Assessing Biodiversity in Madagascar with Leech-Derived iDNA: Methodological Advancements and Ecological Insights

Mai Ahmed Ezzeldin Fahmy, Fordham University


Global biodiversity is currently declining at unprecedented rates due to anthropogenic activities and interventions are needed to preserve remaining diversity. Baseline measures of biodiversity are needed against which to test the efficacy of such interventions in conserving species over time. Biodiversity inventories are used to establish these baselines, often relying on tools such as camera traps and Sherman traps, among others. With the advent of next generation sequencing, targeting residual species DNA from environmental sources (eDNA) has emerged as an efficient means of taking inventory of biodiversity. Of these environmental sources, blood feeding invertebrates have also been tested in their ability to preserve host DNA (invertebrate-derived DNA, iDNA). The aim of this dissertation is to test and optimize the use of terrestrial blood feeding leeches of the family Haemadipsidae in sampling vertebrate biodiversity. I have developed a methodology for collecting leeches (Chtonobdella spp.), sequencing host DNA, and assigning taxonomic identity and I have implemented it in the forests of Madagascar, sampling some of the world’s most endangered biodiversity. I have shown that increasing barcoding loci increases taxonomic identifications, and that pooling individual bloodmeal DNA isolates for next generation sequencing is more efficient than individually targeting bloodmeals with traditional Sanger sequencing and fewer loci. I show that iDNA complements conventional biodiversity surveying methods, detecting distinct vertebrate fauna. This dissertation also presents evidence for a new species of terrestrial leech (Chtonobdella mangevoensis sp. n.), and I describe its morphology with micro-computed tomography (μCT) imaging. I have helped establish terrestrial leeches as valuable tools for biodiversity monitoring and I have improved our understanding of their behavior as understudied organisms.

Subject Area

Conservation biology|Bioinformatics|Molecular biology

Recommended Citation

Fahmy, Mai Ahmed Ezzeldin, "Assessing Biodiversity in Madagascar with Leech-Derived iDNA: Methodological Advancements and Ecological Insights" (2023). ETD Collection for Fordham University. AAI30246582.