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PubMed2002

Neurolathyrism in Ethiopia: assessment and comparison of knowledge and attitude of health workers and rural inhabitants.

A cross sectional community based study was done in the Amhara Regional State of Ethiopia in 1999-2000 to assess and compare knowledge and attitude towards neurolathyrism among health workers and the rural community. A sample of 217 health workers selected by probability proportional to size and randomly selected 589 heads of household from a rural district were interviewed using pre-tested questionnaires. Neurolathyrism was widely known among the health workers and the community. More than half of community respondents associated the disorder with walking or lying on the straw and the stalks of grass pea. In a multivariate analysis. poor neurolathyrism knowledge among the community was associated with illiteracy and with presence of a neurolathyrism patient at home. Among health workers, contact with vapour or steam of grass pea foods was the commonest cause cited. In a multivariate analysis nurses had the poorest knowledge among the health workers. Depending on the subject, health workers and community respondents had more or less knowledge than the other. The prevailing recurrent adverse climatic conditions might promote grass pea as a 'friendly' crop to the poor peasants in marginal areas who otherwise rely on it only during times of food shortages and could increase the incidence of neurolathyrism. The poor knowledge among health workers and the community and the general neglect of neurolathyrism requires urgent intervention. Appropriate strategies for the dissemination of information education, and communication (IEC) are needed.

Adolescent↗
PubMed2004

Determinants and consequences of health worker motivation in hospitals in Jordan and Georgia.

Health worker motivation reflects the interactions between workers and their work environment. Because of the interactive nature of motivation, local organizational and broader sector policies have the potential to affect motivation of health workers, either positively or negatively, and as such to influence health system performance. Yet little is known about the key determinants and outcomes of motivation in developing and transition countries. This exploratory research, unique in its broader study of a whole range of motivational determinants and outcomes, was conducted in two hospitals in Jordan and two in Georgia. Three complementary approaches to data collection were used: (1) a contextual analysis; (2) a qualitative 360-degree assessment; and (3) a quantitative in-depth analysis focused on the individual determinants and outcomes of the worker's motivational process. A wide range of psychometric scales was used to assess personality differences, perceived contextual factors and motivational outcomes (feelings, thoughts and behaviors) on close to 500 employees in each country. Although Jordan and Georgia have very different cultural and socio-economic environments, the results from these two countries exhibited many similarities among key determinants: self-efficacy, pride, management openness, job properties, and values had significant effects on motivational outcomes in both countries. Where results were divergent, differences between the two countries highlight the importance of local culture on motivational issues, and the need to tailor motivational interventions to the specific issues related to particular professional or other groupings in the workforce. While workers themselves state that financial reward is critical for their work satisfaction, the data suggest a number of non-financial interventions that may be more effective means to improve worker motivation. This research highlights the complexity of worker motivation, and the need for a more comprehensive approach to increasing motivation, satisfaction and performance, and for interventions at both organizational and policy levels.

Attitude of Health Personnel↗
PubMed2003

Primary DNA damage in chrome-plating workers.

In order to evaluate the primary DNA damage due to occupational exposure to chromium (VI), DNA strand-breaks and apoptosis in peripheral lymphocytes were measured in a group of 19 chrome-plating workers. DNA strand-breaks was assessed by alkaline (pH>13) single-cell microgel electrophoresis ('comet') assay, while apoptosis was measured by flow-cytometry after propidium iodide staining of the cells. Concentrations of chromium in urine, erythrocytes and lymphocytes were investigated as biological indicators of exposure. A group of 18 hospital workers (control group I) and another 20 university personnel (control group II) without exposure to chromium were also studied as controls. The results of the study show that chrome-plating workers have higher levels of chromium in urine, erythrocytes and lymphocytes than unexposed workers. Comet tail moment values, assumed as index of DNA damage, are increased in chromium-exposed workers and results are significantly correlated to chromium lymphocyte concentrations. No difference emerged in the percentage of apoptotic nuclei in exposed and unexposed workers. The study confirms that measurements of chromium in erythrocytes and lymphocytes may provide useful information about recent and past exposure to hexavalent chromium at the workplace. The increase in DNA strand-breaks measured by comet assay suggests this test is valid for the biological monitoring of workers exposed to genotoxic compounds such as chromium (VI).

