Intralacustrine site fidelity and nonrandom mating in the littoral-spawning northern redbelly dace (Phoxinus eos)

2008 ◽  
Vol 65 (9) ◽  
pp. 2016-2025 ◽  
Author(s):  
Rachel Massicotte ◽  
Pierre Magnan ◽  
Bernard Angers
Keyword(s):  
Site Fidelity ◽  
Isolation By Distance ◽  
Reproductive Period ◽  
Nonrandom Mating ◽  
Factors Affecting ◽  
Hardy Weinberg Equilibrium ◽  
Allelic Differentiation ◽  
Evolutionary Perspectives ◽  
Uniform Population ◽  
Spawning Sites

Natal site fidelity of the northern redbelly dace ( Phoxinus eos ), a common minnow in North America, was confirmed by combining ecological and genetic approaches. A 2-year mark–recapture experiment conducted at four sites separated by 50–450 m strongly supported the propensity of the dace to practice site fidelity during the reproductive period. Individuals recaptured at their marking sites were characterized with five microsatellite loci. Hardy–Weinberg equilibrium and allelic differentiation tests revealed that the fish from different sites significantly differed from a single panmictic and genetically uniform population, thus confirming the homing behaviour of the dace. The detection of a pattern of isolation by distance revealed that migration mostly occurred between nearby sites and decreased as distance from birth site increased. When considering the high population density of dace, their high swimming capability, the distribution of the spawning sites along the littoral zone, and the small size of the lake studied (<5 ha), these results strongly suggest natal site fidelity in this species. The detection of this phenomenon for this species is extremely useful for empirical investigations of factors affecting patterns of isolation by distance and of evolutionary perspectives of natal site fidelity in fishes.

scholarly journals Factors affecting menopause in Nepalese women

2017 ◽  
Vol 4 (2) ◽  
pp. 33-38
Author(s):  
Puja Paudel ◽  
Shital Bhandary ◽  
Jayandra Byanju
Keyword(s):  
Multivariate Analysis ◽  
Marital Status ◽  
Oral Contraceptives ◽  
Age Of Onset ◽  
Wealth Index ◽  
Reproductive Period ◽  
Bivariate Analysis ◽  
Health Issues ◽  
Factors Affecting ◽  
Independent Association

Introductions: Menopause is a physiological event that indicates the end of reproductive period in woman’s life. It has many health issues and morbidity. There are multiple factors that influence age of onset of menopause and we aim to find these associated factors. Methods: The 2011 ‘Nepal demographic and health survey’ data was used in this study. Logistic regression was used to find the association between the dependent and independent variables using bi-variate and multi-variate analysis. Results: The bivariate analysis showed the association of age, wealth index, education, marital status, employment, use of oral contraceptives and smoking with menopause. The multivariate analysis showed the independent association of age, education, employment and oral contraceptives. Conclusions: The employment, marital status and use of oral contraceptives were found to be independently associated with the age of onset of menopause on multivariate analysis.  

Genetic polymorphism in Proteocephalus exiguus shown by enzyme electrophoresis

1996 ◽  
Vol 70 (4) ◽  
pp. 345-349 ◽  
Author(s):  
V. Šnábel ◽  
V. Hanzelová ◽  
S. Mattiucci ◽  
S. D'Amelio ◽  
L. Paggi
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Polymorphism ◽  
Genetic Variability ◽  
Balancing Selection ◽  
Outcrossing Rate ◽  
Enzyme Electrophoresis ◽  
Factors Affecting ◽  
Hardy Weinberg Equilibrium ◽  
Coregonid Fishes

AbstractEnzyme electrophoresis has been used to examine genetic diversity in a population of Proteocephalus exiguus La Rue, 1911 (Cestoda: Proteocephalidae), parasitizing salmonid and coregonid fishes. Among 16 loci tested, three polymorphic loci (Ada, Got, Pgm-2) were found. Six different genotypes at the Got locus distributed in Hardy-Weinberg equilibrium suggest remarkable genetic flexibility of P. exiguus. Balancing selection is proposed as the mechanism maintaining genetic variation within the species. Data of genetic variability parameters (Ho = 0.064; He = 0.07; P = 0.19) and outcrossing rate (t = 0.842) of P. exiguus population have been provided. Possible factors affecting these data are discussed.

