Unexpected monophyletic origin of Ephoron shigae unisexual reproduction strains and their rapid expansion across Japan

Abstract

The burrowing polymitarcyid mayflyEphoron shigaeis distri-buted across Japan, Korea, northeast China and far east Russia. Some populations are bisexual, and others are unisexual, i.e. geographically parthenogenetic throughout Japan. In general, parthenogenetic organisms are often found in harsh environments, such as at high latitudes and altitudes, in xeric as opposed to mesic conditions, in isolated habitats such as islands and island-like areas, and at the peripheral regions of the taxon’s range.