Predicting Phloeosinus cupressi (Coleoptera: Curculionidae: Phloeosinus) Distribution for Management Planning Under Climate Change

<i>Phloeosinus cupressi</i> Hopkins is an invasive bark beetle that poses a serious threat to <i>Cupressus</i> trees, with potential ecological and economic impacts globally. Native to North America, it has spread to Australia and New Zealand, and climate change may further alter its range. Global trade increases the risk of spread, highlighting the need for predictive modeling in management. In this study, we employed CLIMEX and random forest (RF) models to project the potential global distribution of <i>P. cupressi</i>, incorporating host distribution data for <i>Cupressus.</i> Climatic suitability is concentrated in temperate, subtropical, and Mediterranean zones, including Europe, the U.S., South America, China, Australia, and New Zealand, totaling 10,165.22 × 10⁴ km². Coldest-quarter precipitation (bio19) and annual temperature range (bio7) were identified as the most influential variables. Under RCP6.0 scenarios, suitable areas are projected to expand northward, increasing by ~18%. Regional shifts include contraction in southern Europe and South China, expansion in southern Argentina, southeastern Australia, and coastal New Zealand. Temperature sensitivity is expected to exceed precipitation, enhancing colonization. Due to global <i>Cupressus</i> trade, quarantine and monitoring should focus on high-risk regions. Our findings support early detection, long-term monitoring, and control measures for managing <i>P. cupressi</i> under climate change.