title: Variation in honey bee gut microbial diversity affected by ontogenetic stage, age and geographic location.
abstract: Social honey bees, Apis mellifera, host a set of distinct microbiota, which is similar across the continents and various honey bee species. Some of these bacteria, such as lactobacilli, have been linked to immunity and defence against pathogens. Pathogen defence is crucial, particularly in larval stages, as many pathogens affect the brood. However, information on larval microbiota is conflicting. Seven developmental stages and drones were sampled from 3 colonies at each of the 4 geographic locations of A. mellifera carnica, and the samples were maintained separately for analysis. We analysed the variation and abundance of important bacterial groups and taxa in the collected bees. Major bacterial groups were evaluated over the entire life of honey bee individuals, where digestive tracts of same aged bees were sampled in the course of time. The results showed that the microbial tract of 6-day-old 5th instar larvae were nearly equally rich in total microbial counts per total digestive tract weight as foraging bees, showing a high percentage of various lactobacilli (Firmicutes) and Gilliamella apicola (Gammaproteobacteria 1). However, during pupation, microbial counts were significantly reduced but recovered quickly by 6 days post-emergence. Between emergence and day 6, imago reached the highest counts of Firmicutes and Gammaproteobacteria, which then gradually declined with bee age. Redundancy analysis conducted using denaturing gradient gel electrophoresis identified bacterial species that were characteristic of each developmental stage. The results suggest that 3-day 4th instar larvae contain low microbial counts that increase 2-fold by day 6 and then decrease during pupation. Microbial succession of the imago begins soon after emergence. We found that bacterial counts do not show only yearly cycles within a colony, but vary on the individual level. Sampling and pooling adult bees or 6th day larvae may lead to high errors and variability, as both of these stages may be undergoing dynamic succession.
authors.affiliation: Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Hroncova
authors.affiliation: Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Havlik
authors.affiliation: Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic; Institute of Animal Physiology and Genetics v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Killer
authors.affiliation: Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic.
authors.forename: Ivo
authors.initials: I
authors.lastname: Doskocil
authors.affiliation: Bee Research Institute at Dol, Libcice nad Vltavou, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Tyl
authors.affiliation: Bee Research Institute at Dol, Libcice nad Vltavou, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Kamler
authors.affiliation: Bee Research Institute at Dol, Libcice nad Vltavou, Czech Republic; Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic.
authors.forename: Dalibor
authors.initials: D
authors.lastname: Titera
authors.affiliation: Department of Forage Crops and Grassland Management, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Hakl
authors.affiliation: Institute of Animal Physiology and Genetics v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Mrazek
authors.affiliation: Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic.
authors.forename: Vera
authors.initials: V
authors.lastname: Bunesova
authors.affiliation: Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic.
authors.forename: Vojtech
authors.initials: V
authors.lastname: Rada
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D001516:Bees / Q000196:embryology / Q000254:growth & development / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D017753:Ecosystem; D000069196:Gastrointestinal Microbiome; D041981:Gastrointestinal Tract / Q000382:microbiology; D007777:Lactobacillaceae / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S