Erythemis simplicicollis (accompanied by a robber fly and a praying mantis)

This is an old slide scan--I think I had just got extension tubes and was playing around. I was on the ground inches away from them but they were preoccupied sharing a meal.

I wasn't there to see who acquired the meal but neither one of these guys seem like they would be sharers to me. Just curious how they ended up together. I probably should have stayed to see if the mantis took the robber fly afterward.