www.ukbutterflies.co.uk

Whilst watching speckled woods at the weekend, I twice saw a pattern of behaviour that I haven't seen before. One, presumably a female, was on the ground basking, wings open, in the sunshine. Another, presumably male, landed alongside it. The female immediately fell over onto its side, 'dead''. (see photo). The male flicked its wings several times then flew off. The 'dead' female remained on its side for about a minute then rose up and flew off. I assume that this was a female rejecting the advances of an ardent male. Is this recognised behaviour?

Never heard of such a thing or seen it. Sound really weird. If anyone does know the case, I will post this info on my website I am creating. Sounds like something intresting. Found a bit on behaviour, not like what you described:

Some male butterflies claim particular areas and defend them from rival butterflies. Speckled woods choose areas where the sunlight breaks through the trees. They patrol the patch and investigate every insect in the neighbourhood. They are on the look out for females to mate with or male intruders who they attack and chase away. You might see them spiralling up into the tree-tops, clashing wings with each other in battle. The butterfly that claimed the territory first usually wins

Some female butterflies use this or other behaviour to disourage males. Possibly because they are too young to mate or have already done so.

The insect in your photograph looks like a female and a fairly fresh one.

A distant relative of the Speckled Wood the Grayling behaves like that sometimes when alone with no others around, but, for different reasons .... usually.
.