Dynamics in Pest Status of Phytophagous Stink Bugs in the Neotropics.

In this review article, we present and discuss the main factors influencing the change in pest status of phytophagous stink bugs (Hemiptera: Heteroptera: Pentatomidae) in the Neotropics. We have surveyed the published records over the past 50 years and divided this timeframe into decades. This was done to rank in time the relative abundance (percentage) of the following species, known pests of commodities, in the Neotropical Region: the Neotropical brown stink bug, Euschistus heros (F.); the green-bellied stink bugs, Diceraeus melacanthus Dallas and D. furcatus (F.); the redbanded stink bug, Piezodorus guildinii (Westwood); the southern green stink bug, Nezara viridula (L.); and the brown-winged stink bug, Edessa meditabunda (F.). The analysis showed that E. heros, D. melacanthus, and D. furcatus, formerly minor pests, in the last decade (2010s) became major pests. The once most important pest species, N. viridula and P. guildinii, decreased their pest status in the last decade. Edessa meditabunda, which never achieved high populations, showed a tendency to increase in abundance in the last two decades (2000s and 2010s). Major factors believed to influence the dynamics of pest populations of stink bugs in the Neotropics include cropping systems (no-tillage replacing conventional soil plowing, and crop rotation); genetically modified (GM) plants (mostly plants expressing insecticidal crystalline proteins derived from Bacillus thuringiensis Berliner - Bt); change in availability of host and associated plants in the new landscape scenario; increased usage of chemicals (insecticides, fungicides, and herbicides); and change in the role of natural enemies in modern day agriculture.

Efectos del disturbio antrópico sobre las poblaciones de Leprolochus birabeni (Araneae, Zodariidae) en el Chaco Seco del noroeste de Argentina / Effects of anthropogenic disturbance on the populations of Leprolochus birabeni (Araneae, Zodariidae) in the Chaco Seco northwestern Argentina

Se conoce poco sobre la biología y la ecología de la especie mirmecófaga Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), el único representante de este género en la Argentina. Esta especie es típica de ambientes áridos del norte del país, y su estudio en el Chaco Seco es relevante, por ser una ecorregión altamente perturbada con uno de los pocos bosques subtropicales secos del mundo. El objetivo de este trabajo es estudiar la demografía de la especie teniendo en cuenta su variación estacional en ambientes nativos, y sí la ganadería y la agricultura, dos de las actividades antropogénicas más comunes de la ecorregión Chaco Seco en la provincia de Salta (Argentina) producen cambios en sus poblaciones. Se consideraron tres tipos de ambientes: nativo (NA); afectados por el ganado vacuno y caprino (NP); y afectados por la agricultura (NC). Este último correspondió a parches de vegetación nativa en medio de una matriz agrícola. En cada tipo de ambiente se consideraron tres sitios de muestreo donde se realizaron muestreos estacionales utilizando trampas de caída durante el otoño, invierno y primavera de 2006 y el verano de 2007. Se recolectaron 549 ejemplares de L. birabeni , siendo la mayoría juveniles con el 64,12% de la abundancia total, seguidos por machos (26,41%) y hembras (9,47%). A nivel de paisaje, la primavera presentó el mayor número de individuos, llegando al 44,99% de la abundancia total; mientras que el otoño mostró el porcentaje más bajo (7,83%). El incremento de los juveniles durante el invierno podría indicar una adaptación de los estadios de desarrollo a las condiciones ambientales. El mismo patrón se observó en ambientes NA y NC, pero no en los NP. Estos últimos mostraron una disminución en la abundancia de adultos a lo largo del año; mientras que las poblaciones NC mostraron un incremento en la abundancia de los machos durante la primavera, con una fuerte reducción de las hembras y los juveniles durante todo el año. [...]

