
There are over 2500 different species of mosquitoes throughout the world of which 150 species occur in the United States. 52 species occur in California,
and 19 species occur in Alameda County. In the course of the District's operation about 10 species are commonly found in the County. Eight of the species
account for over 99% of complaints from the public.
Each of the species has a scientific name that is Latin, such as Culex tarsalis. These names are used in a descriptive manner so that the name tells something
about this particular mosquito. Some species have what is called "common names" as well as scientific names, such as Anopheles freeborni, the "Western malaria mosquito".
All mosquitoes must have water in which to complete their life cycle. This water can range in quality from melted snow water to sewage effluent and it can be in any container imaginable.
The type of water in which the mosquito larvae is found can be an aid to the identification of which species it may be. Also, the adult mosquitoes show a very distinct preference for the
types of sources in which to lay their eggs. They lay their eggs in such places such as tree holes that periodically hold water, tide water pools in salt marshes, sewage effluent ponds,
irrigated pastures, rain water ponds, etc. Each species therefore has unique environmental requirements for the maintenance of its life cycle. Learn some ways to treat the breeding site if source reduction doesn't work.
The feeding habits of mosquitoes are quite unique in that it is only the adult females that bite man and other animals. The male mosquitoes feed only on plant juices. Some female
mosquitoes prefer to feed on only one type of animal or they can feed on a variety of animals. Female mosquitoes feed on man, domesticated animals, such as cattle, horses, goats, etc;
all types of birds including chickens; all types of wild animals including deer, rabbits; and they also feed on snakes, lizards, frogs, and toads.
| Eggs Laid on water or ground until flooding |
Larva Initially very small but grow rapidly to 1/4 inch |
Pupa Looks like a small seed resting in the water |
Adult The female is the one that does the biting |
Eggs Laid on water or on the ground where they remain until flooding occurs. Shortly after they are in water, the eggs will hatch into larvae.
Larva Initially very small but rapidly grows to a size of 1/4 inch or longer. The larger ones are easily seen wiggling in the water or resting at the surface, breathing through their air tubes. They will dive at the least disturbance of the water, even if a shadow is cast over them.
Pupa Looks like a small seed resting in the water, but it will dive and move about rapidly with a jerking motion when disturbed. When fully developed, the adult will emerge from the pupal case ready to start the next generation. If the water dries up before the adult emerges, the mosquito will die.
Adult The female is the biting insect everyone is familiar with. She generally requires a blood meal before laying eggs that will hatch. She can fly several miles, if necessary, to get it. Her life-span may be 3 weeks to several months, during which time she will lay up to 500 eggs in batches of 50 - 100.