Laboratory-reared colonies of Western bumblebee Bombus occidentalis allowed to forage freely produce as many workers as captive colonies on agricultural land at Pitt Meadows, British Columbia, Canada
Whittington R. & Winston M.L. (2004) Comparison and examination of Bombus occidentalis and Bombus impatiens (Hymenoptera: Apidae) in tomato greenhouses. Journal of Economic Entomology, 97, 1384-1389.
The Western bumblebee Bombus occidentalis has declined dramatically in North America. Re-introducing captive-bred colonies is one possible conservation response. This study examined the productivity of laboratory-reared colonies allowed to forage in agricultural land and woodlands at Pitt Meadows, British Columbia, Canada.
In early May 2001, seven 12-week old commercially produced colonies of B. occidentalis were placed outside in wooden boxes provided with sugar syrup. Seven similar colonies were placed inside a 2.5 ha greenhouse at the same site. The indoor boxes were screened, so bees could not leave or enter the hive and provided with sugar syrup, water, and pollen collected by honey bees Apis mellifera, mixed with 50% honey:water solution. Water and pollen were replaced weekly.
There was no significant difference between enclosed and outside colonies in the number of workers per hive throughout the experiment (average between 40 and 90 workers/hive).