The water-mite is just a speck.
Perhaps that's why he's called a "mite."
With four swift-moving pairs of legs
He quickly swims away from sight.
Sometimes he's dressed in brown; sometimes
We know him by his colors bright.
PERHAPS you have seen little red, brownish-red, or orange specks swimming near the surface of a pond. They do not jerk through the water as copepods do, but swim steadily, seemingly without stopping to rest. Each tiny speck is an animal known as a water-mite. Each mite has a smooth, fat, rounded body. Mites look like tiny spiders, but they are not true spiders. The bodies of spiders have two distinct parts. A mite's body is in one piece.
Water-mites are so small that hundreds of them can live in a single pool. Sometimes you can catch a few by scooping up some water in the palm of your hand. Often mites will be found deeper in the water, crawling over plants, or at the bottom of the pond. They come to the surface occasionally for air.
Although water-mites have eyes, they do not appear to see very well. Some mites have two eyes, each of which is double. Others have four eyes, or even five. These eyes are so tiny that they look like dark spots on the mite.
You might not expect such a tiny animal to attack his neighbors, but you will find that he does. A water-mite cannot chew his food. When he attacks an insect larva or some other animal, the mite sucks the juices out of its body, much as a spider sucks the body fluids out of a fly.
The water-mite's legs move very fast as he swims. You can see for yourself that there are four of these little legs on each side of his body. A spider also has four
pairs of legs. An insect, you will remember, has only six legs.
The female water-mite lays her eggs in the water; sometimes on the under sides of leaves, sometimes in the bodies of clams, mussels, or fresh-water sponges. Some attach the eggs to the bodies of water striders or other water insects. The larva which develops from one of these eggs is different from other larvae you have observed, because it becomes a parasite. This means that it attaches itself to the body of another animal and feeds upon it. The animal which a parasite feeds upon is called a host.
After a time the larva drops from the host and spends the remainder of its life swimming about in the open water or among water plants. At first it has six legs. As it grows and develops, it molts several times. Finally it emerges as an adult water-mite with eight legs.
|
