Mosquitoes have been around for over 100 million years and have developed into more than 2500 species. All mosquitoes need water to complete their life cycle (egg-larva-pupa-adult) as the initial stage - eggs need to develop in a moisture environment which can be in a tree hole or sewage.

Adult female mosquitoes bite human and other animals to develop their eggs. On the other hand, the males feed only on plant juices or flower nectar.
The average life span of a male mosquito is 10 to 20 days while a female can live from 3 to 100 days.

For more information about mosquitoes, you can check the following sites:
www.mosquitoes.org/LifeCycle.html
www.control-mosquitoes.com/