This male Yellow dung fly, Scathophaga stercoraria, as the sole occupant of a very wet cowpat after a rain shower. Yellow dung flies are sexually dimorphic, males and females differ in size and colour: males are much larger and brighter yellow than the female. Larger males are better competitors, better to defend a bit of cowpat from other males. Males spend much of their time on the cow pat, while females only come to the cowpat to mate and lay eggs. Dung flies actually feed on other flies and insects attracted to the dung, but also on pollen and nectar and the dung itself, while the larvae will develop on the dung. Although of Yellow Dung flies are associated to large animal dung, especially cow pats, I've had them in the garden before, where they might have been attracted to compost.
A pair of mate guarding dung flies in the garden, 26/08/2006, illustrating their sexual dimorphism.