Purple Emperor

Apatura iris (a-pa-TOO-ruh EYE-riss)

Purple Emperor - Fermyn Wood 2-July-2014
Photo © Neil Hulme
 

Wingspan
70 - 92mm

Checklist Number
59.022

Family:NymphalidaeRafinesque, 1815
Subfamily:ApaturinaeBoisduval, 1840
Tribe:ApaturiniBoisduval, 1840
Genus:ApaturaFabricius, 1807
Subgenus:  
Species:iris(Linnaeus, 1758)

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Introduction

The Purple Emperor is a magnificent and elusive insect that is actively sought out by the many subjects of "His Majesty", as the male butterfly is affectionately known. This butterfly spends most of its time in the woodland canopy where it feeds on aphid honeydew, with the occasional close encounter when it comes down to feed on sap runs or, in the case of the male, animal droppings, carrion or moist ground that provide much-needed salts and minerals. Those that make pilgrimages to see this spectacular creature will often try and lure the males down from the canopy using all manner of temptations - including banana skins and shrimp paste.

The male butterfly is one of the most beautiful of all of the butterflies found in the British Isles. From certain angles it appears to have black wings intersected with white bands. However, when the wings are at a certain angle to the sun, the most beautiful purple sheen is displayed, a result of light being refracted from the structures of the wing scales. The female, on the other hand, is a deep brown and does not possess the purple sheen found in the male.

This is one of the most-widely studied and written about butterflies in the British Isles. The classic work "Notes and Views of the Purple Emperor" by Heslop, Hyde and Stockley is dedicated to this butterfly, as is the modern-day equivalent - the excellent website The Purple Empire. This butterfly is confined to deciduous woodland in central southern England, between South Wiltshire and South Hampshire in the west, Surrey and West Sussex in the east, and Oxfordshire and Hertfordshire in the north, with scattered colonies elsewhere. It is not found in the north of England, Scotland, Ireland, the Isle of Man or the Channel Islands and has not been seen in Wales since the 1930s. Colonies vary in size, some being very small with just a dozen or so adults forming a viable colony.

Apatura iris

This species was first defined in Linnaeus (1758) as shown here (type locality: Germany, England etc.).

Purple Emperor, Botany Bay, 28 June 2009

Male
Photo © Neil Hulme

Purple Emperor - Fermyn Woods - 14.07.13

Male Underside
Photo © Rosalyn

Purple Emperor (female), Chiddingfold Forest (17 July 2013)

Female
Photo © Mark Colvin

Purple Emperor (female) Bernwood Forest Oxfordshire 4th July 2011

Female Underside
Photo © millerd

Photo Album ...


History

The table below shows a chronology of vernacular names attributed to this species. Any qualification of the name (e.g. male, female) is shown in brackets after the name.

YearNameReference
1704Mr. Dale's Purple EyePetiver (1702-1706)
1742Purple EmperorWilkes (1742)
1749Purple HighflyerWilkes (1749)
1749Emperor of the WoodsWilkes (1749)
1795Purple ShadesLewin (1795)
1832EmperorRennie (1832)
1853Emperor of MoroccoMorris (1853)

Conservation Status

Determining the status of this species has always been problematic given its elusive nature and, although its status is considered relatively-stable, is still considered a species of conservation concern.

UK BAP StatusOccurrence Change
1976-2014 (%)
Abundance Change
1976-2014 (%)
Occurrence Change
2005-2014 (%)
Abundance Change
2005-2014 (%)
Species of Conservation Concern
Decrease-47
Large Increase+69
Large Increase+135
Decrease-35

The table above shows the occurrence (distribution) and abundance (population) trends, using information from The State of the UK's Butterflies 2015 (Fox, 2015). Any UK BAP status is taken from the UK Biodiversity Action Plan (UK BAP) (2007 review).

Habitat

This is a butterfly of large expanses of deciduous woodland, usually those containing oaks, but less-frequently beech and other species.

Distribution

 

Click here to see the distribution of this species or here to see the distribution of this species together with specific site information overlaid.

Life Cycle

There is a single generation each year. The adult butterfly emerges in early July, sometimes at the end of June in good years, with a peak in the second and third weeks of July.

The chart(s) above have been correlated with the phenology plot below, taken from the UK Butterfly Monitoring Scheme. The blue line gives average counts over the full data set from 1976 to date, and the red line gives the average for the last year.

 

Imago

This species is best seen in early morning and again in late afternoon, when the males will come down to the ground to feed on moisture from damp earth and animal droppings. The males are sometimes so engrossed in feeding that they will spend over an hour feeding in the same place, each displaying its characteristic yellow proboscis. The males are also notorious for feeding on mud and other debris that has gathered on surfaces of cars parked within the woodland. They are also partial to sweat and readily land on observers. However, both male and female spend the majority of their time resting high in the tree canopy and out of sight.

