Date of Award

2-23-2026

Thesis Type

PhD

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Divisions

Institute for Advanced Studies

Institution

Universiti Malaya

Abstract

Black flies (Diptera: Simuliidae) are ecologically significant insects with complex interactions in freshwater and terrestrial ecosystems. In Malaysia, despite extensive research on their aquatic stages, knowledge of adult black fly ecology, distribution and microbial communities remains limited. This study addresses these gaps through three interconnected studies. The first objective investigated the ecological characteristics of wild-caught adult black flies in Peninsular Malaysia. Using Malaise traps across 41 ecological landscapes, 532 adult black flies, representing 14 species, were collected. The study found that lower elevation habitats harboured higher species richness, with Simulium roslihashimi being the most frequently captured species. Environmental factors such as elevation, temperature and humidity were found to influence species distribution. The second objective updated the DNA barcode reference database for Malaysian black flies. A total of 59 new sequences from 22 species were added to GenBank and GBIF databases, with 14 species barcoded for the first time. The study revealed a DNA barcode gap in 80% of species, while cryptic diversity was suggested in groups such as Simulium auratum and Simulium pegalanense. The subgenus Nevermannia showed the highest rate of correct species identification, while Gomphostilbia presented mixed results due to genetic similarity among closely related species. The third objective examined the microbial communities of Simulium vanluni across different body parts. This species was chosen after it was wildly caught with the most number of individuals, thus allow many replicates to ensure a consistent and reliable result. Using 16S rRNA gene sequencing, the findings demonstrated distinct bacterial communities in the head, thorax and abdomen of the S. vanluni. Overall, the bacterial communities were predominantly composed of Proteobacteria, with Wolbachia, Rickettsia and Acinetobacter being the most abundant genera in all body parts. The thorax and abdomen showed higher bacterial diversity compared to the head, suggesting these regions offer more microhabitat and functions especially in term of symbiosis interaction. Finally, this study provides valuable insights into the ecology, molecular taxonomy and microbiome of Malaysian black flies. The findings contribute to public health strategies for vector-borne disease surveillance and offer a foundation for future research on black fly biology and ecology in the region.

Initial

khm

Additional Information

Thesis (PhD) – Institute for Advanced Studies, Universiti Malaya, 2026.

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