Bee Culture – May, 2005
Überleben eines Profiimkers in Norwegen
Testergebnis: kleinzellige Bienen bringen mehr Honig – Varroapopulation ist in kleinzelligen Bienenstöcken deutlich geringer.
- Ich bin nicht ein Imker dem es nur darum geht mit Honig Geschäft zu machen. Im Leben geht es um mehr als um Geld, es geht um eine gute Lebensqualität. Ein solches Leben erfordert eine gute Qualität der Lebensmittel.
- Mein Fokus liegt auf biotechnischen Methoden, selektiver Zucht für varroaresistente Bienen und einem Management-System, das den Bienen hilfreich ist zu überleben und zu produzieren.
- Im Herbst 2004 überwinterte ich 650 Kolonien.
- Eine wesentlicher Teil meiner Imkerei ist es den Bienen zu helfen, so natürlich wie möglich zu leben.
- Test zur Zellgröße 2002-2004 – Vergleich kleinzelliger Stöcke mit konventionellen großzelligen Stöcken.
Im Jahr 2002 baute ich einen Testbienenstand zum Testen kleiner Zellgröße auf.
Das Ziel des Tests war es, die Entwicklung der Varroapopulation während des Tests zu messen und die Honigproduktion zu messen.
Ergebnisse im Jahr 2004
– Die Milbenpopulation war in der gesamten Saison 2004 in der kleinen Zellgruppe deutlich geringer.
– Die kleine Zellengruppe war im Schnitt um eine Zarge stärker zum Trachthöhepunkt im Sommer. Die durchschnittliche Honigernte in der großen Zellgruppe betrug 36 kg. In der kleinen Zellengruppe war sie um 24% größer mit 44,5 kg.
– Eine interessante Beobachtung war, dass die Honigernte bei den kleinzelligen Stöcken gleichmäßiger als bei den großzelligen war, neben dem besten Stock und einigen wenigen schwachen.
- Letztendlich habe ich nicht herausfinden können, daß die kleinen Zellen irgendeinen negativen Einfluß auf die Leistung des Bienenvolkes haben
survival of a comercial beekeeper in Norway
Scandinavia is dominated by hobby beekeepers and hobby beekeeping. There are though those that make their living on bees also here. Most of these survive with the help of making money also in other areas than beekeeping. But there are still some that live only with the help of their bees.
I’m not just a beekeeper that wants to make money on honey. Life is more than money, it’s a good quality life. Such a life requires good quality food. Natural food from the bee hive is outstanding in many respects and has the potential of adding many good properties in a health giving food supply. Scandinavia is lucky as we live in a very little polluted area of the world and thus we have good possibilities of producing residue free food. This is though challenged for example by the Varroa mite.
The beekeeper takes the consequences
As a producer and beekeeper you are dependent on your own decisions, even if there exist many regulations and much advise of different kind. Scientists try to be correct in a way that meets a scientific standard (which is well understandable). Therefore they often have difficulties in giving answers that they can’t stand for with 100% certainty. This may create uncertainty among the practicing beekeepers. Which of course also anecdotal experiences of fellow beekeepers may do. For a commercial beekeeper all this may put him in a not so easy position. With all information he can get, scientific reports, anecdotal stories and his own observations, it is the beekeeper himself that will make the decision how to design his beekeeping management. It is he, not his advisers, that will have to take the consequences. These will finally show themselves in his bank account!
How we fight the mite
In Norway where I live you are not allowed to use what is called pesticides against pests. To fight the Varroa mite we are ordained biotechnical methods and organic acids. The purpose is to keep the bee colonies and bee products free from residues and not to produce a multi resistant mite. Not only pesticides though, but also acids have their drawbacks. The biggest is withholding the long term solution of mite resistant bees.
Additionally you do things to the bees that influence their health when you pour foreign substances and high concentrations of otherwise innocent stuff into the bee colony. All these act as poisons. We seem not to know much about how these substances influence the bee colony other than kill a lot of mites, but not all.
