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     

Spatio-temporal variation of natural and sexual selection in breeding populations of the coreid bug,Colpula lativentris (Heteroptera: Coreidae)

Spatio-temporal variations of lifetime reproductive succes (LRS) of both male and female individuals of a coreid bugColpula lativentris were measured and analyzed using the multiple regression method of Arnold and Wade (1984a, b). The standardized variance of LRS was larger in males than that in females as males often to secure mates for a long period whereas females could easily find mates and oviposit simply dependent on ovarial maturation. LRS was partitioned into 4 consecutive fitness components: (1) reproductive lifespan, (2) copulating efficiency, (3) guarding efficiency (for males) or oviposition efficiency (for females), and (4) number of eggs per clutch. In males copulating efficiency was the largest determining factor of LRS, whereas in females reproductive lifespan was the most important factor. Such tendencies were stable on both a yearly and local basis. Patterns of relative contribution of natural selection (reproductive lifespan and number of eggs per clutch) and sexual selection (copulating efficiency and guarding or oviposition efficiency) to LRS were clearly different between males and females. This sexual difference is, at least to some extent, thought to be brought about by sexual selection among males for mating opportunity, though no physical fight was observed among males. Directional selection on body length was found only in relation to the clutch size of females because large females tended to lay larger clutches. No significant directional selection was found in other fitness components.     

Selection and reproductive success in males of the dragonfly,Orthetrum japonicum (Odonata: Libellulidae)

Reproductive success, copulation success, and mating success were measured for a population of male dragonflies,Orthetrum japonicum. Copulation success explained the greatest variation in reproductive success. The proportion of copulations followed by oviposition was positively correlated with the number of oviposited eggs per mating. Directional selection on four morphological characters was estimated. The effect of selection on correlated traits was comparable to that of direct selection. Directional selection varied between traits and between episodes in a single trait. The probability that the observed directional selection on the four morphological traits was expected under the condition of the selective neutrality of traits was not smaller than 5%.     

A measure of sexual selection for interspecific comparisons of species with diversified mating systems and different mortality schedules

Summary Based on variances in components of lifetime reproductive success (LRS), a new index of the intensity of sexual selection was proposed mainly useful for interspecific comparisons. The index was defined as the male to female ratio of the standardized variance in mating efficiency during mating period. The index can to a large extent exclude the effect from natural selection which commonly act on both sexes in mating period and also from mortality in pre-reproductive period. This empirical measure has some defects in the strict sense (i.e., dichotomy of natural and sexual selection), however, it enables interspecific comparisons of the intensity of sexual selection among different taxonomic groups of animals with various mating systems and mortality schedules.     

Environmentally Responsible Happy Nation Index: Towards an Internationally Acceptable National Success Indicator

Amidst increasing attention to happiness studies by economists, the New Economics Foundation launched in July 2006 the Happy Planet Index (Marks et al. 2006). This is the ratio of the average happy life years (HLY) to the per capita ecological footprint of the country concerned. HLY is in turn the product of the average happiness (or life satisfaction) index and the life expectancy index. Some essential revisions to this index are proposed to reach an internationally acceptable national success indicator that aims positively at long and happy lives but negatively at the external costs of environmental disruption. Hopefully, this ‘environmentally responsible happy nation index’ will lead to some re-orientation of both the market and national governments towards something more fundamentally valuable.

A comparison of species diversity estimators

Although having been much criticized, diversity indices are still widely used in animal and plant ecology to evaluate, survey, and conserve ecosystems. It is possible to quantify biodiversity by using estimators for which statistical characteristics and performance are, as yet, poorly defined. In the present study, four of the most frequently used diversity indices were compared: the Shannon index, the Simpson index, the Camargo eveness index, and the Pielou regularity index. Comparisons were performed by simulating the Zipf–Mandelbrot parametric model and estimating three statistics of these indices, i.e., the relative bias, the coefficient of variation, and the relative root-mean-squared error. Analysis of variance was used to determine which of the factors contributed most to the observed variation in the four diversity estimators: abundance distribution model or sample size. The results have revealed that the Camargo eveness index tends to demonstrate a high bias and a large relative root-mean-squared error whereas the Simpson index is least biased and the Shannon index shows a smaller relative root-mean-squared error, regardless of the abundance distribution model used and even when sample size is small. Shannon and Pielou estimators are sensitive to changes in species abundance pattern and present a nonnegligible bias for small sample sizes (<1000 individuals). Received: May 8, 1998 / Accepted: May 6, 1999     

