Range expansion of the Argentine ant (Linepithema humile) into Virginia: Genetic evidence, supercolonial patterns, and viral infection patterns

Prompted by a series of iNaturalist records beginning in 2019, we investigated a potential range expansion of the invasive Argentine ant (Linepithema humile) in Virginia. Our study examines population genetic structure, supercolonial organization, foraging behavior, and RNA virus infection patterns. Mitochondrial DNA analyses indicate that these Virginia populations share haplotypes with other U.S. populations, suggesting a domestic range expansion rather than a novel introduction from overseas. However, the absence of known populations between these new sites and the nearest records in North Carolina suggests either a sampling gap or long-distance jump dispersal. Aggression assays are ongoing to determine inter-site colony boundaries and supercolonial structure, which may shed light on the ants’ invasion history. Virus screening revealed a relatively simple RNA virus community, with Linepithema humile virus 1 (LHUV-1) being particularly prevalent. Notably, some populations harbor viruses known to be pathogenic to honey bees. These findings provide essential insights for developing targeted pest management strategies and highlight the broader ecological and economic impacts of Argentine ant invasions beyond direct competition with native species.