TRIPLOIDY IN NATURAL POPULATIONS OF THE BLACK FLY CNEPHIA MUTATA (MALLOCH)

Populations of Cnephia mutata in southern Ontario contain both diploid and triploid individuals. The diploid form is bisexual and lacks chromosomal polymorphism except for a rearrangement involved in its cytological sex determining mechanism. The triploids are parthenogenetic; they produce female progeny only and are highly heterozygous for inversions. The banding pattern of the salivary gland chromosomes of diploids and triploids is very similar; the identical standard sequence occurs in both. The complete lack of autosomal inversions in diploids contrasted with their abundance in triploids indicates that effective genetic exchange does not occur between the two forms; they are reproductively completely isolated, although opportunity for cross-mating would seem to exist. The origin of polyploid parthenogenetic forms in black flies is discussed and the view is favored that they are autopolyploid and automictic.

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THE SALIVARY GLAND CHROMOSOMES OF TWO SIBLING SPECIES OF BLACK FLIES INCLUDED IN EUSIMULIUM AUREUM FRIES

Canadian Journal of Zoology ◽

10.1139/z58-004 ◽

1958 ◽

Vol 36 (1) ◽

pp. 23-44 ◽

Cited By ~ 15

Author(s):

Robert W. Dunbar

Keyword(s):

New York ◽

Salivary Gland ◽

Sibling Species ◽

New York State ◽

Chromosomal Polymorphism ◽

Distinct Species ◽

Black Flies ◽

Southern Ontario ◽

York State ◽

Wide Range

Two closely related dichromosomic sibling species of Eusimulium "aureum" were segregated cytologically in populations sampled from the Toronto area. The known range of these two so far included southern Ontario and Quebec, and New York State. Both siblings have extremely similar salivary gland chromosomes but they differ by four homozygously rearranged regions, all in the first chromosome, and in the degree of chromosomal polymorphism. Although sympatric over a wide range, the two siblings do not interbreed as evidenced by the failure to find critical heterozygous loops for the interspecific inversions, and the absence of common intraspecific inversions. Therefore the siblings represent two biologically distinct species.

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Three New Ontario Black Flies of the Genus Prosimulium (Diptera: Simuliidae): Part I. Descriptions, Morphological Comparisons with Related Species, and Distribution

The Canadian Entomologist ◽

10.4039/ent90697-12 ◽

1958 ◽

Vol 90 (12) ◽

pp. 697-719 ◽

Cited By ~ 15

Author(s):

P. D. Syme ◽

D. M. Davies

Keyword(s):

Salivary Gland ◽

Banding Pattern ◽

Related Species ◽

External Environment ◽

Black Flies ◽

Eastern Canada ◽

Phylogenetic Relations ◽

Morphological Detail

Chromosonial studies have elucidated phylogenetic relations in Drosophila (White, 1954), culicids (Jucci, 1952) and chironomids (Bauer, 1936, 1945). Since it appeared promising to apply this approach to the Simuliidae, Rothfels and Dunbar (1953) began a cytological survey of the black flies of eastern Canada during the summer of 1951. They found that in this group the giant salivary gland chromosomes provided “a wealth of descriptive morphological detail in their number and gross morphology, in the characteristics of expanded centromere regions, in the location of specific nucleolar sites, in the degree of pairing of constituents, and in the ultimate discernible banding pattern…. Since these features are not functionally related to the external environment, the confusing effects of convergence are minimized, resemblances may be taken to indicate relation, and grouping is possible according to natural affinities” (Rothfels and Dunbar, 1953).

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GEOGRAPHIC VARIATION OF THE CHROMOSOMAL POLYMORPHISM IN DROSOPHILA FLAVOPILOSA

Canadian Journal of Genetics and Cytology ◽

10.1139/g76-016 ◽

1976 ◽

Vol 18 (1) ◽

pp. 111-118 ◽

Cited By ~ 2

Author(s):

Danko Brncic

Keyword(s):

Salivary Gland ◽

Polytene Chromosomes ◽

Natural Populations ◽

Chromosomal Polymorphism ◽

Weather Conditions ◽

Chromosomal Variation ◽

Seasonal Fluctuations ◽

Marginal Populations ◽

Geographic Variations ◽

Paracentric Inversions

Natural populations of the Chilean species Drosophila flavopilosa Frey are polymorphic for the banding sequences in the fifth chromosome due to the existence of four paracentric inversions. Qualitative analysis of the polymorphism demonstrated that there are seasonal fluctuations and geographic variations of two kinds: altitudinal gradients and a north-south gradient. In addition, the northernmost and southernmost samples examined are polymorphic only for one inversion (inversion "B"). In the light of previous experimental evidence, it was concluded that the seasonal fluctuations and elevational differences are probably controlled by weather conditions, especially temperature. However, the observed differences between the central and marginal populations require another type of interpretation, similar to that postulated for other species that exhibit the same pattern of chromosomal variation. A photomicrographic map of the Standard banding pattern of the salivary gland polytene chromosomes of D. flavopilosa is presented.

