Predicting Habitat Suitability of Nine Major Grassland Insect Pests in Yunnan, China, Under Climate Change Scenarios

Climate change may alter grassland pest distributions, yet province-wide comparisons based on extensive field surveys remain limited in Yunnan, China. We analysed 10,342 census and special-survey records, retaining 4281 species–climate-cell records for nine pests. Five WorldClim predictors entered ten-algorithm ensembles weighted by the true skill statistic (TSS), evaluated using nested spatial cross-validation. Three climate models projected SSP1-2.6, SSP2-4.5, and SSP5-8.5 across four 20-year periods spanning 2021–2100. Predictive performance varied among species: area under the receiver operating characteristic curve (AUC) ranged from 0.591 to 0.778, and TSS from 0.198 to 0.365. Pseudoxya diminuta had the highest AUC (0.778), Patanga japonica the highest TSS (0.365), and the 27-cell Holotrichia parallela model the lowest AUC (0.591). Warm-quarter precipitation ranked first for six species, with mean permutation-induced AUC decreases of 0.054–0.145. Baseline threshold-defined suitable area was largest for Oxya chinensis (235.3 × 103 km2). By 2081–2100 under SSP5-8.5, consensus suitable area declined by 63.4% for P. japonica and 54.6% for P. diminuta. These species-specific climatic associations and projected changes provide a basis for coordinated provincial surveillance, supported by survey-derived county–township revisit priorities.