There are over three thousand species of mosquitoes that have evolved over the last million years. Each of these species eat what is indigenous to their area; however all females, despite the species, seek out blood meals. Many of the different species of mosquitoes have adapted to climates from arctic weather to temperatures along the Equator. Interestingly enough, humans are not the host of choice in many temperate climates; however, they are still equal prey when given the opportunity. Some mosquitoes can seek out other species better due to their odor. Some species prefer herbivorous mammals, while others prefer birds. Typically, the species of mosquitoes that seek blood meals from birds are the ones carrying encephalitis or West Nile.
All adult mosquitoes, both male and female are nectar feeders that feed on flower nectar, juices, and decaying flowers alike. Other sources of food include organic particulates, decaying matter, frogs, mammals, and birds. The favorite food of females, however, is blood. Female mosquitoes are capable of hematophagy or drinking blood. The females do not require blood meals for their own survival, but rather for the development and later survival of their young. Blood meals provide the supplemental substances such as iron and protein that allows for egg development. After a blood meal, the female will reproduce sexually and then fertilization occurs. Although blood meals do not have anything to do with egg fertilization, fertilization only occurs after a blood meal is consumed.