西双版纳自然保护区昆虫病原真菌群落多样性及主要种群的生态位研究

Fungal Entomopathogens have attracted more and more attention because of their important role in the pest control, few is known on the community diversity and ecological niche of main population of fungal entomopathogens, and no standard statistics formula for the niche value evaluation. Xishuangbanna Nature Reserve is located in Yunnan province，it belongs to the lower altitude plateau forest ecosystem and the spot area for the biodiversity study, but no systematic study on the community diversity, and the ecological niche of main population of fungal entomopathogens were conducted here. So this project will community diversity and the niche characteristics of main population of fungal entomopathogens in different altitudes, habitats in different seasons throughout a year in tropical raining forest, evergreen broad-leaf forest, montane mossy evergreen broad-leaf forest, tropical bamboo forest, warm coniferous forest in Xishuangbanna Nature Reserve using the research techniques of fungal entomopathogens and community ecology. To make clear of the composition structure and its temporal and spatial rules of fungal entomopathogens by studying the community diversity. To verify the availability of niche theory in the community diversity study after the study of the niche characteristics and their seasonal dynamics. To get an available formula for the evaluation of the niche characteristics for the fungal entomopathogens by comparing the niche characteristics value from the different statistics formula. The study will provide good basis for the study on the biodiversity and the biological control fungal entomopathogens screen on forest pests.

昆虫病原真菌因其在害虫生物防治中的独特优势而备受关注，国内外对其群落多样性及种群生态位的研究报道甚少，亦无理想的生态位量化计算公式。西双版纳自然保护区为低纬高原热带雨林生态系统,被誉为生物多样性研究的热区，该区内有关昆虫病原真菌群落多样性及主要种群生态位还未见报道。本项目拟以西双版纳自然保护区热带季雨林、季风常绿阔叶林、苔藓常绿阔叶林、热带丛生竹林、暖热性针叶林为基地，于不同季节在不同海拔生境中系统调查和标本采集，研究昆虫病原真菌群落多样性，弄清该区域昆虫病原真菌群落组成结构及其时空分布规律；研究昆虫病原真菌主要种群的生态位特征及其季节动态，探明生态位理论在昆虫病原真菌群落结构研究中的可行性；比较不同计算公式对种群生态位宽度和生态位重叠值的评价效果，筛选出适合森林生态系统昆虫病原真菌生态位特征量化评估的计算公式。该研究将为昆虫病原真菌多样性及热带雨林生态系统害虫生防菌筛选提供依据。

本研究以西双版纳自然保护区不同生境为基地，按计划开展和完成了项目计划研究。（1）开展了昆虫病原真菌调查采集和分离，鉴定出昆虫病原真菌63种，其中中国新纪录种4种。（2）研究了昆虫病原真菌群落组成结构和多样性及其时空格局，发现不同生境中群落多样指数高低顺序为热带季雨林>季风性常绿阔叶林>石灰岩山地雨林低海拔地带>石灰岩山地雨林中海拔地带>热带丛生竹林>石灰岩山地雨林高海拔地带>暖热性针叶林；从时间分布上看，优势种细脚棒束孢于10月至次年1月和干热季节3月至5月发生流行，蚁生线虫草于6~10月和11月发生流行，球孢白僵菌于11月至次年7月发生流行，玫烟色棒束孢于10月至次年2月和干热季3~4月发生。（3）研究了昆虫病原真菌优势种及偶见种的生态位宽度，发现球孢白僵菌的寄主和时间生态宽度最大，蚁生线虫草最小。通过分析比较，筛选了适合昆虫病原真菌生态位宽度的Levins公式。（4）研究了昆虫病原真菌优势种及偶见种的生态位重叠，发现球孢白僵菌、玫烟色棒束孢、细脚棒束孢和蚁生虫草的时间生态位重叠度小于寄主生态位重叠度，与寄生态位重叠相反；通过分析比较，筛选了适合计算昆虫病原真菌生态位重叠的Morisita-Horn公式；（5）研究了优势种球孢白僵菌的遗传多样性，发现该区域球孢白僵菌遗传多样性丰富，且秋季遗传多样性最高，夏季最低；（6）生物测定了发生流行性强的昆虫病原真菌对马铃薯块茎蛾的毒力及防治作用。发现筛选的菌株YNMLBK171101对马铃薯块茎蛾蛹具有较强的致病力，在马铃薯块茎表面喷施毒土和在底部施加细脚棒束孢分生孢子毒土对马铃薯块茎蛾具有较良好的毒杀防治作用及生防作用。（7）生物测定了黄绿绿僵菌Ma130821对蛴螬的毒力及生防作用，发现该菌株对暗黑鳃金龟、小阔胫码绢金龟和白星花金龟3龄幼虫均具有较强致病作用，其分生孢子粉剂对白星花金龟3龄幼虫具有良好毒杀及生防作用。