My focus is on biotechnical methods, selective breeding for mite resistant bees and a management system that helps the bees to survive and produce.
I saw the first Varroa mite in my operation in 1997. I tried different methods available, but soon came to use only what is contained in my description further down.
I wintered 650 colonies in the autumn of 2004. Due to my experiences the last years I expect 5-7% winterloss, about 40 colonies. Then in spring, for a number of different reasons, around 100 colonies will have a too slow development. Most of these are old production colonies. Varroa, nosema, chalk brood, failing queens and “just slow” are some of the reasons These 100 weak ones will end up as 30 colonies after uniting them in different ways. Those united units will give a crop. This makes an additional loss of 60 colonies. Of course these united colonies will have a new queen eventually. But this early in season we don’t have new laying queens in Norway. These united, somewhat affected colonies of different ailments are moved to an apiary of their own so that they will not influence the other colonies.
In June at the earliest, when I have new laying queens, I make my main number of new colonies. Most of them could be described as artificial swarms. The goal is to have about 200-250 new colonies going into winter. If I succeed in making 250 colonies that all survive and no additional colonies of the old ones fail, I will increase the number of colonies by 150. But this will not be the case as some additional ones will fail of the old for different reasons, and some of the new ones will fail. Hopefully I will increase somewhat.
Artificial swarms and splits
The artificial swarms are made without brood frames and only with new foundation and a new laying queen. They are placed in a new apiary of their own with no old colonies. Now they just have to grow until autumn and be wintered. They will make good production colonies next season.
Some of the new colonies will be made later in the season due to a lack of newly mated queens. As you may understand I have to adjust to a very short and intense season and have to be somewhat flexible due to circumstances. Some new colonies will get a ripe queen cell, not a laying queen.
New colonies which I make later in season will have a number of brood frames, more the later they are done. It’s all about availability of queens how many of each type of new colonies are made. We don’t have easy to get big batches of new laying queens in Norway. Especially not of the breed I work with.
Those production colonies that survive well for a couple of seasons, give good crops and are satisfactory in different respects will be those among which I choose my breeders.
My aim is to let my new queens mate under satisfactory controlled circumstances. I sometimes use an isolated island. Many times I use an apiary, fairly isolated, in an area dominated by my good bees. To this apiary I move selected drone colonies, which could have sister queens, or they could have queens of different mother origin.
The breed I use is called Elgon and has its origin in Sweden with Erik Österlund, the editor of the Swedish Beekeeping journal “Bitidningen”. This breed is a mix between mainly the Buckfast bee and the east African mountain bee Apis mellifera monticola. It’s bred with the purpose of surviving of its own in spite of the presence of the Varroa mite¹.
But sometimes I buy an apiary due to its good site, including a number of colonies. There are also always colonies that make supersedure queens, sometimes when they have been moved to the heather in late summer. Many times they are then standing close to apiaries with other types of bees. And I haven’t succeeded in shifting to only Elgon stock to begin with either. So I will have a certain amount of different stock in many of my apiaries. About 80% is though of mainly Elgon heritage.
Management system necessary
My anecdotal observations tell me Elgon stock is more resistant. Small cell size gives more resistant bee. Test results and my own experiences tell me that. But resistance vary, all colonies are not Elgon and all beekeepers in the neighbourhood do not have Elgons or small cell size. This creates a higher mite pressure, especially maybe when the bees are moved for the Heather flow in late summer. This makes a management system necessary that can take care of differing mite pressures.
One essential part in my beekeeping is to help the bees to live as natural as possible. Totally natural is impossible for modern beekeepers. You can’t for example keep bees in stocks and have just a few in every apiary. One essential part in a natural context is the wax. In nature bees move around, leave old wax and make new. Bees swarm, mother colonies die. Wax is left to others. That’s why I work with artificial swarms moved to new locations and let the bees draw a lot of new combs.
