Corsican swallowtail (Papilio hospiton)
The Corsican swallowtail butterfly Papilio hospiton is endemic to the islands of Sardinia and Corsica where it is widespread and generally low in density but with some areas of higher local density. It is included in the list of endangered species issued by the Washington Convention (CITES, 1973). The butterfly has an open population structure and occurs in a variety of open landscapes where males display typical hilltopping behaviour. At least three foodplants sustain populations, from sea level to high elevation, Peucedanum paniculatum, Ferula communis and Ruta corsica; all are toxic to grazing mammals and are sustained by traditional land use, characterized by overgrazing and controlled burning. These plants have significantly different effects on the growth rate of Papilio hospiton, and their distribution seems strongly to influence the butterflies' density. The Parc Régional Naturel de la Haute Corse provides ecological supervision which is, on the whole, favourable to the survival of P. hospiton. At present, there is no evidence that Papilio hospiton is experiencing a decline of its populations and hence it cannot be classified as an endangered species, as defined by the IUCN. It is however vulnerable, because it has a restricted range and is very sensitive to land use changes. Elimination of its host plants, typically considered weedy, could almost completely eradicate its populations within a very short time. There is an obvious conflict between economic development and conservation of biodiversity in Corsica as elsewhere.