Seasonality and vertical structure of light-attracted insect communities in a dipterocarp forest in Sarawak

Nocturnal flying insects were collected monthly for 13 months using ultra violet light-traps set at various vertical levels in a weakly-seasonal, tropical lowland dipterocarp forest in Sarawak, Malaysia. Abundance, faunal composition, size distribution and guild structure of these samples were analyzed with respect to temperal and vertical distributions. The nocturnal flying insect community in the canopy level was highly dominated by fig wasps (84%) in individual number, and by scarabaeid beetles (28%) in weight. A principal component analysis on monthly catches detected non-random, seasonal trends of insect abundance. The first two principal trends were an alternation of wetter (September to January) and less wet seasons (February to August) and an alternation between the least wet (January to March) and the other seasons. Many insect groups were less abundant in the least wet season than the other seasons, whilst inverse patterns were found in Scarabaeidae and Tenebrionidae. Significantly positive and negative correlations between monthly catch and rainfall were detected only in ovule-feeders and in phloem-feeders, respectively. Delayed, significant negative correlations between monthly catch and 1–3 month preceding rainfall were more frequently detected in phytophages, phloem-feeders, seed-feeders, wood-borers and scavengers. The peak in abundance along vertical levels were found at the canopy level (35 m) for phloem-, ovule-, seed-, root-, fungal-feeders and nectar collectors, at an upper subcanopy level (25 m) for scavengers and aquatic predators, and at a middle subcanopy level (17 m) for ants. Catches at the emergent level (45 m) did not exceed those at the canopy level.     

The conical structure of adjustive behavior

Wellbeing and coping have usually been treated as separate topics in previous research. The present study proposes a general framework for adjustive behavior which incorporates both previous topics as special cases. This framework shows definitional similarities and differences among wellbeing, coping and further special cases. Empirical data are presented which show a correspondence between the facets of the definitional system and the matrix of intercorrelations of the variables defined thereby. The correspondence is that of a conex, that is, the facets correspond to a conical coordinate system for the SSA space that reproduces the correlation matrix.The data were gathered as part of the Continuing Survey conducted jointly by the Israel Institute of Applied Social Research and the Hebrew University's Communications Institute. The population sampled is the adult urban and rural Jewish population of Israel, over 20 years of age in mid-December 1977. Interviews were conducted in the home through closed questionnaires, 27 of the items being of adjustive behavior.     

Temporal/spatial structure and the dynamical property of laboratory host-parasitoid systems

The effects of spatial structure in terms of local capacity, or the maximum number of larvae surviving competition at resource patches, and temporal structure in terms of the period vulnerable to parasitoid attack in host populations on the persistence of host-parasitoid systems were quantitatively evaluated by laboratory experiments and well-parameterized model analyses. One of two bruchid beetles,Callosobruchus maculatus andC. phaseoli, were used as a host with Heterospilus prosopidis used as the parasitoid.C. maculatus, in which few larvae survive competition to become adults in each bean, andC. phaseoli, in which many larvae become adults in each bean, along with two kinds of beans, the mung and the azuki, were combined to construct four (2×2) resource-herbivorous host-parasitoid systems that differed in local capacity and vulnerable period. The mung-C. maculatus system with the parasitoid was the most persistent, i.e., took the longest time for extinction of either the host or parasitoid to occur. Since this resource-herbivorous host combination exhibited the lowest local capacity and the shortest vulnerable period, these two conditions possibly promoted the persistence of the system. A model incorporating the host population structure supported the observed persistence. Furthermore, the possible contribution of the timing of density-dependent competition of the host on the host-parasitoid persistence is predicted.     

Family structure and and fertility behavior in Taiwan

The present analysis is based on the 1990 Taiwan Human Resources Survey to study the relationships between family structure, women's complete fertility and birth spacing. Imputed family size, as measured by either the ideal number of children expressed by a married woman or the number of actual surviving children whichever is larger, is used as a proxy of a woman's complete fertility. The results indicate a majority of married couples in Taiwan begin married life living with the husband's parents and later move out to establish a nuclear unit. This limited experience in the extended family exerts an upward pressure on imputed family size even when other relevant variables are statistically controlled. Further, the effect of living with the husband's parents on shorter duration of birth spacing is only limited to the time when the parents provide free child- care for married couples.     

Interspecific relations in forest floor coleopteron assemblages: Niche overlap and guild structure

Summary In six different environments of the Towada-Hachimantai National Park, the forest floor coleopterons were sampled by means of pitfall traps with five different baits. Their niche breadths and niche overlaps were assessed for the electivity of habitat, bait, and habitat × bait, and compared with those expected from neutral models constructed randomly. The niche breadths in the observed assemblages were smaller than those expected from the neutral model, while the niche overlaps were more widely distributed than those expected from the neutral model. Mean overlaps between species neighbors in niche space, cluster analyses, and ordinations of species revealed a guild for habitat, bait and habitat × bait. Lawlor’s (1979) gamma matrices concerning the habitat electivity show that the rates of mutualism resulted from indirect interspecific competitions are significantly smaller in the guild than in the whole assemblage. This suggests that the interspecific competition among the guild members is mitigated or even converted into mutualism by joining of the species which do not belong to the guild. The rates of mutualism were also significantly larger in the resource state of two dimensions (habitat × bait) than in that of either one. Therefore, if niche overlaps are measured on the basis of resource state of multi-dimensions, the rates of mutualism may increase further.     