A compromise that helps is wax foundation. Natural cell sizes vary², sometimes little, sometimes more. The smallest ones are in the brood area and the biggest in honey storage area.3 Therefore I today mainly use 4.9 mm cell size in brood area. But I still have colonies with 5.1 mm cell size in brood area. As I use queen excluders above the brood boxes I use my enlarged cell sized combs of 5.5 mm cell size in my honey supers.
Cell size is not the only aspect constituting the amazing structure that the bee comb is. The fairly good regularity of the six sided cell and how the cell bottoms are formed are others. To mimic nature as much as possible the cell bottom can’t be flat. It consists of three rhombs at certain, quite deep angels. And naturally built cells are many times much more regular than the imprints in the wax foundation we buy. I think of wax foundation often being stretched when milled. In what aspects this influence the bee colony we don’t know. Can we assume that this lack of knowledge give us reason to believe that the influence is of little importance?
Quality wax foundation
I have been a lot occupied trying to produce good quality wax foundation. Because of the big quality variations of the wax foundations on the market in Europe I went to USA to buy machines and create a production line of myself. The problems in Europe are the stretching of wax foundation during milling and centering of the embossing rollers so that the bottoms of the cells on opposite sides of the foundation are misplaced. In addition the cell bottom rhombs are meeting each other at a too small angel creating a too flat bottom. Of commercial available equipment the one that come closest to what I want was from the Hawley Honey Company in Iola, Kansas.
My biotechnical methods
The biotechnical methods I use to fight the Varroa mite are the following.
1. I make artificial swarms, which are put in apiaries of their own to avoid reinfestation.
2. In summer if I come across colonies that seem to have mite problems, I take a lot of bees from those to make artificial swarms (and some from weaker colonies, thus leaving the good producing colonies to give me a big crop). Thus the mite population growth is broken in those colonies as the brood will be small due to fewer bees, and any later influence from them is hindered. Later in season the queen is shifted. You may argue that the new colonies will have too many mites this way. But the new colonies will have small mite population growth too due to being small in size. They in addition get queens from mothers selected for mite resistance. My experience is that this works well enough.
3. I use a breed with resistance traits, which I further select.
4. All colonies are supplied with screened bottom boards.
5. I use natural (and not enlarged) cell size, at least in brood area.
6. Those odd colonies that seem to develop an alarming level of mites at the same time as colony strength is decreasing more than average, are terminated. The reason for this is to avoid eventual negative influence on the others.
Cell size test 2002-2004
In 2002 I established a test apiary for testing small cell size. There were two groups of bee colonies in the test apiary. The two groups were placed as far away as possible in the apiary, but still close enough so that they together could be called an apiary.
The goal of the test was to measure the development of the Varroa population during the test and to measure the honey production.
One group in the apiary had enlarged cell size (which have been “normal” for many years) in the brood area (5.5 mm – 55 mm measured over the parallel sides of ten cells). The other group was established on bees born in 5.1 mm cells. The following year (2003) cell size was worked down to 4.9 mm in the small cell size group.
All queens in the test apiary were sisters bred from the same colony. And they were all mated at the same isolated mating station with sister queens producing the drones. The breed was Buckfast.
I started with 20 colonies in each group, with the two groups 200 meters apart to avoid robbing and drifting between the groups. To further avoid unwanted influence harvest was done late in the day, escape boards were used and entrances were reduced.
Late in autumn 2002 when there was no brood, the test colonies were treated with oxalic acid. The aim of this treatment was to even out the mite population and start with a low amount of mites.
The small cell colonies at first did not draw the 4.9-foundation well. Uneven cell sizes appeared though quite some patches were of good appearance. The least good drawn combs were replaced as soon as possible with new 4.9 foundation and the bees drew them better and better.
When the small cell group was given new foundation, the big cell group also was given new foundation (then of course of 5.5 mm cell size). Because of the given circumstances just a few measurements were made in 2003. An alcohol wash in October when no brood was at hand showed a lower amount of mites among the small cell colonies.
