Green Darner Dragonfly an Amazing Acrobat
On a hot and humid July night, I stood gazing out over a friend’s three-acre horse pasture abutting the Natchaug River when I witnessed a sight I had only ever heard about. In the lower pasture I noticed a dragonfly air force squadron patrolling the airways.
Dozens of them darted left then right, hovered in mid-air, then flew straight up and zipped off in a dizzying aerial display. I was witnessing a green darner dragonfly feeding frenzy with aeronautical maneuvers no man-made plane, jet or helicopter could match. Back and forth they zoomed, devouring mosquitoes and any other hapless flying insects caught in their sights.
I have seen these multi-colored, large dragonflies before, and always marveled at their size, speed, and colorful bodies. I had never seen a swarm of them gathered together before, so I did some research about the amazing green darner dragonfly.
In New England, we have at least 20 species of the darner dragonfly. The green darner, also sometimes called common green darner (Anax Junius), is the largest and most frequently seen. They get their name due to their long abdomen, which resembles a darning needle.
The green darner has huge eyes that meet on the top of its head, and its abdomen is long and narrow with a dark line down the center of the dorsal surface. Adult males show contrast between the bright green thorax and bright blue thorax. Females and younger males are duller but show the same blue and black bulls-eye marking on their frons, or forehead, as the male.
Dragonflies were some of the first winged insects to evolve some 300 million years ago. The green darner is our largest in New England, with the adult length and wingspan being approximately three inches. Just imagine, dragonfly fossils have been found with wingspans of up to two feet.
The flying display I witnessed on that hot July day is typical of dragonflies, with a flight pattern of straight up and down and hovering like a helicopter. Their speeds are very fast and have been clocked at 35 miles per hour.
In both the larva and adult stage, green darner dragonflies are predators. The adult catches its prey during flight by grabbing it with its feet and devouring it while still flying. All flying insects — from mosquitoes to bees, butterflies and beetles to even smaller dragonflies — are prey to this hunter of the skies.
All dragonflies go through metamorphosis in three stages of egg, nymph (larva) and adult. The female dragonfly deposits her eggs on floating or waterside aquatic vegetation. She’ll make a slit in a stem or leaf and place the egg inside it to help protect the egg until it hatches. The male will hover above her or clasp her while flying in tandem, and if she submerges to deposit eggs, the male may help to pull her out of the water. A clutch of eggs can number as many as 1,500 and take about a week to hatch.
The aquatic nymph matures in the water for up to two years, molting several times. It will eat just about anything, including mosquito larva and even fish and tadpoles. When ready to metamorphose into an adult, the nymph will go to the surface, usually at night, and remain stationary with its head out of the water while its respiration system adapts to breathing air. It will then climb vegetation until above the water’s surface and molt one last time to emerge as an adult. Its exoskeleton cracks open and releases the insect’s abdomen, which had been packed in like a telescope and upon emerging expands to its adult length. Its four wings come out, and they dry and harden over the next several hours and days. The adult usually lives for only a few weeks.
Almost all of the dragonfly head is covered by its two eyes, and it has incredible vision that encompasses every angle except right behind it. Along with exceptional flying skills, a dragonfly’s eyesight and field of vision make it a superior hunter of the sky.
This is the time of year when the adult green darner dragonflies can be seen in large swarms. They are amazing flying acrobats and to witness their skill in hunting is always a thrill. The added benefit is all the mosquitoes they eat.
I hope you’ll join me as we look to nature each and every day for information and inspiration. We are lucky to live in a National Heritage Corridor rich in cultural and natural resources. Together we can care for, enjoy, and pass on this special place called The Last Green Valley.
Sources for this column include the Smithsonianmag.com, Kaufman Field Guide to Nature of New England, World Animal Foundation website, and the website ThoughCo.com
Bill Reid is chief ranger of The Last Green Valley National Heritage Corridor and has lived in the region for more than 35 years. He can be reached at email@example.com.
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