Lactic acid bacteria (LAB) are well recognized beneficial host-associated members of the microbiota of humans and animals. Yet LAB-associations of invertebrates have been poorly characterized and their functions remain obscure. Here we show that honeybees possess an abundant, diverse and ancient LAB microbiota in their honey crop with beneficial effects for bee health, defending them against microbial threats. Our studies of LAB in all extant honeybee species plus related apid bees reveal one of the largest collections of novel species from the genera Lactobacillus and Bifidobacterium ever discovered within a single insect and suggest a long (>80 mya) history of association. Bee associated microbiotas highlight Lactobacillus kunkeei as the dominant LAB member. Those showing potent antimicrobial properties are acquired by callow honey bee workers from nestmates and maintained within the crop in biofilms, though beekeeping management practices can negatively impact this microbiota. Prophylactic practices that enhance LAB, or supplementary feeding of LAB, may serve in integrated approaches to sustainable pollinator service provision. We anticipate this microbiota will become central to studies on honeybee health, including colony collapse disorder, and act as an exemplar case of insect-microbe symbiosis.

A polyphasic taxonomic study of the two subspecies of Paenibacillus larvae, Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens, supported the reclassification of the subspecies into one species, Paenibacillus larvae, without subspecies separation. Our conclusions are based on the analysis of six reference strains of P. larvae subsp. pulvifaciens and three reference strains and 44 field isolates of P. larvae. subsp. larvae. The latter originated from brood or honey of clinically diseased honey bee colonies or from honey of both clinically diseased and asymptomatic colonies from Sweden, Finland and Germany. Colony and spore morphology, as well as the metabolism of mannitol and salicin, did not allow a clear identification of the two subspecies and SDS-PAGE of whole-cell proteins did not support the subspecies differentiation. For genomic fingerprinting, repetitive element-PCR fingerprinting using ERIC primers and PFGE of bacterial DNA were performed. The latter method is a high-resolution DNA fingerprinting method proven to be superior to most other methods for biochemical and molecular typing and has not previously been used to characterize P. larvae. ERIC-PCR identified four different genotypes, while PFGE revealed two main clusters. One cluster included most of the P. larvae subsp. larvae field isolates, as well as all P. larvae subsp. pulvifaciens reference strains. The other cluster comprised the pigmented variants of P. larvae subsp. larvae. 16S rRNA gene sequences were determined for some strains. Finally, exposure bioassays demonstrated that reference strains of P. larvae subsp. pulvifaciens were pathogenic for honey bee larvae, producing symptoms similar to reference strains of P. larvae subsp. larvae. In comparison with the type strain for P. larvae subsp. larvae, ATCC 9545 T , the P. larvae subsp. pulvifaciens strains tested were even more virulent, since they showed a shorter LT 100 . An emended description of the species is given.

We evaluated the antagonistic effects of newly identified lactic acid bacteria (LAB) in the genera Lactobacillus and Bifidobacterium, originating from the honey stomach, on the honey bee pathogen, Paenibacillus larvae. We used inhibition assays on agar plates and honey bee larval bioassays to investigate the effects of honey bee LAB on P. larvae growth in vitro and on AFB infection in vivo. The individual LAB phylotypes showed different inhibition properties against P. larvae growth on agar plates, whereas a combination of all eleven LAB phylotypes resulted in a total inhibition (no visible growth) of P. larvae. Adding the LAB mixture to the larval food significantly reduced the number of AFB infected larvae in exposure bioassays. The results demonstrate that honey bee specific LAB possess beneficial properties for honey bee health. Possible benefits to honey bee health by enhancing growth of LAB or by applying LAB to honey bee colonies should be further investigated.

-The US National Honey Bee Disease Survey sampled colony pests and diseases from 2009 to 2014. We verified the absence of Tropilaelaps spp., the Asian honey bee (Apis cerana ), and slow bee paralysis virus. Endemic health threats were quantified, including Varroa destructor , Nosema spp., and eight honey bee viruses. Varroa loads varied across years, with annual fall peaks; Nosema peaked January to April. Migratory beekeepers had significantly lower Varroa prevalence (84.9 vs. 97.0 %) and loads (3.65 ± 0.28 vs. 5.99 ± 0.22) than stationary operations, while Nosema was more prevalent (59.9 vs. 46.7 %) in migratory colonies. Since 2010, chronic bee paralysis virus prevalence doubled annually. We detected strong positive relationships between V. destructor and Varroa -transmitted viruses, between Nosema and Lake Sinai virus 2, and a positive relationship across several viral pathogens of bees. The results provide a disease baseline to help identify drivers of poor bee health.Apis mellifera / disease survey / pests / parasite / USA