Female dragonflies can lay hundreds of eggs during their adult lives, in batches over a few days or even weeks. Eggs are laid either into plant material (endophytic eggs) or deposited loosely into water (exophytic eggs). The former are elongated, but the latter are rounded and laid in a jelly-like substance which confers some protection.
All damselflies and the hawkers have scythe-like ovipositors and inject their eggs into plant stems or leaves, rotten wood or mud on or close to the surface of the water. Some damselflies submerge completely to lay their eggs, often using their still-attached partner to pull them up again afterwards. Emerald damselflies and Migrant Hawkers inject their eggs into rush stems well above the water surface, while other hawkers lay into rotten wood or other debris just above the waterline. The Golden-ringed Dragonfly lays its eggs by hovering vertically and stabbing its abdomen into stream-beds. All other British species, including the emerald dragonflies, chasers, skimmers and darters, repeatedly dip the tips of their abdomens into water, each time releasing one or more eggs that settle below the surface.
During egg-laying, male damselflies, chasers, skimmers and darters guard the females with which they have just mated, either by staying linked ‘in tandem’ or by flying in close attendance. Female dragonflies often attract attention whilst they are egg-laying as their wings rustle against emergent plants.
Eggs hatch either within 2–5 weeks or, in the case of the emerald damselflies and some hawkers and darters, the following spring.