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Thursday, 17 June 2021

Headstands

Azure Bluet (Coenagrion puella)
Right now, the new pond is serving as the garden's biggest pickup bar. There was a frenzy of activity a few days ago, with more than a dozen pairs of Azure Bluets (Coenagrion puella) sprinkled across the pond, egg-laying on the surface vegetation. At least a dozen other males restlessly patrolled the water's edge, waiting for passing females. Once he'd found a female, the male clamped onto her head using claspers located at the end of his abdomen. He continued to hold on – in effect standing on the female's head – while his sperm packet was transferred over to the female, while the eggs were fertilised, and while the female carefully positioned each egg on the underside of leaves and algal mats in the pond. Only when she was done egg-laying did he finally let her go.

The Azure Bluet is one of the most common damselflies over much of Europe, east to central Asia. In the UK, it's widespread throughout England, Wales and lowland Scotland. It generally prefers small, still ponds like ours, though it's also found along the edges of larger water bodies and small streams. Though the male is quite similar to several other species (including the Common Bluet) it can be distinguished by the black, square-bottomed "U" on its first abdominal segment and by the thin black "thorn" that extends into the blue on the side of its thorax. Azure Bluets fly primarily from May through July, though some are seen as early as April and others as late as September. Judging by the number of eggs laid, the pond will soon be swarming with damselfly larvae, which will feast on the Daphnia population and be feasted on by the Smooth Newts and various diving beetle and dragonfly larvae. It's one big jungle in there!

Pair in tandem


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