Little is known about the biology and ecology of the myrmecophagic species Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), the only representative of this genus in Argentina. This species is typical of arid environments of the north of Argentina, and their study in the Chaco Seco is relevant, because is a highly disturbed ecoregion and one of the few with dry subtropical forests in the World. The aim of this work is to study the demography of this species, considering its seasonal variation in native environments, and if the livestock grazing and the agriculture, two of the most common anthropogenic activities of the Chaco Seco ecoregion, produce changes in their populations in the province of Salta (Argentina). We consider three type of environments: native (NA); affected by cattle and goats (NP); and affected by agriculture (NC). The latter corresponds to patches of native vegetation in an agricultural matrix. Three sampling sites were selected on each type of environment, where seasonal samplings using pitfall traps were performed during autumn, winter and spring (2006) and summer (2007). We collected 549 spiders of L. birabeni , with the juveniles reaching until the 64.12% of total abundance, followed by males (26.41%) and females (9.47%). At landscape level, spring season showed the highest number of individuals, reaching 44.99% of the total abundance, while autumn reported the lowest percentage (7.83%). The juveniles increase observed during the winter would indicate an adaptation to environmental conditions. The same pattern was observed in NA and NC environments, but not in NP ones. The later environments showed a decrease in the adult abundances across the seasons, while the NC populations showed an increase of male abundances during spring season with a sharp reduction of females and juveniles throughout the year. [...]

Efectos del disturbio antrópico sobre las poblaciones de Leprolochus birabeni (Araneae, Zodariidae) en el Chaco Seco del noroeste de Argentina

RESUMEN Se conoce poco sobre la biología y la ecología de la especie mirmecófaga Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), el único representante de este género en la Argentina. Esta especie es típica de ambientes áridos del norte del país, y su estudio en el Chaco Seco es relevante, por ser una ecorregión altamente perturbada con uno de los pocos bosques subtropicales secos del mundo. El objetivo de este trabajo es estudiar la demografía de la especie teniendo en cuenta su variación estacional en ambientes nativos, y sí la ganadería y la agricultura, dos de las actividades antropogénicas más comunes de la ecorregión Chaco Seco en la provincia de Salta (Argentina) producen cambios en sus poblaciones. Se consideraron tres tipos de ambientes: nativo (NA); afectados por el ganado vacuno y caprino (NP); y afectados por la agricultura (NC). Este último correspondió a parches de vegetación nativa en medio de una matriz agrícola. En cada tipo de ambiente se consideraron tres sitios de muestreo donde se realizaron muestreos estacionales utilizando trampas de caída durante el otoño, invierno y primavera de 2006 y el verano de 2007. Se recolectaron 549 ejemplares de L. birabeni , siendo la mayoría juveniles con el 64,12% de la abundancia total, seguidos por machos (26,41%) y hembras (9,47%). A nivel de paisaje, la primavera presentó el mayor número de individuos, llegando al 44,99% de la abundancia total; mientras que el otoño mostró el porcentaje más bajo (7,83%). El incremento de los juveniles durante el invierno podría indicar una adaptación de los estadios de desarrollo a las condiciones ambientales. El mismo patrón se observó en ambientes NA y NC, pero no en los NP. Estos últimos mostraron una disminución en la abundancia de adultos a lo largo del año; mientras que las poblaciones NC mostraron un incremento en la abundancia de los machos durante la primavera, con una fuerte reducción de las hembras y los juveniles durante todo el año. La abundancia de L. birabeni en ambientes NA fue mayor (41,06% de la abundancia total), siendo los valores mínimos registrados en NC (24,67%). Las dos actividades antropogénicas más comunes que afectan al Chaco Seco de la provincia de Salta modifican tanto los cambios estacionales como la representación de las diferentes etapas de desarrollo y sexos de las poblaciones nativas de L. birabeni , siendo la modificación de los ambientes nativos por la agricultura, el factor más perjudicial.

