Project Number: 6050-21000-016-003-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Mar 1, 2018
End Date: Feb 28, 2023
Honey bee (Apis mellifera) populations in North America and Europe are experiencing high and unsustainable annual losses. Since 2006, most research has focused on understanding causes of mortality of honey bee colonies; i.e., the impact of individual stressors, and the interactions among stressors that lead to colony death. Our approach instead uniquely focuses on honey bees’ natural immune responses (individual immunity) and collective behavioral defenses (social immunity), that contribute to bee health and survivorship. Our ultimate goal is to propagate multiple traits of resistance that can counteract various stressors in managed honey bee populations and thus reduce the need for human intervention and promote agricultural sustainability. One form of individual and social immunity in honey bee colonies is the collection of resins from the environment, and the formation of these resins into a propolis envelope that acts as an important antimicrobial layer within the nest. While a propolis envelope cannot mitigate all colony stressors, our previous research indicates it does benefit individual immunity and reduces some pathogen loads in the colony. This behavioral trait when bred in combination with other traits of social immunity, we hypothesize, can positively impact the health and productivity of honey bee colonies. This proposal has the following three main objectives: 1) Clarify and test gaps in our knowledge about the contribution and mode of action of propolis on honey bee individual immunity, pathogen defense. 2) Test if propolis has a quantifiable impact on improving colony health and productivity in commercial beekeeping operations; and 3) Incorporating the heritable trait of propolis collection in a comprehensive breeding program for honey bee natural defenses.
Objective 1. Determine the role of propolis volatiles, and bees' contact with propolis in the nest, on modulating honey bee immune response and pathogen defense. We will conduct a series of laboratory experiments to test the role of propolis on modulating an immune response in: Obj. 1A) pathogen challenged and unchallenged adult bees; Obj. 1B) challenged larval bees; and Obj. 1C) bee viruses in cell culture, larvae and adults. Objective 2. Quantify the potential benefit of propolis to health and productivity of colonies in a commercial beekeeping operation. This objective will be completed with a commercial beekeeping cooperator. Colonies will be given propolis traps to stimulate resin collection or left as controls and monitored for measures of health (e.g. brood quality, survival, lipid stores) and productivity (e.g. honey production and bee population) over two seasons. Objective 3. Initiate a comprehensive breeding program for colony health, with emphasis on selecting for behavioral mechanisms of social immunity against parasites and pathogens. The goal for this objective is to select for, and provide to beekeepers, lines of bees that are selected for health and survivorship in northern and southern climates. In general, we will be evaluating, wintering, and breeding the stocks in Minnesota, and a separate stock in Baton Rouge. After 3 years, we will collaborate with ND and MN migratory, commercial beekeepers who will help evaluate and breed a portion of the stocks in early spring in SE Texas (in locations where Africanized honey bees are not established) before bringing the colonies back to ND and MN for the summer. This follows the same scheme as Spivak followed to test and disseminate the MN Hygienic line. In this way, we will have colonies that are selected for northern winter survivorship in stationary apiaries, colonies selected for subtropical climates (LA) and colonies that are selected for migratory beekeeping operations that transport colonies between the Upper Midwest and the South/Gulf area. We will select for three behavioral social immunity traits: low mite population growth, hygienic behavior and propolis collection. Additional selection will be done for other commercially desirable traits: honey production, gentleness, wintering success and spring build-up. For the first three years, the colonies will be wintered in our University apiary locations in Minnesota, or at the USDA-ARS lab in Baton Rouge.