Hybridisation in Colias butterflies (Lepidoptera, Pieridae): identification of natural hybrids using unlinked molecular markers

In this report, we analyze a wild-caught Colias specimen from Kyrgyzstan with unusual wing pattern, which was provisionally identified as a natural hybrid between Colias christophi helialaica Schulte, 1988 and Colias cocandica cocandica Erschoff, 1874 due to its intermediate phenotype. Using one mitochondrial (COI barcode) and three nuclear (Ca-ATPase, H3 and CAD gene fragments) markers, we confirm its hybrid origin and demonstrate that this specimen is a hybrid between a female of Colias christophi helialaica and a male of Colias cocandica cocandica. Our study shows that an analysis of mitochondrial and nuclear molecular markers can successfully discriminate natural hybrids in such a taxonomically challenging group of butterflies as the genus Colias.