Submitted to: Apiculture and Social Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 22, 2001
Publication Date: December 1, 2001
Citation: HARBO, J.R., HARRIS, J.W., RESISTANCE TO VARROA DESTRUCTOR (MESOSTIGMATA: VARROIDAE) WHEN MITE-RESISTANT QUEEN HONEY BEES (HYMENOPTERA: APIDAE) WERE FREE-MATED WITH UNSELECTED DRONES, JOURNAL OF ECONOMIC ENTOMOLOGY, 2001, VOL. 94, pgs. 1319-1323, EDITION #6. Interpretive Summary: Varroa destructor, an external parasite of the honey bee, has been the number one beekeeping problem in the USA since 1987. These mites feed on the blood of honey bees and a mite population will continue to grow until it kills the colony. We have found a trait of the honey bee that prevents the mites from reproducing and therefore provides genetic resistance to these mites. We call this trait suppression of mite reproduction or SMR. The purpose of this study was to see if beekeepers could benefit from the commercial production of queens that have this trait. Commercial queen producers do not control the mating of queens, so if we supply them with breeding stock, the resulting queens would be free-mated and a colony produced by one of these queens would have only half as many of the mite-resistant genes as the parent colony had. From field tests in Baton Rouge, we learned that colonies with these commercially-produced SMR queens had fewer mites at the end of a 4-month test period than did control colonies that did not have the SMR trait. Therefore, beekeepers can derive some immediate benefit from mite-resistant queens that have been free-mated to unselected drones. The production and distribution of mite-resistant queens from many commercial sources may be an effective way to insert mite-resistant genes into our nationwide population of honey bees.
Technical Abstract: This test compared the growth of mite populations in colonies of honey bees that each received queens with various levels of breeding for resistance to Varroa destructor: (1) resistant, queens selected for suppression of mite reproduction and artificially inseminated in Baton Rouge with drones from similarly selected stocks; (2) resistant x control, resistant queens, as above, produced and free mated to unselected drones by one of four commercial queen producers; and (3) control, commercial queens chosen by the same 4 queen producers and free mated as above. All colonies started the test with about 0.9 kg of bees that were naturally infested with about 650 mites. At the end of the 115 d test period, the resistant colonies (n = 12) had 19 +- 18 (mean +- SD) mites, resistant x control (n = 23) had 424 +- 422, and the controls (n = 23) had 834 +- 755. The percentage of mite-infested brood that produced no progeny was 100 +- 0% (mean +- SD), 58 8+- 24%, and 40 +- 27% in these treatment groups, respectively. All means were different at the 0.05 level. These results suggest that beekeepers can derive some immediate benefit from mite-resistant queens that have been free-mated to unselected drones. The production and distribution of these free-mated queens from many commercial sources may be an effective way to insert beneficial genes into our commercial population of honey bees without losing the genetic diversity of that population.