One factor to consider when attempting to rear bumblebees (Bombus spp.) for pollination of crops is potential colony size. Species which emerge from hibernation early and continue to produce workers late in the summer or early fall are likely to have larger colonies. In contrast, Arctic species such as Bombus polaris Curtis and hyperboreus Schonherr may produce only one brood prior to the sexual brood. Richards (1973) reported that colonies of polaris are smaller than colonies of species from lower latitudes in North America. Hobbs (1967) estimated 772 as a maximum colony sue for huntii Greene in southern Canada and over 3,000 bees per colony, based on data from Medler (1959), for huntii found in New Mexico. B. rnedius Cresson in Mexico may reach the same number (Michener and LaBerge, 1954). Dias (1958) reported a potential of 3,056 incarum Franklin from Brazil. Thus, it would appear that under optimum conditions several species from the western hemisphere have sufficient potential colony size for successful semi-domestication for crop pollination.
Husband, Robert W.
"Observations on Colony Size in Bumblebees (Bombus Spp.),"
The Great Lakes Entomologist: Vol. 10
, Article 7.
Available at: http://scholar.valpo.edu/tgle/vol10/iss2/7