Numerous information sources discuss mosquito biology, mosquito-borne diseases, methods of personal protection, and approaches to mosquito control. Still, many people lack understanding of the biology and public health importance of mosquitoes. The mosquitoes that carry West Nile virus typically lay their eggs in stagnant water and water-holding containers. Weeds, tall grass, and shrubbery provide an outdoor harborage for adult mosquitoes. You can reduce the number of mosquitoes around your home and neighborhood by eliminating places where they lay their eggs. Mosquito-borne diseases are a major health hazard worldwide. Some, like malaria, chronically afflict certain regions. Mosquitoes can be very annoying, their bites can produce itchy welts, and the bites of some species are painful to certain individuals. "Quality of life" can be reduced in areas with high numbers of biting mosquitoes. Mosquitoes also are vectors (transmitters) of several viruses that can cause severe diseases.
Mosquitoes develop from egg to adult via a process of complete metamorphosis. This means they have a pupal stage in which the aquatic larva transforms into a flying terrestrial adult. All species of mosquitoes have four life cycle components: an egg stage; four larval stages; a non-feeding pupal stage; and an adult stage. Mosquito eggs are laid either singly or together in a raft-like structure that floats on water, and they hatch via one of two mechanisms. Awareness of the differences between these two mechanisms is essential to understanding the diversity of mosquito life cycles and to practicing the most effective approaches to mosquito control.