DENSIDAD POBLACIONAL DE MOSCABLANCA Bemisia spp. (HEMIPTERA: ALEYROIDIDAE) EN EL VALLE DE GUAYMAS-EMPALME, SONORA, MÉXICO/ POPULATION DENSITY OF WHITEFLY IN THE GUAYMAS-EMPALME VALLEY, SONORA, MEXICO

Biotecnia ◽  
2016 ◽  
Vol 18 (3) ◽  
pp. 9-13
Author(s):  
Juan José Pacheco-Covarrubias ◽  
Joel Soto Nolasco ◽  
Juan Manuel Valenzuela Valenzuela
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Bemisia Tabaci ◽  
The Other ◽  
Sticky Traps ◽  
Influence Of Temperature ◽  
Heat Units ◽  
Pest Infestation ◽  
Important Pest ◽  
Number Of Individuals

La mosca blanca (Bemisia tabaci) es la plaga más importante en el valle de Guaymas-Empalme, Sonora. Se determinó su densidad poblacional mediante la captura regional de adultos a través de trampas amarillas pegajosas. Los resultados indican valores de pendiente de 0.011, 0.014, 0.0045 y 0.0027 para los ciclos 2011-12, 2012-13, 2013-14 y 2014-15, respectivamente; dichos valores son diferentes estadísticamente entre sí (0.01) prueba de “t”. Por otra parte, el número promedio de individuos capturados por semana para los ciclos antes mencionados fue de 0.67, 0.80, 0.31 y 0.14, respectivamente. Finalmente, el cálculo del número de generaciones que en teoría se pueden acumular mediante Unidades Calor fue de 13.5, 9.36, 15.32, 11.96, para los ciclos antes mencionados. Los resultados no detectan evidencia determinante de la influencia de la temperatura ni del alimento sobre el crecimiento poblacional de la plaga, por lo que el manejo de focos de infestación de la plaga y el ordenamiento de fechas de cultivos son determinante para la definición del estatus fitosanitario de la plaga. ABSTRACT Whitefly is the most important pest in the Guaymas-Empalme valley, Sonora. México. The population density of whitefly was evaluated trough regional capture of whitefly adults through yellow sticky traps. The data indicate slope values of 0.011, 0.014, 0.0045 and 0.0027 for 2011-12 , 2012-13, 2013-14 and 2014-15 cycles, respectively; these values are statistically different from each other (0.01) test “t”. Moreover, the average number of individuals caught weekly was 0.67, 0.80, 0.31 and 0.14. Finally, the number of generations which in theory can be accumulated by heat units was 13.5, 9.36, 15.32, 11.96. The results did not detect evidence of the influence of temperature and crops on the population growth of the pest; on the other hand the management of outbreaks of pest infestation and crop dates control are crucial for defining the pest status.

REPRODUCTIVE CAPACITY OF TWO STRAINS OF CRYPTOLESTES TURCICUS (COLEOPTERA: CUCUJIDAE)

1968 ◽  
Vol 100 (2) ◽  
pp. 198-199
Author(s):  
P. S. Barker ◽  
James A. Johnston
Keyword(s):  
Population Density ◽  
Block Design ◽  
Insect Pest ◽  
The Other ◽  
Reproductive Capacity ◽  
Design Experiment ◽  
Pest Infestation ◽  
Randomized Block Design ◽  
Flour Mill ◽  
Cryptolestes Turcicus

Cryptolestes turcicus (Grouvelle), an insect pest of flour mills and warehouses, is distributed in Canada from Alberta to Quebec (Sinha 1965). Barker (1967) showed a difference in susceptibility to methyl bromide between two strains of C. turcicus; one of these was from the Pest Infestation Laboratory, Slough, England, and the other was from a local flour mill. A fortuitous observation suggested that there might be a difference between the reproductive capacities of these two strains. A randomized block design experiment was designed to test this hypothesis. Reproduction was observed in three sets of beetles differing in population density; each set was replicated four times.

scholarly journals Rapid plastic shifts in body size precede and determine population growth

2021 ◽  
Author(s):  
Jean Philippe Gibert ◽  
Ze-Yi Han ◽  
Daniel J Wieczynski ◽  
Andrea Yammine
Keyword(s):  
Time Series ◽  
Body Size ◽  
Population Density ◽  
Population Growth ◽  
Carrying Capacity ◽  
Rapid Evolution ◽  
The Other ◽  
Phenotypic Change ◽  
Ecological Processes ◽  
Ecological Dynamics

