The larvae feed on Fabaceae as especially Medicago and Onobrychis. In addition, the species also often oviposits at broom, such as Spartium junceum in Provence (still closed flower buds). I found larvae there also, along with those of Glaucopsyche melanops, on Dorycnium pentaphyllum.
Glaucopsyche alexis inhabits nutrient-poor grasslands and pastures, open scrub, wide margins and verges and similar places that are usually warm and sometimes show some air humidity.
The pupa hibernates. Adults fly from April to June. The caterpillars are found from late May to July. Eggs are laid onto the still closed flower buds as I could watch several times in Provence in May 2006.
Endangerment: strongly endangered
North of the Alps, Glaucopsyche alexis is highly threatened due to habitat loss (agriculture, frequent mowing of verges and other areas, eutrophication, overbuilding). It still occurs only very locally, e.g. in the Kaiserstuhl area in southwest Germany.
Glaucopsyche alexis ccurs from North Africa across Europe to the Asian Amur region. In Europe it misses in Northern Scandinavia, on the British Isles, in the northwestern part of Central Europe and locally in some southernmost regions (e.g. Southern Greece).