Preparing for Varroa: How Susceptible Are Australian Honey Bee Stocks?
Honey Bee Breeding, Genetics, and Physiology Research
2011 Annual Report
1a.Objectives (from AD-416)
Provide an assessment of the relative resistance/susceptibility of 7 lines of Australian honey bees in comparison to ARS resistant stock. The project will inform decisions about preparing for Varroa in Australia, including whether to fund an indigenous bee breeding program or to reinstate the importation of queen bees to Australia. The project may lead to the sale of United States queen bees to Australia.
1b.Approach (from AD-416)
In November 2010, in Kansas, 250 commercial colonies will be manipulated to standardize their mite populations. This will be done by.
1)Equalizing colony strength,.
2)Heavily treating colonies with multiple miticides. To obtain Australian stock for evaluation, Australian queen breeders will be asked to provide 20 sister queens reared by their standard procedures. Where possible, queens will be control mated. Each group of 20 sisters will constitute a ‘line’ for the purposes of the study. Queens will be mailed to the University of Sydney where they will be clipped and given a unique tag before shipping.
The Australian queens (n = 20 per line) will be sent to Baton Rouge in March 2011 and introduced to the Varroa-standardized colonies. American queens of three lines (Varroa-Sensitive Hygiene – VSH, Russian and standard U.S. commercial; n = 20 per line) will be introduced simultaneously. Queens will be randomly allocated to colonies. Colonies will be visually inspected in May, July, September and November 2011, and the population of Varroa evaluated for each colony by standard techniques (de Guzman et al. 2007). Evaluations will be performed without knowledge of each queen’s origins (including the U.S. queens). Mean mite population growth will be compared among breeding lines using ANOVA.
This project has now been initiated in the field. Twenty queens of each of seven Australian stocks and twenty queens of each of three control stocks (two positive controls and one negative control) were installed in colonies in July, 2011. Each of the 200 colonies was given an inoculum of about 50 varroa mites and the colonies were sampled to determine levels of varroa mites and tracheal mites. The colonies will be monitored monthly for several parameters: size, presence of queen, levels of varroa mites, levels of Nosema ceranae and evidence of parasitic mite syndrome.