Optimisation of a screening procedure for house dust mite numbers in carpets and preliminary application to buildings

The relative performances of the mobility and heat escape methods for measuring house dust mite numbers in carpet has been evaluated. The optimum method was found to be the mobility method for 24 hours at ambient temperatures which exhibited a mite collection efficiency of approximately 30%. Measurements in three dwellings showed that the method should be applied to carpet at several locations in the living room and/or bedrooms as a general sampling procedure, or adjacent to loungeroom seating to determine the worst case scenario. Carpets using different types of fibre within the same dwelling should be assessed separately. For the limited number of dwellings investigated, wool carpets were found to exhibit higher mite numbers than nylon carpets, even when the former had been insect-resist treated. No house dust mites were found in the wool carpets of an office building which was mechanically ventilated and heated and achieved low indoor humidities in winter.     

A lack of influence of permethrin treatments of wool carpet on habitation by house dust mites

Wool carpet samples, untreated and treated with commercial levels of permethrin, were placed on a mite-inhabited carpet in a Melbourne house for 14 months. The levels of live house dust mites in the samples were found to be high at the end of this period and to exhibit no differences according to the presence of permethrin in the carpets.     

Penetration of light into carpet, and responses of the European house-dust mite (Dermatophagoides pteronyssinus) to varying light intensity and diurnal cycle

This study examined the question of what effect exposure to light might play in determining the vertical distribution of house-dust mites in carpet, and the degree to which light penetrates worn and unworn carpets of different pile conformation (loop- versus cut-pile), height and colour. The effect on population increase of a diurnal lighting cycle versus continual darkness was also investigated. It was found that the penetration of light into carpets was largely unaffected by pile colour or conformation. Pile height was an important factor, however, and for a given height within the pile, light intensity was higher in carpets subjected to a greater degree of wear. This corresponded to the reduction in effective pile height that occurs with carpet use. Whilst the differences observed were sometimes large (up to two-fold for a given height within the pile), Petri dish studies suggested no mite preference for habitation of areas of low light intensity compared to high intensity. Additionally, culturing mites under a diurnal light cycle was shown to be no more efficient than culturing in complete darkness. These results suggest that exposure to light is not an important determinant of house-dust mite behaviour, or their ability to colonise textile substrates.     

Biological Evaluation of Carpeting

Studies of microbial contamination were carried out on a carpet strip (acrilan) installed in a laboratory corridor and on two carpet strips (acrilan and wool) installed in two rooms in a pediatric hospital. A sampling procedure of randomly removing 8-mm plugs from the carpets was used for subsequent enumeration and identification of contaminating microorganisms. Microbial counts increased with time, reached a "plateau" at about 4 weeks, and appeared to be related to the amount of activity present in the carpeted area. Vacuuming of carpets showed only a slight reduction in the number of recoverable microorganisms. Qualitative studies on a strip of acrilan carpet installed in a hospital room indicated that Staphylococcus epidermidis and gram-positive nonsporeforming rods were the predominating microorganisms. Coagulase-positive S. aureus organisms were isolated during every sampling period, and gram-negative rods were also regularly isolated. Most nitrate-reducing gram-negative rods belonged to the Enterobacter and Escherichia groups. Survival studies conducted on carpet strips after hospital installation showed relatively constant levels of contamination for about 6 weeks, followed by a gradual reduction in numbers; coagulase-positive S. aureus were found for 35 days, whereas the proportions of most organisms remained relatively constant with time.     

Larval dispersal and cannibalism in a natural population of Zophobas atratus (Coleoptera: Tenebrionidae)

A natural population, of the tenebrionid beetle Zophobas atratus was studied in an attic in El Zamorano, Honduras. Larvae were living in bat guano and were, densest in the deepest part of the guano. No pupae or pharate pupae were found in the guano: they were always located a small distance away from the guano pile. Adults occurred on the guano surface and the beams and tiles of the roof. When larvae of three different ages and weights were marked and released in the guano, only the older, larger larvae were recaptured away from the guano, indicating a correlation between larval dispersal and increased weight and/or age. When 50 pharate pupae were exposed to a natural population of active larvae, only 4 (8%) survived after 5 days. This intense cannibalism of pharate pupae is consistent with the hypothesis that inhibition of pupation by crowding and the associated pre-pupal dispersal evolved, at least partly, in response to cannibalism.     

