Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2012
Publication Date: 4/1/2013
Citation: Rinderer, T.E., De Guzman, L.I., Frake, A.M. 2013. Associations of Parameters Related to the Fall of Varroa destructor (Mesostigmata: Varroidae) in Russian and Italian Honey Bee (Hymenoptera: Apidae) Colonies. Journal of Economic Entomology. 106(2):566-575. Interpretive Summary: Further work on selecting honey bees resistant to varroa depends on finding a different measurement of resistance beyond those already used. Ideally, a candidate measurement would be simply made and suitable for use in commercial bee breeding. Mites trapped on colony bottom board traps of Russian and Italian honey bee colonies were classified according to age and injury levels and these measurements and ratios of these measurements were related to the total number of mites in the colonies. Some measurements, most notably the total number of young trapped mites were well correlated to total colony mites. Other measurements, most notably the ratio of older trapped mites to the total number of traped mites and the ratio of number of older trapped mites to the number of younger trapped mites were negatively associated with total colony mites. Two measurements of young mites, taken early and late in the season may be a much less work intensive way to estimate mite population growth and thereby serve as a new selection tool. Likewise, a single measurement of the ratios involving older mites may serve as a way to find colonies that suppress mite population growth and themselves serve as a new selection tool.
Technical Abstract: Varroa destructor (Anderson and Truman) trapped on bottom boards were assessed as indirect measurements of colony mite populations and mite fall in colonies of Russian (RHB) and Italian (I) honey bees using 29 candidate measurements. Measurements included damaged and non-damaged younger mites, damaged and non-damaged older mites, fresh mites and all mites, each as a proportion of total mites in the colonies and as a proportion of all trapped mites or all trapped fresh mites. Regression analyses were used to determine the relationships of these candidate measurements to the number of mites in the colonies. The largest positive regressions were found for trapped younger mites (Y) and trapped fresh mites (F). Measurments of Y and F across time could be used to estimate mite population growth for the purposes of selective breeding. The largest negative regressions with colony mites were observed for: trapped older mites/trapped mites (O/T), trapped older mites/trapped younger mites (O/Y), trapped older adult mites/colony mites (O/C), trapped mites/colony mites (T/C), trapped injured older mites/injured mites (IO/I), trapped injured older mites/colony mites (IO/C), trapped fresh mites/colony mites (F/C) and trapped injured mites/colony mites (I/C). O/T and O/Y are significantly higher for RHB colonies suggesting that they are related to at least some of the mechanisms used by RHB to resist Varroa population growth. O/T and O/Y have strong negative relationships with colony mites for both RHB and I colonies suggesting that both strains possibly could be selected for reduced colony mites using O/T or O/Y.