Montana Field Guide

Koch et al. (2018) conducted morphometric and genetic analysis to examine the phylogenetic relationships of Bombus fervidus and Bombus californicus, both of which occur in Montana, and concurred with previous studies that individuals cannot be identified to species based on current taxonomy (i.e., setal color). However, Koch et al. (2018) found: (1) microsatellite genotypes have the capacity to identify two distinct genetic lineages in the Bombus fervidus species complex in areas where the species are broadly sympatric and using the same habitats (including within Montana); (2) sympatric populations within the species complex appear to be phenotypically divergent and reproductively isolated with no evidence of recent introgression (diverging from a common ancestor likely less than ~1 million years ago); and (3) future research evaluating taxonomic characters like wing venation in conjunction with genetic analysis may identify morphological methods for distinguishing between these currently cryptic species.