Genetic Diversity of Hemerodromia (Diptera: Empididae) in Thailand

Abstract

Species of Hemerodromia Meigen, 1822 (Diptera, Empididae) are important components of lotic habitats in freshwater ecosystems. The goal of this study was to examine genetic diversity and to test the efficiency of the mitochondrial cytochrome c oxidase subunit I (COI) barcoding region for species level identification of Hemerodromia in Thailand. Twelve Hemerodromia species were collected from 31 sites in North and North Eastern Thailand and 135 COI sequences obtained. Twenty eight sequences from the NCBI database were also included in the analysis. DNA barcoding identification analysis based on the best close match method performed well; with 100% of specimens agreeing with morphological identification. A phylogenetic tree based on the mitochondrial barcode sequences revealed a well-supported monophyly for all Hemerodromia species. Population genetic structure analyses of two geographically widespread species, H. fusca and H. yunnanensis revealed high level of genetic differentiation between populations. This result suggest limitation of gene flow that could be effected by patchy distribution of the forest habitat of these species.

Demographic history of H. fusca and H. yunnanensis revealed that both had undergone population demographic expansion. Lacking the information of the generation time preclude dating of expansion time but it is likely that the demographic expansion in both Hemerodromia species could be related to the Pleistocene climatic and environmental change like those of many other aquatic insects in Thailand.

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