In late morning, the males will fly off and ultimately congregate at so-called "master trees" that provide a vantage point for intercepting passing females. These trees are typically at a high point in the wood, such as trees growing on the summit of a hill, and the same trees are used year after year. Locating a master tree is one of the best ways to catch a glimpse of this elusive insect. Seeing the males battle it out for the best vantage points, with flashes of purple as the light hits their wings, is an amazing spectacle.

When a virgin female is encountered, the pair fly off and settle in the canopy where mating takes place. If the female has already mated, then she has the curious habit of descending straight to the ground, where the male ultimately loses interest and returns to his perch.

Adults feed primarily on Honeydew / Sap. Carrion and Dung are also used.

Apatura iris

Male Purple Emperor, Alice Holt, 21 July 2012

Photo © Pauline
21-Jul-2012

Purple Emperor, Botany Bay, 28 June 2009

Photo © Neil Hulme
28-Jun-2009

Male Purple Emperor, Alice Holt, 25/07/2012

Photo © Pauline
25-Jul-2012

Purple Emperor - imago - Thatcham - 24-Jun-04 (02) [REARED]

Photo © Pete Eeles
24-Jun-2004

Purple Emperor - imago - Thatcham - 29-Jun-11 (1) {REARED}

Photo © Pete Eeles

Purple Emperor - imago - Thatcham - 26-Jun-11 (1) {REARED}

Photo © Pete Eeles

Purple Emperor - male - Fermyn Wood, Northants - 17-Jul-13-6

Photo © Pete Eeles
17-Jul-2013

Purple Emperor - imago - Thatcham - 28-Jun-10 (9) {REARED}

Photo © Pete Eeles
28-Jun-2010

Purple Emperor - imago - Tajvedelmi, Hungary - 14-Jul-06 (0552)

Photo © Pete Eeles
14-Jul-2006

Purple Emperors sparring - Bookham Common, Surrey Aug-2013[Rob Hill]09

Photo © Rob Hill

Purple Emperor - imago - Thatcham - 28-Jun-10 (2) {REARED}

Photo © Pete Eeles
28-Jun-2010

Purple Emperor - Fermyn Woods - 14.07.13

Photo © Rosalyn
14-Jul-2013

Purple Emperor - imago - Thatcham - 24-Jun-04 (07) [REARED]

Photo © Pete Eeles
24-Jun-2004

Purple Emperor - Fermyn Woods - 14.07.13

Photo © Rosalyn
14-Jul-2013

Purple Emperor - male - Thatcham - 13-Jun-14 [REARED]-5

Photo © Pete Eeles
13-Jun-2014

Purple Emperor - male - Thatcham - 13-Jun-14 [REARED]

Photo © Pete Eeles
13-Jun-2014

Purple-Emperor- 5D32031 Hants July 2015

Photo © IainLeach

Purple Emperor (female) - Fermyn Wood - 18th - July - 2016

Photo © Maximus
18-Jul-2016

Purple Emperors sparring - Bookham Common, Surrey Aug-2013 [Rob Hill]05

Photo © Rob Hill

Purple Emperor - imago - Thatcham - 16-Jun-04 (10) [REARED]

Photo © Pete Eeles
16-Jun-2004

Photo Album (77 photos) ...


Ovum

When egg-laying, the female "strikes" the sallow, as it is known, where she enters the tree and disappears within to lay a single egg on the upperside of a sallow leaf that is in half-shade. Eggs are usually laid on leaves toward the crown of the tree at various heights. Eggs are blue-green when first laid but, after a few days, the base of the egg turns purple giving the egg a distinct 2-tone appearance. Eggs hatch in 9 or 10 days, depending on the weather.

