Dragonflies are insects that have large multifaceted eyes, two pairs of strong transparent wings, sometimes with colored patches and an elongated body.
There are more than 5,000 different species of dragonflies.
Dragonflies are found on every continent except Antarctica, they live in temperate, tropical and terrestrial locations.
Dragonflies start their life in water, therefore they are often found near water: ponds, lakes, canals, streams, rivers and swamps. Since dragonflies are very good flyers they can sometimes be found a very long way from water.
Dragonflies come in many sizes. The average size of a dragonfly is from 2.5 to 10 centimeters (1 to 4 inches) in length.
Many adult dragonflies have brilliant iridescent or metallic colors produced by structural coloration, making them conspicuous in flight. Their overall coloration is often a combination of yellow, red, brown, and black pigments, with structural colors.
Dragonflies are powerful and agile fliers, moving in any direction, and changing direction suddenly. In flight, the adult dragonfly can propel itself in six directions: upward, downward, forward, back, to left and to right.
They are some of the fastest flying insects in the world reaching speeds of over 48 kilometers (30 miles) per hour.
Their fast flying speeds make dragonfly wing beats so fast you can barely see the movement. Up to 30 flaps per second help the insects hover as well. At such speeds, a dragonfly can beat her wings up to 1,800 times per minute.
Relative to other insects, dragonfly vision is extraordinarily good. The head consists almost entirely of two huge compound eyes, which gives the dragonfly nearly 360° vision. Each compound eye contains as many as 30,000 lenses, or ommatidia. A dragonfly uses about 80% of its brain to process all this visual information. They can see a wider spectrum of colors than humans. This remarkable vision helps them detect the movement of other insects and avoid collisions in flight.
Adult dragonflies hunt on the wing using their exceptionally acute eyesight and strong, agile flight.
Adult dragonflies mostly eat other flying insects, particularly midges and mosquitoes. They also will take butterflies, moths and smaller dragonflies. The larvae, which live in water, eat almost any living thing smaller than themselves. Larger dragonfly larvae sometimes eat small fish or fry.
The lifespan of a dragonfly is found to consist of two-stages. After breeding the female dragonfly will lay her eggs on or near water or in a place that will fill with water. Once the eggs have hatched the first stage in their lifestyle can begin. At this stage, it is an aquatic larvae, also called ‘nymph‘. This stage will generally last between one and three years.
Once the nymph is fully grown, and the weather is right, it will complete the metamorphosis into a dragonfly by crawling out of the water up the stem of a plant. The nymph will shed its skin onto the stem of the plant and will then be a young dragonfly.
At the shortest the life cycle of a dragonfly from egg to the death of the adult is about six months. There are even dragonflies that live for several years as aquatic larvae before they emerge and live for a few months as adults.
Several species of dragonfly are known to collect in large swarms. In most cases this happens because there is a lot of food in the area. It may also be a “courting” group with males actively searching for females. Some dragonflies gather in swarms before migration.
Some species of dragonfly migrate.
A dragonfly called the globe skimmers (Pantala flavescens) has the longest migration of any insect — millions of dragonflies are flying 11,000 miles across the Indian Ocean from India to Africa.
Dragonflies are primarily eaten by insect-eating birds, frogs, big spiders and fish. To avoid being eaten, adult dragonflies will use their quickness and agility to out fly predators who are pursuing them and will also hide in vegetation if it is too cold for them to fly.
Loss of wetland habitat threatens dragonfly populations around the world.
At least one in ten species of dragonfly are threatened with extinction, according to the first world survey of their numbers.
In prehistoric times dragonflies were much larger, the largest flying insects ever. The largest member of extinct dragonflies had a wing span of about 75 centimeters (30 inches).
The oldest known species of dragonfly is the 320 million year old (Delitzschala bitterfeldensis).
Dragonflies are represented in human culture on artifacts such as pottery, rock paintings, and Art Nouveau jewellery.
They are used in traditional medicine in Japan and China, and caught for food in Indonesia.
They are symbols of courage, strength, and happiness in Japan, but seen as sinister in European folklore.
Some English vernacular names, such as “horse-stinger”, “devil’s darning needle”, and “ear cutter”, link them with evil or injury.
Swedish folklore holds that the devil uses dragonflies to weigh people’s souls.
For some Native American tribes, dragonflies represent swiftness and activity; for the Navajo, they symbolize pure water.