B型烟粉虱田间种群对毒死蜱和敌敌畏抗性的生化机制

通过增效剂生物测定和生化分析,探讨了采自福建省的B型烟粉虱Bemisia tabaci 6个田间种群对毒死蜱和敌敌畏抗性的生化机制。结果表明：与敏感品系SUD-S相比,6个田间种群对毒死蜱和敌敌畏分别具有54.53～78.43倍和6.23～11.25倍的抗性。TPP、PBO和DEM对毒死蜱的增效比分别为3.61～24.94倍、1.14～1.76倍和1.04倍,对敌敌畏的增效比分别为1.67～2.64倍、1.33～1.65倍和1.09倍,表明羧酸酯酶的解毒代谢在烟粉虱对毒死蜱的抗性中起着重要作用。烟粉虱抗性种群乙酰胆碱酯酶的K_m值是敏感品系的1.83～4.0倍,V _max值是敏感品系的0.34～0.62倍; 敏感品系乙酰胆碱酯酶的活性在底物浓度大于1.0 mmol/L时受抑制,抗性种群乙酰胆碱酯酶的活性在底物浓度大于16 mmol/L时受抑制;抗性种群乙酰胆碱酯酶对敌敌畏和毒死蜱的敏感度分别比敏感品系低119.92～161.33倍和10.11～14.24倍,表明烟粉虱田间抗性种群乙酰胆碱酯酶可能已发生了变构,由变构引起的乙酰胆碱酯酶不敏感是烟粉虱田间种群对毒死蜱和敌敌畏产生抗性的重要原因。结果提示,乙酰胆碱酯酶不敏感性和羧酸酯酶的解毒代谢在烟粉虱对毒死蜱的抗性中均起着重要作用,而乙酰胆碱酯酶不敏感性在对敌敌畏的抗性中起重要的作用,多功能氧化酶和谷胱甘肽S转移酶在烟粉虱对毒死蜱和敌敌畏抗性中所起的作用不大。     

Glutathione S-transferase detoxification as a potential pyrethroid resistance mechanism in the maize weevil, Sitophilus zeamais

Insecticide resistance patterns among 16 Brazilian populations of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), were recognized by surveying resistance to three organophosphates (chlorpyrifos‐methyl, malathion, and pirimiphos‐methyl) and three pyrethroids (cypermethrin, deltamethrin, and permethrin). Two population clusters were obtained: one with three populations (Bragança Paulista, Cristalina, and Nova Andradina) showing low frequency of cypermethrin resistance (13–36%) and negligible frequency of deltamethrin resistance (2–9%); and another with six populations (Campos dos Goytacazes, Ivinhema, Patos de Minas, Penápolis, Uberlândia, and Venda Nova) showing low to negligible levels of pyrethroid resistance (0–23%). The remaining seven populations, including a susceptible, and a DDT‐ and pyrethroid‐resistant reference populations (Sete Lagoas and Jacarezinho, respectively), were significantly different from each other and from the two recognized clusters. In contrast with pyrethroid resistance, organophosphate resistance was negligible except for chlorpyrifos‐methyl in two populations (Fátima do Sul and Penápolis). There was no correlation between geographic distance and the Mahalanobis distance estimated from the resistance pattern ordination of the populations by canonical variate analysis, suggesting local selection and/or broad dispersal of resistant populations by grain trade. The results of biochemical in vitro studies measuring the activity of detoxification enzymes (esterases and glutathion S‐transferases) in conjunction with canonical correlation analysis suggest a major involvement of enhanced conjugation by glutathione S‐transferases (> 2‐fold increase) in pyrethroid resistance and, in the case of cypermethrin resistance, enhanced phosphotriesterase activity.     

ESTERASE PHENOTYPES IN NATURAL POPULATIONS OF CULEX PIPIENS PALLENS (DIPTERA: CULICIDAE) AND THEIR VARIATIONS UNDER INSECTICIDE SELECTION*

Abstract Three populations of Culex pipiens pallens Coquillett, from Hangzhou, Linhai and Jinhua, were determined for their probability of resistant esterase phenotypes. Further, each population was selected with dipterex, chlorpyrifos, temephos and malathion at a given dose of 60%‐70% mortality and was determined for the variation of resistant esterase phenotypes in its offspring. The results indicated that esterase B₁ phenotype was dominant in three populations although different natural populations have a different probability distribution of esterase B phenotypes. Insecticide selection showed that various esterase loci seemed to have different selective advantages under different insecticide pressures. The esterase B₁ phenotype was selected under temephos, and the esterase B₂ phenotype was selected under dipterex and chlorpyrifos. Except for the esterase B₁ phenotype, the heterozygote of B₁/B₂ phenotypes was detected under malathion pressure. These results are discussed in relation to the selective advantages of esterase genes to OP pressure and mosquito control strategies.     

