Gut microbiota composition is associated with environmental landscape in honey bees.

Julia C Jones,William Oh Hughes,Francis Lw Ratnieks,Nicholas J Balfour,Hasan Al Toufalilia,Carmelo Fruciano,Peer Bork,Falk Hildebrand,Philipp Engel

doi:10.1002/ece3.3597

Abstract

There is growing recognition that the gut microbial community regulates a wide variety of important functions in its animal hosts, including host health. However, the complex interactions between gut microbes and environment are still unclear. Honey bees are ecologically and economically important pollinators that host a core gut microbial community that is thought to be constant across populations. Here, we examined whether the composition of the gut microbial community of honey bees is affected by the environmental landscape the bees are exposed to. We placed honey bee colonies reared under identical conditions in two main landscape types for 6 weeks: either oilseed rape farmland or agricultural farmland distant to fields of flowering oilseed rape. The gut bacterial communities of adult bees from the colonies were then characterized and compared based on amplicon sequencing of the 16S rRNA gene. While previous studies have delineated a characteristic core set of bacteria inhabiting the honey bee gut, our results suggest that the broad environment that bees are exposed to has some influence on the relative abundance of some members of that microbial community. This includes known dominant taxa thought to have functions in nutrition and health. Our results provide evidence for an influence of landscape exposure on honey bee microbial community and highlight the potential effect of exposure to different environmental parameters, such as forage type and neonicotinoid pesticides, on key honey bee gut bacteria. This work emphasizes the complexity of the relationship between the host, its gut bacteria, and the environment and identifies target microbial taxa for functional analyses.

Highlights

Individual animals are often considered discrete entities; the microbial symbionts they host are increasingly recognized as key components in their evolutionary and ecological success (Bosch & McFall-Ngai, 2011; Brucker & Bordenstein, 2012; Franchini, Fruciano, Frickey, Jones, & Meyer, 2014; Gibson & Hunter, 2010; Hildebrand et al, 2012; Moran, McCutcheon, & Nakabachi, 2008; Moya, Peretó, Gil, & Latorre, 2008)
Using a custom honey bee bacterial database of currently available genomes of bee gut bacteria, we were able to assign 92% of the sequence reads to species level (99.93% to phylum level, 98% to family, and 95% to genus level) and verify that the major previously identified taxa or strains were present in our data (Neisseriaceae, S. alvi; Orbaceae, G. apicola and F. perrara; Lactobacillaceae, Firm-4 and Firm-5 species groups and Lactobacillus kunkeei); Bifidobacteriaceae; Rhizobiales, Bartonellaceae (Alpha 1; including B. apis); Acetobacteraceae (Alpha 2.1 and 2.2), see (Moran, 2015) and Figure 2)
We find that bees exposed to different landscape types and apiary sites exhibit significant differences in their gut microbial communities, the variance explained by landscape type is relatively low

Summary

| INTRODUCTION

Individual animals are often considered discrete entities; the microbial symbionts they host are increasingly recognized as key components in their evolutionary and ecological success (Bosch & McFall-Ngai, 2011; Brucker & Bordenstein, 2012; Franchini, Fruciano, Frickey, Jones, & Meyer, 2014; Gibson & Hunter, 2010; Hildebrand et al, 2012; Moran, McCutcheon, & Nakabachi, 2008; Moya, Peretó, Gil, & Latorre, 2008). A combination of 16S rRNA community surveys and metagenomics studies has shown that the gut community of worker honey bees is dominated by nine bacterial species clusters that make up 95%–98% of the community (Babendreier, Joller, Romeis, Bigler, & Widmer, 2006; Corby-Harris, Maes, & Anderson, 2014; Jeyaprakash et al, 2003; Martinson et al, 2011; Moran, Hansen, Powell, & Sabree, 2012; Sabree, Hansen, & Moran, 2012). The current paradigm is that the core bacterial community of honey bees is relatively constant across populations and geographical areas (Cox-Foster et al, 2007; Jeyaprakash et al, 2003; Martinson et al, 2011; Mohr & Tebbe, 2006; Moran et al, 2012; Sabree et al, 2012) We test this by comparing the gut microbial communities of honey bees in two landscapes using 16S rRNA gene profiling.

| MATERIALS AND METHODS

| DISCUSSION

Findings

CONFLICT OF INTEREST