Leaf herbivory induces resistance against florivores in Raphanus sativus

Abstract

Florivory can have significant negative effects on plant fitness, driving selection for resistance traits in flowers. In particular, herbivory to leaves may induce resistance in flowers because herbivores on leaves often become florivores on flowers as plant ontogeny proceeds. The literature on inducible resistance in floral tissues is limited, so we used a series of experiments to determine whether prior leaf damage by Spodoptera exigua (Hübner) caterpillars affected florivore preference and performance on wild radish (Raphanus sativus L.). We found that Spodoptera exigua larvae preferred petals from control plants versus petals from plants exposed to prior leaf damage, and that larvae gained more mass on petals from control plants, although this depended on the presence of anthocyanins in the petals. Our results suggest that leaf damage can induce changes in petals that reduce Spodoptera exigua larval fitness.