There are a growing number of people who believe that treating honey bees to remove varroa mites is bad, whereas non-treatment is good. This is literally the opposite of what government funded experts in bee health say. How can this be so? How can some beekeeping associations actually encourage the idea that not treating for a lethal parasite of honey bees is okay, or perhaps even admirable? On the face of it, it defies logic. This is my take on the non-treatment situation.

Monitoring

The National Bee Unit (NBU) advisory leaflet says: “The signs of varroa infestation may not be obvious until your colonies are heavily infested — by which stage they are at great risk.” So, just because you can’t see mites doesn’t mean your colonies are fine. If your justification for not treating is that “they look alright,” then you are not behaving responsibly. Better to know for sure that they are not burdened with a damaging level of varroa mites by actually carrying out some proper monitoring.

In my opinion, the best monitoring method is an alcohol wash. Actually, my opinion is completely based on the opinions of experienced beekeepers/researchers that I respect, such as Randy Oliver. Nevertheless, other monitoring methods exist, and they are not closely guarded secrets, so you can easily find and try them. If you don’t monitor for mites, then you have no idea what your bees are dealing with. It could be fine, it could be horrible — you just don’t know.

The NBU suggests monitoring four times per year: early spring, after the spring honey flow, at the time of the honey harvest, and late autumn. Many people chose to accept that their bees have mites, and blanket treat all colonies at various points in the season, regardless. This is definitely safer than crossing your fingers and hoping that they are fine. However, if you do that, you may be treating colonies that don’t need it. You will also not be able to spot those that do somehow keep mite reproduction down, and therefore keep mite numbers lower than others.

Natural Selection

Some people think that if we just leave bees alone, they will naturally acquire defences against varroa mites over time. Sure, initially most will die, but from survivors will rise a great new bee civilisation, resistant to mites. One problem with that is the unfortunate fact that European honey bees have not evolved alongside varroa for millennia, as is the case with Apis cerana (Eastern honey bee). Varroa is a parasite that jumped species because of human intervention. Our honey bees hadn’t seen varroa for millions of years, and then, about 30 years ago, they arrived — to devastating effect.

Our bees will mostly be dead within two years if not treated for varroa. Three years, tops. Many of those evolutionary traits that have brought us to where we are now (or 30 years ago) could be lost if we just let varroa run wild. If you have 100 colonies with mites, and you don’t treat, you will probably have just a few left within two years, but maybe none at all.

Lost Genetics

When the vast majority of a population dies, assuming that the survivors can breed and re-grow the population again, we lose a lot. It’s a genetic bottleneck. There are traits that nature has selected, evolved since honey bees existed, or the last near-extinction event. There are also traits that beekeepers have selected for, such as honey production and good temper. Many of these will probably get trashed if the majority of the population is killed by the viruses that prosper due to the varroa mite. That’s a big, and unnecessary, step backwards. We don’t have to let our bees die.

It’s not just a problem of lost genetic diversity, though. If 90%+ honey bees die, commercial beekeeping will also die, along with the associated pollination services that they provide. Ironically, some new beekeepers who take up the noble pursuit because they worry that honey bees are endangered (wrong), are encouraged to try non-treating so that we can create mite-resistant bees (also wrong).

Resistant Bees

Yes, in some isolated places, honey bees have been found that are resistant to mites. My understanding of this is that there are multiple different behaviours involved in achieving resistance. Bees have to use a range of different behaviours, evolved for something else, in various combinations to disrupt mite reproduction to a point where mites cannot breed fast enough to kill the colony.

Randy Oliver has been working for seven years on his mite resistance programme. He has a strong selective pressure, as he uses 30 breeder queens each year, selected from 1,500 colonies. He selects the queens that maintain zero (or very low) mite counts throughout the season without treatment (some actually do exist). However, that is not enough; they also have to be good honey producers, gentle bees, and all the usual things that most beekeepers look for. There is little point in producing resistant bees that are useless to beekeepers. It’s like having dairy cows that make very little milk, or disobedient sheepdogs, or skinny pigs.

After seven years, Randy says he has got to a point where the progeny of his breeder queens have about a 50% chance of possessing the desirable qualities of the mother. This is impressive, but it shows that even after seven years of strong selective pressure, the resistance trait is hard to ‘fix’ in the genetics so that it carries on in future generations. With open-mating, in places like most of the UK, the task becomes almost impossible.

Pass It On

For most of us, breeding the perfect bee is a bit of a tall order. Even if we had such a creature, her daughter queens would mate with the local drones, which are a mixed bag. If all the drones came from a ‘perfect bee’ mother, the chances of continuing the perfection would be good. However, the real world ain’t like that.

Some of the traits that beekeepers seek to propagate are quite easy to pass on to the next generation. I think this might be because those traits are determined by something basic, such as a single piece of their genetic code being switched on or off. However, anyone who raises plenty of queens by open mating will admit that not all daughter queens are little darlings.

In the case of the traits that help make honey bees resistant to mites, there is no simple genetic switch. There are multiple factors involved, and multiple strategies employed by the bees to help keep mite numbers down. Combine this with open mating in an area full of all sorts of mixed up genetics, and you can see why it’s not easy.

Interesting Times

We live in interesting times. Here is an extract from a recent newsletter from a beekeeping association:

Chairman’s Message

“Treatment free beekeeping, that is not using chemicals to treat your bees, is a practice we have always advocated. Recently, it has become a hotly debated topic, following a rather controversial presentation given by a regional bee inspector to a bee club in Wales. Professor Stephen Martin of Salford University, a world renowned expert in this field, has already provided a critical critique of the webinar that highlighted a number of factual errors…”

So, a beekeeping association, responsible for educating beginners, proudly goes against the advice of the National Bee Unit. What’s more, the NBU message is deemed “controversial”. Meanwhile, a biology professor, who used to work at the NBU, is apparently helping the cause of non-treatment by openly criticising some parts of a bee inspector’s message. Interesting times indeed.

Still Worth Trying

In my opinion, as somebody who makes a few queens each season (less than 100), it’s still worth trying to raise daughter queens from my more mite-resistant breeder queens. I know that the trait will only pass on to a few, and that over time it will be diluted out by open mating in subsequent generations, but it is still worth trying. After all, if I monitor for mites I can spot the more resistant colonies, so I might as well breed from them if they are also good bees. I fully accept that I’m not going to make the slightest measurable difference to the gene pool in my area, and as soon as mite numbers exceed 2% (6 mites per 300 bees) I will treat with a varroacide. That is just common sense, right?

Disclaimer

All of my posts on this website are personal, and not representative of any organisation that I work (or worked) for. I’m simply a beekeeping walrus, sharing what I think.