Acarina

Acarina is a traditional term used to refer collectively to the mites and ticks, a grouping within the arachnid lineage known as Acari. In modern taxonomy, the informal name Acarina is largely supplanted by Acari, which is divided into two major lineages: Acariformes (mites) and Parasitiformes (ticks and some mites).

Morphology and development: Members are small eight-legged arthropods, with adults typically having eight legs and larvae often possessing six. They display a wide range of body forms adapted to diverse lifestyles, from free-living soil dwellers to highly specialized parasites. The life cycle generally includes egg, larva, nymphs, and adult, with variations among species in development and host association. Parasitic forms feed on blood or tissues of hosts, while many mites are detritivores, predators, or plant associates.

Ecology and importance: Acari are ubiquitous and occupy nearly every habitat, from soil and leaf litter to animals and plants. Economically and medically significant groups include ticks (Parasitiformes) that vector diseases such as Lyme borreliosis and other illnesses, and mites (both Acariformes and Parasitiformes) that can cause mange, scabies, or agricultural pests. Some mites, like Varroa destructor, are major parasites of honeybees and have substantial agricultural impact. Others play beneficial roles as decomposers or soil engineers.

Etymology and status: The name Acarina derives from Latin acarus, meaning “mite.” Although historically widely used, Acarina is now considered obsolete or informal in formal classifications, with Acari serving as the preferred taxonomic term for the group. The concept remains common in older literature and certain non-systematic contexts.