Displaying publications 21 - 40 of 45 in total

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  1. Two new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from Myanmar, and their phylogenetic relationships with related species in the S. asakoae species-group
    Takaoka H, Srisuka W, Low VL, Maleewong W, Saeung A
    Acta Trop, 2017 Dec;176:39-50.
    PMID: 28746824 DOI: 10.1016/j.actatropica.2017.07.024
    Two new species of Simulium (Gomphostilbia), S. (G.) myanmarense and S. (G.) monglaense, are described from females, males, pupae and larvae from Myanmar. The two new species are placed in the S. asakoae species-group, and are similar to each other in the female and male but distinguished in the pupa by the presence or absence of an anterodorsal projection of the cocoon, and in the larva by a unique pattern of colored markings on the abdomen. Taxonomic notes are given to separate these species from related species. The COI gene sequences of both species are compared with those of eight species of the S. asakoae species-group and three species of the S. ceylonicum species-group. Both new species are most closely related to each other, further supporting their morphological classification in the S. asakoae species-group.
  2. Morphological and Molecular Evidence for Multiple Taxa in Simulium parahiyangum (Diptera: Simuliidae), a Geographic Generalist Black Fly in Southeast Asia
    Takaoka H, Low VL, Srisuka W, Ya'cob Z, Saeung A
    J Med Entomol, 2018 Oct 25;55(6):1453-1463.
    PMID: 30060220 DOI: 10.1093/jme/tjy109
    Seven populations of Simulium parahiyangum Takaoka & Sigit (Diptera: Simuliidae), a geographically widespread nominal species of black fly in Southeast Asia, were morphologically and molecularly studied. Three morphoforms based on male and pupal morphological features, and two primary lineages based on the COI gene sequence analysis were recognized. Morphoform 1 (lineage 1) from Sarawak, Malaysia, is identified as S. parahiyangum sensu stricto and morphoform 2 (lineage 2) from Thailand and Vietnam, and morphoform 3 (lineage 1) from Peninsular Malaysia are each regarded as distinct species, although morphoform 3 is partially homosequential for the COI gene with morphoform 1. Morphoforms 2 and 3 are described as Simulium ngaoense sp. nov. and Simulium sazalyi sp. nov., respectively. Overall, S. parahiyangum is not a single geographic generalist but a composite of multiple species.
  3. A New Species of the Simulium (Simulium) multistriatum Species-Group (Diptera: Simuliidae) From Thailand and Its Phylogenetic Relationships With Related Species
    Takaoka H, Srisuka W, Low VL, Saeung A
    J Med Entomol, 2019 01 08;56(1):86-94.
    PMID: 30398648 DOI: 10.1093/jme/tjy178
    Simulium undecimum sp. nov. is described from Thailand. This new species is assigned to the Simulium multistriatum species-group, one of the 20 species-groups of the subgenus Simulium in the Oriental Region. It is characterized by the female cibarium with minute processes, male ventral plate with a narrow body having two vertical rows of distinct teeth on the posterior surface and without setae on the anterior and lateral surfaces, pupal gill with eight short filaments decreasing in length from dorsal to ventral, and divergent at an angle of around 90 degrees when viewed laterally, spine-combs only on abdominal segments 7 and 8, and cocoon wall-pocket shaped with anterolateral windows. Taxonomic notes to separate this new species from related species in Thailand and other countries are given. This new species is the 11th nominal member of this species-group recorded in Thailand. An analysis of the COI gene sequences shows that it is most closely related with S. malayense Takaoka & Davies (cytoform A) from Thailand but they are distantly separated by 3.01-8.87%.
  4. Morphological and Molecular Analyses of Simulium rufibasis (Diptera: Simuliidae) in Thailand
    Takaoka H, Srisuka W, Low VL, Saeung A
    J Med Entomol, 2019 02 25;56(2):408-415.
    PMID: 30398654 DOI: 10.1093/jme/tjy180
    A man-biting black fly species so far regarded as Simulium rufibasis Brunetti in Thailand was morphologically analyzed. It was found to be almost indistinguishable in the female from S. rufibasis sensu stricto but distinguishable in the male by the slender fore basitarsus and abdominal segments 2, 6, and 7 each with a pair of shiny dorsolateral patches, and in the pupa by the absence of spine-combs on abdominal segment 7 and terminal hooks on segment 9. It is described as a new species, Simulium tenebrosum. Taxonomic notes are given to separate it from all 11 known species of the S. rufibasis subgroup of the Simulium (Simulium) tuberosum species-group. An analysis of the COI gene sequences shows that this new species is distantly separated from the closely related species.
  5. 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.
  6. 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.
  7. A New Black Fly Species of Simulium (Gomphostilbia) (Diptera: Simuliidae) From Laos
    Takaoka H, Srisuka W, Saeung A, Maleewong W, Low VL
    J Med Entomol, 2017 11 07;54(6):1543-1551.
