A global comparison of DNA sequences of Pelopidas (Lepidoptera: Hesperiidae) reveals discordance between morphological and genetic data, and an insular ‘ghost’ population

The Pelopidas are a widely distributed genus of hesperiids ranging from the Afrotropical to Australasia. Based on traditional classification, four species are recorded from Sri Lanka: Pelopidas agna, P. mathias, P. subochracea and P. conjuncta.
The aim is to test the taxonomic hypotheses of the Sri Lankan Pelopidas as they are currently recognised based on morphology. We achieve this by analysing the phylogenetic relationships among the Pelopidas as well as between the Pelopidas and tribe Baorini both inside and outside of Sri Lanka.
We used DNA sequence data from the cytochrome oxidase c subunit I (COI) “barcode” region and two nuclear DNA regions, elongation factor 1‐α (EF1‐α) and wingless (Wgl) collected for Sri Lankan Pelopidas and combined with all available Pelopidas sequence data from public databases.
The reconstructed phylogeny showed that P. mathias, P. agna and P. conjuncta were not monophyletic. Additionally, P. agna in Sri Lanka may now be a hybrid population that retains the P. agna morphology but possesses the mitochondrial DNA of P. mathias (termed a ‘ghost’ population). Finally, two lineages of P. conjuncta were identified in Sri Lanka, appearing more closely related to other species of Pelopidas than to each other.
This study demonstrates the phylogenetic complexity within the Pelopidas and the uniqueness of the Sri Lankan Pelopidas that have not been previously appreciated. This new knowledge is important in planning conservation management and may also guide future work on the potential mechanisms of evolutionary diversification of island butterflies.