Maryland Grows

Dragonflies are amazing insects. Their aerial acrobatics are impressive as is their ability to control pests from mosquitoes to biting flies.

And oh their beauty when shimmering over a garden or pond! Over 5,000 species dress themselves in everything from basic black to electric blue, tasteful stripes to Rorschach ink blots.

Dragonflies first cruised the skies 300 million years ago with 2-foot wingspans. They were among our first winged insects.

Since then they’ve perfected their flying skills. They can move up, down, sideways and backwards, hover and reach speeds of 30 miles per hour. One species migrates 11,000 miles including an ocean crossing.

Several evolutionary adaptations make dragonflies exceptional hunters.

Their head is almost all eyes with over 30,000 facets, allowing them to see nearly 360 degrees. Each of their 4 wings is controlled independently, giving them enviable maneuvering abilities.

Dragonflies and their damselfly cousins comprise the insect order Odonata meaning “toothed ones.”  Watch them hunt and you’ll understand why.

They grab prey in flight using spines on their long legs. Then they use their serrated mandibles to tear them apart and eat them, often while flying. It’s the original dinner to go.

Dragonflies can zero in on one insect in a swarm and follow it with uncanny accuracy thanks to a neural bundle that connects with a flight center in their thorax. They make minute adjustments and – bam – it’s over before that bug knew what hit it.

A Harvard University study showed that dragonflies successfully capture 90 to 95 percent of the prey they pursue.

Mosquitoes, flies, gnats, aphids, bees and other insects may be on the menu. While dragonflies are generalists, they help to control pests and can eat hundreds of mosquitoes a day.

A dragonfly’s life starts in the water. A male dragonfly patrols pond edges looking for food and friendship. When he finds a receptive female, they connect in a heart-shaped flying configuration known as a “mating wheel.”

Is anyone else hearing the theme song from “The Dating Game?”

The female lays her eggs on the water or aquatic plants. They hatch in about a week, becoming aquatic nymphs or naiads.

Juvenile dragonflies are as voracious as adults, eating mosquito and other insect larvae, crustaceans, tadpoles, fish, and even other dragonfly young.

Nymphs plod along until dinnertime. Then they blast water through their abdomens to become jet propelled. An extendable jaw snaps forward like a frog’s tongue and nabs unsuspecting prey.

Naiads molt many times during their 2 or more years underwater. Then they crawl out of the water onto a plant or stone and split out of their skin to emerge as adult dragonflies.

Dragonflies need clean water and stable oxygen levels, making them good indicators of a healthy ecosystem. Everything we do to help keep our waterways clean helps dragonflies.

To do more, add a pond or water feature to your landscape. Include some clear surface area and varied plants in and out of the water. Dragonflies will return the favor with natural pest control and beauty on the wing.

By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension. This article was previously published by Herald-Mail Media. Read more by Annette.