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.     

Distribution ofMogannia minutamatsumura (Homoptera: Cicadidae) in the Island of Okinawa: Expansion of distribution range during five years

Summary A five-year study on the microgeographical distribution pattern of a sugarcane cicada,Mogannia minuta (=iwasakii), in the Island of Okinawa revealed that the trapezoid type distribution was an unique feature of the distribution of this species. The rate of expansion of the distribution range was remarkably small despite the continuous occurrence of sugarcane plants. These facts can be explained well by the theory of escape. That is, the epidemic cicada populations should be free from predation pressure in the infested area, but those in peripheral zones could be eradicated by predators. The possible role of regulatory factor(s) which suppress further increase in the density in the infested area was suggested.     

A field experiment on dispersal of newly emerged adults ofMonochamus alternatus (Coleoptera: Cerambycidae)

Summary Newly-emerged adults ofMonochamus alternatus aged 1 to 5 days were code-numbered with lacquer paint and released by placing them on the trunks of one or two trees in aPinus thunbergii stand at weekly intervals during the beetle emergence period from 1980 to 1983. Beetles were captured at weekly intervals from one week after the first day of release. Determinations were made on the distance and direction of beetle dispersal during a week after release and analysed by a method of Inoue (1978). When the stand canopy was closed, the rate of beetle’s stay on trees was 0.56 per week. The beetles dispersed at random by walk and flight. When the pine stand was sparse, the rate of beetle’s stay on trees was 0.02–0.30 per week. They dispersed at random by flight. The average distances traversed were estimated to be 7.1–37.8 m for the first week after emergence. Using other method, the average distance traversed was estimated to be 10–20 m for each week through the first 3 weeks after release. The results of stepwise multiple regression analysis and a simple field experiment suggested that the dispersal of newly-emerged beetles was affected by stand density, number of beetles emerging from individual dead trees, maximum air temperature, and precipitation.     

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.     

Anopheles subpictus Grassi: Observations on survivorship and population size using mark-release-recapture and dissection methods

Summary A mark-release-recapture experiment to estimate population survivorship and absolute size was performed with wild-caughtAn. subpictus adults at the village of Khano-Harni, Lahore District, Punjab Province, Pakistan during September 1978, the end of the monsoon rainy season, when temporal population abundance was maximized. Daily survival rate estimated from the recapture sequence of marked adults was low, males=0.192 and females=0.343. Survivorship for females estimated by several vertical age-grading procedures ranged from 0.347 to 0.628. Both stage- and age-specific life tables were calculated from vertical age-grading data determined by the dilatation method. Female and male population size was estimated byBailey’s modification of theLincoln Index and was found to average 4478.4 and 6106.8, respectively. The bionomics, survivorship and population size ofAn. subpictus in the Lahore are indicated that this species was probably not important in the transmission of human malaria.     

Health Condition and Quality of Life in Older Adults: Adaptation of Qolie-89

This study aimed at adapting the Questionnaire Quality of Life in Epilepsy (QOLIE-89 version 1.0: Vickrey et al., 1993), Quality of Life in Epilepsy QoLIE-89 RAND (Santa Monica, CA)] so that it may be used to measure quality of life (QoL) of older adults, healthy or suffering from various chronic illnesses. The participants were 202 older adults recruited from the Pathology Clinic of a general hospital in Thessaloniki, Greece, and from Community Centers for Older adults. The mean age was 71 years. Of them, 51 suffered from diabetes, 50 from cardiovascular disease, 52 suffered from arthritis/myoskeletal diseases, and 49 were healthy. The QOLIE-89 inventory comprises 89 items that measure 17 topics. Exploratory factor analysis revealed 3 factors, namely, health (i.e., physical health and functioning), cognition, and social behavior. Cronbach’s α for the various topics in each group of participants ranged from 0.60 to 0.90 with a number of exceptions with very low α. Concurrent validity was tested through correlations with measures of subjective well being, affect, life satisfaction, and adaptation to old age. A series of ANOVAs showed differences between the healthy and the chronic illness groups of participants but no clearcut differences between the three chronic illness groups. Further study on the adaptation of QOLIE-89 is needed so that its potential as a general measure of QoL in older adults is determined.     

