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The Varroa Problem : Part 6B- Small-Scale Breeding

First published in: American Bee Journal, April 2017


Let’s work together. 1

For the hobbyist: Be part of the solution. 2

Work cooperatively. 3

Responsible beekeeping. 6

Mite bombs and drift of mites. 8

Wrap up. 9

Notes and citations. 9

The Varroa Problem Part 6b: Small-Scale Breeding

First published in ABJ April 2017

Randy Oliver


I’m fully aware that the vast majority of beekeepers fall into the recreational or sideline categories.  Encouragingly, it is those non-professional beekeepers that have often been trying the hardest to move to “treatment free” beekeeping.  But such idealism alone is not enough—any breeding program should be grounded in an understanding of the biological processes involved.


Let’s work together

I’d like to move beyond the hostility and blaming that is so common in discourse these days.  We’re all beekeepers, and we all want what’s best for the bees.  So let’s take a moment to imagine that you are holding hands with whatever type of beekeeper that you’ve previously demonized, sing a couple of verses of Kumbaya together, and look at the situation through the objective and unbiased eyes of a biologist/beekeeper.

A starting point would be to read a recent (and perhaps controversial) paper entitled “The Darwin cure for apiculture?” [[1]].  The authors argue that:

Beekeeping interference with natural selection in combination with globalization of industrialized apiculture may have now reached levels, where ill effects are inevitable at the colony level.  Therefore, “think globally, but breed locally” appears an adequate suggestion for honey bee breeders to take advantage of natural selection and to foster local adaptations.

They conclude that:

Since natural selection is the differential survival and reproduction of individuals due to differences in phenotype, future efforts to enhance managed honey bee health should take into account the central role of apiculture in limiting natural selection and compromising colony health via adjusted keeping and breeding of local bees. Here lies a great opportunity for beekeeping in several countries [read that as counties in the U.S.], where economic constraints are no longer leading since beekeeping has become a hobby sector, with dispersed and small apiaries being the rule. Sustainable solutions for the apicultural sector can only be achieved by taking advantage of natural selection and not by attempting to limit it.

I concur with the authors that there is huge opportunity for smaller breeding programs for locally-adapted, mite-resistant stock well suited for stationary beekeeping.  That is not to say that the large queen producers should not continue to produce breeds specifically tailored for migratory beekeeping operations—such breeds being adapted to that specific (albeit artificial) ecological niche [[2]].


For the hobbyist: Be part of the solution

There is no biological reason to expect bees bred for early queen production in subtropical areas to perform well during northern winters (or vice versa).  And there is plenty of evidence that locally-adapted breeds fare better on the local flora, and deal better with local pathogens [[3]].

Practical application:  for non-migratory beekeepers, locally-adapted stock generally performs best.

The map below shows the various ecoregions of the continental U.S. (Fig. 1).

Figure 1.  Stationary beekeepers will likely have the best success if they keep locally-adapted stock.  Ideally, we would have queen breeders producing mite-resistant stock for every ecoregion in the map above [[4]].

Practical application: there is plenty of business opportunity for regional queen producers.

Work cooperatively

Most beekeepers can be considered as “small scale” or “recreational” (although most hives are managed by a relatively few professional operations).   At the county level, individual small beekeepers can work together with each other (and Nature) to further the natural evolution of bee, by propagating regional stocks (which may be just as productive, as well as exhibiting higher survivorship) (Fig. 2).

Figure 2.  The data from Magnus [[5]] indicate that there is far greater genetic diversity in U.S. feral populations compared to that of commercial stocks.  Not only that, but it certainly suggests that the blue C1 mitotype favored by commercial queen producers does not survive well when left to its own devices.

The long-surviving maternal lines of bees in our feral populations are a tremendous resource of traits for regional adaptation and parasite resistance.

Practical application: there will likely be introgression of nuclear [[6]] genes from mite-resistant Africanized bees moving invisibly into our feral populations of European ancestry.  However, as far as I can tell, there is no evidence of linkage between the African’s undesirable defensiveness and their traits for mite resistance.

