Several years ago, a pilot flying over the town of Picacho, Ariz., spotted a brilliant red area on the ground. It was several feet across. When he landed to take a closer look, he discovered hundreds of thousands of fuzzy red creatures with white spots huddled together. Each creature was about the size of a plump raisin. The pilot had located a massive gathering of the world's largest mite, the giant velvet mite (Dinothrombium species).
A mite belongs to the class Arachnida, whose members include spiders and ticks. This species is called "giant" because most mites are about the size of a grain of sand.
Justin Schmidt, an entomologist at Southwestern Biological Institute in Tucson, Ariz., is one of only a few scientists in the world studying these insects. In nonscientific terms, he describes his subjects as "little round things with no true head or tail," moving about on eight tiny legs.
Little is known about the mites, Dr. Schmidt says, because they are extremely hard to locate. They live 6 to 8 inches beneath eastern Arizona's sandy soil. Most of their lives are spent in underground tunnels and burrows. Schmidt believes this helps them survive the desert's cold night temperatures.
But, for up to three days in July, after the first hard rains, the mites move around above ground. Winged termites (their favorite food) are flying about then. The mites congregate to find mates. The rains moisten and cool the desert soil, making it easier to tunnel near the surface.
Above or below ground, the mites apparently have no natural enemies. Nothing preys on them. Schmidt says one reason for this may be because they "taste nasty." (Yes, he's tasted one.)
The mites' bright red color naturally warns predators to stay away. The coloring is the result of the chemical carotene. Carotene is a natural pigment ranging in color from yellow to orange to red. Carotene is what gives carrots and beets their coloring.
Unlike other mites, which feed on animals by sucking their blood, giant velvet mites eat mostly winged termites. They "don't eat people," Schmidt says. Nor are other mites as "fuzzy and adorable" as these creatures are. That makes them even more unusual, he says.
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