Displaying publications 81 - 100 of 131 in total

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  1. 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.
  2. A New Species of the Simulium (Simulium) argentipes Species-Group (Diptera: Simuliidae) From Taiwan, and Its Phylogenetic Relationships With Four Related Species
    Takaoka H, Low VL, Tan TK, Huang YT, Fukuda M, Ya'cob Z
    J Med Entomol, 2018 06 28;55(4):884-892.
    PMID: 29538704 DOI: 10.1093/jme/tjy028
    A new black fly species, Simulium haiduanense Takaoka, Low & Huang (Diptera: Simuliidae), is described on the basis of females, males, pupae, and mature larvae from Taiwan. This new species is placed in the Simulium argentipes species-group of the subgenus Simulium (Diptera: Simuliidae) and is characterized by the yellowish female legs, ovipositor valves rounded apically and with its inner margin concave, claw with a small subbasal tooth, male style without a basal protuberance, pupal gill with eight filaments, corbicular cocoon, and larval abdomen lacking paired protuberances. It represents the first record of the S. argentipes species-group from Taiwan. Taxonomic notes are given to separate this new species from all eight species in the same species-group. The phylogenetic relationships of this new species with four related species are presented.
  3. Five new species of the Simulium decuplum subgroup of the Simulium (Gomphostilbia) batoense species-group (Diptera: Simuliidae) from Thailand and their phylogenetic relationships
    Takaoka H, Srisuka W, Van Lun Low, Saeung A
    Acta Trop, 2018 Jun;182:271-284.
    PMID: 29551392 DOI: 10.1016/j.actatropica.2018.03.019
    Five new species of black flies, Simulium (Gomphostilbia) chiangraiense, S. (G.) huaikaeoense, S. (G.) khaokhoense, S. (G.) maeklangense, and S. (G.) pamiangense, are described based on adults, pupae and mature larvae from Thailand. These five species are similar to one another and are placed in the S. decuplum subgroup of the S. batoense species-group by having the male fore coxae darkened, ventral plate flat and transverse; pupal gill with 10 short filaments; and larval postgenal cleft deep approaching or reaching the posterior margin of the hypostoma. Simulium (G.) chiangraiense sp. nov. and S. (G.) pamiangense sp. nov. differ from the three other new species by the much longer pupal gill filaments and darkened dorsal surface of abdominal segments 1 and 2. Taxonomic notes are provided to distinguish these five new species from five other related species. The phylogenetic positions of these new species in the S. decuplum subgroup are presented based on the mitochondrial COI gene. Simulium (G.) pamiangense sp. nov. and S. (G.) huaikaeoense sp. nov. are highly similar to each other genetically, showing a sister relationship, though they are clearly different morphologically. On the contrary, S. (G.) khaokhoense sp. nov. is distantly positioned from S. (G.) huaikaeoense nov., though it is almost indistinguishable morphologically from the latter.
  4. Simulium (Gomphostilbia) lemborense, a new black fly species (Diptera: Simuliidae) from Flores, Indonesia
    Takaoka H, Sofian-Azirun M, Chen CD, Lau KW, Halim MR, Low VL, et al.
    Zootaxa, 2017 Feb 21;4236(1):zootaxa.4236.1.8.
    PMID: 28264343 DOI: 10.11646/zootaxa.4236.1.8
    Simulium (Gomphostilbia) lemborense sp. nov. is described based on adults, pupae and mature larvae from Flores, in the eastern part of the Sunda Archipelago, Indonesia. This new species is placed in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein, representing the most eastern distribution record for the group. This new species is characterized by a narrow female frons and pupal gill with eight filaments, of which two filaments of the ventral pair are three to four times as long as the six other filaments. Taxonomic notes are provided to distinguish this new species from related species.
  5. Morphotaxonomic revision of species-groups of Simulium (Simulium) (Diptera: Simuliidae) in the Oriental Region
    Takaoka H
    Zootaxa, 2017 Nov 24;4353(3):425-446.
