Varroa resistant bees in Norway

It is positive that the research community is becoming increasingly focused on varro-resistant honeybees. The latest report comes from a doctoral student, Melissa Oddie. She has started an investigation why a Norwegian beekeeper’s population of bee colonies can be called resistant because, according to his information, he hasn’t treated his bees against varroa in at least 19 years. Their article is a pre-presentation before it is peer reviewed. It could be read and downloaded here when I was writing this: https://peerj.com/preprints/2976.pdf

The result showed that the varroa population of the test bees had a growth rate of 0.87, ie a decrease over time. While the non-resistant control colonies had a growth rate of 1.24, i.e. an increase of the mite population over time.

 

Positive details in the study

  1. One of the beekeeper’s own apiaries was used and its colonies were used in the test.. Thus, no queen was introduced to other types of bees in another place. The resistant bees and their queens were tested in their normal environment.
  2. The distance between the test and the control colonies were big, 60 km.

 

Details missing

  1. The name of the beekeeper. He had earned a place among the authors.
  2. The beekeeper has exchanged breeding material with another commercial beekeeper since 2004. This beekeeper has also not been treating his bees for many years.
  3. The number of bee colonies forming the resistant colony population is not mentioned.
  4. The cell size used by the beekeeper is 4.9 mm, ie small cellsize, for almost as many years as he did not treat against varroa.
  5. The cell size of the control colonies is also not mentioned. Is it also 4.9 mm or larger?
  6. It is not mentioned if there are other bees close to the test and control colonies. The test beekeeper has several apiaries. If any of them are near the test apiary, it would probably not affect the test. How many other type of bees could be found near the test and control apiaries (if any) is not mentioned and, if so, the distance to these bees. It is important for the reinvasion risk.
  7. Nothing is mentioned of annual losses for the years backwards for the test and control colonies. It may be of secondary significance and these figures may also not have been secured. However, some kind of data about of the losses at the beginning of the adaptation of the test bees could have been interesting to take part of. But the article is inspiring anyhow.
  8. There are also no tips for beekeepers inspired by their article to start developing their bees to become resistant. Of course, it is not a task of the test I understand, but some kind of comment about this has been positive since many beekeepers will certainly appreciate the article and be inspired by it. However, such advice I look forward to find in follow-up articles in bee magazines.

Which bees are the best?

Bees can develop rapidly in spring, or slowly, or in between. Carnica bees (Carniolans) are usually known to develop rapidly in spring, while black bees (A. m. mellifera, AMM) usually develops slowly. If the bees are developing quickly, they eat more food as they make more brood. It is brood that requires a lot of food, both for feeding the young and for keeping brood temperature in the hive.
Carnica bees usually start brooding early and strong. Mostly they react quickly to availability of fresh pollen, especially later in summer when chilly weather keep them inside the hive and brooding thus is greatly reduced. The AMM bees are often adapted to a late honey flow and weak early flows. The late heather flow in the Nordic countries has been involved in forming this bee. The yellow Italian bees come from a warmer climate where it may be smaller weaker honey flows during a long time of the season. They often tend to breed most of the time the whole year long. Therefore, there have been management methods of beekeepers in Sweden to handle this. For example, to hinder the bees brooding in winter by wintering them in one box only with ten frames of Swedish standard frames (366 x 222 mm). Then they let the bees fill the box with as much sugar solution that they can, thus leaving very little space left for brood. Such a small box full of Italian bees should not be well insulated. But if the colony is not very strong, a good insulation is necessary in our climate.
A cold spring like this in 2017 is a hard test for the bees and the beekeeper. It may not have been such a cold spring since temperatures began to be measured in Sweden, probably since the mid 18 hundreds.

Which bees are then the best?

For survival of the bees, they obviously should develop slowly in spring, and have no or very very little brood in winter. Thus they are more able to economize with the food so that it lasts until they can collect more fresh nectar from flowers in nature. They must also be resistant to diseases that can create difficulties when spring is cold and long, especially nosema.
But a beekeeper who wants a little better honeycrop than just 10-15 kg in average, and is trying to make a living from his bees must have a little different goal for his bees. This beekeeper needs a bee that can be wintered stronger than just on one box of smaller frames. It shouldn’t breed in winter. But it should develop strong in spring, if there is food enough.

I prefer the Langstroth length of the frame, to get strong colonies. The frame height can be anyone of the available options. The goal is as strong a colony as possible going into winter, with plenty of food. Preferably at least a box on top full of feed.
Large amounts of food are not needed for wintering, but for making brood coming spring. Where I live, with my bees, brooding begins in smaller amounts in late winter and increases at the beginning of March. Later in March the queen lays a lot, especially after the main cleansing flight that normally takes place later in March.
A year like this, the amount of brood will vary in line with the ability for the bees to fly out of the hive and get water for the brood. Bee types differ in ability of flying at lower temperatures. The beekeeper must ensure that there are always at least 2 frames with capped food so that the bees can make brood without risking running out of food. (Italian bees, unfortunately, often breed strongly with almost no food left, which is very risky for the bees, with starvation as the result.)