Adult↗
PubMed2003

World Trade Center rescue worker injury and illness surveillance, New York, 2001.

BACKGROUND: The September 11, 2001, terrorist attacks on the World Trade Center in New York City, New York, prompted an unprecedented rescue and recovery response. Operations were conducted around the clock, involved over 5000 workers per day, and extended into months following the attacks. The City of New York Department of Health and Mental Hygiene and the Centers for Disease Control and Prevention implemented prospective surveillance to characterize rescue worker-related injury and illness and to help guide public health interventions. METHODS: From September 11 to October 11, 2001, personnel reviewed medical records at four Manhattan hospital emergency departments (EDs), and healthcare providers completed data collection forms at five temporary Disaster Medical Assistance Team (DMAT) facilities located at the site. Rescue workers included construction workers, police officers, firefighters, emergency medical service technicians, or Urban Search and Rescue workers. Data collected included demographic characteristics, injury type, illness, and disposition. RESULTS: Of 5222 rescue worker visits, 89% were to DMAT facilities and 12% to EDs. Musculoskeletal conditions were the leading cause of visits (19%), followed by respiratory (16%) and eye (13%) disorders. Incidence rates were estimated based on total injuries and/or illnesses reported times 200,000 (100 equivalent full-time workers in 1 year at 40 hours per week x 50 weeks per year), then divided by the total number of hours worked. Eye disorders (59.7) accounted for the highest estimated injury and illness rate, followed by headache (46.8). One death, 52 hospital admissions, and 55 transports were reported. Findings underscored the need to coordinate distribution and enforcement of personal protective equipment use, purchase of diagnostic equipment to diagnose corneal abrasions, and distribution of health advisories. CONCLUSIONS: This system provided objective, timely information that helped guide public health interventions in the immediate aftermath of the attacks and during the prolonged rescue and recovery operations. Lessons learned can be used to guide future surveillance efforts.

Adolescent↗
PubMed1999

Drug consumption in workers in France: a comparative study at a 10-year interval (1996 versus 1986).

This study compared drug consumption and associated social factors in workers in France between 1986 and 1996. The same transversal survey was performed in 1986 and 1996 using the same methodology by means of an anonymous questionnaire given to the subject and answered in the presence of an occupational physician. The 1996 population (2674 subjects) was found to be older (37.0 +/- 9.8 versus 35.7 +/-10.2 years) and to take more drugs (+5.1%) than the population of 1986 (2221 subjects). There were fewer manual workers in the 1996 population. In both periods, women used significantly more drugs in general and more psychoactive (mainly anxiolytic), cardiovascular, endocrine metabolic, and homeopathic drugs than men. The mean value of estimated difficulty of work was higher in subjects taking drugs in general, and especially those taking hypnotic, anxiolytic, psychoactive, antiinflammatory, and digestive drugs in 1986 as well in 1996. In 1986 as well as in 1996, manual workers took no more drugs than did nonmanual workers in general, except for analgesic and antiinflammatory drugs. Nonmanual workers used homeopathic drugs more than manual workers. The presence of extraprofessional problems was associated with an increase in consumption of drugs in general and psychoactive, hypnotic, anxiolytic, antiinflammatory, cardiovascular, digestive, and endocrine metabolic drugs in particular, in 1986 as well as in 1996. After adjustment for variables linked to drug use, there was no significant change in total drug consumption in general but a significant decrease in psychoactive (-49%) (mainly hypnotic [-71%]), and digestive (-39%) drug consumption in this population between 1986 and 1996. In contrast, analgesic use significantly increased (+36%). This study underscores the high level of drug consumption in workers (more than 40% of the subjects were taking drugs). Although there were no quantitative changes, marked qualitative modifications were found with a decrease in consumption of psychoactive (and mainly hypnotic) and digestive drugs and an increase in analgesic drug use between 1986 and 1996. Thus, specific drug information programs designed to reduce psychoactive drug consumption and to favor analgesic drugs for better pain management seem to have been (at least partly) followed. The study also underscores the importance of some social factors associated to general and specific drug use (mainly difficulty of work and presence of extraprofessional problems, and to a lesser extent, kind of work). Their weight remained similar in 1986 and 1996.

