Bacterial communities associated with honeybee food stores are correlated with land use

Abstract

Microbial communities, associated with almost all metazoans, can be inherited from the environment. Although the honeybee (Apis mellifera L.) gut microbiome is well documented, studies of the gut focus on just a small component of the bee microbiome. Other key areas such as the comb, propolis, honey, and stored pollen (bee bread) are poorly understood. Furthermore, little is known about the relationship between the pollinator microbiome and its environment. Here we present a study of the bee bread microbiome and its relationship with land use. We estimated bacterial community composition using both Illumina MiSeq DNA sequencing and denaturing gradient gel electrophoresis (DGGE). Illumina was used to gain a deeper understanding of precise species diversity across samples. DGGE was used on a larger number of samples where the costs of MiSeq had become prohibitive and therefore allowed us to study a greater number of bee breads across broader geographical axes. The former demonstrates bee bread comprises, on average, 13 distinct bacterial phyla; Bacteroidetes, Firmicutes, Alpha‐proteobacteria, Beta‐proteobacteria, and Gamma‐proteobacteria were the five most abundant. The most common genera were Pseudomonas, Arsenophonus, Lactobacillus, Erwinia, and Acinetobacter. DGGE data show bacterial community composition and diversity varied spatially and temporally both within and between hives. Land use data were obtained from the 2007 Countryside Survey. Certain habitats, such as improved grasslands, are associated with low diversity bee breads, meaning that these environments may be poor sources of bee‐associated bacteria. Decreased bee bread bacterial diversity may result in reduced function within hives. Although the dispersal of microbes is ubiquitous, this study has demonstrated landscape‐level effects on microbial community composition.

Different Dynamics of Bacterial and Fungal Communities in Hive-Stored Bee Bread and Their Possible Roles: A Case Study from Two Commercial Honey Bees in China

“…In conclusion, two species of honey bee that had different floral sources had similar core communities of microbes but different community structures. We suggested that hive geographical sites might impact the microbial community through pollen more than species and floral source factors [85]. The results of this study could support the pollen preservation hypothesis of Anderson and colleagues (2014) [26].…”

“…Interestingly, Acinetobacter, aerobic genera that are found in many environments, was scarce in the corbicular pollen, but the population increased in the hive-stored bee bread. This microbial-association has been reported commonly in corbicular pollen [67,84] and hive-stored bee bread [26,85]. Two species of Acinetobacter have been found as novel species in the nectar of a wild plant in the Mediterranean: Acinetobacter nactaris and Acinetobacter boissieri [86].…”

Transitions in symbiosis: evidence for environmental acquisition & social transmission within a clade of heritable symbionts

“…Here, localised spatial pattern reflects shared exposure to reservoirs of infection, with colonies originating from the same apiary often overlapping in foraging area [90]. Relevant here are reports of Arsenophonus associated with pollen and nectaring sites [42,84], providing further evidence for environmental transmission [84]. Other processes, such as drifting of infected bees within apiaries, could also drive inter-colonial transmission of Arsenophonus and feedback to drive the localised infection prevalence we observed.…”

“…An economically important eusocial host, the Western honey bee (Apis mellifera), has previously been associated with Arsenophonus [39][40][41][42][43] and infection has been linked to poor health outcomes [44] including colony collapse disorder [45]. Whilst this interaction has attracted interest from the community, basic information on the epidemiology and transmission of Arsenophonus in honey bee populations is nevertheless lacking.…”

Microbial Diversity Associated with the Pollen Stores of Captive-Bred Bumble Bee Colonies

“…Based on this criterion, the shared core microbiota of the two commercial sources was restricted to only two putative pollen fermenters, Lactobacillus and yeasts of the Wickerhamiella/Starmerella (W/S) clade. Past research indicates that both groups perform unique beneficial functions for their hosts, including fermentation and long-term preservation of hive-stored pollen across managed and wild bee populations [24,44,49,50,57,76,[87][88][89]. Lactobacilli are ubiquitously associated with multiple genera of bees, spanning a variety of locations, environmental conditions, and genetic traits [23,79,90].…”