"A female captured in the New Forest, August 2nd, 1902, was enclosed on a small bush of sallow (Salix caprea). On August 7th, during a short spell of sunshine, she deposited thirteen eggs, only one on each leaf, and usually near the base. Owing to continuous dull, cold weather no more eggs were laid, and the female died on August 13th. In a wild state the eggs are always laid on the upper surface of the leaves of sallow. When about to lay the female iris flies boldly into a sallow bush, disappearing from view. If carefully watched it can be observed crawling about on the inner branches of the bush, presumably depositing. New Forest collectors call the act of a female Purple Emperor when it dashes into a sallow bush "striking the tree," so violent is its action. In depositing the butterfly settles on a leaf, then lowers abdomen so that the extremity rests on the upper surface, and, after remaining motionless for eight or ten seconds, lays an egg and flies off. The egg measures 1 mm. high, and the same in width. It is of a blunt conical shape, widest at the base, which is rounded and embedded in glutin. The micropyle is finely reticulated, from which run fourteen longitudinal keels down to the base. The spaces between are concave and finely reticulated, and are developed into fine transverse ribs towards the base. The keels are of curious construction, each being formed of three very fine, serrated longitudinal ridges; the two outer ones are united at each end. When first laid it is uniformly of an ochreous-green colour. On the fifth day a dull purplish irregular zone encircles it just above the base. The ground colour remains unchanged. When ten days old it is of a more opaque ochreous, and the zone darker, which disappears on the eleventh day, and the head of the larva shows dark leaden under the crown. This finally becomes blackish, and the egg hatches on the fourteenth day." - Frohawk (1924)

Purple Emperor egg, recently laid, Southwater Woods, 8 July 2007

Photo © Neil Hulme
08-Jul-2007

Purple Emperor egg, well developed, Southwater Woods, 13 July 2007

Photo © Neil Hulme
13-Jul-2007

Purple Emperor egg, August 2010, Switzerland

Photo © Padfield
Switzerland

Purple Emperor - ovum - Wiltshire Wood - 23-Aug-13

Photo © Pete Eeles
23-Aug-2013

Purple Emperor - ovum - Wiltshire Wood - 25-Aug-13

Photo © Pete Eeles
25-Aug-2013

Purple Emperor ovum - Rockingham Forest 08.07.14.

Photo © Tony Moore
09-Jul-2014

Freshly laid egg, Switzerland, July 27th 2014

Photo © Padfield
Recently laid wild purple emperor egg, found on July 27th in Switzerland.
27-Jul-2014

Purple Emperor - ovum - Savernake Forest, Wiltshire - 24-Jul14-2

Photo © Pete Eeles
24-Jul-2014

Purple Emperor - ovum - Savernake Forest, Wiltshire - 24-Jul14

Photo © Pete Eeles
24-Jul-2014

Purple Emperor - ovum - Savernake Forest, Wiltshire - 26-Jul-14-2

Photo © Pete Eeles
26-Jul-2014

Purple Emperor - ovum - Savernake Forest, Wiltshire - 26-Jul-14

Photo © Pete Eeles
26-Jul-2014

Purple Emperor - ovum - Savernake Forest, Wiltshire - 27-Jul-14

Photo © Pete Eeles
27-Jul-2014

Purple Emperor ovum - Switzerland 22-July-2016

Photo © Padfield
22-Jul-2016

Purple Emperor ovum - Knepp Estate, Sussex 15-July-2016

Photo © Neil Hulme
15-Jul-2016

Purple Emperor ovum (6 days old) - Switzerland 1-Aug-2016

Photo © Padfield
01-Aug-2016

Purple Emperor ovum (1 day old) - Switzerland 27-July-2016

Photo © Padfield
27-Jul-2016

Purple Emperor ovum (7 days old) - Switzerland 2-Aug-2016

Photo © Padfield
02-Aug-2016

Purple Emperor ovum (9 days old) - Switzerland 3-Aug-2016

Photo © Padfield
03-Aug-2016

Purple Emperor ovum - Knepp, Sussex 30-June-2017

Photo © Neil Hulme
30-Jun-2017

Photo Album (19 photos) ...


Larva

On hatching, the green larva eats its eggshell before moving to the tip of the Sallow leaf, where it rests facing the leaf stalk. It feeds by day on each side of its resting place, leaving characteristic feeding damage. After the first moult, the larva is a curious beast, being adorned with 2 horns that grow out of the head. After the second moult the larva turns light brown and moves to the fork of a twig or next to a Sallow bud, where it overwinters on a silk pad with its body flush against the surface on which it is lying.

Larvae emerge from hibernation around the middle of April just as the Sallow buds are starting to expand. The larva initially feeds on the unfurling buds, until the leaves are fully-developed. The larva will then rest on a particular Sallow leaf, which is always left intact, and from which it travels to feed, returning after it has completed its meal. When at rest, the larva also sits with the front of its body slightly raised off its leaf thereby minimising any shadow that might give its presence away. It is also beautifully camouflaged with several subtle yellow stripes along the length of its body that perfectly match those of pale veins of the Sallow leaf on which it sits.

When ready to pupate, the larva travels to find a suitable pupation site, and turns a much paler green. The larva will move to the underside of the chosen Sallow leaf and spend 1 or 2 days building a pad of silk from which the pupa will be suspended. At first, the larva rests with its head facing the leaf stalk. As the time for pupation nears, the larva reverses this position, with its head facing the leaf tip. The larva has 5 instars in total.

