BeeGUTS—A Toxicokinetic–Toxicodynamic Model for the Interpretation and Integration of Acute and Chronic Honey Bee Tests

Abstract

Understanding the survival of honey bees after pesticide exposure is key for environmental risk assessment. Currently, effects on adult honey bees are assessed by Organisation for Economic Co-operation and Development standardized guidelines, such as the acute and chronic oral exposure and acute contact exposure tests. The three different tests are interpreted individually, without consideration that the same compound is investigated in the same species, which should allow for an integrative assessment. In the present study we developed, calibrated, and validated a toxicokinetic-toxicodynamic model with 17 existing data sets on acute and chronic effects for honey bees. The model is based on the generalized unified threshold model for survival (GUTS), which is able to integrate the different exposure regimes, taking into account the physiology of the honey bee: the BeeGUTS model. The model is able to accurately describe the effects over time for all three exposure routes combined within one consistent framework. The model can also be used as a validity check for toxicity values used in honey bee risk assessment and to conduct effect assessments for real-life exposure scenarios. This new integrative approach, moving from single-point estimates of toxicity and exposure to a holistic link between exposure and effect, will allow for a higher confidence of honey bee toxicity assessment in the future.

Comparing Sensitivity of Different Bee Species to Pesticides: A TKTD modeling approach

“…Chronic test. In a chronic test, the bees are fed contaminated food from the start with a fixed concentration, so the concentration is assumed to be constant over time (Baas et al, 2022).…”

“…The model outline and the settings of the parameters for interpretation of acute tests is given in Section 2 of the Supporting Information, in which the model is applied to the different available studies and the parameters are estimated. The data published by Heard et al (2017) and Baas et al (2022; both studies only for honey bees) are the starting point for comparison of the sensitivities of different species of bees. The available data for the different compounds on honey bees were complemented as far as possible by data on different species of bees generated in our own laboratories and from the literature.…”

“…With the available data, this approach was used to calculate the effect thresholds for all compounds derived from chronic honey bee tests that were published by Baas et al (2022); the results are summarized in Table 8.…”

“…These tests are carried out in a similar way for different species and are based on the acute oral test for honey bees (Organisation for Economic Co‐operation and Development [OECD], 1998a), or the acute contact test for honey bees (OECD, 1998b). A chronic oral test (OECD, 2017a) is also available, but this is not frequently used, and bee sensitivity comparisons based on chronic tests are only reported for a limited number of species and/or compounds (Baas et al, 2022; Heard et al, 2017).…”

“…Prediction of effect thresholds for different species of bees based on available chronic data for the honey bee (μg/bee) Effect thresholds derived from chronic data for honey bees taken fromBaas et al, 2022. …”