Infact, I first discovered it in our conservatory and encouraged the butterfly to climb onto my hand. I then carefully took it outside to the garden and encouraged it onto a plant.
A warm humid evening and exactly the conditions the ants were waiting for. The large winged queens poured from the various ants nest around our garden. Climbing up walls and plants until they reach the highest point and then wings out stretched launched into the air.
(Three queen ants on the watering can)
By this time the small winged males follow. This is the ant mating flight. The queens head up into the sky and the males follow. In theory it is the strongest (healthiest) males that catch the queens and mate. However last year I photographed a male and female mating on the wall of our bungalow. Once mated a new queen will be fertile for the rest of her life. She returns to the ground and bites of her wings as she will no longer need them.However many don't get to mate. On the ground they are picked off by sparrows and starlings. Some end up in the webs of orb spiders.
Those that get off the ground may be eaten by a variety of birds including sea gulls.