 A few days ago temperature was 8-10 °C. Many colonies was more or less packed in the first super above the queen excluder. They got two more supers if they were more packed, one more supers if they were less packed. Today 18 May it is summer. The picture shows colonies in an apiary before they were supered a few days ago.

In order to be able to get a crop from early honey flows, the bees must be strong enough to fill at least one super above the queen excluder (one box more than expected room for the broodnest of the queen) and a second for the development of the strength of the bees, when the first early flow begins, which usually is from winter rape.
A long cold spring like this means you have to check the bees frequently to ensure they have food enough. The best is to give the bees capped food combs. I get them from my stock of capped food combs which I established in November removing some outer food combs from heavy hives in which the bee strength was smaller. Those combs were replaced with insulation dummy combs. Food combs can also come from colonies that have died during winter. Combs that have been heavily defecated on and can not be cleaned are not used. A few spots of defecation a strong colony can handle. Another option when food combs are not available is sugar fondant. The last option is sugar solution. It will can cause the colonies to make too much brood.
Especially a spring like this you see a difference in the bee colonies. There are those who have bred too much and used up too much food. And there are those that responded too much to the cold periods and stopped brooding almost altogether. And then there are the perfect ones that did not need extra food but still developed continously and developed enough good strength, albeit not the very strongest. Then there are those which developed very well but needed some extra food combs. The two last types of bees are those that should be favored when selecting for breeders. First priority is though of course Varroa resistance.

Varroa project 2014 –>

This test is accomplished and funded by LP:s biodling bee equipement supplier, Arne Andersson sideline beekeeper and Erik Österlund sideline beekeeper.

 

GOAL FOR THE PROJECT

The goal for this test is to see if it is possible:

  • to improve mite resistance in apiaries with 5-10 colonies,
  • to understand the impact of ”isolation” of 3-5 km (3-4 miles) to other beekeepers
  • to understand the role of small cell size in the broodnest
  • to see the role of differentiated treatment of varroa mites, that is treatment of only those colonies that exceed a defined varroa level

 

PLANNED MANAGEMENT

Avoid silent robbery

The colonies should be managed as similar as possible to a beekeeper that want to increase the number of colonies with an extensive management method. It should interfere as little as possible with the bees activities and avoid disturbing parameters, which could happen when you open the colonies often, like for example starting robbing in nectar droughts. It could be enough with silent robbery, a robbery activity that you don’t notice. That could be enough to destroy a test, in that the varroa populations are evened out

3% strategy

Therefore we decided to maximize the number of hives for the two main groups in this test to 10 hives (5+5). We also decided to make two or three alcohol washes with 1 dl of bees to monitor the varroa level during the season. When the Varroa level was higher than 3% we planned to treat with thymol. If it appeared wingless bees in or in front of a hive treatment was also to be performed.

Use of thymol

We decided to use dish cloth pads drenched with fluid thymol mixed with a minimal amount of rubbing alcohol (to lower the melting point of the thymol crystals) as treatment against mites when decision was made to treat. You can see how they are done and used in this article: http://elgon.es/resistancebreeding.html

Crop and feeding

If possible a harvest should be taken and sugar solution (or honey) fed at the end of season after harvest to ensure enough food for winter. The goal should be to leave a fair amount of honey for winter, if possible as much as you think your bees have got genetics to make it through the length of your winters.

Nucs and splits

Increase are made by making so called walk away splits that remain in the same apiary as the mother colony. These are allowed make there own queens, or supplied with mature queen cells made from a good colony in the apiary. This should also be the swarm prevention method.

Elgon and Carnica/Carniolan

We choose to use two different types of bees in the project. One type that has been selected for varroa resistance during many years, Elgon, that has been bred with this purpose since 1989. Another type that hasn’t been selected less, but in other traits are good, pure bred Carnica/Carniolan bees.

 

FITNESS

Increase of the number of colonies

The number of colonies wintered each autumn would be a way to measure the difference in success between the two parts (large and small cell size) of each main group, Elgons and Carniolans. To be counted in the increase would be the colonies that are brought out from the apiaries and the project, a kind of crop. What we measure will thus be the production of new colonies and survival of colonies to the next season, the difference of fitness. If colonies survive to the next season is not only dependent on the varroa and virus levels in the colonies, but also on other circumstances that influence the survival and how a colony thrive, for example other pathogens like nosema and quality of food like pollen throughout the season.

Start and number of years

Instead of starting the project with 5+5 colonies with each type of bees, we have choosen to start from a fewer number of hives and increase the numbers. And we plan to continue the project for at least 3-4 years. We have choosen areas for the test that are low in nectar and pollen sources. That’s also a reason why the number of hives are restricted to five in each part, which makes a total maximum for each type of bees 5+5 colonies, 5 small cell and 5 large cell.

 

CARNICA

Four Carniolan colonies, all of them being sister queens from a pure bred Carnica/Carniolan stock, were divided in two groups with 30 m between the groups. These groups were placed in a deeply forested area far enough from the Elgon bees. Here it was no farm in the neighborhood, like it is where the Elgon bees are placed. One group was established on Mann Lake’s standard plastic frame, 4.95 mm cell size. The other on Anel plastic frames with 5.5 mm cell size. Frame size medium (448 x 159 m). Hive type well insulated styren plastic boxes.

