UPDATE 20JUL11: With the start of the Big Butterfly Count on 16 July, the discovery of the Cryptic Wood White (which looks identical to the ‘English’ and Réal’s Wood White) has been officially announced. The major news organisations have published articles on it – Patrick Barkham’s is especially good:
http://www.guardian.co.uk/environment/2011/jul/13/new-butterfly-northern-ireland-wood-white
My original article begins here:
A bit of background: we have two species of Wood White butterfly in Ireland: the wimpy Wood White in the Burren, and Réal’s Wood White everywhere else.
Or so we thought.
Research published this year shows that the Réal’s Wood White butterfly Leptidea reali (found in Europe and Ireland) is actually two cryptic species, reali and juvernica.
http://www.biomedcentral.com/content/pdf/1471-2148-11-109.pdf
http://www.nature.com/ncomms/journal/v2/n5/full/ncomms1329.html
Now, the Dublin Naturalists’ Field Club has posted a web page explaining the history of the Wood Whites in Ireland and declaring that:
“the species that occurs outside the ‘Burren’ in Ireland is now to be known as Leptidea juvernica, the Cryptic Wood White or Bánóg duaithne choille.”
http://www.butterflyireland.com/cryptic_wood_white.htm
Nothing has changed in real terms (excuse the pun!) – it’s not an exotic immigrant and the butterflies don’t even know they’ve got a new name – but it’s exciting nonetheless!
(Personally, I’d have preferred the “Irish Wood White” but as it’s found across Europe to Russia I bow to the professionals!)
So, in summary, Réal’s Wood White is no longer considered an Irish butterfly, and the Cryptic Wood White is.