Scorpions Spiders Mites and Ticks: Arachnida

Physical characteristics: This microscopic, wormlike, almost transparent, or see-through, parasitic mite is 0.00394 to 0.0178 inches (0.1 to 0.45 millimeters) in length. The head is distinctly separated from the body. The abdomen is finely wrinkled and tapered. Adults have eight stumplike legs, each with claws. The needlelike mouthparts are used for eating skin cells.

Geographic range: These mites live worldwide, wherever people live.

Habitat: This mite lives in human hair follicles, the small sacs that surround the root of each hair. The mite might be found anywhere on the body but prefers the follicles of the face, the roots of eyelashes, and the oil glands of the forehead, nose, and chin.

Diet: The hair follicle mite eats human skin cells.

Behavior and reproduction: Follicle mites are common parasites and spend their entire lives on their human hosts. They live in hair follicles and eyelashes, burrowing head first into the root. They move onto the skin at night at rate of 0.4 inches (1 centimeter) per hour.

Females may lay up to twenty-five oval eggs on one hair follicle. Young mites resemble adults. First-stage larvae (LAR-vee), or young mites, are legless, but later stages, before the mite becomes an adult, have six legs. Follicles may become tightly packed as the mite larvae grow. Adult mites leave follicles to mate and then find new follicles in which to lay eggs. The entire life cycle of the mite, from egg to adult, takes about fourteen to eighteen days.

Hair follicle mites live in hair follicles and eyelashes, burrowing head first into the root. (©Andrew Syred/Photo Researchers, Inc. Reproduced by permission.)

Hair follicle mites and people: Mites are basically harmless, and humans who harbor them often show no signs of infestation. Follicle mites are not known to transmit diseases, but large numbers in a single follicle may cause itching and other skin disorders, especially in the elderly.

Conservation status: This species is not endangered or threatened. ∎