Common Green Darner (Anax junius)

Zipping through the air in pursuit of mosquitoes, moths, and other prey on the wing, the common green darner dragonfly is a familiar aerial sight throughout Minnesota on sunny summer days.

Life Cycle. A green darner begins as an egg deposited in an aquatic plant stem at the edge of a pond or lake. After a week or so, a tube-shaped immature form, known as a nymph, emerges. Gobbling up underwater insects, tadpoles, and sometimes fish, the nymph grows, splits out of its skin, and grows more. After going through perhaps a dozen such stages, it emerges as a winged adult, ready to chase, capture, and consume insects in the air rather than the water.

Appearance. Adult green darners are about 3 inches long, with a tube-shaped body and four transparent wings that operate independently, allowing it to move rapidly, hover, and fly both forward and backward. The thorax—the body midsection where the wings and legs get their power—is mainly green. The abdomen (the needle part) tends to be blue in males and rusty gray in females. However, coloration can vary from one insect to another and includes shades of pink, brown, yellow, and more. A black spot on the top of its head can help you tell the common green darner from other dragonflies.

Range and Habitat. Green darners live throughout Minnesota, including in urban areas, typically in or near ponds, lakeshores, and slow-moving streams. Like other dragonflies, green darners can rapidly vibrate their wings to generate heat under cold conditions.

What They Eat. Green darners and other dragonflies are carnivores, voraciously consuming other insects. Nymphs occasionally nosh on tadpoles, small fish, and each other.

What Eats Them. Green darners provide food for birds, spiders, and even other green darners. American kestrels find them to be valuable sustenance during fall migration.

Surviving Winter. Green darners survive Minnesota winters in one of two ways. Many migrate to the Gulf Coast, flying up to 90 miles a day, from July to October. There they go through at least two generations, with new adults making the trek north in spring. Other green darners remain in Minnesota, wintering as nymphs beneath pond ice.

About Those Eyes. Green darners have remarkably well-developed vision. Each eye is composed of more than 28,000 light-sensing elements, far more than most other insects. Their eyes allow the dragonfly to see in back as well as in front of itself so it can detect prey—and predators—in all directions. Researchers suspect green darners can detect polarized light to find their way during migration.