Dragonflies are common insects often seen near water. Their swift movements sometimes lead people to wonder if they pose a threat, particularly regarding biting or stinging. This article clarifies their interactions with humans.
Dragonfly Mouthparts and Biting
Dragonflies possess mandibles, jaw-like mouthparts used for biting. These are primarily used for capturing and consuming prey, such as mosquitoes and flies. Their insect order, Odonata, translates to “toothed one,” referencing these serrated mouthparts. Dragonflies are efficient aerial predators, often catching prey mid-flight before consuming it.
While dragonflies can bite, instances involving humans are rare and harmless. A dragonfly might bite in self-defense if caught or handled roughly. Even when they bite, their mandibles are too weak to break human skin, though larger species might cause a slight nip or minor scratch. These bites are not venomous, meaning no toxic substance is injected, and any discomfort is minimal.
Dragonfly Anatomy and Stinging
Dragonflies do not have a stinger. Unlike insects such as bees or wasps, which use a modified ovipositor (egg-laying tube) for defense and venom delivery, dragonflies lack the anatomical structures necessary to sting. Their long, slender abdomen, which some might mistake for a stinger, serves various functions, including reproduction and flight stability.
Female dragonflies have an ovipositor, solely for laying eggs. Depending on the species, this organ deposits eggs in or on water, or punctures soft plant tissues to insert eggs. This ovipositor is not equipped to deliver venom or inflict a sting on humans. Therefore, despite old folk names like “horse-stinger,” dragonflies are incapable of stinging.
Interactions with Humans
Dragonflies are harmless to humans. Their primary defense relies on speed and agility, allowing them to evade threats rather than engage in confrontation. They are master flyers, capable of darting away quickly when they sense danger.
They provide benefits to ecosystems and humans. Dragonflies are effective predators of pest insects, including mosquitoes, flies, and gnats. A single dragonfly can consume hundreds of mosquitoes daily, playing an important role in controlling mosquito populations and reducing the spread of mosquito-borne diseases. Dragonflies might occasionally land on humans, viewing them as a resting spot or being drawn to smaller insects. Such encounters are benign and pose no threat.