Gregarious pupation act as a defensive mechanism against cannibalism and intraguild predation

Coccinellid pupae use an array of defensive strategies against their natural enemies. This study aims to assess the efficiency of gregarious pupation as a defensive mechanism against intraguild predators and cannibals in coccinellid. The study was designed specifically (i) to determine the natural occurrence of gregarious pupation in the field for different coccinellid species, and (ii) to evaluate the adaptive value of gregarious pupation as a defensive mechanism against 2 types of predators (i.e., cannibals and intraguild predators). In the field, gregarious pupation consisted of a group of 2–5 pupae. The proportion of gregarious pupation observed varied according to species, the highest rate being observed with Harmonia axyridis Pallas (Coccinellidae; 14.17%). Gregarious pupation had no impact on the probability that intraguild predators and cannibals locate pupae. Intraguild predation occurred more often in site with gregarious pupation, while cannibalism occurred as often in site with gregarious pupation as in site with isolated pupa. However, for a specific pupa, the mortality rate was higher for isolated pupae than for pupae located in a gregarious pupation site both in the presence of intraguild predators and in the presence of cannibals. The spatial location of pupae within the group had no impact on mortality rate. Since it reduces the risk of predation, it is proposed that gregarious pupation act as a defensive mechanism for H. axyridis pupae.     

Altered surface topology and membrane functions of rat thymocytes eluted from nylon wool columns.

(1) Following incubation of thymocytes with nylon wool at 37 degrees C, the eluted cells showed an increase in the number of microvilli per cell and a concominant elongation of the microvilli (0.22 mum versus 1.15 mum. (2) Cyclic adenosine monophosphate (cylic AMP) levels were lowered by 30-50% in nylon wool-treated thymocytes. (3) Nylon wool-treated cells showed an impaired Na+-dependent amino acid transport system (2-aminoisobutyrate) whereas the Na+-independent amino acid transport system (1-aminocyclopentane-1-carboxylate) was unaffected.     

高温条件下棉铃虫化蛹率、夏滞育率和蛹重的变化

在预蛹期,高温处理能诱导棉铃虫蛹进入夏滞育。本实验着重就33～39℃的变温下滞育蛹和未滞育蛹的失重动态进行了对比研究,同时以常温（27℃）下蛹作为参照。研究发现： 在33～39℃的变温条件下,棉铃虫化蛹率显著低于其在常温下的化蛹率,且所化蛹中有63.2%的雄性和10.9%的雌性进入高温夏滞育,其中高温滞育蛹和未滞育蛹分别都轻于正常发育蛹。化蛹后第2日至第5日期间,高温滞育蛹失重量显著低于高温未滞育蛹和正常发育蛹的失重量,分别为3.62、13.30和5.49 mg;蛹期总失重量结果与化蛹后第2～5日间蛹失重量趋势一致,高温滞育蛹、未滞育蛹和正常发育蛹失重量分别为15.60、49.35和26.30 mg。蛹失重动态研究发现高温滞育蛹在夏滞育期间其失重曲线平缓,显著低于高温未滞育蛹和正常发育蛹;高温滞育蛹滞育解除后,其失重曲线与正常发育蛹的失重趋势基本一致。结果表明,棉铃虫夏滞育蛹能通过维持低的代谢水平来度过不利环境,具有一定的生态适应意义。     

Clinical studies on cell-mediated immunity in patients with malignant disease

Summary In vitro mitogenic responses of lymphocytes of patients with advanced cancer of the stomach or lung were determined and the cells involved in the depressed responses of patients characterized. Proliferative responses to phytohemagglutinin and concanavalin A of lymphocyte rich mononuclear cells of the patients were impaired, but increased after in vitro unstimulated culture for seven days. Mitogenic responses were enhanced by depletion of monocytes using a Sephadex G-10 column, and further enhanced by removal of nylon wool nonadherent cells. Nylon wool nonadherent cells of the patients suppressed the mitogenic responses of autologous and allogeneic lymphocytes, but lost the suppressive activity during seven days' in vitro culture. Nonadherent cells of normal donors did not inhibit mitogenic responses. The results suggest that peripheral blood mononuclear cells of cancer patients may contain at least two populations of suppressor cells for mitogenic responses, monocytes and nylon wool nonadherent cells, which could be one of the causes of impaired mitogenic responses in these cancer patients.     

