Those colorful winged creatures of the air, the dragonflies, are seen from spring well into the fall, but it’s now that their numbers peak. To get into the hobby of “dragonflying” it helps to have binoculars that focus under 10 feet, plus a good field guidebook such as “Dragonflies of the North Woods” by Kurt Mead.
We look for dragonflies near lakes, ponds, streams and wetlands, but they are strong fliers, and their many-veined transparent wings can take them miles from water, where they spent one to three years in the nymphal stage. Researchers have marked individual dragonflies and found that many live six to eight weeks as fully formed adults, with territories no larger than an Olympic swimming pool.
Dragonflies, also known as darning needles or stingers, are reported to be dangerous, and they are, but only to smaller insects such as gnats and flies, which they catch on the wing. Sometimes a dragonfly catches so many mosquitoes that there will be a hundred or more in its mouth at one time. Thus, another name for the dragonfly is the mosquito hawk.
While working with my summer field biology students, years ago on a wetland trail, half a dozen dragonflies joined us and gobbled up mosquitoes that came close. We had biological control happening right in front of our eyes. We observed that, like hummingbirds, dragonflies can hover in the air or suddenly dart upward, downward or to one side. Their glistening wings carry them at speeds of 30 miles per hour or more; each pair of wings strokes alternately, the front pair going up while the hind pair goes down, the motor muscles moving them at a rate of 30 or 40 strokes per second.
Jim Gilbert’s Nature Notes are heard on WCCO Radio every Sunday at 7:15 a.m. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.