The Emperor of Knepp

My Pan-species List is going along quite nicely and I think I will comfortably reach 2000 species by the end of the summer holidays, which is my target. However, I haven’t added another new butterfly species for a very long time. So on Tuesday, that is what I set out to do.

Knepp Estate near West Grinstead is one of the best places in Sussex to see the elusive Purple Emperor butterfly. Purple Emperors spend most of their time in the canopy of large Oak trees and there are many huge trees at Knepp, which also makes the estate good for saproxylic beetles. Saproxylic beetles are beetles that depend on dead or dying wood. Also, due to Knepp being part of a rewilding project, there is lots of dung about. Rewilding is where you take a location and try to restore it to the state that it was in many centuries ago. This involves using substitutes for wild boar (Tamworth pigs), aurochs (long-horn cattle) and other animals. Dung is good for Purple Emperor butterflies because they can harvest moisture and nutrition from it.

Apparently, to entice Purple Emperor butterflies down from the canopy, you need a banana and some fish paste. On Tuesday we chose fish paste, and we spread some on a slice of bread. After we had walked down a nice track to get to the Purple Emperor hotspot in the centre of the estate, we climbed up onto a tree platform and I unwrapped my fish paste bread. It wasn’t long before the flies began to arrive, but Purple Emperors were no where to be seen.

The weather conditions were far from ideal for the Purple Emperors. It was dull and very windy, there was no sun to warm them up and at the tops of the trees even these very large butterflies would have difficulty flying. However, we kept searching, walking along rides where we hoped the butterflies would show. We were just about to head home when the sun miraculously came out from behind the clouds. It immediately warmed up but we didn’t think it would last for long. We carried on walking down the ride when I nearly stepped on a long black thing. To my surprise it exploded from the ground just beneath my looming foot and flew towards the hedge on the side of the ride. I had nearly stood on a Purple Emperor! I hadn’t noticed it because its wings were closed making it look like a black twig from above. It wasn’t the best of views, but I had seen a Purple Emperor!

Sooner than I thought, it came back and landed on the track, where it probed the ground with its proboscis. It was picking up minerals from the dirt that it wouldn’t be able to get in the oak canopy. As it spends most of its time in the trees, it doesn’t feed on flowers which is very interesting. Instead, it most commonly feeds on the honeydew that is excreted by aphids and also sometimes on sap. Another interesting point about the Purple Emperor is that they are sexually dimorphic, which means that the males are different to the females. The males are much more beautiful and have a brilliant purple sheen when the wings are at a certain angle to the sun. However, the female is larger, dull brown and never has the purple sheen of the male.

While the butterfly on the ground was picking up minerals, I spotted a second butterfly flying around at head height. However, it was too wary to come down and retreated back to the canopy. The male on the ground was also flighty, but I did manage to get a few photos from a distance:

So, that is my 33rd butterfly species. Which butterfly will be next on my list?