Population dynamics of a migrant skipper butterflyParnara guttata (Lepidoptera: Hesperiidae) II. Survival rates of immature stages in paddy fields

Summary Survival rates and mortality factors of a migrant skipperParnara guttata were censused in paddy fields in 4 localities of central and western Japan during 1975–1980, and 10 life tables were developed for 3 generations. Mortality rates of eggs, older larvae and pupae were high but those of younger larvae were very low. The high mortality rate was caused by parasitoids. Ten primary and 6 secondary parasitoids were recorded. Out of three egg parasitoids,Telenomus sp. was predominant. Larval parasitoids,Apanteles baoris andPediobus mitsukurii which are specific to genusParnara were predominant in wet land habitat, i.e. paddy land. On the other hand, tachinid flies which have a wide host range and a high searching ability were predominant in dry land habitats. Mortalities of eggs and pupae contribute more to the change in the total mortality of immature stages than those of other stages. egg parasitoids which are the major mortality factor of eggs acted density-dependently but larval and pupal parasitoids did not do so. The total mortality of immature stages occurred more or less density-dependently. Larval density on rice plants scarecely affected the survival rate of larvae.     

Life tables for worker honeybees

Summary Life tables for worker honeybees covering all life span, and those for adults, were prepared for three seasonal cohorts,June bees, July bees andwintering bees. Survivorship curves forJune andJuly bees show a convex type being exceptional for insects, with relatively high mortality at egg and feeding larval stages and at later adult stage after most bees became potential foragers. Adult longevity greatly lengthens inWinteriing bees and survivorship curve drops approximately with the same rate. A remarkable similarity of survivorship curves for men and honeybees was demonstrated, apparently due to highly developed social care in both. Some comments were given on mortality factors. The importance of life tables for population researches was shown by applying our result to the population growth curve made byBodenheimer, based upon the data byNolan. At the asymptote of the uncorrected curve, the ratio of total population estimated by uncorrected curve to that by corrected curve reaches about 3∶2. Contribution No. 821 from the Zoological Institute, Faculty of Science, Hokkaido University, Sapporo, Japan. Contributions from JIBP-PT No. 45. This study was in part supportod by a grant in aid from the Ministry of Education for the special project research, “Studies on the dynamic status of biosphere.” Population and bioeconomic studies on the honeybee colonies. II. We express our sincere thanks to Dr. YosiakiIt?, National Institute of Agricultural Sciences, Tokyo, for his kind stimulation and advices to the present work.     

The plastic reproductive allocation of the cruciferous perennialRorippa indica in response to different degrees of feeding damage

Summary The degree of feeding damage in the wild to the cruciferous perennialRorippa indica (L.) Hieron ranged from 0% (not damaged) to 100% (heavily damaged). However, “not damaged” and “heavily damaged” individuals did not differ in the relative suitability of their intrinsic traits forP. rapae, which caused the heaviest damage on the plant. Therefore, the different degrees of feeding damage may be due to variability in the extrinsic traits of the plant, that is, it may be determined by the habitat conditions where individual plants exist. Furthermore,R. indica allocated more resource to seed production at the expense of the roots when it was experimentally subjected to heavy leaf damage. The result suggested thatR. indica individuals may escape, by means of seed dispersal and seed dormancy, from unfavorable habitats where they are heavily damaged by herbivores.     

Spatial pattern analysis of the incidence of aster yellows disease in lettuce

The degree of aggregation of lettuce plants infected by aster yellows phytoplasma (AYP) was investigated in 12 fields from three experiments. Position of diseased and healthy plants was mapped in a 6–9×12-m section of each field; for most analyses, fields were divided into 10-plant quadrats. Mean disease incidence (p) ranged from 0.01 to 0.30. The frequency of diseased plants was described by the beta-binomial distribution, with an index of aggregation (θ) ranging from 0 to 0.17, positively correlated withp, and generally increasing over time within a field. Distance-class analysis revealed a core-cluster size of only a few plants. However, spatial autocorrelations ofp between quadrats were not significant, indicating that the scale of spatial pattern was small, generally less than 10 plants. An overall measure of aggregation was given by the slope parameter of the binary form of the power law, in which the log of the calculated variance is regressed on the log of the theoretical variance for a binomial distribution. The slope was 1.18 and significantly different from 1. Results for this “simple-interest” disease are interpreted in relation to the persistent transmission of AYP by its aster leafhopper vector.     