The Carnica bees 2014-2015

The Carniolan queens we received in 2013 were introduced into Elgon small cell (SC) colonies on 4.9 mm cell size shallow sized frames (448 x 137 mm). The Elgons are adapted to SC during many years and if nurse bees fed and born in SC should be of importance that criterium should then be met for this test. The Carniolans in their homeland could not draw and thus live well on ”SC”. Here they were adapted immediately through this process, but they could not draw wax foundation 4.9 well even though they lived well on 4.9. Probably because they were not genetically adapted to small cells. Mann Lakes 4.9 they could draw well. Probably because of the high plastic cell wall starters which they couldn’t remodel

In 2014 half of the Carniolans got only Mann Lake’s 4.9 (SC), half got Anels 5.5 (large cell, LC). During 2014 they were this way transferred to these two types of frames. Increasing cell size in the LC-group up to 5.5 was no problem either as they were adapted to 5.5 in their genetics before they came here.

All the Carnica/Carniolan colonies were treated with thymol in 2013, but not much, and in September 2014 after they were moved to their test destination. No DWV-bees were observed in 2014.

The LC part of the Carnica bees 2015

In 2015 in June the LC-group (both colonies) showed 6% varroa level and crippled winged bees, one colony quite badly. They both got one treatment with two homemade thymol pads with about 5 gr thymol each. The LC-bees gave no crop. The Varroa level had not increased again very much and was only about 1 %.

The SC part of the Carnica bees 2015

The SC colonies had 0.3% and 1% varroa level respectively. In beginning of June a so called walk away split was made from one of the SC-colonies. The new queen then of course mated to very closely related drones.

The strongest SC-colony gave a small crop.

In September the SC-colonies still had only around 1% Varroa level. None of the colonies got any treatment in the autumn due to the low varroa levels. The SC-colonies thus got no treatment at all in 2015.

The Carnica bees 2016

The LC part of the Carnica bees 2016

The weakest of thee LC colonies didn’t make it through winter. The second one looked fine in May.

The weather was then rainy and chilly for several weeks, and when the beekeeper returned in late May to monitor varroa levels, in the remaining LC-colony he only found some dead brood and a few dead bees on the bottom.

The SC part of the Carnica bees 2016

In spring 2016 the now three SC-colonies were doing fine, two of them though small in size.

In the three SC-colonies the varroa levels were 3-4% in late May and some crippled winged bees appeared. Thymol pads were applied in June. A walk away split was made from the strongest SC-colony. The weather was unfavorable and the other three robbed the split. It thus died.

In September the three SC-colonies looked fine and got no treatment. The bees superceded the three year old queen.

The Carnica bees 2016-2017

The three SC-colonies were moved to an apiary with better resources for nectar and pollen. Some more pure bred Carnica queens were received in 2016. They will be used to biuld up the test apiaries again. Daughters will be bred from these and mated in the apiary with drones from the survivor colonies of the SC bees.

The whole season of 2016 was bad in producing nectar and pollen. The colonies had a hard time growing in size. It was late in the season when complementary feeding in preparation for winter was done that they grew somewhat in strength. That was the reason these bees were moved to a better place for food.

All three colonies actually were weaker than wanted going into winter. Two colonies made it through winter. The third and weakest died. This colony had probably survived if it had been fed honey (or fondant) and pollen during the worst nectar- and pollen drought periods.

 

ELGON

Six Elgon colonies of two different mother lines divided in two groups with 3 colonies each were set up. These groups were placed in a deeply forested area with a small farm in the neighbourhood. The two groups were placed about 700 meters from each other. One group got Mann Lake’s standard plastic frame with small cells (SC), 4.95 mm cell size. The other got Anel plastic frames with Large cells (LC), 5.5 mm.

Two sister groups were used. One sister group consisted of 4 queens, 2 SC and 2 LC. The other sister group had two queens, 1 SC and 1 LC. Frame size is medium, (448 x 159 mm). Hive type with well insulated styren plastic boxes.

The Elgon bees 2014-2015

The Elgon groups were established with new queens in 2014 and transfered successfully to Mann Lake’s 4.9 and with big difficulties to Anels 5.5.

The queens in the LC colonies were very hesitant to lay in their large cells. One queen totally refused.The broodnest of that queen consisted of only two shallow SC-frames. The resulting colony was of course small going into winter in 2014, but it wintered together with the other two LC colonies in their test apiary.

Most of the colonies, SC and LC, were treated in 2014 with thymol but mostly only in May. So this Elgon test groups of 3+3 were not managed in regard to the Varroa mites, similar to the Carnica groups. In the Carnica colonies the varroa populations were evened out between them, by treating them with home made thymol pads in September 2014.

The Elgon test colonies were taken from different apiaries and the varroa level in the colonies were not known when they were brought to the test site in late August. Earlier in 2014 the colonies who had wingless bees were treated with thymol, in May that was.

