Acarapis woodi is an internal parasite affecting honey bees. Acarapis woodi mites live and reproduce in the tracheae of the bees. The mites are generally less than long and can only be seen under a microscope. The symptoms of infestation were originally observed on the Isle of Wight in 1904 but were not described until 1921. after the subclass to which the mites belong. Mercedes Delfinado identified the presence of Acarapsis woodi in the USA.
The mites parasitize young bees up to two weeks old through the tracheal tube openings. The female mite attaches 5–7 eggs to the tracheal walls, where the larvae hatch and develop into adult mites in 11–15 days.