D3205: Species specific HIPVs influence foraging of both generalist and specialist herbivores as well as natural enemies

Olfactory cues plan an integral role in mediating below-ground interactions where other senses are limited. Herbivore induced plant volatiles (HIPVs) cue natural enemies to the presence of prey and signal to conspecific herbivores the presence of intraspecific competition. In this study we evaluate the role of root HIPVs from Diaborica undecimpunctata, a generalist on maize, as well as Diabortica virgifera virgifera, a specialist on maize in facilitating host plant selection by both natural enemies and heterospecific herbivores. For this study we quantify herbivore and natural enemy attraction to volatile cues produced by the roots of maize. Previous literature in cucumber, maize, poplar, and citrus highlights the important functions of root volatiles in mediating predator prey interactions. We predict there to be species specific interactions among both the herbivores as well as the natural enemies. Our predictions were incorrect in most cases, where it seemed that volatiles did not have a significant effect of behavior. The exception being when Diabortica virgifera virgifera was exposed to damage from its own herbivory. The specialist species significantly preferred undamaged plants versus planted damaged by conspecifics. The other exception being with the natural enemy, Steinernema riobrave, where the nematodes avoided plants damaged by specialist herbivory. These results suggest that specialist herbivores may induce volatiles that offer a selective advantage by deterring competitors or predators.