Bumble bees (genus Bombus) are essential pollinators with broad ecological importance. There are over 250 bumble bee species worldwide, primarily found in temperate and alpine ecosystems. Unfortunately, over the last two decades, declines have been observed in multiple species. Despite all the conservation efforts being done to help bumble bees of North America, little is known about the current abundance, genetic structure, and diversity of threatened populations.

To help fill these gaps, since the year 2019, we have surveyed over 254 California sites for the presence of one endangered (B. crotchii), three vulnerable (B. sonorus, B. californicus, B. caliginosus), and two stable (B. vosnesenskii, B. melanopygus) species. Bombus crotchii is likely to be placed on the California Endangered Species List, and the vulnerable species appear to be declining significantly. B. vosnesenskii and B. melanopygus are some of the most abundant species in California and will serve as a point of comparison for declining species. This extensive work aims to generate genetic maps to compare potential levels of genetic erosion among species, allowing us to consider how historically restricted versus widespread species patterns might affect genetic change within bees, which will contribute to current and future conservation actions.