A new study by scientists from Trinity College Dublin and Dublin City University has raised concerns about the exposure of different species of bees to multiple pesticides in Ireland. The research assessed pesticide residues in crop pollen at 12 sites in Ireland, as well as pollen collected from honeybees and bumblebees at the same sites.

The study’s findings indicate that different species of bees may be exposed differently to pesticides, suggesting that pesticide risk assessments for honeybees may not accurately reflect the risk for other bee species. Researchers found that crop pollen was contaminated with fungicides, honeybee pollen was mainly contaminated with fungicides, and bumblebee pollen was primarily contaminated with neonicotinoid insecticides. The highest number of compounds and most pesticide detections were found in bumblebee pollen.

These findings raise concerns about the widespread exposure of bees to multiple pesticides. The study also highlights the potential toxicity of combining insecticides and fungicides, as previous studies have shown that the combination can be more toxic than each category alone.

Elena Zioga, lead author of the study, expressed concern about the exposure differences between bee species and the presence of neonicotinoids in bumblebee pollen when they were not applied in the sampled fields. This suggests that either neonicotinoids persist at the field edges or bees collect contaminated pollen beyond the sampled fields. The study also revealed that neonicotinoid detection increased with the presence of wildflowers in bumblebee pollen.

The findings of this research are significant because bees play a crucial role in pollination services and maintaining healthy ecosystems. Exposure differences between bee species indicate that using honeybees as a reference for understanding pesticide exposure may not provide a complete picture.

Further research is needed to understand the implications of these findings and explore the effects of pesticide exposure on different bee species.

Source: Science of The Total Environment, DOI: 10.1016/j.scitotenv.2023.166214