Temporal and spatial patterns of systemic insecticides in avian and insect pollinators and flowers in western Canada (2018, 2019)

Abstract

Increasing awareness of the global impact of systemic insecticides on ecosystems prompted us to examine the spatial and temporal contamination of avian and insect pollinators and their floral resources within blueberry growing seasons in the Fraser River valley in BC, Canada where a mixture of urban, suburban and agricultural areas exist. We measured six systemic current-use insecticides in flowers, hummingbirds, honey bee (Apis mellifera) nectar, and honey sampled in April through July, 2018 and 2019, at 13 sites located 0.16 to 22.8 km from conventionally sprayed blueberry fields (CSBF). Across this landscape, there was widespread contamination in all of these media with mixtures of insecticides detected throughout the study period. The number of compounds detected in wildlife significantly increased with proximity to CSBFs. The mean concentrations of insecticides were highest in media collected near to CSBFs however there were no significant spatial or temporal patterns except that there were significantly higher concentrations of flupyradifurone (FPF) in flowers in 2018. The results indicate substantial pesticide exposure continues throughout the growing season and the Fraser valley in flowers, hummingbirds, and bees. The imidacloprid concentrations detected exceeded sublethal effect levels in honey bees. The combined concentrations and chronic presence of neonicotinoids are of concern for hummingbird health. However, the butenolide, flupyradifurone, was detected at the highest concentrations in all media but the effect level in wildlife is unknown. Concentration of 10.7 ng/ml FPF in hummingbirds was an order of magnitude above the maximum imidacloprid detected (0.43 ng/ml).

Keywords

• Hummingbirds
• Honey bee honey
• Nectar
• Flowers
• Neonicotinoid
• Butenolide