Drone trapping & Hygenic testing combined

[Patrick Scannell]

One method of VM drone trapping involves putting frames of frozen/thawed capped drone comb back into hives for the bees to clean out.

Has anyone observed the rate of clean-out as an indicator of hygienic behavior.

Any reason why this would not work?

[NashBeek]

I've read somewhere that this is the way they test for hygenic behavior if I'm not mistaken it was on this Forum

[Patrick Scannell]

True, but normal tests involve a 100 x 100 square, or a small circle of frozen worker brood.

I would be exchanging a whole medium frame of drone brood.

Would the larger scale effect the test?

[adamf]

True, but normal tests involve a 100 x 100 square, or a small circle of frozen worker brood.
I would be exchanging a whole medium frame of drone brood.
Would the larger scale effect the test?

A test's efficacy determines worth. Using a small # of cells to test for
hygienic behavior makes it very easy to calculate % removal. Variance
influencing results (seasonal, location, etc) is much easier to account for
with quantitative result data.

Certainly using a whole frame of drone brood would show if the colony
demonstrated hygienic behavior but how would you standardize "a whole medium
frame of drone brood" to make the test more accurate and conclusive when
comparing colonies: accounting for variance in the test makes the test more
accurate.

I think originally freeze-killed brood hygienic testing used chunks of
frozen brood comb. I can't remember if they were a standard size or if they
also were a set # of cells.

However you perform an evaluation for selecting, your success is determined by
the accuracy of the test; the results should reflect the test, not artifacts of the test.
Hence specific number of cells used in the current hygienic test with liquid N2.

Adam Finkelstein
www.vpqueenbees.com

[Patrick Scannell]

>> how would you standardize "a whole medium
>> frame of drone brood" to make the test more accurate...

Counting cells is out, but perhaps a before and after digi-pic. Perhaps even a computer analysis of cells emptied.
It might compare well, in terms of percentage, to a small sample with a few cells missing.

My goal is to maximize observation per management minute. I'm not trying to challenge the liquid N2 protocol, but I'd rather not go to that time and expense if I can use what I'm already doing.

>> results should reflect the test, not artifacts of the test

Speaking of noise: We notice that defensive behavior is reduced during a heavy flow. Have you noticed if hygienic behavior is also reduced then? Is that something you take into account?

Thanks, Patrick

[adamf]

My goal is to maximize observation per management minute. I'm not trying to challenge the liquid N2 protocol, but I'd rather not go to that time and expense if I can use what I'm already doing.

Hello Patrick,
I understand. The current test protocol (liquid N2 protocol) is less expensive or difficult than you'd think. You may rent from your local Oxygen/Gas supplier a liquid N2 tank, with N2 and dewar to apply the N2 carefully for not that much.
If you go in with your neighbours, the group can spread the cost and knock out all the treatments in one day.

If you're exploring the frozen drone brood method, I'd use less than a comb, and try to standardize on area (since you can roughly calcualte cells per square inch or square mm) of the comb per test. Another thought: would you inadvertantly be selecting for removal of drone brood by using drone comb? Where do most brood diseases occur? In worker brood. Sure VM likes drone brood but the freeze kill test doesn't test for VSH, just Hyg behavior. The two are different. You need to test for both in selecting hardy stock.


Speaking of noise: We notice that defensive behavior is reduced during a heavy flow. Have you noticed if hygienic behavior is also reduced then? Is that something you take into account?

Yes. We try to test twice per year. We time the tests to be before a heavy flow.
The more times you test, the more powerful and meaningful your results become.
Testing takes time and resources. The results are worth it, though!

Adam Finkelstein
www.vpqueenbees.com

[Malcolm]

I used one frame of drone comb to trap mites and had great results. The bees cleaned out the dead drones and the queen went back and filled the frame up again. I know that a full frame is not used in hygenic testing but when I saw my bees clean out an entire frame of dead drone brood I was happy. Not sure if that is what you are asking about but it worked for me.

[JBJ]

Patrick, I think you may be on to something. There may be some variance in the numbers drone cells frame to frame, I but I bet you would notice trends over time and you could eventually end up selecting the same bees that you would with the FKBA. One could select with the whole frame technique and then just for good science compare how they do with the standard test. I also like the idea of incorporating the digi photos for easy comparison.

