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International audience; 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 10 years 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.

IUFRO WP 7.03.07 "Population Dynamics of Forest Insects",IUFRO WP 7.03.06 "Integrated management of forest defoliating insects",IUFRO WP 7.03.13 "Biological control of forest insects and pathogens"&Forest Research Institute in Sękocin Stary, PolandRegional Directorate of State Forests in Gdańsk, PolandUnder the honory patronage of the Ministry of Environment; During the recent decades, ornamental plant trade has triggered the introduction of alien invasive insects in Europe. An ever increasing number of these alien species originates from Asia, such as the box tree moth Cydalima perspectalis, a species native of China, Korea and Japan, which has recently been introduced into Europe. Since its first observation in Germany in 2007, the box tree moth has spread rapidly all over Europe, causing important damage on commonly planted ornamental box trees. The ornamental trade between Europe and China is hypothesized as the pathway of its primary introduction while the trade within Europe could have favored its rapid spread. In order to disentangle invasion pathways, samples of C. perspectalis were collected in China, Korea and in 13 of the 25 invaded European countries. We analyzed 174 sequences of mitochondrial markers COI and COII from the native and invaded areas in order to check the genetic variability, and to develop a preliminary phylogeographical approach. In the Asian populations, we observed 7 haplotypes divided into 3 haplogroups, and 4 of those haplotypes were also observed in Europe. Our preliminary results did not show evidence of genetic structure in the native range, which did not allow to define the potential donor regions but the presence of several Asian haplotypes in Europe in addition to a low but significant geographical structure is in favor of multiple introductions. Nevertheless, more populations need to be sampled in the area of origin together with the definition of more polymorphic markers in order to better understand the invasion pathways of C. perspectalis.

International audience