To investigate the breeding habitat preference of black flies, a comprehensive black fly survey was conducted for the first time in Peninsular Malaysia. Preimaginal black flies (pupae and larvae) were collected manually from 180 stream points encompassing northern, southern, central and east coast of the Peninsular Malaysia. A total of 47 black fly species were recorded in this study. The predominant species were Simulium trangense (36.7%) and Simulium angulistylum (33.3%). Relatively common species were Simulium cheongi (29.4%), Simulium tani (25.6%), Simulium nobile (16.2%), Simulium sheilae (14.5%) and Simulium bishopi (10.6%). Principal Component Analysis (PCA) of all stream variables revealed four PCs that accounted for 69.3% of the total intersite variance. Regression analysis revealed that high species richness is associated with larger, deeper, faster and higher discharge streams with larger streambed particles, more riparian vegetation and low pH (F=22.7, d.f.=1, 173; P<0.001). Relationship between species occurrence of seven common species (present in >10% of the sampling sites) was assessed. Forward logistic regression analysis indicated that four species were significantly related to the stream variables. S. nobile and S. tani prefer large, fast flowing streams with higher pH, large streambed particles and riparian trees. S. bishopi was commonly found at high elevation with cooler stream, low conductivity, higher conductivity and more riparian trees. In contrast, S. sheilae was negatively correlated with PC-2, thus, this species commonly found at low elevation, warmer stream with low conductivity and less riparian trees. The results of this study are consistent with previous studies from other geographic regions, which indicated that both physical and chemical stream conditions are the key factors for black fly ecology.
A new species of black fly, Simulium (Simulium) luculentum, is described from specimens collected in Thailand, and is assigned to the Simulium variegatum species-group of the subgenus Simulium Latreille. This new species is distinguished from most members of this species group in the female by the mid femur and tibia entirely yellowish; and in the pupa by the gill with six filaments, which are somewhat inflated basally. This species represents the fifth member of the S. variegatum species-group recorded from Thailand.
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.
A new black fly species, Simulium (Gomphostilbia) pangsidaense, is described on the basis of adult female, male, pupal exuviae and mature larvae from Pang Sida National Park, Sa Kaew Province, Eastern Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from three Thai members of the S. ceylonicum species-group by the following characteristics: from S. (G.) curtatum Jitklang et al. and S. (G.) sheilae Takaoka & Davies by the wide pupal terminal hooks (triangular terminal hooks in the latter two species), and from S. (G.) sheilae and S. (G.) trangense Jitklang et al. by the number of male upper-eye facets in 13 vertical columns and 14 or 15 horizontal rows (10 or 11 vertical columns and 12 or 13 horizontal rows in the latter two species). This is the fourth member of the S. ceylonicum species-group recorded from Thailand.
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.
Simulium (Simulium) hackeri Edwards, 1928 of the Simulium variegatum species-group from Malaysia was described initially based on the female specimen from Cameron Highlands, Pahang. In the present study, the pupa and larva of this species are described for the first time. Their morphological characters resemble those of the Simulium variegatum species-group by having six gill filaments per side, abdomen with dorsal spine-combs at least on segments 7 and 8, cocoon with wall-pocket shaped and with or without an anterodorsal projection. Postgenal cleft of the larva medium-sized, rarely small, ventral papillae small or absent. The DNA barcode of this species is also reported herein.
Larvae and adults reared from pupae of Simulium (Gomphostilbia) gombakense Takaoka & Davies from eight streams in five provinces of Thailand were genetically analyzed by using cytochrome c oxidase subunit 1 sequences. The material was composed of four lineages, of which lineages 2, 3 and 4 are genetically closely related to one another, but more distantly related to lineage 1, which is equivalent to typical S. (G.) gombakense from Peninsular Malaysia. Lineages 2, 3 and 4, which are morphologically indistinguishable, are designated as genoforms A, B and C within a species complex of S. (G.) paiense sp. nov., which is described based on specimens of lineage 2 (=genoform A). Simulium (G.) paiense sp. nov. is similar to S. (G.) gombakense from Peninsular Malaysia but appears to be barely distinguished by the relative length of the female fore basitarsus. Simulium (G.) thuathienense Takaoka & Sofian-Azirun is newly recorded from Thailand and its male is described for the first time. The female of S. (G.) gombakense is briefly described based on females reared from pupae collected from Peninsular Malaysia.
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.
A black fly species of the Simulium feuerborni species-group of Simulium (Nevermannia) from Cameron Highland, Peninsular Malaysia, previously regarded as S. feuerborni Edwards, originally described from East Java, is described as Simulium pairoti sp. nov. based on complete life stages. High intraspecific variations in the arrangement of the six pupal gill filaments, length of the stalk of the ventral paired filaments, and length of the anterodorsal projection of the cocoon, are noted in this species. This new species is readily distinguished from its congeners by having the characters of male genitalia with simple lamellate ventral plate, short inwardly-twisted styles, several parameral hooks, and a simple narrow median sclerite. Morphological data reported herein plus the chromosomal and molecular data presented elsewhere support S. pairoti as a novel pseudocryptic species.
In recent decades, the numbers of cryptic taxa have increased significantly with current progress in DNA barcoding, yet, most of these cryptic taxa have not been formally named and recognized as valid species. To address this issue, we provide a guide for applying the procedure of describing new cryptic species in the family Simuliidae. Simulium (Simulium) vanluni from Pahang, Peninsular Malaysia, previously treated as S. nobile De Meijere, is described as a new species by using an integrated morpho-taxonomical and genetic approach. This new species is morphologically identical to S. nobile from Java and S. kiuliense Smart & Clifford from Borneo, but their distinctiveness is supported by an expanded multigene phylogeny analysis.
