Brown marmorated stink bugs are invading Europe: potential pathways of origin of the alien pest populations of Halyomorpha halys (Heteroptera, Pentatomidae)

The brown marmorated stink bug, Halyomorpha halys is an agricultural and household pest originating from Asia. In the last years it has become an invasive pest in North America causing severe economic losses to agricultural crops in the United States. Recently, H. halys has been retrieved in Europe (Switzerland, Germany, France, Hungary, and Greece) and, since September 2012, it has also been found in Italy. Tracing back the patterns of introduction and monitoring the spread of H. halys in the Italian territory in its initial phase of colonization will be useful in the view to implement better pest control strategies. The present study aims to identify the potential pathways of entry of H. halys by detecting the genetic diversity of specimens collected in Northern Italy, Southern Switzerland and Greece. The analyses of 1,175 base pairs of mitochondrial DNA cytochrome c oxidase I and II genes (cox1 and cox2) on more than 130 specimens led to the identification of ten haplotypes: one, scored in Italy and Greece, is the same found both in China and North America, while two haplotypes found in Switzerland and Lombardy are shared only with Chinese specimens. The other seven haplotypes are new and present high similarity with Asian haplotypes. Present data show that the introduction of the brown marmorated stink bug in Europe has occurred by means of multiple events, probably both from Asia and North America, and that H. halys is currently expanding its range in the European continent.