SIGNIFICANCE OF PASSIVE MIGRATION IN EVOLUTION OF INSECTICIDE RESISTANCE IN THE MOSQUITO CULEX PIPIENS (DIPTERA: CULICIDAE)

In order to determine the combined effects of migration and gene flow on evolution of insecticide resistance in the mosquito Culex pipiens, four samples were collected in China, among which two were collected along the railway from Beijing to Guangzhou. Bioassay data showed that the resistance levels of the four populations to dichlorvos were high and to parathion moderate as compared with the susceptible strain and there was no significant difference among the four populations to the same organophosphate (OP) insecticide. Starch electrophoresis was done to identify the frequency of known overproduced esterases and to analyze genetic diversity among various populations by electrophoretic polymorphism of five presumably neutral loci. The results indicated that the gene flow between populations existed and the number of effective migrants (Nm) was related to collection geography (Nm from 1.67 to 40.07). In contrast with lower genetic differentiation between two nearby populations (between GZ and ZS, ZZ and SQ) and higher genetic differentiation between two distant populations (between GZ and ZZ), there was a significant and inconsistent difference in the distribution of resistance alleles, A2‐B2 when explained only with active migration. This divergent situation could be straightened out when considering passive migration (such as railway transport) which increased the spread of A2‐B2 along the railway, i.e., in GZ and ZZ. The resistance alleles, A2‐B2, dispersing to around areas by active migration suffered from the limitation of gene flow and the speed of invasion.     

杭州地区尖音库蚊复合组的抗药性动态

用生物测定和淀粉电泳技术对采自杭州市和上海市的尖音库蚊复合组(Culex pipienscomplex)蚊虫的抗性水平及与抗性有关的酯酶进行了研究。抗性水平的测定结果表明:与S-LAB敏感系相比,杭州市种群对DDVP、对硫磷、毒死蜱、邻仲丁基苯基甲基氨基甲酸酯和残杀威的抗性分别是S-LAB敏感品系的3.9,7.6,1.6,1.6,2.5倍。利用淀粉凝胶电泳技术分析了野生种群中抗性羧酸酯酶(EST)等位酶的基因表型及其频率。4个种群中都存在着世界范围内广泛分布的过量产生的非特异性酯酶Estβ1和Estα2/β2,上海种群主要以高活性的酯酶Estβ11为主(98.3%),除了这些基因以外,2004年杭州市下城区又出现了1种新的酯酶基因(50%)。     

French mosquito populations invaded by A2-B2 esterases causing insecticide resistance

In the mosquito Culex pipiens L., the two associated esterases A2 and B2 are responsible for resistance to organophosphorus (OP) insecticides in many countries of Africa, Asia and North America. We report here their presence and geographic spread in French populations based on the analysis of 168 samples collected from 1984 to 1990. First detected in 1986 in one sample from southern France, these esterases were progressively found in new geographic locations, so that in 1990 their distribution covered at least four contiguous French regions. RFLP analysis of the amplified B2 gene indicates that A2-B2 arrived in France most likely through migration. This genetic invasion is discussed in the light of the recent occurrence of A2-B2 in the mosquito genome, and of the consequences of this new resistance factor in natural populations already possessing other insecticide resistance genes.     