Adult↗
PubMed1997

Abnormal DNA repair activities in lymphocytes of workers exposed to 1,3-butadiene.

Exposure to high concentrations of butadiene has been shown to cause cancer among exposed workers. We have conducted a biomarker study to elucidate whether current butadiene exposure conditions are hazardous to workers. Twenty-four workers exposed consistently to butadiene were matched with 19 co-workers who had much less contact with butadiene and who served as our controls. In the standard cytogenetic assay, there was no difference in chromosome aberration frequencies between the exposed and control groups. In the challenge assay, the exposed group shows a consistent, but non-significant, increase in chromosome aberrations indicating some abnormality in DNA repair response. The observed dicentric frequency in the challenge assay (indicative of abnormal repair of damaged chromosomes) is significantly correlated with a butadiene metabolite, 1,2-dihydroxy-4-(N-acetylcysteinyl)butane, in urine (r = 0.52; p = 0.04). Furthermore, cigarette smokers had consistently abnormal repair response compared with non-smokers for both the control and exposed groups. A small subset of the studied workers were evaluated for toxicant-induced DNA repair deficiency using an independent cat-host cell reactivation (CAT-HCR) assay. When cigarette smokers and non-smokers were combined in our analysis, we observed that the exposed group (n = 9) had a significant reduction of DNA repair activities (p = 0.009) compared with the control group (n = 6). Cigarette smoking contributed significantly to the effect as exposed smokers (n = 4) had a significant reduction in DNA repair activities (p = 0.04) compared with exposed non-smokers. The results from the two independently conducted assays support each other and confirm the previously reported abnormal DNA repair response in another group of butadiene workers. In conclusion, our data indicates that exposure to environmental toxicants, such as butadiene, can cause DNA repair defects. Therefore, the current butadiene exposure conditions are still hazardous to workers. However, our data indicates that butadiene is not a potent genotoxic agent. Furthermore, the butadiene-induced effect is significantly enhanced by the cigarette smoking habit.

Adult↗
PubMed2002

Lead exposure and urinary N-acetyl beta D glucosaminidase activity in adolescent workers in auto repair workshops.

PURPOSE: To investigate levels of lead (Pb) exposure and renal tubular damage among adolescent workers in auto repair workshops in Turkey. METHODS: The study was conducted on 39 adolescent workers (mean age: 16.18 +/- 3.19 years) in auto repair workshops (8 autoelectrician, 10 motor repairman, 8 auto painter, 5 turner, 8 bonnet straighter). Thirteen adult employees of battery production in the workshops (mean age: 32.08 +/- 10.94 years) and 29 healthy rural adolescent (mean age: 14.78 +/- 2.68 years) constituted the control groups. The level of blood Pb was investigated by an atomic absorption spectrophotometer and urinary N-acetyl beta- D glucosaminidase (NAG) activity was measured by a colorimetric method. Mann-Whitney U test was performed to examine group differences. RESULTS: All subjects and controls had normal blood urea, creatinine, uric acid, sodium, potassium levels, normal routine urine examination and tubular phosphorus reabsorption. Blood Pb levels in auto repair workers (8.13 +/- 7.41 mug/dL) were significantly higher than the rural control group (3.49 +/- 1.39 mug/dL) but lower than the battery workers (25.27 +/- 9.82 mug/dL). Urinary NAG (U/gr creatinine) (4.71 +/- 2.11) was lower than the battery workers (7.39 +/- 4.37), however significantly higher than the normal control group (3.07 +/- 1.20). In addition, auto painters had higher levels of Pb exposure and urinary NAG activity than the other workers (p <.05). CONCLUSION: Chronic low dose Pb exposure was found to cause renal tubular injury in children workers of auto repair workshops.

