Evolutionary history and divergence times of Tettigoniidae (Orthoptera) inferred from mitochondrial phylogenomics

Tianyou Zhao ¹ Zhenbin Lin ¹ Hailin Yang ² Fan Song ¹ Zhenyuan Xia ^3* Weidong Huang ^1*

• ¹ Key Laboratory for Monitory and Green Control of Crop Pest, Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China
• ² Yunnan Tobacco Company, Yuxi Branch, Yuxi, China
• ³ Yunnan Academy of Tobacco Agricultural Sciences, Kunming, Yunnan Province, China

Advances in high-throughput sequencing technology have led to a rapidly increasing in the number of sequenced mitochondrial genomes (mitogenomes), ensuring the emergence of mitochondrial phylogenomics, a powerful material for understanding evolutionary history at various animal groups.In this study, we utilized high-throughput sequencing technology to assemble and annotate the mitogenomes of Letana rubescens (Stå l) and Isopsera denticulata Ebner. We have described the mitochondrial genes characteristics of these two species. Selection pressure analysis on the 13 PCGs and two ribosomal RNA genes revealed that only ND1 and COX1 contained positively selected sites, while negative selection dominated across all genes, indicating that mitochondrial genes primarily function to maintain genetic integrity. Additionally, we assessed the evolutionary rates of the 13 PCGs and two ribosomal RNA genes across the five major subfamilies using mean pairwise identity analysis. Using 13 protein-coding genes (PCGs) and two ribosomal RNA (rRNA) genes, we reconstructed the phylogenetic relationships of the Tettigoniidae by combining published and our newly generated data. We used likelihood mapping, signal-to-noise ratio (SNR), and saturation analysis across different datasets to ensure the robustness of our inferred topologies. Our results have provided more precise insights into the relationships within the Tettigoniidae, spanning from the subfamilies to, tribes, genera, and species level. We further estimated divergence times of Tettigoniidae using four fossil calibration nodes in MCMCTree, dating the origin time of katydids at the early Paleogene period (about 60.86 Mya) and identifying the divergence nodes for five major subfamilies.