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[4 new species of blackflies (Diptera: Simuliidae) from Central Asia, Siberia and the Far East].

Four new species of blackflies (Diptera: Simuliidae) are described. Helodon rezidentsii Yankovsky, sp. n., Khabarovsk Territory, differs from all known species of the genus with morphology of eyes consisting only of microommatidii in male; from related species H. kamtshaticus (Rubzov, 1940) with large triangular posteromedial lobes of branches of genital fork in female; with number of rays of primary fan of premandibles (20-22, when in H. kamtshaticus 30-32) in larva. Helodon submulticaulis Yankovsky, sp. n., Transbaikalia, differs from related species H. multicaulis (Popov, 1968) with number of rays of primary fan of mandibles (36-40, when in H. multicaulis 26-28), narrow anterior branches of anal sclerite, number of rows of hooks in posterior attachment organ (88-92, when in H. multicaulis 78-80) in larva; with morphology of respiratory organ, consisting of 5-8 lobes bearing 40-60 tune filaments (in H. multicaulis 3-4 lobes bearing more than 150 filaments) in pupa. Sch. samarkandica Yankovsky, sp. n., Uzbekistan, differs from related species Sch. pseudopusilla Rubzov, 1956 with 3 (not 2 as in Sch. pseudopusilla) hooks in parameres, bifurcated lateral branches of X sternite, long projection of gonostyles in male. Schoenbaueria ivdelensis Yankovsky, sp. n., Middle Ural, differs from related species Sch. rangiferina (Rubzov, 1956) with prolonged gonostyles bearing narrow projection in male; with number of rays of secondary fan of premandibles (20-28, when in Sch. rangiferina 44-48), deep ventral groove of cephalic capsule, number of rows of hooks in posterior attachment organ (80-82, when in Sch. rangiferina 70-72) in larva; with morphology of respiratory organ (very long stems of 2 and 3 pairs of filaments) in pupa.

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[5 new species of blackflies (Diptera: Simuliidae) from Siberia, the Far East and Central Asia].

Five new species of the family Simuliidae Stegopterna byrrangii Yankovsky, sp. n. and Cnephia chaurensis Yankovsky sp. n., from Taimyr peninsula, Metacnephia olyutorii Yankovsky sp. n. from Kamchatka, Metacnephia karakechensis Yankovsky sp. n. and Montisimulium sonkulense Yankovsky sp. n. from Kirghizia, are described. Stegopterna byrrangii differs from related species: in male--from all known species of the genus by peculiar form of apical end of gonostyles, when apical spine is approximately parallel to inner surface of gonostyle; in female--from all known species of the genus by very long genital lobes (their length twice more than width), from S. longicoxa Rubzov, 1971 and S. duodecimata (Rubzov, 1940) by long stem of genital fork, absence of anterolateral sclerotized projections of branches of genital fork; in pupa--from all known species of the genus by number of filaments of respiratory organ (14-16, when in other species no more than 12). Cnephia chaurensis differs from related species: in male--from C. intermedia Rubzov, 1956 and C. toptchievi Yankovsky, 1996 by absence of medial projection or ridge of gonosternum, from C. intermedia by widened body of gonosternum, from C. toptchievi by ridge on gonocoxites and wide triangular projections near base of arms of gonosternum; in female--from C. intermedia by sclerotized finger-like anterolateral projections of branches of genital fork, subdivision of branches into two lobes, wide flat apical end of stem of genital fork. Metacnephia karakechensis differs from related species: in male--from M. subalpina (Rubzov, 1956) by form of gonostyles, absence of triangular medial projection of gonosternum, short widened gonofurca and more number of spines in parameres, from M. kirjanovae (Rubzov, 1956) and M. slepjani (Rubzov, 1967) by triangular body of gonosternum, widened gonostyles, more number of spines in parameres; in larva--from M. subalpina by more number of rays of primary fan of premandibles, less number of ridges of hooks in posterior attachment organ, from M. kirjanovae by short thick antennae; in pupa--from M. subalpina by character of divergence of upper thick filaments of respiratory organ, from M. kirjanovae by presence of thick filaments of the organ. Metacnephia olyutorii differs from related species: in female--from M. larunae Worobez, 1984 and M. aldanica Worobez, 1987 by thick sclerotized anterolateral projections of branches of genital fork, from M. taimyrica Patrusheva, 1976 by 1-ended (not 3-ended) anterolateral projections of branches of genital fork, large (not shortened) anal lobes, from M. crassifistula (Rubzov, 1956) by very long stem of genital fork. Montisimulium sonkulense differs from related species: in male--from M. brachystylum (Rubzov, 1976) by more prolonged gonostyles, less number of spines of parameres, from M. ocreastylum (Rubzov, 1956) by form of gonostyles, from M. odontostylum (Rubzov, 1947) by more number of spines of parameres; in female--from M. brachystylum and M. odontostylum by stricktly developed posteromedial projections of branches of genital fork, from species having posteromedical projections of branches of genital fork--from M. (ABSTRACT TRUNCATED)

