To all the swift replies, thank you very much! Lots of additional interesting information to think about, and willows, aspens and poplars to starting hunting about in! I hope it doesn't appall the contributors to know that I was actually on holiday during that period, and not knowing what to do with...

Hello there, I'm another new user, simply because I found a rather lovely caterpillar on holiday in Donegal (NW Ireland). Apologies if this is a really common species, but I'd love to know what it is! The two photographs show said caterpillar on my father's hand, and the caterpillar is somewhere bet...