 the entrance pipe so it gently slopes up to the surface and clear the vegetation from an area a few inches around where the pipe surfaces.
The best time to install a bumble bee nest box is in early spring, when the first queens have emerged from hibernation and are searching for a nest site; in many areas, this is when the willows first start blooming.
Bumble bee nests require little maintenance. Watch your boxes through the spring and early summer. Any above-ground boxes that are unoccupied by late July can be removed, cleaned and put into storage until the following spring. This is not vital, and if you have a lot of boxes on a large site it may not be practical. In late fall or early winter inspect all the boxes that have been occupied. Remove the old nests, clean them and make any repairs. Cleaning the boxes with a bleach-water solution (1:2 ratios) will help reduce parasites and diseases in the nests. The following spring, add fresh nesting material to all the boxes.
The package bumble bee industry, which 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 members, and sting the host queen, but will ignore other animals (including humans) unless disturbed. Based on my numerous encounters the sting of the bumble bees is considerably more painful than that of a honey bee.
Bumblebees are important pollinators of both crops and wildflowers. Bumblebees are increasingly cultured for agricultural use as pollinators because they can pollinate plant species that other pollinators cannot by using a technique known as buzz pollination. For example, bumblebee colonies are often emplaced in greenhouse tomato production, because the frequency of buzzing that a bumblebee exhibits effectively releases tomato pollen which is normally wind pollinated and therefore difficult to release from the anther.
Bumblebees are in danger in many developed countries due to habitat destruction and collateral pesticide damage. In Britain, until relatively recently, 19 species of native true bumblebee were recognized along with six species of cuckoo bumblebees. Of these, three have become extinct, 