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.
Two new black fly species, Simulium (Gomphostilbia) kaohsiungense and S. (G.) shoufengense, are described from females, males and pupae in Taiwan. These new species are placed in the S. asakoae species-group. Simulium (G.) kaohsiungense sp. nov. is characterized by a combination of the elongate female sensory vesicle, male upper-eye (large) facets in 15 vertical columns and 15 or 16 horizontal rows, male hind basitarsus 1.02-1.15 times the width of the hind femur, and widened pupal terminal hooks. These characteristics distinguish this new species from most species of the S. asakoae species-group. Simulium (G.) shoufengense sp. nov. is similar in the female and male to S. (G.) asakoae Takaoka & Davies originally described from Peninsular Malaysia but is distinguished from the latter species in the pupa by the combined length of the primary and secondary stalks of the dorsal triplet of gill filaments as long as or longer than the common basal stalk of the gill, and dorsum of abdominal segments 1 and 2 not darkened. The species previously regarded in Taiwan as S. (G.) metatarsale Brunetti, originally described from India, is morphologically and molecularly identified as S. (G.) asakoae.
The species status of two cytoforms of two species complexes in the Simulium (Simulium) tuberosum species-group, which are almost indistinguishable in the pupal stage, was morphologically and genetically evaluated. Cytoform 'L' of the S. (S.) tani Takaoka & Davies complex, previously recognized as S. (S.) suzukii Rubtsov in Taiwan, is described as a new species, S. (S.) jianshiense. It is morphologically distinguishable as adults from two members of the S. (S.) suzukii complex: cytoform 'C' from Hokkaido, selected to represent the type of S. (S.) suzukii sensu stricto, and cytoform 'D' from Okinawa Island and, based on our chromosomal analysis, also from Amami Island. This new species is genetically separated from both cytoforms of the S. (S.) suzukii complex with a genetic distance of 5.31-6.67%. Cytoform 'D' is distinguished from cytoform 'C' by the color of the male forecoxa and relative length of the female sensory vesicle to the third maxillary palpomere. Accordingly, the name S. (S.) ryukyuense Ogata, once regarded as a synonym of S. (S.) suzukii, is revalidated and applied to cytoform 'D'. The genetic distance between S. (S.) ryukyuense and S. (S.) suzukii sensu stricto is 1.24-1.60%.
Simulium (Gomphostilbia) omutaense Ogata & Sasa, 1954 is the only named species in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein recorded from Honshu and Kyushu, Japan. It represents the northernmost distribution of this species-group, of which most members are distributed in the Oriental region. This species, the only member of the Simulium omutaense subgroup, is unique among the seven subgroups of the S. batoense species-group by having the pupal gill with one long filament and seven short filaments, similar to the arrangement of the pupal gill filaments in the S. zonatum subgroup of the S. epistum species-group in the same subgenus. This species is fully redescribed based on adults, pupal exuviae and mature larvae, and is most similar to species of the S. decuplum subgroup, based on adult morphological characteristics, although the pupal gill of the latter subgroup is markedly different by having 10 or 12 short filaments. Its close relationship to the S. decuplum subgroup is supported by a DNA analysis using COI gene sequences, with genetic distances of 9.30-11.02%. On the other hand, genetic distances between S. (G.) omutaense and species of the S. zonatum subgroup were 16.32-16.93%. Our study shows that a similar arrangement of the pupal gills in two different species-groups, which is rarely seen, has evolved independently and its occurrence does not necessarily reflect phylogenetic relationships.
A faunistic survey of black flies in Shan State, central Myanmar, was carried out in 2013. A total of 16 species were collected, of which 13 species are newly recorded from Myanmar. Among 13 newly recorded species, S. (S.) chiangmaiense Takaoka & Suzuki varied in the number of pupal gill filaments from eight to 10. This survey increases the number of species of black flies from Myanmar from 8 to 23. They are classified in five subgenera of the genus Simulium: one in Asiosimulium, seven in Gomphostilbia, one in Montisimulium, two in Nevermannia and 12 in Simulium.
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.
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.
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.
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.
An estimated 13 million people in the Oriental Region have brugian filariasis. The filarial parasites that cause this disease exist in periodic and sub-periodic forms and are transmitted by four genera of mosquito: Anopheles, Mansonia and, less frequently, Coquillettidia and Ochlerotatus. In most endemic countries, control of the disease has been entirely based on chemotherapy, although house-spraying and use of insecticide-treated bednets can be quite effective against the vectors of nocturnally periodic Brugia malayi and B. timori. The vector-control methods that may be applied against the Mansonia mosquitoes that transmit the parasites causing sub-periodic brugian filariasis are reviewed here. Most of the conventional methods for controlling the immature, aquatic stages of mosquitoes have proved unsatisfactory against Mansonia. The reason is that, unlike the those of other genera, the larvae and pupae of Mansonia spp. are relatively immobile and obtain air not at the water surface but from the underwater roots, stems and leaves of floating plants to which the larvae and pupae attach. Removal of host plants can be very effective in reducing Mansonia productivity, whereas large-scale use of herbicides is restricted by the potential adverse effects on the ecosystem. Environmental management in water-development projects remains the best option.