Some eggs require a drying period, remaining dormant for months, they hatch soon after water contacts them. Many species breathe air through an elongated air tube which they extend through the water surface. Larvae change into comma-shaped pupae, often called tumblers, in about a week. The pupae transform into adults in about two days. Male mosquitoes feed on nectar of flowers and do not bite.
Mosquitoes show considerable variation in their preferred hosts.
Some species feed on cattle, horses, or other domestic animals while others prefer man. A few species feed only on cold-blooded animals and some live entirely on nectar or plant juices. Some are active at night and others only during the daytime. The primary vectors of St. Louis encephalitis virus are mosquitoes in the subgenus Culex . We have developed an identification system using ribosomal DNA for species identification.