球孢白僵菌种群在松林中的寄主转移及遗传多样性对松毛虫持续控制的影响

Host transfer of Beauveria bassiana population in pine stand ecosystem and impact of its genetic diversity on sustainable control of Masson's pine caterpillars.

通过林间接种式放菌及其后一周年的野外调查 ,从林间采集到 30种寄主昆虫及从土壤、落叶和气流中分离到 119株球孢白僵菌 .酯酶同工酶分析表明 ,它们属于 32个不同酯酶型 ,呈现出丰富的遗传多样性 .释放菌株所属的酯酶型 0 2包括从 11种昆虫上分离出的 18个菌株 ,表明林间释放的菌株已成功地在不同寄主昆虫种群中宿存下来 ,并以常发的地方病状态存在于松毛虫及松灰象甲等 12种昆虫种群之中 ;当林间目标寄主缺乏时 ,其它寄主可将食物链维系下去 .其它酯酶型分别包括 1～ 2 3个菌株 .一周年内的寄主转移动态结果表明 ,球孢白僵菌在松林生态系统中不同寄主间可转移寄生 .每个酯酶型中的菌株对松毛虫的毒力相差很大 .表明球孢白僵菌在松林中的延续和扩散流行不是 1条路线 ,每个酯酶型至少代表食物网上的 1条支链 .有些环节的寄主连接了不同的酯酶型 ,使松林中食物网变得十分复杂 .另外 ,从土壤、枯枝落叶层、林冠层和空气中分离到的球孢白僵菌分属于不同的酯酶型 ,表明松林中还存在着复杂的腐生食物链 。

In an anniversary investigation post inoculative release of Beauveria bassiana against Masson's pine caterpillars in a Masson's pine plantation,119 strains were isolated from 30 host insects,soil,litter and air.Based on an esterase isozyme analysis,all these strains were assigned to 32 esterase types,suggesting abundant genetic diversity.The esterase type 2 was assigned including 18 other strains from 11 different host insects,indicating that the released strain had successfully survived in different insect populations and persisted in enzootic condition in 12 insect populations including pine caterpillars and grey pine weevils.Other host insects could maintain the food chain when the target insect population was low.The other esterase types included 1～23 strains.The anniversary host transfer dynamics further revealed that B.bassiana could transfer among different host insects in the pine ecosystem.The virulence of the strains of each esterase differed substantially,which suggested that B.bassiana persisted and dispersed along more than one route,and each esterase stood for at least one branch in the food web.Some hosts connected different esterase types at nodal points,making the food web very complicated.In addition,the strains isolated from soil,litter,forest crown and air belonged to different esterase types,suggesting that a complex of saprophytic food chains existed in the plantation,which made the food web more complicated,and benefited the sustainable control of the Masson's pine caterpillar and other pest insects in the ecosystem.