2011 varroa levels

[The Drone Ranger]

Hi John

I wrote short article for Scottish Beekeeper making the point that all these claims for breeding resistance have been made before in the 1930's
Resistant queens were on sale then as well
At that time the most famous beekeepers of the time were convinced that foulbroud resistance could be bred in and eliminate the disease.
One of the cornerstones was the belief that the hygenic gene for brood removal was the key to success.
Les Bailey's book I mentioned is around 1969 or so about 40 years on and he explains why the project failed
It might be better to think of these traits as switches i.e. on or off not as continuously variable like a volume control
You might remember "Spinal Tap" where they thought they made their amps louder by painting a number 11 on the volume controls

[Adam]

Jimbo
Predicting the total drop is hard to predict, I hope you are right, certainly if you all treat together you will have good data but could log the whole period to get a full picture.
Some of the drops in this table of my hives might were a surpriseAttachment 815

I agree. Its an odd set of results in a way. Column 25 seemed to have a serious problem and with apistan (no effect) and thymol treatments it still produced loads of varroa after Oxalic Acid. Maybe the thymol treatments were too far apart. C21 seems pretty well varroa free. 8 had 4 thymol treatments and still threw out loads of varroa after Oxalic treatment later on. The delays between treatment and 'mites out' is also quite marked in some cases. It has to be said that Apiguard seemed to be generally effective.

I admit that I don't monitor varroa drop as thoroughly as perhaps I should and I make the assumption that a double treatment of Apiguard will do the trick followed up by Oxalic Acid in the winter. However there does seem to be the odd hive which persists wil varroa after treatment - I had one of these a couple of years ago - I was embarassed when the bee inspector came late in September. He gave me an different treatment which produced a large drop soon after.

[Jon]

One of the cornerstones was the belief that the hygenic gene for brood removal was the key to success.

That's the issue though, it is a false assumption to imagine that hygienic behaviour is going to be controlled by a single gene.
You need to get Geeky Jim or Geeky Gav to explain chapter and verse but I think the explanation on the Glenn apiaries site fits the observations well.

[The Drone Ranger]

Jimbo
Tramping round is the snow is no fun
I decided home made thymol and oxalic acid treatment was the best compromise.
Didn't really give formic a chance (cowardly me)
I think its whether bees emerge at peak treatment strength with thymol.
The timing of treatments needs some investigating
Your breeding group could get the wellies on and gather some data

[The Drone Ranger]

That's the issue though, it is a false assumption to imagine that hygienic behaviour is going to be controlled by a single gene.
You need to get Geeky Jim or Geeky Gav to explain chapter and verse but I think the explanation on the Glenn apiaries site fits the observations well.

Jon
I am with you there- but heres the dillema- If you can't breed resistance yourself are you going to abandon your breeding AMM project and buy Primorsky hybrids instead?
If the next generation are not hygenic do you just carry on buying queens ?
The notion that AMM were unable to deal with acarine led to its near replacement with Italian and Carnica.
Are we all off on another similar journey.
Not one switch I agree but many switches all which need to be on and fixed in the breeding population.
Each switch affecting more than one thing like a complicated chain of two way light switches.
If you have resistant bees and don't treat then my bees are doomed eventually.
Likewise your AMM are doomed if I have resistant primosky hybrids bees and dont treat.

[gavin]

I'd use the word recessionary in a different context. For example:

'The ConDem government's tactics of attacking the conditions of public workers are highly recessionary.'

The variants of a single gene (its alleles, organisms usually have two alleles but drones have only one) can be:

- dominant (masks the effect of another one)
- recessive (is masked by the effect of another one)
- co-dominant or additive (if you have two different alleles you see an intermediate effect)

The term 'additive' is also used when you have several (or a few) different genes and alleles at each one also show incremental effects on the total.

So, Varroa Sensitive Hygiene alleles (and genes, as there are more than one) have an additive effect on the expression of the trait. I'd bet that the important genes are few in numbers though.

When you have several genes controlling a trait it hardly matters whether individual genes are dominant or recessive as each contributes only a small part of the overall trait. Intermediates abound.

DL, there is genetic variation for such traits. Lines of Scottish bees resistant to AFB were documented in the middle of last century. Acarine was probably an element in the Isle of Wight disease (maybe not the main problem) and the general resistance of the UK bee stock since then probably has a genetic cause. Maybe. Yesterday I was talking to a prominent bee farmer who reports a few lines of evidence that our more native stocks are more susceptible to EFB than are some imported highly bred stocks. If that is true then past exposure to the pathogen has driven resistance in the co-evolving stocks. For our bees this is a new pathogen. I should add that this is speculation, might just be wishful thinking on the part of the person relative this to me.

What reasons do Bailey give for the failure of hygienic breeding? There has been a recent resurgence in interest in this thanks to the efforts of Sussex University. AFB resistance is a bit more complex than hygienic removal, just as Varroa tolerance is more complex than VSH. Early rapid death of an AFB-infected larvae might be important, then the whole thing can be ejected intact without spilling open the load of infective bacterial cells.

DL, I've seen good signs of Varroa tolerance in near-Amm bees myself. I like to think that they may be better at it than some other strains, not the hygienic behaviour (opening brood) but the grooming and biting and carrying out. So in my mind breeding should first focus on stabilising a good strain of bee, preferably Amm, then selecting within that pool for better Varroa tolerance (perhaps a harder one to crack than Amm itself). I wouldn't expect 100% Varroa resistance, just a better level of tolerance.

[Jon]

Jon
I am with you there- but heres the dillema- If you can't breed resistance yourself are you going to abandon your breeding AMM project and buy Primorsky hybrids instead?
If the next generation are not hygenic do you just carry on buying queens ?

I imagine the genes which govern VSH and varroa tolerance are to be found in all bee populations to a greater or lesser extent so resistance could be developed in whatever strain tickles your fancy. The Primorsky strain has a 150 year advantage coexisting with varroa compared to most of the others.

More pupa removal is not necessarily better though, as there have been some reports that colonies which are excessively hygienic are slow to build up. There is probably an optimum level of hygienic behaviour. You don't have to kill every mite for a colony to thrive. The mite population just needs to be kept below a critical number, mainly linked to the level at which viruses will be facilitated, which will vary according to the time of year, the size of the colony and the size of the brood nest.
I have the odd colony which removes hundreds of pupae as soon as the apiguard goes in. I wonder is this liked to hygienic behaviour or is it just an intolerance to thymol?

[The Drone Ranger]

The method used to deal with codling moth (apples) is pheromone traps
malaria mosquito sterile males I think
Dog / cat fleas chemical sterilisation of the laying female
The weakest link in the varroa breeding chain is the first egg she lays is the male if that one fails or is sterile then the varroa population disappears
The magic bullet would be something that kills or sterilises the male varroa.
I hope you are right about breeding solving varroa problems (Gavin, Jon and Jimbo) but I doubt if it will happen in my lifetime.
In a sense varroa tolerance will/could make the problems worse as it seems the spread of virus and the damage to the immune system will continue

[Trog]

Bright yellow plastic strips covered in sticky goo are used to control whitefly in greenhouses. I wonder if something could be inserted in a normal frame (in place of foundation) which had a pheremone attractive to varroa mites and lured them to a sticky end. The bees could be protected by a coarse mesh either side of the trap so that they didn't come into contact with the sticky stuff but still got close enough for piggybacking mites to jump off to investigate.

[The Drone Ranger]

Heat kills them well before the bee larva round about 40'-42'C