Before varroan came there could be seen occasional bees with undeveloped/deformed wings in spring. Maybe it was the influence of DWV, Deformed Wing Virus. But it may also have been chilled brood. During the final phase of the pupa development to finished bee the wings are formed. Cold nights and too much of brood could maybe have caused undeveloped wings.
Today, one can probably assume that when you see a wingless bee, it’s DWV responsible. Varroa mites are paving the way for many viruses into pupae and adult bees that had not previously bothered bees. Moreover, these viruses multiply in mites. So today mites spread viruses more efficiently than when the mite had just arrived in Europe. Why that is so is another interesting discussion that probably involves the use of miticides.
The Bee Shaker
The Bee Shaker is a great way to keep track of the level of mites in the bee colony, especially in spring and late summer, so the amount of virus can be kept reasonably low by allowing people to fight the mite if it exceeds a certain degree of infestation. (If that is the strategy chosen.) A good benchmark that many use today is 3%, three mites on one hundred bees (9 mites in 300 bees/1 deciliter of bees).
It also means that to develop a bee stock towards better varroa resistance, you don’t treat against the mite, especially below a mite level of 3%, whenever in the season it is measured.
But if there are wingless bees in the bee colony? It’s usually a sign of DWV and thus too many mites. Here is the Bee Shaker again a good tool, to find out if there really is a high degree of infestation of mites when you see a wingless bee. If you decide to treat against mites if the level is high you might do it to prevent the spread of mites to other colonies nearby.
A colony with a wingless bee
Last year’s breeder queens seem to have produced many queens that have given colonies that control the mites quite well. One of these daughter queens was introduced to a colony that had problems with mites. Perhaps the biggest problem was virus.
This colony was quite weak in this spring and developed slowly, compared to the other colonies in the apiary. I concluded that I would have to check the brood nest to find out the cause. Maybe the colony was shifting their queen?
On a later visit to the apiary about June 20, I saw one, only one, wingless live bee on the hard board in front of the entrance. I then looked in the brood nest, but saw no more wingless bees on the brood frames. But the brood frames had a so called shot gun pattern with a lot of “holes” where you would have expected capped brood as the other cells on the comb contained capped brood. Many pupae seemed to have been removed by the bees. Most likely not due to inbreeding as the queen had mated in the apiary and the number Elgon colonies in the neighborhood was quite high. No trace of any brood disease could be seen so I concluded that a likely cause could be cleaning out of varroa-infested brood. Or could the bees detect virus in the pupae and remove it, without there being a mite in the cell, and remove the pupae?
Could that be the reason why the colony developed so slowly – that the bees were throwing out mites? How had they managed? The wingless bee could indicate that they had not done so well and that the amount of mites was big. Now it was time for a Bee Shaker test to find out the level of Varroa infestation. (Here you can read more about The Bee Shaker, its uses and possibilities: http://www.elgon.es/diary/?p=809)
Here you can see a video clip when doing this test (sorry I’m talking my mother tounge Swedish):
The sample showed zero (0) mites! Then it’s no use to treat, There were far too few mites in the colony. Why had there been a wingless bee recently before the test?
The brood frames looked less spotty and the colony stronger.
July 8 I was visiting the apiary again. Once again I saw a wingless bee on the hardboard. But now I knew the Varroa level was low. Still no use treating. I looked in the brood nest. The colony was a little stronger still and the brood frames had fewer “holes”. The bees look healthy. They were recovering.
Virus apparently remain in the colony for a while after mites are eradicated – by the beekeeper or the bees.
In the recent blogs you have discussed the impact of epigentic or learnt varroa defense, which is covered by worker bees of survivor stock and transferred to e.g. nucs or even to ther bees if you mix the “survivor bee” with other bees in sufficient amounts.
Now you focus on the genetic effect, in saying that changing a bad queen with a good queen may help stock to recover.
Is it fair to assume that the genetic effect is mostly VSH and the other hygienic effect, that belongs to epigentic behaviour is something else?
And furthermore, when looking at your stock statistic. What do you think is more important? Wrong question to a breeder right?
I mean the deeper point of this question. Most of the non breeder beekeepers, that cannot control drone heritage, must face a dilution of resistance genes, if they only rely on the right queens. They problem is well known, they majority of beekeepers still ignore the simple natural laws and bypass selection by heavy treatment. Otherwise, like in Africa or in Arnot forest, we all would long ago have resistance…But this is a problem of chemical industry as well, as if varroa as bee problem exist they can always hide the dramatic effects of their pesticides on bees by pointing to varroa as “the one and only reason”.
But coming back to the upper point. A “average” beekeeper has to rely on his own adapted survivor stock and should dope in reasonable time amounts his genetics with VSH gene pool….
As always the outcome is a mixture of genes and environmental impact. Learnt behavior is encouraging, as this put less importance of genetics. My experience is that splitting a healthy thriving hive is giving a quicker and better result than shifting a queen in a problem hive. But shifting a queen in a problem hive may well result after some time in a good colony. Sometimes it takes only a short time.