In Europe, some small-scale beekeepers have learned to cooperate in order to advance breeding for resistance, by monitoring their hives for mites, and then producing and exchanging selected queens.  Let me quote a key point of one program [[7]]:

Within the AGT breeding program, bee breeders are encouraged to refrain from using acaricides on test colonies with an infestation of less than 1 mite/10 g bees in the samples routinely taken during the first [week] of July. Subsequently, these pre-selected colonies are monitored for their mite infestation and bee population development on a monthly basis.

As soon as colonies come close to 10% mite infestation or decrease to less than 10,000 bees, they are taken out of the test to prevent domino effects by an invasion of mites and secondary infections into the remaining population of untreated colonies.

Practical application: note that they go “treatment free” only to the point that the mites start winning—THEN TREAT.  Remember that breeding takes place only at the queen level—there is absolutely no reason to allow colonies to die from varroa.  If a colony doesn’t make the grade, next season, cut out drone brood and replace the queen.  It’s easy for any hobbyist to produce at least a dozen queen cells from any exceptional hive (Fig. 3)—please do so, and share them with your neighbors.

Figure 3.  There are few joys (or responsibilities) in beekeeping better than propagating daughters from exceptional queens.  It’s surprisingly easy to do [[8]].

Beekeeping clubs can set up a cooperative mating yard and apiary in which potential breeder queen lines can be compared on an even footing (Fig. 4).

Figure 4.  By starting a bunch of nucs from promising queen mothers all in the same yard, they can be fairly compared to each other as far as performance and mite resistance.  Here my son Eric is standing next to one of our yards.  Most local groups could set up a similar cooperative yard.

The principles that I laid out in Part A of this article all apply.  It’s just that it may be difficult for recreational beekeepers to come up with 1000 nucs each spring.  But don’t let that stop you—figure out how many hives you can put together in a cooperative program.

Practical application: your main limitation will be the isolation of a breeding population.  Locate the most isolated mating yard possible, and offer queen cells to surrounding beekeepers—the next season, the drones from those hives will be of your genetic lines.  The more that you work with the local feral population, the easier it will be (this may be problematic in Africanized areas).

And don’t think that because you are only a hobby beekeeper that you can’t be part of the solution.

Practical application:   John Kefuss points out that “a beekeeper with only one hive might be the one with the biggest ‘pot of gold’–everyone should screen their hives for mite resistance, no matter how small they are.”  And then make sure that the genes of that hive get propagated.

Professional beekeepers can help hobby groups.  For the past several years, I’ve helped two small beekeeper groups to produce locally-adapted mite-resistant stock in their areas.  They raise queen cells from their own selected breeders.  A couple days before the cells are ripe, I supply them with hundreds of queenless nucs.  The hobbyists provide the drone mother colonies in their mating yards.  Once the queens are mated, they can distribute the nucs to surrounding hobbyists, who can then monitor their rate of varroa buildup, and provide breeding stock for the next generation.

In my own county, I’m offering free queen cells to any local beekeeper that is willing to start their own nucs, perform alcohol washes in early July, and agree that if the colony shows signs of resistance, that I can either graft from it, or take the queen back.  The agreement also states that if the colony fails the test, then it must be treated in order to prevent it from becoming a nuisance to our beekeeping community.

Practical application: this is a win-win situation.  The beekeepers get free cells from a queen line bred for mite resistance, and I benefit by them being mated out to drones outside of my operation.  I also now have additional help in screening colonies for productivity and mite resistance.

Support with your dollars

Hobby beekeepers can also help to promote the development of mite-resistant stock by financially rewarding those who have the ability to do so.  Purchase your queens, packages, or nucs from breeders willing to make the effort!  If you can’t find mite-resistant queens in April, then buy them when they become available in your region.

Practical application: Mite treatment is going to cost you–why not spend a bit more money in the first place to reward those willing to produce resistant stock?  Even if that hive requires a natural treatment (such as thymol, formic, or oxalic acid), it’s cheaper than kissing $150 goodbye when it collapses.  If you don’t breed bees yourself, you can be part of the solution by directing the dollars that you spend on queens, nucs, and packages toward individuals, clubs, or programs that are making the effort to produce and provide locally-adapted, mite-resistant stock.