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[Small-scale evaluation of the efficacy of growth-regulating insecticides on larvae of the Simulium damnosum complex (Diptera: Simuliidae)].

The efficacy of insect growth regulators was assessed in small scale tests on larvae of the Simulium damnosum complex (Diptera: Simuliidae) in the Ivory Coast. Three compounds [OMS 2015 (triflumuron), OMS 3009 (teflubenzuron), OMS 3013 (chlorfluazuron)] belong to the group of benzoylphenyl-urea substitutes; these IGR's are supposed to inhibit chitin synthesis. Two other compounds are Juvenile Hormone Analogs (JHA's) (OMS 3007 and OMS 3019). The last compound (OMS 3010) is a phenoxycarbamate. The first three compounds had a low efficacy on blackfly larvae, which is consistent with the literature data for another compound of this group: diflubenzuron. The other three compounds (OMS 3007, OMS 3010 and OMS 3019) were much more efficient, OMS 3010 and OMS 3019 showing high activity at low concentrations. These results would justify further studies on the effect of larval age and exposure parameters, and eventually full scale river tests.

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The development of Onchocerca ochengi in surrogate temperate Simuliidae, with a note on the infective larva.

Laboratory reared nulliparous female flies of six temperate species of Simuliidae were examined for their susceptibility to infection with Onchocerca ochengi by intrathoracic injection of cryopreserved skin microfilariae obtained from cattle in Mali. Three species (S. equinum, S. ornatum and S. erythrocephalum) supported development to the infective stage, one species (S. variegatum) allowed partial development and the remaining two species (S. reptans and S. aureum) were insusceptible to infection. The most suitable surrogate vectors were S. equinum and S. ornatum which had survival rates of 44% and 49%, proportions of microfilariae developing to third stage larvae of 6.4% and 3%, and infection rates with infective larvae of 13.5% and 14% respectively. O. volvulus infective larvae, produced by intrathoracic microfilarial injection in S. ornatum, were 586-760 microns (mean 687 microns) long and were significantly shorter (p less than 0.02) than the O. ochengi infective larvae (645-880 microns, mean 756 microns). No constant differences in the posterior or anterior morphology, or in the acid phosphatase staining patterns between O. ochengi and O. volvulus, were seen. These results raise the possibility that the presence of O. ochengi in a population of infective larvae from vector flies in endemic onchocerciasis zones might be identifiable on the basis of their length alone.

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[Attack of black flies (Diptera, Simuliidae) on horses in Basel (Switzerland)].

In April 1996 an attack of black flies (Diptera, Simuliidae) to horses was observed in the region of Basle, Switzerland. Females of Simulium erythrocephalum and Simulium ornatum were involved in this attack, part of them had taken a blood meal. For S. ornatum this is the first record in Switzerland that this species takes blood meals on horses.

