Condensed tannin in Eragrostis chloromelas leaves deters feeding by a generalist grasshopper

Abstract

We investigated the feeding responses of a generalist grasshopper, the brown locust (Locusta pardalina), to leaves of the grass Eragrostis chloromelas differing in polyphenol content. For three specimens of E. chloromelas, the presence of condensed tannin in epidermal cells was confirmed by histochemical staining, while two specimens lacked polyphenols. Locusts selected the leaves of tannin‐free plants for feeding significantly more frequently than leaves from plants containing tannins. Findings suggest that the food choice of some locusts was affected by the presence of tannins, although variability in feeding responses among individuals was apparent. However, we cannot exclude the possibility that other differences existed between the specimens.

Additional index words:

• Allelochemicals
• insect herbivory