(an interesting story from allen dick)
Word is, in a nutshell, that SMR bees are actually hygienic bees, but with an important difference.
SMR bees perform right up there with the HYG strains in standard HYG tests, however, hygienic abilities observed in bees selected for SMR extend beyond simply detecting and removing dead brood. In addition to doing equally well as HYG in detecting and removing dead brood, SMR bees are able to detect, uncap, and remove foundress varroa mites that are laying eggs and reproducing in cells.
This uncapping and removal liberates the foundress, interrupts her reproductive work, and prematurely exposes the undeveloped offspring, resulting in the death of the daughters. The foundress may then enter another cell, but, if she tries to reproduce there, the cycle repeats. Thus SMR greatly reduces mite reproduction, and mites die of old age or accidents without replacing themselves.
The wrinkle is that these bees seem to be much less inclined to uncap and remove foundress mites in sealed brood that are -- for whatever reason -- not laying eggs, and in any hive with varroa, there will be a considerable percentage of mites that non-reproductive, but which are just sitting out the dance in sealed in cells with the pupae.
These non-reproductive mites enter the cell, stay the duration of the capping period, then emerge with the bee.
This subtle fact -- that SMR bees quickly and efficiently remove reproducing mites in brood, but ignore non-reproductive mites in sealed brood --initially escaped researchers, and obscured the strong similarity between SMR and HYG.
Researchers finding and observing the varroa in the sealed brood of such colonies concluded (understandably) that the bees were causing mite non-reproduction, rather than realising that the bees had already located, uncapped and pulled out most of the reproducing foundresses, leaving only the non-reproducing mites. After all, they would pull a frame of brood, brush off the bees, then go to the lab and look at the brood and mites in cells under magnification. Sure there were a few empty cells, but there always are.
They observed that a high percentage of foundress mites discovered in sealed brood were non-reproducing, and that there were fewer mites -- as a percentage of total mite load --in brood than expected. They bred for this characteristic, and actually wound up with an hygienic bee, but one with special abilities -- the ability to sniff out and eject reproducing varroa mites in sealed brood.
Current work -- if I understand correctly -- seems to indicate that SMR and existing HYG cross well, and that the SMR characteristic can be transmitted relatively easily to current HYG stock, so we may see some interesting things in the near future. A name change for SMR may be in the offing as well.
FWIW, preliminary DNA work _seems_ to indicate that just two genes are associated with SMR, but when asked if they are the same genes that are associated with HYG, the answer from those working hard on this problem, seems to be that no one knows yet, and that there is likely more to the whole picture it than just two genes.
I might mention that Dee has been saying for a long time that Lusbys' bees remove varroa foundresses, and that this is a major mechanism in the Lusby success. I think -- correct me if I am wrong -- that she also believes that using small cells (4.9) encourages that trait. I have heard others, here and there, some with small cell and some with ordinary cells, observing varroa removal, too.
This new(?) information is especially interesting for those of us who think we can breed bees by looking at natural drop boards and rejecting hives with big drops. It is not that simple. We could be rejecting the best varroa fighters, using that criterion, if they are, at that moment, combating an infestation originating outside the hive. Observations over a longer period are necessary to get an understanding. (Again, credit to Dee for that).
(Varroa Killer)
To my mind, one of the most interesting bits of info I gleaned at the AHPA meeting is that the Carl Hayden lab has been testing 2-Heptanone as a potential bee repellent.
It seems that 2-Heptanone kills varroa without affecting the bees noticeably. 2-Heptanone is a food additive (blue cheese flavour/smell ingredient) and so should be acceptable in beehives. The problem is that it is very volatile and would be "gone in 60 seconds". Therefore the ARS is working on a micro-encapsulation process to form time-release strips that can be laid on a top bar. The strips are being designed to last the duration of treatment period, but be fully consumed by the bees by the end of that time, thus eliminating the need to go back to remove anything. Several herbal products are being tested and formulated for use against AFB as well.
They were testing 2-Heptanone as a bee repellent to mix with insecticides to keep bees from visiting freshly sprayed areas, when they discovered 2-Heptanone was killing varroa.
Topic: SMR Bee's (Read 3364 times)