Why does onlyAthalia Japonica enter summer diapause among three sympatricAthalia sawflies feeding on crucifers?

Summary This report assesses the primary factor for the evolution of summer diapause of the three species of sawfly,Athalia japonica, A. rosae andA. infumata that feed on cruciferous plants and coexist in the same area.A. japonica has two discrete spring and autumn generations, butA. rosae andA. infumata 5–6 generations. OnlyA. japonica enters summer diapause in response to the long daylengths in spring. Although these three sawflies usually feed on the same cultivated crucifers, they differ markedly in the utilization of wild crucifers. They oviposit only on young leaves.A. japonica mainly usesCardamine plants which sprout in spring and autumn.A. rosae andA. infumata primarily use hosts with new leaves all the year round, i.e. cultivated crucifers andRorippa indica, respectively. The thermal threshold for development is lower inA. japonica than in the other two species. The low heat tolerance ofA. japonica is adapted only to cool shady habitats whereCardamine grows. Presumably, summer diapause ofA. japonica is adaptation to the deterioration of the primary host plants rather than unfavorable climatic conditions. This interpretation is supported by the movement patterns of the threeAthalia sawflies, alternative means to escape from deteriorated habitat conditions.     

Combining Happines’s and Suffering in a Retrospective View of Anchor Periods in Life: A Differential Approach to Subjective Well-Being

The intersection of dimensions of subjective well-being (SWB) generates SWB types. We delineated SWB types by cross-tabulating happiness and suffering ratings that participants attributed to outstandingly meaningful periods in their life referred to as anchor periods. A sample of 499 older Israelis (age 58–94) was queried about two positive periods (the happiest, the most important) and two negative periods (the most miserable, the most difficult). A variety of variables discriminated between the more frequent congruous types of Happy (high happiness and low suffering) and Unhappy (low happiness and high suffering), but also presented the incongruous types of Inflated (high happiness and high suffering) and Deflated (low happiness and low suffering) as discriminable. Thus, women were more likely to be Inflated whereas men were more likely to be Deflated; low education related more to Happy in the happiest period and to Unhappy in the negative periods; present life satisfaction related more to Happy than to Unhappy in the positive, but not in the negative, periods; and Holocaust survivors were more likely to be Deflated and Unhappy in the negative, but not in the positive, periods. The study supported a differential perspective on SWB within people’s narratives of their lives. An erratum to this article is available at .     

Spatio-temporal distribution patterns of two tachinid flies,Epicampocera succincta andCompsilura concinnata parasitizingPieris

Summary Larvae of genusPieris in the northern part of Kyoto City are parasitized by two tachinid flies:Epicampocera succincta, a specialist on genusPieris, andCompsilura concinnata, a generalist with very wide host-range. We surveyed the parasitism rates ofPieris by both flies for two years at six study areas. In these study areas, there lived three host species in the genusPieris: P. rapae, P. melete, andP. napi, but neither tachinid parasitizedP. napi to any significant extent. In the mountainous district,P. rapae andP. melete coexisted and their populations were relatively continuous, while in the lowland, onlyP. rapae larvae were abundant in spring and autumn, but even they disappeared in summer. Parasitisms byE. succincta occurred mainly in mountainous district and never in the lowland.C. concinnata parasitizedPieris in all the areas, but its parasitisms occurred mainly in autumn. We analyzed the factors affecting the spatial and temporal patterns of parasitism rates and presumed that the temporal discontinuity of host population restricted the distribution of the specialist parasitoid.     

Counter-Examples about Lower- and Upper-Bounded Population Growth

ABSTRACT

For a unimodal growth function f having its maximum at a critical state x _c , the interval bounding the population size asymptotically is usually presented as being equal to [f ^○2(x _c ), f(x _c )]. This interval however does not represent the maximum range within which the population size can vary, even asymptotically. The actual invariant interval containing the population size is equal to: [min(x*, f ^○2(x _c )), f(x _c )], where x* denotes the non-zero fixed point, assumed to be unique, of the iteration of f.     

