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United States Department of Agriculture

Agricultural Research Service

Research Project: Determining the Impacts of Pesticide and Nutrition-Induced Stress on Honey Bee Colony Growth and Survival

Location: Honey Bee Research

Project Number: 2022-21000-018-00
Project Type: Appropriated

Start Date: Feb 07, 2014
End Date: Feb 06, 2019

Honey bees obtain their nutrients from pollen and nectar, and are thus vulnerable in a landscape with increased exposure to agrochemicals and decreased pollen diversity. Agrochemical use has been increasing, but we do not yet have a comprehensive understanding of the effects of acute and chronic exposure to these compounds on colony survivorship or nutritional status. The objectives of this project are to evaluate pesticide, fungicide and miticide exposure and nutritional stress with respect to bee nutrition, worker-queen interactions, pheromone profiles, queen retention, colony growth and forager activity. Information from studies on pesticide exposure and the nutritional value of pollen and bee bread will help determine experimental treatments for work on worker nutritional status, queen survivorship and oviposition, and worker-queen interactions. The impact of the effects of pesticide exposure on the colony level will be evaluated by continuously monitoring hive weight, temperature and forager activity in row crop agriculture and in nut and fruit pollination. The role of nutrition on Varroa population growth and on colony recovery will also be examined. Objective 1: Determine the nutritional composition of pollen before and after conversion to bee bread and determine the effects of pesticide- and nutritional-stress on worker bees and on colony population growth and survival. Subobjective 1A: Quantify the nutritional composition of pollen and bee bread according to the time of year when the pollen is collected. Subobjective 1B: Determine if worker hemolymph protein levels, hypopharyngeal gland development, and virus titers differ depending on pollen source, nutritional composition and time of year. Subobjective 1C: Determine the effects of pollen contamination with fungicides and mite treatments alone or in combination on worker hemolymph protein levels, hypopharyngeal gland development, and virus titers. Subobjective 1D: Examine the effects of exposure to pesticide-treated row crops on colony growth, nutritional status, phenology and foraging activity. Subobjective 1E: Evaluate the effects of participation in commercial nut and fruit pollination on colony growth, activity and survivorship. Objective 2: Determine the effects of nutritional stress on Varroa parasitism success and mite population growth in colonies. Subobjective 2A: Evaluate the effects of nutrition and pollen source on Varroa reproductive success. Subobjective 2B: Assess the nutritional recovery time for colonies after infestation by Varroa. Objective 3: Identify pesticide stress factors influencing worker-queen interactions, pheromone production, queen supersedure, and successful queen replacement. Subobjective 3A: Evaluate the effects of neonicotinoid exposure on queen pheromone production, queen supersedure and replacement, and worker-queen interactions. Subobjective 3B: Evaluate the effects of neonicotinoid exposure on colony overwintering and almond pollination.

Subobjective 1A: Determine whether pollens collected by bees in the spring and summer differ in nutritional composition from pollens collected in the fall when colonies are preparing for overwintering. The pollen and bee bread will be collected from two general sources: 1) colonies that are open foraging on undefined pollen sources throughout the year and 2) colonies foraging on specific plants we provide. Subobjective 1B: Evaluate the effects of pollen sources on worker and larval hemolymph protein and lipids, on hypopharyngeal glands, and on virus and Nosema levels in workers. Subobjective 1C: Evaluate the effects of pollen contamination with the fungicide Pristine®, with and without the miticide Amitraz, on colony health and worker nutritional status during spring, summer and fall using uncontaminated pollen collected during each season. The experiments will have 4 treatments: pollen only, pollen fed to colonies with Amitraz strips, pollen with added fungicide, and pollen with added fungicide in colonies with Amitraz strips. Subobjective 1D: 1) Develop methods to link continuous weight and temperature data to hive phenology; and 2) conduct longitudinal and factorial field experiments to examine the effects of pesticide exposure and nutritional effects on changes in colony weight, internal temperature, forager activity and nutritional status. Subobjective 1E: Examine the effects of participation in a commercial pollination event, including exposure to fungicides and/ or pesticides, on bee colony growth and activity. Honey bee colonies will be established, thoroughly evaluated, and monitored continuously with electronic scales and temperature sensors prior to and during deployment to either 1) orchards likely to be treated with agrochemicals; or 2) orchards not likely to be treated. Subobjective 2A: Examine whether Varroa reproductive success is affected the nutritional value of pollen and by bee nutritional stress by exposing bees to pollens of different nutritional value, and to artificial pollen dearth through the use of pollen traps, and monitoring varroa populations. Subobjective 2B: Evaluate the effects of bee bread, made from pollens collected during spring, summer, or fall, and of supplemental protein diet, on worker hemolymph protein concentrations following parasitism by Varroa, in addition to field experiments to examine colony recovery from Varroa infestation. Subobjective 3A: Examine the effects of neonicotinoid exposure on pheromone-mediated interactions in bee colonies, with a focus on: Pheromone emissions (whole colony (E)-ß-ocimene, EO, BEP, QMP, and queen (E)-ß-ocimene), nutritional status (bee and food nutrient contents, bee mass, food stores cells), queen performance (queen-worker interactions and retention), forager effort, pesticide residues, and colony performance Subobjective 3B: Examine the effects of pesticide exposure on colony overwintering and almond pollination 1) during fall production of winter bees and 2) when colonies produce replacement bees for winter bees during the first annual forage by monitoring compounds listed in Subobj. 3A.

Last Modified: 7/26/2016
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