Do Dragonflies Bite or Sting? Why Dragonflies Are Harmless

Can dragonflies sting?

No. Dragonflies have no stinger at all. The long, slender abdomen that looks like a tail ends in a set of small appendages. In males these are claspers, used to hold the female behind the head during mating. They cannot pierce skin or inject anything.

Some females, including darners such as the common green darner and most damselflies, have an ovipositor, a blade-like egg-laying tool on the underside of the abdomen. They use it to cut small slits in plant stems and place their eggs inside. It is not connected to any venom gland and is not used for defense. Many other dragonflies, such as skimmers and darters, have no cutting ovipositor and simply drop their eggs into the water.

This makes dragonflies very different from bees and wasps, whose stinger is a modified ovipositor connected to a venom gland.

Do dragonflies bite people?

Dragonflies have strong, toothed mandibles for chewing insects. The scientific name of their order, Odonata, comes from the Greek word for tooth. But dragonflies use their jaws for eating, not for attacking large animals. A dragonfly flying around you is hunting small insects or patrolling its territory and has no interest in biting you.

A bite can happen only if you catch or hold a dragonfly. A frightened dragonfly may twist its head around and nip the finger that holds it. In small species this feels like a light pinch or nothing at all. Large darners and similar dragonflies can pinch more firmly, and in rare cases might slightly break the skin, but they are not venomous and cause no lasting harm.

The simplest way to avoid even a nip is not to handle dragonflies. Watching them from a short distance is also better for the insects, whose delicate wings are easily damaged.

Why do dragonflies fly close to people?

People often feel that dragonflies are “buzzing” them, especially near water. There are several harmless explanations:

• Hunting. People, horses and cattle attract clouds of midges, mosquitoes and flies. Dragonflies follow large animals to pick off these insects in flight.
• Territory. Male dragonflies patrol a stretch of shore and fly up to inspect anything that moves into it, from a rival male to a walker.
• Perching. Many dragonflies like a high, sunny perch with a clear view. A fingertip, a hat or a fishing rod can serve as well as a twig.

None of these behaviors is aggressive toward people. A dragonfly that lands on you is simply using you as a convenient perch.

Myths: devil’s darning needles and horse stingers

Dragonflies have collected many fearful folk names. In parts of Britain they were called horse stingers, from the belief that they stung horses. In reality they were probably hunting the flies that swarm around horses.

In North America, the name devil’s darning needle comes from an old story told to children that a dragonfly would sew up the lips, eyes or ears of anyone who lied, cursed or fell asleep outdoors. It has no basis in fact. The name darner, still used for the large dragonflies of the family Aeshnidae, comes from the long, needle-like shape of the abdomen.

Other folk names are friendlier. In the southern United States, dragonflies are sometimes called snake doctors or mosquito hawks. In Japan they have long been admired as symbols of strength, courage and summer, and an old poetic name for Japan, Akitsushima, is often translated as “dragonfly island”.

Are dragonflies dangerous in any way?

Dragonflies are among the most harmless insects for people. They do not carry diseases to humans, do not damage homes or crops, and do not sting. Large swarms of migrating dragonflies, such as those of the green darner in fall, can look dramatic but pose no risk at all.

The only danger is to the insects they eat. Adult dragonflies are expert aerial hunters, and their nymphs are fierce underwater predators. Read more in what do dragonflies eat?

Dragonflies and damselflies: are either harmful?

Damselflies, the smaller, slimmer relatives of dragonflies in the same order, are even less able to bite than dragonflies. Both groups lack stingers and venom. Females of most damselflies have an ovipositor for placing eggs in plants, which is equally harmless. To tell the two groups apart, see dragonfly vs damselfly.

If you are worried about a bite or sting from an insect, the more likely culprits are wasps, bees, horseflies or mosquitoes, not dragonflies. Anyone who has a severe reaction to any insect sting, such as trouble breathing or swelling of the face, should seek emergency medical help immediately: call 911 in the US, 112 in the EU or 999 in the UK.