Mites (Acari or Acarina) are a taxon ofarachnids.
They are generally tiny in size : some are microscopic, measuring just a few tens of micrometres, with the largest not exceeding 2 cm (except for blood-gorged ticks which, in tropical-equatorial species, can reach the size of a cherry ).
The body is particularly compact for an arthropod due to the fusion of the prosoma (equivalent to the cephalothorax of other arthropods) and the opisthosoma (or abdomen) into a single mass and the virtual disappearance of all traces of segmentation.
There are almost 50,000 recorded species, but the real diversity of the group is probably more than a million species. The variety of their lifestyles (habitat, ecological niche, feeding habits, etc.) is unparalleled among arachnids.
Many live freely in the soil or water, but mites have also developed a wide variety of relationships with other living beings, both animal and plant, ranging from phoresis to endoparasitism. In particular, there are a large number of parasitic species, which can be pathogenic to plants, animals or humans.
Among the best-known are ticks, the sarcopte responsible for scabies, the varroa parasite of bees, dust mites (Dermatophagoides pteronyssinus, for example), which can cause allergies in some people, and augusts.
Television documentaries with mistranslations of the English mites (" acariens ") have led to confusion in French between the real " mites " (moths in English) and house dust mites.
