Genetic variation of sand flies (Diptera: Psychodidae) in Gampaha and Kurunegala districts of Sri Lanka: Complementing the morphological identification

Objective: To identity the variation of sand flies in the Gampaha and Kurunegala districts of Sri Lanka and to assess DNA barcoding as a complementing method for morphological identification. Methods: A total of 38 441 sand flies were collected from selected localities in Gampaha and Kurunegala districts using standard entomological techniques from May 2017 to December 2018. Specimens were identified using morphological features and compared with mitochondrial cytochrome C oxidase subunit I gene- based DNA barcoding as an alternative tool. Results: Morphological and molecular identification confirmed the presence of four species under two genera (Phlebotomus and Sergentomyia). Phlebotomus argentipes was the predominant species, followed by Sergentomyia (S.) punjabensis, S. babu insularis, and an unidentified Sergentomyia sp. Phlebotomus argentipes showed a clear genetic differentiation from other species. S. babu insularis and S. punjabensis showed a higher genetic affinity to each other than the unidentified species. The unidentified Sergentomyia species is morphologically similar to S. zeylanica, but differs only in clavate gonostyle. Conclusions: DNA barcoding is an effective technique for the identification of sand flies. Further studies using molecular techniques will improve the knowledge of the cryptic diversity of Sri Lankan sand fly fauna. Establishing a reliable and standardized identification system for sand fly species in Sri Lanka is recommended.