An order of small Arachnida with rounded bodies. Mites are very abundant in the soil, feeding on plant material and invertebrate animals. Some parasitic mites (e.g. red spider) damage crops and can be serious pests. Others cause diseases in animals. Ticks are blood-suckers, some being vectors of diseases such as Rocky Mountain spotted fever in humans and fowls, and louping ill in cattle and sheep.
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evidence of a close relationship. Most mites are tiny, less than 1 mm (0.04 in) in length, and have a simple, unsegmented body plan. The small size of most species makes them easily overlooked; some species live in water, many live in soil as decomposers, others live on plants, sometimes creating galls, while others again are predators or parasites. This last type includes the commercially destructive Varroa parasite of honey bees, as well as scabies mites of humans. Most species are harmless to humans, but a few are associated with allergies or may transmit diseases. The scientific discipline devoted to the study of mites is called acarology.
