When does the yellow-faced bumblebee, Bombus vosnesenskii, typically sting?

Answer

As a defensive reaction to perceived immediate danger, such as being trapped against the skin

When a bumblebee does sting, it is usually a defensive reaction triggered by perceived immediate danger, such as being trapped against the skin or if its nest is physically disturbed.

When does the yellow-faced bumblebee, Bombus vosnesenskii, typically sting?
behaviorinsectbeeface