Two in one: DNA taxonomy of Acronicta major complex (Lepidoptera: Noctuidae) reveals previous misidentifications and faunal connection in East Asia

The Korean populations of Acronicta major (Bremer, 1864) were reexamined with genital morphology and DNA barcodes. They were turned out to be a mixture of the true A. major and another species, Acronicta gigasa Chang, 1991. The alleged aberration of A. major, ab. anaedinella Strand, 1916, is associated with A. gigasa. The distributional range of A. gigasa is expanded to include Korea and southern China. A possible faunistic belt crossing Korea, southern China and Taiwan is discussed with exemplar lepidopterans. The divergence patterns of A. major and A. gigasa in East Asia are hinted by our estimation of their COI genetic distances. Our finding raises an issue of reconsideration in the hitherto-known information on the distribution, host-range and pest status of A. major in Korea.