Population Dynamics of Sucking Pests in Guava Under High Density Planting

2021 ◽  
Vol 83 (2) ◽  
pp. 276-279
Author(s):  
C Prabakaran ◽  
M Suganthy ◽  
T Tamilnayagan ◽  
M Kavino
Keyword(s):  
Population Dynamics ◽  
High Density

scholarly journals The Effect of Conspecific Density on Emergence ofLestes bipupillatusCalvert, 1909 (Odonata: Lestidae)

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Ricardo Cardoso-Leite ◽  
Gabriel C. Vilardi ◽  
Rhainer Guillermo-Ferreira ◽  
Pitágoras C. Bispo
Keyword(s):  
Population Dynamics ◽  
Density Dependence ◽  
Social Environment ◽  
Growth Rates ◽  
High Density ◽  
Conspecific Density ◽  
Simulated Environments ◽  
The Social ◽  
Emergence Date

Conspecific density may influence adult recruitment and consequently population dynamics. Several studies have shown the density dependence of larvae growth rates in Odonata. However, few studies studied how conspecific density influence final instar larvae emergence date decisions. Considering that larvae may choose the date of emergence, the present study investigated if density affects larvae choice. For this, we reared eight final instar larvae in individual aquaria and other 24 larvae in aquaria with three larvae each. This way, we simulated environments with low and high larval densities. We then noted the days that larvae took to emerge and compared it between low and high density groups. The results showed that larvae seem to emerge earlier when in high densities (Mann-Whitney,U=10.000,P=0.03). These results support the hypothesis that damselfly last instar larvae may postpone or hasten emergence in response to the social environment and related constraints.

scholarly journals A 25-years population dynamics of sika deer in Kyushu Island, Japan: Estimation using vector autoregressive spatiotemporal model and evaluation of a large-scale management

2021 ◽  
Author(s):  
Kei Suzuki ◽  
Yasumitsu Kuwano ◽  
Yuki Kanamori ◽  
Yohei Kawauchi ◽  
Yoshihiko Uchimura ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Density Dependence ◽  
Large Scale ◽  
Sika Deer ◽  
High Density ◽  
Management Units ◽  
Vector Autoregressive ◽  
Kyushu Island ◽  
Core Areas ◽  
Scale Management

Regional management of large herbivore populations is known to be effective in reducing local economic damages and conserving local endemic plants. However, herbivores often move across management areas, and the effect of population management on a large spatial scale is poorly understood, even though it is necessary to use a large-scale approach across multiple management units to implement appropriate management. In this study, to better understand large-scale management and improve management efficiency, we evaluated effects of large-scale management of a sika deer (Cervus nippon) population on Kyushu Island (approximately 36,750 km2) in Japan. We estimated the population dynamics and spatial distributions of the deer and evaluated the effects of harvests, density dependence, and climatic conditions on the population dynamics both across Kyushu Island and in smaller prefectural management units. Fecal pellet count surveys conducted from 1995 to 2019 and results from a vector autoregressive spatio-temporal model showed relatively stable population dynamics and four high-density core areas. No increasing or decreasing trends were observed in the population dynamics, even though harvesting increased annually until it reached about 110,000 in 2014, indicating that harvesting was not related to the population dynamics. In addition, although no effects of density dependence were confirmed, maximum snow depth during winter decreased deer density at the management unit scale. Harvesting represents a major source of mortality in the Kyushu Island population because of the absence of predators. Although, approximately 110,000 sika deer were harvested annually after 2014, it is surprising that the effect of harvesting on population dynamics was not significant. A main cause of no reduction of the population was that the population used to determine the harvest number was underestimated. In addition, it was indicated that multi-management units need to manage the core areas because the high-density core areas were located across a few management units. This study highlights the difficulties involved with wide-area management of large herbivores and points out the importance of accurate stock assessment, reduction of the risk of management failure, and cooperation among management units. Our research is an important contribution to the study of the effects of large-scale harvesting in a large geographic area.

Density-dependent body condition and recruitment in a tropical ungulate

2008 ◽  
Vol 86 (1) ◽  
pp. 24-32 ◽  
Author(s):  
N. Gaidet ◽  
J.-M. Gaillard
Keyword(s):  
Population Dynamics ◽  
Body Condition ◽  
Food Resource ◽  
High Density ◽  
Predation Pressure ◽  
Annual Rainfall ◽  
Large Herbivores ◽  
Density Dependent ◽  
Individual Level ◽  
The Individual

In tropical areas, annual rainfall and predation have been reported to drive population dynamics of most species of large herbivores studied so far, with little direct empirical evidence for density-dependent responses of life-history traits. We here investigated in a game ranch in Zimbabwe density-dependent responses of body condition and recruitment in an impala ( Aepyceros melampus (Lichtenstein, 1812)) population that underwent an experimental drastic reduction of density within 2 years under similar rainfall and predation pressure. Body condition of all sex and age classes was lower during the high-density year than during the low-density year, suggesting increased competition for restricted resources at high density. In addition, we observed a significant increase in population recruitment (from 0.47 to 0.80 juveniles/female) as population density declined. Our study provides a rare example of a direct density-dependent response of body condition at the individual level in a tropical ungulate species, and indicates that food resource variation controls population dynamics of impala under constant and moderate predation pressure as is commonly reported in temperate populations of large herbivores.

