Viral sequence polymorphism as a surrogate data set to assess attributes of an invasive insect population

RNA virus genomes evolve at rates many-fold greater than that of multicellular organisms serving as hosts. Thus, sequence polymorphism of a virus could serve as a surrogate data set to discriminate recently separated populations of an invasive insect species. Homalodisca vitripennis reovirus (HoVRV) was used as a surrogate to assess population structure of the glassy-winged sharpshooter (Homalodisca vitripennis), an invasive species detected in California ~20 years ago. HoVRV nucleotide sequence polymorphism revealed a bottleneck in the introduced population, yielded population age estimates consistent with timing of glassy-winged sharpshooter discovery in California, and suggested gene flow among locations within the native range in the southeastern U.S. but not between native and introduced populations. Collectively, the data support use of a virus surrogate to define critical attributes of invasive species populations, with the caveats that life history of the surrogate must be closely linked to that of the host and the virus is benign such that infected individuals are not at a selective disadvantage.