Reworked website with new info

Hello dear beekeepers!

I’ve been reworking my old website. not my blogs. The English part became ready enough to be published and I launched it on http://elgon.es

elgon-website

There are quite some new material there. In the article “Resistance breeding” some of the experiences from 2016, very positive and quite important experiences. On that topic there will be more info later on.

This website is so called responsive, which most are these days. It means that it automatically adapt to different screen sizes, down to that of a cell phone. It’s made with and easy working and free app called Rocket Cake.

Keeping track of the infestation level

In the search for breeders for this season I tested a number of hives for the infestation level of Varroa mites in the beginning of May. Those choosen had not been treated for mites either not at all last season, or very little with thymol in the spring last year after showing an odd wingless bee. This was before the time of the Beeshaker with me. Better hade been to use the Beeshaker before using thymol to really know the infestation level.

I used the Beeshaker (more info about it and how to use it: http://www.elgon.es/diary/?cat=85). There were colonies with 0 mites from somewhat more than 300 bees. The best of those I use as breeders this year.

I also gave a number of colonies a thin tray with a coarse mesh that bees couldn’t pass hrough. High enough from the bottom of the tray so the bees couldn’t clean the tray. It covered almost the entire bottom. The purpose was to collect natural downfall of mites over a period of time.

I send some queens abroad and the Board of agriculture wants to be sure I have no tropilaelaps mites and no small hive beetles. (Both of those two pests have not been found in Sweden, tropilaelaps not even in Europe, the small hive beetle only in Italy.) Three weeks before the veterinary and the bee inspector came to visit for checking my bees I inserted these thin trays. Of course the inspector and vet also checked for American foul brood.

Varroagaller Varroa trays for checking natural downfall of mites. The one to the left without mesh cover.

Two of those hives I had checked with the Beeshaker got a tray. Three weeks later one of them had 7 mites on the tray. The other had 8. The bee shaker had given 1 mite each for these two hives.

1 mite per 300 bees is 0.3% infestation level on the bees (not counting the mites in the brood, those are usually at least the double amount).

Let’s say I missed 2-3 mites of the natural downfall. That would then be 10 mites in let’s say 20 days for easy math. That gives 0.5 mite per day. It’s been said that natural downfall per day during the brood season multiplied by 120 gives about the total number of mites in the colony. That would make 60 mites in total in those two colonies. The number of bees in those colonies were more than 30,000 each. But let’s say it was 30,000. If we divide 60 by 30,000 we get an infestation level of 0.2%. This level is though including the mites that had been in the brood during these 20 days, so the figure is not directly comparable with the 0.3% to confirm that the two methods give about the same result. The estimation of multiplying with 120 and other uncertainties makes comparison and/or the methods not exact anyway.

Does this comparison give an indication that these methods are good enough for checking the varroa infestation? Both methods have been used by others to decide when to treat or as a selection help for varroa resistance.

When the infestation level is so low as given above, it’s not possible to check the VSH trait either, as you will find too few pupae with mites. You can ask yourself if it’s at all necessary to test for mites anymore. I agree. But all my hives are not as good as these and reinfestation occurs. So I think I have to keep track in some way. Not in first place I think to find the best ones, but to find the ones with most varroa so I can protect the others from reinfestation.

The perfect resistant colony is of course such a one that is not very much affected by reinfestation, not letting in bees with mites on them for example. I will test colonies in August as well and I will check the hard boards in front of the hives for crippled wing bees or grey young bees crawling around as indications for viruses following to high varroa infestation.

The bee shaker and varroa resistance

Skak botten 2lc One mite from 300 bees.

I understand that sometimes it’s a good idea to get an idea of the infestation level of varroa mites in bee colonies. You can take samples from a couple of colonies in an apiary to get an idea when to treat. But my first concern is breeding varroa resistant bees.

I have never monitored the varroa infestation level in my colonies. I haven’t had time and I haven’t found any reason for it because I thought I had found a good compromise – treating with Thymol when I saw wingless bees on the hardboard in front of the hive entrance, checking every 10 days or so.

 

Good results up till now

I give a colony one or two pieces of dish wash cloth containing 5 grams of Thymol each when I see wingless bees crawling on the hard board in front of the hive. But this means I don’t treat every colony at the same time (hopefully some not at all in a season). This results in some colonies with higher mite loads not showing wingless bees yet. So these colony (-ies) will through reinvasion increase mite levels again quite quickly in those colonies recently treated.

But this way I’ve been able to develop more and more resistant bees and still produce a good crop. There have been a number of bees not producing any honey. Winter losses have been reduced from 30 % to 10-15 % (except the first year with varroa trouble when I lost 50 %).

The bees have been better chasing mites and remove infested brood. I’ve got good reports from for example Poland and Germany of low populations of varroa in colonies headed by Elgon queens, compared to other bees. And the VSH trait is becoming better and better. Daughters of my colony with the highest VSH % (80) gave colonies that in Poland dropped 2-5 mites after effective treatment while other colonies dropped more than 1000.

