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Sample records for two-spotted spider mites

  1. Alternative phenotypes of male mating behaviour in the two-spotted spider mite

    NARCIS (Netherlands)

    Sato, Y.; Sabelis, M.W.; Egas, M.; Faraji, F.

    2013-01-01

    Severe intraspecific competition for mates selects for aggressive individuals but may also lead to the evolution of alternative phenotypes that do not act aggressively, yet manage to acquire matings. The two-spotted spider mite, Tetranychus urticae, shows male mate-guarding behaviour and male-male

  2. Alternative male mating behaviour in the two-spotted spider mite: dependence on age and density

    NARCIS (Netherlands)

    Sato, Y.; Sabelis, M.W.; Egas, M.

    2014-01-01

    Highlights • We investigated alternative male mating behaviour in the two-spotted spider mite. • We found no differences between genetic lines of fighting and sneaking behaviour. • The proportion of sneaker males changed with male density and with male age. • In competition with old males, young

  3. Protocols for the delivery of small molecules to the two-spotted spider mite, Tetranychus urticae.

    Directory of Open Access Journals (Sweden)

    Takeshi Suzuki

    Full Text Available The two-spotted spider mite, Tetranychus urticae, is a chelicerate herbivore with an extremely wide host range and an extraordinary ability to develop pesticide resistance. Due to its responsiveness to natural and synthetic xenobiotics, the spider mite is becoming a prime pest herbivore model for studies of the evolution of host range, plant-herbivore interactions and mechanisms of xenobiotic resistance. The spider mite genome has been sequenced and its transcriptional responses to developmental and various biotic and abiotic cues have been documented. However, to identify biological and evolutionary roles of T. urticae genes and proteins, it is necessary to develop methods for the efficient manipulation of mite gene function or protein activity. Here, we describe protocols developed for the delivery of small molecules into spider mites. Starting with mite maintenance and the preparation of the experimental mite populations of developmentally synchronized larvae and adults, we describe 3 methods for delivery of small molecules including artificial diet, leaf coating, and soaking. The presented results define critical steps in these methods and demonstrate that they can successfully deliver tracer dyes into mites. Described protocols provide guidelines for high-throughput setups for delivery of experimental compounds that could be used in reverse genetics platforms to modulate gene expression or protein activity, or for screens focused on discovery of new molecules for mite control. In addition, described protocols could be adapted for other Tetranychidae and related species of economic importance such as Varroa, dust and poultry mites.

  4. Genetic diversity within and among two-spotted spider mite resistant and susceptible common bean genotypes

    Directory of Open Access Journals (Sweden)

    Zeinab YOUSEFI

    2017-12-01

    Full Text Available Two-spotted spider mite (Tetranychus urticae C. L. Koch, 1836, is one of the most destructive herbivores of common bean. Very little is known about the diversity among resistant sources in this crop. The present study was conducted to characterize 22 resistant and susceptible common bean genotypes by 8 Simple Sequence Repeats (SSRs and 8 Random Amplified Polymorphic DNA (RAPD markers. These SSR and RAPD primers produced 100 % and 81.8 % polymorphic bands. Based on RAPD fingerprints and SSR profiles, pairwise genetic similarity ranged from 0.0 to 0.857 and from 0.125 to 1, respectively. The resistant and susceptible common bean accessions were grouped together in the dendrograms generated from RAPD and SSR clustering analyses. The results indicate that RAPD and SSR analysis could be successfully used for the estimation of genetic diversity among genotypes. SSR markers could group genotypes according to their resistibility and susceptibility to the spotted spider mite but RAPD could not. Therefore, the SSR markers can facilitate the development of resistant common bean cultivars through breeding programs against T. urticae.

  5. Alternative phenotypes of male mating behaviour in the two-spotted spider mite.

    Science.gov (United States)

    Sato, Yukie; Sabelis, Maurice W; Egas, Martijn; Faraji, Farid

    2013-09-01

    Severe intraspecific competition for mates selects for aggressive individuals but may also lead to the evolution of alternative phenotypes that do not act aggressively, yet manage to acquire matings. The two-spotted spider mite, Tetranychus urticae, shows male mate-guarding behaviour and male-male combat for available females. This may provide opportunity for weaker males to avoid fighting by adopting alternative mating behaviour such as sneaker or satellite tactics as observed in other animals. We investigated male precopulatory behaviour in the two-spotted spider mite by means of video-techniques and found three types of male mating behaviour: territorial, sneaker and opportunistic. Territorial and sneaker males associate with female teleiochrysales and spend much time guarding them. Territorial males are easily disturbed by rival males and engage themselves in fights with them. However, sneaker males are not at all disturbed by rival males, never engage in fights and, strikingly, never face attack by territorial males. Opportunistic males wander around in search of females that are in the teleiochrysalis stage but very close to or at emergence. To quickly classify any given mate-guarding male as territorial or sneaker we developed a method based on the instantaneous response of males to disturbance by a live male mounted on top of a brush. We tested this method against the response of the same males to natural disturbance by two or three other males. Because this method proved to be successful, we used it to collect territorial and sneaker males, and subjected them to morphological analysis to assess whether the various behavioural phenotypes are associated with different morphological characters. However, we found no statistical differences between territorial and sneaker males, concerning the length of the first legs, the stylets, the pedipalps or the body.

  6. Evaluation of selected acaricides against two-spotted spider mite (Acari: Tetranychidae) on greenhouse cotton using multispectral data

    Science.gov (United States)

    Two-spotted spider mite (TSSM), Tetranychus urticae (Koch), is an early season pest of cotton in the mid-southern United States and causes reduction in yield, fiber quality and impaired seed germination. Objectives of this study were to investigate the efficacy of abamectin and spiromesifen with two...

  7. Behavioural responses of two-spotted spider mites induced by predator-borne and prey-borne cues.

    Science.gov (United States)

    Gyuris, Enikő; Szép, Erna; Kontschán, Jenő; Hettyey, Attila; Tóth, Zoltán

    2017-11-01

    Applying predatory mites as biological control agents is a well established method against spider mites which are major pests worldwide. Although antipredator responses can influence the outcome of predator-prey interactions, we have limited information about what cues spider mites use to adjust their behavioural antipredator responses. We experimentally exposed two-spotted spider mites (Tetranychus urticae) to different predator-borne cues (using a specialist predator, Phytoseiulus persimilis, or a generalist predator, Amblyseius swirskii), conspecific prey-borne cues, or both, and measured locomotion and egg-laying activity. The reactions to predator species compared to each other manifested in reversed tendencies: spider mites increased their locomotion activity in the presence of P. persimilis, whereas they decreased it when exposed to A. swirskii. The strongest response was triggered by the presence of a killed conspecific: focal spider mites decreased their locomotion activity compared to the control group. Oviposition activity was not affected by either treatment. Our results point out that spider mites may change their behaviour in response to predators, and also to the presence of killed conspecifics, but these effects were not enhanced when both types of cues were present. The effect of social contacts among prey conspecifics on predator-induced behavioural defences is discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Vitamin A deficiency modifies response of predatory mite Amblyseius potentillae to volatile kairomone of two-spotted spider mite, Tetranychus urticae.

    NARCIS (Netherlands)

    Dicke, M.; Sabelis, M.W.; Groeneveld, A.

    1986-01-01

    volatile kairomone of the two-spotted spider mite,Tetranychus urticae, elicits a searching response of the phytoseiid predatorAmblyseius potentillae, only when the predator is reared on a carotenoid-free diet. However, after addition of crystalline betta-carotene or vitamin A acetate to the

  9. Interactions between natural enemies: Effect of a predatory mite on transmission of the fungus Neozygites floridana in two-spotted spider mite populations.

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    Trandem, Nina; Berdinesen, Ronny; Pell, Judith K; Klingen, Ingeborg

    2016-02-01

    Introducing the predatory mite Phytoseiulus persimilis into two-spotted spider mite, Tetranychus urticae, populations significantly increased the proportion of T. urticae infected with the spider mite pathogen Neozygites floridana in one of two experiments. By the final sampling occasion, the number of T. urticae in the treatment with both the predator and the pathogen had declined to zero in both experiments, while in the fungus-only treatment T. urticae populations still persisted (20-40 T. urticae/subsample). Releasing P. persimilis into crops in which N. floridana is naturally present has the potential to improve spider mite control more than through predation alone. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Deciphering the Metabolic Changes Associated with Diapause Syndrome and Cold Acclimation in the Two-Spotted Spider Mite Tetranychus urticae

    Science.gov (United States)

    Khodayari, Samira; Moharramipour, Saeid; Larvor, Vanessa; Hidalgo, Kévin; Renault, David

    2013-01-01

    Diapause is a common feature in several arthropod species that are subject to unfavorable growing seasons. The range of environmental cues that trigger the onset and termination of diapause, in addition to associated hormonal, biochemical, and molecular changes, have been studied extensively in recent years; however, such information is only available for a few insect species. Diapause and cold hardening usually occur together in overwintering arthropods, and can be characterized by recording changes to the wealth of molecules present in the tissue, hemolymph, or whole body of organisms. Recent technological advances, such as high throughput screening and quantification of metabolites via chromatographic analyses, are able to identify such molecules. In the present work, we examined the survival ability of diapausing and non-diapausing females of the two-spotted spider mite, Tetranychus urticae, in the presence (0 or 5°C) or absence of cold acclimation. Furthermore, we examined the metabolic fingerprints of these specimens via gas chromatography-mass spectrophotometry (GC-MS). Partial Least Square Discriminant Analysis (PLS-DA) of metabolites revealed that major metabolic variations were related to diapause, indicating in a clear cut-off between diapausing and non-diapausing females, regardless of acclimation state. Signs of metabolic depression were evident in diapausing females, with most amino acids and TCA cycle intermediates being significantly reduced. Out of the 40 accurately quantified metabolites, seven metabolites remained elevated or were accumulated in diapausing mites, i.e. cadaverine, gluconolactone, glucose, inositol, maltose, mannitol and sorbitol. The capacity to accumulate winter polyols during cold-acclimation was restricted to diapausing females. We conclude that the induction of increased cold hardiness in this species is associated with the diapause syndrome, rather than being a direct effect of low temperature. Our results provide novel

  11. Evaluation of airborne methyl salicylate for improved conservation biological control of two-spotted spider mites and hop aphid in Oregon hop yards

    Science.gov (United States)

    The use of synthetic herbivore-induced plant volatiles (HIPV) to attract natural enemies has received interest as a tool to enhance conservation biological control (CBC). Methyl salicylate (MeSA) is a HIPV that is attractive to several key predators of two-spotted spider mite, Tetranychus urticae K...

  12. Múltiple natural enemies do not improve two spotted spider mite and flower western thrips control in strawberry tunnels

    Directory of Open Access Journals (Sweden)

    Gemma Albendín

    2015-03-01

    Full Text Available Biological control techniques are commonly used in many horticultural crops in Spain, however the application of these techniques to Spanish strawberries are relatively recent. In this study the effectiveness of augmentative biological control techniques to control the two main strawberry (Fragaria xananassa Duchesne pest: the two-spotted spider mite (TSSM, Tetranychus urticae Koch (Acari: Tetranychidae, and the western flower thrips (WFT, Frankliniella occidentalis (Pergande (Thysanoptera: Thripidae, through releases of the predatory mites Phytoseiulus persimilis Athias-Henriot, Neoseiulus californicus (McGregor, Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae, and Orius laevigatus (Fieber (Heteroptera: Anthocoridae were tested. Two-year results on the performance of treatments using combinations of these biocontrol agents are presented. In both years, all treatments resulted in the reduction of TSSM numbers; but no treatment was better than the release of P. persimilis alone (P < 0.05. TSSM suppression varied among crop phases being greater early in the season. None of the treatments reduced significantly WFT numbers (P < 0.05, and the established economic injury level (EIL was surpassed from March to late April in both years. However, EIL was surpassed less times when treatment included O. laevigatus (2009: 20.7%; 2010: 22.7% of samples. No effect of A. swirskii was observed when this mite was released. Results corroborate that biological control techniques for TSSM and WFT are feasible for high-plastic tunnel strawberries. Under the conditions in our study no additive effects were observed, and there was not advantage in the release of multiple natural enemies.

  13. The predatory mite Neoseiulus womersleyi (Acari: Phytoseiidae) follows extracts of trails left by the two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae).

    Science.gov (United States)

    Shinmen, Tsubasa; Yano, Shuichi; Osakabe, Mh

    2010-10-01

    As it walks, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) spins a trail of silk threads, that is followed by the predatory mite, Neoseiulus womersleyi Schicha (Acari: Phytoseiidae). Starved adult female N. womersleyi followed T. urticae trails laid down by five T. urticae females but did not follow a trail of one T. urticae female, suggesting that the amount of spun threads and their chemical components should correlate positively with the number of T. urticae individuals. To examine whether chemical components of T. urticae trails are responsible for the predatory mite's trail following, we collected separate T. urticae threads from the exuviae and eggs, and then washed the threads with methanol to separate chemical components from physical attributes of the threads. Female N. womersleyi did not follow T. urticae trails that had been washed with methanol but contained physical residues, but they did follow the direction to which the methanol extracts of the T. urticae trails was applied. These results suggest that the predatory mite follows chemical, not physical, attributes of T. urticae trails.

  14. Evaluation of airborne methyl salicylate for improved conservation biological control of two-spotted spider mite and hop aphid in Oregon hop yards.

    Science.gov (United States)

    Woods, J L; James, D G; Lee, J C; Gent, D H

    2011-12-01

    The use of synthetic herbivore-induced plant volatiles (HIPV) to attract natural enemies has received interest as a tool to enhance conservation biological control (CBC). Methyl salicylate (MeSA) is a HIPV that is attractive to several key predators of two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), and hop aphid, Phorodon humuli (Schrank) (Homoptera: Aphididae). A 2-year study was conducted to evaluate the recommended commercial use of MeSA in hop yards in Oregon. Slow-release MeSA dispensers were stapled to supporting poles in 0.5 ha plots and these plots were compared to a paired non-treated plot on each of three farms in 2008 and 2009. Across both years, there was a trend for reduced (range 40-91%) mean seasonal numbers of T. urticae in five of the six MeSA-baited plots. Stethorus spp., key spider mite predators, tended to be more numerous in MeSA-baited plots compared to control plots on a given farm. Mean seasonal densities of hop aphid and other natural enemies (e.g., Orius spp. and Anystis spp.) were similar between MeSA-treated and control plots. Variability among farms in suppression of two-spotted spider mites and attraction of Stethorus spp. suggests that the use of MeSA to enhance CBC of spider mites in commercial hop yards may be influenced by site-specific factors related to the agroecology of individual farms or seasonal effects that require further investigation. The current study also suggests that CBC of hop aphid with MeSA in this environment may be unsatisfactory.

  15. Can Plant Defence Mechanisms Provide New Approaches for the Sustainable Control of the Two-Spotted Spider Mite Tetranychus urticae?

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    Blas Agut

    2018-02-01

    Full Text Available Tetranychus urticae (T. urticae Koch is a cosmopolitan, polyphagous mite which causes economic losses in both agricultural and ornamental plants. Some traits of T. urticae hamper its management, including a short life cycle, arrhenotokous parthenogenesis, its haplodiploid sex determination system, and its extraordinary ability to adapt to different hosts and environmental conditions. Currently, the use of chemical and biological control are the major control methods used against this mite. In recent years, some studies have focused on plant defence mechanisms against herbivores. Various families of plant compounds (such as flavonoids, glucosinolates, or acyl sugars have been shown to behave as acaricides. Plants can be induced upon appropriate stimuli to increase their resistance against spider mites. This knowledge, together with the understanding of mechanisms by which T. urticae detoxifies and adapts to pesticides, may complement the control of this pest. Herein, we describe plant volatile compounds (VOCs with repellent activity, and new findings about defence priming against spider mites, which interfere with the T. urticae performance. The use of VOCs and defence priming can be integrated into current management practices and reduce the damage caused by T. urticae in the field by implementing new, more sustainable crop management tools.

  16. Leaf-morphology-assisted selection for resistance to two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in carnations (Dianthus caryophyllus L).

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    Seki, Kousuke

    2016-10-01

    The development of a cultivar resistant to the two-spotted spider mite has provided both ecological and economic benefits to the production of cut flowers. This study aimed to clarify the mechanism of resistance to mites using an inbred population of carnations. In the resistant and susceptible plants selected from an inbred population, a difference was recognised in the thickness of the abaxial palisade tissue by microscopic examination of the damaged leaf. Therefore, it was assumed that mites displayed feeding preferences within the internal leaf structure of the carnation leaf. The suitability of the host plant for mites was investigated using several cultivars selected using an index of the thickness from the abaxial leaf surface to the spongy tissue. The results suggested that the cultivar associated with a thicker abaxial tissue lowered the intrinsic rate of natural increase of the mites. The cultivars with a thicker abaxial tissue of over 120 µm showed slight damage in the field test. The ability of mites to feed on the spongy tissue during an early life stage from hatching to adult emergence was critical. It was possible to select a cultivar that is resistant to mites under a real cultivation environment by observing the internal structure of the leaf. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  17. Chlorophyll and its degradation products in the two-spotted spider mite, Tetranychus urticae: observations using epifluorescence and confocal laser scanning microscopy.

    Science.gov (United States)

    Occhipinti, Andrea; Maffei, Massimo E

    2013-10-01

    Chlorophyll and chlorophyll degradation products were observed in the two-spotted spider mite (Tetranychus urticae) using epifluorescence microscopy (EFM) and confocal laser scanning microscopy (CLSM). A clear red fluorescence (EFM) and a fluorescence induced by a laser wavelength of 650 nm (CLSM) were observed. In the lateral caeca, in the ventriculus and in the excretory organ, a bright light blue fluorescence was observed in close association with chlorophyll by using EFM. The same material can be localized with CLSM by using a laser with a wavelength of 488 nm. By comparison with synthetic guanine, this bright fluorescence is supposed to be guanine. The presence of guanine fluorescence in the mite pellets confirms this hypothesis. A possible mechanism for guanine formation is discussed.

  18. Sublethal effects of spirodiclofen, abamectin and pyridaben on life-history traits and life-table parameters of two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae).

    Science.gov (United States)

    Saber, Moosa; Ahmadi, Zeinab; Mahdavinia, Gholamreza

    2018-05-01

    Two-spotted spider mite, Tetranychus urticae Koch, is one of the economically most important pests on a wide range of crops in greenhouses and orchards worldwide. Control of T. urticae has been largely based on the use of acaricides. Sublethal effects of spirodiclofen, pyridaben and abamectin were studied on life-table parameters of T. urticae females treated with the acaricides. LC 25 values of spirodiclofen, abamectin and pyridaben (3.84, 0.04 and 136.96 µg a.i./ml, respectively) were used for sublethal studies. All acaricides showed significant effects on T. urticae biological parameters including developmental time, survival rate, and fecundity. The females treated with spirodiclofen, abamectin and pyridaben at LC 25 exhibited significantly reduced net reproductive rate (R 0 ), finite rate of increase (λ) and intrinsic rate of increase (r). The intrinsic rate of increase in spirodiclofen, abamectin and pyridaben treated groups and control were 0.0138, 0.0273, 0.039 and 0.2481 female offspring per female per day, respectively. The results indicated that sublethal concentrations of tested pesticides strongly affected the life characteristics of spider mite and consequently may influence mite population growth in future generations.

  19. CONFIRMATION OF PRESENCE OF A PREDATORY GALL MIDGE, Feltiella acarisuga, (Vallot, 1827 AND STAPHYLINID PREDATOR Oligota oviformis Casey, 1893 OF A TWO SPOTTED SPIDER MITE (Tetranychus urticae, Koch, 1836 IN SLOVENIA

    Directory of Open Access Journals (Sweden)

    Katarina KOS

    2018-04-01

    Full Text Available The two spotted spider mite, Tetranychus urticae C. L. Koch, 1836 is one of the most important pests of greenhouse crops worldwide. Due to its polyphagic range of hosts and rapid development it forms great populations and as such represents a suitable host/prey for lots of natural enemies usable in biological control. Most commonly used predators of Tetranychid mites are predatory mites (Phytoseiulus persimilis Athias-Henriot, 1957, Amblyseius swirskii Athias-Henriot, 1962 ,…, but among most voracious predators is the larva of a predatory gall midge, Feltiella acarisuga (Vallot, 1827 that was found also in greenhouses of the Biotechnical Faculty in Ljubljana on eggplant leaves in 2017. Besides the predatory gall midge also another predator, staphylinid Oligota oviformis Casey, 1893 beetles and larvae were found in great numbers. After positive identification of F. acarisuga found naturally in Slovenia, it can be added to the list of indigenous species of natural enemies and thus can be used in biological control programs in greenhouse crop protection against spider mites.

  20. Spectral response of spider mite infested cotton: Mite density and miticide rate study

    Science.gov (United States)

    Two-spotted spider mites are important pests in many agricultural systems. Spider mites (Acari: Tetranychidae) have been found to cause economic damage in corn, cotton, and sorghum. Adult glass vial bioassays indicate that Temprano™ (abamectin) is the most toxic technical miticide for adult two-spot...

  1. Learned predation risk management by spider mites

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    Thomas eHackl

    2014-09-01

    Full Text Available Predation is a prime selective force shaping prey behavior. Investment in anti-predator behavior is traded-off against time and energy for other fitness-enhancing activities such as foraging or reproduction. To optimize this benefit/cost trade-off, prey should be able to innately and/or by experience modulate their behavior to the level of predation risk. Here, we assessed learned predation risk management in the herbivorous two-spotted spider mite Tetranychus urticae. We exposed spider mites coming from benign (naïve or high immediate predation risk (experienced environments to latent and/or no risk and assessed their site choice, activity and oviposition. Benign environments were characterized by the absence of any predator cues, high immediate risk environments by killed spider mites, physical presence of the predatory mite Phytoseiulus persimilis and associated chemosensory traces left on the surface, and latent risk environments by only predator traces. In the no-choice experiment both naïve and experienced spider mites laid their first egg later on leaves with than without predator traces. Irrespective of predator traces presence/absence, experienced mites laid their first egg earlier than naïve ones did. Naïve spider mites were more active, indicating higher restlessness, and laid fewer eggs on leaves with predator traces, whereas experienced mites were less active and laid similar numbers of eggs on leaves with and without predator traces. In the choice experiment both naïve and experienced spider mites preferentially resided and oviposited on leaves without predator traces but experienced mites were less active than naïve ones. Overall, our study suggests that spider mites experienced with high predation risk behave bolder under latent risk than naïve spider mites. Since predator traces alone do not indicate immediate risk, we argue that the attenuated anti-predator response of experienced spider mites represents adaptive learned

  2. Trophic Interactions between Generalist Predators and the Two Spotted Spide Mite, Tetranychus urticae in, Strawberry

    DEFF Research Database (Denmark)

    Jacobsen, Stine Kramer

    The two spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is a major cause of pest damage worldwide. Its host range includes among many the strawberry crop, a high value crop in Denmark as well as in many other temperate and subtropical regions. Chemical control of T. urticae...... occurrence and diversity of predatory insects and predatory mites in Danish strawberry fields and surrounding vegetation is lacking, as is the knowledge of the potential of generalist insect predators to control T. urticae. The overall objective of this PhD thesis was to investigate the trophic interactions...... between natural enemies, in particular generalist predators and the two spotted spider mite, T. urticae, in strawberry. This was done by investigating interactions of T. urticae and its natural enemies as influenced by cropping practice and the surrounding vegetation (Manuscript I) as well as more...

  3. Spider mite control and resistance management: does a genome help?

    NARCIS (Netherlands)

    Van Leeuwen, T.; Dermauw, W.; Grbic, M.; Tirry, L.; Feyereisen, R.

    2012-01-01

    The complete genome of the two-spotted spider mite, Tetranychus urticae, has been reported. This is the first sequenced genome of a highly polyphagous and resistant agricultural pest. The question as to what the genome offers the community working on spider mite control is addressed.

  4. Active optical sensor assessment of spider mite damage on greenhouse beans and cotton

    Science.gov (United States)

    The two-spotted spider mite, Tetranychus urticae Koch is an important pest of cotton in mid-southern United States and causes yield reduction, and deprivation in fiber fitness. A greenhouse colony of the spider mite was used to infest cotton and pinto beans at the three-leaf and trifoliate stages, r...

  5. Tomato whole genome transcriptional response to Tetranychus urticae identifies divergence of spider mite-induced responses between tomato and Arabidopsis

    NARCIS (Netherlands)

    Martel, C.; Zhurov, V.; Navarro, M.; Martinez, M.; Cazaux, M.; Auger, P.; Migeon, A.; Santamaria, M.E.; Wybouw, N.; Diaz, I.; Van Leeuwen, T.; Navajas, M.; Grbic, M.; Grbic, V.

    2015-01-01

    The two-spotted spider mite Tetranychus urticae is one of the most significant mite pests in agriculture, feeding on more than 1,100 plant hosts, including model plants Arabidopsis thaliana and tomato, Solanum lycopersicum. Here, we describe timecourse tomato transcriptional responses to spider mite

  6. Abundance, Genetic Diversity and Persistence of Metarhizium Spp. Fungi from Soil of Strawberry Crops and Their Potential as Biological Control Agents against the Two-Spotted Spider Mite Tetranychus urticae

    DEFF Research Database (Denmark)

    Castro, Thiago Rodriguesde

    The growing demand for strawberries has imposed challenges, especially regarding the control of pests. Many farmers report problems with reduced chemical control efficiency, probably due to selection of resistant populations of insects and mites. An alternative is the use of biological control...... agent were performed, but this bulk of knowledge is in remarkable contrast to the lack of research on the fundamental ecology of Metarhizium in agroecosystems. This thesis aimed to evaluate the establishment, persistence and dispersal of these entomopathogenic fungi in strawberry crop soil...... in Inconfidentes, Minas Gerais, Brazil; and to study the diversity and abundance of species of Metarhizium isolated from organic and conventional strawberry crop soils, and from the field margins in Brazil and Denmark. The effectiveness of new species of Metarhizium recently found in Brazil, was evaluated against...

  7. Gamma irradiation as a quarantine treatment for spider mites (Acarina: tetranychidae) in horticultural products

    International Nuclear Information System (INIS)

    Ignatowicz, S.; Banasik-Solgala, K.

    1999-01-01

    The carmine spider mite, Tetranychus cinnabarinus (Boisd.), and the two-spotted spider mite, Tetranychus urticae Koch, are closely related species of tetranychid mites (Acarina, Tetranychidae) that respond to gamma irradiation in a similar way. Eggs of both species exposed to gamma radiation early in embryonic development were considerably more susceptible to irradiation than older eggs. The tolerance of eggs to gamma radiation increased in 3-4-day-old eggs, when eye-spots were formed. Nymphs were more resistant to gamma radiation than eggs and larvae. Deteriorative effects of irradiation treatment were reflected in the immatures by their mortality in subsequent developmental stages. A positive relationship between dosage and the percent egg mortality or the mortality of subsequent stages was usually found when the immature stages were irradiated. The sex ratio of adults developed from irradiated eggs, larvae, and nymphs was affected by the irradiation treatment; the ratio was usually skewed towards males. Irradiation of females resulted in increased mortality, lowered fecundity, reduced egg viability, and sex ratio distortion in their progeny. Two-day-old females of the carmine spider mite and the two-spotted spider mite irradiated with 200 or 300 Gy lived as long as the controls. Mortality occurred after 3 weeks. The number of eggs laid by irradiated females of spider mites was considerably lower than in the control, and it decreased as the absorbed dose increased. The higher the dose of gamma radiation applied to adults of the spider mites (the parental generation, P), the higher the mortality of the F1 mites during their embryonic development. Viability of eggs laid by irradiated females of spider mites mated with irradiated males was significantly reduced. Young females treated with a dose of 0.2 kGy produced 40-50% nonviable eggs, while control mites produced only 6.0-6.6% nonviable eggs. A dose of 0.3 kGy caused high mortality of eggs; 88% and 97% nonviable

  8. Active optical sensor assessment of spider mite damage on greenhouse beans and cotton.

    Science.gov (United States)

    Martin, Daniel E; Latheef, Mohamed A

    2018-02-01

    The two-spotted spider mite, Tetranychus urticae Koch, is an important pest of cotton in mid-southern USA and causes yield reduction and deprivation in fiber fitness. Cotton and pinto beans grown in the greenhouse were infested with spider mites at the three-leaf and trifoliate stages, respectively. Spider mite damage on cotton and bean canopies expressed as normalized difference vegetation index indicative of changes in plant health was measured for 27 consecutive days. Plant health decreased incrementally for cotton until day 21 when complete destruction occurred. Thereafter, regrowth reversed decline in plant health. On spider mite treated beans, plant vigor plateaued until day 11 when plant health declined incrementally. Results indicate that pinto beans were better suited as a host plant than cotton for rearing T. urticae in the laboratory.

  9. Controle biológico do ácaro rajado com ácaros predadores fitoseídeos (Acari: Tetranychidae, Phytoseiidae em culturas de pepino e morango Biological control of the two-spotted spider mite (Acari: Tetranychidae, Phytoseiidae in cucumber and strawberry crops

    Directory of Open Access Journals (Sweden)

    M.A. Watanabe

    1994-04-01

    Full Text Available O ácaro rajado, Tetranychus urticae Koch, é considerado uma das principais pragas de hortaliças e várias outras culturas no Brasil, em áreas onde um considerável volume de acaricidas é anualmente empregado no seu controle. O objetivo deste trabalho foi testar a viabilidade técnica do emprego dos fitoseídeos Amblyseius idaeus (Denmark & Muma e Phytoseudus macropilis (Banks, comum ente encontrados no Brasil, no controle de T. urticae em pepino e morangueiro em Jaguaríúna,SP. Utilizou-se o delineamento experimental em blocos casualizados, com 4 repetições e 4 tratamentos (T1-T4 para o pepino e 5 tratamentos para o morangueiro (T1-T5: T1, testemunha; T2, pulverizações semanais de Malation para a exclusão de predadores nativos; T3, liberações periódicas de A.idaeus; T4, liberações periódicas de P.macropilis; T5, pulverizações semanais de avermectina para a exclusão de ácaros fitófagos e predadores nativos. Apenas A.idaeus se estabeleceu na cultura de pepino, reduzindo significativamente a população de T. urticae. Ambas espécies de predadores se estabeleceram na cultura do morango e reduziram significativamente a população de T.urticae.The two-spotted spider mite, Tetranychus urticae Koch, is considered one of the main pests of horticultural and other crops in Brazil, in areas where a considerable volume of acaricides is annually used for its control. The objective of this work was to test the technical viability of using phytoseiids Amblyseius idaeus (Denmark & Muma and Phytoseudus macropilis (Banks, commonly found in Brazil, to control T .urticae in cucumber and strawberry crops in Jaguaríúna,SP. A randomized complete block design was used, with 4 replicates and 4 treatments for cucumber (T1-T4 and 5 treatments for strawberry crops (T1-T5: T1, control; T2, weekly sprays of malathion for exclusion of native predators; T3, periodical releases of A.idaeus; T4, periodical releases of P. macropilis; T5, weekly sprays of

  10. Induction of indirect defence against spider-mites in uninfested lima bean leaves.

    NARCIS (Netherlands)

    Takabayashi, J.; Dicke, M.; Posthumus, M.A.

    1991-01-01

    Headspace analyses of uninfested Lima bean (Phaseolus lunatus) leaves show an absence of or only trace amounts of the terpenoids (E)--ocimene and (E)-4,8-dimethyl-1,3,7-nonatriene. Upon infestation by two-spotted spider-mites (Tetranychus urticae), Lima bean leaves produce (E)--ocimene and

  11. Voluntary Falling in Spider Mites in Response to Different Ecological Conditions at Landing Points

    OpenAIRE

    Ohzora, Yousuke; Yano, Shuichi

    2011-01-01

    We examined voluntary-falling behaviour by adult females of the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) and one of its major predators Neoseiulus californicus McGregor (Acari: Phytoseiidae). Experiments were conducted using a setup in which mites could only move onto one of two landing points by falling. Significantly more T. urticae females fell onto available food leaves compared to non-food or heavily infested leaves, whereas significantly fewer females fell...

  12. Genetic diversity analysis of various red spider mite- resistant ...

    African Journals Online (AJOL)

    User

    2011-05-02

    May 2, 2011 ... 3Key Laboratory of Plant Breeding and Genetics, Sichuan Agricultural University, Ya'an, 625014, P. R. ... Random amplified polymorphic DNA (RAPD) is a DNA ..... spider mite-resistant, bumper, high-quality and disease-.

  13. A horizontally transferred cyanase gene in the spider mite Tetranychus urticae is involved in cyanate metabolism and is differentially expressed upon host plant chang

    NARCIS (Netherlands)

    Wybouw, N.; Balabanidou, V.; Ballhorn, D.J.; Dermauw, W.; Grbić, M.; Vontas, J.; Van Leeuwen, T.

    2012-01-01

    The genome of the phytophagous two-spotted spider mite Tetranychus urticae was recently sequenced, representing the first complete chelicerate genome, but also the first genome of a highly polyphagous agricultural pest. Genome analysis revealed the presence of an unexpected high number of cases of

  14. Low temperature–scanning electron microscopy to evaluate morphology and predation of Scolothrips sexmaculatus Pergande (Thysanoptera: Thripidae) against spider mites (Acari: Tetranychidae: Tetranychus species)

    Science.gov (United States)

    This paper evaluates the potential usefulness of low temperature-scanning electron microscopy (LT-SEM) to evaluate morphology and predation behavior of the six-spotted thrips (Scolothrips sexmaculatus Pergande) against the two-spotted spider mite (Tetranychus urticae (Koch)). Morphological features...

  15. Investigations on the Effects of Five Different Plant Extracts on the Two-Spotted Mite Tetranychus urticae Koch (Arachnida: Tetranychidae

    Directory of Open Access Journals (Sweden)

    Pervin Erdogan

    2012-01-01

    Full Text Available Two-spotted mite, Tetranychus urticae Koch (Arac.: Tetranychidae, is an economic pest worldwide including Turkey, causing serious damage to vegetables, flowers, and fruit crops. In recent years, broad-spectrum insecticides/miticides have been used to control this pest in Turkey. Control is difficult mainly due to resistance to conventional pesticides. This study was conducted to determine efficacy of pesticides extracted from five different plants [i.e., Allium sativum L. (Amaryllidaceae, Rhododendron luteum S. (Ericaceae, Helichrysum arenarium L. (Asteraceae, Veratrum album L. (Liliaceae, and Tanacetum parthenium L. (Asteraceae] against this mite. Bioassays were tested by two different methods to determine the effects of varying concentrations. Experiments were performed using 3 cm diameter leaf disk from unsprayed bean plants (Phaseolus vulgaris L.. In addition, the effects of the extracts on reproduction and oviposition were investigated. The extract yielded high mortality. In the lowest-concentration bioassays, the adult mites laid lower numbers of eggs compared to the untreated control. No ovicidal effect was observed.

  16. Induction of direct and indirect plant responses by jasmonic acid, low spider mite densities, or a combination of jasmonic acid treatment and spider mite infestation.

    Science.gov (United States)

    Gols, Rieta; Roosjen, Mara; Dijkman, Herman; Dicke, Marcel

    2003-12-01

    Jasmonic acid (JA) and the octadecanoid pathway are involved in both induced direct and induced indirect plant responses. In this study, the herbivorous mite, Tetranychus urticae, and its predator, Phytoseiulus persimilis, were given a choice between Lima bean plants induced by JA or spider mites and uninduced control plants. Infestation densities resulting in the induction of predator attractants were much lower than thus far assumed, i.e., predatory mites were significantly attracted to plants that were infested for 2 days with only one or four spider mites per plant. Phytoseiulus persimilis showed a density-dependent response to volatiles from plants that were infested with different numbers of spider mites. Similarly, treating plants with increasing concentrations of JA also led to increased attraction of P. persimilis. Moreover, the duration of spider mite infestation was positively correlated with the proportion of predators that were attracted to mite-infested plants. A pretreatment of the plants with JA followed by a spider mite infestation enhanced the attraction of P. persimilis to plant volatiles compared to attraction to volatiles from plants that were only infested with spider mites and did not receive a pretreatment with JA. The herbivore, T. urticae preferred leaf tissue that previously had been infested with conspecifics to uninfested leaf tissue. In the case of choice tests with JA-induced and control leaf tissue, spider mites slightly preferred control leaf tissue. When spider mites were given a choice between leaf discs induced by JA and leaf discs damaged by spider mite feeding, they preferred the latter. The presence of herbivore induced chemicals and/or spider mite products enhanced settlement of the mites, whereas treatment with JA seemed to impede settlement.

  17. Role of environmental exposure to spider mites in the sensitization and the clinical manifestation of asthma and rhinitis in children and adolescents living in rural and urban areas.

    Science.gov (United States)

    Kim, Y-K; Chang, Y-S; Lee, M-H; Hong, S-C; Bae, J-M; Jee, Y-K; Chun, B-R; Cho, S-H; Min, K-U; Kim, Y-Y

    2002-09-01

    Spider mites such as the citrus red mite and the two-spotted spider mite have been demonstrated to be important allergens for fruit cultivating farmers. To evaluate the role of environmental exposure to spider mites in the sensitization and the clinical manifestations of asthma and rhinitis in children and adolescents living in urban and rural areas. A total of 16,624 subjects (aged 7 to 18 years) living in urban (metropolitan and non-metropolitan) and rural areas (apple orchards and citrus orchards) in Korea were evaluated by questionnaire and skin prick test for 11 common aeroallergens, including citrus red mite (CRM) and two-spotted spider mite (TSM). The positive skin response rates to TSM were 4.2% of 1,563 metropolitan subjects, 3.8% of 5,568 non-metropolitan subjects and 6.5% of 1,464 subjects living nearby apple farms, and that to CRM 15.6% of 8,029 living nearby citrus farms. The prevalence of current wheeze and rhinitis as reported on a questionnaire was higher among those with a history of visiting fruit farms once or more per year than among those without it (10% vs. 7.1%, 32.8% vs. 26.7%, for wheezing and rhinitis, respectively). Among those with wheezing or rhinitis, the positive skin responses to TSM or CRM were also higher among those with a history of visiting fruit farms than among those without one (11.2% vs. 6.6%, 13.0% vs. 6.6%, respectively), although the positive skin responses to house dust mites were similar in the both groups. Spider mites are common sensitizing allergens in children and adolescents exposed to them, and environmental exposure to these mites may represent an important risk factor in the sensitization and the clinical manifestations of asthma and rhinitis in children and adolescents living in rural and urban areas.

  18. Evaluation of predatory mites and Acramite for control of twospotted spider mites in strawberries in north central Florida.

    Science.gov (United States)

    Rhodes, Elena M; Liburd, Oscar E

    2006-08-01

    Greenhouse and field experiments were conducted from 2003 to 2005 to determine the effectiveness of two predatory mite species, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), and a reduced-risk miticide, Acramite 50 WP (bifenazate), for control of twospotted spider mite, Tetranychus urticae Koch, in strawberries (Fragaria x ananassa Duchesne). In greenhouse tests, three treatments consisting of releases of P. persimilis, N. californicus, and an untreated control were evaluated. Both species of predatory mites significantly reduced twospotted spider mite numbers below those found in the control during the first 3 wk of evaluation. However, during week 4, twospotted spider mite numbers on the plants treated with P. persimilis increased and did not differ significantly from the control. Field studies used releases of P. persimilis and N. californicus, applications of Acramite, and untreated control plots. Both N. californicus and P. persimilis significantly reduced populations of twospotted spider mite below numbers recorded in the control plots. During the 2003-2004 field season P. persimilis took longer than N. californicus to bring the twospotted spider mite population under control (< 10 mites per leaflet). Acramite was effective in reducing twospotted spider mite populations below 10 mites per leaflet during the 2003-2004 field season but not during the 2004-2005 field season, possibly because of a late application. These findings indicate that N. californicus releases and properly timed Acramite applications are promising options for twospotted spider mite control in strawberries for growers in north Florida and other areas of the southeast.

  19. Growth analysis of cotton crops infested with spider mites. I. Light interception and radiation-use efficiency

    International Nuclear Information System (INIS)

    Sadras, V.O.; Wilson, L.J.

