Alex Hyde / Purple emperor butterfly (Apatura iris) male on English Oak (Quercus robur) leaf basking with wings open, UK, Captive.

Hans Christoph Kappel / Lesser Purple Emperor butterfly caterpillar

Hans Christoph Kappel / Lesser Purple Emperor butterfly.

David Woodfall / Purple emperor butterfly (Apatura iris) male basking on ground. Knepp Rewildling Estate, Sussex, England, UK.

David Woodfall / Purple emperor butterfly (Apatura iris) male on field maple hedge. Knepp Rewildling Estate, Sussex, England, UK.

David Woodfall / Purple emperor butterfly (Apatura iris) female with closed wings. Knepp Rewildling Estate, West Sussex, England, UK.

David Woodfall / Tamworth pig with mud on its snout from rooting around in soil which helps to create a habitat for Purple emperor butterflies (Apatura iris), Knepp, West Sussex, UK. June. Small repro only.

David Woodfall / Purple emperor butterfly (Apatura iris) male puddling. Knepp Wildland Project, formerly intensive farmland now turned to conservation and sustainable farming. Horsham, West Sussex. England, UK. June

David Woodfall / Purple emperor butterfly (Apatura iris) female on rose bush. Knepp Wildland Project, formerly intensive farmland now turned to conservation and sustainable farming. Horsham, West Sussex. England, UK....

David Woodfall / Purple emperor butterfly (Apatura iris) female on rose bush. Knepp Wildland Project, formerly intensive farmland now turned to conservation and sustainable farming. Horsham, West Sussex. England, UK....

David Woodfall / Purple emperor butterfly (Apatura iris) male puddling. Knepp Wildland Project, formerly intensive farmland now turned to conservation and sustainable farming. Horsham, West Sussex. England, UK. June

David Woodfall / Purple emperor butterfly (Apatura iris) male on Goat willow (Salix caprea). Knepp Wildland Project, formerly intensive farmland now turned to conservation and sustainable farming. Horsham, West Sussex...

David Woodfall / Purple emperor butterfly (Apatura iris ) male on Oak leaf. Knepp Wildland Project, formerly intensive farmland now turned to conservation and sustainable farming. Horsham, West Sussex. England, UK. Ju...

Kim Taylor / Purple emperor butterfly (Apatura iris) male on birch showing coiled proboscis. Surrey, England, UK, June.

MYN / Dirk Funhoff / Purple emperor butterfly (Apatura iris) showing irridescence on one wing due to angle of view, Mannheim, Germany. June.

Jussi Murtosaari / Purple emperor butterfly (Apatura iris), female on the ground, Finland

Jussi Murtosaari / Purple emperor butterfly (Apatura iris), male on a leaf, Finland, August.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia), sitting on a leaf, Finland, August.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia), male, Finland, August.

Lorraine Bennery / Purple emperor butterfly (Apatura iris) male puddling, Haute-Marne, France, June.

MYN / Dirk Funhoff / Purple emperor butterfly (Apatura iris) pupa, Mannheim, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Purple emperor butterfly (Apatura iris) pupa, Mannheim, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Purple emperor butterfly (Apatura iris) adult showing underwing, Mannheim, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Purple emperor butterfly (Apatura iris) adult, Mannheim, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia), Mannheim, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia), Mannheim, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia), Mannheim, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Purple emperor butterfly (Apatura iris) caterpillar with silk, Lorsch, Hessen, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia), Lorsch, Hessen, Germany. May. Meetyourneighbours.net project

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia) caterpillar, Lorsch, Hessen, Germany. May. Meetyourneighbours.net project

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia), Lorsch, Hessen, Germany. July. Meetyourneighbours.net project

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia) pupa on leaf, Lorsch, Hessen, Germany. Meetyourneighbours.net project

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia) pupa, Lorsch, Hessen, Germany. Meetyourneighbours.net project

MYN / Dirk Funhoff / Purple emperor butterfly (Apatura iris) caterpillar, Lorsch, Hessen, Germany. May. Meetyourneighbours.net project

MYN / Dirk Funhoff / Lesser purple emperor butterfly (Apatura ilia), Lorsch, Hessen, Germany. June. Meetyourneighbours.net project

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia), female, South Karelia, Finland, August.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia) male on the ground, South Karelia, Finland, August.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia), male sitting on a stone with a fly, South Karelia, Finland, August.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia), male sitting on a leaf, South Karelia, Finland, August.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia), male sitting on a leaf, South Karelia, Finland, August.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia) female on a leaf of aspen, Finland. July

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia) butterfly, Finland. July

Jussi Murtosaari / Purple Emperor butterfly (Apatura iris) female on ground, South Karelia, southern Finland, July.

Jussi Murtosaari / Lesser Purple Emperor butterfly (Apatura ilia) male in oak tree, Finland, July.

Jussi Murtosaari / Purple Emperor butterfly (Apatura iris) male puddling on ground, South Karelia, southern Finland, July.

Jussi Murtosaari / Lesser Purple Emperor butterfly (Apatura ilia) female on grass flowers, southern Finland, August.

Jussi Murtosaari / Purple Emperor butterfly (Apatura iris) male puddling, South Karelia, southern Finland, July.

Jussi Murtosaari / Lesser Purple Emperor butterfly (Apatura ilia) male in oak tree, Finland, July.

