Black flies (Simuliidae) are one of the world's most medically significant groups of the blood-sucking insects. Females of certain species cause skin conditions like itching, rash and edema in humans and other animals and also serve as vectors of both human and zoonotic forms of river blindness, or onchocerciasis. At the same time, black flies are also an ideal freshwater bioindicator because immature stages can breed only in clean running rivers and streams.
Led by the world-renowned black fly taxonomist, Prof. Emeritus Dr. Hiroyuki Takaoka, the project team has carried out field surveys of black flies in seven Southeast Asian countries since 2010. The expeditions have discovered 145 new species from five subgenera of the genus Simulium (30 from Malaysia, 48 from Vietnam, 17 from Thailand, ten from Indonesia, three from Myanmar, two from the Philippines and one from Laos), bringing the total number of described Asian species in the family to 599.
Despite these advances in knowledge of Simuliidae diversity in Southeast Asia, the idenfification of black flies is challenging. The family is well-known as the most structurally uniform taxa, and the differences between species typically rely on subtle characteristics in one or two life stages. As such, research into black flies can benefit greatly from a DNA barcode library to facilitate rapid and accurate identification of known species while accelerating the pace of discovery by highlighting those morphologically similar but genetically distinct taxa (cryptic species) that may represent new species.
This project will digitize black flies from Southeast Asia and seek to address taxonomic issues via DNA barcoding and metabarcoding approaches, providing a way forward for establishing a DNA barcode library for the family Simuliidae and long-term improvements and additions to black fly information in Southeast Asia.
At midterm reporting the project published a dataset containing a total of 284 occurrence data of black flies (Diptera: Simuliidae) in Malaysia, Indonesia and Viet Nam.
The reported data was aided by morphological and DNA barcoding COI analyses, of which 21 species in Malaysia, 30 species in Indonesia, and 47 species in Viet Nam were successfully sequenced.