Distribution and sample location of the migratory locusts in China. 'Crosses (+)' in the background represent observed distribution sites of the migratory locusts. Color circles indicate localities of samples studied in this paper: Blue for samples from the Mengxin region, green for East China, red for South China, and orange for Tibetan region. hN* refers to the four samples from Hainan (hNLD, hNSYms, hNSY1 and hNSY2). Dashed line in the map schematically indicates the traditional view of the geographic boundary of the three subspecies in China. Please refer to Table 1 for the geographic origins of locust samples.