Dragonflies belong to an order of insects known as Odonata, which means “toothed one” in Greek and refers to the dragonfly’s serrated teeth. Fossil records show that dragonflies have existed for over 300 million years. The earliest dragonflies were much larger than the ones we see today. Some species had wingspans of over three feet and were the largest insects known.
Modern dragonflies (thankfully) are less than five inches long with wingspans of about four inches. In their larval stage, which can last up to two years, dragonflies live entirely under water and eat just about anything tadpoles, mosquitoes, fish, other insect larvae, and even each other. At the end of the larval stage, the dragonfly crawls out of the water, then its exoskeleton cracks open and releases the insect’s abdomen, which had been packed in like a telescope. Its wings emerge and dry out over the next several hours.
Adult dragonflies have the biggest eyes in the insect world. They can see 360 degrees around them, so they are able spot prey in any direction without turning their heads. They have four gossamer wings that move independently of one another, so they can fly forward, backward, sideways, straight up, straight down, and hover in place. They easily outmaneuver their insect prey and catch them by grabbing them with their feet. Their favorite meal is mosquitos — a single dragonfly can eat over 100 mosquitoes each day — and they eat other annoying bugs, such as midges, moths, and flies. Unfortunately, they also eat butterflies.
If you want to have dragonflies nearby, build a pond. Dig it deep enough so the water won’t freeze solid in the winter and put in a few native plants. Dragonfly larvae need plants that grow entirely under water, and when they are ready to emerge as adults, they need plants with stems that poke up out of the water. Adult dragonflies like to perch on floating plants with leaves that rest on the water's surface. Do not put fish in your pond. They eat dragonfly larvae.