As an aside from all this, I'm someone who detests dogs, but unfortunately I have to walk the one my OH bought when her shifts mean she cannot.
One one such walk a couple of years ago I got chatting to the lady who doese butterfly transects locally. She told me she had seen a Red Admiral land on a bit of dog poo and stay there for a good 10 minutes. On asking why a butterfly would do that I was told that in order to breed the Red Admirals have to put out some pretty powerful pheromones, and whatever it was getting from the dog poo helped with that.