Nicrophorus

A carrion beeetle, also known as a sexton beetle, of the genus Nicrophorus, from the Greek for “carrier of the dead.” Found this on a mammal corpse on a path at Dead Horse Bay. The carcass was in curious state; some exposed bones were already whitened, but the main part of the body still had leathery skin/fur and did not smell pleasant. (Nothing like the Götterdämmerung of rotted chicken used to bait for carrion beetles here, though.) Not sure what the animal was: didn’t look big enough for adult raccoon; perhaps a feral cat, of which there are plenty in the phragmites.

So these Nicrophorus beetles — there are some 15 species in the U.S. — are remarkable for providing not just a nest egg of carrion for their young, but sticking around to help feed the wee larvae when they are just starting out as squirmy little rotten-flesh eaters.

The mites — you can spot two adults and see some young ones clustering on the beetle body as well — are symbionts, not parasites. Sources of carrion are extremely variable and unpredictable: so the beetles range throughout the landscape searching for it, carrying the mites (of at least four families), who eat fly larvae and couldn’t get around so well otherwise; the fly larvae is competition for the beetle larvae.

Nicrophorus marginatus is the most wide-spread of these beetles, but it’s very similar looking to N. obscurus and N. guttula, and they evidently can’t be separated based on overall appearance according to Bugguide.