by Janice Welsh
Dragonflies and damselflies are the helicopters of the insect world. With their bulging eyes, long tails, and tapered wings, they look like helicopters. In fact, they maneuver like helicopters too. They can fly backwards and change direction in just one body length of air space. They can glide, hover in midair, and make sharp turns. Some can fly up to 35 miles per hour.
Like all insects, damselflies and dragonflies have six legs, two pairs of wings, two antennae, and three body parts - head, thorax, and abdomen. They wear their skeletons on the outside of their bodies. This tough outer covering is called an exoskeleton.
Dragonflies and damselflies live in and near ponds, streams, and lakes. Of 5,500 species of dragonflies worldwide, 86 are known to live in Minnesota. Minnesota counties with the most known species of dragonflies are Anoka, Washington, Pine, Lake Clearwater, and Cook.
A dragonfly's life begins as an egg laid underwater.The egg hatches into a nymph. The nymph eats tadpoles and minnows. The growing nymph molts its exoskeleton, just as a snake sheds its skin. The nymph crawls out of the water onto a plant, rock, or log and molts one last time. Its abdomen inflates and blood flows into its wings, which slowly unfold, dry, and stiffen. This transformation from egg to adult is called metamorphosis. These creatures may live as nymphs for two years. While flying, the male fertilizes the eggs of the female. The male holds onto the female as she deposits her eggs in the water.
The University of Minnesota Insect Collection has about 2,865,000 insect specimens, representing 43,000 species found in the United States and many other parts of the world.
The collection started in 1897 with insects and spiders from the North Shore of Lake Superior. Current staff members have made expeditions to collect insects in Costa Rica, Ecuador, Peru, French Guiana, and Trinidad, making this one of North America's major collections.
University research and teaching programs use the collection.
People who study insects are called entomologists. The Young Entomologists' Society is a non-profit group that helps young people study insects. For membership information, contact Y.E.S. Inc. at YESbugs@aol.com.
Also available from YES is Creepy Crawlies and the Scientific Method by Sally Stenhouse Kneidel. This book for teachers tells how to study pond ecology in the classroom. The book describes more than 100 hands-on experiments for children.
A Naturalist's Eye for Dragons
State park naturalist Mark Carroll has been interested in dragonflies and other insects since he was a kid. In the clover fields near his house, Mark and his friends had contests to see who could get the most bumblebees into a jar. Mark's mother made him a butterfly net and turned old shoe boxes into storage containers for his collections. On the kitchen table, he raised monarch butterflies.
As a student at St. Cloud State University, Mark studied all kinds of wildlife. He worked on a study of restored wetlands - ones that people drained of water and later fixed to hold water again. He wanted to see how quickly aquatic insects came to live in the restored wetlands. Mark made maps to show other researchers where different dragonfly species live in Minnesota.
Mark earned a bachelor's degree in earth sciences and a master's in biology, then joined the Department of Natural Resources as a naturalist.
At Sibley State Park in west-central Minnesota where he works, Mark has counted more than a dozen species of dragonflies. He shows dragonfly slides and takes park visitors on hikes to see what he calls "dragons in the air." To find out more, call the DNR Information Center at 651-296-6157 or 1-888-646-6367.
Janice Welsh, author of this article, runs Project WILD, a DNR program for schools.
A complete copy of the article can be found in the July-August 1996 issue of Minnesota Conservation Volunteer, available at Minnesota public libraries.