Thomas Marent / Purple Emperor (Apatura iris) caterpillar, Switzerland

Jussi Murtosaari / Lesser Purple Emperor (Apatura ilia) male drinking moisture from lichen covered branch, Finland, July

Alex Hyde / Purple Emperor Butterfly (Apatura iris) male on English Oak (Quercus robur) leaf basking with wings open. Captive, UK

Alex Hyde / Purple Emperor Butterfly (Apatura iris) male with wings open, against white background. Captive, UK.

Alex Hyde / Purple Emperor Butterfly (Apatura iris) male resting with wings closed against white background. Captive, UK.

Alex Hyde / Purple Emperor Butterfly (Apatura iris) male against white background. Captive, UK.

Alex Hyde / Purple Emperor Butterfly (Apatura iris) male on English Oak (Quercus robur) leaf with wings closed. Captive, UK

Alex Hyde / Purple Emperor Butterfly (Apatura iris) male, close up of wing showing iridescent purple scales. Captive, UK.

Alex Hyde / Chrysalis of Purple Emperor Butterfly (Apatura iris), camouflaged using leaf mimicry. Captive, UK.

Alex Hyde / Caterpillar of Purple Emperor Butterfly (Apatura iris) camouflaged, leaf mimicry. Captive, UK.

Alex Hyde / Caterpillar of Purple Emperor Butterfly (Apatura iris), camouflaged against the vein of leaf. Captive, UK.

Mark Payne-Gill / Purple Emperor Butterfly (Apatura iris) larva showing defensive camouflage effect on Sallow leaf (Salix caprea). Studio, Tetbury.

Mark Payne-Gill / Hibernating Purple Emporer Butterfly (Apatura iris) larva with snow melting on Sallow branch (Salix caprea). Studio, Tetbury.

Mark Payne-Gill / Hibernating Purple Emporer Butterfly (Apatura iris) larva with snow melting on Sallow branch (Salix caprea). Studio, Tetbury.

Mark Payne-Gill / Purple Emperor Butterfly (Apatura iris) resting on Sallow leaf (Salix caprea). Alice Holt Forest, Surrey, July.

Dave Watts / Purple Emperor Butterfly (Apatura iris) at rest on Oak tree (Quercus) branch, France

Dave Watts / Purple Emperor Butterfly (Apatura iris) at rest on Oak tree (Quercus) branch, France

Stephen Dalton / Caterpillar larva of Lesser purple emperor (Apatura ilia) camouflaged on green leaf, Europe

Robin Chittenden / Purple emperor (Apatura iris) sunning on stone with wings spread out, Hautes-Pyrenees, France. June

Dietmar Nill / Purple emperor butterlfy (Apatura iris) Germany

Andy Sands / Purple Emperor (Apatura iris) on Oak leaves basking with wings open, Captive, UK

Andy Sands / Purple Emperor butterfly (Apatura iris) on Oak with wings closed, Captive, UK

Andy Sands / Purple Emperor butterfly (Apatura iris) on Oak leaf basking with wings open, Captive, UK

Thomas Marent / Lesser Purple Emperor (Apatura ilia) butterfly, Switzerland

Thomas Marent / Purple Emperor (Apatura iris) butterfly, Switzerland

Hans Christoph Kappel / Lesser purple emperor butterfly {Apatura ilia clytie} wings open, Germany

Hans Christoph Kappel / Lesser purple emperor butterfly {Apatura ilia clytie} wings closed, Germany

Adrian Davies / Purple emperor butterfly male (Apatura iris) UK

Adrian Davies / Purple emperor butterfly male {Apatura iris} UK

Paul Hobson / Male Purple emperor butterfly {Apatura iris} wings closed, feeding on horse dung, southern England, UK.

Paul Hobson / Purple emperor butterfly {Apatura iris} male with wings open on Oak (Quercus sp) leaves, southern England, UK.

Paul Hobson / Purple emperor butterfly {Apatura iris} male with wings open on Oak (Quercus sp) leaves, southern England, UK.

Hans Christoph Kappel / Lesser Purple Emperor caterpillar about to pupate

Chris Shields / Illustration of Purple emperor butterfly (Apatura iris).

Robert Thompson / Purple emperor butterfly (Apatura iris) resting with wings closed on Oak leaf, Southern France, July

Robert Thompson / Purple emperor butterfly (Apatura iris) recently emerged from chrysalis, Southern France

Robert Thompson / Purple emperor butterfly (Apatura iris) resting on dung with wings closed, Southern France

Robert Thompson / Purple emperor butterfly (Apatura iris) Southern France

Robert Thompson / Lesser purple emperor butterfly (Apatura ilia) camouflaged on ground with wings closed, near Couiza, France, July

Robert Thompson / Lesser purple emperor butterfly (Apatura ilia) wings open, near Couiza, France, July

Robin Chittenden / Male Purple emperor (Apatura iris) on ground, Pyrenees, France, July

Robin Chittenden / Purple emperor butterfly (Apatura iris) on ground, Hautes-Pyrenees, France, July

Robin Chittenden / Purple emperor butterfly (Apatura iris) on ground, Hautes-Pyrenees, France, July

Robin Chittenden / Purple emperor butterfly (Apatura iris) feeding on faeces, Hautes-Pyrenees, France, July

Robin Chittenden / Male Lesser purple emperor butterfly (Apatura iris) on twig, Zemplen Hills, Hungary, July

Robin Chittenden / Lesser purple emperor butterfly (Apatura ilia) n ground, Austria, September

Robin Chittenden / Purple emperor (Apatura iris) Hautes-Pyrenees, France, July

Robin Chittenden / Male Purple emperor butterfly (Apatura iris) on ground, Pyrenees, France, July