Lepidoptera (butterflies and moths) are diverse and ecologically important, yet we know little about how they interact with microbes as adults. Due to metamorphosis, the form and function of their adult-stage microbiomes might be very different from those of microbiomes in the larval stage (caterpillars). We studied adult-stage microbiomes of Heliconius and closely related passion-vine butterflies (Heliconiini), which are an important model system in evolutionary biology. To characterize the structure and dynamics of heliconiine microbiomes, we used field collections of wild butterflies, 16S rRNA gene sequencing, quantitative PCR, and shotgun metagenomics. We found that Heliconius butterflies harbor simple and abundant bacterial communities that are moderately consistent among conspecific individuals and over time. Heliconiine microbiomes also exhibited a strong signal of the host phylogeny, with a major distinction between Heliconius and other butterflies. These patterns were largely driven by differing relative abundances of bacterial phylotypes shared among host species and genera, as opposed to the presence or absence of host-specific phylotypes. We suggest that the phylogenetic structure in heliconiine microbiomes arises from conserved host traits that differentially filter microbes from the environment. While the relative importance of different traits remains unclear, our data indicate that pollen feeding (unique to Heliconius) is not a primary driver. Using shotgun metagenomics, we also discovered trypanosomatids and microsporidia to be prevalent in butterfly guts, raising the possibility of antagonistic interactions between eukaryotic parasites and colocalized gut bacteria. Our discovery of characteristic and phylogenetically structured microbiomes provides a foundation for tests of adult-stage microbiome function, a poorly understood aspect of lepidopteran biology.

中文翻译：

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Heliconius蝴蝶寄养特征和系统发育的成年微生物群落。

鳞翅目（蝴蝶和飞蛾）是多种多样的，并且在生态上很重要，但是我们对它们成年后与微生物的相互作用知之甚少。由于变态，它们成年阶段微生物群的形式和功能可能与幼虫阶段（类目）的微生物群的形式和功能有很大不同。我们研究了Heliconius和密切相关的西番莲蝴蝶（Heliconiini）的成年期微生物群落，这是进化生物学中的重要模型系统。为了表征螺旋藻微生物群的结构和动力学，我们使用了野蝴蝶的野外采集，16S rRNA基因测序，定量PCR和shot弹枪宏基因组学。我们发现Heliconius蝴蝶带有简单而丰富的细菌群落，在特定个体之间并随着时间的流逝具有中等程度的一致性。Helicooniine微生物群也表现出宿主系统发育的强烈信号，Heliconius和其他蝴蝶之间有很大的区别。这些模式很大程度上是由宿主物种和属之间共有的不同细菌菌种相对相对丰度所驱动的，这与是否存在宿主特异性菌种不同。我们建议，螺旋藻微生物群的系统发育结构是由保守的宿主特征产生的，该宿主特征有区别地从环境中过滤掉微生物。虽然尚不清楚不同性状的相对重要性，但我们的数据表明，花粉摄食（对Heliconius是唯一的））不是主要驱动程序。使用散弹枪宏基因组学，我们还发现锥虫和微孢子虫在蝶形肠道中很普遍，这增加了真核生物寄生虫和共居肠道细菌之间拮抗相互作用的可能性。我们对特征性和系统发育的微生物组的发现为成人阶段微生物组功能的测试奠定了基础，而成人阶段微生物组功能是对鳞翅目生物学的一个鲜为人知的方面。