    1997-01-01

    Two-spotted spider mites (Tetranychus urticae Koch) are important pests of cotton (Gossypium hirsutum L.). The effects of mites on cotton photosynthesis have been investigated at the leaf and cytological level but not at the canopy level. Our objective was to quantify the effects of timing and intensity of infestation by mites on cotton radiation-use efficiency (RUE). Leaf area, light interception, RUE, canopy temperature, and leaf nitrogen concentration (LNC) were assessed during two growing seasons in crops artificially infested with mites between 59 and 127 d after sowing. Normal and okra-leaf cultivars were compared. A mite index (MI = natural log of the area under the curve of mite number vs thermal time) was used to quantify the cumulative effects of mites on RUE, LNC, and canopy temperature. Crop growth reduction due to mites was greater in early- than in late-infested crops Growth reduction was primarily due to reductions in RUE, but in the more severe treatments accelerated leaf senescence and, hence. reduced light interception also contributed to reductions in crop growth. At a given date, infested okra-leaf crops usually had greater RUE than their normal-leaf counterparts. Both plant types, however. responded similarly to a given level of mite infestation. The ability of the okra-leaf cultivar to maintain greater RUE levels can be attributed. therefore, to its relative inhospitality for the development of mite colonies rather than to an intrinsically greater capacity to maintain photosynthesis under mite damage. Canopy temperature, LNC, and RUE showed a similar, biphasic pattern of response to Ml. In the first phase, response variables were almost unaffected by mites. In the second phase, there was a marked decline in RUE and LNC and a marked increase in canopy temperature with increasing MI. These results suggest (i) some degree of compensatory photosynthesis at low to moderate levels of mite infestation, and (ii) reductions in RUE of mite

  20. Environmental Engineering Approaches toward Sustainable Management of Spider Mites.

    Science.gov (United States)

    Suzuki, Takeshi

    2012-10-26

    Integrated pest management (IPM), which combines physical, biological, and chemical control measures to complementary effect, is one of the most important approaches to environmentally friendly sustainable agriculture. To expand IPM, we need to develop new pest control measures, reinforce existing measures, and investigate interactions between measures. Continued progress in the development of environmental control technologies and consequent price drops have facilitated their integration into plant production and pest control. Here I describe environmental control technologies for the IPM of spider mites through: (1) the disturbance of photoperiod-dependent diapause by artificial light, which may lead to death in seasonal environments; (2) the use of ultraviolet radiation to kill or repel mites; and (3) the use of water vapor control for the long-term cold storage of commercially available natural enemies. Such environmental control technologies have great potential for the efficient control of spider mites through direct physical effects and indirect effects via natural enemies.

  1. Beyond Predation: The Zoophytophagous Predator Macrolophus pygmaeus Induces Tomato Resistance against Spider Mites.

    Directory of Open Access Journals (Sweden)

    Maria L Pappas

    Full Text Available Many predatory insects that prey on herbivores also feed on the plant, but it is unknown whether plants affect the performance of herbivores by responding to this phytophagy with defence induction. We investigate whether the prior presence of the omnivorous predator Macrolophus pygmaeus (Rambur on tomato plants affects plant resistance against two different herbivore species. Besides plant-mediated effects of M. pygmaeus on herbivore performance, we examined whether a plant defence trait that is known to be inducible by herbivory, proteinase inhibitors (PI, may also be activated in response to the interactions of this predator with the tomato plant. We show that exposing tomato plants to the omnivorous predator M. pygmaeus reduced performance of a subsequently infesting herbivore, the two-spotted spider mite Tetranychus urticae Koch, but not of the greenhouse whitefly Trialeurodes vaporariorum (Westwood. The spider-mite infested tomato plants experience a lower herbivore load, i.e., number of eggs deposited and individuals present, when previously exposed to the zoophytophagous predator. This effect is not restricted to the exposed leaf and persists on exposed plants for at least two weeks after the removal of the predators. The decreased performance of spider mites as a result of prior exposure of the plant to M. pygmaeus is accompanied by a locally and systemically increased accumulation of transcripts and activity of proteinase inhibitors that are known to be involved in plant defence. Our results demonstrate that zoophytophagous predators can induce plant defence responses and reduce herbivore performance. Hence, the suppression of populations of certain herbivores via consumption may be strengthened by the induction of plant defences by zoophytophagous predators.

  2. The sejugal furrow in camel spiders and acariform mites

    Directory of Open Access Journals (Sweden)

    Dunlop, Jason A.

    2012-07-01

    Full Text Available Camel spiders (Arachnida: Solifugae are one of the arachnid groups characterised by a prosomal dorsal shield composed of three distinct elements: the pro-, meso- and metapeltidium. These are associated respectively with prosomal appendages one to four, five, and six. What is less well known, although noted in the historical literature, is that the coxae of the 4th and 5th prosomal segments (i.e. walking legs 2 and 3 of camel spiders are also separated ventrally by a distinct membranous region, which is absent between the coxae of the other legs. We suggest that this essentially ventral division of the prosoma specifically between coxae 2 and 3 is homologous with the so-called sejugal furrow (the sejugal interval sensu van der Hammen. This division constitutes a fundamental part of the body plan in acariform mites (Arachnida: Acariformes. If homologous, this sejugal furrow could represent a further potential synapomorphy for (Solifugae + Acariformes; a relationship with increasing morphological and molecular support. Alternatively, outgroup comparison with sea spiders (Pycnogonida and certain early Palaeozoic fossils could imply that the sejugal furrow defines an older tagma, derived from a more basal grade of organisation. In this scenario the (still divided prosoma of acariform mites and camel spiders would be plesiomorphic. This interpretation challenges the textbook arachnid character of a peltidium (or ‘carapace’ covering an undivided prosoma.

  3. Integrated pest management of two-spotted mite Tetranychus urticae on greenhouse roses using petroleum spray oil and the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Nicetic; Watson, D M; Beattie, G A; Meats, A; Zheng, J

    2001-01-01

    From 1995 to 1999, four experiments were conducted on greenhouse roses to assess the effectiveness of the nC24 petroleum spray oil (PSO), D-C-Tron Plus, against two-spotted mite, Tetranychus urticae Koch (Acarina: Tetranychidae), and to determine how the oil could be most efficiently and effectively used in combination with the predatory mite Phytoseiulus persimilis Athias-Henriot (Acarina: Phytoseiidae) in an integrated pest management program. The results showed that 0.5% PSO applied fortnightly to roses gave excellent protection from T urticae infestation when the mite population was not already established. However, PSO applied after roses were infested with T. urticae above the economic threshold only stabilised populations without reducing them below that threshold. Populations of P. persimilis in the upper and lower canopies were unchanged after two sprays of PSO at 7-day intervals, and application of PSO to the upper canopy was as effective in controlling T. urticae in the presence of P persimilis as spraying the entire plant. Combining PSO with P. persimilis gave better control of T. urticae than using P. persimilis alone. The most cost-effective use of PSO in the presence of P. persimilis is, therefore, to apply spray only to the upper canopy. This will not affect control of powdery mildew with PSO. Comparison of a control program for T urticae based on the monitored use of synthetic miticides with that based on calendar application of PSO revealed that both gave equally effective control. The benefits of combining PSO and P. persimilis in an integrated pest management program for T. urticae on roses over a program based on synthetic fungicides are discussed.

  4. Differences among plant species in acceptance by the spider mite Tetranychus urticae Koch

    NARCIS (Netherlands)

    Boom, van den C.E.M.; Beek, van T.A.; Dicke, M.

    2003-01-01

    The spider mite Tetranychus urticae Koch has a broad range of host plants. However, the spider mite does not accept all plants to the same degree because of differences in nutritive and toxic constituents. Other factors, such as the induction of secondary metabolites, the morphology of a leaf

  5. Intercropping With Fruit Trees Increases Population Abundance and Alters Species Composition of Spider Mites on Cotton.

    Science.gov (United States)

    Li, Haiqiang; Pan, Hongsheng; Wang, Dongmei; Liu, Bing; Liu, Jian; Zhang, Jianping; Lu, Yanhui

    2018-05-05

    With the recent increase in planting of fruit trees in southern Xinjiang, the intercropping of fruit trees and cotton has been widely adopted. From 2014 to 2016, a large-scale study was conducted in Aksu, an important agricultural area in southern Xinjiang, to compare the abundance and species composition of spider mites in cotton fields under jujube-cotton, apple-cotton, and cotton monocrop systems. The abundance of spider mites in cotton fields under both intercropping systems was generally higher than in the cotton monocrop. The species composition of spider mites also differed greatly between cotton intercropped with apple or jujube compared to the cotton monocrop. The relative proportion of Tetranychus truncates Ehara (Acari: Tetranychidae) in the species complex generally increased while that of another spider mite, Tetranychus dunhuangensis Wang (Acari: Tetranychidae), decreased under fruit tree-cotton systems. More attention should be paid to the monitoring and management of spider mites, especially T. truncates in this important region of China.

  6. Prey preference of the phytoseiid mite Typhlodromus pyri. 1. Response to volatile kairomones.

    NARCIS (Netherlands)

    Dicke, M.

    1988-01-01

    Using a Y-tube olfactometer, a study has been made of the response of females of the predatory miteTyphlodromus pyri Scheuten (Acarina: Phytoseiidae) to volatile kairomones of three prey species: the European red spider mite (Panonychus ulmi (Koch)), the two-spotted spider mite (Tetranychus urticae

  7. Population survey of phytoseiid mites and spider mites on peach leaves and wild plants in Japanese peach orchard.

    Science.gov (United States)

    Wari, David; Yamashita, Jun; Kataoka, Yoko; Kohara, Yoko; Hinomoto, Norihide; Kishimoto, Hidenari; Toyoshima, Shingo; Sonoda, Shoji

    2014-07-01

    A population survey of phytoseiid mites and spider mites was conducted on peach leaves and wild plants in Japanese peach orchards having different pesticide practices. The phytoseiid mite species composition on peach leaves and wild plants, as estimated using quantitative sequencing, changed during the survey period. Moreover, it varied among study sites. The phytoseiid mite species compositions were similar between peach leaves and some wild plants, such as Veronica persica, Paederia foetida, Persicaria longiseta, and Oxalis corniculata with larger quantities of phytoseiid mites, especially after mid-summer. A PCR-based method to detect the ribosomal ITS sequences of Tetranychus kanzawai and Panonychus mori from phytoseiid mites was developed. Results showed that Euseius sojaensis (specialized pollen feeder/generalist predator) uses both spider mites as prey in the field.

  8. Functional response of predatory thrips to two-spotted spider mite - influence of pesticides

    DEFF Research Database (Denmark)

    Pakyari, Hajar; Enkegaard, Annie

    2013-01-01

    A leaf disc bioassay was used to investigate the effects of abamectin and fenpropathrin on the functional response of an acarophagous thrips, Scolothrips longicornis Priesner, to eggs of Tetranychus urticae Koch at 25 ± 1°C, 60 ± 10% RH, 16:8 h (L:D). The type of the functional response differed....... The theoretical maximum number of prey attacked by the thrips was 49.67 and 23.67 eggs per day for females and males, respectively; both maxima were attained in the control treatment. These values were reduced for males exposed to full doses of either pesticide and for females exposed to both half and full doses...

  9. Fundamental aspects of genetic control of the two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae)

    International Nuclear Information System (INIS)

    Feldmann, A.M.

    1979-01-01

    Radiobiological properties of Tetranychus urticae and other topics of genetic control have been evaluated. The induction by X-rays or fast neutrons of dominant lethals in mature sperm and of dominant lethals and recessive lethals in prophase-1 oocytes and the induction by both radiation types of chromosome mutations, recessive lethals and factors causing F 1 -infertility in sperm and oocytes, have been studied. From the results the optimal dose, radiation type and germ cell type could be chosen for obtaining either fully sterile males or substerile males, producing fully infertile F 1 -females. Also the most favourable conditions were determined for the induction of chromosome mutations with the lowest frequency of linked recessive lethals. The radiobiological properties of holokinetic chromosomes are extensively discussed. The successful displacement of the standard karyotype by a radiation arranged karyotype is presented and discussed in its relevance for practical application. (Auth./C.F.)

  10. From repulsion to attraction: species- and spatial context-dependent threat sensitive response of the spider mite Tetranychus urticae to predatory mite cues

    Science.gov (United States)

    Fernández Ferrari, M. Celeste; Schausberger, Peter

    2013-06-01

    Prey perceiving predation risk commonly change their behavior to avoid predation. However, antipredator strategies are costly. Therefore, according to the threat-sensitive predator avoidance hypothesis, prey should match the intensity of their antipredator behaviors to the degree of threat, which may depend on the predator species and the spatial context. We assessed threat sensitivity of the two-spotted spider mite, Tetranychus urticae, to the cues of three predatory mites, Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius andersoni, posing different degrees of risk in two spatial contexts. We first conducted a no-choice test measuring oviposition and activity of T. urticae exposed to chemical traces of predators or traces plus predator eggs. Then, we tested the site preference of T. urticae in choice tests, using artificial cages and leaves. In the no-choice test, T. urticae deposited their first egg later in the presence of cues of P. persimilis than of the other two predators and cue absence, indicating interspecific threat-sensitivity. T. urticae laid also fewer eggs in the presence of cues of P. persimilis and A. andersoni than of N. californicus and cue absence. In the artificial cage test, the spider mites preferred the site with predator traces, whereas in the leaf test, they preferentially resided on leaves without traces. We argue that in a nonplant environment, chemical predator traces do not indicate a risk for T. urticae, and instead, these traces function as indirect habitat cues. The spider mites were attracted to these cues because they associated them with the existence of a nearby host plant.

  11. Evolutionary Aspects of Acaricide-Resistance Development in Spider Mites

    Directory of Open Access Journals (Sweden)

    Masahiro (Mh. Osakabe

    2009-01-01

    Full Text Available Although the development of acaricide resistance in spider mites is a long-standing issue in agricultural fields, recent problems with acaricide resistance may be characterized by the development of complex- and/or multiresistance to acaricides in distinct classes. Such complexity of resistance is not likely to be a single mechanism. Pesticide resistance involves the microevolution of arthropod pests, and population genetics underlies the evolution. In this review, we address the genetic mechanisms of acaricide resistance evolution. We discuss genetic diversity and linkage of resistance genes, relationships between mite habitat and dispersal, and the effect of dispersal on population genetic structure and the dynamics of resistance genes. Finally, we attempt to present a comprehensive view of acaricide resistance evolution and suggest risks under globalization as well as possible approaches to managing acaricide resistance evolution or emergence.

  12. Volatile compounds from leaves of the African spider plant (Gynandropsis gynandra) with bioactivity against spider mite (Tetranychus urticae)

    DEFF Research Database (Denmark)

    Nyalala, Samuel Odeyo; Petersen, Mikael Agerlin; Grout, Brian William Wilson

    2013-01-01

    Previous studies have demonstrated that Gynandropsis gynandra emits acetonitrile as a foliar volatile from intact plants and isolated leaves, and that this compound is an effective spider mite repellent. This study has used gas chromatography–mass spectrometry to investigate volatile compounds...... emitted from homogenised G. gynandra leaves to evaluate their tissue acetonitrile content and to look for other compounds that might be exploited for the management of spider mites. Acetonitrile was absent from the homogenised tissues of five lines of G. gynandra, studied over two seasons. Thirteen...... volatile compounds were emitted by G. gynandra at significantly higher levels than mite-susceptible pot roses, including isothiocyanates, aldehydes, esters, alcohols and terpenes. Six representative compounds were selected to assess bioactivity. Spider mite populations were completely inactive after a 2¿h...

  13. Age-dependent male mating tactics in a spider mite-A life-history perspective.

    Science.gov (United States)

    Sato, Yukie; Rühr, Peter T; Schmitz, Helmut; Egas, Martijn; Blanke, Alexander

    2016-10-01

    Males often fight with rival males for access to females. However, some males display nonfighting tactics such as sneaking, satellite behavior, or female mimicking. When these mating tactics comprise a conditional strategy, they are often thought to be explained by resource holding potential (RHP), that is, nonfighting tactics are displayed by less competitive males who are more likely to lose a fight. The alternative mating tactics, however, can also be explained by life-history theory, which predicts that young males avoid fighting, regardless of their RHP, if it pays off to wait for future reproduction. Here, we test whether the sneaking tactic displayed by young males of the two-spotted spider mite can be explained by life-history theory. We tested whether young sneaker males survive longer than young fighter males after a bout of mild or strong competition with old fighter males. We also investigated whether old males have a more protective outer skin-a possible proxy for RHP-by measuring cuticle hardness and elasticity using nanoindentation. We found that young sneaker males survived longer than young fighter males after mild male competition. This difference was not found after strong male competition, which suggests that induction of sneaking tactic is affected by male density. Hardness and elasticity of the skin did not vary with male age. Given that earlier work could also not detect morphometric differences between fighter and sneaker males, we conclude that there is no apparent increase in RHP with age in the mite and age-dependent male mating tactics in the mite can be explained only by life-history theory. Because it is likely that fighting incurs a survival cost, age-dependent alternative mating tactics may be explained by life-history theory in many species when reproduction of old males is a significant factor in fitness.

  14. Whiteflies interfere with indirect plant defense against spider mites in Lima bean

    Science.gov (United States)

    Zhang, Peng-Jun; Zheng, Si-Jun; van Loon, Joop J. A.; Boland, Wilhelm; David, Anja; Mumm, Roland; Dicke, Marcel

    2009-01-01

    Plants under herbivore attack are able to initiate indirect defense by synthesizing and releasing complex blends of volatiles that attract natural enemies of the herbivore. However, little is known about how plants respond to infestation by multiple herbivores, particularly if these belong to different feeding guilds. Here, we report the interference by a phloem-feeding insect, the whitefly Bemisia tabaci, with indirect plant defenses induced by spider mites (Tetranychus urticae) in Lima bean (Phaseolus lunatus) plants. Additional whitefly infestation of spider-mite infested plants resulted in a reduced attraction of predatory mites (Phytoseiulus persimilis) compared to attraction to plants infested by spider mites only. This interference is shown to result from the reduction in (E)-β-ocimene emission from plants infested by both spider mites and whiteflies. When using exogenous salicylic acid (SA) application to mimic B. tabaci infestation, we observed similar results in behavioral and chemical analyses. Phytohormone and gene-expression analyses revealed that B. tabaci infestation, as well as SA application, inhibited spider mite-induced jasmonic acid (JA) production and reduced the expression of two JA-regulated genes, one of which encodes for the P. lunatus enzyme β-ocimene synthase that catalyzes the synthesis of (E)-β-ocimene. Remarkably, B. tabaci infestation concurrently inhibited SA production induced by spider mites. We therefore conclude that in dual-infested Lima bean plants the suppression of the JA signaling pathway by whitefly feeding is not due to enhanced SA levels. PMID:19965373

  15. Evaluation of dry-adapted strains of the predatory mite Neoseiulus californicus for spider mite control on cucumber, strawberry and pepper.

    Science.gov (United States)

    Palevsky, E; Walzer, A; Gal, S; Schausberger, P

    2008-06-01

    The goal of this study was to evaluate spider mite control efficacy of two dry-adapted strains of Neoseiulus californicus. Performance of these strains were compared to a commercial strain of Phytoseiulus persimilis on whole cucumber, pepper and strawberry plants infested with Tetranychus urticae at 50 +/- 5% RH. Under these dry conditions predators' performance was very different on each host plant. On cucumber, spider mite suppression was not attained by any of the three predators, plants 'burnt out' within 4 weeks of spider mite infestation. On strawberry, all predators satisfactorily suppressed spider mites yet they differed in short term efficacy and persistence. Phytoseiulus persimilis suppressed the spider mites more rapidly than did the BOKU and SI N. californicus strains. Both N. californicus strains persisted longer than did P. persimilis. The BOKU strain was superior to SI in population density reached, efficacy in spider mite suppression and persistence. On pepper, in the first 2 weeks of the experiment the BOKU strain was similar to P. persimilis and more efficacious in spider mite suppression than strain SI. Four weeks into the experiment the efficacy of P. persimilis dropped dramatically and was inferior to the SI and BOKU strains. Overall, mean predator density was highest on plants harbouring the BOKU strain, lowest on plants with P. persimilis and intermediate on plants with the SI strain. Implications for biocontrol of spider mites using phytoseiid species under dry conditions are discussed.

  16. The response of Phytoseiulus persimilis to spider mite-induced volatiles from gerbera: influence of starvation and experience

    NARCIS (Netherlands)

    Krips, O.E.; Willems, P.E.I.; Gols, R.; Posthumus, M.A.; Dicke, M.

    1999-01-01

    When leaves of the ornamental crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves

  17. Morphology of the olfactory system in the predatory mite Phytoseiulus persimilis

    NARCIS (Netherlands)

    van Wijk, M.; Wadman, W.J.; Sabelis, M.W.

    2006-01-01

    The predatory mite Phytoseiulus persimilis locates its prey, the two-spotted spider mite, by means of herbivore-induced plant volatiles. The olfactory response to this quantitatively and qualitatively variable source of information is particularly well documented. The mites perform this task with a

  18. Higher glandular trichome density in tomato leaflets and repellence to spider mites

    International Nuclear Information System (INIS)

    Maluf, Wilson Roberto; Inoue, Irene Fumi; Ferreira, Raphael de Paula Duarte; Gomes, Luiz Antonio Augusto; Castro, Evaristo Mauro de; Cardoso, Maria das Gracas

    2007-01-01

    The objective of this work was to evaluate the feasibility of selection for higher glandular trichome densities, as an indirect criterion of selection for increasing repellence to spider mites Tetranychus urticae, in tomato populations derived from an interspecific cross between Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Trichome densities were evaluated in 19 genotypes, including 12 from advanced backcross populations, derived from the original cross L. esculentum x L. hirsutum var. glabratum PI 134417. Counts were made both on the adaxial and abaxial leaf surfaces, and trichomes were classified into glandular types IV and VI, other glandular types (types I+VII), and nonglandular types. Mite repellence was measured by distances walked by mites onto the tomato leaf surface after 20, 40 and 60 min. Spider mite repellence biotests indicated that higher densities of glandular trichomes (especially type VI) decreased the distances walked by the mites onto the tomato leaf surface. Selection of plants with higher densities of glandular trichomes can be an efficient criterion to obtain tomato genotypes with higher resistance (repellence) to spider mites. (author)

  19. Effect of aqueous plant extracts on tea red spider mite, Oligonychus ...

    African Journals Online (AJOL)

    Four aqueous plant extracts (APEs) of Acorus calamus (L), Xanthium strumarium (L), Polygonum hydropiper (L) and Clerodendron infortunatum (Gaertn) were evaluated under both laboratory and field conditions at 2.5, 5.0 and 10.0% (w/v) concentrations against tea red spider mite, Oligonychus coffeae (Nietner). Also, the ...

  20. Role of cucurbitacin C in resistance to spider mite (Tetranychus urticae) in cucumber (Cucumber sativus L.)

    NARCIS (Netherlands)

    Balkema-Boomstra, A.G.; Zijlstra, S.; Verstappen, F.W.A.; Inggamer, H.; Mercke, P.

    2003-01-01

    Cucurbitacins are bitter triterpenoid compounds that are toxic to most organisms and occur widely in wild and cultivated Cucurbitaceae. The only cucurbitacin identified in Cucumis sativus is cucurbitacin C. The bitter taste of cucumber has been correlated with resistance to the spider mite

  1. The role of horizontally transferred genes in the xenobiotic adaptations of the spider mite Tetranychus urticae

    NARCIS (Netherlands)

    Wybouw, N.R.

    2015-01-01

    Plant feeding arthropods adapt in diverse ways to dietary plant toxins. The genetic basis of these adaptations is not well characterized, especially in non-insect lineages. Using the sequenced genome of the herbivorous spider mite Tetranychus urticae as a starting point, this work aimed at

  2. Effects of Euseius stipulatus on establishment and efficacy in spider mite suppression of Neoseiulus californicus and Phytoseiulus persimilis in clementine.

    Science.gov (United States)

    Abad-Moyano, Raquel; Urbaneja, Alberto; Hoffmann, Daniela; Schausberger, Peter

    2010-04-01

    The two-spotted spider mite, Tetranychus urticae, is one of the most problematic phytophagous pests in Spanish clementine orchards. The most abundant predatory mites in this ecosystem are Euseius stipulatus, Phytoseiulus persimilis and Neoseiulus californicus. Euseius stipulatus is dominant but poorly adapted to utilize T. urticae as prey. It mainly persists on pollen and citrus red mite, Panonychus citri. A recent study suggested that the more efficacious T. urticae predators P. persimilis and N. californicus are negatively affected by lethal and non-lethal intraguild interactions with E. stipulatus. Here, we investigated the potential of N. californicus and P. persimilis to colonize and thrive on young clementine trees infested by T. urticae in presence and absence of E. stipulatus. Presence of E. stipulatus interfered with establishment and abundance of P. persimilis and negatively affected the efficacy of N. californicus in T. urticae suppression. In contrast, the abundance of E. stipulatus was not affected by introduction of a second predator. Trait-mediated effects of E. stipulatus changing P. persimilis and N. californicus behavior and/or life history were the most likely explanations for these outcomes. We conclude that superiority of E. stipulatus in intraguild interactions may indeed contribute to the currently observed predator species composition and abundance, rendering natural control of T. urticae in Spanish clementine orchards unsatisfactory. Nonetheless, stronger reduction of T. urticae and/or plant damage in the predator combination treatments as compared to E. stipulatus alone indicates the possibility to improve T. urticae control via repeated releases of N. californicus and/or P. persimilis.

  3. Differential Timing of Spider Mite-Induced Direct and Indirect Defenses in Tomato Plants1[w

    Science.gov (United States)

    Kant, Merijn R.; Ament, Kai; Sabelis, Maurice W.; Haring, Michel A.; Schuurink, Robert C.

    2004-01-01

    Through a combined metabolomics and transcriptomics approach we analyzed the events that took place during the first 5 d of infesting intact tomato (Lycopersicon esculentum) plants with spider mites (Tetranychus urticae). Although the spider mites had caused little visible damage to the leaves after 1 d, they had already induced direct defense responses. For example, proteinase inhibitor activity had doubled and the transcription of genes involved in jasmonate-, salicylate-, and ethylene-regulated defenses had been activated. On day four, proteinase inhibitor activity and particularly transcript levels of salicylate-regulated genes were still maintained. In addition, genes involved in phospholipid metabolism were up-regulated on day one and those in the secondary metabolism on day four. Although transcriptional up-regulation of the enzymes involved in the biosynthesis of monoterpenes and diterpenes already occurred on day one, a significant increase in the emission of volatile terpenoids was delayed until day four. This increase in volatile production coincided with the increased olfactory preference of predatory mites (Phytoseiulus persimilis) for infested plants. Our results indicate that tomato activates its indirect defenses (volatile production) to complement the direct defense response against spider mites. PMID:15122016

  4. The maintenance of genetic variation for oviposition rate in two-spotted spider mites: inferences from artificial selection

    NARCIS (Netherlands)

    Tien, N.S.H.; Sabelis, M.W.; Egas, M.

    2010-01-01

    Despite the directional selection acting on life-history traits, substantial amounts of standing variation for these traits have frequently been found. This variation may result from balancing selection (e.g., through genetic trade-offs) or from mutation-selection balance. These mechanisms affect

  5. Biological and ecological characterization of two mites (Tetranychus Urticae and Phytoseiulus Persimilis) occurring in some agro-ecosystems; Caratterizzazione biologica ed ecologica di due acari (Tetranichus Urticae e Phytoseiulus Persimilis) interagenti in alcuni ecosistemi agrari

    Energy Technology Data Exchange (ETDEWEB)

    Calvitti, M [ENEA, Centro Ricerche Casaccia, Roma (Italy). Dip. Innovazione

    1995-12-01

    This work is a brief review of the actual knowledge about biological and ecological characteristics of two species of mites: Tetranychus urticae Koch (Acarina Tetranychidae) (two-spotted spider mite) and the predaceous mite Phytoseiulus persimilis Athias Henriot (Acarina Phytoseiidae). Success obtained in biological control of spider mite, by mass release of P. persimilis, has increased the interest in biological and ecological study of these mites. Particularly, the following biological and ecological aspects of both P. persimilis and T. urticae are hereby discussed: reproductive biology; population dynamics (spider mites outbreaks) and natural regulation of the trophic interaction; feeding behaviour; biological control of two-spotted spider mite by P. persimilis. In this report experimental data obtained in laboratory have been integrated with bibliographic information concerning studies produced in natural conditions.

  6. Biological control of fruit-tree red spider mite

    NARCIS (Netherlands)

    Rabbinge, R.

    1976-01-01

    During the last decade, integrated pest control systems have been developed for several crops. One of the main fields of research in integrated control has been the control of orchard pests. Experience with modified spraying programmes in apple orchards, the increasing resistance of spider

  7. Mites and spiders act as biological control agent to sand flies

    Directory of Open Access Journals (Sweden)

    Diwakar Singh Dinesh

    2014-02-01

    Full Text Available Objective: To find out natural biological control agents of sand flies vector of kala azar in Bihar, India. Methods: Sand flies collected from the field using CDC light trap installing overnight to the collection site scrutitinized for Phlebotomus argentipes, the established vector of visceral leishmaniasis. Blood fed adult females were confined in the insectary for its development of life cycle. During developmental stages 2nd to 4th instars larvae were examined closely by using compound microscope for mite infestation. Adult spider residing along with sand flies collected in trap were kept in cage along with sand flies and their activities were watched closely and recorded by video and picture. Results: Mites were found predating 2nd to 4th instars larvae only under the laboratory conditions and lowering down the population of sand flies up to basal level within 15 d after infestation. One specific spider was found eating blood fed female sand flies kept inside the cage (n=50 attacking on lower part of thoracic region to kill the sand fly and ate desired soft part. Conclusions: Both predators, mites and spiders are acting as biological control agents to larvae and adults of sand flies respectively resulting variable density of vectors due to variable association with these predators and also cause lowering the transmission of the disease as hidden natural controlling agent of sand flies. The extensive study will be of immense help in controlling sand flies without use of environmental pollutant i.e. chemical insecticide.

  8. Suspension of Egg Hatching Caused by High Humidity and Submergence in Spider Mites.

    Science.gov (United States)

    Ubara, Masashi; Osakabe, Masahiro

    2015-08-01

    We tested the effects of high humidity and submergence on egg hatching of spider mites. In both the high humidity and submergence treatments, many Tetranychus and Panonychus eggs did not hatch until after the hatching peak of the lower humidity or unsubmerged controls. However, after humidity decreased or water was drained, many eggs hatched within 1-3 h. This was observed regardless of when high humidity or submergence treatments were implemented: either immediately after oviposition or immediately before hatching was due. Normal eyespot formation was observed in most eggs in the high humidity and submergence treatments, which indicates that spider mite embryos develop even when eggs are underwater. Therefore, delays in hatching are not caused by delayed embryonic development. A delay in hatching was always observed in Panonychus citri (McGregor) but was more variable in Tetranychus urticae Koch and Tetranychus kanzawai Kishida. The high humidity and submergence treatments affected but did not suppress larval development in these species. In contrast, many Oligonychus eggs died following the high humidity treatments. In Tetranychus and Panonychus spider mites, suspension of egg hatching may mitigate the adverse effects of rainfall. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Testing for non-target effects of spinosad on twospotted spider mites and their predator Phytoseiulus persimilis under greenhouse conditions.

    Science.gov (United States)

    Holt, Kiffnie M; Opit, George P; Nechols, James R; Margolies, David C

    2006-01-01

    The compatibility of the selective insecticide spinosad (Conserve SC), at rates recommended for thrips control in greenhouses, with release of the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) to control spider mites, was investigated in a crop of ivy geranium Pelargonium peltatum, cultivar 'Amethyst 96.' Plants were inoculated with twospotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae), 2 weeks before treatments were applied. There were three treatment variables, each at two levels: predators (released or not), spray application (water or Conserve SC at 2 ml/3.79 l), and timing of spray (1 day before or after predators were released). Twospotted spider mite populations then were sampled twice each week over a three-week period. The application or timing of spinosad had no effect on the ability of the predator to reduce the population of spider mites. Spider mite populations in the no-predator treatment continued to expand over the course of the experiment, while those in the predator-release treatment declined. We conclude that P. persimilis can be used in conjunction with spinosad on ivy geraniums without causing obvious detrimental effects to this predator or leading to a reduction in biological control.

  10. The predatory mite Phytoseiulus persimilis does not perceive odor mixtures as strictly elemental objects

    NARCIS (Netherlands)

    van Wijk, M.; de Bruijn, P.J.A.; Sabelis, M.W.

    2010-01-01

    Phytoseiulus persimilis is a predatory mite that in absence of vision relies on the detection of herbivore-induced plant odors to locate its prey, the two-spotted spider-mite Tetranychus urticae. This herbivorous prey is feeding on leaves of a wide variety of plant species in different families. The

  11. Prey Preference of the Predatory Mite, Amblyseius swirskii between First Instar Western Flower Thrips Frankliniella occidentalis and Nymphs of the Twospotted Spider Mite Tetranychus urticae

    OpenAIRE

    Xu, Xuenong; Enkegaard, Annie

    2010-01-01

    The prey preference of polyphagous predators plays an important role in suppressing different species of pest insects. In this study the prey preference of the predatory mite, Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) was examined between nymphs of the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and first instar larvae of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), as well as between active and chrysa...

  12. Functional responses and prey-stage preferences of a predatory gall midge and two predacious mites wtih twospotted spider mites, Tetranychus urticae as host

    Science.gov (United States)

    The twospotted spider mite, Tetranychus urticae (Acari: Tetranychidae), is an important pest of vegetables and other crops. This study was conducted to evaluate and compare the potential role of three commercially available predators, predatory gall midge, Feltiella acarisuga (Vallot) (Diptera: Ceci...

  13. Neonicotinoid Insecticides Alter Induced Defenses and Increase Susceptibility to Spider Mites in Distantly Related Crop Plants

    Science.gov (United States)

    Szczepaniec, Adrianna; Raupp, Michael J.; Parker, Roy D.; Kerns, David; Eubanks, Micky D.

    2013-01-01

    Background Chemical suppression of arthropod herbivores is the most common approach to plant protection. Insecticides, however, can cause unintended, adverse consequences for non-target organisms. Previous studies focused on the effects of pesticides on target and non-target pests, predatory arthropods, and concomitant ecological disruptions. Little research, however, has focused on the direct effects of insecticides on plants. Here we demonstrate that applications of neonicotinoid insecticides, one of the most important insecticide classes worldwide, suppress expression of important plant defense genes, alter levels of phytohormones involved in plant defense, and decrease plant resistance to unsusceptible herbivores, spider mites Tetranychus urticae (Acari: Tetranychidae), in multiple, distantly related crop plants. Methodology/Principal Findings Using cotton (Gossypium hirsutum), corn (Zea mays) and tomato (Solanum lycopersicum) plants, we show that transcription of phenylalanine amonia lyase, coenzyme A ligase, trypsin protease inhibitor and chitinase are suppressed and concentrations of the phytohormone OPDA and salicylic acid were altered by neonicotinoid insecticides. Consequently, the population growth of spider mites increased from 30% to over 100% on neonicotinoid-treated plants in the greenhouse and by nearly 200% in the field experiment. Conclusions/Significance Our findings are important because applications of neonicotinoid insecticides have been associated with outbreaks of spider mites in several unrelated plant species. More importantly, this is the first study to document insecticide-mediated disruption of plant defenses and link it to increased population growth of a non-target herbivore. This study adds to growing evidence that bioactive agrochemicals can have unanticipated ecological effects and suggests that the direct effects of insecticides on plant defenses should be considered when the ecological costs of insecticides are evaluated. PMID

  14. The effect of synthetic pesticides and sulfur used in conventional and organically grown strawberry and soybean on Neozygites floridana, a natural enemy of spider mites.

    Science.gov (United States)

    Castro, Thiago; Roggia, Samuel; Wekesa, Vitalis W; de Andrade Moral, Rafael; Gb Demétrio, Clarice; Delalibera, Italo; Klingen, Ingeborg

    2016-09-01

    The beneficial fungus Neozygites floridana kills the two-spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda-cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. The insecticides/ acaricides abamectin and lambda-cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  15. Comparison of cultivars of ornamental crop Gerbera jamesonii on production of spider mite-induced volatiles, and their attractiveness to the predator Phytoseiulus persimilis.

    Science.gov (United States)

    Krips, O E; Willems, P E; Gols, R; Posthumus, M A; Gort, G; Dicke, M

    2001-07-01

    We investigated whether volatiles produced by spider mite-damaged plants of four gerbera cultivars differ in attractiveness to Phytoseiulus persimilis, a specialist predator of spider mites, and how the mite-induced odor blends differ in chemical composition. The gerbera cultivars differed in resistance, as expressed in terms of spider mite intrinsic rate of population increase (rm). In order of increasing resistance these were Sirtaki, Rondena, Fame, and Bianca. To correct for differences in damage inflicted on the cultivars, we developed a method to compare the attractiveness of the blends, based on the assumption that a larger amount of spider mite damage leads to higher attraction of P persimilis. Spider mite-induced volatiles of cultivars Rondena and Bianca were preferred over those of cultivar Sirtaki. Spider mite-induced volatiles of cultivars Sirtaki and Fame did not differ in attractiveness to P. persimilis. Sirtaki plants had a lower relative production of terpenes than the other three cultivars. This was attributed to a low production of cis-alpha-bergamotene, trans-alpha-bergamotene, trans-beta-bergamotene, and (E)-beta-farnesene. The emission of (E)-beta-ocimene and linalool was lower in Sirtaki and Fame leaves than in Bianca and Rondena. The importance of these chemical differences in the differential attraction of predatory mites is discussed.

  16. Reproductive performance of seven strains of the tomato red spider mite Tetranychus evansi (Acari: Tetranychidae) at five temperatures

    DEFF Research Database (Denmark)

    Gotoh, T.; Sugimoto, N.; Pallini, A.

    2010-01-01

    The tomato red spider mite Tetranychus evansi Baker et Pritchard occurs on solanaceous plants, and causes serious damage to a variety of crops in Africa and Europe. In 2001 this species was also found in Japan, on nightshade (Solanum nigrum L.), and its invasion to solanaceous of agricultural imp...

  17. First divergence time estimate of spiders, scorpions, mites and ticks (subphylum: Chelicerata) inferred from mitochondrial phylogeny.

    Science.gov (United States)

    Jeyaprakash, Ayyamperumal; Hoy, Marjorie A

    2009-01-01

    Spiders, scorpions, mites and ticks (chelicerates) form one of the most diverse groups of arthropods on land, but their origin and times of diversification are not yet established. We estimated, for the first time, the molecular divergence times for these chelicerates using complete mitochondrial sequences from 25 taxa. All mitochondrial genes were evaluated individually or after concatenation. Sequences belonging to three missing genes (ND3, 6, and tRNA-Asp) from three taxa, as well as the faster-evolving ribosomal RNAs (12S and 16S), tRNAs, and the third base of each codon from 11 protein-coding genes (PCGs) (COI-III, CYTB, ATP8, 6, ND1-2, 4L, and 4-5), were identified and removed. The remaining concatenated sequences from 11 PCGs produced a completely resolved phylogenetic tree and confirmed that all chelicerates are monophyletic. Removing the third base from each codon was essential to resolve the phylogeny, which allowed deep divergence times to be calculated using three nodes calibrated with upper and lower priors. Our estimates indicate that the orders and classes of spiders, scorpions, mites, and ticks diversified in the late Paleozoic, much earlier than previously reported from fossil date estimates. The divergence time estimated for ticks suggests that their first land hosts could have been amphibians rather than reptiles. Using molecular data, we separated the spider-scorpion clades and estimated their divergence times at 397 +/- 23 million years ago. Algae, fungi, plants, and animals, including insects, were well established on land when these chelicerates diversified. Future analyses, involving mitochondrial sequences from additional chelicerate taxa and the inclusion of nuclear genes (or entire genomes) will provide a more complete picture of the evolution of the Chelicerata, the second most abundant group of animals on earth.

  18. Effects of powdery mildew fungicide programs on twospotted spider mite (Acari: Tetranychidae), hop aphid (Hemiptera: Aphididae), and their natural enemies in hop yards.

