Displaying publications 21 - 40 of 131 in total

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  1. Three Taxa in One: Cryptic Diversity in the Black Fly Simulium nobile (Diptera: Simuliidae) in Southeast Asia
    Low VL, Takaoka H, Pramual P, Adler PH, Ya'cob Z, Chen CD, et al.
    J Med Entomol, 2016 07;53(4):972-976.
    PMID: 27208009
    We access the molecular diversity of the black fly Simulium nobile De Mejiere, using the universal cytochrome c oxidase subunit I (COI) barcoding gene, across its distributional range in Southeast Asia. Our phylogenetic analyses recovered three well-supported mitochondrial lineages of S. nobile, suggesting the presence of cryptic species. Lineage A is composed of a population from Sabah, East Malaysia (Borneo); lineage B represents the type population from Java, Indonesia; and lineage C includes populations from the mainland of Southeast Asia (Peninsular Malaysia and Thailand). The genetic variation of lineage C on the mainland is greater than that of lineages A and B on the islands of Borneo and Java. Our study highlights the value of a molecular approach in assessing species status of simuliids in geographically distinct regions.
  2. Fulltext Delineating taxonomic boundaries in the largest species complex of black flies (Simuliidae) in the Oriental Region
    Low VL, Takaoka H, Pramual P, Adler PH, Ya'cob Z, Huang YT, et al.
    Sci Rep, 2016 Feb 03;6:20346.
    PMID: 26839292 DOI: 10.1038/srep20346
    Perspicuous assessments of taxonomic boundaries and discovery of cryptic taxa are of paramount importance in interpreting ecological and evolutionary phenomena among black flies (Simuliidae) and combating associated vector-borne diseases. Simulium tani Takaoka & Davies is the largest and perhaps the most taxonomically challenging species complex of black flies in the Oriental Region. We use a DNA sequence-based method to delineate currently recognized chromosomal and morphological taxa in the S. tani complex on the Southeast Asian mainland and Taiwan, while elucidating their phylogenetic relationships. A molecular approach using multiple genes, coupled with morphological and chromosomal data, supported recognition of cytoform K and morphoform 'b' as valid species; indicated that S. xuandei, cytoform L, and morphoform 'a' contain possible cryptic species; and suggested that cytoform B is in the early stages of reproductive isolation whereas lineage sorting is incomplete in cytoforms A, C, and G.
  3. Fulltext Tests of conspecificity for allopatric vectors: Simulium nodosum and Simulium shirakii (Diptera: Simuliidae) in Asia
    Low VL, Adler PH, Sofian-Azirun M, Srisuka W, Saeung A, Huang YT, et al.
    Parasit Vectors, 2015 May 29;8:297.
    PMID: 26022092 DOI: 10.1186/s13071-015-0911-5
    BACKGROUND: Allopatric populations present challenges for biologists working with vectors. We suggest that conspecificity can be concluded in these cases when data from four character sets-chromosomal, ecological, molecular, and morphological-express variation no greater between the allopatric populations than between corresponding sympatric populations. We use this approach to test the conspecificity of Simulium nodosum Puri on the mainland of Southeast Asia and Simulium shirakii Kono & Takahasi in Taiwan. The validity of these two putative species has long been disputed given that they are morphologically indistinguishable.

    FINDINGS: The mitochondria-encoded cytochrome c oxidase subunit I (COI), 12S rRNA, and 16S rRNA genes and the nuclear-encoded 28S rRNA gene support the conspecific status of S. nodosum from Myanmar, Thailand, and Vietnam and S. shirakii from Taiwan; 0 to 0.19 % genetic differences between the two taxa suggest intraspecific polymorphism. The banding patterns of the polytene chromosomes of the insular Taiwanese population of S. shirakii and mainland populations of S. nodosum are congruent. The overlapping ranges of habitat characteristics and hosts of S. nodosum and S. shirakii corroborate the chromosomal, molecular, and morphological data.

    CONCLUSIONS: Four independent sources of evidence (chromosomes, DNA, ecology, and morphology) support the conspecificity of S. nodosum and S. shirakii. We, therefore, synonymize S. shirakii with S. nodosum. This study provides a guide for applying the procedure of testing conspecificity to other sets of allopatric vectors.

  4. DNA Barcoding of Simulium asakoae (Diptera: Simuliidae) From Northern Thailand
    Low VL, Srisuka W, Saeung A, Tan TK, Ya'cob Z, Yeong YS, et al.
