Distinct genotypes and phenotypes in European and American strains of Drosophila suzukii: implications for biology and management of an invasive organism

A clearer understanding of the structure of pest populations in newly invaded areas is a key step towards their effective management. Here, we use Drosophila suzukii as a model to highlight how populations from separate geographical regions differ in their genetic and phenotypic traits, including those associated with their invasiveness. New X-linked data indicate the presence of at most three D. suzukii genetic clusters in Europe, while North American populations are characterised by a larger genetic diversity. We found a likely new colonisation event from America to Italy and demonstrate that reference genomes from Italian and Californian populations lay in highly distant clusters. Comparative genomics indicate that these two genomes bear the traces of distinct evolutionary forces and are genetically distant, having diversified long ago in their native Asian range. Phenotypic studies further indicate that European and North American populations have differences in hatch rate, generation time, and parasitoid susceptibility. The observed genotypic and phenotypic differences likely represent a small fraction of the features unique to each of the two populations. The results provide some new insights towards both fundamental and management studies on invasive pests, particularly when findings are transferred across populations found in different geographical regions.