Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cockroaches”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

Developmental constraints on the mode of reproduction in the facultatively parthenogenetic cockroach Nauphoeta cinerea.

Considerable work in evolutionary biology has focused on the question of why sex persists. Both advantages to sex and constraints limiting a return to asexual reproduction are hypothesized to maintain sex once it evolves. Developmental constraints would limit asexual reproduction from a sexual species if it were difficult for females to switch from making eggs that do not develop without fertilization to making zygotes that are capable of developing in the absence of fertilization. Nauphoeta cinerea is an ovoviviparous cockroach in which some females are capable of switching from a sexual mode of reproduction to an asexual mode when isolated from males. Yet, while facultative parthenogenesis can occur in individuals, few females make the switch. Thus, this cockroach provides an ideal system for examining the potential role of developmental constraints in maintaining sex. Here we compare the cytogenetics and embryonic development of sexual and parthenogenetic offspring in N. cinerea. We find that deviations from normal ploidy levels are associated with abnormal development. All viable N. cinerea embryos exhibit typically hemimetabolous insect embryogenesis. Although there is no variation among embryos in development within a sexually produced clutch, we see extreme variation in asexually derived clutches. These results suggest that developmental constraints limit the success of asexual reproduction in this facultatively parthenogenetic cockroach. Our data further suggest that the specific constraint occurs in the switch from a meiotic mode of reproduction requiring fertilization to diploid zygotes that develop in the absence of fertilization.

Animals↗
PubMed2001

Exposure to cockroach allergen in the home is associated with incident doctor-diagnosed asthma and recurrent wheezing.

BACKGROUND: Indoor inhaled allergens have been repeatedly demonstrated to worsen asthma in sensitized individuals, but their role in incident asthma is more controversial. OBJECTIVE: We investigated the relationship between exposure to allergens (dust mite, cat, and cockroach) measured in the home and incident doctor-diagnosed asthma and recurrent wheezing in children born to parents with asthma, allergies, or both. METHODS: From an ongoing longitudinal family and birth cohort study, we identified 222 siblings (median age, 2.87 years) of the index children. Allergen levels in the home were measured from dust samples obtained at the beginning of the study. Incident doctor-diagnosed asthma and recurrent wheezing were determined from questionnaires administered at 14 months and 22 months after the initial questionnaire. RESULTS: Thirteen (5.9%) children were reported to have incident asthma, twenty (9.0%) children had recurrent asthmatic wheezing, and 18 (8.1%) had recurrent wheezing without asthma. Compared with children living in homes with Bla g 1 or 2 levels of less than 0.05 U/g, children exposed to Bla g 1 or 2 levels of 0.05 to less than 2 U/g had a relative risk for incident asthma of 8.27 (95% confidence interval, 1.04-66.04), whereas children exposed to Bla g 1 or 2 levels of 2 U/g or greater had a relative risk for incident asthma of 35.87 (95% confidence interval, 4.49-286.62). Cockroach allergen exposure was likewise a significant predictor for recurrent asthmatic wheezing. Neither dust mite nor cat allergen levels were significantly associated with either outcome. These findings remained after control for several covariates. CONCLUSION: Exposure to cockroach allergen early in life may contribute to the development of asthma in susceptible children.

Air Pollution, Indoor↗
PubMed2002

Daycare centers and schools as sources of exposure to mites, cockroach, and endotoxin in the city of São Paulo, Brazil.

