Dragonflies Aren't Pests
Regardless of their fearsome appearance, dragonflies do not sting, and they are completely harmless to people. Dragonflies consume 10 percent to 15 percent of their weight per day on insects such as mosquitoes, termites, deerflies, blackflies, horseflies and midges. They make welcome residents in the yard. Think of them as the insect equivalent of getting a cat to solve your mouse problem. If you want to attract dragonflies to your yard, the best lure is a body of water. Good news for pond owners! Dragonflies lay eggs in or near water, where their young hatch and develop into nymphs. They live underwater for months before emerging as adults. But even as nymphs, they are voracious eaters, happily dining on mosquito larvae and other underwater creatures.
To bring in dragonflies, put plants in and around the pond. Plants, both submerged and floating, add oxygen to the water and remove carbon dioxide. They provide hiding and resting places for nymphs and are used as incubation chambers, because some species insert their eggs into the soft stems. Tall plants that stick out of the water provide places for adult dragonflies to perch and scan for food or mates. They also allow a place for the nymphs to climb up to undergo their transformation process from nymph to adult. Dragonflies come in many brilliant colors -- copper, emerald, amethyst, sapphire and others.
Their lives impact both water and land ecosystems. Once hatched, dragonfly nymphs are able to breathe underwater, and they use a motion similar to jet propulsion to move through their environment. This enables them to eat harmful aquatic organisms such as mosquito larvae. The nymph will continue contributing to the ecosystem for one to five years before becoming a mature adult. The adult dragonfly has huge compound eyes that are useful in searching for flying insects. While flying it uses its six legs to scoop food out of the air. Clasping the prey in its front legs, it then eats the insect in flight. Dragonflies play ecological roles not only as predators but also as prey of birds, frogs and other creatures.
The presence of dragonflies indicates fresh water. So not only should you leave them alone when they arrive, when they do it’s a good sign your pond is healthy! In fact, national parks often use this species to survey and document the health of the park's water ecosystems. Since dragonflies eat mosquitoes and other insects, they help gardeners and outdoor enthusiasts. This also helps the environment since the use of pesticides to kill these insects can be reduced. Dragonflies are simply beneficial. Attracting dragonflies to your yard helps protect these bug-zappers while cutting down on the bugs that really bug you.