Dragonflies are ancient, highly effective predators that have patrolled the skies for hundreds of millions of years. Their incredible speed and aerial maneuverability establish them as apex hunters in the insect world. These insects play a significant role in ecosystems, primarily by controlling populations of smaller flying pests. Their life cycle involves two distinct predatory phases, one in the air and one in the water, each with a specialized hunting strategy.
The Direct Answer: Do Dragonflies Eat Spiders?
Adult dragonflies do not typically seek out spiders as a regular part of their diet. Their hunting strategy focuses on capturing prey mid-flight, making terrestrial spiders generally inaccessible. However, dragonflies are opportunistic carnivores and will consume any arthropod they can successfully capture.
Spiders become a meal primarily through aerial or web encounters. A spider ballooning on a silk strand, or one snatched from a web, may be consumed. Adult dragonflies have also been observed hovering near and plucking spiders directly out of their webs. This behavior demonstrates that spiders are on the menu if the chance presents itself.
Primary Diet and Hunting Strategy of Adult Dragonflies
The daily diet of adult dragonflies consists almost entirely of other flying insects. Their preferred prey includes soft-bodied, abundant fliers like mosquitoes, midges, gnats, and various types of flies. Larger species also regularly prey on moths, butterflies, bees, wasps, and even other smaller dragonflies.
Dragonflies are masterful aerial hunters, relying on exceptional vision and agility to spot and intercept targets. Their compound eyes grant them an almost 360-degree field of view, allowing them to calculate a prey’s trajectory precisely. They do not chase prey but calculate the insect’s future position, flying a course to intercept it.
The capture mechanism involves a specialized use of their six spine-covered legs. In flight, a dragonfly maneuvers its legs forward to form a cage or “basket.” They scoop the prey into this basket and immediately transfer it to their mandibles, often consuming the meal without landing. This continuous feeding allows larger individuals to consume their own body weight in prey every day.
The Aquatic Hunter: Dragonfly Nymph Diet
Before taking to the air, the dragonfly spends months or even years underwater as an aquatic nymph, or naiad. These nymphs are ambush predators that lie in wait among sediment and aquatic vegetation. Their prey includes a wide range of aquatic organisms:
- Insect larvae
- Worms
- Small crustaceans
- Vertebrates like tadpoles and small fish
Nymphs are equipped with a unique, hinged lower lip called a labium, sometimes referred to as a mask. This structure is folded beneath the head when at rest, but it can be rapidly extended to seize a victim. The labium is tipped with hooks or pincers to grasp the prey, and the strike is incredibly fast.
The nymph’s diet is important for its development, and they are not selective, often eating anything smaller than themselves they can subdue. This includes mosquito larvae, which nymphs consume in large quantities before they emerge as flying adults. Some aquatic spiders, if present in the same habitat, may also fall victim to the sudden strike of a dragonfly nymph.