A ten-year study of population dynamics of citrus pests in the pesticide-reduced orchard

Summary To determine the effectiveness of a pest management system that uses pesticides at a low level, we censused populations of seven insect pests and three plant diseases from 1980 to 1989 in a citrus orchard which was managed with a pesticide-reduced and pesticide-free protocols, in Wakayama Prefecture, Japan. In the orchard, we controlled the pests solely by spraying petroleum oil once a year from 1980 to 1985, by not spraying insecticide in 1986, and spraying only germicide in 1987. The arrowhead scale population remained much lower level at which citrus trees begin to wither when petroleum oil was sprayed, whereas it rapidly increased and began to wither trees during the years without spraying petroleum oil. The Indian wax scale population rapidly increased only during a 2-year period and then declined. Although the infection level of the sooty mold was unusually high on the trees where the density of the scale was high, this pathogen did little damage to citrus trees. The population of the red wax scale gradually increased throughout the census period but did not reach the level at which citrus trees begin to be damaged. Other pests also caused negligible damages to citrus trees. The results indicated that the pesticide-reduced pest management system which was proposed by Inoue and Ohgushi (1976, 1977) is valid for the prevention of the outbreak of the arrowhead scale, and that is has the sufficient control efficiency for the other pests in citrus orchards. Contribution to the ecological studies of scale insect 3.     

A probability sample of gay males

Data are presented from a national probability sample of males interviewed by telephone and asked their sexual orientation. Of these males 3.7 percent reported that they were homosexual or bisexual. Homosexual/bisexual men were compared with heterosexual ones on the demographic variables. This sample produced larger numbers in those groups which appear to be underrepresented in the usual samples drawn from the gay world. These groups include those with little education, married men, older men, minorities, and those living in small towns. It is suggested that probability samples which do not draw directly or heavily from the gay world for homosexual respondents obtain a broader sampling of those having homosexual feelings or behaviors.     

The sterile release method for population control with interspecific competition

Summary A differential equations model of competing species with the release of sterile individuals of one of the species is examined. The system is found to have two positive steady states for certain parameter values; one of these is stable and the other is unstable. The system is quite resilient around the stable steady state. The release of steriles causes the nontarget species to increase in numbers. There exists a value of the release rate above which the pest species collapses to extinction. The existence of the competitor species assists the sterile release program since the pest equilibrium at any release rate is lower with the competitor species present than without it; in addition the release rate required to cause collapse of the pest species is lower with the competitor species present than without it. The effects of the parameters on the ease of eradication were examined. It was found that the ideal competitor species should have a high rate of increase, a large carrying capacity and exert strong competitive depression on the pests. The ideal pest would have a low rate of increase, a low carrying capacity and be a poor competitor.     

Combining pheromone-baited and food-baited traps for insect pest control: Effects of developmental period

Summary An age-structured population dynamics model is presented that incorporates pheromone-trapping and food-trapping as control methods for an insect pest. The model yields the following results. Low rates of pest survivorship allow lower trapping rates for control. Species with long developmental periods are easier to control than those with shorter developmental periods (other factors being equal) due to lower net survival. The rates of pheromone trapping alone for effective control are usually very high. The combination of pheromone and food trapping allows control with much lower trapping rates than either method alone. Even small amounts of immigration of adult pests into the control area renders pheromone control ineffective, whereas food traps suppress both the immigrants and the resident population. Food- (or odor-) baited traps which attract both males and females are only somewhat more efficient than those which attract females alone. The existence of density-dependent population regulation assists the control program substantially, but this assistance declines as food trapping becomes a more important part of the control program. Larval competition strongly affects the required trapping rates for eradication; species in which all larvae exert strong competition are much easier to control than those in whic the younger larvae contribute little to the total competitive depression.     

Modelling the effects of population aggregation on the efficiency of insect pest control

Summary A methodology is developed to assess the effects of spatial distribution on the efficiency of insect pest control. This methodology is especially applicable to pest control methods whose efficiency of action depends either positively or negatively on pest density It is applied here to the sterile insect technique and pheromone trapping for male annihilation, which both depend negatively on density. This methodology relies on quantifying clumps of various size and then relating this to efficiency of control and predicting the total pest production given the information on clump sizes and efficiency of control for each clump size. It is found that control is about four times as difficult for a population that is highly clumped (k of the negative binomial distribution=0.25) as for a regularly dispersed population.     

