Bee-Breeding Project — Lab Note 3.02

For the last two years, we’ve been trying to breed mite-tolerant bees out of regular packages here in southern Wisconsin. Read more about our theory and methods in our grant application. Our project has been funded by the Blooming Prairie Foundation and the native-seed producer and plant nursery Agrecol, which also hosts our hives. We had serious die-off this last winter (more about that below) and this year we’ve got to start over. In essence, we’re repeating the protocols we developed last year, which we shared in the first lab note.

Winter Die-Off

Last year, beekeepers saw an average 44 percent die-off of their hives. We had 100 percent. Most beekeepers attribute their loss of hives to mites and other maladies. We went into the winter with about 55 hives. We lost about 40 earlier in the winter, either to mites or mice. These hives were full of mice by January. It is not possible to tell if the hives died of mites and then mice moved in, or if the mice moved in and killed the colonies (or a mix of both). The remaining 15 hives died during a late-season cold snap.

This is unsustainable. Since our goal is a sustainable apiary system, this does not bode well. We have two working hypotheses. One is that this rural setting has significantly more mouse pressure than we expected. If the mice killed 40 of our hives, this has nothing to do with mites. To combat this, we have added mouse guards to all hives.

Hypothesis two is systemic and scary: commercially available bees do not have a wide enough pool of genetics to have mite-tolerant traits. This random sample of packages might just not have the genes we are trying to isolate. Although this worked in Sweden, Wales, and Africa, they do not have commercial-industrial beekeeping like we do here. To test this hypothesis, we are running the test again. If we get 100 percent die off again, we will have to rethink our entire model.

A mid-winter visit to the apiary to inspect dead hives at one of our five clusters. Some were accessible by walking but others required skis.

Early Summer Update

This spring we installed 20 packages, consisting of ten Russian hybrids, five Carniolans, and five Italians. This year, we installed on April 6, two weeks earlier than last year. Also, we had hives with drawn comb and plenty of honey. This means our colonies have everything they need and more time to build up strong throughout the spring.

By late May, we were able to start splitting our hives, using an updated protocol as compared with last year:

  1. Identify the strongest hive in each cluster of four colonies.
  2. Confirm colony has at least six frames of brood, preferably more.
  3. Find the queen from the strongest hive and place her and her frame of brood in an empty hive with drawn comb with two frames of honey and another frame of brood, plus shaken nurse bees.
  4. Leave as many frames with less than 36-hour-old larvae and eggs as possible in the original hive.
  5. Come back to the original hive 5–7 days later and examine for queen cells.
  6. Leave at least one good queen cell in the original hive and split out the remaining cells to new colonies in deep boxes.
  7. Provide these new splits with resources (2 fr. honey, 1-2 fr. brood, shaken nurse bees) from other colonies to equalize the cluster.
  8. Potentially split other hives in the cluster as needed (i.e., strong hives or those with active queen cells).
  9. Return 28 days after the initial split to be sure each hive has a laying queen.

We have five bee yards around the Agrecol fields (NW-1, NW-2, NE-1, SE-1, SW-1). Each yard started with four hives (two Russian hybrid, one each Carniolan and Italian). We inspected them a few weeks after installation and marked the strongest hive in each yard for splitting. By splitting the strongest hive at each cluster, we raise queens with genetics with quick-growing populations. After splitting this last week, we’ve got seven or eight hives at each cluster. We are likely to split a hive or two at each cluster in the next few weeks, bringing us up to close to sixty hives total going in to the heavy pollen period.


Thanks to our increasing vaccinations here in Wisconsin, we were glad to take on volunteers this year! A big thanks to those who have spent time out in the apiaries (see some pictures from a volunteer on instagram). Follow this link to learn about volunteering yourself.

“Lab Notes” are a series of posts chronicling the daily progress our research projects. Research Project No. 3 is the testing of a bee-breeding protocol to develop mite-tolerant bees from commonly available stock. These notes may be useful for anyone interested in testing such a method at home. Others might prefer the more succinct guide to bee breeding, videos, and other formal publications that will result from this research project and be posted to the website as they are available.

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