How to Identify the Common Green Darner Dragonfly

Habits and Traits of the Common Green Darner

Look for a bulls-eye marking on the head of common green darners. Males have blue abdomens.
Look for a bulls-eye marking on the head of common green darners. Males have blue abdomens and a green thorax. Flickr user Benimoto ( CC license)

The common green darner, Anax junius, is one of the best-known North American dragonfly species. The green darner is easy to spot, thanks to its large size and bright green thorax, and can be found almost anywhere in North America.

Identifying the Green Darner Dragonfly

Green darners are strong fliers and rarely perch. Look for adults flying low over ponds or bogs during the breeding season. This species migrates seasonally, often forming large swarms when heading south in the fall.

Green darners are one of the earliest species to appear in northern habitats in the spring.

Both male and female green darners have an unusual blue and black "bulls-eye" marking on the frons (or forehead, in laymen's terms), just in front of their large, compound eyes. The thorax is green in both sexes. The long abdomen is marked by a dark line, which runs down the center of the dorsal surface.

In immature common green darners of either sex, the abdomen appears red or purple. Mature males bear a bright blue abdomen, but in the early morning or when temperatures are cool, it may turn purple. In reproductive females, the abdomen is green, matching the thorax. Older individuals may have an amber tint to their wings.

Classification

  • Kingdom - Animalia
  • Phylum - Arthropoda
  • Class - Insecta
  • Order - Odonata
  • Family - Aeshnidae
  • Genus - Anax
  • Species - junius

What do Green Darners Eat?

Green darners are predaceous throughout their lives.

The large, aquatic nymphs prey on other aquatic insects, tadpoles, and even small fish. Adult green darners catch other flying insects, including butterflies, bees, flies, and even other, smaller dragonflies.

Their Life Cycle Follows All Dragonflies

Like all dragonflies, the common green darner undergoes simple or incomplete metamorphosis with three stages: egg, nymph (sometimes called larva), and adult.

The female green darner oviposits her eggs while in tandem with her mate, and is the only darner in North America to do so.

Common green darners oviposit their eggs in aquatic vegetation by carefully cutting a slit in a stem or leaf, and placing the egg inside it. This probably provides her offspring with some protection until it hatches.

The aquatic nymph matures over time in the water, molting repeatedly. It then climbs up the vegetation until it's above the water's surface, and molts one last time to emerge as an adult.

Habitat and Range

Green darners live near freshwater habitats, including ponds, lakes, slow-moving streams, and vernal pools.

The green darner has an extensive range in North America, from Alaska and southern Canada all the way south to Central America. Anax junius is also found on islands within this geographic range, including Bermuda, the Bahamas, and the West Indies.

Sources

Field Guide to Dragonflies and Damselflies of New Jersey: Allen E. Barlow, David M. Golden, and Jim Bangma: New Jersey Department of Environmental Protection; 2009.

Dragonflies and Damselflies of the West; Dennis Paulson; Princeton University Press; 2009.