Abstract Little is known about the biology and ecology of the myrmecophagic species Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), the only representative of this genus in Argentina. This species is typical of arid environments of the north of Argentina, and their study in the Chaco Seco is relevant, because is a highly disturbed ecoregion and one of the few with dry subtropical forests in the World. The aim of this work is to study the demography of this species, considering its seasonal variation in native environments, and if the livestock grazing and the agriculture, two of the most common anthropogenic activities of the Chaco Seco ecoregion, produce changes in their populations in the province of Salta (Argentina). We consider three type of environments: native (NA); affected by cattle and goats (NP); and affected by agriculture (NC). The latter corresponds to patches of native vegetation in an agricultural matrix. Three sampling sites were selected on each type of environment, where seasonal samplings using pitfall traps were performed during autumn, winter and spring (2006) and summer (2007). We collected 549 spiders of L. birabeni , with the juveniles reaching until the 64.12% of total abundance, followed by males (26.41%) and females (9.47%). At landscape level, spring season showed the highest number of individuals, reaching 44.99% of the total abundance, while autumn reported the lowest percentage (7.83%). The juveniles increase observed during the winter would indicate an adaptation to environmental conditions. The same pattern was observed in NA and NC environments, but not in NP ones. The later environments showed a decrease in the adult abundances across the seasons, while the NC populations showed an increase of male abundances during spring season with a sharp reduction of females and juveniles throughout the year. The abundance of L. birabeni in NA environments was higher (41.06% of total abundance) and the least value was reported in NC environments (24.67%). The two most common anthropogenic activities affecting the Chaco Seco of the province of Salta modify both the seasonal changes as the representation of the different developmental stages and sexes of the native populations of L. birabeni , being the most damaging factor the modification of the native environments by the agriculture.

Efectos del disturbio antrópico sobre las poblaciones de Leprolochus birabeni (Araneae, Zodariidae) en el Chaco Seco del noroeste de Argentina / Effects of anthropogenic disturbance on the populations of Leprolochus birabeni (Araneae, Zodariidae) in the Chaco Seco northwestern Argentina

Se conoce poco sobre la biología y la ecología de la especie mirmecófaga Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), el único representante de este género en la Argentina. Esta especie es típica de ambientes áridos del norte del país, y su estudio en el Chaco Seco es relevante, por ser una ecorregión altamente perturbada con uno de los pocos bosques subtropicales secos del mundo. El objetivo de este trabajo es estudiar la demografía de la especie teniendo en cuenta su variación estacional en ambientes nativos, y sí la ganadería y la agricultura, dos de las actividades antropogénicas más comunes de la ecorregión Chaco Seco en la provincia de Salta (Argentina) producen cambios en sus poblaciones. Se consideraron tres tipos de ambientes: nativo (NA); afectados por el ganado vacuno y caprino (NP); y afectados por la agricultura (NC). Este último correspondió a parches de vegetación nativa en medio de una matriz agrícola. En cada tipo de ambiente se consideraron tres sitios de muestreo donde se realizaron muestreos estacionales utilizando trampas de caída durante el otoño, invierno y primavera de 2006 y el verano de 2007. Se recolectaron 549 ejemplares de L. birabeni , siendo la mayoría juveniles con el 64,12% de la abundancia total, seguidos por machos (26,41%) y hembras (9,47%). A nivel de paisaje, la primavera presentó el mayor número de individuos, llegando al 44,99% de la abundancia total; mientras que el otoño mostró el porcentaje más bajo (7,83%). El incremento de los juveniles durante el invierno podría indicar una adaptación de los estadios de desarrollo a las condiciones ambientales. El mismo patrón se observó en ambientes NA y NC, pero no en los NP. Estos últimos mostraron una disminución en la abundancia de adultos a lo largo del año; mientras que las poblaciones NC mostraron un incremento en la abundancia de los machos durante la primavera, con una fuerte reducción de las hembras y los juveniles durante todo el año. [...](AU)

Little is known about the biology and ecology of the myrmecophagic species Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), the only representative of this genus in Argentina. This species is typical of arid environments of the north of Argentina, and their study in the Chaco Seco is relevant, because is a highly disturbed ecoregion and one of the few with dry subtropical forests in the World. The aim of this work is to study the demography of this species, considering its seasonal variation in native environments, and if the livestock grazing and the agriculture, two of the most common anthropogenic activities of the Chaco Seco ecoregion, produce changes in their populations in the province of Salta (Argentina). We consider three type of environments: native (NA); affected by cattle and goats (NP); and affected by agriculture (NC). The latter corresponds to patches of native vegetation in an agricultural matrix. Three sampling sites were selected on each type of environment, where seasonal samplings using pitfall traps were performed during autumn, winter and spring (2006) and summer (2007). We collected 549 spiders of L. birabeni , with the juveniles reaching until the 64.12% of total abundance, followed by males (26.41%) and females (9.47%). At landscape level, spring season showed the highest number of individuals, reaching 44.99% of the total abundance, while autumn reported the lowest percentage (7.83%). The juveniles increase observed during the winter would indicate an adaptation to environmental conditions. The same pattern was observed in NA and NC environments, but not in NP ones. The later environments showed a decrease in the adult abundances across the seasons, while the NC populations showed an increase of male abundances during spring season with a sharp reduction of females and juveniles throughout the year. [...](AU)

