Untreated Workers Research Articles

Mandated Rest Breaks and Occupational Injuries and Illnesses in Dallas County, Texas Construction Workers: A Quasi-Experimental, Comparative Interrupted Time Series Study.

We estimated associations of a rest break ordinance, implemented for construction workers in Dallas, Texas in 2016, with workplace injuries and illnesses. We used workers' compensation claims data to compare changes in rates of injuries and illnesses among Dallas County, Texas construction (ie, "treated") workers with changes in untreated workers, before (2013-2015) and after (2016-2018) a rest break ordinance was implemented. Immediately after the ordinance was implemented, rates of injuries/illnesses among treated workers were modestly lower than in comparison workers (rate ratio comparing postmandate vs premandate rates, treated vs comparison workers: 0.89, 95% confidence interval: 0.72-1.11). Postordinance versus preordinance slope trends were similar in the treated versus the comparison group. Ten-minute rest breaks were associated with modestly lower rates of workplace injury/illnesses. More comprehensive standards may be needed for protection.

Inhibition of HSP90 causes morphological variation in the invasive ant Cardiocondyla obscurior.

Canalization underlies the expression of steady phenotypes in the face of unsteady environmental conditions or varying genetic backgrounds. The chaperone HSP90 has been identified as a key component of the molecular machinery regulating canalization and a growing body of research suggests that HSP90 could act as a general capacitator in evolution. However, empirical data about HSP90-dependent phenotypic variation and its evolutionary impact is still scarce, particularly for non-model species. Here we report how pharmacological suppression of HSP90 increases morphological variation up to 87% in the invasive ant Cardiocondyla obscurior. We show that workers treated with the HSP90 inhibitor 17-DMAG are significantly more diverse compared to untreated workers in two of four measured traits: maximal eye distance and maximal propodeal spine distance. We further find morphological differentiation between natural populations of C. obscurior in the same traits that responded to our pharmacological treatment. These findings add support for the putative impact of HSP90 on canalization, the modularity of phenotypic traits, and its potential role in morphological evolution of ants.

Honey bee (Apis mellifera) gut microbiota promotes host endogenous detoxification capability via regulation of P450 gene expression in the digestive tract.

SummaryThere is growing number of studies demonstrating a close relationship between insect gut microbiota and insecticide resistance. However, the contribution of the honey bee gut microbiota to host detoxification ability has yet to be investigated. In order to address this question, we compared the expression of cytochrome P450s (P450s) genes between gut microbiota deficient (GD) workers and conventional gut community (CV) workers and compared the mortality rates and the pesticide residue levels of GD and CV workers treated with thiacloprid or tau‐fluvalinate. Our results showed that gut microbiota promotes the expression of P450 enzymes in the midgut, and the mortality rate and pesticide residue levels of GD workers are significantly higher than those of CV workers. Further comparisons between tetracycline‐treated workers and untreated workers demonstrated that antibiotic‐induced gut dysbiosis leads to attenuated expression of P450s in the midgut. The co‐treatment of antibiotics and pesticides leads to reduced survival rate and a significantly higher amount of pesticide residues in honey bees. Taken together, our results demonstrated that honey bee gut symbiont could contribute to bee health through the modification of the host xenobiotics detoxification pathways and revealed a potential negative impact of antibiotics to honey bee detoxification ability and health.

Relationships of Obesity-Related Indices and Metabolic Syndrome with Subclinical Atherosclerosis in Middle-Aged Untreated Japanese Workers.

Aim: Obesity is a social problem due to the prevalence of the Western lifestyle. In particular, visceral fat accumulation, which is a main component of metabolic syndrome, is closely associated with the progression of atherosclerosis. This study aimed to investigate the relationships of obesity-related indices and metabolic syndrome with subclinical atherosclerosis in middle-aged untreated workers.Methods: Employees undergoing their periodic health check-up but without previous cardiovascular events or cardiovascular medications were enrolled in this study (n = 7,750). Body mass index (BMI), percent body fat, waist circumference, and visceral fat area were evaluated as obesity-related indices. Assessment of visceral fat area was performed by computed tomography (CT). Subclinical atherosclerosis was assessed by measuring arterial stiffness using cardio-ankle vascular index (CAVI) and by ultrasound examination of carotid intima-media thickness (IMT).Results: Obesity-related indices were significantly correlated with each other and were positively associated with carotid IMT but negatively associated with CAVI in multivariate regression analysis. In a logistic regression analysis including CAVI and carotid IMT simultaneously, CAVI was negatively associated, but carotid IMT was positively associated, with obesity defined by each obesity-related index. In contrast, both CAVI and carotid IMT were positively associated with the presence of metabolic syndrome based on visceral fat accumulation.Conclusions: Obesity-related indices were negatively associated with CAVI and positively associated with carotid IMT in middle-aged untreated workers, while both CAVI and carotid IMT were worsened in the presence of metabolic syndrome.