BACKGROUND: Public places, including schools, have been identified as sources of exposure to allergens derived from mites, cockroach, cat, and dog and to endotoxin. OBJECTIVES: The purposes of this study were to assess and compare exposure to allergens and endotoxin in 4 types of public child-care facilities in Brazil and to investigate whether the presence of children and the performance of cleaning procedures could have an influence on allergen and endotoxin levels. METHODS: We have analyzed dust from bedding, floors, chairs, and tables of daycare centers (DCs), preschools, kindergartens, and elementary schools (ESs). Major allergens from mites, cockroach, cat, and dog were quantitated by means of ELISA, and endotoxin content was determined by using the Limulus Amebocyte Lysate assay. RESULTS: Group 1 mite allergens were greater than 2 microg/g in 67% of DC and preschool samples and in 8.9% and 2.2% of kindergarten and ES samples, respectively. The presence of bedding in DCs and preschools accounted for increased levels of mite allergens in these settings. Levels of Bla g 1 were higher in ES floors compared with those found in DC and preschool floors. Low levels (<1 microg/g) of Fel d 1 e Can f 1 were found in most samples. Levels of endotoxin in DCs and preschools were 3 times higher than in ESs. CONCLUSIONS: DCs and schools in Brazil should be considered as important sources of exposure to dust mites and cockroach allergens and to endotoxin. Recommendations for mite allergen avoidance should include appropriate care of bedding in DCs and preschools.

Adolescent↗
PubMed1995

Molecular cloning of a major cockroach (Blattella germanica) allergen, Bla g 2. Sequence homology to the aspartic proteases.

Inhalation of allergens produced by the German cockroach (Blattella germanica) elicits IgE antibody formation and the development of asthma in genetically predisposed individuals. We compared the allergenic importance of two cockroach (CR) allergens, Bla g 1 and Bla g 2, and determined the complete amino acid sequence of the major 36-kDa allergen, Bla g2. A survey of 106 sera from CR allergic patients showed the prevalence of IgE antibodies to Bla g 1 and Bla g 2 to be 30.2% and 57.6%, respectively. Immediate skin tests on 7 selected patients gave positive reactions using 10(-3) micrograms/ml either allergen, whereas controls showed no response to 10 micrograms/ml. Natural Bla g 2 was purified and the sequence of the NH2 terminus and tryptic peptides, comprising 36% of the molecule, was determined. The cDNA for Bla g 2 was cloned from a B. germanica expression library and encoded a 24-amino acid signal peptide and a 328-amino acid mature protein, which showed the highest degree of identity to mosquito (Aedes aegypti) lysosomal aspartic protease (30.8%), with similar identity to pepsin, cathepsins D and E, renin, and chymosin. Bla g 2 mRNA and protein were detected in B. germanica, but not in Periplaneta americana, the other principal domiciliary CR species in the U.S. High concentrations of Bla g 2 were found in CR digestive organs (esophagus, gut, and proventriculus). The results show that Bla g 2 is a major species-specific allergen of B. germanica and suggest that the allergen functions as a digestive enzyme in the cockroach.

Allergens↗
PubMed1990

Nonlinear signal transmission between second- and third-order neurons of cockroach ocelli.

Transfer characteristics of the synapse made from second- to third-order neurons of cockroach ocelli were studied using simultaneous microelectrode penetrations and the application of tetrodotoxin. Potential changes were evoked in second-order neurons by either an extrinsic current or a sinusoidally modulated light. The synapse had a low-pass filter characteristic with a cutoff frequency of 25-30 Hz, which passed most presynaptic signals. The synapse operated at an exponentially rising part of the overall sigmoidal input/output curve relating pre- and postsynaptic voltages. Although the response of the second-order neuron to sinusoidal light was essentially linear, the response of the third-order neuron contained an accelerating nonlinearity: the response amplitude was a positively accelerated function of the stimulus contrast, reflecting nonlinear synaptic transmission. The response of the third-order neuron exhibited a half-wave rectification: the depolarizing response to light decrement was much larger than the hyperpolarizing response to light increment. Nonlinear synaptic transmission also enhanced the transient response to step-like intensity changes. I conclude that (a) the major function of synaptic transmission between second- and third-order neurons of cockroach ocelli is to convert linear presynaptic signals into nonlinear ones and that (b) signal transmission at the synapse between second- and third-order neurons of cockroach ocelli fundamentally differs from that at the synapse between photoreceptors and second-order neurons of visual systems so far studied, where the synapse operates in the midregion of the characteristic curve and the transmission is essentially linear.

Animals↗
PubMed2005

Mixing realities? An application of augmented reality for the treatment of cockroach phobia.

