We’re over half way through National Dragonfly Week 2016 and now we get to some of the trickier critters to identify because there are several blue-coloured damselflies. In fact, in the course of preparing this and tomorrow’s blog posts, I’ve had to call in the experts to check a couple of my photos. When my books and keys don’t quite cover it, the ‘experts’ I use are all the wonderfully helpful folks on the UK Dragonflies & Damselflies group on Facebook – highly recommended!
As we don’t get Southern damselflies (also blue) in Cardiff, the two blues I sometimes have trouble with are the Common Blue and the Azure. The key features to look out for in the Common Blue damselfly (Enallagma cyathigerum) can be seen in the photos above: no Coenagrion spur (a short black line below the other markings) on the thorax, and broad antehumeral stripes (the blue stripes on the top of the body are wider than the black stripes beneath them). The males also have that thistle-shaped mark at the top of their ‘tail’ but this is not so easy to see in the females (which, as you can see below, are not blue) because of their blacker markings. If this all sounds like gobbledygook, you can get more ID help on the British Dragonfly Society webpage.
The Common Blues are the only damselflies I’ve managed to catch in their full mating ritual, showing the ‘mating wheel’. Sometimes, when you see these, they are the exact shape of a heart … awwwww!