Ventral view of a bess beetle, Odontotaenius disjunctus (Coleoptera: Passalidae) showing the mouthparts including the mandibles with dentition, antennae, copious sensory hairs, and a "necklace" of mites in the lower portion of the image. Some species of mites are parasitic on insects, while others do no harm but hitch a ride to new habitats or feeding sites. The later mite species have evolved a relationship that benefits both, or benefits one and does not hurt the other.

Ventral view of a bess beetle, Odontotaenius disjunctus (Coleoptera: Passalidae) showing the mouthparts including the mandibles with dentition, antennae, copious sensory hairs, and a "necklace" of mites in the lower portion of the image. Some species of mites are parasitic on insects, while others do no harm but hitch a ride to new habitats or feeding sites. The later mite species have evolved a relationship that benefits both, or benefits one and does not hurt the other.