Going global - genomic insights into insect invasions.

The spread of invasive insect pests is becoming an increasing problem for agriculture globally. We discuss a number of invasive insects, already of major economic significance that have recently expanded their range to become truly global threats. These include the noctuid moths Helicoverpa and Spodoptera, whose caterpillars have long been among the worst pests in their native Old and New World habitats, respectively, and the whitefly Bemisia, a major vector of plant virus diseases. Importantly, genomic resources for these species have recently become available, allowing research to move beyond the restrictions imposed by earlier approaches limited to a single or few mitochondrial and nuclear markers, to employ genome-wide genotyping and resequencing protocols. These studies have shown hybridisation within the various species complexes, identified regions under selection in agricultural environments, and enable monitoring of genes important as biosecurity risks through introgression into established populations free of the genes. In all cases studied, global trade has emerged as the probable cause of insect spread, making it ever more important that biosecurity protocols and agencies work with researchers to make the most effective use of emerging genomic resources and tools.