Phylogeography of Yersinia ruckeri reveals effects of past evolutionary events on the current strain distribution and explains variations in the global transmission of enteric redmouth (ERM) disease.

Phylogeographic patterns and population genetic structure of Yersinia ruckeri, the pathological agent of enteric redmouth disease (ERM) in salmonids, were investigated on the basis of concatenated multiloci sequences from isolates of different phenotypes obtained between 1965 and 2009 from diverse areas and hosts. Sequence analyses revealed genetic differentiation among subpopulations with the largest genetic distance occurring between subpopulations of Europe and Canada and/or South America. Bayesian analysis indicated the presence of three ancestral population clusters. Mismatch distribution displayed signatures characteristic of changes in size due to demographic and spatial expansions in the overall Y. ruckeri population, and also in the geographically separate subpopulations. Furthermore, a weak signal of isolation by distance was determined. A significant positive correlation between genetic and geographical distances was observed. These results revealed that the population of Y. ruckeri has undergone both ancient and recent population changes that were probably induced by biogeography forces in the past and, much more recently, by adaptive processes forced by aquaculture expansion. These findings have important implications for future studies on Y. ruckeri population dynamics, on the potential role of genetic structure to explain variations in ERM transmission, and on the effect of past evolutionary events on current estimations of gene flow.

[Urban expansion in Mexico]. / Expansion urbana en Mexico.

PIP: The author examines urban growth in Mexico between 1960 and 1980, with a focus on the socioeconomic factors driving such growth. He makes the case that urban growth is due more to population increase in rural areas than to any expansion of the urban infrastructure.^ieng

Where have all the children gone? PROJIMO.

PIP: Few children now frequent the facilities of PROJIMO, initiated as a rehabilitation program for disabled rural children in Mexico, ever since the organization begun accepting physically disabled and socially troubled young adults. PROJIMO (the Program of Rehabilitation Organized by Disabled Youth of Western Mexico) began in 1981 as a community-based rehabilitation program run by disabled villagers. In its first years of operation, the program served primarily children suffering from disabilities caused by polio or cerebral palsy. PROJIMO quickly gained international recognition and became an inspirational model for similar programs throughout the Third World. But in 1983, PROJIMO took a decision that would transform the character of the organization. That year, after much debate, members agreed to take in Julio, a 15-year-old quadriplegic whose spinal cord injury was the result of an accidental shooting. In taking care of Julio, the team of disabled villagers had to learn an entirely new set of skills: treatment and prevention of pressure sores, the use of catheters, bowel programs, exercise activities, etc. They also had to develop ways of treating Julio's depression, giving him a sense of self-worth. Julio was followed by an influx of other young adults with spinal cord injuries. Many of these young adults came from troubled and violent backgrounds, such as Juan, an orphan who had made his way out of poverty by trafficking drugs. Juan was left paralyzed in a shootout with enemies. The new patrons have scared away PROJIMO's original audience. Parents fear bringing their disabled children to a center frequented by people raised in a culture of violence. The solution appears to be splitting PROJIMO into 2 organizations: one for disabled children and one for socially troubled adults.^ieng

Urbanization, roads, and rural population change in the Ecuadorian Andes.

"Like many developing countries Ecuador has experienced extensive ubanization in the past twenty-five years as well as a shift in the pattern of rural population change between the 1960s and 1970s. Rural places with difficult access to cities (without roads and located far from cities) gained population during the 1960s but lost population during the 1970s. Rural places with easy access to cities (i.e., located near cities or on all-weather roads) continued to gain population during the 1970s. The explanation for the differential ability of rural places to retain their population during the 1970s focuses on increases in labor circulation by peasants and growth in the numbers of small, urban-oriented manufacturing and agricultural enterprises in accessible rural areas. The article concludes with a discussion on the implications of these findings for policies to reduce rates of rural-urban migration."

