Project Number: 6050-21000-016-000-D
Project Type: In-House Appropriated
Start Date: Mar 5, 2020
End Date: Mar 4, 2025
Meaningful contributions towards enhancing the economic value of the nation’s commercially managed honey bee populations can be achieved through identifying, characterizing and breeding more robust bees. The proposed 5-year plan focuses on synergistic projects (Fig.1) that capitalize on genetic and breeding approaches with the following objectives: Objective 1: Identify and evaluate traits, strains and stocks for improved honey bee health. Sub-objective 1A: Understand the mechanisms of viral transmission and resistance or tolerance to reduce impacts of infection through selective breeding. Sub-objective 1B: Evaluate genotype-dependent nutrient efficiency in commercial honey bee stocks. Sub-objective 1C: Evaluate genotype-dependent nutritional stress resistance in commercial honey bee stocks. Sub-objective 1D: Characterize the impact of genetically based variation in vitellogenin -- the primary honey bee storage protein with roles in immune function, oxidative stress resistance and lifespan -- on colony and reproductive (queen and drone) health and productivity. Sub-objective 1E: Identify and characterize genetic and physiological mechanisms of pesticide resistance in honey bees. Objective 2: Characterize genetic, physiological and behavioral aspects of important traits, strains and stocks. Sub-objective 2A: Examine patterns of genetic diversity and loci under selection in United States honey bee breeding populations, with a focus on stocks exhibiting high VSH activity. Sub-objective 2B: Elucidate the interaction between individual and social immune defenses. Sub-objective 2C: Improve understanding of the biology of the VSH trait. Objective 3: Conduct traditional breeding or marker-assisted selection of honey bees. Sub-objective 3A: Ascertain the effect of inbreeding on genetic diversity across the honey bee genome to support breeding and maintaining health of breeding populations. Sub-objective 3B. Assess genetic diversity at the sex locus of commercial breeding populations of honey bee stocks developed by USDA, ARS HBBGPL. Sub-objective 3C: Determine the potential usefulness of a simple hygiene assay as a selection tool to predict VSH-based mite resistance in honey bee colonies. Objective 4: Develop management tools for improving honey bee health. Sub-objective 4A: Identify and characterize genetic differences in honey bee response to introduced dsRNA, and test for correlations with viral infection and resistance. Sub-objective 4B: Improve understanding of the flight activity of Russian honey bees during almond pollination. Sub-objective 4C: Evaluate the efficacy of a microalgae platform to improve honey bee colony performance and health. Sub-objective 4D: Determine the sublethal effects of fungicides on honey bee health. Sub-objective 4E: Assess sustainability of Varroa control methods.
Honey bee health is threatened by parasites, pathogens, poor nutrition and pesticides. Breeding robust bees with improved resistance (or tolerance) to threats could mitigate these problems. The project combines diverse approaches and techniques to seek and exploit genotype-dependent responses of honey bees to biotic-, nutrition- and pesticide-related stressors. The project improves understanding of genetic diversity across U.S. commercial stocks, enabling both marker-assisted selection and conservation of genetic resources. This will enhance the effectiveness of contemporary breeding programs. Varroa destructor (hereafter, Varroa) is the greatest threat to bee health worldwide. The project builds on past successes by improving selection efficiency for resistance to Varroa and for elevated colony performance, promoting adoption by beekeepers. Investigations target relationships between genetic diversity across stocks, immune responses, and treatment effectiveness against Varroa, viruses, and other related biotic threats. This is critical because of recent beekeeper reports of miticide- (amitraz-) resistant Varroa. Given the threat from Varroa, the plan outlines novel (Sub-objectives 2B, 4A) and continuing (Sub-objectives 2C, 3C, 4B) research on breeding and management related to Varroa-resistant honey bees. In addition, we also initiate a suite of new studies addressing the negative impact of stressors whose prevalence has increased across managed honey bees in the past decade. These studies will assess differences in genotype-dependent responses to viruses and other pathogens (Sub-objectives 1A, 2B), poor nutrition (Sub-objectives 1B, 1C, 1D, 4C), and pesticides (Sub-objectives 1E, 4D, 4E). The project seeks to improve nutrient assimilation efficiency through breeding. Similarly, genotype-dependent differences in bee responses to pesticides will be targeted for breeding less susceptible bees and reducing queen failures. Biomarkers identified as useful for signaling emerging health threats will be verified, benefitting beekeepers by allowing for rapid corrective intervention. These approaches will capitalize on novel sequencing technologies to examine many of these issues at a higher level of resolution across the honey bee genome (Sub-objectives 2A, 3A, 3B).