Abstract：
OBJECTIVE: Diets and parasites influence the gut bacterial symbionts of bumble bees, but potential interactive effects remain overlooked. The main objective of this study was to assess the isolated and interactive effects of sunflower pollen, its phenolamides, and the widespread trypanosomatid Crithidia sp. on the gut bacterial symbionts of Bombus terrestris males.
RESULTS: Bumble bee males emerged in microcolonies fed on either (i) willow pollen (control), (ii) sunflower pollen, or (iii) willow pollen spiked with phenolamide extracts from sunflower pollen. These microcolonies were infected by Crithidia sp. or were pathogen-free. Using 16S rRNA amplicon sequencing (V3-V4 region), we observed a significant alteration of the beta diversity but not of the alpha diversity in the gut microbial communities of males fed on sunflower pollen compared to males fed on control pollen. Similarly, infection by the gut parasite Crithidia sp. altered the beta diversity but not the alpha diversity in the gut microbial communities of males, irrespective of the diet. By contrast, we did not observe any significant alteration of the beta or alpha diversity in the gut microbial communities of males fed on phenolamide-enriched pollen compared to males fed on control pollen. Changes in the beta diversity indicate significant dissimilarities of the bacterial taxa between the treatment groups, while the lack of difference in alpha diversity demonstrates no significant changes within each treatment group.
CONCLUSIONS: Bumble bees harbour consistent gut microbiota worldwide, but our results suggest that the gut bacterial communities of bumble bees are somewhat shaped by their diets and gut parasites as well as by the interaction of these two factors. This study confirms that bumble bees are suitable biological surrogates to assess the effect of diet and parasite infections on gut microbial communities.
RESULTS: Bumble bee males emerged in microcolonies fed on either (i) willow pollen (control), (ii) sunflower pollen, or (iii) willow pollen spiked with phenolamide extracts from sunflower pollen. These microcolonies were infected by Crithidia sp. or were pathogen-free. Using 16S rRNA amplicon sequencing (V3-V4 region), we observed a significant alteration of the beta diversity but not of the alpha diversity in the gut microbial communities of males fed on sunflower pollen compared to males fed on control pollen. Similarly, infection by the gut parasite Crithidia sp. altered the beta diversity but not the alpha diversity in the gut microbial communities of males, irrespective of the diet. By contrast, we did not observe any significant alteration of the beta or alpha diversity in the gut microbial communities of males fed on phenolamide-enriched pollen compared to males fed on control pollen. Changes in the beta diversity indicate significant dissimilarities of the bacterial taxa between the treatment groups, while the lack of difference in alpha diversity demonstrates no significant changes within each treatment group.
CONCLUSIONS: Bumble bees harbour consistent gut microbiota worldwide, but our results suggest that the gut bacterial communities of bumble bees are somewhat shaped by their diets and gut parasites as well as by the interaction of these two factors. This study confirms that bumble bees are suitable biological surrogates to assess the effect of diet and parasite infections on gut microbial communities.
摘要：
目的：饮食和寄生虫影响大黄蜂的肠道细菌共生体，但潜在的互动效应仍然被忽视。这项研究的主要目的是评估向日葵花粉的分离和相互作用的影响，它的酚酰胺，和广泛存在的锥虫虫。在Bombusterrestris雄性的肠道细菌共生体上。
结果：大黄蜂雄性出现在以（i）柳树花粉（对照），(ii)向日葵花粉，或（iii）柳树花粉掺有向日葵花粉的酚酰胺提取物。这些小菌落被Crithidia感染。或者没有病原体。使用16SrRNA扩增子测序（V3-V4区），与以对照花粉为食的雄性相比，以向日葵花粉为食的雄性的肠道微生物群落中，我们观察到β多样性的显着变化，而不是α多样性的变化。同样，肠道寄生虫Crithidiasp。改变了男性肠道微生物群落的β多样性，但没有改变α多样性，不管饮食。相比之下,与饲喂对照花粉的雄性相比，我们没有观察到饲喂富含苯甲酰胺花粉的雄性肠道微生物群落中β或α多样性的任何显著变化。β多样性的变化表明处理组之间细菌分类群的显著差异，而α多样性缺乏差异表明每个治疗组内没有显著变化。
结论：大黄蜂在全球范围内拥有一致的肠道微生物群，但是我们的研究结果表明，大黄蜂的肠道细菌群落在某种程度上是由它们的饮食和肠道寄生虫以及这两个因素的相互作用所决定的。这项研究证实，大黄蜂是评估饮食和寄生虫感染对肠道微生物群落影响的合适生物替代品。
结果：大黄蜂雄性出现在以（i）柳树花粉（对照），(ii)向日葵花粉，或（iii）柳树花粉掺有向日葵花粉的酚酰胺提取物。这些小菌落被Crithidia感染。或者没有病原体。使用16SrRNA扩增子测序（V3-V4区），与以对照花粉为食的雄性相比，以向日葵花粉为食的雄性的肠道微生物群落中，我们观察到β多样性的显着变化，而不是α多样性的变化。同样，肠道寄生虫Crithidiasp。改变了男性肠道微生物群落的β多样性，但没有改变α多样性，不管饮食。相比之下,与饲喂对照花粉的雄性相比，我们没有观察到饲喂富含苯甲酰胺花粉的雄性肠道微生物群落中β或α多样性的任何显著变化。β多样性的变化表明处理组之间细菌分类群的显著差异，而α多样性缺乏差异表明每个治疗组内没有显著变化。
结论：大黄蜂在全球范围内拥有一致的肠道微生物群，但是我们的研究结果表明，大黄蜂的肠道细菌群落在某种程度上是由它们的饮食和肠道寄生虫以及这两个因素的相互作用所决定的。这项研究证实，大黄蜂是评估饮食和寄生虫感染对肠道微生物群落影响的合适生物替代品。
