Effects of vetiver oil components on termites: does nootkatone alter interindividual communication or motion ability?

Vetiver oil is extracted from the roots of an Indian native grass (Vetiveria zizanioides), which is known to be naturally resistant to arthropod pests and diseases. Vetiver oil consists of a complex mixture of more than 300 compounds, half of which are reported to be sesquiterpenoid constituents. Nootkatone, one of the components, is a mildly pungent sesquiterpene ketone with a distinctive grapefruit flavor, largely responsible for the unique aroma of vetiver oil. Our investigation aimed to test the effects of vetiver oil and its components on the Formosan subterranean termite, the major insect pests in the southern United States. The results showed that nootkatone and other natural components of vetiver oil negatively affect termite physiology and behavior, as a consequence of direct physical contact, ingestion, or exposure to the vapors. Especially interesting are the effects of nootkatone: in the presence of this compound termites were not able to dig tunnels or to build shelter tubes. We tested if nootkatone acts as simply an inhibitor of termite mobility or as a modifier of chemical signals important for communication between colony members.