Witness the aerial acrobats of summer—dragonflies, the hawks of the insect world, and their delicate cousins, damselflies. From the iridescent banded demoiselle, often called Europe’s most beautiful dragonfly, to the fierce emperor dragonfly locked in mid-air "dogfights," these creatures bring a flash of color to London’s waterways. Can you tell an azure damselfly from a common blue? Or spot a brilliant emerald darting through shady ponds? On June 30th, uncover the secrets of these winged wonders—where to find them, how to identify them, and the myths that once branded them "devil’s darning needles." Don’t miss this dazzling dive into London’s most mesmerizing insects!
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Dragonflies and Damselflies
Dragonflies are the hawks of the insect world. Like hawks, they can hover and then fly at high speed. They also catch their food in mid air, although some sweep their prey off vegetation in much the same way an osprey catches fish. Their legs act as a basket in which they catch and then hold their prey. When they return to a favoured perch you can sometimes hear their strong jaws crack through the hard exoskeleton of their insect prey. With their huge eyes, iridescent metallic colours and multi-veined wings, which they cannot fold, they have a formidable almost prehistoric appearance. As they choose to emerge and fly only on warm, sunny days they are quintessentially a summer sight. Considering they have no bite or sting, it seems unfair they were also called horse-stingers, snake-feeders, flying adders and devil’s darning needles. The last name comes from the fact that children were once told they sewed up the ears of naughty boys.
These insects made their first, hesitant appearances last month but now many more are to be seen, especially damselflies e.g. large red, azure, common blue, blue-tailed, red-eyed and white-legged. Damselflies are generally smaller than dragonflies. A red one this month is likely to be the large red damselfly Pyrrhosoma nymphula. If seen close enough, its red eyes should be enough to secure its identification.
Similarly, white legs will indicate a white-legged damselfly Platycnemis pennipes. The iridescent blue damselflies are more common and rather more difficult to tell apart.
The most common is the blue-tailed damselfly Ischnura elegans which is blue-black in colour and has a distinctive blue tail. The azure and common blue damselflies are even more troublesome.
The azure damselfly Coenagrion puella has a distinct V-shape mark at the top of its abdomen, whereas in the common blue damselfly Enallagma cyathigerum this mark is more the shape of the ace of spades yet set in the same position.
The females of both these species are green and once again very difficult to separate in the field, although watching which insect a courting male chooses to chase can help
The dragonflies that might be seen this month are the broad-bodied chaser, black-tailed skimmer, four-spotted chaser, emperor and banded demoiselle. Any dragonfly seen with a noticeably broad abdomen is likely to be one of the first three. The broad-bodied chaser Libellula depressa has a powder blue abdomen with yellow spots along its sides. The black-tailed skimmer Orthetrum cancellatum also has a blue abdomen, but not as broad as the chaser. It is the black tip on its tail that points it out.
The only other dragonfly at this time with a broad abdomen is the four-spotted chaser Libellula quadrimaculata which is best identified by the distinct dark spots at the base of each of its four wings.
The emperor Anax imperator is usually identified by its greater size. In case there is any confusion, it has a blue abdomen, green thorax and long, dark stripe running along the length of its body. It is often noticed having in ‘dog fights’ with rival males. The females of all these dragonflies take a little more study to recognise.
If a green dragonfly or damselfly was seen in late May it is likely to have been either a downy emerald Cordulia aenea or the slightly larger female of a banded demoiselle Calopteryx splendens.
In early June they could be joined by the brilliant emerald Somatochora metallica. If seen together brilliant emeralds seem to prefer shadier spots. Fortunately the emerald dragonfly Lestes sponsa comes a little later in July or August when the downy and brilliant emeralds have usually ceased to fly. Epping Forest is a good place to look for all these dragonflies with the brilliant emerald said to favour Wake Valley Pond.
The dragonfly centre at Waltham Abbey is an excellent place to see a good selection of these insects. In Cornhill meadows nearby, the azure, blue-tailed and red-eyed damselfies are all recorded. There is also a chance of seeing one of the greatest spectacles of the month. Dozens, perhaps as many as a hundred, banded demoiselles can sometimes be seen chasing each other in what looks like an aerial display along the banks of the river Lee.
Both the beautiful demoiselle Calopteryx virgo and the banded demoiselle C. splendens may be seen this month. Both males are a brilliant metallic blue-green and the females an equally arresting metallic green.
All four wings of the male banded demoiselle have a thick, inky blue band across them whereas those of the beautiful demoiselle are suffused with a dark brown colour which lightens towards the tip and base of each wing. Their stunningly beautiful appearance is often enhanced by their choice of habitat, banded demoiselles flying rather ineptly beside slow-moving rivers and beautiful demoiselles preferring faster moving streams. Many people regard the banded demoiselle as the most beautiful dragonfly in Europe. Sometimes they can be seen in numbers along the Thames path at Datchet.