1. Body size is a fundamental trait linked to many ecological processes-from individuals to ecosystems. Although the effects of body size on metabolism are well-known, how body size influences, and is influenced by, population growth and density is less clear. Specifically, 1) whether body size, or population dynamics, more strongly influences the other, and, 2) whether observed changes in body size are due to plasticity or rapid evolutionary change, are not well understood. 2. Here, we address these two issues by experimentally tracking population density and mean body size in the protist Tetrahymena pyriformis as it grows from low density to carrying capacity. We then use state-of-the-art time-series analyses to infer the direction, magnitude, and causality of the link between body size and ecological dynamics. Last, we fit two alternative dynamical models to our empirical time series to assess whether plasticity or rapid evolution better explains changes in mean body size. 3. Our results clearly indicate that changes in body size precede and determine changes in population density, not the other way around. We also show that a model assuming that size changes via plasticity more parsimoniously explains these observed coupled phenotypic and ecological dynamics than one that assumes rapid evolution drives changes in size. 4. Together these results suggest that rapid, plastic phenotypic change not only occurs well within ecological timescales but may even precede -and causally influence- ecological dynamics. Furthermore, large individuals may be favored and fuel high population growth rates when population density is low, but smaller individuals may be favored once populations reach carrying capacity and resources become scarcer. Thus, rapid plastic changes in functional traits may play a fundamental and currently unrecognized role in familiar ecological processes like logistic population growth.

scholarly journals Trends and dynamics of material and energy flows in an urban context: a case study of a city with an emerging economy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Clara Inés Pardo Martínez ◽  
William Alfonso Piña ◽  
Angelo Facchini ◽  
Alexander Cotte Poveda
Keyword(s):  
Latin America ◽  
Population Growth ◽  
Construction Materials ◽  
The Other ◽  
Material Flows ◽  
Urban Context ◽  
Rapid Urbanization ◽  
Urban Agglomerations ◽  
Energy Flows ◽  
The City

Abstract Background Currently, most of the world’s population lives in cities, and the rapid urbanization of the population is driving increases in the demand for products, goods and services. To effectively design policies for urban sustainability, it is important to understand the trends of flows in energy and materials as they enter and leave a city. This knowledge is essential for determining the key elements characterizing future urban growth and addressing future supply challenges. Methods This paper presents an analysis of the energy and material flows in the city of Bogotá over the time span from 2001 to 2017. Urban flows are also characterized in terms of their temporal evolution with respect to population growth to compare and identify the changes in the main input flows, wealth production, emissions and waste in the city. Results The results of the analysis are then compared with those for other selected large urban agglomerations in Latin America and worldwide to highlight similarities and make inferences. The results show that in Bogotá, there was a decrease in some of the material flows, such as the consumption of water and the generation of discharge, in recent years, while there was an increase in the consumption of energy and cement and in the production of CO2 emissions and construction materials. Solid waste production remained relatively stable. With respect to the other large cities considered, we observe that the 10-year growth rates of the flows with respect to population growth are lower in Bogotá, particularly when compared with the other urban agglomerations in Latin America. Conclusions The findings of this study are important for advancing characterizations of the trends of material and energy flows in cities, and they contribute to the establishment of a benchmark that allows for the definition and evaluation of the different impacts of public policy while promoting the sustainability of Bogotá in the coming decades.

Plant Resistance in Some Modern Soybean Varieties May Favor Population Growth and Modify the Stylet Penetration of Bemisia tabaci (Hemiptera: Aleyrodidae)

2021 ◽  
Author(s):  
Mauricélia F Almeida ◽  
Clébson S Tavares ◽  
Euires O Araújo ◽  
Marcelo C Picanço ◽  
Eugênio E Oliveira ◽  
...  
Keyword(s):  
Population Growth ◽  
Bemisia Tabaci ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Genetically Engineered ◽  
Population Increase ◽  
Net Reproductive Rate ◽  
Bt Toxin ◽  
Demographic Performance

Abstract Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R0) 100% higher and intrinsic rate of population increase (rm) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties.

scholarly journals Recent Observations on the Mechanical Properties of Polymer Networks

1971 ◽  
Vol 44 (5) ◽  
pp. 1256-1272 ◽  
Author(s):  
P. Thirion ◽  
R. Chasset
Keyword(s):  
Crosslink Density ◽  
Room Temperature ◽  
Dynamic Properties ◽  
Polymer Networks ◽  
The Other ◽  
Dilution Ratio ◽  
Chain Entanglement ◽  
Influence Of Temperature ◽  
Terminal Zone ◽  
Crosslinking Agents

Abstract The influence of temperature, elongation, swelling or dilution ratio, crosslink density, nature of the polymers, and crosslinking agents on the dynamic properties, creep and relaxation of polymer networks is surveyed in the terminal region of the spectrum. Whereas the deformation does not change the relaxation kinetics in large ranges of extension, the crosslink density acts as a reduced variable apparently accelerating uniformly the viscoelastic processes beyond the glass transition. The other possible reductions ‘time-temperature’ and ‘time—swelling’ do not necessarily seem related to the variations of free volume. From the viewpoint of the explanation of the relaxation mechanisms in the terminal zone, the fact that the equilibrium of loosely crosslinked elastomers would only virtually be reached after several years at room temperature seem in better agreement with chain entanglement effects, either trapped or not by the permanent network, than with the dissociation of secondary linkages.

