Dragonfly Nymph

Dragonfly nymphs, also called naiads, are the aquatic immature stage of dragonflies in the suborder Anisoptera. Unlike the brightly colored, fast-flying adults, nymphs are drab, robust, and entirely aquatic, spending the majority of a dragonfly's life cycle hidden among submerged vegetation or debris on the bottom of ponds and streams.

Nymphs are equipped with a highly specialized hinged lower lip called a labium, which can shoot forward in a fraction of a second to grasp prey, a feature they share with damselfly nymphs. Dragonfly nymphs are generally stockier and broader-bodied than the more slender damselfly nymphs, and they breathe using internal gills located within the rectum rather than external gill filaments.

Depending on the species and local climate, the nymphal stage can last anywhere from a few months to several years, making it by far the longest phase of a dragonfly's life, with the winged adult stage lasting only weeks to a few months by comparison.

• Nymphs are 15-50 mm long depending on species, with a stout, somewhat flattened body and six sprawling legs.
• Coloring is typically mottled brown, olive, or gray, providing camouflage against pond sediment and debris.
• No external tail gills are present, distinguishing them from damselfly nymphs; instead, gills are internal.
• Large eyes and a hinged, extendable labium (lower lip) folded beneath the head are diagnostic features used to capture prey.
• Wing pads become more visible on the back as the nymph approaches its final instars.
• Lookalikes include damselfly nymphs, which are more slender with three feathery external gills projecting from the tip of the abdomen.

Dragonfly nymphs are found in freshwater habitats worldwide, including ponds, lakes, marshes, and slow-moving sections of streams and rivers. They typically live among submerged vegetation, leaf litter, or bottom sediment, where their camouflage helps them ambush prey. Nymphs can be found year-round in permanent water bodies, with emergence of adults concentrated in spring and summer in temperate regions.

Dragonfly nymphs are ambush predators, lying motionless until prey comes within range and then striking with their extendable labium, which shoots forward to seize the target and draw it back to the mandibles. They feed on a wide range of aquatic invertebrates, small fish, and tadpoles, making them significant predators within pond and stream food webs. Nymphs breathe by drawing water into the rectum, where internal gills extract oxygen, and some species can even expel this water forcefully to jet-propel themselves away from danger. As both predator and prey, nymphs are consumed by fish, other larger nymphs, birds, and amphibians, linking them to multiple levels of the aquatic food web.

Eggs are laid in or near water, either inserted into plant tissue or scattered directly into the water depending on species. Nymphs hatch and undergo gradual metamorphosis through numerous instars, molting repeatedly as they grow over a period ranging from several months to a few years. In the final instar, the nymph climbs out of the water onto emergent vegetation or a rock, where its skin splits and the winged adult dragonfly emerges and expands its wings before flying off. Most temperate species overwinter as nymphs underwater, with only the adult stage occurring above the water's surface.