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Last updated on April 20, 2014 at 17:20 EDT

Dragonfly

The Dragonfly is an insect belonging to the Order Odonata and suborder Anisoptera. It is characterized by large multi-faceted eyes, two pairs of strong transparent wings, and an elongated body.

The dragonfly’s diet consists typically of mosquitoes, midges and other small insects like flies, bees, and butterflies. They can be found around lakes, ponds, streams, and wetlands because their larvae (known as nymphs) are aquatic. Dragonflies do not bite or sting humans. Instead they are valued as a predator that helps control the populations of insects that do, such as mosquitoes.

General facts

The life cycle of the dragonfly varies from six months to as much as six or seven years. Female dragonflies lay eggs in or near water, often in or on floating or emergent plants. Most of their life cycle is spent in the larval (nymph) form, beneath the water surface, using internal gills to breathe, catching other invertebrates or even vertebrates such as tadpoles and fish. In the adult stage, larger species of the dragonfly can live as long as four months. Dragonflies have very good eyesight due to their unique eye structure which can have up to 30,000 eye facets. Each facet is a separate light-sensing organ, or ommatidia. These facets are arranged to give the dragonfly a nearly 360° field of vision.

Much larger dragonfly species existed in the past – the largest, found as a fossil, is an extinct Protodonata named Meganeura monyi from the Permian period with a wingspan of 27.5″“29.5 in (70″“75 cm). This compares to 7.5 in (19 cm) for the largest modern species of odonates, the Hawaiian endemic dragonfly, Anax strenuus. The smallest modern species recorded is the libellulid dragonfly, Nannophya pygmaea from East Asia with a wing span of only 20 mm, or about 3/4 of an inch.

The Common Green Darner dragonfly (Anax junius) is nicknamed “Darning Needle” because of its body shape. It is one of the biggest and fastest-flying dragonflies, able to reach speeds of 53 mph (85 km/h).

Damselflies (Suborder Zygoptera) are often confused with dragonflies, but the two insects are distinct: damselflies at rest hold their wings together above the body, whereas dragonflies at rest hold them out, either horizontally or slightly down and forward. Also, the eyes on a damselfly are separated, while those of the dragonfly are nearly touching. Both are members of Odonata, and their life cycles are similar.

It was recently discovered that dragonflies employ an optical illusion to stalk other insects who invade their territory. New research suggests that a dragonfly can move in such a way as to project itself as a stationary object while speedily attacking its victims. These findings illustrate for the first time how dragonflies use complex camouflaging techniques during aerial combat.

Some common species

  • Emperor, Anax imperator
  • Black-tailed Skimmer, Orthetrum cancellatum
  • Common Whitetail, Libellula lydia
  • Migrant Hawker, Aeshna mixta
Dragonfly