The dynamics of laboratory populations ofCallosobruchus chinensis andC. Maculatus (Coleoptera: Bruchidae) in patchy environments

Summary Experiments are described showing the long-term dynamics of two species of bruchid beetles (Callosobruchus chinensis andC. maculatus) in arenas in which the resource of 50 black-eyed beans is divided between 5, 10 or 50 ‘patches’. Both species of adult beetles exhibit clumped distributions between patches. Within a patch there is a tendency for a density dependent reduction in (1) eggs laid per female, (2) the proportion of eggs hatching per bean (C. chinensis only) and (3) larval survival which is strongly overcompensating (particularly inC. maculatus). A discrete generation model is used as a framework to draw these results together and show how the different factors affecting natality and mortality can influence the population dynamics. Finally, the importance of the resource renewal interval in influencing the period of the population cycles is discussed.     

Receptivity of female remating and sperm number in the sperm storage organ in the bean bug,Riptortus clavatus (Heteroptera: Alydidae)

This study examines the relationship between the number of sperm in the seminal receptacle (spermatheca) and the receptivity of female remating in the bean bugRiptortus clavatus Thunberg. On the 21 st day after the first mating when receptivity to remating was > 70%, females receptive to remating had significantly fewer sperm ( < 40 on average) in the spermathecae than females reluctant to do (about 150 on average). However, averages of the number of eggs laid by receptive and reluctant females within 21 days were almost same. The proportion of fertilized eggs for receptive females at 15–21 days after copulation was significantly lower than that for reluctant females. Spermatozoa transferred from a male to a female’s spermatheca were detected 5 min after copulation and then increased continuously to about 500 with the first hour. When copulation durations were manipulated artificially, the shorter the copulation period (=females had less sperm in their spermathecae), the higher the remating rate became. Females may perceive the number of sperm in their seminal receptacles and then determine whether they copulate or not. These results support the hypothesis that females mate multiply in order to replenish inadequate sperm supplies to fertilize all eggs produced.     

Contagious egg-distribution on host pods and avoidance of pods received eggs in a wild bruchidKytorhinus sharpianus

Summary The present study investigated the way a wild bruchid,Kytorhinus sharpianus, distributes its eggs on host pods. First, we counted the number of eggs per pod on the host plant (Sophola flavescens) in the field. The egg-distributions by the overwintered-generation adults in July and by the second-generation adults in mid October did not deviate from Poisson distribution because of small numbers of eggs laid. However, the egg-distribution in late August when many first-generation adults emerged was significantly contagious. The deposition of eggs was determined for three types of pods: (A) clean pods, (B) pods with eggs, and (C) those which eggs had been laid on but were removed from later. The numbers of eggs laid newly on three types of pods were significantly different; A>C>B, suggesting that an oviposition marker pheromone (O.M.P.) caused females to avoid pods on which eggs were deposited. Egg-shells reinforced that response. Monte Carlo simulations for the egg-distribution on pods predicted that even if females avoid pods with heavy egg-load through O.M.P., the egg-distribution becomes contagious when there is a large heterogeneity in quality of the pods.     

Longevity, flight ability and reproductive performance of the diamondback moth,Plutella xylostella (L.) (Lepidoptera: Yponomeutidae), related to adult body size

Plutella xylostella in the temperate zone shows a clear seasonal change in adult body size. In the laboratory, large and small moths were produced during immature stages at 15°C and 25°C, respectively. These moths were then used to evaluate longevity, age-specific flight ability, flight ability of mated and unmated females, and the influence of flight experience on the subsequent reproductive success. The large moths lived longer and displayed a greater flight ability over 3 weeks. Irrespective of body size, unmated females flew for a longer time than mated females, and flight experience affected their subsequent reproductive success. Females of both sizes mated and laid eggs soon after emergence, without any obvious pre-reproductive period. More flight experience did not delay oviposition, but did reduce egg production. It is likely that large moths with a longer adult life span and greater flight ability are better fitted for long-distance flight and more fecund than small ones. These experimental results may explain why long-distance migration ofP. xylostella is mostly seen during cool seasons, when relatively large moths with long forewing appear in the field.     

