Maculinea arion (Linné, 1758) nel Parco Fluviale Gesso Stura (CN)

ABSTRACT - Maculinea arion (Linné, 1758) in the «Parco Fluviale Gesso Stura» (Cuneo, NW Italy). This study was based on a population of Maculinea arion ligurica occurring within the “Parco Fluviale Gesso e Stura di Cuneo”, in Piedmont (NW Italy). We monitored this population in the years 2007-2008, by Mark Release-Recapture method. The estimated population size fluctuated between 162 (2007) and 255 (2008) individuals. Densities varied between 0.15 and 0.30 sp/ha, during the same period. The operational sex ratio was of 1.03 and 0.94, respectively. Demographic parameters indicate that the population is relatively small, but apparently stable. As concerns the potential host ants, we have identified 4 Myrmica species existing in cohabitation with M. arion. All have been cited as host species in the regards literature and all can potentially host the larvae and pupae of this butterfly. No direct observation of larvae are available, however, at the moment, within any of the excavated nests. To come to the initial larval food-plant, which in this case is Origanum vulgare, we observed that it has a patchy distribution, and that it is seldom co-present with Myrmica ants nests. The studied population requires that effective management and conservation measures are urgently implemented, also taking in consideration the considerable anthropic transformation currently under way in the broader area.