Nicrophorus orbicollis

Sexton Beetle

Nicrophorus orbicollis photo from West Virginia

Family: Silphidae

Subfamily: Nicrophorinae

Length: 15-23 mm


Beetles in this genus have a well-established relationship with mites of the genus Poecilochirus. The larval mites do not harm the beetle, but use the beetle as a mode of transportation to a carcass. The carcass will then furnish the mites food, in the form of fly eggs.

At a carcass where both the beetles and mites are going through the immature stages, the two parent Sexton Beetles remain at the carcass to guard their young. Nearly the whole mite colony departs when the adult beetles depart.

European studies of Nicrophorus spp. showed the male parent beetle left the carcass first, and most of the mites rode along with him to a new carcass. Those mites left behind departed on the female parent beetle when she abandoned the carcass a few days after the male.

A good source for more information is Brett C. Ratcliffe, The Carrion Beetles (Coleoptera: Silphidae) of Nebraska (1996).

Insects of West Virginia