How do dragonflies eat? Explore dragonflies life cycle and fantasies behind these fascinating insects, and learn how to attract dragonflies to eat mosquitoes.
Dragonflies capture our attention and imagination, their gossamer wings rattling and flashing in the sun as they patrol the water’s edge or hover above grassy fields. They’ve been surrounded by myth and superstition for as long as our eyes have followed their flight. But the truth of what they can do is even more amazing than what we can dream up, and once you’ve learned about them, you’ll want them to make your backyard their lair.
Fantastical Flyers
Much like their mythical namesake, dragonflies inspire equal parts terror and wonder, the terror entirely unjustified – unless you’re a flying insect, of course – and the wonder well-deserved.
These creatures have been accused of stinging horses to death and nursing serpents back to life. Naughty children napping outside would fear waking to find their eyes sewn shut by the “devil’s darning needle”; likewise, gossips, liars, and users of coarse language would supposedly risk having their mouths sewn shut. Even fishermen have a beef with these insects, accusing them of driving the fish away from the hooks of anglers they deemed unworthy. On the other hand, dragonflies supposedly draw fish to the lines of the good-at-heart.
In Japan, dragonflies are said to serve as steeds for the spirits of the honored ancestors returning to visit their descendants during the Obon festival each August. Elsewhere, they’re considered to be spiritual messengers or a sign of good fortune. Swarms of dragonflies are believed to indicate approaching rain or good fishing. What’s a fisherman to do?
Even their name is wrapped up in superstition and myth. “Dragon” refers not to the massive fire-breathing reptiles of fantasy novels and role-playing games, but to the dragon, Satan himself. According to Northern European lore, the Devil uses dragonflies as his personal steeds, so the dragon flies.
Specific groups and species of dragonflies have many colorful common names evoking their supposed abilities: snake doctor, snake charmer, mule stinger, horse-sting, cow killer, ear cutter, darner. Other names are fanciful as well as evocative: mosquitohawks, meadowhawks, bog hunters, pondhawks, sanddragons. My personal favorite? The Stygian shadowdragon.
How Do Dragonflies Eat?
Dragonflies are an ancient group of insects, sharing the order Odonata (meaning “toothed”) with the more diminutive damselflies. Both groups are predatory, feeding on small creatures within their reach as young aquatic nymphs (typically called “naiads”), and feeding on small flying insects as adults.
The naiads will spend up to five years in the water, feeding on other insects, tadpoles, and small fish. They have an incredible (some would say nightmarish) adaptation for catching their next meal. A dragonfly naiad’s lower jaw has a retractable double hinge, allowing it to fold back under its chin. When a target gets too close to the heavily camouflaged naiad, the naiad can shoot that extendable jaw forward in a blur, snagging the prey and dragging it back to its mouth in the blink of an eye.
Dragonflies Life Cycle
Once the naiads have grown, they’ll crawl above the water’s surface onto a stem or other structure, where they’ll shed their skin for the final time and gain wings and an adult form. Adult dragonflies will never walk again; from this point on, their legs are strictly for perching and snagging prey. For the next several weeks to months, they’ll become masters of the air. While some species migrate, most spend their short time in the summer sun before leaving their offspring to spend winter underwater as eggs or naiads.
The largest dragonfly in North America is the aptly named giant darner, with a hand-spanning 5-inch wingspan and a length to match. The smallest dragonfly on the continent is the diminutive elfin skimmer, reaching barely 3/4 inch in length.
About 7,000 Odonates exist worldwide, on every continent except Antarctica, and 3,000 of them dragonflies. North America hosts more than 450 dragonfly species and almost as many damselflies.
Damselfly vs Dragonfly
How do you tell the difference between dragons and damsels? In general, damselflies are smaller and daintier, as their name implies. Where dragonfly hind wings are larger than their forewings and are typically outstretched at rest, damselfly wings are all the same size and are usually folded together above or behind the back at rest. A damselfly’s head is also different; where a dragonfly head is practically all eye and mouth, with the eyes touching in the middle, a damselfly’s eyes are smaller and wideset and separated by a broad “forehead.” The biggest difference, however, is that dragonflies are powerful aerial acrobats, while damselflies have to make do with a weaker, fluttery flight.