Breeding of the toad Bufo verrucosissimus: sexual dimorphism and shifting spawning sites

1994 ◽  
Vol 15 (2) ◽  
pp. 191-198 ◽  
Author(s):  
David N. Tarkhnishvili
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Site Fidelity ◽  
Inverse Correlation ◽  
Pair Formation ◽  
Mountain Forests ◽  
Reproductive Tactics ◽  
Breeding Sites ◽  
Toad Bufo ◽  
Spawning Sites

AbstractThe Colchic toad (Bufo verrucosissimus) inhabits wet mountain forests of Caucasia and breeds in small and unstable slow streams and seepage pools. Pair formation usually takes place on land. Amplexing couples search for new breeding sites every year; there is little site fidelity. Active searching for breeding sites is facilititated by the small size of males; the species is highly dimorphic, males having a mean body length of 70-85 mm, females a length of 100-130 mm. If a larger, more permanent water body appears in a region, reproductive tactics change and males wait for females around the pond. These generalizations are supported by data collected from 1989-1993. There was an inverse correlation between body size of females and males in amplexing pairs.

scholarly journals Developing Baltic cod recruitment models. II. Incorporation of environmental variability and species interaction

2001 ◽  
Vol 58 (8) ◽  
pp. 1534-1556 ◽  
Author(s):  
Friedrich W Köster ◽  
Hans-Harald Hinrichsen ◽  
Michael A St. John ◽  
Dietrich Schnack ◽  
Brian R MacKenzie ◽  
...  
Keyword(s):  
Egg Production ◽  
Gadus Morhua ◽  
Environmental Variability ◽  
Species Interaction ◽  
Larval Transport ◽  
Factors Affecting ◽  
Oxygen Conditions ◽  
Modelling Studies ◽  
Spawning Sites ◽  
Baltic Cod

We investigate whether a process-oriented approach based on the results of field, laboratory, and modelling studies can be used to develop a stock–environment–recruitment model for Central Baltic cod (Gadus morhua). Based on exploratory statistical analysis, significant variables influencing survival of early life stages and varying systematically among spawning sites were incorporated into stock–recruitment models, first for major cod spawning sites and then combined for the entire Central Baltic. Variables identified included potential egg production by the spawning stock, abiotic conditions affecting survival of eggs, predation by clupeids on eggs, larval transport, and cannibalism. Results showed that recruitment in the most important spawning area, the Bornholm Basin, during 1976–1995 was related to egg production; however, other factors affecting survival of the eggs (oxygen conditions, predation) were also significant and when incorporated explained 69% of the variation in 0-group recruitment. In other spawning areas, variable hydrographic conditions did not allow for regular successful egg development. Hence, relatively simple models proved sufficient to predict recruitment of 0-group cod in these areas, suggesting that key biotic and abiotic processes can be successfully incorporated into recruitment models.

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
Null Hypothesis ◽  
Isolation By Distance ◽  
Marine Species ◽  
Genetic Distances ◽  
Population Subdivision ◽  
Northwestern Pacific ◽  
Fisheries Conservation ◽  
Hardy Weinberg Equilibrium ◽  
Yalu River ◽  
Conservation And Management

