The dragonfly, an ancient insect belonging to the order Odonata, is a large, fast-flying creature frequently observed near water sources. Its size and rapid flight often lead people to question whether it poses a danger to humans. These aerial acrobats are skilled predators, but misconceptions exist about their intent toward people. Examining their behavior and anatomy clarifies their true nature.
Are Dragonflies a Threat to People?
Dragonflies are not aggressive toward people and lack the instinct to attack large mammals. Their existence revolves around hunting smaller, flying insect prey, defending territory, and mating. When a dragonfly appears to “dart” at a person, it is almost always pursuing a small insect, such as a gnat or mosquito, flying nearby. They do not view humans as a food source or a threat.
The rapid, erratic movements that seem confrontational are simply a display of their flight agility while hunting. An adult dragonfly is more likely to land momentarily on a person as a perch than to attempt aggression. Their disposition toward humans is indifference, only engaging when defending territory or when constrained.
Anatomy and the Possibility of Biting
The fear of being stung by a dragonfly is unfounded, as these insects physically lack a stinger. The long, slender abdomen, often mistaken for a stinging apparatus, contains no venom or sting capability. They do, however, possess strong mandibles, or jaws, used to capture and consume prey.
A dragonfly will only use these mandibles on a human as a last resort, purely in self-defense if it is roughly handled or squeezed. For most species, the mandibles are not strong enough to pierce human skin, resulting in a harmless, minor pinch. Only the largest species, such as some darners, may lightly break the skin, but even this rare defensive action is not dangerous.
Their True Role as Aerial Predators
Dragonflies are successful insect predators, recognized for a hunting success rate approaching 97%. They primarily target small, soft-bodied flying insects, including gnats, smaller flies, midges, and especially mosquitoes. A single dragonfly can consume hundreds of these pests daily, making their presence highly beneficial to humans.
They hunt using a unique strategy, catching prey mid-flight with their six spiny legs, which form a “basket” or net. The captured meal is often consumed immediately, without the need to land. Their ability to fly in six directions allows them to outmaneuver virtually any other insect in the air. Acute vision, provided by massive, multifaceted compound eyes, helps them track and intercept prey with precision.
Why People Believe They Attack
The belief that dragonflies are aggressive stems largely from historical folklore and misleading common names. Many European and American cultures once referred to the insects as the “Devil’s Darning Needle” or the “Horse Stinger.” These names originated from the insect’s needle-like appearance and its habit of flying around livestock.
The term “Horse Stinger” was coined because people mistakenly believed the dragonfly was stinging horses, which were actually being bitten by horse flies that the dragonfly was hunting. Similarly, “Devil’s Darning Needle” originated from a superstition that the insect would sew up the eyes or ears of misbehaving children. These myths, not biological fact, are the primary reason the dragonfly has developed a false reputation for being a threat.