Reproduction and egg diapause of the oriental chinch bug,Cavelerius saccharivorus okajima (Heteroptera: Lygaeidae), in the subtropical winter season in relation to its wing polymorphism

Summary Reproduction and egg diapause of the oriental chinch bug,Cavelerius saccharivorus, in the subtropical winter season were investigated in relation to its wing polymorphism. Macropterous females collected from the southern part of Okinawa Is. in the autumn season delayed their oviposition and were less fecund early in the adult life period, but survived much longer than brachypterous females collected from the same locality. The total fecundity was not significantly different between wing morphs. The diapause of eggs laid by brachypters tended to be terminated more easily at a high temperature than that of eggs laid by macropters. This indicated that the eggs laid by macropters were more intense in their diapause than those laid by brachypters. However, irrespective of the parental wing form, diapause showed considerable variation in its intensity within and between clutches.     

International Well-being Index: The Austrian Version

The International Well-being Index (IWI) measures both personal and national well-being. It comprises two subscales: the Personal Well-being Index (PWI) and the National Well-being Index (NWI). The aim of this paper is to test the psychometric properties (validity and reliability) of the translated scale in Austria. Convergent validity is assessed using the Scales of Psychological Well-Being, the Satisfaction with Life Scale and the Positive and Negative Affect Scale. In addition, a Visual–Analog Scales capturing “satisfaction with life as a whole” was applied. The participants were 581 students of the Medical University Innsbruck (female: 47.7%; age: 23.2 ± 3.7). Internal consistency (Cronbach’s α) of the IWI was for both scales > .70 (PWI: .85; NWI: .83). The exploratory factor analysis of the IWI identified a 2-factor-structure identical with the two scales of the IWI explaining 54.2% of the variance. The convergent validity hypotheses were confirmed, construct validity was partly confirmed for the PWI being a deconstruction of a first factor called “satisfaction with life” (38.1% explained variance). Happy participants scored higher on the PWI (84.3 ± 7.9 vs. 68.7 ± 13.7; p < .001) and NWI (64.3 ±  15.8 vs. 57.9 ±  15.1; p < .001) scores than unhappy participants. It is concluded that the Austrian version of the IWI is a reliable and valid instrument to assess personal and national well-being. Further studies including a representative sample should be carried out on a recurring basis to use the IWI as an indicator for social science research in Austria.     

Body Image and Quality of Life in a Group of African American Women

African American (AA) women’s preference for a larger body size and underestimation of their body weight may affect the relationship between their body weight and weight-related quality of life (QOL). We wanted to examine the relationship between weight-related QOL and body mass index (BMI) in a sample of overweight AA women. Thirty-three overweight AA women completed a clinic visit to measure height, weight, and complete surveys including the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) and the Stunkard Figure Rating Scale. BMI was calculated using measured height and weight. Correlations and linear regression models were estimated using SAS v 9.1. In this sample, the mean total quality of life score was 78.00 ± 17.68 on a 100 point scale. There was a modest correlation between BMI and total weight-related QOL (r = −0.034, p = 0.053). Body image dissatisfaction was the strongest predictor of total quality of life score (p = 0.04). African American women’s unique cultural perception of body image may play a key role in weight-related QOL.     

Host plant conspicuousness and the distribution of eggs and larvae in the butterfly,Anthocharis scolymus (Lepidoptera: Pieridae)

Summary We investigated how the distribution pattern of eggs and larval on the host plant,Turritus glabra, was influenced by the oviposition behavior of the pierid butterflyAnthocharis scolymus. Females searched for the host plants visually and they frequently approached taller host plants with sparse surrounding vegetation. After encountering host plants, oviposition behavior of females was independent of host plant characteristics such as height, density, and type of surrounding vegetation. A female laid eggs singly on a host plants. Most females appeared to lay their eggs regardless of the presense of eggs on the host plant. Consequently egg and larva tended to be abundant on conspicuous host plants as measured by height or relative isolation from other plants. However, overcrowding of eggs on an individual host decreased the survival rate of larvae.     