Every beekeeper could do something. The best a small beekeeper could do is to get a swqrm, a nuc or a split from a colony that is effective in chasing mites, being treatment free for some years. Such a colony regardless of the environment may well be able to continue to be treatment free even in a difficult environment with many bee colonies of “hostile” composition. An evidence of that is a beekeeper in Münich.
Another option is to do like Sibylle, who is active commenting on this blog too. Keeping bees enough isolated from other bees, about 3 km, and not too many, removing the worst and splitting the best. Maybe first obtained some good genetics.
Try testing bees from the brood chamber, that’s where the mites ‘live’. Testing bees elsewhere will give you a false sense of security.
Thomas Kober in southern Germany quite some years ago now tested taking samples from different places of the hive. The most significant difference was when he took bees from close to the entrance. Much fewer mites there. Possibly high up far away from the brood also a difference, but it was not so obvious. But a friend that has taken samples there got varying results, but not very big. In my blogpost: ‘The Bee Shaker – where to take the sample’ I give an example of a follow up with a sticky board.
Well,
they didn`t shift their queen while being in the middle of crisis or am I wrong?
When did you introduce the queen, Erik?
So I guess the experience is:
>Or could the bees detect virus in the pupae and remove it, without there being a mite in the cell, and remove the pupae?<
I believe they can detect virus in grown bees too and throw them out!
Why not smell them in cells or see the strange behavior of sick bees?
Now I believe:
they needed their workers first to clean out instead of nursing, later nursing started.
If you observe your hive thoroughly, crisis happens often ( virus, spores, less food, robbing, too hot, too cold, too wet, pesticides….)
you observe a sudden use of propolis, more attacks, sound of hive changes and so on.
They adapt to this!
You realize they fight something and it`s not always varroa and varroa sickness.
(Maybe the beekeepers management 🙂 )
Beekeepers always fear economic losses if bees don´t do enough foraging.
So they are not happy if their hives learn to fight themselves, doing a brood brake on their own or developing slowly.
It could be there is no harvest and the bees use their stores.
So they treat.
I think to use the bee shaker can help you to identify the cause of sickness.
And you are able to find out the level of infestation your bees can cope with.
If the level in one colony is much higher you can decide to treat or remove all capped brood not to spread disease.
For example use your best hive , good development, good stores, no defect wings, no trembling bees and now check the varroa level.
This can be your clue to what your personal bee yard can take after trying to breed mite tolerant bees and it can be a help to select.
Do you have any idea how high the mite infestation level is with apis cerana before they decline?
Sibylle
The queen was introduced last year into a problem colony, which had the same kind of problems as it showed this year. But last year I used Thymol on it without checking the mite level.
The mite level in Apis cerana colonies can be quite high, higher than in my best colonies. But the immune system is not weakened in Cerana colonies by miticides, or I guess by a lot of other chemicals or stressed by many behaviours by the beekeeper. See page 104 here: https://hal.archives-ouvertes.fr/hal-00891571/document
Actually I think Apis mellifera is better suited to deal with the mite, as Cerana can’t open and clean out drone pupae, which Mellifera can. Our problem is the high density of colonies, the use of miticides and pesticides and other stressing managements. But if only Mellifera doesn’t have to deal with miticides they can cope better with the other challenges. So if we give them an isolated enough area where they can adapt to chase mites without reinfestation from virus filled mites from heavily treated susceptible bees. Our small cell bees are quick to rob large cell bees with too high mite levels…
When they have developed their skill to chase mites they can survive much better in difficult environments. I’m convinced of that.
Just today a beekeeper asked me if he could put one colony near my AMM bee yard, his bees had been robbed and he wanted to safe them.
Nice he asked! I´ve got very strong hives now and I told him, my bees will give them some hours then his will be no more and mine will be infested with their mites!
Well, he understood. 🙂
Since I´m a hobbyist I leave my hives 40 pounds of honey or feed them with honey when they starve.
So I hope they do not rob.
But other bees want to beg into my hives often.
I`m always observing defense so I have small entrances all year through.
I believe you are right.
There are many people who say the bee colonies, treatment free, will crash after 5 years.
So I will make strong splits for 5 years to select from and see what develops before starting some honey production hives.
Even if I`m lucky to have mite tolerant stock to begin with , they are now in new locations they need to adapt to. I believe this need at least one year.
My situation being isolated can change every day and I hope they will be strong then.
When I see mites on bees ( I take pictures and scan on PC) they are mostly on bees walking on open brood near capping or near the queen or I saw them at the entrances on bees.
Now I often observe bees trying to clean their abdomen undersides on the entrance boards and I saw what looks like grooming from other bees.
Not to mistake this with a different behavior like defense or cleaning after contact with nursing bees!
Sibylle