Comparison of life tables between the solitary eumenid waspAnterhynchium flavomarginatum and the subsocial eumenid waspOrancistrocerus drewseni to evaluate the adaptive significance of maternal care

Summary I compared life tables between the solitary eumenid waspAnterhynchium flavomarginatum Smith and the subsocial eumenid waspOrancistrocerus drewseni Saussure in Kyoto, Japan, during 1980–1983. The subsocial eumenid is parthenogenetic in this study area. There were 9 identified mortality factors in the solitary eumenid and 7 in the subsocial eumenid, 6 of which were common to the two eumenids. The important differences of mortality between the two eumenids were seen in the egg, larval, and prepupal stages. In the egg stage, mortality by the phorid flyMegaselia sp. was much lower in the subsocial eumenid (1.4%) than in the solitary eumenid (15.0%) likely because of the matenal care of the subsocial eumenid (progressive provisioning and other related behavior), which reduced predation pressure. In the larval stage, mortality by the miltogrammine flyAmobia distorta was also lower in the subsocial eumenid (8.1%) than in the solitary eumenid (23.8%) also probably because of the maternal care of the subsocial eumenid. A comparison of mortality in the two eumenids between the stable, long continuing natural nest sites and the additional temporal ones showed that the phorid fly remained near its birth place and parasitized stable nest sites. The miltogrammine fly followed returning eumenid wasps and parasitized those nest sites that have a high host density. In the prepupal stage, mortality by endogenous death was higher in the subsocial eumenid than in the solitary eumenid. Mortality due to the rhipiphorid beetle was also higher in the subsocial eumenid probably due to more frequent flower-visits by the subsocial eumenid. The defense mechanism of the subsocial eumenid was discussed in relation to the evolution of subsociality. Contribution to the ecological studies of the eumenid wasps. I.     

Hope and Adaptation to Old Age: Their Relationship with Individual-Demographic Factors

This study examined the relationship between hope as disposition, adaptation to old age, and individual-demographic factors. One hundred and fifty older adults, aged 60–93 years old, completed the Adult Dispositional Hope Scale developed by Snyder et al. [1991, Journal of Personality and Social Psychology, 60, pp. 570–585], and the Adaptation to Old Age Questionnaire developed by Efklides et al. [2003, European Psychologist, 8, pp. 178–191]. Factor analyses revealed 2 factors for hope, “Pathways Thought” and “Agency Thinking”, and 4 factors for adaptation to old age, “Health Comparison”, “General Adaptation/Self-Efficacy”, “Self-Control”, and “Generativity”. Regression analyses showed that hope as pathways thought predicted all factors of adaptation, whereas hope as agency thinking predicted only “General Adaptation/Self-Efficacy” and “Self-Control”. There were also some effects of gender, education, marital status, place of residence, and health status on specific aspects of adaptation to old age.     

Survival Convergence and the Preceding Mortality Crossover for Two Population Subgroups

In this paper, we present and develop the argument that if the survival functions for two population subgroups converge in later life, a mortality crossover must precede the occurrence of this convergence. Specifically, two survival curves, S ₁(x) and S ₂(x), associated with two distinct population subgroups, G₁ and G₂, tend to converge before all members die out, as often observed and anticipated. This convergence leads to an increased mortality acceleration for the “advantaged” group, and eventually fosters the occurrence of a mortality crossover. We present a mathematical proof for this relationship and offer several explanations for the mechanisms involved in the process of survival convergence and the preceding mortality crossover. This new presentation demonstrates that mortality crossover is a highly observable demographic event given the trend of survival convergence in later life.     