    Science.gov (United States)

    Gent, D H; James, D G; Wright, L C; Brooks, D J; Barbour, J D; Dreves, A J; Fisher, G C; Walton, V M

    2009-02-01

    Twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), and hop aphid, Phorodon humuli (Schrank) (Hemiptera: Aphididae), are the most important arthropod pests of hop (Humulus lupulus L.) in the Northern Hemisphere. A potential barrier for greater adoption of conservation biological control strategies for spider mites and hop aphid is the extensive use of fungicides for management of hop powdery mildew, Podosphaera macularis (Wallr.:Fr.) U. Braun & S. Takamatsu. Field studies conducted in experimental plots in Oregon and Washington in 2005 and 2006 quantified the effects of powdery mildew fungicide programs (i.e., sulfur, paraffinic oil, and synthetic fungicides) on arthropod pests and natural enemies on hop. Fungicide treatment significantly affected spider mite populations in all four studies. Multiple applications of sulfur fungicides applied before burr development resulted in 1.4-3.3-fold greater spider mite populations during summer. Near the cessation of the sulfur applications, or after a lag of 20-30 d, spider mite populations increased significantly faster on sulfur treated plants compared with water-treated plants in three of four experiments. The effect of paraffinic oil on spider mites was varied, leading to exacerbation of spider mites in Oregon and Washington in 2005, suppression of mites in Oregon in 2006, and no significant effect compared with water in Washington in 2006. Significant relative treatment effects for cone damage due to spider mite feeding were detected in Oregon in 2005 in plots treated with sulfur and paraffinic oil compared with water and synthetic fungicides. Mean populations of hop aphids were similar among treatments in Oregon, although sulfur treatment suppressed hop aphid populations in Washington in 2005 and 2006. Populations of individual predacious insect species and cumulative abundance of macropredators were not consistently suppressed or stimulated by treatments in all trials. However, predatory mite

  19. Spatiotemporal heterogeneity of tomato induced defense responses affects spider mite performance and behavior.

    Science.gov (United States)

    Schimmel, Bernardus C J; Ataide, Livia M S; Kant, Merijn R

    2017-10-03

    When feeding from tomato (Solanum lycopersicum), the generalist spider mite Tetranychus urticae induces jasmonate (JA)- and salicylate (SA)-regulated defense responses that hamper its performance. The related T. evansi, a Solanaceae-specialist, suppresses these defenses, thereby upholding a high performance. On a shared leaf, T. urticae can be facilitated by T. evansi, likely via suppression of defenses by the latter. Yet, when infesting the same plant, T. evansi outcompetes T. urticae. Recently, we found that T. evansi intensifies suppression of defenses locally, i.e., at its feeding site, after T. urticae mites were introduced onto adjacent leaf tissue. This hyper-suppression is paralleled by an increased oviposition rate of T. evansi, probably promoting its competitive population growth. Here we present additional data that not only provide insight into the spatiotemporal dynamics of defense induction and suppression by mites, but that also suggest T. evansi to manipulate more than JA and SA defenses alone.

  20. Neonicotinoid Insecticide Imidacloprid Causes Outbreaks of Spider Mites on Elm Trees in Urban Landscapes

    Science.gov (United States)

    Szczepaniec, Adrianna; Creary, Scott F.; Laskowski, Kate L.; Nyrop, Jan P.; Raupp, Michael J.

    2011-01-01

    Background Attempts to eradicate alien arthropods often require pesticide applications. An effort to remove an alien beetle from Central Park in New York City, USA, resulted in widespread treatments of trees with the neonicotinoid insecticide imidacloprid. Imidacloprid's systemic activity and mode of entry via roots or trunk injections reduce risk of environmental contamination and limit exposure of non-target organisms to pesticide residues. However, unexpected outbreaks of a formerly innocuous herbivore, Tetranychus schoenei (Acari: Tetranychidae), followed imidacloprid applications to elms in Central Park. This undesirable outcome necessitated an assessment of imidacloprid's impact on communities of arthropods, its effects on predators, and enhancement of the performance of T. schoenei. Methodology/Principal Findings By sampling arthropods in elm canopies over three years in two locations, we document changes in the structure of communities following applications of imidacloprid. Differences in community structure were mostly attributable to increases in the abundance of T. schoenei on elms treated with imidacloprid. In laboratory experiments, predators of T. schoenei were poisoned through ingestion of prey exposed to imidacloprid. Imidacloprid's proclivity to elevate fecundity of T. schoenei also contributed to their elevated densities on treated elms. Conclusions/Significance This is the first study to report the effects of pesticide applications on the arthropod communities in urban landscapes and demonstrate that imidacloprid increases spider mite fecundity through a plant-mediated mechanism. Laboratory experiments provide evidence that imidacloprid debilitates insect predators of spider mites suggesting that relaxation of top-down regulation combined with enhanced reproduction promoted a non-target herbivore to pest status. With global commerce accelerating the incidence of arthropod invasions, prophylactic applications of pesticides play a major role in

  1. Effect of acaricidal components isolated from lettuce (Lactuca sativa) on carmine spider mite (Tetranychus cinnabarinus Boisd.).

    Science.gov (United States)

    Li, M; Zhang, Y; Ding, W; Luo, J; Li, S; Zhang, Q

    2018-06-01

    This study aimed to evaluate the acaricidal activity of lettuce (Lactuca sativa) extracts against carmine spider mites (Tetranychus cinnabarinus Boisd.) and isolate the acaricidal components. Acaricidal activities of lettuce extracts isolated from different parts (the leaf, root and seed) using various solvents (petroleum ether, acetone and methanol) were evaluated with slide-dip bioassay and relatively high median lethal concentration (LC50) values were detected. Acetone extracts of lettuce leaves harvested in July and September were fractionated and isolated with silica gel and thin-layer chromatography. Consequently, acetone extracts of lettuce leaves harvested in July exhibited higher acaricidal activity than those harvested in September, with an LC50 value of 0.268 mg ml-1 at 72 h post-treatment. A total of 27 fractions were obtained from the acetone extract of lettuce leaves harvested in July, and mite mortalities with the 11th and 12th fractions were higher than those with the other 25 fractions (LC50: 0.751 and 1.258 mg ml-1 at 48 h post-treatment, respectively). Subsequently, active acaricidal components of the 11th fraction were identified by infrared, nuclear magnetic resonance and liquid chromatography/mass spectrometry. Five components were isolated from the 11th fraction, with components 11-a and 11-b showing relatively high acaricidal activities (LC50: 0.288 and 0.114 mg ml-1 at 48 h post-treatment, respectively). Component 11-a was identified as β-sitosterol. In conclusion, acetone extracts of lettuce leaves harvested in July might be used as a novel phytogenic acaricide to control mites.

  2. The preliminary assessment and isolation of entomopathogenic fungi to be used in biological control with twospotted spider mite [Tetranychus urticae (acari, tetranychidae)] from East Anatolia

    Science.gov (United States)

    Örtücü, Serkan; Algur, Ömer Faruk

    2017-04-01

    This study was conducted to isolation entomopathogenic fungi for possible use in biocontrol of two-spotted spider mite Tetranychus urticae Koch. and to determine their pathogenicity. For this purpose, plant leaves infected with T. urticae were collected from Erzurum, Kars and Ardahan. At laboratory, the internal and external mycoflora of T.urticae individuals on plant leaves were determined. As a result of isolation, twenty-five different fungi species belonging to the genera Acremonium, Alternaria, Aspergillus, Beauveria, Cladosporium, Gliocladium, Humicola, Penicillium, Trichoderma, Isaria, Ulocladium and Verticillium were obtained. Pathogenicity of this forty-five isolate belonging to twenty-five species were evaluated. As a test organism, T. urticae was used and suspensions (1 × 108conidia ml-1) were prepared in Tween 80. 2ml suspension of a single dose was sprayed onto down side of bean leaf discs using hand sprayer. Mortality was recorded daily for 7 days. A total of twelve isolates belonging to three species were determined to be pathogen against T.urticae. According to scale used: AT020 Isaria farinosa and AT025 Cladosporium cladosporioides were determined as least pathogen, AT037 and AT101 Beauveria bassiana, and AT019 and AT026 C. cladosporioides, and AT035 and AT036 I. farinosa as moderate pathogen, AT007, AT021, AT034 and AT076 B. bassiana as highly pathogen. The other thirty-three isolates found that not pathogenic against T.urticae.

  3. The residual and direct effects of reduced-risk and conventional miticides on twospotted spider mites, Tetranychus urticae (Acari: Tetranychidae) and predatory mites (Acari: Phytoseiidae)

    International Nuclear Information System (INIS)

    Liburd, O.E.; White, J.C.; Rhodes, E.M.; Browdy, A.A.

    2007-01-01

    The residual effects of several reduced-risk and conventional miticides were evaluated in strawberries (Fragaria × ananassa Duchesne) on the twospotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) and on 2 predatory mites, Neoseiulus californicus McGregor and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). Experiments were conducted in the laboratory and greenhouse. The greenhouse experiments also tested the direct effects of the miticides on TSSM. The efficacy of conventional and reduced-risk miticides was evaluated on strawberry leaf discs and on whole plants for control of TSSM. Furthermore, the residual effects of these miticides were evaluated on whole strawberry plants against selective predatory mites. For TSSM, 5 treatments were evaluated: a conventional miticide; fenbutatin-oxide (Vendex[reg]) and 3 reduced-risk miticides; binfenazate (Acramite 50WP[reg]), activated garlic extract (Repel[reg]), sesame seed and castor oil (Wipeout[reg]), and a water-treated control. For predatory mites, the residual effects of only Acramite[reg] and Vendex[reg] were evaluated. Acramite[reg] was the most effective acaricide in reducing TSSM populations in both the laboratory and greenhouse experiments. Vendex[reg] and Wipeout[reg] were also effective in the laboratory, but did not cause significant reduction of TSSM in the greenhouse. Repel[reg] was the least effective of the 4 pesticides evaluated. Neither Acramite[reg] nor Vendex[reg] had a significant effect on either predatory mite species. However, there appeared to be more predatory mites on the Vendex[reg]-treated plants than on the Acramite[reg]-treated plants. There were significantly more predatory mites of both species on the cue plants, which were inoculated with TSSM versus the non-cue plants, which were not inoculated. (author) [es

  4. A burst of ABC genes in the genome of the polyphagous spider mite Tetranychus urticae.

    Science.gov (United States)

    Dermauw, Wannes; Osborne, Edward John; Clark, Richard M; Grbić, Miodrag; Tirry, Luc; Van Leeuwen, Thomas

    2013-05-10

    The ABC (ATP-binding cassette) gene superfamily is widespread across all living species. The majority of ABC genes encode ABC transporters, which are membrane-spanning proteins capable of transferring substrates across biological membranes by hydrolyzing ATP. Although ABC transporters have often been associated with resistance to drugs and toxic compounds, within the Arthropoda ABC gene families have only been characterized in detail in several insects and a crustacean. In this study, we report a genome-wide survey and expression analysis of the ABC gene superfamily in the spider mite, Tetranychus urticae, a chelicerate ~ 450 million years diverged from other Arthropod lineages. T. urticae is a major agricultural pest, and is among of the most polyphagous arthropod herbivores known. The species resists a staggering array of toxic plant secondary metabolites, and has developed resistance to all major classes of pesticides in use for its control. We identified 103 ABC genes in the T. urticae genome, the highest number discovered in a metazoan species to date. Within the T. urticae ABC gene set, all members of the eight currently described subfamilies (A to H) were detected. A phylogenetic analysis revealed that the high number of ABC genes in T. urticae is due primarily to lineage-specific expansions of ABC genes within the ABCC, ABCG and ABCH subfamilies. In particular, the ABCC subfamily harbors the highest number of T. urticae ABC genes (39). In a comparative genomic analysis, we found clear orthologous relationships between a subset of T. urticae ABC proteins and ABC proteins in both vertebrates and invertebrates known to be involved in fundamental cellular processes. These included members of the ABCB-half transporters, and the ABCD, ABCE and ABCF families. Furthermore, one-to-one orthologues could be distinguished between T. urticae proteins and human ABCC10, ABCG5 and ABCG8, the Drosophila melanogaster sulfonylurea receptor and ecdysone-regulated transporter E

  5. Variation in nesting behavior of eight species of spider mites, Stigmaeopsis having sociality

    Science.gov (United States)

    Saito, Yutaka; Zhang, Yan-Xuan; Mori, Kotaro; Ito, Katsura; Sato, Yukie; Chittenden, Anthony R.; Lin, Jian-Zhen; Chae, Younghae; Sakagami, Takane; Sahara, Ken

    2016-10-01

    Nesting behavior is considered to be an important element of social living in animals. The spider mites belonging to the genus Stigmaeopsis spend their lives within nests produced from silk threads. Several of these species show cooperative sociality, while the others are subsocial. In order to identify the origins of this social behavior, comparisons of nest sizes, nesting behaviors (making nests continuously or separately), and their associated traits (fecal deposition patterns) were made for eight cogeneric Stigmaeopsis species showing various levels of social development. All of these species inhabit bamboo plants (Poaceae). We initially addressed the proximate factor of nest size variation. The variation in nest size of the eight species corresponded well with the variation in dorsal seta sc1 length, suggesting that nest size variation among species may have a genetic basis. The time spent within a nest (nest duration) increased with nest size on the respective host plants. Nest arrangement patterns varied among species showing different sized nests: Large nest builders continuously extended their nests, while middle and small nest-building species built new separate nests, which resulted in different social interaction times among species, and is thought to be closely related to social development. Fecal deposition behaviors also varied among Stigmaeopsis species, suggesting diversity in anti-predatory adaptations. Finally, we discuss how the variation in sociality observed within this genus is likely the result of nest size variation that initially evolved as anti-predator strategies.

  6. Genetic variation in jasmonic acid- and spider mite-induced plant volatile emission of cucumber accessions and attraction of the predator Phytoseiulus persimilis.

    Science.gov (United States)

    Kappers, Iris F; Verstappen, Francel W A; Luckerhoff, Ludo L P; Bouwmeester, Harro J; Dicke, Marcel

    2010-05-01

    Cucumber plants (Cucumis sativus L.) respond to spider-mite (Tetranychus urticae) damage with the release of specific volatiles that are exploited by predatory mites, the natural enemies of the spider mites, to locate their prey. The production of volatiles also can be induced by exposing plants to the plant hormone jasmonic acid. We analyzed volatile emissions from 15 cucumber accessions upon herbivory by spider mites and upon exposure to jasmonic acid using gas chromatography-mass spectrometry. Upon induction, cucumber plants emitted over 24 different compounds, and the blend of induced volatiles consisted predominantly of terpenoids. The total amount of volatiles was higher in plants treated with jasmonic acid than in those infested with spider mites, with (E)-4,8-dimethyl-1,3,7-nonatriene, (E,E)-alpha-farnesene, and (E)-beta-ocimene as the most abundant compounds in all accessions in both treatments. Significant variation among the accessions was found for the 24 major volatile compounds. The accessions differed strongly in total amount of volatiles emitted, and displayed very different odor profiles. Principal component analysis performed on the relative quantities of particular compounds within the blend revealed clusters of highly correlated volatiles, which is suggestive of common metabolic pathways. A number of cucumber accessions also were tested for their attractiveness to Phytoseiulus persimilis, a specialist predator of spider mites. Differences in the attraction of predatory mites by the various accessions correlated to differences in the individual chemical profiles of these accessions. The presence of genetic variation in induced plant volatile emission in cucumber shows that it is possible to breed for cucumber varieties that are more attractive to predatory mites and other biological control agents.

  7. Geography has a greater effect than Wolbachia infection on population genetic structure in the spider mite, Tetranychus pueraricola.

    Science.gov (United States)

    Chen, Y-T; Zhang, Y-K; Du, W-X; Jin, P-Y; Hong, X-Y

    2016-10-01

    Wolbachia is an intracellular symbiotic bacterium that infects various spider mite species and is associated with alterations in host reproduction, which indicates the potential role in mite evolution. However, studies of Wolbachia infections in the spider mite Tetranychus pueraricola, a major agricultural pest, are limited. Here, we used multilocus sequence typing to determine Wolbachia infection status and examined the relationship between Wolbachia infection status and mitochondrial diversity in T. pueraricola from 12 populations in China. The prevalence of Wolbachia ranged from 2.8 to 50%, and three strains (wTpue1, wTpue2, and wTpue3) were identified. We also found double infections (wTpue1 + wTpue3) within the same individuals. Furthermore, the wTpue1 strain caused weak cytoplasmic incompatibility (CI) (egg hatchability ~55%), whereas another widespread strain, wTpue3, did not induce CI. There was no reduction in mitochondrial DNA (mtDNA) or nuclear DNA diversity among infected individuals, and mtDNA haplotypes did not correspond to specific Wolbachia strains. Phylogenetic analysis and analysis of molecular variance revealed that the distribution of mtDNA and nuclear DNA haplotypes were significantly associated with geography. These findings indicate that Wolbachia infection in T. pueraricola is complex, but T. pueraricola genetic differentiation likely resulted from substantial geographic isolation.

  8. Egg hatching response to a range of ultraviolet-B (UV-B) radiation doses for four predatory mites and the herbivorous spider mite Tetranychus urticae.

    Science.gov (United States)

    Koveos, Dimitrios S; Suzuki, Takeshi; Terzidou, Anastasia; Kokkari, Anastasia; Floros, George; Damos, Petros; Kouloussis, Nikos A

    2017-01-01

    Egg hatchability of four predatory mites-Phytoseiulus persimilis Athias-Henriot, Iphiseius [Amblyseius] degenerans Berlese, Amblyseius swirskii Athias-Henriot, and Euseius finlandicus Oudemans (Acari: Phytoseiidae)-and the spider mite Tetranychus urticae Koch (Acari: Tetranychidae) was determined under various UV-B doses either in constant darkness (DD) or with simultaneous irradiation using white light. Under UV-B irradiation and DD or simultaneous irradiation with white light, the predator's eggs hatched in significantly lower percentages than in the control non-exposed eggs, which indicates deleterious effects of UV-B on embryonic development. In addition, higher hatchability percentages were observed under UV-B irradiation and DD in eggs of the predatory mites than in eggs of T. urticae. This might be caused by a higher involvement of an antioxidant system, shield effects by pigments or a mere shorter duration of embryonic development in predatory mites than in T. urticae, thus avoiding accumulative effects of UV-B. Although no eggs of T. urticae hatched under UV-B irradiation and DD, variable hatchability percentages were observed under simultaneous irradiation with white light, which suggests the involvement of a photoreactivation system that reduces UV-B damages. Under the same doses with simultaneous irradiation with white light, eggs of T. urticae displayed higher photoreactivation and were more tolerant to UV-B than eggs of the predatory mites. Among predators variation regarding the tolerance to UV-B effects was observed, with eggs of P. persimilis and I. degenerans being more tolerant to UV-B radiation than eggs of A. swirskii and E. finlandicus.

  9. Jasmonic Acid Is a Key Regulator of Spider Mite-Induced Volatile Terpenoid and Methyl Salicylate Emission in Tomato1[w

    Science.gov (United States)

    Ament, Kai; Kant, Merijn R.; Sabelis, Maurice W.; Haring, Michel A.; Schuurink, Robert C.

    2004-01-01

    The tomato (Lycopersicon esculentum) mutant def-1, which is deficient in induced jasmonic acid (JA) accumulation upon wounding or herbivory, was used to study the role of JA in the direct and indirect defense responses to phytophagous mites (Tetranychus urticae). In contrast to earlier reports, spider mites laid as many eggs and caused as much damage on def-1 as on wild-type plants, even though def-1 lacked induction of proteinase inhibitor activity. However, the hatching-rate of eggs on def-1 was significantly higher, suggesting that JA-dependent direct defenses enhanced egg mortality or increased the time needed for embryonic development. As to gene expression, def-1 had lower levels of JA-related transcripts but higher levels of salicylic acid (SA) related transcripts after 1 d of spider mite infestation. Furthermore, the indirect defense response was absent in def-1, since the five typical spider mite-induced tomato-volatiles (methyl salicylate [MeSA], 4,8,12-trimethyltrideca-1,3,7,11-tetraene [TMTT], linalool, trans-nerolidol, and trans-β-ocimene) were not induced and the predatory mite Phytoseiulus persimilis did not discriminate between infested and uninfested def-1 tomatoes as it did with wild-type tomatoes. Similarly, the expression of the MeSA biosynthetic gene salicylic acid methyltransferase (SAMT) was induced by spider mites in wild type but not in def-1. Exogenous application of JA to def-1 induced the accumulation of SAMT and putative geranylgeranyl diphosphate synthase transcripts and restored MeSA- and TMTT-emission upon herbivory. JA is therefore necessary to induce the enzymatic conversion of SA into MeSA. We conclude that JA is essential for establishing the spider mite-induced indirect defense response in tomato. PMID:15310835

  10. New developments in insecticide resistance in the glasshouse whitefly (Trialeurodes vaporariorum) and the two-spotted spider mite (Tetranychus urticae) in the UK.

    Science.gov (United States)

    Gorman, Kevin; Hewitt, Fiona; Denholm, Ian; Devine, Gregor J

    2002-02-01

    A recent survey of insecticide resistance in two of the most problematic pests in UK glasshouses revealed some new developments. At least some individuals in all UK samples of Trialeurodes vaporariorum that were tested resisted the insect growth regulator (IGR) buprofezin. The most strongly resistant strains were unaffected by the field application rate of this compound, and even samples from populations that had never been exposed to buprofezin contained individuals that survived the highest concentration applied (10,000 mg litre-1). The field rate of buprofezin was shown to select for resistance through vapour action alone. The benzophenylurea teflubenzuron, an unrelated IGR, was cross-resisted by buprofezin-resistant individuals. There was no evidence of resistance to imidacloprid, but all T vaporariorum strains tested, regardless of origin, exhibited a high innate tolerance to nicotine, when compared with another whitefly species, Bemisia tabaci. Marked resistance to fenbutatin oxide and tebufenpyrad was found in single glasshouse populations of Tetranychus urticae, but these compounds and abamectin appeared to remain highly effective against all other strains collected.

  11. Effects of Nitrogen Fertilization on Potato Leafhopper (Hemiptera: Cicadellidae) and Maple Spider Mite (Acari: Tetranychidae) on Nursery-Grown Maples.

    Science.gov (United States)

    Prado, Julia; Quesada, Carlos; Gosney, Michael; Mickelbart, Michael V; Sadof, Clifford

    2015-06-01

    Although leaf nitrogen (N) has been shown to increase the suitability of hosts to herbivorous arthropods, the responses of these pests to N fertilization on susceptible and resistant host plants are not well characterized. This study determined how different rates of N fertilization affected injury caused by the potato leafhopper (Empoasca fabae Harris) and the abundance of maple spider mite (Oligonychus aceris (Shimer)) on 'Red Sunset' red maple (Acer rubrum) and 'Autumn Blaze' Freeman maple (Acer×freemanii) during two years in Indiana. N fertilization increased leaf N concentration in both maple cultivars, albeit to a lesser extent during the second year of the study. Overall, Red Sunset maples were more susceptible to E. fabae injury than Autumn Blaze, whereas Autumn Blaze maples supported higher populations of O. aceris. Differences in populations of O. aceris were attributed to differences between communities of stigmaeid and phytoseiid mites on each cultivar. Injury caused by E. fabae increased with N fertilization in a dose-dependent manner in both cultivars. Although N fertilization increased the abundance of O. aceris on both maple cultivars, there was no difference between the 20 and 40 g rates. We suggest the capacity of N fertilization to increase O. aceris on maples could be limited at higher trophic levels by the community of predatory mites. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Inoculate Release of Stethorus gilvifrons Mulsan (Coleoptera: Coccinellidae for Biological Control of Date Palm Spider Mite, Oligonychus afrasiaticusMcGregor (Prostigmata: Tetranychidae

    Directory of Open Access Journals (Sweden)

    M. Latifian

    2017-12-01

    Full Text Available Introduction: The spider mite, Oligonychus afrasiaticus feeds by sucking the sap from the immature fruits tissue. The natural color of fruits changes to pale yellow or gray by mite's feeding. Damaged fruit are cracked and its damage can dry out the fruits. Because of resistance to pesticides, resurgence of date palm spider mite causes to disrupt the natural balance of their population. Tiny black ladybird beetle, Stethorous gilvifrons is the most important and active lady beetle species in Khuzestan province and is very effective on biological control of the spider mite. Determination of the amount and release time of the lady beetles are the most important factors in the implementation of biological control programs of date palm spider mite. So, careful monitoring, time of the release and the ability of deployment of predatory ladybird are essential steps to success in the programs of biological control. Materials and Methods: This research was conducted in Shadegan region of Khuzestan province. The nested design was used to compare the efficiency of different inoculate release methods of the predator, S. gilvifrons. The main niches include three release times which were at the time of emergence, three days and one week after emergence of date palm spider mite in date palm plantation. Sub nesting including three different levels of predator release including minimum, moderate and maximum release with 0.5, 1 and 3 predator /m2 per day and were continued for two weeks. The two or three-days ladybirds were used to release. First, the infected clusters were covered by mesh fabric and ladybirds were released under them. After a week, mantles were opened up to the establishment of ladybird run on the normal condition of date palm plantations. This experiment was repeated three times, and each replication consists of a quarter- hectare plantation with dominant cultivar Sayer.Three date Palm trees from each release and control were randomly selected

  13. Spider mite (Acari: Tetranychidae) mitochondrial COI phylogeny reviewed: host plant relationships, phylogeography, reproductive parasites and barcoding

    NARCIS (Netherlands)

    Ros, V.I.D.; Breeuwer, J.A.J.

    2007-01-01

    The past 15 years have witnessed a number of molecular studies that aimed to resolve issues of species delineation and phylogeny of mites in the family Tetranychidae. The central part of the mitochondrial COI region has frequently been used for investigating intra- and interspecific variation. All

  14. Effect of aqueous plant extracts on tea red spider mite, Oligonychus ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-02-04

    Feb 4, 2009 ... integrated mite management. Key words: Tea ... Scientific name. Family. Parts used .... C.V.%. 8.64. Mean of five observations (30 eggs/observation). 100 numbers of ..... This work is part of a Tea Research Association in-house project ... innovation in tea science and sustainable development in tea. Industry ...

  15. How do Neoseiulus californicus (Acari: Phytoseiidae) females penetrate densely webbed spider mite nests?

    Science.gov (United States)

    Montserrat, M; de la Peña, F; Hormaza, J I; González-Fernández, J J

    2008-02-01

    The persea mite Oligonychus perseae is a pest of avocado trees that builds extremely dense webbed nests that protect them against natural enemies, including phytoseiid mites. Nests have one or two marginal entrances that are small and flattened. The predatory mite Neoseiulus californicus co-occurs with O. perseae in the avocado orchards of the south-east of Spain. Penetration inside nests through the entrances by this predator is thought to be hindered by its size and its globular-shaped body. However, in the field it has repeatedly been found inside nests that were clearly ripped. Perhaps penetration of the nests has been facilitated by nest wall ripping caused by some other species or by unfavourable abiotic factors. However, to assess whether N. californicus is also able to enter the nest of O. perseae by itself, we carried out laboratory experiments and made a short film. They show how this predator manages to overcome the webbed wall, and that it can penetrate and forage inside nests of O. perseae.

  16. Selection of entomopathogenic fungi against the red spider mite Tetranychus kanzawai (Kishida (Tetranychidae: Acarina

    Directory of Open Access Journals (Sweden)

    Yayan Sanjaya

    2013-12-01

    Full Text Available The pathogenicity of three entomopathogenic fungal species to Tetranychus kanzawai was investigated. Seven isolates of Metarhizium anisopliae, six isolates of Beauveria bassiana, and an isolate of Paecilomyces lilacinus from the Philippines and Indonesia were evaluated. The following studies were undertaken: (1 screening of M. anisoplae, B. bassiana and P. lilicanus pathogenic to T. kanzawai, and (2 bioefficacy studies of the selected entomopathogenic fungi under greenhouse conditions. Conidia of each isolate were mass-produced on potato dextrose agar (PDA at 26+-1 oC and a 12-hour photophase for a maximum of 21 days. Preliminary screening for the most pathogenic isolate within the same species was determined using suspension with 104 to 108 conidia ml-1. At 4 days after treatment (DAT, the pathogenicity within M. anisopliae isolates in decreasing order was Ma5>Ma6>Ma4>Ma2>Ma1>Ma3>Ma7 while for B. bassiana, was Bb6>Bb5>Bb4>Bb3>Bb1>Bb2. The top three most pathogenic isolates within the two species were subjected to further studies to determine the most virulent isolate against T. kanzawai. At 5 DAT, the LC50 values of M. anisopliae isolates ranged from 5.0 x102 to 1.4x103 while for B. bassiana ranged from 1.2 x 103 to 2.4x 103 conidia ml-1. Based on LC50, the virulence of the fungal isolates within the species in decreasing order was Ma6>Ma5>Ma4 and Bb6>Bb5>Bb4. However, the LC50 values are not significantly different from each other. Green house trials showed that the epizootic of entomopathogenic fungus can regulate the population of mites. The fungal isolates used in the study, although not originally isolated from mites were virulent to T. kanzawai, indicating their wide host range.

  17. Joint Effect of Solar UVB and Heat Stress on the Seasonal Change of Egg Hatching Success in the Herbivorous False Spider Mite (Acari: Tenuipalpidae).

    Science.gov (United States)

    Sudo, M; Osakabe, M

    2015-12-01

    Seasonal population dynamics of an herbivorous mite has been documented in terms of the relationship between thermoresponses and temporal biological factors such as resource availability or predation risk. Although recent studies emphasize the deleterious effects of solar ultraviolet-B (UVB; 280-320 nm wavelengths) radiation on plant-dwelling mites, how UVB affects mite population remains largely unknown. On a wild shrub Viburnum erosum var. punctatum in Kyoto, an herbivorous false spider mite, Brevipalpus obovatus Donnadieu, occurs only in autumn. Females of this species lay one-third of their eggs on upper leaf surfaces. Oviposition on upper surfaces is beneficial for avoiding predation by phytoseiids, but exposes eggs to solar UVB and heat stress. To test the hypothesis that the seasonal occurrence of this mite is determined by interactions between solar UVB radiation and temperature, we examined variation in egg hatching success under near-ambient and UV-attenuated sunlight conditions from spring to autumn. The UV-attenuation significantly improved hatching success. However, most eggs died under heat stress regardless of UV treatments in July and August. We established a deterministic heat stress-cumulative UVB dose-egg hatching success response model, which we applied to meteorological data. The model analyses illustrated lower and higher survivability peaks in late May and October, respectively, which partly corresponded to data for annual field occurrence, indicating the importance of solar UVB radiation and heat stress as determinants of the seasonal occurrence of this mite. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. An analysis of radiation-induced damage in the spider mite. Relationship between mortality of haploid and diploid eggs in two successive generations

    International Nuclear Information System (INIS)

    Leenhouts, H.P.; Chadwick, K.H.

    1976-01-01

    Unfertilized females of the spider mite (Tetranychus urticae) produce only haploid eggs which develop into a haploid male. Fertilized females produce both haploid eggs (unfertilized), which develop into males, and diploid eggs (fertilized), which develop into females. Radiobiological experiments performed by A.M. Feldmann (Association Euratom-ITAL) made data available on the radiation-induced mortality of haploid and diploid eggs in the F 1 and F 2 generation following irradiation of either males or females with X rays or fast neutrons. The data have been analysed using the molecular theory of cell survival where it is assumed that DNA double strand breaks, induced randomly in the cell, are the critical radiation-induced lesions, which lead to cell death. Theoretical relationships are derived for the dose dependence of hatchability in haploid and diploid eggs in the first and second generations expressed as a function of the radiation damage in the parental genome. These theoretical relationships can be used to derive the inter-relationship between the different hatchabilities, and the results from the spider mite have been analysed using these considerations. It is concluded that the radiation-induced genetic damage arises from one type of initial lesion. The eventual radiobiological implications of this analysis are discussed, expecially with respect to the transmittance of radiation-induced genetic damage after low-level radiation. (author)

  19. Analysis of insecticide resistance-related genes of the Carmine spider mite Tetranychus cinnabarinus based on a de novo assembled transcriptome.

    Science.gov (United States)

    Xu, Zhifeng; Zhu, Wenyi; Liu, Yanchao; Liu, Xing; Chen, Qiushuang; Peng, Miao; Wang, Xiangzun; Shen, Guangmao; He, Lin

    2014-01-01

    The carmine spider mite (CSM), Tetranychus cinnabarinus, is an important pest mite in agriculture, because it can develop insecticide resistance easily. To gain valuable gene information and molecular basis for the future insecticide resistance study of CSM, the first transcriptome analysis of CSM was conducted. A total of 45,016 contigs and 25,519 unigenes were generated from the de novo transcriptome assembly, and 15,167 unigenes were annotated via BLAST querying against current databases, including nr, SwissProt, the Clusters of Orthologous Groups (COGs), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). Aligning the transcript to Tetranychus urticae genome, the 19255 (75.45%) of the transcripts had significant (e-value insecticide resistance in arthropod were generated from CSM transcriptome, including 53 P450-, 22 GSTs-, 23 CarEs-, 1 AChE-, 7 GluCls-, 9 nAChRs-, 8 GABA receptor-, 1 sodium channel-, 6 ATPase- and 12 Cyt b genes. We developed significant molecular resources for T. cinnabarinus putatively involved in insecticide resistance. The transcriptome assembly analysis will significantly facilitate our study on the mechanism of adapting environmental stress (including insecticide) in CSM at the molecular level, and will be very important for developing new control strategies against this pest mite.

  20. Single versus multiple enemies and the impact on biological control of spider mites in cassava fields in West-Africa

    NARCIS (Netherlands)

    Onzo, A.; Sabelis, M.W.; Hanna, R.

    2014-01-01

    To determine whether to use single or multiple predator species for biological pest control requires manipulative field experiments. We performed such tests in Benin (West Africa) in cassava fields infested by the cassava green mite Mononychellus tanajoa, and the cotton red mite Oligonychus

  1. Enhancement of the reproductive potential of Mallada boninensis Okamoto (Neuroptera: Chrysopidae, a predator of red spider mite infesting tea: An evaluation of artificial diets

    Directory of Open Access Journals (Sweden)

    Vasanthakumar Duraikkannu

    2012-01-01

    Full Text Available Green lacewing Mallada boninensis is an important predator of various soft-bodied arthropods, including red spider mites in tea. Efforts were made to develop mass rearing technology for this predator in a cost effective manner. Three combinations of artificial diets (Protinex (AD1, egg yolk (AD2 and royal jelly (AD3 based were evaluated in comparison with standard diet (Protinex + Honey. All the tested diets influenced the egg-laying capacity of M. boninensis. The egg yolk-based diet resulted in more egg production than the other two diets. Survival of all life stages of M. boninensis was also observed on each diet and no significant difference was noticed. Results revealed that the egg yolk-based diet is the best of the three diet combinations tested in view of high fecundity and survival rate of M. boninensis.

  2. ``Sleeping with the enemy''—predator-induced diapause in a mite

    Science.gov (United States)

    Kroon, Annemarie; Veenendaal, René L.; Bruin, Jan; Egas, Martijn; Sabelis, Maurice W.

    2008-12-01

    Diapause in arthropods is a physiological state of dormancy that is generally thought to promote survival during harsh seasons and dispersal, but it may also serve to avoid predation in space and time. Here, we show that predation-related odours induce diapause in female adult spider mites. We argue that this response allows them to move into an area where they are free of enemies, yet forced to survive without food. Spider mites are specialised leaf feeders, but—in late summer—they experience severe predation on leaves. Hence, they face a dilemma: to stay on the leaf and risk being eaten or to move away from the leaf and risk death from starvation and thirst. Female two-spotted spider mites solve this dilemma by dramatically changing their physiology when exposed to predation-associated cues. This allows them to disperse away from leaves and to survive in winter refuges in the bark of trees or in the soil. We conclude that the mere presence of predation-associated cues causes some herbivorous mites to seek refuge, thereby retarding the growth rate of the population as a whole: a trait-mediated indirect effect that may have consequences for the stability of predator prey systems and for ecosystem structure.

  3. The predatory mite Phytoseiulus persimilis adjusts patch-leaving to own and progeny prey needs.

    Science.gov (United States)

    Vanas, V; Enigl, M; Walzer, A; Schausberger, P

    2006-01-01

    Integration of optimal foraging and optimal oviposition theories suggests that predator females should adjust patch leaving to own and progeny prey needs to maximize current and future reproductive success. We tested this hypothesis in the predatory mite Phytoseiulus persimilis and its patchily distributed prey, the two-spotted spider mite Tetranychus urticae. In three separate experiments we assessed (1) the minimum number of prey needed to complete juvenile development, (2) the minimum number of prey needed to produce an egg, and (3) the ratio between eggs laid and spider mites left when a gravid P. persimilis female leaves a patch. Experiments (1) and (2) were the pre-requirements to assess the fitness costs associated with staying or leaving a prey patch. Immature P. persimilis needed at least 7 and on average 14+/-3.6 (SD) T. urticae eggs to reach adulthood. Gravid females needed at least 5 and on average 8.5+/-3.1 (SD) T. urticae eggs to produce an egg. Most females left the initial patch before spider mite extinction, leaving prey for progeny to develop to adulthood. Females placed in a low density patch left 5.6+/-6.1 (SD) eggs per egg laid, whereas those placed in a high density patch left 15.8+/-13.7 (SD) eggs per egg laid. The three experiments in concert suggest that gravid P. persimilis females are able to balance the trade off between optimal foraging and optimal oviposition and adjust patch-leaving to own and progeny prey needs.

  4. The effect of genetically enriched (E)-β-ocimene and the role of floral scent in the attraction of the predatory mite Phytoseiulus persimilis to spider mite-induced volatile blends of torenia.

    Science.gov (United States)

    Shimoda, Takeshi; Nishihara, Masahiro; Ozawa, Rika; Takabayashi, Junji; Arimura, Gen-ichiro

    2012-03-01

    Plants under herbivore attack emit mixtures of volatiles (herbivore-induced plant volatiles, HIPVs) that can attract predators of the herbivores. Although the composition of HIPVs should be critical for the attraction, most studies of transgenic plant-emitted volatiles have simply addressed the effect of trans-volatiles without embedding in other endogenous plant volatiles. We investigated the abilities of transgenic wishbone flower plants (Torenia hybrida and Torenia fournieri) infested with spider mites, emitting a trans-volatile ((E)-β-ocimene) in the presence or absence of endogenous volatiles (natural HIPVs and/or floral volatiles), to attract predatory mites (Phytoseiulus persimilis). In both olfactory- and glasshouse-based assays, P. persimilis females were attracted to natural HIPVs from infested wildtype (wt) plants of T. hybrida but not to those of T. fournieri. The trans-volatile enhanced the ability to attract P. persimilis only when added to an active HIPV blend from the infested transgenic T. hybrida plants, in comparison with the attraction by infested wt plants. Intriguingly, floral volatiles abolished the enhanced attractive ability of T. hybrida transformants, although floral volatiles themselves did not elicit any attraction or avoidance behavior. Predator responses to trans-volatiles were found to depend on various background volatiles (e.g. natural HIPVs and floral volatiles) endogenously emitted by the transgenic plants. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  5. Comparison of single and combination treatments of Phytoseiulus persimilis, Neoseiulus californicus, and Acramite (bifenazate) for control of twospotted spider mites in strawberries.

    Science.gov (United States)

    Rhodes, Elena M; Liburd, Oscar E; Kelts, Crystal; Rondon, Silvia I; Francis, Roger R

    2006-01-01

    Greenhouse and field experiments were conducted from 2003 to 2005 to determine the effectiveness of combining releases of two predatory mite species, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), and a reduced-risk miticide, Acramite (bifenazate), for control of twospotted spider mite (TSSM) (Tetranychus urticae Koch) in strawberries. In the greenhouse experiment, a combination treatment of P. persimilis and N. californicus was compared with single treatments of each species, Acramite application, and untreated control. All treatments significantly reduced TSSM numbers compared with the control. Field studies employed two approaches: one investigating the same five treatments as the greenhouse experiment and a second, comparing combination treatments of P. persimilis/N. californicus, Acramite/N. californicus, and Acramite/P. persimilis to single treatments of each and to control plots. Among the combination treatments, the P. persimilis/N. californicus treatment significantly reduced TSSM numbers compared with the control, but was not as effective as N. californicus alone during the 2003-2004 field season. Also, combination treatments of Acramite/N. californicus, and Acramite/P. persimilis significantly reduced TSSM populations compared with the control. These findings indicate that all three combination treatments are promising options for TSSM control in strawberries for growers in northern Florida and other strawberry producing areas of the world.

  6. Morphology of the olfactory system in the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    van Wijk, Michiel; Wadman, Wytse J; Sabelis, Maurice W

    2006-01-01

    The predatory mite Phytoseiulus persimilis locates its prey, the two-spotted spider mite, by means of herbivore-induced plant volatiles. The olfactory response to this quantitatively and qualitatively variable source of information is particularly well documented. The mites perform this task with a peripheral olfactory system that consists of just five putative olfactory sensilla that reside in a dorsal field at the tip of their first pair of legs. The receptor cells innervate a glomerular olfactory lobe just ventral of the first pedal ganglion. We have made a 3D reconstruction of the caudal half of the olfactory lobe in adult females. The glomerular organization as well as the glomerular innervation appears conserved across different individuals. The adult females have, by approximation, a 1:1 ratio of olfactory receptor cells to olfactory glomeruli.