Augmented reality (AR) refers to the introduction of virtual elements in the real world. That is, the person is seeing an image composed of a visualization of the real world, and a series of virtual elements that, at that same moment, are super-imposed on the real world. The most important aspect of AR is that the virtual elements supply to the person relevant and useful information that is not contained in the real world. AR has notable potential, and has already been used in diverse fields, such as medicine, the army, coaching, engineering, design, and robotics. Until now, AR has never been used in the scope of psychological treatment. Nevertheless, AR presents various advantages. Just like in the classical systems of virtual reality, it is possible to have total control over the virtual elements that are super-imposed on the real world, and how one interacts with those elements. AR could involve additional advantages; on one side it could be less expensive since it also uses the real world (this does not need to be modeled), and it could facilitate the feeling of presence (the sensation of being there), and reality judgment (the fact of judging the experience as real) of the person since the environment he or she is in, and what he or she is seeing is, in fact the "reality." In this paper, we present the data of the first case study in which AR has been used for the treatment of a specific phobia, cockroaches phobia. It addresses a system of AR that permits exposure to virtual cockroaches super-imposed on the real world. In order to carry out the exposure, the guidelines of Ost with respect to "one-session treatment" were followed. The results are promising. The participant demonstrated notable fear and avoidance in the behavioral avoidance test before the treatment, and not only was an important decrease in the scores of fear and avoidance observed after the treatment, but also the participant was capable of approaching, interacting, and killing live cockroaches immediately following the treatment. The results are maintained in a follow-up conducted 1 month after the termination of the treatment.

Adult↗
PubMed1989

Auditory thresholds in the American cockroach (Orthoptera: Blattidae): estimates using single-unit and compound-action potential recordings.

Recent commercial suggestions that insect populations can be controlled through the use of ultrasound raises the question of whether or not certain insects have receptors that are sensitive to high-frequency sound. Single neural unit discharges and compound-action potentials were recorded from the ventral nerve cord in the American cockroach, Periplaneta americana L., to constant rise time tone pulses from 100 to 40,000 hertz (Hz). Unit responses and compound-action potentials show that the cockroach is insensitive to sound above approximately 3,000 Hz. Data relating latency of the response to intensity of the stimulus suggest that the cockroach cercal system operates on the principle of energy envelope detection. Decreases in latency likely occur primarily as a result of increases in the rate of membrane depolarization in cercal dendrites.

Action Potentials↗
PubMed1990

Influence of insecticide treatment on German cockroach (Dictyoptera: Blattellidae) movement and dispersal within apartments.

Two similar studies were done to investigate effects of insecticide treatments on German cockroach, Blattella germanica (L.), movement and dispersal within individual units in multifamily housing. In the first study, Whitmire PT-565 Pyrethrum Insect Fogger (pyrethrins), Diazinon 4E (diazinon), Protector (permethrin), and Baygon 1.5 (propoxur) did not induce any significant changes in cockroach distribution, and rates of movement within apartments decreased. In the second study, populations treated with sublethal doses of pyrethrins and resmethrin settled to their original distribution 24 h after treatment. Results from both studies indicate that thorough insecticide applications do not significantly affect German cockroach population dispersal or movement patterns within apartments.

Animals↗
PubMed1990

Insecticide toxicity, synergism and resistance in the German cockroach (Dictyoptera: Blattellidae)

The toxicity of synergism of and resistance to insecticides in four strains of German cockroach, Blattella germanica (L.), were investigated. Toxicity of nine insecticides by topical application to the susceptible strain varied greater than 2,000-fold, with deltamethrin (LD50 = 0.004 micrograms per cockroach) and malathion (LD50 = 8.4 micrograms per cockroach) being the most and least toxic, respectively. Resistance to pyrethrins (9.5-fold) in the Kenly strain was unaffected by the synergists piperonyl butoxide (PBO) or S,S,S-tributylphosphorotrithioate (DEF), suggesting that the metabolism is not involved in this case. Malathion resistance in the Rutgers strain was suppressible with PBO, implicating oxidative metabolism as a resistance mechanism. The Ectiban-R strain was resistant to all the pyrethroids tested, and cypermethrin resistance was not suppressible with PBO or DEF. These findings support results of previous studies that indicated this train has a kdr-like mechanism. Bendiocarb resistance in both the Kenly and Rutgers strains was partially suppressed by either PBO or DEF, suggesting that oxidative and hydrolytic metabolism are involved in the resistance. Trends between the effects of the synergists on the susceptible versus resistant strains are discussed.

