Phylogenetics and Evolutionary Dynamics of Yunnan Acrididae Grasshoppers Inferred from 17 New Mitochondrial Genomes

Simple Summary: Yunnan Province in southwestern China is home to a rich variety of grasshoppers, particularly from the Acrididae family, which play key roles in ecosystems and agriculture. However, understanding the phylogenetic relationships and evolution of these grasshoppers has been difficult using just their physical traits. To gain deeper insights, our study analyzed the mitochondrial DNA-the genetic material passed from mothers to offspring-of 17 different Acrididae species found in Yunnan. By comparing these new genetic sequences with those from 46 other Acrididae species, we were able to construct a detailed family tree showing how these grasshoppers are related. Our findings revealed that some groups previously thought to be closely related are not, suggesting that the existing classification needs to be updated. Additionally, we determined that the diversification of these grasshoppers occurred alongside significant geological and climate changes in the region over 50 million years ago. This research not only clarifies the evolutionary history of Yunnan's grasshoppers but also provides essential information for conserving their diverse populations. By improving our understanding of these insects, we can probe into their accurate phylogeny. Yunnan Province, a global biodiversity hotspot, hosts a diverse array of Acrididae grasshoppers essential for ecosystem dynamics and agriculture. To elucidate the phylogenetic relationships and evolutionary history of this group, we sequenced and analyzed complete mitochondrial genomes from 17 Acrididae species endemic to Yunnan, with genome lengths ranging from 15,403 to 15,943 base pairs. These data were integrated with mitochondrial sequences from 46 additional species to construct comprehensive phylogenetic trees. The maximum-likelihood tree identified four major clades with robust support (bootstrap values > 90%), revealing significant lineage diversification during the Early Eocene (51.94 million years ago, Mya) and subsequent radiations in the Miocene (similar to 20 Mya) and Pliocene (similar to 5 Mya). These divergence times correlate with major geological events and climatic shifts in the region, such as the uplift of the Tibetan Plateau and the intensification of the Asian monsoon. Notably, several species within the Coptacrinae and Oxyinae subfamilies, particularly Pseudodotraulia cornuata and Spathosternum prasiniferum, were found to be polyphyletic, indicating the necessity for taxonomic revisions. Further cluster analyses of codon usage bias and genetic distance support these taxonomic revisions within Acrididae. This robust phylogenetic framework underpins conservation strategies aimed at preserving Yunnan's rich grasshopper biodiversity and informs updates to their phylogeny.