An Interrupted Postcolonial/Feminist Cyberethnography: Complicity and Resistance in the "Cyberfield"

Informed by Foucault's theorisation of the docile body, the gaze, and the Panopticon, we analyse how the gaze is operationalised in the popular makeover show How to Look Good Naked (HTLGN). We explore how a regime of discipline is (re)produced through the drawing of boundaries constructing the feminine/masculine and straight/queer binaries. We analyse the delineation of rules and the performance of practices to maintain these boundaries, which support emphasised femininity and hegemonic masculinity. Whilst HTLGN claims to challenge the “body fascism” prevalent in the fashion, beauty, and advertising industries and rid women, and more recently men, of the shame associated with not meeting these ideals, we argue that the show's resistance is far from radical, functioning instead as a mediated ritual of rebellion, endorsing and sustaining key elements constituting prevailing constructions of femininity and masculinity.     

Crucial factors determining the spatio-temporal distribution patterns of threeAthalia sawflies feeding on common cruciferous plants

Summary ThreeAthalia sawflies,A. japonica, A. rosae andA. infumata, feeding on cruciferous plants, coexist in Japan. However, it is not known what ecological strategies they use and what environmental factors are crucial to such strategies. I attempted to explain these questions by examining the relationship between the spatio-temporal distribution patterns of threeAthalia sawflies and their habitats in three districts (Lowland, Intermediate and Mountain). The three sawflies have different spatio-temporal distribution patterns, though they usually used common cruciferous plants.A. japonica was abundant in spring and autumn but disappeared during summer in all the districts. In the Lowland, populations ofA. rosae andA. infumata, like that ofA. japonica, crashed in summer. HoweverA. rosae occurred mainly in summer in the Intermediate and Mountain. AlthoughA. infumata occurred in the same seasons asA. rosae in all districts, population levels ofA. infumata were always lower than those ofA. rosae. The crucial factors controlling their population patterns were the availability of host plants and temperature. Population crashes ofA. rosae andA. infumata were due to food depletion, and those ofA. japonica were due to heat stress. On the other hand, their population patterns may be interpreted as phenological synchronization with their original host plants, though they all existed on common cruciferous plants. The three sawflies may have evolved different strategies to escape from unfavorable habitat conditions. Such strategies are speculated to be summer diapause inA. japonica, long distance migration inA. rosae, and local dispersal inA. infumata.     

Competition between laboratory populations of green leafhoppers,Nephotettix spp. (Homoptera: Cicadellidae)

Summary Intra- and interspecific competition between laboratory populations of four green leafhoppers,Nephotettix spp. was studied in the laboratory under three different temperature regimes of 24°C, 27°C and 30°C. For the single-species population of the three tropical species, the equilibrium density increased as the temperature increased. On the other hand, for the temperature speciesN. cincticeps, the highest equilibrium density was at the intermediate temperature and the lowest at high temperature. Interspecific interactions between two tropical (N. virescens vs.N. nigropictus), a tropical and a temperature (N. virescens vs.N. cincticeps) and a rice-feeding and a grass-inhabiting (N. virescens vs.N. malayanus) Nephotettix species were also studied in the laboratory at the three temperature regimes. Temperature differentially affected the outcome of competition between twoNephotettix species. BetweenN. virescens andN. nigropictus, the latter was more successful over the former at low and intermediate temperatures, while the former was more successful at high temperature. BetweenN. virescens andN. cincticeps, the temperate species inhibited the growth of the tropical species at low temperature while the tropical species inhibited the growth of the temperate species at high temperature. At intermediate temperature, the population ofN. virescens persisted at a slightly higher density over the population ofN. cincticeps. Between the rice-feedingN. virescens and the grass-inhabitingN. malayanus, regardless of temperature the population density of the latter was greatly reduced and later became extinct while the population of the former continued its growth. These consequences of competition between twoNephotettix species conformed fairly well to those predicted by theLotka-Volterra model using demographic parameters specified for each species.     

