FOSSIL AND EVOLUTION OF MOSQUITOES

Fossil and Evolution of Mosquitoes

              It is interesting to know that how mosquitoes are evolved. The oldest mosquito with an anatomy similar to modern mosquito was found in 79 million year ago in an Canadian amber from the Cretaceous. An older species with more primitive features was found in Burmese amber that is 90 to 100 million years old. Earlier than Cretaceous period there were no fossils found, recent studies suggests the the earliest divergence of mosquitoes between the lineages leading to Anophelinae and Culicinae occurred 226 million years ago.

               The mosquito Anopheles gambiae is currently undergoing speciation into the M(opti) and S(avanah) molecular forms. Consequently the pesticides works on M form no longer works on S form. The family Culicidae includes over 3,500 apecies which are described. They are generally divided into two subfamilies which in turn comprise some 43 genera. These figures are subject to continual change, as more species are discovered, and as DNA studies compel rearrangement of the taxonomy of the family. the two main subfamilies are the Anophelinae and Culicinae, with their genera as shown in the subsection below. The distinction is of great practical importance because the two subfamilies tend to differ in their significance as vectors of  different classes of diseases. Roughly speaking, arboviral diseases such as yellow fever and dengue fever tend to be transmitted by culicine species, not necessarily in the genus Culex. Some transmit various species of avian malaria, but it is not clear that they ever transmit any form of human malaria. Some species do however transmit various forms of filariasis, much as many Simuliidae do.