PREDATION BY WASPS, BIRDS, AND MAMMALS ON HYPHANTRIA CUNEA

1972 ◽  
Vol 104 (10) ◽  
pp. 1581-1591 ◽  
Author(s):  
R. F. Morris
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Social Wasps ◽  
Rapid Population Growth ◽  
Hyphantria Cunea ◽  
Regulatory Influence

AbstractPredation by birds and social wasps (Vespula spp.) on larval colonies of Hyphantria cunea Drury was studied in both natural and artificial populations, and predation by mammals on overwintering pupae in the ground was studied in artificial populations. The species of predators are listed and some important differences in their habits of attack are described. Per cent predation by birds is directly related to the population density of H. cunea over a range of densities, but inversely related after density exceeds this range. When habitat and weather favor rapid population growth, H. cunea "escapes" from the population range in which predation exerts a regulatory influence.

The Role of Predators and Other Biotic Agents in Regulating the Population Density of Phytophagous Mites in Ontario Peach Orchards

1966 ◽  
Vol 98 (8) ◽  
pp. 808-820 ◽  
Author(s):  
W. L. Putman ◽  
D. H. C. Herne
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Tetranychus Urticae ◽  
Considerable Extent ◽  
Panonychus Ulmi ◽  
Apple Orchards ◽  
Rapid Population Growth ◽  
One Year ◽  
Heavy Mortality

AbstractMore than 40 species of insects and arachnids attack Panonychus ulmi (Koch), Tetranychus urticae Koch, T. canadensis (McGregor), Bryobia arborea Morgan and Anderson, or Aculus cornutus (Banks) in peach orchards of the Niagara Peninsula. The most effective predators attacking P. ulmi are Typhlodromus caudiglans Schuster, Haplothrips faurei Hood, Stethorus punctillum Weise, and Chrysopa spp. Peach orchards lack the predatory mirids characteristic of apple orchards. A condition, presumably disease, caused heavy mortality in one year. Endemic densities of P. ulmi are maintained in that state by predators, chiefly T. caudiglans, that subsist to a considerable extent on other sources of food, whereas epidemics of P. ulmi are reduced largely by other predators, chiefly H. faurei and S. punctillum, that increase in numbers by feeding on the mite during its period of rapid population growth but exert their greatest effect later in the season by destroying the winter eggs.

scholarly journals Which Gridded Population Data Product Is Better? Evidences from Mainland Southeast Asia (MSEA)

2021 ◽  
Vol 10 (10) ◽  
pp. 681
Author(s):  
Xu Yin ◽  
Peng Li ◽  
Zhiming Feng ◽  
Yanzhao Yang ◽  
Zhen You ◽  
...  
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Southeast Asia ◽  
Anthropogenic Impacts ◽  
Local Population ◽  
Population Data ◽  
Rapid Population Growth ◽  
Ongoing Research ◽  
New Findings ◽  
Mainland Southeast Asia

The release of global gridded population datasets, including the Gridded Population of the World (GPW), Global Human Settlement Population Grid (GHS-POP), WorldPop, and LandScan, have greatly facilitated cross-comparison for ongoing research related to anthropogenic impacts. However, little attention is paid to the consistency and discrepancy of these gridded products in the regions with rapid changes in local population, e.g., Mainland Southeast Asia (MSEA), where the countries have experienced fast population growth since the 1950s. This awkward situation is unsurprisingly aggravated because of national scarce demographics and incomplete census counts, which further limits their appropriate usage. Thus, comparative analyses of them become the priority of their better application. Here, the consistency and discrepancy of the four common global gridded population datasets were cross-compared by combing the 2015 provincial population statistics (census and yearbooks) via error-comparison based statistical methods. The results showed that: (1) the LandScan performs the best both in spatial accuracy and estimated errors, then followed by the WorldPop, GHS-POP, and GPW in MSEA. (2) Provincial differences in estimated errors indicated that the LandScan better reveals the spatial pattern of population density in Thailand and Vietnam, while the WorldPop performs slightly better in Myanmar and Laos, and both fit well in Cambodia. (3) Substantial errors among the four gridded datasets normally occur in the provincial units with larger population density (over 610 persons/km2) and a rapid population growth rate (greater than 1.54%), respectively. The new findings in MSEA indicated that future usage of these datasets should pay attention to the estimated population in the areas characterized by high population density and rapid population growth.

scholarly journals Rapid Population Growth in Chinese Floodplains from 1990 to 2015

