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Title: SUPPRESSING MITE REPRODUCTION: SMR AN UPDATE

Author
item Harbo, John
item Harris, Jeffrey

Submitted to: Bee Culture
Publication Type: Popular Publication
Publication Acceptance Date: 3/1/2002
Publication Date: 4/4/2002
Citation: Harbo, J.R., Harris, J.W. 2002. Suppressing Mite Reproduction: SMR an Update. Bee Culture. 130(5):46-48.

Interpretive Summary: Varroa destructor, commonly called the varroa mite, is an external parasite of the honey bee. This mite reproduces in the brood cells of honey bees and will normally kill an unprotected colony of bees within two years. Beekeepers use two miticides to protect their bees, but mites have developed resistance to both chemicals. The long-term solution is to breed bees for resistance to mites. Scientists at the Honey Bee Breeding Genetic & Physiology Laboratory (USDA, Agricultural Research Service) in Baton Rouge, Louisiana, have selected bees that are resistant to this mite. The mechanism of resistance is a trait of the honey bee that suppresses mite reproduction (SMR). This trait prevents female mites from producing progeny. Because SMR is a trait rather than a stock, SMR genes can be added to any population of honey bees by using traditional breeding methods. The goal is to add SMR genes to the US population of bees without replacing the ebees that we now have. Because of a Cooperative Research and Development Agreement (CRADA) between the USDA and a commercial queen breeder, SMR breeder queens (SMR queens mated to SMR drones) may be purchased from Glenn Apiaries in Fallbrook, California at $50 per queen. These breeder queens are a source for SMR genes and will enable commercial bee breeders to add the SMR trait to their stocks of bees.

Technical Abstract: From the honey bee population in the USA, we selected bees that are resistant to Varroa destructor. The mechanism of resistance is suppression of mite reproduction (SMR), a heritable trait of the honey bee that prevents female mites from producing progeny. Because SMR is a trait rather than a stock, SMR genes can be added to any population of honey bees by using traditional breeding techniques. Our goal is to add SMR genes to the US population of bees without losing the genetic diversity and the beekeeping qualities that we now have. Our research showed that honey bee colonies expressed a significant level of mite resistance when they received SMR genes only from their mother. Thus, commercially-produced queens can provide some resistance to varroa when they are free-mated to unselected drones. SMR breeder queens (SMR queens mated to SMR drones) may be purchased from Glenn Apiaries in Fallbrook, California at $50 per queen. .These breeder queens are a source for SMR genes and are not intended for use in honey-producing colonies. Thus, commercial bee breeders can get the SMR trait without having to do the selective breeding work themselves. This does not mean that the breeding work is complete, because bee breeders will need to combine these mite-resistant genes with their existing stock to produce the beekeeping qualities and the mite-resistance that they want.