Abstract: By the methods of headspace enrichment and GC-MS, this paper studied the composition and quantity of the volatiles emitted from two transgenic Bt  maize varieties (5422Bt1 and 5422CBCL) and their homologous regular variety (5422) after the feeding by Spodoptera litura. As for the intact plants, the volatiles emitted from variety 5422 were (E)-β-ocimene, linalool, (3E)-4,8-dimethyl-1,3,7-nonatviene (DMNT), and (E)-β-farnesene, those from 5422Bt1 were linalool and DMNT, while 5422CBCL only emitted linalool. After the feeding by S. litura, a total of twelve volatiles including terpenoid, alcohol, ester, and indole were emitted from 5422 and 5422Bt1, and ten volatiles were emitted from 5422CBCL, with a lack of (Z)-3-hexen-1-yl acetate and nerolidol. The kinds and quantities of terpenoids emitted from the test three varieties were increased significantly, with eight kinds increased for varieties 5422 and 5422Bt1, and seven kinds increased for 5422CBCL. The emitted amounts of linalool and DMNT from the Bt maize varieties were
 higher than those from the regular variety, while the emitted amounts of other volatiles were in reverse. Especially for (E)-β-farnesene, its emitted amount from the Bt maize varieties was much lower than that from the regular variety. It was obvious that after the feeding by S. litura, the composition and quantity of the volatiles emitted from the Bt maize varieties differed with those emitted from the regular variety, and there was a difference between varieties 5422Bt1 and 5422CBCL.

Key words: Spodoptera litura, Bt maize, volatiles, composition, quantity, variable weight model, ecological security, early warning, Zhoushan Islands.