Dragonflies (order Odonata) are recognized for their speed and vibrant colors, making them a fundamental part of the food web in many ecosystems. Their life cycle has two distinct phases: the majority of their existence is spent underwater as a nymph before emerging as a winged adult. This dual habitat exposes them to a diverse array of predators. Dragonflies are a significant link in both aquatic and terrestrial food chains, serving as both hunters and prey.
Aquatic Predators of the Nymph Stage
The most vulnerable phase of the dragonfly’s life is its time spent as an aquatic nymph, or naiad. Nymphs reside in the sediment and vegetation of ponds, lakes, and streams. Their camouflage and slow movements offer limited defense against larger aquatic organisms.
Various species of fish are the primary consumers of dragonfly nymphs, especially those that forage near the bottom, such as bass, bluegill, and trout. In managed fisheries or natural bodies of water with high fish density, the survival rate of the nymphs is notably lower. Amphibians also pose a threat, with newts, salamanders, and frogs preying on the slower-moving naiads.
Even within the insect community, nymphs face predation from larger, specialized aquatic hunters. Predaceous diving beetles and their larvae can easily overpower the nymphs. Large aquatic bugs, sometimes called “toe-biters,” also feed on the nymphs by ambushing them from cover. Furthermore, dragonfly nymphs are cannibalistic, with larger individuals readily consuming smaller ones.
Aerial Predators of Adult Dragonflies
Once the dragonfly emerges from the water, it must contend with a new set of aerial predators. Adult dragonflies are among the fastest insects, but their flight skills are often overcome by specialized avian hunters. Birds are the most significant threat, particularly those with acrobatic flying styles that allow them to catch insects mid-flight.
Fast-flying birds like swifts and swallows frequently target dragonflies, consuming them while on the wing during their constant foraging flights. Specialized raptors, such as the Eurasian Hobby, rely heavily on dragonflies as a seasonal food source, sometimes consuming dozens in a single day. Flycatchers and various species of kingfishers also take advantage of the dragonflies’ brief, winged lifespan.
The adult dragonfly is most susceptible to capture when its mobility is compromised, such as during mating, egg-laying, or resting. During mating or egg-laying, the pair presents a larger, slower target. Bats, which become active at dusk, also prey on them, using echolocation to locate the resting insects.
Invertebrate Hunters and Trappers
Beyond the larger vertebrates, several invertebrate species have evolved effective strategies to capture the adult dragonfly. These hunters rely on ambush, trapping, or brute strength to subdue prey. Spiders are a common threat, particularly the large orb-weaver species, whose strong, sticky silk webs entangle the dragonfly’s wings.
The praying mantis is a formidable terrestrial ambush predator that waits patiently on vegetation for a dragonfly to land or fly within striking distance. Using its raptorial forelegs, the mantis seizes the insect. Some predatory insects, like the large robber flies, are even capable of catching dragonflies in the air.
Robber flies are known for their speed and aggressive hunting behavior, often attacking insects larger than themselves, including other dragonflies. These invertebrate hunters demonstrate that the dragonfly remains a common food source across many ecological niches.