Differences in adult and reproductive lifespan in the two male forms ofMnais pruinosa costalis selys (Odonata: Calopterygidae)

The damselflyMnais pruinosa costalis (Odonata: Calopterygidae) is unusual in that males are dimorphic, existing as clear-winged non-territorial ‘sneaks’ and orange-winged territorial ‘fighters’. Here we report the results of population census data and behavioural observations in the field and laboratory, and present estimates of emergence period, reproductive period, total lifespan, and reproductive success of each morph. Clear-winged males are smaller and have lower daily reproductive success than orange-winged males, but live for longer in the field and laboratory. We accounted for the difference in the ‘operational reproductive life’ of the two morphs and estimated lifetime reproductive success: there was no difference between clear-winged and orange-winged males. We discuss possible mechanisms for the maintenance of the two forms.     

Union organizing effort and success in the U.S., 1948–2004

While union density in the public sector has increased in recent decades, private sector union density in the U.S. has declined steadily since the mid-1950s. Scholars have evoked a variety of explanations to account for the decline in union membership, but substantially less attention has been devoted to understanding the contribution of the union organizing process as governed by the National Labor Relations Board (NLRB). In this paper, we focus on two aspects of this process: union organizing effort (the effort to establish union representation elections to organize non-unionized workers) and union organizing success (success in winning union representation elections). Using annual time series data for the U.S. from 1948 to 2004, we show that there has been a long-term decline in both union organizing effort and union organizing success, which likely contributes to declining union density. We focus on three explanations for these changes: the political–legal environment for unions, deindustrialization and globalization, and employer opposition to unionization efforts. We find that each of these factors contributes to organizing effort and success and conclude with a discussion of the implications of this research for future mobilization efforts.     

Lifetime mating success of males in a natural population of the papilionid butterfly,Atrophaneura alcinous (Lepidoptera: Papilionidae)

Summary Lifetime mating success of males in a natural population of the papilionid butterfly,Atrophaneura alcinous, was investigated and causes of the variation were examined. The most successful males mated with 5 females, whereas about 73% of the males failed to mate. Body size of males was not correlated with their eclosion date, longevity and lifetime mating success. There was no trade-off between mating success and longevity, and long-lived males had a disproportionately high mating success. Although number of available females per male per day was not variable among males with different longevities, long-lived males had higher mating efficiency. Time interval between matings by non-virgin males was shorter than that from eclosion to the first mating. High lifetime mating success of long-lived males was strongly related to their mating experience, not to their ageper se.     

Estimating the impact of change in pre-pregnancy body mass index on development of Gestational Diabetes Mellitus: An Australian population-based cohort

BackgroundInternational studies examining maternal overweight and obesity have found GDM risk increases with increasing weight gain between pregnancies.AimThe study aimed to estimate the association between pre-pregnancy maternal body mass index (BMI), change in BMI between pregnancies and Gestational Diabetes Mellitus (GDM) amongst women with consecutive births in an Australian cohort.MethodsWe used a population cohort of women who had at least two consecutive singleton births between 2010 and 2017 in one NSW health district to investigate the risk of GDM in the pregnancy after the index pregnancy, BMI change between pregnancies and the impact of BMI change on risk of GDM.FindingsOf 10,074 women 1987 (16.7%) had no GDM in the index pregnancy but GDM in the subsequent one while 823 (8.2%) had GDM in both pregnancies. No change in BMI between pregnancies occurred in 47% of women, while 12% had a decrease and 41% an increase. After adjusting for socio-demographic characteristics and selected maternal and perinatal confounders, a reduction in BMI between births in women without GDM in the index pregnancy was associated with a 36% lower risk in GDM (aRR: 0.64; 95% CI: 0.49?0.85), while an increase in BMI was associated with increased risk of GDM with the greatest risk amongst those who gained 4+ kg/m² (aRR 2.27; 95%CI: 1.88–2.75).ConclusionInterpregnancy weight change is an important modifiable risk factor for the risk of GDM in a subsequent pregnancy. Clinical guidelines and health messages about interpregnancy weight change are important for all women.     

