Landmark Data to Distinguish and Identify Morphologically Close Tabanus spp. (Diptera: Tabanidae)

Area of Science:

• Entomology
• Morphometrics
• Biodiversity and Taxonomy

Background:

• Horse flies (Tabanus spp.) are significant vectors of animal pathogens.
• Distinguishing morphologically similar species like Tabanus megalops, Tabanus rubidus, and Tabanus striatus is challenging.
• Traditional morphological and molecular methods struggle to differentiate these closely related Tabanus species.

Purpose of the Study:

• To evaluate the effectiveness of wing geometric morphometrics for distinguishing and identifying three sympatric Tabanus species in Thailand.
• To establish a reliable method for differentiating Tabanus megalops, Tabanus rubidus, and Tabanus striatus.

Main Methods:

• Landmark-based geometric morphometrics applied to digitized images of female horse fly wings.
• Analysis of 22 wing landmarks from Tabanus megalops (n=160), Tabanus rubidus (n=165), and Tabanus striatus (n=85) collected in Thailand.
• Statistical analysis of wing shape variations to assess species discrimination accuracy.

Main Results:

• Wing shape analysis achieved high accuracy in distinguishing between the three Tabanus species, with scores ranging from 94.38% to 99.39%.
• Geometric morphometrics proved effective in differentiating morphologically cryptic species within the Tabanus genus.
• The study provides a reference dataset for tentative identification of new field-collected specimens.

Conclusions:

• Wing venation geometry is a reliable tool for distinguishing closely related Tabanus species.
• Geometric morphometrics offers a robust solution for taxonomic challenges posed by morphologically similar insects.
• This method enhances the ability to accurately identify disease vectors, contributing to disease control efforts.