<< Back 8/7/02 The Naturalist's Corner By Don Hendershot Dragonflies and damselflies are in the order Odonata, from the Greek, odon-o which means tooth. They are named for the strong teeth found on the mandibles of most adults. Adult dragonflies are robust, strong flying insects. North American species range from about one to four inches in total length with a wingspan of five to six inches. The wingspan of some tropical species might reach eight inches. But even that pales to the dragonfly’s prehistoric ancestors. Fossil records from the Carboniferous Period reveal specimen with wingspans of over 25 inches. Damselflies are smaller, more fragile looking insects and weaker flyers, often moving from plant to plant in search of food. At rest, dragonflies keep their wings flat, perpendicular to their body. Damselflies fold their wings above their backs. Dragonflies and damselflies are voracious predators as larvae and adults. Adult dragonflies feed on any number of small flying insects such as gnats, mosquitoes, black flies, horse flies and deer flies. Damselflies stick to the small end of the spectrum. Larger dragonflies will feed on other dragonflies and damselflies. As aquatic larvae (naiads) Odonates feed on a variety of aquatic life including small mollusks, crustaceans, mayfly naiads and other creatures. The naiads of larger dragonflies will even go after small fish and tadpoles. Naiads have a specialized lower lip or labium used for capturing prey. The labium folds under the head and thorax but can be “shot out” to catch prey in an astounding 25 milliseconds. Damselfly naiads breathe through appendages at the posterior end of the abdomen known as lamellae. The gills of dragonfly larvae are located internally within the rectum where contraction of the rectal muscles circulates oxygenated water. There are about 11 families of Odonata in North America composed of over 400 species. There are more than 5,000 species worldwide representing 29 families. Dragonflies generally mate in midair while damselflies more often come together on vegetation. Male Odonates have appendages at the end of their abdomen which lock into grooves on the female’s head and/or thorax. During breeding season, pairs are often seen flying, locked together, looking for a suitable place to lay eggs. Some species simply scatter their eggs over water from the air. Others deposit individual eggs into vegetation above and below the water’s surface. In many species the male will guard the female and/or the eggs during egg laying. Most Odonates spend about one year as naiads. Some spend only a couple of months and others may remain in the larval stage for up to five years. Dragonflies and damselflies undergo numerous molts as naiads. For its last molt, the transition into adult insect, the nymph climbs out of the water and attaches itself to some object such as a plant stem or rock. The skin opens along the thorax and the adult emerges. There is no pupal stage with Odonates as in butterflies and moths. It generally takes a couple of hours after the adult emerges for the body and wings to “cure” or harden enough to withstand flight. Once the insects have mastered flight they leave the water for a short period while they sexually mature. This is usually a couple of weeks but may be longer in species that migrate. The life span of adult Odonates is from two weeks to about three or four months. As mentioned earlier, dragonflies are strong flyers and some migrate great distances. There are records of dragonflies discovered hundreds of miles off the coast of Australia. Some dragonflies are quite territorial and may be seen zooming back and forth along the stream or pond bank, chasing intruders. All Odonates require water for the larval stage but some adults, especially the meadowhawks may be found foraging quite a distance from any water. And almost any water will do, from vernal pools to streams, to rivers and lakes. Dragonflies come in a kaleidoscope of colors and patterns from stark white to iridescent blue, green and/or yellow to velvety red and almost any tint or combination in-between. Wings may be clear or spotted or amber tinged. The large, round compound eyes of dragonflies may have as many as 28,000 individual facets allowing the hunter to spot insects in almost any direction even while flying at great speeds. Some dragonflies can attain speeds of more than 30 m.p.h. I remember, as a kid, sitting in a john boat on Horse Shoe Lake watching mosquito hawks zoom past to stop occasionally and rest at the tip of my cane pole or even on the monafilament hanging over the water. I was amazed then. I am amazed now. (Don Hendershot can be reached at don@smokymountainnews.com)