<em>Abstract.—</em>Polymorphic microsatellite loci as genetic markers were used to reject the null hypothesis of panmixia for the Japanese eel, <em>Anguilla japonica</em>. Observed heterozygosity showed slight heterozygote deficiencies over all loci. One of the eight loci (MS-4) in one sample showed departure from Hardy-Weinberg equilibrium. Unbiased Nei’s genetic distances ranged from approximately 0.058 to 0.134. A slight genetic differentiation was determined by <EM>F</EM><sub>ST</sub> and <EM>R</EM><sub>ST</sub> statistics when adjusted with Bonferroni correction. Although isolation by distance is often observed in marine species, its use as a null hypothesis seems questionable. Although the freshwater eel is categorized as a catadromous fish, the value of genetic diversity obtained fell within that of marine fishes. A higher correlation (<EM>P </EM>< 0.001) resulting from AMOVA supports the separation of Japanese eels into two management units: a low-latitude group (Shantou, Tanshui, and Fangliao) and a high-latitude group (Daecheon-myon, Yalu River, Hangzhou, and Mikawa Bay). Such a population subdivision will be useful for further applications of fisheries conservation and management in the northwestern Pacific Ocean.

Long-term winter-site fidelity in Song Sparrows (Melospiza melodia)

The Auk ◽  
2019 ◽  
Vol 136 (2) ◽  
Author(s):  
Tosha R Kelly ◽  
Keith A Hobson ◽  
Garth W Casbourn ◽  
Elizabeth A MacDougall-Shackleton ◽  
Scott A MacDougall-Shackleton
Keyword(s):  
Population Dynamics ◽  
Site Fidelity ◽  
Migratory Birds ◽  
Melospiza Melodia ◽  
Factors Affecting ◽  
Song Sparrows ◽  
Breeding Grounds ◽  
Wintering Areas ◽  
Migratory Movements

Abstract In migratory animals, the degree to which individuals return to the same wintering sites across multiple years can affect fitness and population dynamics, and thus has important implications for conservation. Despite this, long-term evaluations of wintering-site fidelity are rare for migratory birds: many populations are intensively studied on their breeding grounds but tracking the migratory movements of small birds once they leave the breeding grounds is challenging. To evaluate patterns of overwintering location and fidelity, we collected winter-grown claw tissue from 301 Song Sparrows (Melospiza melodia; 449 samples) captured in spring at their breeding grounds over 6 consecutive yr and assessed stable hydrogen isotope (δ2Hc) values to determine within-individual repeatability and between-year variation in wintering latitudes. We also retrieved useable data from 8 geolocators over 2 consecutive winters. Geolocator-derived wintering positions correlated with origins based on δ2Hc values. Consistent with previous findings, male δ2Hc values reflected more northerly wintering areas than those of females, indicating shorter latitudinal migration distances for males, but the magnitude of the sex difference varied across years. The distribution of wintering latitudes was generally consistent among years, except for the 2015 舑2016 winter, which had unusually negative δ2Hc values. Values of δ2Hc were repeatable for males but not for females, suggesting that winter-site fidelity could differ between sexes. The data presented here emphasize the importance of tracking migratory populations across multiple years to uncover factors affecting population dynamics.

Analysis of genetic diversity in an invasive population of Asian long-horned beetles in Ontario, Canada

2009 ◽  
Vol 141 (6) ◽  
pp. 582-594 ◽  
Author(s):  
Maureen E. Carter ◽  
Michael T. Smith ◽  
Jean J. Turgeon ◽  
Richard G. Harrison
Keyword(s):  
Genetic Diversity ◽  
New York ◽  
New York City ◽  
York City ◽  
Haplotype Diversity ◽  
Population Based ◽  
Nonrandom Mating ◽  
Founding Population ◽  
Hardy Weinberg Equilibrium ◽  
Horned Beetles

