Biogeographia vol. )OO( - 2011 (Pubblicato il 23 dicembre 2011) La Biogeografia de//a Sicilia Diversity and biogeographical remarks on “Symphyta” of Sicily (Hymenoptera) GIUSEPPE FABRIZIO TURRISI University of Ccztnnirz, C U TGANA, Section of Nature Reserve: Management, via Yerzorzz 8, 95027 San Gregorio di Crztnnin, Cntnnin (lzfizly); e—mni[: turrisifn/7rizio @yaboo. it Key words: Hymenoptera, “Symphyta”, Sicily, Mediterranean basin, diversity, zoogeography. SUMMARY The present contribution deals with a zoogeographic analysis of the sawfly-fauna of Sicily in a wider Mediter- ranean insular context. The sawfly-fauna of Sicily currently includes 119 species (6 of which doubtfully present) comprised within nine families (number of species in brackets): Xyelidae (2), Xiphydriidae (1), Siricidae (2), Orus- sidae (4), Cephidae (12), Argidae (10), Cimbicidae (5), Diprionidae (2) and Tenthredinidae (75). The analysis of chorotypes shows a higher percentage of species having a wide distribution (49% in total, specifically: Holoarctic 8%; Palaearctic 4%; \X7est—palaearctic 5%; Eurasian 32%). A high percentage of species has an European distribu- tion (44%, of which 7% extended to Maghreb). Very low is the percentage ofWest-mediterranean species (2%) and the endemic one of Italy (only 1%), whereas the Sicilian endemic species is more conspicuous (4%). The com- parison of the sawfly-fauna of Sicily with other insular contexts of Mediterranean basin, based on a linear regres- sion of species number vs. insular area and multivariate analyses (cluster analysis and neighbour—joining), shows that it is the most diversified and rich-species. INTRODUCTION The “Symphyta” include more than 8300 described species (Taeger and Blank, 2008; Taeger et al., 2010) within 15 families, mostly belonging to Ten- thredinidae. The “Symphyta”, also called sawflies, are traditionally considered as suborder of Hymenoptera mainly on the basis of a unique morphological feature, namely the configuration of the abdomen without the so called “Wasp waist”, which reperesents an autapomorphy of the Apocrita. Thus, the unique commonly shared morphological character is clearly a plesiomorphism and sawflies are currently considered as a paraphiletic assemblage (a grade) and not a true clade (see Vilhelmsen, 2006). The “Symphyta” are mostly phytophagous during the larval stages, includ- ing a strict mycetophagy and Xylophagy, while imagos are pollinophagous and nectariphagous, although a few Tenthredinidae are also predators. However, among the wide assemblage of Symphyta the small family Orussidae includes