 

Thymol is useful but hinders total adaptation

I now have been aware that by having this regime I have a constant quite high varroa population in the apiaries as a whole, and thus probably a climbing virus pressure. In a way this is good as selection is done also on virus resistance.

How do I know that? Now when I’ve used the bee shaker somewhat this year I’ve seen that colonies may show wingless bees (DWV-virus) at low mite infestation. Such low infestation you didn’t expect them to do so, sometimes even as low as 2 % infestation (a daughter from a colony with high VSH trait [80%]! This experience and others similar, raise the question if very high VSH comes with higher susceptibility to viruses.). Wingless bees at 2 % infestation is totally different from a report I’ve got from a test further down in Europe. (There they normally treat effectively every year.) In that test where they didn’t treat at all, my bees didn’t show any wingless bees at 35% infestation while other bees had a lot.

 

How to explain the high infestation level in the test

Now I have to try to explain why my good bees could arrive at 35 % mite infestation. This is interesting and brings up another topic as well. The importance of memories of the worker bees (their knowledge how to chase mites), not only their genetics (and epigenetic history). My queens in this test down in Europe were introduced to bees that had not been selected the same way as mine, and those bees had been treated effectively every year. The bees could probably not chase mites as well as mine.

But of course the genetics from my queens would more and more influence the workers to build up a better behavior when it comes to chasing mites. When the bees have arrived at a good mite chasing mood they learn new bees born in the colony what they have achieved, more than what just come directly with the genetics. In Norway with Terje Reinertsen and Hans-Otto Johnsen experiences are achieved pointing strongly to this.

In an apiary where many colonies are non-resistant as in this European test, you get a mixture of all bees in the apiary through drifting and robbing. This is taking place more and more when the mite populations in the colonies rise. As it did in this test as the colonies were not treated at all.

In a situation when colonies are receiving a lot of mites from neighboring colonies, even the very best kind of mite chasing behavior is maybe not enough to keep mite levels low.

In the test apiary previous to this test, effective treating every year had kept the mite and virus levels low, so the mite population could grow much in the test without showing wingless bees – like in the beginning when the mite first arrives to an area. Then the virus levels are usually very low and there could be 10 000 mites and more in a colony without any signs of viruses (documented case in Sweden in 1987 when the mites were first detected on the island Gotland in the Baltic).

The bees in this test were on 5.5 mm cell size, while my bees are kept on 4.9 mm.

 

Also Thymol hinders total adaptation

I have talked to some beekeepers whose bees are totally treatment free since many years (Hans-Otto Johnsen in Norway, Richard Reid in Virginia and Myron Kropf in Arkansas). Their bees have now small populations of mites and are showing no wingless bees.

I have come to realize that also Thymol is a chemical that hinders the bees to fully adapt to handling the mites successfully on their own. It is in first place the epigenetic adaptation I have come to think of that is disturbed when alien chemicals (like miticides of all kinds) are present. Epigenetic changes take place when a chemical change occur due to environmental changes, like for example the presence of the mite. (But it should be said also that if you use Thymol regularly spring and late summer in a system not selecting better bees like I do, winter losses can be kept low. I know because beekeeper friends do like this.) Also Thymol like other miticides is lowering the immune system of the bees.

How do I then integrate these insights to go further in becoming totally treatment free?

 

A new strategy to try

I’m planning a new strategy, at least to start with in one quite isolated apiary. I have to stop using Thymol. First though I think I have to knock down the mites effectively to reduce the virus level. And then get a better control of the number of mites and take action without any chemicals if varroa populations are rising too much in colonies.

 

The role of the bee shaker

Here the bee shaker will play a role. And I have looked more into how Randy Oliver uses it. It’s much easier to shake a frame of bees into a bowl or pan and then with a measuring cup scope somewhat more than a deciliter (3.5 oz) of bees and pour them into one half of the bee shaker, half filled with alcohol (for example methylated spirit or rubbing[isopropyl] alcohol). Then screw it together and shake for a minute before reading the result. Compared to holding the bee shaker close to a frame side with bees and pour bees into it moving it slowly upwards, the alternative of Randy Oliver is quicker (at least for me). The next step is to test the VSH trait in the best colonies.

Skak yngelrum Start checking from one side in the uppermost box with brood. The queen hopefully will run to the brood if she is outside the brood area (probably not). The comb closest to brood you check so the queen is not there. 

Skak deciliter Shake the bees into a pan or bowl. Scope up somewhat more than a deciliter of bees (3.5 oz)

Skakburk sprit Pour the bees into one of the halfs of the bee shaker, which is half filled with alcohol. Screw the other half tight on top. Shake it for a minute.

Skak botten1lc Turn the shaker upside down and continue shaking until all the alcohol has poured down. Lift it up against the sky and count the mites. This colony had 14 mites on 300 mites and it got two pieces with 5 gram Thymol each. It showed no wingless bees.