Life table analysis of the green rice leafhopper,Nephotettix virescens (distant) (Hemiptera: Cicadellidae), and efficient vector of rice tungro disease in asynchronous rice fields in Indonesia

Summary Population dynamics ofNephotettix virescens was studied in 17 paddy fields transplanted at intervals of about 1 month in 1988–1990. The adult density was highest either in the immigrant or the 1st generation and sharply decreased to the 2nd generation. The survival rate of the 1st generation was lowest in the transition season when areal population density increased. Key factor analysis revealed that the nymphal and adult mortality of the 1st generation (kn) was the principal source of population fluctuations. No significant correaltion was found between kn and natural enemy density, natural enemy density/healthy egg density, or the precipitation during the nymphal period. On these bases adult emigration was suspected to be the key factor. Areal population build-up ofN. virescens in the transition season was considered to occur as a result of increasing immigration to young stages of rice. Contribution from Indonesia-Japan Joint Program on Food Crop Protection (ATA 162), which was implemented by the Directorate of Food Crop Protection, Ministry of Agriculture, Indonesia and Japan International Cooperation Agency, Japan.     

The Capability Approach and Fuzzy Poverty Measures: An Application to the South African Context

One way of making the capability approach (CA) operational uses fuzzy poverty measures. In this paper, we present a new approach to applying these measures in the South African context using responses to a questionnaire on ‘The Essentials of Life’ in conjunction with a methodology for dealing with the vagueness of poverty. Our results suggest very low cut-offs for people or households to classify as definitely poor for some social indicators. These cut-offs are far lower than those Klasen used in his application of the CA. The attempt to apply the CA using Cheli and Lemmi’s ‘totally fuzzy and relative’ poverty measure in conjunction with our approach to specifying cut-offs can lead to incoherence. This measure can, nonetheless, be useful when social indicators have a ‘relativist component’. While the Cerioli and Zani measure does not lead to such incoherence, it also has a serious weakness.     

Oviposition site selection and avoidance of additional mating by females of the dragonfly,Cordulia aenea amurensis Selys (Corduliidae)

Summary Females of an odonate species in which oviposition sites overlap with mating sites may adopt one or more of the following strategies when they lay eggs except when they ‘trade’ mating for access to suitable oviposition sites or for services (guarding, etc.) provided by males: (1) ovipositing at hidden places; (2) ovipositing at a time when males are neither patrolling nor watching; (3) indicating non-receptivity by a behavioral display. The density of ovipositing females of the dragonfly,Cordulia aenea amurensis Selys which was studied between 1970 and 1983 at a pond (H?rai-numa, Sapporo, Hokkaido) had a high negative correlation with the distance from ‘entrance’ (a part of shore at which the arrival of most adults seems to have occurred). On the other hand, oviposition was rarely observed at a sector being distant from entrance in spite of the inference that larval survivorship was probably high at this sector. Most females oviposited among emergent vegetation in which approach of males to them was difficult, and they scarcely traveled across the open water in search of oviposition sites. Therefore, most females of the population studied were considered to adopt the first strategy. The second and third strategy were not adopted by the population studied. Finally, the influences of some environmental factors and traits possessed by a species on the adoption of these tactics or on the execution of the ‘trades’ were discussed. Ecological studies ofCordulia aenea amurensis Selys, VII. This work was supported in part by a Grant-in-Aid for Special Project Research on Biological Aspects of Optimal Strategy and Social Structure from the Japan Ministry of Education, Science and Culture.     

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.     

The Effect of Urbanization on China’s Fertility

The relationship between urbanization and fertility decline is known to be inverse in developed countries. However, the nature of this relationship in developing countries that already have relatively low fertilities is not well-understood. This study aims to illustrate how much urbanization contributed to China’s fertility decline between 1982 and 2008 and forecasts how much it can contribute to future reductions in fertility. The study examines changes in the total fertility rate (TFR) at both the national and provincial levels, given regional differences in the urbanization rate. The results show that changes in rural fertility behavior accounted for most of the decline in the national TFR between 1982 and 2008. This finding suggests that official birth control policies were instrumental in curbing China’s population growth. However, urbanization was responsible for about 22% of the decrease in TFR during this period, and its effect was especially important during the latter years (2001–2008). In most provinces, urbanization associated with a decline in provincial-level fertility. The forecasts indicate that urbanization will become the primary factor behind future declines in national fertility. Given the negative effect of urbanization on the TFR, it is possible to relax the one-child policy without having adverse implications for population growth.     

