ELETROPHORETIC CHARACTERIZATIONS OF BLACK FLIES IN THE SIMULIUM VENUSTUM AND VERECUNDUM SPECIES COMPLEXES (DIPTERA: SIMULIIDAE)

1982 ◽  
Vol 114 (6) ◽  
pp. 503-507 ◽  
Author(s):  
T. P. Snyder
Keyword(s):  
Lactate Dehydrogenase ◽  
Sibling Species ◽  
Black Flies ◽  
Genetic Affinity ◽  
Species Complexes ◽  
Species Pairs

AbstractElectrophoretic characterizations of sibling species in the Simulium venustum–verecundum complexes are presented based on nine enzymatic loci. Simulium verecundum s.l. is easily separable from S. venustum s.l. by unique complements of electromorphs for lactate dehydrogenase. Quantitative and minor qualitative differences also exist between most pairs of sibling species within S. venustum and S. verecundum. Not all pairs are separable using the nine enzymatic loci scored in this study. This close genetic affinity of species pairs that are not separable by electrophoretic methods parallels their chromosomal and ecological affinity.

THE SALIVARY GLAND CHROMOSOMES OF SEVEN FORMS OF BLACK FLIES INCLUDED IN EUSIMULIUM AUREUM FRIES

1959 ◽  
Vol 37 (4) ◽  
pp. 495-525 ◽  
Author(s):  
Robert W. Dunbar
Keyword(s):  
Salivary Gland ◽  
Sibling Species ◽  
Distinct Species ◽  
Black Flies ◽  
Black Fly ◽  
Species Pairs ◽  
Polymorphic Species

Seven closely related cytological forms are known for the dichromosomic black fly E. "aureum". All these forms have extremely similar salivary gland chromosomes but they differ from each other by (1) the floating (intraspecific) rearrangements present, (2) the details of the sex-determining mechanisms, and (3) at least one homozygous (interspecific) inversion in the first chromosome. Six of these forms are accounted for as three sympatric sibling species pairs. Although certain allopatric forms may yet be identified as geographic variants of a polymorphic species, evidence is presented to show that all seven forms are biologically distinct species. Their phylogenetic interrelationships have been traced by means of the homozygous interspecific inversions.

scholarly journals Molecular forms of Anopheles subpictus and Anopheles sundaicus in the Indian subcontinent

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Ankita Sindhania ◽  
Manoj K. Das ◽  
Gunjan Sharma ◽  
Sinnathamby N. Surendran ◽  
B. R. Kaushal ◽  
...  
Keyword(s):  
Sibling Species ◽  
Molecular Form ◽  
Indian Subcontinent ◽  
Phylogenetic Analyses ◽  
Coastal Areas ◽  
Molecular Forms ◽  
Nominal Species ◽  
Anopheles Subpictus ◽  
Species Complexes ◽  
Molecular Phylogenetic

Abstract Background Anopheles subpictus and Anopheles sundaicus are closely related species, each comprising several sibling species. Ambiguities exist in the classification of these two nominal species and the specific status of members of these species complexes. Identifying fixed molecular forms and mapping their spatial distribution will help in resolving the taxonomic ambiguities and understanding their relative epidemiological significance. Methods DNA sequencing of Internal Transcribed Spacer-2 (ITS2), 28S-rDNA (D1-to-D3 domains) and cytochrome oxidase-II (COII) of morphologically identified specimens of two nominal species, An. subpictus sensu lato (s.l.) and An. sundaicus s.l., collected from the Indian subcontinent, was performed and subjected to genetic distance and molecular phylogenetic analyses. Results Molecular characterization of mosquitoes for rDNA revealed the presence of two molecular forms of An. sundaicus s.l. and three molecular forms of An. subpictus s.l. (provisionally designated as Form A, B and C) in the Indian subcontinent. Phylogenetic analyses revealed two distinct clades: (i) subpictus clade, with a single molecular form of An. subpictus (Form A) prevalent in mainland India and Sri Lanka, and (ii) sundaicus clade, comprising of members of Sundaicus Complex, two molecular forms of An. subpictus s.l. (Form B and C), prevalent in coastal areas or islands in Indian subcontinent, and molecular forms of An. subpictus s.l. reported from Thailand and Indonesia. Based on the number of float-ridges on eggs, all An. subpictus molecular Form B were classified as Species B whereas majority (80%) of the molecular Form A were classified as sibling species C. Fixed intragenomic sequence variation in ITS2 with the presence of two haplotypes was found in molecular Form A throughout its distribution. Conclusion A total of three molecular forms of An. subpictus s.l. and two molecular forms of An. sundaicus s.l. were recorded in the Indian subcontinent. Phylogenetically, two forms of An. subpictus s.l. (Form B and C) prevalent in coastal areas or islands in the Indian subcontinent and molecular forms reported from Southeast Asia are members of Sundaicus Complex. Molecular Form A of An. subpictus is distantly related to all other forms and deserve a distinct specific status.

