Large blue butterfly  (Maculinea arion)

Widely distributed throughout Europe except for the extreme north and southern parts of Spain. The large blue became extinct in the UK in 1979.

This butterfly likes south-facing hillsides with close-cropped, unfertilised pasture. It requires the caterpillar's food plant, wild thyme, in the presence of a species of ant, Myrmirca sabuleti.