(Prunner, 1798)
Glandon Blue
Description:
In Scandinavia, the Glandon Blue occurs on slate and shale rocks with patches of grassy vegetation and Crowberry (Empetrum nigrum), especially in areas sheltered from the northwestern wind. In Central Europe, they are found up to the snow-line on grassy vegetation, where the food plants grow on open patches, such as on scree slopes and beside streams. On calcareous soils, Androsace chamaejasme is used, and on non-calcareous soils, the caterpillars feed on A. obtusifolia and Vitaliana primuliflora. In the Sierra Nevada, these butterflies are found in sheltered depressions in an otherwise open landscape, where the food plant Vitaliana primuliflora grows abundantly.
The food plants here are probably Yellow Mountain Saxifrage (Saxifraga aizoides), Purple Saxifrage (Saxifraga oppositifolia), and possibly Alpine Milk-vetch (Astragalus alpinus). The caterpillars feed on the leaves and sometimes the flowers of the food plants.
The Glandon Blue hibernates as a caterpillar, and in all parts of its range has one generation a year.
Habitat:
Alpine grasslands
Screes
Similar species:
Plebeius pyrenaica
Plebeius orbitulus
Aricia nicias