Results in 2004
The mite population was throughout the season in 2004 significantly lower in the small cell group. The natural downfall in average in the small cell group peaked with 2 mites per day and then decreased steadily. In the big cell group it peaked at 7 mites a day, decreased and then increased again.
An alcohol wash was made in autumn when no brood was present in the colonies. In the small cell group mites per 100 bees (%) was 14 (the range was 3-26%), and in the big cell group 29% (the range was 3-64%). The 3% colony in the small cell group gave an average crop, while the one with 3% in the big cell group gave a very small crop telling us it was a weak colony, which it was. The three 26% colonies in the small cell group and the 64% colony in the big cell group all gave good crops indicating strong colonies with good opportunities for the mite to reproduce.
The small cell group of colonies averaged about one box stronger at peak strength in the middle of Summer. The average honey crop in the big cell group was 36 kg (79.2 lbs.), range 8-57 kg (17.6 – 125.4 lbs.). In the small cell group it was 24% bigger with 44,5 kg, range 23-62 kg. An interesting observation was that the honey crop from the small cell colonies were more even, besides the top colony and a few at the bottom. The rest were very similar, while in the big cell group the sizes of the crop were more spread out. The top crops were similar in the two groups.
Both groups were affected by chalkbrood. Chalkbrood is difficult to measure, but my anecdotal eyes told me the big cell group was evidently more affected. This may have contributed to the smaller crop in this group. Would the mite population had been bigger without the chalkbrood?
In September 2004 the queens were shifted in all remaining colonies, which was 16 in the small cell group and 16 in the big cell group. During the requeening, supersedure queens were found in 7 colonies in the small cell group and in 8 colonies in the big cell group.
New breed for the rest of the test
The new queens introduced were of another breed, Carniolan. None of the colonies was treated with any substance for the mite. The test continues. The Carniolan breed in Norway is a stock selected in a breeding project by the Norwegian Beekeepers Association and has been going on for several years. The stock has a good reputation and I want to test it against the breed I mainly work with, the Elgon. Therefore I have set up an apiary with Elgons not to far away from the now Carniolan test apiary.
Cell size test with the Norwegian Beekeepers Association
Professor Stig Omholt in Norway invited scientists and beekeepers associations in the Nordic countries in 2001 to discuss the possibilities of testing small cell size. The Norwegian Beekeepers Association launched a cell size test in 2002. I am one of the test beekeepers. The results up till now look promising. Therefore more test beekeepers will be engaged during 2005 and 2006.
At last I want to thank Prof. Stig Omholt in Oslo Norway, Dee and Ed Lusby in Tucson Arizona, Dr. Eric Erickson in Tucson Arizona, the staff at Dadant in Hamilton Ohio, Raymond Cooper in Iola Kansas, Myron Kropf in Middletown Missouri and Editor Erik Osterlund in Hallsberg Sweden for illuminating discussions, without which I’m sure I wouldn’t have survived this long as a commercial beekeeper.
2006 short update
My experiences this year has confirmed what is written in this article. Winter losses was again low. And I see less of mites in my operation. I have managed shift to Elgon stock in almost all my colonies. The bees have done well even though the season has not been very good.
some years later:
1. Osterlund Erik, (2001), The Elgon Bee and Varroa Mites, American Bee Journal, March, vol 141, March, p 174-177. http://beesource.com/pov/osterlund/index.htm
2. Cowan, T.W., The Honey-bee; its Natural History, anatomy and Physiology, Houlston & Sons, London, 1890, p 180: ’The average size of a worker cell between the parallel side is 1/5th of an inch, or 0.2…. We say average, because considerable variation exists in different parts of the same comb, as both Réaumur and Huber found.’ The average 0.2 inch was 5.08 mm in naturally built combs.
3. Dennis Murrell website: http://www.bwrangler.com/ttbh.htm
Page on comb structure: http://www.bwrangler.com/ncom.htm
Finally, there is no observation that small cell size have any negative effect on the performance of the bee colony.