-
PloS One 2016A macrogenomic investigation of a Holarctic clade of black flies-the Simulium cholodkovskii lineage-provided a platform to explore the implications of a unique,...
A macrogenomic investigation of a Holarctic clade of black flies-the Simulium cholodkovskii lineage-provided a platform to explore the implications of a unique, synapomorphic whole-arm interchange in the evolution of black flies. Nearly 60 structural rearrangements were discovered in the polytene complement of the lineage, including 15 common to all 138 analyzed individuals, relative to the central sequence for the entire subgenus Simulium. Three species were represented, of which two Palearctic entities (Simulium cholodkovskii and S. decimatum) were sympatric; an absence of hybrids confirmed their reproductive isolation. A third (Nearctic) entity had nonhomologous sex chromosomes, relative to the other species, and is considered a separate species, for which the name Simulium nigricoxum is revalidated. A cytophylogeny is inferred and indicates that the two Palearctic taxa are sister species and these, in turn, are the sister group of the Nearctic species. The rise of the S. cholodkovskii lineage encompassed complex chromosomal and genomic restructuring phenomena associated with speciation in black flies, viz. expression of one and the same rearrangement as polymorphic, fixed, or sex linked in different species; taxon-specific differentiation of sex chromosomes; and reciprocal translocation of chromosome arms. The translocation is hypothesized to have occurred early in male spermatogonia, with the translocated chromosomal complement being transmitted to the X- and Y-bearing sperm during spermatogenesis, resulting in alternate disjunction of viable F1 translocation heterozygotes and the eventual formation of more viable and selectable F2 translocation homozygous progeny. Of 11 or 12 independently derived whole-arm interchanges known in the family Simuliidae, at least six are associated with subsequent speciation events, suggesting a facilitating role of translocations in adaptive radiations. The findings are discussed in the context of potential structural and functional interactions for future genomic research.
Topics: Animals; Biological Evolution; Chromosome Mapping; Chromosomes, Insect; Female; Genetic Linkage; Male; Phylogeny; Polytene Chromosomes; Radiation Tolerance; Simuliidae; Translocation, Genetic
PubMed: 27348428
DOI: 10.1371/journal.pone.0158272 -
Acta Tropica Jul 2021Although the microbiome of blood-feeding insects serves an integral role in host physiology, both beneficial and pathogenic, little is known of the microbial community...
Although the microbiome of blood-feeding insects serves an integral role in host physiology, both beneficial and pathogenic, little is known of the microbial community of black flies. An investigation, therefore, was undertaken to identify culturable bacteria from one of Malaysia's most common black flies, Simulium tani Takaoka and Davies, using 16S rDNA sequencing, and then evaluate the isolates for antibiotic resistance and virulence genes. A total of 20 isolates representing 11 bacterial species in four genera were found. Five isolates showed β-hemolysis on Columbia agar, and virulence genes were found in three of these isolates. Some degree of resistance to six of the 12 tested antibiotics was found among the isolates. The baseline data from this study suggest rich opportunities for comparative studies exploring the diversity and roles of the microbiome of S. tani and other Southeast Asian black flies.
Topics: Animals; Bacteria; Culture Techniques; Drug Resistance, Bacterial; Larva; RNA, Ribosomal, 16S; Simuliidae
PubMed: 33878305
DOI: 10.1016/j.actatropica.2021.105923 -
Parasitology Research Aug 2019Simulium dermatitis is an IgE-mediated skin reaction in animals and humans caused by the bites of black flies. Although Simulium nigrogilvum has been incriminated as the...