Social Buffering of Pesticides in Bumblebees: Agent-Based Modeling of the Effects of Colony Size and Neonicotinoid Exposure on Behavior Within Nests

Neonicotinoids are a globally prevalent class of pesticides that can negatively impact bees and the pollination services they provide. While there is evidence suggesting that colony size may play an important role in mitigating neonicotinoid exposure in bees, mechanisms underlying these effects are not well understood. Here, a recently developed, agent-based computational model is used to investigate how the effects of sub-lethal neonicotinoid exposure on intranest behavior of bumblebees (Bombus impatiens) are modulated by colony size. Simulations from the model, parameterized using empirical data on bumblebee workers exposed to imidacloprid (a common neonicotinoid pesticide), suggest that colony size has significant effects on behavior neonicotinoid-sensitivity within bumblebee nests. Specifically, differences are reduced between treated and untreated workers in larger colonies for several key aspects of behavior within nests. Our results suggest that changes in both number of workers and nest architecture may contribute to making larger colonies less sensitive to pesticide exposure.

Piperine as a new natural supplement with beneficial effects on the life-span and defence system of honeybees

AbstractMany factors, including pathogens, environmental change and breeding techniques, affect honeybee immunity/resistance, so substances and natural supplements that enhance it are desired. To eliminate the impact of unknown external factors, in 2016 a cage experiment was conducted under constant laboratory conditions (35 °C, 65% relative humidity). Bees in the control group were fed with sugar dissolved in water at ratio 1:1 ad libitum with no additives, while the other group was fed with sugar syrup (1:1) supplemented with piperine (3 µg/ml) ad libitum. The piperine-treated workers lived 9 days longer compared to the control group. In the piperine-consuming group, protein concentration and the activities of antioxidative enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione S-transferase (GST), were higher than in the control group. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were also higher in the piperine-treated group. Neutral and acidic proteases inhibitors, as well as neutral protease activities, were higher in the haemolymph of the piperine-treated workers than in untreated bees. Acidic protease activities in the haemolymph were higher in untreated workers only on days 18 and 32. Alkaline protease activities in the control bees were higher from day 10. From 10 days old, the total antioxidant capacity level was significantly higher in the haemolymph of piperine-treated workers. Piperine decreased DNA methylation levels significantly in the older bees. The compound could have the potential to be a natural diet supplement increasing apian resistance to stress factors.

Payroll Taxes, Firm Behavior, and Rent Sharing: Evidence from a Young Workers' Tax Cut in Sweden

This paper uses administrative data to analyze a large employer-borne payroll tax rate cut for young workers in Sweden. We find no effect on net-of-tax wages of young treated workers relative to slightly older untreated workers, and a 2–3 percentage point increase in youth employment. Firms employing many young workers receive a larger tax windfall and expand right after the reform: employment, capital, sales, and profits increase. These effects appear stronger in credit-constrained firms. Youth-intensive firms also increase the wages of all their workers collectively, young as well as old, consistent with rent sharing of the tax windfall. (JEL H25, H32, J13, J23, J31, M51)

Effects of termiticide exposure on mutual interactions between the treated and untreated workers of the Asian subterranean termiteCoptotermes gestroi

Mutual interactions, including reciprocal food sharing and grooming between chlorantraniliprole- and fipronil-treated, and untreated Asian subterranean termites, Coptotermes gestroi (Wasmann), were examined using rubidium as a tracer. Two questions were addressed in this study: (1) After insecticide treatment, does the mutual interaction between termiticide-treated termites and untreated nestmates increase? (2) Does the nutritional status of both termiticide-treated termites and untreated nestmates affect the mutual interaction? The comparative data suggested that chlorantraniliprole-treated termites were more regularly attended by untreated termites than the fipronil-treated termites. Mutual interaction between the chlorantraniliprole-treated termites and untreated termites was not affected by their nutritional status. A high level of rubidium was present in the reciprocal exchange from fipronil-treated termites to starved untreated termites, indicating that intoxication induced alimentary or anal fluids served as a food source for starved termites. The results of the present study indicated that termites exposed to chlorantraniliprole were more likely to cease feeding and then undergo starvation. Thus, the treated termites were subject to intensive reciprocal food exchange and frequent attention from untreated nestmates. In the fipronil treatment, starvation status facilitated the reciprocal food exchange rate from treated termites to starved untreated termites.