  7. Analysis of insecticide resistance-related genes of the Carmine spider mite Tetranychus cinnabarinus based on a de novo assembled transcriptome.

    Directory of Open Access Journals (Sweden)

    Zhifeng Xu

    Full Text Available The carmine spider mite (CSM, Tetranychus cinnabarinus, is an important pest mite in agriculture, because it can develop insecticide resistance easily. To gain valuable gene information and molecular basis for the future insecticide resistance study of CSM, the first transcriptome analysis of CSM was conducted. A total of 45,016 contigs and 25,519 unigenes were generated from the de novo transcriptome assembly, and 15,167 unigenes were annotated via BLAST querying against current databases, including nr, SwissProt, the Clusters of Orthologous Groups (COGs, Kyoto Encyclopedia of Genes and Genomes (KEGG and Gene Ontology (GO. Aligning the transcript to Tetranychus urticae genome, the 19255 (75.45% of the transcripts had significant (e-value <10-5 matches to T. urticae DNA genome, 19111 sequences matched to T. urticae proteome with an average protein length coverage of 42.55%. Core Eukaryotic Genes Mapping Approach (CEGMA analysis identified 435 core eukaryotic genes (CEGs in the CSM dataset corresponding to 95% coverage. Ten gene categories that relate to insecticide resistance in arthropod were generated from CSM transcriptome, including 53 P450-, 22 GSTs-, 23 CarEs-, 1 AChE-, 7 GluCls-, 9 nAChRs-, 8 GABA receptor-, 1 sodium channel-, 6 ATPase- and 12 Cyt b genes. We developed significant molecular resources for T. cinnabarinus putatively involved in insecticide resistance. The transcriptome assembly analysis will significantly facilitate our study on the mechanism of adapting environmental stress (including insecticide in CSM at the molecular level, and will be very important for developing new control strategies against this pest mite.

  8. Intraguild interactions between the predatory mites Neoseiulus californicus and Phytoseiulus persimilis.

    Science.gov (United States)

    Cakmak, Ibrahim; Janssen, Arne; Sabelis, Maurice W

    2006-01-01

    Species at the same trophic level may interact through competition for food, but can also interact through intraguild predation. Intraguild predation is widespread at the second and third trophic level and the effects may cascade down to the plant level. The effects of intraguild predation can be modified by antipredator behaviour in the intraguild prey. We studied intraguild predation and antipredator behaviour in two species of predatory mite, Neoseiulus californicus and Phytoseiulus persimilis, which are both used for control of the two-spotted spider mite in greenhouse and outdoor crops. Using a Y-tube olfactometer, we assessed in particular whether each of the two predators avoids odours emanating from prey patches occupied by the heterospecific predator. Furthermore, we measured the occurrence and rate of intraguild predation of different developmental stages of P. persimilis and N. californicus on bean leaves in absence or in presence of the shared prey. Neither of the two predator species avoided prey patches with the heterospecific competitor, both when inexperienced with the other predator and when experienced with prey patches occupied by the heterospecific predator. Intraguild experiments showed that N. californicus is a potential intraguild predator of P. persimilis. However, P. persimilis did not suffer much from intraguild predation as long as the shared prey was present. This is probably because N. californicus prefers to feed on two-spotted spider mites rather than on its intraguild prey.

  9. The interaction of two-spotted spider mites, Tetranychus urticae Koch, with Cry protein production and predation by Amblyseius andersoni (Chant) in Cry1Ac/Cry2Ab cotton and Cry1F maize.

    Science.gov (United States)

    Crops producing insecticidal crystal (Cry) proteins from the bacterium, Bacillus thuringiensis (Bt), are an important tool for managing lepidopteran pests on cotton and maize. However, the effects of these Bt crops on non-target organisms, especially natural enemies that provide biological control s...

  10. Jasmonic acid is a key regulator of spider mite-induced volatile terpenoid and methyl salicylate emission in tomato

    NARCIS (Netherlands)

    Ament, K.; Kant, M.R.; Sabelis, M.W.; Haring, M.A.; Schuurink, R.C.

    2004-01-01

    The tomato (Lycopersicon esculentum) mutant def-1, which is deficient in induced jasmonic acid (JA) accumulation upon wounding or herbivory, was used to study the role of JA in the direct and indirect defense responses to phytophagous mites (Tetranychus urticae). In contrast to earlier reports,

  11. Sex-specific developmental plasticity of generalist and specialist predatory mites (Acari: Phytoseiidae) in response to food stress.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2011-03-01

    We studied developmental plasticity under food stress in three female-biased size dimorphic predatory mite species, Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius andersoni. All three species prey on two-spotted spider mites but differ in the degree of adaptation to this prey. Phytoseiulus persimilis is a specialized spider mite predator, N. californicus is a generalist with a preference for spider mites, and A. andersoni is a broad generalist. Immature predators were offered prey patches of varying density and their survival chances, dispersal tendencies, age and size at maturity measured. Amblyseius andersoni dispersed earlier from and had lower survival chances in low density prey patches than N. californicus and P. persimilis. Age at maturity was not affected by prey density in the generalist A. andersoni, whereas both the specialist P. persimilis and the generalist N. californicus accelerated development at low prey densities. Species-specific plasticity in age at maturity reflects opposite survival strategies when confronted with limited prey: to prematurely leave and search for other food (A. andersoni) or to stay and accelerate development (P. persimilis, N. californicus). In all species, size at maturity was more plastic in females than males, indicating that males incur higher fitness costs from deviations from optimal body size.

  12. Patterns of reproductive isolation in a haplodiploid - strong post-mating, prezygotic barriers among three forms of a social spider mite.

    Science.gov (United States)

    Sato, Yukie; Sakamoto, Hironori; Gotoh, Tetsuo; Saito, Yutaka; Chao, Jung-Tai; Egas, Martijn; Mochizuki, Atsushi

    2018-03-22

    In speciation research, much attention is paid to the evolution of reproductive barriers, preventing diverging groups from hybridizing back into one gene pool. The prevalent view is that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection and genetic drift in groups that are segregated spatially and/or temporally. Reproductive barriers, however, can also be reinforced by natural selection against maladaptive hybridization. These mutually compatible theories are both empirically supported by studies, analysing relationships between intensity of reproductive isolation and genetic distance in sympatric taxa and allopatric taxa. Here, we present the - to our knowledge - first comparative study in a haplodiploid organism, the social spider mite Stigmaeopsis miscanthi, by measuring premating and post-mating, pre- and post-zygotic components of reproductive isolation, using three recently diverged forms of the mite that partly overlap in home range. We carried out cross-experiments and measured genetic distances (mitochondrial DNA and nuclear DNA) among parapatric and allopatric populations of the three forms. Our results show that the three forms are reproductively isolated, despite the absence of premating barriers, and that the post-mating, prezygotic component contributes most to reproductive isolation. As expected, the strength of post-mating reproductive barriers positively correlated with genetic distance. We did not find a clear pattern of prezygotic barriers evolving faster in parapatry than in allopatry, although one form did show a trend in line with the ecological and behavioural relationships between the forms. Our study advocates the versatility of haplodiploid animals for investigating the evolution of reproductive barriers. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

  13. Ricoseius loxocheles (Acari: Phytoseiidae) is not a predator of false spider mite on coffee crops: What does it eat?

    Science.gov (United States)

    Vacacela Ajila, Henry E; Ferreira, João A M; Colares, Felipe; Oliveira, Cleber M; Bernardo, Ana Maria G; Venzon, Madelaine; Pallini, Angelo

    2018-01-01

    Ricoseius loxocheles (De Leon) (Acari: Phytoseiidae) is often found in coffee crops and is known to feed on coffee leaf rust, Hemileia vastatrix Berkeley and Broome (Uredinales). As the occurrence of coffee leaf rust is limited primarily to the rainy season, the mite may use other food sources to survive during the periods of low pathogen prevalence. It is well known that phytoseiid mites can survive on a variety of food sources, such as herbivorous mites, fungi and pollen. We evaluated the ability of R. loxocheles to survive and reproduce on a diet of Brevipalpus phoenicis Geijskes (Acari: Tenuipalpidae), cattail pollen (Typha spp.), clover rust (Puccinia oxalidis), bee pollen (Santa Bárbara ® dehydrated pollen, Santa Bárbara, MG, Brazil) and coffee leaf rust. Ricoseius loxocheles did not survive or reproduce on any B. phoenicis stages tested (egg, larva, adult). The survival and oviposition of R. loxocheles were directly affected by the presence of coffee rust urediniospores, but not by the presence of the prey. Survival and oviposition of the phytoseiid were similar when fed cattail pollen, clover rust and coffee leaf rust but was lower when fed bee pollen. Our results show that R. loxocheles is not a predator of B. phoenicis but it is able to utilize other resources besides coffee leaf rust.

  14. A Gene Family Coding for Salivary Proteins (SHOT) of the Polyphagous Spider Mite Tetranychus urticae Exhibits Fast Host-Dependent Transcriptional Plasticity.

    Science.gov (United States)

    Jonckheere, Wim; Dermauw, Wannes; Khalighi, Mousaalreza; Pavlidi, Nena; Reubens, Wim; Baggerman, Geert; Tirry, Luc; Menschaert, Gerben; Kant, Merijn R; Vanholme, Bartel; Van Leeuwen, Thomas

    2018-01-01

    The salivary protein repertoire released by the herbivorous pest Tetranychus urticae is assumed to hold keys to its success on diverse crops. We report on a spider mite-specific protein family that is expanded in T. urticae. The encoding genes have an expression pattern restricted to the anterior podocephalic glands, while peptide fragments were found in the T. urticae secretome, supporting the salivary nature of these proteins. As peptide fragments were identified in a host-dependent manner, we designated this family as the SHOT (secreted host-responsive protein of Tetranychidae) family. The proteins were divided in three groups based on sequence similarity. Unlike TuSHOT3 genes, TuSHOT1 and TuSHOT2 genes were highly expressed when feeding on a subset of family Fabaceae, while expression was depleted on other hosts. TuSHOT1 and TuSHOT2 expression was induced within 24 h after certain host transfers, pointing toward transcriptional plasticity rather than selection as the cause. Transfer from an 'inducer' to a 'noninducer' plant was associated with slow yet strong downregulation of TuSHOT1 and TuSHOT2, occurring over generations rather than hours. This asymmetric on and off regulation points toward host-specific effects of SHOT proteins, which is further supported by the diversity of SHOT genes identified in Tetranychidae with a distinct host repertoire.

  15. Comparing chemical and biological control strategies for twospotted spider mites (Acari: Tetranychidae) in commercial greenhouse production of bedding plants.

    Science.gov (United States)

    Opit, George P; Perret, Jamis; Holt, Kiffnie; Nechols, James R; Margolies, David C; Williams, Kimberly A

    2009-02-01

    Efficacy, costs, and impact on crop salability of various biological and chemical control strategies for Tetranychus urticae Koch (Acari: Tetranychidae) were evaluated on mixed plantings of impatiens, Impatiens wallerana Hook.f (Ericales: Balsaminaceae), and ivy geranium, Pelargonium peltatum (1.) L'Hér. Ex Aiton (Geraniales: Geraniaceae), cultivars in commercial greenhouses. Chemical control consisting of the miticide bifenazate (Floramite) was compared with two biological control strategies using the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). Treatments were 1) a single, early application of bifenazate; 2) a single, early release of predatory mites at a 1:4 predator:pest ratio based on leaf samples to estimate pest density; 3) a weekly release of predatory mites at numbers based on the area covered by the crop; and 4) an untreated control. T. urticae populations were monitored for 3 wk after the earliest treatment. When plants were ready for market, their salability was estimated. Bifenazate and density-based P. persimilis treatments effectively reduced T. urticae numbers starting 1 wk after plants had been treated, whereas the scheduled, area-based P. persimilis treatment had little or no effect. The percentage of flats that could be sold at the highest market wholesale price ranged from 15 to 33%, 44 to 86%, 84 to 95%, and 92 to 100%, in the control, weekly area-based P. persimilis, bifenazate, and single density-based P. persimilis treatments, respectively. We have shown that in commercial greenhouse production of herbaceous ornamental bedding plants, estimating pest density to determine the appropriate number of predators to release is as effective and offers nearly the same economic benefit as prophylactic use of pesticides.

  16. State-dependent and odour-mediated anemotactic responses of the predatory mite Phytoseiulus persimilis in a wind tunnel.

    Science.gov (United States)

    Van Tilborg, Merijn; Sabelis, Maurice W; Roessingh, Peter

    2004-01-01

    Anemotaxis in the predatory mite Phytoseiulus persimilis (both well-fed and starved), has previously been studied on a wire grid under slight turbulent airflow conditions yielding weak, yet distinct, gradients in wind speed and odour concentration (Sabelis and Van der Weel 1993). Such conditions might have critically influenced the outcome of the study. We repeated these experiments, under laminar airflow conditions on a flat surface in a wind tunnel, thereby avoiding variation in wind speed and odour concentration. Treatments for starved and well-fed mites were (1) still-air without herbivore-induced plant volatiles (HIPV) (well-fed mites only), (2) an HIPV-free air stream, and (3) an air stream with HIPV (originating from Lima bean plants infested by two-spotted spider mites, Tetranychus urticae). Well-fed mites oriented in random directions in still-air without HIPV. In an air stream, starved mites always oriented upwind, whether plant odours were present or not. Well-fed mites oriented downwind in an HIPV-free air stream, but in random directions in an air stream with HIPV. Only under the last treatment our results differed from those of Sabelis and Van der Weel (1993).

  17. The predatory mite Phytoseiulus persimilis does not perceive odor mixtures as strictly elemental objects.

    Science.gov (United States)

    van Wijk, Michiel; de Bruijn, Paulien J A; Sabelis, Maurice W

    2010-11-01

    Phytoseiulus persimilis is a predatory mite that in absence of vision relies on the detection of herbivore-induced plant odors to locate its prey, the two-spotted spider-mite Tetranychus urticae. This herbivorous prey is feeding on leaves of a wide variety of plant species in different families. The predatory mites respond to numerous structurally different compounds. However, typical spider-mite induced plant compounds do not attract more predatory mites than plant compounds not associated with prey. Because the mites are sensitive to many compounds, components of odor mixtures may affect each other's perception. Although the response to pure compounds has been well documented, little is known how interactions among compounds affect the response to odor mixtures. We assessed the relation between the mites' responses elicited by simple mixtures of two compounds and by the single components of these mixtures. The preference for the mixture was compared to predictions under three conceptual models, each based on one of the following assumptions: (1) the responses elicited by each of the individual components can be added to each other; (2) they can be averaged; or (3) one response overshadows the other. The observed response differed significantly from the response predicted under the additive response, average response, and overshadowing response model in 52, 36, and 32% of the experimental tests, respectively. Moreover, the behavioral responses elicited by individual compounds and their binary mixtures were determined as a function of the odor concentration. The relative contribution of each component to the behavioral response elicited by the mixture varied with the odor concentration, even though the ratio of both compounds in the mixture was kept constant. Our experiments revealed that compounds that elicited no response had an effect on the response elicited by binary mixtures that they were part of. The results are not consistent with the hypothesis that P

  18. Transcriptome Analysis of the Carmine Spider Mite, Tetranychus cinnabarinus (Boisduval, 1867 (Acari: Tetranychidae, and Its Response to β-Sitosterol

    Directory of Open Access Journals (Sweden)

    Chunya Bu

    2015-01-01

    Full Text Available Tetranychus cinnabarinus (Acari: Tetranychidae is a worldwide polyphagous agricultural pest that has the title of resistance champion among arthropods. We reported previously the identification of the acaricidal compound β-sitosterol from Mentha piperita and Inula japonica. However, the acaricidal mechanism of β-sitosterol is unclear. Due to the limited genetic research carried out, we de novo assembled the transcriptome of T. cinnabarinus using Illumina sequencing and conducted a differential expression analysis of control and β-sitosterol-treated mites. In total, we obtained >5.4 G high-quality bases for each sample with unprecedented sequencing depth and assembled them into 22,941 unigenes. We identified 617 xenobiotic metabolism-related genes involved in detoxification, binding, and transporting of xenobiotics. A highly expanded xenobiotic metabolic system was found in mites. T. cinnabarinus detoxification genes—including carboxyl/cholinesterase and ABC transporter class C—were upregulated after β-sitosterol treatment. Defense-related proteins, such as Toll-like receptor, legumain, and serine proteases, were also activated. Furthermore, other important genes—such as the chloride channel protein, cytochrome b, carboxypeptidase, peritrophic membrane chitin binding protein, and calphostin—may also play important roles in mites’ response to β-sitosterol. Our results demonstrate that high-throughput-omics tool facilitates identification of xenobiotic metabolism-related genes and illustration of the acaricidal mechanisms of β-sitosterol.

  19. Higher glandular trichome density in tomato leaflets and repellence to spider mites Alta densidade de tricomas glandulares em tomateiro e aumento da repelência a ácaros rajados

    Directory of Open Access Journals (Sweden)

    Wilson Roberto Maluf

    2007-09-01

    Full Text Available The objective of this work was to evaluate the feasibility of selection for higher glandular trichome densities, as an indirect criterion of selection for increasing repellence to spider mites Tetranychus urticae, in tomato populations derived from an interspecific cross between Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Trichome densities were evaluated in 19 genotypes, including 12 from advanced backcross populations, derived from the original cross L. esculentum x L. hirsutum var. glabratum PI 134417. Counts were made both on the adaxial and abaxial leaf surfaces, and trichomes were classified into glandular types IV and VI, other glandular types (types I+VII, and nonglandular types. Mite repellence was measured by distances walked by mites onto the tomato leaf surface after 20, 40 and 60 min. Spider mite repellence biotests indicated that higher densities of glandular trichomes (especially type VI decreased the distances walked by the mites onto the tomato leaf surface. Selection of plants with higher densities of glandular trichomes can be an efficient criterion to obtain tomato genotypes with higher resistance (repellence to spider mites.O objetivo deste trabalho foi avaliar a eficiência da seleção para maior densidade de tricomas glandulares na resistência (repelência ao ácaro Tetranychus urticae, em populações de tomate derivadas do cruzamento interespecífico Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Foram avaliados 19 genótipos quanto à densidade de tricomas, que incluíram 12 derivados de populações avançadas de retrocruzamentos, obtidos a partir do cruzamento original L. esculentum x L. hirsutum var. glabratum PI 134417. Nas faces abaxial e adaxial dos folíolos, realizaram-se as contagens e os tricomas foram classificados em glandulares tipo IV e VI, outros glandulares (tipo I e VII e não glandulares. A repelência aos ácaros foi medida pela distância média, percorrida pelo

  20. Comparison of thermal activity thresholds of the spider mite predators Phytoseiulus macropilis and Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Coombs, Megan R; Bale, Jeffrey S

    2013-04-01

    The lower and upper thermal activity thresholds of the predatory mite Phytoseiulus macropilis Banks (Acari: Phytoseiidae) were compared with those of its prey Tetranychus urticae Koch (Acari: Tetranychidae) and one of the alternative commercially available control agents for T. urticae, Phytoseiulus persimilis Athias-Henriot. Adult female P. macropilis retained ambulatory function (CTmin) and movement of appendages (chill coma) at significantly lower temperatures (8.2 and 0.4 °C, respectively) than that of P. persimilis (11.1 and 3.3 °C) and T. urticae (10.6 and 10.3 °C). As the temperature was raised, P. macropilis ceased walking (CTmax) and entered heat coma (42.7 and 43.6 °C), beyond the upper locomotory limits of P. persimilis (40.0 and 41.1 °C), but before T. urticae (47.3 and 48.7 °C). Walking speeds were investigated and P. persimilis was found to have significantly faster ambulation than P. macropilis and T. urticae across a range of temperatures. The lower thermal activity threshold data indicate that P. macropilis will make an effective biological control agent in temperate climates.

  1. Effects of electron beam irradiation on cut flowers and mites

    International Nuclear Information System (INIS)

    Dohino, Toshiyuki; Tanabe, Kazuo

    1994-01-01

    Two spotted spider mite, Tetranychus urticae KOCH were irradiated with electron beams (2.5MeV) to develop an alternative quarantine treatment for imported cut flowers. The tolerance of eggs increased with age (1-5-day-old). Immature stages (larva-teleiochrysalis) irradiated at 0.4-0.8kGy increased tolerance with their development. Mated mature females irradiated at 0.4kGy or higher did not produce viable eggs, although temporary recovery was observed at 0.2kGy. Adult males were sterilized at 0.4kGy because non-irradiated virgin females mated with yielded female progeny malformed and sterilized. Various effects of electron beam irradiation were observed when nine species of cut flowers were irradiated in 5MeV Dynamitron accelerator. Chrysanthemum and rose were most sensitive among cut flowers. (author)

  2. Spatial distribution of phytophagous mites (Aca ri: Tetranychidae) on strawberry plants

    International Nuclear Information System (INIS)

    Fadini, Marcos A.M.; Venzon, Madelaine; Oliveira, Hamilton G.; Pallini, Angelo; Vilela, Evaldo F.

    2007-01-01

    Many phytophagous mites can attack strawberry plants, Fragaria x ananassa, among them the southern red mite, Oligonychus ilicis McGregor, and the two-spotted spider mite, Tetranychus urticae Koch. They are found together feeding on the same plant on the upper and underside of the leaves, respectively. Here we studied the choice for feeding sites of O. ilicis and T. urticae on strawberry plants. The first hypothesis tested whether the feeding site choice would be related to the fitness of the species. The second hypothesis dealt whether the feeding site would be determined by the presence of a heterospecific mite. We evaluated the preference, biology and reproductive success of O. ilicis and T. urticae on the under and upper side surface of strawberry leaves infested or not by the heterospecific. O. ilicis preferred to stay on the upper side surface while T. urticae preferred the underside. The preference for the leaf surface correlated with the reproductive success of the species (measured by the intrinsic growth rate). The choice pattern of feeding sites did not alter when the choice test was applied using sites previously infested by heterospecific. Although O. ilicis and T. urticae, apparently, do not interact directly for feeding sites, there is a chance that the first species induces defenses in strawberry plant enabling to reduce the fitness of the second species. The possibility of those species stay together on strawberry plant increases the damage capacity to the culture. (author)

  3. Gamma irradiation as a quarantine treatment of apples infested with diapausing eggs of the European red spider mite, Panonychus ulmi (Koch) (Acarina: Tetranychidae)

    International Nuclear Information System (INIS)

    Ignatowicz, S.

    1997-01-01

    Viable eggs of the European red mite, Panonychus ulmi (Koch), on apples have been the concern of several importing countries and exports require preshipment, phytosanitary treatment to reduce or eliminate live eggs. Because fumigation is often detrimental to the commodity appearance and shelf-life, resulting in a loss of commercial value, there is a need for alternatives for chemical pest control as a quarantine treatment, and irradiation could be a new strategy method. The data obtained indicate that a dose of gamma radiation equal to or higher than 0.15 kGy seems to be adequate to prevent post-diapause hatching of wintering eggs of the European red mite. Thus, this dose is suggested for quarantine treatment of apples infested with wintering eggs of the European red mite. (author)

  4. A Modular Cage System Design for Continuous Medium to Large Scale In Vivo Rearing of Predatory Mites (Acari: Phytoseiidae

    Directory of Open Access Journals (Sweden)

    Juan Alfredo Morales-Ramos

    2014-01-01

    Full Text Available A new stackable modular system was developed for continuous in vivo production of phytoseiid mites. The system consists of cage units that are filled with lima beans,  Phaseolus lunatus, or red beans, P. vulgaris, leaves infested with high levels of the two-spotted spider mites, Tetranychus urticae. The cage units connect with each other through a connection cup, which also serves for monitoring and collection. Predatory mites migrate upwards to new cage units as prey is depleted. The system was evaluated for production of Phytoseiulus persimilis. During a 6-month experimental period, 20,894.9±10,482.5 (mean ± standard deviation predators were produced per week. The production consisted of 4.1±4.6% nymphs and 95.9±4.6% adults. A mean of 554.5±59.8 predatory mites were collected per harvested cage and the mean interval length between harvests was 6.57±6.76 days. The potential for commercial and experimental applications is discussed.

  5. Susceptibility of geographically isolated populations of the Tomato red spider mite (Tetranychus evansi Baker & Pritchard to commonly used acaricides on tomato crops in Kenya

    Directory of Open Access Journals (Sweden)

    F. J. Toroitich

    2014-04-01

    Full Text Available Farmers in Kenya continue to raise concerns of difficulty in managing Tetranychus evansi, the most widespread pest species of tomato applying the most commonly used acaricides. This invasive pest species is not only found in Kenya, but in Eastern and Southern Africa, as well as parts of Europe and Asia. In the current study, populations of T. evansi were collected from farms in the four major tomato-growing areas of Kenya (Loitoktok, Kibwezi, Athi-River and Subukia and their susceptibility compared to a laboratory culture (ICIPE that had been maintained for three years without exposure to acaricides. Susceptibility of T. evansi eggs and adults (contact and residual to Brigade (bifenthrin, Dimethoate (dimethoate, Karate (lambdacyhalothrin, Kelthane (dicofol, Omite (propargite and Polytrin (profenofos+ cypermethrin was tested in the laboratory using respective manufacturer’s recommended concentrations. Dimethoate resulted in variable ovicidal mortality while Kelthane, Brigade, Karate, Omite and Polytrin had high mortality across all populations. Similarly, adult contact and residual mortality was lower than that of the other chemicals when exposed to Dimethoate regardless of the location. Furthermore, it also had no residual effect on the mites from ICIPE and Kibwezi. On the other hand, Kelthane was most lethal against the mites from all locations followed by Brigade and Polytrin in that order. Omite caused significantly lower mortality on mites from Subukia while Karate produced variable effects on mites from Kibwezi, Loitoktok and Subukia. The implications of these findings are further discussed.

  6. Social familiarity governs prey patch-exploitation, -leaving and inter-patch distribution of the group-living predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Zach, Gernot J; Peneder, Stefan; Strodl, Markus A; Schausberger, Peter

    2012-01-01

    In group-living animals, social interactions and their effects on other life activities such as foraging are commonly determined by discrimination among group members. Accordingly, many group-living species evolved sophisticated social recognition abilities such as the ability to recognize familiar individuals, i.e. individuals encountered before. Social familiarity may affect within-group interactions and between-group movements. In environments with patchily distributed prey, group-living predators must repeatedly decide whether to stay with the group in a given prey patch or to leave and search for new prey patches and groups. Based on the assumption that in group-living animals social familiarity allows to optimize the performance in other tasks, as for example predicted by limited attention theory, we assessed the influence of social familiarity on prey patch exploitation, patch-leaving, and inter-patch distribution of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. P. persimilis is highly specialized on herbivorous spider mite prey such as the two-spotted spider mite Tetranychus urticae, which is patchily distributed on its host plants. We conducted two experiments with (1) groups of juvenile P. persimilis under limited food on interconnected detached leaflets, and (2) groups of adult P. persimilis females under limited food on whole plants. Familiar individuals of both juvenile and adult predator groups were more exploratory and dispersed earlier from a given spider mite patch, occupied more leaves and depleted prey more quickly than individuals of unfamiliar groups. Moreover, familiar juvenile predators had higher survival chances than unfamiliar juveniles. We argue that patch-exploitation and -leaving, and inter-patch dispersion were more favorably coordinated in groups of familiar than unfamiliar predators, alleviating intraspecific competition and improving prey utilization and suppression.

  7. Social familiarity governs prey patch-exploitation, -leaving and inter-patch distribution of the group-living predatory mite Phytoseiulus persimilis.

    Directory of Open Access Journals (Sweden)

    Gernot J Zach

    Full Text Available In group-living animals, social interactions and their effects on other life activities such as foraging are commonly determined by discrimination among group members. Accordingly, many group-living species evolved sophisticated social recognition abilities such as the ability to recognize familiar individuals, i.e. individuals encountered before. Social familiarity may affect within-group interactions and between-group movements. In environments with patchily distributed prey, group-living predators must repeatedly decide whether to stay with the group in a given prey patch or to leave and search for new prey patches and groups.Based on the assumption that in group-living animals social familiarity allows to optimize the performance in other tasks, as for example predicted by limited attention theory, we assessed the influence of social familiarity on prey patch exploitation, patch-leaving, and inter-patch distribution of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. P. persimilis is highly specialized on herbivorous spider mite prey such as the two-spotted spider mite Tetranychus urticae, which is patchily distributed on its host plants. We conducted two experiments with (1 groups of juvenile P. persimilis under limited food on interconnected detached leaflets, and (2 groups of adult P. persimilis females under limited food on whole plants. Familiar individuals of both juvenile and adult predator groups were more exploratory and dispersed earlier from a given spider mite patch, occupied more leaves and depleted prey more quickly than individuals of unfamiliar groups. Moreover, familiar juvenile predators had higher survival chances than unfamiliar juveniles.We argue that patch-exploitation and -leaving, and inter-patch dispersion were more favorably coordinated in groups of familiar than unfamiliar predators, alleviating intraspecific competition and improving prey utilization and suppression.

  8. Influence of long-term exposure to simulated acid rain on development, reproduction and acaricide susceptibility of the carmine spider mite, Tetranychus cinnabarinus

    Science.gov (United States)

    Wang, Jin-Jun; Zhang, Jian-Ping; He, Lin; Zhao, Zhi-Mo

    2006-01-01

    Development, reproduction and acaricide susceptibility of Tetranychus cinnabarinus (Boisduvals) (Acari: Tetranychidae) were investigated after long-term (about 40 generations) exposure to various levels of acid rain; pH 2.5, 3.0, 4.0, and 5.6. Deionized water (pH 6.8) served as a control. The mites were reared on eggplant leaves at 28°C, 80%RH and a photoperiod of 14:10 (L:D) in the laboratory. The results showed that the duration of the immature stage was significantly affected by acid rain exposure. The shortest duration (8.90 days) was recorded for populations exposed to pH 5.6 acid rain, while the longest duration (9.37 days) occurred after exposure to pH 2.5 acid rain. Compared with the control population, adult longevity was shortened with an increase in acidity. Similarly, the oviposition duration was also shortened by an increase in acidity. Statistically, female fecundity did not differ significantly between pH 5.6, pH 4.0 and control populations, but did differ significantly between the control population and those exposed to pH 2.5 and pH 3.0 acid rain. This suggested that the mite suffered reproductive defects after long-term exposure to acid rain with higher acidity (pH 2.5 and 3.0). The intrinsic rate of increase among different populations was not significantly affected, but the net reproductive rate of populations exposed to pH 2.5 and 3.0 acid rain was significantly less than pH4.0, 5.6, and control populations. Bioassay results showed that after long-term exposure to acid rain, susceptibility of the mites to two acaricides, dichlorvos and fenpropathrin, did not change significantly. PMID:19537978

  9. Influence of long-term exposure to simulated acid rain on development, reproduction and acaricide susceptibility of the carmine spider mite, Tetranychus cinnabarinus

    OpenAIRE

    Wang, Jin-Jun; Zhang, Jian-Ping; He, Lin; Zhao, Zhi-Mo

    2006-01-01

    Development, reproduction and acaricide susceptibility of Tetranychus cinnabarinus (Boisduvals) (Acari: Tetranychidae) were investigated after long-term (about 40 generations) exposure to various levels of acid rain; pH 2.5, 3.0, 4.0, and 5.6. Deionized water (pH 6.8) served as a control. The mites were reared on eggplant leaves at 28?C, 80%RH and a photoperiod of 14:10 (L:D) in the laboratory. The results showed that the duration of the immature stage was significantly affected by acid rain ...

  10. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites

    NARCIS (Netherlands)

    Aratchige, N.S.; Lesna, I.; Sabelis, M.W.

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract

  11. Tarantula spider

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002855.htm Tarantula spider bite To use the sharing features on this ... This article describes the effects of a tarantula spider bite. The class of insects to which the ...

  12. Phylogenetic analysis of the spider mite sub-family Tetranychinae (Acari: Tetranychidae based on the mitochondrial COI gene and the 18S and the 5' end of the 28S rRNA genes indicates that several genera are polyphyletic.

    Directory of Open Access Journals (Sweden)

    Tomoko Matsuda

    Full Text Available The spider mite sub-family Tetranychinae includes many agricultural pests. The internal transcribed spacer (ITS region of nuclear ribosomal RNA genes and the cytochrome c oxidase subunit I (COI gene of mitochondrial DNA have been used for species identification and phylogenetic reconstruction within the sub-family Tetranychinae, although they have not always been successful. The 18S and 28S rRNA genes should be more suitable for resolving higher levels of phylogeny, such as tribes or genera of Tetranychinae because these genes evolve more slowly and are made up of conserved regions and divergent domains. Therefore, we used both the 18S (1,825-1,901 bp and 28S (the 5' end of 646-743 bp rRNA genes to infer phylogenetic relationships within the sub-family Tetranychinae with a focus on the tribe Tetranychini. Then, we compared the phylogenetic tree of the 18S and 28S genes with that of the mitochondrial COI gene (618 bp. As observed in previous studies, our phylogeny based on the COI gene was not resolved because of the low bootstrap values for most nodes of the tree. On the other hand, our phylogenetic tree of the 18S and 28S genes revealed several well-supported clades within the sub-family Tetranychinae. The 18S and 28S phylogenetic trees suggest that the tribes Bryobiini, Petrobiini and Eurytetranychini are monophyletic and that the tribe Tetranychini is polyphyletic. At the genus level, six genera for which more than two species were sampled appear to be monophyletic, while four genera (Oligonychus, Tetranychus, Schizotetranychus and Eotetranychus appear to be polyphyletic. The topology presented here does not fully agree with the current morphology-based taxonomy, so that the diagnostic morphological characters of Tetranychinae need to be reconsidered.

  13. Comparação econômica entre controle biológico e químico para o manejo de ácaro-vermelho em macieira Economic comparison of biological and chemical control in the management of red spider mites in apple orchard

    Directory of Open Access Journals (Sweden)

    Lino Bittencourt Monteiro

    2006-12-01

    Full Text Available O ácaro-vermelho da macieira, Panonychus ulmi (Acari: Tetranychidae, é uma importante praga na cultura da macieira em Fraiburgo - SC, e o controle biológico aplicado foi implantado em meados dos anos 90. O objetivo deste trabalho foi demonstrar os benefícios econômicos da utilização do controle biológico no manejo do ácaro-vermelho. A avaliação foi realizada em dois pomares comerciais de macieiras. Em um deles, foi implantado o controle biológico aplicado de ácaros, baseado na liberação do ácaro predador Neoseiulus californicus (Acari: Phytoseiidae, seleção de inseticidas e manejo de ervas invasoras, e o outro pomar seguiu o manejo convencional de artrópodes, baseado na aplicação de produtos químicos para o controle de insetos, ácaros fitófagos e ervas invasoras. A análise econômica mostrou que os custos com mão-de-obra e máquinas foram semelhantes em ambos os pomares, entretanto os custos com acaricidas foram significativamente inferiores no pomar onde o manejo foi o controle biológico, demonstrando que, apesar da necessidade de investimentos em instalações para a criação do ácaro predador e custos de manutenção das mesmas, a estratégia biológica foi economicamente viável.Red spider mite, Panonychus ulmi (Acari: Tetranychidae is a significant pest in apple tree in Fraiburgo, Santa Catarina (SC and applied biological control was implemented in the mid-nineties. The objective of this study was to demonstrate the economic benefits of biological control in the management of red spider mite. The assessment was carried out in two commercial orchards, one of which was subjected to biological control of spider mite by releasing the predator Neoseiulus californicus, insecticide selection and weed management, and the other to conventional arthropod management, based on the application of chemicals to control insects, phytofagous mites and weed. Economic analysis showed that the costs for labor and machines were

  14. Health effects of predatory beneficial mites and wasps in greenhouses

    DEFF Research Database (Denmark)

    Bælum, Jesper; Enkegaard, Annie; Doekes, Gert

    A three-year study of 579 greenhouse workers in 31 firms investigated the effect of four different beneficial arthropods. It was shown that the thrips mite Amblyseeius cucumeris and the spider mite predator Phytoseiulus persimilis may cause allergy measured by blood tests as well as eye and nose...... symptoms. No effect was seen by the predator wasp Aphidius colemani nor the predator mite Hypoaspis miles and no effect on lung diseases were seen....

  15. Tetranychus urticae mites do not mount an induced immune response against bacteria.

    Science.gov (United States)

    Santos-Matos, Gonçalo; Wybouw, Nicky; Martins, Nelson E; Zélé, Flore; Riga, Maria; Leitão, Alexandre B; Vontas, John; Grbić, Miodrag; Van Leeuwen, Thomas; Magalhães, Sara; Sucena, Élio

    2017-06-14

    The genome of the spider mite Tetranychus urticae , a herbivore, is missing important elements of the canonical Drosophila immune pathways necessary to fight bacterial infections. However, it is not known whether spider mites can mount an immune response and survive bacterial infection. In other chelicerates, bacterial infection elicits a response mediated by immune effectors leading to the survival of infected organisms. In T. urticae , infection by either Escherichia coli or Bacillus megaterium did not elicit a response as assessed through genome-wide transcriptomic analysis. In line with this, spider mites died within days even upon injection with low doses of bacteria that are non-pathogenic to Drosophila Moreover, bacterial populations grew exponentially inside the infected spider mites. By contrast, Sancassania berlesei , a litter-dwelling mite, controlled bacterial proliferation and resisted infections with both Gram-negative and Gram-positive bacteria lethal to T. urticae This differential mortality between mite species was absent when mites were infected with heat-killed bacteria. Also, we found that spider mites harbour in their gut 1000-fold less bacteria than S. berlesei We show that T. urticae has lost the capacity to mount an induced immune response against bacteria, in contrast to other mites and chelicerates but similarly to the phloem feeding aphid Acyrthosiphon pisum Hence, our results reinforce the putative evolutionary link between ecological conditions regarding exposure to bacteria and the architecture of the immune response. © 2017 The Authors.

  16. Interactions in a tritrophic acarine predator-prey metapopulation system V: Within-plant dynamics of Phytoseiulus persimilis and Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae)

    DEFF Research Database (Denmark)

    Nachman, Gösta; Zemek, Rostislav

    2003-01-01

    Biological control, Bottom-up factor, Phytoseiulus persimilis, Plant condition, Predacious mites, Simulation model, Tetranychus urticae, Top-down factor, Two-spotted spider mites......Biological control, Bottom-up factor, Phytoseiulus persimilis, Plant condition, Predacious mites, Simulation model, Tetranychus urticae, Top-down factor, Two-spotted spider mites...

  17. An analysis of potential resistance of the phytophagous mite, Tetranychus urticae Koch (Acari: Tetranychidae to four botanical pesticides

    Directory of Open Access Journals (Sweden)

    Attia, S.

    2015-01-01

    Full Text Available Description of the subject. Synthetic acaricides have been widely used to manage Tetranychus urticae. Due to the excessive use of biocide and the associated problems of pesticide resistance and environmental pollution, there is an increasing demand for sustainable, environmentally-friendly control methods. Among the current alternative strategies aimed at decreasing the pest populations, the pesticides based on plant extracts are currently one of the most promising methods. Essential oils with acaricidal properties have been categorized as green pesticides because they are biodegradable and predominantly non-toxic to vertebrates. Objectives. With an aim to reduce the use of synthetic pesticides, they represent a promising approach for eco-chemical control of mites. Method. The aim of the present work was to analyze the risk of resistance emergence of T. urticae to repeated treatments with four plant extracts: Deverra scoparia Coss. & Durieu (Araliales: Apiaceae, Hertia cheirifolia (L. Kuntze (Asterales: Ateraceae, Santolina africana Jord. & Fourr. (Asterales: Asteraceae essential oils and garlic distillate Allium sativum L. (Asparagales: Alliaceae after 20 generations. Results. Repeated treatments with S. africana essential oil during 20 generations did not provoke an emergence of resistance while a low development of resistance was observed with H. cheirifolia, A. sativum and D. scoparia extracts. Conclusions. The efficacy of these extracts against the two spotted spider mite and their low development of resistance make them a promising use for pest management.

