Feature Article - for release the week of August 20, 2006

Dan Culbert - Extension Horticulture Agent

DAMSELS AND DRAGONS

Notice some flying dragons recently?  When summer rains begin, mosquito populations increase, and soon afterwards our Florida Yards host hoards of dragonflies that seek a welcome meal.  Today’s column highlights some habits of these interesting beneficial insects.  Information for this column comes from the late Ohio State University Entomologist Dr. Donald J. Borror and UF Extension Entomologists.

DIVERSITY

UF student Cat Smith, 21, watches a dragonfly devour a skipper butterfly in the Natural Area Teaching Laboratory at the southwest corner of UF’s main campus in Gainesville – . Smith was participating in the Perspectives in Wildlife Ecology and Conservation class. Photo:  UF/IFAS Josh Wickham

Dragonflies and Damselflies are among the most attractive of the insects.  They have been preserved in fossils that are 250 million years old – from the dawn of the dinosaur era. Their glittering colors and beneficial habits have encouraged many amateur bug watchers to become professional entomologists.

Dragonflies are lumped together with the damselflies into a group of insects known as the Odonata.  They have some unusual features:

·        The head is covered with large prominent eyes that are often strikingly colored.

·        Short bristle-like antennae and chewing mouthparts are also noticeable.

·        Front and rear wings are not linked together, but move independently. 

·        A long thin abdomen serves as the insect’s lung and holds the reproductive organs.

The dragonfly is a master of the air, daring it to hover within an arm's reach. At rest, its wings lie flat, at right angles to the body.  Dragonflies can be several inches long - but a fossil is known with a 28 inches wingspan!

Damselflies are not as showy or noticeable. They are smaller, thinner and show less aerial acrobatics than the dragonflies.  At rest, damselflies hold their wings over their backs, either together or spread out in a V-shape.  This feature of how the resting wings are held is the best way to tell the “dragons” from the “damsels”.  Damselflies usually stay close to a pond’s surface, while dragonflies can zoom up into the air and out of sight.

Adults consume many mosquitos, midges and other small insects, and help keep these insects under control.  Their prey is usually moving and often caught in flight.   If you see swarms of these “mosquito hawks” know that many small pests are also being consumed.

Adult dragonflies will join in the air, making a formation that is called a wheel.  Some males are “jealous” and may chase off other potential mates.  Females lay single eggs into some suitable vegetation such as dead wood or reeds near the edge of ponds or canals.  

The eggs will drop into the water and hatch into naiads.  These are free living, aquatic predators that feed on other aquatic insects, including their own brothers and sisters.  Larger naiads can eat fish fry, or may in turn become food for other fish or frogs.  

The lower lip of the naiad can be extended like an underwater harpoon.  They move rapidly by sucking water into their abdomen and then spitting it out like a jet engine.  Damselfly naiads have three feather-like appendages at the end of its abdomen; these are used like gills for breathing and are whipped back and forth for movement.

Naiads molt as they grow and develop for several months; while some species can take 5 years to mature.  When fully grown, they crawl out of the water onto a stick or stone and molt into the winged adult.  The newly emerged insects are soft-bodied and may not develop full coloration and flight capabilities for several days. 

Names for these insects are based on their wing characteristics, flight patterns and reproductive habits.  Common dragonflies include the Clubtails, Darners, Skimmers and Biddies.  Damsel flies include broad-winged, narrow-winged, spread-winged, bluets and forktails.  The hoards of local dragonflies that have spots on their wings are named the ten-spot skimmer; those with yellowed wings are the amberwings.

TAMING THE DRAGONFLY

Because they are beneficial, no “pest management” recommendations exist for dragonflies.  Stories about dragonflies stinging, biting or entangling themselves in hair are just folklore – and the darners do not sew up the lips of bad boys.  Because of their appetite for mosquitos, they should be encouraged and celebrated in Florida Yards.  The most damage they can cause is to clog up a car’s radiator if driving into mosquito clouds.

Unlike butterflies and beetles, dragonfly colors rarely preserve well in collections.  Entomologists have learned that their capture is often difficult, and prompt mounting and preservation techniques must be used to preserve their brilliant colors.  Some excellent references are available to help dragonfly collectors - call or email if you would like some of these sources.

For the rest of us, we can appreciate the dragons and damsels of summer best in their natural, living state.  While there are many suggestions for butterfly gardening, there are few for encouraging dragonflies. Properties with water gardens, ponds and fresh water can provide help to the damsels and dragons by:

• •                     Reducing pesticides and fertilizers that enter these bodies of water and can kill the naiads and eliminate their food sources.

• •                     Provide aeration in ponds to increase oxygen for the larval naiads - some survive only if the water is bubbling like in brooks and streams.

• •                    Resist the temptation to remove sediments from pond bottoms, as it provides habitat for both predators and prey.

• •                     Allow these creatures some space in your pond, watch for egg laying and adjust pond maintenance tasks during this time.

• •                     Include aquatic plants and retain sticks and rocks on the water’s edge for naiads to emerge from the water.

I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on dragonflies, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 3 PM on Tuesday afternoons.