What I hated to do

So what I’ve done so far is something I hated to do. In one quite isolated apiary I used an effective chemical miticide (only this time I promised myself) in August 2015. I wanted to use something else than Thymol to give the bees a break from that chemical. And I wanted to knock down the mite population effectively to lower the virus pressure in the apiary. I collected the knocked down mites. (In the rest of the apiaries I plan at the moment to continue as before.) The colonies that had needed most Thymol earlier in the season had the highest downfall of mites. They got probably continuously reinfested from other colonies that happened to not show wingless bees while they anyway had quite high mite loads. The defense system of these quickly reinfested colonies was probably lowered by Thymol, which made this relatively quick reinfestation possible.

One colony that hadn’t needed any Thymol at all (and very little the year before) and still had given me 80 kg (175 lb) of honey with 20 kg (45 lb) left for winter dropped less than 200 mites. And this happened in this very bad season of 2015. This colony is of course a breeder for the coming season.

 

The new strategy

Next year I will in this new strategy apiary make splits from the best colonies and place them in the same apiary (or if the number is enough there, place in other apiaries). In the least good colonies in this apiary (those with highest infestation level) I will kill the queen and give them a ripe queen cell bred from a good colony in this apiary. I check the number of varroa (infestation level) with the bee shaker twice a season in all colonies in this apiary. Each time it will take about 5 minutes per colony. And I look for eventual wingless bees on the hard board in front of the entrances. Before the number of mites rise too high (whatever that is), or when I see wingless bees, I plan to remove all capped brood (worker and drone brood) once or twice with a week in between. I haven’t decided what to do with those brood frames yet. Any suggestion?

 

 

Changes again

I ended the last blog-post saying that the season wasn’t completely over yet. That was very true. August has been our summer here in Sweden. And it’s not over yet, August and warm summer. Though the nights are chilly. But my wife and I are taking our daily morning swim in a near by lake, followed by breakfast at the shore, coffee and a sandwich.

Bigård23ljung Heather

Heather (Caluna vulgaris) yields honey this year in big parts of Sweden. In my area very good, even in areas quite far from places with lots of the plant. But in spite of this the total honey crop is the worst since I became a beekeeper 40 years ago.

But the colonies have changed appearance. Now they look very healthy and the winter room will be quite full of honey, not only from heather (a quite tough honey for wintering a long winter confined to the hive), but also from thistles, fireweed and golderod. And probably I will not use more Thymol than last year after all.

Why the VSH 80-daugter I mentioned in the former post had so much bald brood, I saw the other day, may well be due to a failing queen. She is not laying that much eggs any more. So there are fewer open brood for the mites to invade and thus not so many new healthy pupae that turns into new bees. And the strength of the colony declines. It’s a little late for the bees to shift the queen. They should have done that earlier. We’ll see if the colony will make it through winter.

Bigård23A Apiary where all supers above the queen excluder has been harvested. Most colonies are wintered on three square (12-frame) shallow langstroth boxes. Two colonies are wintered on two boxes Even with isolation dummy frames at the sides in both boxes). They are weaker than the others.

Bigård23B The strongest colony in this apiary

Bigård23C One colony in this colony needed Thymol against varroa now. The sign for me was wingless crawling bees on the hardboard outside the entrance. It got two pieces of dishcloth with 4-5 gram Thymol each (hopefully it will be enough, will check for this sign again in 10-14 days).

At the moment I’m harvesting all supers above the queen excluder. From some apiaries there is a quite good late harvest. From others not so good. But the winter room will contain a good amount of honey. Those colonies needing Thymol strips get it, not so many now. Most of the needy have got it earlier in the season.

Changing plans

I make notes. I’m sure you do to. How much is a good question. I made more notes as a beginner and quite some years after that. When I got well above hundred hives I began to question each kind of note and how much I could benefit from it. I wanted to save time, if I found it possible to skip doing some kind of notes.

For each year I use a fork binder. First I have a graph paper. On a horizontal line high up all the apiaries are numbered. On a vertical line to the left I make a note of the date, then an X for the apiary I have gone through that day. That’s the most important note, to be sure I don’t forget any apiary and to make sure it doesn’t take too long between my visits.

Fork Binder A spread in my fork binder.

I have made a map in the computer in the Excel application showing each apiary. On the spread is the map to the left. On the opposite side a blank graph paper for making notes. In the very early season (still winter/spring) I make note of the colony strength, how many “comb gaps” the bees occupy. Then of the progress of the colony (putting on boxes). At the end of the season, very late autumn/winter, again how many comb gaps the bees occupy.

I only make a thorough check of a colony if it doesn’t develop as expected. I check for eventual disease, if it has brood (thus a laying queen), and eventual other things to observe. I make notes only of things that depart from the average or the normal. No notes for a colony indicates an average or a normally functioning colony. Also notes are made concerning hot temper, no brood, wingless bees. I make notes of how much thymol in grams a colony get and what date, estimated amount of honey taken in kilograms (it doesn’t matter if I do a wrong estimation with 10-20%, the estimation is for comparison between the colonies).

