Mosquito Biology

Mosquitoes belong to the insect order Diptera, and the family Culcidae. They have been deemed biting flies for they must draw blood from other animals in order to facilitate reproduction.

There are more than 2600 species, which are grouped together into 31 or more genuses. There are 74 different species found in Canada, 64 or which are known to bite humans and/or domestic animals. The Southeast Regional Service Commission publishes a species profile for the Greater Moncton area.

Mosquitoes have developed to lay their eggs in a variety of environments with each genus favouring a particular set of conditions. The Aedes genus lay theirs eggs singly just above the water line so that they dry out. The eggs will wait in a dormant stage until water levels rise due to flooding conditions. Once the eggs come in contact with the water the eggs will hatch.

The Culex genus lay their eggs in rafts directly on the surface of the water. Each raft may contain 100-400 eggs each cemented side to side. Culex can take advantage of almost any water container, natural or artificial. Culex can over winter as adults by hibernating in cool damp locations.

Larvae hatch from these eggs and filter feed on decaying organic matter. Larvae are very active in their aquatic environment and have been called “wrigglers” due to their constant movement. Larvae move by thrashing their abdomen back and forth to propel themselves up and down through the water column. The larvae are equipped with a siphon to breath air at the water surface.

During the course of a few days to a few months, the larvae develop through four stages (instars). The last stage leads to the Pupa stage. The rate of larvae development is heavily dependant on the water temperature.

Pupae are less mobile than larvae and do not feed. It is during this stage that the metamorphosis to an adult takes place.

After several days, the adult emerges from the pupal casing and immediately rests at the water’s surface for a few days in order to harden its outer skin.

Mosquitoes will mate over a two to three day period and females will start seeking a blood meal within a week. After securing this source of protein (blood meal), the female will find a cool resting place where she can convert the blood meal into eggs. Both male and female mosquitoes feed on flower nectar as a personal food source. A mosquito’s life span can vary from one week for the males, to several months for the females, depending on environmental conditions.

Mosquitoes & Disease

Mosquitoes are defined as vectors due to their disease transmission capabilities. Vectors transmit disease by biting an infected host and then biting an uninfected target. Often the host is not affected by the disease but rather acts as a reservoir for the disease pathogens. The pathogens need to be highly concentrated in the host’s blood in order for the mosquito to transmit the disease.

Pathogens are not spread by blood-to-blood contact but rather from the salivary glands of the mosquito. Because of the physiological process required in the body of the mosquito for the pathogen to penetrate the salivary glands, not all diseases can be contracted by a mosquito bite. It is noteworthy that the AIDS virus cannot be transmitted by a mosquito bite. Since some mosquitoes only bite birds, disease can be concentrated within the bird population. Monitoring bird populations can therefore be a good indicator to potential health threats.


Mosquito Breeding Habitats

The following are typical breeding habitats for mosquitoes:

  • Salt Marshes
  • Roadside Ditches
  • Catch Basins
  • Hardwood & Coniferous
  • Freshwater Swamps
  • Freshwater Marshes & Ponds
  • Temporary Woodland Pools
  • Fresh Floodwater
  • Tree Holes
  • Artificial Containers