Lessons from a century of conservation translocations

2021 ◽  
Author(s):  
Shane D Morris ◽  
Katherine E. Moseby ◽  
Barry W. Brook ◽  
Christopher N. Johnson
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Historical Context ◽  
Extrinsic Factors ◽  
Global Database ◽  
Terrestrial Vertebrates ◽  
Failure Classification ◽  
High Population Growth ◽  
Number Of Individuals

Translocation—moving individuals for release in different locations—is among the most important conservation interventions for increasing or re-establishing populations of threatened species. However, translocations often fail. To improve their effectiveness, we need to understand the features that distinguish successful from failed translocations. Here, we assembled and analysed a global database of translocations of terrestrial vertebrates (n=514) to assess the effects of various design features and extrinsic factors on success. We analysed outcomes using standardized metrics i.e. a categorical success/failure classification, and population growth rate. Probability of categorical success and population growth rate increased with the total number of individuals released but with diminishing returns above about 20-50 individuals. There has been no increase in numbers released per translocation over time. Positive outcomes—reported success and high population growth—were less likely for translocation in Oceania, possibly because invasive species are a major threat in this region and are difficult to control at translocation sites. Increased rates of categorical reported success and population growth were found for Europe and North America, suggesting the key role of historical context in positive translocation outcomes. Categorical success has increased throughout the 20th century, but that increase may have plateaued at about 75% since about 1990. Our results suggest there is potential for further increase in the success of conservation translocations. This could be best achieved by greater investment in individual projects, as indicated by total number of animals released.

scholarly journals Evaluation of Resistance Development in Bemisia tabaci Genn. (Homoptera: Aleyrodidae) in Cotton against Different Insecticides

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 996
Author(s):  
Muhammad Zaryab Khalid ◽  
Sohail Ahmed ◽  
Ibrahim Al-ashkar ◽  
Ayman EL Sabagh ◽  
Liyun Liu ◽  
...  
Keyword(s):  
Bemisia Tabaci ◽  
The Other ◽  
Resistance Development ◽  
Susceptible Population ◽  
Low Level ◽  
Development Of Resistance ◽  
Major Pest ◽  
Selection For ◽  
High Level ◽  
Very High

Cotton is a major crop of Pakistan, and Bemisia tabaci (Homoptera: Aleyrodidae) is a major pest of cotton. Due to the unwise and indiscriminate use of insecticides, resistance develops more readily in the whitefly. The present study was conducted to evaluate the resistance development in the whitefly against the different insecticides that are still in use. For this purpose, the whitefly population was selected with five concentrations of each insecticide, for five generations. At G1, compared with the laboratory susceptible population, a very low level of resistance was observed against bifenthrin, cypermethrin, acetamiprid, imidacloprid, thiamethoxam, nitenpyram, chlorfenapyr, and buprofezin with a resistance ratio of 3-fold, 2-fold, 1-fold, 4-fold, 3-fold, 3-fold, 3-fold, and 3-fold, respectively. However, the selection for five generations increased the resistance to a very high level against buprofezin (127-fold), and to a high level against imidacloprid (86-fold) compared with the laboratory susceptible population. While, a moderate level of resistance was observed against cypermethrin (34-fold), thiamethoxam (34-fold), nitenpyram (30-fold), chlorfenapyr (29-fold), and acetamiprid (21-fold). On the other hand, the resistance was low against bifenthrin (18-fold) after selection for five generations. A very low level of resistance against the field population of B. tabaci, at G1, showed that these insecticides are still effective, and thus can be used under the field conditions for the management of B. tabaci. However, the proper rotation of insecticides among different groups can help to reduce the development of resistance against insecticides.

scholarly journals Trends of forest area and population and the impact of population on forest area per hectare in Serbia without APS

2012 ◽  
pp. 183-196
Author(s):  
Nenad Rankovic
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Forest Cover ◽  
Forest Policy ◽  
Forest Area ◽  
Economic Changes ◽  
Policy Measures ◽  
Per Capita ◽  
The Impact