When the season is over I compile the notes and do stats. Then I make a first probable selection concerning next year’s breeders and which queens I will shift next year. The final selections are made during May and June the coming season. Here the notes are invaluable as I tend to forget some colonies that I discover again when I’ve done the stats.

Before May comes there’s often a hard winter ahead, and a tough spring. And the spring this year was really tough, which changed the preliminary plans a lot. But the winter had been mild.

The spring was very rainy and very chilly. May was the coldest since 1962 in Sweden. The bees had small opportunities to get enough of fresh pollen for their usually quick buildup. And proteins they need desperately for everything for their rapidly expanding colony to function properly.

My bees have a higher varroa pressure than most others maybe, to let the least good colonies reveal themselves. Due to the season the immune system (rather defense system as their defense against diseases are different compared to mammals) among other things didn’t work fully due to lack of proteins. Viruses showed up even if the varroa population wasn’t big.

Maybe I should have stayed cool and not used varroa treatment, I don’t know. Varroa treatment affect the bees negatively as well, but of course not as much as mites. When should I stop treating altogether? And how should I do it? Just stop at any moment or do it in a certain way? I don’t know.

I have used more thymol this season than last. The colonies with high VSH value (VSH 80% the best one, included) and their daughters, most of them, showed wingless bees and many dwindled. I was surprised and disappointed. How was this possible? Can high VSH-value mean less good other traits than VSH? Sometimes such phenomena can appear with strong selection for strengthening a trait, as such selection often is made with the help of inbreeding.

Anyway, when I should decide which queens to breed from I went through the notes and found some interesting colonies I hadn’t payed enough attention to. Those colonies hadn’t needed any treatment for two years. So I made a VSH test. The S241 colony had three mites of 103 pupae checked. Two of the mites had no offspring. The third had one white daughter mite and no male. The H101 had one mite of 110 pupae checked, with no offspring. The neighbor colonies of these two colonies had wingless bees and many were dwindling. Of course I bred from these two good colonies.

Quite soon afterwards the H101 showed a wingless bee. I had split that colony and put the big split with the queen in the same apiary as the “mother” colony. The split with the queen lost most of its field bees that way. Was that a cause?

The S241-split was moved to the home apiary and kept its field bees. The split grew fine and is now a big colony. All the daughters are doing fine and building fine colonies. Both S241 and H101 are colonies that have shifted their queens themselves, whatever impact that may have.

To sum it up. I had to change my breeding plans quite a bit for this year, after this unusually cold and rainy spring. But I think it’s important to make good notes and from them plan for next season. Then when next season comes you know what to change and how.

The VSH 80%-colony was a disappointment and I don’t understand that, yet. There are though a couple of daughters from it that are very interesting. Those havn’t needed any treatment and didn’t show any wingless bees. One has shifted it’s queen. The second are showing a lot of bald brood and spotty brood (cleaned out brood with mites?). The queen is laying well. It seems it’s fighting reinvasion of mites and doing it well. So good that the colony hasn’t grown and hasn’t given any honey.

Bald brood One of the daughter colonies to the VSH 80-colony is fighting hard against the mites and havn’t shown any wingless bees, not yet anyway. Maybe a breeder next year.

This season is a disaster. The month of July has been the rainiest I have experienced ever. The honey crop is in average maybe 5-10 kg per hive (including winter losses and failing colonies) to compare with 25-35 kg for several years. And many colonies may need a good sugar feed to survive the coming winter.

But, the season isn’t completely over yet…

 

 

Aiming for a new season

In the beginning of March the bees had their main cleansing flight after winter. In the beginning of April most of them had more combs and boxes given. At the end of April another round checking food, need for thymol, collecting some dead outs and putting on supers took place.

Previous years winter losses were about 15 % with another 30 % were saved through thymol and queens shifted (no or little crop), This is the investment price for developing a more varroa resistant stock. I give some thymol when I see wingless bees.

Last year winterlosses were about 10 %. This winter losses are also about 10 %. A good development is that only another 10 % are saved with thymol and will have their queens shifted later. Also breeders have been treatmentfree longer and VSH value for the breeders are better. And bees are putting more honey closer to the broodnest for winter storage, thus there is more honey for winter food. The bees are shutting down brood already in August and waiting till January or February before starting again. Thus they use less food in winter and save it for brood when starting the new season, which is started even somewhat before the main cleansing flight. The bees know what’s coming.

Most colonies got a super above queen excluder in late April and those splits wintering on two boxes their third brood box. And those 10 % fighting varroa and virus and/or something else maybe a few drawn empty frames, some food frames and maybe a piece of dish cloth with thymol (4-5 gram).

Bästa samhället 2015-04w

The best colony so far

The best colony in April was the best producer last year, didn’t need any thymol last year, didn’t swarm and has a very good temper. It was wintered with 20 kg (44 pound) honey and 10 kg (22 pound) of sucrose sugar.