2018 ◽  
Vol 15 (8) ◽  
pp. 1602 ◽  
Author(s):  
Yongqiang Fang ◽  
Shiqiang Du ◽  
Paolo Scussolini ◽  
Jiahong Wen ◽  
Chunyang He ◽  
...  
Keyword(s):  
Climate Change ◽  
Population Density ◽  
Population Growth ◽  
Flood Risk ◽  
Socioeconomic Development ◽  
Total Population ◽  
Spatiotemporal Pattern ◽  
Rapid Population Growth ◽  
Over Time

Although China suffers from frequent and disastrous floods, the spatiotemporal pattern of its population living in the floodplain (PopF) is still unknown. This strongly limits our understanding of flood risk and the effectiveness of mitigation efforts. Here we present the first quantification of Chinese PopF and its dynamics, based on newly-available population datasets for years 1990, 2000, 2010, and 2015 and on a flood map. We found that the PopF in 2015 was 453.3 million and accounted for 33.0% of the total population, with a population density 3.6 times higher than outside floodplains. From 1990 to 2015, the PopF increased by 1.3% annually, overwhelmingly faster than elsewhere (0.5%). A rising proportion (from 53.2% in 1990 to 55.6% in 2015) of the PopF resided in flood zones deeper than 2 m. Moreover, the PopF is expected to increase rapidly in the coming decades. We also found the effect of flood memory on controlling PopF growth and its decay over time. These findings imply an exacerbating flood risk in China, which is concerning in the light of climate change and rapid socioeconomic development.

scholarly journals Population priorities: the challenge of continued rapid population growth

2009 ◽  
Vol 364 (1532) ◽  
pp. 2977-2984 ◽  
Author(s):  
Adair Turner
Keyword(s):  
Nineteenth Century ◽  
Population Density ◽  
Population Growth ◽  
Economic Performance ◽  
Developed Countries ◽  
Modern World ◽  
World Population ◽  
High Fertility ◽  
Rapid Population Growth ◽  
Per Capita

Rapid population growth continues in the least developed countries. The revisionist case that rapid population could be overcome by technology, that population density was advantageous, that capital shallowing is not a vital concern and that empirical investigations had not proved a correlation between high population growth and low per capita income was both empirically and theoretically flawed. In the modern world, population density does not play the role it did in nineteenth-century Europe and rates of growth in some of today's least developed nations are four times than those in nineteenth-century Europe, and without major accumulation of capital per capita , no major economy has or is likely to make the low- to middle-income transition. Though not sufficient, capital accumulation for growth is absolutely essential to economic growth. While there are good reasons for objecting to the enforced nature of the Chinese one-child policy, we should not underestimate the positive impact which that policy has almost certainly had and will have over the next several decades on Chinese economic performance. And a valid reticence about telling developing countries that they must contain fertility should not lead us to underestimate the severely adverse impact of high fertility rates on the economic performance and prospects of many countries in Africa and the Middle East.

The Political Economics of Population Growth: The Case of China

1971 ◽  
Vol 23 (2) ◽  
pp. 245-272 ◽  
Author(s):  
Pi-Chao Chen
Keyword(s):  
Economic Development ◽  
Quantitative Analysis ◽  
Population Growth ◽  
Historical Data ◽  
Historical Record ◽  
The Political ◽  
High Population Density ◽  
Rapid Population Growth ◽  
The World ◽  
Simon Kuznets

Some economists argue that high population density and rapid population growth are not in themselves impediments to economic development. On the basis of a quantitative analysis of historical data, Simon Kuznets, for instance, concludes that, historically, rates of economic development have not significantly correlated, either positively or negatively, with rates of population growth. Similarly, E. E. Hagen observes that “nowhere in the world has population growth induced by rising income been sufficient to halt the rise in income. … The historical record indicates that rise in income in these societies has failed to occur not because something thwarted it, but because no force has been present to cause income to rise.