    PMID: 28968910 DOI: 10.1093/jme/tjx134
    Simulium (Gomphostilbia) laosense sp. nov. is described based on adults, pupae, and mature larvae from Laos. This new species is placed in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein. It is characterized by the pupal gill with eight filaments arranged as 3 + 3 + 2 from dorsal to ventral, of which an inner filament of the ventral pair is slightly longer than its counter filament, and is 1.7-1.8 times as long as filaments of the middle triplet. Taxonomic notes are provided to distinguish this new species from Simulium (G.) johorense Takaoka, Sofian-Azirun & Ya'cob from Peninsular Malaysia and four other related species. The phylogenetic position of this new species in the S. batoense species-group is also presented based on the mitochondrial COI gene. This new species represents the second species known from Laos.
  8. A new black fly species of the Simulium (Gomphostilbia) epistum species-group (Diptera: Simuliidae) from Thailand
    Takaoka H, Srisuka W, Low VL, Saeung A
    Acta Trop, 2017 Dec;176:373-379.
    PMID: 28919444 DOI: 10.1016/j.actatropica.2017.09.006
    A new species of black fly, Simulium (Gomphostilbia) isanense, is described based on females, males, pupae and mature larvae from Thailand. This new species is placed in the Simulium epistum species-group of the subgenus Gomphostilbia Enderlein. It is characterized by the pupal gill with eight filaments arranged as 3+3+2 from dorsal to ventral, of which an inner filament of the ventral pair is slightly longer than its counter filament. Taxonomic notes are provided to distinguish this new species from S. (G.) angulistylum Takaoka & Davies from Peninsular Malaysia, and three other related species. The difference between this new species and S. (G.) angulistylum is supported by genetic distances using the mitochondrial COI gene.
  9. A New Species of the Simulium (Simulium) striatum Species Group (Diptera: Simuliidae) from Thailand, and Its Differentiation from Two Related Species Based on a Fast-Evolving Nuclear Gene
    Takaoka H, Srisuka W, Low VL, Saeung A
    J Med Entomol, 2018 05 04;55(3):561-568.
    PMID: 29361011 DOI: 10.1093/jme/tjx241
    Simulium (Simulium) phraense sp. nov. (Diptera: Simuliidae) is described from females, males, pupae, and larvae from Thailand. This new species is placed in the Simulium striatum species group and is most similar to Simulium (Simulium) nakhonense Takaoka & Suzuki (Diptera: Simuliidae) from Thailand among species of the same species group but is barely distinguished from the latter species by lacking annular ridges on the surface of the pupal gill filaments. The fast-evolving nuclear big zinc finger (BZF) gene has successfully differentiated this new species from its allies, S. (S.) nakhonense and Simulium (Simulium) chiangmaiense Takaoka & Suzuki (Diptera: Simuliidae) of the S. striatum species group. The BZF gene sequences show that this new species is more closely related to S. (S.) nakhonense than to S. (S.) chiangmaiense, further supporting its morphological classification.
  10. A new species of Simulium (Asiosimulium) (Diptera: Simuliidae) from northeastern Thailand, with its phylogenetic relationships with related species in the subgenus Asiosimulium
    Aupalee K, Srisuka W, Taai K, Takaoka H, Saeung A
    J Med Entomol, 2023 Nov 14;60(6):1330-1342.
    PMID: 37669777 DOI: 10.1093/jme/tjad118
    Simulium (Asiosimulium) khongchiamense sp. nov. is described based on females, males, pupae, and mature larvae collected from Khong Chiam District, Ubon Ratchathani Province, northeastern Thailand. It is characterized in the female by the medium-long sensory vesicle, scutum with 3 dark longitudinal vittae and elongate cercus; in the male by the number of upper-eye (large) facets in 17 or 18 vertical rows and 18 or 19 horizontal rows, hind basitarsus moderately enlarged and ventral plate with the posterior margin moderately concave medially; in the pupa by the head and thoracic integument sparsely covered with tubercles and gill of arborescent type with 32 or 33 filaments; and in the larva by the postgenal cleft deep, reaching the posterior margin of the hypostoma and sheath of the subesophageal ganglion dark pigmented. DNA analysis based on COI gene of all known species of the subgenus Asiosimulium, except for S. shanense and S. suchitrae, indicated that this new species can be clearly differentiated from all other related species (S. phurueaense, S. oblongum, S. saeungae, S. furvum, and S. wanchaii) with interspecific genetic distances ranging between 4.79% and 19.18%. This is the eighth species of the subgenus Asiosimulium. Taxonomic notes are given to distinguish this new species from the 7 known species members in its same subgenus. Additionally, keys to species of all members in the subgenus Asiosimulium are provided.
  11. 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.
  12. Fulltext Seasonal Filarial Infections and Their Black Fly Vectors in Chiang Mai Province, Northern Thailand
    Aupalee K, Saeung A, Srisuka W, Fukuda M, Streit A, Takaoka H
    Pathogens, 2020 Jun 25;9(6).
