By Susan Benson,
CNHM Director of Education
This past week I was bitten by a dragonfly. It was April 27, to be exact. I hope no one gets too alarmed by this statement. Dragonflies are not exactly one of the animal world in which we fear. This event, however, goes down in my phenology journal. I have always had a close relationship with insects, as I have been an avid fan since I was in second grade. I could share the most inane details about certain insects that would bore people in minutes. Dragonflies land on me, or near me, regularly when I am near water. I have always thought we were big buddies. As my fiancé and I were walking down to the Namekagon river, he asked me if dragonflies bit, and I promptly answered, “they could, but they never would.” I was in the midst of rescuing a damaged, but beautiful specimen. Just as I was ready to put it down, it bit me, again and again! For a moment, I felt great sympathy for mosquitoes.
This dragonfly was a green darner, easily identified by their green thorax and bright blue abdomen. They also have an obvious bull’s eye pattern on top of their face. Green darners are the first dragonfly to be seen in early spring, and their second “flight” begins in early August through October. In the fall, northern juveniles migrate south, flocking together in the thousands. They fly south to the southern states, and their offspring fly north in the spring. They arrive in our region, lay eggs, and those eggs become the juveniles that leave us this fall. Local birders believe that the green darner migration occurs at the same time the American kestrel migration happens down the North Shore, and it is believed that the kestrels feed on the green darners as a migratory fuel source. It is possible that we have a non-migratory population as well. These residents overwinter as nymphs and hatch in the spring.
Green darner eggs are laid inside stems of aquatic plants. The female uses her sharp, egg-laying ovipositor to pierce the plants. It is during this egg-laying time that females must beware or they may become dinner to a fish. The hatching darner nymphs, which to me look almost “alien,” live in the water and feed primarily on fish eggs, tadpoles and aquatic insects. Adults eat fly midges, mosquitoes, caddisflies, butterflies and moths, and other flying insects. In general, this species prefers fishless habitats that have still waters such as permanent or temporary ponds, marshes, or slow streams with emergent vegetation.
Green darners are nicknamed because their abdomen looks like a darning needle. They are also called mosquito hawks. With their outstanding flight abilities and almost 360-degree sight, they can fly fifty miles per hour and kill prey larger than themselves. They can also reach altitudes of nearly 18,000 feet. Scientists track their movements through tiny locating beacons which allow us to know so much about these species.
I could impress everyone with my knowledge that dragonflies belong to the order Odonata. A translation of this word is “toothed ones,” due to the awesome lower lip, which used to capture and hold their prey while their mandibles do the eating. Indeed, I now know all about their mouth parts, and have the two millimeter “owie” to prove it, along with a whole new dose of respect and admiration for these insects.
For over 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.