Acetylglucosaminidase↗
PubMed2000

Increased lymphocyte DNA strand breaks in rubber workers.

OBJECTIVE: To study the effect of occupational exposure to rubber processing, smoking, and alcohol drinking on lymphocyte DNA damage. SUBJECTS AND METHODS: Of 371 employees (197 men and 174 women) from a rubber factory in Guangzhou, 281 were rubber processing workers from five production sections and 90 were managerial workers. Information on occupational exposure, smoking, and drinking was collected by interviews. Blood samples were taken in the morning by venipuncture. DNA damages were measured by the Comet assay. Possible DNA-protein crosslinks were broken down by proteinase K. Tail moment, measured by Komet 4.0 image analysis software, was the measure of DNA damage. RESULTS: The rubber processing workers had larger tail moment than the managerial workers (Geometric mean, 95%CI) [1. 77microm (1.64-1.90) versus 1.52microm (1.36-1.71), P=0.04]. Both smoking [1.93microm (1.74-2.13) versus 1.59microm (1.47-1.71), P=0. 003] and alcohol drinking [2.21microm (1.87-2.62) versus 1.63microm (1.53-1.74), P<0.001] increased tail moment. Tail moment differed significantly among job categories (F=3.21, P=0.008), the largest was observed in mixers. In the non-smoking and non-drinking workers, rubber processing workers had larger tail moment than managerial workers after adjusting for age (P=0.033). General linear model analysis showed that after adjusting for each other, occupational exposure (P=0.027), smoking (P=0.012), and alcohol drinking (P=0. 013) was associated with larger tail moment, whereas age and gender had no effect. CONCLUSIONS: Occupational exposure to rubber processing, smoking, and alcohol drinking can cause DNA damage.

Comet Assay↗
PubMed1998

Cytogenetic biomonitoring of workers exposed to bitumen fumes.

Bitumen samples and fumes consist essentially of polycyclic hydrocarbons (PAH) and their derivatives, some of which are known to be carcinogenic or co-carcinogenic in animals. The level of total PAH is low when compared with coal-tar products. There is very limited data on possible health risk from exposure to bitumen fumes in workers. In this study, sister-chromatid exchange (SCE), micronuclei (MN) and high frequency of SCE cells (HFCs) were determined for 28 workers exposed to bitumen fumes and 28 control subjects. Urinary 1-hydroxypyrene (1-OHP) excretion was used as a biomarker of occupational exposure to PAH. The mean value of 1-OHP excretion of workers was 0.78+/-0.46 micromol/mol creatinine and for controls 0.52+/-0.44 micromol/mol creatinine (p<0.05). The mean values of SCE per cell and the frequency ( per thousand) of MN in peripheral lymphocytes from the workers and controls were 5.13+/-0. 64, 4.71+/-0.67, and 2.25+/-0.42, 1.79+/-0.32 respectively (p<0.05, p<0.0001). The mean value of HFCs for workers and controls were 7. 85+/-2.3 and 7.05+/-3.16, respectively (p>0.05). Our data reveal that bitumen fumes during road paving operations are absorbed by workers and that bitumen fume exposure is able to significantly induce cytogenetic damage in peripheral lymphocytes of workers after controlling some possible confounding factors, such as age, sex and smoking habits.

Adult↗
PubMed2005

Core groups and the transmission of HIV: learning from male sex workers.