抑制剂存在下不同种群烟粉虱乙酰胆碱酯酶残余活性频率分布及其与抗药性的关系

为了探讨烟粉虱Bemisia tabaci不同种群个体乙酰胆碱酯酶敏感性差异及其与抗药性的关系, 我们选用室内饲养的烟粉虱SUD S敏感品系和6个田间抗性种群, 采用酶标板酶动力学法测定了各品系 (种群）乙酰胆碱酯酶对抑制剂的敏感性反应以及抑制剂存在时各抗性种群个体乙酰胆碱酯酶残余活性频率分布。结果表明: 在抑制剂浓度为300 μmol/L时, 敏感品系乙酰胆碱酯酶的活性基本上被完全抑制, 可以明显地区分敏感品系与田间抗性种群。在抑制剂浓度为2 000 μmol/L时, 各抗性种群个体乙酰胆碱酯酶残余活性频率分布差异明显, 其中ZZ-R种群和FZ-R种群的乙酰胆碱酯酶残余活性频率分布相似, 大部分个体的乙酰胆碱酯酶残余活性分布在1.00~1.80 mOD/min之间; SM-R种群和ND-R种群的乙酰胆碱酯酶残余活性频率分布也相似, 大部分个体的乙酰胆碱酯酶残余活性分布在0.40~1.00 mOD/min之间; LY-R和NP-R种群大部分个体的乙酰胆碱酯酶残余活性分别分布在1.00~1.60 mOD/min和0.80~1.20 mOD/min之间。各抗性种群乙酰胆碱酯酶高残余活性 (大于1.00 mOD/min）个体频率与对敌敌畏的抗性水平之间具有明显相关性, 相关系数为0.86 (P<0.05）。考虑到乙酰胆碱酯酶对抑制剂作用不敏感是一些昆虫对有机磷和氨基甲酸酯类杀虫剂抗性的重要机制之一, 建议可以将乙酰胆碱酯酶对敌敌畏的敏感性作为烟粉虱抗药性生化检测的一个参考指标。     

Insecticide use and organophosphate resistance in the coffee leaf miner Leucoptera coffeella (Lepidoptera: Lyonetiidae)

Increasing rates of insecticide use against the coffee leaf minerLeucoptera coffeella(Guérin-Méneville) and field reports on insecticide resistance led to an investigation of the possible occurrence of resistance of this species to some of the oldest insecticides used against it in Brazil: chlorpyrifos, disulfoton, ethion and methyl parathion. Insect populations were collected from ten sites in the state of Minas Gerais, Brazil and these populations were subjected to discriminating concentrations established from insecticide LC99s estimated for a susceptible standard population. Eight of the field-collected populations showed resistance to disulfoton, five showed resistance to ethion, four showed resistance to methyl parathion, and one showed resistance to chlorpyrifos. The frequency of resistant individuals in each population ranged from 10 to 93% for disulfoton, 53 to 75% for ethion, 23 to 76% for methyl parathion, and the frequency of resistant individuals in the chlorpyrifos resistant population was 35%. A higher frequency of individuals resistant to chlorpyrifos, disulfoton and ethion was associated with greater use of insecticides, especially other organophosphates. This finding suggests that cross-selection, mainly between organophosphates, played a major role in the evolution of insecticide resistance in Brazilian populations of L. coffeella. Results from insecticide bioassays with synergists (diethyl maleate, piperonyl butoxide and triphenyl phosphate) suggested that cytochrome P450-dependent monooxygenases may play a major role in resistance with minor involvement of esterases and glutathione S-transferases.     

淡色库蚊酯酶等位基因及其在自然种群中的频率分布

酯酶基因扩增所产生的酯酶活性升高是库蚊Culex pipiens对有机磷杀虫剂抗性的主要机理之一。采用分子杂交技术和限制性酶切片段长度多态性(RFLP)分析,已鉴定出多种酯酶等位基因类型。该文通过酯酶基因特异性片段的PCR扩增及扩增片段的酶切片段分析,对淡色库蚊Culex pipiens pallens四种有机磷抗性品系的酯酶等位基因进行分型,并测定分析自然种群中不同酶型的频率分布。研究结果表明：PCR分型方法具有快速、准确的特点。不同的有机磷杀虫剂对酯酶等位基因具有明显的选择作用。双硫磷品系为B₁型;毒死蜱和敌百虫品系为B₂型;马拉硫磷品系为B₁型和B₁/B₂杂合型。不同地区采集的种群表现出不同的酶型频率分布。该文就杀虫剂对酯酶等位基因选择作用及自然种群的酶型频率分布进行了讨论。     