Animals↗
PubMed1990

Toxicity of several insecticide formulations against adult German cockroaches (Dictyoptera: Blattellidae).

Toxicity of bendiocarb, chlorpyrifos, cyfluthrin, cypermethrin, fenvalerate, hydramethylnon, malathion, propetamphos, propoxur, and pyrethrins against the adult German cockroaches, Blattella germanica (L.), was investigated. At LD50, cyfluthrin was the most toxic insecticide to adult males (0.53 microgram/g), adult females (1.2 micrograms/g), and gravid females (0.85 microgram/g). Malathion was the least toxic insecticide to adult males (464.83 micrograms/g), adult females (335.83 micrograms/g), and gravid females (275.90 micrograms/g). Males and gravid females were generally more sensitive than nongravid females to the insecticides that we tested. In tests with malathion, however, males were more tolerant. The order of toxicity of the insecticide classes varied among the stages of adult German cockroaches. The order of toxicity for males and nongravid females was pyrethroids greater than pyrethrins = organophosphates (except malathion) greater than carbamates = amidinohydrazone. The order of toxicity for gravid females was pyrethroids greater than pyrethrins = organophosphates (except malathion) greater than carbamates greater than amidinohydrazone. These differences in toxicity suggest that sex differences should be considered when determining insecticide toxicity for German cockroaches.

Animals↗
PubMed1991

Influence of starvation and lighting on the movement behavior of the German cockroach (Blattodea: Blattellidae).

Computerized moving-image analysis measured the influence of starvation and lighting conditions on the locomotor activity of the German cockroach, Blattella germanica (L.). Starvation increased the distance traveled, velocity, and the proportion of time in motion of adult males and last instars but did not increase adult female movement. For females, males, and nymphs, starvation increased cockroach residence time around the source of water and harborage and decreased the distance traveled by females and nymphs around the observation arena's edge. Fluorescent light reduced the proportion of time in motion for males, but the velocity of males was greater in fluorescent light relative to infrared light. Adult males and females stopped more frequently in infrared light. Overall, males and nymphs were more mobile than females and they explored larger areas. The moving-image analysis technique is an efficient and accurate tool for observing movement of individual cockroaches and has applications in repellency, attractancy, and basic movement behavior studies.

Animals↗
PubMed1992

Measuring cypermethrin resistance in the German cockroach (Orthoptera: Blattellidae).

Cypermethrin resistance in the German cockroach, Blattella germanica (L.), was assessed by tests of surface contact and topical application. Topical application provided the most sensitive measure of resistance in a field strain. The resistance ratio (RR) measured by topical application was 122.6 for cypermethrin at LD50. As measured by surface contact, the resistance ratio at KT50 was 2.9. Differences between the walking movement of cockroaches of susceptible (VPI) and field (RHA) strains on deposits of cypermethrin influenced KT50 values. A bioassay with unrestricted movement resulted in RHA strain cockroaches accumulating a larger dose on the tarsal pads and subsequent reduction of the resistance ratio at KT50. Less walking by the VPI strain resulted in less insecticide accumulation on their tarsal pads. On a bioassay in which movement was restricted, the amount of insecticide accumulating on the tarsi was equalized, resulting in an increased resistance ratio at KT50. Differences in susceptibility were more accurately measured when the two strains were topically treated (either on the thorax or the tarsal pads) with known doses of insecticide.

Animals↗
PubMed1992

Biochemical characterization of hydrolytic and oxidative enzymes in insecticide resistant and susceptible strains of the German cockroach (Dictyoptera: Blattellidae).

