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Mosquito Life Cycle

Mosquitoes belong to one of the largest insect orders, the Diptera (true flies). Within this order are 67 families, mosquitoes belong to the Culicidae family. There are four genera that are of particular interest within British Columbia and Yukon due to their disposition to bite humans and animals. These include Aedes, Anopheles, Culex and Culiseta.

 

Mosquitoes go through four distinct stages of development during their life: egg, larvae, pupa and adult. Eggs of some species can remain dormant for upwards of 25 years before hatching. Larvae hatch in ponds, catch basins, puddles and other stagnant bodies of water during spring and summer. At this stage of their lifecycle, larvae go through four phases of growth (1st instar to the fully grown 4th instar) moulting their skins as they grow. After a voracious feeding on plant material the larvae quickly develop into pupae from which the adult emerges at the surface of the water. The females then go in search of a blood meal to complete egg development.

Mosquito Larvae

Species of Aedes are abundant from mid May to early August. Their numbers slowly drop as they die off in the fall, after laying their eggs. Eggs are laid in ground crevices and low growing vegetation in areas that are flooded in the spring such as river flood plains and water-holding containers. Larvae must develop in water! They do not hatch and grow in fields of long moist grass. The eggs of some Aedes species will only hatch after a period of drying and chilling, while some eggs only produce larvae after the second or third summer. The first larvae of Aedes can usually be found in late March to mid April. Most Aedes species produce only one generation a year, but late hatching larvae can be found until late June or early July.

 

Females of Anopheles, Culex and most species of Culiseta hibernate between November and March. Some of the Culiseta are known as snow mosquitoes because the females often emerge from hibernation on warm days when snow is still on the ground. Mosquitoes that hibernate do not bite since they took their blood meal prior to hibernation. These mosquitoes usually die a few weeks after they emerge and lay their eggs.


The eggs of Anopheles, Culex and Culiseta are laid on the surface of water. Anopheles lay their eggs singly, Culex and Culiseta lay their eggs in rafts. These eggs hatch within a few days. Larvae usually appear in early April. Eggs, larvae and pupae can be found throughout the summer because most species of these genera can produce several generations in one season.