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Sex-linked inversions in blackflies (Diptera:Simuliidae).

The family Simuliidae exhibits a diversity of sex-linked inversions which fall into four major classes. Inversions occur which are found only in the X or Y, and these may be fixed or polymorphic. Y-linkage is clearly commoner amongst such inversions. Other inversions are found which phylogenetic evidence suggests cannot have been sex-linked in ancestral species, but have become so in derived forms. Lastly, inversions are found which occur on both sex chromosomes, but at different frequencies.

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A simplified membrane technique for feeding blackflies (Diptera: Simuliidae) on blood in the laboratory.

In order to overcome the difficulties of colonizing Simuliidae in the laboratory, a membrane system has been developed which was successfully used to feed Simulium vittatum and S. verecundum on out-dated human whole blood. Thirty-seven (41.1%) of 90 S. vittatum and 4 (8.6%) of 46 S. verecundum took blood meals in 6 trials. The membrane system was also shown to be more effective and consistent in providing blood meals compared with the use of laboratory animals.

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[New evidence for mass reproduction of midges (Diptera, Simuliidae) in the Voronezh Region].

In the forest-steppe zones, the bloodsucking dipterans--midges (Diptera, Simuliidae)--tend to drastically increase in size, which poses medical and veterinary problems (the toxic saliva administered into the victim's body on blood sucking causes diseases in man, disability, and even animals' death). According to our data, the role of dominating bloodsuckers varies in different districts of the Voronezh Region, depending on their Iocal conditions (the types of water systems and landscapes).

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A method of rearing Simulium damnosum Theobald (Diptera; Simuliidae) under artificial conditions.

The Simuliidae have proved particularly difficult to maintain under artificial conditions, and have resisted all attempts at laboratory colonization. Although a number of species have been successfully reared from egg to adult under laboratory conditions in certain northern countries, the problem of rearing African blackflies has been subjected to less intensive investigation. The development of suitable techniques for rearing and maintaining the vectors of human onchocerciasis in the laboratory would facilitate critical work on many aspects of vector biology.The vectors of human onchocerciasis in Africa belong to either the Simulium neavei or the S. damnosum complexes. During the present investigation large numbers of a nonanthropophilic form of S. damnosum were successfully reared from egg to adult under artificial conditions described in this paper. The method needs to be tested, however, with the anthropophilic forms within the S. damnosum complex responsible for transmission of onchocerciasis.

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Molecular identification of onchocerciasis vector sibling species in black flies (Diptera: Simuliidae).

A number of sibling species in the Simulium damnosum species complex transmit River Blindness (onchocerciasis) in tropical Africa. Black fly sibling species can be reliably recognized only through analysis of the larval polytene chromosomes. The routine, unambiguous assignment of the potentially disease-transmitting adult females to a particular species is virtually impossible. Two molecular assays to identify the sibling species of biting female flies are presented. The first relies on PCR-mediated amplification of internal transcribed spacers of the nuclear rDNA loci while the second involves immunoblotting of silk proteins which are expressed in both larvae and adult females. Both assays yield sibling-specific size markers that can be used to identify the sibling species of biting adult females. To illustrate the use of these assays, a molecular characterization is given for two S. damnosum siblings (squamosum, sirbanum) collected from cytologically verified populations, and a partial characterization of a third sibling (damnosum s. str.) found as a contaminant in these samples.

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Molecular characterization and taxonomy of a new species of Caudosporidae (Microsporidia) from black flies (diptera: simuliidae) with host-derived relationships of the North American caudosporids.

