Parallel evolution of an alpine type ecomorph in a scorpionfly: Independent adaptation to high-altitude environments in multiple mountain locations

Elucidation of the diversification process of organisms is one of the important tasks of biology. From the viewpoint of species diversity, insects are the most successful group among the diverse organisms on earth and evolutionary adaptation is one of the important factors driving this pattern. Evolutionary adaptation is one of the important factors in the diversification of insects. One of the representative examples of environmental adaptation in insects is the shortening and loss of wings in subalpine and alpine zones. In this study, we focused on the Japanese scorpionfly, Panorpodes paradoxus. In this species, individuals that inhabit mountainous regions and subalpine zones have long wings (the general type), and individuals that inhabit higher altitudinal ranges have short wings (the alpine type). We collected samples of all Japanese Panorpodes species and one Korean Panorpodes species, and conducted molecular phylogenetic analyses of the mtDNA COI (610 bp), COII (688 bp), and 16S rRNA (888 bp) and nuDNA EF1-alpha (658 bp) and 28S rRNA (524 bp) regions in order to reveal the evolutionary history of the alpine type of P. paradoxus. As a result of molecular phylogenetic analyses, it was revealed that the alpine type of P. paradoxus was polyphyletic, and had evolved to become the alpine type at least twice independently at separate mountain locations. In addition, the result of divergence time estimation suggested that the alpine type is an ecomorph, having recently adapted to low temperature habitats following mountain uplift within the Japanese Archipelago and subsequent glacial-interglacial cycles.