Tuesday, 26 February 2008

Les Libellules (Part I) - Damselflies

Damselflies are small members of the order Odonata, first cousins of the dragonflies, who are also Odonata (which means 'toothed jaw'). Damselflies are finer and less robust than their kin and their flight muscles are less developed, allowing them to rest with their wings folded neatly above their bodies. Approximately a third to a half the Odonatae are damselflies, or the sub-order Zygoptera (meaning 'paired wings'). There are currently about 25 species that can be seen around Preuilly-sur-Claise; compared to about 20 species in the whole of Britain; 30 in the whole of France and at least 100 species in Australia.

Banded Demoiselle Calopteryx splendensIn French le caloptéryx éclatant (ie brilliant or flagrant). The scientific name echoes this theme, meaning the shining beautiful wings. So, we are all agreed then - this is a dazzling creature. You usually only see them close to rivers and they are often common and extremely visible, flapping lazily about taking frequent rests on long grass, overhanging twigs or lily pads. Well - the metallic navy blue males (above, top) are frequently seen. The equally metallic emerald green females (above, bottom) with their yellow cellophane wings are much more low profile. The species likes open running water, but not too cold, not too fast and tumbling, not too big in surface area, not too high above sea level, and not too shady. The pictured male was taken on the riverbank at Yzeures-sur-Creuse on an extremely windy day in June, so he was struggling a bit with the conditions - clinging on for dear life, as close to the ground as possible, in the hopes of lessening the buffeting. All around him, poor little newly emerged Featherlegs (see below) were being blown sideways across the sports field like little bits of straw at harvest time. The female is from the same month and we met her in the grounds of Chenonceau - clearly keeping up the château's association with beautiful ladies. Around Preuilly-sur-Claise they can be seen from May to September. For more about Demoiselles, see my previous posts here.

Migrant Spreadwing Lestes barbarusKnown as the Southern Emerald Damselfly in Britain and le leste sauvage in France ie the 'savage predator' (the scientific name means the same). The English names all reflect very noticeable features of this species' life cycle and appearance: it is strongly migratory, reaching Britain every couple of years these days; it has the typical Spreadwing habit of perching with its wings held loosely open; its range covers the whole of southern Europe (and more, as it is becoming increasingly common in the north); both sexes are an elegant combination of metallic emerald green and cream. The species is unusual in that it prefers ephemeral sites and is more often than not seen in places that do not seem promising as breeding sites, such as meadows that dry out in summer. The female pictured (above, left) was photographed in June near Roux, a hamlet just outside of Preuilly-sur-Claise. It was resting on Common Gorse Ulex europaeus at the edge of a flowery fallow field at the top of a low hill. The male (above, right) was photographed nearby on the same ridge - note the pale hooks at the tip of the abdomen, used for clasping the female when mating (both upper and lower appendages are visible if you click on the image to make it full size). The species can be seen from May to September and is common in the area.

Western Willow Spreadwing Lestes viridisKnown in Britain as the Willow Emerald Damselfly and in France as le leste vert - so the British, French and scientific name all tell you that the creature is green. This is the Spreadwing most likely to be seen in gardens in France and can be seen from July to October in the Touraine and Berry. It is one of those species that has benefitted from urbanisation because of its preference for permanent ponds bordered by trees or bushes - parks and gardens provide this habitat in abundance. They are common and usually found hanging in bushes, just as in the picture of the female above, which was taken in le Petit Pressigny in August. The species can be distinguished from other spreadwings by its pale pterostigma, which are terracotta pink once the damselfly is mature. Males also have surprisingly noticeable white upper claspers at the tip of the abdomen and inconspicuous lower appendages (other species have darker upper appendages and/or long lower appendages).

Common Winter Damsel Sympecma fuscaKnown in Britain as the Winter Damselfly (although it has never been recorded in Britain). The French name is le leste brun ie the 'brown predator'. The specific name also translates as 'brown'. I love this species. It is extraordinarily cryptic, morphing in and out of view like a shapeshifting wraith or CGI special effect in a movie. The Winter Damsels are the only European genus which overwinters as an adult, and as a consequence, can be seen all year if the weather is sunny. This male (above) was photographed on the edge of an area of wooded heath on la réserve naturelle de la Chérine in July. They are common over much of Europe, but because of their superb camoflage probably often overlooked. Presumably due to climate change, the northern limit of their range is extending rapidly. They have a preference for well-vegetated standing water with floating dead reeds.

Common Bluetail Ischnura elegansKnown as the Blue-tailed Damselfly in Britain and l'agrion élégant in France. As you can see, the name themes here are elegance and blue tails. That blue tail certainly is noticeable. A male, floating over the dark background of deep water, can be almost invisible except for the astonishing neon blue of abdominal section number 8. The females are much more subtle and varied and can be either blue, lavender, green or pale pinky orange. In this picture of a mating pair (above, left) taken at Champigny-sur-Veude, you can see how the female is being gripped behind the head and curling the tip of her abdomen up to the male's secondary genitalia. You can also clearly see the pretty 2-toned pterostigma that is a feature of this genus and helps to distinguish it from the other blue damselflies. This species is one of the most common and widespread in Europe and can be seen from April to September in most places. Unusually tolerant of very eutrophic* sites, it is normally the dominant species in such places. The picture above right is from la réserve naturelle de la Chérine in July, and I'm afraid shows the predator predated: a Robberfly Asilinae hunkering down over her lunch and looking suspiciously up at us, exactly in the manner of a dog with a bone who is afraid you are going to steal it. Life and death on the nature reserve, eh?

