No apparent correlation between honey bee forager gut microbiota and honey production

Abstract

One of the best indicators of colony health for the European honey bee (Apis mellifera) is its performance in the production of honey. Recent research into the microbial communities naturally populating the bee gut raise the question as to whether there is a correlation between microbial community structure and colony productivity. In this work, we used 16S rRNA amplicon sequencing to explore the microbial composition associated with forager bees from honey bee colonies producing large amounts of surplus honey (productive) and compared them to colonies producing less (unproductive). As supported by previous work, the honey bee microbiome was found to be dominated by three major phyla: the Proteobacteria, Bacilli and Actinobacteria, within which we found a total of 23 different bacterial genera, including known “core” honey bee microbiome members. Using discriminant function analysis and correlation-based network analysis, we identified highly abundant members (such as Frischella and Gilliamella) as important in shaping the bacterial community; libraries from colonies with high quantities of these Orbaceae members were also likely to contain fewer Bifidobacteria and Lactobacillus species (such as Firm-4). However, co-culture assays, using isolates from these major clades, were unable to confirm any antagonistic interaction between Gilliamella and honey bee gut bacteria. Our results suggest that honey bee colony productivity is associated with increased bacterial diversity, although this mechanism behind this correlation has yet to be determined. Our results also suggest researchers should not base inferences of bacterial interactions solely on correlations found using sequencing. Instead, we suggest that depth of sequencing and library size can dramatically influence statistically significant results from sequence analysis of amplicons and should be cautiously interpreted.

Gut microbiota composition is associated with environmental landscape in honey bees

“…Also noteworthy, is that the taxa represented in different relative abundances in the different landscape types in the current study do not overlap with taxa suggested to trend toward increased prevalence and diversity in more productive colonies (e.g. Lactobacillus species such as Firm‐4) (Horton, Oliver, & Newton, ). Interestingly, Horton et al., () also suggest that overall colony productivity is not consistently correlated with forager gut microbial community.…”

“…Lactobacillus species such as Firm‐4) (Horton, Oliver, & Newton, ). Interestingly, Horton et al., () also suggest that overall colony productivity is not consistently correlated with forager gut microbial community.…”

Honey Bee Gut Microbiome Is Altered by In-Hive Pesticide Exposures

“…Members of Orbaceae and Neisseriaceae such as Gilliamella apicola, Frischella , and Snodgrassella alvi were reported in honey bee guts in several recent studies (Martinson et al, 2012 ; Moran et al, 2012 ; Horton et al, 2015 ; Tarpy et al, 2015 ). These bacteria were described as part of core microbiome of the honey bee gut; however, the functional roles of these bacterial groups are not yet fully understood.…”

Characterisation of the UK honey bee (Apis mellifera) metagenome

“…379 In many animals, the gut microbiota form quasi-stable communities, with individual 380 hosts harbouring somewhat predictable communities of different bacterial taxa. These (48,(66)(67)(68). 386 In the honey bee gut, bacterial numbers are highest in the rectum, followed by the 387 ileum, mid-gut and crop (66).…”

“…In addition, changes in microbiota composition 3 3 2 (dysbiosis) have been associated with the promotion of disease states in humans 3 3 3 and other mammals (64, 65). Dysbiosis in honey bees may be an important correlate 3 3 4 of bee and colony health (48,(66)(67)(68). 3 3 5 In the honey bee gut, bacterial numbers are highest in the rectum, followed by the 3 3 6 ileum, mid-gut and crop (66).…”