Emperor Dragonfly - Anax imperator

Adult size

Overall length: 64 - 84mm   Hindwing length: 45 - 51mm

Distinguishing features

Britain’s largest, heaviest and most impressive dragonfly. An early summer species. The brightly coloured turquoise and apple green males coupled with their aggressive territorial behaviour make this one of most well known and easily recognisable dragonflies. 

Identification - for help with terms see glossary

Mature males

Are a bright sky-turquoise blue colour with an irregular dark line down the centre of its abdomen. This bright colour will fade in cool conditions. The thorax is bright apple green, easily viewed from the side. Eyes and face are bright blue. Tends to droop its abdomen in flight, slightly banana shaped.

Immature males

Resemble pale females, with pale brown markings on the abdomen, green thorax and yellow-green eyes.

Mature females

Resemble the males with identical markings, the colour of the abdomen is green, the central line dark brown. However, in warm conditions the abdomen will become blue resembling a male. Thorax is apple green. Eyes are yellow-green but can also be blue.

Immature females

Resemble mature females with more muted drab colours. Thorax is pale green and eyes pale yellow-brown.

Habitat

Mostly associated with large, well vegetated ponds and lakes, but may be found over canals and slow moving rivers. Common in garden ponds.

Behaviour

Visit any decent sized pond in early summer and you will probably encounter a male Emperor patrolling it. They are very territorial and will chase other males and investigate other species. Will fly away from water however to hunt. Females are often visible laying eggs on floating vegetation and will do so alone.

Status and distribution

Very common in southern and central England and south Wales. Slowly spreading northwards and westwards. Common and widespread in Dorset.


 

Flight period

Main flight period is May to September, peaking between mid June to mid August.

Similar species

The bright unique colouring and patterns of the adults & aggressive behaviour of the males make this species very distinctive. Only confusion could be with rare migrant Lesser Emperor.

More photographs

Click on the photos below to enlarge...

All photographs by kind permission & © of Ken Dolbear unless otherwise stated. All rights reserved.