When thermal risk indices work and when they don't: A case study of two maize insect pests.

The biological life cycle of terrestrial arthropods, using temperature as the primary driving factor has a large interest for insect pests in agriculture, forestry, urban ecosystems, as constitutes the basics for the development of mathematical models for decision making. A recent study proposed a physiologically-based risk index () which finds large applications in the definition of risk maps; however, further case studies are needed to better explore its strengths and limitations. This study aims to extend this knowledge by presenting an application of the on two economically significant pests: the fall armyworm and the stem borer , major treats for maize production.•While the case of follows the theoretical expectations, providing values for temperature ranges typical of the regions of its confirmed persistence, the model fails for , as for weather conditions where field presence and damage are well-documented.•Accordingly, we trace the breakdown to limiting model assumptions, particularly temperature-only drivers, linear cause-and-effect biodemographic parameters, omission of seasonal dynamics, and reliance on laboratory parameters.•This dual-case contrast highlights both the potential and limitations of and calls for refinements that include a broader ecological realism and data availability.