Biology, Surveillance and Control of Mosquito Vectors

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a) Anopheles spp

b) Aedes albopictus

c) Culex spp

Figure 4.2: Eggs of a) Anopheles, b) Aedes, and c) Culex mosquitos.

conditions, these eggs may hatch the next time they are flooded, as soon as ten days, or

may not hatch until they are flooded one year or later (Harbach & Knight 1980, Jorge

2001).

4.3.2

Larval stage of mosquitos

The larvae (wigglers or wrigglers) of all mosquitos live in water and have four de-

velopmental periods or instars. These are called 1st, 2nd, 3rd, and 4th instars with each

succeeding stage larger than the last. At the end of each instar, the larva sheds its skin by a

process called molting. The larva is an active feeding stage. Larvae feed on particulate or-

ganic material in the water (Figure 4.3 and 4.4). The larvae of most species have breathing

and must occasionally come to the surface of the water to get oxygen. The total length of

time that larvae spend in the larval stage depends on the species and the water temperature.

Some can develop in as little as 5 or 6 days. Upon maturity the 4th instar larvae molts into

the pupal stage (fmel.ifas.ufl.edu/key/anatomy/larval.shtml, Harbach

& Knight 1980, Jorge 2001).

4.3.3

Pupal stage of mosquitos

Unlike most other insects, the mosquito pupa is very active, and, like the larva, lives

in water. It differs greatly from the larva in shape and appearance. The pupa has a