Solitary bees, including both wild and managed populations, are important pollinators of crops and wild flower communites. Solitary bees can potentially be exposed to pesticides via multiple routes of exposure which may differ between species and between solitary bees and the Western honey bee (Apis mellifera) which is currently used as surrogate for risk assessments across bee species. Species-specific traits may additionally interact with the potential for exposures and effects, including, for instance, phenology, reproductive rates and flower preferences. We are presenting a population model for solitary bees in agricultural landscapes, SolBeePop. The model was developed to simulate a variety of species by using species-specific ecological traits as model parameterizations. Model parameterizations for several species (Osmia bicornis, O. cornifrons, O. cornuta, O. lignaria, Megachile rotundata, Nomia melanderi, and Eucera (Peponapis) pruinosa) were compiled from the literature whereby data availability varied by species. The model can simulate the diverse life cycles of the species and can be used to explore the importance of uncertainties in data to the population dynamics. Exposures to a pesticide through multiple exposure routes can be considered, such as nectar, pollen, and nesting materials. Effects are implemented using a simplified toxicokinetic-toxicodynamic model, BeeGUTS, adapted specifically for adult bees while an exposure-response functions is applied to simulate effects to developing in-nest life stages. We calibrated and validated the model with control data from semi-field studies conducted with O. bicornis. We applied the model across the model species to assess the impacts of different trait combinations on population dynamics, exposures and population-level effects in relevant landscape scenarios. The model provides a valuable tool for higher-tier pesticide risk assessments across species of solitary bees in agricultural landscapes.

SETAC North America 2022.

Schmolke, A., (Waterborne), Galic N.,  (Syngenta Crop Protection LLC), Roeben, V., Preuss T. G., Miles, M. (Bayer Crop Science), Hinarejos, S. (Sumitomo Chemical). SolBeePop: Assessing Risks of Pesticide Exposures to Population of Solitary Bees in Agricultural Landscapes, a Modeling Approach.