In beginning of April it had about 10 kg of food left and was full of bees. For safety reasons so the queen shouldn’t stop laying, it got a frame of food in the super from the storage.

In late April this box above the excluder was half full with willow honey and full of bees. So the colony got another super. I plan to check the infestation rate with the bee shaker (http://www.elgon.es/diary/?p=660) soon and also the VSH value (http://www.elgon.es/diary/?p=146). Of course I have to breed from it.

 

Jante and The Involuntary Adviser

“It is better to listen to a string, which burst,
than never to span an arc.”
Verner von Heidenstam (Swedish poet), 1902, Invocation and Pledge

 

Jante verbalize the unwritten law that says that you can not stand up and think that you are better than others in some way. It’s a fictional law of a fictional Danish town in a novel by Aksel Sandemose in the book En flykting korsar sitt spår (A refugee crosses his tracks) (1933). The closest phenomenon in the English-speaking world is what is called The tall poppy syndrome.

 Jante
1  You shall not think you are something.
2  You shall not think you’re as good as we are.
3  You shall not think that you are wiser than we are.
4  You shall not fool yourself into thinking you’re better than us.
5  You shall not think that you know more than we do.
6  You shall not think that you are more important than we are.
7  You shall not think that you are good at anything.
8  You shall not laugh at us.
9  You shall not think that someone cares about you.
10 You shall not think that you can learn us anything.
Jante Criminal Code
11 Don’t you think we know something about you?

 

Commitment
Commitment can be dangerous as it can lead to knowledge that leads to the development leading to change. If those in charge do not control the course of events. They need control of change not to risk losing control of the situation – losing control over others, over money, over development. If you have influence and power you may want to keep it. That’s when you oppose those who get involved – rather than encourage, assist and perhaps cooperate.

 

Do nothing
If you don’t do anything you don’t risk standing out and you don’t risk falling into disfavor with those who want to have control. But you can never do anything good, increase knowledge and contribute to development.

 

Do something
If you do something you risk making mistakes. A mistake, may learn you important things. And you can get ideas about how to do instead. If you do something good and it’s new, you learn something new, and also others do that, perhaps leading development forward.

 

 

2008, varroa and viruses

In spring of 2008, I had been told not to give advice to beekeepers how to combat the varroa mite. This is because I allegedly gave dangerous advice that caused beekeepers to lose their bees. The one who told me this, I had been told treated against Varroa mites only once a year trickling with oxalic acid solution in November and calculated to have 30% winter losses.

Shortly afterwards a desperate beekeeper called me in late April. He actually sought someone else he could not get through to. He asked for advice on how he would do to save his eight colonies from dying as they all showed wingless bees in different amounts. It is considered by some that a bee colony showing wingless bees is doomed to die and can not be saved. So what should I do? I was told not to give advice. But should I tell the person seeking help to let the bees die, or should I give the best advice I could? Deny a needy help, I could not.

– The mildest treatment against the already by viruses weakened bees, are probably in this case Apistan, I said, but you may not want to use that. (The mites had just arrived there and built a population and Apistan had never been used before.)

– No, said the beekeeper from east central Sweden.

– To treat these highly viruses weakened bees with acid is to lead them into death, I said. Oxalic acid could possibly have been used in November, but only really if one earlier in July/August had checked the colonies concerning the amount of mites and treated with something then if needed, so they are not weakened when Oxalic treatment comes in November/December.

– Do you know what Apiguard is? I asked.

– No, he replied, and did not know what Thymol was either.

– The best advice I can give you is to get in touch with Joel Svensson’s Bee Equipements and ask them to help you get Apiguard. Read the packaging how to use it, and apply it as soon as you can. Thymol, I think is mildest for the bees in this case.

In September the same year the beekeeper called med and thanked me for I had helped him. All his bee colonies had survived, even the most affected and vulnerable. He had also made a few splits and wintered 13 colonies.

I asked him how long time Apiguard was in the hives.

– All summer, he replied.

– Huh, I cried, but did you harvest any honey then?

– Oh yeah, was the answer.

– But didn’t the honey taste thymol, I asked.

– No, he replied.

Hmm, could it be possible? Maybe yes, maybe no. Well, you should not and need not to use Apiguard as this beekeeper did. But the most positive thing with this beekeeper was that the colonies recovered and lived. And the honey was safe to eat whether it tasted thymol or not. It was probably mostly this beekeeper and his family who ate the honey that year I believe. He certainly hadn’t a bumper crop.

The bees pollinated and did what they should. And the beekeeper was happy.

Oxalic side effects

Oxalic acid has been used for many years in Europe to kill Varroa mites in bee colonies. Recently it has been approved for use in USA.

Oxalic Trickling Photo: Anders Berg

When choosing between strategies against this mite it’s good to know all the pros and cons. Not much has been said about the negative aspects of this acid. In 2012 a study was published that hasn’t got much attention among researchers. I understand it’s why Dr Heike Ruff at Würzburgs university in Germany wrote a note about this study in the German bee magazine ADIZ no 2-2015, page 16.

