Mosquitoes go through four stages in their life-cycle: egg, larva, pupa and adult. Adult females lay their eggs in standing water, which can be a lake, a puddle, a natural reservoir on a plant, or an artificial water container such as a plastic bucket or bird bath. The first three stages are aquatic and last 5–14 days, depending on the species and the ambient temperature; eggs hatch to become larvae, then pupae. The adult mosquito emerges from the pupa as it floats at the water surface. Adults live for 4–8 weeks.
Mosquitoes have mouth parts that are adapted for piercing the skin of plants and animals. Female mosquitoes needs to obtain nutrients from a "blood meal" before she can produce eggs.
There are about 3,500 species of mosquitoes found throughout the world. In some species of mosquito, the females feed on humans, and are therefore vectors for a number of infectious diseases affecting millions of people per year.