Sexton Beetles

A recent moth trap caught some black Sexton Beetles Nicrophorus humator, we normally get the black and orange ones N vespillo. By lucky coincidence the cat caught a young rat, so we put them together in a tub and watched the result see below. I was trying to get a time lapse sequence but they did most of the burying overnight. However I was lucky enough to be watching/videoing when there was some activity and then one beetle abandoned the rat. It quite obviously wanted to escape the container so I let it leave. This was a surprise as the information I have found says  both parents tend the larvae, unless the one I filmed was a rival that had turned up? It can be seen towards the end of the video that at least one beetle was still under the rat. These like all the others we have caught had phoretic mites. Several different fly species visited the corpse one showing particular interest was a bright blue/green metallic fly.