Robert Thompson / Large blue butterfly (Phengaris arion) nectaring on Yarrow (Achillea millefolium). St Caterina di Valfurva Valfurva, Sondrio, Lombardy, Italy.

MYN / Lily Kumpe / Blue butterfly (Glaucopsyche lycormas) Dugana Khad, Tuv Province, Mongolia. Meetyourneighbours.net project.

Jussi Murtosaari / Large blue butterfly (Maculinea arion), female, Finland, July.

Jussi Murtosaari / Large blue (Maculinea arion), female at habitat, Finland, July.

Jussi Murtosaari / Large blue butterfly (Maculinea arion), feeding from Creeping Thyme (Thymus serpyllum), Finland, July.

Lorraine Bennery / Green-underside blue butterfly (Glaucopsyche alexis) and Wood white butterfly (Leptidea sinapis) puddling, Grands Causses Regional Natural Park, France, May.

Lorraine Bennery / Green-underside blue butterfly (Glaucopsyche alexis) on grass, Grands Causses Regional Natural Park, France, May.

Lorraine Bennery / Green-underside blue butterflies (Glaucopsyche alexis) pair mating, Herault, France, May.

Lorraine Bennery / Large blue butterfly (Maculinea arion) on flower, Indre-et-Loire, France

Edwin Giesbers / Green-underside blue butterfly (Glaucopsyche alexis) resting on Campanula Bloemenblauwtje; Aosta Valley, Gran Paradiso National Park, Italy.

MYN / Dirk Funhoff / Green-underside blue butterfly (Glaucopsyche alexis) pupa, Lorsch, Hessen, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Green-underside blue butterfly (Glaucopsyche alexis), Lorsch, Hessen, Germany. May. Meetyourneighbours.net project

Jussi Murtosaari / Blue butterfly (Glaucopsyche) in flight, Liperi, Finland, July.

Jussi Murtosaari / Blue butterfly (Glaucopsyche) laying eggs, Liperi, Finland, July.

Robert Thompson / Green Underside Blue butterfly (Glaucopsyche alexis) Mercantour National Park, Provence, France, June.

Jussi Murtosaari / Large blue butterfly (Maculinea arion) Liperi, Pohjois-Karjala / North Karelia, Ita-Suomi / Eastern Finland, Finland. June

MYN / Dirk Funhoff / Dusky Large Blue (Maculinea nausithous), Erpolzheim, Rhineland-Palatinate, Germany, August. meetyourneighbours.net project

MYN / Dirk Funhoff / Dusky Large Blue (Maculinea nausithous), Erpolzheim, Rhineland-Palatinate, Germany, August. meetyourneighbours.net project

Robert Thompson / Large blue butterfly (Phengaris arion) on flower head, Viscos, Pyrenees National Park, Hautes Pyrenees, France, July

Jussi Murtosaari / Large Blue butterfly (Phengaris arion) male feeding on nectar, eastern Finland, June.

Jussi Murtosaari / Large Blue butterfly (Phengaris arion) female laying eggs, eastern Finland, June.

Jussi Murtosaari / Large Blue butterfly ( Phengaris arion) feeding, eastern Finland, June.

Jussi Murtosaari / Green-Underside Blue butterfly (Glaucopsyche alexis) male, central Finland, June.

Jussi Murtosaari / Green-Underside Blue butterfly (Glaucopsyche alexis) female, South Karelia, southern Finland, June.

Jussi Murtosaari / Green-Underside Blue butterfly (Glaucopsyche alexis) male, central Finland, June.

Jussi Murtosaari / Green-Underside Blue butterfly (Glaucopsyche alexis) male, central Finland, June.

Paul Harcourt Davies / Green-underside blue butterfly (Glaucopsyche alexis) portrait, Sibillini, Umbria, Italy. May.

Michel Poinsignon / Green-underside blue butterfly (Glaucopsyche alexis) resting on Early purple orchid (Orchis mascula), Lorraine, France. May.

Paul Harcourt Davies / Green-underside blue butterfly (Glaucopsyche alexis) resting on blue flower, Umbria, Italy. May.

Jussi Murtosaari / Large blue (Maculinea arion) butterfly nectaring on Thyme (Thymus sp). Liperi, North Karelia, Finland. July.