A growing and substantial body of research suggests that female sex workers play a disproportionately large role in the transmission of HIV in many parts of the world, and they are often referred to as core groups by epidemiologists, mathematical modellers, clinicians and policymakers. Male sex workers, by contrast, have received little attention and it is not known whether it is helpful to conceptualize them as a core group. This paper draws upon ethnographic research documenting social and sexual networks in London and looks at the position of five male sex workers within a network comprising 193 men and seven women (as well as 1378 anonymous sexual contacts and 780 commercial contacts). In so doing, it suggests that there is no evidence to show that male sex workers are more or less likely to acquire or transmit HIV in the course of commercial sex compared with other types of sexual relationships. In addition, men engaging in non-commercial sex all reported having unprotected sex in a variety of contexts and relationships and there is no evidence to suggest that men who are not sex workers play less of a role in the transmission of HIV. In short, these data suggest that it would be inappropriate to conceptualize male sex workers as a core group. This is not to suggest that public policy should continue to overlook male sex workers. New and inventive approaches are required to reach out to a vulnerable but diverse group of men, selling sex for a variety of reasons; even if these men are no more vulnerable to acquiring and/or transmitting HIV than other men and women that form part of their network.

Adult↗
PubMed1997

Reproducibility and validity of oral visual inspection by trained health workers in the detection of oral precancer and cancer.

A randomized intervention trial is in progress in Kerala, India, to evaluate the effectiveness of oral visual inspection by trained health workers (HWs) in the prevention of oral cancer. Fourteen health workers with college graduation as the basic qualification were trained in oral visual inspection to identify oral cancers and precancers among the participants of the screening trial and to refer them for further confirmation and management. The aim of the present study was to evaluate the reproducibility and validity of the screening test provided by the health worker against the reference oral visual findings of three physicians. A total of 2069 subjects who had already been examined were re-examined by the health workers and physicians. The sensitivity and the specificity of the oral visual inspection were 94.3% and 99.3% respectively. There was moderate agreement between the findings of the initial and the repeat mouth examinations carried out by the health workers, which were on average 6 months apart. There was almost perfect agreement (kappa = 0.85) between the findings of the health workers and the physicians in identifying the different types of oral precancerous lesions. The findings of our study indicate that it is possible to train resource persons to perform the oral cancer screening test as accurately as doctors, although experience appears to be a crucial component of health workers' accuracy. The efficacy of such an approach to reduce the incidence of and mortality from oral cancer, however, remains to be proven.

Education↗
PubMed2001

Domestic violence: a comparative survey of levels of detection, knowledge, and attitudes in healthcare workers.

The objective of this study was to compare the knowledge, attitudes, responses and levels of detection of domestic violence among a variety of healthcare workers in different specialities.Self-administered questionnaires were sent to community and hospital based healthcare workers in Oxfordshire working in primary care, obstetrics and gynaecology, mental health and accident and emergency. These comprised all principal general practitioners and general practitioner registrars, 50% of practice/district nurses and health visitors in each practice, and all healthcare workers in obstetrics and gynaecology, community mental health teams and accident and emergency in one trust. The amount of domestic violence detected in different healthcare settings was far less than indicated by anonymous surveys and crime figures. Knowledge about many of the issues surrounding domestic violence was inconsistent and there were fundamental deficiencies. The attitudes of healthcare workers to domestic violence were generally sympathetic and supportive. Women, nurses and community mental health workers reported significantly better knowledge and more positive attitudes than other respondents. Gender, role and speciality were independently associated with more positive attitudes and the latter two were independently associated with good knowledge. The response that healthcare workers make when they uncover domestic violence is confused and often inappropriate. In conclusion, most healthcare workers accept that domestic violence is a healthcare issue but lack fundamental knowledge about the issues surrounding domestic violence itself and appropriate agencies that can offer help. They also lack skills in identifying and discussing this issue with patients/clients. A large, unfulfilled training need has been identified.

Attitude of Health Personnel↗
PubMed2003

Air concentrations and urinary metabolites of polycyclic aromatic hydrocarbons among paving and remixing workers.

