Spatial prediction of Spodoptera frugiperda expansion in India using MaxEnt under shifting climate regimes

The Fall Armyworm (FAW), Spodoptera frugiperda, is a highly invasive pest threatening graminaceous crops and global food security due to its aggressive feeding and migratory behavior. Abiotic factors, particularly climatic variables, along with the spatial distribution of maize, its primary host, play a critical role in shaping the geographic distribution, survival, and development of S. frugiperda. As a recent invader in India, understanding its potential spread under changing climate conditions is essential. This study applied the MaxEnt model using CMIP6 climate projections (BCC-CSM2-MR and MIROC6) under SSP126 and SSP585 scenarios to forecast FAW distribution. The model showed strong predictive accuracy (AUC > 0.85; TSS = 0.59), with annual temperature range (Bio7) and maize distribution identified as key predictors. Under current conditions, 40.5% of India is suitable for FAW, with high suitability concentrated in southern and eastern states. Projections for 2030 suggest slight expansion under SSP126 (41%) and contraction under SSP585 (37%) in the BCC-CSM2-MR model, while MIROC6 estimates 39% and 40%, respectively. Interestingly, suitability is projected to increase in central and northeastern regions, while optimal zones may shrink due to thermal stress. These findings highlight FAW's expanding risk under climate change and provide actionable insights for climate-resilient pest management in India.