The website Resistantbees.com made a reference to this and also made a summary of the study. http://resistantbees.com/blog/?page_id=2302#dt

If you succeed in using Oxalic acid correct it can help bees survive while they otherwise had died. But experiences from Sweden is that it’s difficult to have a number of years in a row with low winterlosses using Oxalic acid. If it’s only because of not successful tracking of the mite population and treating in summer when needed, not to get to high mite population when it’s time for Oxalic, I don’t know. Or treating when there’s still brood in the colony, quite useless. Or maybe damage has been adding up some years whch results in high losses with intervalls. Obviously there’s more to find out. This study cited below shows that. More beekeepers in Sweden are finding Thymol a better alternative, especially when used in spring (instead of Oxalic in winter) and after the main crop in late summer (instead of pesticide strips).

Best of all though is to work for resistant bees the best we can.

 

Sublethal effects of oxalic acid on Apis mellifera: changes in behavior and life expectancy. Oxalic acid treatment side effects
To combat the Varroa mite beekeepers can use different veterinary drugs, including organic acids such as formic acid or oxalic acid (OS). So far only the efficacy against the mite and how well the bees could tolerate the acid was evaluated for the approval of the OS. The criterion for how well the bees can withstand and tolerate the Oxalic acid is determined if the bees die (the mortality of the bees). Therefore the recommendation for treatment for Central Europe is to treat once in the broodfree time in late autumn with 3.5% sodium dihydrate OS. Higher concentrations or multiple treatments lead to high loss of bees. A study now shows that the OS-treatment, despite correct application can have harmful effects on bees. The acid affects both the performance and behavior. Treated workers neglected the brood and were inactive. Learning and memory performance for fragrances were reduced. Even the life of the bees were shortened. In addition, the acid can damage the digestive tract of the bee. Also, the bees clean frequently. Whether it is the desire of the bee, to get rid of adhering acid crystals on the body, or is a symptom of poisoning is unclear. Obviously, however, such weakened bees cannot contribute to the health of the colony. The exact effects of the OS are not known to the researchers. Further studies will show whether the effects of acid are caused by nerve damage (neurotoxicity).

 

The results of the study showed

  • That the treatment with OA led to a reduced lifespan.
  • That treated bees showed an increased self-grooming, a superior tendency to inactivity and decreased nursing behaviour….The increased self-grooming of the treated workers could be caused by the detected residues of OA on bee surface.
  • Treatment with a 3.5% solution of oxalic acid dehydrate (OA), corresponding to the dosage of 175 μg/bee, causes sublethal effects on A. mellifera. The decreased activity and nursing as well as the reduced lifespan of treated bees are aspects for a permanent damage due to the treatment with OA.
  • A decreased activity was also noticed in other studies where bees were numb for several hours (24–48 h) post application of 50 mL 4.2% oxalic acid per colony (Bacandritsos et al. 2007). Similar effects are known from bees treated with formic acid. Due to the fact that the animals did not recover from their immobility, permanent neurotoxic damage was assumed (Bolli et al. 1993). Concerning OA treatment comparable damage may have caused the decreased tasks performance in the colony, including nursing.
  • OA treatment affects the general condition of bee colonies: the workers’ performance is restrained due to the changes in behaviour, the decreased nursing of brood can lead to a lack of healthy and vital workers and the decreased lifespan could modify demographic alterations in colony age structure. Under the suggestion, that the treatment will cause damage of the digestive organs, such bees would be weaker and less vital. This could influence the general state of health of whole colonies.

 

References:

  1. Schneider, S., Eisenhardt, D., RADEMACHER, E., Sublethal effects of oxalic acid on Apis mellifera (Hymenoptera: Apidae): changes in behaviour and longevity, Apidologie, Springer Verlag (Germany), 2012, 43 (2), sid.218-225. https://hal.archives-ouvertes.fr/hal-01003525/document
  2. Ruff, Heike, Oxalsäurebehandlung mit Nebenwirkungen, ADIZ 2015; 70 (2), p.16.

Meeting the sun

The second Sunday in March the temperature, wind and sun, together with filled intestines of the bees that had produced the heat for the winter cluster took these bees out to meet the sun. The main cleansing flight took place. What a relief!

MötaSolen2

Most often in Sweden you reach well into March before the main cleansing flight takes place. Now the colony has been brooding for some time, and this accelerates now. If the colonies started to make brood too early, for example due to a warm spell in January, or if you have Italians that have a hard times taking a break in brooding, this last winter was hard at them as winter never really came until February for two weeks. Those colonies have produced many Varroa and filled their intestines early because they have used a lot of food. The immune system is thus weak. Virus, Nosema and chemical residues contribute to the risk of defecating inside the hive, if there are bees left there. Many may already have left just flying out away from the hive (due to virus) leaving it sometimes empty of bees.

