In addition, many species can ingest pathogens while biting, and transmit them to future hosts. The mosquito's saliva is transferred to the host during the bite, and can cause an itchy rash. Thousands of mosquito species feed on the blood of various hosts - vertebrates, including mammals, birds, reptiles, amphibians, and some fish along with some invertebrates, primarily other arthropods. The adult females of most species have tube-like mouthparts (called a proboscis) that can pierce the skin of a host and feed on blood, which contains protein and iron needed to produce eggs. These larvae are important food sources for many freshwater animals, such as dragonfly nymphs, many fish, and some birds such as ducks. Eggs are laid on the water surface they hatch into motile larvae that feed on aquatic algae and organic material. The mosquito life cycle consists of egg, larva, pupa, and adult stages.
Mosquitoes have a slender segmented body, one pair of wings, one pair of halteres, three pairs of long hair-like legs, and elongated mouthparts. The word 'mosquito' (formed by mosca and diminutive -ito) is Spanish and Portuguese for 'little fly'. Mosquitoes are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin culex meaning ' gnat').