    PMID: 29245496 DOI: 10.11646/zootaxa.4353.3.2
    Species of eight species-groups (seven named and one unnamed) of Simulium (Simulium) Latreille are revised chiefly based on the adult female and male genitalia. Four species-groups are each divided into more than two groups. Thus, the S. christophersi species-group is divided into two (S. christophersi and S. nebulicola species-groups), the S. griseifrons species-group into six (S. griseifrons, S. grossifilum, S. chungi, S. crocinum, S. indicum and S. yadongense species-groups), the S. malyschevi species-group into two (S. malyschevi and S. pavlovskii species-groups), and the S. melanopus species-group into three (S. melanopus, S. dumogaense and S. iridescens species-groups). The S. crassifilum species-group is merged with the S. variegatum species-group. Simulium fulvipes (Ono) of the former S. malyschevi species-group and S. dentastylum Yang, Chen & Luo of Simulium s. str. species unplaced to species-group are removed from the subgenus Simulium because their male styles are subequal in length to the coxites. A revised classification of species of the 15 species-groups including eight new species-groups of Simulium (Simulium) is presented. Keys to 20 species-groups of Simulium (Simulium) in the Oriental Region are provided for adult females and males.
  6. Blackfly vectors of zoonotic onchocerciasis in Japan
    Takaoka H, Fukuda M, Otsuka Y, Aoki C, Uni S, Bain O
    Med Vet Entomol, 2012 Dec;26(4):372-8.
    PMID: 22827756 DOI: 10.1111/j.1365-2915.2012.01023.x
    Studies of blackfly vectors of Onchocerca dewittei japonica Uni, Bain & Takaoka (Spirurida: Onchocercidae), a parasite of wild boar implicated in the aetiology of zoonotic onchocerciasis in Japan, and six other zoonotic Onchocerca species of this country are reviewed. Molecular identification of infective larvae found in wild-caught female blackflies showed that Simulium bidentatum (Shiraki) (Diptera: Simuliidae) is a natural vector of O. dewittei japonica, and also Onchocerca sp. sensu Fukuda et al., another parasite of wild boar. Inoculation experiments demonstrated that Simulium arakawae Matsumura and four other Simulium species are putative vectors. Similarly, S. arakawae, S. bidentatum and Simulium oitanum (Shiraki) are putative vectors of Onchocerca eberhardi Uni & Bain and Onchocerca skrjabini Rukhlyadev, parasites of sika deer. Morphometric studies of infective larvae indicated that Onchocerca lienalis Stiles, a bovine species, is transmitted by S. arakawae, Simulium daisense (Takahasi) and Simulium kyushuense Takaoka, and that Onchocerca sp. sensu Takaoka & Bain, another bovine species, is transmitted by S. arakawae, S. bidentatum, S. daisense and S. oitanum. Prosimulium sp. (Diptera: Simuliidae) and Simulium japonicum Matsumura are suspected vectors of Onchocerca suzukii Yagi, Bain & Shoho and O. skrjabini [Twinnia japonensis Rubtsov (Diptera: Simuliidae) may also transmit the latter], parasites of Japanese serow, following detection of the parasites' DNA genes in wild-caught blackflies.
  7. Morphological and genetic analyses of Simulium (Gomphostilbia) okinawense Takaoka and S. (G.) tokarense Takaoka (Diptera: Simuliidae) from the Nansei Islands, Japan: redescription and transfer from the S. ceylonicum species-group to the S. asakoae species-group
    Takaoka H, Otsuka Y, Fukuda M, Low VL, Ya'cob Z
    Trop Biomed, 2023 Mar 01;40(1):88-100.
    PMID: 37356008 DOI: 10.47665/tb.40.1.007
    Simulium (Gomphostilbia) okinawense Takaoka and S. (G.) tokarense Takaoka, both from the Nansei Islands, Japan, were morphologically reexamined and genetically analysed by using the COI gene sequences. The female, male, pupa and mature larva of the two species are redescribed. Morphological reexamination shows that both species are more similar to species in the S. asakoae species-group than to those in the S. ceylonicum species-group, by having a medium-long female sensory vesicle, yellow tuft hairs (S. (G.) okinawense) or yellow tuft hairs mixed with a few to several dark hairs (S. (G.) tokarense) at the base of the radial vein in the female and male, and medium-long larval postgenal cleft. However, the body of the male ventral plate (viewed ventrally) is parallel-sided (S. (G.) okinawense) or parallelsided or slightly narrowed (S. (G.) tokarense) and not emarginated basally, differing from those of most species in the S. asakoae species-group. Our genetic analysis shows that S. (G.) tokarense is in the S. asakoae species-group, and S. (G.) okinawense formed a separate sister clade with other members of the S. asakoae species-group with high bootstrap support. From the results of morphological and genetic analysis combined, S. (G.) okinawense and S. (G.) tokarense are transferred from the S. ceylonicum species-group to the S. asakoae species-group.
