Methods
Figure 1. Project experimental design, displaying breakdown of location and stock factors and categories of data collected. Boxes and text in gray were not analyzed for this draft project.
Queens were obtained from three locations and thus represent three different genetic stocks: Stock 1 from a local Albertan breeder, Stock 2 from a Hawaiian breeder well-established on the market, and Stock 3, from a new Québécois breeder. 180 queens (60 from each stock) were received at the University of Alberta in early June 2022 and were all assessed via queen behavioural tests and external physical measurements. Queen behavioural tests centered around placement of individual queens in clear plastic tubes and evaluated her response to various stimuli (e.g., response to the tube being tilted, light response). This was done under red light conditions (bees cannot see red light).
After these behavioural tests, 15 queens from each stock were destructively sampled following testing to obtain sperm and ovary metrics. After being freeze-killed, spermathecae (structure where honey bee queens store sperm) were dissected out of the queens and stained with two different dyes (one for dead and one for live sperm). This solution was then diluted on microscope slides and an aliquot transferred to a hemocytometer to count cells; these counts were then converted to absolute numbers of sperm both viable and non-viable. Ovaries were also dissected out and weighed, and ovariole numbers were determined by embedding the ovaries in a paraffin wax block and thin-sectioning them in cross-section.
Figure 2. Map of field experiment locations
Queens that were not destructively sampled were placed in colonies for field experiments. In late June 2022, 15 queens from each stock were established in the following locations (Figure 2):
Beaverlodge: Agriculture and Agri-Food Canada Beaverlodge Research Farm (Peace Region in Northern Alberta)
CDCN: Crop Diversification Centre North (Edmonton, Central Alberta)
Lethbridge: University of Lethbridge (Southern Alberta)
The queens were introduced to nucleus colonies with standardized honey, brood, and adult populations - the original queen was removed a few days prior to introduction. These queens and their colonies were then monitored for the following two years (experiment is on-going and will finish in Spring 2024). Data collected over the course of the experiment included:
In-hive temperature data logged every minute from sensors in the central brood box.
Honey output, with supers (honey-specific hive boxes) weighed when placed on colonies and when taken off
Disease levels at various intervals (disease treatment was standardized across locations)
Colony-level behavioural tests (not analyzed as part of this project)
This experimental design is summarized in Figure 1.