人口现代化的测度指标体系构建问题研究

研究人口现代化,必须很好解决的一个问题就是要确定并建立一套可供参照的人口现代化指标体系。通过对人口现代化理论的基本把握,在确定数据样本及基本构建方法的基础上,以人口再生产类型现代化、人口素质现代化、人口结构现代化和逆人口现代化作为基本测度内容,以最能反映基本测度内容的指标群来构成考量人口现代化水平的通用指标体系。构建具有国际可比性或区域可比性、相对完善而更具指标体系特征和应用价值的人口现代化测度指标,为制定相应的人口发展战略、政策、规划等提供科学依据。     

基于省级面板数据的劳动者工资扭曲测度

本文利用1999—2012年省级面板数据,基于C-D生产函数对我国各省历年劳动者工资扭曲指数进行测度。研究结果发现：（1）我国各省劳动者工资普遍存在向下扭曲;（2）劳动者工资扭曲指数的时间趋势表现为先升后降,近4年趋于稳定的态势;（4）劳动者工资扭曲的省际差异的变动轨迹为：先逐渐缩小,再大幅度频繁波动,后平缓缩小;（4）劳动者工资扭曲存在地区差异,扭曲程度从高到低依次为东部地区、中部地区和西部地区。（5）劳动者工资扭曲指数并不完全取决于当地实际工资水平。由此,本文建议是：制定抑制地区间恶性引资竞争的宏观政策,建立以贸易利益最大化为目标的贸易发展模式,完善劳动力市场制度化建设,加强法律和工会对劳动者权益的保护,完善社会保障制度,扩大财政支出,从而减轻劳动者工资扭曲程度。     

Active female courtship behavior and male nutritional contribution to female fecundity in Bruchidius dorsalis (Fahraeus) (Coleoptera: Bruchidae)

Mating behavior and the male's contribution to female fecundity were studied in the bean weevil Bruchidius dorsalis (Fahraeus) (Coleoptera: Bruchidae) in comparison with two other species, Callosobruchus chinensis (which infests stored beans) and Kytorhinus sharpianus (which feeds on wild legumes). Only females of B. dorsalis showed multiple mating and characteristic precopulatory behavior that appeared to solicit the male's nutritious secretion. In contrast, all females of the other two species did not copulate multiply and did not show such precopulatory behavior. In B. dorsalis, the decrement of male body weight just after copulation indicated that seminal fluid weighing as much as approximately 7% of the male's body weight was transferred to the female. Fecundity was more than eight times higher in females that had copulated ten times than in females that had copulated only once, indicating that males paid most of the nutritional cost of egg production. These facts suggest that the sex role is reversed in B. dorsalis. Received: May 22, 1998 / Accepted: July 19, 1999     

The nutrition-related information seeking behaviours and attitudes of pregnant women with a high BMI: A qualitative study

BackgroundThe prevalence of high body mass index is increasing amongst women of child bearing age. High maternal body mass index has ramifications for both mother and baby including increased health risks from gestational diabetes mellitus, caesarean section and stillbirth. Despite the increasing prevalence of high maternal body mass index little is known of the experiences of these women regarding nutrition information access and use during the antenatal period.MethodsA qualitative study using individual interviews was undertaken at a tertiary hospital in south-eastern Australia. Twenty-Eight women with a body mass index ≥30 kg/m² participated. Interviews were audio recorded, transcribed, cross-checked for consistency and entered into a word processing document for further scrutiny. Data was analysed using interpretative phenomenological analysis (IPA). In any phenomenological study the researcher’s objective is to elicit the participant’s views on their lived experiences.FindingsThree major themes emerged: (1) Nutrition-related information attainment; (2) Nutrition-related information management; (3) Nutrition-related information needs and wants.ConclusionThe findings from this study may assist the future development and dissemination of nutrition-related information for pregnant women with a high body mass index. Women want more individualised support regarding nutritional requirements during pregnancy.     

Welfare State Development in Latin America and the Caribbean (1970s–2000s): Multidimensional Welfare Index,Its Methodology and Results

There is an ongoing debate between focalization and universalization on welfare policies as the best way to develop the welfare state in Latin America and the Caribbean. However, there is a need to develop a measure that exhibits the multidimensional nature of the welfare state, instead of focusing on the social spending dimension. Segura-Ubiergo (The political economy of the welfare state in Latin America: globalization, democracy and development. Cambridge University Press, New York, 2007) constructed a welfare effort index (WEI) to facilitate understand the relative degrees of welfare state development among Latin American countries. The WEI focuses mainly on social spending and ignores the other dimensions of welfare. Based on a comparative analysis of 17 Latin American countries and following the methodology of Segura-Ubiergo, a new index that aims at enriching the WEI was constructed. The new index is multidimensional in that it has eight indicators relating to three dimensions of welfare: social spending, coverage of welfare programs and outcome of welfare institutions. Principal component analysis was used for reducing the indicators into three indexes that represent three proposed dimensions of welfare. The combination of these three indexes gives the multidimensional welfare index. The results of the index account for more than 75 % of the data variance.     

