The Butterfly Week 2018 focused on the study of Parnassius mnemosyne in the Parco delle Foreste Casentinesi, from 23 to 30 June. During the week we evaluated the consistency of the populations and the movements between the various clearings of this species through Capture Marking Recapturing (CMR). The characteristics of the host plants had also been evaluated so as to be able to intervene in the future to restore and maintain its habitat. It is a protected species and, along with many others, at risk due to climate change. It is precisely following the rise in temperatures that populations are always moving to higher altitudes where we find ridge clearings that are increasingly reduced due to the expansion of forests.