Dragonflies are insects known for their swift, acrobatic flights as adults. They are skilled aerial predators, often seen darting near water bodies. While their winged adult form is widely recognized, dragonflies spend the majority of their lives in an aquatic, immature stage, living hidden beneath the water’s surface. This life cycle involves a distinct larval form known as a nymph, which looks quite different from the adult. Most of a dragonfly’s life unfolds in this underwater phase, which can last from a few months to several years depending on the species and environmental conditions.
Appearance of Dragonfly Nymphs
Dragonfly nymphs, also called naiads, have a body plan distinct from adults, though they share large eyes and six legs. They typically have a stout body shape, which can vary from elongated to flattened and broad depending on the species. Their coloration usually consists of drab, camouflaged browns, greens, or grays, allowing them to blend with the aquatic environment. Their head features large, compound eyes that nearly cover it, providing excellent vision for hunting.
The nymphs have six strong legs with two claws, used for crawling among submerged vegetation or burrowing into sediment. A specialized mouthpart called the labium, or “mask,” is tucked under their head at rest, and this hinged, scoop-like lower jaw rapidly extends outward to capture prey with hooks or pincers at its tip, acting like a spring-loaded grappling arm. Unlike adult dragonflies, nymphs breathe through internal rectal gills, drawing water into and expelling it from their hind end. This respiration method also allows them to rapidly propel themselves through the water using jet propulsion. Dragonfly nymphs can range in size from ¼ inch to 2½ inches.
Where Dragonfly Nymphs Live
Dragonfly nymphs are aquatic, inhabiting various freshwater environments, including ponds, lakes, slow-moving rivers, streams, and even temporary puddles or wetlands. They are often found among aquatic vegetation, submerged tree roots, rocks, or debris at the bottom. Some species prefer still waters, while others thrive in flowing currents, with certain types burrowing into soft substrates and others climbing on plants.
These nymphs are ambush predators, resting on the substrate or submerged plants, waiting for prey. When a potential meal, such as insect larvae, small crustaceans, tadpoles, or small fish, comes into range, the nymph’s extendable labium shoots out to snatch it. Their presence often indicates good water quality, as many species are sensitive to pollution and require clean, oxygen-rich environments to thrive.
Distinguishing Dragonfly Nymphs
Differentiating dragonfly nymphs from other aquatic insects, particularly damselfly nymphs, involves observing physical characteristics. Dragonfly nymphs are generally stouter and have wider abdomens compared to the more slender and elongated bodies of damselfly nymphs. A primary distinguishing feature lies in their gills: dragonfly nymphs possess internal rectal gills. Damselfly nymphs are characterized by three distinct, leaf-like gills that protrude from the tip of their abdomen.
While both dragonfly and damselfly nymphs possess an extendable labium for capturing prey, body shape and gill structure are the most reliable indicators for identification. Other aquatic larvae, such as mayfly or stonefly nymphs, have different body forms. Mayfly nymphs, for example, often have seven pairs of gills along their abdomen and three long tails. Stonefly nymphs usually have two tails and lack gills on their abdomen, often with gill tufts near their legs.