Dragonfly

A dragonfly is a flying insect belonging to the suborder Anisoptera of the order Odonata. There are about 3,000 living species of dragonflies, most of which live in tropical areas, with fewer in temperate regions. Dragonflies are special because they have large, many-sided compound eyes, two pairs of strong, clear wings, and long bodies. Many dragonflies shine with bright, metallic colours that make them easy to see when they fly.

Dragonflies love to fly and are very good at catching other insects. They can fly very fast and accurately, sometimes even flying over oceans. They live near water and go through a stage called the nymphal stage, where they grow underwater before becoming adult dragonflies.

Dragonflies have been important in many cultures. People have made dragonflies on pottery, in paintings, and in jewellery. In some places, dragonflies are symbols of courage and happiness, while in others they are seen as mysterious. Their beautiful colours and quick flight have inspired many writers and artists.

Etymology

The name Anisoptera comes from Ancient Greek words. Anisos means "unequal" and pteron means "wing". It refers to the fact that dragonflies have broader hindwings compared to their front wings.

Evolution

Dragonflies are related to an ancient group called griffenflies, which lived about 325 million years ago in Europe. Some of these ancient insects were among the largest ever, with wingspans as wide as 30 inches. True dragonflies, known as Anisoptera, first appeared during the early part of the Jurassic period and have kept some traits from their ancient ancestors.

Today, there are around 3,000 different kinds of dragonflies found all over the world. They belong to a group called Palaeoptera, meaning 'ancient-winged', and unlike many modern insects, they cannot fold their wings against their bodies, though some have found their own special ways to do it.

Distribution and diversity

About 3,012 kinds of dragonflies were known in 2010. They live on every continent except Antarctica. Some dragonflies can be found in many places, like the blue-eyed darner, which lives across North America and Central America. Others, like the globe skimmer, can be found in warmer areas on all continents. Most dragonflies live in tropical areas, with fewer in colder regions.

Dragonflies can live in many different places, from sea level up to high mountains. Some live in desert pools and can survive in very hot temperatures. They become less common in very cold areas, like Iceland or northern Alaska, but sometimes strong winds can carry them to new places.

Description

Dragonflies are strong-flying insects with heavy bodies. They hold their wings out to the sides when they fly and when they rest. Unlike their relatives the damselflies, dragonflies do not fold their wings up when they are not flying.

An adult dragonfly has a head, a thorax (midsection), and an abdomen (tail section). The head is big and has two large eyes made up of many tiny parts that give them great vision. They also have three smaller simple eyes and mouthparts for biting. The thorax has three parts and holds the wings and legs. Dragonflies have two pairs of long, veined wings and three pairs of legs used mainly for catching prey and landing on plants. The abdomen is long and slender with ten sections.

Young dragonflies, called nymphs, look different from adults. They do not have wings or reproductive organs. They have a special lower jaw they use to catch food by snapping it out quickly. Some nymphs breathe through gills inside their bodies, while others use gills outside their bodies or a special tube to breathe underwater.

Biology

Dragonflies and damselflies are hunters both in their water-based young stages and as adults. The young, called nymphs, eat small water creatures, and bigger nymphs might even eat tadpoles or tiny fish. Some special nymphs can act like parasites, eating the gills of mussels.

Mating for dragonflies is complicated, with males and females transferring sperm in a special way. Males guard areas near water to protect their space and to find mates. Adult dragonflies often gather in groups to hunt flying insects like ants or termites.

Dragonflies live in many different places, from flowing rivers to still ponds. Some need specific plants or water conditions to survive. For example, one type lives only in swamps with a special plant, while others prefer acidic bogs or nutrient-rich waters.

Many dragonflies, especially males, protect certain areas. They fight for good spots to hunt or lay eggs, sometimes showing off bright colors or chasing rivals away. Females must mate with the male who owns the territory before laying eggs. Sometimes females act like males to avoid unwanted attention.

Mating involves a precise dance where the male picks up sperm and the pair flies together in a heart-shaped position. The female lays eggs either by slicing plants near water or by dropping them onto the water surface. Some eggs are laid above water and only develop when they sink later.

Dragonflies go through an incomplete metamorphosis, meaning they don’t have a pupal stage. Eggs hatch into nymphs that live underwater, hunting small creatures with their extendable jaws. After several molts, the nymph climbs out of the water, sheds its skin, and emerges as an adult.

Dragonflies are strong and agile fliers, able to move in any direction quickly. They can hover, fly fast, change direction suddenly, or even glide. Their wings beat in different patterns for different flying styles. They can reach speeds up to about 54 km/h (34 mph) and see very well, processing up to 200 images per second. Their vision covers almost a full circle, with most of their brain dedicated to seeing.

Predators

Dragonflies are fast and agile fliers, but some animals can still catch them. Birds like the American kestrel, the merlin, the hobby, nighthawks, swifts, flycatchers, and swallows sometimes eat dragonflies. Some wasps also hunt dragonflies, laying eggs on them to feed their young. In the water, animals such as ducks, herons, newts, frogs, fish, and water spiders eat young dragonflies, called nymphs. Amur falcons that migrate over the Indian Ocean may feed on dragonflies while flying.

Parasites

Dragonflies can be affected by three types of organisms that live on or in them: water mites, gregarine protozoa, and trematode flatworms (also called flukes). Water mites, called Hydracarina, can harm smaller dragonfly nymphs and sometimes appear on adult dragonflies. Gregarines infect the gut and might cause problems there. Trematodes are parasites of animals like frogs. They have complicated life cycles that may include a stage called a cercaria in a snail. Dragonfly nymphs can swallow these cercariae or they may pass through the nymph's body wall. Once inside, they form a cyst and stay there until the nymph grows into an adult. If a frog eats the infected nymph, the frog can become infected with the adult stage of the trematode.

Dragonflies and humans

Conservation

Many scientists who study dragonflies live in areas with colder winters, so most research has focused on dragonflies in places like North America and Europe. However, most dragonfly species live in tropical areas, where they haven't been studied as much. As forests are cut down, many dragonflies are in danger of disappearing before we even know they exist. This happens because their homes, like streams and pools, dry up or get filled with dirt.

Efforts are being made to protect dragonflies by creating special areas where they can live safely. These areas help keep their habitats healthy. There is also a need for more research and ways to reduce pollution to help dragonflies survive.

In culture

Dragonflies have been important in many cultures. In ancient Egypt, people made dragonfly-shaped decorations. For the Navajo and other Native American groups, dragonflies represent clean water. In Japan, dragonflies are linked to autumn and are seen as symbols of strength and happiness. They appear often in Japanese art and poetry.

In Europe, some old stories thought dragonflies were scary or evil, giving them names like "devil's darning needle." But today, many people enjoy watching dragonflies, and they are popular in art and design.

In poetry and literature

Writers and poets have often used dragonflies in their work. Japanese poets wrote many poems, called haiku, about dragonflies. Famous poets like Matsuo Bashō wrote beautiful lines comparing dragonflies to autumn. In Europe, poets like Lord Tennyson described dragonflies in their poems, comparing their shiny wings to sapphire.

In technology

Scientists have made dragonflies able to follow light signals by adding tiny sensors and a small computer to their bodies. This lets the dragonflies act like tiny flying machines that can be controlled with light, which could be useful for many purposes.