Jussi Murtosaari / Cranberry blue butterfly (Plebeius optilete), male, Finland, July.

Jussi Murtosaari / Cranberry blue butterfly (Plebeius optilete), male, Finland, July.

Jussi Murtosaari / Common blue butterfly (Plebeius icarus), female, Finland, July.

Will Watson / Wild Cranberry (Vaccinium oxycoccos), fruit and flowers and Bilberry (Vaccinium myrtillus), growing on the Stiperstones National Nature Reserve, Shropshire, England, UK, September,

Jussi Murtosaari / Cranberry blue butterfly (Plebejus optilete) Kitee, Pohjois-Karjala / North Karelia, Finland, July.

Jussi Murtosaari / Cranberry blue butterfly (Plebejus optilete) Lieksa, Pohjois-Karjala / North Karelia, Finland

Alex Hyde / Cranberry blue (Plebejus optilete) 'mud-puddling' to extract scarce minerals such as sodium. Nordtirol, Austrian Alps, July.

Jussi Murtosaari / Cranberry Blue butterfly (Plebejus optilete) male, South Karelia, southern Finland, June.

Silvia Reiche / Cranberry Blue (Vacciniina optilete) butterfly, Hohe Tauern National Park, Austria

Silvia Reiche / Cranberry Blue (Vacciniina optilete) butterfly on orchid, Hohe Tauern National Park, Austria

Silvia Reiche / Cranberry Blue (Vacciniina optilete) butterfly on orchid, Hohe Tauern National Park, Austria

Silvia Reiche / Cranberry Blue (Vacciniina optilete) butterfly on orchid, Hohe Tauern National Park, Austria

Silvia Reiche / Cranberry Blue (Vacciniina optilete) butterfly on Cross-leaved Heath (Erica tetralix) flowers, Drenthe, Netherlands

Silvia Reiche / Cranberry Blue (Vacciniina optilete) butterfly on Cross-leaved Heath (Erica tetralix) flowers, Drenthe, Netherlands

Silvia Reiche / Cranberry Blue (Vacciniina optilete) butterfly on Heather (Calluna vulgaris), Drenthe, Netherlands

David Welling / Yukon Blue Butterfly on leaf (Plebejus optilete), Alaska, USA

Erlend Haarberg / Cranberry blue (Agriades optilete) puddling, Jotunheimen National Park, Norway, June.