ch provides farmers with live bumble bee colonies for crop pollination, currently only produces a single eastern bumble bee species, Bombs impatiens. This species is then shipped nationwide, in a situation similar to the blue orchard bee, often far beyond its native range. Many bumble bee scientists now believe that these commercially produced bumble bees are responsible for the introduction of one or more diseases which have decimated several bumble bee species, even causing the potential extinction of one species, Bombus franklini (Franklin's bumble bee).
There is an enormous need for managed agricultural pollinators in this country, but it critical not to import non-local bees, especially near wild areas, even if the bees are represented as being the same species as local bees. The alternatives are to either develop local commercial sources of bees that are native to your region or to rear already widely established non-native species, such as honey bees or the alfalfa leafcutter bee, as managed pollinators.
Cuckoo bumblebees are a few species of bees which live parasitically in the colonies of other bumblebees and have lost the ability to collect pollen (Figure 45).. Before finding and invading a host colony, a Psithyrus female (there is no caste system in these species) will feed directly from flowers. Once she has infiltrated a host colony, the Psithyrus female will kill or subdue the queen of that colony and forcibly (using pheromones and/or physical attacks) "enslave" the workers of that colony to feed her and her young. This female also has a number of adaptations, such as larger mandibles and a larger venom sac that increase her chances of taking over a nest.
Cuckoo Bumblebee. Image Courtesy of Alvesgaspar.
Queen and worker bumblebees can sting, but unlike a honey bees, a bumblebee's stinger lacks barbs, so they can sting more than once. Bumblebee species are normally non-aggressive, but will sting in defense of their nest, or if harmed. Female cuckoo bumblebees will aggressively attack host colony memb