DNA barcodes narrow down the possible sources of introductions of an invasive banana skipper, Erionota torus Evans (Lepidoptera, Hesperiidae)

The banana skipper, Erionota torus Evans (Lepidoptera, Hesperiidae, Hesperiinae, Erionotini) is a South-east Asian pest of banana that, in the last 60 years, has spread to the southern Philippines, Taiwan, Japan, India, Sri Lanka, Mauritius and La Réunion, and potentially threatens Africa and Tropical America. A partial library of DNA barcodes from the indigenous and introduced ranges was built. Based on our analysis, the indigenous populations can be divided into an ‘East’ group, in China and Vietnam, and a ‘West’ group in India, Nepal, Myanmar and west Malaysia. Further, within the ‘West’ group, there is a coherent ‘Malaysia’ subgroup from west Malaysia. Introduced populations in south India, La Réunion and Taiwan showed almost no variation in barcodes, suggesting they are each based on a single homogenous introduction. We conclude that the introduced populations in Taiwan and Japan match the ‘East’ group, the introduced populations in Mauritius and La Réunion match the ‘Malaysia’ subgroup and the introduced population in south India matches the ‘West’ group. These results are discussed in the context of existing ideas regarding the source of each introduction, and the implications in terms of pathways of entry.