Project Number: 6413-21000-014-03
Start Date: Sep 27, 2013
End Date: Sep 26, 2018
Objective 1: Validate use of esterase activities as biomarkers for exposure to neonicotinoids: In a recent paper, it was reported that esterase activities toward naphthyl acetate substrates were increased in honey bees following topical application of sublethal concentrations to thiomethoxam. In this objective, an evaluation on the use of these substrates (both as substrates in spectrophotometric assays and stains in electrophoretic gels) as biomarkers for exposure to three neonicotinoids in laboratory assays. In addition, we will compare enzyme activities among bees from differing stocks. Finally, an evaluation on the use of these putative biomarkers to insecticide exposure in field settings by comparing activities in honey bees from insecticide- free and agricultural settings. Objective 2: To evaluate the use of lipofuscins and pteridines in aging bees: Insect compounds, such as lipofuscins and pteridines, have been used with varied success to determine the age of insects. It was examined both compounds using ants as a model of social insects. It was were the first to use lipofuscins to age honey bees. However, the lipofuscin levels were examined in honey bee glands, as opposed to the whole head or body, which is the more common in anaylsis. Since many of these compounds break down quickly in exposed sunlight, we propose that testing the lipofuscin and pteridine levels in whole heads of nurse versus forager bees could provide a useful means of determining approximate age of honey bees. Objective 3: To support studies indicating winter is a stressor that exacerbates the effects of pesticides: This objective will tie into overwintering studies being conducted by the USDA honey bee research laboratory. Studies by the USDA include comparing honey bee health and mortality parameters in sites exposed and not exposed to corn containing neonicotinoid insecticides in Iowa. To further explore this relationship, it was proposed transferring a sampling of colonies both apiairies to a warmer winter climate in Louisiana, prior to the initiation of diapause. The hypothesize that if cold climate is the stressor, then it would not expect to see the same physiological effects in bees overwintering in a warmer climate. Additionally, there will be travel to Iowa on several occasions to participate in the collections of data and samples.