Studies on insects community diversity in different altitudes tobacco fields in Longxian, Shaanxi Province | 陇县不同海拔烟田昆虫群落的多样性研究

chinois. 探究海拔因素对烟田昆虫群落结构及多样性的影响，分析不同海拔烟田害虫发生情况和天敌昆虫对害虫的控制情况，为烟田病虫害防治提供依据。在陕西陇县选择不同海拔烟田，采用棋盘式取样法抽取样株并记录烟株上各种昆虫的种类和数量，研究不同海拔烟田昆虫的时序动态、群落组织水平及相似性。烟田昆虫群落包括9目25科32种，其中害虫7目18科21种，天敌昆虫5目8科11种，主要害虫有烟蚜和斑须蝽，主要天敌昆虫有烟蚜茧蜂、丽草蛉、黑带食蚜蝇和七星瓢虫。高海拔烟田昆虫群落种类较丰富，群落结构较稳定，抵御环境变化与自我调节能力较强，多样性指数最高。中海拔和高海拔烟田昆虫群落相似性系数最高，各海拔烟田昆虫群落差异较大。8月中旬为各烟田害虫发生高峰期。烟蚜在田间出现时间较斑须蝽早，消失晚，田间数量较斑须蝽大。低海拔烟田烟蚜和斑须蝽数量较高海拔和中海拔烟田高。海拔高度差异及其所导致的物候差异是影响烟田昆虫群落结构的重要因子。

anglais. The research was to explore the influence of the altitude factors on insect community structure and diversity, and the occurrence of pests and the control of natural enemy insects, to provide scientific basis of control diseases and pests in tobacco fields at different altitudes. The tobacco plants samples were selected by adopting checkerboard sampling method, and the species and number of insects in each tobacco plant at different attitudes tobacco were recorded; insects time dynamics, community organization and similarity were researched in different altitudes tobacco fields in Longxian, Shaanxi Province, China. There were 32 species of insects belonging to 25 families, 9 orders in Longxian tobacco fields, including 21 species of pests (18 families, 7 orders) and 11 species of natural enemy insects (8 families, 5 orders). The dominant pests were Myzus persicae Sulzer and Dolycoris baccarum (Linnaeus); The natural enemy insects were mainly Aphidius gifuensis Ashmaed, Chrysopa formosa Brauer, Episyrphus balteatus De Geer and Coccinella septempunctata Linn. Insects species in high altitude tobacco fields were more than that of the low, its community structure was the stablest, capability of protected from environmental change and self-control was the strongest and diversity index was the highest. The similarity coefficient of insects community between the high and middle altitude tobacco fields was the highest. And a big difference of insect communities existed among various altitude tobacco fields. Pests reached its quantity peak in the period of mid August. Myzus persicae appeared in the tobacco fields-earlier than Dolycoris baccarum, while disappeared later. Its quantity was larger than Dolycoris baccarum. The numuber of Myzus persicae and Dolycoris baccarum in low altitude tobacco fields was more than that of high and middle altitude tobacco fields. Different altitudes and phenology are important factors that influence insect community structure in tobacco fields.