Mosquitoes are small flies that look a lot like their cousins in the fly family, the crane flies and midges. Female mosquitoes, however, drink blood from vertebrate animals.
Adults have one pair of transparent wings; upon close inspection, you can see a fringe of hairs and scales along the edges and veins of the wings. The legs are long, and there is a long proboscis (pro-BAH-siss) that is used like a straw for drinking. The antennae are featherlike in males.
Larvae, called “wrigglers,” are aquatic, with a large head and thorax and narrow, wormlike abdomen; they typically hang just below the water surface, breathing air through tubes at the end of the abdomen. When disturbed, they wriggle downward.
Pupae, called “tumblers,” are curled like a comma and also hang just under the water surface, breathing through air tubes.
Adult length (not including appendages): about ¼–½ inch.
Habitat and Conservation
All need standing or quiet water in which to lay their eggs, but as adults, different species have different habitats and active times. Some prevail near floodwaters or temporary pools, others in houses, in irrigated pastures, marshes, or streams. Being rather weak fliers, most adult mosquitoes are less active on breezy or windy days, and more active when the air is still. Some species bite in the day, while others are most active at dawn, dusk, or night. Eliminating standing water is an effective way of reducing mosquitoes. Follow pesticide directions carefully. Educate yourself about the many ways to manage mosquitoes.
Larvae eat algae and other microscopic organisms that abound in water; a few types prey on other mosquito larvae. Adult males feed on flower nectar; they do not drink blood. Except for a few species, adult females need the protein in blood in order to reproduce. Some species feed only on certain types of animals; some, for example, only drink blood from frogs, and others only from birds. Some mosquitoes bite nearly anything that breathes. And some prefer the blood of humans.
Worldwide, mosquitoes transmit the viruses for West Nile, Zika, yellow fever, dengue fever, and more; the parasites that cause malaria and elephantiasis; and the bacterium that causes tularemia. They transmit heartworms to dogs. The most effective way to control mosquitoes is to eliminate breeding sites: standing water in clogged gutters, old tires, flowerpots, ditches, and so on. Use nontoxic mosquito dunks in places that regularly collect water. Reduce bushy vegetation where adult mosquitoes rest. Use a repellent, such as one containing DEET. Mosquitoes are not strong fliers, so breezy places, and breezy weather conditions, will have fewer mosquitoes.
After a blood meal, females rest a few days and develop 100–400 or more eggs. These they usually deposit on the water, flying close and tapping the abdomen onto the surface. Eggs hatch in a few days and spend about a week as “wrigglers.” The pupal stage lasts 2–3 days, after which adults emerge, climbing out onto the water surface. Adults mate within a few days, and females begin seeking blood. The life cycle usually takes a few weeks, but when conditions are right, it can take only 10 days.
Mosquitoes plague us with their whines and itchy bites as well as with the serious and life-threatening diseases they transmit to humans and other animals. Their economic impact is staggering.
Historically, the avoidance of “malarial” swamps determined where towns did or didn’t develop. It is one reason wealthy people (who could pay for higher-priced land) have historically preferred building their homes on high land, away from water, flooding, and still, sultry air. Look at the older parts of a city, and notice how most of the big mansions are built on hilltops.
Although some mosquitoes prey on other mosquitoes, most are parasites.
Some disease-causing microorganisms need mosquitoes to complete their life cycle.
Mosquitoes are an important part of aquatic and land food chains. The larvae are an important food for many aquatic animals, including fish, and birds and other insects devour mosquitoes on the wing.