JULY
1988

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

7-28-88

INSECT DRAGONS

Skimmers, Biddies, and Darners.  No, these aren't the latest rock bands.  They are dragonflies.

Dragonflies are among the oldest insects.  Some call them living fossils.  Today's dragonflies look about like their ancestors that lived nearly 300 million years ago.  Dragonflies roamed the skies during the 100-million-year reign of the dinosaurs.  One such ancient dragonfly was itself dinosaur-sized.  This insect had a wing span of nearly 27 inches.

Immature dragonflies, called nymphs, live in the water.  Adults do fly far from water on their aerial forays, but they are most commonly found near water habitats.

Both adults and nymphs are predators.  They feed primarily on other insects, although large dragonfly nymphs have been known to capture and devour small fish. 

Adult dragonflies capture prey while on the wing.  Although the dragonfly has a fearsome-looking set of jaws, it procures its meals by an unusual method.  The dragonfly shapes its six legs into a basket.  Then, in an insect version of an aerial dogfight, overtakes prey from behind, snaring the potential meal in its legs.

The dragonfly sometimes eats on the wing – sort of a “meal to go” in the insect world.  For a more leisurely dining experience, the dragonfly will perch on vegetation before devouring the hapless victim.

Because dragonflies destroy a number of insects, including mosquitoes, gnats and flies, they are beneficial.  Even though dragonflies are predators, they are harmless to people.  These insects neither sting nor bite.  However, dragonflies have not always been considered harmless.

There are a number of superstitions associated with the dragonflies.  For instance, in some rural areas of the United States, the common name “snake doctor” was acquired because people assumed that the dragonfly acted as a guard to snakes.  This may have originated because both snakes and dragonflies share marshy habitats.

Another superstition held that dragonflies could sew together various parts of the human body, including lips, nostrils, eyelids and ears.  This belief gave rise to the common name darning needle or devil's darning needle.

Some of the fear of dragonflies, and some of the superstitions, are probably based on the fearsome look of the insect.  However, part of the mystique of the dragonfly is due to its territorial nature.  Male dragonflies set up territories just as do certain birds and mammals.  The dragonfly then defends its territory against other dragonflies.  Such territorial defense leads to spectacular battles among these master aerialists.  The dragonflies also check out other intruders in their territory – a surveillance activity that some folks might interpret as hostile behavior.

The next time you spy a beautiful, brightly colored dragonfly doing aerial maneuvers, pause for a moment and watch closely.  You are watching an animal that has been flying for 300 million years.  With all of that practice it's no wonder dragonflies are good at flying!

 

Writer: Tom Turpin
Editor: Olivia Maddox