Last year 2015 was a bad year for the bees in more than one respect. Long cold spring and bad summer. But late summer was good as was the autumn. The bees could recover and prepare for next year.

Fresh pollen was low in spring 2015 . The immune system wasn’t at its best. And the bees couldn’t fly as much as they needed. Where nosema was present it could infect new bees instead of disappear with sick bees as those couldn’t make it back to the hive.

I treated more hives and used more Thymol last year than I had done earlier years. Early in the season I saw what was coming and decided to try some new strategies to get forward on the path to better Varroa resistance and finally get rid of chemicals.

Leif Hjalmarsson

Very often I have reminded myself of the experiences from an apiary of Leif Hjalmarsson in the southern part of Sweden. He got 5 Elgon queens from me already in 1997 and established an apiary at least 2 miles from other bees. The bees to which he introduced the queens had been treated with Apistan for about 5 years and were very low in number of mites. The bees had probably been adapted somewhat to the presence of the mite. Leif used large cell size, 5.4 mm. He never had to use any miticide on those bees until he died early this year. I do miss him! He was dear friend and a good beekeeper.

Already when we started to combine the Monticola bee with our Swedish bees there could be seen resistance traits. Therefore I had hoped that Varroa mites would be no problems when they arrived in my apiaries. This would not be the case. Even though I had as well regressed my bees to small cell size, 4.9 mm.

I have been wondering since 2008 when the mite started to create problems, why they were a problem for my bees with me, but not for “my” bees with Leif? Last year I decided I had to let the fact that Leif Hjalmarsson established this apiary of his more than 2 miles from other bees affect how I designed my bee management. I want of course to get better resistance with my bees in my apiaries.

A lot of focus had to be put on avoiding reinvasion, bees picking up mites from colonies with high infestation level of mites, within my own apiaries and others within about 1.5 miles.

Better selection 2015

But the difficult circumstances for the bees last year also meant that selection pressure was stronger and it was easier to choose a good breeder, if there was any. And there were good breeders, especially colony S241 which I have mentioned in an earlier blog post, but also C243. I introduced many new queens in my colonies last year, especially from S241. I had only found one mite in S241 in the brood when I tried to found out the VSH degree. And that mite had no offspring.

1. Project 1, 3 miles from other bees in a forested area started in autumn 2014. I had not treated the colonies in this project in that autumn when the project apiary was established. During 2015 I treated a couple of colonies when they showed crippled winged bees. The varroa level was not alarmingly high, so virus effects came early in infestation. Evidently reinvasion from the colonies with DWV didn’t occur very much to the other colonies in the project apiary, as in autumn 2015 varroa level was low in all colonies. Varroa level was also very low this spring 2016, and so it is now late in summer 2016.

Bee shaker1 The Bee Shaker is a valuable tool in getting a quick and easy figure of the Varroa level in the bee colonies in an apiary. Type in the search box: Bee Shaker – at the top of this blog, and you will find more info about it.

2. Project 2 started late summer 2015 as I treated all colonies in an apiary 1.5 miles from other bees of mine with an effective pesticide/miticide in August that year (I hated to do use it), to mimic somewhat how the apiary of Hjalmarsson was established. The varroa level now in August 2016 was surprisingly low, almost not detectable. It was in this apiary I had planned to reduce Varroa level by removing all capped brood frames twice with a week in between, in those colonies showing higher Varroa level than 3%. The highest level now in August was 0.3%.

Bee shaker2 The Bee Shaker will help you to decide if any colonies has to be removed (or any other action taken) from your apiary in which you are developing the Varroa resistance in your bees. It’s a simple and quick method, but you kill 300 bees. That is though nothing compared to numerous bees dying if you do nothing. Viruses and mites killing thousands of bees besides the normal die offs from worn out bees in their daily work, where tens of thousands of bees are dying.

3. Those colonies I decided last year I would shift queens in this year, I treated with thymol in April/May this spring even if they showed no signs of Varroa or virus symptoms. With this I think I secured that those colonies wouldn’t produce mites that could reinvade the other colonies in the apiary. These kind of apiaries are the most numerous of mine. I have not checked the varroa level in all colonies spring and late summer in these apiaries.

Up til now in late August 2016 I have found this odd colony in just a few apiaries, showing one wingless bee. I have tested those colonies with the bee shaker for the Varroa level and only found a few colonies with a Varroa level higher than 3 %.

