Mosquitoes need water to breed since all mosquitoes spend their larval and pupal stages in water. Therefore, mosquitoes can always be found around water. This is why it is important to prevent stagnant water from standing around your home and apply a larvicide to areas where stagnant water cannot be removed. The incubation time between egg and adult is about 10 days in warmer weather and is greater than one month in cooler weather. Culex pipiens, which carry West Nile virus breed from late May until the first frost.
Most adult mosquitoes wind up as food for birds, dragonflies, or spiders.
Others succumb to the effects of wind, rain, and drought. In Connecticut, some adult mosquitoes become inactive with the onset of cold weather and enter into hibernation before the first frost. Other mosquitoes die in the fall but have winter-hardy eggs, which hibernate as embryos. Only in the last century has it been known that mosquitoes are capable of spreading disease. The diseases are often viruses that are picked up by the mosquito when it feeds on an infected host.