Abstract: 【Aim】 To understand the effects of defense responses in tomato plants induced by Frankliniella occidentalis (Pergande) on behavioral responses of Bemisia tabaci (Gennadius) B-biotype, and to explore the interspecific competition mechanisms between F. occidentalis and B. tabaci B-biotype. 【Methods】 Using Y-tube olfactometer and choice test methods, we studied the differences of host preference and behavioral responses of B. tabaci on different plants under different treatment combinations, including the undamaged plants (CK) vs the plants damaged by B. tabaci (B), CK vs the plants damaged by F. occidentalis (F) and the plants damaged by B. tabaci plants (B) vs the plants damaged by B. tabaci and F. occidentalis (B+F), and identified the volatiles of tomato plants in different treatments by GC-MS. 【Results】 The olfactory responses of female B. tabaci adults were not significantly different between CK vs B and CK vs F treatment combinations, whereas strong selection reaction of female adults of B. tabaci to tomato plants damaged only by B. tabaci was found in B vs B+F treatment combination (P<0.01). The results of choice test showed that B. tabaci adults were both strongly attracted by the undamaged plants and oviposited on them in CK vs B and CK vs F treatment combinations (P<0.01), whereas B. tabaci adults prefered the plants damaged only by B. tabaci and oviposited on them in B vs B+F treatment combination (P<0.01). The results showed that 9 kinds of plant volatiles were collected, 5 of which were alkenes, accounting for 90% of the total volatiles by GC-MS. β-Myrcene, which shows strong attractiveness to B. tabaci, remarkably reduced and β-phellandrene, which shows rejection to B. tabaci, remarkably increased in the plants damaged by both herbivores, compared to the plants damaged only by B. tabaci. 【Conclusion】 The defense responses in tomato plants induced by F. occidentalis have a great effect upon host preference and behavioral responses of B. tabaci.

Key words: Frankliniella occidentalis, Bemisia tabaci B-biotype, tomato plant, plant defense response, behavioral responses, herbivore-induced plant volatiles (HIPVs)