The Performance of the World Health Organization’s WHOQOL-BREF in Assessing the Quality of Life of Thai College Students

The purpose of this study was to examine the performance of the Thai-version of WHOQOL-BREF in assessing the quality of life (QoL) among Thai college students. The psychometric properties of WHOQOL-BREF were assessed in this study. The self-administered WHOQOL-BREF questionnaire was applied. A total of 407 Thai college students (male age = 20.5 ± 1.2; female age = 20.5 ± 1.2) participated in this study. Item-response distributions, internal consistency reliability, discriminant validity, criterion-related validity and construct validity through confirmatory analysis were analyzed. The findings indicate that the WHOQOL-BREF had acceptable internal consistency (α = 0.73–0.83 across four domains), all items highly correlated with corresponding domain scores (r = 0.53–0.80), the indices of a two-order confirmatory factor analysis (CFA) demonstrate that the data fit the model well with allowing covary of error variances of some items, all items had good property of criterion-related validity and item discrimination and, all three domain scores except the social relationship domain had significant associations with overall QoL or general health. The results suggest that the WHOQOL-BREF was reliable and valid to health professionals in the assessment of the QoL of college-based Thai youth, but some unsuitable items may be deleted in future studies.     

Analysis of changes of insect-plant ratio-improvement of key-factor analysis for evaluating bottom-up effects in insect population dynamics

A revised key-factor analysis was presented for analyzing the temporal changes in the ratio of insect absolute number to plant resource. Ten data sets for 5 insect species were then analyzed. In this key-factor analysis, the key factor is defined as the factor contributing highly to between-year variation inR _r , the log rate of the inter-year change of the insect-plant ratio. The yearly change of plant resource was handled as a separate factor, expressed byr _pl , log ratio of plant resource in yearn to plant resource in yearn+1. The following was revealed: 1) In 7 of the 10 data sets examined,r _pl influenced variations ofR _r ; in particular in 3 casesr _pl was the main key factor. 2) Generation-to-generation fluctuations of absolute insect densities showed density dependence in 4 cases, while those of insect-plant ratios, in 8 cases. 3) The Royama model or a linear model, explained well the relationship between log insect-plant ratio (X _r ) andR _r and the relationship betweenX _r and log yearly change rate of absolute insect density (R _abs ). However, in the 7 cases in whichr _pl was a critical factor for variations ofR _r , with, increase ofX _r ,R _r showed a steeper, decrease around the equilibrium point (the point for whichR _r is 0) thanR _abs . This occurred becauser _pl tended to be negatively correlated withX _r . Consequently, in two casesX _r fluctuated cyclicly or chaotically although without the changes in plant resource, fluctuations ofX _r would be damped oscillations approaching equilibrium.     

On the mathematical basis of the variance-mean power relationship

The mathematical basis of a widely-known variance-mean power relationship of ecological populations was examined. It is shown that the log variance (S ²)—log mean, (m) plot is virtually delimited by two lines logS ²=logn+2 logm and logS ²=logm, thus increasing the chance that a linear regression line can be successfully fitted, without a profoundly behavioural background. This makes difficult the task of interpreting a successful fit of the power law regression and its parameterb in a biologically meaningful manner. In comparison with the power law regression, Iwao'sm ^*-m regression is structurally less constrained, i.e. has a wider spatial region in which data points can scatter. This suggests that a comparison between the two methods in terms of how good a fit is achieved for a particular data set is largely meaningless, since the power law regression may inherently produce a better fit due to its constrained spatial entity. Furthermore, it could be argued that a successful fit in Iwao's method, when found, is less taxed with mathematical arterfacts and perhaps more clearly linked to some biological mechanisms underlying spatial dispersion of populations.     

Effects of host and parasitoid age on search behaviour and oviposition rates inLariophagus distinguendusF?rster (Hymenoptera: Pteromalidae)

Summary Oviposition rates and related behaviours were quantified forLariophagus distinguendus F?rster attackingCalosobruchus chinensis (L.) andC. maculatus (F.). Oviposition rates varied with parasitoid age; parasitoids aged 1–7 days laid approximately twice as many eggs per day as those aged 8–14 days. Similar differences were noted in search rates and handling times; younger parasitoids had higher attack rates and lower handling times than older parasitoids. Search rates and handling times also varied with the host stage available for attack. Search rates were higher and handling times were lower on larger stages. The results are discussed with reference to their impact on the dynamical behavior of insect parasitoid-host populations.     