Population behaviour of the southern green stink bug,Nezara viridula, with special reference to the developmental stages of early-planted paddy

Summary Population behaviour of adults and 5th-instar nymphs ofNezara viridula L. was analysed by means of the marking-and-recapture method in an early-planted paddy field. The field contained five varieties of rice which differend in growth states. It was estimated that a total of more, than 7,000 adults of the first generation, in which at least 3,000 were females, invaded the field from early July to middle August. Egg-mass census data, however, indicated that only 10 per cent or less of the females participated in egg-laying. This was largely due to the, low rate of adult survival. The adults preferred younger plants, for both feeding and oviposition. The method described byIwao et al. (1966) permitted estimate that 3,300–3,400 of the 5 th-instar nymphs and 1,100–1,200 of the adults of the second generation were produced from 298 egg-masses (25, 700 eggs); while 95–6 per cent of the individuals were thought to have died before reaching adulthood. Most of the 5 th-instar nymphs moved less than 4 m in three days as long as the condition of food plants remained suitable, but they tended to move more towards younger plants when those on which they lived became too mature. The apparent survival rate of the second generation adults was very low, probably due both to a rapid emigration and a high mortality of newly-emerged adults.     

Estimatingdendroctonus frontalis (Coleoptera: Scolytidae) daily infestation dynamics

Mathematical procedures are given to estimate infestation totals and daily life stage arrivals, departures, and mortality ofDendroctonus frontalis Zimmermann for an infested tree in the field. These estimates are based on minimal sample data and are designed to utilize all available information. Daily arrival estimates for larvae, pupae, and callow adults are obtained by indirect analysis without direct observation of these stages. The procedures are applied to 147 infested trees, and the results are transformed to a common time basis to obtain daily expectations by life stage for an “average” tree. These expectations suggest optimal times for field sampling or relative times of sampling when optimal times are missed. Expected daily arrival distributions by life stage for a single egg and a single attacking adult are given. Procedures are given for utilizing collateral information to obtain an infestation total and daily arrival estimates for a boundary life stage. The results of this study are applicable to anyD. frontalis field study, and the procedures given are applicable to any bark inhabiting insect having similar habits.     

Child support and non-resident fathers’ contact with their children

The paper presents a model of a non-resident father’s child support and contact with his child, which combines the public good treatment of “child quality” with “trade” in father–child contact time in a setting of non-cooperative interaction. It predicts that father’s income and mother’s non-labour income should have exactly the same effect on the frequency of father–child contact if he chooses to make lump sum payments to the mother. If he does not or there is a binding child support payment order, they have effects opposite in direction. A higher binding support order reduces father–child contact but may well raise “child quality”.

Life expectancy, fertility, and educational investment

In this study, we develop a model of overlapping generations where adults make decisions on consumption, fertility, and their personal education. We show that under the assumption of exogenous mortality, there are multiple steady states with club convergence occurring when mortality is sufficiently high. If mortality is sufficiently low, there will be a unique, stable steady state, and the economy will converge to a “good” steady state irrespective of where it starts from. Under the assumption of endogenous mortality with “threshold effects,” we find that club convergence will occur if the threshold is sufficiently high; conversely, a low threshold can help the economy to steer clear of the underdevelopment trap.     

