Not all mosquitoes bite... Only female mosquitoes require a blood meal. The proteins in blood allow for development of her eggs, which she lays in rafts on the surface of calm water or moist edges. Males never take a blood meal; they feed only on nectar. Females also feed on nectar for their energy needs.
Females can detect carbon dioxide from more than a football field away. They zero in on it to find the source: a host. Female mosquitoes may vector diseases, including West Nile virus, malaria, etc. They may contract the virus or organism during the host of a first feeding, then transmit it during a later feeding to another host. The best ways to avoid mosquito bites include lightweight, long-sleeved shirts, pants, tight-fitting screens on windows and patio doors, citronella candles, and insect repellents. Electronic pulsing devices have never proven effective in repelling mosquitoes.