Although you probably associate mosquitoes with warm climates, 32 species have been recorded in Britain. These include species that transmit diseases elsewhere in the world. Although you may not consider them to be garden insects, there is a high chance that some species are breeding in water-filled containers in you garden from May onwards. They will happily live in water butts and any other reasonable sized container that has standing water; they have even been known to lay eggs in water dishes put out for pets. Mosquitoes lay their eggs in still water and begin life as aquatic larvae and pupae breathing oxygen from the surface. Adults emerge from the pupal stage and most female mosquitoes need to feed on blood to produce eggs. Most British species will bite humans, but they usually feed on frogs, birds, mammals and reptiles. The male mosquito only feeds on nectar and honeydew.
The biggest mosquito is Toxorhynchites, with a wingspan of up to 2.5cm. It doesn't bite and the larvae eat larvae of other mosquito species.
Larvae of the mosquito Coquillettidia richiardii breathe oxygen by penetrating the vascular system of submerged aquatic plants.
Adult mosquitoes of the human-biting form of Culex pipiens are spreading worldwide from Africa by stowing away on airplanes. They have been caught on planes landing at Heathrow. Larvae also travel across oceans on boats transporting old tyres filled with water.