Selective breeding of honey bees for multiple traits with a priority on nosema disease resistance

Selective breeding of honey bees for multiple traits with a priority on nosema disease resistance

Summary

This report documents the activities during the 2013 calendar year. During spring and summer 2013, 79 new queens were raised from 3 breeder queens selected in spring of 2013. The mother queens were evaluated fall 2012 to spring 2013. Three queens selected from an original pool of 50 were chosen to be breeder queens, or mother queens, for 2013 daughters. Of the 79 daughter queens that successfully mated and were laying eggs in their new colonies, 20 were culled before measures were made by visually determining how well they seemed to be doing in their nucleus colonies. Another 9 were introduced into new nucleus colonies too late in the season to be successful enough to consider their performance on a genetic basis rather than environment.

 Of the 50 colonies that subsequently had selection measures performed on them, 31 were introduced into new nucleus colonies and allowed to build up to full size colonies on their own Another 19 were used to requeen existing, full size colonies. These 50 colonies were overwintered in 1 location and measured for varroa and nosema infestation, brood disease and condition, behavior, and colony strength. 

Objectives/Performance Targets

The primary objectives for 2013 were to

1. Conduct a spring evaluation of 2012 queens
2. Select the best queens to use as mothers in 2013 using the data collected in 2012 and 2013
3. Establish a larger pool of potential breeder queens for 2014
4. Conduct fall measures of 2013 queens
5. Establish numeric data visualization techniques to make comparisons on performance measures.
6. Conduct outreach at beekeeping conferences

Accomplishments/Milestones

1. Conduct a spring evaluation of 2012 queens 

Fifty colonies were started for evaluation in 2012. Of the 35 that where chosen to have selection measures performed on them, 25 survived to February 2013 and had colony strength counts done then. This consisted of a quick count of frames of bees. The following formula was used to convert medium and deep frames to a unified estimate of number of adult bees following Burgett and Burikam,, J. Econ. Entomol 78: 1154 – 1156, 1985.

(# medium frames of adult bees * 1570) + (# deep frames of  adult bees * 2430) = estimated adult bee population

Of those 25 alive in February, 21 survived to March 2013 when a more detailed evaluation was conducted. Varroa mite infestation, nosema infestation, colony strength, brood disease / condition, and behavior (defensive behavior and runniness on the comb)  were recorded. The details of these measures are captured on the 2012 annual report and the data sheet attachment uploaded to the SARE website (see Project Information Products) and the rosecombapiaries.com website.

2. Select the best queens to use as mothers in 2013 using the data collected in 2012 and 2013

To decide which queens to select as mothers in 2012, the raw data was used to determine which colonies performed ‘best’ considering all measures. Graphs of individual varroa, nosema, and colony strength measures were also used to consider the performance on each of these measures separately. These graphs are in the attached power point presentation uploaded to the SARE website (see Project Information Products). It was determined that less subjective methods would be desirable and should be developed for 2014, especially if more colonies were being evaluated.

3. Establish a larger pool of potential breeder queens for 2014

A larger pool of potential breeder queens was established for evaluation in 2014. 79 colonies where initially started with mated queens as opposed to 50 the previous year. To allow for a larger initial pool required less control in variation on the starting colony size. 19 of the 79 potential breeder queens were established in full size colonies and will be evaluated within their own group instead of directly compared to the rest of the colonies which were started in nucleus colonies.

In addition, fewer detailed measures were done to allow more colonies to be included. Evaluations were limited to a detailed evaluation in Fall for 2013, with additional evaluations planned for 2014. Twenty nine of the 79 colonies had no measures done on them because either they seemed to not be doing well in the first place, or they were started late in the season and did not have sufficient time to build up in strength for winter.

In Spring 2013, it was apparent that many colonies died due to high levels of varroa mites. Colonies were therefore treated with Apiguard (a thymol based product) before new colonies were to be established in 2013. In addition, after the Fall 2013 evaluation of new colonies, they were again treated with Apigaurd due to varroa infestations similar to the previous year’s counts. All colonies were treated equally, so evaluations on mite infestation should still be fair comparisons. This was done to allow for a larger pool of potential breeder queens in 2014 by preventing colony death.

