Nicrophorus vespilloides, or common sexton beetle, has squarish wing cases that are black with red bands and button-like tips to the antennae. These beetles perform an important service in getting rid of carrion - dead small animals and birds. Males and females co-operate to bury this matter, by digging beneath the bodies to provide a food supply for their larvae. Adults show an incredible maternal care for the larvae, something very unusual in the insect world. They fly in search of new sources of food at night and readily come to outside lights. They are often seen to be host to very tiny pinkish brown mites which are not parasites but feeders on moulds which would otherwise spoil carrion as a food source for the larvae. These mites use the beetles as a way of getting about. This beetle is commonly seen at night in gardens, often in company with a related, all black species, the black sexton.
This little fella was one of my recent pool rescues, I think the mites were glad to be hitching a ride!