Pin killed brood assay

[B+.]

Is anyone performing this test? http://coloss.org/beebook/I/queen-rearing/3/3/4/3?searchterm=pin+

What sort of results are people getting?

 

[Michael Palmer]

I have heard that the pin test isn't as accurate as necessary because the brood cap has been compromised. According to Spivak, the frozen brood test is better.

 

[MuswellMetro]

I have heard that the pin test isn't as accurate as necessary because the brood cap has been compromised. According to Spivak, the frozen brood test is better.

yes LASI Uni of Sussex say the same, the pin test gives a false reading, the frozen test can be done by cutting out a section and putting it in the freezer for 24htrs returning the cut out section back to the frame and seeing what they do with the dead brood

 

[B+.]

the pin test gives a false reading, the frozen test can be done by cutting out a section and putting it in the freezer for 24htrs returning the cut out section back to the frame and seeing what they do with the dead brood

I agree. The pin kill assay is recommended for Europe but I think it has to signal that something is wrong with the pupae. I'm against cutting out sections of brood for the same reason. The pin kill test is probably the less invasive procedure if liquid nitrogen is not available.
For the time being, I'm doing the pin kill test but I see its shortfalls.
Is anyone else doing it?

 

[MuswellMetro]

I agree. The pin kill assay is recommended for Europe but I think it has to signal that something is wrong with the pupae. I'm against cutting out sections of brood for the same reason. The pin kill test is probably the less invasive procedure if liquid nitrogen is not available.
For the time being, I'm doing the pin kill test but I see its shortfalls.
Is anyone else doing it?

i tried it with dry ice but not cold enough to kill all the brood

 

[Gilberdyke John]

I agree. The pin kill assay is recommended for Europe but I think it has to signal that something is wrong with the pupae. I'm against cutting out sections of brood for the same reason. The pin kill test is probably the less invasive procedure if liquid nitrogen is not available.
For the time being, I'm doing the pin kill test but I see its shortfalls.
Is anyone else doing it?

I mentioned the test in the bee health section of the forum recently. When I was shown how to do the test it was stressed that pin insertion should be with a fine pin, held straight and pushed in and out vertically to the comb face to avoid making anything but the smallest hole in the wax. Very difficult to see where you had been without the mask and counting cells.
Since the assay is intended to monitor hygenic behaviour and removal of defective brood then granted the bees are closer than human eyes, they may be identifying a different parameter but the end result is the same i.e. cleaning out the cell.
Not an expert, still just learning about this test

 

[Erichalfbee]

i tried it with dry ice but not cold enough to kill all the brood

Would one of those dimethyl ether wart removal gizmos be cold enough?

 

[B+.]

When I was shown how to do the test it was stressed that pin insertion should be with a fine pin, held straight and pushed in and out vertically to the comb face to avoid making anything but the smallest hole in the wax. Very difficult to see where you had been without the mask and counting cells.
Since the assay is intended to monitor hygenic behaviour and removal of defective brood then granted the bees are closer than human eyes, they may be identifying a different parameter but the end result is the same i.e. cleaning out the cell.
Not an expert, still just learning about this test

I use number 2 entemology pins (stainless steel) as specified in the link above but size 000 would be much finer. You can get them from here http://www.entosphinx.cz/en/ They are flame sterilised between tests.
The mask is easy to make...take a sheet of foundation and a draw 10*10 cell trapezoid on the plastic bag the foundation came in. This can easily be transferred to a card or plywood sheet.

 

[B+.]

Would one of those dimethyl ether wart removal gizmos be cold enough?

Liquid nitrogen boils at a much lower temerature (-195) so it freezes the brood quickly. I am not saying the dimethyl ether wouldn't work though.
You really only need to freeze 100 cells to get a percentage of brood removal although you see photos with huge areas of brood killed (http://coloss.org/beebook/I/queen-rearing/3/3/4/2?searchterm=liquid+nitrogen). I don't think this is necessary or desirable.

 

[Michael Palmer]

I've heard it recommended, when using the pin test, to insert the pin from the opposite side of the comb, leaving the cappings on the test side of the comb undamaged.

 

[B+.]

I've heard it recommended, when using the pin test, to insert the pin from the opposite side of the comb, leaving the cappings on the test side of the comb undamaged.

Thats an interesting approach. Thanks Michael.