    J Med Entomol, 2020 09 07;57(5):1675-1678.
    PMID: 32333022 DOI: 10.1093/jme/tjaa081
    Previous studies suggested the presence of species complex in the so-called Simulium asakoae Takaoka & Davies (Diptera: Simuliidae) in Thailand due to its high morphological variability and genetic divergence. To investigate whether the true S. asakoae is present in Thailand, we performed a detailed morphological identification of S. asakoae and compared its DNA barcodes with the morphospecies S. asakoae from Myanmar and the typical S. asakoae from Malaysia. Phylogenetic analysis revealed the Thai materials analyzed in this study were indeed genetically similar with those from Myanmar and Malaysia, though genetic distances 0-2.27% were observed. We tentatively regard this divergence as intraspecific variation, and the automatic barcode gap discovery analysis further supports them as a single species.
  5. A novel molecular and chromosomal lineage of the anthropophilic Simulium (Simulium) rufibasis subgroup (Diptera: Simuliidae) in Taiwan
    Low VL, Takaoka H, Adler PH, Tan TK, Weng FC, Chen CY, et al.
    Parasitol Res, 2018 Oct;117(10):3137-3143.
    PMID: 30006809 DOI: 10.1007/s00436-018-6011-7
    The Simulium rufibasis subgroup is one of three subgroups of the Simulium (Simulium) tuberosum species-group; it is characterized by a pair of clustered stout hairs on the ventral surface of female abdominal segment 7. A member of the S. rufibasis subgroup in Taiwan was investigated morphologically and genetically using the universal cytochrome c oxidase subunit I (COI) barcoding gene and polytene chromosomal banding pattern. The Taiwanese material is morphologically similar to S. rosliramlii Takaoka & Chen from Vietnam and represents the second species of the S. rufibasis subgroup known from Taiwan. It also represents a novel molecular lineage that is distinct from three other primary lineages identified as S. doipuiense, S. doipuiense/S. rufibasis, and S. weji previously reported from Thailand. The mitochondrial evidence for a distinct lineage in Taiwan is supported by chromosomal analysis, which revealed unique sex chromosomes. For nomenclatural stability, we associate the name S. arisanum Shiraki with the Taiwanese entity. Originally described from females from Taiwan, S. arisanum until now has remained an enigmatic species.
  6. A multi-locus approach resolves the phylogenetic relationships of the Simulium asakoae and Simulium ceylonicum species groups in Malaysia: evidence for distinct evolutionary lineages
    Low VL, Takaoka H, Adler PH, Ya'cob Z, Norma-Rashid Y, Chen CD, et al.
    Med Vet Entomol, 2015 Sep;29(3):330-7.
    PMID: 25968459 DOI: 10.1111/mve.12120
    A multi-locus approach was used to examine the DNA sequences of 10 nominal species of blackfly in the Simulium subgenus Gomphostilbia (Diptera: Simuliidae) in Malaysia. Molecular data were acquired from partial DNA sequences of the mitochondria-encoded cytochrome c oxidase subunit I (COI), 12S rRNA and 16S rRNA genes, and the nuclear-encoded 18S rRNA and 28S rRNA genes. No single gene, nor the concatenated gene set, resolved all species or all relationships. However, all morphologically established species were supported by at least one gene. The multi-locus sequence analysis revealed two distinct evolutionary lineages, conforming to the morphotaxonomically recognized Simulium asakoae and Simulium ceylonicum species groups.
  7. Fulltext Redescription, molecular characterisation and Wolbachia endosymbionts of Mansonella (Tupainema) dunni (Mullin & Orihel, 1972) (Spirurida: Onchocercidae) from the common treeshrew Tupaia glis Diard & Duvaucel (Mammalia: Scandentia) in Peninsular Malaysia
    Mat Udin AS, Uni S, Rodrigues J, Martin C, Junker K, Agatsuma T, et al.
    Curr Res Parasitol Vector Borne Dis, 2024;5:100154.