Responsible beekeeping

As a beekeeper, you have a responsibility to the beekeeping community around you, as well as to any struggling feral population in your neck of the woods.  That’s why we have laws in every state about managing American Foulbrood, which can impact surrounding beekeepers.  Well, it’s no different with varroa.

Practical application: if you allow colonies to collapse from varroa/DWV when it’s warm enough for robbing to take place, then you are a nuisance to the beekeeping community around you.  Only if you are isolated from other beekeepers (and better yet, working only with local feral stock) is it justifiable to practice Bond selection.

Although it is laudable for recreational beekeepers to attempt to help breed a “better bee,” unless they understand the evolutionary process of natural selection, they can actually cause more harm than good.  The reality is that if you run fewer than several hundred hives, it’s nearly impossible to maintain a realistic breeding program on your own.

A common misunderstanding: if you start a hive with package bees from a queen producer who treats for varroa three or more times a year (as most do), there’s no biological reason to expect that those bees will magically transform into a resistant colony simply because you wear a “treatment free beekeeper” hat.  Those bees simply lack the genes to do so, and the colony doesn’t have a fighting chance.  And when it then does collapse from Parasitic Mite Syndrome, it will flood your neighbor’s hives, as well as any feral colonies for miles around, with virus-laden mites, thus setting back the natural process of evolution.  Please don’t be part of the problem!

To be part of the solution, you’d need to start with either feral, survivor, or bred mite-resistant stock.  Otherwise, please manage varroa!

There are also the ethical considerations against animal cruelty from neglect.  For example, the Grass Roots Farmers Cooperative [[9]], which prides itself on raising animals humanely, requires their members to control parasites in order to prevent unnecessary suffering of any animals under their care.  And the rules for organic certification of honey require treatment of hives for mites when indicated.  For hobbyists who claim to love their bees, think about the care you give to your other pets (Fig. 5).

Figure 5.  All dogs are infested with the mange mite, but the vast majority of dogs are resistant to mites.  This unfortunate puppy obviously isn’t resistant, and is suffering from mite-induced mange.  Any ethical puppy owner would treat this dog for mites in order to end its suffering (but the dog should then be neutered in order to prevent it from passing on its deleterious genes).  Photo © Brett Cole, by permission.

So let’s say that you leashed up the dog above, proudly put on your “I’m a treatment-free puppy keeper” tee shirt, and took it out for a walk.  Any other dog owner would scowl at you and shy away, in order to keep their dog from picking up the infestation.  And soon, PETA or animal control would be knocking at your door with a charge of animal neglect or cruelty.

Practical application: it’s no different for beekeepers.  You have animals under your care.  If they are suffering from a parasite infestation, either treat them, or euthanize them to put them out of their misery.  Wanting to be “treatment free” is no excuse for animal neglect!  There are several natural and organically-certified treatments that work quite well, and do not contaminate your honey.

I had to agree last year when I heard a speaker point out that if one repeatedly allows package bee colonies to die from willful neglect of varroa, that it is more akin to being a serial killer than a bee-keeper.  Personally, my sons and I cringe at the thought that some of the beekeepers who purchase our lovingly-produced beautiful nucs will later allow them to die an ugly death simply due to neglecting to manage varroa.

Mite bombs and drift of mites

Although it is laudable for recreational beekeepers to hope that they are helping to breed a “better bee,” unless they understand the evolutionary process of natural selection, they can actually cause more harm than good.  Realize that there is a difference between honey bees and most other pets or livestock.  If you allow your chickens or kittens to die from parasite neglect at home, those parasites typically die along with your neglected pets.  Not so with honey bees—the mites in a collapsing colony spread on drifting bees into other hives for a distance of at least two miles in every direction [[10]].

And although many love to refer to themselves as “natural” beekeepers, there is nothing natural about starting with commercial stock, nor in unnaturally increasing the density of colonies in an area.  With the current explosion in recreational beekeeping, the host density of the varroa mite (bee hives) is being artificially intensified by well-meaning beekeepers.  Replacing deadouts the next season with more purchased packages is entirely unnatural, and works against the natural evolutionary process (Fig. 6).