    PMID: 32630410 DOI: 10.3390/pathogens9060512
    The transmission of zoonotic filarial parasites by black flies has so far been reported in the Chiang Mai and Tak provinces, Thailand, and the bites of these infected black flies can cause a rare disease-human zoonotic onchocerciasis. However, species identification of the filarial parasites and their black fly vectors in the Chiang Mai province were previously only based on a morphotaxonomic analysis. In this study, a combined approach of morphotaxonomic and molecular analyses (mitochondrial cox1, 12S rRNA, and nuclear 18S rRNA (SSU HVR-I) genes) was used to clarify the natural filarial infections in female black flies collected by using human and swine baits from two study areas (Ban Lek and Ban Pang Dang) in the Chiang Mai province from March 2018 to January 2019. A total of 805 and 4597 adult females, belonging to seven and nine black fly taxa, were collected from Ban Lek and Ban Pang Dang, respectively. At Ban Lek, four of the 309 adult females of Simulium nigrogilvum were positive for Onchocerca species type I in the hot and rainy seasons. At Ban Pang Dang, five unknown filarial larvae (belonging to the same new species) were detected in Simulium sp. in the S. varicorne species-group and in three species in the S. asakoae species-group in all seasons, and three non-filarial larvae of three different taxa were also found in three females of the S. asakoae species-group. This study is the first to molecularly identify new filarial species and their vector black fly species in Thailand.
  13. 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.
  14. Three new species of the Simulium (Simulium) striatum species-group (Diptera: Simuliidae) from Thailand, with their phylogenetic relationships
    Aupalee K, Saeung A, Srisuka W, Fukuda M, Junkum A, Pitasawat B, et al.
    Acta Trop, 2020 Nov;211:105625.
    PMID: 32649996 DOI: 10.1016/j.actatropica.2020.105625
    Three new species of black flies from Thailand, Simulium wangkwaiense, S. tadtonense and S. maeklongkeense, are described based on their adults, pupal exuviae and cocoons. All three new species are assigned to the Simulium (Simulium) striatum species-group, bringing its total number in Thailand to seven. Simulium wangkwaiense sp. nov. is the species formerly called S. quinquestriatum in Thailand. Certain male and pupal morphological characteristics are shown to separate all seven Thai species of this species-group. All of the three new species have been analyzed genetically for their phylogenetic relationships, with three known related species (except for S. thailandicum), by using the fast-evolving nuclear big zinc finger (BZF) gene.
  15. 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.
  16. 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.
  17. A method for distinguishing the important malaria vectors Anopheles dirus and An. cracens (Diptera: Culicidae) based on antennal sensilla of adult females
    Taai K, Harbach RE, Somboon P, Sriwichai P, Aupalee K, Srisuka W, et al.
    Trop Biomed, 2019 Dec 01;36(4):926-937.
    PMID: 33597464
    Some species of the Anopheles dirus species complex are considered to be highly competent malaria vectors in Southeast Asia. Anopheles dirus is the primary vector of Plasmodium falciparum and P. vivax while An. cracens is the main vector of P. knowlesi. However, these two species are difficult to distinguish and identify based on morphological characters. Hence, the aim of this study was to investigate the potential use of antennal sensilla to distinguish them. Large sensilla coeloconica borne on the antennae of adult females were counted under a compound light microscope and the different types of antennal sensilla were examined in a scanning electron microscope. The antennae of both species bear five types of sensilla: ampullacea, basiconica, chaetica, coeloconica and trichodea. Observations revealed that the mean numbers of large sensilla coeloconica on antennal flagellomeres 2, 3, 7, 10 and 12 on both antennae of both species were significantly different. This study is the first to describe the types of antennal sensilla and to discover the usefulness of the large coeloconic sensilla for distinguishing the two species. The discovery provides a simple, reliable and inexpensive method for distinguishing them.
  18. 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.
  19. 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.

  20. Fulltext A new species of Simulium (Gomphostilbia) (Diptera, Simuliidae) from Thailand, with a key to identify females of 14 species of the Simuliumvaricorne species-group
    Srisuka W, Aupalee K, Otsuka Y, Fukuda M, Takaoka H, Saeung A
    Zookeys, 2022;1083:1-12.
    PMID: 35115871 DOI: 10.3897/zookeys.1083.77428
    Simulium (Gomphostilbia) khelangensesp. nov. is described on the basis of females, collected by a sweeping net in Lampang, Phitsanulok and Chiang Mai Provinces, Thailand. This new species is placed in the S.chumpornense subgroup of the S.varicorne species-group in the subgenus Gomphostilbia Enderlein by having the antenna with eight flagellomeres, pleural membrane bare, and female subcosta lacking hairs. It is similar to S.kuvangkadilokae Pramual & Tangkawanit from Thailand in the same subgroup but is barely distinguished from the latter species by the head width relative to the greatest width of the frons and length of the labrum relative to the clypeus. A genetic analysis using the COI gene sequences similarly shows that S.khelangense sp. nov. is most closely related to S.kuvangkadilokae, with a genetic distance of 1.23-2.81%. A revised key to identify females of 14 species of the S.varicorne species-group is provided.
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