Project Scope Bee Management & Integrated Treatment (BMaT)
Project Target Establish guidelines for bee management in relation to the use of Varroa resistant stock, especially in relation to reduced treatments against Varroa.

Current Status , Assumptions and Proposed solution
– Problem definition
– Current solutions
– Expected future solutions, trends.
– Proposed solution
Those Varroa resistant traits which have shown to be heritable can be used for the selection of more resistant strains of bees. However, it has been shown that several environmental factors (like climate, honey/pollen flow) play big roles in the growth of Varroa populations. Also beekeeping practices can play a role as for example the management and availability of brood in certain periods of the year can be different depending on the beekeeping method. Thus, beekeeping methods also impact the application of treatments against Varroa.

A large impact however can potentially be the use of different sizes of cell-size. Several “schools” of beekeepers and scientists have studied the effect of different cell-sizes on growth of the Varroa population in bee colonies. In short – several beekeeping groups believe that the current most used cell-size foundation – 5.4 mm for worker cells is not natural for use in the brood-nest. This 5.4 mm foundation has been used in the last decades as one believed/believes that larger honey bees can transport more honey and have longer tongues to get more nectar.

Smaller cell-sizes (4.9 mm) are believed by some to have a beneficial effect for the colonies in regard to the slower growth of the Varroa: it is easier to keep the brood nest warm (brood is also closer to each other), development time of the (smaller) bee is shorter (so less time for the Varroa-daughters to become adults) and bees would have more time for hygienic behavior (as they would have to spend less time keeping the brood nest warm). But, as stated, several other researchers and beekeepers are convinced that, based on the performed studies, no significant effect of cell-sizes on Varroa growth has been shown.

In this project the effect of small cells (4.9 compared to standard 5.4 cells) on bee stock which has been pre-selected for Varroa resistance will be studied with the hypothesis that bees with a certain Varroa resistant genetic background (VSH) will more strongly perform their trait while being housed in hives with small cell frames (either with artificial foundation or natural-self-built). If such a relation between cell-size and Varroa resistance would exist then it might become easier to select and maintain Varroa resistant stock as one would not need full homozygote VSH lines but would be able to work with either crosses or less-strong selected lines (easier to obtain and maintain).

While getting stock which is more Varroa resistant, some treatment might still be needed. Also during the selection program treatment will be needed to remain colonies alive. Assuming less treatments would be needed, current and new treatment schemes will be evaluated in relation to this lower frequency and in relation to the fit with the possibly adapted bee management practices.

Science & Technology
– Target Technology: available, required
– Approach, Methodology, Tools
Alternative bee management practices like using small cell foundation have extensively documented. So testing (partly) Varroa resistant stock on these cell-sizes can be done without the use of new technologies. Also foundation of different sizes (5.4, 5.1, 4.9) is commercially available.
Project Evaluation
– Potential value
– Probability of success
Changing bee management practices themselves is relatively easy compared to breeding new lines of (Varroa Resistant) bees. So beneficial effects of for example small cells on the control of Varroa would have a large value for the beekeeping community. The probability of success is being estimated very differently by the different “schools” of follower and opponents of the Small Cell. For the described initiatives in this program it is of utmost importance to understand the possible effect and relation of Small Cells and Varroa Resistance anyway.
Project Planning & Resources
– Planning
– Resources & Partners
The Small Cell studies will be coordinated by the foundation and its volunteers. “Small bee”-stocks will be bred (going from 5.4 to 5.1 to 4.9) which will take at least 1 year. With this stock comparison studies will be started which will likely take a several seasons before final conclusions can be drawn regarding the use of combs with smaller cell sizes – while using (partly) Varroa resistant lines. When smaller-bee stock becomes available, established models in the partner institutes can be used to collect additional information on a possible relation.