title: Diet-related gut bacterial dysbiosis correlates with impaired development, increased mortality and Nosema disease in the honeybee (Apis mellifera).
abstract: Dysbiosis, defined as unhealthy shifts in bacterial community composition, can lower the colonization resistance of the gut to intrinsic pathogens. Here, we determined the effect of diet age and type on the health and bacterial community composition of the honeybee (Apis mellifera). We fed newly emerged bees fresh or aged diets, and then recorded host development and bacterial community composition from four distinct regions of the hosts' digestive tract. Feeding fresh pollen or fresh substitute, we found no difference in host mortality, diet consumption, development or microbial community composition. In contrast, bees fed aged diets suffered impaired development, increased mortality and developed a significantly dysbiotic microbiome. The consumption of aged diets resulted in a significant reduction in the core ileum bacterium Snodgrassella alvi and a corresponding increase in intrinsic pathogen Frischella perrara. Moreover, the relative abundance of S. alvi in the ileum was positively correlated with host survival and development. The inverse was true for both F. perrara and Parasacharibacter apium. Collectively, our findings suggest that the early establishment of S. alvi is associated with healthy nurse development and potentially excludes F. perrara and P. apium from the ileum. Although at low abundance, establishment of the common midgut pathogen Nosema spp. was significantly associated with ileum dysbiosis and associated host deficiencies. Moreover, dysbiosis in the ileum was reflected in the rectum, mouthparts and hypopharyngeal glands, suggesting a systemic host effect. Our findings demonstrate that typically occurring alterations in diet quality play a significant role in colony health and the establishment of a dysbiotic gut microbiome.
authors.affiliation: Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, PO Box 210036, Tucson, AZ, 85721, USA. pmaes@email.arizona.edu.|Department of Entomology, University of Arizona, PO Box 210036, Tucson, AZ, 85721, USA. pmaes@email.arizona.edu.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Maes
authors.affiliation: Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, PO Box 210036, Tucson, AZ, 85721, USA.|Department of Entomology, University of Arizona, PO Box 210036, Tucson, AZ, 85721, USA.
authors.forename: Pedro A P
authors.initials: PA
authors.lastname: Rodrigues
authors.affiliation: ScientificBeekeeping.com, 14744 Meadow Drive, Grass Valley, CA, 95945, USA.
authors.forename: Randy
authors.initials: R
authors.lastname: Oliver
authors.affiliation: USDA-ARS Carl Hayden Bee Research Center, 2000 East Allen Road, Tucson, AZ, 85719, USA.
authors.forename: Brendon M
authors.initials: BM
authors.lastname: Mott
authors.affiliation: Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, PO Box 210036, Tucson, AZ, 85721, USA.|Department of Entomology, University of Arizona, PO Box 210036, Tucson, AZ, 85721, USA.|USDA-ARS Carl Hayden Bee Research Center, 2000 East Allen Road, Tucson, AZ, 85719, USA.
authors.forename: Kirk E
authors.initials: KE
authors.lastname: Anderson
mesh_terms: D000818:Animals; D001516:Bees / Q000382:microbiology*; D004032:Diet / Q000662:veterinary*; D064806:Dysbiosis / Q000382:microbiology*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D016818:Nosema
keywords: 
  Frischella perrara
  ; 
  Snodgrassella alvi
  ; Diet; Ileum; Nosema spp.; gut microbiota; hypopharyngeal gland; mortality; nurse development; rectum; stored pollen