Assessment of the vulnerability to pesticide exposures across bee species

Authors: SCHMOLKE, AMELIE - Waterborne Environmental; GALIC, NIKA - Syngenta Crop Protection; FEKEN, MAX - Syngenta Crop Protection; THOMPSON, HELEN - Jealott Hill International Research; SGOLASTRA, FABIO - University Of Bologna; Pitts Singer, Theresa; ELSTON, CHARLOTTE - Jealott Hill International Research; PAMMINGER, TOBIAS - Basf, Germany; HINAREJOS, SILVIA - Sumitomo Chemical Australia

Submitted to: Environmental Toxicology and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2021
Publication Date: 7/1/2021
Citation: Schmolke, A., Galic, N., Feken, M., Thompson, H., Sgolastra, F., Pitts Singer, T., Elston, C., Pamminger, T., Hinarejos, S. 2021. Assessment of the vulnerability to pesticide exposures across bee species. Environmental Toxicology and Chemistry. 40(9):2640-2651. https://doi.org/10.1002/etc.5150.
DOI: https://doi.org/10.1002/etc.5150

Interpretive Summary: In many countries, the honey bee is the only bee species used in pesticide risk assessments. However, estimating pesticide risk for bees other than honey bees might reveal different means by which other bee species are exposed to and affected by pesticides, because of differences in bee behavior, where they live, and their unique life cycles. We applied the vulnerability concept in chemical risk assessment to 10 bee species including the honey bee, two bumble bee species, and seven solitary bee species with different nesting strategies. The concept we applied considers both the evaluation of a species as an individual (exposure and effect) and as a population (recovery), and thus the assessment goes beyond how sensitive an individual is to a pesticide compared to an assessment in standard laboratory studies, linking it to effects on populations in the field. Based on judgement offered by bee experts, certain bee characteristics were classified by relationships to the likelihood of pesticide exposure, potential effects and ability of the population to recover. The results suggested that the bumble bees and solitary bees included in our study are potentially more at risk to pesticides than honey bees, particularly with respect to exposure and potential for a bee population to recover from having many individuals negatively affected by the pesticide. Our analysis highlights many areas where we still lack knowledge for understanding the interaction between various bees in their natural environments and how they may be exposed to and harmed by pesticides.

Technical Abstract: In many countries, the Western honey bee is used as surrogate in pesticide risk assessments for bees. However, uncertainty remains in the estimation of pesticide risk to non-Apis bees because their potential routes of exposure to pesticides, life histories, and ecologies differ from honey bees. We applied the vulnerability concept in chemical risk assessment to 10 bee species including the honey bee, two bumble bee species, and seven solitary bee species with different nesting strategies. The trait-based vulnerability considers both the evaluation of a species at the organism (exposure and effect) and the population level (recovery), and goes beyond the sensitivity of individuals to a toxicant assessed in standard toxicity studies in the laboratory, linking it to effects on populations in the field. Based on expert judgement, each trait was classified by its relationship to the vulnerability to pesticide exposure, effects, and population recovery. The results suggested that the non-Apis bees included in our approach are potentially more vulnerable to pesticides than the honey bee, particularly with respect to traits governing exposure risk and population recovery potential. Our analysis highlights many uncertainties related to the interaction between bee ecology and the potential exposures and population-level effects of pesticides.