Honeybee tracheal mite. Light micrograph of a honeybee tracheal mite (Acarapis woodi). Mites are related to spiders, and many are parasites of other animals. This mite lives in the tracheae (airways) of honeybees (Apis mellifera), causing a condition known as acariosis or acarine disease. It makes the bees lethargic and unable to fly. Acariosis can cause entire honeybee colonies to collapse. The tracheal mite has a wide, flat body with four pairs of legs. A small head (far right) bears mouthparts for feeding on the blood-like haemolymph of its host. The mite's body has several long hairs, but is otherwise smooth. Magnification: x450 when printed 10cm wide.