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

Canadian Journal of Zoology ◽

10.1139/z59-058 ◽

1959 ◽

Vol 37 (4) ◽

pp. 495-525 ◽

Cited By ~ 35

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.

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Reproduction in Trypanosomatids: Past and Present

Biology ◽

10.3390/biology10060471 ◽

2021 ◽

Vol 10 (6) ◽

pp. 471

Author(s):

Camino Gutiérrez-Corbo ◽

Bárbara Domínguez-Asenjo ◽

María Martínez-Valladares ◽

Yolanda Pérez-Pertejo ◽

Carlos García-Estrada ◽

...

Keyword(s):

Low Income ◽

Phenotypic Diversity ◽

Natural Populations ◽

Genetic Exchange ◽

Health Concern ◽

Current Debate ◽

Naturally Occurring ◽

Experimental Works ◽

Genomic Recombination ◽

The Impact

Diseases caused by trypanosomatids (Sleeping sickness, Chagas disease, and leishmaniasis) are a serious public health concern in low-income endemic countries. These diseases are produced by single-celled parasites with a diploid genome (although aneuploidy is frequent) organized in pairs of non-condensable chromosomes. To explain the way they reproduce through the analysis of natural populations, the theory of strict clonal propagation of these microorganisms was taken as a rule at the beginning of the studies, since it partially justified their genomic stability. However, numerous experimental works provide evidence of sexual reproduction, thus explaining certain naturally occurring events that link the number of meiosis per mitosis and the frequency of mating. Recent techniques have demonstrated genetic exchange between individuals of the same species under laboratory conditions, as well as the expression of meiosis specific genes. The current debate focuses on the frequency of genomic recombination events and its impact on the natural parasite population structure. This paper reviews the results and techniques used to demonstrate the existence of sex in trypanosomatids, the inheritance of kinetoplast DNA (maxi- and minicircles), the impact of genetic exchange in these parasites, and how it can contribute to the phenotypic diversity of natural populations.

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ECOLOGY OF BLACK FLIES (DIPTERA: SIMULIIDAE) OF THE SOURIS RIVER, MANITOBA AS A BASIS FOR CONTROL STRATEGY

The Canadian Entomologist ◽

10.4039/ent113223-3 ◽

1981 ◽

Vol 113 (3) ◽

pp. 223-234 ◽

Cited By ~ 6

Author(s):

A. R. Westwood ◽

R. A. Brust

Keyword(s):

Control Program ◽

Abundant Species ◽

Pest Species ◽

Black Flies ◽

Black Fly ◽

Simulium Vittatum ◽

Late Instar ◽

Simulium Decorum ◽

Fly Control ◽

Wire Cage

AbstractTen species of black flies were collected from the Souris River, Manitoba between April 1977 and October 1978. Adults of Simulium luggeri Nicholson and Mickel, Simulium meridionale Riley, Simulium venustum Say, Simulium verecundum Stone and Jamnback, and Simulium johannseni johannseni (Hart) were collected feeding on livestock and humans, and are well known pest species. Simulium vittatum Zetterstedt was the most abundant species, but was not a pest on man or domestic animals. Simulium tuberosum (Lundström) and Simulium johannseni duplex Shewell and Fredeen were the least abundant species. Simulium j. johannseni, S. j. duplex, S. venustum, S. verecundum, S. tuberosum, and Cnephia dacotensis (Dyar and Shannon) appeared to be univoltine species while S. luggeri, S. meridionale, Simulium decorum Walker, and S. vittatum were multivoltine in the Souris River.An evaluation of cone, plate, rope, and wire cage sampling devices for black fly larvae and pupae indicated that cone samplers provided a more representative sample for population assessment.In a black fly control program, of the Souris River, Manitoba two separate larvicide treatments in spring may be necessary. In the case of two treatments, the first should be aimed at late instar larvae of S. j. johannseni, S. venustum, and S. verecundum. Since the majority of S. luggeri and S. meridionale would be in the egg stage at this time, a second treatment, 10–14 days later, would be necessary to control late instar larvae of these species.

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Inversion polymorphism in some natural populations of Drosophila pseudoobscura from central Mexico

Genetika ◽

10.2298/gensr0703343s ◽

2007 ◽

Vol 39 (3) ◽

pp. 343-354 ◽

Cited By ~ 3

Author(s):

Víctor Salceda ◽

Judith Guzmán ◽

Olga Olvera

Keyword(s):

