Speciation of the cold-adapted scorpionfly Cerapanorpa brevicornis (Mecoptera: Panorpidae) via interglacial refugia

Pleistocene climate changes played a significant role in the speciation of temperate insects. Cold-adapted species responding to past climatic events, however, remain rarely investigated in most groups of insects. We assessed the evolutionary history and speciation of the cold-adapted scorpionfly Cerapanorpa brevicornis (Hua and Li), endemic to the Qinling-Bashan Mountains and adjacent regions (QBMARs), based on one nuclear and three mitochondrial DNA gene markers. Two distinctly divergent lineages were found in C. brevicornis dating back to 0.56 Ma, approximately coinciding with the extra-long interglaciation (0.48-0.62 Ma) during the middle Pleistocene. Lineage I is widely distributed in the QBMARs, and Lineage II is confined to the 'sky islands' of the eastern Bashan Mountains (EBMs). The patch of 'alpine archipelagos' in the EBMs seems to function as interglacial microrefugia. In contrast, interglacial macrorefugia are located in the Qinling Mountains. These findings may highlight the essential role of postglacial warming in the speciation and generation of neo-endemic species through range contraction in cold-adapted species and may provide new insights into the mechanisms underlying the high endemism and species richness in the QBMARs. This study suggests that Lineage II can be treated as a good species acting as an indicator of climate change, and the 'sky islands' of the EBMs might be a high-priority region for alpine biodiversity conservation under global warming.

Automated summary

Pleistocene climate changes have significantly influenced the speciation of temperate insects, with cold-adapted species like Cerapanorpa brevicornis showing two divergent lineages dating back to approximately 0.56 Ma. Lineage II of this species could serve as an indicator for climate change, and conservation efforts in the 'sky islands' of the eastern Bashan Mountains may be crucial under global warming.