On walks in the Campus Natural Areas, most of us have probably noticed long slender and colorful bugs, like winged darning needles, hovering in the air, often over the water. We recognized them as dragonflies and walked on. Now perhaps it's time to take a closer look at this marvelous creature.
Meet the Insect
Of the order Odonata, dragonflies have three body parts: head, thorax, and abdomen. Their six legs and four wings also characterize them. They pass through several stages before they appear as the winged creatures that we see about rivers and ponds. Eggs, laid in or near water, hatch into larvae. “Odonata” means “toothed jaws.” These small insects are tough predators. In fact, in the larval state, they are the top of the food chain in ponds and streams, after the fish.
At the appropriate time, the larvae undergo a metamorphosis and become the familiar dragonfly that we notice. The newly hatched dragonfly, known as a teneral dragonfly, moves away from the water to mature. At this stage in life, it is very susceptible to predation from creatures, such as birds. When mature, the dragonflies return to the water to mate and the cycle begins again.
Where are they now?
Certainly if you walk the Campus Natural Areas now, you will not see any dragonflies. So just where are they? Most are overwintering in the larval state, but one common Wisconsin species, the Common Green Darner, has migrated south for the winter. Dragonflies can begin to appear as early as April, but the best time to see dragonflies in the CNA is from June through September.
Dragonfly Watching
Your search for dragonflies will be greatly enhanced by a pair of close-focusing binoculars. Ideally the binoculars should be able to focus at a distance of 8 feet, and 4 feet is even better. Once you have spotted a dragonfly, to know what species it is, consult a guidebook, such as Common Dragonflies of Wisconsin by Legler and Westover (available from the author) or Dragonflies through Binoculars by Dunkle .
Within the CNA, recommended places to check for dragonflies include the 1918 Marsh and the Biocore Prairie. If you want to see dragonflies in the CNA, it is best to look on a sunny day.
Expected Dragonflies in the CNA
In Wisconsin, 110 species of dragonflies have been recorded. Some common local species to expect to see in the CNA include Common Green Darner, Black Saddlebags, and Twelve-spotted Skimmer. Common Green Darners fly constantly, but their green thorax and bright blue abdomen are easily recognized. The dark wing spots near its body make the Black Saddlebags appear to carry saddlebags, hence its name. This tiny insect can fly at 17 miles per hour. The Twelve-spotted skimmer gets its name from the three dark spots found on each of its four wings. Three other common dragonflies are Common Whitetail, White-faced Meadowhawk, and Widow Skimmer.
Dragonflies can indicate the health of a body of water. They are adversely affected by pollution and pesticide run-off. Since they eat lots of insect pests, like mosquitoes, we ought to keep the habitat healthy for dragonflies.
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