Application of Invertebrate-Derived DNA Barcoding (iDNA) in Blood Sucking Leeches From West Sumatra: A Discovery of Blue-Eyed Litter Frog Leptobrachium waysapuntiense

Abstract

Indonesia is one of the world's most biodiversity-rich countries, including a wide variety of vertebrate and plant species. However, assessing biodiversity in tropical rainforests remains challenging itself. The use of conventional tools has commonly been employed for monitoring and research purposes. Invertebrate-derived DNA (iDNA), a subdiscipline of environmental DNA (eDNA), has emerged as a noninvasive tool that complements traditional methods for biodiversity assessment. It enables the detection of vertebrate species and the monitoring of their populations through molecular approaches. Utilizing abundant haematophagous leeches provides a promising approach to sample a broader range of host species within an area, as these leeches retain high-quality host DNA in their guts for extended periods. Using Sanger sequencing with five primer sets (16Scp, 16Sed, 12S, ND2, and RepCOI) designed to target broad taxonomic groups, 272 Haemadipsa spp. samples were successfully amplified, resulting in the identification of 17 unique vertebrate hosts, including mammals, amphibians, and reptiles. Within our 16Sed results, we noted that the primer sets could capture a broader range of taxa than originally targeted, encompassing both mammals and reptiles, thereby enhancing species richness detection. Notably, we present evidence of the first iDNA-based detection of the rare blue-eyed litter frog, Leptobrachium waysepuntiense, from western Sumatra. Therefore, this study suggests that the use of haematophagous leeches represents a promising approach for biodiversity monitoring in Indonesia. This method offers a complementary strategy that can be integrated with existing practices to strengthen conservation efforts.