When admiring Agrion (Calopteryx) virgo as it flutters amongst the bankside vegetation of fast-flowing streams, it is easy to understand how this damselfly is known as the Beautiful Demoiselle (demoiselles are species of damselflies with pigmented as opposed to clear wings!). Damselflies differ from dragonflies by holding their wings alongside their slender bodies when at rest, whereas dragonflies have more robust bodies, are fast and agile flyers, and hold their wings at right angles to their body when resting.
The specimen illustrated is of a female; the male has dark coloured wings with a blue iridescence and a metallic blue-green body. It is territorial, resting on vegetation near the best locations for females to lay eggs, and spreading wings and making other visibly threatening gestures at any approaching males.
Following mating, the female may lay several hundred eggs on floating plants. After about two weeks, these hatch into predatory nymphs (sometimes referred to as ‘larvae’) which feed and develop on other insect larvae in the water. They take up to two years with 10 or more moults before they develop into adults.