The LC part of the Elgon bees 2014-2015

In spring 2015 the Elgon LC group continued to create problems as the bees protested against using LC combs for brood by supersedure their queens, probably in an adaption process.

In April before grafting time and any drones were flying one LC-colony was queenless. The new virgin queen had of course failed to mate and was gone. I combined the queenless colony with the mini colony (the one with the queen that had refused to lay but in the two shallows). This queen still refused to lay in any other comb than the two shallows, so I tried to fool them by giving them a couple of 5.3 mm cell sized plastic frames on each side of the SC combs. That worked. When the 5.3 were filled on each side of the 4.9 they started on the 5.5 next to the 5.3.

It seems it is the workers that prepare the cells for laying, not the queens that are deciding in which cells to lay. (This experience is also in line with what is written in old books from beginning of 1900, that when broodnest have 5.1 you could use 5.6 in honey supers without excluder as the queen didn’t lay in the 5.6.)

In late April 2015 the third (now the second as the other two were combined) LC-colony had a virgin. They were also trying to supersedure their queen. No drones available yet. So she failed. The colony got a queen cell in second half of May. That queen got laying. This colony had 5% varroa level in August and got thymol.

The first colony (former first and second combined) got a small piece of thymol (actually both parts that were combined got half a piece each) early in spring to help against eventual patoghen problems as they had different kind of problems (weak but queenright and queenless). This colony showed only 0.3% Varroa level in August and got no treatment.

The SC part of the Elgon bees 2014-2015

In 2015 the three Elgon SC colonies developed well. Splits were made from two of them. One failed, but finally got a laying queen very late in season. It ended up weak. It was lost during coming winter, the only loss of the Elgons. The smallest of the overwintered colonies had a queen that was laying badly. It was killed and replaced by a ripe queencell.

Four of the now five colonies showed crippled winged bees in July and had Varroa levels between 2-7%. Even the 2% colony showed a few DWV-bees telling me the virus levels in the colonies were quite high. One 3% had no DWV, the weak one mentioned above and it was the only one that didn’t get treatment.

Because the varroa populations in the colonies weren’t allowed to grow strongly (still there were enough viruses in 2015 after years of somewhat higher varroa and virus pressure in the Elgon apiaries of Erik Österlund), the virus amounts in the colonies decreased and also there was no silent robbery. And the varroa populations were evened out at a low level. Thus the situation now was much more comparable with the varroalevels in the Carnica colonies in autumn 2014

The Elgon bees had better nectar flows than the Carnica in 2015 and the Elgon colonies gave a good crop from the Heather in 2015. The average crop was about the same for both SC and LC colonies. In August none of the SC Elgons had above 3% varroa level. They had 0%-3%, and got no more thymol. No colony swarmed in any of the test apiaries.

The Elgon bees 2016

In spring 2016 one of the Elgons, the very weak one in the SC-group died (as mentioned above). Both LC colonies survived.

The LC part of the Elgon bees 2016

In the LC-group splits were made from both colonies. Weather was bad and one failed to produce a laying queen. It got a new ripe queen cell. The parts with the ”old” queens (from the year before) both superseded their queens, in line with experiences in 2015. This year they waited until beginning of summer when there were drones around. Maybe the bees had adapted somewhat to LC now.

The season of 2016 was very bad so no crop was secured from the LC-group. In spring the varroa levels were 0.3% in all four colonies (they became four after splitting in late May). In early September it was 0% – 8.6% – 0.9% – 4%. The two with highest levels were treated with thymol. The other two not. We can see that two colonies had very low levels of Varroa mites. This indicates a good genetic set up for Varroa resistance, also to be able to work with large cells apparently. The queens in the colonies with low Varroa level are sisters, mated in the test apiary. They are daughters to one of the colonies in the apiary, one in a split. The other as a result of supersedure in the mother colony producing this split.

The SC part of the Elgon bees 2016

The four remaining colonies in the SC-group gave a split each. Season was bad and two of the splits failed. A small crop was secured from the strongest of the colonies.

The two colonies with two year old queens supersedured these later in season. The 6 colonies all had 0.3% varroa levels in spring. In August the varroa levels were between 0-1.7%. As we had decided not to keep more than five colonies in each of the four parts of the test, colony no 6 of the SC-ones (the one with 1.7%) was removed from the test area. It wastreated with a small amount of formic acid to get an idea of the mite load and also test the shaker method. It fell 10 mites in a couple of days. The other 5 colonies remaining at the test site didn’t get any treatment.

The Elgon bees in the beginning of 2017

All four colonies in the LC group wintered well, in spite of that two of them were almost too weak, those that had had the highest Varroa levels and been treated.

One of the five SC colonies defecated a lot on the outside of the hive, though not much inside. They did not have a large amount of honey left for winter the previous autumn. And it was of good wintering quality. The winter before all colonies had had a large amount of difficult winter honey, from heather. The colony that died was the strongest and smallest Varroa level. It measured 0% on 400 bees. The was a good amount of food left in the hive after it had died. The colony had an old queen, and just a few meters there had been quite some traffic during late winter from a tree harvester. The other colonies looked fine, with almost no defecation.