广东省三市致倦库蚊种群的抗性水平、非特异性酯酶分布频率及遗传分化

致卷库蚊(Culex pipiens quinquefasciatus)样本于2001年5月采自广州、佛山和中山。利用生物测定和淀粉凝胶电泳检测其对有机磷和氨基甲酸酯类杀虫剂的抗性水平和抗性相关酯酶的分布频率。与北京敏感品系相比,3个种群对敌敌畏、对硫磷、仲丁威的抗性水平分别至少为21、8和5倍;以连锁形式存在的A8／B8和A9／B9是3种群主要的高活性酯酶,但A2／B2和B1有地区差异。由于种群间的基因流动,这些差异行将消失。     

Effects of chlorpyrifos on enzymatic systems of Cydia pomonella (Lepidoptera: Tortricidae) adults

The control program of codling moth (Cydia pomonella L.) in the Río Negro and Neuquén Valley is intended to neonate larvae. However, adults may be subjected to sublethal pesticide concentrations generating stress which might enhance both mutation rates and activity of the detoxification system. This study assessed the exposure effects of chlorpyrifos on target enzyme and, both detoxifying and antioxidant systems of surviving adults from both a laboratory susceptible strain (LSS) and a field population (FP). The results showed that the FP was as susceptible to chlorpyrifos as the LSS and, both exhibited a similar chlorpyrifos‐inhibitory concentration 50 (IC₅₀) of acetylcholinesterase (AChE). The FP displayed higher carboxylesterase (CarE) and 7‐ethoxycoumarine O‐deethylase (ECOD) activities than LSS. Both LSS and FP showed an increase on CarE activity after the exposure to low‐chlorpyrifos concentrations, followed by enzyme inhibition at higher concentrations. There were no significant differences neither in the activities of glutathione S‐transferases (GST), catalase (CAT) and superoxide dismutase (SOD) nor in the reduced glutathione (GSH) content between LSS and FP. Moreover, these enzymes were unaffected by chlorpyrifos. In conclusion, control adults from the FP exhibited higher CarE and ECOD activities than control adults from the LSS. AChE and CarE activities were the most affected by chlorpyrifos. Control strategies used for C. pomonella, such as rotations of insecticides with different modes of action, will probably delay the evolution of insecticide resistance in FPs from the study area.     

Organophosphate and pyrethroid resistances in the tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae) from Iran

The tomato leafminer, Tuta absoluta (Meyrich) (Lepidoptera: Gelechiidae), is a serious pest of tomato crops worldwide. The intensive use of chemical pesticides to control it has led to the selection of resistant populations. This study investigated the resistance of T. absoluta populations to pyrethroid and the organophosphate insecticides from ten regions of Iran. The resistance ratios at LC₅₀ for chlorpyrifos and diazinon varied among populations from 4.3 to 12 and from 1.4 to 9.0, respectively. The resistance ratios of the pyrethroids cypermethrin, deltamethrin and permethrin varied from 1.3 to 3.7, 2.7 to 13 and 1.2 to 4.3, respectively. Inclusion of synergists in toxicological bioassays and the variation observed in the activity of esterases, glutathione S‐transferase and cytochrome P450‐dependent monooxygenase suggest the existence of metabolically based resistance. Esterase and P450 biochemical assays were positively correlated with deltamethrin, and cypermethrin tolerance and diazinon tolerance correlated with esterase activity. The genes encoding the organophosphate and pyrethroid target sites acetylcholinesterase (ace1) and sodium channel (kdr) were partly sequenced. The genotyping revealed mutations in high frequencies in all populations leading to an A201S substitution in ace1 and three substitutions in the sodium channel gene L1014F, M918T, T929I. In summary, our results indicate the presence of organophosphate and pyrethroid resistance in Iranian T. absoluta populations with involvement of both detoxification enzymes and target site alterations. Most likely the populations of T. absoluta imported to Iran were resistant upon arrival.     

The involvement of acetylcholinesterase in resistance of the California red scale shape Aonidiella aurantii to organophosphorus pesticides

Laboratory toxicity bioassays using chlorpyrifos (Dursban) confirmed the notion that development of resistance is responsible for widespread failures to control the California red scale, Aonidiella aurantii (Mask.) by applying organophosphorus (OP) compounds in citrus groves in Israel. Higher Vmax values of acetylcholinesterase (AChE) activity (9–13 fold) were measured in resistant strains collected from the field as compared to a susceptible line. No differences were found with respect to Km values using acetylthiocholine iodide as a substrate, or degree of inhibition (expressed by IC₅₀ values) by the OP compounds chlorpyrifos-oxon and paraoxon and the carbamate pirimicarb. We suggest that resistance of the California red scale is caused by excess of AChE molecules able to bind and thus scavenge inhibitory OP compounds. This scavenging mechanism related to AChE may be similar in other insect species where elevated levels of detoxifying esterases were implicated in conferring OP resistance.     

