2. London's mosquitoes
Members of the same species can sometimes diverge into separate ones when isolated in diverse climates. Often vast oceans create these barriers – or, less
often, a city transport system. The London Underground mosquito spends its days in the subway system and has adapted to feed on the public as they hop on and off trains. Unlike their closest relatives above ground, which mainly feed on birds, the underground mosquito has been separated in the system so long it has become its own distinct species, feeding only on commuters.