  18. Vulnerability and behavioral response to ultraviolet radiation in the components of a foliar mite prey-predator system

    Science.gov (United States)

    Tachi, Fuyuki; Osakabe, Masahiro

    2012-12-01

    Ambient ultraviolet-B (UVB) radiation impacts plant-dwelling arthropods including herbivorous and predatory mites. However, the effects of UVB on prey-predator systems, such as that between the herbivorous spider mite and predatory phytoseiid mite, are poorly understood. A comparative study was conducted to determine the vulnerability and behavioral responses of these mites to ultraviolet (UV) radiation. First, we analyzed dose-response (cumulative irradiance-mortality) curves for the eggs of phytoseiid mites ( Neoseiulus californicus, Neoseiulus womersleyi, and Phytoseiulus persimilis) and the spider mite ( Tetranychus urticae) to UVB radiation from a UV lamp. This indicated that the phytoseiid mites were more vulnerable than the spider mite, although P. persimilis was slightly more tolerant than the other two phytoseiid mites. Second, we compared the avoidance behavior of adult female N. californicus and two spider mite species ( T. urticae, a lower leaf surface user; Panonychus citri, an upper leaf surface user) in response to solar UV and visible light. N. californicus actively avoided both types of radiation, whereas P. citri showed only minimal avoidance behavior. T. urticae actively avoided UV as well as N. californicus but exhibited a slow response to visible light as well as P. citri. Such variation in vulnerability and avoidance behavior accounts for differences in the species adaptations to solar UVB radiation. This may be the primary factor determining habitat use among these mites on host plant leaves, subsequently affecting accessibility by predators and also intraguild competition.

  19. Reproduction of two-spotted goby, Gobiusculus flavescens, in captivity

    Directory of Open Access Journals (Sweden)

    Vera Teles

    2014-06-01

    Full Text Available The two-spotted goby, Gobiusculus flavescens, is a common fish species along rocky shores in northern European waters. It is a small (40-60 mm, semipelagic marine fish, forming loose shoals in association with microalgae vegetation and mussel beds growing on the rock surface. It is a short-lived species, with a life span of 1-2 years. Both sexes display courtship behaviour and have sexual ornamentation during the breeding season. Male ornaments consist of large dorsal fins with iridescent blue lines, and iridescent blue spots along the sides of the body. Females develop a conspicuous, bright orange belly at sexual maturity. Due to these characteristics this species could have a great interest for ornamental aquariums. In previous work the maintenance of G. flavescens at high temperatures (until 23°C was successful. The aim of this study was to test the reproduction in captivity of G. flavescens. Six replicates were used (18L aquariums at the temperature of 18°C. In each replicate, two males and four females were introduced to an aquarium, where the males chose between two nests and courted the females. During the 112 days of the experiment the females spawned five times but only three spawns had success. The eggs take approximately 8 days to become mature. On the three spawns have hatched 300, 361 and 510 larvae at a time. The larvae were kept in a separate container and fed with alive rotifers and survived a maximum of 21 days. The reproduction of the two-spotted goby in captivity is possible at 18°C, but it is necessary to improve the conditions to rearing the larvae.

  20. Dehydration Stress Contributes to the Enhancement of Plant Defense Response and Mite Performance on Barley

    Directory of Open Access Journals (Sweden)

    M. E. Santamaria

    2018-04-01

    Full Text Available Under natural conditions, plants suffer different stresses simultaneously or in a sequential way. At present, the combined effect of biotic and abiotic stressors is one of the most important threats to crop production. Understanding how plants deal with the panoply of potential stresses affecting them is crucial to develop biotechnological tools to protect plants. As well as for drought stress, the economic importance of the spider mite on agriculture is expected to increase due to climate change. Barley is a host of the polyphagous spider mite Tetranychus urticae and drought produces important yield losses. To obtain insights on the combined effect of drought and mite stresses on the defensive response of this cereal, we have analyzed the transcriptomic responses of barley plants subjected to dehydration (water-deficit treatment, spider mite attack, or to the combined dehydration-spider mite stress. The expression patterns of mite-induced responsive genes included many jasmonic acid responsive genes and were quickly induced. In contrast, genes related to dehydration tolerance were later up-regulated. Besides, a higher up-regulation of mite-induced defenses was showed by the combined dehydration and mite treatment than by the individual mite stress. On the other hand, the performance of the mite in dehydration stressed and well-watered plants was tested. Despite the stronger defensive response in plants that suffer dehydration and mite stresses, the spider mite demonstrates a better performance under dehydration condition than in well-watered plants. These results highlight the complexity of the regulatory events leading to the response to a combination of stresses and emphasize the difficulties to predict their consequences on crop production.

  1. Dehydration Stress Contributes to the Enhancement of Plant Defense Response and Mite Performance on Barley

    Science.gov (United States)

    Santamaria, M. E.; Diaz, Isabel; Martinez, Manuel

    2018-01-01

    Under natural conditions, plants suffer different stresses simultaneously or in a sequential way. At present, the combined effect of biotic and abiotic stressors is one of the most important threats to crop production. Understanding how plants deal with the panoply of potential stresses affecting them is crucial to develop biotechnological tools to protect plants. As well as for drought stress, the economic importance of the spider mite on agriculture is expected to increase due to climate change. Barley is a host of the polyphagous spider mite Tetranychus urticae and drought produces important yield losses. To obtain insights on the combined effect of drought and mite stresses on the defensive response of this cereal, we have analyzed the transcriptomic responses of barley plants subjected to dehydration (water-deficit) treatment, spider mite attack, or to the combined dehydration-spider mite stress. The expression patterns of mite-induced responsive genes included many jasmonic acid responsive genes and were quickly induced. In contrast, genes related to dehydration tolerance were later up-regulated. Besides, a higher up-regulation of mite-induced defenses was showed by the combined dehydration and mite treatment than by the individual mite stress. On the other hand, the performance of the mite in dehydration stressed and well-watered plants was tested. Despite the stronger defensive response in plants that suffer dehydration and mite stresses, the spider mite demonstrates a better performance under dehydration condition than in well-watered plants. These results highlight the complexity of the regulatory events leading to the response to a combination of stresses and emphasize the difficulties to predict their consequences on crop production. PMID:29681917

  2. Ocorrência do ácaro vermelho europeu Panonychus ulmi (Koch (Tetranychidae associado à cultura da videira no Rio Grande do Sul, Brasil European red spider mite Panonychus ulmi (Koch (Tetranychidae occurrence of vineyards in Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Noeli Juarez Ferla

    2008-09-01

    Full Text Available Neste artigo é descrita ocorrência e o dano causado pelo ácaro vermelho europeu Panonychus ulmi (Koch associado à cultura da videira. As coletas foram realizadas na safra 2005-2006 em Vitis vinifera L. da cultivar Merlot, nos municípios de Bento Gonçalves e Candiota, no Estado do Rio Grande do Sul, Brasil. As folhas infestadas apresentaram bronzeamento, com manchas avermelhadas na face adaxial, resultando na queda prematura das mesmas. Esse é o primeiro registro do ácaro vermelho europeu danificando a cultura da videira no Rio Grande do Sul.The occurrence and the damage caused for the European red spider mite Panonychus ulmi (Koch associated to the culture of the grapevine are described. The collections had been carried through in 2005-2006 seasons in Vitis vinifera L. of cultivating Merlot in Bento Gonçalves and Candiota counties, in the state of Rio Grande do Sul, Brazil. The infested leaves had presented bronzing, with spots redly in the adaxial face resulting in the premature fall. This is the first register of the European red mite damaging the culture of the grapevine in Rio Grande do Sul.

  3. SPIDER SILK

    Directory of Open Access Journals (Sweden)

    PORAV Viorica

    2014-05-01

    Full Text Available The strengthness and toughness of spider fiber and its multifunctional nature is only surpassed in some cases by synthetic high performance fibers. In the world of natural fibers, spider silk has been long time recognized as a wonder fiber for its unique combination of high strength and rupture elongation. Scientists in civil military engineering reveal that the power of biological material (spider silk lies in the geometric configuration of structural protein, and the small cluster of week hydrogen bonds that works together to resist force and dissipate energy. Each spider and each type of silk has a set of mechanical properties optimized for their biological function. Most silks, in particular deagline silk, have exceptional mechanical properties. They exhibit a unique combination of high tensile strength and extensibility (ductility. This enables a silk fiber to absorb a lot of energy before breaking (toughness, the area under a stress- strain curve. A frequent mistake made in the mainstream media is to confuse strength and toughness when comparing silk to other materials. As shown below in detail, weight for weight, silk is stronger than steel, but not as strong as Kevlar. Silk is,however, tougher than both.This paper inform about overview on the today trend in the world of spider silk.

  4. Spider Vein Removal

    Science.gov (United States)

    Spider veins: How are they removed? I have spider veins on my legs. What options are available ... M.D. Several options are available to remove spider veins — thin red lines or weblike networks of ...

  5. Spider Bites (For Parents)

    Science.gov (United States)

    ... Videos for Educators Search English Español First Aid: Spider Bites KidsHealth / For Parents / First Aid: Spider Bites ... rare. Signs and Symptoms Of a brown recluse spider bite: red blister in the center with surrounding ...

  6. SIMULTANEOUS PRODUCTIVE GROWTH GROUPS (SPGG: INNOVATION ON PAPAYA MITE MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Marycruz Abato-Zárate

    2011-11-01

    Full Text Available Grower’s previous experience and their ability to communicate technical information to other growers, allows greater adoption of technologies. Thus, appropriation of technologies of mite management and sampling was evaluated, based on the “Simultaneous Productive Growth Groups (SPGG” technology transfer model. A preliminary diagnosis was made, evaluating the technology transfer achieved by six leading growers showing up continuously to seven meetings carried out from March to July 2010, and also by 19 growers showing up on a more irregular basis. All growers were from the municipality of Cotaxtla and belonged to the Papaya-Product-System of Veracruz, Mexico. Participation, attitude and efficacy of training were evaluated with a survey. Forty-two percent of growers considered the papaya ring spot virus as the main problem and 48 % revealed spider mites as the second one; 96 % used pesticides on spider mites. Participation of the SPGG basic group was 71 %, who agreed on sampling, recording data in sampling forms and using selective acaricides. Seventy percent were able to recognize spider mites from predatory mites and 83 % recognized selective acaricides. Growers considered that sampling can help reduce control costs. The SPGG model allowed building collective knowledge and better decision making by the working group.

  7. Spider Bites: First Aid

    Science.gov (United States)

    ... care immediately if: You were bitten by a black widow or brown recluse spider You are unsure whether the bite ... in the South. Signs and symptoms of a black widow spider bite may include: At ... fever and nausea Brown recluse spider The brown recluse spider has a ...

  8. Response of predatory mites to a herbivore-induced plant volatile: genetic variation for context-dependent behaviour.

    Science.gov (United States)

    Sznajder, Beata; Sabelis, Maurice W; Egas, Martijn

    2010-07-01

    Plants infested with herbivores release specific volatile compounds that are known to recruit natural enemies. The response of natural enemies to these volatiles may be either learned or genetically determined. We asked whether there is genetic variation in the response of the predatory mite Phytoseiulus persimilis to methyl salicylate (MeSa). MeSa is a volatile compound consistently produced by plants being attacked by the two-spotted spider mite, the prey of P. persimilis. We predicted that predators express genetically determined responses during long-distance migration where previously learned associations may have less value. Additionally, we asked whether these responses depend on odors from uninfested plants as a background to MeSa. To infer a genetic basis, we analyzed the variation in response to MeSa among iso-female lines of P. persimilis by using choice-tests that involved either (1) MeSa presented as a single compound or (2) MeSa with background-odor from uninfested lima bean plants. These tests were conducted for starved and satiated predators, i.e., two physiological states, one that approximates migration and another that mimics local patch exploration. We found variation among iso-female lines in the responses to MeSa, thus showing genetic variation for this behavior. The variation was more pronounced in the starved predators, thus indicating that P. persimilis relies on innate preferences when migrating. Background volatiles of uninfested plants changed the predators' responses to MeSa in a manner that depended on physiological state and iso-female line. Thus, it is possible to select for context-dependent behavioral responses of natural enemies to plant volatiles.

  9. Mite Pests in Plant Crops – Current Issues, Inovative Approaches and Possibilities for Controlling Them (1

    Directory of Open Access Journals (Sweden)

    Radmila Petanović

    2010-01-01

    Full Text Available In the middle of the last century, mites moved into the focus of attention as pests relevantto agriculture, forestry and landscape horticulture, presumably in direct reactionto the “green revolution” that involved plant cultivation in large-plot monocropping systems,improved methods of cultivation, selection of high-yielding cultivars and intensifieduse of pesticides and mineral fertilizers. Agroecosystems in which phytophagous miteshave become harmful organisms are primarily orchards, vineyards, greenhouses, urbangreeneries, plant nurseries and stored plant products, as well as annual field crops to asomewhat lesser degree. Phytophagous mite species belong to a variety of spider mites(Tetranychidae, false spider mites (Tenuipalpidae, gall and rust mites (Eriophyoidae, tarsonemidmites (Tarsonemidae and acarid mites (Acaridae. Most of these harmful speciesare widespread, some of them having more economic impact than others and being moredetrimental as depending on various specificities of each outdoor agroecosystem in anyparticular climatic region.The first segment of this overview focuses on the most significant mite pests ofagroecosystemsand urban horticultural areas in European countries, our own region andin Serbia today, primarily on species that have caused problems in recent years regardingplant production, and it also discusses various molecular methods available for investigatingdifferent aspects of the biology of phytophagous mites. Also, acaricides are discussedas a method of controlling mite pests in the light of the current situation and trends on pesticidemarkets in Serbia and the European Union member-countries

  10. Food stress causes sex-specific maternal effects in mites.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2015-08-01

    Life history theory predicts that females should produce few large eggs under food stress and many small eggs when food is abundant. We tested this prediction in three female-biased size-dimorphic predatory mites feeding on herbivorous spider mite prey: Phytoseiulus persimilis, a specialized spider mite predator; Neoseiulus californicus, a generalist preferring spider mites; Amblyseius andersoni, a broad diet generalist. Irrespective of predator species and offspring sex, most females laid only one small egg under severe food stress. Irrespective of predator species, the number of female but not male eggs decreased with increasing maternal food stress. This sex-specific effect was probably due to the higher production costs of large female than small male eggs. The complexity of the response to the varying availability of spider mite prey correlated with the predators' degree of adaptation to this prey. Most A. andersoni females did not oviposit under severe food stress, whereas N. californicus and P. persimilis did oviposit. Under moderate food stress, only P. persimilis increased its investment per offspring, at the expense of egg number, and produced few large female eggs. When prey was abundant, P. persimilis decreased the female egg sizes at the expense of increased egg numbers, resulting in a sex-specific egg size/number trade-off. Maternal effects manifested only in N. californicus and P. persimilis. Small egg size correlated with the body size of daughters but not sons. Overall, our study provides a key example of sex-specific maternal effects, i.e. food stress during egg production more strongly affects the sex of the large than the small offspring. © 2015. Published by The Company of Biologists Ltd.

  11. Brown Recluse Spider

    Science.gov (United States)

    ... to a group of spiders commonly known as violin spiders or fiddlebacks. The characteristic fiddle-shaped pattern ... 4-19.1mm) • Color: Golden brown • A dark violin/fiddle shape (see top photo) is located on ...

  12. Nature Study Tips. Spiders.

    Science.gov (United States)

    Mulaik, Stanley B.

    1990-01-01

    Different types of spiders, their ranges and habits are discussed. Activities associated with the study of spiders are suggested. Four references are listed which may be of interest to beginners. (CW)

  13. Black widow spider

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002858.htm Black widow spider To use the sharing features on this page, please enable JavaScript. The black widow spider (Latrodectus) has a shiny black body with a ...

  14. Did You Say Spiders?

    Science.gov (United States)

    Campbell, Alene

    This spider unit focuses on students' development of cooperative learning and inquiry-based skills. Students read "The Very Busy Spider" by Eric Carle, and then work in cooperative groups using the Internet to research and synthesize important information about spiders. Technology is used for vocabulary instruction and to create a…

  15. Spiders in dermatology.

    Science.gov (United States)

    Kang, Jun K; Bhate, Chinmoy; Schwartz, Robert A

    2014-09-01

    Spider bites represent an unusual and potentially over-represented clinical diagnosis. Despite a common fear of spiders, known as arachnophobia, current knowledge suggests that only a small number of families within the order Araneae are medically relevant. Moreover, most cutaneous spider reactions, including both evenomations and physical trauma, produce mild, local symptoms which may be managed with supportive care alone. The differential diagnosis for spider bites may be broad, especially if the offending arachnid is not seen or found. We describe a series of spiders relevant to the dermatologist in the United States.

  16. Attending to detail by communal spider-eating spiders.

    Science.gov (United States)

    Jackson, Robert R; Nelson, Ximena J

    2012-07-01

    Communal predators may often need to make especially intricate foraging decisions, as a predator's success may depend on the actions of its neighbours. Here,we consider the decisions made by Portia africana, a jumping spider (Salticidae) that preys on other spiders, including Oecobius amboseli (Oecobiidae), a small prey spider that lives under small sheets of silk (nests) on the walls of buildings. P. africana juveniles settle near oecobiid nests and then ambush oecobiids as they leave or enter the nest. Two or more P. africana juveniles sometimes settle at the same nest and, when an oecobiid is captured, the P. africana juveniles may share the meal. We investigated the joining decisions made by naïve P. africana juveniles. Experiments were based on using lures (dead spiders positioned in lifelike posture) arranged in a series of 17 different scenes defined by the presence/absence of a nest, the lure types present and the configuration of the lures and the nest. Our findings imply that P. africana juveniles make remarkably precise predatory decisions, with the variables that matter including whether a nest is present, the identity of spiders inside and outside a nest and how spiders are positioned relative to each other and the nest.

  17. Funnel-web spider bite

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002844.htm Funnel-web spider bite To use the sharing features on ... the effects of a bite from the funnel-web spider. Male funnel-web spiders are more poisonous ...

  18. Spiders in caves.

    Science.gov (United States)

    Mammola, Stefano; Isaia, Marco

    2017-04-26

    World experts of different disciplines, from molecular biology to macro-ecology, recognize the value of cave ecosystems as ideal ecological and evolutionary laboratories. Among other subterranean taxa, spiders stand out as intriguing model organisms for their ecological role of top predators, their unique adaptations to the hypogean medium and their sensitivity to anthropogenic disturbance. As the description of the first eyeless spider ( Stalita taenaria ), an array of papers on subterranean spider biology, ecology and evolution has been published, but a comprehensive review on these topics is still lacking. We provide a general overview of the spider families recorded in hypogean habitats worldwide, we review the different adaptations of hypogean spiders to subterranean life, and we summarize the information gathered so far about their origin, population structure, ecology and conservation status. Finally, we point out the limits of the knowledge we currently have regarding hypogean spiders, aiming to stimulate future research. © 2017 The Author(s).

  19. Respiration in spiders (Araneae).

    Science.gov (United States)

    Schmitz, Anke

    2016-05-01

    Spiders (Araneae) are unique regarding their respiratory system: they are the only animal group that breathe simultaneously with lungs and tracheae. Looking at the physiology of respiration the existence of tracheae plays an important role in spiders with a well-developed tracheal system. Other factors as sex, life time, type of prey capture and the high ability to gain energy anaerobically influence the resting and the active metabolic rate intensely. Most spiders have metabolic rates that are much lower than expected from body mass; but especially those with two pairs of lungs. Males normally have higher resting rates than females; spiders that are less evolved and possess a cribellum have lower metabolic rates than higher evolved species. Freely hunting spiders show a higher energy turnover than spiders hunting with a web. Spiders that live longer than 1 year will have lower metabolic rates than those species that die after 1 year in which development and reproduction must be completed. Lower temperatures and starvation, which most spiders can cope with, will decrease the metabolic rate as well.

  20. Toxicity of bifenazate and its principal active metabolite, diazene, to Tetranychus urticae and Panonychus citri and their relative toxicity to the predaceous mites, Phytoseiulus persimilis and Neoseiulus californicus.

    Science.gov (United States)

    Ochiai, Noriaki; Mizuno, Masayuki; Mimori, Norihiko; Miyake, Toshihiko; Dekeyser, Mark; Canlas, Liza Jara; Takeda, Makio

    2007-01-01

    Bifenazate is a novel carbazate acaricide discovered by Uniroyal Chemical (now Chemtura Corporation) for the control of phytophagous mites infesting agricultural and ornamental crops. Its acaricidal activity and that of its principal active metabolite, diazene, were characterized. Bifenazate and diazene had high toxicity and specificity both orally and topically to all life stages of Tetranychus urticae and Panonychus citri. Acute poisoning was observed with no temperature dependency. No cross-resistance was found to mites resistant to several other classes of acaricides, such as tebufenpyrad, etoxazole, fenbutatin oxide and dicofol. Bifenazate remained effective for a long time with only about a 10% loss of efficacy on T. urticae after 1 month of application in the field. All stages of development of the predatory mites, Phytoseiulus persimilis and Neoseiulus californicus, survived treatment by both bifenazate and diazene. When adult females of the two predatory mite species were treated with either bifenazate or diazene, they showed a normal level of fecundity and predatory activity in the laboratory, effectively suppressing spider mite population growth. Even when the predators were fed spider mite eggs that had been treated previously with bifenazate, they survived. These findings indicate that bifenazate is a very useful acaricide giving high efficacy, long-lasting activity and excellent selectivity for spider mites. It is, therefore, concluded that bifenazate is an ideal compound for controlling these pest mites.

  1. The economic importance of acaricides in the control of phytophagous mites and an update on recent acaricide mode of action research.

    Science.gov (United States)

    Van Leeuwen, Thomas; Tirry, Luc; Yamamoto, Atsushi; Nauen, Ralf; Dermauw, Wannes

    2015-06-01

    Acaricides are one of the cornerstones of an efficient control program for phytophagous mites. An analysis of the global acaricide market reveals that spider mites such as Tetranychus urticae, Panonychus citri and Panonychus ulmi are by far the most economically important species, representing more than 80% of the market. Other relevant mite groups are false spider mites (mainly Brevipalpus), rust and gall mites and tarsonemid mites. Acaricides are most frequently used in vegetables and fruits (74% of the market), including grape vines and citrus. However, their use is increasing in major crops where spider mites are becoming more important, such as soybean, cotton and corn. As revealed by a detailed case study of the Japanese market, major shifts in acaricide use are partially driven by resistance development and the commercial availability of compounds with novel mode of action. The importance of the latter cannot be underestimated, although some compounds are successfully used for more than 30 years. A review of recent developments in mode of action research is presented, as such knowledge is important for devising resistance management programs. This includes spirocyclic keto-enols as inhibitors of acetyl-CoA carboxylase, the carbazate bifenazate as a mitochondrial complex III inhibitor, a novel class of complex II inhibitors, and the mite growth inhibitors hexythiazox, clofentezine and etoxazole that interact with chitin synthase I. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Bat Predation by Spiders

    Science.gov (United States)

    Nyffeler, Martin; Knörnschild, Mirjam

    2013-01-01

    In this paper more than 50 incidences of bats being captured by spiders are reviewed. Bat-catching spiders have been reported from virtually every continent with the exception of Antarctica (∼90% of the incidences occurring in the warmer areas of the globe between latitude 30° N and 30° S). Most reports refer to the Neotropics (42% of observed incidences), Asia (28.8%), and Australia-Papua New Guinea (13.5%). Bat-catching spiders belong to the mygalomorph family Theraphosidae and the araneomorph families Nephilidae, Araneidae, and Sparassidae. In addition to this, an attack attempt by a large araneomorph hunting spider of the family Pisauridae on an immature bat was witnessed. Eighty-eight percent of the reported incidences of bat catches were attributable to web-building spiders and 12% to hunting spiders. Large tropical orb-weavers of the genera Nephila and Eriophora in particular have been observed catching bats in their huge, strong orb-webs (of up to 1.5 m diameter). The majority of identifiable captured bats were small aerial insectivorous bats, belonging to the families Vespertilionidae (64%) and Emballonuridae (22%) and usually being among the most common bat species in their respective geographic area. While in some instances bats entangled in spider webs may have died of exhaustion, starvation, dehydration, and/or hyperthermia (i.e., non-predation death), there were numerous other instances where spiders were seen actively attacking, killing, and eating the captured bats (i.e., predation). This evidence suggests that spider predation on flying vertebrates is more widespread than previously assumed. PMID:23516436

  3. Bat predation by spiders.

    Science.gov (United States)

    Nyffeler, Martin; Knörnschild, Mirjam

    2013-01-01

    In this paper more than 50 incidences of bats being captured by spiders are reviewed. Bat-catching spiders have been reported from virtually every continent with the exception of Antarctica (≈ 90% of the incidences occurring in the warmer areas of the globe between latitude 30° N and 30° S). Most reports refer to the Neotropics (42% of observed incidences), Asia (28.8%), and Australia-Papua New Guinea (13.5%). Bat-catching spiders belong to the mygalomorph family Theraphosidae and the araneomorph families Nephilidae, Araneidae, and Sparassidae. In addition to this, an attack attempt by a large araneomorph hunting spider of the family Pisauridae on an immature bat was witnessed. Eighty-eight percent of the reported incidences of bat catches were attributable to web-building spiders and 12% to hunting spiders. Large tropical orb-weavers of the genera Nephila and Eriophora in particular have been observed catching bats in their huge, strong orb-webs (of up to 1.5 m diameter). The majority of identifiable captured bats were small aerial insectivorous bats, belonging to the families Vespertilionidae (64%) and Emballonuridae (22%) and usually being among the most common bat species in their respective geographic area. While in some instances bats entangled in spider webs may have died of exhaustion, starvation, dehydration, and/or hyperthermia (i.e., non-predation death), there were numerous other instances where spiders were seen actively attacking, killing, and eating the captured bats (i.e., predation). This evidence suggests that spider predation on flying vertebrates is more widespread than previously assumed.

  4. Size Dependent Male Reproductive Tactic in the Two-Spotted Goby (Gobiusculus flavescens).

    Science.gov (United States)

    Utne-Palm, A C; Eduard, K; Jensen, K H; Mayer, I; Jakobsen, P J

    2015-01-01

    Male investment in testes and sperm duct gland in the polygamous nest breeding two-spotted goby Gobiusculus flavescens (Fabricius) was investigated in relation to time in reproductive season and individual physical parameters. This small teleost fish is most likely the most abundant species found along the rocky shores of the North East Atlantic. The two-spotted goby has a single reproductive season, during which nest-caring males can raise several clutches of offspring. According to the literature the males are on average larger than the females. Here we report for the first time a population showing a reversal of this trend, with males on average being smaller than females, a difference likely caused by a large proportion of small males. Early in the breeding season these small males have typical sneaker characters, with relatively large testes and small seminal duct glands compared to the larger dominant territorial males. The presence of these two alternative male reproductive tactics is confirmed by histological studies, which shows the presence of sperm in the sperm duct glands (SDG) of smaller males, but not in the SDG of intermediate and larger males. To our knowledge, males with typical sneaker characters have not been reported in earlier studied populations of two-spotted goby. Interestingly we found that testes investment declined significantly over the course of the breeding season, and that this reduction was significantly more pronounced in small compared to the large males. Further, a significant increase in seminal duct gland (SDG) mass was observed for the smaller males over the breeding season. We propose that this indicates a possible shift in mating tactic by smaller males from a parasitic to a nest-holding tactic over the course of the breeding season. Thus, the observed size dependent plasticity in investment in SDG over time suggests that the reproductive tactic of G. flavescens is conditional, and possibly influenced by mate availability and

  5. Size Dependent Male Reproductive Tactic in the Two-Spotted Goby (Gobiusculus flavescens.

    Directory of Open Access Journals (Sweden)

    A C Utne-Palm

    Full Text Available Male investment in testes and sperm duct gland in the polygamous nest breeding two-spotted goby Gobiusculus flavescens (Fabricius was investigated in relation to time in reproductive season and individual physical parameters. This small teleost fish is most likely the most abundant species found along the rocky shores of the North East Atlantic. The two-spotted goby has a single reproductive season, during which nest-caring males can raise several clutches of offspring. According to the literature the males are on average larger than the females. Here we report for the first time a population showing a reversal of this trend, with males on average being smaller than females, a difference likely caused by a large proportion of small males. Early in the breeding season these small males have typical sneaker characters, with relatively large testes and small seminal duct glands compared to the larger dominant territorial males. The presence of these two alternative male reproductive tactics is confirmed by histological studies, which shows the presence of sperm in the sperm duct glands (SDG of smaller males, but not in the SDG of intermediate and larger males. To our knowledge, males with typical sneaker characters have not been reported in earlier studied populations of two-spotted goby. Interestingly we found that testes investment declined significantly over the course of the breeding season, and that this reduction was significantly more pronounced in small compared to the large males. Further, a significant increase in seminal duct gland (SDG mass was observed for the smaller males over the breeding season. We propose that this indicates a possible shift in mating tactic by smaller males from a parasitic to a nest-holding tactic over the course of the breeding season. Thus, the observed size dependent plasticity in investment in SDG over time suggests that the reproductive tactic of G. flavescens is conditional, and possibly influenced by mate

  6. Characterization of microsatellite loci from two-spotted octopus Octopus bimaculatus Verrill 1883 from pyrosequencing reads

    Science.gov (United States)

    Domínguez-Contreras, J. F.; Munguía-Vega, A.; Ceballos-Vázquez, B. P.; Arellano-Martínez, M.; Culver, Melanie

    2014-01-01

    We characterized 22 novel microsatellite loci in the two-spotted octopus Octopus bimaculatus using 454 pyrosequencing reads. All loci were polymorphic and will be used in studies of marine connectivity aimed at increasing sustainability of the resource. The mean number alleles per locus was 13.09 (range 7–19) and observed heterozygosities ranged from 0.50 to 1.00. Four loci pairs were linked and three deviated from Hardy–Weinberg equilibrium. Eighteen and 12 loci were polymorphic in Octopus bimaculoides and Octopus hubbsorum, respectively.

  7. Interactions in a tritrophic acarine predator-prey metapopulation system III

    DEFF Research Database (Denmark)

    Nachman, Gösta; Zemek, R.

    2002-01-01

    Spider mites are serious pests on many economically important plant species, because they may reduce plant productivity and, at high mite densities, overexploit and even kill the host plants. We have conducted a series of greenhouse experiments to quantify the effects of two-spotted spider mites...... (Tetranychus urticae) on host plants (Phaseolusvulgaris). The average amount of chlorophyll per cm2 leaf area was used as a measure of plant condition. It was shown that chlorophyll concentration decreases with plant age and intensity of spider mite feeding. Damage caused by spider mites was assessed visually...... caused by spider mites (D). D takes values between 0 (no injury) and 1 (all leaves dead). A highly significant positive relationship between the instantaneous spider mite density and D was found, even though D is expected to reflect the cumulated density of mites (mite-days). A model of plant growth...

  8. Biomechanics of Spider Silks

    Science.gov (United States)

    2006-03-02

    water and deformation conditions. Such fibres [Nexia ’ biosteel ’ silk ] were spun from recombinant silk ’cloned’ from Spidroin II and indeed show 67...SUBTITLE 5. FUNDING NUMBERS Biomechanics of Spider Silks F49620-03-1-0111 6. AUTHOR(S) Fritz Vollrath 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Perform Pro, WHSIDIOR, Oct 94 COVER SHEET FINAL (3rd Year) Report to AFOSR on: BIOMECHANICS OF SPIDER SILKS Fritz Vollrath, Oxford University, England

  9. Attentional bias to moving spiders in spider fearful individuals.

    Science.gov (United States)

    Vrijsen, Janna N; Fleurkens, Pascal; Nieuwboer, Wieteke; Rinck, Mike

    2009-05-01

    We investigated if an attentional bias for spiders in spider fearful individuals (SFs) can also be found for moving spiders, rather than static images. In Study 1, 28 SFs and 33 non-anxious controls (NACs) participated in a modified version of the dot probe paradigm: they had to react to a probe that appeared either in the next, previous, or side position of a spider's or a wheel's path. 24 SFs and 29 NACs participated in Study 2, in which a fourth, highly predictable, probe position was added. We expected that moving spiders would capture the attention of SFs. In addition, we tested whether SFs try to predict the movement of the spider to make it less threatening. As expected, SFs showed an attentional bias towards moving spiders. However, both groups reacted fastest to unpredictable movements, indicating that SFs and NACs alike anticipate unpredictable spider movements.

  10. Parasitism of Trombidium brevimanum larvae on agrobiont linyphiid spiders from Germany.

    Science.gov (United States)

    Tomić, Vladimir; Mąkol, Joanna; Stamenković, Srdjan; Büchs, Wolfgang; Prescher, Sabine; Sivčev, Ivan; Graora, Draga; Sivčev, Lazar; Gotlin-Čuljak, Tatjana; Dudić, Boris

    2015-08-01

    An experiment on three differently-managed agricultural fields in Ahlum, Germany, which aimed at establishing the impact of different management systems on the biodiversity of predators and decomposers, yielded a significant number of spiders parasitized by larvae of Trombidium brevimanum (Actinotrichida, Parasitengona, Trombidiidae). Spider data from the whole sampling period (September 2010-July 2012), indicated that ectoparasitic larvae were recorded only on spiders in pitfall traps in the period of June-July 2011. In this period, only eight species of Linyphiidae--out of 42 species assigned to nine spider families recorded from the study area--were parasitized by mites; considerable levels of parasitism were recorded on Erigone atra, E. dentipalpis, and Oedothorax apicatus. The highest prevalence of parasitism was recorded on the organic field for E. atra (29%), while on the integrated and conventional fields significantly fewer parasitized spiders were observed. The preferred attachment sites on the spider host were regions with softer cuticle, especially regions on the carapace and on the abdomen, adjacent to the pedicel.

  11. The Spider Files

    Science.gov (United States)

    McDonald, James; Dominguez, Lynn

    2012-01-01

    As children develop misconceptions about animals they believe are dangerous, they also adopt attitudes that are difficult to change. Changing these attitudes is challenging for teachers. One animal that is easy to find but difficult for children to understand is a spider. As with most wild animals, they are difficult to teach about because…

  12. PATHWAYS TO SPIDER PHOBIA

    NARCIS (Netherlands)

    MERCKELBACH, H; ARNTZ, A; ARRINDELL, WA; DEJONG, PJ

    Using a revised version of the Phobic Origin Questionnaire (POQ; Ost, L. G. & Hugdahl, K. Behaviour Research and Therapy, 19,439-477; 1981), the present study examined whether conditioning experiences, modeling experiences, and/or informational learning experiences were more often reported by spider

  13. Spider Web Pattern

    Science.gov (United States)

    2006-01-01

    A delicate pattern, like that of a spider web, appears on top of the Mars residual polar cap, after the seasonal carbon-dioxide ice slab has disappeared. Next spring, these will likely mark the sites of vents when the carbon-dioxide ice cap returns. This Mars Global Surveyor, Mars Orbiter Camera image is about 3-kilometers wide (2-miles).

  14. Mating changes the female dietary preference in the two-spotted cricket, Gryllus bimaculatus

    Directory of Open Access Journals (Sweden)

    Yusuke eTsukamoto

    2014-03-01

    Full Text Available Most insect species exhibit characteristic behavioral changes after mating. Typical post-mating behaviors in female insects include noticeable increases in food intake, elevated oviposition rates, lowered receptivity to courting males, and enhanced immune response. Although it has been reported that mated females of several insect species including the fruit fly, Drosophila melanogaster increase the amount of food intake and change their dietary preferences, the limited number of comparative studies prevent the formulation of generalities regarding post-mating behaviors in other insects in particular amongst orthopteran species. Here, we investigated whether females of the two-spotted cricket, Gryllus bimaculatus, alter their feeding behavior after mating. Although significant differences in the amount of food intake after mating were not observed, all experimental data indicated a clear trend among crickets towards the ingestion of larger quantities of food. Geometric framework analyses revealed that the mated female crickets preferred food with higher protein content compared to virgin female crickets. This implies that this species required different nutritional demands after mating. These findings further expand our understanding of the behavioral and biological changes that are triggered in female insects post-mating, and highlight the potential for this species in investigating the molecular-based nutritional dependent activities that are linked to post-mating behaviors.

  15. Spider-Ant Associations: An Updated Review of Myrmecomorphy, Myrmecophily, and Myrmecophagy in Spiders

    Directory of Open Access Journals (Sweden)

    Paula E. Cushing

    2012-01-01

    Full Text Available This paper provides a summary of the extensive theoretical and empirical work that has been carried out in recent years testing the adaptational significance of various spider-ant associations. Hundreds of species of spiders have evolved close relationships with ants and can be classified as myrmecomorphs, myrmecophiles, or myrmecophages. Myrmecomorphs are Batesian mimics. Their close morphological and behavioral resemblance to ants confers strong survival advantages against visually hunting predators. Some species of spiders have become integrated into the ant society as myrmecophiles or symbionts. These spider myrmecophiles gain protection against their own predators, live in an environment with a stable climate, and are typically surrounded by abundant food resources. The adaptations by which this integration is made possible are poorly known, although it is hypothesized that most spider myrmecophiles are chemical mimics and some are even phoretic on their hosts. The third type of spider-ant association discussed is myrmecophagy—or predatory specialization on ants. A table of known spider myrmecophages is provided as is information on their biology and hunting strategies. Myrmecophagy provides these predators with an essentially unlimited food supply and may even confer other protections to the spiders.

  16. Allergens of mites

    Directory of Open Access Journals (Sweden)

    Emilia Siwak

    2014-04-01

    Full Text Available Mite allergens belong to the group of inhalant allergens and represent antigenic substances which are particutlarly important in the pathogenesis of respiratory system diseases and skin diseases. The most common diseases associated with chronic exposure to these aeroallergens include: allergic rhinitis, bronchial asthma and atopic dermatitis. Mite allergens are simple proteins or glycoproteins with different molecular structures and various biochemical functions. The sensitizing capacity of these proteins is connected from their physicochemical properties. Individual allergens perform, among others, the functions of structural proteins, act as enzymes, transport lipids, bind metal ions, and are capable of glycosylation. In addition, mite allergenic proteases degrade proteins of the skin epithelium-resulting in a weakening of its natural protective barrier-and induce the immune response. The proteases also induce the release of pro-inflammatory cytokines: interleukin-4 (IL-4, interleukin 6 (IL-6, interleukin 8 (IL-8, eotaxin, and granulocyte-macrophage colony-stimulating factor-GM-CSF. The article presents the tertiary structure of major and mid-range mite allergens and their classification. Based on literature reports concerning the chemical structure of allergenic proteins, it was emphasized that the structural differences between homologous proteins with allergenic pozoproperties relate to the distribution of amino acid residues on the surface of the molecule. IgE binding affinity and the similarities and differences in the amino acid sequence of the allergens were also the basis for determining cross-reactivity of allergenic proteins. The paper shows an example of this phenomenon, describing the existence of common allergens for various mite species.

  17. Imbalanced Hemolymph Lipid Levels Affect Feeding Motivation in the Two-Spotted Cricket, Gryllus bimaculatus.

    Directory of Open Access Journals (Sweden)

    Takahiro Konuma

    Full Text Available Insect feeding behavior is regulated by many intrinsic factors, including hemolymph nutrient levels. Adipokinetic hormone (AKH is a peptide factor that modulates hemolymph nutrient levels and regulates the nutritional state of insects by triggering the transfer of lipids into the hemolymph. We recently demonstrated that RNA interference (RNAi-mediated knockdown of the AKH receptor (AKHR reduces hemolymph lipid levels, causing an increase in the feeding frequency of the two-spotted cricket, Gryllus bimaculatus. This result indicated that reduced hemolymph lipid levels might motivate crickets to feed. In the present study, to elucidate whether hemolymph lipid levels contribute to insect feeding behavior, we attempted to manipulate hemolymph lipid levels via the lipophorin (Lp-mediated lipid transferring system in G. bimaculatus. Of the constituent proteins in Lp, we focused on apolipophorin-III (GrybiApoLp-III because of its possible role in facilitating lipid mobilization. First, we used RNAi to reduce the expression of GrybiApoLp-III. RNAi-mediated knockdown of GrybiApoLp-III had little effect on basal hemolymph lipid levels and the amount of food intake. In addition, hemolymph lipid levels remained static even after injecting AKH into GrybiApoLp-IIIRNAi crickets. These observations indicated that ApoLp-III does not maintain basal hemolymph lipid levels in crickets fed ad libitum, but is necessary for mobilizing lipid transfer into the hemolymph following AKH stimulation. Second, Lp (containing lipids was injected into the hemolymph to induce a temporary increase in hemolymph lipid levels. Consequently, the initiation of feeding was delayed in a dose-dependent manner, indicating that increased hemolymph lipid levels reduced the motivation to feed. Taken together, these data validate the importance of basal hemolymph lipid levels in the control of energy homeostasis and for regulating feeding behavior in crickets.