Population studies ofCavelerius saccharivorus Okajima (Heteroptera: Lygaeidae): Adult dispersal in relation to the density

Summary Two adjacent stations (H and L) were set up to study movement ofC. saccharivorus adults in sugarcane fields. At the beginning of the study the density ofC. saccharivorus including all stages of development was quite different between the two. The density of the first generation adult on Station H was about 5 times that on Station L. The number ofC. saccharivorus on both the stations became almost the same one month after the beginning of the study. At the beginning of the study macropterous adults were more numerous in Station H than in Station L. However percentage of macropterous adults on Station L increased after one month whereas that on Station H declined. About 2,000 marked adults were released on each station during the early period of the emergence of the first generation adult. Marked insects were recaptured on both the stations one month after the release. The adults released on the dense population (H) tended to disperse more actively than those on the scarce population (L). Marked macropterous adults moved more actively than brachypterous ones. The density related dispersal of adults was considered to be an important factor to regulate the population density.     

Genetic variation of density responses in relation to wing polymorphism in the oriental chinch bug,Cavelerius saccharivorus Okajima (Heteroptera: Lygaeidae)

Summary Responses to nymphal density in the determination of wing form were compared between the offspring from brachypter x brachypter crosses and those from macropter x macropter crosses of the oriental chinch bug,Cavelerius saccharivorus. In the offspring from crosses between macropters, there was a strong tendency for macropters to increase to a rather high level with increasing nymphal density in both sexes. In contrast to this, in the offspring from crosses between brachypters, the appearance rate of macropters attained a maximum value in moderately crowded conditions and conversely decreased to a lower level in more crowded conditions in both sexes. Thus density response patterns concerning the determination of wing form were quite different between the offspring from different crosses in the wing form, indicating that there is a genetic basis underlying wing polymorphism in this species. As for the body size of emerged adults, macropters tended to be larger than brachypters in the same crowded condition. Moreover, the rate of decrease of body size with nymphal density was lower in the offspring from crosses between macropters than in the offspring from crosses between brachypters. This indicated that the former offspring are more tolerant of nymphal crowding than the latter. The difference in such a tolerance against nymphal crowding between the offspring from different crosses was considered to be related to the difference in the appearance of macropters in the crowded conditions between them.     

Biology ofHyphantria cuneaDrury (Lepidoptera: arctiidae) in Japan. V. Preliminary life tables and mortality data in urban areas

Summary Studies on the population dynamics of the fall webworm,Hyphantria cunea have been carried out at three survey stations and along selected roads in the urban area of Tokyo since 1966. Twelve survivorship curves obtained during two years and 8 life tables show that the mortality rate in early developmental stages of the fall webworm is remarkably low as compared with that of other lepidopterous defoliaters and the mortality rate in later developmental stages is compensatory high. The low mortality rate in early stages is considered to be due to the protective role of the nest-web and the lack of egg and larval parasites. All but one parasitic species emerge from prepupae and pupae. Spiders living in the nest-web of the fall webworm play an important role in reducing the number of young larvae. Direct observations and caging experiments showed that relatively high mortality during later larval stages is mainly due to predation by birds (in the first generation) and wasps (in the second generation). The generation mortality in the survey stations always exceeded the level where the population is kept at the steady state, and the outbreak of this moth is considered to be continued by the immigration of adults from large trees growing in gardens on which the larvae can escape from predation pressure. Contributions from JIBP-PT No. 51. A part of this study was supported by the special project research, ‘Studies on the dynamic status of biosphere’, sponsored by the Ministry of Education.     

Assessing Subjective Well-being in Chinese Older Adults: The Chinese Aging Well Profile

Subjective well-being has increasingly been used as a key indicator of quality of life in older people. Existing evidence shows that it is likely that eastern cultures carry different life values and so the Chinese Aging Well Profile was devised for measuring subjective well-being in Chinese adults (50+). Data was collected from 1,906 community-dwelling Chinese (50+) in Taiwan in six sequential stages, involving qualitative interviews and psychometric testing. Seven key dimensions of subjective well-being identified in the interviews provided an item bank for instrument construction. The 31-item Chinese Aging Well Profile comprised seven subscales–’physical’, ‘psychological’, ‘independence’, ‘learning & growth’, ‘material’, ‘environmental’, and ‘social’ well-being. The study indicated that elements of subjective well-being are common across western and eastern cultures but are interpreted and weighted differently. This new instrument has demonstrated preliminary evidence for reliability and validity and that it is suitable for use in the Chinese speaking older population.     

