Mitochondrial Genomes Reveal Population Structure of the Locust Oedaleus decorus (Orthoptera: Acrididae: Oedipodinae) in China

The locust Oedaleus decorus undergoes massive outbreaks and engages in round-trip migratory flights across northern China and Mongolia. However, its specific genetic structure remains poorly understood. In this study, we sequenced the complete mitochondrial genomes of 163 O. decorus individuals from 16 locations in northern China using high-throughput sequencing data and analyzed its population structure. The results showed that these mitochondrial genomes are 15,142 to 15,914 bp in sizes, with size variation attributed to A + T-rich regions in intergenic spacers. All 13 protein-coding genes exhibited conserved lengths across samples. The overall genetic differentiation between populations was small (Fst = 0.00843), with high gene flow (Nm = 29.40). Both genetic differentiation and DAPC analyses revealed significant genetic differentiation in the New Barag Left Banner (NBL) population compared to the Zhengxiangbai Banner (ZB), Taibus Banner (TP), Xianghuang Banner (XH), and Zhenglan Banner (ZL) populations. The phylogenetic tree and haplotype network suggest Hap_20 is presumably a relatively ancestral haplotype and all haplotypes were divided into two clades, and no population formed a distinct independent clade. Our findings indicate that the O. decorus population in North China exhibits mitochondrial subtype differentiation. The lack of difference in genetic structure across different regions in North China is consistent with a high level of migratory activity by O. decorus in the region.