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!
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.
Having emerged, the adult dragonfly must cling to the plant stem for about two hours, during which time the body and wings harden in readiness for flight.
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, 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.Read More: Dragon Flies in Danger