Re: Varroa tolerant queen breeders for 2012
Adamf, My statement was made based on 20 years of seeking and raising various types of varroa tolerant bees, not just from reading articles on the internet. In the early years from the roughly 1990 invasion of Varroa into the U.S., the major resistance mechanism was breaks in brood rearing. Any way you slice it, those breaks wound up cutting honey production.
Along the way, a few colonies were found that were naturally tolerant to varroa without the brood breaks. In retrospect, these were either highly hygienic or else mite mauling bees. Most feral bees were wiped out. Selection within the pool of survivors is gradually increasing the mite tolerance traits in our feral population.
When the Russian queens were brought in, researchers at first called the tolerant genetics "SMR" because they did not understand the mechanisms involved. These bees exhibit very high levels of mite tolerance, but if line bred too closely, they exhibit traits like uncapping and removing even healthy brood. This trait seems to be a case of a little bit is good, but too much is a problem. If you are not familiar with this aspect of VSH, I suggest you check with Glenn Apiaries, they deal with it on a regular basis.
When the Africanized bees arrived, we got a look at another tolerance mechanism. They tend to maul mites with their mandibles. This trait is present in our feral bees, but at an extremely low level. It does not have a direct effect on honey production, but these bees tend to be more aggressive than most beekeepers would want to deal with.
That gets us to the essence of my statement. When you consider all the queen breeders in the U.S., less than 10% are raising highly varroa tolerant queens. That number is increasing rapidly as breeder queens with high levels of mite tolerance become more common. The problem I see is that these tolerant queens are based almost entirely on the VSH trait. This trait has known problems when concentrated. As I stated, brood production is reduced and honey production is reduced too. That you actively select for both production and tolerance is the path we should be going forward, but I would bet a dollar that you either don't actually screen your breeder queens to see which trait they are exhibiting or else don't actively seek other traits like mite mauling in your breeding lines.
My reason for starting this thread is because we are at the tipping point where bees in the U.S. are finally going to be mostly varroa tolerant. I would like to see more effort made to increase the mite mauling trait in our bees. That is the one trait you don't mention selecting for and arguably it is the trait most needed to finally get away from using chemicals.
I have not treated my bees since 2005. They are healthy and productive. My only significant problem is that they are not genetically diverse enough for my liking. I would love to see an importation of Lamarckii, Saharensis, Cypria, Carnica, and Jemenitica that had been carefully screened for hygienic behavior. That would go a long way toward increasing genetic diversity in our bees.
DarJones - 44 years, 10 colonies (max 40), sideliner, treatment free since 2005, 11 frame broodnest, small cell