Spatial and temporal genetic variation of Drosophila suzukii in Germany

Native to Southeast Asia, the spotted wing drosophila (SWD), Drosophila suzukii Matsumura, rapidly invaded America and Europe in the past 20 years. As a crop pest of soft-skinned fruits with a wide range of host plants, it threatens the fruit industry worldwide, causing enormous economic losses. To control this invasive pest species, an understanding of its population dynamics and structure is necessary. Here, we report the population genetics and development of SWD in Germany from 2017–19 using microsatellite markers over 11 different sample sites. It is the first study that examines SWD’s genetic changes over 3 years compared to multiple international SWD laboratory strains. Results show that SWD populations in Germany are highly homogenous without differences between populations or years, which indicates that populations are well adapted, migrate freely, and multiple invasions from outside Germany either did not take place or are negligible. Such high genetic variability and migration between populations could allow for a fast establishment of the pest species. This is especially problematic with regard to the ongoing spread of this invasive species and could bear a potential for developing pesticide resistance, which could increase the impact of the SWD further in the future.