Younger bank voles are more vulnerable to avian predation

2008 ◽  
Vol 86 (9) ◽  
pp. 1074-1078 ◽  
Author(s):  
Taru Meri ◽  
Matti Halonen ◽  
Tapio Mappes ◽  
Jukka Suhonen
Keyword(s):  
Sex Ratio ◽  
Clethrionomys Glareolus ◽  
Selective Predation ◽  
Field Sample ◽  
Avian Predator ◽  
Avian Predation ◽  
Bank Voles ◽  
Significant Difference ◽  
Total Impact ◽  
Selection Of

The importance of predation on prey populations is mainly determined by the number of eaten prey. However, the total impact of predation might also be determined by the selection of certain prey individuals, e.g., different sexes or age categories. Here we tested selective predation by an avian predator, the pygmy owl ( Glaucidium passerinum (L., 1758)), on bank voles ( Myodes ( Clethrionomys ) glareolus (Schreber, 1780)). We compared the sex, age, and mass of hoarded prey with the animals snap-trapped from the field. There were no differences in the sex ratio between hoarded bank voles and those available in the field. However, hoarded voles were significantly younger than ones in the field sample. There was no statistically significant difference in mass between animals from larders and from the field. We suggest that the greater vulnerability of younger animals to predation might be due to their higher activity, or alternatively, they might be forced to forage in less safe habitats.

Consistency and change in bank vole (Clethrionomys glareolus) home ranges across a decade

1998 ◽  
Vol 76 (7) ◽  
pp. 1329-1334 ◽  
Author(s):  
A Fredric Karlsson ◽  
Eugene R Potapov
Keyword(s):  
Home Range ◽  
Snow Cover ◽  
Bank Vole ◽  
Snow Depth ◽  
Clethrionomys Glareolus ◽  
Home Ranges ◽  
Partial Explanation ◽  
Mating Period ◽  
Bank Voles ◽  
Significant Difference

Minimum distance moved (MDM) and home-range sizes were studied in overwintering bank voles (Clethrionomys glareolus) during March and April in 1985, 1986, and 1996 near Uppsala, Sweden. In 1985 and 1986, the average snow depth was 50 and 35 cm in March and 7 and 18 cm in April, respectively. In 1996 the snow depth was only 16 cm in March and 2 cm in April. Bank voles were found to have winter nests at exactly the same grid coordinates in 1985, 1986, and 1996. Among females there was a high degree of consistency in home-range sizes, both between months and between years. Daily MDM of females was shorter in March 1996 than in 1985 and 1986, while no significant difference occurred during April. Males' home-range sizes, on the other hand, increased significantly from March to April in all 3 years, i.e., at the onset of the mating period. There was no significant difference in males' home-range sizes in March across years, but in April, home ranges were significantly larger 1985 and 1986 than in 1996. Males' average home-range sizes in April showed a positive correlation with snow depth. MDM of males in both March and April was also significantly higher during the snowy years of 1985 and 1986 than in 1996, when there was much less snow. These observations suggest that adequate snow cover is a favourable factor, allowing the males to expand their home ranges, while lack of snow or a thin, patchy snow cover prevents them from travelling longer distances during the mating period and consequently from visiting a large number of potential mates. These differences in the behaviour of male bank voles between snow-rich and snow-poor years may offer a partial explanation of the hypothetical connection between the less severe winter conditions during the past decade and the decline in population density and cyclicity in boreal bank vole populations.

The ecology of the tick Ixodes trianguliceps Birula (Arachnida; Acarina; Ixodoidea)

Parasitology ◽  
1967 ◽  
Vol 57 (3) ◽  
pp. 525-531 ◽  
Author(s):  
M. J. Cotton ◽  
C. H. S. Watts
Keyword(s):  
Life History ◽  
Soviet Union ◽  
Seasonal Distribution ◽  
Clethrionomys Glareolus ◽  
Research Student ◽  
Small Peak ◽  
Bank Voles ◽  
The Soviet Union ◽  
Significant Difference ◽  
Ixodes Trianguliceps

