ARS | Publication request: A SURVEY OF TRACHEAL MITE RESISTANCE LEVELS IN U.S. COMMERCIAL QUEEN BREEDER COLONIES

Submitted to: American Bee Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 7, 2000
Publication Date: May 1, 2000
Citation: DANKA, R.G., VILLA, J.D., A SURVEY OF TRACHEAL MITE RESISTANCE LEVELS IN U.S. COMMERCIAL QUEEN BREEDER COLONIES, AMERICAN BEE JOURNAL, 2000, VOL. 140, pgs. 405-407, EDITION #5.

Interpretive Summary: Tracheal mites (Acarapis woodi) are internal parasites of honey bees that are a vexing problem for U.S. beekeepers. The problem can be solved by using honey bee stocks that have genetic resistance to these mites. For bee breeders, identifying resistant and susceptible colonies in breeding stock is a key to success in breeding efforts. Our objectives were to estimate the range of resistance that exists in commercial breeder colonies, and enable participating queen breeders to improve the quality of their stock. Eight commercial queen producers from five states submitted bees to be evaluated for relative resistance. Of the 83 breeder colonies we tested, about two-thirds were resistant and one-fourth were susceptible. Three queen producers had breeder colonies that were relatively uniformly resistant. The other five queen producers had breeder colonies that were variable and of which 40% were susceptible. These susceptible colonies were eeliminated from the breeding population based on the test results. Althoug the majority of colonies we tested had useful resistance to tracheal mites, some breeder colonies were highly susceptible. Queens propagated from such colonies and then widely distributed through commercial sales may be contributing to the lingering tracheal mite problems in the USA. Further testing and selection would diminish the number of susceptible colonies in the breeding population.

Technical Abstract: Eight commercial queen producers from five states submitted brood from 6 to 19 breeder colonies each so that emerging bees could be evaluated for relative resistance to tracheal mites. Young, uninfested bees from each colony of an individual queen producer, and also from colonies of two standard stocks (one known to be resistant to tracheal mites and one known to be susceptible), were simultaneously exposed to mites in infested colonies, then retrieved and dissected to determine resultant mite infestations. Results for the breeder colonies were adjusted to the average results of the resistant and susceptible standards with which they were tested. The 83 breeder colonies varied greatly in their response to tracheal mites. About two-thirds were statistically similar to the resistant standard and one-fourth were similar to the susceptible standard. Three queen producers had breeder colonies that were relatively uniformly resistant; 30 of 31 colonies were classified as resistant. The other five queen producers had breeder colonies that were very variable and of which 40% were susceptible. These susceptible colonies were eliminated from the breeding population based on the test results.