Fall has officially begun! For beekeepers, this is a time for feeding, hive treatments, and overwintering preparations. This fall, ATTTA is busy with overwintering preparations for a project about mass storage of queen honey bees. The logistics of overwintering mass numbers of queens in a bank is continuously being explored in Canadian honey bee research because of the implications it could have on the availability of early spring queens. In this week’s blog, we will discuss mass overwintering of queens by focusing on a recent paper released by researchers in Quebec.
Mass Overwintering of Queen Honey Bees
Queen availability in early spring is a significant obstacle
for the Canadian beekeeping industry. In Atlantic Canada, cool weather makes it
unrealistic to raise queens before June and yet overwintering losses need to be
addressed in May before wild blueberry pollination. As such, it is common
practice to buy imported queens from warmer climates. Mass overwintering of
honey bee queens has the potential to curb this reliance on imported queens,
strengthening our local industry and reducing the spread of harmful pests and
disease.
In 2018-2019, Quebec researchers successfully overwintered
queen banks holding 40 queens per bank for eight months (Rousseau and
Giovenazzo 2021)! Queen banks are colonies with multiple queens stored within.
The queens are kept in cages on a modified frame to protect the queens from one
another and allow access to the workers. Colonies banking queens need to be
fortified with an abundance of food stores and worker bees for the greatest
success (Wyborn et al. 1993). To prepare their queen banks, researchers used 30
colonies to make 15 strong, double brood chamber colonies holding 9-10 frames
of brood and approximately 8kg of bees each (Roussea and Giovenazzo 2021). The
queens were banked in September, then kept outdoors until November when they
were moved indoors at varying ambient temperatures until April. The main
objective of this research was to see if the banks would have greater
overwintering success when stored at a temperature greater than clustering
temperature. To test this, banks were kept at 6°C, 11°C, and 16°C.
There were also 20 control colonies stored at 6°C, in which a single queen roamed
freely.
In May of 2019, the queen banks were opened and queens were assessed.
Banked colonies overwintered at 16°C had the largest number of queens survive
the winter, with an average of 29 queens surviving. The control queens and
banked queens were assessed for body weight, abdomen weight and length, and
sperm viability. Banked queens in all temperatures had significantly lower body
weight and abdomen length, but there was no difference in abdomen width or
sperm viability between banked and unbanked queens. Researchers concluded that
the results of the study are optimistic for Canadian beekeepers. There is
potential to successfully overwinter a large quantity of viable queens to be
ready for use in the early spring. The greatest success in this experiment was
with banks overwintered at 16°C. This is not the industry standard for indoor
overwintering, but it does present an interesting option for queen producers to
explore.
Although the research discussed above shows potential for
overwintering queens indoors, this may not be as practical a solution for
beekeepers in Atlantic Canada. For this
reason, ATTTA undertook a pilot study for mass outdoor overwintering of queens
in the winter or 2021 - 22. This small-scale pilot study demonstrated that
banked queens could survive outdoors in our region. Due to the success of this project and with
additional financial support of the Nova Scotia Beekeepers Association, this
season we are developing the study to include more banks and queens. If this
second overwintering project confirms our initial results, we will develop a more
complete research project to establish practical outdoor overwintering
protocols for beekeeper’s use in the Atlantic region.
Rousseau, A.; Giovenazzo, P. Successful Indoor Mass Storage of Honeybee Queens (Apis mellifera) during Winter. Agriculture 2021, 11, 402. https://doi.org/10.3390/agriculture11050402
Wyborn, M.H.; Winston, M.L.; Laflamme, P.H. Mass storage of honeybee (Hymenoptera: Apidae) queens during the winter. Can. Entomol. 1993, 125, 113–128.
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