Differential urban growth as a process of redistribution of population: a case study of Sao Paulo state, Brazil.

"This paper identifies the process of the differential concentration of population in urban areas....[Data for the state of Sao Paulo, Brazil, have] been subjected to an ambiguous model of development. This model is reflected in the pattern of population distribution."

Alouatta caraya: Population density and demography in Northern Argentina.

A long-term study was carried out on a black howler monkey (Alouatta caraya) population living in 150 ha of forest patches spread out in a 3,000 ha rural area in Northern Argentina. A total of 22 different groups were located between 1980 and 1984 and 11 of these were monitored regularly during 28 months. Ecological density varied between 12.14 and 12.93 groups per sq km of thall dense forest (0.80 to 1.15 ind./ha; biomass 306 to 365 kg/sq km). Solitaries and small associations of adult or subadult individuals of both sexes were also recorded but occupied habitats of inferior quality. Mean sizes of reproductive groups varied from 6.4 to 8.4 and the range was 3 to 15 individuals. Reproductive groups had 1 to 3 adult males, 1 to 3 adult females, and several immatures. Sex ratio was biased toward females among the adults but it varied in other age classes. Births occurred throughout the year showing a peak in the colder and drier season. Subadult or young adult males and females dispersed from suspected natal groups and became solitaries or joined associations. Males invaded groups and displaced or coexisted with resident males. Infanticides and disappearances of infants were associated with male changes. Comparative censuses on an island not far from the main study area showed higher density and biomass (2.8 ind./ha; 1,117 kg/sq km) and different group sizes and composition. Habitat features as well as the history of each study site may account for the observed demographic differences.

[Changes of trends of internal migration, urbanization and village settlement in Cuba]. / Zmeny v trendech vnitrni migrace, urbanizace a ve vesnickem osidleni na kube.

PIP: Changes of space settlement and location of population are a consequence of the complex social conditions and are therefore strongly influenced by social and economic formation. Under capitalism, there existed in Cuba a considerable difference of living conditions between Havana and other towns, as well as in the country-side. In 1953, already 35% of the urban population lived in Havana; almost the whole industrial and trade activity was concentrated in Havana and in several other towns. A large dispersion was especially characteristic for the rural settlement. Immigration to Havana and to several further towns was traditionally very intensive. However, new economic policy after the revolution has limited this immigration by the development of medium-size towns and by developing large-scale agricultural production - a unique case in Latin America. Urban population reached 68.2% in 1981, while the share of population living in the capital declined from 20.8% in 1953 to 19.8% in 1981. During the session of the National Assembly of People's Power in December 1983, Castro proclaimed that Cuba was probably the only country of Latin America not having any problem with the growth of the capital. The author includes tables comparing living standard development in the provinces of maximum and minimum population dispersion. The changes undergone in the field of internal migration, urbanization, and characteristics of rural settlement in Cuba relate to given development strategy and they are a logical consequence of profound social changes of the society. However, there exist some handicaps preventing an efficient development; for instance, the problem of directing migration to the regions, where the manpower is required. More necessary is the stabilization of urban settlement and, at the same time, a definitive elimination of territorial differences of the living standard. This is not an easily realizable process due to the need of considerable investments not confined to the sphere of material production.^ieng

[The metropolitan regions: the estimated population for 1985 and 1990]. / As regioes metropolitanas: a populacao estimada para 1985 e 1990.

PIP: Current trends in urban population size and growth in Brazil are described. It is noted that the population of nine major urban areas has grown from 24.1 million in 1970 to 35.1 million in 1980 and will likely reach 47.8 million by 1990, with Sao Paulo the fastest-growing urban area. Data are from official sources.^ieng

[The cities of Brazil in the future]. / As cidades no Brasil do futuro.