Mechanisms of organophosphate resistance in a field population of oriental migratory locust, Locusta migratoria manilensis (Meyen)

The susceptibilities to three organophosphate (OP) insecticides (malathion, chlorpyrifos, and phoxim), responses to three metabolic synergists [triphenyl phosphate (TPP), piperonyl butoxide (PBO), and diethyl maleate (DEM)], activities of major detoxification enzymes [general esterases (ESTs), glutathione S-transferases (GSTs), and cytochrome P450 monooxygenases (P450s)], and sensitivity of the target enzyme acetylcholinesterase (AChE) were compared between a laboratory-susceptible strain (LS) and a field-resistant population (FR) of the oriental migratory locust, Locusta migratoria manilensis (Meyen). The FR was significantly resistant to malathion (57.5-fold), but marginally resistant to chlorpyrifos (5.4) and phoxim (2.9). The malathion resistance of the FR was significantly diminished by TPP (synergism ratio: 16.2) and DEM (3.3), but was unchanged by PBO. In contrast, none of these synergists significantly affected the toxicity of malathion in the LS. Biochemical studies indicated that EST and GST activities in the FR were 2.1- to 3.2-fold and 1.2- to 2.0-fold, respectively, higher than those in the LS, but there was no significant difference in P450 activity between the LS and FR. Furthermore, AChE from the FR showed 4.0-fold higher activity but was 3.2-, 2.2-, and 1.1-fold less sensitive to inhibition by malaoxon, chlorpyrifos-oxon, and phoxim, respectively, than that from the LS. All these results clearly indicated that the observed malathion resistance in the FR was conferred by multiple mechanisms, including increased detoxification by ESTs and GSTs, and increased activity and reduced sensitivity of AChE to OP inhibition.     

Toxicity,inheritance and biochemistry of clofentezine resistance in Tetranychus urticae

Abstract This study evaluates the toxicological and biochemical response of two‐spotted spider mites to clofentezine selection pressure. The mortality rate of Tetranychus urticae in adult females depends on increased clofentezine concentration and clofentezine was found to be effective against females. The resistance rate of the CUM strain selected 12 times once per generation with clofentezine was increased from 1.28‐ to 105.27‐fold. The interaction of some synergists with clofentezine was analyzed in the clofentezine‐resistant CLOF 12 strain. Synergists had no effect on clofentezine toxicity. The clofentezine‐resistant CLOF 12 strain showed resistance against chlorpyrifos, abamectin, propargite, fenpyroximate and amitraz. The modes of inheritance of resistance to clofentezine were found to be incompletely dominant and not sex‐linked. Esterase enzyme activity was detected both by gel electrophoresis and microplate reader methods, while glutathione S‐transferase (GST) and monooxygenase (P450) activity were detected only by the microplate reader method. During the selection period the esterase, the GST and the P450 enzymes activities were raised from 7.69, 7.09 and 0.003 3 to 18.40, 13.11 and 0.003 7 milli‐optical density/min/mg proteins, respectively. An increase was observed in the band intensity of esterases and esterase enzymes may play a role in clofentezine resistance in T. urticae.     

Trade‐off between thermal tolerance and insecticide resistance in Plutella xylostella

