|This pair of Orange-tips mated overnight, just like the Small Tortoiseshells|
I believe that this happens when butterflies mate/join late afternoon. The sun goes in, becoming cold, so they roost where they are and stay joined overnight. The following day they go their separate ways, once its warm enough. It is thought that mating saps the males energy, which is why males tend to take in salts/minerals from Horse droppings, damp soil etc., to build-up their energy levels. Mating for the average species of butterfly probably only lasts between 40-60min. So why mate all night? As this act could well prove to be fatal to the male butterfly. Both male and female Orange-tips flew off after their marathon copulation.