Assessment of the Vulnerability to Pesticide Exposures Across Bee Species

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 pesticide 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 the evaluation of a species both at the level of the organism (exposure and effect) and the population (recovery) that goes beyond the sensitivity of individuals to a toxicant assessed in standard laboratory toxicity studies by including effects on populations in the field. Based on expert judgement, each trait was classified by its relationship to the vulnerability to pesticide exposure, effects (intrinsic sensitivity), 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 due to traits governing exposure 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, emphasizing the need for more research to identify suitable surrogate species for higher-tier bee risk assessments. This article is protected by copyright. All rights reserved.