Microbial metabolism can shape cues important for animal attraction in service-resource mutualisms. Resources are frequently colonized by microbial communities, but experimental assessment of animal-microbial interactions often focus on microbial monocultures. Such an approach likely fails to predict effects of microbial assemblages, as microbe-microbe interactions may affect in a non-additive manner microbial metabolism and resulting chemosensory cues. Here, we compared effects of microbial mono- and cocultures on growth of constituent microbes, volatile metabolite production, sugar catabolism, and effects on pollinator foraging across two nectar environments that differed in sugar concentration. Growth in co-culture decreased the abundance of the yeast Metschnikowia reukaufii, but not the bacterium Asaia astilbes. Volatile emissions differed significantly between microbial treatments and with nectar concentration, while sugar concentration was relatively similar among mono- and cocultures. Coculture volatile emission closely resembled an additive combination of monoculture volatiles. Despite differences in microbial growth and chemosensory cues, honey bee feeding did not differ between microbial monocultures and assemblages. Taken together, our results suggest that in some cases, chemical and ecological effects of microbial assemblages are largely predictable from those of component species, but caution that more work is necessary to predict under what circumstances non-additive effects are important.

中文翻译：

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花蜜中的微生物共生影响代谢物和对多粉授粉者的吸引力。

微生物的新陈代谢可以塑造对服务资源共存中的动物吸引重要的线索。资源通常被微生物群落所殖民，但是动物与微生物相互作用的实验评估通常侧重于微生物单一培养。这种方法可能无法预测微生物组合的作用，因为微生物与微生物之间的相互作用可能以非累加的方式影响微生物的新陈代谢以及由此产生的化学感觉线索。在这里，我们比较了微生物单培养和共培养对组成微生物生长，挥发性代谢产物产生，糖分解代谢的影响，以及在糖浓度不同的两个花蜜环境中对传粉媒介觅食的影响。共培养的生长减少了酵母Metschnikowia reukaufii的丰度，但没有降低细菌的丰度Asaia枯草。微生物处理之间和花蜜浓度之间的挥发性排放差异显着，而单培养和共培养中的糖浓度相对相似。共培养挥发物的排放与单培养挥发物的添加组合非常相似。尽管微生物的生长和化学感应的提示有所不同，但在微生物单一培养物和组合中，蜜蜂的摄食没有差异。两者合计，我们的结果表明，在某些情况下，微生物组合的化学和生态效应在很大程度上可以从组分物种的化学和生态效应中预测出来，但请注意，在什么情况下非附加效应很重要，需要更多的工作来预测。