Stanleya pinnata (prince's plume) can hyperaccumulate the toxic element selenium (Se) up to 0.5 percent of its dry mass in its natural habitat in the western United States. In a two-year manipulative field experiment to test whether S. pinnata uses Se as an elemental defense against one of its native mammalian herbivores, the blacktailed prairie dog (Cynomys ludovicianus), plants with high Se concentrations had higher survival rates and less herbivory than low-Se counterparts when planted in black-tailed prairie dog towns. These results give better insight into the evolution of plant Se hyperaccumulation, suggesting a role for herbivory as a possible selection pressure. From an applied perspective, plants that accumulate Se may be cultivated for phytoremediation or as fortified foods, and this study helps assess the associated risk of Se moving up the food chain.
Colin Quinn, Colorado State University, Fort Collins, Colorado