Alice Borchert, age 9, of Chattanooga, Tenn., for her question:P01
HOW MANY KINDS OF MOSQUITOS ARE THERE?
A mosquito is an insect that spreads some of the worst diseases of man and animals. There are more than 2,500 species of mosquitos and they can be found in all parts of the world, even in the Arctic.
Scientists classify species of mosquitos into about 100 groups, each called a genus. About 150 of the 2,500 species can be found living in the United States and Canada.
Some mosquitos carry the germs that cause such serious diseases as encephalitis, malaria and yellow fever. When a mosquito bites or even touches any object, it may leave germs behind. Many kinds of mosquitos do not spread disease, but they have painful bites.
Actually, the mosquito does not really bite since it cannot open its jaws. When a mosquito "bites," it stabs through the victim's skin with six needlelike parts called stylets, which form the center of the proboscis, or tube like part of the mouth.
The stylets are covered and protected by the insect's lower lip, called the labium. As the stylets enter the skin, the labium bends and slides upward out of the way. Then saliva flows into the wound through channels formed by the stylets.
The mosquito can easily sip the blood because the salvia keeps it from clotting. Most persons are allergic to the salvia and an itchy welt called a "mosquito bite" forms on the skin.
Only the female mosquitos "bite," and only the females of a few species attack man and animals. They sip the victim's blood which they need for the development of the eggs inside their bodies. Liquids provide the insects' only food. Both males and females of many species sip plant juices as their main sources of food.
After the mosquito has sipped enough blood out of its victim, it slowly pulls the stylets out of the wound and the labium slips into place over them. The insect then flies away.
The hum of a mosquito is the sound of its wings beating. A mosquito's wings move more than 1,000 times each second. A female's wings make a higher tone than a male's wings and the sound helps males find mates. Mosquitos are actually flies, since they are insects with two wings. The word "mosquito" is Spanish and means "little fly."
A female mosquito will lay from 100 to 300 eggs at a time, depending on the species. One female may lay as many as 3,000 eggs during her lifetime. The eggs are laid through an opening called the ovipositor at the tip of the female's abdomen.
Females of most species lay their eggs in water or near it, but each species has a favorite spot. Some like swamps while others prefer marshes. Some lay their eggs in hidden polls that form in tin cans, fallen logs or hollow tree stumps.
All species lay eggs that require moisture to hatch, but not all of them are laid in water. Some drop their eggs in mud left by a flood.
Others lay them in ponds that have dried up and the eggs hatch after rains fill the ponds with water.