Harvest and Varroa level 2015 and 2016 in SC and LC parts of the Carnica bees. The sites for Carnica and Elgon bees are not comparable as the Carnica site was didn’t have the same amount of food sources. Click on the picture to get it bigger and of better quality.

 

Harvest and Varroa level 2015 and 2016 in the SC and LC parts of the Elgon bees.

RESULTS

Losses

The losses in the Elgon groups have been quite normal, on the lower side. It has in percentage been higher in the Carnica groups, especially among the LC bees. The higher amount of losses can be explained by the low availability of pollen and nectar, especially during 2016. That’s why the test site for the Carnica bees has been moved. One conclusion is that during times with small amounts of available pollen and nectar a solution could be to feed the colonies fondant/honey and pollen to develop healthier and stronger colonies better adapted to survive winter.

The strategy of 3 %

The strategy to measure the Varroa level a couple of times during the season and use Varroa treatment (dish cloth pads, about 50 x 58 x 1.5 mm [2”x2”x1/16”], drenched in thymol) when/if the Varroa level is higher than 3 % (only treatmnent in these colonies, not in those below 3 %) has minimized reinfestation, maybe altogether. You thus get a true picture of the Varroa level in the colonies and thus a better selection of the most resistant colonies and the most susceptible ones. You could for example have expected that the different cell size groups had affected each other so that eventual difference in the varroa levels had evened out, especially among the Carnica bees as the two groups there were only 30 m apart.

Little need for Varroa treatment

Relatively little of Varroa treatment has been used, probably partly explained by the absence of reinfestation, no silent robbing. Most treatment has been used in the LC colonies of both the Elgon (2016 when reinfestation had been removed) and Carnica (2015, in 2016 there was no LC left) colonies.

The strategy of 3 % seems to have eliminated the need of Varroa treatment in the SC part of the Elgon bees due to elimination of reinfestation and enough good development of the varroa resistance with the Elgon bees.

This strategy has also lessened the need for varroa treatment to every second year with the SC part of the Carnica colonies and the need for treatment then has been small. Thymol in this context has been effective.

Cell size and fitness

In the LC part of the Carnica bees the need for treatment has been bigger probably because of a quicker development of the Varroa population. It seems fitness has been lower here probably partly due to the bad pollen and nectar availability. But fitness may also be lower because of other reasons. The Carnica LC colony that died in May did not die due to high varroa level. Lack of protein and/or other pathogens (like nosema) can be the cause. The Carnica test site is moved to a place with better food sources.

One can object to this conclusion of lower fitness for LC bees because the number of colonies are low.

On the other hand were all original queens in the Carnica group sisters and all colonies in SC and LC groups (Elgon and Carnica) are behaving consistent in this respect. And any difference in fitness between the two cell size groups among the Carnica bees should have been to the advantage of the LC colonies because the SC colonies had become inbred. Usually follows a lower immune system with inbreeding. Possible impact of this small distance would have been small(-er) difference in the varroa levels between the two groups due to evening out of the varroa populations. The 3% strategy, measuring varroa levels and treatment when it was above 3%, lowered the varroa populations enough to eliminate (totally or enough) the silent robbery.

In 2016 the only colonies that needed treatment were in the LC colonies of the Elgon bees. It should though be noted that with a stock of bees that have been selected for Varroa resistance it is possible to find colonies that are resistant also on large cells. Two colonies (with sisters queens) had very low levels of Varroa mites.

The honey crops, the bee strength of the colonies indicates, and the resulting number of colonies in the SC and LC parts of the stocks of bees indicates that it is no disadvantage to use small cells in the broodnest, rather the contrary.

 Summary of production of new bee colonies, increase in the number of wintered bee colonies. These figures could be seen as a measure of the vitality of the different cell size groups. There is a difference to the benefit of SC bees both in the E group (Elgon bees) and the C group (Carnica bees). Click on the pictures to get them bigger and of better quality.

 

Suggestion on a breeding program for increasing Varroa resistance in a bee population. The background for these suggestion is the results of this project, so far.

 

Reinvasion is worst

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.

Learning and teaching

 

Hans-Otto Johnsen was very skilled already in his youth keeping old American cars and trucks going. That skill can be very handy for a commercial beekeeper.

For many years he worked as an expert on explosives, but he got poisoned by nitroglycerine and had to change his job for making a living, so he turned to beekeeping.

At the university

For a number of years he worked as a technician under Prof. Stig Omholt in Norway and at the same time developing his commercial operation. His experience from these years has helped him in developing his Varroa resistant bee stock.

HAns-Otto brood A good brood comb in one of his Norwegian type of combs before he switched to medium Langstroth size.

Quite soon he got to know me and wanted Elgon stock to work with. He imported quite a number of splits from me. He kept track of the Varroa levels in the colonies and stopped using any type of chemical to fight anything in the hives. He wanted his bees to develop their ability to survive, which they did.

