These aren't in my worm bin, but I'm sure they would hurry in there too if I put the manure in it.

For the last few weeks, I've noticed a great deal of bug activity on/in the dog manure in the yard. These aren't the standard flies and such but a bug that I've never seen before.

Description:

Approx 1/8" in length. The body is divided into two segments. The first is the head which is perfectly round. The second is the body which is an elongated oval. The body is black except for a thin white stripe where the head meets the body section. They're too small for a leg count.

Literally hundreds of these are showing up on every piece of manure. They seem to be either eating it or carting it away. If the manure is left out for more than a couple hours, they turn it into something like swiss cheese, tunneling through it everywhere. No matter where it is in the yard, they find it.

Does anyone have an idea of what they might be? I only noticed them appear after switching to a higher quality dog food if that's significant at all.