Utilization of a wide range of exotic plant species by an exotic, Solidago-specialist aphid, Uroleucon nigrotuberculatum (Hemiptera: Aphididae).

This article investigates the recent host range expansion of the exotic red goldenrod aphid, *Uroleucon nigrotuberculatum* (Hemiptera: Aphididae), introduced from North America to Japan. Originally a specialist feeding exclusively on *Solidago* species in its native range, this aphid has been found in Japan utilizing a broader range of exotic Asteraceae plants beyond *Solidago altissima*, including *Taraxacum officinale* and *Senecio vulgaris*. Molecular phylogenetic and morphological analyses confirmed that aphids collected from various exotic plants belong to the same species, showing no host-associated genetic differentiation. Field inoculation experiments demonstrated that aphids from *S. altissima* can survive and reproduce on multiple exotic plant species, suggesting ecological host expansion without genetic divergence. These findings highlight the potential for invasive herbivores to broaden their host use in introduced regions, which may facilitate their spread and impact on novel ecosystems.