A magical model of happiness

A model of happiness is described that is based on nonlinear mathematics. Happiness at timet+1 is given by:Hnext=M(1–H)H+I, whereH is happiness at timet, M is a person parameter, andI is an environmental impact term comprised of a prevailing component (Ip) and an episodic component (dI). Eight properties of the model are detailed and its utility illustrated for reconciling problematic issues in the literature that include the positive skew in the distribution of psychological well being (PWB) scores, the stability and change in PWB, and the relationships of emotionality with global PWB and its indicators. The operationalization of the model is described from the population level down to that of the single case.     

A comparative study of the searching efficiencies of a parasite and a hyperparasite

Summary The searching efficiencies of a primary parasite (Diaeretiella rapae (McIntosh)) and a hyperparasite (Alloxysta brassicae (Ash.)) were investigated and compared. In both species, at all parasite densities, there was a curvilinear relationship (P<0.001) between the number of hosts parasitised and the host density. A linear regression (loga=logQ−m logP) was fitted for log area of discovery against log parasite density (P<0.001). The area of discovery for its immediate (i.e. primary) host (viz.Diaeretiella for the hyperparasite and aphid forDiaeretiella) is lower in the hyperparasite than in the primary parasite. InDiaeretialla both the searching efficiency and the mutual interference constant increased (but not significantly,P>0.05) in the presence of its males.     

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.     

Comparative studies on the seasonal occurrence, nymphal development and food menu in two giant water bugs,Diplonychus japonicus vuillefroy andDiplonychus major esaki (Hemiptera: Belostomatidae)

Summary We compared the seasonal changes in population density and nymphal development at different water temperatures and under different food conditions between two giant water bugs,Diplonychus japonicus andD. major, in Okayama, Japan. D. japonicus produced 1–2 generations a year, whileD. major was strictly inivoltine. The developmental velocity was higher inD. japonicus than inD. major. The thermal constant ofD. japonicus was less than that ofD. major. These results suggest thatD. japonicus is adapted, to higher water temperature thanD. major. In the field,D. japonicus preyed predominately on Lymnaeidae and Physidae snails, whileD. major preyed on aquatic insects such as dragonfly nymphs.     

Simplifying the Water Poverty Index

In this paper, principal components methodology is used to derive simplified and cost effective indexes of water poverty. Using a well known data set for 147 countries from which an earlier five-component water poverty index comprising of Resources, Access, Capacity, Use and Environment was constructed, we find that a simplified three-component composite index comprising of Access, Capacity, and Environment, with unequal weights, or its two-component counterpart comprising of Capacity and Environment with equal weights, would be more cost-effective to construct without much loss of information. These simplified indexes have high positive and negative correlations with the Human Development Index and the Human Poverty Index, respectively.     

BOOK REVIEWS

John M. BarryThe Great Influenza: The Epic Story of the Deadliest Plague in History Jacqueline Scott, Judith Treas, and Martin Richards (eds.) The Blackwell Companion to the Sociology of Families Brígida García, Richard Anker, and Antonella Pinnelli (eds.) Women in the Labour Market in Changing Economies: Demographic Issues Samuel P. HuntingtonWho Are We? The Challenges to America's National Identity Herbert S. KleinA Population History of the United States Jean Elisabeth PedersenLegislating the French Family: Feminism, Theater, and Republican Politics, 1870–1920 Peter SingerOne World: The Ethics of Globalization Jagdish BhagwatiIn Defense of Globalization Vanessa L. FongOnly Hope: Coming of Age Under China's One‐Child Policy Arianne M. Gaetano and Tamara Jacka (eds.) On the Move: Women in Rural‐to‐Urban Migration in Contemporary China Peter S. HellerWho Will Pay? Coping with Aging Societies, Climate Change, and Other Long‐Term Fiscal Challenges Phillip LongmanThe Empty Cradle: How Falling Birthrates Threaten World Prosperity and What to Do About It William PetersenFrom Persons to People: Further Studies in the Politics of Population Leo Suryadinata, Evi Nurvidya Arifin, and Aris AnantaIndonesia's Population: Ethnicity and Religion in a Changing Political Landscape United Nations Human Settlements ProgrammeThe Challenge of Slums: Global Report on Human Settlements     

