Gene Flow and Diversification in Species Complex (Trichoptera: Rhyacophilidae) in the Hengduan Mountains.

The Hengduan Mountains are one of the most species-rich mountainous areas in the world. The origin and evolution of such a remarkable biodiversity are likely to be associated with geological or climatic dynamics, as well as taxon-specific biotic processes (e.g., hybridization, polyploidization, etc.). Here, we investigate the mechanisms fostering the diversification of the endemic complex, a poorly known group of aquatic insects. We used multiple allelic datasets generated from 691 AHE loci to reconstruct species and RaxML phylogenetic trees. We selected the most reliable phylogenetic tree to perform network and gene flow analyses. The phylogenetic reconstructions and network analysis identified three clades, including , sensu stricto and cf. . sensu stricto and cf. present an intermediate morphology between and the closest known relative to the -complex. The gene flow analysis revealed extensive gene flow among these lineages. Our results suggest that and are likely to have contributed to the evolution of sensu stricto and cf. via gene flow, and thus, our study provides insights in the diversification process of a lesser-known ecological group, and hints at the potential role of gene flow in the emergence of biological novelty in the Hengduan Mountains.