Life Cycle

Once adult mosquitoes mate, the female mosquito requires a blood meal to produce eggs. She will search for a suitable aquatic habitat to lay her eggs, either singly or as a cluster known as an egg raft, seen in the photos below.

Once developed, mosquito larvae hatch from their egg cases. They will feed and molt through four stages called instars, increasing in size after each molt. Most species of mosquito larvae need to breathe air through a siphon tube on the tail end, and are often found hanging upside-down at the water surface.

After completing the fourth larval stage, the mosquito enters the pupal stage, which is similar to a caterpillar in a cocoon. In this stage, the mosquito does not feed and puts all of its energy into reorganizing its body structure from the larval form into an adult. All of this takes place inside of a pupal shell, pictured below. It still needs to breathe and remains at the surface of the water, moving only to escape predators. The pupal stage breathes through “air trumpets” which are located near its head.

After completing its metamorphoses, the adult mosquito will emerge from its pupal casing at the water surface. Using the water’s surface tension, the adult mosquito will rest until its exoskeleton hardens and it is able fly away. Both male and female mosquitoes require energy in the form of plant nectar. Males will search for female mates, the females will seek a blood meal, and the life cycle will continue.

Mosquito Virus Cycle

Usually, viruses such as West Nile virus and Eastern Equine Encephalitis virus cycle between the mosquito vector and its host, be it bird, mammal, or reptile. The virus needs a competent vector and a healthy host in order to complete and continue its life cycle. In the case of these particular mosquito-borne viruses, humans, horses, some bird species, and other animals fall ill when infected because we have not evolved to contain and pass on the virus, making us a “dead-end host.” We can become infected but cannot be infective; the virus cannot be picked up from us by another mosquito to continue its cycle.

For more information about mosquito surveillance, insect biology, pesticides, and related topics, please contact our entomologist through the form at the bottom of our surveillance page.