Gabe Brody, age 11, of White Plains, N.Y., for his question:
WHAT IS THE DIFFERENCE BETWEEN A TICK AND A MITE?
Scientists do not separate mites and ticks on the basis of structure, but most people call the smallest species mites and the larger ones ticks. They belong to an order of animals called Acarina. Generally speaking, these creatures are called mites.
A mite is not an insect. It is closely related to the spider and the scorpion.
Some mites live on land while others live in water. Some are too small to be seen easily with the naked eye and must be studied under microscopes.
The male mite usually has a saclike body with a slight dividing line between its abdomen and thorax, and has four pairs of legs. The mouth has piercing and grasping organs. The digestive system starts in the sucking beak.
The young larvae of most species of mite hatch from eggs and have six legs. They shed their skins and change into nymphs with eight legs. After one or more other moltings, the nymphs change into adults with four legs.
A few species of mites prey on plant, lice or aphids and others on insects and grasshopper eggs. But the majority of mites do not help people and they are considered pests.
More than half the different kindf of mites live at least part of their lives as parasites. They suck the blood of animals or the juice from plants, and eat cell tissues as well.
Other mites eat feathers, cheese, flour, cereal, drugs and other stored products. Several kinds of mites burrow into the skin of man and other mammals, especially horses, cattle and sheep. They cause the skin to break out and itch, forming scabs and mange.
The troublesome chiggers or red bugs which torment many people in the woods are mites. Another kind which attacks man is a long wormlike mite which burrows into the hair follicles and the oil glands.
Many of the mites can be killed with special sulfur preparations.
Several kinds of mites attack poultry. The best known is the common chicken mite which, like the bedbug, sucks the blood of its victims at night and hides in cracks during the day. Kerosene can be used to kill the chicken mite.
Sometimes a mite called the red spider destroys greenhouse plants. The peartree blister mite damages fruit frees.
Call mites form small lumps on leaves and twigs. Unlike other mites, they have only two pairs of legs.
Clover mites attack plants and fruit trees. In the south they spend the winter on clover plants.
Other mites attack bulbs and roots of plants. A few species prey on plant leaves and stems exclusively.
One type of mite attacks man by burrowing under the skin, causing a severe itching and irritation known as scabies or sarcoptic mange. Eggs are laid in tunnels under the skin, parallel to the surface, by a female who is only one sixtieth of an inch long. The irritation caused by her tunneling and by the feeding activities of the larvae is often difficult to diagnose.