Cupido alcetas (Hoffmannsegg, 1804) (Lepidoptera, Lycaenidae), espèce nouvelle pour la faune d’Alsace (France, Grand Est)

Abstract  - Cupido alcetas (Hoffmannsegg, 1804) is a Mediterranean-Asian lepidoptera present in France, where it was historically confined to the southernmost regions. Probably favoured by climate changes, it has been colonising higher latitudes since the 1970s. It has been present on the borders of Alsace for several years, in the Swiss Jura and the Basel region, and its arrival in the region was expected. After a very favourable year for the species in 2022, its presence has been certified for the first time in Alsace, where several specimens were observed in August 2022 in the National Nature Reserve of the Petite Camargue Alsacienne. The following year, the species was also recorded at the same station with the observation of dozens of individuals, including females laying eggs on Medicago lupulina L., 1753 and Vicia cracca L., 1753.