Endogenous fertility,altruistic behavior across generations,and social security systems

The present paper explores the impact of an intergenerational externality on private fertility decisions, under a pay-as-you-go social security system. The analysis is performed in the framework of a steady state growth model, with overlapping generations. To explain why households have children, altruism between parents and children is assumed. Surprisingly, the effects of altruism are not symmetric. The private fertility decisions are optimal only if children love their parents, because children then make private transfers at exactly the right level.Comments of participants of a seminar on economic theory of Prof. K. Jaeger at Free University of Berlin at July 20, 1989, are gratefully acknowledged. I am indebted to Alessandro Cigno, Frank Klanberg and Elmar Wolfstetter for many helpful suggestions.     

Impact of developmental variance on behavior of models for insect populations I. Models for populations with unrestricted growth

Summary The concept of developmental variance is discussed with reference to its use in models for insect populations. When included in a model, developmental variance is typically used to describe the variation of developmental periods among individuals. However, its presence in a model can also have indirect impact on survival and fertility schedules. This impact can lead to significant changes in population growth rates and generation times. These relationships between developmental variance and population growth in models are quantified and discussed.     

Stability of environment and of insect populations

Summary The abundance of moths was monitored with light-traps in two sites in southern Bohemia, České Budějovice for 22 years and in Černiš for 9 years. In these sites, that are vastly different in environmental stability and predictability, stability of insect populations was studied. The amplitude of fluctuations in abundance of the insect populations, as measured by the coefficient of variation (CV), varied a great deal between species so that there was a large overlap between the two sites. Nevertheless there was a highly significant tendency for species at Černiš, the more stable site, to have smaller values of CV, i.e., to be less fluctuating. Also in species co-occurring in the two sites, the CV at Černiš tended to be smaller. Trends in abundance of individual species over time, both increases and decreases, were common in both sites and did not differ between habitats. Environmental stability begets insect population stability in terms of the amplitude of the fluctuations, but trends in time occur irrespective of stability of the habitat.     

Impact of developmental variance on behavior of models for insect populations II. Models for populations with density dependent restrictions on growth

Summary The impact of variation in developmental times on behavior of models for insect populations is investigated with special reference to models which include various types of intraspecific competition. At low densities, increases in developmental variation led to decreases in reproductive rate. At high densities, increases in developmental variation led to increases in reproductive rate. There was little change in the relationship between developmental variance and generation time as density increased.     

The structure and significance of community satisfaction

Residential and community satisfaction have been studied for many decades in an effort to understand human commitments to local places. In more recent years, concepts that more nearly reflect commitment have been developed, among them place attachment. Yet, the extensive, prior work on empirical indicators of satisfaction give that concept a particularly useful entry into studies of experiences of place, even though these may only provide estimates of phenomena of deeper commitment. The present study is drawn from the data for a large-scale investigation of the meaning ofcommunity in metropolitan America. Based on 2,622 women and men from 42 municipalities in 10 SMSAs across the United States, the study includes a sample of all socioeconomic statuses and from minority as well as majority populations. On the basis of factor analyses of a wide array of evaluations and satisfactions with housing, neighborhood, and the wider community, a structure for community satisfaction has been delineated. On the basis of these community satisfaction factors, along with several other social role and personality variables, an estimate is provided of the personal significance of community satisfaction in people's lives, using life satisfaction as the dependent variable. While there are socioeconomic status and other variations, community satisfactions appear to be important influences on life satisfaction at all socioeconomic status levels.Requests for reprints should be addressed to Marc Fried, Dept. of Psychology, Boston College, Chestnut Hill, MA 02167.The now defunct Center for Metropolitan Studies of the National Institute of Mental Health was most helpful, not only in funding this study but in many other respects as well. The author is also grateful to the many people who participated in the large-scale study of which this paper represents only a small part. In particular, John Havens and Lorna Ferguson were most important to the achieving of the objectives of the study.     

The association of television and radio with reproductive behavior

This note analyzes the association between media exposure and reproductive behavior in 48 developing countries. A summary of part of a more extensive Demographic and Health Surveys report, it shows strong connections between media exposure and the use of modern contraception, the number of children desired, and recent fertility. Television viewing is particularly important; it is assumed to expose viewers to aspects of modern life that compete with traditional attitudes toward the family and is associated with greater use of modern contraceptive methods, with a desire for fewer children, and with lower fertility. These relationships are particularly noteworthy because the data measure only the frequency of media exposure with no information about its content.     

