Although five different classes of insect herbivore-produced elicitors of plant volatiles have been identified, this is only a part of the complex, chemically mediated interactions between insect herbivores and their host plants. The defensive reactions of the plant, following physical injury by the herbivore, are influenced by a multitude of factors including, but not necessarily limited to, the elicitors and numerous other herbivore-associated molecules, as well as microbes on the plant surface that may alter plant defensive pathways. Ultimately, a thorough and accurate understanding of the chemical ecology of insect-plant interactions will require a more holistic approach, taking into consideration the ecological and physiological context in which a plant perceives and responds to herbivore-associated signals.