  18. A rapid and non-destructive method to assess leaf injury caused by the cassava green mite, Mononychellus tanajoa (Bondar) (Acarina: Tetranychidae)

    DEFF Research Database (Denmark)

    Tomkiewicz, Jonna; Skovgård, Henrik; Nachman, Gösta

    1993-01-01

    . The difference in photosynthetically active area that arises between uninjured and injured plants over a period of time provides a measure of spider mite injury that can be related to growth and yield. The method integrates the injury inflicted over a period of time, allows successive observations of the same...

  19. Extended spider cognition.

    Science.gov (United States)

    Japyassú, Hilton F; Laland, Kevin N

    2017-05-01

    There is a tension between the conception of cognition as a central nervous system (CNS) process and a view of cognition as extending towards the body or the contiguous environment. The centralised conception requires large or complex nervous systems to cope with complex environments. Conversely, the extended conception involves the outsourcing of information processing to the body or environment, thus making fewer demands on the processing power of the CNS. The evolution of extended cognition should be particularly favoured among small, generalist predators such as spiders, and here, we review the literature to evaluate the fit of empirical data with these contrasting models of cognition. Spiders do not seem to be cognitively limited, displaying a large diversity of learning processes, from habituation to contextual learning, including a sense of numerosity. To tease apart the central from the extended cognition, we apply the mutual manipulability criterion, testing the existence of reciprocal causal links between the putative elements of the system. We conclude that the web threads and configurations are integral parts of the cognitive systems. The extension of cognition to the web helps to explain some puzzling features of spider behaviour and seems to promote evolvability within the group, enhancing innovation through cognitive connectivity to variable habitat features. Graded changes in relative brain size could also be explained by outsourcing information processing to environmental features. More generally, niche-constructed structures emerge as prime candidates for extending animal cognition, generating the selective pressures that help to shape the evolving cognitive system.

  20. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites.

    Science.gov (United States)

    Aratchige, N S; Lesna, I; Sabelis, M W

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract predatory mites (Neoseiulus cucumeris). Since our aim was to demonstrate such odours and not their relevance under soil conditions, the experiments were carried out using a classic Y-tube olfactometer in which the predators moved on a Y-shaped wire in open air. We found that food-deprived female predators can discriminate between odours from infested bulbs and odours from uninfested bulbs or artificially wounded bulbs. No significant difference in attractiveness to predators was found between clean bulbs and bulbs either wounded 30 min or 3 h before the experiment. These results indicate that it may not be simply the wounding of the bulbs, but rather the feeding by rust mites, which causes the bulb to release odours that attract N. cucumeris. Since bulbs are belowground plant structures, the olfactometer results demonstrate the potential for odour-mediated interactions in the soil. However, their importance in the actual soil medium remains to be demonstrated.

  1. Toward improved target conformity for two spot scanning proton therapy delivery systems using dynamic collimation

    Science.gov (United States)

    Moignier, Alexandra; Gelover, Edgar; Smith, Blake R.; Wang, Dongxu; Flynn, Ryan T.; Kirk, Maura L.; Lin, Liyong; Solberg, Timothy D.; Lin, Alexander; Hyer, Daniel E.

    2016-01-01

    Purpose: To quantify improvement in target conformity in brain and head and neck tumor treatments resulting from the use of a dynamic collimation system (DCS) with two spot scanning proton therapy delivery systems (universal nozzle, UN, and dedicated nozzle, DN) with median spot sizes of 5.2 and 3.2 mm over a range of energies from 100 to 230 MeV. Methods: Uncollimated and collimated plans were calculated with both UN and DN beam models implemented within our in-house treatment planning system for five brain and ten head and neck datasets in patients previously treated with spot scanning proton therapy. The prescription dose and beam angles from the clinical plans were used for both the UN and DN plans. The average reduction of the mean dose to the 10-mm ring surrounding the target between the uncollimated and collimated plans was calculated for the UN and the DN. Target conformity was analyzed using the mean dose to 1-mm thickness rings surrounding the target at increasing distances ranging from 1 to 10 mm. Results: The average reductions of the 10-mm ring mean dose for the UN and DN plans were 13.7% (95% CI: 11.6%–15.7%; p < 0.0001) and 11.5% (95% CI: 9.5%–13.5%; p < 0.0001) across all brain cases and 7.1% (95% CI: 4.4%–9.8%; p < 0.001) and 6.3% (95% CI: 3.7%–9.0%; p < 0.001), respectively, across all head and neck cases. The collimated UN plans were either more conformal (all brain cases and 60% of the head and neck cases) than or equivalent (40% of the head and neck cases) to the uncollimated DN plans. The collimated DN plans offered the highest conformity. Conclusions: The DCS added either to the UN or DN improved the target conformity. The DCS may be of particular interest for sites with UN systems looking for a more economical solution than upgrading the nozzle to improve the target conformity of their spot scanning proton therapy system. PMID:26936726

  2. Seleção para alto teor de acilaçúcares em genótipos de tomateiro e sua relação com a resistência ao ácaro vermelho (Tetranychus evansi e à traça (Tuta absoluta Selection towards high acylsugar levels in tomato genotypes and its relationship with resistance to spider mite (Tetranychus evansi and to the South American pinworm (Tuta absoluta

    Directory of Open Access Journals (Sweden)

    Guilherme Victor Nippes Pereira

    2008-06-01

    Lycopersicon pennellii (Correll D'Arcy accession LA-716, acylsugars exsudated by type IV glandular trichomes present in all aerial parts of the plant reportedly mediate resistance to arthropod pests. This paper intended to study the levels of resistance to two arthropod pests, the South American tomato pinworm (Tuta absoluta and spider mites (Tetranychus evansi in tomato genotypes selected solely on the basis of their foliar acylsugar contents. Eleven plants with contrasting acylsugar contents were selected from population F3BC2 derived from the interespecific cross Lycopersicon esculentum 'TOM-584'x Lycopersicon pennellii 'LA-716'. These genotypes were used in tests for resistance/ repellence to the arthropod pests, along with parental checks TOM-584 and LA-716. In Tetranychus spp. mite repellence tests, plants selected for high acylsugar contents behaved similarly to the resistant parent LA-716. Negative and significative correlations between acylsugar contents and distances travelled by the mites onto the leaflet surface indicated an association between the allelochemical and the levels of mite repellence. In the assay with the South American pinworm, these genotypes were evaluated for leaflet lesion type and overall plant damage. The high acylsugar genotypes had good levels of insect resistance, similar to those found in LA-716. In all the evaluation date, acylsugars levels were highly and negatively correlated with pinworm damage. The results indicated that selection for high acylsugar contents was effective in increasing the levels of arthropod resistance of tomato genotypes.

  3. Animal coloration: sexy spider scales.

    Science.gov (United States)

    Taylor, Lisa A; McGraw, Kevin J

    2007-08-07

    Many male jumping spiders display vibrant colors that are used in visual communication. A recent microscopic study on a jumping spider from Singapore shows that three-layered 'scale sandwiches' of chitin and air are responsible for producing their brilliant iridescent body coloration.

  4. Spider Movement, UV Reflectance and Size, but Not Spider Crypsis, Affect the Response of Honeybees to Australian Crab Spiders

    Science.gov (United States)

    Llandres, Ana L.; Rodríguez-Gironés, Miguel A.

    2011-01-01

    According to the crypsis hypothesis, the ability of female crab spiders to change body colour and match the colour of flowers has been selected because flower visitors are less likely to detect spiders that match the colour of the flowers used as hunting platform. However, recent findings suggest that spider crypsis plays a minor role in predator detection and some studies even showed that pollinators can become attracted to flowers harbouring Australian crab spider when the UV contrast between spider and flower increases. Here we studied the response of Apis mellifera honeybees to the presence of white or yellow Thomisus spectabilis Australian crab spiders sitting on Bidens alba inflorescences and also the response of honeybees to crab spiders that we made easily detectable painting blue their forelimbs or abdomen. To account for the visual systems of crab spider's prey, we measured the reflectance properties of the spiders and inflorescences used for the experiments. We found that honeybees did not respond to the degree of matching between spiders and inflorescences (either chromatic or achromatic contrast): they responded similarly to white and yellow spiders, to control and painted spiders. However spider UV reflection, spider size and spider movement determined honeybee behaviour: the probability that honeybees landed on spider-harbouring inflorescences was greatest when the spiders were large and had high UV reflectance or when spiders were small and reflected little UV, and honeybees were more likely to reject inflorescences if spiders moved as the bee approached the inflorescence. Our study suggests that only the large, but not the small Australian crab spiders deceive their preys by reflecting UV light, and highlights the importance of other cues that elicited an anti-predator response in honeybees. PMID:21359183

  5. Spider movement, UV reflectance and size, but not spider crypsis, affect the response of honeybees to Australian crab spiders.

    Science.gov (United States)

    Llandres, Ana L; Rodríguez-Gironés, Miguel A

    2011-02-16

    According to the crypsis hypothesis, the ability of female crab spiders to change body colour and match the colour of flowers has been selected because flower visitors are less likely to detect spiders that match the colour of the flowers used as hunting platform. However, recent findings suggest that spider crypsis plays a minor role in predator detection and some studies even showed that pollinators can become attracted to flowers harbouring Australian crab spider when the UV contrast between spider and flower increases. Here we studied the response of Apis mellifera honeybees to the presence of white or yellow Thomisus spectabilis Australian crab spiders sitting on Bidens alba inflorescences and also the response of honeybees to crab spiders that we made easily detectable painting blue their forelimbs or abdomen. To account for the visual systems of crab spider's prey, we measured the reflectance properties of the spiders and inflorescences used for the experiments. We found that honeybees did not respond to the degree of matching between spiders and inflorescences (either chromatic or achromatic contrast): they responded similarly to white and yellow spiders, to control and painted spiders. However spider UV reflection, spider size and spider movement determined honeybee behaviour: the probability that honeybees landed on spider-harbouring inflorescences was greatest when the spiders were large and had high UV reflectance or when spiders were small and reflected little UV, and honeybees were more likely to reject inflorescences if spiders moved as the bee approached the inflorescence. Our study suggests that only the large, but not the small Australian crab spiders deceive their preys by reflecting UV light, and highlights the importance of other cues that elicited an anti-predator response in honeybees.

  6. Categorizing experience-based foraging plasticity in mites: age dependency, primacy effects and memory persistence.

    Science.gov (United States)

    Schausberger, Peter; Davaasambuu, Undarmaa; Saussure, Stéphanie; Christiansen, Inga C

    2018-04-01

    Behavioural plasticity can be categorized into activational (also termed contextual) and developmental plasticity. Activational plasticity allows immediate contextual behavioural changes, whereas developmental plasticity is characterized by time-lagged changes based on memory of previous experiences (learning). Behavioural plasticity tends to decline with age but whether this holds true for both plasticity categories and the effects of first-in-life experiences is poorly understood. We tackled this issue by assessing the foraging plasticity of plant-inhabiting predatory mites, Amblyseius swirskii , on thrips and spider mites following age-dependent prey experience, i.e. after hatching or after reaching maturity. Juvenile and young adult predator females were alternately presented thrips and spider mites, for establishing 1st and 2nd prey-in-life experiences, and tested, as gravid females, for their foraging plasticity when offered both prey species. Prey experience by juvenile predators resulted in clear learning effects, which were evident in likelier and earlier attacks on familiar prey, and higher proportional inclusion of familiar prey in total diet. First prey-in-life experience by juvenile but not adult predators resulted in primacy effects regarding attack latency. Prey experience by adult predators resulted mainly in prey-unspecific physiological changes, with easy-to-grasp spider mites providing higher net energy gains than difficult-to-grasp thrips. Prey experience by juvenile, but not adult, predators was adaptive, which was evident in a negative correlation between attack latencies and egg production. Overall, our study provides key evidence that similar experiences by juvenile and adult predators, including first-in-life experiences, may be associated with different types of behavioural plasticity, i.e. developmental and activational plasticity.

  7. Categorizing experience-based foraging plasticity in mites: age dependency, primacy effects and memory persistence

    Science.gov (United States)

    Davaasambuu, Undarmaa; Saussure, Stéphanie; Christiansen, Inga C.

    2018-01-01

    Behavioural plasticity can be categorized into activational (also termed contextual) and developmental plasticity. Activational plasticity allows immediate contextual behavioural changes, whereas developmental plasticity is characterized by time-lagged changes based on memory of previous experiences (learning). Behavioural plasticity tends to decline with age but whether this holds true for both plasticity categories and the effects of first-in-life experiences is poorly understood. We tackled this issue by assessing the foraging plasticity of plant-inhabiting predatory mites, Amblyseius swirskii, on thrips and spider mites following age-dependent prey experience, i.e. after hatching or after reaching maturity. Juvenile and young adult predator females were alternately presented thrips and spider mites, for establishing 1st and 2nd prey-in-life experiences, and tested, as gravid females, for their foraging plasticity when offered both prey species. Prey experience by juvenile predators resulted in clear learning effects, which were evident in likelier and earlier attacks on familiar prey, and higher proportional inclusion of familiar prey in total diet. First prey-in-life experience by juvenile but not adult predators resulted in primacy effects regarding attack latency. Prey experience by adult predators resulted mainly in prey-unspecific physiological changes, with easy-to-grasp spider mites providing higher net energy gains than difficult-to-grasp thrips. Prey experience by juvenile, but not adult, predators was adaptive, which was evident in a negative correlation between attack latencies and egg production. Overall, our study provides key evidence that similar experiences by juvenile and adult predators, including first-in-life experiences, may be associated with different types of behavioural plasticity, i.e. developmental and activational plasticity. PMID:29765663

  8. A spider elevator

    Energy Technology Data Exchange (ETDEWEB)

    Butylkin, A.V.; Butylkin, V.A.; Izosimov, A.M.

    1983-01-01

    A spider elevator is proposed which contains a body, a wedge clamp with wedges hinged to each other, a subassembly for holding the wedge clamp in the open and closed positions and a mechanism for changing the wedge clamp, which is made in the form of levers with ears for cleats and installed in the body with the capability of turning. To increase reliability in the operational mode through using the external force for clamping the pipe, the free ends of the levers are hinged with the body by a power cylinder.

  9. The NRL MITE Air Vehicle

    National Research Council Canada - National Science Library

    Kellogg, James; Bovais, Christopher; Dahlburg, Jill; Foch, Richard; Gardner, John; Gordon, Diana; Hartley, Ralph; Kamgar-Parsi, Behrooz; McFarlane, Hugh; Pipitone, Frank; Ramamurti, Ravi; Sciambi, Adam; Spears, William; Srull, Donald; Sullivan, Carol

    2001-01-01

    .... The NRL Micro Tactical Expendable "MITE" air vehicle is a result of this research. The operational MITE is a hand-launched, dual-propeller, fixed-wing air vehicle, with a 9-inch chord and a wingspan of 8 to 18 inches, depending on payload weight...

  10. Smells familiar: group-joining decisions of predatory mites are mediated by olfactory cues of social familiarity.

    Science.gov (United States)

    Muleta, Muluken G; Schausberger, Peter

    2013-09-01

    Group-living animals frequently have to trade off the costs and benefits of leaving an established group and joining another group. Owing to their high fitness relevance, group-joining decisions are commonly nonrandom and may be based on traits of both individual members and the group such as life stage, body size, social status and group density or size, respectively. Many group-living animals are able to recognize and to associate preferentially with familiar individuals, i.e. those encountered before. Hence, after dispersing from established groups, animals commonly have to decide whether to join a new familiar or unfamiliar group. Using binary choice situations we assessed the effects of social familiarity on group-joining behaviour of the plant-inhabiting predatory mite Phytoseiulus persimilis . Group living in P. persimilis is brought about by the patchy distribution of its spider mite prey and mutual conspecific attraction. In the first experiment, gravid predator females given a choice between spider mite patches occupied by unfamiliar and familiar groups of females strongly preferred to join familiar groups and to deposit their eggs in these patches. Preference for socially familiar groups was robust across biases of spider mite prey densities between choice options. The second experiment revealed that the predatory mite females can smell social familiarity from a distance. Females subjected to odour choice situations in artificial cages were more strongly attracted to the odour of familiar than unfamiliar groups. We argue that P. persimilis females preferentially join socially familiar groups because a familiar social environment relaxes competition and optimizes foraging and reproduction.

  11. Smells familiar: group-joining decisions of predatory mites are mediated by olfactory cues of social familiarity☆

    Science.gov (United States)

    Muleta, Muluken G.; Schausberger, Peter

    2013-01-01

    Group-living animals frequently have to trade off the costs and benefits of leaving an established group and joining another group. Owing to their high fitness relevance, group-joining decisions are commonly nonrandom and may be based on traits of both individual members and the group such as life stage, body size, social status and group density or size, respectively. Many group-living animals are able to recognize and to associate preferentially with familiar individuals, i.e. those encountered before. Hence, after dispersing from established groups, animals commonly have to decide whether to join a new familiar or unfamiliar group. Using binary choice situations we assessed the effects of social familiarity on group-joining behaviour of the plant-inhabiting predatory mite Phytoseiulus persimilis. Group living in P. persimilis is brought about by the patchy distribution of its spider mite prey and mutual conspecific attraction. In the first experiment, gravid predator females given a choice between spider mite patches occupied by unfamiliar and familiar groups of females strongly preferred to join familiar groups and to deposit their eggs in these patches. Preference for socially familiar groups was robust across biases of spider mite prey densities between choice options. The second experiment revealed that the predatory mite females can smell social familiarity from a distance. Females subjected to odour choice situations in artificial cages were more strongly attracted to the odour of familiar than unfamiliar groups. We argue that P. persimilis females preferentially join socially familiar groups because a familiar social environment relaxes competition and optimizes foraging and reproduction. PMID:24027341

  12. Population dynamics of interacting predatory mites, Phytoseiulus persimilis and Neoseiulus californicus, held on detached bean leaves.

    Science.gov (United States)

    Walzer, A; Blümel, S; Schausberger, P

    2001-01-01

    The success of combined release of the predatory mites Phytoseiulus persimilis and Neoseiulus californicus in suppression of spider mites may be related to the effects of the interactions between the two predators on their population dynamics. We studied population growth and persistence of the specialist P persimilis and the generalist N. californicus reared singly versus reared in combination after simultaneous and successive predator introductions on detached bean leaf arenas with abundant prey, Tetranychus urticae. and with diminishing prey. When reared singly with abundant prey, either predator population persisted at high densities to the end of the experiment. In every predator combination system with abundant prey and various initial predator:predator ratios N. californicus displaced P persimilis. When held singly with diminishing prey, the population of P. persimilis grew initially faster than the population of N. californicus but both species reached similar population peaks. Irrespective whether reared singly or in combination. N. californicus persisted three to five times longer after prey depletion than did P. persimilis. Regarding the crucial interactions in the predator combination systems, we conclude that intraguild predation was a stronger force than food competition and finally resulted in the displacement of P. persimilis. Previous studies showed that intraguild predation between the specialist P. persimilis and the generalist N. californicus is strongly asymmetric favoring the generalist. We discuss the implications of potential interactions between P. persimilis and N. californicus to biological control of spider mites.

  13. Spiders from Mars?

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-426, 19 July 2003No, this is not a picture of a giant, martian spider web. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a plethora of polygonal features on the floor of a northern hemisphere impact crater near 65.6oN, 327.7oW. The picture was acquired during spring, after the seasonal carbon dioxide frost cap had largely migrated through the region. At the time the picture was taken, remnants of seasonal frost remained on the crater rim and on the edges of the troughs that bound each of the polygons. Frost often provides a helpful hint as to where polygons and patterned ground occur. The polygons, if they were on Earth, would indicate the presence of freeze-thaw cycles in ground ice. Although uncertain, the same might be true of Mars. Sunlight illuminates the scene from the lower left.

  14. Effects of azadirachtin on Tetranychus urticae (Acari: Tetranychidae) and its compatibility with predatory mites (Acari: Phytoseiidae) on strawberry.

    Science.gov (United States)

    Bernardi, Daniel; Botton, Marcos; da Cunha, Uemerson Silva; Bernardi, Oderlei; Malausa, Thibaut; Garcia, Mauro Silveira; Nava, Dori Edson

    2013-01-01

    The spider mite, Tetranychus urticae, is the major strawberry pest in Brazil. The main strategies for its control comprise synthetic acaricides and predatory mites. The recent register of a commercial formula of azadirachtin (Azamax(®) 12 g L(-1) ) can be viable for control of T. urticae. In this work, the effects of azadirachtin on T. urticae and its compatibility with predatory mites Neoseiulus californicus and Phytoseiulus macropilis in the strawberry crop were evaluated. Azadirachtin was efficient against T. urticae, with a mortality rate similar to that of abamectin. In addition, the azadirachtin showed lower biological persistence (7 days) than abamectin (21 days). Azadirachtin did not cause significant mortality of adult predatory mites (N. californicus and P. macropilis), but it did reduce fecundity by 50%. However, egg viability of the azadirachtin treatments was similar to that of the control (>80% viability). The use of azadirachtin and predatory mites is a valuable tool for controlling T. urticae in strawberry crop. Azadirachtin provided effective control of T. urticae and is compatible with the predatory mites N. californicus and P. macropilis. It is an excellent tool to be incorporated into integrated pest management for strawberry crop in Brazil. Copyright © 2012 Society of Chemical Industry.

  15. Sclerotherapy of Varicose Veins and Spider Veins

    Science.gov (United States)

    ... Index A-Z Sclerotherapy of Varicose Veins and Spider Veins Sclerotherapy uses injections from a very fine, ... Sclerotherapy? What is Sclerotherapy of Varicose Veins and Spider Veins? Sclerotherapy is a minimally invasive treatment used ...

  16. Application of 3 kinds of practical electromagnetic spiders in electromagnetic spider web

    OpenAIRE

    Jiang Min

    2016-01-01

    Electromagnetic spider web the launch circuit has introduced a lot, but in the center position of the utility of the spider generally have 3 kinds of circuits respectively, the use of single-chip microcomputer circuit of the low energy consumption spider by multi-channel transmission, single circuit receiver circuit. Direct use of the 3 channels of the spider and the use of PLC circuit spider, depending on the actual situation were placed.

  17. Application of 3 kinds of practical electromagnetic spiders in electromagnetic spider web

    Directory of Open Access Journals (Sweden)

    Jiang Min

    2016-01-01

    Full Text Available Electromagnetic spider web the launch circuit has introduced a lot, but in the center position of the utility of the spider generally have 3 kinds of circuits respectively, the use of single-chip microcomputer circuit of the low energy consumption spider by multi-channel transmission, single circuit receiver circuit. Direct use of the 3 channels of the spider and the use of PLC circuit spider, depending on the actual situation were placed.

  18. Control of poultry red mites

    DEFF Research Database (Denmark)

    Kilpinen, Ole; Steenberg, Tove

    2008-01-01

    The poultry red mite (PRM), Dermanyssus gallinae, is the most important ectoparasite in European egg production. The mites hide in cracks and crevices in the near vicinity of the resting places of the birds, coming out to feed mainly during the night. Under favourable conditions the population can...... grow rapidly, leading to serious problems. Large mite populations may cause anaemia or even death to the poultry, but also in lower numbers mites may be a nuisance to the birds causing decreased egg production and egg quality. Furthermore, they may have the potential of acting as reservoir......-pathogenic fungi and desiccant dust. The dust is diatomaceous earth (of natural origin), synthetic silica products or combinations of the two. The progress of the work with desiccant dusts will be reported. So far, 7 different products have been tested in the laboratory with regard to their efficacy, speed...

  19. Spider phylogenomics: untangling the Spider Tree of Life

    Directory of Open Access Journals (Sweden)

    Nicole L. Garrison

    2016-02-01

    Full Text Available Spiders (Order Araneae are massively abundant generalist arthropod predators that are found in nearly every ecosystem on the planet and have persisted for over 380 million years. Spiders have long served as evolutionary models for studying complex mating and web spinning behaviors, key innovation and adaptive radiation hypotheses, and have been inspiration for important theories like sexual selection by female choice. Unfortunately, past major attempts to reconstruct spider phylogeny typically employing the “usual suspect” genes have been unable to produce a well-supported phylogenetic framework for the entire order. To further resolve spider evolutionary relationships we have assembled a transcriptome-based data set comprising 70 ingroup spider taxa. Using maximum likelihood and shortcut coalescence-based approaches, we analyze eight data sets, the largest of which contains 3,398 gene regions and 696,652 amino acid sites forming the largest phylogenomic analysis of spider relationships produced to date. Contrary to long held beliefs that the orb web is the crowning achievement of spider evolution, ancestral state reconstructions of web type support a phylogenetically ancient origin of the orb web, and diversification analyses show that the mostly ground-dwelling, web-less RTA clade diversified faster than orb weavers. Consistent with molecular dating estimates we report herein, this may reflect a major increase in biomass of non-flying insects during the Cretaceous Terrestrial Revolution 125–90 million years ago favoring diversification of spiders that feed on cursorial rather than flying prey. Our results also have major implications for our understanding of spider systematics. Phylogenomic analyses corroborate several well-accepted high level groupings: Opisthothele, Mygalomorphae, Atypoidina, Avicularoidea, Theraphosoidina, Araneomorphae, Entelegynae, Araneoidea, the RTA clade, Dionycha and the Lycosoidea. Alternatively, our results

  20. Spider phylogenomics: untangling the Spider Tree of Life

    Science.gov (United States)

    Garrison, Nicole L.; Rodriguez, Juanita; Agnarsson, Ingi; Coddington, Jonathan A.; Griswold, Charles E.; Hamilton, Christopher A.; Hedin, Marshal; Kocot, Kevin M.; Ledford, Joel M.

    2016-01-01

    Spiders (Order Araneae) are massively abundant generalist arthropod predators that are found in nearly every ecosystem on the planet and have persisted for over 380 million years. Spiders have long served as evolutionary models for studying complex mating and web spinning behaviors, key innovation and adaptive radiation hypotheses, and have been inspiration for important theories like sexual selection by female choice. Unfortunately, past major attempts to reconstruct spider phylogeny typically employing the “usual suspect” genes have been unable to produce a well-supported phylogenetic framework for the entire order. To further resolve spider evolutionary relationships we have assembled a transcriptome-based data set comprising 70 ingroup spider taxa. Using maximum likelihood and shortcut coalescence-based approaches, we analyze eight data sets, the largest of which contains 3,398 gene regions and 696,652 amino acid sites forming the largest phylogenomic analysis of spider relationships produced to date. Contrary to long held beliefs that the orb web is the crowning achievement of spider evolution, ancestral state reconstructions of web type support a phylogenetically ancient origin of the orb web, and diversification analyses show that the mostly ground-dwelling, web-less RTA clade diversified faster than orb weavers. Consistent with molecular dating estimates we report herein, this may reflect a major increase in biomass of non-flying insects during the Cretaceous Terrestrial Revolution 125–90 million years ago favoring diversification of spiders that feed on cursorial rather than flying prey. Our results also have major implications for our understanding of spider systematics. Phylogenomic analyses corroborate several well-accepted high level groupings: Opisthothele, Mygalomorphae, Atypoidina, Avicularoidea, Theraphosoidina, Araneomorphae, Entelegynae, Araneoidea, the RTA clade, Dionycha and the Lycosoidea. Alternatively, our results challenge the

  1. Approach and avoidance in fear of spiders

    NARCIS (Netherlands)

    Rinck, M.; Becker, E.S.

    2007-01-01

    We examined attitudes towards spiders by employing an Approach-Avoidance Task, in which participants respond to pictures by pulling a joystick towards themselves or by pushing it away from themselves. For spider fearfuls, this stimulus–response assignment is either compatible (push spiders away) or

  2. Spider and burnable poison rod combinations

    International Nuclear Information System (INIS)

    Edwards, G.T.; Schluderberg, D.C.

    1980-01-01

    An improved design of burnable poison rods and associated spiders used in fuel assemblies of pressurized water power reactor cores, is described. The rods are joined to the spider arms in a manner which is proof against the reactor core environment and yet allows the removal of the rods from the spider simply, swiftly and delicately. (U.K.)

  3. Phytoseiulus persimilis response to herbivore-induced plant volatiles as a function of mite-days.

    Science.gov (United States)

    Nachappa, Punya; Margolies, David C; Nechols, James R; Loughin, Thomas

    2006-01-01

    The predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae), uses plant volatiles (i.e., airborne chemicals) triggered by feeding of their herbivorous prey, Tetranychus urticae (Acari: Tetranychidae), to help locate prey patches. The olfactory response of P. persimilis to prey-infested plants varies in direct relation to the population growth pattern of T. urticae on the plant; P. persimilis responds to plants until the spider mite population feeding on a plant collapses, after which infested plants do not attract predators. It has been suggested that this represents an early enemy-free period for T. urticae before the next generation of females is produced. We hypothesize that the mechanism behind the diminished response of predators is due to extensive leaf damage caused by T. urticae feeding, which reduces the production of volatiles irrespective of the collapse of T. urticae population on the plant. To test this hypothesis we investigated how the response of P. persimilis to prey-infested plants is affected by: 1) initial density of T. urticae, 2) duration of infestation, and 3) corresponding leaf damage due to T. urticae feeding. Specifically, we assessed the response of P. persimilis to plants infested with two T. urticae densities (20 or 40 per plant) after 2, 4, 6, 8, 10, 12 or 14 days. We also measured leaf damage on these plants. We found that predator response to T. urticae-infested plants can be quantified as a function of mite-days, which is a cumulative measure of the standing adult female mite population sampled and summed over time. That is, response to volatiles increased with increasing numbers of T. urticae per plant or with the length of time plant was infested by T. urticae, at least as long at the leaves were green. Predatory mites were significantly attracted to plants that were infested for 2 days with only 20 spider mites. This suggests that the enemy-free period might only provide a limited window of opportunity for T. urticae

  4. Molecular phylogeny of moth-specialized spider sub-family Cyrtarachninae, which includes bolas spiders.

    Science.gov (United States)

    Tanikawa, Akio; Shinkai, Akira; Miyashita, Tadashi

    2014-11-01

    The evolutionary process of the unique web architectures of spiders of the sub-family Cyrtarachninae, which includes the triangular web weaver, bolas spider, and webless spider, is thought to be derived from reduction of orbicular 'spanning-thread webs' resembling ordinal orb webs. A molecular phylogenetic analysis was conducted to explore this hypothesis using orbicular web spiders Cyrtarachne, Paraplectana, Poecilopachys, triangular web spider Pasilobus, bolas spiders Ordgarius and Mastophora, and webless spider Celaenia. The phylogeny inferred from partial sequences of mt-COI, nuclear 18S-rRNA and 28S-rRNA showed that the common ancestor of these spiders diverged into two clades: a spanning-thread web clade and a bolas or webless clade. This finding suggests that the triangular web evolved by reduction of an orbicular spanning web, but that bolas spiders evolved in the early stage, which does not support the gradual web reduction hypothesis.

  5. Reconstitutable control rod spider assembly

    International Nuclear Information System (INIS)

    Shallenberger, J.M.; Ferian, S.J.

    1990-01-01

    A reconstitutable control rod/spider assembly includes a hollow connecting finger of the spider having a pair of opposing flat segments formed on the interior thereof and engaging a pair of opposing flat sectors formed on the exterior of a stem extending form the upper end of control rod. The stem also has an externally-threaded portion engaging a nut and a pilot aligning portion for the nut. The nut has a radially flexible and expandable thread-defining element captured in its bore. The segments and sectors allow the rod to be removed and reattached after turning through 180 0 to allow more even wear on the rod. (author)

  6. THE EXECUTION OF PLANNED DETOURS BY SPIDER-EATING PREDATORS

    Science.gov (United States)

    Cross, Fiona R.; Jackson, Robert R.

    2016-01-01

    Many spiders from the salticid subfamily Spartaeinae specialize at preying on other spiders and they adopt complex strategies when targeting these dangerous prey. We tested 15 of these spider-eating spartaeine species for the capacity to plan detours ahead of time. Each trial began with the test subject on top of a tower from which it could view two boxes: one containing prey and the other not containing prey. The distance between the tower and the boxes was too far to reach by leaping and the tower sat on a platform surrounded by water. As the species studied are known to avoid water, the only way they could reach the prey without getting wet was by taking one of two circuitous walkways from the platform: one leading to the prey (‘correct’) and one not leading to the prey (‘incorrect’). After leaving the tower, the test subject could not see the prey and sometimes it had to walk past the incorrect walkway before reaching the correct walkway. Yet all 15 species chose the correct walkway significantly more often than the incorrect walkway. We propose that these findings exemplify genuine cognition based on representation. PMID:26781057

  7. The effects of prey patchiness, predator aggregation, and mutual interference on the functional response of Phytoseiulus persimilis feeding on Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae)

    DEFF Research Database (Denmark)

    Nachman, Gösta

    2006-01-01

    The spatial distributions of two-spotted spider mites Tetranychus urticae and their natural enemy, the phytoseiid predator Phytoseiulus persimilis, were studied on six full-grown cucumber plants. Both mite species were very patchily distributed and P. persimilis tended to aggregate on leaves...

  8. PARASITIC MITES IN BACKYARD TURKEYS

    Directory of Open Access Journals (Sweden)

    Marco Antonio Camacho-Escobar

    2010-02-01

    Full Text Available To describe the parasitic mites in backyard turkeys, was did this work. The mites were obtain by hand for 30 backyard turkeys in Oaxaca’s Coast region, Mexico; the mites were mount in adhesive paper and wash with the 200X lent in a computer optical microscopy, the parasites size were determinate in the pictures obtained by the microscopy software, the images were sized using a specialist software for it, which relate the number of pixels in the picture with the size of the observation field. Were indentified the species Dermanyssus gallinae, Megninia ginglymura and Ornithonyssus sylviarum, the last two described for first time in backyard turkeys in Mexico. Â

  9. The Spider and the Fly

    Science.gov (United States)

    Mellinger, Keith E.; Viglione, Raymond

    2012-01-01

    The Spider and the Fly puzzle, originally attributed to the great puzzler Henry Ernest Dudeney, and now over 100 years old, asks for the shortest path between two points on a particular square prism. We explore a generalization, find that the original solution only holds in certain cases, and suggest how this discovery might be used in the…

  10. Predatory Mite Attraction to Herbivore-induced Plant Odors is not a Consequence of Attraction to Individual Herbivore-induced Plant Volatiles

    Science.gov (United States)

    De Bruijn, Paulien J. A.; Sabelis, Maurice W.

    2008-01-01

    Predatory mites locate herbivorous mites, their prey, by the aid of herbivore-induced plant volatiles (HIPV). These HIPV differ with plant and/or herbivore species, and it is not well understood how predators cope with this variation. We hypothesized that predators are attracted to specific compounds in HIPV, and that they can identify these compounds in odor mixtures not previously experienced. To test this, we assessed the olfactory response of Phytoseiulus persimilis, a predatory mite that preys on the highly polyphagous herbivore Tetranychus urticae. The responses of the predatory mite to a dilution series of each of 30 structurally different compounds were tested. They mites responded to most of these compounds, but usually in an aversive way. Individual HIPV were no more attractive (or less repellent) than out-group compounds, i.e., volatiles not induced in plants fed upon by spider-mites. Only three samples were significantly attractive to the mites: octan-1-ol, not involved in indirect defense, and cis-3-hexen-1-ol and methyl salicylate, which are both induced by herbivory, but not specific for the herbivore that infests the plant. Attraction to individual compounds was low compared to the full HIPV blend from Lima bean. These results indicate that individual HIPV have no a priori meaning to the mites. Hence, there is no reason why they could profit from an ability to identify individual compounds in odor mixtures. Subsequent experiments confirmed that naive predatory mites do not prefer tomato HIPV, which included the attractive compound methyl salicylate, over the odor of an uninfested bean. However, upon associating each of these odors with food over a period of 15 min, both are preferred. The memory to this association wanes within 24 hr. We conclude that P. persimilis possesses a limited ability to identify individual spider mite-induced plant volatiles in odor mixtures. We suggest that predatory mites instead learn to respond to prey

  11. Temperature-dependent, behavioural, and transcriptional variability of a tritrophic interaction consisting of bean, herbivorous mite, and predator.

    Science.gov (United States)

    Ozawa, Rika; Nishimura, Osamu; Yazawa, Shigenobu; Muroi, Atsushi; Takabayashi, Junji; Arimura, Gen-ichiro

    2012-11-01

    Different organisms compensate for, and adapt to, environmental changes in different ways. In this way, environmental changes affect animal-plant interactions. In this study, we assessed the effect of temperature on a tritrophic system of the lima bean, the herbivorous spider mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. In this system, the plant defends itself against T. urticae by emitting volatiles that attract P. persimilis. Over 20-40 °C, the emission of volatiles by infested plants and the subsequent attraction of P. persimilis peaked at 30 °C, but the number of eggs laid by T. urticae adults and the number of eggs consumed by P. persimilis peaked at 35 °C. This indicates that the spider mites and predatory mites performed best at a higher temperature than that at which most volatile attractants were produced. Our data from transcriptome pyrosequencing of the mites found that P. persimilis up-regulated gene families for heat shock proteins (HSPs) and ubiquitin-associated proteins, whereas T. urticae did not. RNA interference-mediated gene suppression in P. persimilis revealed differences in temperature responses. Predation on T. urticae eggs by P. persimilis that had been fed PpHsp70-1 dsRNA was low at 35 °C but not at 25 °C when PpHsp70-1 expression was very high. Overall, our molecular and behavioural approaches revealed that the mode and tolerance of lima bean, T. urticae and P. persimilis are distinctly affected by temperature variability, thereby making their tritrophic interactions temperature dependent. © 2012 Blackwell Publishing Ltd.

  12. Specialised use of working memory by Portia africana, a spider-eating salticid.

    Science.gov (United States)

    Cross, Fiona R; Jackson, Robert R

    2014-03-01

    Using expectancy-violation methods, we investigated the role of working memory in the predatory strategy of Portia africana, a salticid spider from Kenya that preys by preference on other spiders. One of this predator's tactics is to launch opportunistic leaping attacks on to other spiders in their webs. Focussing on this particular tactic, our experiments began with a test spider on a ramp facing a lure (dead prey spider mounted on a cork disc) that could be reached by leaping. After the test spider faced the lure for 30 s, we blocked the test spider's view of the lure by lowering an opaque shutter before the spider leapt. When the shutter was raised 90 s later, either the same lure came into view again (control) or a different lure came into view (experimental: different prey type in same orientation or same prey type in different orientation). We recorded attack frequency (number of test spiders that leapt at the lure) and attack latency (time elapsing between shutter being raised and spiders initiating a leap). Attack latencies in control trials were not significantly different from attack latencies in experimental trials, regardless of whether it was prey type or prey orientation that changed in the experimental trials. However, compared with test spiders in the no-change control trials, significantly fewer test spiders leapt when prey type changed. There was no significant effect on attack frequency when prey orientation changed. These findings suggest that this predator represents prey type independently of prey orientation.

  13. The evolution of sociality in spiders

    DEFF Research Database (Denmark)

    Lubin, Yael; Bilde, T.

    2007-01-01

    . Anelosimus (Theridiidae) C. Sociality in Spiders: An Evolutionary Dead End? V. Evolution and Maintenance of Sociality in Spiders: Relevant Models A. Kin Selection 1. Kin Recognition 2. Inbreeding and Kin Selection B. Multilevel Selection (Group Selection) C. Ecological Benefits D. Ecological Constraints E......I. Introducing Social Spiders II. Social and Subsocial Species: A Survey of Behavioral Traits III. Inbred Sociality in Spiders A. Cooperation Versus Competition: A Balancing Act B. Do Social Spiders Have Division of Labor? C. Colony Foundation: Propagule Dispersal Versus Fission D. Female......-Biased Colony Sex Ratios: Primary and Operational Sex Ratios E. Mating System: Inbreeding and Its Population-Genetic Consequences F. "Boom and Bust" Colony Dynamics IV. Phylogenetic Relationships Among Social Spider Species A. Common Features of Social Evolution B. Case Studies 1. Stegodyphus (Eresidae) 2...

  14. Radiation effect onto biodiversity of spiders

    International Nuclear Information System (INIS)

    Mehrabova, M.A.; Naghiyev, J.A; Huseynov, N.I; Topchiyeva, Sh.A.; Hasanov, N.H.

    2010-01-01

    At present time spiders are one of the considerably diverse groups of living organisms in fauna of Azerbayjan Republic. They play an important in environmental chain, being the main group of wild arthropodas in most biocoenoses. Therefore, it's not surprised that recently an increased interest has being observed to the study of spiders as indicators of environmental conditions. Spiders have been collected in polluted areas, their identification and sampling of soil, water and plants has been conducted. The degree of radionuclides' impact on the number and distribution of spiders and their venom in the observed zones of Azerbaijan has been revealed and preliminarily predicted. The number of the collected spiders equals to 292 which has been determined later at an electronic identifier Spinnen Mitteleuropas. The radionuclides in spiders have been determined at Canberra facility. Different natural radioactive elements were revealed in the investigated samples.