Socio-economic changes throughout history have shaped the attitude towards the forest and most significant ones are changes in terms of population. Over the centuries population and population density have had a significant impact on deforestation and the reduction of forest areas. Therefore, it is important to check what kind of trends are concerned and how population growth affects forest areas, forest cover and forest area per capita. These elements are important for assessing the direction, intensity of activity and the degree of success in the implementation of all forest policy measures in Serbia.

scholarly journals KERAGAAN PRODUKSI, KETERSEDIAAN BERAS, DAN TRANSFORMASI LAHAN PADI INDONESIA

2008 ◽  
Vol 7 (1) ◽  
pp. 109-121
Author(s):  
Apri Andani
Keyword(s):  
Population Growth ◽  
Agricultural Production ◽  
Rice Field ◽  
Residential Area ◽  
Rice Production ◽  
The Other ◽  
Total Consumption ◽  
Food Requirement ◽  
Field Transformation

The provisions of food in order to fulfill the requirement for humankind could be followed through the implementation of the process of agricultural production. However, the food requirement could only be fulfilled self-sufficiently if food supplies were higher than the total consumption. The trend of the Indonesian rice production rises the problem that immediately must be overcome. This was caused by increasing consumption continuously resulting from the increase in population growth. Besides that, the other problems are rice field transformation, from rice field to industrial and residential area.

scholarly journals KEPADATAN POPULASI KUPU-KUPU Troides helena L. DI AIR TERJUN TUNAN DESA TALAWAAN, MINAHASA UTARA DAN TAMANHUTANRAYAGUNUNG TUMPA, MANADO

2019 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Yuri E.M. Diang ◽  
Rooije R.H. Rumende ◽  
Hanny H. Pontororing
Keyword(s):  
Population Density ◽  
Agricultural Land ◽  
Survey Method ◽  
Secondary Forests ◽  
Forest Park ◽  
North Sulawesi ◽  
Number Of Individuals

 KEPADATAN POPULASI KUPU-KUPU Troides helena  L. DI AIR TERJUN TUNAN DESA TALAWAAN, MINAHASA UTARA DAN TAMANHUTANRAYAGUNUNG TUMPA, MANADOABSTRAKKepadatan populasi menunjukan besarnya populasi dalam satuan ruang.Umumnya dinyatakan sebagai jumlah individu atau biomasa persatuan luas atau volume.  Penelitian ini bertujuan untuk menganalisis kepadatan populasi kupu-kupu  Troides helena. Penelitian ini menggunakan metode survey berupa transek garis  Penelitian ini dilakukan di dua  tempat  di Air Terjun Tunan Desa Talawaan Minahasa Utara dan Taman Hutan Raya Gunung Tumpa Manado. penelitian ini hanya dilakukan pada hutan sekunder yang sebagian besar lahannya telah dijadikan lahan pertanian. Kepadatan populasi tertinggi di daerah Air Terjun Tunan Desa Talawaan Minahasa Utara  terdapat pada Transek 2 (8 ekor/km2). Kepadatan populasi terendah terdapat pada Transek 3 (3 ekor/km2).Pada daerah Taman Hutan Raya Gunung Tumpa Manado kepadatan populasi tertinggi terdapat pada Transek 2 (74 ekor/km2).Kepadatan populasi terendah terdapat Transek 3 (14 ekor/km2).Kata kunci :Kepadatan Populasi, Troides helena, Air Terjun Tunan, TAHURA Gunung Tumpa, Sulawesi Utara POPULATION DENSITY OFTroides helenaL. ON TUNAN WATERFALL IN TALAWAAN VILLAGE, NORTH MINAHASA AND FOREST PARK OF MOUNT TUMPA, MANADO. ABSTRACTPopulation density shows the size of the population in units of space. Generally expressed as the number of individuals or biomass in area or volume. This research aims to analyze the population density of Troides helena on Tunan Waterfall in Talawaan Village, North Minahasa and Forest Park of Mount Tumpa, manado. This study used a survey method in the form of the transect line.This research only in secondary forests  is done on most of its land was made of agricultural land. The highest population density in the area Waterfall North Minahasa Talawaan Village Tunan found on Transect 2 (8 tails/km2). The low population density found in Transect 3 (3 tail/km2). In the area Forest Park of Mount Tumpa, manado.  Highest population density is found in the Transect 2 (74 tail/km2). The low population density there are Transect 3 (14 tail/km2).Keywords :Population Density, Troides helena, Tunan Waterfall, Forest Park of Mount Tumpa, North Sulawesi

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