Invasive ants and their co-introduced viral pathogens

Specimens intercepted at their port of entry (PoE) play a key role in any biosecurity program around the world. They provide critical information to assist in evaluating invasion risk (e.g., pathway, commodity or taxa composition) and also serve as useful proxies to predict species establishment probability. In this study we profiled RNA viruses carried by individual fire ants intercepted at Japanese ports using metatranscriptomic sequencing to establish a repertoire of co-transported viral pathogens with their fire ant hosts. In addition to Solenopsis invicta viruses that dominate the contigs, all sequenced fire ant workers were found to carry at least one pathogenic honey bee virus, raising the concern of potential impacts of these co-transported viral pathogens, if established, on honey bees and other pollinators. Viruses associated with honeydew-producing insects or other insects/invertebrates as well as plants were also detected. While the fate and impacts of these co-transported viral pathogens remain to be determined, our results demonstrate that invasions are not the product of single-species introduction and highlight the previously overlooked value of PoE specimens, especially for forecasting potential new and emerging pathogens that may arrive with their hosts.