Simulium dermatitis is an IgE-mediated skin reaction in animals and humans caused by the bites of black flies. Although Simulium nigrogilvum has been incriminated as the main human-biting black fly species in Thailand, information on its salivary allergens is lacking. Salivary gland extract of S. nigrogilvum females was subjected to sodium dodecylsulfate-polyacrylamide gel electrophoresis, and the separated components were applied onto nitrocellulose membranes for immunoblotting, which was performed by probing the protein blots with sera from 17 individuals who were allergic to the bites of S. nigrogilvum. IgE-reactive protein bands were characterized further by liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Nine protein bands (79, 42, 32, 25, 24, 22, 15, 13, and 11 kDa) were recognized in the serum of the subjects. Four of the nine protein bands (32, 24, 15, and 11 kDa) showed IgE reactivity in all (100%) of the tested sera, and they were identified as salivary secreted antigen 5-related protein, salivary serine protease, erythema protein, and hypothetical secreted protein, respectively. Three other proteins, salivary serine protease (25 kDa), salivary D7 secreted protein (22 kDa), and hypothetical protein (13 kDa), reacted with > 50% of the sera. The relevance of the identified protein bands as allergens needs to be confirmed by using pure recombinant proteins, either in the in vivo skin prick test or in vitro detection of the specific IgE in the serum samples of allergic subjects. This will be useful for the rational design of component-resolved diagnosis and allergen immunotherapy for the allergy mediated by the bites of black flies.
Topics: Allergens; Animals; Bites and Stings; Chromatography, Liquid; Electrophoresis, Polyacrylamide Gel; Female; Galectin 3; Humans; Immunoglobulin E; Insect Proteins; Salivary Glands; Simuliidae; Tandem Mass Spectrometry; Thailand
PubMed: 31263951
DOI: 10.1007/s00436-019-06383-x -
Acta Tropica Dec 2021The species status of two cytoforms of two species complexes in the Simulium (Simulium) tuberosum species-group, which are almost indistinguishable in the pupal stage,...
Morphological and genetic revision of cytoform 'L' of the Simulium (Simulium) tani complex from Taiwan, and cytoform 'D' of the S. (S.) suzukii complex (Diptera: Simuliidae) from the Nansei Islands, Japan.
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%.
Topics: Animals; Female; Islands; Japan; Male; Pupa; Simuliidae; Taiwan
PubMed: 34508715
DOI: 10.1016/j.actatropica.2021.106124 -
Tropical Biomedicine Jun 2022Simulium (Gomphostilbia) ogatai (Rubtsov) from Japan, the only Palaearctic species in the S. ceylonicum species-group, is morphologically revised. Its female is...
Simulium (Gomphostilbia) ogatai (Rubtsov) from Japan, the only Palaearctic species in the S. ceylonicum species-group, is morphologically revised. Its female is described for the first time and its male and pupa are redescribed based on specimens from Gifu, Honshu. It is characterized in the female and male by the base of the radius with a tuft of yellow hairs, in the female by the head slightly wider than the thorax, 5.89 times as wide as the greatest width of the frons, and short sensory vesicle 0.21-0.24 times as long as the third palpal segment; in the male by the number of upper-eye (large) facets in 15 vertical columns and 16 horizontal rows, and hind basitarsus spindle-shaped, enlarged, 3.79 times as long as wide, and 0.83 and 1.00 times as wide as the greatest width of the hind tibia and femur, respectively; and in the pupa by the terminal hooks simple and cone-like, and the cocoon with an anterodorsal projection. Taxonomic notes for this species are given relevant to several related species in the Oriental Region, and its assignment to the S. ceylonicum species-group is confirmed.
Topics: Animals; Female; Japan; Larva; Male; Pupa; Simuliidae
PubMed: 35838096
DOI: 10.47665/tb.39.2.012 -
Acta Tropica Nov 2019Accurate species identification provides the foundation for successful pest management and vector control of black flies. Accordingly, we examined the mitochondrial DNA...
Accurate species identification provides the foundation for successful pest management and vector control of black flies. Accordingly, we examined the mitochondrial DNA cytochrome oxidase I (COI) gene sequences of four morphologically and chromosomally identified species of black flies (Simulium vernumgroup sp., S. bergi Rubtsov, S. bezzii (Corti), and S. kiritshenkoi Rubtsov) in Northeast Anatolia Region of Turkey where simuliid pest problems and simuliotoxicosis cases have been reported among cattle. COI gene sequences of these species and closely related species available in GenBank were used to provide species-level diagnoses and infer relationships. Both subgenera (Nevermannia and Simulium) were monophyletic, and subclades generally corresponded with species groups. Intraspecific genetic divergence was 0.2-1.6%, whereas the mean interspecific genetic divergence among the four species was 11.2-14.5%. The COI analysis produced results congruent with morphological concepts of the nominal species S. bergi and S. bezzii. Probable misidentifications in GenBank were revealed, especially for species in the S. ornatum and S. vernum groups, complicating identification capability. Sequence variation in the COI barcode region also might not be adequate for species delineation and identification among some species in these two species groups.
