Mosquitoes have been around for many years, since prehistoric times, perhaps four million years or more. Some mosquitoes have been found embedded in amber from the late Cretaceous and Jurassic periods, some with the blood meal still intact.
Throughout history more individuals have died from mosquito-borne diseases than from any other single cause of mortality, including wars and famine. Even now, malaria continues to be the leading cause of mortality in many third world countries, causing over two million deaths among 270 million new cases annually.
There are approximately 3,500 species of mosquitoes distributed worldwide. Most, but not all, are capable of feeding upon humans and domestic animals, although they may not always prefer to do so. Many feed upon birds, wild animals or reptiles. In any one locality, relatively few species occur in numbers sufficient enough to create problems.
Life Cycle of a Mosquito
Mosquitoes have four different stages of their life cycle - egg, larva, pupa, and adult. During each stage of their life cycle, the mosquito looks distinctly different than any other life stage. The mosquito egg can develop into an adult mosquito within one week.
The most common mosquitoes lay eggs rafts that float on the water. Each raft contains from 100 to 400 eggs. Within a few days the eggs hatch into larva.
The larva "wiggler" comes to the surface to breathe through a tube called a siphon. It sheds its skin or molts four times during the next several days, It grows rapidly between each molt. On the fourth molt it changes in to a pupa.
The pupa or "tumbler" cannot eat. It breathes through two tubes on it back. The adult mosquito grows inside the pupa and in two days or so, when it is fully developed, it splits the pupal skin and emerges to complete the life cycle or metamorphosis of the mosquito.
The newly emerged adult rests on the surface of the water until it is strong enough to fly away and feed.