Damselflies: Live Fast and Die Young

Northern bluet

This bright and handsome damselfly, pausing on a step stone in my garden, is a male Northern bluet (Enallagma annexum), one of 462 species of damselflies and dragonflies found in North America. They make up the two main subdivisions of a very distinctive group of insects known as Odonata (Greek for tooth), which refers to their powerful and sharply toothed jaws, adapted for biting and chewing their prey.

Damselflies can be distinguished from dragonflies by their smaller size and their position when at rest: Damselflies typically hold their bodies horizontally, with their tear drop-shaped wings neatly and elegantly folded together over their abdomen, while dragonflies generally hold their wings flatly, outstretched and perpendicular to their body.

I’ve wondered about the common names. Since “damsel” conjures up an image of a fair maiden—most likely in distress—I imagine that the damselfly was so named because it is more delicate looking than a dragonfly and isn’t as tough and strong a flyer. Plus, proverbial dragons kept damsels in their caves, didn’t they? But now we need to ask, why are dragonflies called what they are? According to a 1958 book by Eden Emanuel entitled Folklore of the Dragonfly, it’s theorized that the common name emerged due to an ancient Romanian folktale, in which the devil turned a beautiful horse ridden by a saint into a giant flying insect. The Romanians supposedly called this giant insect (when translated into English) “St. George’s Horse” or “Devil’s Horse.” Peasants probably considered the Devil’s Horse a giant fly, and it’s surmised that they started referring to it as “Devil’s Fly.” Emanuel concluded that the Romanian name for Devil’s Fly was erroneously translated into English as Dragon Fly and this then evolved into the present-day “dragonfly.”

Gradual Metamorphosis

The female Northern bluet is generally greenish-yellow or tan, with a black abdomen. She lays her eggs in submerged vegetation; upon hatching—typically late spring to early fall—the young nymphs (or naiads) are small and wingless, but fully functional, so they don’t go through larval or pupal stages like most other insects do. Nymphs spend their time (often years) underwater in bogs, lakes, ponds, or rivers, where they molt (shed their skin) about a dozen times while growing. Fierce predators of aquatic organisms, they hide in submerged vegetation and attack the larvae of smaller insects such as mosquitoes and mayflies. When they are about an inch long, they crawl out of the water onto rocks or grasses and such. After a brief sunbath, their skin splits down the back and they struggle to pull themselves out of their shabby old skin one last time. Voila! Metamorphosis complete, they are now all grown up and it’s time to inflate their new wings and abdomen and harden fresh legs, all of which likely takes a lot of energy. Adults generally live less than two weeks, breeding and feeding—just enough time to live fast and die young.

Like dragonflies, damselflies’ large, bulging eyes have thousands of honeycomb-shaped lenses that give them an ability to see in all directions and make them formidable predators of other insects. Adults are swift aerial hunters, typically preying on mosquitoes, small moths, and various flies. Fascinating research shows that Odonata don’t dive and turn in reaction to their prey’s movements—instead, they are able to predict those movements before they happen. But what goes around comes around: Both damselfly nymphs and adults are consumed by birds, frogs, fish, and, yes, dragonflies.

Conservation

Dragonflies and damselflies go way back, predating dinosaurs by at least 75 million years. Fossils of ancient ancestors dating roughly 300 million years ago were gigantic—the largest insects ever to live—with wingspans of about 30 inches! Northern bluets are somewhat common damselflies, often found near freshwater—streams, rivers, and other watery places (even human-made ponds)—but their dependence on it makes them very vulnerable.

All damselflies and dragonflies are good indicators of the diversity and health of aquatic ecosystems, their presence suggesting that a body of water is fairly unpolluted. Destruction or alteration of wetland habitats, pollution, and pesticides are the greatest threats to Odonata species worldwide. Without clean water they cannot breed, and without insect life they cannot eat. Needless to say, alteration of their habitat through climate change will likely pose a severe threat to future populations.

On pleasant, sunny days I often notice dragonflies and damselflies patrolling my organic, “real” garden. Should these brainy little hunters find their way into yours, consider yourself very fortunate!

 

© 2015 Eileen M. Stark

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