Response of Five Cultivars to Grasshopper Herbivory: Implications for Monitoring of Invasive Grasses in Protected Areas.

Introduced grasses can aggressively expand their range and invade native habitats, including protected areas. is an introduced ornamental grass with 100+ cultivars of various invasive potential. Previous studies have demonstrated that the invasive potential of cultivars may be linked to seed viability, and some of the physiological traits, such as growth rate. Little is known, however, about whether these traits are associated with response of to insect herbivory, and whether plant tolerance and resistance to herbivory vary among its cultivars; which, in turn, can contribute to the invasive potential of some of cultivars. To address this issue, in our study we explored the response of five cultivars of to herbivory by grasshoppers. We demonstrated that plant responses varied among the cultivars during a season; all the cultivars, but "Zebrinus", demonstrated a significant increase in plant tolerance by the end of the growing season regardless of the amount of sustained leaf damage. Different patterns in plant responses from "solid green" and "striped/spotted" varieties were recorded, with the lowest plant resistance detected for "Autumn Anthem" in the cage experiment. Our results have important applications for monitoring low-risk invaders in protected areas, as well as for biotic resistance of native communities to invasive grasses.