Herbivore-induced responses mediate feeding guild interactions in potato (Solanum tuberosum L.)

Plant traits can influence the behavior, abundance, and distribution of their associated herbivores. Inducible defenses are one way that plants can alter herbivore activity. Research has shown that plants respond to attacking herbivores via signal transduction defense related pathways, often specific to the herbivore’s feeding guild. However, plants are generally attacked by an array of herbivores, both sequentially and simultaneously, and defense mechanisms tailored for one type of herbivore may not effectively defend against other types of herbivores. In this study, we explored how individual plants respond to herbivores from two feeding guilds and how induced plant responses impact the performance and host-plant preference of simultaneous and sequential herbivores. The Colorado Potato Beetle (CPB), Leptinotarsa decemlineata Say, a major agricultural pest of potato (Solanum tuberosum L.), is a foliar-feeding herbivore that uses chewing mouthparts to masticate leaf tissue. Whereas Green Peach Aphids (Myzus persicae Sulzer) are phloem-feeding herbivores that use piercing and sucking mouthparts to penetrate the leaf surface and feed directly on the phloem contents of their hosts. These herbivores elicit different plant responses, and feeding by one could potentially affect the behavior and performance of the other. We found that CPB feeding negatively impacted aphids regardless of feeding sequence. Interestingly, aphids were still more attracted to CPB-damaged plants.  Using gas chromatography-mass spectrometry (GC-MS) we were able to show that the volatile profiles differed between herbivore damaged and undamaged plants, indicating that insects from different feeding guilds indirectly interact on the leaf interface via herbivore-induced plant responses.