Herein we present the results of the first mark-release-recapture (MRR) study on five populations of Phengaris alcon near Lamas D´Ôlo, a small village located in the Natural Park of Alvão (PNA) in Portugal. For the study of the adult demographic parameters, a MRR study was conducted during the flight period on the five meadow sites, named: Li: Libania; PM: Plana dos Mijaceiros; PR: Ponte Romana; FM: Frente do M...