Observed on stone wall of a cottage in South Wales. Approx 2cm long .(Quite large)
No interactions present.
It does look like some of the other pictures of Mayflies. Can't remember if it had wings. Do they lose them like flying ants??
This male of the upwinged order ephemeroptera is most likely to be in the second stage (imago) of its very short adult life defined mostly by the vivid coloration of the body and legs. A side on view showing transparency of the wings would confirm or refute this.
The wings can be seen from the vertical viewpoint running together down from the thorax and beyond the abdomen between the two tails. Mayflies/Olives do not lose their wings at any point. A few of the species have a 2year lifecycle from egg/nymph/sub imago/imago but for most it is 1year. The final adult imago stages are unfortunately measured in hours rather than days.
Tragic perfection of beauty.
Lat/Lng: 51.915646, -4.080548
OS grid ref: SN570261