The primary larval foodplant is Goat Willow (Salix caprea). Crack-willow (Salix fragilis) and Grey Willow (Salix cinerea) are also used.

1st Instar

"The larva eats round the egg just below the crown, leaving only two or three of the ribs attaching it to the rest of the shell, which forms a lid. The larva then forces it open, and crawls out, the lid falling into place again. Directly after emergence the larva measures 3.2 mm. long. The head is globular and very large in proportion to the body, being about twice its diameter. The surface is covered with raised reticulations, forming a network pattern of an ochreous-yellow, and a large patch of the same colour on the crown of each lobe. The remainder of the surface is shining black; the reticulations give it a dull, roughened appearance when viewed under a lens. The mouth parts are black and amber, with a few whitish hairs on the face. The body is wrinkled transversely with five sub-divisions on each segment; on each side above the spiracles are three longitudinal rows of short, club-like, glassy white tubercles; two, on the dorsal surface, have black bases, the other, above the spiracles, is quite white. On the lateral fold on each segment are two clubbed hairs, and on the claspers are two sharply pointed hairs or spines, all of pearly whiteness. The spiracles are pale and inconspicuous, excepting the first and last, which are large and prominent. The anal segment has two projecting points, each terminating in a single white hair. The ground colour is a light greenish-yellow with greyish-green mottlings along the side, and speckled with rust-brown spots, which form a medio-dorsal line, and a checkered pattern along the sides; the whole surface is granular; the ventral surface, including the claspers, is paler. Shortly before first moult it measures 4.8 mm. long. The ground colour is green, checkered with paler green and striped obliquely with pale lemon-yellow, the fifth stripe being the yellowest and most distinct. These are broken up by the segmental divisions. There is a decided green medio-dorsal longitudinal stripe and a whitish lateral stripe; the anal points are dull pink. During the first stage, which lasted nine days, the larva made 245 excrements. The larva fixed for moulting when nine days old. During its first stage it rests in a straight position at the top of the leaf along the midrib, upon which a layer of silk is spun. It feeds at the edge of the leaf, eating the entire structure, and after each meal crawls back to its resting-place." - Frohawk (1924)

Purple emperor, 1st instar larva, day 13 Switzerland 23-Aug-2012

Photo © Padfield
1st instar larva on final day, immediately prior to ecdysis
23-Aug-2012

Purple Emperor - larva - Wiltshire Wood - 23-Aug-13

Photo © Pete Eeles
23-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 23-Aug-13-2

Photo © Pete Eeles
23-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 24-Aug-13

Photo © Pete Eeles
24-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 24-Aug-13-4

Photo © Pete Eeles
24-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 24-Aug-13-5

Photo © Pete Eeles
24-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 25-Aug-13-6

Photo © Pete Eeles
25-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 30-Aug-13 (1) [REARED]

Photo © Pete Eeles
30-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 30-Aug-13 (2) [REARED]

Photo © Pete Eeles
30-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 30-Aug-13 (3) [REARED]

Photo © Pete Eeles
30-Aug-2013

Purple Emperor - larva (1st instar) - Savernake Forest - 03-Aug-14

Photo © Pete Eeles
03-Aug-2014

Purple Emperor - larva (1st instar) - Savernake Forest - 05-Aug-14

Photo © Pete Eeles
05-Aug-2014

Purple Emperor - larva (1st instar) - Savernake Forest - 30-Jul-14-2

Photo © Pete Eeles
30-Jul-2014

Purple Emperor - larva (1st instar) - Savernake Forest - 30-Jul-14

Photo © Pete Eeles
30-Jul-2014

Purple Emperor larva (newly emerged) - Switzerland 6-Aug-2016

Photo © Padfield
06-Aug-2016

Photo Album (15 photos) ...


2nd Instar

"The first moult took place on August 31st (evening). It ate part of its cast skin the following day. The moulting process is very slow, occupying about three days, and it rests for another day after the moult. The first one, which was kept indoors, moulted the second time on September 16th. Some of the others, out of doors, had fixed themselves for moulting on September 20th. Before the second moult it measures 7.6 mm. long, exclusive of the horns, which measure 1.8 mm. The body is green, wrinkled transversely, and the segmental divisions clearly defined, anal points ochreous. The whole surface above the spiracles is sprinkled with minute black spines, having whitish swollen bases. Below the spiracular line the spines are longer and wholly white, the spiracles are small, indistinct, but prominent green with blackish apertures. The entire surface is granular. There are nine oblique yellowish side stripes; the first two are short and indistinct, the fifth being most prominent, and united on the back by a triangular yellow blotch on which are two large yellow warts placed on the first wrinkle of the seventh segment. These are represented on the other segments by much smaller ones. There is a fine medio-dorsal line separating the oblique markings. The head is furnished with two horns diverging in the form of a V, the tips are knobbed and cleft. They are densely covered with tubercles, each emitting a fine, long, whitish hair. They decrease in length on nearing the head, where they form short spines. The head is very rough, the tubercles being small and crowded together. Both head and horns vary somewhat in colour, but generally they are dull ochreous-brown. While the larva is resting the head is lowered so that the horns project straight in front, but when walking it closely resembles a slug, carrying its horns elevated, and the body is tapering like a slug." - Frohawk (1924)

