There is a species of tiny spider-like creatures that live inside the lungs of bees!
Talk about a world inside of a world. The “honey bee tracheal mite” is an internal parasite of honey bee. They are related to spiders and thus have 8 legs, and live and reproduce in the tracheae of the bees. The female mites stick about half a dozen eggs to the tracheal wall. The larvae hatch and develop in 11-15 days to adult mites.
Each mite infests young bees for up to two weeks. They pierce the tracheal tube walls with their mouth and feed on the haemolymph of the bees. More than a hundred mites can populate the tracheae and thus weaken the bee.