This winter should have been easy for the bees due to its mildness. But for many beekeepers that have trusted oxalic acid in late autumn and drone brood cutting in beginning of season (and just that) to fight the mite, this winter has been a bad experience. For a couple of years this concept may have worked okey. And the beekeepers, perhaps beginners, have thought they are safe.

But last year the longer brood season together with no or little checking of the mite population in July/August (mite population should not be too high then when the winter bees are produced), the mite population was too high when oxalic acid treatment came in October. The weakened bees then were still more weakened by the acid and overwintering became still harder. And it became even harder as the bees still had brood when the oxalic were used. Most mites were in that brood (that of course had well developed virus population by now) and escaped the oxalic. So it’s easy to explain the winter losses of such hives.

Now a beekeeper named Bengt Haglund just north of Stockholm have used thymol gel (Apiguard) with 25 grams of thymol in the gel in one small tray in spring. Upside down directly on the top bars, just above the brood. Next treatment was directly after late summer harvest. Another tray of Apiguard with the opening upward this time, between the two brood boxes. Winterlosses for five years in average 1 % for Bengt.

My goal is treatment free. I’m close. To get there I have chosen to use small cells, breed for resistance and use good quality natural food as much as possible. On my way to this goal I made the conclusion that I was about to loose almost all my colonies when the Varroa arrived. Therefore I treated, reluctantly, and lost “only” 50 %. The only season I have lost that much, in 2008-09.

So I used Thymol. But I don’t use anything until I see wingless bees. The virus causing it is the most common associated with Varroa mites. And I use as little as possible. I’ve found a piece of dishcloth with 4 grams of soaked in thymol is enough to start with, on top of the top bars close to the brood. Every ten days another piece as long as I see crippled wings. Strong hives might get two pieces at a time. Most hives get it in spring and later just after harvest. If there is some smelling left in the boxes when I harvest, it stays in the wax actually, and in the woodenware. The honey does not get any extra flavor (if it should it’s not unhealthy at all). Thymol residues are finally ventilated away.

Yes, Thymol kills microbes. But sometimes it’s better to have dead microbes and live bees, than dead bees and with them dead microbes. And Thymol is much less dangerous for me than oxalic acid – when making the oxalic solution, when handling it, when handling eventual fumigation and when handling equipment with crystals when cleaning up dead colonies.

But again, the goal is treatment free. And I’m almost there. Last year many colonies didn’t need any Thymol. Many got only 4 grams. Another lot 8 grams, and 12, and 16. A few more, and up to 40 grams at the most. Those that got 16 and more will have their queens shifted this year.

Winter losses for me up till now is about 5 %. Still some more % will not make it until May I’m sure.

Most colonies look very fine. And it seems I have several fine breeders to use. I’m happy the investment in breeding for resistance pays.

Evaluation of season

Around Christmas I get time to do work on an Excel application on the computer, feeding it with new figures about the honeybee colonies from the season. It helps me identify the least good colonies (which will get their queens shifted coming season) and the best ones, which to breed from.

I focus on Varroa resistance, good honey crop, easy management, low defensiveness, low swarming tendency and keeping track of the motherline, so I can trace the heritage somewhat. Earlier, when I got the virgins mated on isolated mating places with drones from sisterqueen, I had nice pedigrees. Now when there are only Elgon bees (or almost) where the virgins mate I just make a note of the apiary where they got mated.

 

Focus on traits

A.  The evaluation of Varroa resistance is kind of a two-step stair:

  1. The Varroa population is allowed to grow until (or not) the colony shows one or more wingless bees, which I interpret as a sign of presence of Deformed Wing Virus (DWV). This virus is the most common in connection with Varroa. If so the colony gets one or two pieces of dishcloth with 4 grams of Thymol each. One piece usually if the colony is weaker, for example in spring (or a strong colony late in season that probably didn’t need it – just in case). If still DWV-bees 7-10 days later another piece(s), etc. This is done regardless if there are honey supers on the colony. But if harvest time is a week later I wait until then. Most Thymol is though given either before (in spring) or after nectar flow (late summer). Thymol goes mostly into wax and wooden parts and gets ventilated away again. Honey has never got any taste of thymol with me.
  2. When the breeder candidates have been identified – those that have been without thymol the longest and still have a honeycrop higher than average – I test those for VSH the coming season, if they have wintered and develop well. In 2014 I tested the breeders after I had used them due to lack of time. I want to do this in May before I choose which to graft from.

B.  The honey crop is compared between all relevant bee colonies. This is done with the help of a ranking list with estimated honey crops instead of the actual figures. That shouldn’t be correct due to different conditions in different apiaries/locations. This way it’s more correct even if it never will be exactly correct.

