相关基金:Foundation item: This study was supported by the National Natural Science Foundation of China (30270166), Nature Science Foundation of Shanxi Province (20011101 ) and Director Foundation of Experimental Centre of Shenyang Normal University (SY200301 and SY200404). Acknowledgements: Special thanks are due to Mr. T0NG Yan-feng and Miss WANG Rong-rong, Institute of Entomology, Shenyang Normal University for their invaluable aids in this study.