Genetic analysis reveals cryptic speciation in the Yellow bumble bee (Bombus fervidus) species complex
Today is a great day for bumble bee research as one of my dissertation chapters is finally published! Woowhoo! It has taken us a while to get to this milestone, but it is so exciting to finally get our work out there into the world. Ultimately, we hope our research on the Yellow and California bumble bee continues to inspire future investigations into bumble bee evolution, ecology, and taxonomy. Furthermore, we expect our research to contribute to conservation and management plans for these species.
Read about our research in PLoS One: https://doi.org/10.1371/journal.pone.0207080
Bumble bees (Bombus Latrielle) are significant pollinators of flowering plants due to their large body size, abundant setae, and generalist foraging strategies. However, shared setal coloration patterns among closely and distantly related bumble bee species makes identification notoriously difficult. The advent of molecular genetic techniques has increased our understanding of bumble bee evolution and taxonomy, and enables effective conservation policy and management.
Individuals belonging to the North American Bombus fervidus species-complex (SC) are homogenous in body structure but exhibit significant body color phenotype variation across their geographic distribution. Given the uncertainty of the genealogical boundaries within the SC, some authors have synonymized all members of the B. fervidus SC within a single taxon, while others propose an alternative two taxa hypothesis. Operating under the phylogenetic species concept, our analysis supports the hypothesis that there are two independent lineages of bumble bees within the B. fervidus SC. With the current evidence, however, it is not possible to assign valid names to either of them, because both lineages include the color phenotypes found in the original species descriptions of B. fervidus and B. californicus.
Cryptic speciation does not seem to be the product of Müllerian mimicry between the clades, because diverging coloration patterns are observed when the distribution of the clades overlaps. Furthermore, within each lineage there is evidence for strong population differentiation that is correlated with geographic distribution rather than color phenotype. In our study, we demonstrate the importance of obtaining a broad sample of multiple populations when conducting lower-level phylogenetic analyses.
In addition to improving our knowledge of bumble bee diversification patterns, characterizing the evolutionary history of these pollinators provides the foundation needed to guide contemporary conservation assessments and management strategies.
So how do we get genetic data? Well, we first have to go out a catch some bees. Below is a slide show of the places our research has taken us.