Andy Sands / Holly Blue butterfly (Celastrina argiollus) On ivy leaf (Hedera sp) with wings open, Hertfordshire, England, UK, May

Bernard Castelein / Holly Blue Butterfly (Celastrina argiolus). Belgium, April.

Mark Payne-Gill / Holly Blue Butterfly (Celastrina argiolus) larva on Ivy flower head (Hedera helix). Studio, Bristol.

Bernard Castelein / Holly blue butterfly (Celastrina argiolus), Brasschaat, Belgium, July

Robert Thompson / Holly blue butterfly (Celastrina argiolus) Rostrevor Oakwood NNR, County Down, Northern Ireland, UK, May

Stephen Dalton / Holly blue butterfly (Celastrina argiolus) feeding on Holly leaf. UK, Europe

Andy Sands / Holly Blue butterfly (Celastrina argiolus) wings closed, feeding on Purple Loosestrife, West Sussex, England, UK

Andy Sands / Holly Blue butterfly {Celastrina argiollus} on Holly leaf, Hertfordshire, UK.

Andy Sands / Holly Blue butterfly {Celastrina argiollus} profile on Holly leaf, Hertfordshire, UK.

Andy Sands / Holly blue butterfly {Celastrina argiolus} resting on Holly flowers, Captive, UK.

Chris Shields / Illustration of Holly blue butterfly (Celastrina argiolus), Lycaenidae.

Robert Thompson / Holly blue butterfly (Celastrina argiolus) on bluebell flowers, Rostrevor Oakwood NNR, County Down, Northern Ireland, UK, May

Paul Hobson / Holly blue butterfly {Celastrina argiolus} on new ivy. UK