Note: The seasonal time frame described in this text applies mostly to European damselflies, but may not for those of other regions.
The damselfly has three developmental stages in its life: egg, larva and imago (adult). The first stage begins when the female uses her ovipositor to lay her eggs in aquatic vegetation or into mud. She does this in summer, before dying in early autumn at the latest. The eggs of some species lie dormant over winter and hatch in the spring, while others will hatch a few weeks after laying (larvae usually overwinter in the mud).
When the damselflies hatch they are nymphs (larvae). These nymphs swim by a powerful sideways movement of the abdomen, with their three external gills often acting as fins. Damselfly larvae are excellent hunters, acquiring their energy from tiny insects such as water fleas, which they catch using a detachable mouthpart of the lower jaw known as the labium. When in reach of its prey, the nymph rapidly extends its labium, and the unfortunate prey is pierced within a fraction of a second. Over a period of anywhere from a couple of months to 2-3 years, the nymph will moult around 12 times, with wing pads beginning to show in the later moults. When fully developed, the nymph climbs onto land, its thorax splits, and an imago (adult) damselfly emerges. Initially, the imago’s wings are small and limp, and its body is soft; its exoskeleton then hardens and its wings expand, rendering the damselfly capable of flight within a couple of hours, or less depending on the conditions. Although a newly emerged imago’s colouration may seem dull, its colours become more vivid over the first few days of its adult life.
As an adult, the damselfly’s primary job is to find a partner and mate via the characteristic copulation wheel, so the female can oviposit its fertilised eggs. This brings us back to the beginning of the cycle.
Copper demoiselles in a copulation wheel (mating).
White-legged damselflies in tandem - the female oviposits her eggs into the water.