After the pupation of the aquatic larvae, adult mosquitoes emerge from their pupae and fly off to breed. This is a mosquito of the genus Ochlerotatus, and probably the species Ochlerotatus trivittatus (formerly placed in the genus Aedes). It is now found throughout the world.
Most mosquitoes feed by drinking floral nectar or the juices of rotting berries and other fruit. After mating, however, a female must obtain a rich dose of protein to finish the development of her eggs. For this, she seeks a large blood-meal from a vertebrate—in this case, from me. Sensitive readers should look away now.
After piercing the skin with her proboscis, she angles and explores until she nicks a venule or arteriole. Meanwhile, her salivary tube pumps out an anticoagulant that helps the flow of blood. When she has found blood beneath the skin, she holds still and, in the span of 90 seconds, distends her abdomen to grotesque proportions with as much blood as she can hold.
After withdrawing, she flies off tipsily, carrying blood amounting to two or three times her body weight. Then she finds a safe resting place. In a process taking at least 45 minutes, she releases the water content of the blood by passing it in pink droplets through her anus. After thus dumping needless weight, the mosquito flies away with proteinaceous solids in her gut that will nourish her eggs, which she lays in large numbers in rafts on the surface of water.
There are parts of the world where encouraging a mosquito to suck one's blood would be foolish: delivered in the anticoagulant saliva, mosquito-borne diseases such as malaria (carried by the genus Anopheles) and dengue fever (the genus Aedes) are serious problems in many tropical areas. Fortunately, the mosquitoes of my temperate latitude are almost totally harmless.