Critical thermal thresholds for survival and feeding in the invasive bark beetle Pagiocerus frontalis reveal mechanisms of stored-maize vulnerability

Stored grains are highly vulnerable to insect pests, which can cause significant post-harvest losses worldwide. The invasive bark beetle Pagiocerus frontalis (Coleoptera: Curculionidae: Scolytinae) poses a major threat to maize and avocado seeds, yet the influence of temperature on its biology and damage potential is poorly understood. Here, we examined the effects of six constant temperatures (13, 17, 21, 25, 29, 33 °C) on survival, development, reproduction, and grain damage. Beetles thrived under moderately warm conditions (21, 25 and 29 °C), with the highest progeny, grain damage, and weight loss at 25 °C, while extreme temperatures (13 or 33 °C) suppressed activity and reproduction. These findings clarify the species’ thermal preferences and suggest that controlling storage temperature, either by cooling or heat treatment, could reduce pest-induced losses, providing a sustainable, non-chemical strategy for protecting stored grains. This information can also be incorporated into climate-based predictive models to forecast pest survival, establishment, and potential damage.