Small Redeye Erythromma viridulumKnown as the Small Red-eyed Damselfly in Britain and la naïade au corps vert in France. The scientific name translates as the 'greenish water-nymph' and the French is similar ('the green bodied water nymph'). This species is often seen much further out over the water than other species of blue damselflies, sitting on emergent aquatic vegetation some distance from the edge of ponds or slow flowing rivers. As you would expect from a species that habitually leaves the safety of the shore, they are swift and powerful flyers in comparison to many damselflies, and over the last 10 years have colonised the south east of England. They could be confused with the Common Bluetail, which are about the same size, but they are charcoal grey rather than the lustrous black of other blue damselflies, and both the red of the eyes and blue of the thorax and tail tip can be seen from some distance away. This male (above) was photographed on the riverbank at Bossay-sur-Claise (the village just upstream from Preuilly). They can be seen from May to September in central France and are common.

Blue Featherleg Platycnemis pennipesKnown as the White-legged Damselfly in Britain and l'agrion à larges pattes in France. The very pale blue males (see picture above left) have very obvious white 'feathered' legs. Note also the pincers at the end of the abdomen for gripping the female when mating, which you can see in action in the picture on the right. For a better view of the feathered legs, see a picture from a previous post here. The scientific name means 'flat feathery calves' and the French name also highlights the broad legs. It is by far the most common Featherleg, characteristic of sunlit lowland floodplains and rivers, and can be seen from May to September. The most likely confusion would be with teneral (immature) specimens of other blue damselflies. Although they are actually quite large and robust as damselflies go, their ghostly colouration gives the impression of something ethereal and delicate (or if you are feeling more prosaically inclined, something feeble and ailing). Watch out for the males displaying by bouncing and fluttering in the air whilst dangling those fine feathery legs. They are very susceptible to pollution and their disappearance from an area can often be a sign of problems.

Finally, enjoy this offering from French animators, Miniscule TV. It is a shame that it has been over compressed so the quality is rather poor, but amusing nonetheless. If you liked it, you can find several more of their little vids on YouTube.

*Water having such a high level of dissolved organic nutrients that it is more or less devoid of oxygen. A particular problem of water bodies in agricultural areas because of fertilizer runoff (both artificial and natural).

Susan

[Note: this post has been edited to correct my misidentification of the Small Redeye.]

9 comments:

chm said...

Once again, I repeat myself. Very interesting and informative post, with beautiful pictures. I wish we had, here in the desert of Southern California, such strikingly elegant creatures, but we have too much wind and sand!

Susan and Simon said...

They are such lovely twinkly creatures, and so astonishingly adapted to any habitat except extreme cold, so you do get them in the desert. See http://www.desertusa.com/mag98/nov/papr/drangonflies.html and http://klok.smugmug.com/gallery/1161322_ZE3rq#54209682. Just sit and watch at any little pool. Quite often they will come to watch you, as they are so visually oriented, they will recognise a new object in their territory.

chm said...

Thank you for the links. I enjoyed looking at those ethereal creatures.
I live near that large body of water called the Salton Sea. Except for that extremely salty "manmade" lake there is no other water available in the vicinity. And puddles left after very rare rains dry up very quickly.

Susan and Simon said...

The Salton Sea and a wetland project to the south on New River seem to be pretty highly rated amongst the bird watching community for their dragonfly watching opportunities. I'm not sure how many species - at least a dozen though, and some of them seem to occur in large numbers.

See http://www.birdforum.net/showthread.php?t=9962 and http://www.southwestbirders.com/new%20river%202001.htm

It looks a fascinating area. Do people around there have ponds or provide water of some sort for wildlife in their gardens or is it impractical/not the done thing?

chm said...

Yes, this is a fascinating area. But here, in Salton City, population 1000 plus nothing much happens.
Our rich neighbors to the North, 35 miles plus, have pools, lawns and an infinity of golf courses, so they waste water as fast and as much as they can, all that in the desert, mind you.
Ten to thirty miles to the West we have the Anza-Borrego Desert State Park, the largest state park in the US. In good years, that means after good rains, the wild flower show is spectacular.
Thirty miles to the South, at the bottom end of the Sea, we have at least two bird sanctuaries, where I used to go birding when I was younger. There, with the extensive agricultural operations, there is a lot of water "floating" around.
Here, In S.C., people are discouraged to have standing water of any kind because of the threat of the West Nile virus. We don't have gardens, as such. This is mostly sand and it get too hot in the summer to keep anything growing without ample supply of water. We have cacti, of course, palms trees, the imported Tamarisk, and native trees as Palo Verde and Mesquite. Most new people coming to the area don't even bother to water the existing non native flora and let it dry up. That's a shame!
Thank you for both links. I'll come back to the one on the New River regularly.

Susan and Simon said...

http://pruned.blogspot.com/ (clickable link on right under 'Blogs we read') is always worth reading with regard to water management and purification projects.

geeko said...

Nice to see you interested in French species. I'm afraid we have less to offer than Australia, though.

Anonymous said...

Nice pics, but the Redeye damselfly you show is not a Large Redeye, but a Small Redeye (Erythromma viridulum). You clearly see the bleu on the sides of segments 2 and 8
Marc

Good work anyway on your blog

Susan and Simon said...

Merci bien Marc - thanks for letting me know. For me, the Small Redeye is actually a better record, so I'm quite pleased :-)
Geeko - thanks for taking a look too. Australia may have many more species, but until recently, no field guide, and no widespread recording like Europe. I checked out your blog too, and it is most informative - well done!
Susan