People began to explore the use of bumble bees for crop pollination in the late 19th century. Bumble bees were intentionally introduced from the UK to New Zealand, which had no native bumble bee species, in order to pollinate red clover plants used for livestock forage. Anyone using bumble bees for pollination at this time was relying on wild populations, as domestication methods had not yet been developed.
The first major breakthrough in bumble bee domestication came in 1912, when F.W.L. Sladen outlined methods for domesticating bumble bees in his book The Humble Bee. With domestication, farmers no longer needed to rely on sporadic wild populations. Bumble bee colonies could be produced and placed directly within crops to provide pollination. However, one major impediment to widespread use of bumble bees for pollination is that colonies could only be initiated from queens caught in the spring after emerging from hibernation. Colonies were only available from later spring through the fall. Bumble bees could not be used for early spring or winter blooming crops.
The second major breakthrough happened in the 1970s, when researchers developed the use of carbon dioxide gas to bring queens out of hibernation early, making it possible to initiate bumble bee colonies at any time. This enabled commercial producers of bumble bees to have colonies available yearround. Bumble bees became the primary pollinator in greenhouses, particularly for tomatoes. Commercial producers, primarily in Europe, began marketing bumble bees worldwide. North American-based rearing facilities were founded in the 1990s, with one species being raised for use west of the Rockies (Bombus occidentalis) and one raised for use in eastern North America (Bombus impatiens).
In 1996, Nosema, a parasite that infects bumble bees, decimated western commercial facilities. It is thought that the infection may have stemmed from transport of a strain of Nosema from European bumble bee colonies. B. occidentalis is no longer viable as a commercially raised species. Wild populations of B. occidentalis and several other related species appear to have dropped dramatically soon afterwards. B. occidentalis was once a common species but is now rare throughout much of its former range. Eastern commercial facilities raising B. impatiens were not affected by this problem. B. impatiens is still available commercially. Since the collapse of western North American rearing facilities, there have been attempts to import eastern species into western states. Due to risks of disease or pest transmission, there has been opposition to these importations. The authors of this book adamantly believe it is best if local western species can be raised for use in western North America.
There are several lessons to be learned from the problems afflicting the honey bee industry: that international movement of bees carries with it the risk of spreading diseases and pests; and that pollination services provided by bees cannot be taken for granted. Since honey bees are not native to North America, there is no option to raise native, local honey bees. However, with over 45 different bumble bee species in North America, we have that option with bumble bees. To prevent the spread of diseases and pests that could decimate both commercial and wild bumble bee populations, it is crucial that local bumble bees are raised for use as pollinators. It is also important that we encourage natural bumble bee populations by providing suitable nesting habitat and ample forage.