First documented record of a reproducing population of Papilio alexanor Esper, 1800 (Lepidoptera, Papilionidae) in Southern Italy, with ecological notes

Papilio alexanor Esper, 1800 is a strictly protected butterfly in Europe, where its previously known range is restricted to south-eastern France, north-western Italy, and parts of the Balkan Peninsula. In Italy, stable reproducing populations had been detected exclusively within Liguria and Piedmont. Regarding southern Italy, only scattered historical records had been documented, leading researchers to speculate that no established populations had existed in this region. Below is the first documented evidence of stable reproducing populations of P. alexanor in southern Italy, discovered along the border between Campania and Basilicata. Field surveys were conducted during April-May 2025 and April-May 2026. A reproducing population was confirmed, concentrated at two main sites covering an area of approximately 1 km 2 . Ferula glauca L. is documented here for the first time as a larval host plant of P. alexanor in Italy; prior to this record, the host plants documented belonged to other ecologically and morphologically distinct Apiaceae genera. Use of Ferula species had previously been reported for Balkan and Asian populations. The early flight phenology (early April to the end of May) is markedly earlier than in northern Italian and French populations. We suggest that this phenological mismatch, combined with the difficult access to the cliff habitats, may partly explain the absence of previous records, though the origin of these remains to be determined. The biogeographic and conservation implications of these findings are being discussed, including the need to revise the species’ conservation status under the European Habitats Directive and the IUCN Red Lists.