Multifunctionality of herbivory-induced plant volatiles in chemical communication in tritrophic interactions.

Uninfested plants emit only trace quantities of volatiles (constitutively emitted plant volatiles). In contrast, some plants emit relatively large quantities of volatiles in response to herbivory (herbivory-Induced plant volatiles: HIPVs). Organisms belonging to different trophic levels use plant volatiles in context-dependent manners; consequently, volatiles can be adaptive, non-adaptive, or maladaptive to the emitter plants. In this review, we focus on the multifunctional aspects of HIPVs, which vary qualitatively and quantitatively in emitting plant species and infesting herbivore species, in plant-carnivore interactions, plant-herbivore interactions, and plant-omnivore interactions. Additionally, we review the evidence of plant-plant communication and its effects on tritrophic interactions involving plants, herbivores, and carnivores. Prospects on interactions mediated by plant volatiles induced by herbivorous arthropods are discussed.