The life cycle of dragonflies and damselflies is both complex and fascinating. Odonata pass through three distinct stages: egg, aquatic larva, and aerial adult. Although we most often notice them as dazzling flying insects, the majority of their lives is spent hidden underwater in rivers, lakes, and ponds.
After mating, the female lays eggs (a process known as ovipositing) directly into or very close to water. There is no internal gestation; fertilised eggs are deposited immediately after copulation.
Eggs are tiny – typically between 0.5 mm and 1.5 mm. Egg shape varies depending on the ovipositing method:
A single female may lay hundreds or even thousands of eggs at a time. Most hatch within a month, but some species’ eggs overwinter and hatch the following spring, especially those laid late in the season.
When the egg hatches, a larva emerges. Odonata larvae share some features in common with the adult form, with compound eyes, six segmented legs, and developing (but non‑functional) wings. Unlike adults, they do not breathe air; instead, they rely on gills for oxygen.
The larval stage consists of multiple moults, culminating in the final transformation into the flying adult (the imago). Dragonflies and damselflies are hemimetabolous insects, meaning they undergo incomplete metamorphosis – there is no pupal stage as seen in butterflies or flies.
Larvae spend far longer underwater than adults spend in the air. This stage lasts months or even years, depending on species. They are sexually immature and devote their lives to hunting and feeding. Dragonfly larvae in particular are formidable predators and will eat almost anything smaller than themselves.
Once a dragonfly or damselfly emerges from the water and takes flight, it becomes an agile and efficient predator of other insects. Adults feed exclusively on live prey; they do not eat carrion or vegetation. Their primary biological purpose, however, is reproduction.
Odonata mating behaviour is unique, and some species engage in intricate courtship displays. Male dragonflies are often highly territorial and will aggressively chase away rivals, even of different species. This behaviour is less pronounced in damselflies, though very noticeable in demoiselles.
Adult lifespans are short compared to the larval stage:
Unlike larvae, adults do not grow or moult – they are fully formed from the moment they take flight.