No nosema treatments were done through the entirety of the project, so all nosema infestation measures reflect untreated colonies. It was not apparent in the data collected that colony losses were due to nosema infestation. However, statistics have not yet been done to see if there is a correlation to either nosema infestation and strength or an effect of nosema measures on colony death.

4. Conduct Fall measures of 2013 queens

In October 2013, 50 colonies were measured on the basis of nosema and varroa infestation, adult bee population, amount of brood in the colony, and a rating of 1-3 on 5 traits (Brood disease, deformed wings, brood pattern, runny on the comb, defenseive). Techniques used were previously discussed and documented in attachments to this report, uploaded to the SARE website (see Project Information Products).

5. Establish numeric data visualization techniques to make comparisons on performance measures.

To better make objective comparisons between colonies, 2 numerical techniques were developed. 1. Is an index selection formula built into an excel spreadsheet attached to this report (uploaded to the SARE website). The general formula was suggested by Arnold Saxton, University of Tennessee. The weights to each factor in the formula were adjusted based on what I felt was important to select for. Therefore, there is still subjective judgment built into the formula, however it is clear what that is and it is applied equally among all colonies. 2. Another method to better visualize all measures on each colony at the same time, is a bubble chart developed using Google Charts. It is viewable on the Rosecomb Apiaries website at this link http://rosecombapiaries.com/2013/11/breeder-selection-2014/

for the 2013 fall measures. This allows for a visual representation of the measures in 5 dimensions to include all measures of interest in a single graphic representation.

6. Conduct outreach at beekeeping conferences.

Two presentations at regional beekeeping conferences were given to distribute knowledge gleaned so far. One was the 2013 Heartland Apiculture Society conference in Cookeville, TN, July 2013. The presentation was given as a part of a 3 day queen raising mini-course. The second presentation was at the 2013 Tennessee Beekeepers Conference in Cookeville, TN in September, 2013. Slides from these presentations are included in the attached power point, uploaded to the SARE website (see Project Information Products).

Impacts and Contributions/Outcomes

The greatest impact in 2013 is an increased understanding of the steps required to conduct selection measures and activities needed in a small scale bee breeding program. Once I have become practiced in these steps, measures take much less time and increase the overall understanding of pathogen effects on my beekeeping operation. Ideally, much less time can be spent in the future measuring colonies that are unlikely to be chosen as potential breeders. By understanding what is important to measure and when, only those colonies most likely to succeed will have detailed evaluations conducted on them. It was not expected that selection would allow for colonies to not require varroa treatments within this project. If it was that easy, national efforts would have already succeeded. It was however hoped that I could remove nosema treatments from my operation and select colonies that perform well and have low levels of nosema, without treatments. It does appear that this is an achievable goal within this project and evidenced by other beekeepers. More details about this will be included in the final report.

In addition, independence from outside breeding programs and queen rearing operations has been established in my operation by having a large enough pool of high quality queens to select from and raise queens as needed. This was well timed as my outside supplier of breeder queens (Glenn Apiaries) retired from business in 2013. There is not a supplier of instrumentally inseminated breeder queens that meets the combination of low price and mite resistant genetics that this company offered, so moving to relying on my own selection and breeding efforts is needed.

Contributions and outcomes include 50 colonies sold in 2013 with daughter queens from this bee breeding program. Approximately 40 virgin queens were sold to local beekeepers from this breeding program to be mated with stock in the purchaser’s location. The broadest contribution is through information distributed about how a beekeeper can do similar activities through materials distributed on my website and regional beekeeper conferences. A more streamlined recommendation/plan is to be developed in early 2014 to that will allow a continuation of selection measures with a smaller budget of time after the end of this project. This recommendation/plan will be easier for other beekeepers to adopt.

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