scholarly journals Insect Life: The Hidden Ecology of Black Flies: Sibling Species and Ecological Scale

1997 ◽  
Vol 43 (3) ◽  
pp. 153-162 ◽  
Author(s):  
Peter H. Adler ◽  
John W. McCreadie
Keyword(s):  
Sibling Species ◽  
Black Flies ◽  
Ecological Scale

Speciation in black flies

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 500-509 ◽  
Author(s):  
Klaus Rothfels
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Sympatric Speciation ◽  
Chromosome Polymorphism ◽  
Black Flies ◽  
Closely Related Species ◽  
Black Fly ◽  
Progressive Development ◽  
Temporal Relationships ◽  
Species Pairs

In many Simuliidae, patterns of spatial and temporal relationships among the most closely related species are more readily interpreted in terms of sympatric speciation than of allopatric speciation. Specific examples are (i) the allotriploid taxa in Gymnopais and other genera, (ii) the black fly faunas of geologically recent islands (Tahiti), and (iii) species in Prosimulium onychodactylum, a prototype of a continental multisibling species complex. A model of sympatric speciation is presented based on coadaptation of polymorphic sex chromosomes in pairs reinforced by progressive development of assortative mating. This model predicts that (i) populations should frequently exhibit sex-chromosome polymorphism, (ii) these sex-chromosome polymorphisms, and autosomal ones, should in some cases display linkage or association disequilibria, (iii) species pairs or complexes should be incurred that differ only in sex chromosomes and that share extensive ancestral autosomal polymorphisms, and (iv) such species should differ in their biology and perhaps their present-day distribution. Recent publications and observations are in accordance, in general, with predictions from the model. Genetic control, e.g., of diapause, larval developmental timing, and niche preference or ethology, could substitute as a basis of incipient cleavage. The evidence for sympatric speciation is purely inferential, but this is equally true for the allopatric interpretation, and in black flies the circumstantial evidence for prevalence of sympatric speciation appears more compelling. This is not to deny the efficacy of allopatry and founder effect in the origin of some species complexes.Key words: sympatric speciation, black fly, evolution.

Ecological segregation of larval black flies (Diptera: Simuliidae) in northern Saskatchewan, Canada

1990 ◽  
Vol 68 (10) ◽  
pp. 2113-2122 ◽  
Author(s):  
Jan J. H. Ciborowski ◽  
Peter H. Adler
Keyword(s):  
Relative Abundance ◽  
Environmental Gradients ◽  
Small Region ◽  
Larval Habitat ◽  
Black Flies ◽  
Species Complexes ◽  
Habitat Differentiation ◽  
Stream Size ◽  
Chemical Attributes ◽  
Physical And Chemical

