Discovering Species – Beautiful Demoiselle

I was lucky to spend a spectacular week on the Isle of Mull recently. One afternoon, we set out on a relaxed walk/climb up the hill behind our camping spot. Having reached the top, enjoyed the view, chilled with the sheep, dodged the naughty Shetland ponies and been pleased with our solo-discoveries of wild orchids along the way, we came across a small stream on the way back, with some amazing-looking metallic blue damselflies with almost opaque metallic-looking wings that we’d not come across before. After looking them up (I’ve found that the British Dragonfly Society website have excellent ID-help pages for Dragonflies and Damselflies), they were unmistakably male Beautiful Demoiselles (females are metallic green-bronze with pale brown wings).

For the interest of myself (and anyone who happens to read my blog), I thought I’d do a little more research about this special-looking species.

• Scientific name – Calopteryx virgo
• Where to find – In the UK, The Wildlife Trusts say that Beautiful Demoiselle is found west of a line drawn between Liverpool and Folkstone. According to the IUCN Red List, Beautiful Demoiselle is common all over Europe, and more specifically can be found in Albania, Andorra, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Guernsey, Hungary, Ireland, Isle of Man, Jersey, Kazakhstan, Kyrgyzstan, Latvia, Liechtenstein, Lithuania, Luxembourg, Mongolia, Montenegro, Morocco, Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Russian Federation, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom, Åland Islands.

• Conservation status – Least Concern globally on the IUCN Red List but extinct in Italy and possibly extinct in Algeria
• Habitat – Prefers to reproduce in small/medium running waters with partial shade in hills and mountains, particularly in streams and rivers with gravel and stone beds. Can be found in lowlands but in much lower numbers.
• Life cycle – I found an excellent description of the life cycle of the Beautiful Demoiselle on the Denbighshire Countryside website – interestingly, the males attract their mates with a fluttering display flight, a courtship behaviour only seen in two other dragonfly and damselfly species in Britain. The female lays eggs on vegetation in the water course, which hatch after 14 days. The larvae then live in the water for two years before climbing out of the water onto vegetation and shedding their larval skin. Adults survive for a few weeks and are most likely to be seen between late May and late August.
• Diet – Both as larvae and as adults, Beautiful Demoiselles are predators, catching and eating other insects (doing so on the wing as adults).
• Behaviours – Males are said to rest on bankside vegetation awaiting females (- likely what the males we saw on Mull were doing!)
• Interesting fact – The Beautiful Demoiselle is the only British Damselfly with opaque or coloured wings. Banded Demoiselles also have coloured wings, but the males of this species only have partially coloured wings with a dark “band” (hence the name), and the females have yellow wings. Both Banded and Beautiful Demoiselles belong to the Genus Calopteryx, (also known as “jewelwings”) which comes from the Greek words kalos, meaning beautiful and ptery, meaning winged.

I continue to be astounded by the variety and out-of-this-world “differentness” of invertebrates, and find it very rewarding to discover and learn more about species which are new to me. Taking the time to find out more about species helps in appreciating their complexity and place in the world, as well as helping me remember them for next time I see them!

I look forward to the next time I see one, as they certainly live up to their name.