Market Externalities of Large Unemployment Insurance Extension Programs

This paper offers quasi experimental evidence of the existence of spillover effects of UI extensions using a unique program that extended unemployment benefits drastically for a subset of workers in selected regions of Austria. We use non-eligible unemployed in treated regions, and a difference-in-difference identification strategy to control for preexisting differences across treated and untreated regions. We uncover the presence of important spillover effects: in treated regions, as the search effort of treated workers plummets, the job finding probability of untreated workers increases, and their average unemployment duration and probability of long term unemployment decrease. These effects are the largest when the program intensity reaches its highest level, then decrease and disappear as the program is scaled down and finally interrupted. We use this evidence to assess the relevance of different assumptions on technology and the wage setting process in equilibrium search and matching models and discuss the policy implications of our results for the EUC extensions in the US.

Market Externalities of Large Unemployment Insurance Extension Programs

This paper offers quasi experimental evidence of the existence of spillover effects of UI extensions using a unique program that extended unemployment benefits drastically for a subset of workers in selected regions of Austria. We use non-eligible unemployed in treated regions, and a difference-in-difference identification strategy to control for preexisting differences across treated and untreated regions. We uncover the presence of important spillover effects: in treated regions, as the search effort of treated workers plummets, the job finding probability of untreated workers increases, and their average unemployment duration and probability of long term unemployment decrease. These effects are the largest when the program intensity reaches its highest level, then decrease and disappear as the program is scaled down and finally interrupted. We use this evidence to assess the relevance of different assumptions on technology and the wage setting process in equilibrium search and matching models and discuss the policy implications of our results for the EUC extensions in the US.

AGE-DEPENDENT CONDITIONED RESPONSES TO QUEEN PHEROMONE IN APIS MELLIFERA CARNICA POLLM. WORKERS FROM QUEENLESS COLONY TREATED WITH SYNTHETIC QUEEN MANDIBULAR PHEROMONE

The age-dependent electroantennogram (EAG) and conditioned proboscis extension responses to the full queen extract (QE), at a dose of 10-3 queen equivalent (Qeq), in QMP-treated (QMP+) and untreated (QMP-) workers were investigated. Our results revealed a great improvement in olfactory learning of QMP+ workers during the first 10 days of adult life. We found that learning capability developed differently in workers from QMP+ and QMP- colonies. In general, conditioned responses of QMP- workers to QE were lower than those of QMP+ workers but significant differences in conditioned response levels in QMP+ and QMP- workers were recorded on day 8 and 10 of their adult life. No significant differences were revealed between EAG responses of QMP+ and QMP- workers of the same age.

Hexamerin-based regulation of juvenile hormone-dependent gene expression underlies phenotypic plasticity in a social insect

Worker termites of the genus Reticulitermes are temporally-arrested juvenile forms that can terminally differentiate into adultsoldier- or reproductive-caste phenotypes. Soldier-caste differentiation is a developmental transition that is induced by high juvenile hormone (JH) titers. Recently, a status quo hexamerin mechanism was identified, which reduces JH efficacy and maximizes colony fitness via the maintenance of high worker-caste proportions. Our goal in these studies was to investigate more thoroughly the influences of the hexamerins on JH-dependent gene expression in termite workers. Our approach involved RNA interference (RNAi), bioassays and quantification of gene expression. We first investigated the expression of 17 morphogenesis-associated genes in response to RNAi-based hexamerin silencing. Hexamerin silencing resulted in significant downstream impacts on 15 out of the 17 genes, suggesting that these genes are members of a JH-responsive genomic network. Next, we compared gene-expression profiles in workers after RNAi-based hexamerin silencing to that of (i) untreated workers that were held away from the colony; and (ii) workers that were also held away from the colony, but with ectopic JH. Here, although there was no correlation between hexamerin silencing and colony-release effects, we observed a significant correlation between hexamerin silencing and JH-treatment effects. These findings provide further evidence supporting the hypothesis that the hexamerins modulate JH availability, thus limiting the impacts of JH on termite caste polyphenism. Results are discussed in a context relative to outstanding questions on termite developmental biology, particularly on regulatory gene networks that respond to JH-, colony- and environmental-cues.