Relative Frequency ◽

Polytene Chromosomes ◽

Natural Populations ◽

Chromosomal Polymorphism ◽

Drosophila Pseudoobscura ◽

Central Mexico ◽

The Third ◽

Grand Total ◽

Different Populations ◽

Single Larva

Samples of D. pseudoobscura were taken in seventeen localities in Central Mexico inside the parallels 18o - 20o N, with the purpose of determine the chromosomal polymorphism in the third of the different populations of this species. From each captured female a single larva of its offspring was taken, its salivary glands extracted and stained with a solution of aceto orcein to observe the polytene chromosomes. From these smears the corresponding karyotype of each larva was determined, keeping a record of them. With the information gathered the relative frequency of each one of the fourteen different inversions found was calculated. A grand total of 1894 third chromosomes were analyzed. The fourteen different inversions found are equivalent to a 34.1 % of the total chromosomal variation of the species. The most abundant inversions found were: TL 50.6 %, CU 27.2 5, SC 9.1 % and EP 5.5 %; the remaining ten inversions detected are in general grounds rare ones with variable relative frequencies depending on the locality. Analysis of the predominant inversions for each population was done. The presence of West-East gradients is reported, even if in cases not so well defined, since as one moves in a particular direction the ups and downs in relative frequency for the alternating pairs TL-CU; TL-SC in the western populations and TL-CU in the eastern ones were observed. The assignment of each population to a particular race was also done, and such a way we were able to recognize three different races coexisting in the area of study.

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Evaluation of Partially Submerged Sticky Traps On Lake Spillways For Adult Black Fly (Diptera: Simuliidae) Surveillance and Arbovirus Detection

Journal of the American Mosquito Control Association ◽

10.2987/18-6792.1 ◽

2018 ◽

Vol 34 (4) ◽

pp. 306-310

Author(s):

Michael C. Cavallaro ◽

Eric Risley ◽

Paige Lockburner

Keyword(s):

Adult Female ◽

Rural Areas ◽

Surveillance Systems ◽

Black Flies ◽

Culex Mosquito ◽

Sticky Traps ◽

Black Fly ◽

Equine Encephalitis Virus ◽

Simulium Decorum ◽

Average Standard Error

ABSTRACT Sentinel surveillance systems demonstrate an improved ability to supplement monitoring data and anticipate arbovirus outbreaks (i.e., sentinel avian species). Management complications can arise during unpredictable or unseasonal disease detections, especially in rural areas where resident distribution is patchy. Using spillways near residential lake communities as static surveillance locations, we tested a novel partially submerged sticky trapping technique and screened wild populations of adult female black flies (Diptera: Simuliidae) for West Nile virus (WNV) and eastern equine encephalitis virus (EEEV). Trap site selection criteria considered the density of immature black fly colonization on spillway surfaces and the number of positive detections of arboviral targets in nearby Culex mosquito populations. On average (±standard error), sticky traps captured 134 (±33) adult black flies over a 24-h period, with 1 trap capturing as many as 735 individuals. Although we detected positive cases of WNV from 20 Culex mosquito trapping sites within 16 km (approx. flight radius) of the selected lake spillways, mixed pools of adult female Simulium vittatum complex and Simulium decorum were all negative for both arboviruses. This study yielded an application for partially submerged sticky traps to collect adult female black flies. Its potential uses for monitoring the infection rates of more well-documented Simulium parasites are discussed.

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Micro-geographic variation of inversions in natural populations of Drosophila pseudoobscura

Genetika ◽

10.2298/gensr0602097s ◽

2006 ◽

Vol 38 (2) ◽

pp. 97-105 ◽

Cited By ~ 3

Author(s):

Víctor Salceda ◽

José Espinoza-Velazquez

Keyword(s):

Geographic Variation ◽

Population Sample ◽

Polytene Chromosomes ◽

Natural Populations ◽

Chromosomal Polymorphism ◽

Drosophila Pseudoobscura ◽

Natural Habitats ◽

San Luis ◽

San Luis Potosi ◽

San Luis Potosí

Chromosomal polymorphism for the third chromosome in Drosophila pseudoobscura has been widely studied for genetic variation in different environments or locations far apart. However, there is less information regarding sites geographically near one another. Targeting on possible micro-geographic variation in the species, a serial study was done on 12 Mexican populations grouped in four regions, including locations in Durango (DU), the border area of Guanajuato-San Luis Potosi states (GP), Chiapas (CH) and Saldilo (SA). Flies were trapped in their natural habitats using fermenting bananas as bait. They were individually cultivated in the laboratory for larvae production. In a given population sample several flies were cultivated together but only one larva per culture provided salivary tissue to observe polytene chromosomes. Gene arrangements or inversions were identified and frequencies were calculated. A total of 767 third chromosomes were studied and 11 different inversions detected. The type and relative frequencies of the arrangements varied among regions. From the 11 inversions observed, 10 were found in Durango, five in Guanajuato-San Luis Potosi and Chiapas, and eight in Saltillo. The inversion frequencies in the Durango locations varied in four cases, but only one in Chiapas, three cases in Guanajuato-San Luis Potosi, and five in Saltillo. It was also observed that there were geographical gradients for inversions within regions as follows: four arrangements in Saltillo and Durango, three in Guanajuato-San Luis Potos? and one in Chiapas. Moreover, all four regions studied showed evidences for micro-geographical variation. Nevertheless, more studies are needed to elucidate the relevance of the inversion frequencies changes in neighboring populations and also any seasonal-annual frequencies observed in the locations studied here.

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