Habitat segregation and genetic relationship of two heptageniid mayflies, Epeorus latifolium and Epeorus l-nigrus, in the Shinano-gawa River basin

摘要: The heptageniid mayflies Epeorus latifolium and l-nigrus are often the dominant species in upper midstream areas of Japanese rivers; as such, they play a significant role river ecosystems. However, although these two have been identified using morphological characteristics male its adult stage, it is impossible to differentiate them their nymphal stage. We conducted study elucidate distribution pattern, i.e., current Shinano-gawa River basin, based on quantitative field sampling genetic analysis nymphs also some adults; for these, was possible between reliably. data collected from 30 sites 1-year-long revealed that E. and/or clearly distributed over very broad area, appeared be at about third sites. Based our analysis, including several specimens l-nigrus, respectively form separate monophyletic clades. That is, genetically differentiated, considered each represent discrete species. Then, we plotted collection reliably basin map. This resultant map displays stream area rather than l-nigrus. To conclude, pronounced ‘habitat segregation’ or ‘current distribution’ observable.