Friday, 24 June 2011

In Search of Emeralds

A proper sunny day (first this week), a couple of hours to spare, so an afternoon visit to Far pasture Ponds in search of the Emerald damselfly. A few had emerged at Kibblesworth last weekend and this has always been a good site for them, though in small numbers.
First sighting was a brief aerial skirmish between a couple of four-spotted chasers right in front of the hide, they zipped off in opposite directions and weren’t seen again, bar another sighting of a single some time later which was just as brief.
Plenty of blue damsels in the shallows, single males buzzing around low over the water, guiding themselves through plant stems with a stop-start motion like some alien craft being manipulated by human hands in a computer game, and the thing that struck me was the fast-beating wings were nigh on invisible making them at distance look like brightly coloured moving matchsticks. Others in tandem pairs were either rested up or ovipositing, or beating off any unwanted attentions from randy lonesome males trying their chances (the mating dance is hardly a gentlemans’ excuse-me).
It was while following one of these little blue gems around that I accidentally stumbled across my quarry, an immature female specimen perched up in dense vegetation just outside the hide, metallic emerald green thorax and topside of abdomen fairly glistening in the sunshine, and close enough to reel off a couple of photos.

Emerald Damselfly Lestes sponsa (immature female)

The mature female is a mix of metallic green and red/brown (immatures pink like in this specimen) whereas the male is a combination of metallic green and pale blue, and shows a stand-out pale blue tip to the abdomen rather like a blue-tailed damsel. But the big ID feature about emeralds is that when perched, they typically hold their wings spread out an angle of about 45 degrees to the body, the only damsels to do this, so it’s easy to differentiate them from other species even at distance. But as you can see this individual has wings closed along the back like any other damsel, so out the window goes the rule book in this case, which is probably just as well to get it out of the way so early. So the rule is, a damsel perched with wings open will be an Emerald for definite, but don’t rule out a damsel perched with wings closed..
Despite a lengthy scan of the area I couldn’t locate any more Emeralds so with only one example photo to show (enough to tick off the species for the purpose of the Quest) I’ll tackle other ID features and possible confusion species at a later date when examples come to hand.
Mission Accomplished : Emerald damselfly Lestes sponsa

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