Mites

Mites are a diverse group of small arachnids in the subclass Acari. They range from about 0.1 mm to a few millimeters in length and inhabit almost every ecosystem, including soil and leaf litter, freshwater and marine environments, stored foods, plants, and the bodies of animals and humans. Most mites are harmless, but many have close associations with plants, animals, or people, ranging from beneficial to harmful.

Mites have a compact body divided into a gnathosoma (mouthparts) and an idiosoma, four pairs of legs as adults, and no antennae. Their life cycle typically includes egg, larva (with six legs), and subsequent nymphal stages (often two or three), followed by the adult. Reproduction is usually sexual, but some species can reproduce asexually. Mite diversity encompasses free-living detritivores and predators, plant-feeding pests, and numerous parasitic forms affecting animals and humans.

Ecology and economic significance are wide-ranging. Soil mites contribute to decomposition and nutrient cycling, while predatory mites can help control pest populations in agriculture. Plant mites such as spider mites (Tetranychus) and rust mites may damage crops, whereas stored-product mites (e.g., grain mites) affect food quality. In houses and on humans, dust mites (Dermatophagoides spp.) are common allergens; the skin mite Sarcoptes scabiei causes scabies, and other mites cause mange in animals. Chiggers (larval trombiculid mites) can bite humans and some mites are vectors for disease in certain contexts.

Taxonomically, mites are divided into two major clades within Acari: Acariformes and Parasitiformes, with numerous orders and families. Their extreme diversity and ecological breadth make mites one of the most abundant and ecologically important groups of arthropods.