A complex invasion story underlies the fast spread of the invasive box tree moth (Cydalima perspectalis) across Europe

Many recently established non-native insect species appear to be spreading across Europe significantly faster than before. The box tree moth (Cydalima perspectalis), a native to Asia, is illustrative of this trend. First recorded in 2007 in Germany, the moth has then colonized in less than 10years more than 30 countries in Europe and Asia Minor, causing significant damage to wild and ornamental Buxus trees. It has been hypothesized that the trade of ornamental box trees between China and Europe was responsible for the moth introduction while plant trade among European countries may have caused its rapid spread. To clarify the pest invasion history, we analyzed the genetic diversity and structure of its populations in the native and invaded ranges, using a 1495-bp fragment of the mitochondrial cytochrome oxidase I and II genes. Moth genetic diversity in Asia compared to the one observed in the invaded Europe and Asia Minor suggested that the invasive populations probably originated from eastern China. Furthermore, the high genetic diversity coupled with the spatial genetic structure in the invaded range suggested the occurrence of several introduction events, probably directly from China. Moreover, the spatial genetic structure in Europe and Asia Minor may also reflect secondary invasions within invaded range because of ornamental plant trade among European countries.