Effects of carbon dioxide narcosis on ovary activation and gene expression in worker honeybees, Apis mellifera

In an effort to uncover genes associated with ovary activation in honey bee workers, the extent to which eight candidate genes co-varied in their expression with experimentally-induced changes in worker reproductive state was examined. Groups of caged, queenless workers narcotized with CO2 on consecutive days early in adult life showed a significantly lower level of ovary activation than did groups of untreated workers. This same experimental treatment, by contrast, is known to accelerate ovary activation and induce egg laying in virgin honey bee queens – an observation that suggests that CO2 narcosis has contrasting effects in queen versus worker ovary activation. Experimentally-induced changes to worker reproductive state were associated with changes in gene expression. Vitellogenin, an egg yolk precursor, and transferrin, an iron transporter, were two transcripts found to be significantly down-regulated as a function of the ovary-inhibiting treatment. CO2 narcosis did not effect the expression of six other genes selected as putative markers for processes that may underlie ovary activation. The show that the expression of vitellogenin and transferrin is correlated with ovary activation in workers, and may therefore be part of the gene network involved in the regulatory control of functional sterility in honeybees.

Effects of carbon dioxide narcosis on ovary activation and gene expression in worker honeybees, Apis mellifera

In an effort to uncover genes associated with ovary activation in honey bee workers, the extent to which eight candidate genes co-varied in their expression with experimentally-induced changes in worker reproductive state was examined. Groups of caged, queenless workers narcotized with CO(2) on consecutive days early in adult life showed a significantly lower level of ovary activation than did groups of untreated workers. This same experimental treatment, by contrast, is known to accelerate ovary activation and induce egg laying in virgin honey bee queens--an observation that suggests that CO(2) narcosis has contrasting effects in queen versus worker ovary activation. Experimentally-induced changes to worker reproductive state were associated with changes in gene expression. Vitellogenin, an egg yolk precursor, and transferrin, an iron transporter, were two transcripts found to be significantly down-regulated as a function of the ovary-inhibiting treatment. CO(2) narcosis did not effect the expression of six other genes selected as putative markers for processes that may underlie ovary activation. The show that the expression of vitellogenin and transferrin is correlated with ovary activation in workers, and may therefore be part of the gene network involved in the regulatory control of functional sterility in honeybees.

Supercooling Differences in the Eastern Subterranean Termite (Isoptera: Rhinotermitidae)

Supercooling points were determined for untreated field-collected and untreated laboratory-maintained Reticulitermes flavipes (Kollar) workers and soldiers. Workers treated with antibiotics or had their hindgut-protozoa removed by exposing them to oxygen under pressure to determine the effects of absence of the hindgut fauna on supercooling. Supercooling points were compared between live and freshly-killed workers to determine whether supercooling in this species might be simply due to the biochemical properties of body fluids. Laboratory-maintained workers were also subjected to desiccation, starvation, or atmospheric pressure to determine their effects on supercooling. Supercooling points were lowest for laboratory workers treated with antibiotics and those that fed on brown paper-toweling for 7 d. Untreated field-collected workers had significantly higher supercooling points than untreated laboratory-maintained workers (−6.06 ± 0.79°C vs −9.29 ± 2.38°C, P < 0.0001). Both untreated field-collected and laboratory soldiers had significantly lower supercooling points than their respective workers (−7.39 ± 2.01°C vs −6.06 ± 0.79°C, P < 0.0001; and −11.60 ± 2.53°C vs −9.29 ± 2.38°C, P< 0.0001, respectively). There was no significant association between termite body mass and supercooling points for both laboratory and field termites (P= 0.0523 and P = 0.6242) or water content of laboratory termites and supercooling points (P = 0.1425). Defaunated workers had significantly lower supercooling points (−10.34 ± 2.38°C) than normally faunated workers (−9.48 ± 1.85°C)(P= 0.0095) suggesting that the symbiotic fauna may have higher supercooling points and act as ice nucleators in the termite hindgut. Starved and desiccated workers had significantly lower supercooling points (−10.38 ± 2.70°C and −10.39 ± 2.38°C, respectively) than their corresponding control groups (−9.87 ± 2.11°C and −9.89 ± 1.94°C; P = 0.0454; P = 0.0234, respectively) and untreated workers (−9.29 ± 2.38°C; P= 0.0021; P= 0.0011) suggesting that some forms of physical stress might lower the supercooling point.