Population Dynamics and Regulation of a High Density Blue Tit Population

1990 ◽  
pp. 39-53 ◽  
Author(s):  
André A. Dhondt ◽  
Erik Matthysen ◽  
Frank Adriaensen ◽  
Marcel M. Lambrechts
Keyword(s):  
Population Dynamics ◽  
High Density ◽  
Blue Tit

Algae for wastewater treatment and polishing : development of methodologies for algal growth and population analysis and process optimization of algal membrane bioreactor

2015 ◽  
Author(s):  
◽  
Tianyu Tang
Keyword(s):  
Population Dynamics ◽  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Membrane Bioreactor ◽  
Algal Growth ◽  
High Density ◽  
Nutrient Recovery ◽  
Algae Cultivation ◽  
Removal Capacity ◽  
Algal Productivity

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The discharge of secondary wastewater effluent from wastewater treatment plants can lead to eutrophication in receiving water bodies due to the presence of nitrogen and phosphorus in the effluent. The research herein resulted in the development of an algal-based wastewater treatment system, which can provide efficient and cost effective wastewater treatment as well as the ability to recover nutrients in the form of algal biomass. Developing such rapid analytical methods to monitor algal activity and population dynamics and to understand the effects of system design and operation on algal performance is critical to improved wastewater treatment and nutrient recovery. This PhD thesis research presents new methods to monitor algal activity and population dynamics that can be applied for the design and operation of algal system, and to improve the algal productivity and nutrient removal capacity using a novel algal membrane bioreactor (A-MBR) technique and CO2 enrichment for high-density algae cultivation, wastewater polishing and nutrient recovery. This Ph.D. thesis research is: (1) to develop rapid and specific methods to monitor algal activity and population dynamics that can be applied for the design and operation of algal systems, (2) to improve the algal productivity and nutrient removal capacity using a novel algal membrane bioreactor (AMBR) technique, and (3) to evaluate the role of CO2 supply in high-density algae cultivation, wastewater polishing, and nutrient recovery.

scholarly journals The influence of context-dependent maternal effects on population dynamics: an experimental test

2009 ◽  
Vol 364 (1520) ◽  
pp. 1049-1058 ◽  
Author(s):  
S.J Plaistow ◽  
T.G Benton
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Density Dependence ◽  
Maternal Effects ◽  
Maternal Effect ◽  
Population Growth Rate ◽  
High Density ◽  
Parental Effects ◽  
Low Density

Parental effects arise when either the maternal or paternal phenotype influences the phenotypes of subsequent generations. Simple analytical models assume maternal effects are a mechanism creating delayed density dependence. Such models predict that maternal effects can very easily lead to population cycles. Despite this, unambiguous maternal-effect mediated cycles have not been demonstrated in any system. Additionally, much evidence has arisen to invalidate the underlying assumption that there is a simple positive correlation between maternal performance and offspring performance. A key issue in understanding how maternal effects may affect population dynamics is determining how the expression of parental effects changes in different environments. In this study, we tested the hypothesis that maternal effects influence population dynamics in a context-dependent way. Populations of the soil mite, Sancassania berlesei , were set up at high density (500 eggs) or low density (50 eggs), with eggs that were either laid by young mothers or old mothers (a previously documented maternal effect in this system). The influence of maternal age on both population and egg and body-size dynamics was only observed in the populations initiated under low density rather than high density. This difference was attributable to the context-dependence of maternal effects at the individual level. In low-density (high food) conditions, maternal effects have an impact on offspring reproductive performance, creating an impact on the population growth rate. In high density (low food), maternal effects impact more on juvenile survival (not adult size or reproduction), creating a smaller impact on the population growth rate. This context dependence of effects at the population level means that, in fluctuating populations, maternal effects cause intermittent delayed density dependence that does not lead to persistent cycles.

The effects of winter food addition on the population dynamics of Clethrionomys rutilus

1995 ◽  
Vol 73 (3) ◽  
pp. 419-426 ◽  
Author(s):  
Sabine Schweiger ◽  
Stan Boutin
Keyword(s):  
Population Dynamics ◽  
Food Supply ◽  
High Density ◽  
High Survival ◽  
Low Density ◽  
Sunflower Seeds ◽  
Peak Density ◽  
Winter Food ◽  
Clethrionomys Rutilus

Peaks in red-backed vole (Clethrionomys rutilus) populations are associated with high survival in the previous winter and we tested the hypothesis that winter persistence is determined by food supply. We supplied sunflower seeds to voles in a replicated design during winter in two consecutive years. The study began when voles were at peak density and the pattern of change was one of decline to low density over the first winter followed by constant low densities. Food addition increased persistence of individuals slightly in the first winter and significantly in the second winter. Despite higher numbers in spring and greater production of young on food grids, densities did not increase to a peak in autumn. We conclude that the food additions created local patches of high density, but these were too small to have widespread effects on vole dynamics in the area.

Planar defects in ordered (Ga,In)P

1988 ◽  
Vol 46 ◽  
pp. 902-903
Author(s):  
S. McKernan ◽  
C. B. Carter ◽  
D. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Diffraction ◽  
Vapor Phase ◽  
Growth Direction ◽  
High Density ◽  
Ordered Structure ◽  
Planar Defects ◽  
Diffraction Patterns ◽  
Ternary Semiconductors ◽  
Anion Species ◽  
Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

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