In one apiary I had this colony with a decreasing varroa level during the season. Three weeks after the early August measurement with just above 1 % Varroa level, I made a new measurement. Now it showed 5 %! Too many mites for the colony to have produced it during these three weeks. Less than a mile away there is another beekeeper, with Elgon bees, but not selected for Varroa resistance for some years. No wingless bees. The colony had probably picked up the many mites from one of his colonies. I didn’t treat, but gave it a sticky board on the bottom to check the natural downfall. And a new Varroa level check will be done in a month. Hopefully this colony will be able to reduce the Varroa level. We’ll see.

An apiary at the edge

Let’s look at one apiary at the edge of “my” Elgon area. With that I mean that drones from other beekeepers’ bees can influence the matings of virgin queens. Also the risk of reinvasion is of course higher. Last year was of course not only difficult for my bees but also for the bees of other beekeepers. In this apiary I treated two colonies quite a lot last year, and also this spring and shifted their queens. The other colonies in this apiary has not been treated this year. But they were all treated last year with Thymol. Now in August I saw a bee that looked like it had the beginning of wings being crippled in one of those colonies. So I tested the Varroa level, 4 mites in 350 bees = 1.1 % Varroa level. It got no treatment of course. Very pleasing result.

A couple of small apiaries

I have a couple of small apiaries in which I checked all colonies with the Bee shaker in spring this year, 0 or a couple of mites in 300 bees. No colonies treated this spring as I didn’t plan to shift any queens this year. I had shifted some last year. I checked these apiaries now in August.

In one of the small apiaries with two colonies and a split I found 4 mites in one of the big colonies and 32 (!) in 300 bees in the other. This was too many in the later colony for it to be able to produce them by itself. No crippled winged bees. Also a sign of that those mites were picked up from somewhere else. This colony had a history of needing Thymol every year, so I chose to treat with Thymol and am planning to finally shift the queen next year. 500 meter away is double the amount of hives of another beekeeper (with Elgon bees which were not from my selection in recent years). He had had problems with one of his colonies.

The situation in the other small apiary will be described later in a blogg post of its own.

Avoid reinvasion when bees adapt

The conclusion is that it’s very important to avoid reinvasion of mites when your bees are developing their ability to control the Varroa mites. They need mites to do that, but no or few extra mites from other colnies that makes it more difficult for them to survive.

On the other hand can the explanation for the better varroa resistance with my bees, as it seems, partly be explained by the fact that I shifted quite some queens last year to S241-daughters. Bess from their colonies will drift somewhat into other colonies, as bees from all colonies do. In this case these drifted bees may well help controlling the Varroa level and possibly also teaching the original bees of the colony to fight mites better.

Genetics is of course important when bees adapt, changes in the composition of the DNA. Selection by culling the worst and multiplying the best. But bees adapt too quickly for the genetic changes to explain in all. Epigentic changes is of uttermost importance here, changes how the existing DNA is expressed, how it’s used. It’s impossible to explain the resistance developing in S. America and S. Africa in about 5 years in any other way. As epigenetic changes occur when environmental changes act upon the chemical environment closest to the bees. The precense of the Varroa causes chemical changes in the bees, in the brood cells, etc. These epigenetical changes are inherited to next generations until new environmental changes cause other epigenetical changes. We understand that chemical help against Varroa will hinder the bees’ own control mechanisms to develop fully. There will be a balance act of avoiding all kinds of miticides as much as possible without letting the bee colonies die. Avoiding reinvasion will be very important then helping the bees developing their control mechanisms fully.

As was pointed out in a previous blog post, my bees are held on small cells, which may contribute to the very low overall mite level. The mite level in Leif Hjalmarsson’s apiary he didn’t treat for many years was at least in the beginning when we measured substantially higher. He used large cells.

I’m convinced that when the bees have learnt how to control mites effectively they can handle reinavsion of mites as well, maybe also in larger numbers. I would call that VISH (Varroa Intruder Sensitive Hygiene.:)) I suspect this can take some years. Then they probably sometimes need some reinvasion to keep their skill at a high level.

Reinvasion is worst

9 thoughts on “Reinvasion is worst

  • August 26, 2016 at 15:02

    Hi Erik,

    In regard to your small apiary section, you mention that one colony showed a high mite count but showed no signs of viral infection. Perhaps this colony has adapted well to viral load? This seems like an advanced immune system adaptation to me.

