Haag Karen Luisa, Caesar Lílian, da Silveira Regueira-Neto Marcos, de Sousa Dayana Rosalina, Montenegro Marcelino Victor, de Queiroz Balbino Valdir, Torres Carvalho Airton
Department of Genetics and Program of Post Graduation in Genetics and Molecular Biology, Federal University of Rio Grande Do Sul, Porto Alegre, RS, Brazil.
Department of Biology, Indiana University, Bloomington, IN, USA.
Microb Ecol. 2023 May;85(4):1514-1526. doi: 10.1007/s00248-022-02027-3. Epub 2022 May 6.
Compared to honeybees and bumblebees, the effect of diet on the gut microbiome of Neotropical corbiculate bees such as Melipona spp. is largely unknown. These bees have been managed for centuries, but recently an annual disease is affecting M. quadrifasciata, an endangered species kept exclusively by management in Southern Brazil. Here we report the results of a longitudinal metabarcoding study involving the period of M. quadrifasciata colony weakness, designed to monitor the gut microbiota and diet changes preceding an outbreak. We found increasing amounts of bacteria associated to the gut of forager bees 2 months before the first symptoms have been recorded. Simultaneously, forager bees showed decreasing body weight. The accelerated growth of gut-associated bacteria was uneven among taxa, with Bifidobacteriaceae dominating, and Lactobacillaceae decreasing in relative abundance within the bacterial community. Dominant fungi such as Candida and Starmerella also decreased in numbers, and the stingless bee obligate symbiont Zygosaccharomyces showed the lowest relative abundance during the outbreak period. Such changes were associated with pronounced diet shifts, i.e., the rise of Eucalyptus spp. pollen amount in forager bees' guts. Furthermore, there was a negative correlation between the amount of Eucalyptus pollen in diets and the abundance of some bacterial taxa in the gut-associated microbiota. We conclude that diet and subsequent interactions with the gut microbiome are key environmental components of the annual disease and propose the use of diet supplementation as means to sustain the activity of stingless bee keeping as well as native bee pollination services.
与蜜蜂和熊蜂相比，饮食对新热带区无刺蜂（如Melipona属）肠道微生物群的影响在很大程度上尚不清楚。这些蜜蜂已经被管理了几个世纪，但最近一种年度疾病正在影响四带无刺蜂，这是一种仅在巴西南部通过管理方式养殖的濒危物种。在此，我们报告了一项纵向宏条形码研究的结果，该研究涉及四带无刺蜂蜂群衰弱期，旨在监测疾病爆发前肠道微生物群和饮食的变化。我们发现在首次记录到症状前2个月，觅食蜂肠道中的细菌数量不断增加。同时，觅食蜂的体重在下降。肠道相关细菌的加速生长在不同分类群中并不均匀，双歧杆菌科占主导地位，而乳酸菌科在细菌群落中的相对丰度下降。念珠菌和斯塔默酵母等优势真菌的数量也减少了，无刺蜂专性共生菌接合酵母在疾病爆发期间的相对丰度最低。这些变化与明显的饮食转变有关，即觅食蜂肠道中桉属植物花粉量的增加。此外，饮食中桉属花粉的量与肠道相关微生物群中某些细菌分类群的丰度之间存在负相关。我们得出结论，饮食以及随后与肠道微生物群的相互作用是这种年度疾病的关键环境因素，并建议通过饮食补充来维持无刺蜂养殖活动以及本地蜜蜂授粉服务。