The ecology of the tick Ixodes trianguliceps Bir. is described from material collected at two localities in Wytham Estate near Oxford. The hosts examined were bank voles, Clethrionomys glareolus Schr., field voles, Microtus agrestis (L.), and field mice, Apodemus sylvaticus (L.).The seasonal distribution of the tick is biannual, with spring and autumnal peaks as found in Ixodes ricinus (L.). Larvae occur throughout the year but principally in spring and autumn. Nymphs are found only from late spring until the autumn, and adults principally in the spring with a small peak in autumn.Larvae and nymphs of I. trianguliceps were more abundant on male than on female bank voles, but there was no significant difference in the infestation of males and females by adult ticks. Similarly there was no significant difference in the infestation of adult and juvenile bank voles.Larvae and nymphs occur principally on the ears, but the adult ticks are found mainly on the neck or body, although the ears were not excluded from infestation.The seasonal distribution and life-history is discussed with reference to similar studies made in the Soviet Union and in Poland. Male ticks were found in copula on the host, and both males and nymphs were collected from the nests of voles.A tentative summary of the life-history of I. trianguliceps is given based on known facts for the hedgehog tick, Ixodes hexagonus Leach, which has a similar seasonal occurrence.We wish to thank Professor Don Arthur for identification of much of the tick material, especially in the early stages of this study, and for useful criticism of the draft manuscript. The work was carried out while one of us (M.J.C.) was a research student in the Hope Department of Entomology, Oxford, and the other (C.H.S.W.) a research student at the Bureau of Animal Population, Oxford. For facilities in both departments we wish to express our gratitude.

Some data on the fertility of bank voles (Clethrionomys glareolus britannicus) in the laboratory supporting the hypothesis of induced ovulation

1984 ◽  
Vol 18 (1) ◽  
pp. 33-35 ◽  
Author(s):  
F. O. Ödberg
Keyword(s):  
Sex Ratio ◽  
Clethrionomys Glareolus ◽  
Induced Ovulation ◽  
Bank Voles

83 (40%) litters with an average of 3·42 pups and unbiased sex ratio were born of 207 couples. Fertility and litter average were higher in summer and autumn. Most females were fertilized on the 1st day spent with a male, which supports the mating-induced ovulation hypothesis. Infantile mortality was highest at birth and during the 1st 5 days of life. 26% of the pups died before weaning (day 25), i.e. an average of 1 per litter.

A Comparison of Four Adolescent Language Tests

1987 ◽  
Vol 18 (3) ◽  
pp. 250-266 ◽  
Author(s):  
R. Jane Lieberman ◽  
Ann Marie C. Heffron ◽  
Stephanie J. West ◽  
Edward C. Hutchinson ◽  
Thomas W. Swem
Keyword(s):  
Test Performance ◽  
Sixth Grade ◽  
Significant Discrepancy ◽  
Language Impaired ◽  
Language Functions ◽  
Language Tests ◽  
Significant Difference ◽  
Sixth Grade Students ◽  
Overall Performance ◽  
Selection Of

Four recently developed adolescent language tests, the Fullerton Test for Adolescents (FLTA), the Test of Adolescent Language (TOAL), the Clinical Evaluation of Language Functions (CELF), and the Screening Test of Adolescent Language (STAL), were compared to determine: (a) whether they measured the same language skills (content) in the same way (procedures); and (b) whether students performed similarly on each of the tests. First, respective manuals were reviewed to compare selection of subtest content areas and subtest procedures. Then, each of the tests was administered according to standardized procedures to 30 unselected sixth-grade students. Despite apparent differences in test content and procedures, there was no significant difference in students' performance on three of the four tests, and correlations among test performance were moderate to high. A comparison of the pass/fail rates for overall performance on the tests, however, revealed a significant discrepancy between the proportions of students identified in need of further evaluation on the STAL (20%) and the proportion diagnosed as language impaired on the three diagnostic tests (60-73%). Clinical implications are discussed.

