High-throughput sequencing has changed the way we can study the complexity of microbiomes, going beyond just describing the taxonomic and genetic diversity of symbionts. An important part of any microbial community is the mobilome, the set of mobile genetic elements (MGEs). For instance, plasmids can carry important resistance genes or virulence factors, transposable elements can modify gene function and regulation, and phages can kill the host or integrate its DNA. Thus, studying MGEs is essential for a better understanding of the microbiome assembly and function. The microbiome of worker honey bees and its beneficial role for host health has been intensively studied, but the impact or role of the mobilome in shaping the microbiome or the bee’s health is still unclear. This knowledge gap is even more pronounced for bee queens, the sole reproductive unit of the colony. Adam Dolezal and GEMS postdoc Lílian Caesar (Newton Lab) propose to integrate research systems independently developed in the Dolezal and Newton labs to test the effects of diet and workers’ provisioning on queen fitness and then characterize the microbiome and mobilome.