PREDATION BY INSECTS AND SPIDERS INHABITING COLONIAL WEBS OF HYPHANTRIA CUNEA

1972 ◽  
Vol 104 (8) ◽  
pp. 1197-1207 ◽  
Author(s):  
R. F. Morris
Keyword(s):  
Population Dynamics ◽  
Nova Scotia ◽  
North America ◽  
Population Density ◽  
New Brunswick ◽  
Numerical Response ◽  
Initial Number ◽  
Hyphantria Cunea ◽  
The North ◽  
The Mean

AbstractThe number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

scholarly journals Reproduction and survival of Muscina stabulans under laboratory conditions

2010 ◽  
Vol 40 (3) ◽  
pp. 674-677 ◽  
Author(s):  
Rodrigo Ferreira Krüger ◽  
Paulo Bretanha Ribeiro ◽  
Simone Giehl Erthal ◽  
Og DeSouza
Keyword(s):  
Population Growth ◽  
Quantitative Estimate ◽  
Intrinsic Rate ◽  
Reproduction Rate ◽  
Rapid Population Growth ◽  
Artificial Diets ◽  
Adaptation Capacity ◽  
Laboratory Conditions ◽  
Published Report ◽  
Rearing Conditions

This is the first published report concerning reproduction and survival using life table analyses of fertility and survival for Muscina stabulans maintained under laboratory conditions with artificial diets. The intrinsic rate of growth, reproduction rate and average generational time were obtained, suggesting a rapid population growth under these rearing conditions. These findings permitted the creation of time models of survival and oviposition, as well as a quantitative estimate of the adaptation capacity of this species.

scholarly journals California Futures

2012 ◽  
Vol 2 (2) ◽  
pp. 37-54
Author(s):  
Dowell Myers
Keyword(s):  
Population Growth ◽  
Baby Boomers ◽  
Demographic Change ◽  
House Prices ◽  
Shared Understanding ◽  
Rapid Population Growth ◽  
Proposition 13 ◽  
Racial Change ◽  
Recent Trends ◽  
Brighter Future

California needs a new guiding narrative for shared understanding and for directing public decisions about threats and opportunities in the state. Misleading and counterproductive guidance is provided by narratives that are no longer supported by recent trends. Ongoing changes related to two specific guiding narratives are described. In the first, support for Proposition 13 was founded on explosive increases of house prices in the 1970s, along with assumptions of continued migration of newcomers willing to pay higher prices and the higher taxes needed to offset discounts for oldtimers. A second narrative of demographic change reacts negatively to rapid population growth, soaring immigration and racial change. Remarkably, virtually all the premises in these two narratives have been overturned by events. Instead, a different set of urgent problems and opportunities have emerged that require a new guiding vision. In place of exploding house prices, tax assessments have collapsed and we struggle to revive the housing market. Young buyers are asked to pay the highest taxes, but today it is the young not the old who are vulnerable and threatened. While before it was a struggle to keep up with migration from outside California, immigration has declined and today the growth is homegrown. Meanwhile, the aging baby boomers are about to create a crisis of replacement workers, taxpayers and home buyers. Cultivating the new homegrown generation is our paramount need. Today the story of California is completely reversed, yet adherence to the old narratives blocks recognition of the path to a brighter future.

scholarly journals Design of vertical fisherman village in Penjaringan with sustainable development concept

2021 ◽  
Vol 878 (1) ◽  
pp. 012020
Author(s):  
M Yudha ◽  
U Siahaan ◽  
R Ismanto
Keyword(s):  
Sustainable Development ◽  
Population Growth ◽  
Economic Life ◽  
Behavior Patterns ◽  
Rapid Population Growth ◽  
Fishing Village ◽  
Open Land ◽  
Vertical Development ◽  
Narrow Area ◽  
Limited Height

Abstract Indonesia is known as an archipelago state that has more than 17,000 islands with a coastline of more than 81,000 kilometers. Therefore, the economic life of the Indonesian nation is largely centered on the coastal areas. Population growth along the coastline has resulted in fishermen choosing to live close to their source of life and building their economy there. Rapid population growth, and the scarcity of available residential land resulted in fishermen building denser settlements, expanding towards the sea and ultimately giving the impression of slums along the coast. It is felt that vertical settlements (flats) will provide solutions to problems in the conditions of these slum settlements. The effort to rejuvenate the fishing village in Penjaringan Village is the topic of this research with the limited vertical settlement approach, which takes into account: behavior patterns, habits, activities and daily needs of fishermen. A vertical development with a limited height is also seen as fulfilling the concept of sustainable development, where all fishing activities can be accommodated on a narrow area of land and do not sacrifice too much open land which is already small in the coastal area. In addition, fishermen’s life and cooperation between them can be facilitated by carrying out a compact upward design. This is one solution that will differentiate this fishing village from other settlements. This development is declared successful if all the goals that have been set together can be achieved and bring benefits to the group of residents.

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