Microbiomes can have profound impacts on host biology and evolution, but to date, remain vastly understudied in spiders despite their unique and diverse predatory adaptations. This study evaluates closely related species of spiders and their host-microbe relationships in the context of phylosymbiosis, an eco-evolutionary pattern where the microbial community profile parallels the phylogeny of closely related host species. Using 16S rRNA gene amplicon sequencing, we characterized the microbiomes of five species with known phylogenetic relationships from the family Theridiidae, including multiple closely related widow spiders (L. hesperus, L. mactans, L. geometricus, S. grossa, and P. tepidariorum). We compared whole animal and tissue-specific microbiomes (cephalothorax, fat bodies, venom glands, silk glands, and ovary) in the five species to better understand the relationship between spiders and their microbial symbionts. This showed a strong congruence of the microbiome beta-diversity of the whole spiders, cephalothorax, venom glands, and silk glands when compared to their host phylogeny. Our results support phylosymbiosis in these species and across their specialized tissues. The ovary tissue microbial dendrograms also parallel the widow phylogeny, suggesting vertical transfer of species-specific bacterial symbionts. By cross-validating with RNA sequencing data obtained from the venom glands, silk glands and ovaries of L. hesperus, L. geometricus, S. grossa, and P. tepidariorum we confirmed that several microbial symbionts of interest are viably active in the host. Together these results provide evidence that supports the importance of host-microbe interactions and the significant role microbial communities may play in the evolution and adaptation of their hosts.

中文翻译：

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蜘蛛系统共生：寡妇蜘蛛物种及其组织微生物组的分歧。


微生物组可以对宿主生物学和进化产生深远的影响，但迄今为止，尽管蜘蛛具有独特且多样化的捕食适应能力，但迄今为止，对它们的研究仍然很少。这项研究在系统共生的背景下评估了密切相关的蜘蛛物种及其宿主-微生物关系，系统共生是一种生态进化模式，其中微生物群落概况与密切相关的宿主物种的系统发育平行。利用 16S rRNA 基因扩增子测序，我们对 Theridiidae 科中具有已知系统发育关系的 5 个物种的微生物组进行了表征，包括多种密切相关的寡妇蜘蛛（L. hesperus、L. mactans、L. Geometricus、S.grossa 和 P. tepidariorum） ）。我们比较了五个物种的整个动物和组织特异性微生物组（头胸部、脂肪体、毒腺、丝腺和卵巢），以更好地了解蜘蛛与其微生物共生体之间的关系。这表明，与宿主系统发育相比，整个蜘蛛、头胸部、毒腺和丝腺的微生物组β多样性具有很强的一致性。我们的结果支持这些物种及其专门组织中的系统共生。卵巢组织微生物树状图也与寡妇系统发育平行，表明物种特异性细菌共生体的垂直转移。通过与从 L. hesperus、L. Geometricus、S.grossa 和 P. tepidariorum 的毒腺、丝腺和卵巢获得的 RNA 测序数据进行交叉验证，我们证实了几种感兴趣的微生物共生体在宿主中具有活性。这些结果共同提供了证据，支持宿主-微生物相互作用的重要性以及微生物群落在宿主的进化和适应中可能发挥的重要作用。