Purple Emperor larva, second instar - Switzerland 24-Aug-2012

Photo © Padfield
Switzerland
24-Aug-2012

Purple Emperor - larva - Wiltshire Wood - 24-Aug-13-6

Photo © Pete Eeles
24-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 25-Aug-13

Photo © Pete Eeles
25-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 25-Aug-13-7

Photo © Pete Eeles
25-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 25-Aug-13-8

Photo © Pete Eeles
25-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 25-Aug-13-9

Photo © Pete Eeles
25-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 25-Aug-13-10

Photo © Pete Eeles
25-Aug-2013

Purple Emperor - larva - Wiltshire Wood - 30-Aug-13 (4) [REARED]

Photo © Pete Eeles
30-Aug-2013

Purple Emperor - larva (2nd instar) - Wiltshire Wood - 23-Sep-13

Photo © Pete Eeles
23-Sep-2013

Purple Emperor - larva (2nd instar) - Savernake Forest - 09-Aug-14

Photo © Pete Eeles
09-Aug-2014

Photo Album (10 photos) ...


3rd Instar

"After second moult, fifty days old, it is 10.5 mm. in length, exclusive of head and horns, which measure 2.5 mm. It is of similar form, pattern and colouration to previous stage, excepting the horns are not cleft, but terminate in a simple, rounded, shining, rust-red knob; the anal points are united, having only a groove down the centre forming one point, pinkish on the dorsal surface and white below. Whenever it crawled from one leaf to another it rapidly spun a network of silk on the surface to form a foothold. It always rests upon a layer of silk in a straight position, with its horns projecting in front in a line with the body; the anterior portion of the body is slightly raised, resting only by its claspers. The larvae entered into hibernation between October 15th and 20th; all eight specimens spun a quantity of silk round the stalks of the leaves, binding them to the stems, thus securing the leaves from falling; they also spun over the whole of the stalk and a layer along the upper surface of the leaf near the base, upon which part they settle down for hibernation. All excepting one did the same. The larva lies along the midrib with the anal point at the stalk and the head projecting towards the tip of the leaf. Whatever form the leaf takes, whether curling up or down, the larva bends with it so as to lie flat on the surface, with its head pressed down on the leaf. Soon after settling down to hibernation, the larva gradually changes in colour with the change of colour in the decaying leaf. The larva also hibernates at the fork of a branch, where it spins a layer of silk to rest upon, in the same attitude as it assumes when hibernating on a leaf. The green of the larva gradually becomes ochreous, and finally assumes a pale olive ground colour. The dorsal surface is whitish-ochreous, mottled with olive and reddish; the yellow stripes are replaced by lilac-pink and the dorsal warts are rust-red, the anal point also reddish; the rough surface, composed of tiny spines, giving it a downy appearance which very closely resembles the rough downy surface of the leaf. The colouring of both larva and leaf are so similar that the former is wonderfully disguised. While hibernating it measures 9 mm. in length. Early in March, before leaving its hibernaculum, the larva gradually assumes a greener hue, which increases in depth as the sallow buds develop; the elongated buds closely resemble the larva. They left their hibernacula during the last few days of March, 1903, and soon after commenced feeding on the young tender leaves, and gradually became a clearer green, exactly similar to what they were previous to hibernation, but the yellow oblique stripes are now white, and the dorsal central points are pale and inconspicuous. Before third moult it measures 12.7 mm. long." - Frohawk (1924)