  8. Morphological redescription of Simulium takahasii (Rubtsov), the first species of the subgenus Wilhelmia Enderlein (Diptera: Simuliidae) recognized in East Asia
    Takaoka H, Otsuka Y, Fukuda M, Low VL, Ya'cob Z
    Trop Biomed, 2023 Jun 01;40(2):266-272.
    PMID: 37650416 DOI: 10.47665/tb.40.2.020
    Simulium takahasii (Rubtsov), which was originally described from Japan, and recorded from Korea and China, is the first among the 19 species of the subgenus Wilhelmia Enderlein recorded from East Asia. It is striking in mating, blood-feeding and ovipositing in captivity and in experimentally transmitting Dirofilaria immitis (Leidy) and Brugia pahangi (Buckley & Edeson), and it is a severe biter of cattle and horses, rarely of humans. Nevertheless, updated information about its morphological characteristics was lacking, making comparisons with related species described from China difficult, since species of the subgenus Wilhelmia are almost indistinguishable from one another, in particular, in their female terminalia, male genitalia and most of larval features. In this study, as many morphological characteristics as possible of S. takahasii based on specimens from Japan are redescribed. New information about many features of this species including the length of the female sensory vesicle against the third palpal segment, number of male upper-eye (large) facets, arrangement of the eight pupal gill filaments, presence or absence of tiny dark setae on the dorsum of the larval abdomen and the number of rows and hooklets of the larval posterior circlet will be useful in evaluating the species status of several Wilhelmia species in China including the species regarded as S. takahasii.
  9. Fulltext Twenty-one new species of the Simulium (Gomphostilbia) asakoae species group (Diptera, Simuliidae) in Thailand, with their genetic relationships
    Takaoka H, Srisuka W, Fukuda M, Saeung A
    Zookeys, 2020;950:51-152.
    PMID: 32774101 DOI: 10.3897/zookeys.950.51298
    Females and males reared from pupae, their pupal exuviae and cocoons, and mature larvae of the Simulium (Gomphostilbia) asakoae species group from various localities in Thailand were morphologically examined. A total of 25 species was identified, including two of four known species (Simulium asakoae Takaoka & Davies and S. chiangdaoense Takaoka & Srisuka), one newly confirmed species (S. myanmarense Takaoka, Srisuka & Saeung, originally described from Myanmar), one newly transferred species (S. inthanonense Takaoka & Suzuki formerly of the S. ceylonicum species group), and 21 new species. Descriptions of all 21 new species are given, and the first full description of the male of S. inthanonense, together with the revised descriptions of its female, pupa, and larva, is also provided. Keys to identify all 27 members of this species group from Thailand are given for females, males, pupae, and larvae. The genetic relationships of all but one species were resolved using COI gene sequence-based analysis. All 26 species were divided into nine subgroups, I-IX, each consisting of two, one, four, nine, one, three, two, one and three species, respectively.
  10. Fulltext Dimorphic male scutal patterns and upper-eye facets of Simulium mirum n. sp. (Diptera: Simuliidae) from Malaysia
    Takaoka H, Low VL, Sofian-Azirun M, Otsuka Y, Ya'cob Z, Chen CD, et al.
    Parasit Vectors, 2016;9:136.
    PMID: 26961508 DOI: 10.1186/s13071-016-1393-9
    A species of Simulium in the Simulium melanopus species-group of the subgenus Simulium (formerly misidentified as S. laterale Edwards from Sabah and Sarawak, Malaysia) is suspected to have dimorphic male scutal color patterns linked with different numbers of upper-eye facets. This study aimed to confirm whether or not these two forms of adult males represent a single species.
  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. 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.
  13. 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.
  14. 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.
  15. 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.
  16. 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.
  17. 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.
  18. 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.
  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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