Thirty-Five Years After Stonewall: An Exploratory Study of Satisfaction with Police Among Gay,Lesbian, and Bisexual Persons at the 34th Annual Atlanta Pride Festival

ABSTRACT

The gay rights movement began in the summer of 1969 when gay men rioted against police for raiding a bar known as the Stonewall Inn. In the succeeding 35 years, very little research has explored the relationship between police organizations and gay, lesbian, bisexual, and transgendered (GLBT) communities. The purpose of this study is to describe the attitudes that GLBT persons currently hold toward police. Subjects were sampled from the 34th Annual Atlanta Pride Festival and asked to complete a self-administered questionnaire. Of the 179 GLBT participants, the vast majority reported high satisfaction with community policing practices at this event. Moreover, age, household income, victimization, security presence, and identification with gay-themed media significantly predicted attitudes toward police.     

Perspective of practical biological control and population theories

We have not yet had sufficient theoretical explanation for successful biological control in which a key pest is controlled after an introduction of natural enemies. I compare here real features of successful biological control and theoretical host–parasitoid population models to reduce the gap between theory and practice. I first review the historical interaction between classical biological control projects and theoretical population models. Second, I consider the importance of host refuges in host–parasitoid population dynamics as concerns the mechanisms of low and stable host density. The importance of density–dependent parasitism through parasitoid reproduction in multivoltine host–parasitoid systems and supplemental generalist natural enemies are also discussed. Finally, I consider the difference in tactics for classical biological control and for augmentation of natural enemies in annual crop systems. Received: December 20, 1998 / Accepted: January 15, 1999     

Mental health issues: a comparison of lesbian, bisexual and heterosexual women

This study examines mental health issues among women of different sexual orientations. An anonymous survey was administered at 33 health care sites across the United States; the sample (N = 1304) included lesbians (n = 524), bisexual (n = 143) and heterosexual women (n = 637). Not only did sexual orientation influence the probability of experiencing emotional stress, but also whether a bisexual woman or lesbian had disclosed her sexual orientation (was "out") impacted the likelihood of having or having had mental health problems. Bisexual women and lesbians experienced more emotional stress as teenagers than did heterosexual women. Bisexual women were more than twice as likely to have had an eating disorder compared to lesbians. If a bisexual woman reported being out she was twice as likely to have had an eating disorder compared to a heterosexual woman. Lesbians who were not out and bisexual women who were out were 2-2.5 times more likely to experience suicidal ideation in the past 12 months. Lesbians and bisexual women who were not out were more likely to have had a suicide attempt compared to heterosexual women. Lesbians used psychotherapy for depression more commonly than did heterosexual or bisexual women. This is one of the few studies that compares lesbians, bisexual and heterosexual women. The implications of these findings are discussed.     

Management sampling for larvae of the colorado potato beetle

Summary Untreated plot of ‘Kennebec’ and ‘Superior’ potatoes were sampled for Colorado potato beetle (CPB) at L'Assomption, Quebec, in 1982, 1986 and 1987. Numbers of CPB larvae per stalk were counted on 74 occasions for sample sizes ranging from 50 to 200 stalks. Regression techniques were used to estimate the relationship between mean and cumulative proportion of stalks infected. These were used to set up binomial sequential probability ratio test (SPRT) sampling plans for pest management decision making with tally numbers (or tally thresholds, cutoff numbers) equal to 0,1,...10. A binomial scheme defined by tally number equal to 4 is proposed for general use, and corresponding plans are given, with estimated operating characteristic and average sample number curves.     

Internalized Homophobia,Coping, and Quality of Life Among Nigerian Gay and Bisexual Men

ABSTRACT

Despite high levels of homophobia in Nigeria, no studies have investigated the quality of life (QOL) of Nigerian gay and bisexual (GB) men. The associations between QOL and minority stress may differ from those reported in developed countries and may indicate alternative interventions. This study investigated internalized homophobia (IH) and coping strategies among gay and bisexual men in Nigeria and the relationships with overall QOL. Eighty-nine GB men were recruited with a snowball sampling technique. QOL (outcome), IH (predictor) and coping strategies (covariates) were assessed using standardized questionnaires. Relationships were investigated using linear regression analyses. Participants used adaptive more frequently than maladaptive coping strategies. The relationship between IH and QOL was nonlinear (β = ?0.27, 95% CI = ?0.48, ?0.06), and the positive component was attenuated by adaptive coping strategies. Adaptive strategies can be reinforced as a therapeutic intervention to improve wellbeing among gay and bisexual men in Nigeria.     