Toxicity, Repellency, and Horizontal Transmission of Fipronil in the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)

Toxicity of fipronil was evaluated against field-collected Coptoteres formosanus Shiraki. In topical application assays, fipronil was highly effective against both workers and soldiers at very low doses. Acute toxicity after 24 h was significantly greater in workers than in soldiers. The LD50s were 2.59- and 2.91-fold greater with soldiers than with workers from the two tested colonies. The LD50s of fipronil at 72 h after treatment were <2.0 ng/insect, with no significant differences regarding the tested workers/soldiers or colonies. Treated soldiers placed with untreated workers significantly increased worker mortality. However, there was no significant horizontal transmission of fipronil from treated workers to untreated soldiers. Fipronil at rates of 0.063% or less showed no repellency, whereas sand treatments of 0.125% fipronil were repellent to termite workers.

Group effects on insecticide toxicity in workers of the Formosan subterranean termite, Coptotermes formosanus Shiraki.

Coptotermes formosanus workers were treated topically with insecticide and subsequently held individually or in groups to examine possible effects on insecticide toxicity. Chlorpyrifos, cypermethrin and chlordane toxicities were 1.4-, 1.5-, and 1.3-fold greater, respectively, among workers held in groups compared with those held individually after insecticide treatment. Experiments were conducted to examine how enhanced toxicity occurred among termites held in groups after topical insecticide treatment. When workers were treated topically with chlordane and immediately placed with untreated workers, significantly greater numbers of untreated workers were killed compared with controls at all ratios examined (insecticide-treated:untreated). These data indicated that workers treated topically with insecticide were capable of somehow transferring a lethal dose of insecticide to untreated workers confined in the vial. Chlordane was recovered from untreated workers which had been confined with chlordane-treated workers; significantly higher quantities of chlordane were recovered from dead workers exposed to chlordane-treated workers compared with surviving workers exposed to chlordane-treated workers. Possible mechanisms of insecticide transfer from insecticide-treated to untreated termites are discussed.

Use of Diatomaceous Earth and Entomopathogen Combinations against the Red Imported Fire Ant (Hymenoptera: Formicidae)

Thelohania solenopsae Knell, Allen, & Hazard is a common intracellular pathogen of fire ants, Solenopsis spp., in South America and was recently discovered in the USA (Williams et al. 1998). Williams & Oi (1998) found that infected S. invicta Buren colonies produced smaller worker populations and decreased queen weights compared to uninfected colonies. This protozoan alone will not solve the S. invicta problem in the USA but could be used with other biological agents, natural products, or insecticides in a fire ant IPM program. The LC50 for Beauveria bassiana (Balsamo) Vuillemin was 4.5x higher for workers from healthy colonies than for workers from T solenopsae-infected colonies (Brinkman & Gardner 2000). Stimac et al. (1993) combined diatomaceous earth (DE) with B. bassiana in tests against S. invicta, but further studies are needed. The objective of the research reported herein was to determine the interaction of DE with either T solenopsae or B. bassiana against fire ant workers. Solenopsis invicta colonies infected with T solenopsae were originally obtained from USDA ARS CMAVE, Gainesville, FL. Healthy colonies were collected from a pasture located 8 km northwest of Griffin, GA. These colonies were tested to confirm presence or absence of T solenopsae by using procedures of Williams et al. (1998). Sixtytwo percent of workers from the T solenopsaeinfected colonies possessed octet stage spores. Thelohania solenopsae was not detected in workers from local colonies. Test arenas were 35-ml clear plastic cups containing dental plaster (1/4 volume of cup) and Fluon? (Northern Products Inc., Woonsocket, RI 02898) coated on the inside walls. The treatments tested on workers from healthy colonies were untreated controls, DE alone, B. bassiana, and B. bassiana + DE. Workers from T solenopsae-infected colonies were treated with DE. Untreated workers were kept as controls. BotaniGard? ES (Mycotech Corp., Butte, MT 59701) was pipetted in cups on the surface of the dental plaster at a rate of 2.4 x 106 B. bassiana CFUs per cm2. Cups that were treated with DE each received 0.1 g of Celite 5450 (Fisher Scientific, Pittsburgh, PA 15275). Ten ants were placed in each cup. Honey was provided as a food source, and cups were placed on wet foam. A hole in the bottom of each cup allowed the dental plaster to maintain moisture. Mortality was checked daily for 10 d. Treatments were replicated 10 times in a randomized complete block design with repeated measures. Analysis of data was with the PROC MIXED procedure (Littell et al. 1996); means were separated by LSD (ue = 0.05). At 10 d after exposure, mortality of healthy workers exposed to DE alone was 29% (Fig. 1). Arthur (2000) reported that insect mortality is directly related to DE exposure interval and Stimac et al. ( 1993) observed almost twice this level of mortality of fire ants after 22-30 d of exposure to DE. The mortality of ants from T. solenopsaeinfected colonies that were exposed to DE was significantly (F = 46.44; df = 5,9; P = 0.000 1) higher than observed with other treatments with 89'tk dead by 10 d after exposure. Although this mortality was subadditive ( Cossentine & Lewis 1984), it was relatively high. According to Cossentine & Lewis (1L984), mortality is subadditive