  15. House dust mite control measures for asthma

    DEFF Research Database (Denmark)

    Gøtzsche, Peter C.; Johansen, Helle Krogh

    2008-01-01

    BACKGROUND: The major allergen in house dust comes from mites. Chemical, physical and combined methods of reducing mite allergen levels are intended to reduce asthma symptoms in people who are sensitive to house dust mites. OBJECTIVES: To assess the effects of reducing exposure to house dust mite...... antigens in the homes of people with mite-sensitive asthma. SEARCH STRATEGY: PubMed and The Cochrane Library (last searches Nov 2007), reference lists. SELECTION CRITERIA: Randomised trials of mite control measures vs placebo or no treatment in people with asthma known to be sensitive to house dust mites......), the standardised mean difference was 0.00 (95% confidence interval (CI) -0.10 to 0.10). There were no statistically significant differences either in number of patients improved (relative risk 1.01, 95% CI 0.80 to 1.27), asthma symptom scores (standardised mean difference -0.04, 95% CI -0.15 to 0...

  16. Information use by the predatory mite Phytoseiulus persimilis (Acari: Phytoseiidae), a specialised natural enemy of herbivorous spider mites

    NARCIS (Netherlands)

    Boer, de J.G.; Dicke, M.

    2005-01-01

    Plants can respond to infestation by herbivores with the emission of specific herbivore-induced plant volatiles. Many carnivorous arthropods that feed on herbivorous prey use these volatiles to locate their prey. Despite the growing amount of research papers on the interactions in tritrophic

  17. Gamma irradiation as a quarantine treatment against mite (Tetranychidae) on cut flowers

    International Nuclear Information System (INIS)

    Zainon Othman; Mohd Ridzuan Ismail; Hamidah Sulaiman; Mohd Shamsudin Osman

    2000-01-01

    Cut flower, an important export commodity of Malaysia in international trade, is often subjected to infestation by various pests such as mites, scales and thrips. The use of low ionising radiation has been suggested as an alternative to methyl bromide fumigation, the current pest disinfestation treatment for cut flower but which is being phased out due to environmental concerns. The criterion for efficacy of radiation as a quarantine treatment will be the inability of treated mites to reproduce at a new location rather than causing immediate mortality. Irradiating red spider mite Tetranychus piercie at a dose of 300 and 400 Gy produced sterile female adults from irradiated protonymph and deutonymph respectively. A lower dose of 200 Gy induced sterility in female adults developed from the less immature stages of irradiated egg and larva. Deteriorating effects caused by irradiation treatment were reflected in immatures by their reduced emergence rate/mortality in subsequent developmental stages. A dose of 240 Gy prevented reproduction in female adult of T piercie by inducing sterility while a much higher dose of 5 kGy is required to produce instant mortality. Based on the results obtained gamma irradiation of dose range 300-400 Gy may be applied as a quarantine treatment against Tetranychus piercie. However, this dose range is only suitable for chrysanthemum (in 4% sucrose solution) but not roses, carnations and orchids which showed phytotoxic symptoms at dose range of 100-300 Gy

  18. House Dust Mite Respiratory Allergy

    DEFF Research Database (Denmark)

    Calderón, Moisés A; Kleine-Tebbe, Jörg; Linneberg, Allan

    2015-01-01

    Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence on the e......Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence...... not extend beyond the end of treatment. Finally, allergen immunotherapy has a poor but improving evidence base (notably on sublingual tablets) and its benefits last after treatment ends. This review identifies needs for deeper physician knowledge on the extent and impact of HDM allergy in respiratory disease...... and therapy of HDM respiratory allergy in practice....

  19. Antigenic relationship between the house dust mite Dermatophagoides farinae and the predacious mite Phytoseiulus persimilis.

    Science.gov (United States)

    Homma, R; Ando, T; Miyahara, A; Kimura, H; Ito, G; Uesato, N; Ino, Y; Iwaki, M

    1994-12-01

    We have examined the antigenic relationship between the house dust mite Dermatophagoides farinae and the predacious mite Phytoseiulus persimilis. Immunoblotting analysis demonstrated that there was a very weak antigenic cross-reactivity between these different suborder of mites but that this cross-reactivity was not attributed to D. farinaes major allergen's, Der fI and Der fII. These results suggest that P. persimilis might scarcely provoke allergic symptoms in patients sensitized to house dust mites.

  20. Science Education Resources on the Web--Spiders.

    Science.gov (United States)

    Thirunarayanan, M. O.

    1997-01-01

    Lists Web sites containing information on spiders and offers brief descriptions of the information available at those sites. The 11 sites provide information on taxonomy of spiders, anatomy, different ways spiders use silk, Internet mailing lists, folk literature and art, bibliographies, night collection, and spiders commonly found in the state of…

  1. Tangled in a sparse spider web

    DEFF Research Database (Denmark)

    Dimitrov, Dimitar Stefanov; Lopardo, Lara; Giribet, Gonzalo

    2012-01-01

    In order to study the tempo and the mode of spider orb web evolution and diversification, we conducted a phylogenetic analysis using six genetic markers along with a comprehensive taxon sample. The present analyses are the first to recover the monophyly of orb-weaving spiders based solely on DNA ...

  2. Verified spider bites in Oregon (USA) with the intent to assess hobo spider venom toxicity.

    Science.gov (United States)

    McKeown, Nathanael; Vetter, Richard S; Hendrickson, Robert G

    2014-06-01

    This study compiled 33 verified spider bites from the state of Oregon (USA). The initial goal was to amass a series of bites by the hobo spider to assess whether it possesses toxic venom, a supposition which is currently in a contested state. None of the 33 bites from several spider species developed significant medical symptoms nor did dermonecrosis occur. The most common biters were the yellow sac spider, Cheiracanthium mildei (N = 10) and orb-weavers of the genus Araneus (N = 6). There were 10 bites from three genera of funnel web spiders of the family Agelenidae including one hobo spider bite and one from the congeneric giant house spider which is readily confused as a hobo spider. The hobo spider bite resulted in pain, redness, twitching in the calf muscle and resolved in 12 h. Also generated from this study were possibly the first records of bites from spiders of the genera Callobius (Amaurobiidae) and Antrodiaetus (Antrodiaetidae), both with minor manifestations. Published by Elsevier Ltd.

  3. Maternal care and subsocial behaviour in spiders.

    Science.gov (United States)

    Yip, Eric C; Rayor, Linda S

    2014-05-01

    While most spiders are solitary and opportunistically cannibalistic, a variety of social organisations has evolved in a minority of spider species. One form of social organisation is subsociality, in which siblings remain together with their parent for some period of time but disperse prior to independent reproduction. We review the literature on subsocial and maternal behaviour in spiders to highlight areas in which subsocial spiders have informed our understanding of social evolution and to identify promising areas of future research. We show that subsocial behaviour has evolved independently at least 18 times in spiders, across a wide phylogenetic distribution. Subsocial behaviour is diverse in terms of the form of care provided by the mother, the duration of care and sibling association, the degree of interaction and cooperation among siblings, and the use of vibratory and chemical communication. Subsocial spiders are useful model organisms to study various topics in ecology, such as kin recognition and the evolution of cheating and its impact on societies. Further, why social behaviour evolved in some lineages and not others is currently a topic of debate in behavioural ecology, and we argue that spiders offer an opportunity to untangle the ecological causes of parental care, which forms the basis of many other animal societies. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

  4. The management of house dust mite allergies

    NARCIS (Netherlands)

    Bronswijk, van J.E.M.H.; Schober, G.; Kniest, F.M.

    1990-01-01

    A safe and practical home sanitation procedure for the removal of house dust mites (Dermatophagoides pteronyssinus) and their allergens is described. The severity of mite infestation was assessed with the use of the Acarex test, which measures the concentration of guanine in house dust, and all

  5. Respiratory allergy caused by house dust mites

    DEFF Research Database (Denmark)

    Calderón, Moisés A; Linneberg, Allan; Kleine-Tebbe, Jörg

    2015-01-01

    consequences in patients with respiratory allergic diseases. We investigate the epidemiology of HDM allergy to explore the interaction between mites and human subjects at the population, individual, and molecular levels. Core and recent publications were identified by using "house dust mite" as a key search...

  6. Domatia reduce larval cannibalism in predatory mites

    NARCIS (Netherlands)

    Ferreira, J.A.M.; Eshuis, B.; Janssen, A.; Sabelis, M.W.

    2008-01-01

    1. Acarodomatia are small structures on the underside of leaves of many plant species, which are mainly inhabited by carnivorous and fungivorous mites. 2. Domatia are thought to protect these mites against adverse environmental conditions and against predation. They are considered as an indirect

  7. Understanding Spider-Man: Your Everyday Superhero

    OpenAIRE

    Falk, Nicklas; Blomsterberg, Sofie Amalie; Suciu, Alice Sabrina; Pedersen, Mads Peter; Lucas, Vilhelm

    2014-01-01

    This project focuses on the understanding of Spider-Man, and the morals and ethics that lie behind the choices he makes. Through the Dimensions Philosophy & Science/Text & Sign, this understanding is concluded by looking at ethical theories and comic book analysis. Based on the Ultimate Spider-Man comic book series, the aim is to clarify who Spider-Man is and what causes him to act in certain ways; before and after his realization of power. Some theories used to investigate these area...

  8. Control of poultry red mites

    DEFF Research Database (Denmark)

    Kilpinen, Ole; Steenberg, Tove

    2008-01-01

    /carriers for various micro-organisms e.g. Salmonella. In SAFEHOUSE, an EU-project running from 2006-2009, partners from 11 European countries aim at developing new methods for prevention and control of Salmonella in egg production systems with particular focus on the transition to enriched cages in the EU. Enriched...... cages contain perches, nest boxes and dust bathing areas. This improves the welfare of the hens but also provides more hiding places for the PRM and may thus lead to increased ectoparasite problems. The approach taken against the PRM is to develop new control methods based on a combination of mite...

  9. The responses of cucumber plants subjected to different salinity or fertilizer concentrations and reproductive success of Tetranychus urticae mites on these plants.

    Science.gov (United States)

    Khodayari, Samira; Abedini, Fatemeh; Renault, David

    2018-05-01

    The plant stress hypothesis posits that a herbivore's reproductive success increases when it feeds on stressed plants, while the plant vigor hypothesis predicts that a herbivore preferentially feeds on more vigorous plants. We examined these opposing hypotheses by growing spider mites (Tetranychus urticae) on the leaves of stressed and healthy (vigorous) cucumber plants. Host plants were grown under controlled conditions at low, moderate, and high concentrations of NaCl (to induce salinity stress), at low, moderate, and high fertilizer concentrations (to support growth), and without these additions (control). The effects of these treatments were evaluated by measuring fresh and dry plant biomass, carotenoid and chlorophyll content, antioxidant enzyme activity, and concentrations of PO 4 3- , K + , and Na + in plant tissues. The addition of low concentrations of fertilizer increased dry mass, protein, and carotenoid content relative to controls, suggesting a beneficial effect on plants. The highest NaCl treatment (2560 mg L -1 ) resulted in increased Na + and protein content relative to control plants, as well as reduced PO 4 3- , K + , and chlorophyll levels and reduced catalase and ascorbate peroxidase enzyme activity levels. Analysis of life table data of T. urticae mites raised on leaves from the aforementioned plant groups showed the intrinsic rate of increase (r) for mites was 0.167 day -1 in control specimens, 0.125 day -1 for mites reared on plants treated with a moderate concentration of fertilizer (10 mL L -1 ), and was highest (0.241 day -1 ) on plants grown under moderate salinity conditions (1920 mg L -1 NaCl). Reproductive success of T. urticae did not differ on plants watered with a moderate concentration of NaCl or a high concentration of fertilizer. The moderately-stressed plants formed a favorable environment for the development and reproduction of spider mites, supporting the plant stress hypothesis.

  10. Non-webbuilding spiders: prey specialists or generalists?

    Science.gov (United States)

    Nentwig, Wolfgang

    1986-07-01

    Feeding experiments were performed with seven species of non-webbuilding spiders and a variety of prey taxa. Some species were generally polyphagous whereas other spiders restricted their prey to a few groups. At one end of the spectrum of prey specialization the thomisid Misumena vatia is limited to a few taxa of possible prey (Table 1). The literature of prey records of non-webbuilding spiders is reviewed (Table 2) with special emphasis on oligophagous or monophagous spiders. Monophagous spiders are generally rare and have specialized on only a few prey taxa: social insects (ants, bees, termites) and spiders.

  11. Almost a spider: a 305-million-year-old fossil arachnid and spider origins.

    Science.gov (United States)

    Garwood, Russell J; Dunlop, Jason A; Selden, Paul A; Spencer, Alan R T; Atwood, Robert C; Vo, Nghia T; Drakopoulos, Michael

    2016-03-30

    Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasierigen. et sp. nov. from the Late Carboniferous (Stephanian,ca 305-299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian-Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies. © 2016 The Authors.

  12. Edge effect on weevils and spiders

    OpenAIRE

    Horváth, R.; Magura, T.; Péter, G.; Tóthmérész, B.

    2002-01-01

    The edge effect on weevils and spiders was tested along oak forest – meadow transects using sweep-net samples at the Síkfökút Project in Hungary. For spiders the species richness was significantly higher in the forest edge than either in the meadow or the forest interior. For weevils the species richness of the forest edge was higher than that of the meadow, but the difference was not statistically significant whereas the species richness of the forest...

  13. Haematophagus Mites in Poultry Farms of Iran

    Directory of Open Access Journals (Sweden)

    S Rahbari

    2009-12-01

    Full Text Available Background: Blood sucking mites are important avian ectoparasites which being found on bird species worldwide. Their presence are problematic for the producers either through potential direct effects on weight gain, egg produc­tion, sperm production in roosters or as nuisance pests on worker handle hens and eggs. The aim of this study was pointing out of the status of haematophagus mites.Methods: Eight caged layer and four breeder flocks were visited, monitoring for the presence of chicken mites per­formed by removing and examining debris from poultry house, infested nesting material collected into zip lock plas­tic bags and at least 20 birds were also randomly selected to examine the presence of chicken mites. Mites obtained from each population were mounted in Hoyer,s medium on microscope slides and identified. All eight caged layer and four breeder flocks were inspected, which were infested with chicken blood feeding mites.Results: Massive infestations of Dermanyssus gallinae were common with huge numbers of parasites on birds, cages and the conveyor belts for egg. Only one farm from Mazandaran Province was infested to Ornithonyssus bursa.Conclusion: Dermanyssus gallinae was the most prevalent blood feeder mite in the breeder and caged layer flocks in Iran, while O. bursa was reported as a first record, which found only in a breeder flock in Mazanderan Province. It seems that its presence is limited into the area which affected by both warm and humid environmental conditions.

  14. Spiders do have melanin after all.

    Science.gov (United States)

    Hsiung, Bor-Kai; Blackledge, Todd A; Shawkey, Matthew D

    2015-11-01

    Melanin pigments are broadly distributed in nature - from bacteria to fungi to plants and animals. However, many previous attempts to identify melanins in spiders were unsuccessful, suggesting that these otherwise ubiquitous pigments were lost during spider evolution. Yet, spiders exhibit many dark colours similar to those produced by melanins in other organisms, and the low solubility of melanins makes isolation and characterization difficult. Therefore, whether melanins are truly absent or have simply not yet been detected is an open question. Raman spectroscopy provides a reliable way to detect melanins in situ, without the need for isolation. In this study, we document the presence of eumelanin in diverse species of spiders using confocal Raman microspectroscopy. Comparisons of spectra with theoretically calculated data falsify the previous hypothesis that dark colours are produced solely by ommochromes in spiders. Our data indicate that melanins are present in spiders and further supporting that they are present in most living organisms. © 2015. Published by The Company of Biologists Ltd.

  15. Genus-specificity of araneophagy of linyphiid spiders and spiders of other families (Arachnida, Araneae)

    NARCIS (Netherlands)

    Heuts, B.; Brunt, T.

    2009-01-01

    We found genus specificity of predation by spiders on other spiders in captivity which surpass them in body size (araneophagy). Adult specimens of three species of the linyphiid genus Walckenaeria which were successively tested for araneophagy (in the laboratory) in the order of first species

  16. Ant mimicry lessens predation on a North American jumping spider by larger salticid spiders.

    Science.gov (United States)

    Durkee, Caitlin A; Weiss, Martha R; Uma, Divya B

    2011-10-01

    Ant-like appearance (myrmecomorphy) has evolved >70 times in insects and spiders, accounting for >2,000 species of myrmecomorphic arthropods. Most myrmecomorphic spiders are considered to be Batesian mimics; that is, a palatable spider avoids predation through resemblance to an unpalatable ant-although this presumption has been tested in relatively few cases. Here we explicitly examined the extent to which Peckhamia picata (Salticidae), a North American ant-mimicking jumping spider, is protected from four species of jumping spider predators, relative to nonmimetic salticids and model ants. In addition, we conducted focused behavioral observations on one salticid predator, Thiodina puerpera, to determine the point at which the predators' behaviors toward model, mimic, and nonmimic diverge. We also examined the behaviors of Peckhamia in the presence of Thiodina. We found that mimetic jumping spiders were consumed less than a third as often as nonmimetic jumping spiders, suggesting that Peckhamia does indeed gain protection as a result of its resemblance to ants, and so can be considered a Batesian mimic. Furthermore, our focal predator did not consume any ant-mimicking spiders, and seemed to categorize Peckhamia with its model ant early in the hunting sequence. Such early determination of prey versus nonprey may be the result of speed-accuracy trade-offs in predator decision-making.

  17. Cognitive bias in spider-phobic children: Comparison of a pictorial and a linguistic spider Stroop.

    NARCIS (Netherlands)

    Kindt, M.; Brosschot, J.F.

    1999-01-01

    Examined the relation between spider fear in children and cognitive processing bias toward threatening information. It was investigated whether spider fear in children is related to a cognitive bias for threatening pictures and words. Pictorial and linguistic Stroop stimuli were administered to 28

  18. Effect Of Agrotechnical Measures And Varieties On Seasonal Dynamics Of Tetranychus Urticae Koch (Acari, Trombidiformes, Tetranychidae On High Tunnel-Cultivated Garden Strawberries

    Directory of Open Access Journals (Sweden)

    Salmane Ineta

    2015-04-01

    Full Text Available The aim of the present study was to determine the seasonal pattern of two-spotted spider mite Tetranychus urticae on strawberries cultivated in polythene-covered high tunnels in temperate climatic conditions. Various cultivars were used and the effect of modification of plant covering indices on abundance and incidence of these mites was also tested. The number of two-spotted spider mites was relatively low at the beginning of the vegetation season and started to increase when average air temperature rose above 20 to 25 °C. In the experiment two types of tunnels differing in additional plant cover were used. The maximum mite abundance did not significantly vary between varieties in tunnel 1 conditions, but it was significantly lower for variety 'Sonata' in tunnel 2 conditions. Mite numbers significantly declined after strawberry foliage mowing and removal of polythene cover. Mite development was prolonged in tunnel 1, where additional cover of plants was used and higher early season air temperature was recorded in comparison to tunnel 2. It was concluded that increase in early season temperature can increase two-spotted spider mite abundance and have a more negative effect on strawberry plants in respect of foliage damage by mites.

  19. Inactivation of dust mites, dust mite allergen, and mold from carpet.

    Science.gov (United States)

    Ong, Kee-Hean; Lewis, Roger D; Dixit, Anupma; MacDonald, Maureen; Yang, Mingan; Qian, Zhengmin

    2014-01-01

    Carpet is known to be a reservoir for biological contaminants, such as dust mites, dust mite allergen, and mold, if it is not kept clean. The accumulation of these contaminants in carpet might trigger allergies or asthma symptoms in both children and adults. The purpose of this study is to compare methods for removal of dust mites, dust mite allergens, and mold from carpet. Carpets were artificially worn to simulate 1 to 2 years of wear in a four-person household. The worn carpets were inoculated together with a common indoor mold (Cladosporium species) and house dust mites and incubated for 6 weeks to allow time for dust mite growth on the carpet. The carpets were randomly assigned to one of the four treatment groups. Available treatment regimens for controlling carpet contaminants were evaluated through a literature review and experimentation. Four moderately low-hazard, nondestructive methods were selected as treatments: vacuuming, steam-vapor, Neem oil (a natural tree extract), and benzalkonium chloride (a quaternary ammonium compound). Steam vapor treatment demonstrated the greatest dust mite population reduction (p 0.05) for both physical and chemical methods. The steam-vapor treatment effectively killed dust mites and denatured dust mite allergen in the laboratory environment.

  20. Male-male aggression peaks at intermediate relatedness in a social spider mite

    NARCIS (Netherlands)

    Sato, Y.; Egas, M.; Sabelis, M.W.; Mochizuki, A.

    2013-01-01

    Theory predicts that when individuals live in groups or colonies, male-male aggression peaks at intermediate levels of local average relatedness. Assuming that aggression is costly and directed toward nonrelatives and that competition for reproduction acts within the colony, benefits of aggressive

  1. Age-dependent male mating tactics in a spider mite — A life-history perspective

    NARCIS (Netherlands)

    Sato, Y.; Rühr, P.T.; Schmitz, H.; Egas, M.; Blanke, A.

    2016-01-01

    Males often fight with rival males for access to females. However, some males display nonfighting tactics such as sneaking, satellite behavior, or female mimicking. When these mating tactics comprise a conditional strategy, they are often thought to be explained by resource holding potential (RHP),

  2. Host plant preference of aphids, thrips and spider mites on GNA-expressing and control potatoes

    Czech Academy of Sciences Publication Activity Database

    Zemková-Rovenská, Gabriela; Zemek, Rostislav

    2006-01-01

    Roč. 34, č. 2 (2006), s. 139-148 ISSN 0334-2123 R&D Projects: GA AV ČR(CZ) IAA6007303 Institutional research plan: CEZ:AV0Z50070508 Keywords : insect-resistant transgenic plants * snowdrop (Galanthus nivalis) lectin * two-choice preference test Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 0.632, year: 2006

  3. A burst of ABC genes in the genome of the polyphagous spider mite Tetranychus urticae

    NARCIS (Netherlands)

    Dermauw, W.; Osborne, E.J.; Clark, R.M.; Grbić, M.; Tirry, L.; Van Leeuwen, T.

    2013-01-01

    Background: The ABC (ATP-binding cassette) gene superfamily is widespread across all living species. The majority of ABC genes encode ABC transporters, which are membrane-spanning proteins capable of transferring substrates across biological membranes by hydrolyzing ATP. Although ABC transporters

  4. Effect of pruning and trellising of tomatoes on red spider mite ...

    African Journals Online (AJOL)

    Key Words: Arthropod pest, Lycopersicon esculentum, Tetranychus evansi. RÉSUMÉ La petite araignée rouge, Tetranychus evansi Baker & Prichard accidentellement introduite en Afrique Australe vers 1980 est une peste relativement nouvelle pour la tomate (Lycopersicon esculentum) de l'Afrique. Depuis lors l'espèce ...

  5. Computer-assisted estimation of leaf damage caused by spider mites

    Czech Academy of Sciences Publication Activity Database

    Škaloudová, B.; Křivan, Vlastimil; Zemek, Rostislav

    2006-01-01

    Roč. 53, č. 2, (2006), s. 81-91 ISSN 0168-1699 R&D Projects: GA AV ČR(CZ) IAA6007303 Institutional research plan: CEZ:AV0Z50070508 Keywords : Tetranychus urticae * Acari * Tetranychidae Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 0.851, year: 2006

  6. Pest species diversity enhances control of spider mites and whiteflies by a generalist phytoseiid predator

    NARCIS (Netherlands)

    Messelink, G.J.; Maanen, van R.; Holstein-Saj, van R.; Sabelis, M.W.; Janssen, A.

    2010-01-01

    To test the hypothesis that pest species diversity enhances biological pest control with generalist predators, we studied the dynamics of three major pest species on greenhouse cucumber: Western flower thrips, Frankliniella occidentalis (Pergande), greenhouse whitefly, Trialeurodes vaporariorum

  7. A minute fossil phoretic mite recovered by phase-contrast X-ray computed tomography

    Science.gov (United States)

    Dunlop, Jason A.; Wirth, Stefan; Penney, David; McNeil, Andrew; Bradley, Robert S.; Withers, Philip J.; Preziosi, Richard F.

    2012-01-01

    High-resolution phase-contrast X-ray computed tomography (CT) reveals the phoretic deutonymph of a fossil astigmatid mite (Acariformes: Astigmata) attached to a spider's carapace (Araneae: Dysderidae) in Eocene (44–49 Myr ago) Baltic amber. Details of appendages and a sucker plate were resolved, and the resulting three-dimensional model demonstrates the potential of tomography to recover morphological characters of systematic significance from even the tiniest amber inclusions without the need for a synchrotron. Astigmatids have an extremely sparse palaeontological record. We confirm one of the few convincing fossils, potentially the oldest record of Histiostomatidae. At 176 µm long, we believe this to be the smallest arthropod in amber to be CT-scanned as a complete body fossil, extending the boundaries for what can be recovered using this technique. We also demonstrate a minimum age for the evolution of phoretic behaviour among their deutonymphs, an ecological trait used by extant species to disperse into favourable environments. The occurrence of the fossil on a spider is noteworthy, as modern histiostomatids tend to favour other arthropods as carriers. PMID:22072283

  8. A minute fossil phoretic mite recovered by phase-contrast X-ray computed tomography.

    Science.gov (United States)

    Dunlop, Jason A; Wirth, Stefan; Penney, David; McNeil, Andrew; Bradley, Robert S; Withers, Philip J; Preziosi, Richard F

    2012-06-23

    High-resolution phase-contrast X-ray computed tomography (CT) reveals the phoretic deutonymph of a fossil astigmatid mite (Acariformes: Astigmata) attached to a spider's carapace (Araneae: Dysderidae) in Eocene (44-49 Myr ago) Baltic amber. Details of appendages and a sucker plate were resolved, and the resulting three-dimensional model demonstrates the potential of tomography to recover morphological characters of systematic significance from even the tiniest amber inclusions without the need for a synchrotron. Astigmatids have an extremely sparse palaeontological record. We confirm one of the few convincing fossils, potentially the oldest record of Histiostomatidae. At 176 µm long, we believe this to be the smallest arthropod in amber to be CT-scanned as a complete body fossil, extending the boundaries for what can be recovered using this technique. We also demonstrate a minimum age for the evolution of phoretic behaviour among their deutonymphs, an ecological trait used by extant species to disperse into favourable environments. The occurrence of the fossil on a spider is noteworthy, as modern histiostomatids tend to favour other arthropods as carriers.

  9. Temperature preference and respiration of acaridid mites

    Czech Academy of Sciences Publication Activity Database

    Hubert, J.; Pekár, S.; Nesvorná, M.; Šustr, Vladimír

    2010-01-01

    Roč. 103, č. 6 (2010), s. 2249-2257 ISSN 0022-0493 Institutional research plan: CEZ:AV0Z60660521 Keywords : mites * temperature * acclimation Subject RIV: EH - Ecology, Behaviour Impact factor: 1.489, year: 2010

  10. Energetics, scaling and sexual size dimorphism of spiders.

    Science.gov (United States)

    Grossi, B; Canals, M

    2015-03-01

    The extreme sexual size dimorphism in spiders has motivated studies for many years. In many species the male can be very small relative to the female. There are several hypotheses trying to explain this fact, most of them emphasizing the role of energy in determining spider size. The aim of this paper is to review the role of energy in sexual size dimorphism of spiders, even for those spiders that do not necessarily live in high foliage, using physical and allometric principles. Here we propose that the cost of transport or equivalently energy expenditure and the speed are traits under selection pressure in male spiders, favoring those of smaller size to reduce travel costs. The morphology of the spiders responds to these selective forces depending upon the lifestyle of the spiders. Climbing and bridging spiders must overcome the force of gravity. If bridging allows faster dispersal, small males would have a selective advantage by enjoying more mating opportunities. In wandering spiders with low population density and as a consequence few male-male interactions, high speed and low energy expenditure or cost of transport should be favored by natural selection. Pendulum mechanics show the advantages of long legs in spiders and their relationship with high speed, even in climbing and bridging spiders. Thus small size, compensated by long legs should be the expected morphology for a fast and mobile male spider.

  11. Spider diffraction: a comparison of curved and straight legs

    International Nuclear Information System (INIS)

    Richter, J.L.

    1984-01-01

    It has been known for some time that, if curved legs rather than the usual straight ones are used in the spider that supports the secondary optics in certain telescopes, the visible diffraction effect is reduced. Fraunhofer theory is used to calculate the diffraction effects due to the curved leg spider. Calculated and photographic diffraction patterns are compared for straight and curved leg spiders

  12. Acute Generalized Exanthematous Pustulosis (AGEP Triggered by a Spider Bite

    Directory of Open Access Journals (Sweden)

    Michael Makris

    2009-01-01

    Discussion: A spider bite may represent a possible causative factor of AGEP. A spider's venom contains sphingomyelinase that stimulates the release of IL8 and GM-CSF, which are involved in AGEP pathogenesis. Whether or not the con-current use of antibiotics has an effect in AGEP appearance when combined with a spider's venom, cannot be excluded.

  13. Mites as selective fungal carriers in stored grain habitats.

    Science.gov (United States)

    Hubert, Jan; Stejskal, Václav; Kubátová, Alena; Munzbergová, Zuzana; Vánová, Marie; Zd'árková, Eva

    2003-01-01

    Mites are well documented as vectors of micromycetes in stored products. Since their vectoring capacity is low due to their small size, they can be serious vectors only where there is selective transfer of a high load of specific fungal species. Therefore the aim of our work was to find out whether the transfer of fungi is selective. Four kinds of stored seeds (wheat, poppy, lettuce, mustard) infested by storage mites were subjected to mycological analysis. We compared the spectrum of micromycete species isolated from different species of mites (Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, Caloglyphus rhizoglyphoides and Cheyletus malaccensis) and various kinds of stored seeds. Fungi were separately isolated from (a) the surface of mites, (b) the mites' digestive tract (= faeces), and (c) stored seeds and were then cultivated and determined. The fungal transport via mites is selective. This conclusion is supported by (i) lower numbers of isolated fungal species from mites than from seeds; (ii) lower Shannon-Weaver diversity index in the fungal communities isolated from mites than from seeds; (iii) significant effect of mites/seeds as environmental variables on fungal presence in a redundancy analysis (RDA); (iv) differences in composition of isolated fungi between mite species shown by RDA. The results of our work support the hypothesis that mite-fungal interactions are dependent on mite species. The fungi attractive to mites seem to be dispersed more than others. The selectivity of fungal transport via mites enhances their pest importance.

  14. Integration of multiple cues allows threat-sensitive anti-intraguild predator responses in predatory mites

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2013-01-01

    Intraguild (IG) prey is commonly confronted with multiple IG predator species. However, the IG predation (IGP) risk for prey is not only dependent on the predator species, but also on inherent (intraspecific) characteristics of a given IG predator such as its life-stage, sex or gravidity and the associated prey needs. Thus, IG prey should have evolved the ability to integrate multiple IG predator cues, which should allow both inter- and intraspecific threat-sensitive anti-predator responses. Using a guild of plant-inhabiting predatory mites sharing spider mites as prey, we evaluated the effects of single and combined cues (eggs and/or chemical traces left by a predator female on the substrate) of the low risk IG predator Neoseiulus californicus and the high risk IG predator Amblyseius andersoni on time, distance and path shape parameters of the larval IG prey Phytoseiulus persimilis. IG prey discriminated between traces of the low and high risk IG predator, with and without additional presence of their eggs, indicating interspecific threat-sensitivity. The behavioural changes were manifest in distance moved, activity and path shape of IG prey. The cue combination of traces and eggs of the IG predators conveyed other information than each cue alone, allowing intraspecific threat-sensitive responses by IG prey apparent in changed velocities and distances moved. We argue that graded responses to single and combined IG predator cues are adaptive due to minimization of acceptance errors in IG prey decision making. PMID:23750040

  15. Plant architecture and prey distribution influence foraging behavior of the predatory mite Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Gontijo, Lessando M; Nechols, James R; Margolies, David C; Cloyd, Raymond A

    2012-01-01

    The arrangement, number, and size of plant parts may influence predator foraging behavior, either directly, by altering the rate or pattern of predator movement, or, indirectly, by affecting the distribution and abundance of prey. We report on the effects of both plant architecture and prey distribution on foraging by the predatory mite, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae), on cucumber (Cucumis sativus L.). Plants differed in leaf number (2- or 6-leafed), and there were associated differences in leaf size, plant height, and relative proportions of plant parts; but all had the same total surface area. The prey, the twospotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae), were distributed either on the basal leaf or on all leaves. The effect of plant architecture on predator foraging behavior varied depending on prey distribution. The dimensions of individual plant parts affected time allocated to moving and feeding, but they did not appear to influence the frequency with which predators moved among different plant parts. Overall, P. persimilis moved less, and fed upon prey longer, on 6-leafed plants with prey on all leaves than on plants representing other treatment combinations. Our findings suggest that both plant architecture and pattern of prey distribution should be considered, along with other factors such as herbivore-induced plant volatiles, in augmentative biological control programs.

  16. Effects of Beauveria bassiana on predation and behavior of the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Wu, Shengyong; Xing, Zhenlong; Sun, Weinan; Xu, Xuenong; Meng, Ruixia; Lei, Zhongren

    2018-03-01

    Determination of intraguild interactions between entomopathogens and predators is important when attempting to use a combination of these two natural enemy groups for biological control of their shared arthropod pest species. This study assessed the effects of Beauveria bassiana on the predation and associated behavior of the predatory mite, Phytoseiulus persimilis, against Tetranychus urticae. The functional response tests showed that P. persimilis exhibited a Holling type II response on the spider mite, Tetranychus urticae, when treated with either a B. bassiana or Tween-80 suspension. There were no significant differences between the treatments in the number of T. urticae consumed. The laboratory choice test indicated that P. persimilis displayed a significant avoidance response to B. bassiana on bean leaves immediately following spray application. They also spent significantly longer time in self-grooming behavior on leaf disks sprayed with fungal conidia than on discs treated with Tween-80. There were no significant differences in the predation rates on T. urticae eggs between the different treatments. The potted plant investigations indicated that P. persimilis showed significant aversion behavior to the initial fungal spray, but gradually dispersed over the entire bean plants. Observations using scanning electron microscopy revealed that fungal conidia were attached to the body of P. persimilis after mounting the leaf disk treated with B. bassiana, which would account for its varied behavioral responses. Our study suggests that fungal spray did not affect the predation capability of P. persimilis and poses a negligible risk to their behavior. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Suppression of Plant Defenses by Herbivorous Mites Is Not Associated with Adaptation to Host Plants

    Directory of Open Access Journals (Sweden)

    Jéssica T. Paulo

    2018-06-01

    Full Text Available Some herbivores suppress plant defenses, which may be viewed as a result of the coevolutionary arms race between plants and herbivores. However, this ability is usually studied in a one-herbivore-one-plant system, which hampers comparative studies that could corroborate this hypothesis. Here, we extend this paradigm and ask whether the herbivorous spider-mite Tetranychus evansi, which suppresses the jasmonic-acid pathway in tomato plants, is also able to suppress defenses in other host plants at different phylogenetic distances from tomatoes. We test this using different plants from the Solanales order, namely tomato, jimsonweed, tobacco, and morning glory (three Solanaceae and one Convolvulaceae, and bean plants (Fabales. First, we compare the performance of T. evansi to that of the other two most-commonly found species of the same genus, T. urticae and T. ludeni, on several plants. We found that the performance of T. evansi is higher than that of the other species only on tomato plants. We then showed, by measuring trypsin inhibitor activity and life history traits of conspecific mites on either clean or pre-infested plants, that T. evansi can suppress plant defenses on all plants except tobacco. This study suggests that the suppression of plant defenses may occur on host plants other than those to which herbivores are adapted.

  18. Ontogenetic shifts in intraguild predation on thrips by phytoseiid mites: the relevance of body size and diet specialization.

    Science.gov (United States)

    Walzer, A; Paulus, H F; Schausberger, P

    2004-12-01

    In greenhouse agroecosystems, a guild of spider mite predators may consist of the oligophagous predatory mite Phytoseiulus persimilis Athias-Henriot, the polyphagous predatory mite Neoseiulus californicus McGregor (both Acari: Phytoseiidae) and the primarily herbivorous but facultatively predatory western flower thrips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae). Diet-specialization and the predator body size relative to prey are crucial factors in predation on F. occidentalis by P. persimilis and N. californicus. Here, it was tested whether the relevance of these factors changes during predator ontogeny. First, the predator (protonymphs and adult females of P. persimilis and N. californicus): prey (F. occidentalis first instars) body size ratios were measured. Second, the aggressiveness of P. persimilis and N. californicus towards F. occidentalis was assessed. Third, survival, development and oviposition of P. persimilis and N. californicus with F. occidentalis prey was determined. The body size ranking was P. persimilis females > N. californicus females > P. persimilis protonymphs > N. californicus protonymphs. Neoseiulus californicus females were the most aggressive predators, followed by highly aggressive N. californicus protonymphs and moderately aggressive P. persimilis protonymphs. Phytoseiulus persimilis females did not attack thrips. Frankliniella occidentalis larvae are an alternative prey for juvenile N. californicus and P. persimilis, enabling them to reach adulthood. Females of N. californicus but not P. persimilis sustained egg production with thrips prey. Within the guild studied here, N. californicus females are the most harmful predators for F. occidentalis larvae, followed by N. californicus and P. persimilis juveniles. Phytoseiulus persimilis females are harmless to F. occidentalis.

  19. Differential effects of plant species on a mite pest (Tetranychus utricae) and its predator (Phytoseiulus persimilis): implications for biological control.

    Science.gov (United States)

    Skirvin, D J; de Courcy Williams, M

    1999-06-01

    The influence of plant species on the population dynamics of the spider mite pest, Tetranychus urticae, and its predator, Phytoseiulus persimilis, was examined as a prerequisite to effective biological control on ornamental nursery stock. Experiments have been done to investigate how the development, fecundity and movement of T. urticae, and the movement of P. persimilis were affected by plant species. A novel experimental method, which incorporates plant structure, was used to investigate the functional response of P. persimilis. Development times for T. urticae were consistent with published data and did not differ with plant species in a biologically meaningful way. Plant species was shown to have a major influence on fecundity (P < 0.001) and movement of the pest mite (P < 0.01), but no influence on the movement of the predator. The movement of both pest and predator was shown to be related to the density of the adult pest mites on the plant (P < 0.001). Plant structure affected the functional response, particularly in relation to the ability of the predator to locate prey at low densities. The impact of these findings on the effective use of biological control on ornamental nursery stock is discussed.

  20. Genotypic variability and relationships between mite infestation levels, mite damage, grooming intensity, and removal of Varroa destructor mites in selected strains of worker honey bees (Apis mellifera L.).

    Science.gov (United States)

    Guzman-Novoa, Ernesto; Emsen, Berna; Unger, Peter; Espinosa-Montaño, Laura G; Petukhova, Tatiana

    2012-07-01

    The objective of this study was to demonstrate genotypic variability and analyze the relationships between the infestation levels of the parasitic mite Varroa destructor in honey bee (Apis mellifera) colonies, the rate of damage of fallen mites, and the intensity with which bees of different genotypes groom themselves to remove mites from their bodies. Sets of paired genotypes that are presumably susceptible and resistant to the varroa mite were compared at the colony level for number of mites falling on sticky papers and for proportion of damaged mites. They were also compared at the individual level for intensity of grooming and mite removal success. Bees from the "resistant" colonies had lower mite population rates (up to 15 fold) and higher percentages of damaged mites (up to 9 fold) than bees from the "susceptible" genotypes. At the individual level, bees from the "resistant" genotypes performed significantly more instances of intense grooming (up to 4 fold), and a significantly higher number of mites were dislodged from the bees' bodies by intense grooming than by light grooming (up to 7 fold) in all genotypes. The odds of mite removal were high and significant for all "resistant" genotypes when compared with the "susceptible" genotypes. The results of this study strongly suggest that grooming behavior and the intensity with which bees perform it, is an important component in the resistance of some honey bee genotypes to the growth of varroa mite populations. The implications of these results are discussed. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Remembering the object you fear: brain potentials during recognition of spiders in spider-fearful individuals.