Fecundity and Gonado-somatic Index of Trichiurus lepturus (Linnaeus, 1758) Along the Zamboanga del Norte Coast

2018 ◽  
Vol 6 (7) ◽  
pp. 120
Author(s):  
Ma. Dulce C. Guillena
Keyword(s):  
Sex Ratio ◽  
Stock Assessment ◽  
Chi Square ◽  
Moon Phases ◽  
Ovary Weight ◽  
Moment Coefficient ◽  
Trichiurus Lepturus ◽  
Significant Difference ◽  
The Relationship ◽  
Somatic Index

Gonado-somatic index and fecundity are tools for measuring the sexual maturity and ability of animals to reproduce.  This study investigates the reproduction of Trichiurus lepturus. Specifically, this aimed to determine the sex ratio, the GSI, the relationship between fecundity and total length, fecundity and total weight, fecundity and ovary weight. The Descriptive Method of research was used.  Percentage and chi-square was utilized in determining the percentage of occurrence and sex ratio respectively.   Pearson r Product Moment Coefficient of Correlation was used to determine the relationships of the parameters. The study revealed that females outnumbered males and the sex ratio for different month showed significant difference.  Spawning season was observed to occur in November and December as revealed in its GSI values and it synchronized with the full and new moon phases.  Fecundity is positively correlated with body weight, body size, and ovary weight where ovary weight is observed to be the best index for fecundity.  The results of this study could be used further for formal stock assessment of cutlassfish fishery.

Comparative study of Clinical Characteristics in Patients with Mild and Severe Reflux Esophagitis

2020 ◽  
Vol 66 (1) ◽  
pp. 19-22
Author(s):  
Melania Macarie ◽  
Simona Maria Bataga ◽  
Monica Pantea ◽  
Razvan Opaschi ◽  
Simona Mocan ◽  
...  
Keyword(s):  
Risk Factors ◽  
Sex Ratio ◽  
Hiatal Hernia ◽  
Statistical Significance ◽  
Erosive Esophagitis ◽  
Male Gender ◽  
Consecutive Series ◽  
Study Group ◽  
Entire Study ◽  
Significant Difference

AbstractObjective: This study aims to determine the correlation between risk factors and erosive esophagitis development.Methods: We conducted a retrospective observational study on a consecutive series of 19.672 patients who underwent upper gastrointestinal endoscopy between 01.01.2011-31.12.2017. A total of 3005 patients, diagnosed with erosive esophagitis, were included in the present study and stratified according to Los Angeles classification.Results: During the studied period we found 3005 patients with erosive esophagitis, sex ratio male to female was 1.3/1, the most common forms of esophagitis being grade A and B: 74.54% patients with esophagitis grade A, 14.80% patients with grade B; 5.29% patients were with grade C and 5.35% patients with esophagitis grade D. In severe esophagitis the male predominance was more prevalent (249 males, 71 female), with a sex ratio 3.50/1. The correlation of male gender with severe esophagitis was highly statistically significant (p < 0.0001, OR 2.97; 95% CI 2.25-3.91). Hiatal hernia was diagnosed in 1171 patients, the presence of large hiatal hernias, being an important predictor, with statistical significance (p < 0.0001, OR 3.41; 95% CI 2.22-5.21), for severe esophagitis development. Incidence of Helicobacter pylori infection was 11.51%, in the entire study group, with no statistical significant difference between patients with mild or severe esophagitis (12.02% vs 7.18%).Conclusion: Erosive esophagitis is a frequent disease, the most common forms being grade A and B. Male gender and the presence of hiatal hernia are the most important risk factors for erosive esophagitis development, in our study group.

Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Block Design ◽  
Coffea Canephora ◽  
Coffee Production ◽  
Randomized Block Design ◽  
Significant Difference ◽  
The Mean ◽  
Four Blocks ◽  
Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

Temperature Selection of Rainbow Trout (Salmo gairdneri) Fingerlings in Vertical and Horizontal Gradients

1971 ◽  
Vol 28 (11) ◽  
pp. 1801-1804 ◽  
Author(s):  
R. W. McCauley ◽  
W. L. Pond
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Temperature Preference ◽  
Temperature Selection ◽  
Horizontal Gradients ◽  
Significant Difference ◽  
Preferred Temperatures ◽  
Laboratory Investigations ◽  
Horizontal Temperature Gradients ◽  
Selection Of

Preferred temperatures of underyearling rainbow trout (Salmo gairdneri) were determined in both vertical and horizontal temperature gradients. No statistically significant difference was found between the preferred temperatures by the two different methods. This suggests that the nature of the gradient plays a lesser role than generally believed in laboratory investigations of temperature preference.

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