不同地理种群尖音库蚊复组抗性动态和遗传多样性

Resistance dynamics and genetic diversity of Culex pipiens complex(Diptera:Culicidae)from different geographical locations in China

通过生物测定、蛋白质电泳和等位酶分析等方法对5个不同地区的尖音库蚊复组蚊虫Culex pipienscomplex的抗性水平、种群中非特异性酯酶基因表型分布和种群遗传多样性进行了研究。不同地理种群的抗性检测结果表明:5个种群分别对敌敌畏、对硫磷、氯菊酯和溴氰菊酯的抗性较高,对残杀威、巴沙和胺菊酯的抗性较低;朝阳种群对敌敌畏抗性最高(55.7倍),武汉种群次之;佛山种群对氯菊酯和溴氰菊酯的抗性比率高达123倍和23.9倍。酯酶电泳结果显示:5个种群间酯酶多态性存在差异,广州和佛山两个库蚊种群酯酶表型多态性最高,有B1,A2-B2,A8-B8,A9-B9,B10和A11-B11等6种酯酶表型,提示高活性酯酶是主要的抗性机制。群体遗传学研究表明:每位点平均等位基因数(A)为2.76,平均多态位点百分率(P)为64.45%,平均预期杂合度(He)为0.1943,种群间遗传分化系数(Fst)值为0.10,平均基因流(Nm)=2.57,说明5个种群有较丰富的遗传多样性,种群内遗传多样性高于种群之间。据此推测,种群间可以通过迁徙等方式进行基因交流,使得遗传结构、抗性水平朝一致性方向变化。本研究对我国尖音库蚊复组蚊虫的综合治理有一定指导意义。

The resistance levels to various insecticides, the distribution of the esterase genotypes, and the genetic diversity of five different field samples of Culex pipiens complex were studied by bioassay, protein electrophoresis, and the analysis of resistant alleles. Using the sensitive lines S-LAB as the control, the bioassay results indicated that the five Cx. populations showed higher resistance against dichlorovos, parathion, deltamethrin and permethrin, but lower resistance against propoxur, bassa, and tetramethrin. Chaoyang population had the highest resistance （55.7-fold） to dichlorovos, followed by Wuhan population. Foshan population also had higher resistance levels with 123-fold to permethrin and 23.9-fold to dehamethrin. The esterase electropboresis indicated that the five Cx. populations showed different phenotype polymorphisms. The esterase of the Cx. populations from Guangzhou and Foshan exhibited the highest phenotype polymorphism with B1, A2-B2, A8-B8, A9-B9, BIO and All-Bll, suggesting that the over- produced esterases be the main mechanisms for resistance. Population genetics results indicated that the number of average allele, average polymorpbism site, average expected heterozygosity, differentiation coefficient （Fst） and average gene flow （Nm） were 2.76, 66.45%, 0. 1943, 0.10 and 2.57, respectively. The results showed that the five Cx. populations have a wealth of genetic diversity and the genetic diversity within populations is higher than that between populations. It is so inferred that the genetic diversities and the resistance levels became more identical through gene communication among the field populations by migration or others. This study may provide a guide to integrated pest management for Cx. pipiens complex in China.