Occurrence and genetic diversity of new populations of Halyomorpha halys in Europe

Originating in East Asia, the brown marmorated stink bug, Halyomorpha halys, has established in North America and Europe where it has become an urban and agricultural pest. Although initial populations in Europe were only reported in Switzerland, H. halys has expanded its range to include areas in France, Greece, Hungary, and Italy. Analysis of a portion of the mitochondrial COI gene was used to evaluate the genetic diversity of these populations and to investigate the movement and spread of different COI haplotypes of this pest in Europe. A total of 9 haplotypes are now confirmed in Europe. Four of these haplotypes have not been previously reported elsewhere, and one of these haplotypes has not been previously reported in Europe but is known from Korea. The H. halys population in Greece was the most diverse, with 7 of the 9 haplotypes occurring in the area of collection. Haplotype H1, which is known from North America, Italy, and China, was also present in samples collected in France, Greece, Hungary, and Switzerland. In fact, the H1 haplotype was the dominant haplotype detected in Budapest, Hungary and also occurred frequently in the samples from Athens, Greece. Patterns of haplotype diversity indicate the movement of successful invasive populations to generate secondary invasions within Europe (‘bridgehead effect’), as well as the occurrence of multiple invasions from Asia. Scenarios regarding the movement and spread of particular haplotypes in Europe are discussed