While I didn’t see many adult moths in Iceland, and no butterflies at any life stage, I did see a lot of moth caterpillars, of at least two species.
The first one, which was fairly abundant at Gullfoss, crawling across the pathway down to the overlook (and regularly being stepped on by tourists), was the rather striking Broom Moth (Melanchra pisi). We saw these again at Haukadalur, but I didn’t manage to get a decent photo until towards the end of the trip, when we stayed in Skógar. This one was on the grounds of the Skógar Folk Museum, a rather splendid cabinet of curiosities.
The second species of caterpillar we saw was extremely abundant in several places. We first saw it at Haukadalur, feeding, feeding on hawkbit flowers (Leontodon species). Unlike the broom moth caterpillars, these were quite small–but their bright pink color and intricate markings made them stand out.
I am fairly sure these are the Satyr Pug (Eupithecia satyrata), a species which also seems to have been introduced to North America.
At Skaftafell, when we hiked to Svartifoss, there seemed to be a population explosion of these–nearly every hawkbit flower we passed was being consumed by one or more caterpillars. Here there was a pretty wide range of colors, from green to brown to bright pink, but my suspicion is that they are all variants of the same species E. satyrata. I may be wrong, though, and welcome correction!
More brownish, with the same markings:
A pink one, demonstrating the classic inchworm (Family Geometridae) pose:
And a green one–this one I’m less certain is likely to be the same species, but it’s still possible.
Apologies for the grainy photos: I didn’t have time to muck about with my macro lens for most of these, and apparently something was off on the point-and-shoot settings.