The exposure of paving workers to polycyclic aromatic hydrocarbons (PAH) during stone mastic asphalt (SMA) paving and remixing was evaluated. The effects on the workers' PAH exposure were also evaluated during the use of an industrial by-product, coal fly ash (CFA), instead of limestone as the filler in the SMA. The PAH exposure was measured by personal air sampling and by analysing the levels of urinary naphthols, phenanthrols and 1-hydroxypyrene (1-OHP) in the workers' pre- and post-shift urine samples. The respiratory PAH exposure of the paving workers (geometric mean (GM) 5.7 microg m(-3)) was about ten-fold that of the traffic controllers (GM 0.43 microg m(-3)). The levels of PAH metabolites were significantly higher (p < 0.05) in the post-shift urine samples than in the pre-shift urine samples, and the levels of metabolites in the post-shift urine of paving workers were significantly higher than in that of the controls (p < 0.01). Urinary 1-naphthol correlated well with the airborne concentrations of the two- to three-ring PAHs (r = 0.544, p = 0.003) and naphthalene (r = 0.655, p < 0.001), when non-smoking paving workers were tested. A good correlation was observed between urinary 1-OHP and the airborne concentrations of the four- to six-ring PAHs (r = 0.524, p = 0.003) as well as total PAHs (r = 0.575, p = 0.001). The concentrations of 1-OHP and phenanthrols in the urine of the pavers were significantly higher (p < 0.01) during remixing than during SMA paving. The CFA in the asphalt had no effect on the airborne PAH exposure or on the concentrations of the PAH metabolites in the paving workers' urine.

Adult↗
PubMed2002

Male production in stingless bees: variable outcomes of queen-worker conflict.

The genetic structure of social insect colonies is predicted to affect the balance between cooperation and conflict. Stingless bees are of special interest in this respect because they are singly mated relatives of the multiply mated honeybees. Multiple mating is predicted to lead to workers policing each others' male production with the result that virtually all males are produced by the queen, and this prediction is borne out in honey bees. Single mating by the queen, as in stingless bees, causes workers to be more related to each others' sons than to the queen's sons, so they should not police each other. We used microsatellite markers to confirm single mating in eight species of stingless bees and then tested the prediction that workers would produce males. Using a likelihood method, we found some worker male production in six of the eight species, although queens produced some males in all of them. Thus the predicted contrast with honeybees is observed, but not perfectly, perhaps because workers either lack complete control or because of costs of conflict. The data are consistent with the view that there is ongoing conflict over male production. Our method of estimating worker male production appears to be more accurate than exclusion, which sometimes underestimates the proportion of males that are worker produced.

Animals↗
PubMed1996

[Cancer of the oral cavity in machine workers].

BACKGROUND: So far, only few studies exist which investigated the influence of occupational factors on the risk of oral cancer. PATIENTS: A case control study enrolling 100 patients with carcinomas of the oral cavity and 400 randomized control persons was performed to analyze occupational risk factors for oral cancer. RESULTS: Twenty-two percent of the tumor patients and only 8.5% of the control persons were employed as machine workers. The relative risk for squamous cell carcinoma of the oral cavity was 3.4 (K.I.: 1.7-7.0) for machine workers (adjusted for alcohol and tobacco). Single case analysis showed that 96.3% of the machine workers with oral cancer and only 17.3% of the machine workers in the control group were exposed to dust, especially metal dust (55.5% vs. 9.7%). Also the exposure to paint, lacquer, and varnish containing chromium and nickel was significantly higher in machine workers with cancer of the oral cavity than in the machine workers without cancer (29.6% vs. 10.9%). CONCLUSIONS: The findings suggest that exposition to various types of dust, especially metal dust, increases the risk of oral cancer in machine worker patients.

Adult↗
PubMed2002

Willingness to pay to avoid sharps-related injuries: a study in injured health care workers.

