Grantee Research Project Results
Effects of Neonicotinyl Insecticides on Honey Bee and Bumblebee Fecundity and SurvivalEPA Grant Number: FP917374
Title: Effects of Neonicotinyl Insecticides on Honey Bee and Bumblebee Fecundity and Survival
Investigators: Wu, Judy Y
Institution: Saint Marys University of Minnesota
EPA Project Officer: Lee, Sonja
Project Period: August 1, 2011 through July 31, 2014
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2011) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Pesticides and Toxic Substances
The main objective of this project is to determine if and how neonicotinyl insecticide exposure contributes to honey bee and bumblebee colony decline. To do this, three research questions or focuses will be addressed. The first investigates how results obtained from laboratory bioassays, used to determine potential non-target risk, compare to responses from relevant field exposures. The second question will evaluate the over-wintering and reproductive success of honey bee and bumblebee queens exposed at known field-relevant concentrations of neonicotinoids. The third question will investigate possible physiological mechanisms responsible for observed behavioral effects of neonicotinyl insecticide exposure on bees reported in previous studies. The results of this project will be an important contribution and will improve the understanding of the effects of neonicotinyl insecticides on honey bee and bumblebee health, reproduction and survival.
The first stage is to complete several standard laboratory bioassays in which bees are individually fed a standard amount, 10 microliters, of test solution for each dose. A second set of bioassays will be completed in exactly the same manner except each bee will be fed 50 microliters of a test solution. Honey bees can collect 30 to 80 microliters of nectar while foraging, therefore comparing the responses in bees exposed at laboratory versus field relevant doses will improve the understanding of how accurate laboratory bioassays are in determining exposure risk to bees in the field. The second stage of this project is to determine field relevant exposure rates to use in experiments. This will be completed by treating plots of canola plants at various rates and analyzing the residue levels found in pollen and nectar of the treated plants. The experiments examining overwintering and reproductive success of honey bee and bumblebee queens will use the relevant field doses determined by chemical analysis from pollen and nectar collected from treated plants.
Comparisons between bioassays using laboratory standard and field relevant doses will improve the understanding of the effects of varying doses and concentrations of neonicotinoid exposure and may help elucidate discrepancies among reported results in various studies examining effects of neonicotinyl insecticides on bees. Using field relevant concentrations, determined by chemical analysis of nectar and pollen from treated plants, doses will provide more realistic responses to experiments and will strengthen the findings.
Potential to Further Environmental/ Human Health Protection
These results will determine possible sub-lethal effects of neonicotinyl insecticides on honey bee and bumblebee reproduction and diapause previously not studied. These results also will be important in assessing the degree to which neonicotinyl insecticide exposure affects queen bee health, colony survival and whether current methods of risk assessment are sufficient in protecting pollinators.