Beyond that, they share the same basic body layout of a head, a muscular thorax, and a long, narrow abdomen, which, for the record, doesn’t contain a stinger. The thorax sports four wings and six legs. Their legs are perfectly designed for grabbing on to prey and perches, not for taking a stroll. That means these dragons do just about everything on the wing: hunting, eating, fighting, mating, and, often, laying eggs. While some species will spend time perching on vantage points to watch for meals, mates, or rivals, others spend nearly every waking moment aloft.
Not much escapes a dragonfly’s notice. Its massive eyes provide a near-360-degree field of view. Its only blind spot is the area directly behind it. Yes, it’s nearly impossible to sneak up on a dragonfly.
Dragonflies pair this incredible field of vision with an equally impressive set of flight skills. They can hover and fly vertically, side to side, and backward, and they can even turn somersaults at speed. Dragonflies have been reliably clocked at 35 mph.
What Do Dragonflies Eat?
With this combination of superior vision and aeronautics, dragonflies are ideally suited for snagging their meals on the wing. No flying insect is safe from a hungry dragonfly. A single dragonfly is said to consume anywhere from 30 to more than 100 mosquitoes in a day, earning it the nickname “mosquitohawk.” One Harvard University study titled “Capture Success and Efficiency of Dragonflies Pursuing Different Types of Prey” found that dragonflies are so effective as aerial hunters that test subjects caught up to 95 percent of the prey released into their enclosures.
Just as dragonflies eat, they’re also eaten. Fish, amphibians, and other aquatic predators will prey on naiads, just as naiads prey on smaller creatures. Adult dragonflies also find themselves feeding fish, frogs, reptiles, birds, and bats. They provide an important link in the food web between small flying insects and larger predators.
How to Attract Dragonflies to Eat Mosquitoes
By now, you’re probably thinking you might want to invite dragonflies to your next lawn party to manage the mosquitoes. And you can! All you have to do is supply them with a few amenities.
The best way to invite dragonflies (and damselflies) to your yard is to install a water feature, such as a pond garden, or to make use of an existing stream or stock pond. Lay out the pond garden with shallow areas and deeper water, at least 2 or 3 feet deep. Plant your pond with submerged vegetation to create habitat for the naiads. Eelgrass, pondweeds, anacharis, and fanwort are all good candidates. Include emergent plants, such as water lilies, water lotus, arrowhead, water iris, and cattails, for perches and places for emerging naiads to cling to as they shed their skins and get their wings.
Consider stocking your pond with small fish, such as minnows or, in warmer climates, mosquitofish, to help avoid growing your own mosquito crop. The naiads will help consume mosquito larvae. Your pond will also soon harbor frogs and toads, which will help control mosquito larvae – and feed dragonfly naiads. Do skip the larger fish, as they won’t think twice about snacking on your future dragons. If you’re still worried about homegrown mosquitoes, consider adding mosquito dunks (Bacillus thuringiensis israelii, or Bti) to the pond water; these will control mosquitoes without affecting other aquatic insects. Add some flat rocks or bare, sandy banks for the dragonflies to bask in the warm sun; they need that solar energy to get going, especially on chilly mornings.
If you can’t add a pond, plant pampas grasses and shrubs for perches and pollinator plants to attract small flying insects that won’t disturb your backyard soirées. Pollinator favorites include black-eyed Susans and purple coneflowers, Joe Pye weed, swamp milkweed, and meadow sage; skip the similar-looking but invasive purple loosestrife. You can also set bamboo stakes at strategic spots to provide surveillance points for hungry dragons.
Avoid using insecticides or other pesticides wherever possible. Most will hurt predator and prey equally, and most pest species breed and recover faster than predator species can. Yes, that means pesticides can allow even more pests to move into your yard!
Devote a corner of your backyard to the dragons of the field. Give them a safe, clean home and a vantage point to survey their domain. Not only will you get to enjoy their aerial acrobatics in a mosquito-free zone, but you’ll also have more pollinators, pest-eating frogs and toads, and other natural entertainers calling your backyard their home.
Andrew Weidman lives and writes in Lebanon, Pennsylvania, where he grew up. He spent many a summer day afield with his dog and his butterfly net, stalking dragonflies and other insects for his ever-growing collection. These days, he’s traded his net for a camera.