Development challenges and opportunities confronting economies in transition

“Economies in Transition” (hereafter EIT or EITs) are countries in the process of shifting from “command” to “more open”, liberalized, free market economic systems. In addition to achieving major structural adjustments to their economies, the transformational process requires the introduction of a high degree of transparency in both the economic and political spheres of society. The transfer of state assets to private ownership is one part of the process as well, as is the creation or opening of “political space” that permits the emergence of private enterprise, multiparty political systems, and the introduction of a broad range of non-governmental organizations that carry out missions and functions which people themselves prefer to perform. Thus, the process of economic transformation requires a major socio-political-economic paradigm shift...one that places people and their needs at the center of the transformational process. The process is extremely difficult to achieve and is fraught with many dangers for countries that enter into it without substantial guidance from more economically advanced countries. This paper reports on the social development successes and failures of 31 economies in transition over the 15-year period 1990–2005. Included in the analysis are EITs located in East and South East Asia (N = 5), Central and Eastern Europe (N = 10), all 12 members of the Commonwealth of Independent States including the Russian Federation (N = 12), Turkey (N = 1), and the three Baltic States of Estonia, Latvia and Lithuania (N = 3). Using the author’s extensively pre-tested Weighted Index of Social Progress (WISP), the paper reports data at three levels of analysis: (1) WISP performances for all 31 EITs-as-a-group; (2) sub-regional performances on the WISP and its component sub-indexes for each of the six EIT sub-regions included in the analysis; and (3) country-specific performances on the WISP for each of the 31 countries included in the analysis. An earlier version of this paper was presented at the 2006 International Symposium and Lecture Series on Social Policy sponsored by the Chinese Academy of Social Sciences and held on the campus of Beijing Normal University, Beijing, China, 24–27 August, 2006.     

Fathers–participation in the domestic activities of everyday life

In this paper, the data from the multi-purpose survey on household “Time Use” conducted by Istat (the Italian National Statistical Institute) in 2002–2003 and the data from this same survey conducted in 1988–1989 will be analysed with the purpose of describing the fathers’ daily participation in the domestic activities and of highlighting the changes that have taken place during the 14 years elapsed between the two survey editions. The analysis will be carried out using standard time-use data analysis’ tool, time budget tables and by applying a multi-variate regression model with the objective of separating the relative contribution of the behavioural and structural factors to explain the variation observed.

Measurement of non-randomness in spatial distributions

Summary The measurement of departure from randomness in spatial distributions has widespread application in ecological work. Several “indices of non-randomness” are compared with regard to their dependence on sample number, sample size and density. Criteria for the best choice of index for specific situations are discussed. A new coefficientC _x is proposed for use with positively contagious distributions and tests of significance are given. WhenC _x and another index (S ²/m−1) are used for positive and negative contagion respectively, values ranging from −1 through 0 (random) to +1 are obtained, regardless of sample number, sample size or density.     

Population policy: Authoritarianism versus cooperation

The people whose interests are most adversely affected by frequent bearing and rearing of children are young women. Social changes that expand the decisional power of young women (such as expansion of female literacy, or enhancement of female employment opportunity) can, thus, be major forces in the direction of reducing fertility rates. This “cooperative” route seems to act more securely – and often much faster – than the use of “coercion” in reducing family size and birth rates. This essay examines the comparative evidence from India and China on this subject as well as the interregional contrasts within India. JEL classification: J11, J13, O15 Received August 20, 1996/Accepted November 14, 1996     

Legal Protections and Advocacy for Contingent or “Casual” Workers in the United States: A Case Study in Day Labor

Contingent, non-standard or “casual” work is present in large numbers in virtually every sector of the United States economy. Staffing strategies that use subcontracted or contingent work – strategies that once characterized only some low-wage workers such as garment and agriculture – have now spread to virtually every area of industry, including high tech and finance. United States law is a patchwork of provisions in separate federal statutes – and sometimes in each of the 50 states – governing whether a particular individual is an “employee.” Day laborers in the United States have particular challenging enforcing their limited rights. To address the issues of vulnerable low-wage workers being locked out of labor protections, activists have developed a number of strategies, including litigation and legislative campaigns. These strategies have more recently been broadened to facilitate developing leadership in a new social movement. In this article I draw a portrait of the day labor workforce from city- and state-based surveys of day laborers themselves. I then discuss strategies employed by day laborers to advance their workplace rights.

