Bumble Bees of Montana
Bombus (Cullumanobombus) rufocinctus Cresson, 1863 Red-Belted Bumble Bee
Bombus rufocinctus is a widespread, common bee throughout the Rocky Mountains east through the northern U.S. and Canada to the Atlantic Coast (Williams et al. 2014). In Montana, it is one of the most widespread species, having been collected in nearly every county.
Bombus rufocinctus is one of the species in Montana (along with B. griseocollis, B. nevadensis, and B. auricomus) in which the males have large, bulbous eyes associated with mate seeking and territory defense (O’Neill et al. 1991). While searching for mates, these males are known to perch on plants or structures and chase any moving object (Williams et al. 2014).
Among the bumble bee species in Montana, B. rufocinctus has the most variable color patterns. This variability causes individuals to look similar to many other species and can lead to misidentifications if specimens are not carefully examined. There seems to be no geographic pattern associated with the various color morphs, and an individual colony may produce workers with many different color patterns (Williams et al. 2014).
This species has incredible variation in coloration and superficially can be easily confused with many other species, so using the key for identification is the best strategy when dealing with B. rufocinctus. Characters used for identification include a distinctly shorter-than-wide cheek and black hair on the face. The exoskeleton under the hairs of abdominal T1 and T2 is shiny, and there is usually a distinct band of black hairs between the wings. Abdominal T2 almost always has a crescent of yellow in the middle, while T3 and T4 have hairs that are orange, black, yellow, or some combination of these colors.