Pollinator diversity and potential exposure routes to insecticides near agricultural fields
Pollinators contribute to up to one-third of the food eaten by humans and are currently experiencing a global decline that may be driven by agricultural practices. To better understand the impact of agriculture on pollinators, the pollinators in agricultural settings must first be identified. A pollinator survey using bee bowls and sweep net sampling was conducted across wild or planted flowering cover preceding corn and in alfalfa surrounded by corn to determine pollinator richness and abundance in highly managed agricultural areas. In total, 1,250 bees comprised of 4 families and 16 genera, 20,841 pollinating Diptera assigned to 6 families, 247 pollinating Coleoptera assigned to 3 families, and 141 Lepidoptera were found. A majority of the bees were solitary and nested in the ground. Insecticides are widely used in agriculture and may move out of the treated field into non-target sources, coming into contact with beneficial insects, such as bees. To determine the risk of insecticide exposure that bees might face when foraging on plants growing along the margins of treated fields, flowers were collected from field margins and analyzed using the QuEChERS method coupled with LS-MS/MS to determine the concentration of non-target uptake of insecticides into flowers. Low concentrations and incidence of neonicotinoid, organophosphate, carbamate, and pyrethroid insecticides were found in non-target flowers along field margins. When the insecticide concentrations were compared with the LD50 values for bees, there appears to be minimal lethal risks through flowers along field margins.
Krupke, Purdue University.
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