Effects of live yeasts and their metabolic products on bumble bee microcolony development

Bumble bees can benefit from fungi, though the mechanisms underlying these benefits remain unknown and could include nutrition, resource supplementation, or pathogen protection. We tested how adding living yeasts or their metabolic products to Bombus impatiens diets in a factorial experiment affects microcolony performance, including survival, reproduction, and pathogen presence. We additionally assessed the effects of yeast treatments on diet (nectar and pollen) chemical composition using untargeted metabolomics. Yeasts impacted microcolony reproduction and survival, but effects depended on the source colony. Colonies containing the putative pathogen Aspergillus showed reduced reproduction, but yeast treatments reduced Aspergillus prevalence. Yeast treatments altered the chemical composition of nectar and pollen, but most distinguishing compounds were unidentified. Our results suggest limited direct effects of yeasts via nutrition, resource supplementation, or modification of diets, in..., Microcolonies of B. impatiens (5 workers per microcolony) were created from Koppert queenright colonies and reared on one of four different diets (nectar and pollen), manipulating the presence of 1) live yeast cells and 2) yeast metabolites in a factorial manner. Over four weeks, worker survival was measured daily in each microcolony, and time to emergence of the first adult offspring was tracked. Nectar consumption of a subset of microcolonies was measured over a three day period. After four weeks, all surviving microcolonies were frozen and dissected to remove, count, and weigh developing offspring (eggs, larvae, pupae, adult males). Each microcolony was screened for the presence of the pathogens Aspergillus, Aspergillus flavus, and Ascosphaera apis by dissecting out guts from three workers per microcolony, pooling them, and extracting DNA for PCR (all pathogens) and qPCR (A. flavus only). To measure impacts of yeast treatments on chemical composition of diet ..., , # Data from: Effects of live yeasts and their metabolic products on bumble bee microcolony development [https://doi.org/10.5061/dryad.f1vhhmh5t](https://doi.org/10.5061/dryad.f1vhhmh5t) ## Description of the data and file structure This dataset contains all data and code associated with Effects of live yeasts and their metabolic products on bumble bee microcolony development. This data tests possible nutritional mechanisms through which symbiotic yeasts may benefit bumble bees by factorially manipulating the presence of 1) living yeast cells and 2) yeast metabolites in the diet (nectar and pollen) provided to microcolonies of the bumble bee *Bombus impatiens*. Data consists of performance and behavior metrics for 76 microcolonies (n = 19/treatment), including nectar consumption, worker survival, reproductive output (total and separated by life stage), and pathogen presence and abundance (for pathogens *Aspergillus*, *Aspergillus flavus*, and *Ascosphaera apis*). Additionally, to test..., ,