Predation ofCyrtorhinus lividipennis Reuter on eggs of the green leafhopper and brown planthopper in rice

Summary The functional response ofCyrtorhinus lividipennis feeding on brown planthopper (BPH) and green leafhopper (GLH) eggs was found to be Holling’s Type II. The Random Predator Equation fitted the data satisfactorily. Using Manly’s preference index, α, both the male and femaleC. lividipennis were found to prefer BPH eggs. There was, however, no evidence of switching and the ratio of the respective searching efficiencies could account for the preference.     

Changes in the quality of life of Durban’s people

Durban, the busiest port and second largest industrial hub in South Africa, has a developmental vision that sees its residents living in ‚acceptably serviced housing’ and enjoying a ‚generally high quality of life that can be sustained’. This vision is in response to South Africa’s transitional aspirations to move from an inequitable apartheid state to a democratic society with greater socio-economic parity. Since 1998 the eThekwini Municipality, which is the local authority responsible for the city of Durban, has conducted annual surveys to monitor the changes in the quality of life of Durban’s people. Structured questionnaire interviews were administered in 14 300 dwellings between 1998 and 2005. The samples drawn each year were representative of the city’s demographics and covered a wide range of housing types. Results indicate that parity of life satisfaction between race groups is as far apart in 2005 as it was in 1998. The paper undertakes trend analysis, from a local government perspective, of key objective and subjective variables in the surveys. It identifies the domains that have the greatest impact on satisfaction with life, and reports the salient issues for black householders, who have the lowest level of life satisfaction.The Research Locale:  Durban, which is a port city on the east coast of South Africa, has a population of over 3 million people. The population is comprised of the following groups: Asian (20%), black (68%), coloured (3%) and white (9%). It is Africa’s busiest port and is South Africa’s second largest industrial hub. It provides key trade linkages to Johannesburg, which is South Africa’s largest industrial hub. The major economic sectors are manufacturing, tourism, finance and transport. The complex topography is intersected by 19 rivers that flow to 98 kms of coastline.     

Individual quality of life: can it be accounted for by psychological or subjective well-being?

There is ongoing discussion in the scientific literature about the need for a more theoretical foundation to underpin quality of life (QoL) measurement. This paper applied Keyes et al.’s [J. Pers. Soc. Psychol. 82 (2002) 1007] model of well-being as a framework to assess whether respondents (n = 136 students) focus on elements of subjective well-being (SWB), such as satisfaction and happiness, or on elements of psychological well-being (PWB), such as meaning and personal growth, when making individual QoL (IQoL) judgments using the Schedue of the Evaluation of Individual Quality of Life (SEIQoL). The Keyes et al.’s model was confirmed and explained 41% of the variance in SEIQoL scores. Both SWB and PWB were correlated with the SEIQoL Index Score and SWB was found to be an important mediating variable in the relationship between PWB and SEIQoL. When analyzing different well-being combinations, respondents with high SWB/high PWB had significantly higher SEIQoL scores than did those with low SWB/low PWB. Respondents with high PWB/high SWB had higher SEIQoL scores than did those with high PWB/low SWB. Longitudinal studies in different patient groups are needed to explore the dynamic relationship between IQoL and well-being. Further investigation of the relationship between PWB and SWB with other instruments purporting to measure QoL would contribute to an enhanced understanding of the underlying nature of QoL.     

Distribution patterns of and sampling plans forTetranychus urticae Koch (Acarina: Tetranychidae) on roses

Summary I sampledTetranychus urticae Koch (Acarina: Tetranychidae) regularly from four rose gardens in Kyoto and Nara Prefectures in 1988–1990. When mite density was low,T. urticae showed an uneven vertical distribution, being more abundant in the lower third and absent from the upper third of the plants. Mite density was less variable within than between plants, suggesting that a sampling plan which includes more leaves from different plants rather than from different levels of a plant is favourable. Spatial distribution ofT. urticae was nonrandom and followed the negative binomial distribution. In addition, both the Taylor’s power law and the Iwao’s patchiness regression described the distribution well. An empty-sample method for estimating mite density from the proportion of empty sampling units was developed. Sampling plans for determining the sample size required to reach a predetermined precision level, based on this method and by directly counting the mites, were designed. The counting method was more accurate than the empty-sample method. However, when the time factor was taken into account, the latter was more favourable, because it was faster than the former at a density range of 1.5–300 mites leaf⁻¹, which was most commonly encountered in the field.