Topics: Animals; DNA Barcoding, Taxonomic; Disease Outbreaks; Electron Transport Complex IV; Haplotypes; Phylogeny; Simuliidae; Turkey
PubMed: 31422094
DOI: 10.1016/j.actatropica.2019.105149 -
Tropical Biomedicine Sep 2020Simulium (Simulium) contractum Takaoka from Sulawesi, Indonesia was known only as the pupa. Its female, male and mature larva are described for the first time. The...
Simulium (Simulium) contractum Takaoka from Sulawesi, Indonesia was known only as the pupa. Its female, male and mature larva are described for the first time. The tentative assignment of this species in the Simulium dumogaense species-group is confirmed by the adult characters including the female and male genitalia. The female and male of this species are similar to those of Simulium (Simulium) tumpaense Takaoka and Roberts but are distinguished by the yellowish femora.
Topics: Animals; Female; Indonesia; Larva; Male; Simuliidae
PubMed: 33612782
DOI: 10.47665/tb.37.3.683 -
Acta Tropica Nov 2020Three new species of black flies from Thailand, Simulium wangkwaiense, S. tadtonense and S. maeklongkeense, are described based on their adults, pupal exuviae and...
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.
Topics: Animals; Female; Larva; Male; Phylogeny; Pupa; Simuliidae; Species Specificity; Thailand
PubMed: 32649996
DOI: 10.1016/j.actatropica.2020.105625 -
Acta Tropica May 2020High-mountain summits in tropical regions are habitat islands that provide refugia for northern taxa and opportunities for speciation. These focal hotspots of...
High-mountain summits in tropical regions are habitat islands that provide refugia for northern taxa and opportunities for speciation. These focal hotspots of biodiversity are also threatened by increasing anthropogenic pressures and changing climatic conditions. The largest species group of black flies, the Simulium vernum group, reaches its southern limit in the mountains of Southeast Asia, providing an opportunity to examine macrogenetic diversification at the southern edge of the group's range. We investigated the polytene chromosomes of two morphologically similar species in the S. vernum group, S. chomthongense Takaoka, Srisuka & Choochote, and S. khunklangense Takaoka & Srisuka, from their type localities near the summit of Doi Inthanon, Thailand's highest mountain. Chromosomal analyses of 112 larvae demonstrated reproductive isolation between S. chomthongense and S. khunklangense and revealed a cryptic species of S. chomthongense. The three species have the same fixed banding sequence in five of the six chromosome arms, but they are distinguished by the successive addition of overlapping inversions in the IIIL arm. The two cytospecies (A and B) of S. chomthongense s. l. are the third example of endemic or nearly endemic cryptic species pairs near the top of Doi Inthanon, suggesting the possibility of sympatric speciation and the importance of conserving high-elevation stream habitats.
Topics: Animals; Biodiversity; Genetic Variation; Larva; Polytene Chromosomes; Simuliidae; Species Specificity; Thailand
PubMed: 32061626
DOI: 10.1016/j.actatropica.2020.105393 -
International Journal of Biological... Jan 2019The mitochondrial (mt) genome of the black fly Simulium (Byssodon) maculatum, a pest of great importance for both humans and livestock, is sequenced and annotated for...
The mitochondrial (mt) genome of the black fly Simulium (Byssodon) maculatum, a pest of great importance for both humans and livestock, is sequenced and annotated for the first time. The genome structure, gene order and codon usage are typical among Diptera mt genomes. The mt genome is circular and 15,799 bp in length with 13 protein coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and a control region (CR), and with weakly positive AT-skew (0.02) and negative GC-skew (-0.12). Phylogenetic relationships of 16 species representing five families of Culicomorpha and two outgroups, based on mt genome data, were analyzed using both Maximum Likelihood and Bayesian methods. The monophyly of Culicomorpha is well supported, while Chironomoidea is indicated as a paraphyletic group. The well supported monophyletic Simuliidae is the sister group to Culicidae.
Topics: Animals; Base Composition; Codon; Genome, Mitochondrial; Phylogeny; Simuliidae
PubMed: 30287375
DOI: 10.1016/j.ijbiomac.2018.09.205