| Family | Lycaenidae |
|---|---|
| Subfamily | Polyommatinae |
| Genus | Agriades |
| Species | optilete |
| Authority | (Knoch, 1781) |
| English Name | Cranberry Blue |
| European Red List 2010 | Least Concern (LC) |
|---|---|
| EU 27 Red List 2010 | Least Concern (LC) |
| European Red List 2025 | Vulnerable (VU) |
| EU 27 Red List 2025 | Vulnerable (VU) |
| Habitats Directive | |
| Bern Convention | |
| CITES |
The Cranberry Blue occurs on raised bogs, heath and also in woodland clearings, where dwarf shrubs are growing. Although populations are at times extremely small, they can also have considerable numbers of butterflies. Eggs are laid on Marsh Andromeda (Andromeda palustris), Erica tetralix, Empetrum nigrum, and a small number of Vaccinium species, including Cranberry (V. oxycoccus). The caterpillars eat both the flowers and leaves of the foodplants, moving from one plant to another. When they are half-grown, they move into the litter layer and hibernate. However, they pupate on the plant, spinning a silken girdle in which the pupa hangs. The Cranberry Blue has one generation a year.
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