Female emperor dragonfly ovipositing (depositing her eggs).
As with most dragonflies, it is the more brightly coloured male which is easier to spot.
He will patrol his territory, a patch of water. Flying fast, up and down, with frequent jerky changes in direction, he challenges and sees off any other males who try to muscle in, and never seeming to pause for any reason.
Their movements are so fast, and so unpredictable in detail, that I’ve never managed to get a male into focus for a photo.
The females, as here, do settle as they are placing their eggs. Eggs are laid on pieces of floating vegetation. A female depositing eggs will move around a couple of places, land on a choice piece of vegetation, and curve her abdomen to place the eggs with precision.