Potential distribution of Schistocerca gregaria gregaria in southwestern Asia.
The northern subspecies of desert locust Schistocerca gregaria gregaria has recently expanded into western Asia. It poses a serious threat to food security in areas that are already socially and politically unstable. Its further expansion into other parts of southwestern Asia is an issue of great concern (e.g., China). We assembled S. g. gregaria occurrence records that were accumulated by the Food and Agriculture Organization and environmental variables that summarized aspects of climate, soil condition and vegetation. We predicted the potential distribution of S. g. gregaria via the fine-tuned Maxent model and ensemble ecological niche model approaches. The models predicted that India and other southwestern Asian countries face high risk of S. g. gregaria invasion because of the presence of suitable habitats and the absence of natural barriers that would prevent S. g. gregaria dispersal into these areas. By contrast, the risk of S. g. gregaria invasion in China is low because the suitability values were very low. Moreover, the Tianshan Mountains, the Kunlun Mountains and the Himalaya Mountains may act as natural barriers against S. g. gregaria dispersal. Responses of S. g. gregaria to these environmental variables were modelled using fine-tuned Maxent models.