Dragonflies are often seen gliding gracefully among aquatic vegetation, which may lead to the mistaken belief that they consume plant matter. However, these insects are not herbivores in any stage of their life cycle. Dragonflies are obligate carnivores, acting as predators throughout both their aquatic juvenile phase and their aerial adult phase. Their biology is specialized for tracking, intercepting, and consuming prey, and their diet consists entirely of other living creatures.
The Actual Diet of Adult Dragonflies
The adult dragonfly is an apex predator of the insect world, relying on speed and aerial agility to secure its food source. Their diet is composed almost exclusively of smaller flying insects, which they capture directly in the air. Common prey includes flies, mosquitoes, midges, gnats, and sometimes larger insects like butterflies, moths, and even smaller dragonflies.
Dragonflies are highly successful hunters, with some species achieving a hunting success rate as high as 97%. They accomplish this by using their long, spiny legs as a forward-facing basket or net to scoop prey out of the air while in flight. The dragonfly consumes the meal mid-flight, using its powerful, toothed mandibles to quickly immobilize and chew the prey. This strategy helps control populations of nuisance insects like mosquitoes and gnats.
Dragonflies possess enormous compound eyes that grant them nearly 360-degree vision, processing information rapidly to calculate a prey’s trajectory. They employ a sophisticated hunting technique that involves predicting the prey’s future position rather than simply chasing its current location. This precision, combined with their ability to hover, fly backward, and change direction instantly, makes them highly effective hunters.
The Role of Plants in a Dragonfly’s Life
While dragonflies do not eat plants, vegetation provides the structural foundation for their life cycle. Aquatic plants, such as reeds, rushes, and cattails, offer the vertical surface needed for the final stage of metamorphosis. The aquatic nymph must crawl out of the water onto a stem to shed its final skin and emerge as a winged adult.
Plants also serve as perching locations for adult dragonflies. They use these perches to rest, bask in the sun to regulate body temperature, and survey their territory for food and mates. A strategically chosen perch overlooking an insect-rich area improves hunting efficiency.
Plants are also utilized as the physical site for egg-laying, a process known as oviposition. Many female dragonflies insert their eggs directly into the tissue of submerged or emergent aquatic plants using a specialized appendage. The plant tissue provides protection and a stable environment for the developing eggs until they hatch.
What Dragonfly Nymphs Eat
The juvenile stage, known as a nymph or naiad, is fully aquatic and spends its life underwater, often for several years. Dragonfly nymphs are ambush predators, concealing themselves within the sediment or among aquatic vegetation to wait for unsuspecting prey. Their diet is diverse and includes a range of smaller aquatic creatures.
The nymphs feed on aquatic insect larvae, including mosquito larvae, as well as small worms, crustaceans, and even tiny fish or tadpoles. They possess a lower lip called a labium, which is folded under the head like a mask when at rest. When prey comes within striking distance, the labium shoots out rapidly, grasping the victim with terminal hooks before retracting it back to the mouth.