Wing geometric morphometry of tabanid flies in Thailand

Tabanid flies are gaining high medical and veterinary importance due to
their role as a vector of many pathogens. In the present study, a total of
3760 female tabanid flies were collected from Narathiwat and Phayao
provinces of Thailand. All were identified using the morphological method,
DNA barcoding, and wing geometric morphometric (WGM) analysis. Eight
species were identified, and among them, Tabanus tenens is a new recorded
Thai horse fly. Morphologically, 2178 and 1559 females from Narathiwat and
Phayao were identified at the species level, including Chrysops dispar,
Chrysops fasciatus, Tabanus griseilineis, Tabanus rufiscutellatus, and
Tabanus minimus. The other 23 females were identified at the level of the
genus (Tabanus spp.) only. Among these, DNA barcoding was further
identified as Tabanus tenens, Tabanus rubidus, and Tabanus striatus. The
landmark-based WGM analysis was used to differentiate the samples from
Narathiwat, and the results showed the efficacy of this approach in
differentiating the four species of tabanids, achieving an overall
accuracy score of 99%. Additionally, the data derived from wing landmarks
of samples collected in Narathiwat were used as reference materials for
identification of the tabanid fly collected from Phayao, and the finding
revealed efficacy of the reference materials. Together, this study
demonstrated that DNA barcoding is a reliable tool for the identification
of tabanid fly species, while WGM analysis could be a complementary tool.
The barcode sequences and WGM data generated in this study can serve as a
valuable reference material to identify new field samples from other
regions of Thailand. Altogether, this study updated the species list of
tabanid flies in Thailand, particularly in the Narathiwat and Phayao
provinces, using various integrative identification tools.