The role of herbivore-induced plant volatiles (HIPVs) as indirect plant defense mechanism in a diverse plant and herbivore species; a review

Abstract

When plants are attacked by herbivores, they release plant volatiles called herbivore-induced plant volatiles (HIPVs) to the environment to communicate with higher trophic levels. HIPVs play different ecological roles such as plant-plant interaction, plant-herbivore interaction, tritrophic interaction and other related interactions. Attractiveness of HIPVs to natural enemies in a tritrophic interaction varies depending on species diversity. Under natural and multiple cropping systems, tritrophic interaction is expected to be more complex than single tritrophic interaction with one species per trophic level. In complex tritrophic interaction, diversity of different trophic levels affects attractiveness of HIPVs to natural enemies. From plant diversity point of view, HIPVs mixture emanating from herbivore-damaged multiple plant species are reported to affect behavioral responses and foraging behavior of natural enemies under laboratory and field conditions. Similarly, from herbivore diversity point of view, in nature, plants are commonly attacked by more than one herbivore species. Constituents of HIPVs vary between plants infested by multiple and single herbivore species and this affects the behavioral responses and foraging behavior of natural enemies. This paper reviews recent findings on the role of HIPVs as indirect plant defense in systems with simple tritrophic interaction, and in diverse plants species and diverse herbivore species.