    PMID: 38193019 DOI: 10.1016/j.crpvbd.2023.100154
    The genus Mansonella Faust, 1929 includes 29 species, mainly parasites of platyrrhine monkeys in South America and anthropoid apes in Africa. In Malaysia, Mansonella (Tupainema) dunni (Mullin & Orihel, 1972) was described from the common treeshrew Tupaia glis Diard & Duvaucel (Scandentia). In a recent classification of the genus Mansonella, seven subgenera were proposed, with M. (Tup.) dunni as a monotypic species in the subgenus Tupainema. In this study, we collected new material of M. (Tup.) dunni from common treeshrews in Peninsular Malaysia and redescribed the morphological features of this species. We found that M. (Tup.) dunni differs from M. (Cutifilaria) perforata Uni et al., 2004 from sika deer Cervus nippon (Cetartiodactyla) in Japan, with regards to morphological features and predilection sites in their respective hosts. Based on multi-locus sequence analyses, we examined the molecular phylogeny of M. (Tup.) dunni and its Wolbachia genotype. Species of the genus Mansonella grouped monophyletically in clade ONC5 and M. (Tup.) dunni was placed in the most derived position within this genus. Mansonella (Tup.) dunni was closely related to M. (M.) ozzardi (Manson, 1897) from humans in Central and South America, and most distant from M. (C.) perforata. The calculated p-distances between the cox1 gene sequences for M. (Tup.) dunni and its congeners were 13.09% for M. (M.) ozzardi and 15.6-16.15% for M. (C.) perforata. The molecular phylogeny of Mansonella spp. thus corroborates their morphological differences. We determined that M. (Tup.) dunni harbours Wolbachia endosymbionts of the supergroup F genotype, in keeping with all other Mansonella species screened to date.
  8. Cytogenetic and Molecular Evidence of Additional Cryptic Diversity in High Elevation Black fly Simulium feuerborni (Diptera: Simuliidae) Populations in Southeast Asia
    Pramual P, Thaijarern J, Sofian-Azirun M, Ya'cob Z, Hadi UK, Takaoka H
    J Med Entomol, 2015 Sep;52(5):829-36.
    PMID: 26336220 DOI: 10.1093/jme/tjv080
    Simulium feuerborni Edwards is geographically widespread in Southeast Asia. Previous cytogenetic study in Thailand revealed that this species is a species complex composed of two cytoforms (A and B). In this study, we cytologically examined specimens obtained from the Cameron Highlands, Malaysia, and Puncak, Java, Indonesia. The results revealed two additional cytoforms (C and D) of S. feuerborni. Specimens from Malaysia represent cytoform C, differentiated from other cytoforms by a fixed chromosome inversion on the long arm of chromosome III (IIIL-5). High frequencies of the B chromosome (33-83%) were also observed in this cytoform. Specimens from Indonesia represent the cytoform D. This cytoform is differentiated from others by a fixed chromosome inversion difference on the long arm of chromosome II (IIL-4). Mitochondrial DNA sequences support genetic differentiation among cytoforms A, B, and C. The pairwise F(ST) values among these cytoforms were highly significantly consistent with the divergent lineages of the cytoforms in a median-joining haplotype network. However, a lack of the sympatric populations prevented us from testing the species status of the cytoforms.
  9. From bites to barcodes: uncovering the hidden diversity of black flies (Diptera: Simuliidae) in Vietnam
    Putt QY, Ya'cob Z, Adler PH, Chen CD, Hew YX, Izwan-Anas N, et al.
    Parasit Vectors, 2023 Aug 07;16(1):266.
    PMID: 37545007 DOI: 10.1186/s13071-023-05892-0
    BACKGROUND: Prompt and precise identification of black flies (Simuliidae) is crucial, given their biting behaviour and significant impact on human and animal health. To address the challenges presented by morphology and chromosomes in black fly taxonomy, along with the limited availability of molecular data pertaining to the black fly fauna in Vietnam, this study employed DNA-based approaches. Specifically, we used mitochondrial and nuclear-encoded genes to distinguish nominal species of black flies in Vietnam.

    METHODS: In this study, 135 mitochondrial cytochrome c oxidase subunit I (COI) sequences were established for 45 species in the genus Simulium in Vietnam, encompassing three subgenera (Gomphostilbia, Nevermannia, and Simulium), with 64 paratypes of 27 species and 16 topotypes of six species. Of these COI sequences, 71, representing 27 species, are reported for the first time.

