This pair of Azure Damselflies formed the “wheel” or “heart”, part of the complex mating behaviour of the Odonata, on a reed in the Gunnersbury Triangle nature reserve pond. As you can see, the colourful male (with the bright blue “tail”) uses his claspers to grasp the female behind the head so he obviously can’t use his tail end to fertilise her at the same time. He therefore transfers the packet of sperm, the spermatophore, to the underside of his abdomen. She uses her tail to pick up the sperm packet from there. So now you know.

Meanwhile, another male of the same species has noticed the female, and is hovering close in the vain hope of getting a chance to mate with her. Of course he looks as if he’s a voyeur, there to enjoy the spectacle; but from an evolutionary point of view, his “selfish genes” can’t be anything but “disappointed” at the fact that another male has got there first.