INTRODUCTION The Stelvio National Park, extended over 130.700 ha, is the largest protected area within the Ital- ian Alps. Its territory, extended among Lombardy (provinces of Sondrio, SO, and Brescia, BS), Trentino (province of Trento, TN) and South Tyrol (province of Bolzano, BZ), is mainly alpine and located for about three quarters above 2000 metres, with maximum alti- tude at mount Ortles (3905 meters a.s.l.). Between 2013 and 2015 the Park promoted an extensive monitoring activity on many animal taxa within the “Animal biodiversity monitoring in the alpine environment” project. The project has been co- ordinated by Gran Paradiso National Park and imple- mented in the four Alpine National Parks, together with Val Grande and Dolomiti Bellunesi National Parks. As the current loss of biodiversity requires long-term mon- itoring studies of the distribution of living organisms, particularly in regions, such as mountains, which are highly sensitive to climatic and environmental changes, the same monitoring effort will be repeated every five years to highlight the response of alpine biodiversity to climate and land-use changes. The aim of the project is to assess the distribution of different taxa along altitu- dinal gradients and the relative influence of geograph- ical, environmental and climatic factors. This paper lists the species of butterflies found during field research carried out in the study period, in addition to species known only from literature data, with the aim to update the knowledge about these im- portant environmental quality indicators (Fleishman & Murphy, 2009; van Swaay et al., 2010; Balletto et al., 2015). MATERIALS AND METHODS Within the Park boundaries standardized sam- plings have been carried out between 2013 and 2015. The choice of sampling plots (77 in total) has been made by Park Authority on the basis of habitats and altitudes. Butterfly data have been recorded in 65 plots (Tab. 1 and Fig. 1), of which 27 in South Tyrol (sur- veyed in 2014-2015), 13 in Trentino (2014-2015) and MEMORIE SOC. ENTOMOL. ITAL., 94 (1-2): 57-89, ISSN 0037-8747 15 DICEMBRE 2017 Riassunto: I Lepidotteri Ropaloceri (Lepidoptera Hesperioidea, Papilionoidea) del Parco Nazionale dello Stelvio. Vengono esposti i risultati delle ricerche faunistiche sui Lepidotteri Ropaloceri del Parco Nazionale dello Stelvio, condotte tra il 2013 e il 2015 nell’ambito del progetto “Monitoraggio della biodiversità animale in ambiente alpino”. Nell’area sono state censite 144 specie, pari al 49,66% della ropalocerofauna italiana, di cui varie d’interesse conservazionistico e biogeografico. Abstract: This paper presents the results of a research on the butterflies of Stelvio National Park, carried out by the authors between 2013 and 2015 within the “Animal biodiversity monitoring in the Alpine environment” project. In the study area 144 species are represented, corresponding to 49,66% of the Italian butterfly fauna, many of which are of conservational and biogeographical importance. Key words: Butterflies, Rhopalocera, Italy, Stelvio National Park, Alps, biodiversity, distribution, conservation. 57 Marco BONIFACINO * - Luca CRISTIANO ** - Roberta ROSSI *** - Daniele BARONI **** - Luca PEDROTTI ***** - Roberto SINDACO ** The butterflies of the Stelvio National Park (Lepidoptera Hesperioidea, Papilionoidea) * Marco Bonifacino, Via Caviglia 8, 17047 Vado Ligure (SV), Italy. E-mail: mbonifacino2317@gmail.com ** Luca Cristiano, Roberto Sindaco, c/o Museo Civico di Storia Naturale, Via San Francesco di Sales 88, 10022 Carmagnola (TO), Italy. E-mail: luca.museo@gmail.com; rsindaco@gmail.com *** Roberta Rossi, Via Fatebenefratelli 4, 10137 Torino (TO), Italy. E-mail: robertarossipg@gmail.com **** Daniele Baroni, Via Gaspare Buffa 4, 16158 Genova (GE), Italy. E-mail: dbaroni12@gmail.com ***** Luca Pedrotti, Ersaf – Direzione Parco Nazionale dello Stelvio, Via De Simoni 42, 23032 Bormio (SO), Italy. E-mail: luca.pedrotti@stelviopark.it Non-commercial use only