We have identified resistance mechanisms in the German cockroach, Blattella germanica (L.), for propoxur and chlorpyrifos in strains of cockroaches that display multiresistance to several organophosphate and carbamate insecticides. The resistance mechanisms involve the combined effects of increased oxidative and hydrolytic metabolism and both strains are resistant to chlorpyrifos and propoxur. Experiments designed to test for similarity in metabolic enzymes suggest that, although the mechanisms involve similar processes, the enzymes responsible for insecticide detoxification are different in the two strains. Both resistant strains exhibited enhanced activity toward alpha-naphtholic esters relative to a standard susceptible strain; however, analysis of the progeny from resistant X susceptible crosses suggests that this general esterase activity is inherited differently than propoxur or chlorpyrifos resistance. Hybrids of the propoxur-resistant strain displayed the highest activity of all cockroaches tested, in contrast to hybrids of the chlorpyrifos-resistant strain, which were similar to the susceptible strain. Native gel electrophoresis of cytosolic preparations provided further evidence for differences in the pattern of hydrolytic enzymes and inheritance of resistance in the two strains. Analysis of components of the cytochrome P450-dependent monooxygenase system and activities toward model substrates indicate that the two resistance mechanisms also involve different oxidative processes. The propoxur-resistant strain displayed significantly higher levels of total cytochrome P450, but no other components were correlated with resistance. In contrast with the chlopyrifos-resistant strain, which was similar to the susceptible strain in all parameters measured, activity toward model substrates was higher in the propoxur-resistant strain than in any of the other strains and hybrids tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Influence of carbon dioxide anesthesia on chlorpyrifos toxicity in the German cockroach (Dictyoptera: Blattellidae).

Insecticide-susceptible (Orlando normal) and multi-insecticide-resistant (Village Green) adult male German cockroaches, Blattella germanica (L.), were exposed to carbon dioxide (CO2) gas in either varying durations or multiple exposures of fixed duration followed by topical treatment with acetone or chlorpyrifos (LD25) to evaluate the effect of CO2 anesthesia on chlorpyrifos toxicity. CO2 anesthesia did not increase chlorpyrifos toxicity in either strain regardless of exposure duration up to 1 h. However, multiple CO2-induced knockdowns alone caused mortality and increased chlorpyrifos toxicity. Twenty-four-hour weight loss was independent of CO2 duration exposure by strain. Village Green and Orlando cockroaches lost 5.3 and 7.6% of their weight in 24 h when treated with acetone and 10.5 and 12.8% when treated with chlorpyrifos, respectively. Conversely, 0- and 24-h weight loss increased with increasing CO2-induced knockdowns regardless of strain or topical treatment. Based on these results, CO2 used either once of limited duration (< or = 15 min) or multiple times of short duration, not to exceed four total knockdowns, does not increase chlorpyrifos toxicity in the adult male German cockroach.

Anesthesia↗
PubMed1994

Behavioral and physiological resistance to insecticides in the German cockroach (Dictyoptera: Blattellidae): an experimental reevaluation.

Although physiological resistance to pesticides has been demonstrated in German cockroaches, Blattella germanica (L.), behavioral resistance has not been shown clearly. To test for the possible development of behavioral resistance, choice-test experiments were done to determine whether adult males and females from physiologically resistant and susceptible strains differed in avoidance of three emulsifiable formulations (chlorpyrifos, cypermethrin, and chlordane). Physiological resistance was verified by estimation of LC50s. Within 6 h, each cockroach chose between an untreated and a treated harborage. In the resistant strain, both sexes avoided harborages treated with cypermethrin and survived the choice tests, but more females than males avoided harborages treated with chlorpyrifos and survived. In the susceptible strain, neither sex avoided harborages treated with cypermethrin or chlorpyrifos, and most died. The physiologically resistant strain was more resistant to chlorpyrifos and cypermethrin than was the susceptible strain, with females generally having higher LC50s. However, in choice tests with chlordane in which physiological resistance levels were similar between the strains, the strains did not differ in avoidance of treated harborages or survivorship. Avoidance of treated harborages may be facilitated by high levels of physiological resistance, but we detected no behavioral resistance traits. High levels of physiological resistance permitted cockroaches to absorb an amount of pesticide that led to detection and subsequent avoidance of treated harborages. Results of our study suggest that previous research on insects has not demonstrated the evolution of stimulus-dependent behavioral resistance in field populations exposed to pesticides.

