The organization called the breeding success of the golden bumble bee a global first for bumble bee conservation, achieved through new overwintering methods. The laboratory colonies of the species produced 1,091 males and 172 new queens in 2024, according to WPC, representing a 30 percent increase from the previous year.
To maintain laboratory operations, the team collected a total of 29 queens of the golden bumble bee and 20 queens of the species known as tri-coloured bumble bee from the wild in 2024.
A species in steep decline since the 1990s
In Canada, the golden bumble bee is classified as a species of special concern; its populations have declined particularly in the southern part of its range including southern Ontario. According to WPC, populations have dropped sharply since the 1990s, and the species has not been documented in most of its U.S. range since 1999. Approximately 50 to 60 percent of the species' global range lies in Canada. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) classified the species as a species of special concern in May 2015 due to observed declines in southern Canada, and in May 2018 it was listed under Canada's Species at Risk Act. Environmental authorities cite disease transmission from managed bumble bee colonies in greenhouses, pesticide use in agriculture and forestry, agricultural intensification, and climate change as primary threats.
How laboratory breeding works
The small laboratory maintains three climate-controlled cabinets for the bumble bee colonies, according to WPC. The insects thrive best at 20 to 25 degrees Celsius with approximately 60 percent humidity. From late August through early October, the team pairs new queens and males for mating. In nature, bumble bee queens spend winter underground; in the laboratory, a temperature and humidity-controlled refrigerator simulates these conditions, with each queen housed in its own tube with sterilized soil.
Progress is evident in comparison to 2022. That breeding season, 75 percent of queens produced eggs, the second-highest rate in the program's history for this species, yet only 17 percent of colonies produced workers and just one colony produced males and new queens. This was still progress: the first time since 2018 that workers appeared, and the first time since 2017 that males and new queens emerged. The largest colony at that time numbered 78 workers. In 2024, colonies of the tri-coloured bumble bee performed significantly better, producing 4,394 males and 223 new queens.
The long-term goal: a self-sustaining captive population
The program's objective is to establish a self-sustaining population of colonies under human care to supplement wild populations, according to WPC. Findings from work with the golden bumble bee and its more common relatives are expected to eventually aid other endangered bumble bee species, including planned reintroduction of the rusty-patched bumble bee in Canada. WPC has identified long-term goals including reintroduction of captive-bred golden and rusty-patched bumble bees to Pinery Provincial Park. In parallel, the laboratory improved its diagnostic capabilities in 2024, adding genomic analysis of bumble bee feces to detect two significant parasites and testing three new pollen diets developed by bee researcher Dr. Mathilde Tissier with new queens.