Interactions of environmental factors influencing pupal coloration in swallowtail butterfly Papilio xuthus

The swallowtail butterfly Papilio xuthus Linné [Lepidoptera: Papilionidae] exhibits pupal protective color polyphenism. Interactions of various environmental factors on pupal coloration were analyzed in non-diapausing individuals. Under sufficient light (200lux), most pupating larvae became green pupae when the surface of the pupation site was smooth, while they became brown when the surface was rough. Tactile signals are the positive environmental factors causing induction of the brown pupal coloration. In dark boxes, the induction of the brown pupal coloration was easily induced even on a smooth surface, suggesting that light suppresses induction of brown coloration. Different colors of pupation sites did not affect pupal coloration under sufficient light. Environmental factors received during a critical period both before girdling and after girdling affected pupal coloration. When tactile signals received from rough surfaces reach threshold levels during pupation, brown pupal coloration is determined. Larvae reared under a daily periodicity of natural light formed a girdle at midnight, subsequently, the prepupae received strong daylight the following day. Under natural light most larvae produced brown pupae on rough surfaces and green pupae on smooth surfaces.     

Coral frameworks revisited–reefs and coral carpets in the northern Red Sea

 Coral communities were investigated in the northern Red Sea, in the Gulfs of Suez and Aqaba, for their framework building potential. Five types of coral frameworks were differentiated: Acropora reef framework, Porites reef framework, Porites carpet, faviid carpet, and Stylophora carpet. Two non-framework community types were found: the Stylophora-Acropora community, and soft coral communities. Reef frameworks show a clear ecological zonation along depth and hydrodynamic exposure gradients, with clear indicator communities for each zone. By definition, coral carpets build a framework but lack distinct zonation patterns since they grow only in areas without pronounced gradients. In the northern Red Sea they show a gradual change with depth from Porites to faviid dominance. A Stylophora carpet is restricted to shallow water in the northern Gulf of Suez. Although growth rates of carpets may be somewhat less than those of reefs, the carbonate accumulation is considered to be higher in carpet areas due to their significantly higher areal extension. In addition, reefs and carpets have different sediment retention characteristics – the carpet retains, the reef exports. The in situ fossilization potential of coral carpets is expected to be higher than that of reef frameworks. Accepted: 25 May 1999     

Pupal diapause of Helicoverpa armigera (Lepidoptera: Noctuidae): sensitive stage for thermal induction in the Okayama (western Japan) population

Helicoverpa armigera (Hübner) exhibits a facultative pupal diapause, which depends on temperature and photoperiod. Pupal diapause is induced at 20 degrees C by short photoperiods and inhibited by long photoperiods during the larval stage. However, in some pupae (35% of males and 57% of females) of a non-selected field population from Okayama Prefecture (34.6 degrees N), diapause is not induced by short photoperiods. In the present experiment, the importance of temperature for diapause induction was studied in the non-diapausing strain, which was selected from such individuals reared at 20 degrees C under a short photoperiod of 10L:14D. Furthermore, the sensitive stage for thermal determination of pupal diapause was determined by transferring larvae of various instars and pupae between 20 degrees C and 15 degrees C. Diapause was induced by 15 degrees C without respect to photoperiod. When larvae or pupae reared from eggs at 20 degrees C under a short or a long photoperiod were transferred to 15 degrees C in the periods of the middle fifth instar to the first three days after pupation, the diapause induction rate was significantly reduced in both males and females, especially in females. In contrast, when larvae or pupae reared at 15 degrees C were transferred to 20 degrees C in the same periods, diapause was induced in males, but not in females. However, the diapause induction rate of pupae transferred to 20 degrees C on the fourth day after pupation was significantly increased in females. The results show that temperature is the major diapause cue in the photoperiod-insensitive strain and the periods of middle fifth larval instar to early pupal stage are the thermal sensitive stages for pupal diapause induction with some different responses to temperatures between males and females in H. armigera.     

