There are different species of leafcutter bees, but the only one to be domesticated is the alfalfa leafcutter bee (Megachile rotundata). This bee, which got its name from pollinating alfalfa so well, was not always in Canada, or even in North America. This species was accidentally introduced into the Eastern United States from Europe or Asia Minor, sometime around the 1930s.1 Since then the population has spread, but it did not reach Canada because it could not survive the harsher climate. Because of the bee's pollination skills, Pacific Northwest scientists, from federal and state departments of agriculture, began to research and experiment with its management2 to domesticate it.

In the first half of the twentieth century, alfalfa seed production decreased because of expanding agriculture and land clearing, which destroyed nesting sites and habitat of native bees. Certain native species of leafcutter bees, and honeybees were relied upon for alfalfa pollination.3 By 1950 Canada was importing alfalfa seed to meet 95% of its domestic needs.

The alfalfa leafcutter bee became famous when it was first introduced into Western Canada in 1962,4 in an attempt to save the alfalfa seed industry- and it worked! Largely due to research work by Agriculture and Agri-Food Canada, Canada began meeting and exceeding its demand for alfalfa seed due to the alfalfa leafcutter bee.

All leafcutter bees are solitary, but the alfalfa leafcutter bee is the only one that is gregarious, meaning the females will nest very close together (and one of the main characteristics that allowed this species to be domesticated). Leafcutter bees are also easily domesticated because they will live in man-made nests, which can be moved indoors to protect the overwintering larvae. The bee larvae go into cocoons, which can be incubated and managed until the alfalfa flowers bloom.5 The bees are perfect for use in one field, because they will fly no farther for food (nectar and pollen) than is necessary, and are therefore more likely to stay in one spot.6

Interestingly, the alfalfa leafcutter used to be called "the soda-straw bee,"7 a name derived from the practice of making bee nests out of drinking straws. However, this practice changed around 1963, when a new way of providing tunnels for the bees was discovered and is now used as the standard nesting practice. Long tunnel spaces are formed when grooved boards are aligned and layered together, making an attractive place for the bees to make egg cells. The grooved formation of the boards also makes removing the cells fairly easy and the "hive" does not have to be destroyed in the process.

During the process of trying to find the best solution for managing alfalfa leafcutter bees, large 'hive' shelters were designed to house dozens of hives and hold enough bees to fill all the hive tunnels with egg cells. Each hive was made with enough grooved boards to create about 3,000 tunnels for nesting.8 These shelters were then put out into the alfalfa field and the bees returned to it when they were done foraging.

The female bees mate and then feed on nectar and pollen. Upon locating the tunnel they wish to use, the females then collect pieces of plant leaves, which they cut with their mandibles and hold under their bodies with their legs. The leaves are used to make egg cells inside the nest. Plant sources must be provided around the nesting shelter, for example, alfalfa, clover, buckwheat, roses, lamb's quarters and sage.9

The management of alfalfa leafcutter bees is highly specialized, and requires specialized equipment and proper handling of bees. A "loose-cell" system of management is used to manage the bees,10 and involves the careful removal of the individual cocoon cells (with larva inside) from the hive tunnels. Then, after careful cleaning, the cells are put into incubation trays or storage containers. With temperature-controlled incubation, adult bee emergence can be synchronized with alfalfa bloom. The nesting blocks are stored at 4 degrees C until about three weeks before the expected crop bloom, when the temperature is turned up to 29 degrees C to trigger final development of leaf-cutter bee adults. This system works to put the maximum number of bees into the alfalfa crop, at the perfect time, to obtain a high seed harvest, and also have a sufficient return of bees for the next year.

This management system has made Canada the leading producer of alfalfa leafcutter bees. Alfalfa is used as a source of high protein for livestock in pasture and hay mixes.11 There is a worldwide demand for alfalfa seed and alfalfa hay. Almost all of Canadian alfalfa seed is produced in Alberta, Saskatchewan and Manitoba, with exports from those three provinces as well. North America is the world's largest alfalfa seed producing region! Together, Canada and the United States normally produce over 50 million kilograms of alfalfa seed per year.12
 


 

  1. Hobbs, G. A. Beekeeping with Alfalfa Leafcutter Bees in Canada. Bee World 53 (4): 167-173 (1972) England: Bee Research Association.
  2. Ibid.
  3. Hobbs, G. A. Domestication of Alfalfa Leaf-cutter Bees. Canada Dept. of Agriculture. Ottawa: Queen's Printer and Controller of stationary, 1967.
  4. Hobbs, G. A. Beekeeping with Alfalfa Leafcutter Bees in Canada. Bee World 53 (4): 167-173 (1972) England: Bee Research Association.
  5. Ibid.
  6. Hobbs, G. A. Domestication of Alfalfa Leaf-cutter Bees. Canada Dept. of Agriculture. Ottawa: Queen's Printer and Controller of stationary, 1967.
  7. Hobbs, G. A. Beekeeping with Alfalfa Leafcutter Bees in Canada. Bee World 53 (4): 167-173 (1972) England: Bee Research Association.
  8. Ibid.
  9. Richards, K. W. Alfalfa leafcutter bee management in Western Canada. Canada Dept. of Agriculture, Rev 1984.
  10. Manitoba Forage Seed Association. http://www.forageseed.net/index.php?option=com_content&view=article&id=131&Itemid=136
  11. Alberta Agriculture and Rural Development. http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/sis955
  12. Ibid.