www.ukbutterflies.co.uk

... being coordinated by members of the Herts and Middlesex branch of Butterfly Conservation. See

http://w-album.hertsmiddx-butterflies.org.uk/

Cheers,

- Pete

Tried the nearest 1km square at the weekend - not a sign of elm but it wouldn't surprise me if I missed it - the square was 50% woodland and a couple of green lanes with good butterfly potential. Being high up on the Mendips spring had not quite reached the place yet. The bluebells were not out and the only butterflies to be seen were hibernators.

I find there is plenty of elm around where I live and work, albeit distributed somewhat patchily. I will have a look for the butterflies there when their flight-time comes.

When searching for other Hairstreak ova, I have found w-album ova on Sloe also known as Blackthorn ( Prunus spinosa) and reared fine examples which fed up on the Blackthorn flowers.

Females prefer the mature Wych elm ( Ulmus glabra) to lay in Glos but also lay on the saplings which are so immature, are not ready to produce the preferred Wych Elm flowers the larvae first feed on. I have once or twice discovered mature w-album larvae on these immature saplings. The young larvae I presume start to feed on the unopened or partially opened young and succulent leaf buds, moving onto the more mature leaves as the larvae become larger.

I have found a number of these in and around Bath in the last couple of weeks:



Today however I found another larva on elm, clearly the same shape but a very different colour. Do the larvae come in two forms, or is the change of colour a sign the larva is just about to pupate?



From the same tree, what appears to be a white-letter hairsteak pupa.

Yes, as you suspect, the change in colour is a sign that the larva is ready for pupation.