Recent confirmation of a single haplotype in the Italian population of Vespa velutina

Abstract

Vespa velutina Lepeletier, 1836 (Hymenoptera: Vespidae), the yellow-legged hornet, is a social wasp native to North of India, China and tropical and subtropical areas of Southeast Asia. Adults are predators of a wide variety of arthropods, including honey bees. Vespa velutina has been unintentionally introduced in southwestern France before 2004 and its widely spreading across the country was followed by an impressive colonization of several areas within mainland Europe and overseas. In Italy, V. velutina has been officially reported in June 2013 in Imperia province, Liguria region (northern Italy) and is now well established in the western part of this region and occasionally reported in Piedmont region. More recently, it has been spotted in Veneto, Lombardy and Tuscany regions. In order to investigate the phylogenetic relationships and the origin of Italian V. velutina nigrithorax specimens, we performed a phylogenetic analysis of thirty-three samples, collected in 2012, 2016, 2017 and 2018 from different sites (Veneto, Piedmont and Liguria regions) based on mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequence analysis. The phylogenetic analysis as well the haplotypes study confirmed the placement of 33 Italian specimens within a cluster containing the other European samples plus Chinese specimens collected in Jiangsu and Zhejiang. Our results strongly supported the view that the Italian specimens of V. velutina nigrithorax derived from the spreading southward of the V. velutina nigrithorax population initially established in France, which is also moving northward (Belgium, The Netherlands, Germany, United Kingdom).