BACKGROUND: Injuries caused by sharp medical devices are common among health care workers and may result in the transmission of human immunodeficiency virus and hepatitis C virus. OBJECTIVE: The direct medical costs associated with treating these injuries are well characterized but fail to capture the costs of such intangible factors as worker anxiety and distress. The objective of this study was to estimate these intangible costs. SUBJECTS: Subjects included health care workers reporting sharps-related injuries to 2 hospital occupational health services. METHOD: A contingent valuation approach was used to assess willingness to pay to avoid sharps-related injuries among recently injured health care workers. Workers were presented with the option of paying out of pocket for a hypothetical injury-prevention device. The median amount of money subjects were willing to pay was estimated with logistic regression, and multivariable regression was performed to assess confounding by worker characteristics and circumstances surrounding injuries. RESULTS: Study interviews were conducted for 116 subjects; median time from injury to interview was 3 days (range, 0-15). Most subjects were women (73%), and most were nurses (44%) or trainees (32%). The crude median amount subjects were willing to pay to avert injury was $850 (US); when adjusted for patient risk status (human immunodeficiency virus and hepatitis C virus status), and working with an uncooperative patient at the time of injury, median amount increased to $1270. CONCLUSION: The high median amount subjects were willing to pay to avoid a sharps-related injury suggests that the costs of "intangible" aspects of worker injury, such as anxiety and distress, may equal costs associated with the medical evaluation of these injuries. These costs should be incorporated in economic analyses of sharps-injury prevention.

Adult↗
PubMed2005

Juvenile hormone, reproduction, and worker behavior in the neotropical social wasp Polistes canadensis.

Previous studies of the division of labor in colonies of eusocial Hymenoptera (wasps and bees) have led to two hypotheses regarding the evolution of juvenile hormone (JH) involvement. The novel- or single-function hypothesis proposes that the role of JH has changed from an exclusively reproductive function in primitively eusocial species (those lacking morphologically distinct queen and worker castes), to an exclusively behavioral function in highly eusocial societies (those containing morphologically distinct castes). In contrast, the split-function hypothesis proposes that JH originally functioned in the regulation of both reproduction and behavior in ancestral solitary species. Then, when reproductive and brood-care tasks came to be divided between queens and workers, the effects of JH were divided as well, with JH involved in regulation of reproductive maturation of egg-laying queens, and behavioral maturation, manifested as age-correlated changes in worker tasks, of workers. We report experiments designed to test these hypotheses. After documenting age-correlated changes in worker behavior (age polyethism) in the neotropical primitively eusocial wasp Polistes canadensis, we demonstrate that experimental application of the JH analog methoprene accelerates the onset of guarding behavior, an age-correlated task, and increases the number of foraging females; and we demonstrate that JH titers correlate with both ovarian development of queens and task differentiation in workers, as predicted by the split-function hypothesis. These findings support a view of social insect evolution that sees the contrasting worker and queen phenotypes as derived via decoupling of reproductive and brood-care components of the ancestral solitary reproductive physiology.

Aging↗
PubMed1974

Were workers of eusocial hymenoptera initially altruistic or oppressed?

Studies of a primitively eusocial halictid bee, Lasioglossum zephyrum, strongly suggest that a major factor in originating a worker caste is selection at the individual level for queens that control associated adult females. Even in this scarcely social form, the queen inhibits other adult females from becoming queens, perhaps by her high level of activity and frequent nudging in the nest. Queens are behaviorally less varied than workers and show specialization, particularly in frequency of nudging (which is concentrated on the worker with largest ovaries) and of backing. Backing draws workers, especially those with slender ovaries, down to lower parts of the burrows where the stimuli for cell construction and provisioning probably operate. Eating of worker-laid eggs by queens was also noted. In spite of the suggestion that queens have evolved to control their workers rather than that workers have evolved to help their queens, both may well have occurred, for these processes are not mutually exclusive; moreover, social attributes mutually beneficial to both castes no doubt have arisen.

Journal Article↗