Insights into the Divergence of Chinese Bark Beetles during Evolutionary Adaptation.

Many bark beetles of the genus are economically important insect pests that cause severe damage to conifer forests worldwide. In this study, sequencing the mitochondrial genome and restriction site-associated DNA of bark beetles helps us understand their phylogenetic relationships, biogeographic history, and evolution of ecological traits (e.g., pheromones and host plants). Our results show that the same topology in phylogenetic trees constructed in different ways (ML/MP/BI) and with different data (mtDNA/SNP) helps us to clarify the phylogenetic relationships between Chinese bark beetle populations and Euramerican species and their higher order clades; bark beetles are polyphyletic. The structure of the mitochondrial genome of bark beetles is similar and conserved to some extent, especially in the sibling species and . Genetic differences among species are mainly related to their geographic distribution and different hosts. The evolutionary pattern of aggregation pheromones of species reflects their adaptations to the environment and differences among hosts in their evolutionary process. The evolution of species is closely related to the uplift of the Qinghai-Tibet Plateau and host switching. Our study addresses the evolutionary trend and phylogenetic relationships of bark beetles in China, and also provides a new perspective on the evolution of bark beetles and their relationships with host plants and pheromones.