Interaction–information networks mediated by plant volatiles: a case study on willow trees

Volatiles from uninfested plants as well as those from plants infested by herbivores have been reported to potentially contain information that can be used by herbivorous arthropods, their carnivorous natural enemies, and plants. In this context, tritrophic interaction–information networks are expected. Here, as a case study of such a volatile-mediated network, we reviewed our recent studies on a naturally occurring tritrophic system of a willow tree (Salix eriocarpa), a leaf beetle (Plagiodera versicolora), and a predatory ladybird (Aiolocaria hexaspilota) mediated by volatiles from uninfested and infested willow trees. Ecological functions of uninfested and infested willow-shoot volatiles depended on receivers (i.e. leaf beetle adults, leaf beetle larvae, ladybirds, and conspecific tree). By studying such multifunctional aspects of plant volatiles in different natural willow fields, we would acquire a more comprehensive understanding of interaction–information networks.