Environment or genetic isolation? An atypical intestinal microbiota in the Maltese honey bee Apis mellifera spp. ruttneri

Abstract

IntroductionApis mellifera evolved mainly in African, Asian, and European continents over thousands of years, leading to the selection of a considerable number of honey bees subspecies that have adapted to various environments such as hot semi-desert zones and cold temperate zones. With the evolution of honey bee subspecies, it is possible that environmental conditions, food sources, and microbial communities typical of the colonized areas have shaped the honey bee gut microbiota.MethodsIn this study the microbiota of two distinct lineages (mitochondrial haplotypes) of bees Apis mellifera ruttneri (lineage A) and Apis mellifera ligustica and carnica (both lineage C) were compared. Honey bee guts were collected in a dry period in the respective breeding areas (the island of Malta and the regions of Emilia-Romagna and South Tyrol in Italy). Microbial DNA from the honey bee gut was extracted and amplified for the V3-V4 regions of the 16S rRNA gene for bacteria and for ITS2 for fungi.ResultsThe analyses carried out show that the Maltese lineage A honey bees have a distinctive microbiota when compared to Italian lineage C honey bees, with the most abundant genera being Bartonellaceae and Lactobacillaceae, respectively. Lactobacillaceae in Maltese Lineage A honey bees consist mainly of Apilactobacillus instead of Lactobacillus and Bombilactobacillus in the lineage C. Lineage A honey bee gut microbiota also harbors higher proportions of Arsenophonus, Bombella, Commensalibacter, and Pseudomonas when compared to lineage C.DiscussionThe environment seems to be the main driver in the acquisition of these marked differences in the gut microbiota. However, the influence of other factors such as host genetics, seasonality or geography may still play a significant role in the microbiome shaping, in synergy with the environmental aspects.

Stability of the Gut Microbiome in Honey Bees During Harsh Winters and Overwintering Storage

“…Another study on honey bees has identi ed marked differences in the core gut microbial community when comparing different lineages, which include Maltese honey bees (lineage A) to the Italian honey bees (lineage C). Notably, Maltese honey bees exhibited an inverse proportion of Lactobacillaceae and Bartonellaceae when compared to Italian honey bees 40 . The functionality of these differences between bee strains have not been studied.…”

Shotgun Metagenomics Reveals Minor Micro“bee”omes Diversity Defining Differences between Larvae and Pupae Brood Combs

“…At least eight Bacillus species, Lactobacillus, Apilactobacillus, Brevibacillus, Corynebacterium, Leifsonia, one Enterobacteriaceae group and several Actinobacteria were identified in combs [55,56,58]. Amount of microorganisms on hive floors are higher [28], while they contain notably lower concentrations of nutrients [16]. So, there might be a mechanism of comb microbiota control.…”

“…Hive members, their microflora and microorganisms living on different hive substrates influence each other and function together as a superorganism [13,15,16]. The microbiota influences the metabolism [13][14][15]17], development [18][19][20], immunity [21][22][23][24] and even behavior [25][26][27] and evolution and speciation [28,29] of bees. The gut microflora of bees and its role are well studied [13,15,30,31].…”