PIP: Projected future trends in urbanization in Brazil are reviewed. The author notes that by the year 2000, Brazil will have a total population of 180 million, of whom 75 percent will live in urban areas. The relative percentage of the urban population who will live in the two major metropolitan areas is also outlined.^ieng

[Urbanization in Latin America: the process of the development of peripheries to metropolitan areas]. / La urbanizacion en America Latina: el proceso de constitucion de periferias en las areas metropolitanas.

PIP: Trends in urbanization in Latin America are reviewed. The focus is on the development of peripheral, low-income urban areas adjoining major urban centers during the period since the 1970s.^ieng

[Trends and characteristics of urbanization in the Third World, the day before yesterday to the day after tomorrow (1900-2025)]. / Tendances et caracteristiques de l'urbanisation du Tiers Monde d'avant-hier a apres-demain (1900-2025).

PIP: This article reviews the history of Third World urbanization, examines the evolution of the urban population from 1970-80 based on the 1st results of the 1980 round of censuses, and examines the prospects for urbanization through the end of the century and the year 2025. From 1910 to World War II the urban population in all Third World countries grew more rapidly than the total population. Both rates of growth were moderate compared to subsequent rates. Total Third World population grew by about .9%/year while the urban population grew at 2.2%/year. From 1950-80 total population grew at 2.2% and the urban population by 4.6%. The urban growth took place in the absence of economic developments capable of explaining or justifying it. Urban growth accounted in large part for the extraordinary increase in cereal importation to the Third World. In 1980 it was estimated that 26.5% of the population if Africa, 63.1% in Latin America, and 25.4% in Asian countries excluding China were urban. A characteristic of third World urbanization is the strong concentration of population in large cities; 43% of the urban population currently lives in cities with population of over 500,000. In Third World market countries, total population growth from 1970-80 is provisionally estimated at 2.5-2.6%/year, while according to UN estimates urban population growth amounted to 4.2%/year and other estimates place population growth amounted to 4.2%/year and other estimates place it at 4.4%/year. The growth of the urban population in China from 1970-80 was estimated at 3.3%/year by the UN. During the 75 years from 1950-2025, the Third World urban population is expected to multiply by a factor of 16, from less than 200 million to over 3 billion. The urban population in 2025 projected by the UN amounts to 837 million in Africa, 724 million in Latin America, and 1.6 billion in Asian market countries, but there is some suggestion that the projection errs on the low side. Increases in food production on the order of 1.9%/year will be required through 2025 to feed the new urban population at the current level. Around the year 2000, cities of 1 million or more will contain about 46% of the urban population and 21% of the total population. The largest Third World cities will continue to grow despite their poor living conditions and lack of economic justification, and the low incomes of the inhabitants will increase the difficulty of improving living standards. Predictions as far ahead as 2025 are hazardous, but it is likely that the rate of growth of the largest cities will have abated somewhat.^ieng

Primary health care in the context of rapid urbanization.

PIP: A review of demographic trends and health and social problems in the fast growing urban areas of the world indicates that, in the future, increasing numbers of people will be living in precarious socioeconomic conditions which impede the achievement of health. It is estimated that from 4.4 billion in 1980 the world's population will increase to 6.2 billion by the year 2000. The urban population will increase from 1.8 to 3.2 billion during the same period, over 2 billion of which will be in developing countries. The rapid and often uncontrollable demographic growth of cities, especially in the developing world, stimulates the demand for resources, intensifies their utilization and creates an intolerable pressure on the urban infrastructure and physical environment. A number of action oriented projects to combat disease and contamination have been successful. Projects in Addis Ababa, Ethiopia, Colombo, Sri Lanka, Hyderabad, India, Guayaquil, Ecuador, Lima, Peru, and Rio de Janeiro have been implemented under a partnership among WHO, UNICEF, the Netherlands Aid Agency, the World Bank, and other international organizationals and governments. These projects all emphasize the fundamental role of community organizations, especially that of women; low-cost technology and the need to mobilize and efficiently use locally available resources; an ecological multisectoral concept of health whereby action concerning the environment, education, income generation and the availability of food, all with a powerful disease preventive potential, carry equal if not greater weight than the efforts to provide the population with health centers or implement curative practices. All these projects are focused on marginal groups; many were initiated by imaginative individuals or groups with a considerable amount of social orientation and motivation, and often, at least in the beginning, without the support of governments, nongovernmental or international organizations. It is important to study these projects in their accomplishments and failures; to help describe them and disseminate related information when appropriate; and to promote political and technical support for those which are successful so that they can rapidly come out of the experimental/demonstration phase and be expanded to become part of routine programs.^ieng

Metropolitan migration and population growth in selected developing countries.

