麦田昆虫群落的结构与时序动态

采用目测法和网捕法 ,通过对小麦整个生长季节内昆虫群落的系统调查 ,共查得昆虫11目 2 3科 36种 ,其中捕食性昆虫有 4目 5科 12种、寄生性昆虫有 2目 3科 4种、植食性昆虫有 5目 12科 15种、粪食性等其他类昆虫有 1目 3科 5种。在捕食性天敌昆虫中 ,瓢虫的种类和数量最多 ,其次为草蛉和食蚜蝇 ;在寄生性天敌昆虫中 ,蚜茧蜂为优势种 ,其次为寄蝇 ;在植食性昆虫中 ,麦长管蚜为绝对的优势种 ,其次为赤须盲蝽、灰飞虱和麦蓟马。天敌昆虫对害虫具有明显的跟随现象 ,不能有效地控制麦长管蚜的发生与危害。依据昆虫群落的组成与结构 ,结合小麦生育期 ,采用最优分割法将麦田昆虫群落动态划分为 5个阶段 ,并指出不同阶段昆虫群落特点及相应的害虫防治策略。

Seasonal dynamics and structures of insect communities in wheat fields

Systematic investigation and analysis of insect communities in wheat fields was carried out from April to July,2003.The results indicated that there were 11 orders,23 families,36 species of insects including 4 orders,5 families,12 species of predators; 2 orders,3 families,4 species of parasitoids; 5 orders,12 families,15 species of phytophagous insects ,and 1 order,3 families,5 species of others.Ladybird beetles were the most abundant in species and quantity among the predators,and green lacewings and syrphid flies were secondly.Among the parasitoids,the aphid parasitoid was the most dominant and then the larvaevorids.The English grain aphid Macrosiphum avenae was the most dominant,and the rice leaf bud Trigonotylus ruficornis,the small brown planthopper Laodelphax striatellus and the rice phloeothrips Haplothrips aculeatus were the next.Natural enemies occurred after pest insects and could not control the English wheat aphid efficiently.Based on the component structure of insect communities and wheat developmental period,the seasonal dynamics of insect communities in the wheat fields was divided into five periods using the best division method of sequent samples,and the community characteristics and control strategies in different periods were given.