    One aspect I have always been struck by was a lecture given by the late Charles Mraz. He thought that all colonies needed to be reproduced in order to form a dense genetic variability in an area to eventually produce a race of bees that would develop vigorous resistance faster to mites, both tracheal and varroa. Tracheal mites are now not much of an issue to most colonies here in USA, but there are occasional reports of problems. This resistance came rather quickly, but certainly the bees paid a heavy toll in the beginning. Perhaps allowing an entire apiary to naturally select the best genetic makeup is more productive than culling queens by human selection? This could result in mites being redistributed among nearby colonies if the beekeeper isn’t attentive enough to monitoring colonies and keeping collapsing colonies form becoming a problem for the entire apiary.

    I also wonder about the apiary of Leif Hjalmarsson. Did he control swarming? Did he split colonies to break brood cycle, which does in fact knock out mite problems by resetting the colony to cleanse brood nest and cull weak and sick individuals? I know from my own apiary that a colony that swarms becomes extremely healthy in the months afterwards. I don’t control swarming, in fact I welcome it! The more natural the colony behavior, the better the over health and longevity it has, in my opinion. Since I haven’t treated any of our colonies in the 7 seasons I have been in Maryland, our apiary has developed a good resistance to mite infestations and viral infections. I do occasionally see some deformed wings, but deformed wings have been found in areas where varroa do not inhabit, like on Maui, Hawaii. A farmer friend there has kept his bees treatment-free for decades and occasionally finds a crawling bee with deformed wings, but not an entire colony being decimated by this viral infection.

    Great article…I look forward to the next entry!!!

    Bill Castro
    Baltimore, Maryland

    • August 26, 2016 at 17:31

      Thanks for your comments Bill
      Your thoughts may be correct. Maybe I did the wrong decision. Last year the apiary consisted only of two colonies and the other one were better in many respects, also concerning Varroa. So I choose to make a split from that one. This split behaves very well also. Last I hadn’t started using the Bee Shaker. I should have in this apiary to be knowing the standard of the colonies better. Last year this other close apiary was there. When a few crippled winged bees occurred I should have used the Bee Shaker. Instead they got some Thymol. As this colony that picked up so many mites showed a less good history I choose to protect the other two colonies in the apiary so I could avoid using Thymol on them and let them develop their resistance without chemicals. If I had not treated the colony that might have turned out to go well. That I will not know now. But if any of my colonies can handle a situation with many picked up mites I will get a test with a better colony as described at another place in the article.
      Mraz has a point here. That’s why I let colonies shift their queens themselves if they don’t cause me any extra job or problems. Colonies that just do their job with little work involved from me are left doing what they want.
      Hjalmarsson did prevent swarming by giving the colony ample room for egglaying and honey. But he didn’t tear swarmcells every week or the like. I’m sure they swarmed somewhat more than his other hives. But how much that was I don’t know. I thou gave him some new queens when some years had passed. And he sometimes also bought a few queens during the years. He shifted in the not so good colonies. The others were allowed to keep their new queens of their own.
      Yes, crippled winged bees can occur without Varroa and their viruses. It did also in Sweden now and then before the times of Varroa. It may occur in spring I understood when the queen is laying heavily. Maybe some pupae got chilled at the late stages of development when the wings are formed.

  • August 28, 2016 at 14:58

    Hi Erik,
    I agree with Bill – the best selection is by the nature. I believe that here is a point in human selection when You just can’t do nothing more.

    Besides Your Elgon genetics seem to be quite ok. I’ve got some of this genetics (I bought some granddaughters of Your queens from polish beekeeper who had some from You – I wrote it some time ago). I bought Elgon nucs in June 2015 – I think they were not treated since autumn 2014 – but for sure they were not treated since I bought them.

    I did no treatments in my apiary in 2015 and this year. However I do lots of splits (“Expansion Model Beekeeping”) – Elgon bees seem to do best as a group. I do no notes, I don’t give my bees numbers so as I have about 50 colonies I don’t quite remeber all the bees where they are 😉 (I don’t want to have any suggestions by genetics – I want just my bees and see them as a whole apiary, not by the single colony). But I still know where are 5 of my Elgons (1 more I’m not sure but I think it is also Elgon) – and as I wrote as a group they seem to be doing best in my apiary. Two of my best colonies are Elgons (measuring build up). I see some varroa on them, I see some DVW in them – but they seem not to care about that 😉 For now they build up nicely – better than others with the same noticable varroa or DVW (I don’t count varroa, because I don’t care about the numbers 😉 I leave it all to nature). I’m just writting this beacause I think varroa count or DVW count may not be the best indicator for surviving…

    I will let You know how (and if) they will winter.
    Bartek from south Poland.

