Evolutionary trends in <i>Bombella apis</i> CRISPR-Cas systems

Honey bee worker gut microbes have been implicated in everything from protection from pathogens to breakdown of complex polysaccharides in the diet. However, there are multiple niches within a honey bee colony that host different groups of microbes, including the acetic acid bacterium <i>Bombella apis</i>. <i>B. apis</i> is found in the colony food stores, in association with brood, in worker hypopharyngeal glands, and in the queen's digestive tract. The roles that <i>B. apis</i> may serve in these environments are just beginning to be discovered and include the production of a potent antifungal that protects developing bees and supplementation of dietary lysine to young larvae, bolstering their nutrition. Niche specificity in <i>B. apis</i> may be affected by the pressures of bacteriophage and other mobile elements, which may target different strains in each specific bee environment. Studying the interplay between <i>B. apis</i> and its mobile genetic elements (MGEs) may help us better understand microbial community dynamics within the colony and the potential ramifications for the honey bee host.