The dynamics of immigrant welfare and labor market behavior

This paper analyzes transitions into and out of social assistance, unemployment, and employment. We estimate a dynamic multinomial logit model, controlling for endogenous initial condition and unobserved heterogeneity, using a large representative Swedish panel data set. The empirical results suggest that particularly refugee immigrants display a greater degree of “structural” state dependence than natives. The high welfare participation rates among refugee immigrants may be due to the existence of a “welfare trap”, while participation among natives and non-refugee immigrants is largely due to permanent unobserved characteristics. These results suggest that welfare reforms may have differential effects on refugee immigrants and natives.

Demarcating forest, containing disease: land and HIV/AIDS in southern Zambia

The ongoing HIV/AIDS pandemic in southern Africa continues to manifest itself in unexpected ways. While the consequences of the disease appear straightforward in some aspects—e.g., medical, labor, cost—in other respects the repercussions, while large, are nonetheless highly nuanced and can be counterintuitive. This paper reports on the intersection of HIV/AIDS, migration, livelihood adaptation, land tenure, and forest conservation, to outline how adaptation to the pandemic has reworked significant aspects of land tenure to result in increased forest conservation in southern Zambia in the near to medium-term. The research uses a combination of ethnography, case studies, household survey and spatial analyses and finds that HIV/AIDS is used in customary legal settings to enhance land access. We also draw links to practical and theoretical implications of the relationship between HIV/AIDS, land tenure, and deforestation in Sub-Saharan Africa.     

The screw-worm flyChrysomya bezziana villeneuve (Diptera: Calliphoridae) in a sterile insect release trial in Papua New Guinea

Summary The feasibility of the sterile insect release method (SIRM) was tested against natural populations of the Old World screw-worm fly,Chrysomya bezziana in the Musa Valley, Papua New Guinea. Sterile mating frequencies were determined from egg masses laid by native females on wounded, sentinel cattle. The aerial release of sterilised puparia resulted in low frequencies of sterile matings and few trap recaptures of released material. The release of chilled adult flies resulted in higher frequencies of sterile matings and many trap recaptures. The mean density of males released was 230 males per km² per week over a target area of 361 km² (48% of the valley). Sterile masses were first detected 2 weeks after the release of chill flies commenced, reaching a weekly peak of 33% after 5 weeks of releases with 15% of egg masses found to be sterile during the final month. The levels of sterile matings achieved in this trial were similar to comparable SIRM studies made in the USA, Mexico and Guatemala to control the New World screw-worm fly,Cochliomyia hominivorax.     

The savings behavior of temporary and permanent migrants in Germany

This paper examines the relative savings position of migrant households in West Germany paying particular attention to differences between temporary and permanent migrants. Our findings reveal significant differences in the savings rates between German natives and immigrants. If remittances are treated as savings, however, migrants who intend to return to their home country save significantly more than comparable natives. The results of a decomposition analysis indicate that slightly more than half of the differences in the savings rate between Germans and permanent migrants and almost 70% between temporary and permanent migrants can be attributed to differences in observable characteristics.     

The theoretical and empirical structure of general well-being

A comprehensive set of variables that have been supported as contributing to overall health and general well-being were analyzed to determine their simple structure using factor analysis and their relative contribution using Pearson correlation. The contributors to general well-being had been theoretically grouped into: emotions, beliefs, temperaments, behaviors, sittuations, experiences and health. The empirical factor structure was compared with the theoretical structure used to develop the variables. Stability was investigated by comparing results with those of another geographically separated group. All subjects were normally functioning working adults. The results demonstrated the feasibility and potential usefulness of using self-report questionnaires with multivariate procedures to measure components of the global general well-being concept.     

The evolution of homoerotic behavior in humans

This paper presents a theoretical model for the evolution of same-sex sexual behavior, or homoerotic behavior, in humans. Contrary to the traditional study of the topic, the emphasis is on homoerotic behavior itself, irrespective of sexual orientation. It is an inferential model drawn from cross-species evidence, cross-cultural evidence, and current evolutionary theory. It is posited that humans evolved a disposition for homoerotic behavior because it increased same-sex affiliation among peripheralized hominids and indirectly influenced rates of survival and reproductive success. The implications for the conceptualization of same-sex sexual behavior and future research are indicated.     

The long-term effects of time-dependent maternity behavior

Using the integral population model of Sharpe and Lotka, it is demonstrated that if the time variation of the maternity function is assumed to only affect the parent population, then standard methods of obtaining the long-term behavior may still be used. Further, if the net maternity function has explicit time dependence, in contrast to age dependence, only for time less than the minimum age of childbearing, the standard techniques still may be used. It is shown that the recent extensions of Cerone and Keane to include exponential time dependence may be applied, together with the above observations, to define piecewise time-dependent net maternity functions and to determine the resulting long-term asymptotic behavior of the population. The population management problem of determining the time path of change needed to approach a given population also is considered in some detail.