Figure 6.  In a natural situation, invasion of a virulent parasite will reduce the host density as in the map of hives to the left to the point that there is little hive-to-hive transmission of that parasite (red arrows).  This helps the bee population to evolve resistance.  But when we beekeepers artificially maintain an unnatural hive density in an area (right, as in many of our urban areas), we may inadvertently work against the natural evolutionary process, as the “domino effect” of collapsing (poorly)-managed colonies floods any survivors with an overload of mites.

Good beekeepers in many urban and suburban areas are experiencing huge varroa (and sometimes AFB) problems, largely due to well-meaning, but misinformed hobby beekeepers that don’t manage varroa in their hives.  Beekeeping involves a responsibility to both the beekeeping community, as well as to the struggling feral populations of bees, which get hammered when you allow your neglected hives to collapse from varroa.

Practical application: I’m seeing beekeeping clubs across the U.S. shifting from an ideally-motivated platform of promoting non-treatment of hives, to instead working on actually learning to become bee-keepers (as in keeping them alive).  There is no reason that it has to be one or the other—you can keep your bees alive, and also select for mite resistance.

Wrap up

I beg all beekeepers (professional and hobbyist) to become part of the solution to The Varroa Problem.  Either get involved in a realistic breeding program, or support those who are by purchasing stock from them.  And most importantly, monitor your hives for varroa, and treat them (if necessary) before they collapse, so that you don’t become a nuisance to the beekeeping community.

By working together, I see no reason that we can’t solve The Varroa Problem.


Notes and citations

[1] Peter Neumann, P & T Blacquière (2016) The Darwin cure for apiculture? Natural selection and managed honeybee health.  Evolutionary Applications Open access at http://onlinelibrary.wiley.com/doi/10.1111/eva.12448/full

[2] For example, if my beekeeping income were not based upon almond pollination and nuc sales, I would run a breed of bees that shut down broodrearing in August, and then overwintered with a smaller cluster (similar to Russian or Carniolan).  Such a bee would be better adapted to my local conditions.

[3] Meixner, MM, et al (2014) Honey bee genotypes and the environment.  Journal of Apicultural Research 53(2): 183-187.  Open access.

[4] Ricketts, TH, et al (1999) Terrestrial ecoregions of North America : a conservation assessment. Island Press. From Wikimedia. The key to the name of each numbered ecoregion can be found at http://commons.wikimedia.org/wiki/File:Terrestrial_ecoregions_USA_CAN_MEX.svg

[5] The various “C” lineages are from eastern European races, including Italian, Carniolan, and Caucasian stocks; these constituted 84% of the ferals and 98% of the managed bees.  “M” is the Western European lineage, commonly known as the “German” or “Dark Bee”; found in 7% of the ferals, and 2% of managed.  “O” is the Middle Eastern lineage (perhaps derived from long-ago importation of A.m. syriaca), found only in the ferals (about 10%).

Magnus, R and AL Szalanski (2008) Genetic variation in honey bees from south central United States.  Poster at 2008 ESA Open access. 

Magnus, R & AL. Szalanski (2010) Genetic evidence for honey bees (Apis mellifera L.) of Middle Eastern lineage in the United States. Sociobiology 55(1B): 285-296.

Magnus, RM, et al (2011) Mitochondrial DNA diversity of honey bees, Apis mellifera L. (Hymenoptera: Apidae) form queen breeders in the United States. Journal of Apicultural Science 55(1): 37-46. http://www.jas.org.pl/jas_55_1_2011_4.pdf

Magnus, RM , AD Tripodi, AL. Szalanski (2014) Op. cit.

[6] As opposed to mitochondrial.

[7] Buchler, R, S Berg , Y Le Conte (2010) Breeding for resistance to Varroa destructor in Europe.  Apidologie 41: 393–408.

[8] See my slide show at http://scientificbeekeeping.com/queens-for-pennies/

[9] https://grassrootscoop.com/

[10] Recent research from the van Englesdorp lab, as well as:

Frey, E & P Rosenkranz (2014) Autumn invasion rates of Varroa destructor (Mesostigmata: Varroidae) into honey bee (Hymenoptera: Apidae) colonies and the resulting increase in mite populations.  Journal of Economic Entomology, 107(2):508-515.

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