A new species of microsporidium, Caudospora palustris (Microsporidia: Caudosporidae), is described from 3 species of black flies (Cnephia ornithophilia and diploid and triploid cytospecies of Stegopterna mutata), bringing to 7 the total species of caudosporids recorded from North America. This new species of caudosporid is recorded from swamp streams of the Coastal Plain from New Jersey to Georgia, with single records from the New Jersey mountains and the Upper Peninsula of Michigan. Densities of patently infected larvae (up to 10,600/m2) and spore production (nearly 8x10(11)/m2) are the greatest recorded for any microsporidium of black flies. The ultrastructure of this new species is presented, along with the first molecular characterization for a microsporidium of black flies. The phylogenetic position of black fly microsporidia within the phylum Microsporidia is presented; however, the analysis does not support the inclusion of C. palustris in any clade. Key features of all North American caudosporids are provided, and possible evolutionary trajectories are proposed based on optimization of caudosporid species on the phylogeny of their 22 known host species, including 16 that represent new host species records.

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Phylogeny of sibling species of Simulium venustum and S. verecundum (Diptera: Simuliidae) based on sequences of the mitochondrial 16S rRNA gene.

The phylogeny of four sibling species of Simulium venustum (CC, CC3, CC4, and AC(gB)) and two sibling species of S. verecundum (AA and ACD = S. rostratum) was reconstructed using nucleotide sequences of the mitochondrial large subunit rRNA gene. Separate phylogenetic analyses were performed by dividing the sequence data into: (1) helices of a computer-generated secondary structure of the rDNA; (2) loops of the computer-generated structure; (3) helices of a consensus secondary structure (deduced by comparing the computer-generated structure of black flies with the corresponding structures proposed for the fruit fly (Drosophila yakuba) and the mosquito (Aedes albopictus)); (4) loops of the consensus structure; (5) both helices and loops of the consensus secondary structure; and (6) the entire sequence regardless of secondary structure, including 11 variable sites in regions where the prediction of secondary structure was not possible. We found that different data sets led to different phylogenetic conclusions. The phylogenies based on data sets 4 and 6 were consistent with nonmolecular evidence, while the phylogenies based on other data sets were not. Our study suggests S. decorum, a morphospecies, might have shared a common ancestor with sibling species of S. venustum.

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Polytene chromosomes of an archipelagic subgenus, Inseliellum (Diptera: Simuliidae).

The black fly subgenus Inseliellum is present on a series of archipelagos in the South Pacific. In this study, larval polytene chromosome maps of six Inseliellum species are presented. Chromosomal relationships among taxa were determined through shared fixed inversions or chromosomal landmark positioning. Three fixed inversions (IL-2, IIS-1, and IIIS-1) were shared among species, as was the position of the nucleolar organizer (NO) (IL or IIL). Comparisons to two previously studied species of Inseliellum are included to produce a cytological transformation series among eight taxa. The NO position defines two clades in the phylogeny of Inseliellum, herein named the NO-IL and NO-IIL clades. The utility of this cytological data set is discussed.

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Molecular phylogeny of black flies (Diptera: Simuliidae) from Thailand, using ITS2 rDNA.

The sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) were determined for 40 black fly species from Thailand, belonging to 4 subgenera of the genus Simulium, namely Gomphostilbia (12 species), Nevermannia (5 species), Montisimulium (1 species), Simulium sensu stricto (21 species), and an unknown subgenus with one species (Simulium baimaii). The length of the ITS2 ranged from 247 to 308 bp. All black fly species had high AT content, ranging from 71 to 83.8%. Intraindividual variation (clonal variation) occurred in 13 species, ranging from 0.3 to 1.1%. Large intrapopulation and interpopulation heterogeneities exist in S. feuerboni from the same and different locations in Doi Inthanon National Park, northern Thailand. Phylogenetic relationships among 40 black fly species were examined using PAUP (version 4.0b10) and MrBAYS (version 3.0B4). The topology of the trees revealed two major monophyletic clades. The subgenus Simulium and Simulium baimaii were placed in the first monophyletic clade, whereas the subgenera Nevermannia + Montisimulium were placed as the sister group to the subgenus Gomphostilbia in the second monophyletic clade. Our results suggest that S. baimaii belongs to the malyschevi-group or variegatum-group in the subgenus Simulium. The molecular phylogeny generally agrees with existing morphology-based phylogenies.

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