Monday, 16 July 2012

A dance of beauty

It is late afternoon and the muggy conditions cast a sultry feel. The shade on the river provides some comfort and I stand and watch the river from the stone bridge that marks an ancient crossing point. The water is running clear again after the rain of earlier in the week and the waterweed ripples in the slowly moving current. Towards the bank, where a shaft of sunlight cuts through the shadow cast by the bank-side trees, a school of small fish dance and glint just below the surface. I have seen pike here and suspect that the small fish face an ever-present threat.

A movement catches my eye, as from the shadows emerges the jewelled blue of a banded demoiselle, the county’s most stunning damselfly. This species favours slow moving rivers and the male is easily recognised by wing band of brilliant blue. Only the male beautiful demoiselle is more stunning but, alas, it does not occur this far east. The male banded demoiselle has a blue body, dark legs and robust, paddle-shaped wings. The female is emerald green, her wings with a pale green hue but sporting no band.

This male is not alone; arcing out across the water he dances around another male that has just appeared from under the bridge. The two protagonists circle each other, seemingly displaying with a fluttering flight that is reminiscent of a butterfly. Even though there is no contact between them, I lose sight of which was the original male but assume it is the one that has looped back to the shadows from where it first emerged.

Alone among the British damselflies, it is only in our two demoiselles that courtship behaviour has been confirmed, the male responding to the presence of a female with a simple display in which he raises his abdomen and opens his wings. If she is receptive to these advances she will communicate this by alighting near the male. He will then perform an aerial dance in front of her, first moving backwards and forwards and then from side to side. If the female remains receptive then he will approach and land, perching on her wing tips and then climbing slowly down onto her abdomen. It is then that he takes a grip on her to adopt the characteristic ‘tandem position’, something that you may well have observed in other damselflies.

These damselflies are a thing of beauty, so delicate that it is difficult to equate them with the squat larvae hauled from the silty root masses of waterside vegetation. The adults make a forlorn sight when you come across them on the nearby road, a life extinguished that should have been dancing jewel-like above the river.

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