Fitness costs associated with resistance to insecticides have been well documented, usually at normal temperature conditions, in many insect species. In this study, using chlorpyrifos‐resistant homozygote (R_R) and chlorpyrifos‐susceptible homozygote (S_S) of resistance ace1 allele of Plutella xylostella (DBM), we confirmed firstly that high temperature experience in pupal stage influenced phenotype of wing venation in insecticide‐resistant and insecticide‐susceptible Plutella xylostella, and S_S DBM showed significantly higher thermal tolerance and lower damages of wing veins under heat stress than R_R DBM. As compared to S_S DBM, R_R DBM displayed significantly lower AChE sensitivity to chlorpyrifos, higher basal GSTs activity and P450 production at 25°C, but higher inhibitions on the enzyme activities and P450 production as well as reduced resistance to chlorpyrifos under heat stress. Furthermore, R_R DBM displayed significantly higher basal expressions of hsp69s, hsp72s, hsp20, hsp90, Apaf‐1, and caspase‐7 at 25°C, but lower induced expressions of hsps and higher induced expressions of Apaf‐1, caspase‐9, and caspase‐7 under heat stress. These results suggest that fitness costs of chlorpyrifos resistance in DBM may partly attribute to excess consumption of energy caused by over production of detoxification enzymes and hsps when the proteins are less demanded at conducive environments but reduced expressions when they are highly demanded by the insects to combat environmental stresses, or to excess expressions of apoptotic genes under heat stress, which results in higher apoptosis. The evolutionary and ecological implications of these findings at global warming are discussed.     

Monitoring and mechanisms of organophosphate resistance in San Jose scale,Diaspidiotus perniciosus (Hemiptera: Diaspididae)

San Jose scale, Diaspidiotus perniciosus (Comstock), is a serious pest in Chilean apple tree orchards, and a number of organophosphate insecticides were used to control them for decades. Recently, control failures with these insecticides were reported and linked to insecticide resistance development. In this study, 40 San Jose scale field populations were collected and their susceptibility to two commonly used organophosphate insecticides, that is chlorpyrifos and methidathion, was assessed. The obtained bioassay data suggest moderate levels of resistance to both insecticides when compared to a reference susceptible strain. The highest resistance ratio (RR) detected for chlorpyrifos and methidathion was 31‐fold and 11‐fold, respectively. The bioassay results suggest the occurrence of a significant cross‐resistance between both compounds. Biochemical measurements revealed a role for esterases in conferring resistance to organophosphates, but not modified acetylcholinesterase. The spatial spread and extend of insecticide resistance were also evaluated. Our result shows that no autocorrelation can be assumed, and then, insecticide resistance is caused by random factors.     

Insecticide resistance of Culex pipiens (L.) populations (Diptera: Culicidae) from Riyadh city,Saudi Arabia: Status and overcome

Three field populations of Cx. pipiens (L.) mosquitoes were collected from three different localities in Riyadh city. They were tested for developing resistance against commonly used insecticides to control mosquitoes in Riyadh. Two populations from Wadi Namar (WN1 and WN2) were highly resistant to deltamethrin (187.1- and 161.4-folds respectively). The field population from AL-Wadi district (AL-W) showed low resistance to lambda-cyhalothrin (3.8-folds) and moderate resistance to beta-cyfluthrin and bifenthrin (14- and 38.4-folds respectively). No resistance to fenitrothion was observed in WN1 population. Fenitrothion concentrations required to inhibit 50% of Acetylcholinesterase (AChE) activity in both WN1 population and the laboratory susceptible strain (S-LAB) were 0.073 and 0.078 ppm respectively. Piperonyl butoxide suppressed resistance to pyrethroid insecticides (>90%) in field populations indicating that oxidases and/or esterases play an important role in the reduction of pyrethroids toxicity. These results should be considered in the current mosquitoes control programs in Riyadh.     

不同地理种群尖音库蚊复组抗性动态和遗传多样性

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 pipiens complex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。     

INSECTICIDE RESISTANCE IN THE GROUND SPIDER,Pardosa sumatrana (THORELL, 1890; ARANEAE: LYCOSIDAE)

Elevated levels of insecticides detoxifying enzymes, such as esterases, glutathione S‐transferases (GSTs), and cytochrome P‐450 monooxygenases, act in the resistance mechanisms in insects. In the present study, levels of these enzymes in the insecticide‐resistant ground spider Pardosa sumatrana (Thorell, 1890) were compared with a susceptible population (control) of the same species. Standard protocols were used for biochemical estimation of enzymes. The results showed significantly higher levels of nonspecific esterases and monooxygenases in resistant spiders compared to controls. The activity of GSTs was lower in the resistant spiders. Elevated levels of nonspecific esterases and monooxygenases suggest their role in metabolic resistance in P. sumatrana. The reduced levels of total protein contents revealed its possible consumption to meet energy demands.