Hans-Otto & Ed Ed Lusby and Hans-Otto discussing small cell beekeeping at a fuel filling stop on our way to one of the apiaries of Lusbys’ in the Sonoran desert.

In America

We travelled together several times to America and studied small cell beekeepers and wax foundation producers. Hans-Otto bought equipment and started producing wax foundation, small cell and large cell as well as different sizes of drone foundation. His mechanical and engineer abilities showed themselves to be very useful as he changed and improved the equipment, for example the cooling of the drum for producing rolls of uniform sheet for feeding the plain and foundation rollers. Also the setup of plain and foundation rollers needed according to his opinion more controls of individual speeds for different parts of the production process, which he included in the setup.

Hans-Otto and GAry Dadnt Hans-Otto and Gary Dadant discussing wax foundation production during a visit with Dadant’s in Hamilton.

Research

He started to plan and set up different tests for looking at the effects of different cell sizes in brood combs and to produce virus free drones to mate with virgin queens. He saw that bees easier recognized (and removed) when drone brood was infested with mites when these cells were smaller, which they naturally are with smaller worker brood cells. He also saw that mites more readily infested the biggest drone cells.

He was involved in small cell tests, of his own and together with others. One can be found here: http://beesource.com/point-of-view/hans-otto-johnsen/survival-of-a-commercial-beekeeper-in-norway/

Today Hans-Otto has research money from the Department of Agriculture in Norway.

Resistant stock

He developed his bees in quite isolated areas, but not totally isolated, so sometimes the bees were mated to carniolans, buckfasts and the native brown bee (Mellifera mellifera). He also worked together with Terje Reinertsen, another Norwegian beekeeper, very similar to him when it comes to beekeeping. They exchanged breeding material. Both of them have discovered that their bees teach other bees how to get rid of mites. It seems this ability to teach new bees is very important knowledge when developing a Varroa resistant stock.

Today Hans-Otto hasn’t treated his bees for 15 years. The levels of mites are normally very low in his and Terje’s colonies and he never sees any wingless bees. In 2014 the bees of Terje were tested for Varroa levels by the Norwegian Beekeeping Association in preparation for planned research. (Birøkteren, vol 131, 2015(1), pages 13 and 24. The Bee Journal of the Norwegian Beekeepers Association.) The levels were so low it was difficult to calculate the reproduction rate.

When Hans-Otto moves his bees to the heather in late summer, for producing heather honey, his bees quickly pick up quite some mites. The natural downfall of mites will then be higher until about a month before the frost will make the bees form winter cluster. Then the downfall is almost zero again.

Book contribution

In 2010 Georgia Pellegrini (https://en.wikipedia.org/wiki/Georgia_Pellegrini) published her first book on natural food: Food Heroes (http://www.amazon.com/Food-Heroes-Culinary-Preserving-Tradition/dp/1584798548) She included a chapter about Hans-Otto and his focus on natural production of honey. For example he concludes that small cell bees are more biologically optimized than large cell bees. Thus research done with small cell bees are more reliable concerning what bees are and how they react naturally. In short, research results with small bees are more reliable.

In this context it’s interesting to notify that Norwegian wax is almost pesticide free.

HansOttoJohnsen An important part in his quality control is producing wax foundation as he thinks will be the best help for the bees.

Learning and teaching

Today we understand that adaptation of bees to fighting Varroa isn’t only selection breeding, natural or beekeepers’, for changing the DNA composition, but also epigenteic adaptation, the change of expression of the DNA as a result of changed environmental pressure on the bees. This turns the focus to the importance of locally adapted bee stock. Now research is going on with a third adaptation step, how bees learn how to deal with challenges and how they pass on this knowledge to other bees, worker bees to worker bees.

Hans-Otto caught a carniolan swarm of not resistant large bees that choose one of his swarm traps for their new home. After establishing this swarm in one of his apiaries he shifted its place with one of his resistant colonies. So this nonresistant colony received the field bees of a resistant colony. Afterwards they both behaved like resistant colonies.

One year he bough buckfast virgin queens not selected for Varroa resistance. He put them in splits made from his bees. The virgins mated in his apiaries. These splits were spread out in different apiaries of his. For two years they kept their colonies working fine and resistant to mites as good as his other colonies.

Now these two experiments absolutely are food for thought.

More than15 minutes of fame

Definitely Hans-Otto Johnsen is worthy of more than the 15 minutes of fame, one commentator thought was enough.

Treatment select for increased reproduction rate

Varroa mites multiply in bee larvae. After they come out of the cell when the bee is fully formed, they sit on the adult bees and suck hemolymph.

It was observed many years ago that during the brood period of the bees, 2/3 of the mites was found in the capped bee brood cells while 1/3 was on the bees.

VarroaBin2 Varroa mites on bees. Many years ago 1/3 of the mites were sitting on bees while 2/3 was found in the capped brood. Today this has changed to 15% and 85%. (Photo: Anders Berg)

If the mites had been sitting longer time on the bees than they did, before they returned into a brood cell, a greater proportion than 1/3 had been found on the bees. If they had been sitting less time there would have been a smaller proportion found on adult bees. The shorter the time the varroa mites are sitting on adult bees, the faster they return into a new brood cell to reproduce. This would increase the speed of varroa reproduction in the bee colony.

