Effects of herbivore-induced rice volatiles on the host selection behavior of brown planthopper, Nilaparvata lugens

It has been suggested that herbivore would react to volatiles produced by herbivore infested plant due to potential change, either positive or negative, in the acceptability of the host plant. This hypothesis was tested for the brown planthopper (BPH) in the laboratory. Sixteen components of the headspace volatiles from rice seedlings with different treatments were collected with SPME and Tenax-TA trap and analyzed with GC and GC-MS. Significant differences in volatile emissions were observed for rice plants with different treatments. Undamaged control plants, mechanically damaged plants and the plants infested by BPH for 1 or 2 d emitted much lower amounts of volatiles compared to the plants infested by BPH for 3 or 5 d. The plants infested by BPH for 3 or 5 d emitted several volatiles that were not detected in undamaged control plants, mechanically damaged plants or the plants infested by BPH for 1 or 2 d. Spodoptera litura infested plants released much higher amounts of volatiles than those in all other treatments, and the contents of several green leaf volatiles, methyl salicylate and terpenoids increased dramatically. In dual-choice flight tunnel experiments, adult BPH females showed no significant preference between the untreated healthy plants and mechanically damaged plants or the plants infested by BPH adult females. However, rice plants damaged by S. litura had a clearly repellent effects on BPH adult females compared to healthy undamaged plants, mechanically damaged plants or the plants infested by BPH.