FECUNDITY OF MELANOPLUS SANGUINIPES (F.) IN TWO CRESTED WHEATGRASS PASTURES

1988 ◽  
Vol 120 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Norma E. Sanchez ◽  
Jerome A. Onsager ◽  
William P. Kemp
Keyword(s):  
Oviposition Rate ◽  
Melanoplus Sanguinipes ◽  
Natural Conditions ◽  
Crested Wheatgrass ◽  
Degree Day ◽  
Two Populations

AbstractOviposition rate (eggs per ♀-degree-day) and fecundity (total number of eggs per ♀) were measured in two populations of Melanoplus sanguinipes (F.) under natural conditions during two seasons (1984, 1985). Differences in fecundity between the two seasons were indirectly associated with differences in time of hatching. In 1985, females hatched earlier and had shorter preoviposition periods, greater longevities, and higher oviposition rates; consequently, fecundity averaged about three-fold greater than in 1984. Longevity appeared to be the most important single determinant of fecundity. Maximum fecundity was 73.2 eggs (equivalent to four pods) and mean fecundity ranged between 10.1 and 28.9 eggs per female.

LIFE HISTORY PARAMETERS IN MELANOPLUS SANGUINIPES (F.) IN TWO CRESTED WHEATGRASS PASTURES

1988 ◽  
Vol 120 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Norma E. Sanchez ◽  
Jerome A. Onsager
Keyword(s):  
Life History ◽  
Survival Rates ◽  
Adult Longevity ◽  
Melanoplus Sanguinipes ◽  
Crested Wheatgrass ◽  
Life History Parameters ◽  
Preoviposition Period ◽  
Point Estimates ◽  
Two Populations ◽  
Net Replacement

AbstractA combination of published techniques provided point estimates of life history parameters for two natural field populations of Melanoplus sanguinipes (F.) in crested wheatgrass pastures. Stage-specific survival rates averaged 0.4798, 0.2261, 0.7628, and 0.6903 for egg, instars I–III combined, instar IV, and instar V, respectively. Daily survival rates of adults averaged 0.9702, but were slightly lower for females than for males. Estimated duration of nymphal instars averaged 8.4 days, the adult preoviposition period averaged 13.3 days, and adult longevity averaged 26.7 and 36.3 days in the two populations. Oviposition rates were estimated for up to four successive ovipositions, and net replacement rates of populations also were estimated. Neither population replaced itself, indicating that potential capacities for increase were not approached under conditions of these studies.

Examining effects of persistent retroviral infection on fitness and pathogen susceptibility in a natural feline host

2006 ◽  
Vol 84 (3) ◽  
pp. 365-373 ◽  
Author(s):  
Roman Biek ◽  
Toni K Ruth ◽  
Kerry M Murphy ◽  
Charles R Anderson, Jr. ◽  
Mary Poss
Keyword(s):  
Puma Concolor ◽  
Stochastic Simulations ◽  
Nonsignificant Trend ◽  
Natural Conditions ◽  
Retroviral Infection ◽  
Animal Populations ◽  
Secondary Infections ◽  
In The Wild ◽  
Serological Data ◽  
Two Populations

Many animal populations carry endemic (i.e., permanently present) viruses but few studies have assessed the demographic consequences of these infections under natural conditions. We examined the effects of chronic infection with FIVPco, a feline retrovirus, on the fitness and pathogen susceptibility of its natural host, the cougar (Puma concolor (L., 1771)), in the wild. Based on data obtained through intensive monitoring of 160 cougars from two populations, we estimated survival and different measures of host fecundity of infected and uninfected individuals. In addition, we used serological data collected from 207 cougars to test whether FIVPcopredisposes individuals to a higher probability of infection with other pathogens. We found no evidence for an overall reduction in survival due to FIVPcowhen accounting for other sources of demographic variation (age, sex, and population). There was a consistent but nonsignificant trend towards poorer reproductive performance in FIVPco-infected females. We found no serological evidence for a higher probability of secondary infections associated with FIVPco. Overall, these results support the premise that chronic FIVPcoinfection is asymptomatic in its natural cougar host, probably because of a long evolutionary association between virus and host. However, results of stochastic simulations indicate that only larger reductions in annual survival (>20%) can be excluded with confidence. Also, the possibility of a so far unrecognized cost of FIVPcoinfection on cougar fecundity remains.

