With the introduction and establishment of exotic species, most ecosystems now 
contain both native and exotic plants and herbivores. Recent research identifies 
several factors that govern how specialist herbivores switch host plants upon 
introduction. Predicting the feeding ecology and impacts of introduced 
generalist species, however, remains difficult. Here, we examine how plant 
geographic origin, an indicator of shared co-evolutionary history, influences 
patterns of host use by a generalist, invasive herbivore, while accounting for 
variation in plant availability. The brown marmorated stink bug, Halyomorpha 
halys, is a highly polyphagous Asian herbivore and an economically important 
invasive pest in North America and Europe. In visual surveys of 220 plant taxa 
in commercial nurseries in Maryland, USA, H. halys was more abundant on 
non-Asian plants and selected these over Asian plants. The relationship between 
the relative use of plants and their availability was strongly positive but 
depended also on plant origin at two of our three sites, where the higher 
relative use of non-Asian plants was greatest for highly abundant taxa. These 
results highlight the importance of considering both plant origin and relative 
abundance in understanding the selection of host plants by invasive generalist 
herbivores in diverse, natural and urban forests.