The mosquitoes are a family of small, midge-like flies: the Culicidae. Although a few species are harmless or even useful to humanity, most are considered a nuisance because they consume blood from living vertebrates, including humans. The females of many species of mosquitoes are blood-eating pests. In feeding on blood, some of them transmit extremely harmful human and livestock diseases, such as malaria, yellow fever and filariasis
In the bloodsucking species, only the females suck blood. Over 3,500 species of mosquitoes have already been described from various parts of the world. Some mosquitoes that bite humans routinely act as vectors for a number of infectious diseases affecting millions of people per year
The first three stages—egg, larva, and pupa—are largely aquatic. These stages typically last five to 14 days, , but there are important exceptions. Mosquitoes Females of many common species can lay 100–200 eggs during the course of the adult phase of their lifecycles. Even with high egg and intergenerational mortality, over a period of several weeks, a single successful breeding pair can create a population of thousands.
Males typically live for about a week, feeding on nectar and other sources of sugar. A mosquito has a variety of ways of finding their prey, including chemical, visual, and heat sensors.
In many species, the female needs to obtain nutrients from a blood meal before she can produce eggs, whereas in many other species, she can produce more eggs after a blood meal. The feeding preferences of Mosquitos include those with type O blood, heavy breathers, those with a lot of skin bacteria, people with a lot of body heat, and the pregnant.
Both plant materials and blood are useful sources of energy in the form of sugars, and blood also supplies more concentrated nutrients, such as lipids, but the most important function of blood meals is to obtain proteins as materials for egg production.
A large part of the mosquito’s sense of smell, or olfactory system, is devoted to sniffing out blood sources. Of 72 types of odor receptors on its antennae, at least 27 are tuned to detect chemicals found in perspiration.
In Aedes, the search for a host takes place in two phases. First, the mosquito exhibits a nonspecific searching behavior until the perception of host stimulants, then it follows a targeted approach. Most mosquito species are crepuscular (dawn or dusk) feeders. During the heat of the day, most mosquitoes rest in a cool place and wait for the evenings, although they may still bite if disturbed. Some species, such as the Asian tiger mosquito, are known to fly and feed during daytime.
Prior to and during blood feeding, blood – sucking mosquitoes inject saliva into the bodies of their source(s) of blood. This saliva serves as an anticoagulant; without it one might expect the female mosquito’s proboscis to become clogged with blood clots. The saliva also is the main route by which mosquito physiology offers passenger pathogens access to the hosts’ interior. Not surprisingly the salivary glands are a major target to most pathogens, whence they find their way into the host via the stream of saliva.
To avoid this problem, mosquitoes have a digestive system which can store both food types, and give access to both as they are needed. When the mosquito drinks a sugar solution, it is directed to a crop. The crop can release sugar into the stomach as it is required. At the same time, the stomach never becomes full of sugar solution, which would prevent the mosquito taking a blood meal if it had the chance