Purple Emperor - larva (3rd instar) - Wiltshire Wood - 03-Nov-13-15

Photo © Pete Eeles
03-Nov-2013

Purple Emperor - larva (3rd instar) - Wiltshire Wood - 03-Nov-13-14

Photo © Pete Eeles
03-Nov-2013

Purple Emperor - larva 3rd instar - Wiltshire Wood - 30-Nov-13-10

Photo © Pete Eeles
30-Nov-2013

Purple Emperor - larva 3rd instar - Wiltshire Wood - 30-Nov-13-8

Photo © Pete Eeles
30-Nov-2013

Purple Emperor larva 4, pre-hibernation, Wilts Wood, 11 October 2009

Photo © Neil Hulme
11-Oct-2009

Purple Emperor larva 2, pre-hibernation, Wilts Wood, 11 October 2009

Photo © Neil Hulme
11-Oct-2009

Purple Emperor - larva 3rd instar - Wiltshire Wood - 10-Mar-14-7

Photo © Pete Eeles
10-Mar-2014

Purple Emperor - larva 3rd instar - Wiltshire Wood - 30-Nov-13-6

Photo © Pete Eeles
30-Nov-2013

Purple Emperor - larva - Thatcham - 31-Mar-11 (1) {REARED}

Photo © Pete Eeles

Purple Emperor - larva 3rd instar - Wiltshire Wood - 31-Mar-14

Photo © Pete Eeles
27-Mar-2014

Purple Emperor - larva 3rd instar - Wiltshire Wood - 10-Mar-14-9

Photo © Pete Eeles
10-Mar-2014

Purple Emperor - larva (3rd instar) - Wiltshire Wood - 23-Sep-13-6

Photo © Pete Eeles
23-Sep-2013

Purple Emperor - larva (3rd instar) - Wiltshire Wood - 03-Nov-13-18

Photo © Pete Eeles
03-Nov-2013

Purple Emperor - larva (3rd instar) - Savernake Forest - 21-Apr-14

Photo © Pete Eeles
21-Apr-2014

Purple Emperor - larva 3rd instar - Wiltshire Wood - 10-Mar-14-10

Photo © Pete Eeles
10-Mar-2014

Purple Emperor larva 5, pre-hibernation, Wilts Wood, 11 October 2009

Photo © Neil Hulme
11-Oct-2009

Purple Emperor - larva (3rd instar) - Thatcham - 17-Apr-14 [REARED]

Photo © Pete Eeles
17-Apr-2014

Purple Emperor - larva (3rd instar) - Wiltshire Wood - 04-Oct-13-2

Photo © Pete Eeles
04-Oct-2013

Purple Emperor hibernating larva 1, Wiltshire wood, 10 January 2010

Photo © Neil Hulme
10-Jan-2010

Purple Emperor - larva (3rd instar) - Wiltshire Wood - 23-Sep-13-4

Photo © Pete Eeles
23-Sep-2013

Photo Album (43 photos) ...


4th Instar

"Two moulted the third time on May 6th, 1903; others fixed for moulting same time. After third moult, 275 days old, and shortly before fourth moult, it is 19 mm. in length, exclusive of the horns, which are 3.5 mm. long; there is no particular difference in this stage from the previous one, and its habits are similar." - Frohawk (1924)

Purple Emperor - larva - Thatcham - 20-Apr-11 (2) {REARED}

Photo © Pete Eeles

Purple Emperor - larva (4th instar) - Savernake Forest - 21-Apr-14

Photo © Pete Eeles
21-Apr-2014

Purple Emperor - larva (4th instar) - Thatcham - 17-Apr-14 [REARED]

Photo © Pete Eeles
17-Apr-2014

Photo Album (3 photos) ...


5th Instar

"The fourth moult occurred on May 22nd, 1903. The cast skin is not now eaten. After fourth moult, 290 days old, and fully grown, it measures while crawling 44 mm. in length, and 38 mm. at rest. The general shape is very slug-like, being attenuated at either end. The head is furnished with a pair of horns shaped very much like those of a slug; they are 6.3 mm. long, tapering gently, with slightly cleft, knobbed apices. They are immovable, being elongations of the notched crown. Both head and horns are thickly sprinkled with raised points, each emitting a fine whitish hair, longest on the horns, especially on the tips. The points are white, excepting some on the basal portion of the horns, which are longer and shining black. There are also a few black dots on the side of the head, and black eye spots. The apical knobs are deep rust colour, the head and horns are light greenish-blue, with a whitish stripe along the upper side of the latter and a white band down each check. The body has a finely granulated surface, and is sprinkled all over with whitish points. Those on the dorsal surface bear a very minute black spine; those on the lateral surface are paler, and along the lateral ridge the points terminate in white hairs, which are very fine and have the appearance of down to the naked eye. The ventral surface, including the claspers, has similar hairs. Continuous with the pale stripe down the horns runs a sub-dorsal yellowish line over the first three segments; followed by six oblique, lateral, pale yellowish lines, the first commencing on the anterior edge of the first segment and terminating on the posterior dorsal edge of the sixth segment (the others running parallel), where there is a short blue mark bordered below by whitish, followed by three lemon-yellow tubercles on each side of the pale, indistinct medio-dorsal line. The first two of each set are slightly branched; the first is longest and placed on the first of the five segmental wrinkles, which is the widest; one each on the two following wrinkles; the anal segment terminates in two points which are placed so close together as to appear united, but when the pupa has cast the larval skin they become separate. When undergoing the last two moults the larva usually selects the under surface of the leaf; both just before and after the moult its paler colour exactly resembles the colouring of the under surface of the leaves, but as soon as it has assumed the darker green hue it moves off to the upper surface, and then, selecting a certain leaf, it spins a layer of silk upon it and rests along the midrib with its head pointing to the stalk; after eating some of the leaf it feeds on the surrounding leaves, and after each hasty meal it returns to its resting-place. It feeds with great rapidity, and quickly consumes a large portion of the leaf, but leaves the midrib. It rests with the head and anterior segments curved, with the horns projecting in front and on a line with the ventral surface, the dorsal surface arched, and the anal points held slightly above the surface of the leaf; the legs are held near the body and not upon the leaf. If anything touches it it violently sweeps round the anterior half of the body from side to side as if to strike away the intruder with its horns. When about to pupate the larva spins a layer of silk down the centre of the leaf, and the stalk is carefully spun to the stem to prevent it falling off. It then rests for about two days on the silken pad with its head towards the stem, and then turns round and rests head downwards for two days more, and finally pupates. The larval state lasts about 300 days. Although the larva usually selects the under surface of the leaf for pupation, the upper side is sometimes chosen in captivity." - Frohawk (1924)