Theoretical studies on the role of food exploitation for the competition of scaamble type

Summary A model was made to clarify the basic processes of competition to occur among larvae by the exploitation as defined byBakker (1969). It was found that this model is applicable to the experimental results on the food exploitation amongDroshophila larvae obtained byBakker (1961). In the model the preimaginal stage is divided into two periods;T _f which is the time that a group of larvae spends in exhausting the food after hatching, andT _s which is the duration of the starvation period afterT _f .T _f and thenW _l (larval body weight) just after the end ofT _f are decided byF _s (amount of food supplied per larva at larval hatching) andF _c (amount of food consumed per larva).T _f affects on the onset ofT _s as well asR _l (rate of decrease in the individual body weight duringT _s ).W _a (weight of emerging adults) is gotten by a subtraction ofR _l fromW _l just after the end ofT _f ,R _e is affected directly by these components ofW _l andR _l . As a result,W _a andR _e are expressed by functions ofF _s . This model confirmed that the food exploitation lead to the competition of scramble type. Finally it was suggested that there exist some strategies which prevent ill-effects owing to the food exploitation.     

Population studies ofBrevicoryne brassicae (L.), its parasites and hyperparasites in England

Summary Studies on populations ofBrevicoryne brassicae (L.), its parasites and hyperparasites were carried out by actual counting in the sprouts field and by sticky and water traps.B. brassicae was found to be attacked by one primary parasite,Diaretiella rapae (McIntosh), which in turn is parasitized byAlloxysta brassicae (Ashm.),Asaphes vulgaris Walker,A. suspensus (Nees),Pachyneuron minutissimum (F?rster) andDendrocerus carpenterii (Curtis). The aphid population in the field was started by immigrant alates which were found flying too early to be synchronized with the sprouts plants. SimilarlyD. rapae was not synchronized with the aphids although many individuals could have been carried into a plot through parasitized immigrant alates, of which less than 30% were found parasitized. Because of high hyperparasitism (especially byA. brassicae)D. rapae was not able to maintain a high rate of parasitism to curb the aphid population growth. The maximum percentage mummies being 27.8%, while the maximum, percentage parasitism being 56.6% recorded only during the early 1974 season (mean=12.9%). The decline of aphid population from September onwards was largely due to the cold weather, Syrphid predation and occasionally fungal attack. The high rate of hyperparasitism byA. brassicae is attributed to its better synchronization withD. rapae. The mean percentage of parasite that emerged from mummies collected during 1973–74 wereD. rapae 31.3%,A. brassicae 64.3%,A. vulgaris andA. suspensus 4.3%,D. carpenterii 0.2% andP. minutissimum 0.1%.     

Book Reviews

Edward C. Green Rethinking AIDS Prevention: Learning from Successes in Developing Countries Doris Buss and Didi Herman Globalizing Family Values: The Christian Right in International Politics Alberto Alesina and Enrico Spolaore The Size of Nations David Glimp Increase and Multiply: Governing Cultural Reproduction in Early Modern England Martin King Whyte (Ed.) China's Revolutions and Intergenerational Relations Janet Rothenberg Pack Growth and Convergence in Metropolitan America Tony Barnett and Alan Whiteside AIDS in the Twenty‐first Century: Disease and Globalization Frank D. Bean and Gillian Stevens America's Newcomers and the Dynamics of Diversity A. P. Joshi, M. D. Srinivas, and J. K. Bajaj Religious Demography of India Edward Newman and Joanne van Selm (Eds.) Refugees and Forced Displacement: International Security, Human Vulnerability, and the State     

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.     

