Though the species is not currently experiencing population decline, urbanization has affected its nesting densities, and early emergence of the B. vosnesenskii has been implicated in the increasing lack of bee diversity on the West coast.

The male drones mostly look similar to their female counterparts, but in some cases will have more yellow on their sides that extends farther up the back of the thorax.

[3] Historically, Bombus occidentalis, the so-called "western bumble bee" was the most common species, with a distribution all the way from California to British Columbia and Alaska, but diseases introduced by commercial rearing operations in the eastern United States brought coastal populations of B. occidentallis to the brink of extinction, and B. vosnesenskii has filled the gap.

This may be due to the species' early emergence during the season, allowing it to overtake and monopolize available nest spaces.

[6] In a case study from Santa Barbara, CA - researchers found that local grassland restoration can help support provide habitat refugia for these species in urbanized areas.

It is likely that this is due to the subterranean nesting habits of this bee species, which is negatively effected by the expansion of impervious substances like pavement.

She will then find an underground nest, typically some sort of rodent burrow or some other naturally available hole in wood or dirt.

This behavioral pattern indicates some sort of species-specific chemical cue that initiates recognition and incubation of a brood clump, as opposed to individual body odor or pheromone signals.

There is a high risk of injury or death in foraging, which the queen offsets by allowing the worker bees to do this dangerous task.

However, towards the end of the colony cycle, when the worker population has begun to dwindle, the queen is best used as a forager, to provide sustenance for the next generation of reproductive bees.

While this position is assumed, the abdominal temperature of the queen increases greatly, and metabolism, as measured by oxygen consumption, doubles.

Because of the intense metabolic cost of warming the eggs, they must occasionally take breaks to feed, at which point the brood returns to ambient temperature.

These include: Lupinus, Cirsium, Eriogonum, Phacelia, Clarkia, and Ericameria[2] This bee species shows pollination preferences based on location and landscape features, as opposed to colony membership.

[6] The yellow-faced bumblebee appears to select its foraging locations based on the diversity of available flora in a given region, as opposed to floral density.

This means that the bees are willing to travel longer distances to forage from patches that have wider varieties of available floral taxa.

Additionally, bees which develop preferences for varied plant genera are likely to have more stable food resources over long periods of time.

[17] One theory suggests that bees are able to time their visits better than humans, who typically adhere to a set schedule which may not coincide with floral receptivity.

[17] For the Bombus vosnesenskii, parasitic organisms include the phoretic mite species Kuzinia and the protozoan Crithidia bombi.

Both of these parasites affect individual bees rather than colonies or nests, and have been discovered in relatively high abundance in the Californian B. vosnesenskii population.

Both of these parasites have been discovered in several bees of the Bombus genus, and display a relatively low level of host specificity.