Hormonal control of the orange coloration of diapause pupae in the swallowtail butterfly, Papilio xuthus L. (Lepidoptera: Papilionidae)

Diapause pupae of Papilio xuthus show color polymorphism, represented by diapause-green, orange, and brownish-orange types that are each associated with specific pupation sites. We investigated the role of the site of pupation on the induction of the development of orange types (or brownish-orange types), and the endocrine mechanism underlying the control of color polymorphism in short-day pupae. All short-day larvae of the wandering stage developed into orange or brownish-orange type pupae when they were placed in rough-surfaced containers after gut-purge. Utilizing a pharate pupal ligation between the thorax and abdomen, the endocrine mechanism underlying the control of color polymorphism was shown to involve a head-thorax factor (Orange-Pupa-Inducing Factor: OPIF) that induced orange types in short-day pupae. OPIF was bioassayed using the ligated abdomens of short-day pharate pupae. OPIF was extractable with 2% NaCl solution from 5th-instar larval ganglia complexes following the mesothoracic complex (TG(2,3)-AG(1-7)), but it could not be extracted with either acetone or 80% ethanol solution. OPIF may not exist in the brains of day-0 pupae or in brain-subesophageal ganglion and prothoracic ganglion complexes of 5th-instar larvae. The short-day pharate pupae responded to OPIF in a dose-dependent manner.     

Adhesion,spreading, and proliferation of cells on protein carpets: Effects of stability of a carpet

Summary In the present report we have investigated the role that the physical properties of substrata play in modulating the effects which components of extracellular matrix (ECM) exert on adhesion, spreading, and growth of retinal pigmented epithelial cells. By simple modifications of conditions for protein adsorption on glass we obtained a set of substrata all coated with proteins of ECM (protein carpets) but with different physical properties. Using these protein carpets we have shown that their stability (desorption rate) in tissue culture conditions varies according to the technique with which they were prepared. Both semiremovable and immobilized carpets are stable, whereas removable protein carpets desorb readily. Therefore, the protein concentration or composition or both may change with time in tissue culture depending on the technique used to prepare the carpet. In addition, efficacy of cell attachment to given protein may vary depending on whether a technique used to prepare the protein carpet involves denaturation of the protein. Adherent cells quickly remove (clear) weakly adsorbed protein carpets and it seems that the carpet removal is a mechanical process. During the carpet removal cells are rounded, which indicates that a spread cell phenotype normally associated with stress fibers and focal contacts occurs when the substratum is rigid enough to sustain cell traction. In addition, substrata lacking the rigidity to support the spread phenotype do not support cell proliferation either.     

Relationship between mycobiota in wall-to-wall carpet dust and age of carpet

The objective of this study was to evaluate thefungal concentrations within carpets of the same typeand manufacture during their first 2 years of life.The carpets tested came from several different branchoffices of a bank.A total of 60 dust samples from 20 carpets (3samples per carpet) was analysed. The age of thecarpets varied from 50 to 666 days. Analysis of therelationship between fungal concentration and time wasmade by the Pearson test.Fungal concentrations were very different withina same carpet. Moreover, species distribution was alsoheterogeneous; thus the fungi in 1 m² carpet didnot reflect mycobiota of the whole carpet. Very localfungal contaminations (>10 CFU/mg/dust) were builtup in a relatively short time (138 days). Thehighest concentrations (maximum: 200 CFU/mg dust) weremainly due to species of coelomycetes (mitosporicfungi forming conidia in closed bodies) and to variousyeasts. Comparisons of the 20 carpets sampled did notshow significant differences; the fungal level did notincrease with time (P > 0.05). A decrease waseven noticed. The age of carpets had no significanteffect either on the number of CFU/mg dust of the mainfungal taxa (P > 0.10).It was concluded that these carpets, which wereregularly cleaned, in this particular environment, donot favour important fungal growth. Moreover, sincethe species responsible for the highest contaminationobserved produce conidia or cells not easilytransported through the air, their role in respiratoryallergy would be relatively limited.     