Life Satisfaction of Older Adults in Hong Kong: The Role of Social Support from Grandchildren

This study explores the relationship between the life satisfaction of older adults and the social support from grandchildren in Hong Kong. Two hundred and fifteen older people (from the ages of 64 to 101, mean age 79.3), whose youngest grandchild was aged 12 or older, were recruited from elderly service agencies to participate in the study. Face-to-face interviews were conducted by trained interviewers using a standardized questionnaire, which included the Life Satisfaction Scale for Chinese, the Lubben Social Network Scale, the Chinese Tradition Scale, grandchildren social support measures, self-rated health, self-rated financial adequacy, and demographic variables. Hierarchical regression showed that the life satisfaction of older adults benefitted significantly from the social support from grandchildren (R ² change = .05, F _change = 7.15, p < .001); while controlling demographic characteristics, general social support, attitude towards Chinese tradition, self-rated health, and self-rated financial adequacy. The total explained variance was 51%. Emotional support and appraisal support from grandchildren were identified as significant contributing factors. The policy and practice implications for active aging policies are discussed in a Chinese context.     

Bayesian Estimation for Quantification by Real-time Polymerase Chain Reaction Under a Branching Process Model of the DNA Molecules Amplification Process

The aim of Quantitative Polymerase Chain Reaction is to determine the initial amount X ₀ of specific nucleic acids from an observed trajectory of the amplification process, the amplification being achieved through successive replication cycles. This process depends on the efficiency {p _n } _n of replication of the DNA molecules, p _n being the probability that a molecule will duplicate at replication cycle n. Assuming p _n  = p for all n, Bayesian estimators of the unknown parameter θ = (p, X ₀) are constructed by Markov Chain Monte Carlo methods under a Bienaymé-Galton-Watson branching model of the amplification process. The Bayesian approach takes into account some prior information on the parameter. Relying on simulated data, the proposed Bayesian estimators and their credibility sets are shown to be quite accurate.     

Validation of the WeDQoL-Goals-Thailand Measure: Culture-Specific Individualised Quality of Life

The aim of this study was to validate an individualised measure of quality of life (WeDQoL-Goals-Thailand). Three hundred and sixty-nine Thai people completed the WeDQoL by interview. Respondents rated (0–2) the perceived necessity for wellbeing of 51 goals (goal necessity), then rated (0–3) their satisfaction with the same goals (goal satisfaction). Weighted goal attainment (possible range 0–6) was computed (necessity x satisfaction). Psychometric validation used frequency distributions, Principal Components Analysis (PCA), and Cronbach’s alpha. Analysis of variance, t-tests, Kruskal–Wallis, Mann–Whitney U, Spearman’s correlation and multiple regression explored socio-demographic, geographic and economic differences. Respondents were aged 15–89 (mean 45.7, SD 18.0); 169 men, 200 women. For weighted goal attainment scores, PCA found a 44-item scale (α = 0.91) and three subscales (community/social/health, α = 0.90; house and home, α = 0.80; nuclear family, α = 0.81). Thai Individualised Goal Attainment (TIGA) scale and the three subscales were computed as the mean of contributing weighted goal attainment scores, after excluding goals considered ‘not necessary’ to each individual. Unweighted and individualised scores differed significantly with socio-demographic, geographic and economic indicators. In multiple regression, both Thai Unweighted Goal Satisfaction (TUGS) and TIGA scale scores were predicted by being married, living in the South and in a non-urban location. TIGA scores were also predicted by being over 25 years old. WeDQoL-Goals-Thailand has excellent psychometric properties. Individualised scores reflect each person’s perspective on wellbeing and are sensitive to subgroup differences. However, unweighted satisfaction scores give a broadly similar picture and involve less complex computation.     