AbstractAdult Asian long-horned beetles, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae: Lamiinae), were discovered in Ontario, Canada, in 2003 in the vicinity of a commercial warehouse. Trees were heavily scarred with signs of attack and larvae and adult beetles were common, suggesting that there had been multiple generations at the site. We amplified 16 microsatellite loci from 326 beetles to examine genetic diversity in this population. Based on Hardy – Weinberg equilibrium, 6 of 16 loci were monomorphic and 8 were not, indicating nonrandom mating. Measures of microsatellite genetic diversity and mitochondrial DNA haplotype diversity were significantly lower than those in A. glabripennis from China and Korea but were not significantly different from those in the New York City population. The proportion of different multilocus genotypes in the Ontario population was lower than in the populations in New York City and Linden, New Jersey. These results suggest that limited genetic diversity in the Ontario population has not hampered reproduction of this invasive insect. This genetic signature is common in other invasive species, likely because a population is founded by a few closely related individuals, or a large founding population suffers subsequent genetic bottlenecks.

scholarly journals Genetic Diversity and Population Structure of a Threatened African Tree Species,Milicia excelsa,Using Nuclear Microsatellites DNA Markers

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Christine Ouinsavi ◽  
Nestor Sokpon ◽  
Damase P. Khasa
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Isolation By Distance ◽  
In Situ Conservation ◽  
Agroforestry Systems ◽  
Microsatellites Dna ◽  
Geographical Distances ◽  
Hardy Weinberg Equilibrium ◽  
Milicia Excelsa

To accurately estimate the genetic diversity and population structure for improved conservation planning ofMilicia excelsatree, 212 individuals from twelve population samples covering the species' range in Benin were surveyed at seven specific microsatellite DNA loci. All loci were variable, with the mean number of alleles per locus ranging from 5.86 to 7.69. Considerable genetic variability was detected for all populations at the seven loci (AR=4.60;HE=0.811). Moderate but statistically significant genetic differentiation was found among populations considering bothFST(0.112) andRST(0.342). All of the populations showed heterozygosity deficits in test of Hardy-Weinberg Equilibrium and significantly positiveFISvalues due to inbreeding occurring in the species. PairwiseFSTvalues were positively and significantly correlated with geographical distances (r=0.432;P=.007, Mantel's test) indicating that populations are differentiated by “isolation by distance.” Bayesian analysis of population structure showed division of the genetic variation into four clusters revealing the existence of heterogeneity in population genetic structure. Altogether, these results indicate that genetic variation inMilicia excelsais geographically structured. Information gained from this study also emphasized the need for in situ conservation of the relict populations and establishment of gene flow corridors through agroforestry systems for interconnecting these remnant populations.

scholarly journals Variation in the structure of the ichthyoplankton community in the lower Paraíba do Sul River

2019 ◽  
Vol 17 (4) ◽  
Author(s):  
Gabriel E. Teixeira ◽  
Andréa Bialetzki ◽  
Bruno E. Soares ◽  
Guilherme Souza ◽  
Érica P. Caramaschi
Keyword(s):  
Fish Larvae ◽  
Reproductive Period ◽  
Main Channel ◽  
Severe Drought ◽  
Important Approach ◽  
Abundance And Distribution ◽  
Distribution Of Fish ◽  
Paraíba Do Sul River ◽  
Spawning Sites ◽  
River Fish

ABSTRACT The Paraíba do Sul River is affected by extensive water collection for supply, organic and industrial pollution, and dams. Nonetheless, the ichthyofauna maintains biodiversity and sustains artisanal fisheries. This study analyzes the composition, abundance and distribution of fish larvae, an important approach to determine the reproductive period and spawning sites. The sampling occurred from August 2011 through February 2013 in five sites at a transect between the banks on the lower reach of the Paraíba do Sul River. A total of 5,412 larvae belonging to 20 taxa was captured. The predominant order was Characiformes. Larvae of Prochilodus spp. and Leporinus spp. were the most abundant; larvae of Brycon insignis, an endangered species, were present. Fewer larvae were collected in the second reproductive cycle during a severe drought. The absence of eggs indicates that the study area is not used for spawning, and highlights the need for studies in the main channel and in the tributaries of the Paraíba do Sul River. Fish larvae need to have access to the marginal lagoons along the lower stretch of the river, an area which is the object of disputes between fishermen and farmers.

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