    RESULTS: Combined with GenBank sequences of specimens from Malaysia, Myanmar, Thailand, and Vietnam, a total of 234 DNA barcodes of 53 nominal species resulted in a 71% success rate for species identification. Species from the non-monophyletic Simulium asakoae, S. feuerborni, S. multistriatum, S. striatum, S. tuberosum, and S. variegatum species groups were associated with ambiguous or incorrect identifications. Pairwise distances, phylogenetics, and species delimitation analyses revealed a high level of cryptic diversity, with discovery of 15 cryptic taxa. The current study also revealed the limited utility of a fast-evolving nuclear gene, big zinc finger (BZF), in discriminating closely related, morphologically similar nominal species of the S. asakoae species group.

    CONCLUSION: This study represents the first comprehensive molecular genetic analysis of the black fly fauna in Vietnam to our knowledge, providing a foundation for future research. DNA barcoding exhibits varying levels of differentiating efficiency across species groups but is valuable in the discovery of cryptic diversity.

  10. Descriptions of the female and larva of Simulium (Gomphostilbia) udomi (Diptera: Simuliidae) from Thailand, and its transfer to the Simulium asakoae species-group
    Saeung A, Srisuka W, Low VL, Maleewong W, Takaoka H
    Acta Trop, 2017 Aug;172:14-19.
    PMID: 28433572 DOI: 10.1016/j.actatropica.2017.04.014
    The female and larva of Simulium (Gomphostilbia) udomi Takaoka & Choochote from Thailand are described for the first time. The female of this species is similar to those of S. (G.) asakoae Takaoka & Davies from Peninsular Malaysia, Thailand, Hong Kong and Vietnam, and S. (G.) chiangdaoense Takaoka & Srisuka from Thailand. The larva of this species is similar to S. (G.) curtatum Jitklang et al. and S. (G.) nr. asakoae 2 from Thailand in having a medium-long postgenal cleft. Taxonomic notes are given to separate this species from these related species. The COI gene sequence of S. (G.) udomi is compared with those of eight species of the S. asakoae species-group and three species of the S. ceylonicum species-group. This species is transferred from the S. ceylonicum species-group to the S. asakoae species-group based on the adult female and male morphological characters, comparisons of the genetic distances and phylogenetic relationships inferred from the COI gene sequences.
  11. Natural infections with larvae of Onchocerca species type I in the human-biting black fly, Simulium nigrogilvum (Diptera: Simuliidae), in western Thailand
    Saeung A, Srisuka W, Aupalee K, Fukuda M, Otsuka Y, Taai K, et al.
    Acta Trop, 2020 Apr;204:105344.
    PMID: 31954685 DOI: 10.1016/j.actatropica.2020.105344
    Zoonotic onchocerciasis is a human infection caused by Onchocerca species of animal origins and transmitted by black fly vectors. The reported incidence of this disease has increased throughout the world. This study aims to clarify the vectorial roles of black fly species in zoonotic filarial transmission in Tak province, western Thailand. The integrated approach of morphological and DNA sequence-based analyses was used to identify species of both wild-caught female black flies and infective filarial larvae found in the infected black flies. All of 494 female black flies captured were identified as Simulium nigrogilvum, through scanning electron microscopy (SEM) and DNA sequence analyses based on the cytochrome c oxidase subunit I (COI) and subunit II (COII), and the fast-evolving nuclear elongation complex protein 1 (ECP1) genes. Four females of S. nigrogilvum harbored one to three third-stage larvae (infective larvae) in their thoraces, with an infection rate of 0.81% (4/494). All infective larvae were similar in morphology and size to one another, being identified as Onchocerca species type I (= O. sp. type A), a bovine filaria, originally reported from Japan, and also as O. sp. found in S. nodosum in Thailand, based on their body lengths and widths being 1,068-1,346 µm long by 25-28 µm wide, and morphological characters. Comparisons of cytochrome c oxidase subunit I (COI) and 12S rRNA sequences of mitochondrial DNA (mtDNA) and phylogenetic analyses with those of previous reports strongly supported that all larvae were O. sp. type I. This report is the first indicating the presence of O. sp. type I in Thailand and its vector being S. nigrogilvum.
  12. Fulltext Seasonal biodiversity of black flies (Diptera: Simuliidae) and evaluation of ecological factors influencing species distribution at Doi Pha Hom Pok National Park, Thailand
    Srisuka W, Takaoka H, Otsuka Y, Fukuda M, Thongsahuan S, Taai K, et al.
    Acta Trop, 2015 Sep;149:212-9.
