Only female mosquitoes bite humans.

Mosquitoes belong to the family Culicidae, and their feeding habits differ significantly between sexes. Both male and female mosquitoes primarily consume plant nectar and sugar juices to maintain their daily energy levels. However, the female mosquito possesses specialized mouthparts called a proboscis, which is designed to pierce skin and extract blood.This blood meal is not for the female's own nutrition but is a biological necessity for vitellogenesis, the process of yolk formation. Blood contains high concentrations of proteins, amino acids, and iron that are absent in nectar. Without these specific nutrients, the female's ovaries cannot produce viable eggs. Researchers at institutions like Johns Hopkins University have identified specific odorant receptors that help females track human carbon dioxide emissions and heat.After a successful feeding, the female mosquito rests for two to three days to digest the blood and develop her eggs. A single female can lay between 100 and 300 eggs at a time, often repeating this cycle several times during her lifespan. This reproductive requirement is why mosquitoes are primary vectors for diseases like malaria, dengue fever, and the Zika virus. Because males do not produce eggs, they never seek out hosts or transmit these blood-borne pathogens.