Animals↗
PubMed2004

Laboratory evaluation of boric acid-sugar solutions as baits for management of German cockroach infestations.

Boric acid dust has a long history as an insecticide in urban pest management, and it has been shown to be an effective alternative to conventional neurotoxic insecticides. However, dust formulations require specialized equipment and are difficult to apply, whereas gel and paste formulations contain large amounts of boric acid and tend to be less efficacious than other insecticide baits. The purpose of this study was to evaluate the effectiveness of borate solutions as baits against the German cockroach. Several borate-sugar combinations were evaluated in choice and no-choice assays in the laboratory. Mortality was recorded for 15 d and expressed as lethal time90, the time taken to kill 90% of the cockroaches. Results showed that boric acid was more effective than sodium tetraborate or disodium octaborate tetrahydrate and that aqueous solutions containing mixtures of 0.5-2% boric acid and any of several inexpensive sugars, including fructose, glucose, maltose, and sucrose as a phagostimulant, at molar concentrations of 0.05-1.0, can provide rapid and effective kill of German cockroaches, Blattella germanica (L.).

Animals↗
PubMed1990

Distribution and movement patterns of German cockroaches (Dictyoptera: Blattellidae) within apartment buildings.

Trapping experiments conducted in multifamily apartments indicated movement of German cockroaches, Blattella germanica (L.), between apartments was greatest in adjacent kitchens; 65% of the emigrating cockroaches came from adjoining kitchen areas. Cockroach distribution parameters indicated that all life stages were aggregated. Aggregation was most pronounced for small nymphs, followed by adults; large nymphs were the least aggregated. Iwao's regression coefficients and resultant distributions implied movement of large nymphs was greatest, followed by adults and small nymphs.

Animals↗
PubMed1992

Sulfluramid resistance and vapor toxicity in field-collected German cockroaches (Dictyoptera: Blattellidae).

The toxicities of Raid Max Roach Bait (sulfluramid) and COMBAT Roach Control System (hydramethylnon) to susceptible and field-collected German cockroaches were examined. In all field-collected strains, a variable fraction of the population exhibited tolerance to Raid Max. In some strains, few males were killed in the first 5 d of exposure to Raid Max and some lived for up to 123 d when provided Raid Max only. Field-collected males that were given access to Raid Max for only 3 h following a 45-h starvation exhibited a 22-fold delay in mortality of 50% of the population compared with males that were continuously exposed to Raid Max. Males exposed to COMBAT for 3 h exhibited a similar pattern of mortality as males continuously exposed to this bait. Field-collected males provided COMBAT with or without rat chow exhibited identical patterns of mortality. However, males that were offered Raid Max along with rat chow exhibited significantly delayed mortality compared with males given Raid Max alone. A direct comparison of 1% hydramethylnon and sulfluramid, the active ingredients in COMBAT and Raid Max, respectively, in rat chow showed that physiological resistance to sulfluramid was involved; field-collected males consumed both baits equally on the first day, but whereas 100% of the males that were fed hydramethylnon-containing chow died within 5 d, only one of 25 males fed sulfluramid-baited rat chow died during this period, and males continued to consume large amounts of food. This suggested that, in the presence of alternate foods, the effective dose of sulfluramid was diminished, resulting in reduced mortality in males fed Raid Max. These results suggest that relatively high levels of resistance to sulfluramid are pervasive in field populations of the German cockroach. Experiments in which cockroaches were exposed to vapors of Raid Max or sulfluramid without direct contact showed that both acted as fumigants. The Raid Max bait remained lethal without direct contact for at least 170 d of continuous aeration in a fume hood. A headspace analysis revealed that sulfluramid was present in airborne collections of both technical sulfluramid and the Raid Max bait.

Animals↗