    PMID: 26028177 DOI: 10.1016/j.actatropica.2015.05.024
    This is the first study on the seasonal biodiversity of black flies and evaluation of ecological factors influencing their distribution at Doi Pha Hom Pok National Park, northern Thailand. Larvae were collected from six fixed-stream sites in relation to altitude gradients from May 2011 to April 2013. The water temperature, water pH, conductivity, total dissolved solids (TDS), salt, water velocity, stream width and depth, streambed particle sizes, riparian vegetation, and canopy cover were recorded from each site. Monthly collections from the six sites yielded 5475 last-instar larvae, belonging to 29 black fly species. The most frequently found species from all sites were Simulium asakoae (100%) followed by Simulium yuphae (83.3%), and Simulium chiangdaoense, Simulium gombakense, Simulium phahompokense, Simulium fruticosum, Simulium maeaiense and Simulium fenestratum (66.6%). Of the 5475 last-instar larvae, S. maeaiense (19.3%), S. chiangdaoense (15.8%) and S. asakoae (14.8%), were the three most abundant species. The Shannon diversity index (H) at the six sites with different altitudes of 2100m, 2000m, 1500m, 1400m, 700m, and 500m above mean sea level, were 2.042, 1.832, 2.158, 2.123, 1.821 and 1.822, respectively. The Shannon index and number of taxa in the cold season were higher than those in the rainy and hot seasons. Principal component analysis (PCA) indicated that at least three principal components have eigen values >1.0 and accounted for 93.5% of the total variability of ecological factors among sampling sites. The Canonical correspondence analyses (CCA) showed that most species had a trend towards altitude, canopy cover, riparian vegetation and water velocity.
  13. A new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from Northern Thailand, with its genetic relationship in the S. asakoae species-group
    Srisuka W, Aupalee K, Low VL, Yácob Z, Fukuda M, Saeung A, et al.
    Acta Trop, 2021 Jun;218:105889.
    PMID: 33722581 DOI: 10.1016/j.actatropica.2021.105889
    A new black fly species, Simulium (Gomphostilbia) kiewlomense, is described from females, males, pupae and mature larvae in Thailand. This new species is placed in the S. asakoae species-group and is characterized by having a combination of the elongate female sensory vesicle, widened male hind basitarsus, which is much wider than the hind femur, small pupal terminal hooks, and light greenish larval abdominal segments 1-3. Taxonomic notes are given to separate this new species from other related species. A DNA analysis using the COI gene shows that this new species has two genoforms with 1.21% difference. This is the 28th species of the S. asakoae species-group in Thailand, strengthening the evidence for high species diversity of this species-group.
  14. Fulltext Community Structure, Biodiversity and Spatiotemporal Distribution of the Black Flies (Diptera: Simuliidae) Using Malaise Traps on the Highest Mountain in Thailand
    Srisuka W, Sulin C, Aupalee K, Phankaen T, Taai K, Thongsahuan S, et al.
    Insects, 2021 May 31;12(6).
    PMID: 34072677 DOI: 10.3390/insects12060504
    Black flies form a group of small blood-sucking insects of medical and veterinary importance. This study aimed to investigate the community structure, biodiversity and spatial and temporal distribution of adult black flies in tropical rain forests, by using malaise traps in Doi Inthanon National Park, northern Thailand. Malaise traps were placed along six elevational gradients (400 m to 2500 m, above sea level) at Doi Inthanon National Park, Chiang Mai province, from December 2013 to November 2014. A total of 9406 adult female black flies belonging to five subgenera-Daviesellum (2%), Gomphostilbia (23%), Montisimulium (11%), Nevermannia (16%) and Simulium (48%)-were collected. Among 44 taxa found, S. tenebrosum complex had the highest relative abundance (11.1%), followed by the S. asakoae species-group (9.6%), the S. striatum species-group (7.7%), S. inthanonense (6.6%), S. doipuiense complex (6.4%), S. chomthongense complex (5.3%), S. chumpornense (5.1%) and S. nigrogilvum (4.1%). Two human-biting species-S. nigrogilvum and species in the S. asakoae species-group-were found in all of the collection sites with 100% species occurrence. Species richness was highest at mid elevation (1400 m), which is represented by 19 black fly species. The peak and lowest seasonal abundance was observed in the rainy and hot season, respectively. Seasonal species richness was highest in the cold season, except for that from elevation sites at 700 m, 1700 m and 2500 m. This study revealed that the malaise trap is effective in providing important data for further monitoring of the effects of environmental changes and conservation planning on the biodiversity of black flies in Doi Inthanon National Park.
