Deterrence of herbivory by zinc hyperaccumulation in Thlaspi caerulescens (Brassicaceae)

SUMMARY Plants known as hyperaccumulators take up and sequester high concentrations of potentially toxic elements from metalliferous soils. We tested the hypothesis that zinc hyperaccumulation benefits plants by deterring herbivory. In laboratory feeding trials, three species of herbivores were allowed to choose between Thlaspi caerulescens (Brassicaceae) plants grown in low‐Zn and Zn‐amended culture solution. Locusts ( Schistocerca gregaria ), slugs ( Deroceras caruanae ), and caterpillars ( Pieris brassicae ) all showed significant preferences for plants with lower foliar Zn concentrations. Such differential feeding could result in selection pressures favouring the evolution of hyperaccumulation. The findings are also relevant to current proposals to exploit hyperaccumulation as a means of remediating metal‐contaminated soils.