Biology, Surveillance and Control of Mosquito Vectors

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mosquito are high and can bite human actively. Repellents are very good option in the

strategy of mosquito control, they do not kill them, but just repel and prevent them to land

in bare body parts.

The process of the impregnation of extracted repellent chemical substances by different

plants like Citronella etc., is complicated and should have been taken by very professions

chemists or chemical engineers. Knowing these important data of mosquitos, their control

can be more successful. Except optimal temperature and of many pond, pool or dams;

humidity is one of the most important ecological factors for the survival of the mosquitos.

It is not just the humidity of the air that cause this successful life of mosquitos, but the

humidity conserved in the low grassy vegetation, tree holes, tree dense vegetation leafs,

which can really be very good places where humidity can be sufficient for their growth in

recreational parks near by the jungles, forests or even in the yards with dense vegetation

and flower pots.

4.2

BIOLOGY OF MOSQUITOS (CULICIDAE)

Mosquitos belonging to the phylum Arthropoda, class Insecta, subclass Pterygota, or-

der Diptera and the suborder Nematocera. There are some 3500 species of mosquitos be-

longing to 41 genera, all contained in the family Culicidae of which about 100 are vectors

of human diseases. Control measures are generally directed against only one or a few of

the most important species and can be aimed at the adults or the larvae. Culicidae family

is divided into three subfamilies: Toxorhynchitinae, Anophelinae and Culicinae (Service

1993ab; Harbach & Kitching 1998).

Mosquitos have a worldwide distribution (Knight and Stone 1977). They occur

throughout the tropical and temperate regions and extend their range northwards into the

Arctic Circle. The only area from which they are absent is Antarctica, and a few islands in

pacific. They are found at elevations of 5500m and down mines at depths of 1250 m below

sea level (Harbach & Knight 1980, 1998). Mosquitos are important vectors of several trop-

ical diseases, including malaria, filariasis, and numerous viral diseases, such as dengue,

Japanese encephalitis, Chikungunya, Zika and yellow fever. In countries with a temperate

climate, they are more important as nuisance pests rather than as vectors (Service 1993,

Harbach & Kitching 1998).

4.3

LIFE STAGES OF MOSQUITOS

The mosquito has four distinct stages: eggs, larvae, pupa, and adults (Figure 4.1). For

more information please have a look at the given reference (Ferguson College website).

The adult is an active flying insect, while the larvae and pupae are aquatic and occur

only in water. Depending on the species, eggs are laid either on the surface of water or are

deposited on moist soil or other objects that will often be flooded (Service 1993). There are

4 instars of larvae, in each of them a molting event occur, where the growth of the larvae

body is associated with the molting event. Depending on the species, a female lay between

30 and 300 eggs at a time. Many species lay their eggs directly on the surface of water,