中文摘要：

2009年在浙江千岛湖小皱蝽种群中发生了由球孢白僵菌引起的流行病。利用ISSR分子标记对流行区内的132株球孢白僵菌进行指纹图谱分析,以探讨昆虫自然流行病的发生与病原种群异质性之间关系。8个ISSR引物共扩增出65个位点,其中多态位点数为58个,占89.23%;总的遗传多样性和Shannom信息指数分别为0.220 1和0.352 1,表明引起小皱蝽流行病的球孢白僵菌种群具有较高的遗传多样性,而且球孢白僵菌种群遗传多样性随寄主种类增加而增加。UPGMA聚类分析表明：在遗传相似系数0.783将研究的菌株划分为7个分支,其中CladeⅠ和Ⅱ中共有119株,占总菌株数的90.15%。亚种群间遗传分化系数和基因流分别为0.463 0和0.290 0,说明亚种群间存在较高的分化。研究结果表明小皱蝽流行病无流行中心,引致本次小皱蝽流行病的球孢白僵菌种群为多系的异质种群。

英文摘要：

An epizootic of the Chinese stinkbug,Cyclopelta parva, caused by Beauveria bassiana, occurred in 2009 in Qiandao Lake National Forestry Park, eastern China. To study the relationship between the occur-rence of natural epizootic in insect population and population heterogeneity of fungal entomopathogens, finger-print analysis of 132 isolates of Beauveria bassiana from the epidemic area was performed with the method of inter-simple sequence repeats（ ISSR） . Sixty-five scored DNA bands were generated by eight primers, and fifty- eight of 65 loci（ 89.23%） were polymorphic.The total genetic diversity（ Ht ）was 0.220 1 and Shannon＇s infor-mation index（Is ）was 0.3521 , suggesting a high rate of genetic diversity of the prevailing strains of B. bassiana. Moreover,the population genetic diversity increased with the species ol the host insect.A hierarchical dendro-gram constructed with UPGMA method revealed a high differentiation ol a Jaccard similarity coefficient ol 7 1 % -100% ,and the 132 isolates were clustered into seven clades with a similarity ol 78.3%.They differentiated in-to two main clades（ Ⅰ and Ⅱ ） including over 9 0 % ol all the strains which caused the epizootic.The subpopula-tion differentiation was relatively high（ GST = 0.463 0 ）and the gene flow was low（ Nm = 0.290 0） ,suggesting a generally higher genetic differentiation within subpopulations. Based on the analyses above, there has not been a center ol the outbreak ol the epizootic ol the Chinese stinkbug,and the population ol B. bassiana was polyphyletic and heterogeneous.