Dynamic gut dysbiosis in wild bumble bees of southern California

Dysbiosis is well-studied in humans and laboratory models, but its prevalence, predictability, and drivers in nature remain unclear. We addressed these questions by monitoring gut microbiomes of a wild bumble bee (Bombus vosnesenskii) population in Southern California in 2022 and 2024. We found that dysbiosis is highly pervasive, with more than a third of all bees exhibiting dysbiosis. Additionally we sampled the gut microbiomes of three co-occurring bumble bee species (B. melanopygus, B. californicus, and B. sonorus) in 2024 to examine broader dynamics within the bee community at this location.