Transfer of tau-fluvalinate in honey bee hives: Corie Fulton
The miticide tau-fluvalinate is a synthetic pyrethroid that has been heavily used by beekeepers for over 25 years. This has led to accumulation in wax foundations as well as sublethal effects on honey bees (Apis mellifera) at the adult and larval stage. The objective of this project is to determine if the high levels of tau-fluvalinate accumulated in the wax are capable of transferring into the royal jelly that surrounds the honey bee larvae. The field portion of this project will determine the concentrations of tau-fluvalinate in the larvae and whether or not contaminated wax can be considered as a source. Understanding the fate of tau-fluvalinate can provide guidance for better beekeeping management practices.
The role of neonicotinoid and pyrethroid insecticides exposure in honey bee population declines: Zuyi C. Gooley
Growing concerns have drawn attentions to the impacts of pesticide exposure on pollinators, especially honey bees in the past few years. Neonicotinoid and pyrethroid insecticides exposure is one of the proposed stressors that may cause colony collapse disorder (CCD). A liquid chromatography–triple quadrupole mass spectrometry based analytical method was developed for the detection of seven neonicotinoids and two metabolites in honey bee and pollen samples. Pyrethroid insecticides in honey bee, beeswax, and pollen samples are also detected by gas chromatography mass spectrometry. This project investigates the direct exposure route of honey bees to neonicotinoids in both agriculture and urban areas during foraging, and the direct/indirect exposure route of larvae and pupae to pyrethroids under hive condition. Finally, the fatty acid component and metabolic rate of the honey bees after exposed to the insecticides both in laboratory and field toxicity study was investigated.
Understanding exposure to PCBs using the Tenax method: Federico Sinche
Desorption of PCBs from contaminated sites represents the route of exposure in sediments. The desorbing fraction is the bioavailable compound that the biota will be exposed to, and ultimately the fraction responsible for the biological response. Since the sediment is complex and dynamic system, there are major factors that can influence the desorption of the contaminants, therefore affecting bioavailability. The organic carbon type and content in the sediment are the major factors driving adsorption and desorption of hydrophobic contaminants such as PCBs. Thus, there is a need to understand how the organic carbon, differing in their affinity, is influencing the bioavailability of PCBs. Therefore, the goal of this study is to understand how the organic carbon type and content affects the desorption of PCBs, and consequently the exposure to PCBs. The PCBs have been chosen as model compounds because they are legacy compounds still found in the environment and they vary in their physicochemical properties. The Tenax method was chosen to determine the bioaccessibility of PCBs, which is the amount of compound that can become bioavailable, from sediments. The ultimate goal of this project is to apply the findings to find properties of organic carbon materials that could potentially be applied to bioremediation strategies to restore PCB-contaminated sites with little side effects on the native biota.
Examination of Genetic Distinction and Potential Species Divergence between Resistant and Non-Resistant Hyalella azteca: Haleigh Sever, Andrew Derby
The widespread use of pyrethroids has resulted in unforeseen consequences to wildlife and the environment. Hyalella azteca have been found in areas with known pyrethroid concentrations high enough to be fatal to the organisms in a laboratory setting. This indicates that some populations have developed a resistance to this class of pesticide. Currently, Southern Illinois University maintains two genetically distinct populations of Hyalella, belonging to separate clades: one non-resistant strain with no known mechanisms for pyrethroid resistance, and a field-collected strain that has a genetic mutation that alters the target site of pyrethroids on the voltage-gated sodium channel.
Using Tenax extractions to assess pyrethroid insecticide toxicity in urban sediments: Kara Huff Hartz
Single-point Tenax extractions (SPTEs) have been shown to correlate to the bioaccumulation and toxicity of many hydrophobic organic contaminants in sediments (Lydy et al. 2015). The use of SPTEs provides a rapid and an inexpensive tool that complements bioassays, biosurveys, and exhaustive chemical extractions for sediment quality assessments. In collaboration with the USGS, SPTEs are used to assess the bioaccessibility of pyrethroids, an important class of contaminant in urban sediments in the northeastern United States. The aim of the proposed work is to measure the pyrethroid concentrations in sediments using Tenax extractions, and to quantitatively evaluate their correlation with standard bioassay endpoints. The established relationships between Tenax extractable concentrations and toxicity can then be used to estimate toxicity in future assessments of pyrethroid contamination.
The contribution of detoxification pathways to pyrethroid resistance in Hyalella azteca: Courtney Fung
Pyrethroids are a major insecticide class that includes over 3,500 registered products used in residential settings, agricultural maintenance, and for human and animal disease vector control. Chronic exposure to pyrethroids can result in non-lethal impacts to non-target species, driving evolutionary changes at population levels. Pesticide resistance can be conferred through inheritable mutations resulting in reduced target-site sensitivity or through metabolic-mediated mechanisms. The main objective of the proposed research is to determine what metabolic pathways contribute to pyrethroid resistance in target-site mutation populations of H. azteca. This study will also explore whether these resistance characteristics are maintained in these H. azteca populations over multiple generations when reared in the absence of pyrethroid exposure. It is important to characterize the underlying mechanisms of pesticide resistance to better monitor the occurrence, predict the evolutionary dynamics, and design optimal preventative measures.