Abstract: Objective To evaluate the level of resistance of Aedes albopictus to pyrethroid insecticides in Guiyang,China,and identify mutations in the knockdown resistance gene, so as to provide a scientific basis for the control of Ae. albopictus in the region.Methods From July to August 2022,the larvae of Ae. albopictus were captured at different locations of Guiyang and then reared to F1-F2 generations in the laboratory. The resistance to pyrethroid insecticides was determined by using the dipping method for larvae and the World Health Organization tube method for adult mosquitoes. The genomic DNA of individual adult Ae. albopictus mosquito was extracted for PCR amplification and sequencing to detect knockdown resistance gene mutations. The Chi-square test was used to analyze the frequency differences of mutant genes between groups.Results The median lethal concentrations of deltamethrin, permethrin, and beta-cypermethrin against Ae. albopictus larvae in Guiyang were 0.559, 0.021, and 0.012 mg/L, respectively;and the resistance ratios were 433.33, 46.67, and 16.44, respectively. The mortality rates of adult Ae. albopictus mosquitoes exposed to 0.03% deltamethrin, 0.4% permethrin, and 0.08% beta-cypermethrin were all <80%. No mutations were detected at the 1016, 1532, and 1534 loci in the sensitive population of Ae. albopictus. Knockdown resistance gene mutations were found at all the three loci in the natural population of Ae. albopictus. There were two alleles at 1016 locus, which were wild-type GTA (V) (76.35%) and mutant GGA (G) (23.65%), with no statistically significant differences in frequency of mutant genes between the sensitive and resistant phenotypes (χ²=1.810, P=0.178); There were three genotypes at 1016 locus: wild-type homozygous V/V (58.78%), wild/mutant heterozygous V/G (35.14%),and mutant homozygous G/G (6.08%). There were two alleles at 1532 locus, which were wild-type ATC (I) (99.83%) and mutant ACC (T) (0.17%),with two genotypes of wild-type homozygous I/I (99.66%) and wild/mutant heterozygous I/T (0.34%). There were two alleles at 1534 locus, namely wild-type TTC (F) (48.48%) and mutant TCC (S) (51.52%),with no statistically significant difference in frequency of mutant genes between the sensitive and resistant phenotypes (χ²=0.603, P=0.437); There were three genotypes at 1534 locus: wild-type homozygous F/F (8.11%), wild/mutant heterozygous F/S (80.74%),and mutant heterozygous S/S (11.15%).Conclusions Larval and adult Ae. albopictus mosquitoes in Guiyang have developed medium-to-high resistance to the three pyrethroid insecticides and mutations in the knockdown resistance gene,but with no significant association between the mutations and the resistant phenotypes. The level of resistance in the region should be continuously monitored to guide the scientific and rational use of insecticides to effectively control mosquitoes and delay the evolution of insecticide resistance.

Key words: Aedes albopictus, Insecticide resistance, Knockdown resistance gene, Resistance phenotype

摘要： 目的了解贵阳市白纹伊蚊对拟除虫菊酯类杀虫剂的抗性程度并检测击倒抗性基因突变,为该地区白纹伊蚊防治提供科学依据。方法2022年7－8月在贵阳市不同方位采集白纹伊蚊幼虫,带回实验室饲养至F1～F2代,采用幼虫浸渍法和成蚊接触筒法测定其对拟除虫菊酯类杀虫剂的抗药性；单只提取白纹伊蚊成蚊基因组DNA,采用普通PCR扩增后直接测序的方法分析击倒抗性基因突变。χ²检验用于分析各组间突变基因频率差异。结果贵阳市白纹伊蚊幼虫对溴氰菊酯、氯菊酯和高效氯氰菊酯的半数致死浓度（LC₅₀）分别为0.559、0.021和0.012 mg/L,抗性倍数分别为433.33、46.67和16.44倍；0.03%溴氰菊酯、0.4%氯菊酯和0.08%高效氯氰菊酯处理后白纹伊蚊成蚊的死亡率均<80.00%；敏感品系白纹伊蚊在1016、1532和1534基因位点均未检测到突变,自然种群白纹伊蚊在3个位点均检测到击倒抗性基因突变。1016位点有2种等位基因,即野生型GTA（V）（76.35%）和突变型GGA（G）（23.65%）,其敏感表型与抗性表型突变基因频率差异无统计学意义（χ²=1.810,P=0.178）；有3种基因型,即野生型纯合子V/V（58.78%）、野生/突变型杂合子V/G（35.14%）和突变型纯合子G/G（6.08%）。1532位点有2种等位基因,即野生型ATC（I）（99.83%）和突变型ACC（T）（0.17%）；有2种基因型,即野生型纯合子I/I（99.66%）和野生/突变型杂合子I/T（0.34%）。1534位点有2种等位基因,即野生型TTC（F）（48.48%）和突变型TCC（S）（51.52%）,其敏感表型与抗性表型突变基因频率差异无统计学意义（χ²=0.603,P=0.437）；有3种基因型,即野生型纯合子F/F（8.11%）、野生/突变型杂合子F/S（80.74%）和突变型纯合子S/S（11.15%）。结论贵阳市白纹伊蚊幼虫和成蚊对3种拟除虫菊酯类杀虫剂均已产生中高抗性,并发生击倒抗性基因突变,但未发现其基因突变与抗性表型有明显关联；可持续监测该地区白纹伊蚊抗药性水平,指导杀虫剂科学合理使用,以有效防治蚊虫和延缓杀虫剂抗性产生和发展。

关键词: 白纹伊蚊, 抗药性, 击倒抗性基因, 抗性表型