  15. Fulltext Description of male, pupa and larva of Simulium (Asiosimulium) wanchaii (Diptera: Simuliidae) from Thailand, with keys to identify four species of the subgenus Asiosimulium
    Srisuka W, Takaoka H, Saeung A
    Trop Biomed, 2015 Sep;32(3):504-10.
    PMID: 26695212 MyJurnal
    The male, pupa and mature larva of Simulium (Asiosimulium) wanchaii Takaoka & Choochote, one of the four species of the small Oriental black fly subgenus Asiosimulium, are described for the first time based on samples collected from Thailand. The male S. (A.) wanchaii is characterized based on the enlarged hind basitarsus and the ventral plate which is much wider than long. The pupa and larva are characterized by the gill with 19 filaments and the deep postgenal cleft, respectively. Keys are provided to identify all the four species of the subgenus Asiosimulium for females, males, pupae and mature larvae.
  16. A new species of the Simulium (Gomphostilbia) (Diptera: Simuliidae) from Thailand, with its phylogenetic relationships with related species in the Simulium asakoae species-group
    Srisuka W, Takaoka H, Fukuda M, Otsuka Y, Saeung A
    Acta Trop, 2019 Sep;197:105043.
    PMID: 31153893 DOI: 10.1016/j.actatropica.2019.105043
    A new species of black fly, Simulium (Gomphostilbia) rampae, is described, based on adult male, its pupal exuviae and mature larvae collected from Doi Inthanon National Park, northern Thailand. This new species is placed in the Simulium asakoae species-group, and is characterized in the male by the high number of upper-eye facets in 17 vertical columns and 18 horizontal rows, in the pupa by the gill with a long common basal stalk, cone-shaped terminal hook, and cocoon with an anterodorsal projection, and in the larva by the medium-long postgenal cleft. A DNA analysis using COI gene supported its assignment to the S. asakoae species-group and showed its close relationship to S. (G.) udomi Takaoka & Choochote and S. (G.) chiangdaoense Takaoka & Srisuka. This is the fourth member of the S. asakoae species-group recorded from Thailand.
  17. Morphological description and phylogenetic position of a new cryptic species in the Simulium asakoae species-group, Simulium (Gomphostilbia) mokroense, from Western Thailand
    Srisuka W, Aupalee K, Fukuda M, Saeung A, Takaoka H
    Acta Trop, 2022 Jan 14;228:106313.
    PMID: 35038426 DOI: 10.1016/j.actatropica.2022.106313
    Adult females and males reared from pupae of Simulium sp. from Tak Province and those of S. chiangdaoense Takaoka & Srisuka from four localities in Chiang Mai and Lampang Provinces, northern Thailand, were molecularly and morphologically compared. Simulium sp. is morphologically almost indistinguishable from S. chiangdaoense except the hair tuft at the base of the radius of the adult female and male, which is composed of yellow and dark hairs (in place of yellow hairs only). Molecular analysis using COI gene sequences shows that S. sp. formed a distinct clade and was separated from S. chiangdaoense by a genetic distance of 1.56-2.44%. Based on the results of morphological and molecular analyzes, S. sp. is described as a new species, S. mokroense, from females, males, pupae and mature larvae. It is also found that S. chiangdaoense is genetically diverse, with five lineages, and is morphologically variable in the number of male upper-eye (large) facets, which are in 13 to 17 vertical columns and 14 to 17 horizontal rows on each side. This is a first case, in which the difference in the color of the wing tuft hairs is a clue leading to the discovery of a new cryptic species close to S. chiangdaoense.
  18. Discovery of a new black fly species in the Simulium (Simulium) striatum species-group (Diptera: Simuliidae) from northeastern Thailand and its phylogenetic relationships with seven Thai related species
    Srisuka W, Takaoka H, Aupalee K, Saeung A
    Acta Trop, 2023 Feb;238:106790.
