Causes of Honey Bee Queen Failure in Commercial Beekeeping Operations

Causes of Honey Bee Queen Failure in Commercial Beekeeping Operations

Summary

Beekeepers are vital to our agriculture and economy as they provide honey bee colonies for pollination services and honey production. In turn, beekeeper profitability and sustainability is affected by the health of their colonies. The North Central Region (NCR) is the top honey producing area in the U.S., and many commercial colonies are transported from the NCR to other states for crop pollination. Honey bee colonies are dying from a number of causes. Commercial beekeepers report ‘queen failure’ as the top reason for colony mortality through annual surveys conducted by the Bee Informed Partnership and through day-to-day conversations. Queen failure will eventually lead to colony death if the bees or beekeeper do not successfully replace her.

We proposed to explore potential causes of queen failure in colonies managed by commercial beekeepers in North Dakota and Minnesota. We collected 20 pairs of apparently healthy and failing queens that commercial beekeepers helped us identify. These queens were processed to determine their morphology, sperm count, sperm viability, and pathogen levels (Nosema spp., viruses, and trypanosomes). Based on a suggestion from a beekeeper, the queens were also processed for the storage protein vitellogenin and housekeeping gene actin. We collected 3g of wax from each colony to quantify the pesticide residues in the beeswax combs. Preliminary results were shared and discussed with the beekeepers. Our final steps will be to receive the pesticide results, finish the paired comparison between the healthy and failing queen groups, communicate the final results with the participating beekeepers and get their feedback, and then communicate with the larger beekeeper community.

Objectives/Performance Targets

We collected failing and healthy pairs of queens from commercial beekeeper colonies and had them processed for mating quality, pathogens, and other health measures. We also collected samples to quantify the health of the colony: beeswax to show pesticide exposure, and adult bees to show parasite and pathogen levels in the worker bees. The beeswax samples are currently being processed and we will have those data by early March. Once the final results are in, we will provide the participating beekeepers with a full report on queens from their own colonies and the overall results. After engaging in a dialogue with these beekeepers, we will work on reaching a broader audience through targeted dialogue, writing articles for the Bee Informed blog and a beekeeper journal (American Bee Journal or Bee Culture), and developing a presentation of the project to be used at beekeeper meetings. This communication will include suggestions for management changes based on the results of this study.

Accomplishments/Milestones

• We reached our goal of sampling 20 queen pairs of failing and healthy queens (40 queens total) from commercial beekeeper colonies over the summer of 2016 by visiting the beekeepers that reported that they had failing queens. If the queens fit our definition of failing and were under 6 months old, then we sampled the queen along with a paired healthy queen from the same yard or a yard close by with the same life history.
• We provided a new queen to the beekeeper for each queen removed, and all beekeepers were financially compensated $50 per queen.
• We shipped the collected queens overnight to the NCSU Queen & Disease Clinic, where they were immediately processed for their morphology metrics and to quantify the number and viability of sperm in each queen’s spermatheca. After the first step of processing, the queens were then put in a -80 freezer to preserve for rt-PCR to quantify the pathogen levels. We decided not to reserve the head and thorax of each queen for pesticide analysis due to the concerns about not reaching the minimum sample weight of 3g. Instead, the whole queen was processed for pathogens. We added the quantification of actin (a honey bee reference gene) and vitellogenin (a storage protein) to the analysis, since vitellogenin can be an indicator of queen health and actin acts as a way to quantify the relative expression of vitellogenin. The suggestion to test vitellogenin came from one of the beekeepers.
• We took and processed adult bee samples from each colony to quantify the levels of the parasitic mite Varroa destructor and gut pathogen Nosema in the worker bees.
• Participating beekeepers were provided with a report showing the queen sperm and morphology results, and worker bee parasite levels.
• We sampled 3g of wax for pesticide analysis from 34 of the colonies (17 queen pairs). Originally, we intended on processing only 10 pairs of wax (20 samples), however we were able to use some of the funds intended for the queen analysis on the pesticide testing.
• We used the collected data to run preliminary paired comparison statistics on the queen pairs for each factor quantified.
• We collected queens from five beekeeping operations with the beekeeper or their crew. We discussed the project one-on one with an additional 16 beekeepers through Tech-Transfer Teams. We also presented the project at the Minnesota Honey Producers Association Meeting to an audience of approximately 50 beekeepers on July 16, 2016.

Impacts and Contributions/Outcomes

We are currently working towards identifying factors that contribute to queen failure and will report the results when the final samples are processed. Once specific factors are identified, we will start to develop possible methods of mitigating the effects of the factor(s) based on ideas that are vetted for feasibility by commercial beekeepers. We have potential to impact the management strategies of beekeepers by sharing the results through an industry journal, presentations at beekeeper conferences, and online. The results from this project can be used to direct the hypotheses and methods of further projects investigating queen failure.

Collaborators: