Dragonflies are fascinating insects that have been around for over 300 million years. They are known for their large, colorful wings and their ability to fly quickly and change directions abruptly. Dragonflies do not sting or bite, but they are formidable predators that catch and eat other insects while flying. Here is a closer look at dragonflies and whether they pose any risk to humans through stinging or biting.
Do Dragonflies Have a Stinger?
Dragonflies do not have a stinger. Only certain insects like bees, wasps, and ants have stingers. The stinger is a modified egg-laying device (ovipositor) that has evolved into a weapon of defense. When threatened, bees, wasps, and ants can quickly jab their stingers into skin and inject venom.
Dragonflies do not have this ability. They have an ovipositor but it is only used for laying eggs in water or on aquatic plants. The ovipositor cannot penetrate human skin like a stinger can. Dragonflies do not produce any venom either. So they simply do not have the physical capacity to sting people.
Do Dragonflies Bite Humans?
Dragonflies also lack the mouthparts needed to deliver painful or venomous bites. Dragonflies have chewing mouthparts designed for catching and eating other insects. Their jaws are not made for biting into human skin.
The mouth of a dragonfly does not open very wide either. Their prey is typically quite small, like mosquitos and flies. Dragonflies simply cannot generate enough force with their mouthparts to bite through human skin. There are no documented cases of dragonflies biting people.
So while dragonflies may startle you by flying close to your head, they cannot physically sting or bite you. Their mouthparts are strictly for catching other flying insects, not humans.
Why Dragonflies Get Close to People
Dragonflies will sometimes land on people or buzz around very close to your head. This does not mean they are trying to sting or bite. From a dragonfly’s perspective, humans are just tall structures that provide a convenient perch while hunting.
Dragonflies are visual hunters, so they may land on humans to get a elevated vantage point to spot prey. The motion of people walking or working outdoors also mimics the movement of prey. This can draw curious dragonflies in close to investigate. But rest assured, they have no interest in biting you.
Dragonflies may also land on people briefly to warm up their flight muscles. Being cold-blooded, dragonflies need to raise their body temperature in order to fly and hunt effectively. Perching in the sun allows them to warm up. The human body gives off heat that dragonflies can absorb to reach their optimal temperature more quickly.
So while having a dragonfly land on your arm or zip around your head can be startling, the dragonfly is just exhibiting its natural hunting and basking behaviors. It does not equate to aggression towards people on the dragonfly’s part.
Are Dragonfly Mouthparts Dangerous?
While dragonflies cannot bite hard enough to break human skin, their mouthparts are incredibly effective at catching and eating other insects. Their jaws are strong enough to crush prey and down it in midair.
Here are some key facts about dragonfly mouthparts:
- Their lower jaw extends out into a powerful, toothed labium that can rapidly dart out to capture prey.
- The labium has hooks and bristles that latch onto victims and pull them back to the jaws.
- Powerful jaws (mandibles) crush prey and move side-to-side to mash food into a swallowable form.
- Their mouth can open up to 180 degrees to consume large prey.
- Saliva helps liquefy prey for easier digestion.
So dragonfly mouthparts are well-suited for catching and eating other flying insects of a suitable size. Their jaws allow them to efficiently consume mosquitos, flies, moths, butterflies, and even smaller dragonflies at times.
How Dragonflies Hunt and Eat Prey
Watching a dragonfly capture and consume its prey is a remarkable process:
- The dragonfly spots prey while flying and glides into pursuit.
- When close enough, the labium shoots out and grabs the victim.
- The prey is pinched between the labium and jaws as the dragonfly continues flying.
- Powerful mandibles mash and crush the prey.
- Bits of prey are manipulated and oriented for swallowing.
- The crushed food gets swallowed and passes into the digestive system.
Dragonflies are able to capture and eat prey at high speed and while flying in multiple directions. Their large, hemispherical eyes contain up to 30,000 individual lenses, giving them incredible visual acuity. Their four wings can beat independently, allowing for precision aerial maneuvers.
Dragonflies will consume up to hundreds of insects per day. Mosquitos make up a substantial portion of many dragonfly species’ diets.
Would a Dragonfly Bite Feel Painful?
As mentioned earlier, dragonflies lack the mouthparts needed to bite into human skin. But if they could, would a dragonfly bite feel painful?
Since they eat small soft-bodied insects, dragonfly jaws are not designed to deliver an excessively painful bite. Their jaws would likely feel pinchy on bare skin. However, they do not have any venom and their saliva does not contain substances irritating to humans.
Overall, the notion of a dragonfly bite is more hype than fact. In reality, they do no harm to people even when landing on your arm or buzzing around your head.
Do Dragonfly Nymphs Bite?
Dragonfly nymphs, also called naiads, are the juvenile stage before adulthood. Nymphs live underwater and prey on small aquatic animals like mosquito larvae. They have the same chewing mouthparts as adults, specialized for catching small prey.
In rare cases, a dragonfly nymph might nip your finger if you picked one up to examine it. But their jaws are not strong enough to break through human skin. There are no substantiated reports of dragonfly nymphs biting people.
Nymphs do not pose any danger to humans swimming or wading either. They prefer to stay hidden among underwater plants and debris, only darting out to ambush prey that swims by their hiding spot. They are not aggressive and do not go after large animals.
Conclusion
Dragonflies are predaceous insects that adeptly catch other flying insects for food. While they look fierce as they hunt, dragonflies do not sting or bite humans. Their legs lack stingers, and their jaws cannot generate enough force to break human skin.
Dragonflies may land on people while hunting or basking, but they exhibit no aggression or inclination to bite. Their mouthparts strictly serve to catch small insect prey, not large animals. So while startling when they zip around your head, dragonflies are harmless to humans. Their presence around water indicates a healthy ecosystem, so they should be welcomed as interesting and beneficial insects.