Can consumers detect lemons? An empirical analysis of information asymmetry in the market for child care

This paper tests adverse selection in the market for child care. A unique data set containing quality measures of various characteristics of child care provided by 746 rooms in 400 centers, as well as the evaluation of the same attributes by 3,490 affiliated consumers (parents) in the U.S., is employed. Comparisons of consumer evaluations of quality to actual quality show that after adjusting for scale effects, parents are weakly rational. The hypothesis of strong rationality is rejected, indicating that parents do not utilize all available information in forming their assessment of quality. The results demonstrate the existence of information asymmetry and adverse selection in the market, which provide an explanation for low average quality in the U.S. child care market.

The City of Saskatoon’s Local Area Planning Program: A Case Study

The City of Saskatoon’s Local Area Planning (LAP) Program is a community-based approach to developing comprehensive neighbourhood plans. In order to achieve sustainable and implementable Local Area Plans (LAPs), the City of Saskatoon has been using innovative methods of collaborative decision-making to engage citizens. The program has been recognized nationally by the Federation of Canadian Municipalities for demonstrating innovative approaches to citizen engagement in Sustainable Community Planning. A total of eight LAPs have been adopted by City Council and 212 recommendations have been approved, with 101 of these recommendations being completed, 71 currently in progress and 40 to be determined. Great strides have been made to implement the LAPs by allocating resources for coordinating implementation, working with communities, and for implementing the various recommendations. In addition, over 1,000 people representing various interests have participated in one or more LAP Committee or implementation meetings. Through this participation, partnerships have been formed, program and service delivery has been improved, and most importantly, communities have taken ownership of their plans. After completing eight LAPs, the LAP communities, City Council and city planners have felt the need to measure ongoing changes and progress in the LAP communities. In recognition of this, the City of Saskatoon’s City Planning Branch will be working with LAP communities, the Community-University Institute for Social Research (CUISR) and other stakeholders to develop a framework for statistically measuring changes in LAP communities and to monitor “Neighbourhood Success Factors”. The Neighbourhood Success Factors will work to detect serious socio-economic conditions before they reach a point of crisis. This paper will first describe the LAP Program before reviewing the proposed framework for statistically measuring changes in Saskatoon’s neighbourhoods.

The impact of Multiple Mini Interviews on the attrition and academic outcomes of midwifery students

BackgroundAdmission to the Bachelor of Midwifery (BMid) in Australia has traditionally been based on academic ranking. The BMid is a high demand course offered to a limited number of students and therefore choosing applicants who complete the degree is important. Multiple Mini Interviews (MMIs) are used to assess non-cognitive skills and select students into healthcare degrees. One university in Australia has introduced MMIs as part of the application process for the BMid.AimCompare attrition rates and Grade Point Average (GPA) scores between students admitted into the BMid using both academic ranking and MMIs, to those admitted on academic ranking alone.MethodsA basic convergent mixed methods design, using an explanatory unidirectional framework to integrate data. Attrition rates, GPA, and multiple mini interview scores (2013–2019), were linked and compared for before and after the use of MMI’s. Focus groups with students, interviewers, and hospital-based educators, explored stakeholder experiences. Open-ended questions from an applicant survey were added to the qualitative data set, which was analysed thematically.FindingsStudents who enrolled via the MMI’s had significantly lower attrition rates than those enrolled before MMI’s were introduced. GPA scores were significantly higher for students who enrolled via the MMI’s. Integration of data found MMI’s identified students passionate to undertake midwifery, and that success at the interviews increased students’ confidence to successfully complete their studies.ConclusionMMI’s as part of the entry process into the BMid enabled identification of applicants more likely to remain in the course and succeed in their studies.     

Income Inequality Indices Interpreted as Measures of Relative Deprivation/Satisfaction

This paper considers different ways of making comparisons between individuals in terms of deprivation and/or satisfaction. This allows the Gini index, the Bonferroni index and the De Vergottini index to be interpreted as social deprivation measures as well as social satisfaction measures. The inequality measures that belong to the ?? family, or linear combinations of them, are obtained when using different weighting schemes to average the deprivation and satisfaction associated with each income level. Particularly, the generalised Gini indices (Yitzhaki, Int Econ Rev 24:617?C628 in 1983), the indices proposed by Aaberge (J Econ Inequal 5(3):305?C322, 2007) or those proposed by Imedio-Olmedo et al. (J Public Econ Theory 13(1):97?C124, 2011) can be used to evaluate social deprivation or social satisfaction in an income distribution.