Plant mediated interactions between herbivores from different feeding guilds (Myzus persicae and Leptinotarsa decemlineata) on potato (Solanum tuberosum)

Herbivory induces defense responses in plants that alter plant traits, affecting insect fitness and behavior. Herbivores that share a host-plant can interact indirectly even if spatially or temporally distant. Jasmonic (JA) and salicylic (SA) acid play a central role in regulating plant defenses. Induction of these pathways is closely associated with the feeding guild of the herbivore. This study investigated how the co-occurrence of herbivores from different feeding guilds, Myzus persicae (Sulzer) and Leptinotarsa decemlineata (Say), could lead to differential responses in plant phytochemistry and herbivore performance and host-plant preference when feeding on potato, Solanum tuberosum L. In laboratory bioassays M. persicae performed better when feeding alone, but the presence of M. persicae did not impact L. decemlineata performance. Interestingly, when given a choice, M. persicae preferred host-plants that were damaged by L. decemlineata, while L. decemlineata preferred undamaged plants. A field study was conducted to evaluate the consequences of induced defenses due to multi-herbivory on tuber yield and whether laboratory performance results were consistent in an agricultural setting. Compared to laboratory bioassays, herbivore interactions were diminished in the field with no observed effect on yield. Differences in volatile emissions, glycoalkaloid, and JA/SA content are also discussed for each trial. Further studies investigating the qualitative and quantitative strength of feeding guild-plant interactions could provide a more thorough understanding of resistant traits and improve pest management products and practices.