Eggs are laid in water, and for some species, even a water-filled footstep will suffice for egg and larval development. There are two subfamilies of mosquitoes, Anophelinae and Culicinae, which differ in egg morphology and disposition, larval position in relation to water surface and the resting position of the adult. Aedes can transmit the filarial nematodes Brugia spp . Remember, its just the blood-feeding female mosquito that transmits disease, the male requires only sugar for survival. Certain species of blackflies of the genus Simulium are responsible for transmission of the filarial nematode, Onchocerca volvulus , the causative agent of 'river blindness' in central and western Africa.
Species can also transmit various forms of cattle onchocerciases.
Flies live in the vicinity of streams in woodland and eggs are laid close to or in well-aerated running water. They are daytime biters attacking mammals and birds. The flies have a dark humped thorax and it is only the female that feeds on blood, but she can also supplement her diet by feeding on plant sugars. Transmission occurs through the mouthparts which are designed to pierce the skin. Sandflies are pale brown flies that move in a series of flying 'hops'.