Phylogeography of the Grassland Skipper Ochlodes venatus Supports the Hypothesis That This Japanese Grassland Insect Has a Long History

ABSTRACT

In Japan, with its warm and humid climate, the conservation value of grassland ecosystems has often been underestimated, as they were believed to mainly have been maintained by human activities. It is thus essential to understand when grassland organisms first colonized Japan and have maintained since then to understand the history of grassland ecosystems in Japan. Here, we conducted a phylogeographical study using genome‐wide single nucleotide polymorphisms from MIG‐seq and mitochondrial DNA of Ochlodes venatus (Lepidoptera: Hesperiidae), a grassland skipper species, in Japan and eastern Russia. Genetic analyses showed that the O. venatus groups in northern and western Japan diverged 1.5 million years ago and then hybridized approximately 100,000 years ago. It was also found that O. venatus populations have been maintained in Japan for at least 200,000 years. The long‐term demographic history inferred within Japan is notably longer than that of other grassland insects as estimated in previous studies. The results demonstrated that this grassland butterfly has been present long before human colonization in Japan, and that the Japanese grasslands have been naturally maintained over a long period, highlighting the conservation value of O. venatus in Japan.