We contrasted degree of habitat differentiation of cytospecies groupings with morphotaxon groupings of black flies collected within a small region offering extensive, spatially continuous simuliid larval habitat. Relative abundance of larvae was correlated with 16 physical and chemical attributes of 20 sites on streams near Uranium City, Saskatchewan. Chromosomal and morphological analyses demonstrated the presence of 20 species distributed among 14 morphotaxa. Principal components analysis of physical and chemical measurements distinguished five statistically independent groups of variables that were related to (i) stream size, (ii) pH, conductivity, and turbidity, (iii) oxygen saturation and substrate particle size, (iv) proximity to lake outlets, and (v) current velocity. Cytospecies belonging to species complexes tended to reach maximum relative abundances at different points along environmental gradients related to stream size and proximity to lake outlets. Cluster analysis of similarity in relative abundance of cytospecies among the 20 sites delineated seven groups. Reanalysis of sites according to morphotaxon data produced six groups. There was only partial congruence between groupings of the two analyses. Cytotaxonomic group sites were each characterized by a distinctive combination of stream size and proximity to an outlet. In contrast, sites classified as having similar morphotaxa were not environmentally distinct from river sites characterized by different morphotaxon assemblages. Thus, simuliid cytospecies represent distinct ecological entities, each adapted to particular suites of environmental variables.

scholarly journals Two decades of DNA barcoding in the genus Usnea (Parmeliaceae): how useful and reliable is the ITS?

2020 ◽  
pp. 303-357
Author(s):  
Robert Lücking ◽  
Miko Nadel ◽  
Elena Araujo ◽  
Alice Gerlach
Keyword(s):  
North America ◽  
Gene Duplication ◽  
Dna Barcoding ◽  
Data Sampling ◽  
Protein Coding ◽  
Species Complexes ◽  
Accuracy And Precision ◽  
Geographic Coverage ◽  
Species Pairs ◽  
Voucher Specimens

We present an exhaustive analysis of the ITS barcoding marker in the genus Usnea s.lat., separated into Dolichousnea, Eumitria, and Usnea including the subgenus Neuropogon, analyzing 1,751 accessions. We found only a few low-quality accessions, whereas information on voucher specimens and accuracy and precision of identifications was of subpar quality for many accessions. We provide an updated voucher table, alignment and phylogenetic tree to facilitate DNA barcoding of Usnea, either locally or through curated databases such as UNITE. Taxonomic and geographic coverage was moderate: while Dolichousnea and subgenus Neuropogon were well-represented among ITS data, sampling for Eumitria and Usnea s.str. was sparse and biased towards certain lineages and geographic regions, such as Antarctica, Europe, and South America. North America, Africa, Asia and Oceania were undersampled. A peculiar situation arose with New Zealand, represented by a large amount of ITS accessions from across both major islands, but most of them left unidentified. The species pair Usnea antarctica vs. U. aurantiacoatra was the most sampled clade, including numerous ITS accessions from taxonomic and ecological studies. However, published analyses of highly resolved microsatellite and RADseq markers showed that ITS was not able to properly resolve the two species present in this complex. While lack of resolution appears to be an issue with ITS in recently evolving species complexes, we did not find evidence for gene duplication (paralogs) or hybridization for this marker. Comparison with other markers demonstrated that particularly IGS and RPB1 are useful to complement ITS-based phylogenies. Both IGS and RPB1 provided better backbone resolution and support than ITS; while IGS also showed better resolution and support at species level, RPB1 was less resolved and delineated for larger species complexes. The nuLSU was of limited use, providing neither resolution nor backbone support. The other three commonly employed protein-coding markers, TUB2, RPB2, and MCM7, showed variable evidence of possible gene duplication and paralog formation, particularly in the MCM7, and these markers should be used with care, especially in multimarker coalescence approaches. A substantial challenge was provided by difficult morphospecies that did not form coherent clades with ITS or other markers, suggesting various levels of cryptic speciation, the most notorious example being the U. cornuta complex. In these cases, the available data suggest that multimarker approaches using ITS, IGS and RPB1 help to assess distinct lineages. Overall, ITS was found to be a good first approximation to assess species delimitation and recognition in Usnea s.lat., as long as the data are carefully analyzed, and reference sequences are critically assessed and not taken at face value. In difficult groups, we recommend IGS as a secondary barcode marker, with the option to employ more resource-intensive approaches, such as RADseq, in species complexes involving so-called species pairs or other cases of disparate morphology not reflected in the ITS or IGS. Attempts should be made to close taxonomic and geographic gaps especially for the latter two markers, in particular in Eumitria and Usnea s.str. and in the highly diverse areas of North America and Central America, Africa, Asia, and Oceania.

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