The ambrosia beetles are farming insects that feed mainly on their cultivated fungi, which in some occasions are pathogens from forest and fruit trees. We used a culture-independent approach based on 16S and 18S rRNA gene metabarcoding analysis to investigate the diversity and composition of the bacterial and fungal communities associated with five ambrosia beetle species: four species native to America (Monarthrum dimidiatum, Dryocoetoides capucinus, Euwallacea discretus, Corthylus consimilis) and an introduced species (Xylosandrus morigerus). For the bacterial community, the beetle species hosted a broad diversity with 1,579 amplicon sequence variants (ASVs) and 66 genera, while for the fungal community they hosted 288 ASVs and 39 genera. Some microbial groups dominated the community within a host species or a body part (Wolbachia in the head-thorax of E. discretus; Ambrosiella in the head-thorax and abdomen of X. morigerus). The taxonomic composition and structure of the microbial communities appeared to differ between beetle species; this was supported by beta-diversity analysis, which indicated that bacterial and fungal communities were clustered mainly by host species. This study characterizes for the first time the microbial communities associated with unexplored ambrosia beetle species, as well as the factors that affect the composition and taxonomic diversity per se, contributing to the knowledge of the ambrosia beetle system.

豚草甲虫是一种农业昆虫，主要以其栽培的真菌为食，在某些情况下，这些真菌是来自森林和果树的病原体。我们使用基于 16S 和 18S rRNA 基因元条形码分析的独立培养方法来研究与五种豚草甲虫物种相关的细菌和真菌群落的多样性和组成：四种原产于美洲的物种（Monarthrum dimidiatum、Dryocoetoides capucinus、Euwallacea Discretus、Corthylus consimilis）和引进物种（Xylosandrus morigerus）。对于细菌群落来说，甲虫物种拥有广泛的多样性，有 1,579 个扩增子序列变体 (ASV) 和 66 个属，而对于真菌群落来说，它们拥有 288 个 ASV 和 39 个属。一些微生物群在宿主物种或身体部位内占主导地位（Wolbachia存在于E.discretus的头胸部；Ambrosiella存在于X.morigerus的头胸部和腹部）。甲虫物种之间微生物群落的分类组成和结构似乎有所不同；β-多样性分析支持了这一点，该分析表明细菌和真菌群落主要按宿主物种聚集。这项研究首次描述了与未探索的豚草甲虫物种相关的微生物群落，以及影响其组成和分类多样性本身的因素，有助于了解豚草甲虫系统。