Why mosquitos bite?
The primary reasone why mosquitos bite - is because the females need a blood meal to develop their eggs. Females need the protein to develop their eggs.
Harvard School of Public Health says: "Only female mosquitoes feed on blood. The blood triggers ovarian activity, and after a few days she lays several hundred eggs. A few weeks later, the eggs hatch. Two or three days later, they become full adult mosquitoes."
It is known, that some male mosquitoes have been known to suck blood, although they have no use for blood. These ones are called "Gynandromorphs"
The term "gynandromorph" literally means part female (gyn-) and part male (andro-).
Female mosquitoes of nearly all species require blood from vertebrate animals to develop eggs, and many species bite people, pets, and livestock for this purpose. The most important consequence of this is the transmission of icroorganisms that cause diseases such as western equine encephalomyelitis and St. Louis encephalitis. Both of these diseases can cause serious, sometimes fatal neurological ailments in people. (Western equine encephalomyelitis virus also causes disease in horses.) Western equine encephalomyelitis infections tend to be more serious in infants while St. Louis encephalitis can be a problem for older people. Some mosquitoes are capable of transmitting malaria to humans. If these mosquitoes suck the blood of a person that has malarial parasites, they may pass on the infection to the next person(s) they bite; however, malaria is currently rare in most parts of the world.