video: bees removing larvae with varroa

[Stromnessbees]

I found this video which shows bees removing larvae (or should I write pupae?) infected with varroa. The page belongs to a Germany-wide association of beekeepers which work together to breed varroa-tolerant bees. They have very strict selection criteria and isolated mating sites, and they swap queens of successful colonies amongst each other.

http://www.toleranzzucht.de/home/video/

I found it very cunning how the mite still got away!
It also shows the needle-test which is described on this page (in English):

http://www.beekeeping.com/articles/u...port/index.htm

Doris

[Jimbo]

Hi Doris,

Great video. I noticed the beekeepers were not wearing any protective clothing. When I went on a visit to beekeepers in Denmark the only people wearing protection were the Scottish visitors. It was after this visit that got me started in trying to improve my bees. I always wanted bees that were gentle and did not sting me. I tried to breed this gentle trait into my colonies for years but soon discovered that it would be difficult with hybrid bees. The bees in Demark and Germany are pure breeds and also bred to be gentle to handle. On a visit to Ireland I also saw gentle Galtee black bees.
Back in 2006 John Tyler from Largs noticed in some of his 70 colonies the varroa had been damaged by his bees. The varroa had cuts and bashed outer shells. He tried to breed from these colonies but I don't know how he got on. The point is how many of us (who have varroa) when doing a varroa count actually check the varroa for signs of damage. It may be we have colonies of bees trying to be varroa resistant but don't actually know it.
There is a BIBBA group I think in Cornwall also looking at varroa resistant bees.

Jimbo

[Jon]

I think Gavin has pictures of varroa damaged by bees.

[Jimbo]

Hi Jon,

I have seen pictures of damaged varroa but can't remember where I saw them (the memory is not as good as it used to be!). If Gavin or anybody else has pictures of damaged varroa it may be of interest to post them on this site for people to know what to look for when counting the varroa.

Jimbo

[gavin]

I'm not sure if I do!

There was this:

http://www.scottishferals.org.uk/

We took it so far, but my attempt to try these bees at my apiary didn't work out. One colony was hygienic (cleared out infested cells) but didn't keep on top of the numbers of Varroa and seemed to drop undamaged mites. Another colony did better, and the one that impressed me most was one of my own stocks that I was using to multiply Varroa for tests - it let them build up but them held them in check. Damaged mites have legs or antennae amputated, or a big hefty dent in the carapace. I know a man who watches his bees doing this.

However the whole business is complex. Hygienic behaviour is part of the picture, grooming is part of the picture, damaging mites is part of it, and there may be other mechanisms too.

Grooming is thought to be a learned or induced behaviour, less directly influenced by genetics but genetics must be a part of it. My feeling is that many colonies can do this. May be the same thing as biting and damaging. The hygienic trait is also there in some colonies, probably the VSH trait discovered by John Harbo and Jeff Harris that Rodger Dewhurst and James Kilty were working on.

Eric in one of his pieces in the latest SB mentions the suppression of mite reproduction. There is no evidence for this and it seems to be just that VSH bees leave sterile mites alone and excavate fertile ones, giving the impression that they have somehow been sterilised.

Definitely scope for selecting partial Varroa tolerance (for those who have enough colonies to do this!).

G.

VSH? Varroa Sensitive Hygiene. Many bees are capable of spotting some problems with brood and removing the affected brood. VSH bees can detect most (>95%) of worker cells that have a reproducing mite in residence within 5 days, or something like that. Normally hygienic bees will get some of them but not all.

Later thought: This VSH trait can work on its own even if adult mites escape. Continual interruption of the brood cycle means that mites can't build up, and eventually the mites run out of steam. However give them some drone brood and things change - discovery and removal of mites is harder and reproduction rate higher. Some A. cerana entomb infested drone by strengthening the cappings, but there is no sign that A. mellifera does this. But couple a strongly VSH colony with a propensity to repeatedly groom and bite parasites and you may have something good enough.

[Stromnessbees]

Hi Gavin

the one that impressed me most was one of my own stocks that I was using to multiply Varroa for tests

... is this by any chance one of your surviving colonies?

Doris

[gavin]

Hi Doris

The colony in that box went queenless and was finally requeened from a sister line. It is now down to one seam of bees. The sister line is still doing well enough.

The high Varroa populations until late summer couldn't have been good for my bees, and for now I think my priorities are going to be breeding healthy bees without Varroa pressure rather than breeding Varroa again.

best wishes

G.

[Neils]

Fascinating video, I've noticed my bees doing something similar during inspections this year though I'd obviously not chalk it down to VSH at this stage. The pin test though is very interesting as it does appear something practical that can be tried out by your average layman (ie me)

[Jimbo]

Hi Nellie,

I have been told that another way to do the test is to freeze the cells in situ which is a lot quicker than pushing a pin into cells 100 times. I have been told if you can get dry ice pellets put them onto the area for a few minutes. As most people will not have access to dry ice you could possibly freeze the area with a spray that plumbers use to freeze pipes. I have also seen a spray in the chemist that freezes warts that might work.
I must add that I have never tried any of the above as I try my hardest to produce brood and not kill it!

Jimbo

[Neils]

Nice Idea Jimbo, I was favouring the pin test as it looked a bit less kerfuffle given the distances involved going to and from the apiary, not to mention cutting out and re-applying the comb to take it home and freeze, I hadn't considered using a wart spray type affair.

I suppose it also wouldn't be too much trouble, once you've made the pattern to use the offcut to make a push in needle widget to do them all at once.