Consideration is taken to colony strength in spring (just after the main cleansing flight, late March/early April), crop size (including roughly how much honey is left with the bees), and if bees have been taken from the colony for making new colonies or mating nuces. Consideration is also taken to autumn strength after the season (in November after the old field bees have died). An average of the resulting theoretical honeycrops is calculated for each apiary for relevant colonies. Too weak colonies in spring or hives that have swarmed too much or is weakened too much of disease (virus from varroa mostly) are not included in the average. Then all averages for all apiaries are used to make an “selection average” for apiaries (for 2014 it was 91 kg – 200 lb). Then each apiary average is compared to this overall “selection average” and an adjustment is made, up or down for each apiary. Then a final calculated honey crop and a following grade is made for each colony and finally the ranking list.

Why I ended up with a 9-point scale (1–1.5–2–2.5–3–3.5–4–4.5–5) I don’t know. To be considered as a breeder I mostly want a colony to have at least 3.5 points, that is above average in honey production.

C.  I almost never use a queen that has swarmed. There must be a very good reason for doing so, for example trying the queen of the wall – http://www.elgon.es/diary/?p=505http://www.elgon.es/diary/?p=515 . If a daughter queen is not shifted by me in the leftover colony, she has to show herself worthy coming seasons, just like every other colony.

D.  I don’t want to use a defensive colony and very seldom do. I tried one in 2013. Actually one of her daughters is a breeder candidate for 2015, with good temper, but the average among her sisters is not good. But bad temper is actually one of the easiest traits to make better through selection.

 

Ranking list 2014

Let’s look at the ranking list for 2014. Most important is how many years the bees of a colony (and their relatives and ancestors in the same colony) have not got any Thymol. Sometimes in the history of the colony, a split may have been done early in the season before the mother colony got Thymol. This could have happened more than once. The best colonies come at the top of the ranking.

Thymol used in the previous season (2014) is zero grams for a colony considered as a breeder (2015). And this colony should not be a new colony of that year (2014), but a big colony that has wintered at least once with the present queen (maybe a new colony the year before, 2013) and produced a crop. 2014 is the first year I have colonies that havn’t tasted thymol for two years as big colonies (2013 and 2014).

Namnlista tymol14 etc.xls Click on the list to make it bigger and readable, then click on the back arrow in the upper left corner to get back to the text.

Among the top 11 on the ranking list, one is too defensive and 3 have queens born 2014. Two were breeders already in 2014. They may be good enough also for 2015 – H112 and H105.

Number 6 on the list is not considered for 2015, as the colony swarmed, but I keep an eye on it as it still produced a good crop. Maybe it can be considered for 2016. Number 7 has not a good temper and it’s queen is mated at the edge of the Elgon area with possible influence of non-Elgon heritage, but so what, if the traits are good, but temper is not in this case. But if I hadn’t had any other colonies… Number 9 is a split from H112 that made a queen of their own this year. Maybe a breeder 2016? Number 11 shifted its queen early in the season. Maybe a breeder 2016?

Number one on the list is the queen of the wall (see above). I have put the last year with thymol to 2008 for her, just to put a figure in the column. Probably those bees, well their ancestors, have never tasted any miticide at all. Now that colony may not be as resistant as the best of my other ones as they havn’t, living on their own, had any reinfestation, and they have got a brood cycle break every year (swarm) and have a smaller amount of brood due to a smaller nest than a big hive, so I will make just a few daughters. But they have to be hardy. Number 3 is considered as the bees (their ancestor bees and colony) tasted thymol as far back as 2011, though the crop grade is just average.

In 2014 the breeder colonies had been without thymol for one year (2013) as big colonies (and not two or more for the best considered for 2015). The best of such ones for 2015 are number 28, 29 and 30.

Now this season of 2014 I gave thymol when seeing just one single wingless bee outside a colony on the hardboard. Earlier seasons I waited till I saw at least two. And still earlier at least three. The threshold for giving thymol is getting lower to get a still better selection and a quicker improvement of the stock. It’s because of the improvement this lower threshold is possible. If you don’t have bees selected for Varroa resistance I guess just one single wingless bee is a tough enough threshold as such bees probably are not as quick in throwing out a bee with a lot of virus, as selected bees are. (Isn’t this kind of an contradiction in reasoning, eh?)

Had it been an earlier year, those that 2014 got 4 grams of thymol hadn’t probably got any thymol at all. If we look at the list with this in mind, number 50 and 51 would also be breeder candidates. No 50 was used in 2014 as a breeder, with as it seems good result.

 

Shift these queens

Almost all of those colonies that received 16 grams or more of Thymol ,will have their queens shifted in 2015. They are less than a third of all the colonies. These are the most important to identify. Some of them have though been very high producing. A colony that has not been selected for Varroa resistance is usually thought to need at least 50 grams of thymol a year. That corresponds to two trays of Apiguard. Those colonies that got new queens born in 2014 will of course not get their queens shifted in 2015.

Namnlista tymol14 etc.xls The bottom part of the ranking.

Spring will show how good the colonies have come through the winter and if they develop well without any need for thymol. Coming May (2015) I will most probably test more colonies concerning their VSH value than in 2014.