目的 了解淡色库蚊不同发育阶段肠道菌群的组成与多样性。 方法 取淡色库蚊的Ⅳ龄幼虫、蛹、雌成蚊各20只,分别剖取肠道（每个发育阶段设3个重复）,提取肠道细菌基因组DNA,PCR扩增肠道细菌的16S rRNA高变区序列,采用Illumina NovaSeq6000测序平台进行测序。整理统计测得的序列数目和可操作分类单元（OTU）,采用群落结构柱状图和Veen图分析淡色库蚊不同发育阶段肠道细菌的群落组成与丰度,采用Alpha多样性指数分析微生物群落的丰度和多样性,采用主坐标分析（PCoA）对不同发育阶段肠道细菌群落结构进行差异分析,采用线性判别分析（LEFSe）揭示组间在丰度上有显著差异的物种,采用SPSS 22.0统计学软件对属水平上不同阶段淡色库蚊核心细菌丰度进行单因素方差分析。 结果 淡色库蚊Ⅳ龄幼虫、蛹、雌成蚊的肠道菌群共有1 972个OTU,归属22门45纲112目178科329属。在属水平上,Ⅳ龄幼虫、蛹和雌成蚊肠道细菌分别由230、233和228个属组成,各发育阶段共有的优势属为拟杆菌属[丰度分别为（16.83 + 3.5）%、（26.98 ± 0.94）%、（20.82 ± 2.63）%]、Muribaculaceae[丰度分别为（12.36 ± 1.94）%、（19.98 ± 1.24）%、（14.90 ± 1.52）%]、另枝菌属[丰度分别为（4.13 ± 0.62）%、（7.29 ± 1.28）%、（5.36 ± 1.00）%]和毛螺菌科_NK4A136组[丰度分别为（3.39 ± 0.39）%、（5.77 ± 0.21）%、（3.93 ± 0.40）%]。在OTU水平,Veen图分析结果显示,Ⅳ龄幼虫、蛹、雌成蚊共有的OTU数目为687, 特有的OTU分别为250、284、309。Alpha多样性显示,不同发育阶段淡色库蚊肠道菌群的组成与多样性存在差异（F = 36.83,P < 0.01;F = 28.91,P < 0.01）,蛹的物种丰度和物种多样性最高（6.58 ± 0.04）。PCoA结果显示,肠道菌群分为3组,各阶段分别归为1组;各阶段肠道菌群组成差异有统计学意义（Df = 2, R² = 0.707 44,P < 0.01）。LEFSe结果显示,共17个分类单元在不同发育阶段具有差异;赖氏菌属、拟杆菌属、Muribaculaceae、沃尔巴克氏体属在淡色库蚊不同发育阶段的丰度差异具有统计学意义（F = 48.331、10.826、17.759、95.139,P < 0.01）,赖氏菌属主要存在于Ⅳ龄幼虫阶段（0.887 ± 0.022）,拟杆菌属（0.270 ± 0.009）和Muribaculaceae（0.200 ± 0.012）主要存在于蛹阶段;沃尔巴克氏体属主要存在于雌成蚊阶段（0.172 ± 0.025）。 结论 淡色库蚊不同发育阶段肠道优势菌群主要为拟杆菌属和Muribaculaceae,蛹的物种丰度和物种多样性最高。

Objective To determine the composition and diversity of intestinal microflora of Culex pipiens pallens at different developmental stages. Methods The intestinal tracts of 20 Cx. pipiens pallens Ⅳ-instar larvae, pupae and female mosquitoes were dissected to collect intestinal samples for extraction of genomic DNA of intestinal bacteria, with triplicate for each developmental stage. The 16S rRNA highly variable regions of intestinal bacteria was amplified by PCR and sequenced using the Illumina NovaSeq6000 sequencing platform. The number of sequences and operational taxonomic units (OTU) were compiled and statistically analyzed using structural histogram and Veen diagram to reveal the flora composition and abundance of intestinal bacteria at different developmental stages of Cx. pipiens pallens. The abundance and diversity of microbial flora were analyzed by the Alpha diversity index. Principal coordinate analysis (PCoA) was used to examine the variance in the flora structure at different developmental stages. Linear discriminant analysis (LEFSe) was used to differentiate the species with significant differences in abundance between groups. SPSS 22.0 statistical software was used to conduct one-way ANOVA for genus-based analysis of the core bacterial abundance of Cx. pipiens pallens at different stages. Results The intestinal microbiota of Cx. pipiens pallens larvae, pupae and female mosquitoes were 1 972 OTUs, belonging to 22 phyla, 45 classes, 112 orders, 178 families and 329 genera. At the genus level, the fourth instar larvae, pupae and female mosquitoes were composed of 230, 233 and 228 genera, respectively. The dominant genera were Bacteroides with the abundance of (16.83 ± 3.5) %, (26.98 ± 0.94) % and (20.82 ± 2.63) %, respectively; Muribaculaceae, the abundance was (12.36 ± 1.94) %, (19.98 ± 1.24) %, (14.90 ± 1.52) %, respectively; the abundance of Alistipes was (4.13 ± 0.62)%, (7.29 ± 1.28)%, (5.36 ± 1.00)%, respectively; Lachnospiraceae_NK4A136_group were (3.39 ± 0.39)%, (5.77 ± 0.21) % and (3.93 ± 0.40)%, respectively. At the level of OTU, Veen diagram analysis showed that the number of OTU shared by the fourth instar larvae, pupae and female adult was 687, and the unique OTU was 250, 284 and 309, respectively. Alpha diversity showed that the composition and diversity of Cx. pipiens pallens were different at different developmental stages (F = 36.83, P < 0.01; F = 28.91, P < 0.01), the species abundance and diversity of pupae were the highest (6.58 ± 0.04). The results of PCoA showed that the microflora was presented in three groups, with each stage falling into one group, respectively. There were statistically significant differences in the composition of bacteria among different stages (Df = 2, R² = 0.707 44, P < 0.01). The results of LEFSe showed that 17 taxa were different at developmental stages. There were statistically significant differences in the abundance of Leifsonia, Bacteroides, Muribaculaceae and Wolbachia in different developmental stages of Cx. pipiens pallens (F = 48.331, 10.826, 17.759, 95.139, P < 0.01). Leifsonia mainly existed in the fourth instar larval stage (0.887 ± 0.022), Bacteroidetes (0.270 ± 0.009) and Muribaculaceae (0.200 ± 0.012) mainly existed in the pupa stage. Wolbachia mainly existed in the female mosquito stage (0.172 ± 0.025). Conclusion The dominant intestinal flora of Cx. pipiens pallens at different developmental stages are Bacteroides and Muribaculaceae, and the pupa shows the highest species abundance and species diversity.