Fine-scale abundance and distribution of wild silk moth pupae

Although several factors influence herbivore insect distributions at any particular scale, the most important determinants are likely to differ between species with different life histories. Identifying what these factors are and how they relate to life history forms an important component of understanding the population dynamics of species, and the habitat requirements necessary for their conservation. The pupal stage of two wild silk moth species, Gonometa postica Walker and G. rufobrunnea Aurivillius (Lepidoptera: Lasiocampidae), is the target of harvesting practices that are totally dependent on the availability of pupae from natural populations. Consequently, and partly due to poor knowledge of the species' biology, there is substantial interest in the distribution of pupae among and within trees for both these species. It was investigated whether between- and within-tree pupal distributions in these two species are non-random, and if so, whether there are relationships between pupation site use and tree characteristics such as tree size, available pupation space and branch position. Between-tree patterns in pupal abundance were random in terms of absolute spatial position, but markedly non-random with respect to tree characteristics. The apparent G. postica pupae were aggregated on large larval host plants, whereas the cryptic G. rufobrunnea pupae were aggregated on non-host plants. These patterns reflect the life history differences of the two species. In contrast, at the within-tree scale, branch position, aspect and tree shape influenced pupation site choice similarly for both species. These patterns might be related to microclimate. Documenting between-tree and within-tree patterns in Gonometa pupal distributions is the first step towards explaining pupation site selection, as well as identifying possible evolutionarily selective factors in the species, and generating testable hypotheses from these.     

Comparative efficacy on dogs of a single topical treatment with fipronil/(S)-methoprene or weekly physiological hygiene shampoos against Ctenocephalides felis in a simulated flea-infested environment

Flea infestations of pets continue to persist due to the lack of knowledge of flea biology and ecology. It is not unusual that pet owners believe regular hygiene, such as shampooing their dogs can replace regular insecticidal treatment. The objective of this study was to compare in a flea simulated environment, modelling exposure similar to that found in a home, that the use of regular physiological shampoo does not control fleas adequately when compared to a long acting topical formulation. Three groups of six dogs were formed: one untreated control group, one group treated monthly with the topical formulation of fipronil/(S)-methoprene, and a third group treated weekly with a hygiene shampoo. All dogs were infested with adult unfed Ctenocephalides felis fleas (200±5) on Days -28 and -21. Each animal's sleeping box was fitted with a plastic cup mounted to the inside roof of the box. The sleeping bench of each animal was covered with a carpet to accommodate flea development. The dogs were maintained in their kennels throughout the study. In order to maintain the environmental flea challenge, C. felis pupae (100±5) were placed in the plastic cup in each animal's sleeping box on Days -14, -7, 0, 7, 14, 21, 28, 35 and 42. The dogs were combed and fleas counted weekly on Days -1, 3, 10, 17, 24, 31, 38, 45, and 51. The fleas were placed immediately back on the dogs. On Day 60, fleas were counted and removed. Flea infestations in the untreated control group at each count averaged between 46.2 and 74.2 fleas throughout the study. The average number of fleas infesting dogs was significantly different (p<0.05) between the untreated and the two treatment groups and between the two treatment groups at all counts throughout the two months study (Days 3, 10, 17, 24, 31, 38, 45, 51 and 60). The efficacy was never below 99.1% in the fipronil/(S)-methoprene group, and efficacy in the shampoo group was never above 79.2%. Weekly shampooing in treatment group 3 was intentionally delayed after Day 42, to evaluate wether missing a weekly bath would affect the flea population. The Day 48 data indicate that forgetting or delaying a single weekly shampooing resulted in a clear increase in flea numbers and a significant decrease in efficacy from 68.2% to 34.8%. The fipronil(S)/methoprene treatment allowed a continuous control as demonstrated by the high efficacy against fleas, and also the number of flea-free dogs on seven of the nine weekly assessments, in spite of what was essentially a continuous flea challenge model.     

