The spruce bark beetle (Ips typographus L.) is a destructive pest of Eurasian spruce forests. Although the gut bacteria of this insect are considered to play important roles in its lifecycle, the relationship between I. typographus and its gut bacterial community is poorly characterized. In this study, 16S rRNA gene sequencing was used to determine gut bacterial community composition across successive I. typographus life stages. Responses of the gut bacteria to α-pinene enantiomers were also explored. Ips typographus gut bacterial populations were dominated by the phyla Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, and the relative abundance of these phyla varied across different developmental stages of the beetle. Bacterial species diversity and richness indices increased with developmental stage progression. Relative abundances of the dominant genera, Erwinia (Enterobacteriales: Enterobacteriaceae), Pseudoxanthomonas (Xanthomonadales: Xanthomonadaceae), Serratia (Enterobacteriales: Enterobacteriaceae), and Romboutsia (Clostridiales: Peptostreptococcaceae), also varied across successive I. typographus life stages. Large disparities in the gut bacterial community of male adults were observed when the beetles were treated with S-(-)-α-pinene and R-(+)-α-pinene. The relative abundances of Lactococcus (Lactobacillales: Streptococcaceae) and Lelliottia (Enterobacteriales: Enterobacteriaceae) increased drastically with R-(+)-α-pinene and S-(-)-α-pinene treatment, respectively. This indicated a distinct enantiomer-specific effect of α-pinene on the I. typographus gut bacteria. This study demonstrated the plasticity of gut bacteria during I. typographus development, when α-pinene host monoterpenes are encountered. This study provides new insights into the relationship between 'I. typographus-gut bacteria' symbionts and host trees.

中文翻译：

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对映异构体特异性α-蒎烯诱导Ips Typgraphus（鞘翅目： Curculionidae）肠道细菌群落的差异

云杉树皮甲虫（Ips Typgraphus L.）是欧亚云杉林的一种破坏性害虫。尽管这种昆虫的肠道细菌被认为在其生命周期中发挥着重要作用，但 I. Typgraphus 与其肠道细菌群落之间的关系尚未得到很好的表征。在这项研究中，16S rRNA 基因测序用于确定连续的印刷 I.印刷生命阶段的肠道细菌群落组成。还探索了肠道细菌对 α-蒎烯对映体的反应。Ips Typgraphus 肠道细菌种群主要由变形菌门、厚壁菌门、拟杆菌门和放线菌门主导，这些门的相对丰度在甲虫的不同发育阶段有所不同。细菌物种多样性和丰富度指数随着发育阶段的进展而增加。优势属的相对丰度，欧文氏菌（肠杆菌目：肠杆菌科）、假单胞菌属（黄单胞菌目：黄单胞菌科）、沙雷氏菌（肠杆菌目：肠杆菌科）和罗氏菌属（梭菌目：消化链球菌科的连续生活阶段）。当甲虫用 S-(-)-α-蒎烯和 R-(+)-α-蒎烯处理时，观察到雄性成虫肠道细菌群落的巨大差异。乳球菌（Lactobacillales：链球菌科）和 Lelliottia（肠杆菌目：肠杆菌科）的相对丰度分别随着 R-(+)-α-蒎烯和 S-(-)-α-蒎烯处理而急剧增加。这表明 α-蒎烯对 I.typgraphus 肠道细菌具有明显的对映异构体特异性作用。这项研究证明了肠道细菌在 I 期间的可塑性。当遇到α-蒎烯宿主单萜时，印刷术的发展。这项研究为“I”之间的关系提供了新的见解。排印-肠道细菌的共生体和寄主树。