How relevant are temperature corrections of toxicity parameters in population models for environmental risk assessment of chemicals?

Population models provide insights into population dynamics under diverse and untested chemical exposure scenarios, supporting their environmental risk assessment (ERA). In this study, we investigate the interplay of temperature and imidacloprid exposure on population dynamics using an Individual-Based Model (IBM) incorporating a dynamic energy budget (DEB) model for population dynamics and toxicokinetic-toxicodynamic models of the General Unified Threshold model for Survival (GUTS) framework to predict toxicity effects. For this, we tested different model configurations, where i) only the DEB parameters are corrected for temperature, as is common practice, and ii) also the TKTD parameters of the GUTS model are corrected for temperature. In doing so, we aim to evaluate the importance of temperature corrections in the GUTS model within an IBM framework. As expected, increased temperature amplitudes increase the range of simulated population sizes, and chemical exposure reduces the maximum population size. The combined effect of correcting both the DEB and TKTD parameters, however, yield an overall strongly negative effect on population sizes, particularly at lower temperatures. These results highlight the necessity of temperature-sensitive parameterization in population models for a protective risk assessment under the projected future climate conditions with increased temperatures and variability. Future considerations include incorporating local adaptations and acclimatization, particularly in different climate zones, to accurately interpret population model outcomes in the context of evolving environmental conditions. Such insights contribute to the refinement of ecological realism in ERA, enhancing the robustness of chemical risk management strategies.