Purple Emperor - larva - Thatcham - 16-May-05 (2) [REARED]

Photo © Pete Eeles
16-May-2005

Purple Emperor - larva - Thatcham - 19-Jun-05 (4) [REARED]

Photo © Pete Eeles
19-Jun-2005

Purple Emperor - larva - Thatcham - 19-Jun-05 [REARED]

Photo © Pete Eeles
19-Jun-2005

Purple Emperor - larva - Thatcham - 20-May-04 (4) [REARED]

Photo © Pete Eeles
19-May-2004

Purple Emperor - larva - Thatcham - 20-May-04 [REARED]

Photo © Pete Eeles
19-May-2004

Purple Emperor - larva - Thatcham - 24-May-05 (5) [REARED]

Photo © Pete Eeles
24-May-2005

Purple Emperor - larva - Thatcham - 26-Jun-05 [REARED]

Photo © Pete Eeles
25-Jun-2005

Purple Emperor larva, final instar, near Arundel, 16 May 2007

Photo © Neil Hulme
16-May-2007

Purple Emperor larva, final instar, near Arundel, 25 May 2007

Photo © Neil Hulme
25-May-2007

Purple Emperor - larva - Thatcham - 03-Jun-10 (2) {REARED}

Photo © Pete Eeles
03-Jun-2010

Purple Emperor - larva - Thatcham - 03-Jun-10 (3) {REARED}

Photo © Pete Eeles
03-Jun-2010

Purple Emperor - larva - Thatcham - 03-Jun-10 (4) {REARED}

Photo © Pete Eeles
03-Jun-2010

Purple Emperor - larva - Thatcham - 03-Jun-10 (5) {REARED}

Photo © Pete Eeles
03-Jun-2010

Purple Emperor - larva - Thatcham - 03-Jun-10 (6) {REARED}

Photo © Pete Eeles
03-Jun-2010

Purple Emperor - larva - Thatcham - 04-Jun-10 (1) {REARED}

Photo © Pete Eeles
05-Jun-2010

Purple Emperor - larva - Thatcham - 20-May-11 (1) {REARED}

Photo © Pete Eeles

Purple Emperor - larva - Thatcham - 27-May-11 (1) {REARED}

Photo © Pete Eeles

Purple Emperor - larva - Thatcham - 18-Jun-13 (1) [REARED]

Photo © Pete Eeles
18-Jun-2013

Purple Emperor - larva - Thatcham - 18-Jun-13 (2) [REARED]

Photo © Pete Eeles
18-Jun-2013

Purple Emperor - larva - Thatcham - 15-May-14 [REARED]

Photo © Pete Eeles
15-May-2014

Photo Album (20 photos) ...


Pupa

The pupa is arguably the most difficult stage to find in the wild since, like the larva, it is perfectly disguised, matching the shades of green of the sallow leaf from which it is suspended upside-down, attached to the leaf by the cremaster. The pupa is a curious shape, being rather flattened so that, from the side, it looks plump whereas, from the back, it appears rather slim. This stage lasts around 2 weeks.

