Thursday, August 17, 2017  

Just Gardens: 12th Annual Garden Tour to Benefit Haven Shelter and Services


“Creatures of the sunlight that pirouette on sparkling wings in plain view of all who take the time to look, dragonflies are nonetheless among the most elusive of insects. Few people take the time to get a close look at these ever-vigilant aerial predators, and fewer still know what they are seeing. Interaction with dragonflies can be entertaining and rewarding. It can also be used to catch the interest of children and increase their appreciation for these delightful insects.”

Insects are in vogue today. Some of our favorite summer residents—bees, ladybugs, butterflies, and dragonflies—are everywhere, appearing on upholstery fabrics, clothing, scarves, rugs, pillows, jewelry, and garden ornaments. Butterflies are gracefully ethereal, ladybugs are just plain fun, and bees are welcomed visitors to our gardens, but dragonflies can scare the bejeezus out of many of us. Despite their popularity in the marketplace, most folks know very little about these fascinating insects that often hover disconcertedly at eye level.

I first began observing dragonflies when I moved to the Tidewater. With both a frog pond and fountain in our yard and a mill pond at our backs, dragonflies have been constant summer companions for over two decades and are an endless source of fascination. My herb garden has been the perfect venue, a birdbath and a variety of vegetation providing water, food, and shelter to a half dozen varieties.

If you are lucky enough to have a water feature close by, chances are you’ve already attracted dragonflies. It doesn’t take much; a bubbling fountain, small fish pond, or even a birdbath will do. For insects that spend their lives developing in and living near water, dragonflies are not only attracted to moisture, some of their favorite foods—mosquitoes, midges, and flies—are as well. If you’ve ever been plagued by these annoying pests, welcome a dragonfly or two to your garden.

Dragonflies begin their lives in water. Depending on the species—and there are over 5000—the females deposit their eggs directly onto the water, soft mud, or vegetation at water’s edge. Some species develop soon after they are laid while others hatch weeks later.

The larvae that emerge begin their mobile stage of life as predators, dining on insect larvae, fish spawn, and small tadpoles. Like all arthropods, dragonflies go through a series of molts, the nymphs shedding their exoskeletons repeatedly, some times a dozen times or more, until their growth cycles are complete. You may have seen a dragonfly nymph and didn’t associate it with the familiar aerial denizens of summer.

While browsing in a local garden center one early summer day, I spied a customer approaching the sales counter clutching a plastic bag filled with water in which floated hundreds of pale specks that she waved in front of the garden specialist.

“There are thousands of these little aliens in our swimming pool,” she cried, an edge of hysteria in her voice. “Every time the children enter the pool these things swim toward them and now the kids are afraid to get in the water. I’ve shocked the pool twice and they’re still there!” One glance in the bag and I smiled, nodding, at the nurseryman’s pronouncement: “Dragonflies”. Clearly these creatures were no threat to her children but this pool owner was certainly going to have a bumper crop of dragonflies that year!

When emergence from the larval stage begins, the dragonfly ceases feeding and looks for a spot of relative safety from which to crawl out of the water. Algae mats, reed stalks, aquatic vegetation, and planting beds just above the water will do. Once safely sequestered, its legs stiffen and lock, bodily fluids are strenuously pumped round the body, causing the larva’s casing to split, and an adult dragonfly emerges. As fluid continues to pump, its abdomen and wing veins fill, the wings unfurl and extend. Now full size, the dragonfly rests for several hours, allowing wings and body to dry. Then, ready for flight, it soars like its forebears have done for the past 325 million years.

Odonates, as they are known scientifically, are among the most ancient of living creatures. Dragonfly fossil records predate the dinosaurs by over 100 million years, going back to the Carboniferous age and existing, almost unchanged, since they first emerged.

Often strikingly patterned and colored in shades of green, blue, and red, and with top speeds of nineteen to thirty-eight miles per hour, there are dozens of varieties native to our region. Some are heavy bodied and lack the metallic sheen of their slimmer counterparts who look for all the world like iridescent darning needles. With large, bulbous compound eyes that give them 360° vision, dragonflies and their damselfly cousins eat just about anything they can catch. In addition to mosquitoes and midges, they hunt butterflies, moths, grasshoppers and smaller dragonflies.

