Dazzling Dragonflies

Enlarge Image Image Gallery For more than 300 million years, the whirring wings of dragonflies have shimmered in the light of our planet’s sustaining star. BILL BEATTY

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The next time you spy a dragonfly skimming over a pond or darting and diving among streamside reeds, consider this: For more than 300 million years, the whirring wings of dragonflies have shimmered in the light of our planet’s sustaining star. Long before the first two-legged mammals stumbled onto the scene, before the first birds, before the first dinosaurs, dragonflies thrived in the moist jungles that once covered much of Earth. And some of them were huge: Etched in the fossil record are the veined wings of dragonflies with wingspans of nearly 2½ feet.

That the dragonfly has survived so long while other creatures have come and gone is no mere accident. Few organisms — past or present — can claim a more perfect design for perpetuation. Although human eyes are easily beguiled by their sparkling flight on gossamer wings, these insects are hardly mere “flying flowers.” Dragonflies are tough, deadly predators and determined progenitors — both beauty and beast, driven on a reproductive path that stretches from prehistory to time’s horizon.

Amazing Diversity

Scientists place dragonflies in an insect order all their own, Odonata. They further divide that group — more than 5,500 species worldwide — into two suborders: the “true” dragonflies (Anisoptera), and damselflies (Zygoptera).

It’s easy to distinguish between a dragonfly and a damselfly. A resting dragon holds its four wings out flat, to its sides, and the hind pair is larger than the front. A damselfly at rest folds together all four of its wings, which are essentially the same size, vertically over its body. And while damsels’ eyes are on opposite sides of their heads, dragonfly eyes are close together. Despite these distinctions, most scientists take the practical route and use the word “dragonfly” when referring to both the dragonfly and the damselfly.

In the United States, there are about 450 species of dragons and damsels. In size, they range from the elfin skimmer, which measures just over three-fourths of an inch long — about the diameter of a nickel — to the giant darner, which stretches 4¼ inches.

Size, however, is the least of the physical features that define dragonfly diversity. A dragonfly’s eyes, for instance, may be green, black, copper, red, blue or some combination thereof. And when it comes to body shape, dragonflies are every bit as diverse as humans. Some are thick at the thorax, where the wings and legs attach; some have thin, needlelike abdomens; others have abdomens that taper from wide in front to narrow at the tip, or jut slightly in and out along the entire length, like miniature stalks of bamboo.

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