This study examines the phylogenetic relationships of Simulium tani and Simulium sp. from Vietnam using mitochondrial DNA sequences. Specimens were collected from streams in Vietnam as well as from previous studies in Taiwan, Malaysia, and Thailand. DNA was extracted and sequenced to construct phylogenetic trees. The trees showed that the two Vietnam taxa clustered together but distinct from other locations, indicating low genetic differentiation despite morphological differences. This study provides insights into the species classification and relationships within the Simulium tani species complex.

1. Anukhcha Wannaket A/L Peetak (SEE110004); Supervisor: Prof. Dr. Hiroyuki Takaoka;
Co-supervisor: Dr. Low Van Lun
Division of Ecology and Biodiversity, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Email: bank521@siswa.um.edu.my
Simulium tuberosum species-group is generally found in Palearctic,
Nearctic, and Oriental Regions, and at least 27 morphologically similar
nominal species exist in the Oriental Region (Adler & Crosskey, 2014).
Certain taxa of the family Simuliidae are morphologically inseparable, but
biologically distinct. In this study, the phylogenetic relationships of Simulium
tani species-complex from Vietnam, Taiwan, Malaysia, and Thailand were
inferred from mitochondrial cytochrome c oxidase subunit I (COI) and II
(COII) DNA sequences.
This study examines the phylogenetic relationships of Simulium tani and Simulium sp. of S. tani species-complex of Vietnam. Simulium sp. is
morphologically different from S. tani and similar to S. suzukii from Taiwan and Japan by the pupal gill arrangement. Ten specimens of S. tani collected from
Stream 1, Lam Dong, Vietnam; 12 specimens of Simulium sp. from Stream 9, Lam Dong, Vietnam, 10 specimens of S. suzukii from Taiwan, were used for
DNA analysis using mitochondria encoded cytochrome c oxidase subunit I (COI) and II (COII). Isolates of S. tani species-complex from Malaysia and
Thailand available from the NCBI GenBank database were included for analysis. A maximum parsimony phylogenetic tree for both COI and COII genes
revealed that both S. tani and Simulium sp. from Vietnam are placed in the same cluster, which is distinct in lineage from those of S. tani species-complex
from Taiwan, Malaysia and Thailand.
Figures 8 and 9. Results of maximum parsimony trees indicate distinct
species of Simulium tuberosum species-group from various geographical
areas. Bootstrap values with only more than 50% are shown in the tree.
Abstract
Introduction Results
*Specimens collection from:
• Streams 1 and 9, Lac Duong District, Lam Dong Province, Vietnam,
• Daping River, Beipu Township, Taiwan, and
• Malaysia and Thailand (Sequences available from NCBI GenBank)
DNA extraction, amplification, purification, and sequencing used here,
follow those of Low et al. (2014).
Materials and Methods
To clarify the species status of two taxa (S. tani species-complex &
Simulium sp. of S. tuberosum species-group) collected from Vietnam, and
to infer their phylogenetic relationships with isolates of S. tani species-
complex from Thailand and Malaysia and with S. suzukii from Taiwan.
Objective
I would like to express my deepest appreciation to my supervisor, Prof. Dr.
Hiroyuki Takaoka and my co-supervisor, Dr. Low Van Lun who have guided
me in all aspects of this study. I also thanks to Ms. Vinnie Siow Wei Yin and
Ms. Zubaidah Ya’cob for guidance and support.
Acknowledgement
• It is indicated that two taxa from Vietnam are not separable genetically,
although they are morphologically distinguishable from each other.
• The result obtained is unexpected and represents a striking example
rarely occurring in the family Simuliidae. This may have been caused by
low genetic differentiation between the taxon of S. tani species-complex
and Simulium sp, or the weak sensitivity of the genes used.
• The phylogenetic trees show the relationship of the two taxa from
Vietnam is closer to isolates of S. tani species-complex from Thailand
and Malaysia then to S. suzukii from Taiwan, as expected from the
geographical point of view.
• Further studies on other isolates of S. tani species-complex from various
localities in Vietnam are needed to clarify the species status, and to infer
their phylogenetic relationships with other isolates of S. tani and other
related species of the S. tuberosum species-group.
Discussions
All specimens from Vietnam, Taiwan, Malaysia, and Thailand
populations are placed in different clusters of both phylogenetic trees.
Both S. tani and Simulium sp. from Vietnam are genetically not
separable from each other, though they are found to be distinct from
S. tani from Thailand and Malaysia, and also from S. suzukii from
Taiwan.
Conclusion
• Adler, P. H. & Crosskey, R. W. (2014). World blackflies (Diptera: Simuliidae): a
comprehensive revision of the taxonomic and geographical inventory [2014].
http://www.clemson.edu/cafls/biomia/pdfs/blackflyinventory.pdf
• Low, V. L., Adler, P. H., Takaoka, H., Ya’cob, Z., Lim, P. E., Tan, T. K., Lim, Y. A. L.,
Chen, C. D., Norma-Rashid, Y., & Sofian-Azirun, M. (2014). Mitochondrial DNA
markers reveal high genetic diversity but low genetic differentiation in the black fly
Simulium tani Takaoka & Davies along an elevational gradient in Malaysia. PloS ONE,
9(6), e100512.
References
Figure 1: Specimens
Collection*
Figure 2: Specimens
Figure 3: DNA
Extraction
Figure 4:
Polymerase
Chain Reaction
Figure 5: ElectrophoresisFigure 6: Band
Visualization
Figure 7: Data Analysis
Figure 8: Maximum Parsimony Phylogenetic
Tree COI
Figure 9: Maximum Parsimony Phylogenetic
Tree COII
DNA Analysis of Simulium tani
Species-Complex (Diptera: Simuliidae) from Vietnam