Contrary to popular myths, dragonflies do not sting, bite, and are not poisonous. Native American and Asian cultures have venerated dragonflies for centuries, but it was our European forebears who brought dark and fanciful tales of “mosquito hawks”, “snake doctors”, “devil’s needles”, and “devil’s horses” to the New World.
The English name ‘dragonfly’ may have had its origins in a Romanian folktale in which the devil battled St. George and, upon retreating before the saint’s army of angels, entered the body of the saint’s horse, turning it into a winged insect, and flying away. Over the centuries people have become more enlightened about the beneficial qualities of dragonflies, but old myths and fears still persist.

Masters of camouflage, dragonflies lie in wait on surface shapes that often mimic their own; tree branches, fence wires, and plant stalks. For the past few years large twelve spotted skimmers have been partial to the radio antenna of my van parked beside the herb garden.

In their constant quest for food, dragonflies appear extremely curious, often hovering at face level to study each new visitor to their territory. Once satisfied you are not on their menu or a threat, their will quietly settle on the nearest perch to await their next meal. If you are patient and make no quick moves, you can study them in detail.

One of their most striking features is their eyes. Bulbous and compound, they also possess pseudopupils, dark points within the eye that move as the head turns, seemingly following your every move. A number of pseudopupils may be visible simultaneously, giving the dragonfly multiple points of focus, a trait you can appreciate if you’ve ever tried to sneak up on one.

Their wings are wonders of three dimensional aerodynamic design. The characteristic veins serve as spars and stays to support the wings in flight, creating ridges and valleys over the wing surface that change relative to one another as the wings flap, providing lift. Triangles of cells in the wings closest to the body act as dynamic airfoils, folding and changing shape during wing strokes, enabling the dragonfly to bank, climb, swoop, or hover.

Mating is often done in flight, the male capturing and grasping the female, forming a circle known as the wheel position. If mating is successful, depending on the species, the male will either continue to clasp the female while she lays her eggs or will release her but guard against intrusion by other males while she deposits her eggs. Another generation of dragonflies will soon be on its way into the world.

From the laying of eggs through larval development, dragonflies must have a source of fresh water. Some species prefer still ponds while others gravitate to moving bodies of water like rivers and streams. One species even prefers brackish and salt water.

During periods of drought you may see a decline in the number of dragonflies who visit your garden. Weather and climate often determine the movement and population of these long distance aviators. Dragonflies that stray north or south of their range during periods of favorable weather may even lay their eggs in regions far from their normal domain. If favorable conditions persist, shifts in range can and will occur.

After eating voraciously and mating for several weeks, most dragonflies’ lifespans are over. If not picked off by birds, spiders, or other dragonflies, the lucky few die quietly near the waters where they were born. Some species are longer lived and migrate south at summer’s end. None live long enough to complete the cycle and therefore migration takes place in stages involving several generations.

If by now we’ve piqued your interest in these fascinating insects, it’s time to observe them in their natural habitats. There are a number of good field guides available to help identify the various species and all it takes is a little patience, some field glasses, perhaps a camera, and a slather of sunscreen.

James Laswell, director of field research for the Entomology Department of the Texas Agricultural Experiment Station has been fascinated by dragonflies since he was a graduate student at Texas A&M University. He has this to say about his favorite subject:
“Creatures of the sunlight that pirouette on sparkling wings in plain view of all who take the time to look, dragonflies are nonetheless among the most elusive of insects. Few people take the time to get a close look at these ever-vigilant aerial predators, and fewer still know what they are seeing. Interaction with dragonflies can be entertaining and rewarding. It can also be used to catch the interest of children and increase their appreciation for these delightful insects.”

So next time you spot a dragonfly, pause awhile and admire one of nature’s most beneficial handiworks. They don’t mind being stared at if you don’t mind being stared back in return.