Female mosquitoes bite us for the nutrients in our blood. These nutrients are necessary for the development of eggs, which is why male mosquitoes do not bite or feed on blood. After a female mosquito bites, she is able to breed and lay eggs.
While we call it “biting”, in reality, the female mosquito is piercing your skin with her proboscis, almost like a needle. The proboscis contains two tubes. One injects saliva that contains a mix of chemicals to numb pain, thin your blood, and prevent it from clotting. The other tube sucks up the blood.