Binomial sampling plans for estimatingBemisia tabaci populations in cantaloupes

Early season infestations of the sweet potato whitefly,Bemisia tabaci (Gennadius), on cantaloupes,Cucumis melo L., were determined by counts of the number of adults per leaf in fields near Yuma, Arizona. We used these data to develop binomial sampling plans based on the relationship between mean densities of whiteflies per leaf,m, and proportion of leaves infested with more thanI whiteflies,P _I, according to the empirical model lnm=a′+b′ ln[−ln(1−P _I)]. The models were developed for the presence-absence approach (I=0) and for a cutoff value of three whiteflies per leaf (I=3). Four independent data sets were used to evaluate the models. Both methods yielded reliable predictions at low infestation levels, but some of the higherm values were overestimated. As the tentative economic threshold forB. tabaci is three adults per leaf, which corresponds to lowP _I values, results of the binomial sampling were satisfactory for pest management purposes.     

A Translation and Validation Study of the Life Orientation Test Revised in the Greek Speaking Population of Nurses among Three Hospitals in Athens and Ioannina

The life orientation test-revised (LOT-R) (Scheier et al. in Journal of Personality and Social Psychology 67:1063–1078, 1994) is a brief measure for assessing dispositional optimism. The aim of this study was to develop a Greek language version of the LOT-R and to assess the instrument’s psychometric properties. The LOT-R was translated and culturally adopted in Greek language, and the final version was administered, along with a questionnaire consisting socioeconomic characteristics and a single item measuring optimism, to 276 Greek speaking, hospital nurses (222 female, 54 male), aged 22–65 years (mean 37.8, SD 8.3). Results showed that the LOT-R has good internal consistency (Cronbach’s α = .71 and item total correlation coefficients from .27 to .73, a unitary structure, and stability over a 3-months period (r = .66). Moreover, the Greek version of the scale exhibited good convergent validity with single-item optimism scale (r = .73). Principal components analysis revealed a two-factor structure representing the constructs of optimism and pessimism. The Greek life orientation test revised appears to be a valid tool in assessing dispositional optimism in Greek speaking people and is expected to facilitate the examination of optimism in Greek speaking populations.     

Host-size-dependent sex ratio in a parasitoid wasp

Charnov's host-size model explains parasitoid host-size-dependent sex ratio as an adaptive consequence when there is a differential effect of host size on the offspring fitness of parasitoid males versus females. This article tests the predictions and the assumptions of the host-size model. The parasitoid wasp Pimpla nipponica Uchida (Hymenoptera: Ichneumonidae) laid more female eggs in larger or fresher host pupae when choice among hosts of different sizes or ages was allowed. Then, whether an asymmetrical effect of host size and age on the fitness of females versus males existed in P. nipponica was examined. Larger or fresher host pupae yielded larger wasps. Larger females lived longer, whereas male size did not influence male longevity. Large males mated successfully with relatively large females but failed with small females, whereas small males could mate successfully either with small or with large females. Thus, small-male advantages were found, and this held true even under male–male competition. Ovariole and egg numbers at any one time did not differ among females of different sizes. Larger females attained higher oviposition success and spent less time and energy for oviposition in hosts. Larger females produced more eggs from a single host meal. Taken together, females gained more, and males lost more, by being large. Host size and age thus asymmetrically affected the fitness of offspring males versus females through the relationships between host size or hast age and wasp size, which means the basic assumption of the host-size model was satisfied. Therefore, sex ratio control by P. nipponica in response to host size and age is adaptive. Received: November 13, 1998 / Accepted: January 18, 1999     

A pilot study combining Go4Life® materials with an interactive voice response system to promote physical activity in older women

ABSTRACT

Telephone-based interactive voice response (IVR) systems could be an effective tool for promotion of physical activity among older women. To test IVR feasibility, we enrolled 30 older women in a 10-week physical activity intervention designed around National Institute on Aging (NIA) Go4Life® educational materials with IVR coaching. Participants (mean age = 76 years) significantly increased physical activity by a mean 79 ± 116 (SD) minutes/week (p < .001). Participants reported that the Go4Life® materials, pedometer, and IVR coaching (70% reported easy technology) were useful tools for change. This pilot study demonstrates IVR acceptability as an evidence-based physical activity program for older women.