Comparison of life tables between the solitary eumenid waspAnterhynchium flavomarginatum and the subsocial eumenid waspOrancistrocerus drewseni to evaluate the adaptive significance of maternal care

Summary I compared life tables between the solitary eumenid waspAnterhynchium flavomarginatum Smith and the subsocial eumenid waspOrancistrocerus drewseni Saussure in Kyoto, Japan, during 1980–1983. The subsocial eumenid is parthenogenetic in this study area. There were 9 identified mortality factors in the solitary eumenid and 7 in the subsocial eumenid, 6 of which were common to the two eumenids. The important differences of mortality between the two eumenids were seen in the egg, larval, and prepupal stages. In the egg stage, mortality by the phorid flyMegaselia sp. was much lower in the subsocial eumenid (1.4%) than in the solitary eumenid (15.0%) likely because of the matenal care of the subsocial eumenid (progressive provisioning and other related behavior), which reduced predation pressure. In the larval stage, mortality by the miltogrammine flyAmobia distorta was also lower in the subsocial eumenid (8.1%) than in the solitary eumenid (23.8%) also probably because of the maternal care of the subsocial eumenid. A comparison of mortality in the two eumenids between the stable, long continuing natural nest sites and the additional temporal ones showed that the phorid fly remained near its birth place and parasitized stable nest sites. The miltogrammine fly followed returning eumenid wasps and parasitized those nest sites that have a high host density. In the prepupal stage, mortality by endogenous death was higher in the subsocial eumenid than in the solitary eumenid. Mortality due to the rhipiphorid beetle was also higher in the subsocial eumenid probably due to more frequent flower-visits by the subsocial eumenid. The defense mechanism of the subsocial eumenid was discussed in relation to the evolution of subsociality. Contribution to the ecological studies of the eumenid wasps. I.     

A host shift from wild blue cohosh to cultivated potato by the phytophagous ladybird beetle, Epilachna yasutomii (Coleoptera, Coccinellidae)

Life history traits of the phytophagous ladybird beetle Epilachna yasutomii were compared between a nonpest population feeding on wild blue cohosh and a pest population feeding on cultivated solanaceous crops, mainly potato. Newly emerged adults of the nonpest population entered diapause early in midsummer when blue cohosh withered, while adults of the pest population were found in tomato and eggplant fields until late autumn. The pest population had larger females, a higher population growth rate, a shorter larval developmental period, and reduced longevity of overwintered females, compared with the nonpest population. ANOVA indicated that all these life history traits were influenced by the food plant, and that the number of eggs laid per female and the longevity of overwintered females were also affected by the population type. These findings suggest that the life history pattern of E. yasutomii changed to high fecundity with a short life span from low fecundity with a long life span as a result of the host shift from wild blue cohosh to cultivated solanaceous crops. Received: May 22, 1998 / Accepted: January 13, 1999     

Models for mating disruption by means of pheromone for insect pest control

Models are presented to investigate the population dynamic behavior of a pest population with the release of pheromone for mating disruption. Three mechanisms of mating disruption are considered: (i) confusion of males, (ii) competition with female pheromone trails yielding false trail following, (iii) emigration of males prior to mating. In addition, several refinements to confusion are considered. Confusion and emigration of males were found to be very similar both quantitatively and dynamically; also, a combination of both mechanisms was very little more efficient than either one separately. False trail following is difficult to compare with the other two, since competition with wild females is involved and thus the total population size enters the equations. Density dependence of the action of pheromones results in some cases in which mating disruption cannot control the pest population. Similarly, aggregation of the pest population decreases the efficiency of the method unless the pheromone action is density independent. Delayed mating of females makes control easier, and may constitute one mechanism for mating disruption.     