Density-dependent predation of the antLasius niger (Hymenoptera: Formicidae) on two attended aphidsLachnus tropicalis andMyzocallis kuricola (Homoptera: Aphididae)

The antLasius niger was observed collecting honeydew and preying on the two aphid speciesLachnus tropicalis andMyzocallis kuricola on the chestnut treesCastanea crenata. Observation determined how the antL. niger controlled their predation on the aphids in response to the density and honeydew-productivity of the aphids.Lachnus tropicalis was a better honeydew source thanM. kuricola forL. niger in terms of the amount of honeydew collected per unit time by the ants. The number of foraging workers on a tree increased with the number ofL. tropicalis on the tree, but not with the number ofM. kuricola. The density ofL. tropicalis perL. niger worker on a tree had a positive effect on the predation activity ofL. niger on both aphids, whereas the density ofM. kuricola per ant did not have any significant effect. The predation pressure by the ant which increased withL. tropicalis density, however, directed toM. kuricola rather than toL. tropicalis. These facts suggest (1) thatL. niger control their predation activities on aphids with regards to the densities of the attended aphids per worker, and (2) that the ants prey on the aphid species producing less honeydew. The effects of the ant predation on aphids and the importance of these predation effect in antaphids interactions were discussed.     

‘…And one for the country’ The effect of the baby bonus on Australian women’s childbearing intentions

In 2004, at a time when the nation was experiencing the lowest fertility trends in its history, the Australian Federal Government introduced the offer of a cash payment of 3,000 to all women on the birth of a new baby. The maternity payment, commonly known as the baby bonus, was increased to3,000 to all women on the birth of a new baby. The maternity payment, commonly known as the baby bonus, was increased to 4,000 in 2006 and to $5,000 in 2008. While not explicitly declared a pronatalist policy at the time of its introduction, the baby bonus was later credited with helping to halt the decline of the nation’s aggregate birth rates. This paper examines the effect of this policy on Australian women’s childbearing intentions from 2001 to 2008, using panel data from the Household, Income and Labour Dynamics (HILDA) Survey. The results indicate that the introduction of the baby bonus coincided with a statistically significant increase in women’s childbearing intentions. More specifically, the strongest increase occurred among women from lower-income households, potentially implying that the policy had the strongest effect on women who, given their current characteristics, are relatively likely to be reliant on welfare assistance to raise their children over the long term. The inferences drawn from the paper’s findings raise concern over the capacity of the baby bonus policy to reduce aggregate dependency rates.     

Resource exploitation of larvae ofGastrophysa atrocyanea Motschulsky andgalerucella vittaticollis Baly (Coleoptera: Chrisomelidae) under a limited resource condition

Summary Resource exploitation by and intraspecific competition in larvae ofGastrophysa atrocyanea andGalerucella vittaticollis were investigated in field and laboratory experiments. Larvae of both species frequently suffered from food shortages in the field. WhenG. atrocyanea larvae suffered from a food shortage, severe intraspecific competition occurred because of lack of predation and parasitism. This exploitive competition was caused by a local food shortage of the host plant. Individuals survived by fast exploitation when food became abundant (contest type competition). TheG. atrocyanea larvae were wasteful of the food resource, and no mechanism by which to economize on the utilization of the resource was acquired because of their exploitation of the abundant resource. In contrast, theG. vittaticollis population probably is regulated by extrinsic factors such as predation and parasitism. Those larvae grew into smaller adults than those ofG. atrocyanea under a food shortage, so that their wasted food consumption was lower than that ofG. atrocyanea. Although intraspecific competition was similar to that forG. atrocyanea, it was not as severe. The food forG. vittaticollis was apt to be appropriated by other wasteful exploitators such asG. atrocyanea, which was superior in resource exploitation; thereforeG. vittaticollis frequently suffered a food shortage. Consequently selection in relation to tolerance to starvation became more acute forG. vittaticollis than forG. atrocyanea, and individuals ofG. vittaticollis that could endure starvation better may have been selected.