PIP: The purpose of this article is to estimate the components of metropolitan population growth in selected developing countries during 1960-1970 period. The study examines population growth in 26 cities: 5 are in Africa, 8 in Asia, and 13 in Latin America, using data from national census publications. These cities in general are the political capitals of their countries, but some additional large cities were selected in Brazil, Mexico, and South Africa. All cities, at the beginning of the 1960-1970 decade had over 500,000 population; Accra, the only exception, reached this population level during the 1960s. Some cities had over 4 million residents in 1970. Net migration contributed about 37% to total metropolitan population growth; the remainder of the growth is attributable to natural increase. Migration has a much stronger impact on metropolitan growth than suggested by the above figure: 1) Several metropolitan areas, for various reasons, are unlikely to receive many migrants; without those cities, the share of metropolitan growth from net migration is 44%. 2) Estimates of the natural increase of migrants after their arrival in the metropolitan areas, when added to migration itself, changes the total contribution of migration to 49% in some metropolitan areas. 3) Even where net migration contributes a smaller proportion to metropolitan growth than natural increase, the rates of net migration are generally high and should be viewed in the context of rapid metropolitan population growth from natural increase alone. Finally, the paper also compares the components of metropolitan growth with the components of growth in the remaining urban areas. The results show that the metropolitan areas, in general, grow faster than the remaining urban areas, and that this more rapid growth is mostly due to a higher rate of net migration. Given the significance of migration for metropolitan growth, further investigations of the effects of these migration streams, particularly with respect to in-migration and out-migration, would greatly benefit understanding of the detailed and interconnected process of population growth, migration, employment and social welfare of city residents.^ieng

[Rural-urban population redistribution between 1970 and 1980 (a micro-regional analysis)]. / Redistribuicao rural-urbana da populacao entre 1970-1980 (analise segundo as microrregioes)

PIP: Changes in rural-urban population distribution in Brazil from 1970 to 1980 are analyzed using census data. Trends examined include spatial redistribution throughout the country, rapid urbanization, the decline in the size of the rural population in the state of Parana, agricultural expansion in the northern and central-western regions, and the increase of the rural population within metropolitan areas. (summary in ENG)^ieng

[Observations on rural and urban population changes in Brazil from 1940 to 1980]. / Observacoes sobre a evolucao da populacao rural e urbana do Brasil no periodo 1940 a 1980.

PIP: Preliminary data from the 1980 census are used to analyze changes in rural-urban population patterns in Brazil between 1940 and 1980. The data are presented in four tables and three maps that show changes by region and federal unit.^ieng

[Evolution of the urban and rural population in the 11 administrative regions of the state of Sao Paulo]. / Evolucao da populacao urbana e rural nas 11 regioes administrativas do estado de Sao Paulo, 1940-1970.

PIP: This paper describes the evolution of the urban and rural population in the 11 administrative regions of the state of Sao Paulo, Brazil, and to establish the role of the new municipalities. The number of municipalities grew from 270 during 1940-50 to 505 during 1960-70; in the same period the annual population growth in urban areas increased from 3.72% to 5.56%. The great urbanization process in Sao Paulo began after 1940; before the date 56% of the population lived in rural areas. The growth of urbanization during the period 1940-70 was prompted mainly by the decline in the production of coffee together with a great expansion of industry, leading to a massive movement of workers from the coffee fields to the newly industrialized areas. Improvements in the road and railway system greatly contributed to these changes. This situation has brought under attack, on the part of legislators, the old criteria used to define urban and rural population in Brazil, criteria still based on an ancient law which does not take into consideration the activities carried out by the population in a specific area.^ieng