思茅松毛虫关键龄期幼虫肠道可培养细菌多样性分析

【目的】对思茅松毛虫（Dendrolimu kikuchii）关键龄期幼虫肠道可培养细菌多样性进行研究，探索其肠道细菌资源及多样性，为深入研究昆虫肠道微生物功能及思茅松毛虫的种群管理打下基础。【方法】采用传统微生物分离培养法对采集自云南省安宁市草铺镇林区的思茅松毛虫1、4和7龄幼虫进行肠道细菌分离纯化，对分离获得的细菌进行16S rDNA序列同源性分析，初步判定其分类学地位并进行多样性分析。【结果】从思茅松毛虫幼虫肠道中共分离得到291株细菌，隶属于15属31种，其中1龄幼虫肠道98株细菌隶属于9属13种，4龄幼虫肠道102株细菌隶属于6属12种，7龄幼虫肠道91株细菌隶属于6属9种。在31个细菌种中，芽孢杆菌属（Bacillus）最多，共有9个种，占总种数的29.03%，其次是肠杆菌属（Enterobacter）和葡萄球菌属（Staphylococcus）各有4个种，分别占总种数的12.90%。13个1龄幼虫肠道细菌种中，葡萄球菌属、肠杆菌属和芽孢杆菌属的相对分离率分别为27.54%、21.43%和21.43%，高于其他菌属的平均分离率（5.31%）；12个4龄幼虫肠道细菌种中，芽孢杆菌属的相对分离率为72.53%，高于其他菌属的平均分离率（5.49%）；9个7龄幼虫肠道细菌种中，克雷伯氏菌属（Klebsiella）和肠杆菌属的相对分离率分别为43.96%和18.68%，高于其他菌属的平均分离率（9.34%）。思茅松毛虫1龄幼虫肠道细菌的优势度指数、丰富度指数和Shannon-Weiner指数均最大，分别为0.9032、2.6172和2.4310，7龄幼虫肠道细菌的均匀度指数最大，为0.9634。【结论】思茅松毛虫1、4和7龄幼虫肠道可培养细菌群落组成和结构丰富，具有丰富的细菌资源。

Diversity of cultivable bacteria in intestine from key instar larvae of Dendrolimus kikuchii

【Objective】To study the diversity of culturable bacteria in the intestines of critical instar larvae of Dendrolimu kikuchii, and to explore the resources and diversity of intestinal bacteria, so as to lay a foundation for further research on the function of insect intestinal microorganisms and population management of D.kikuchii.【Method】Traditional methods of microorganism isolation, pure culture and identification were used to isolate and purify the intestinal bacteria from the 1st, 4th, and 7th instar larvae collected from the forest area of Caopu Town, Anning City, Yunnan Province.The 16S rDNA sequence homology analysis of the isolated bacteria was conducted to preliminarily determine their taxonomic status and conduct diversity analysis.【Result】A total of 291 strains of bacteria were isolated from the intestines of D.kikuchii larvae, belonging to 31 species of 15 genera.Among them, 98 strains of the intestines of the 1st instar larvae belonged to 13 species of 9 genera, 102 strains of the 4th instar larvae belonged to 12 species of 6 genera, and 91 strains of the 7th instar larvae belonged to 9 species of 6 genera.Among the 31 bacterial species, Bacillus was the most, with 9 species, accounting for 29.03%, followed by Enterobacter and Staphylococcus with each 4 species, accounting for 12.90% of the total species respectively.Among the thirteen 1st instar larvae, the relative isolation rates of Staphylococcus, Enterobacteria and Bacillus were 27.54%, 21.43% and 21.43%, respectively, which were higher than the average isolation rates of other bacteria(5.31%).Among the twelve 4th instar larvae, the relative isolation rate of Bacillus was 72.53%, higher than the average isolation rate of other genera(5.49%).Among the nine 7th instar larvae, the relative isolation rates of Klebsiella and Enterobacteria were 43.96% and 18.68%, respectively, which were higher than the average isolation rates of other bacteria(9.34%).The dominant index, richness index and Shannon-Weiner index of intestinal bacteria of the 1st instar larvae were the highest, which were 0.9032, 2.6172 and 2.4310, respectively.The evenness index of intestinal bacteria of the 7th instar larvae was the highest, which was 0.9634.【Conclusion】The composition and structure of culturable bacterial communities of the 1st, 4th and 7th instar larvae in the intestines of D.kikuchii are rich, and there are abundant bacterial resources.