It is thus from the beekeeper’s and the bee colony’s point of view desirable that the mites are sitting as long as possible on the bees, resulting in a slower development of the varroa population. So, if the proportion of mites had been ½ on the bees and ½ in capped brood, this would have been better than that found for a number of years ago when varroa mites had arrived.

In early December 2015, two professional beekeepers from the Spanish mainland came to the small island of La Palma, one of the Canary Islands, and lectured on the varroa problem (http://archiv.resistantbees.com/phoretische-varroen). One of them was Manuel Izquierdo Garcia, a biologist at the University of Seville. (Thanks Rüdiger Dietrich who drew my attention to this.)

30 years ago when varroa mites came to Spain, the proportion of mites on the bees was 1/3 and 2/3 in capped brood. During the past 30 years, the mites’ behavior have changed. You could say that during the 30 years of conventional treatment of bees to kill mites, the mites have responded by spending less time on the bees to accelerate their reproduction rate. They have also changed the place on the bees they usually sit, from the abdomen to the middle part of the bee.

The result of this change has resulted in 15% are found on the bees (previously 33%) and 85% in the capped brood (previously 66%).

VarroaYngel2 Mites are sitting shorter time on the adult bees. Thus you find at a given time 15% of the mites on the bees today and 85 % in the brood. This have increased the reproduction rate of the varroa population.

Increased treatment

This change has consequences for beekeeping. It explains why we in Europe have had to increase treatment to kill mites. There are examples of recommendations in several countries where the fight starts in spring and continues throughout the season. And anyway, or should one say, maybe sometimes also because of this, the bees have difficulties to survive.

Powdered sugar

Some types of treatment will also be less effective due to this change. Treating with powdered sugar, only kills the mites sitting on the bees. One must fight very often if powdered sugar should have any effect of relevance.

Oxalic acid

If there are still small areas of capped brood when one uses oxalic acid against the mites, the oxalic woun’t have the effect one wants. This becomes more relevant when climate change means warmer winters, as it will be more common with brood in winter times, the time when oxalic usually are used. It becomes even more important keeping bees that really have brood-free periods during winter, also for treatment free beekeepers.

Treatment is a dead end

It is becoming increasingly clear that it is a dead end using all kinds of chemicals against varroa mites. And it is with the increased reproduction rate of the mites more difficult to select resistant bees and get areas with treatment free bees – which is the solution.

Focus on varroa resistance

All this show how important it is to focus on producing as varroa resistant bees as possible and develop management methods without chemicals. It is important that all beekeepers understand the problem and are involved at least somewhat.

Every beekeeper can at least try to identify which of his or her bee colonies are the least good in resisting varroa mites and replace the queen(s) in those. The simplest way is to just remove the queen in such a colony and let the bees rear a new of their own. It is not the best method, but a start. Then you can make more steps in improving your bees, depending on interest and opportunities.

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?

 

 

More viruses due to cold weather

The weather has given the coldest May since 1962, 12 years before I started with bees. The bees have had a hard time getting enough pollen to keep up egglaying to reach optimum nectar gathering strength when summer comes.

In agricultural areas winter rape has given some nectar during the few hours with good weather. It’s still in bloom… In the forest small blueberry bushes which in many areas cover the ground has done the same. Now lingonberry flowers give nectar and pollen.

Pollen is essential as amino acid and protein source. These are used for almost every thing the bees need to function as they should, for example the immune system.

This year I’ve seen wingless bees in colonies with no big population of mites, eve if it’s somewhat bigger than it had been if the colonies had been treated with an effective miticide last year. I use thymol only when wingless bees appear, on the hardboard in front of the entrance or on the brood combs.

Nosema have probably also contributed to health problems with the bees this cold May, in combination with viruses and plant protection chemicals, it can be disastrous.

Now sun and mating temperature for honey bee queens came upon us the other day. Nature dried up. The hard boards appeared “empty”. Bees are working like maniacs. Nectar is filling the supers, even in the forest. It must be the lingonberries.

More Virus lingonblom To the left there is a Swedish blueberry plant showing some berry babies. Now lingonberries are blooming.

But happiness is not perfect. In most colonies there hasn’t been egglaying as it should this time of the year. The field bees that will fly to death will not all be replaced by hatching new bees. But if the fine weather will continue the bees may collect quite some early honey, in spite of the earlier bad weather. And here in Sweden we hope for a good amount of wild raspberry flowers.

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.

 

The Beeshakers

‘The Beeshakers’ would be a good name for a pop/rock/soul-band/group, wouldn’t it? Why not a group of beekeepers that have control of their bees and the Varroa infestation?

Regardless of if you are on the path of becoming treatment free or treating with whatever to get rid of pathogens and parasites in your hives (and creating other problems probably along the way – that goes for both groups unfortunately). Agree we can that the world would be a better place for bees and men without killers. That’s why treatment free is the goal!

