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Taxonomy
Mosquitoes belong to the class of Insecta and the order Diptera (two-winged flies).
Mosquitoes belong to the suborder Nematocera, which includes many flies of economic importance as pests or disease vectors like midges, sand flies, black flies, mothflies, harlequin-flies. Most of the nematocerans are small, slender and long-legged, usually midge- or mosquito-like in appearance and can be recognised by their many segmented antennae, which are usually long.
The mosquito species most concerned with transmission of infections to humans and animals are contained in the genera Anopheles, Culex, Aedes, Ochlerotatus (formerly a subgenus of Aedes) and Mansonia, belonging to the subfamilies Anophelinae and Culicinae (with approximately 2000 species).
Classification of mosquitoes
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Diptera (i.e. two-winged insects) |
| Suborder: | Nematocera |
| Family: | Culicidae |
| Subfamily: | Anophelinae, Culicinae, Toxorhynchitinae |
| Genus: | e.g., Anopheles, Culex, Aedes and Mansonia |
Distribution
Mosquitoes are distributed widely throughout the world. They are found at altitudes of over ~4700 m, as well as in mines ~1250 m below sea level.
Species range in latitudes from the tropics northwards into the Arctic regions and southwards to the ends of the continents. A wingless species has been reported from Antarctica. Some oceanic islands appear to have been free from mosquitoes before the advent of man and modern travel and some still are. Besides a worldwide distribution they are in general predominantly tropical insects.
Epidemiology
Feeding habit, vector activity, including dispersion, and host activity or whereabouts of the host are defining the possibility of vector – host contact and thus the potential of disease transmission.
Anopheline adults mainly feed in the evenings and at night.
Regarding culicine feeding habits, adults of many Aedes and Ochlerotatus species bite during the day or early evening, while adults of many Culex and most Mansonia and Coquillettidia species bite at night. Most culicines feed and rest outdoors.
Concerning dispersion, mosquitoes usually travel only a few hundred meters from their emergence sites. While it is assumed that they generally do not fly further than 2 km, however dispersions of 100 km or more have been recorded, usually assisted by the wind. Artificial dispersion via railway aircraft and other transport also exists.
Apart from horizontal dispersion a definite vertical stratification in biting activity has been observed especially in many tropical forest mosquitoes. Some species bite mainly at ground level, while others are most active in the intermediate levels or in the forest canopy.