南美斑潜蝇蛹期的生物学特性

南美斑潜蝇Liriomyzahuidobrensis在 1 5 ,2 0 ,2 5 ,30 ,35℃时 ,其蛹的历期分别为 34 5 ,1 5 8,1 0 1 ,7 2d ,而在 35℃时则不能正常羽化。土壤相对含水量为 30 %～ 90 %均比较适合南美斑潜蝇蛹的发育 ,就死亡率而言 ,它们之间没有显著差异。浸水处理表明 ,南美斑潜蝇的预蛹及蛹的初期和末期对浸水比较敏感 ,死亡率均达到 90 %以上 ,而处于中间期的蛹对浸水相对不敏感。田间调查和室内饲养均发现 ,南美斑潜蝇在 1 2时以前的化蛹个数占 1d总化蛹个数的 90 %以上 ,而 1 4时以前的羽化数占 1d总羽化数的 99%以上。南美斑潜蝇化蛹的场所在不同时期不同的蔬菜上有所不同 ,越冬时主要是以蛹在越冬寄主田的土壤中越冬 ,在生长季节 ,除了在菜豆的叶片反面化蛹外 ,其它蔬菜上则是在土壤和下部叶鞘上化蛹。     

Phase responses in the circannual rhythm of the varied carpet beetle, Anthrenus verbasci, under naturally changing day length

In the varied carpet beetle, Anthrenus verbasci, we examined the effects on the circannual pupation rhythm of a short-day or long-day pulse under naturally changing day length at a constant 20 degrees C. A short-day pulse for 4 weeks caused a prominent phase delay or advance under constant long days, but had little or no effect on the phase under naturally changing day length between 4 August and 24 November. A long-day pulse for 4 weeks given under naturally changing day length caused a phase shift in the first pupation group, as under constant short days. A long-day pulse given on 4 August, 1 September, or 29 September caused a phase delay, and a pulse given on 27 October or 24 November caused a phase advance. Pupation was least synchronous just before the transition from delaying to advancing. However, the magnitude of phase delays was much smaller under natural day length than under short days. In the second pupation group, larvae pupated at the same time as in the control experiment without a long-day pulse, and this result can be attributed to entrainment to the geophysical year by long days in spring and summer.     

葱蝇非滞育、 冬滞育和夏滞育蛹发育和形态特征比较

昆虫非滞育、 冬滞育和夏滞育蛹具有不同的生理和发育过程。本研究以葱蝇Delia antiqua作为模式种, 以黑腹果蝇Drosophila melanogaster蛹的发育形态特征和命名为参照, 用解剖、 拍照、 长度测量和图像处理等方法系统地比较研究了非滞育、 冬滞育和夏滞育蛹的发育历期和形态变化, 重点在头外翻和滞育相关发育和形态特征, 目的在于弄清非滞育、 冬滞育和夏滞育蛹发育和形态特征差异, 为滞育发育阶段的识别、 滞育分子机理研究奠定形态学基础。冬滞育蛹的滞育前期、 滞育期和滞育后期分别为4, 85和27 d, 夏滞育蛹的滞育前期、 滞育期和滞育后期分别为2, 8和22 d。从化蛹至头外翻完成为滞育前期, 头外翻完成约10 h内复眼中央游离脂肪体可见。头外翻的完成是滞育发生的前提, 非滞育、 夏滞育和冬滞育蛹头外翻发生在化蛹后的48, 36和83 h, 在头外翻过程中发育形态没有差异。头外翻的过程为： 首先, 头囊和胸部附肢从胸腔外翻, 头部形态出现; 然后, 腹部肌肉继续收缩, 将血淋巴和脂肪体推进头部及胸部附肢。葱蝇蛹在完成蛹期有效积温约15%时进入冬滞育或夏滞育。在滞育期, 蛹的形态一直停留在复眼中央游离脂肪体可见这一形态时期, 且冬滞育和夏滞育的蛹在形态上没有区别。在体长、 体宽和体重上, 冬滞育蛹最大, 夏滞育蛹次之, 非滞育蛹最小。在滞育后期, 在黄色体出现期间, 非滞育蛹的马氏管清楚可见, 呈绿色, 而滞育蛹的马氏管几乎不可见。本研究为认知昆虫滞育生理、 从发育历期和形态上推断滞育发育进程提供了依据。