ROLE OF RICE VOLATILES IN THE FORAGING BEHAVIOUR OF CYRTORHINUS LIVIDIPENNIS REUTER

Experiments were conducted in laboratory to study the impacts of rice genotypes and nitrogen levels on the preference of the egg predator, CyTtorhinuc liuidipennk , for eggs of brown planthopper(BPH) , Nilaparvata lugem ( SGl) , and their relation to the rice volatiles. In two-choice tests, the female predators showed daerent preference for BPH eggs on different rice genotypes, but not for BPH eggs on rice plants treated with different levels of nitrogen. The olfactory response test revealed that more predator oriented to the odour from healthy rice plants compared with the plain air (control) ;the predator preferred BPH nymph-damaged plants to healthy plants, and BPH female adult-dam- aged plants to BPH nymph-damaged plants. The comparative studies between rice genotypes and nitrogen levels indi- cated that there were obvious differences in attractiveness to the predator between rice genotypes, while there was no significant difference between rice plants treated with different levels of nitrogen . The results showed that rice volatiles played an important role in mediating the foraging behaviour of C. liwidipennis . Implications for augmenting the effec- tiveness of natural enemies by adjusting rice attributes and cultural practices are discussed.