Childhood and Capability Deprivation in Germany: A Quantitative Analysis Using German Socio-Economic Panel Data

Child poverty has been widely discussed in Germany since the publication of the third official Poverty and Wealth Report of the German government in 2008 which—inter alia—focused on the situation of children and families. However, child poverty is not only caused by low household incomes and impacts of child poverty are not only restricted to financial consequences. The capability approach takes into account this multidimensionality of well-being and poverty of children. It conceptualizes human well-being as not only depending on financial means but also gives the same importance to the personal and social conversion factors which determine how far financial means can be converted into personal well-being. Before 2008 the capability approach had only been applied to the well-being of adults in Germany, but not specifically to the well-being of children. However, there are several reasons why a capability analysis for children will differ from a capability analysis for adults. Adults’ capability sets comprise dimensions that are less relevant for small children while other valuable capabilities have to be added. Furthermore the capability set depends to a large extent on the age of the child. The paper focuses on a multidimensional poverty analysis in the capability perspective of 5–6 years old children. In the domains of “Education/Leisure”, “Health”, “Social Participation” and “Income” child poverty is measured by predefined indicators. The relationship to the social and personal conversion factors of the caretakers is then evaluated. Additionally, a multidimensional poverty measure is analyzed.     

Life tables and population parameters of the green leafhopper,Nephotettix cincticeps (Uhler), in the southwestern district of Japan with special reference to the first generation on foxtail grass

Summary The three year (1988–1990) life tables ofNephotettix cincticeps were constructed, and the daily survival rate and longevity of female adults were estimated by Hokyo and Kiritani’s (1967) method for the overwintering and the first-generations on the foxtail grass in Okayama, southwestern Japan. The life tables and the population parameter values estimated were compared with those in the other generations on rice. The FARMCOP suction sampler was employed to survey the population density. The durations of pre-ovarial maturation of female adults of the 1st generation on foxtail grass and rice seedling were similar. Longevity of adults of the overwintering and the first generations which emerged on the wild host was longer than that of the other generations (2nd and 3rd generations) on the rice plants. Fecundity of females decreased successively as the generation proceeded and it became lowest in the final 3rd generation. Only about 3.5 percent of first-instar nymphs of the 1st generation emerged as adults in the fallow field. The survival rate of nymphs on foxtail grass was always lower in comparison with that on rice plants. However, the survival rates of nymphs on foxtail grass and rice seedling were not significantly different from each other under laboratory conditions. In the fields, senescence of foxtail grass occurred in the midst of nymphal period of the 1st generation. The survival rate of nymphs on foxtail grass decreased with the increasing in the nymphal density. Abundance of spiders during the 1st generation was higher than that in the early stage of rice plants.     

Critical factors for improving social sustainability of urban renewal projects

This study reviews the sustainable urban design concept and identifies critical factors for enhancing social sustainability of urban renewal projects. Through a questionnaire survey carried out in Hong Kong, the opinions of architects, planners, property development managers, and local citizens were sought and evaluated. The results derived from factor analysis indicated that certain design features should be incorporated for achieving social sustainability. “Satisfaction of Welfare Requirements”, “Conservation of Resources & the Surroundings”, “Creation of Harmonious Living Environment”, “Provisions Facilitating Daily Life Operations”, “Form of Development” and “Availability of Open Spaces” were believed to be the significant underlying factors for enhancing social sustainability of local urban renewal projects.

Fluctuations of grasshopper populations on aMiscanthus sinensis grassland

Summary Population densities of the three grasshopper species onMiscanthus sinensis grassland in the Kawatabi IBP Area, Japan,Parapleurus alliaceus, Mongolotettix japonicus andChorthippus latipennis, were estimated principally by the release-and-recapture method for five years from 1968 to 1972. The total number of individuals of all three grasshopper species was about 42 per 100m² in August. The number of individuals ofP. alliaceus adult, the dominant species on this grassland, showed a tendency to decline during the five years, though the amplitude was not so large. The number of eggs laid was, however, nearly constant and the mortality from the second nymphal instar to adult was relatively low and constant during the survey period. The weather conditions during the periods of egg and the first instar, such as snowfall and temperature decreasing, are suggested to be one of the factors causing variation in numbers. Contributions from JIBP-CT No. 145. A part of this study was supported by the special project, “Studies on the dynamic status of biosphere”, sponsored by the Ministry of Education.