A year ago I wrote about the bee shaker: http://www.elgon.es/diary/?p=354 Here are some more tips how to get control of the Varroa situation in the hive.

When a colony has problems you can speculate and discuss about how many mites there are in the colony. If that’s why the colony is dwindling. With a high number of mites often follows virus problems, more sensitivity to plant protection chemicals and more susceptibility to Nosemas, and all of this together in a spinning wheel. You can know the mite infestation much better with this simple method that is quick and done on the spot in the apiary, with some training in a few minutes per hive.

 

Make the beeshaker

I used two plastic bottles containing peanut butter of the brand Skippy, a bee tight but not varroa tight netting, mesh size 3 mm, a plate shears, a proper sized hole saw (in this case for a 60 mm hole) and a soldering iron at 80-100 watts.

Biskak1

Get rid of the peanut butter and wash the bottles. Saw holes in the lids. Cut a piece of mesh so it fits inside the lids and covering the hole. Put one of the lids on a table, then the piece of mesh, finally the other lid upside down. Keep it all together with one hand (or some one else’s hands). Solder the caps with the piece of netting in between.

Biskak2Biskak3Biskak4

Pour one deciliter (3.5 fl oz UK; 3.4 fl oz US) in one of the bottles. Mark the waterline around the bottle with a black marker pen. Get rid of the water. Now you have calibrated the bee shaker. When you fill this jar with live bees up to the black line you have close to or exactly or somewhat above 300 bees, enough accurate so you don’t need to count them. (If you use 2/3 of a deciliter you get 200 bees.)

Biskak5

 

Make a test

Don’t take bees close to the entrance. They have bad correlation to the real amount of mites in the colony, fewer mites on those bees. Take bees relatively close to the brood, but not from a comb with the queen (poor queen if she should end up in the shaker). You may well take bees from a comb without brood, but close to the brood. In the upper brood box is a good choice if you use two brood boxes. Check for the queen! Avoid the outermost comb in the box, unless brood is close and it’s filled with bees. Most secure and quickest is if you use queen excluder and you have super(s) above it (depends on the season of course). Take bees from the center of the first super close to the excluder.

Take the jar with the black line (black color doesn’t fade so easily by the sun), hold the opening close to bees on the comb and move it from below upwards. Bees will tumble down. Hit the bottom of the jar gently against something sometimes so that the bees will be shaken down on the bottom. You then see easier when you have enough of them.

Biskak6

Before this procedure you have poured 2 deciliter of some kind of high content alcohol fluid into the other jar. The soldered caps are on top of it (there’s a hole you know you can pour through). Pour the alcohol into the jar with the bees. They die. Screw the lids with the other jar onto the jar with the bees and the alcohol. Shake it for a minute, not too hard and not too soft, “lagom” as we say in Sweden (a frequently used word when you don’t know what word to use). Turn the shaker upside down. The alcohol and the mites will go down. The bees stay above. Lift the shaker up towards heaven. The light will shine through and you can count the mites. (Live mites now killed will sink to the bottom. Dry mites from natural downfall will float. Just want to make clear the difference.) Recycle the alcohol through a fine mesh into the now empty jar to get it ready for the next hive.

Biskak7 Randy Oliver counting

Biskak8

 

Count and calculate

You may find 9 mites on your 300 bees (which you DON’T have to count, it’s enough with the calibration done to get an enough good estimation of the mite infestation). That’s 9/300 = 3/100 = 3% infestation. You can find that small or big, depending on when you did the measurement and what you are up to. Maybe you are in the middle of a breeding program for Varroa resistance. Maybe you want to find out when to treat, so you will not treat to late, or making an unnecessary treatment.

In spring, especially in a breeding program for resistance, you don’t want 3% infestation. If you’re in a breeding program you will probably take another measurement a month later. If you’re not, you maybe want to treat now, if you find something that’s good using in spring (there’s really only one option here that is least damaging in different respect, thymol).

If you get 3% after the main crop in the middle of July or in the beginning of August (or September maybe), you may decide not to treat if you’re in a breeding program. If you’re not and the bees will be without brood in November or December (on higher latitudes in Europe and Canada) and you plan to use Oxalic acid (which I don’t recommend for different reasons [though you’re the boss in your operation]) you may wait until then. If you consider pesticide strips or Apiguard (Thymol) or Formic acid, you may decide for that now.

If you get 3% in October, November just prior using Oxalic, you may decide not to use any Oxalic. Like a friend in our resistance breeding program here in Sweden. He has the limit 5% for deciding when to treat. All colonies below that limit don’t get any treatment with him.

If you treat all your colonies whatever figures you get in your measurements because you hate the mites that much, you get at least figures you can use in selecting the ones with the highest numbers. Those are the ones that should have their queens shifted in some way.

 

More to read

http://scientificbeekeeping.com/sick-bees-part-11-mite-monitoring-methods/ eller kort url: http://alturl.com/np8ez

http://svenskbihalsa.se together with Google translate

Biskak9Biskak10 Another Swedish alternative of the BeeShaker, Varroa Sampling Tool, which is for sale from http://svenskbihalsa.se