scholarly journals About Some Features of the Ability of Flowering Specials Crocus reticulatus in Various Elements of the Mesorelief of Beams in the Southern of the Middle Russian Hill

2020 ◽  
Vol 2 (2) ◽  
pp. 147-163
Author(s):  
V.I. Cherniavskih ◽  
◽  
T.N. Glubscheva ◽  
◽  
Keyword(s):  
Point Of View ◽  
Variance Analysis ◽  
Natural Conditions ◽  
Economic Point ◽  
Factor B ◽  
Slope Factor ◽  
The One ◽  
Number Of Individuals ◽  
Two Populations ◽  
Productive Trait

The article presents the results of a three-year study of two populations of Crocus reticulatus, in the conditions of the beams of the Veidelevsky district of the Belgorod region. We studied the abundance of flowering individuals (potentially reproductive abundance) of C. reticulatus in two model populations and their distribution in different elements of the beam mesorelief along the gradient: the upper part of the slope – the base of the slope – the bottom of the beam. Comprehensive stationary monitoring studies were carried out in 2018-2020. in key areas in accordance with the program and methodology of biogeocenotic studies by the method of randomized repetition with the allocation of organized factors: Factor A – «habitat» and Factor B – «gradient of the slope». The results of the variance analysis of the one-factor complex in some years showed that the influence of the «gradient of the slope» factor on the productive trait «the abundance of flowering individuals» in key plot N 1 ranged from 98.4 % in 2020 to 99.6 % in 2018, in the key plot N 2 - from 98.5 % in 2019 to 99.5 % in 2020. On average, over 3 years of research in key area No. 1, an abundance of 336.2 ind./100 m2 was observed at Cv = 179.6 % in the gradient of the slope. An abundance of 237.4 ind./100 m2 at Cv = 101.1 % along the gradient of the slope was noted at key area N 2. The maximum number of flowering individuals was noted in the narrow ecotone part of the transition of the slope to the bottom of the beam (transects I): in plot N 1 – 1,890 ind./100 m2, and in plot No 2 – 856.7 ind./100 m2. An analysis of the share of the influence of organized factors by the method of variance analysis of two-factor complexes on average for 2018-2019 showed that the factor B, “gradient of the slope”, h2x = 79.5 %, exerted the greatest influence on the resultant trait “abundance of flowering individuals”. The factor “habitat of the population” and the interaction of factors had a significantly smaller effect on the number of individuals – 1.2 and 17.0 %, respectively. It is concluded that the study of the potentially reproductive abundance of C. reticulatus in natural conditions can contribute to the process of creating narrow-local artificial populations with a number of specific features, including those useful from an economic point of view for introduction into culture and breeding.

Comparison of Principal Component Solutions in Two Populations

Methodology ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Gregor Sočan
Keyword(s):  
Simulation Study ◽  
Principal Components ◽  
Common Factor ◽  
Principal Component ◽  
Component Model ◽  
Bootstrap Procedure ◽  
Factor Loadings ◽  
Component Loadings ◽  
Principal Component Model ◽  
Two Populations

Abstract. When principal component solutions are compared across two groups, a question arises whether the extracted components have the same interpretation in both populations. The problem can be approached by testing null hypotheses stating that the congruence coefficients between pairs of vectors of component loadings are equal to 1. Chan, Leung, Chan, Ho, and Yung (1999) proposed a bootstrap procedure for testing the hypothesis of perfect congruence between vectors of common factor loadings. We demonstrate that the procedure by Chan et al. is both theoretically and empirically inadequate for the application on principal components. We propose a modification of their procedure, which constructs the resampling space according to the characteristics of the principal component model. The results of a simulation study show satisfactory empirical properties of the modified procedure.