    • August 28, 2016 at 22:06

      Interesting info Bartek. Thanks!
      Yes, bees interact in an apiary. They drift enough to make bees from the best colonies help the others somewhat. And the best will take some of the mites from others. And if enough many can make it to next season chance is good the apiary as a whole will make it better next season, especially if the weather is good.

  • August 28, 2016 at 16:12

    I like especially the part, in which you discuss the difference between genetic and epigenetic effects. Very well explained.
    On the other hand you discuss how your strategies have evolved and that you are still challenged by the results that are coming up, promoting hypothesis and partly speaking agaist others. In principle I learned you become more trustable in the ability of bees to fight varoa on his own. I would say that reflect in general the strategies out there that are going from extreme a) control everything by breeding and selection on the one hand and extreme b) let it go and do as less as possible to give bees room to act as natural as possible (eg. own honey, smaller cells, swarming, not prevent exchanging queens etc). The majority is probably in between and I’m looking forward as Bill to the next stories to learn and getting food for thoughts.
    I personally are very happy with my bees this year, I had 8 colonies with 0 or 1 mite/day (natural downfall). There a lot between 3-8/day and 4 with more than 15, where I have to remove capped brood. The good one I challenged with capped brood from the “loosers” to check their speed, how fast they can get rid of the mites. Because I think, 0 mites/day or low infestation levels are already good, but as you mention it, the ability to get rid of mites in bad years is of importance as well. Hence, i put some extra pressure on the best ones by adding capped brood frames from bad colonies (only some of the best ones), to learn if they can get rid and if yes how fast they are. At the moment (after 2,5 weeks) the two Elgons (F2 from S241 and C243) have 15mites/day, hence it probably need some time to gow down to 0 mites/day. I hope I have not overchallenged these hives, but as these hives are in my garden, I have nearly daily control and can act, in case I have to. Let’s see…:-)

    • August 28, 2016 at 22:11

      Do you see any wingless bees in the test colonies? Those wingless bees could in such a case be said to most probably come from the brood frames from the other colonies. In a way you can say they have started dealing with the mite population as 15 mites/day is lower than more than 15 mites per day. Check again soon. How many brood frames did they get? Maybe it’s one year too early to test them like this. But you’ll know soon enough. Please let us know.

      • August 29, 2016 at 20:30

        Both colonies get 2 brood frames and I saw no DWV bees so far nor on the board.
        I don’t think it is too early, as one of these hives, accumulated mites one year ago up to 16/day and then started to rear a new queen. The queen has been mated in October (kind of stressbreeding), what is really rare in Germany, as temp. are rarely above 20°C. However, it worked out fine (these bees look really Buckfast with yellow stripes, indicating that a pure buckfast mating was taken place). Then mite number dropped to 5/day along autumn and during winter and I was surprised to see 0 mites/day this summer. Hence, the conclusion was, that this hive succesfully get rid of mites, even in an area where other bee keepers are around. Although it takes some time….apparently. Now, the situation is very comparable, from the view point of mite number. And I want to follow up, whats happening more closely (I check every week).
        On the other hand, reinvasion could take place anyway and secondly, to keep the selection pressure high (off course not too high), should be not that bad and even help the hive to come along with substantial challenges and sharpen resistance traits.

        • August 30, 2016 at 20:50

          Ok Rüdiger. It’s not too early for this colony. Very interesting to follow what happens. The colony probably didn’t get better genes, but stabilized epigenetic changes of their enough good genes, involving learning how to rid themselves of mites. Another matter I have to write something about is that healthy bees that live among other bees successfully probably don’t rob.

  • September 2, 2016 at 11:17

    Hi Erik, Rüdiger, Bartek and all…

    Very interesting thread and thanks for your thoughts, Erik, on epigenetic behavior.

    So far in my apiaries I see no DWV. I`ve got one hive carniolans which is infested, I see mites on bees (-20 mites in this hive) but no disease. The hive thrives.
    I see what looks like grooming in every day on the entrance board of this colony. I first thought it was robbery, but after being treated by 2-3 bees for some 5 minutes, the “victims” just walk in or relax on the boards. Robbers are carried away or leave.
    I filmed this and will send the link to you via e-mail.

    My new neighbors primorski bees are inside my hives now and included. They are smaller than my small cell bees.

    I have a new contact who is an experienced treatment free beekeeper in switzerland. He mentors new tf beginners. His method is to put a swarm made from treated bees into his apiary next to his tf bees. For some years now the treated bees learn from his drifting bees the mite defense in no time. After this period he gives them back and the people have mite resistant stock to start with.

    He is very interested in you, but has no english and no e-mail.
    I will translate for him.

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