Pareto improving transition from a pay-as-you-go to a fully funded pension system in a model of endogenous growth

In this paper we investigate the possibility of Pareto improving social security reforms within a framework of endogenous growth. Belan et al. (1998) propose a transition from a pay-as-you-go (PAYG) pension system to a system of savings–subsidization. We follow this approach and prove that a Pareto improving conversion from the PAYG system to a fully funded one is possible. Finally, we compare the subsidy system with the fully funded system and discuss the problem of implementing the transition to the fully funded system. Received: 07 March 1999/Accepted: 13 December 1999     

Population growth and social security financing

By allowing the population growth to be flexible, this paper analyzes the effect of a tax reform that involves an introduction of consumption taxation for social security financing. It is found that population growth and labor supply play an important role in determining the effect of the tax reform. If population growth and labor supply are exogenous, then an introduction of a consumption tax for social security financing, with the payroll tax rate being endogenous, decreases the interest rate and increases capital accumulation. However, if population growth and labor supply are endogenous, then an introduction of a consumption tax for social security financing increases the interest rate and reduces capital accumulation. Received: 26 February 2001/Accepted: 26 August 2001     

The Myth of Openness and Secrecy in Intimate Relationships: The Case of Spouses of Mixed-Orientation Marriage

The phenomenon of mixed-orientation marriages, in which one of the partners is straight and the other is non-straight, is invisible, yet not insignificant. Focusing on gay and bisexual men who are married to straight women, this article was designed to explore one of the essential themes in their relationship: the dynamics between secrecy and openness regarding the men’s sexual orientation and gay practices. Based on the phenomenological paradigm, 38 men and eight women of mixed-orientation marriages in Israel were interviewed and shared their subjective life reality. Six patterns of secrecy and openness were identified, including complete secrecy, conspiracy of silence, initiated concealment (of the husband and wife), disloyalty/violation of the agreement, selective sharing, and complete openness. The findings challenge the idea that secrecy is detrimental and openness is beneficial in the context of mixed-orientation marriages. Findings are discussed within the framework of the dialectical approach.     

Use of a telephone screener to identify a probability sample of gays, lesbians, and bisexuals

OBJECTIVES: To examine public response to a telephone screener used to identify a probability sample of lesbians, gays, and bisexuals. METHODS: A telephone screener was designed to provide a representative sample of self-identified lesbians, gays, and bisexuals (LGB) in the 30 central cities of the 15 largest Consolidated Metropolitan Areas. RESULTS: Of 14,458 households contacted, 11,612 completed at least part of the survey. Of these, only 2.6% refused or responded "don't know" to the sexual orientation screener question. Respondents from the northeast were more reluctant to answer than respondents from the west. CONCLUSIONS: The use of a screener on a national telephone survey to screen households for self-identified lesbian, gay, and bisexual adults was a successful way to generate a representative sample.     

Estimation of the individual number entering each development stage in an insect population

Summary A method for estimating the number entering each development stage from data obtained by regular sampling through one generation of an insect population was described. This method is consisted of the following two procedures: The provisional estimates are calculated on the assumption that each stage has a common mortality in a sampling interval. Then these estimates are corrected on another assumption that the mortality is different in each stage but constant during a stage. The result of testing its validity with two laboratory populations of the common cabbage butterfly,Pieris rapae crucivora, showed the availability of the present method.     

Social security, public education, and growth in a representative democracy

This paper studies the relationship between public education and pay-as-you-go social security in a representative democracy, where the government reacts both to voting and lobbying activities of workers and pensioners. While an intergenerational conflict prevails concerning actual social security contributions, workers may prefer public education for its positive effect on later pension benefits. Population aging diminishes the relative lobbying power of pensioners, leading to a higher contribution rate, educational expansion, and higher per capita income growth. Received: 05 April 1999/Accepted: 20 December 1999     

Intimate Partner Violence Among Sexual Minorities in Japan: Exploring Perceptions and Experiences

Using qualitative interviews (n = 39) and participant observation (n = 54), this study documents perceptions and experiences of violence between lesbian, gay, bisexual, transgender, and intersex intimate partners in Japan, thereby providing exploratory, formative data on a previously unexamined issue. Results indicate that intimate partner violence (IPV) is experienced physically, sexually, and psychologically in all sexual minority groups. Participants perceived the violence to be: a) very similar to heterosexual IPV against women; b) more likely perpetrated and experienced by lesbians, bisexual women, and transgender persons compared to gay and bisexual men and intersex persons; c) the cause of several negative physical and mental health outcomes; and d) largely unrecognized in both sexual minority communities and broader Japanese society.