Steven Cheshire's British Butterflies
British Butterflies: Species: Species Account - The Purple Emperor:
Purple Emperor
Apatura iris (Linnaeus, 1758)

Purple Emperor egg.
  Purple Emperor caterpillar.
  Purple Emperor chrysalis
Purple Emperor
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Insecta: Lepidoptera : Family Nymphalidae: Subfamily Apaturinae : Genus Apatura: Species iris:
Probably the most magnificent butterfly to be seen in Britain the Purple Emperor is an enigmatic butterfly and is the second largest in Britain... only the Swallowtail being larger. It is rarely seen unless a special effort is made to find it although there are some key sites in the UK where those interested in butterflies make a pilgrimage to see this species.

The deep purple colouration of the male Purple Emperor is a result of light refraction by ridges on the wing scales. It is only visible from certain angles depending upon the direction of light. The females lack this colouration being primarily dark grey-brown but with larger eye spots towards the rear of the hind wings. Both sexes have a broken flash of white across the forewings. The underside has a large eyespot used to deter predators.

It flies high in the tree-tops of woodland in central-southern England where it feeds on aphid honeydew and sap runs. They never visit flowers to feed. It is often seen soaring in circles and can be confused with
White Admirals. Adult butterflies are extremely elusive and occur in low numbers over large areas. The males sometimes occur on the ground feeding on salts either from path and road surfaces or from animal dung. To see the Purple Emperor on the ground normally requires an early start... they are often seen on clear warm sunny days as early as 8am but can also be seen late in the afternoon / early evening.

The males are known to travel more than 1000 metres from their breeding areas, gathering in what are known as master trees (usually mature Oaks, but Beech, Aspen and Conifers are sometimes used) where the males compete for females which are seen less often. After mating, the females disperse to lay their eggs.
The Purple Emperor occurs in expansive broad-leaved woodland or in areas where there are clusters of smaller wooded areas where the larval foodplant is abundant.
The Purple Emperor declined steadily during the twentieth century and is now restricted to some of the larger woods in southern England. There has been a recent slight re-expansion in some areas.
Where to see the Purple Emperor in the British Isles

The Purple Emperor declined steadily during the twentieth century and is now restricted to some of the larger woods in southern England. There has been a recent slight re-expansion in some areas.

Fermyn Wood in Northamptonshire is visited by many butterfly enthusiasts during the summer months as the Purple Emperor occurs here in good numbers. The Purple Emperor is present here thanks to the work of author, artist and conservationist Denys Watkins-Pitchford MBE (aka 'BB') who bred and released some of these butterflies at Fermyn having first seen the butterfly as a child at nearby Salcey Forest. 'BB' died in 1990 age 85.

Fermyn is probably one of the best sites in the UK to see this species although best avoided during the weekend when the Paparazzi turn up... sadly Fermyn is quickly going the way of Collared Hill where  a small minority of photographers lack even basic common sense and courtesy to others.

Other sites include: Savernake Forest, Wiltshire.

Other notes
Lifecycle chart
Flight chart
The lifecycle and flight charts should be regarded as approximate guides to the Purple Emperor in Britain. Specific lifecycle states, adult emergence and peak flight times vary from year to year due to variations in weather conditions.
IUCN category status 2010 5   IUCN category status 2007 34
--awaiting data-- --awaiting data--

5Fox, R., Warren, M., Brereton, T. M., Roy, D. B. & Robinson, A.
(2010) A new Red List of British Butterflies. Insect Conservation and Diversity.
Near Threatened Near Threatened

3Fox, R., Warren, M & Brereton, T.
(2007) New Red List of British Butterflies. Butterfly Conservation, Wareham.

4More information about IUCN categories.
UK status
Larval foodplants
Goat Willow (Salix caprea) also known as Sallow or Pussy Willow is the primary larval foodplant although Grey Willow (Salix cinerea) and Crack Willow (Salix fragilis) is also used.

The Purple Emperor lays its eggs on a wide range of tree sizes. The eggs are laid singly on the upperside on the leaves of broad-leaved sallows which are preferred to narrow-leaved varieties.
Butterflies of Britain ID Chart
Your personal guide to British Butterflies. This 8-panel laminated chart is designed for speedy butterfly identification in the field. Ideal for anyone interested in identifying butterflies, perfect for children and adults and ideal for outdoor use, laminated, shower-proof and robust. Get your copy today.
Butterflies of Britain (Laminated ID Chart).
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Visit our online store for many more butterfly related books and gifts.
Population trends 1
UK Population trend 1995-2004 up by 33%
UK Population trend 1976-2004 down by -18%

1Fox, R., Asher. J., Brereton. T., Roy, D & Warren, M. (2006) The State of Butterflies in Britain & Ireland, Pices, Oxford.
UK BAP status 2
UK BAP status species of conservation concern (link)

2For information about the UK Biodiversity Action Plan, visit the JNCC web site

National Biodiversity Network Gateway
National Biodiversity Network Gateway Distribution Map

Areas in and indicate a contraction in distribution of the Purple Emperor except in Ireland where data is only available up until 1999.

* Records shown in outside the natural distribution may be the result of illegal or accidental releases by breeders or, depending upon the species, migrant individuals from mainland Europe.

Key to map*
= 2000 to 2010 inclusive (current distribution)
= records from 1950 to 1999 inclusive
= records from 1900 to 1949 inclusive
Records prior to 1st January 1900 are not shown.

The NBN Gateway records are shown on the map right. (See terms and conditions).

More data is available on the Purple Emperor on the NBN Gateway web site.
Powered by NBN Gateway.
For full details of books and reports mentioned on this web site, view the references page.

Find out more online*
Purple Emperor can be found on Peter Eeles excellent UK Butterflies web site.
Purple Emperor can be found on Matt Rowlings excellent European Butterflies web site.

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Photographs of the Purple Emperor
Image ID BB2236 - Purple Emperor - © Steven Cheshire
Purple Emperor male (imago)
BB2236 ©
Image ID BB2235 - Purple Emperor - © Steven Cheshire
Purple Emperor male (imago)
BB2235 ©
Image ID BB2234 - Purple Emperor - © Steven Cheshire
Purple Emperor male (imago)
BB2234 ©
Image ID BB1850 - Purple Emperor - © Steven Cheshire
Purple Emperor male (imago)
BB1850 ©
Image ID BB1849 - Purple Emperor - © Steven Cheshire
Purple Emperor (imago)
BB1849 ©
Image ID BB1848 - Purple Emperor - © Steven Cheshire
Purple Emperor (imago)
BB1848 ©
Image ID BB1847 - Purple Emperor - © Steven Cheshire
Purple Emperor (imago)
BB1847 ©
Image ID BB1846 - Purple Emperor - © Steven Cheshire
Purple Emperor (imago)
BB1846 ©
Image ID BB1845 - Purple Emperor - © Steven Cheshire
Purple Emperor (imago)
BB1845 ©
Image ID BB1844 - Purple Emperor - © Steven Cheshire
Purple Emperor (imago)
BB1844 ©
There are 27 photographs of the Purple Emperor in our stock photo library.
View more photographs of the Purple Emperor as a thumbnail gallery or as a slideshow.
Aberrations and forms
There are 8 named aberrant forms of the Purple Emperor currently listed. Find out more about aberrants here.

ab. chattendeni - Heslop & Stockley 1961
ab. deschangei - Cabeau 1910
ab. iolata - Cabeau 1910
ab. iole - [Denis & Schiffermüller] 1775
ab. lugenda - Cabeau 1910
ab. monophana - Cabeau 1919
ab. obscura - Sälzl 1916
ab. stictica - Cabeau 1910