Notes on the ant biodiversity, ecology and biogeography (Hymenoptera: Formicidae) of Astypalaia Island (SE Aegean)

Situated in the Aegean archipelago, Astypalaia is one of the most isolated islands, forming a transitional zone between the Cyclades and the Dodecanese island groups. Despite studies on its biodiversity for a number of taxa, up-to-date species inventories of ants include a checklist of just 11 species, collected only from the surrounding small islets Agia Kyriaki, Kounoupoi, and Ofidoussa. During a 10-day investigation (14–24 April 2024), the island of Astypalaia was visited. This article provides the first checklist of the island’s ant biodiversity, reporting 30 species and morpho-species. Notes, which also report on five alien species, discuss the taxonomic status, distribution, and ecology of the island’s myrmecofauna. Investigations on faunal dissimilarities between the eastern and western parts of the island indicated no partitioning. Our analyses showed a greater affinity of Astypalaia’s myrmecofauna with that of other Cycladic islands, rather than the myrmecofauna of the Dodecanese islands, which supports some previous investigations regarding other taxonomic groups of both vertebrates and invertebrates. Nevertheless, our records of the Aegean ants are far from complete, necessitating further research on the biodiversity and biogeography of ants in the Aegean archipelago.