    PMID: 36473597 DOI: 10.1016/j.actatropica.2022.106790
    The female, male, pupa and mature larva of Simulium (Simulium) poolpholi sp. nov. collected from a large and seasonal stream in northeastern Thailand are described. This new species is placed in the S. striatum species-group by the female sternite 8 concave posteromedially in form of the inverted-U shape, ovipositor valve with a ventrally produced process along its inner margin, male ventral plate saddle-shaped, style with a basal protuberance, and pupal gill with 10 filaments. It is morphologically similar to S. (S.) phraense Takaoka, Srisuka & Saeung from northern Thailand by lacking annular ridges on the surface of pupal gill filaments but it is distinguished from the latter species by the arrangement of pupal gill filaments. Molecular analysis using the fast-evolving nuclear big zinc finger (BZF) gene shows that S. (S.) poolpholi sp. nov. formed a distinct clade, being separated from the seven other Thai species of this species-group by a genetic distance of 1.84-4.55%. Our discovery increases the number of species in the S. striatum species-group in Thailand to nine.
  19. Simulium (Gomphostilbia) wijiti, a new species of black fly (Diptera: Simuliidae) from northern Thailand and its genetic position with related species in the Simulium ceylonicum species-group
    Srisuka W, Takaoka H, Aupalee K, Saeung A
    Acta Trop, 2023 Aug;244:106947.
    PMID: 37196907 DOI: 10.1016/j.actatropica.2023.106947
    A new black fly species, Simulium (Gomphostilbia) wijiti, is described based on adult females, males, pupal exuviae and mature larvae from Mae Hong Son Province, Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from four Thai members of the S. ceylonicum species-group [S. (G.) curtatum Jitklang et al., S. (G.) pangsidaense Takaoka, Srisuka & Saeung, S. (G.) sheilae Takaoka & Davies, and S. (G.) trangense Jitklang et al.], in the female by the short to medium long sensory vesicle; in the male by the large number of upper-eye (large) facets in 15 vertical columns and 15 or 16 horizontal rows; in the pupa by the dorsum of abdominal segments darkened; and in the larva by the antenna as long as or slightly shorter than the stem of the labral fan (longer than the stem of the labral fan in four other species). Phylogenetic analysis based on the COI gene sequences revealed that this new species is genetically closely related to S. leparense of the S. ceylonicum species-group, but is clearly separated from the latter species, and also from the three Thai related species (S. curtatum, S. sheilae and S. trangense) of the same species-group with interspecific genetic distances ranging from 9.65% to 12.67%. This is the fifth member of the S. ceylonicum species-group recorded from Thailand.
  20. Fulltext Biodiversity, seasonal abundance, and distribution of blackflies (Diptera: Simuliidae) in six different regions of Thailand
    Srisuka W, Takaoka H, Otsuka Y, Fukuda M, Thongsahuan S, Taai K, et al.
    Parasit Vectors, 2017 Nov 21;10(1):574.
    PMID: 29157269 DOI: 10.1186/s13071-017-2492-y
    BACKGROUND: Blackflies are an important medical and veterinary group of small blood-sucking insects. Ninety-three blackfly species have been reported in Thailand. However, information on their biodiversity and population dynamics in each region is lacking. The main aim of this study was to assess the regional biodiversity, seasonal abundance and distribution of blackflies in six eco-geographically different regions in the country.

    METHODS: Blackfly larvae and pupae were sampled monthly from 58 sites between May 2011 and April 2013. Diversity parameters, seasonal abundance, regional distribution and frequency of species occurrence in stream sites were analyzed.

    RESULTS: A total of 19,456 mature larvae representing 57 species, and belonging to six subgenera in the genus Simulium Latreille (s.l.), were found. The five predominant taxa were S. fenestratum (8.6%), the S. asakoae complex (8.3%), S. nakhonense (7.5%), the S. siamense complex (7.4%) and the S. doipuiense complex (6.7%). The most frequent taxa at all sites were the S. asakoae complex (84.5%), followed by S. fenestratum (82.8%), the S. siamense complex (75.9%), S. decuplum (60.3%), S. nakhonense (58.6%) and the S. tani complex (48.3%). The richness of regional species was highest (40 species) in the north and predominated in the cold season. However, blackflies in the south predominated during the hot season. The highest numbers of blackflies collected from central, northeastern, eastern and western regions of the country were observed in the rainy season. Overall, the mean number of blackflies collected across the six regions during the rainy and cold season had no statistically significant difference, but it differed significantly in the hot season.

    CONCLUSIONS: Blackflies in Thailand were surveyed in all three seasons across six geographical regions. These findings demonstrated that blackfly communities at each stream site varied with seasonality, and the regional relative abundance of blackflies differed markedly in the hot season. It was also found that the occurrence and distribution of blackflies in each region were associated strongly with elevation.

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