Thermal Limits and Future Climate Projections Indicate Declining Habitat Suitability for Mealybug Species of Citrus in Africa

ABSTRACT Global climate change is projected to shift the distributions of a wide range of insect taxa. In agricultural systems, this may influence their pest status and farmers' management efforts. Mealybug species are pests of economic importance on a wide range of agricultural and horticultural crops. However, the potential distribution range of mealybug species attacking citrus remains poorly understood. Using an ensemble species distribution modelling (SDM) approach, we assessed the current and future potential African distribution of Delottococcus aberiae , Nipaecoccus viridis , Planococcus citri , Pseudococcus calceolariae and Pseudococcus longispinus (Hemiptera: Pseudococcidae), all recorded pests of citrus, based on occurrence records and environmental variables. Further, we used thermal tolerance data (CT max ) to map the estimated warming tolerance (WT) for each species under climate change. The mean CT max ranged from 47.3°C ± 0.64°C to 49.6°C ± 0.63°C across species. Delottococcus aberiae showed the highest heat tolerance, whereas P. citri recorded the lowest. From the current climate scenario to projections for the year 2100, WTs decreased across all species. Habitat suitability was spatially heterogeneous under both current and future climate scenarios. However, all five species exhibited substantial contractions in climatically suitable areas by 2100, with projected reductions ranging from approximately 50%–78%. The greatest proportional decline was recorded for P. calceolariae , whereas N. viridis showed the least reduction. These findings indicate widespread future loss of suitable habitat and a high concentration of major citrus‐associated mealybugs within the suitable refugia under climate change. The results are useful for informing monitoring strategies and adaptive pest management planning under current and future climatic conditions.