Those are mites, or more specifically Mesostigmatid mites. They are hitchhikers frequently found on insects associated with dung or carrion. These resources tend to be very patchy in the environment and mites are so tiny they can't disperse well by themselves, so they take advantage of beetles, flies, millipedes etc. to get there faster. These mites are predators that feed on worms or other small critters, they're not parasites.
Looks like your beetle has at least two mite species on it: the lighter ones with two separate dorsal shields likely belong to the genus Poecilochirus, and the darker ones with undivided dorsal shields are unfamiliar to me. They might belong in the family Macrochelidae.