Molecular phylogeny and taxonomic evaluation of the genus Asaccus Dixon and Anderson, 1973 (Reptilia: Phyllodactylidae) in Iran

2020 ◽  
pp. 207-214
Author(s):  
Akbar Fattahi
Keyword(s):  
Molecular Phylogeny ◽  
Nuclear Gene ◽  
Genetic Distances ◽  
Genetic Lineage ◽  
New Taxon ◽  
Zagros Mountains ◽  
Relict Species ◽  
Taxonomical Revision ◽  
Two Populations ◽  
Taxonomic Evaluation

The Iranian species of the phyllodactylid geckos of the genus Asaccus are found only in the valleys of the Zagros Mountains, a region which represents an important area of endemism in western Iran. Recently, many relict species have been described from the central and southern parts of the Zagros Mountains, which were previously known as A. elisae. The recent descriptions of species within this complex suggest that diversity within the genus may be higher than expected and that its taxonomy and systematics should be revised. In the present study, phylogenetic relationships within the genus Asaccus were evaluated using two mitochondrial and one nuclear gene. Genetically, the genus shows high levels of variability. The molecular phylogeny of the genus suggests the presence of three main clades along the Zagros Mountains with the southern population (from the Hormozgan province) and one clade (A. sp8 and A. sp9) being sister taxon to A. montanus from UAE. The remaining samples are separated into two reciprocally monophyletic groups: the northern (Kurdistan, Kermanshah and Ilam provinces) and the central (Lorestan, Khuzestan, Kohgilouye-Bouyer Ahmad and Fars provinces) Zagros groups. The results of the present study suggest that populations attributed to A. elisae in Iran correspond to distinct lineages with high genetic distances. In brief, our results suggest that the genus needs a major taxonomical revision The Arabian origin of the genus has not been confirmed, because two populations from Zagros were located within the A. montanus, A. gallagheri and A. platyrhynchus clade. Further morphological analyses are needed to systematically define each genetic lineage as a new taxon.

Thierry Kuntzel and the Rise of Video Art

2018 ◽  
Author(s):  
Hilary Radner ◽  
Alistair Fox
Keyword(s):  
New Technology ◽  
Video Art ◽  
Video Technology ◽  
Natural Conditions

Raymond Bellour describes how his interest in video art grew out of his personal friendship with Thierry Kuntzel and the latter’s growing interest in experimental filmmaking using the new technology, and how this interest prompted him to seek to understand how the new medium was leading to a modification of perception. He goes on to explain how video technology enables the production of images that escape the natural conditions deemed to constrain photography, also emphasizing the influence of painting on video art.

Comparing Genetic Variation within Red Winter Wheat Populations with and without Image-Based Optical Sorter Selection

2019 ◽  
Vol 9 (2) ◽  
pp. 266-277
Author(s):  
Hussein M. Khaeim ◽  
Anthony Clark ◽  
Tom Pearson ◽  
Dr. David Van Sanford
Keyword(s):  
Genetic Variation ◽  
Fusarium Head Blight ◽  
Heading Date ◽  
Fusarium Head Blight Resistance ◽  
Gibberella Zeae ◽  
Mass Selection ◽  
Head Blight ◽  
Red Winter Wheat ◽  
Two Populations ◽  
Head Scab

Head scab is historically a devastating disease affecting not just all classes of wheat but also barley and other small grains around the world. Fusarium head blight (FHB), or head scab, is caused most often by Fusarium graminearum (Schwabe), (sexual stage – Gibberella zeae) although several Fusarium spp. can cause the disease. This study was conducted to determine the effect of mass selection for FHB resistance using an image-based optical sorter. lines were derived from the C0 and C2 of two populations to compare genetic variation within populations with and without sorter selection. Our overall hypothesis is that sorting grain results in improved Fusarium head blight resistance. Both of the used wheat derived line populations have genetic variation, and population 1 has more than population 17. They are significantly different from each other for fusarium damged kernel (FDK), deoxynivalenol (DON), and other FHB traits. Although both populations are suitable to be grown for bulks, population 1 seems better since it has more genetic variation as well as lower FDK and DON, and earlier heading date. Lines within each population were significantly different and some lines in each population had significantly lower FDK and DON after selection using an optical sorter. Some lines had significant reduction in both FDK and DON, and some others had either FDK or DON reduction. Lines of population 1 that had significant reduction, were more numerous than in population 17, and FDK and DON reduction were greater.

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