PID4: ECONOMIC COST OF HIV INFECTION IN UNTREATED WORKERS: AN EMPLOYER'S PERSPECTIVE

It is necessary to understand the direct and indirect costs of HIV infection in untreated workers in order to estimate the value of aggressive antiretroviral therapies from an employer's perspective. Currently the cost of HIV/AIDS from an employer's perspective is not well understood. OBJECTIVES: To estimate lifetime costs of HIV infection in untreated employees from an employer's perspective. METHODS: A simulation model was developed to predict costs of HIV infection in untreated employees from an employer's perspective over a ten-year time frame. This model utilized age, CD4+ cell counts, and plasma HIV-1 RNA level as major predictors of disease progression and expected patient survival to estimate lifetime costs. Major direct cost components were health insurance premium, life insurance premium, short-term disability benefits, long-term disability benefits, and hiring/training expenses. The indirect cost included productivity loss at work. RESULTS: For a hypothetical 35-year old HIV-positive employee with CD4+ cell counts at 380 cells/mm3 and HIV-1 RNA at 22,000 copies/ml, the model estimated that the total direct and indirect costs of HIV infection was $165,873 from the employer's perspective over a 10-year period. This included $66,659 for health insurance, $12,788 for life insurance costs, $8,580 for short-term and long-term disability benefits, $25,894 for hiring and training expenses and $51,952 due to productivity loss. Sensitivity analyses suggested that changes in employee age, CD4+ cell count, HIV-1 RNA viral load, and CD4+ cell decline rate were important parameters that significantly impact the costs of untreated HIV workers to employers. CONCLUSION: Without effective antiretroviral therapy, HIV infection could result in significant direct and indirect costs to employers. Therefore, the cost-effectiveness of treatment with advanced antiretroviral regimen should be considered for HIV infected workers.

Mechanism underlying cuticular hydrocarbon homogeneity in the antCamponotus vagus (SCOP.) (Hymenoptera: Formicidae): Role of postpharyngeal glands

The aim of the present study was to investigate the regulation and the homogeneity of the chemical signature between members ofCamponotus vagus after experimentally changing the cuticular chemical signature by topically applying hydrocarbons. Topical application of pentane (solvent) to the cuticle of isolated workers led to a significant decrease in the quantities of the cuticular hydrocarbons measured within 3 hr, followed by an increase within the following 3 hr and a period of relative stability from 9 hr to 14 days. On the other hand, after topical application to isolated workers ofn-tetracosane, a hydrocarbon existing only in trace quantity in this species, the quantity of this hydrocarbon measured over time in the epicuticular wax tended to level out at about 14 days after treatment. In contrast, topically applied (Z)-9-tricosene, an unsaturated hydrocarbon not normally synthesized by this species, decreased dramatically within a few hours and had completely disappeared within 14 days. (Z)-9-Tricosene applied to one member of a group was present in the postpharyngeal glands of the other members from 30 min to seven days of cohabitation. The highest levels were recorded in all six workers in each group after one day. GC-MS analyses showed that (Z)-9-tricosene was present in the cuticles of some untreated workers only after four and seven days of cohabitation with a treated worker. These data suggest: (1) that the deposited (Z)-9-tricosene decreased very quickly on the cuticle of the treated worker, although the total amount was spread over the cuticle and postpharyngeal gland and (2) that it was absorbed by the nontreated workers via the postpharyngeal glands during licking or grooming activities and reincorporated into the cuticle at four and seven days. When the treated worker was separated from the other ants by a wire mesh, (Z)-9-tricosene was detected neither in the cuticle nor in the postpharyngeal gland of nontreated workers.