Dragonflies

The first of these (Anisoptera) includes the large, fast-flying dragonflies while the second (Zygoptera) covers the smaller, slower-flying damselflies.

There are approximately 3,600 known species of dragonfly in the world. In the British Isles there are 27 species of dragonfly and 16 species of damselfly.

Dragonflies are fast-flying, four-winged insects with long bodies and enormous eyes. The adult dragonfly has the biggest eyes in the insect world and they are capable of detecting movement up to 15m away! These fascinating and colourful creatures are among the fastest and oldest insects in the world. Their fossilised remains show that they were already here on earth 300 million years ago! For these reasons only the dragonflies are well worth studying and protecting.

All dragonflies are carnivorous in both the larval and adult stages of their lives. They feed on insect larvae and other smaller water dwellers up to the size of a large tadpole during the larval stage, and then graduate to most flying insects as adults.

Dragonflies may exist as larvae, or nymphs, from a few months up to five years, depending on the species. During this stage they live entirely under water, mostly in ponds, lakes and canals. The dragonfly's adult life lasts for little more than one month.

Male dragonflies have their own territory; they guard their particular stretch of water seeking prey, females and chasing off rivals.

There are two groups of dragonflies; one is known as hawkers: these have long, slim bodies and patrol up and down stretches of water, 'hawking' for prey. The other group is known as darters: these have smaller, fatter bodies than hawkers and spend most of their time clinging to waterside plants, occasionally darting out to catch a passing insect.

The Emperor dragonfly, Anax imperator, pictured on the front of this factsheet, has the largest wingspan of any British dragonfly - 10.5cm, and a body length of up to 8cm. (The Golden-ringed dragonfly, Cordulegaster boltonii, has the longest body length of all British dragonflies - up to 8.6cm).

The male emperor is a brilliant blue and the female is greenish - both have a black stripe down the back of the body. It is found in southern England and Wales, around large ponds, canals and lakes during the summer months. It is not found in Scotland or Ireland.

Dragonflies in Danger

Fifty years ago there were twice as many ponds in Britain as there are today. The draining of agricultural land, filling in and pollution have all contributed to the disappearance of most countryside ponds. Canals have also suffered from pollution, especially by chemicals used on farmland draining into water. The loss of suitable fresh water habitats has affected dragonflies enormously and they are becoming increasingly rare. The Norfolk aeshna, Aeshna isosceles, which can be found living only in the Norfolk Broads, is on the list of Britain's endangered species of insects.

Helping Dragonflies

Garden ponds have become very popular over recent years and these are helping to save Britain's threatened pond-life including dragonflies. Creating a pond habitat in your garden at home, or in your school grounds, is a practical and worthwhile conservation project.