the East Coast as Maine. This species is an introduced species in Hawaii as well, but has been there since before 1896.

They have been found in Italy since 1990, and in Nigeria since 1992. By mid-2007, the species was present in New Zealand, Eastern Canada, and 12 European countries including Italy and Spain where it may already be an established resident. In Switzerland the species was first found in 2003, in southern Ticino canton; in November 2007 a record from Aargau confirmed that it had crossed the Alps. In September 2007, the first Asian tiger mosquito eggs were found in Germany, near Rastatt. It was also recently confirmed to have established itself in Australia and Israel. It is one of the 100 world's worst invasive species according to the Global Invasive Species Database.

This mosquito has become a significant pest in many communities because it closely associates with humans (rather than living in wetlands), and typically flies and feeds in the daytime in addition to at dusk and dawn.

Control

Efforts to curb the spread of mosquito-borne illnesses have led many government agencies to initiate programs to spray for mosquito control. However, the Asian Tiger is not a known carrier of West Nile Virus in the United States. This mosquito is active in the daytime, not just after dawn and just before dusk as most indigenous mosquito species, and so is a likely culprit if people or pets are being bitten in the daytime. Most mosquito spraying done at night will have little effect on Asian tiger mosquitoes. (Daytime spraying may be a violation of label directions if foraging bees are present on blossoms in the application area.)

It is however, possible to find and deal with the breeding spots, which are never far from where people are being bitten, since this is a weak flyer, with only about a 200-yard lifetime flying radius. Locate puddles that last more than three days, sagging or plugged roof gutters, old tires holding water, litter, bird baths, kiddie pools, inlets to sewers and drainage systems holding stagnant water and any other possible containers or pools of standing water. Flowing water will not be a breeding spot and water that contains minnows is not usually a problem, because the fish eat the mosquito larvae. Dragonflies are also an excellent method of imposing control. Dragonfly larvae eat mosquito larvae in the water, and adults will snatch adult mosquitoes as they fly. Insecticide application that also kills dragonflies may actually cause only a brief suppression of mosquitoes, followed by a long term increase in populations.

Whenever possible, all sources of standing water, even if only a quarter cup, should be dumped every three days. Litter, especially containers in ditches, can hold water after the ditch dries up, and all litter should be cleaned up. Bird baths, wading pools, and any other containers that can hold rainwater should be emptied.

Any standing water in pools, catchment basins, etc, that cannot be drained, or dumped, can be periodically treated with properly labeled insecticides or Bacillus thuringiensis israelensis often formed into doughnut shaped "mosquito dunks." The BTI disease organism only affects pest insects. While floating or tied to a small weight, they slowly release a long term biological mosquito larvicide killing the larvae young mosquitos before they hatch into adults reportedly without affecting fish, plants, people or wildlife. It is readily available at farm, garden, and pool suppliers.

Footnotes

References

(2007): Epidemiology of tree-hole breeding mosquitoes in the tropical rainforest of Imo State, south-east Nigeria. Annals of Agricultural and Environmental Medicine 14(1): 31-38. PDF fulltext
(2007): Information on Aedes albopictus Version of 2005-NOV-07. Retrieved 2007-OCT-31.
(2007): Tropical Disease Follows Mosquitoes to Europe. Science 317(5844): 1485.
(2007): Mission Report - Chikungunya in Italy, 17-21.09.2007. PDF fulltext
(1993): What Bit Me? Identifying Hawaiʻi's Stinging and Biting Insects and Their Kin. University of Hawaiʻi Press, Honolulu.
(1992): The asian tiger mosquito, Aedes albopictus. Wing Beats 3(3): 5. HTML fulltext