[JBJ]

Alternatively you could cookie cut the appropriate sized sections out of the comb you remove and install it into your drone frames if you are using the the foundation-less section or half sheet type of drone brood/ mite trapping frame. I know some who just cut it out and toss it in the wax melter, but if were froze then reinstalled in the appropriate sections it would test hyg behavior and give them a start on the new section of drone comb

[Michael Bush]

I'm sure a strong hive should have a frame of dead brood cleaned out in 24 hours. Even a weak hygienic hive will clean out the 3" circle in 24 hours.

[tecumseh]

michael bush writes:
Even a weak hygienic hive will clean out the 3" circle in 24 hours.

tecumseh:
I have recently been reviewing an article by spivak and reuter sent to me by flyman and they suggested the protocol was for 100 cells to be frozen. is he 3" circle equivalent to 100 cells?

is it actually to be expected that even a weak hive (vs say a stout hive) would clean out the same area in the specified 24 hour period?

[beemandan]

Even a weak hygienic hive will clean out the 3" circle in 24 hours.



is it actually to be expected that even a weak hive (vs say a stout hive) would clean out the same area in the specified 24 hour period?

The test, as I’ve seen it conducted, uses, as I recall, about a three inch diameter frozen section of capped worker brood. Strongly hygienic colonies will clean out 100% of the dead pupae within 24 hours. Colony hygienic ability typically ranged from 100% to nearly 0%. I’ve assisted in trials where there had been years of selection for hygienic behavior and yet only a few percent of the colonies tested were strongly hygienic (100% removed). Most of the colonies were substantially lower. Convinced me that the trait is recessive.

[JBJ]

Could it be possible to select for that bees that prefer to clean out infested drone cells first?

This may help prevent the colony from wasting time and resources rearing sub par paracitized drones. Varroa tends to prefer drone brood anyway, so bees that were hard wired to focus their attention there first could be an asset.

It could be interesting to compare worker brood clean out vs drone brood clean out times and model the effects on Varroa population dynamics.

[Velbert]

Hygienic behavior is better when there is a flow going.

[Patrick Scannell]

Hygienic behavior is better when there is a flow going.

Interesting. I would have guessed the opposite.

Can you tell us more? Is this based on your personal observation? What sort of hygienic test do you use?

Thanks!

[Michael Bush]

>is it actually to be expected that even a weak hive (vs say a stout hive) would clean out the same area in the specified 24 hour period?

Marla was asked that at the Utah Beekeeprs meeting two and a half weeks ago and she said yes.

[beemandan]

>is it actually to be expected that even a weak hive (vs say a stout hive) would clean out the same area in the specified 24 hour period?

Marla was asked that at the Utah Beekeeprs meeting two and a half weeks ago and she said yes.

Have I misunderstood something in this dialog? (a not uncommon problem)
Maybe you are referring to colony strength (population) instead of strength of hygienic behavior (as I've interpreted the conversation).
Otherwise, how does she tell the difference between hygienic and non hygienic bees?

[Michael Bush]

>Have I misunderstood something in this dialog? (a not uncommon problem)
Maybe you are referring to colony strength (population) instead of strength of hygienic behavior (as I've interpreted the conversation).

Colony strength is what I'm talking about.

>Otherwise, how does she tell the difference between hygienic and non hygienic bees?

Marla says they have it or they don't. There really isn't any in between. The difference is dramatic and with a three inch circle, it's irrelevant to colony strength.

[Velbert]

Was reading old ABJ and came across the article

and it stands to reasoning, Their Moral is higher they work harder


quote=Patrick Scannell;377663]Interesting. I would have guessed the opposite.

Can you tell us more? Is this based on your personal observation? What sort of hygienic test do you use?

Thanks![/quote]

[Patrick Scannell]

>
Marla says they have it or they don't. There really isn't any in between. The difference is dramatic and with a three inch circle, it's irrelevant to colony strength.


"Expression of hygienic behaviour is also
dependent on colony strength. When hygienic colonies become weak or less
populous the hygienic response is significantly reduced (Spivak and Gilliam
1993)."

I just read this in an Australian study.

[Michael Bush]

I'm sure it is reduced. However Marla was asked this question three weeks ago at the Utah Beekeepers Association meeting and assured everyone that hygienic bees would still clean out a 3" circle in 24 hours regardless of the strength of the hive. I would assume that a weak hive would take a bit longer than that for a full frame.