 

[B+.]

When I was shown how to do the test it was stressed that pin insertion should be with a fine pin, held straight and pushed in and out vertically to the comb face to avoid making anything but the smallest hole in the wax.

I was careful to pierce the centre of each cell but I think I might have missed the pupa in a few cells. Out of 50 that were pierced, I see all except 7 were uncapped but 3 pupae hadn't been completely removed.
I used a number 2 insect pin

 

[B+.]

I see all except 7 were uncapped

I must have been dehydrated: Of the 50 cells that were peirced, only one wasn't uncapped

 

[BeeJayBee]

Do you think your bees are removing mite damaged brood at the same level as they have with this test?

 

[B+.]

Do you think your bees are removing mite damaged brood at the same level as they have with this test?

In theory, the pin kill assay is one of the tests for hygienic behaviour (http://coloss.org/beebook/I/queen-rearing/3/3/4/startpage#table-7-methods-for). However, I see no evidence that they are removing vast amounts of varroa infested brood. As you can see in the photo, the brood appears to be approximately the same age.
I will know more when I perform the next test (http://coloss.org/beebook/II/tropilaelaps/3/4) in July. However, as I suspect the bees are managing the varroa population at extremely low levels, this test may not reveal anything useful.

 

[BeeJayBee]

Surely, if bees were 'hygienic' they would be actively removing all damaged brood, not just those that have been damaged by varroa?

You're testing for Tropilaelaps ??

 

[B+.]

Surely, if bees were 'hygienic' they would be actively removing all damaged brood, not just those that have been damaged by varroa?

You're testing for Tropilaelaps ??

Thats right. However, I see no evidence of varroa during the active season so I believe the colonies manage the varroa levels themselves. The pin-killed brood results (92%) were quite high but these results are taken three times during the year and averaged.
The alcohol wash assay works for varroa too. Its not just for tropilaelaps. I gave you the wrong link but its the same test http://coloss.org/beebook/II/varroa/4/2/3/1/2/3

 

[B+.]

I did another pin killed brood test on Tuesday. The results were interesting, but not for the obvious reason. First, the results:
No. Partial None Complete %
60 1 4 45 90
61 3 0 47 94
62 8 0 42 84
64 1 5 44 88
66 1 17 32 64 (this colony is only being maintained for testing purposes. It will never be used in breeding)
67 5 8 37 74
68 (information not collected)
69 4 1 45 90
For anyone not familiar with the test, 50 sealed worker cells are pirced with a number 2 entomological pin using a trapezoid mask over the brood that exposes 100 cells. The start and end point of the trapezium are marked with a felt pen, as is the last cell to be pierced.
Ok. I could talk about the hygienic and not so hygienic colonies, but, I think the more interesting point is about the test itself. I shook the bees off the frame to be tested and laid it horizontally on another box before piercing the centre of each cell vertically through the capping down to the midrib.
My feeling is that some cells have been ignored because the pupa wasn't killed (i.e. it may have been missed by the pin). Then you have to ask yourself the question: what are you actually testing? Is it the dead pupa or merely the pierced capping? From what I have read, the bees should detect that something is wrong with the cell, open the capping and remove the pupa. However, I noticed a number of cells that had been pierced but were ignored. This suggests to me that the test is flawed. What do other people think?

 

[B+.]

It seems my numbers are coming out too high. I've been told to reduce the time to 8 hours to get a bigger difference between the most and least hygienic :-(

 

[B+.]

I promised to provide an update when I did the soap wash test (http://coloss.org/beebook/II/varroa/4/2/3/1/2/3) for varroa mites. BeeBreed requires a 30g sample taken in the first week of July so my results are expressed slightly differently to Coloss but the method is exactly the same.

No Weight Mites /10g
60 57.68 9 1.56
61 44.57 10 2.24
62 52.12 4 0.77
64 47.06 9 1.91
66 57.53 23 4.00
67 39.83 10 2.51
68 49.55 28 5.65
69 45.70 11 2.41

Queens 60 & 61 are sisters
Queens 62, 64, 66, 67, 68 & 69 are sisters
They were all mated with drones from daughters of 6-42-58-2011-K on the German island of Neuwerk

Although 62 had the lowest mite count, it only produced 1/3 of the honey crop that 60 did. It will be interesting to see how other breeders scored their siblings when the breeding values are published in February