Aside from a single white morning this winter, we have had very little snow in Virginia. The weather is unusually warm and the bees seem to get a flying day once a week or so. I suspect the insect population will be robust this year, from small hive beetles to other assorted insects, due to our lack of cold weather. Soon the bees will start ramping up for spring, and I have been keeping an eye on the mite populations in Mars and Jupiter.
I have screened bottom boards on Mars and Jupiter and count the mites every few days to determine the average daily mite drop. It is nice to track this number through the winter and have a sense of overall hive infestation. As you can see, the mites were high in Mars and had starting creeping up in Jupiter in mid-November. I did an oxalic acid dribble (OAD) on Nov 28 to knock them back. Oxalic acid is an organic compound found in rhubarb, spinach, and a number of other plants. Varroa mites react poorly to it, while the bees have a natural tolerance. I treated every hive in the apiary, which is recommended since the bees (and mites) will drift from hive to hive.
Right now the mite counts are low, around 1 to 2 mites per day. Soon, as the hives start to raise new workers, the mites will increase. Last year the uptick started in mid-February, so we’ll see when it starts changing this year.
The Varroa Problem
Speaking of our most dreaded pest, it appears that nationwide mites are starting to show some resistance to the most common synthetic pesticide, amitraz. I wouldn’t touch the stuff, but many commercial beekeepers use it. This could create some serious trouble for these outfits as well as crops such as almonds that heavily depend on bee pollination. The situation prompted Randy Oliver at Scientific Beekeeping to create a series of articles calling for a new focus on developing mite-resistant honey bees. Visit his articles by publication date page to see the series so far: part 1 through part 4 as of this posting.
The articles provide an in-depth look at why varroa mites are a problem and what we should do about it. Varroa is a vehicle for deformed wing virus (DMV) and other viruses, and as the mite population increases it spreads DMV and other ills among the bees. Colonies will typically collapse from these viruses before the mites become a serious threat.
The most interesting section for me is part 3, where Randy discusses why varroa mites and DMV are getting progressively more virulent. Since commercial beekeepers tend to use bees bred mainly for growth and honey production, the resistance to varroa and DMV in these bees is rather low. This coupled with the fact that hives are kept close to each other encourages more dangerous forms of the virus to develop. If a hive collapses quickly, other bees will rob it out and bring the mites and viruses back to their hives.
If beekeepers insisted on more mite-resistant stock, the virus would spread less quickly. Hive collapses would be more likely to occur during winter, rather than before it. Virus and mite transmission would then more frequently occur in swarms and splits, which would favor less virulent strains of the virus.
Randy does a better job explaining the science (which I may not have completely correct), the point is that the majority of beekeepers would need to insist on mite-resistant stock. In fact, according to Randy, that is exactly what happened in South Africa. The beekeepers there did not have the resources to purchase miticides when varroa arrived. After devastating losses for a few years, the bees recovered and now beekeepers in South Africa do not generally worry about varroa mites. We are unlikely to eliminate the mites, we need to evolve into a more stable relationship between honey bees and mites.
It is a great series, and I look forward to future installments. Check it out.
The Times They are a-Changin’
This 1964 song by Bob Dylan was the title track on the album of the same name. Dylan wrote the song to capture the feeling of change in the 60’s, and numerous bands have performed the song as a cover since then. In 1984, Steve Jobs recited the second verse of the song during the Apple shareholders meeting, where he famously unveiled the Macintosh computer.
For this post, the times are changing for me in a number of ways. Aside from the seasonal change of the bees as we move from winter to spring, I just left my prior job this past week after over five years with the company. My new position starts on Monday, February 6, so cross your fingers for me.
We can also hope that the sense of change will take hold in the beekeeping world. It is difficult for any one beekeeper, especially a hobby beekeeper, to make an impact on the genetics of North American honey bees. We need the major queen breeders to start selecting for mite resistance, something they tend not to do today. So keep your eyes open and don’t speak too soon, cause the times they are a-changing.
May you prosper and find honey.
9 thoughts on “Our Hives They Are a-Changin’”
Thanks for the links and I hope your first days at the new job go well.
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Thanks, Emily. I was wondering if amitraz is used in England? I have seen you prefer acid-based treatments on your blog. Is amitraz something used there as well?
Hi Eric, oxalis/formic acid and thymol based treatments are popular here. I have never heard of Amitraz being used here and don’t think it’s one of the legally approved medicines.
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Good post! Congratulations on your new job! Hope that all goes well for you!
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Thanks, Julie. Hope your hives are doing well.
Congratulations and best wishes for the new job.
The South Africa story is often brought up as a successful nationwide application of the Bond method. But what genetic diversity was lost by such extreme selection pressure on a single trait?
Thanks on the job. Started today and so far so good….
Yes, by definition you lose some diversity when adjusting to a new trait. I’m not sure that the alternative of more and more virulent pests is a good trade off. To be fair, Randy Oliver’s argument is to move in this direction while still using organic treatments. So no wholesale loss of bees during the transition period, and thus probably less loss of diversity.
Tom Seeley’s research in the Arnot Forest found a big loss of diversity of the Mitochondria diversity that come from queens, but little loss of genetic diversity that drones can carry (at least I think that was it). This was between his 1970 studies and his 2000’s collections. He theorized that even failing hives can pump out drones to carry on the family name.