26th July 2012
Eager to make the most of the warm weather whilst it stays, we headed to the Brecks to look for Scarce Emerald damselflies. These are known not only for their rarity, but also because of their similarity to Emerald Damselflies. Indeed the best way to tell males apart is the anal appendages, which as you can expect are rather small. As both species were present at our site, I adopted a policy of trying to photograph as many individuals as possible. We found several Emerald sp. in long grass, and I then went to check out the vegetation along the edge of a large pool. I found lots of Emeralds, but they were too far away or too skittish to get decent pictures. On my way back, birds started giving alarm calls and I looked up to see a large Goshawk flying over! I called Cathy and we were able to watch it soar over the clearing and then glide off northwards.
Returning to the Emeralds, Cathy managed to expertly stalk and photograph a female Emerald Damselfly, and copying her technique I managed to get some photographs of a male Scarce Emerald. I have included pictures of female Emerald and Scarce Emerald - note the different shape of the markings on segment 1 (2 squares in Scarce Emerald, 2 tear drops/triangles in Emerald. The female Scarce Emerald is noticeably stockier. The male Scarce Emerald has curved outer anal appendages. The inner appendages are also curved, but this means that they aren't properly visible as they are covered by the outer ones (in male Emerald you would be able to see the straight inner appendages on the photo). Note also the bulge to segments 8 and 9, and the prunescence only coming 2/3rds of the way down segment 2.
Female Emerald Damselfly. Photo: Cathy Thomas
Female Scarce Emerald Damselfly
Male Scarce Emerald Damselfly