Where Mosquitoes Breed and How They Live Their Life Cycle

As part of our public awareness campaign during this week’s observation of Guam Mosquito Control Awareness Week, the Division of Environmental Health of the Department of Public Health and Social Services wishes to provide information on today’s topic: Where mosquitoes breed and how they live their life cycle.

Mosquitoes carry diseases, including West Nile virus, Dengue Fever, malaria, Eastern equine encephalitis virus, and heartworms.  Guam has been very fortunate that all reported human cases of mosquito-borne diseases on island in the past decades were acquired off-island.  However, to prevent the introduction and spread of these diseases, we all must do our part.  The public has to be an integral part of our fight against mosquito-borne diseases.

All mosquitoes go through a life cycle of four stages: egg, larva, pupa, and adult.  The cycle begins when a female mosquito obtains a blood meal by biting an unsuspecting victim.  One blood meal supplies sufficient nutrients for the female mosquito to lay up to two hundred and fifty eggs at one time.  After the meal, she finds an aquatic location to lay her eggs, which is usually directly on the surface of stagnant water, in a depression in the sand along water, or on the edge of a container where water may collect.  In as little as 48 hours, the eggs hatch into larvae, which appear as worm-like creatures.  A larva lives in the water from 7 to 14 days, feeding on microorganisms, and comes to the surface only to breathe.  It then becomes a pupa and stops feeding.  After 1 to 4 days in this stage, a fully developed adult mosquito with wings emerges from the pupa shell and rests on the surface of the water until it is ready to fly away to find a blood meal if it is a female.  Male mosquitoes do not need to feed on blood; instead, most feed on plant nectar.

The mosquito larvae cannot live and become adult mosquitos without water.  Thus, we must eliminate standing water in our community whenever possible.  So containers that can hold water around homes, schools, and businesses must be removed, emptied regularly, or turned over.  Also, fill in low-lying areas that can collect water and become a breeding site.

One of the simplest ways to get rid of mosquitoes is to interrupt their life cycle by eliminating their breeding sites.  So let us all “fight the bite” of mosquitoes by removing standing water that can allow mosquitoes to live and grow.

For more information please contact the Mosquito Surveillance and Control Program of the Division of Environmental Health of this Department at 735-7221.

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