"The pupa, both in shape and colour, bears a remarkable resemblance to the under side of a sallow leaf. The average measurement of a male pupa is 30 mm. long, and 12.7 mm. wide across the base of the wings. Side view: Head sharply pointed; from the apex the outline gradually ascends in a curve to the abdomen, which rises high to the third segment; it then slopes backwards and curves to the anal segment, which terminates in a long cremastral process, very amply provided with brown hooks, which are firmly anchored to a pad of silk. The general dorsal outline forms an obtuse angle. The ventral surface forms a nearly straight line, being indented at the juncture of the wings and abdomen. Dorsal view: Head with two sharply pointed horns; from the point of each runs a fine keel, which unites on the posterior edge of the second abdominal segment. Between the keels is a deep furrow; a simple central keel then passes along to the anal segment. The abdomen is narrow and tapering; base of wings somewhat swollen, and much less so across the waist. The whole colouring is a pale whitish-green, exactly the colour of the under surface of a sallow leaf. There are seven oblique sub-dorsal stripes, fading away posteriorly; these are dark green above and white below. The dorsal keel is yellow on the abdomen, and blends into the white on the head points. The wings are outlined with white, and there is a sub-spiracular line continuous with the outer margin of the wing, which resembles the midrib of the leaf. The neuration is also mapped out with white. These and the oblique markings resemble the leaf veins. The entire surface is irrorated and finely granulated with numerous minute white hairs scattered over the body, except the wings." - Frohawk (1924)

Purple Emperor - pupa - Thatcham - 19-Jun-05 (2) [REARED]

Photo © Pete Eeles
19-Jun-2005

Purple Emperor - pupa - Thatcham - 19-Jun-05 (5) [REARED]

Photo © Pete Eeles
19-Jun-2005

Purple Emperor - pupa - Thatcham - 19-Jun-05 (7) [REARED]

Photo © Pete Eeles
19-Jun-2005

Purple Emperor - pupa - Thatcham - 28-Jun-05 (2) [REARED]

Photo © Pete Eeles
03-Jul-2005

Purple Emperor pupa, near Arundel, 5 July 2007

Photo © Neil Hulme
05-Jul-2007

Purple Emperor - pupa - Thatcham - 01-Jun-11 (1) {REARED}

Photo © Pete Eeles

Purple Emperor - pupa - Thatcham - 27-May-11 (1) {REARED}

Photo © Pete Eeles

Purple Emperor - pupa - Thatcham - 27-May-11 (2) {REARED}

Photo © Pete Eeles

Purple Emperor - pupa - Thatcham - 07-Jun-14 [REARED]

Photo © Pete Eeles
07-Jun-2014

Purple Emperor - pupa - Thatcham - 13-Jun-14 [REARED]-2

Photo © Pete Eeles
13-Jun-2014

Purple Emperor - pupa - Thatcham - 13-Jun-14 [REARED]

Photo © Pete Eeles
13-Jun-2014

Purple Emperor pupa - Knepp Estate, Sussex 21-June-2016

Photo © Neil Hulme
21-Jun-2016

Purple Emperor pupa - Knepp Estate 3-July-2016

Photo © Neil Hulme
03-Jul-2016

Purple Emperor pupa (female) - Knepp Estate, Sussex 14-July-2016

Photo © Neil Hulme
14-Jul-2016

Photo Album (14 photos) ...


Aberrations

Description to be completed.

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Similar Species

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The following links provide additional information on this butterfly.

References

The species description provided here references the following publications:

ReferenceDetails
Boisduval (1840) Boisduval, J.A. (1840) Genera et index methodicus Europaeorum lepidopterum.
Fabricius (1807) Fabricius, J.C. (1807) Magazin für Insektenkunde, herausgegeben von Karl Illiger.
Frohawk (1924) Frohawk, F.W. (1924) The Natural History of British Butterflies.
Lewin (1795) Lewin, W. (1795) The Papilios of Great Britain.
Linnaeus (1758) Linnaeus, C. (1758) Systema Naturae. Edition 10.
Morris (1853) Morris, Rev.F.O. (1853) A History of British Butterflies.
Petiver (1702-1706) Petiver, J. (1702-1706) Gazophylacii naturae et artis decas prima.
Rafinesque (1815) Rafinesque, C.S. (1815) Analyse de la nature ou Tableau de l'univers et des corps organisés.
Rennie (1832) Rennie, J. (1832) A conspectus of the butterflies and moths found in Britain, with their English and systematic names, times of appearances, sizes, colours, their caterpillars, and various localities.
Wilkes (1742) Wilkes, B. (1742) Twelve New Designs of English Butterflies.
Wilkes (1749) Wilkes, B. (1749) The English moths and butterflies: together with the plants, flowers and fruits whereon they feed, and are usually found.