Suppressed mite reproduction

[source linked above]

Suppressed mite reproduction SMR, (now renamed VSH, varroa sensitive hygiene) is the latest trait we have to work with. It holds great promise in solving the varroa problem, but it’s too early to say exactly how and why it works. There is something about the bees that carry the trait that inhibits the varroa mites from reproducing normally. Some of the mites don’t lay any eggs. Others lay eggs too late in the cycle to mature. And some will lay only a male egg. Still other mites get caught between the bee larva cocoon and the cell wall and die before they can lay any eggs. Whether all these are effects are one trait or several is still unknown. Also we don’t know how many genes are involved. Fortunately, it’s not necessary to know all these details to select for and utilize the trait.