    Science.gov (United States)

    Michalowski, Jaroslaw M; Weymar, Mathias; Hamm, Alfons O

    2014-01-01

    In the present study we investigated long-term memory for unpleasant, neutral and spider pictures in 15 spider-fearful and 15 non-fearful control individuals using behavioral and electrophysiological measures. During the initial (incidental) encoding, pictures were passively viewed in three separate blocks and were subsequently rated for valence and arousal. A recognition memory task was performed one week later in which old and new unpleasant, neutral and spider pictures were presented. Replicating previous results, we found enhanced memory performance and higher confidence ratings for unpleasant when compared to neutral materials in both animal fearful individuals and controls. When compared to controls high animal fearful individuals also showed a tendency towards better memory accuracy and significantly higher confidence during recognition of spider pictures, suggesting that memory of objects prompting specific fear is also facilitated in fearful individuals. In line, spider-fearful but not control participants responded with larger ERP positivity for correctly recognized old when compared to correctly rejected new spider pictures, thus showing the same effects in the neural signature of emotional memory for feared objects that were already discovered for other emotional materials. The increased fear memory for phobic materials observed in the present study in spider-fearful individuals might result in an enhanced fear response and reinforce negative beliefs aggravating anxiety symptomatology and hindering recovery.

  2. Flee or fight: ontogenetic changes in the behavior of cobweb spiders in encounters with spider-hunting wasps.

    Science.gov (United States)

    Uma, Divya B; Weiss, Martha R

    2012-12-01

    An animal's body size plays a predominant role in shaping its interspecific interactions, and, in encounters between two predators, often determines which shall be predator and which shall be prey. Spiders are top predators of insects, yet can fall prey to mud-dauber wasps that provision their larval nests with paralyzed spiders. Here we examined predator-prey interactions between Chalybion californicum (Saussure) (Sphecidae), a mud-dauber wasp, and Parasteatoda tepidariorum C. L. Koch (Theridiidae), a cobweb spider. We examined whether a spider's size influences its response to an attacking wasp, and report a size-dependent change in spider behavior: small-sized spiders fled, whereas medium- and large-sized spiders fought in response to wasp attacks. From the wasps' perspective, we examined whether spider size influences a wasp's hunting behavior and capture success. We found that wasps commonly approached small spiders, but were much less likely to approach medium and large spiders. However, wasp capture success did not vary with spider size. We also report a strategy used by Chalybion wasps toward cobweb spiders that is consistent with an interpretation of aggressive mimicry.

  3. Wheat curl mite and dry bulb mite: untangling a taxonomic conundrum through a multidisciplinary approach

    Science.gov (United States)

    The taxonomy of two economically important eriophyoid species, Aceria tosichella (wheat curl mite, WCM) and A. tulipae (dry bulb mite, DBM), was confounded in the world literature until the late 20th century due to their morphological similarity and ambiguous data from plant-transfer and virus-trans...

  4. Life cycle and reproduction of house-dust mites: environmental factors influencing mite populations.

    Science.gov (United States)

    Hart, B J

    1998-01-01

    An understanding of the life cycle of house-dust mites, as well as environmental factors influencing mite populations, can be exploited in mite control. The most important limiting factor for house-dust-mite populations is air humidity. House-dust mites osmoregulate through the cuticle and therefore require a high ambient air humidity to prevent excessive water loss. In addition, the supracoxal glands actively take up ambient water vapour, and the protonynph stage of the life cycle is resistant to desiccation. Larger house-dust-mite populations are found when the absolute indoor air humidity is above 7 g/kg (45% relative humidity at 20 degrees C). Consequently, ventilation by air-conditioning systems is being developed as a means of control. A number of other aspects of the domestic environment are also being manipulated in an integrated approach to render the habitat less suitable for mites. The potential exists for developing models for house-dust mite populations, environmental characteristics, and the effects of various approaches to control.

  5. Hygienic Activity Toward Varroa Mites in Capped Brood is not Dependent on Mite Reproductive Status

    Science.gov (United States)

    - The varroa resistance of bees selectively bred for high levels of varroa sensitive hygiene (VSH) is characterized by a reduction of (1) the mite infestation rate (Harris 2007 J. Apic. Res. / Bee World 46: 134-139) and (2) the percentage of fertile mites (Harris and Harbo 1999 J. Econ. Entomol. 92:...

  6. Fish predation by semi-aquatic spiders: a global pattern.

    Directory of Open Access Journals (Sweden)

    Martin Nyffeler

    Full Text Available More than 80 incidences of fish predation by semi-aquatic spiders--observed at the fringes of shallow freshwater streams, rivers, lakes, ponds, swamps, and fens--are reviewed. We provide evidence that fish predation by semi-aquatic spiders is geographically widespread, occurring on all continents except Antarctica. Fish predation by spiders appears to be more common in warmer areas between 40° S and 40° N. The fish captured by spiders, usually ranging from 2-6 cm in length, are among the most common fish taxa occurring in their respective geographic area (e.g., mosquitofish [Gambusia spp.] in the southeastern USA, fish of the order Characiformes in the Neotropics, killifish [Aphyosemion spp.] in Central and West Africa, as well as Australian native fish of the genera Galaxias, Melanotaenia, and Pseudomugil. Naturally occurring fish predation has been witnessed in more than a dozen spider species from the superfamily Lycosoidea (families Pisauridae, Trechaleidae, and Lycosidae, in two species of the superfamily Ctenoidea (family Ctenidae, and in one species of the superfamily Corinnoidea (family Liocranidae. The majority of reports on fish predation by spiders referred to pisaurid spiders of the genera Dolomedes and Nilus (>75% of observed incidences. There is laboratory evidence that spiders from several more families (e.g., the water spider Argyroneta aquatica [Cybaeidae], the intertidal spider Desis marina [Desidae], and the 'swimming' huntsman spider Heteropoda natans [Sparassidae] predate fish as well. Our finding of such a large diversity of spider families being engaged in fish predation is novel. Semi-aquatic spiders captured fish whose body length exceeded the spiders' body length (the captured fish being, on average, 2.2 times as long as the spiders. Evidence suggests that fish prey might be an occasional prey item of substantial nutritional importance.

  7. Fish predation by semi-aquatic spiders: a global pattern.

    Science.gov (United States)

    Nyffeler, Martin; Pusey, Bradley J

    2014-01-01

    More than 80 incidences of fish predation by semi-aquatic spiders--observed at the fringes of shallow freshwater streams, rivers, lakes, ponds, swamps, and fens--are reviewed. We provide evidence that fish predation by semi-aquatic spiders is geographically widespread, occurring on all continents except Antarctica. Fish predation by spiders appears to be more common in warmer areas between 40° S and 40° N. The fish captured by spiders, usually ranging from 2-6 cm in length, are among the most common fish taxa occurring in their respective geographic area (e.g., mosquitofish [Gambusia spp.] in the southeastern USA, fish of the order Characiformes in the Neotropics, killifish [Aphyosemion spp.] in Central and West Africa, as well as Australian native fish of the genera Galaxias, Melanotaenia, and Pseudomugil). Naturally occurring fish predation has been witnessed in more than a dozen spider species from the superfamily Lycosoidea (families Pisauridae, Trechaleidae, and Lycosidae), in two species of the superfamily Ctenoidea (family Ctenidae), and in one species of the superfamily Corinnoidea (family Liocranidae). The majority of reports on fish predation by spiders referred to pisaurid spiders of the genera Dolomedes and Nilus (>75% of observed incidences). There is laboratory evidence that spiders from several more families (e.g., the water spider Argyroneta aquatica [Cybaeidae], the intertidal spider Desis marina [Desidae], and the 'swimming' huntsman spider Heteropoda natans [Sparassidae]) predate fish as well. Our finding of such a large diversity of spider families being engaged in fish predation is novel. Semi-aquatic spiders captured fish whose body length exceeded the spiders' body length (the captured fish being, on average, 2.2 times as long as the spiders). Evidence suggests that fish prey might be an occasional prey item of substantial nutritional importance.

  8. Inbreeding avoidance in spiders: evidence for rescue effect in fecundity of female spiders with outbreeding opportunity

    DEFF Research Database (Denmark)

    Bilde, T.; Maklakov, A.A.; Schilling, Nadia

    2007-01-01

    avoidance can be because of low risk of inbreeding, variation in tolerance to inbreeding or high costs of outbreeding. We examined the relationship between inbreeding depression and inbreeding avoidance adaptations under two levels of inbreeding in the spider Oedothorax apicatus, asking whether preference...... for unrelated sperm via pre- and/or post-copulatory mechanisms could restore female fitness when inbreeding depression increases. Using inbred isofemale lines we provided female spiders with one or two male spiders of different relatedness in five combinations: one male sib; one male nonsib; two male sibs; two...

  9. Origin and higher-level diversification of acariform mites - evidence from nuclear ribosomal genes, extensive taxon sampling, and secondary structure alignment.

    Science.gov (United States)

    Pepato, A R; Klimov, P B

    2015-09-02

    Acariformes is the most species-rich and morphologically diverse radiation of chelicerate arthropods, known from the oldest terrestrial ecosystems. It is also a key lineage in understanding the evolution of this group, with the most vexing question whether mites, or Acari (Parasitiformes and Acariformes) is monophyletic. Previous molecular studies recovered Acari either as monophyletic or non-monophyletic, albeit with a limited taxon sampling. Similarly, relationships between basal acariform groups (include little-known, deep-soil 'endeostigmatan' mites) and major lineages of Acariformes (Sarcoptiformes, Prostigmata) are virtually unknown. We infer phylogeny of chelicerate arthropods, using a large and representative dataset, comprising all main in- and outgroups (228 taxa). Basal diversity of Acariformes is particularly well sampled. With this dataset, we conduct a series of phylogenetically explicit tests of chelicerate and acariform relationships and present a phylogenetic framework for internal relationships of acariform mites. Our molecular data strongly support a diphyletic Acari, with Acariformes as the sister group to Solifugae (PP =1.0; BP = 100), the so called Poecilophysidea. Among Acariformes, some representatives of the basal group Endeostigmata (mainly deep-soil mites) were recovered as sister-groups to the remaining Acariformes (i. e., Trombidiformes + and most of Sarcoptiformes). Desmonomatan oribatid mites (soil and litter mites) were recovered as the monophyletic sister group of Astigmata (e. g., stored product mites, house dust mites, mange mites, feather and fur mites). Trombidiformes (Sphaerolichida + Prostigmata) is strongly supported (PP =1.0; BP = 98-100). Labidostommatina was inferred as the basal lineage of Prostigmata. Eleutherengona (e. g., spider mites) and Parasitengona (e. g., chiggers, fresh water mites) were recovered as monophyletic. By contrast, Eupodina (e. g., snout mites and relatives) was not. Marine mites (Halacaridae) were

  10. Optically probing torsional superelasticity in spider silks

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P. [Department of Physical Sciences, IISER Mohali, Sector 81, Manauli, Mohali 140306 (India)

    2013-11-11

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10{sup 2−3} rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices.

  11. SPIDER: A Framework for Understanding Driver Distraction.

    Science.gov (United States)

    Strayer, David L; Fisher, Donald L

    2016-02-01

    The objective was to identify key cognitive processes that are impaired when drivers divert attention from driving. Driver distraction is increasingly recognized as a significant source of injuries and fatalities on the roadway. A "SPIDER" model is developed that identifies key cognitive processes that are impaired when drivers divert attention from driving. SPIDER is an acronym standing for scanning, predicting, identifying, decision making, and executing a response. When drivers engage in secondary activities unrelated to the task of driving, SPIDER-related processes are impaired, situation awareness is degraded, and the ability to safely operate a motor vehicle may be compromised. The pattern of interference helps to illuminate the sources of driver distraction and may help guide the integration of new technology into the automobile. © 2015, Human Factors and Ergonomics Society.

  12. Optically probing torsional superelasticity in spider silks

    International Nuclear Information System (INIS)

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P.

    2013-01-01

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10 2−3 rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices

  13. Edge effect on weevils and spiders

    Directory of Open Access Journals (Sweden)

    R. Horváth

    2002-05-01

    Full Text Available The edge effect on weevils and spiders was tested along oak forest – meadow transects using sweep-net samples at the Síkfökút Project in Hungary. For spiders the species richness was significantly higher in the forest edge than either in the meadow or the forest interior. For weevils the species richness of the forest edge was higher than that of the meadow, but the difference was not statistically significant whereas the species richness of the forest interior was significantly lower than that of the forest edge and the meadow. The composition of the spider assemblage of the edge was more similar to the forest, while the composition of weevils in the edge was more similar to the meadow. Our results based on two invertebrate groups operating on different trophic levels suggest that there is a significant edge effect for the studied taxa resulting in higher species richness in the edge.

  14. Haematophagus Mites in Poultry Farms of Iran

    Directory of Open Access Journals (Sweden)

    S Rahbari

    2009-12-01

    Full Text Available Background: Blood sucking mites are important avian ectoparasites which being found on bird species worldwide. Their presence are problematic for the producers either through potential direct effects on weight gain, egg produc­tion, sperm production in roosters or as nuisance pests on worker handle hens and eggs. The aim of this study was pointing out of the status of haematophagus mites."nMethods: Eight caged layer and four breeder flocks were visited, monitoring for the presence of chicken mites per­formed by removing and examining debris from poultry house, infested nesting material collected into zip lock plas­tic bags and at least 20 birds were also randomly selected to examine the presence of chicken mites. Mites obtained from each population were mounted in Hoyer,s medium on microscope slides and identified. All eight caged layer and four breeder flocks were inspected, which were infested with chicken blood feeding mites."nResults: Massive infestations of Dermanyssus gallinae were common with huge numbers of parasites on birds, cages and the conveyor belts for egg. Only one farm from Mazandaran Province was infested to Ornithonyssus bursa."nConclusion: Dermanyssus gallinae was the most prevalent blood feeder mite in the breeder and caged layer flocks in Iran, while O. bursa was reported as a first record, which found only in a breeder flock in Mazanderan Province. It seems that its presence is limited into the area which affected by both warm and humid environmental conditions.  Keywords: Dermanyssus gallinae, Ornithonyssus bursa, Poultry, Iran

  15. Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

    Energy Technology Data Exchange (ETDEWEB)

    Akamatsu, Fumikazu, E-mail: f-akamt55@pwri.go.jp [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Toda, Hideshige [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

    2011-05-15

    Stable nitrogen isotopic composition ({delta}{sup 15}N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in {delta}{sup 15}N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider {delta}{sup 15}N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: > {delta}{sup 15}N of aquatic insects increases downstream with anthropogenic nitrogen inputs. > {delta}{sup 15}N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. > The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

  16. Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

    International Nuclear Information System (INIS)

    Akamatsu, Fumikazu; Toda, Hideshige

    2011-01-01

    Stable nitrogen isotopic composition (δ 15 N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ 15 N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ 15 N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: → δ 15 N of aquatic insects increases downstream with anthropogenic nitrogen inputs. → δ 15 N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. → The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

  17. Disentangling the phylogenetic and ecological components of spider phenotypic variation.

    Science.gov (United States)

    Gonçalves-Souza, Thiago; Diniz-Filho, José Alexandre Felizola; Romero, Gustavo Quevedo

    2014-01-01

    An understanding of how the degree of phylogenetic relatedness influences the ecological similarity among species is crucial to inferring the mechanisms governing the assembly of communities. We evaluated the relative importance of spider phylogenetic relationships and ecological niche (plant morphological variables) to the variation in spider body size and shape by comparing spiders at different scales: (i) between bromeliads and dicot plants (i.e., habitat scale) and (ii) among bromeliads with distinct architectural features (i.e., microhabitat scale). We partitioned the interspecific variation in body size and shape into phylogenetic (that express trait values as expected by phylogenetic relationships among species) and ecological components (that express trait values independent of phylogenetic relationships). At the habitat scale, bromeliad spiders were larger and flatter than spiders associated with the surrounding dicots. At this scale, plant morphology sorted out close related spiders. Our results showed that spider flatness is phylogenetically clustered at the habitat scale, whereas it is phylogenetically overdispersed at the microhabitat scale, although phylogenic signal is present in both scales. Taken together, these results suggest that whereas at the habitat scale selective colonization affect spider body size and shape, at fine scales both selective colonization and adaptive evolution determine spider body shape. By partitioning the phylogenetic and ecological components of phenotypic variation, we were able to disentangle the evolutionary history of distinct spider traits and show that plant architecture plays a role in the evolution of spider body size and shape. We also discussed the relevance in considering multiple scales when studying phylogenetic community structure.

  18. Uncovering the structure-function relationship in spider silk

    Science.gov (United States)

    Yarger, Jeffery L.; Cherry, Brian R.; van der Vaart, Arjan

    2018-03-01

    All spiders produce protein-based biopolymer fibres that we call silk. The most studied of these silks is spider dragline silk, which is very tough and relatively abundant compared with other types of spider silks. Considerable research has been devoted to understanding the relationship between the molecular structure and mechanical properties of spider dragline silks. In this Review, we overview experimental and computational studies that have provided a wealth of detail at the molecular level on the highly conserved repetitive core and terminal regions of spider dragline silk. We also discuss the role of the nanocrystalline β-sheets and amorphous regions in determining the properties of spider silk fibres, endowing them with strength and elasticity. Additionally, we outline imaging techniques and modelling studies that elucidate the importance of the hierarchical structure of silk fibres at the molecular level. These insights into structure-function relationships can guide the reverse engineering of spider silk to enable the production of superior synthetic fibres.

  19. Checklist of spider fauna of FR Peshawar, FATA, Pakistan

    Directory of Open Access Journals (Sweden)

    F. Perveen

    2012-03-01

    Full Text Available The spiders are known as poisonous arthropods, but they also act as the predator or biological pests control agent. Their 23 species belonging to 15 genera and 09 families were reported during 2009-2010 from FR Peshawar, FATA, Pakistan. The reported families Clubionidae, Scytodidae and Sprassidae covered each 4%, Araneidae, Gnaphosidae, Pholicidae and Salticidae each 9%, Thomisidae 13% and Lycosidae 43% biodiversity of spiders of FATA. However, the largest spider collected was huntsman, Isopoda tuhodnigra (Barrion with total body length 15.80+-0.83 mm. Moreover, the smallest spider was wolf spider, Pardosa birmanica (Simon with total body length 4.20+-1.30 mm. Further, the crab spiders, Thomisus pugilis (Stoliczka, T. spectabilis (Doleschall and Diaea evanida (Thorell were the most colorful species belonging to family Thomisidae. A detail study is required for further exploration of spider fauna of FATA.

  20. Recombinant DNA production of spider silk proteins.

    Science.gov (United States)

    Tokareva, Olena; Michalczechen-Lacerda, Valquíria A; Rech, Elíbio L; Kaplan, David L

    2013-11-01

    Spider dragline silk is considered to be the toughest biopolymer on Earth due to an extraordinary combination of strength and elasticity. Moreover, silks are biocompatible and biodegradable protein-based materials. Recent advances in genetic engineering make it possible to produce recombinant silks in heterologous hosts, opening up opportunities for large-scale production of recombinant silks for various biomedical and material science applications. We review the current strategies to produce recombinant spider silks. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  1. Programming spiders, bots, and aggregators in Java

    CERN Document Server

    Heaton, Jeff

    2006-01-01

    The content and services available on the web continue to be accessed mostly through direct human control. But this is changing. Increasingly, users rely on automated agents that save them time and effort by programmatically retrieving content, performing complex interactions, and aggregating data from diverse sources. Programming Spiders, Bots, and Aggregators in Java teaches you how to build and deploy a wide variety of these agents-from single-purpose bots to exploratory spiders to aggregators that present a unified view of information from multiple user accounts. You will quickly build on

  2. Pathogenecity of Beauveria bassiana and Metarhizium anisopliae ...

    African Journals Online (AJOL)

    two spotted spider mites, Tetranychus urticae, effect of temperature on virulence, as well as ... It has become a big challenge to maintain quality of products and compete in ... Data were collected on the number of hatched and un-hatched eggs.

  3. Hot-spot application of biocontrol agents to replace pesticides in large scale commercial rose farms in Kenya

    DEFF Research Database (Denmark)

    Gacheri, Catherine; Kigen, Thomas; Sigsgaard, Lene

    2015-01-01

    Rose (Rosa hybrida L.) is the most important ornamental crop in Kenya, with huge investments in pest management. We provide the first full-scale, replicated experiment comparing cost and yield of conventional two-spotted spider mite (Tetranychus urticae Koch) control with hot-spot applications of...

  4. Lima bean – lady beetle interactions: hooked trichomes affect survival of Stethorus punctillum larvae

    Science.gov (United States)

    We tested the hypothesis that Lima bean Phaseolus lunatus L. (Henderson cultivar) trichome density affects the survival of the acariphagous lady beetle Stethorus punctillum Weise. When isolated throughout larval development, 10% or less of S. punctillum larvae reared on two-spotted spider mite Tetr...

  5. Pathogenecity of Beauveria bassiana and Metarhizium anisopliae ...

    African Journals Online (AJOL)

    emulsifiable formulation on two-spotted spider mite, T. urticae. Weibin and. Mingguang (2004) found that both B. bassiana and Paecilomyces fumosoroseus infections decreased the hatch rates of Tetranychus cinnanarinus eggs and the higher the conidial concentrations resulted in greater reduction in the hatch rates.

  6. Functional characterization of glutathione S-transferases associated with insecticide resistance in Tetranychus urticae

    NARCIS (Netherlands)

    Pavlidi, N.; Tseliou, V.; Riga, M.; Nauen, R.; Van Leeuwen, T.; Labrou, N.E.; Vontas, J.

    2015-01-01

    The two-spotted spider mite Tetranychus urticae is one of the most important agricultural pests world-wide. It is extremely polyphagous and develops resistance to acaricides. The overexpression of several glutathione S-transferases (GSTs) has been associated with insecticide resistance. Here, we

  7. Scavenging by spiders (Araneae) and its relationship to pest management of the brown recluse spider.

    Science.gov (United States)

    Vetter, Richard S

    2011-06-01

    Experiments reported in Sandidge (2003; Nature 426: 30) indicated that the brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, preferred to scavenge dead prey over live prey and that the spiders were not detrimentally affected when fed insecticide-killed crickets. Extrapolations made in subsequent media coverage disseminating the results of this research made counter-intuitive statements that pesticide treatment in houses would increase brown recluse populations in homes. This information was presented as if the scavenging behavior was specialized in the brown recluse; however, it was more likely that this behavior has not been well studied in other species. To provide a comparison, the current laboratory study examined the likelihood of non-Loxosceles spiders to scavenge dead prey. Of 100 non-Loxosceles spiders that were tested (from 11 families, 24 genera, and at least 29 species from a variety of spider hunting guilds), 99 scavenged dead crickets when offered in petri dishes. Some of the spiders were webspinners in which real-world scavenging of dead prey is virtually impossible, yet they scavenge when given the opportunity. Therefore, scavenging is a flexible opportunistic predatory behavior that is spread across a variety of taxa and is not a unique behavior in brown recluses. These findings are discussed in relation to pest management practices.

  8. [Investigation of Acaroid mites breeding in stored dry fruits].

    Science.gov (United States)

    Tao, Ning; Zhan, Xiao-dong; Sun, En-tao; Li, Chao-pin

    2015-12-01

    To study the species and density of Acaroid mites breeding in stored dry fruits. The samples from the dried fruit stores and warehouses were collected, and the mites breeding in them were separated, then the slides with mites were prepared and observed by a light microscope for species identification and counting. The indexes such as the breeding density, species richness index, diversity index and evenness index were calculated. Totally 12 species of Acaroid mites belonging to 6 families and 10 genera were obtained from the total 49 samples. The dominant mite species were Carpoglyphus lactis, Tyrophagus putrescentiae, Acarus siro, and Caloglyphus berlesei. The breeding densities of mites in longans, filberts and plum candies were 79.78, 48.91, 35.73 mites/g, respectively, which were higher than those in other dry fruits. The seasonal variation experiment of mites found that the average breeding density of acaroid mites was higher in July and October, the richness index and diversity index reached the highest value in July, and the evenness index was higher in January and April. The observation of the growth and decline of Acaroid mites under the artificial condition found the number of Caloglyphus berlesei declined sharply and Tyrophagus putrescentiae first increased and then decreased. The pollution of Acaroid mites is serious in the stored dried fruits, for which the positive prevention and control measures to the mite breeding should be taken to reduce the harm.

  9. Does the removal of mite-infested brood facilitate grooming?

    Science.gov (United States)

    The relationship between the removal of mite-infested brood and mite drop was compared using Russian (RHB, n = 9) and Italian (IHB, n = 9) honey bee colonies. A cloake board was used to isolate test brood frame on the top hive body and the metal sheet served as a varroa trap. Inoculum mites were col...

  10. Plant-herbivore interaction: dissection of the cellular pattern of Tetranychus urticae feeding on the host plant

    Directory of Open Access Journals (Sweden)

    Nicolas Bensoussan

    2016-07-01

    Full Text Available The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae, is one of the most polyphagous herbivores feeding on cell contents of over 1,100 plant species including more than 150 crops. It is being established as a model for chelicerate herbivores with tools that enable tracking of reciprocal responses in plant-spider mite interactions. However, despite their important pest status and a growing understanding of the molecular basis of interactions with plant hosts, knowledge of the way mites interface with the plant while feeding and the plant damage directly inflicted by mites is lacking. Here, utilizing histology and microscopy methods, we uncovered several key features of T. urticae feeding. By following the stylet path within the plant tissue, we determined that the stylet penetrates the leaf either in between epidermal pavement cells or through a stomatal opening, without damaging the epidermal cellular layer. Our recordings of mite feeding established that duration of the feeding event ranges from several minutes to more than half an hour, during which time mites consume a single mesophyll cell in a pattern that is common to both bean and Arabidopsis plant hosts. In addition, this study determined that leaf chlorotic spots, a common symptom of mite herbivory, do not form as an immediate consequence of mite feeding. Our results establish a cellular context for the plant-spider mite interaction that will support our understanding of the molecular mechanisms and cell signaling associated with spider mite feeding.

  11. Spider and burnable poison rod combinations

    International Nuclear Information System (INIS)

    Walton, L.A.

    1980-01-01

    A description is given of an improved design of burnable poison rods and their associated spiders used in the fuel assemblies of pressurized water power reactor cores which allows the rods to be installed and removed more quickly, simply and gently than in previously described systems. (U.K.)

  12. Silk Spinning in Silkworms and Spiders.

    Science.gov (United States)

    Andersson, Marlene; Johansson, Jan; Rising, Anna

    2016-08-09

    Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and spiders, with the aim of identifying features that are important for fiber formation. Although spiders and silkworms are very distantly related, some features of spinning silk seem to be universal. Both spiders and silkworms produce large silk proteins that are highly repetitive and extremely soluble at high pH, likely due to the globular terminal domains that flank an intermediate repetitive region. The silk proteins are produced and stored at a very high concentration in glands, and then transported along a narrowing tube in which they change conformation in response primarily to a pH gradient generated by carbonic anhydrase and proton pumps, as well as to ions and shear forces. The silk proteins thereby convert from random coil and alpha helical soluble conformations to beta sheet fibers. We suggest that factors that need to be optimized for successful production of artificial silk proteins capable of forming tough fibers include protein solubility, pH sensitivity, and preservation of natively folded proteins throughout the purification and initial spinning processes.

  13. The aerodynamic signature of running spiders.

    Directory of Open Access Journals (Sweden)

    Jérôme Casas

    Full Text Available Many predators display two foraging modes, an ambush strategy and a cruising mode. These foraging strategies have been classically studied in energetic, biomechanical and ecological terms, without considering the role of signals produced by predators and perceived by prey. Wolf spiders are a typical example; they hunt in leaf litter either using an ambush strategy or by moving at high speed, taking over unwary prey. Air flow upstream of running spiders is a source of information for escaping prey, such as crickets and cockroaches. However, air displacement by running arthropods has not been previously examined. Here we show, using digital particle image velocimetry, that running spiders are highly conspicuous aerodynamically, due to substantial air displacement detectable up to several centimetres in front of them. This study explains the bimodal distribution of spider's foraging modes in terms of sensory ecology and is consistent with the escape distances and speeds of cricket prey. These findings may be relevant to the large and diverse array of arthropod prey-predator interactions in leaf litter.

  14. SPiDer: Smart Pill Dispenser

    OpenAIRE

    Moreno Vázquez, Jonatan

    2013-01-01

    Aquest projecte proposa el sistema SPiDer el qual te l'objectiu d'assistir a la gent gran en el procés de medicar-se evitant els problemes associats amb la baixa adherència existent actualment amb els calendaris farmacològics receptats pels doctors.

  15. Status of the CNESM diagnostic for SPIDER

    International Nuclear Information System (INIS)

    Muraro, A.; Croci, G.; Albani, G.; Cazzaniga, C.; Claps, G.; Cavenago, M.; Grosso, G.; Palma, M. Dalla; Fincato, M.; Murtas, F.; Pasqualotto, R.; Cippo, E. Perelli; Rebai, M.; Tollin, M.; Tardocchi, M.; Gorini, G.

    2015-01-01

    Highlights: • We have finished the design of the detector box of the CNESM diagnostic for SPIDER. • We have constructed the GEM detector of the CNESM detector for SPIDER. • We have tested the detector under fast neutron irradiation. - Abstract: The ITER neutral beam test facility under construction in Padova will host two experimental devices: SPIDER, a 100 kV negative H/D RF source, and MITICA, a full scale, 1 MeV deuterium beam injector. A detection system called close-contact neutron emission surface mapping (CNESM) is under development with the aim to resolve the horizontal beam intensity profile in MITICA and one of the eight beamlet groups in SPIDER, with a spatial resolution of 1.5 and 2.5 cm respectively. This is achieved by the evaluation of the map of the neutron emission due to interaction of the deuterium beam with the deuterons implanted in the beam dump surface. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron–proton converter foil. The diagnostic will be placed right behind the SPIDER and MITICA beam dump, i.e. in an UHV environment, but the nGEM detectors need to operate at atmospheric pressure: in order to maintain the detector at atmospheric pressure, a vacuum sealed box, that will be mounted inside the vacuum, has been designed. The box design was driven by the need to minimize the neutron attenuation and the distance between the beam dump surface and the detector active area. This paper presents the status of the CNESM diagnostic describing the design of the detector, the design of the sealed box and reporting the results obtained with the first full-size prototype under fast neutron irradiation.

  16. Disease prevalence and transmission of Microsporidium phytoseiuli infecting the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Bjørnson, S; Keddie, B A

    2001-02-01

    Isolated colonies of the predatory mite, Phytoseiulus persimilis, were used to gain information regarding prevalence and transmission of Microsporidium phytoseiuli. Two colonies of P. persimilis were reared on spider mite (Tetranychus urticae)-infested bean plants in isolated cages. Disease prevalence of predators from Colony 1 remained relatively low (between 0 and 15%) over 57 weeks of observation whereas disease prevalence of predators from Colony 2 increased over 3 months (from 12 to 100%). Disease prevalence among predators from Colony 1 had increased to 100% 2 months after weekly sampling had ceased for this colony and periodic sampling confirmed that disease prevalence among individuals of both colonies remained at 100%. Microsporidian spores were not detected in randomly chosen samples of T. urticae prey mites that were removed and examined biweekly during this period. Although numerous microsporidian spores were observed in smear preparations of fecal pellets examined by light microscopy, spores were not observed on leaf surfaces or predator feces when examined by SEM. The latter appeared as intact aggregates composed of numerous dumbbell-shaped crystals and it is unlikely that spores are liberated from intact fecal pellets onto leaf surfaces. Vertical transmission of M. phytoseiuli was 100%; horizontal transmission was low (14.3%) and occurred only when immature P. persimilis were permitted to develop in contact with infected immature and adult predators. The mean number of eggs produced per mated pair was highest when uninfected females were mated with uninfected males (63.2 eggs per mated pair). Although mean egg production decreased when one or both parents were infected, not all differences were significant. Male predatory mites did not contribute to infection of their progeny. Results suggest that routine examination of P. persimilis for microsporidian spores is essential for the management of M. phytoseiuli within P. persimilis colonies. Low disease

  17. A Usages of Herb Extracts by Stream Integrated with Micro-organism to Control Insect Pests and Phytophagus Mites by Biological Control

    Energy Technology Data Exchange (ETDEWEB)

    Uraisakul, Kanok [Rajamangala University of Technology Suvarnabhumi Phranakhonsiayathaya, Hantra Campus, Phranakhonsiayathaya (Thailand); Piadang, Nattaya [Office of Atoms for Peace, Bangkok (Thailand)

    2006-09-15

    A usages of herb extracts by stream integrated rith micro-organism to control insect pests and phytophagus mites by biological control was compared with insecticide to investigate the responses of chili tree and kieffer lime tree. Moreover, herb extracts were tested in controlling insect pests. Herb extracts were selected from many effective kinds such as: Azadirachta indica, Hyptis suaveolens, Citronella grass, Eucalyptus, Stemona, Galangal, Zingiber, cassumunar Roxb. Chronmolaena oderatum, Derris elyptica, Ginger, Annona seed, Malueraca sp., Andrographis paniculata, Veronia aquarrosa, Garlic, Thevetia peruviana, and Tobacco. The experiment was set at Herb Laboratory Ayutthaya Campus, Rajamangala University of Technology, Suvarnabhumi during August 2004 to June 2006. From testing herb extracts at 100 ppm. On Chili germination, the result was that the Chromolaena extracts made highest germination of 69.50%, Citronella grass at 500 ppm., made highest germination of chili seed at 86.00% within 12 days. Garlic extracts could kill 75.90% of aphids in 24 hrs., maximized in this experiments. Malueraca extracts at 500 ppm. Could kill 92.65% of chili aphids similar to the activity of insecticides action in 24 hrs. However at 5,000 ppm. It found that chemical treatment gave difference results from herbal treatments. Annona extracts could kill 64.58% of chili aphids better that others treatments. There are 18 treatment of time at 6 hrs. , 15 hrs., and 24 hrs., respectively. The results found that at 6 hrs., Kelthane could kill 93.75% of red spider mite. At 15 hrs. Stemona could kill 95.50% of red spider mite. At 24 hrs. Stemona or Chromolaena could kill 100% of red spider mite equally, Chrolaena could kill more than 83% of chili thrips at 24 hrs. Annona extracts could harvest the maximum of fruit fresh weight and numbers of fruits. After cutting leaves for producing new leaves, spraying herbal extracts was not different in statistic; however, Eucalyptus extracts, Neem plus

  18. A Usages of Herb Extracts by Stream Integrated with Micro-organism to Control Insect Pests and Phytophagus Mites by Biological Control

    International Nuclear Information System (INIS)

    Uraisakul, Kanok; Piadang, Nattaya

    2006-09-01

    A usages of herb extracts by stream integrated rith micro-organism to control insect pests and phytophagus mites by biological control was compared with insecticide to investigate the responses of chili tree and kieffer lime tree. Moreover, herb extracts were tested in controlling insect pests. Herb extracts were selected from many effective kinds such as: Azadirachta indica, Hyptis suaveolens, Citronella grass, Eucalyptus, Stemona, Galangal, Zingiber, cassumunar Roxb. Chronmolaena oderatum, Derris elyptica, Ginger, Annona seed, Malueraca sp., Andrographis paniculata, Veronia aquarrosa, Garlic, Thevetia peruviana, and Tobacco. The experiment was set at Herb Laboratory Ayutthaya Campus, Rajamangala University of Technology, Suvarnabhumi during August 2004 to June 2006. From testing herb extracts at 100 ppm. On Chili germination, the result was that the Chromolaena extracts made highest germination of 69.50%, Citronella grass at 500 ppm., made highest germination of chili seed at 86.00% within 12 days. Garlic extracts could kill 75.90% of aphids in 24 hrs., maximized in this experiments. Malueraca extracts at 500 ppm. Could kill 92.65% of chili aphids similar to the activity of insecticides action in 24 hrs. However at 5,000 ppm. It found that chemical treatment gave difference results from herbal treatments. Annona extracts could kill 64.58% of chili aphids better that others treatments. There are 18 treatment of time at 6 hrs. , 15 hrs., and 24 hrs., respectively. The results found that at 6 hrs., Kelthane could kill 93.75% of red spider mite. At 15 hrs. Stemona could kill 95.50% of red spider mite. At 24 hrs. Stemona or Chromolaena could kill 100% of red spider mite equally, Chrolaena could kill more than 83% of chili thrips at 24 hrs. Annona extracts could harvest the maximum of fruit fresh weight and numbers of fruits. After cutting leaves for producing new leaves, spraying herbal extracts was not different in statistic; however, Eucalyptus extracts, Neem plus

  19. Anti-mite measurements in mite-sensitive adult asthma. A controlled trial.

    Science.gov (United States)

    Burr, M L; St Leger, A S; Neale, E

    1976-02-14

    A cross-over controlled trial has been conducted among 32 adult patients with mite-sensitive asthma. The bedclothes and pillows of each subject were laundered and vacuum-cleaned and a plastic cover applied to the mattress for six weeks in an attempt to reduce exposure to mites. No improvement in daily peak-flow reading or drug usage was found in comparison with a control period.

  20. A novel neurotoxin from venom of the spider, Brachypelma albopilosum.

    Directory of Open Access Journals (Sweden)

    Yunhua Zhong

    Full Text Available Spiders have evolved highly selective toxins for insects. There are many insecticidal neurotoxins in spider venoms. Although a large amount of work has been done to focus on neurotoxicity of spider components, little information, which is related with effects of spider toxins on tumor cell proliferation and cytotoxicity, is available for Brachypelma albopilosum venom. In this work, a novel spider neurotoxin (brachyin was identified and characterized from venoms of the spider, Brachypelma albopilosum. Brachyin is composed of 41 amino acid residues with the sequence of CLGENVPCDKDRPNCCSRYECLEPTGYGWWYASYYCYKKRS. There are six cysteines in this sequence, which form three disulfided bridges. The serine residue at the C-terminus is amidated. Brachyin showed strong lethal effects on American cockroaches (Periplaneta americana and Tenebrio molitor (common mealbeetle. This neurotoxin also showed significant analgesic effects in mice models including abdominal writhing induced by acetic acid and formalin-induced paw licking tests. It was interesting that brachyin exerted marked inhibition on tumor cell proliferation.

  1. Attention and amygdala activity: an fMRI study with spider pictures in spider phobia.

    Science.gov (United States)

    Alpers, Georg W; Gerdes, Antje B M; Lagarie, Bernadette; Tabbert, Katharina; Vaitl, Dieter; Stark, Rudolf

    2009-06-01

    Facilitated detection of threatening visual cues is thought to be adaptive. In theory, detection of threat cues should activate the amygdala independently from allocation of attention. However, previous studies using emotional facial expressions as well as phobic cues yielded contradictory results. We used fMRI to examine whether the allocation of attention to components of superimposed spider and bird displays modulates amygdala activation. Nineteen spider-phobic women were instructed to identify either a moving or a stationary animal in briefly presented double-exposure displays. Amygdala activation followed a dose-response relationship: Compared to congruent neutral displays (two birds), amygdala activation was most pronounced in response to congruent phobic displays (two spiders) and less but still significant in response to mixed displays (spider and bird) when attention was focused on the phobic component. When attention was focused on the neutral component, mixed displays did not result in significant amygdala activation. This was confirmed in a significant parametric graduation of the amygdala activation in the order of congruent phobic displays, mixed displays with attention focus on the spider, mixed displays with focus on the bird and congruent neutral displays. These results challenge the notion that amygdala activation in response to briefly presented phobic cues is independent from attention.

  2. What you fear will appear: detection of schematic spiders in spider fear.

    Science.gov (United States)

    Peira, Nathalie; Golkar, Armita; Larsson, Maria; Wiens, Stefan

    2010-01-01

    Various experimental tasks suggest that fear guides attention. However, because these tasks often lack ecological validity, it is unclear to what extent results from these tasks can be generalized to real-life situations. In change detection tasks, a brief interruption of the visual input (i.e., a blank interval or a scene cut) often results in undetected changes in the scene. This setup resembles real-life viewing behavior and is used here to increase ecological validity of the attentional task without compromising control over the stimuli presented. Spider-fearful and nonfearful women detected schematic spiders and flowers that were added to one of two identical background pictures that alternated with a brief blank in between them (i.e., flicker paradigm). Results showed that spider-fearful women detected spiders (but not flowers) faster than did nonfearful women. Because spiders and flowers had similar low-level features, these findings suggest that fear guides attention on the basis of object features rather than simple low-level features.

  3. Learning to avoid spiders: fear predicts performance, not competence.

    Science.gov (United States)

    Luo, Xijia; Becker, Eni S; Rinck, Mike

    2018-01-05

    We used an immersive virtual environment to examine avoidance learning in spider-fearful participants. In 3 experiments, participants were asked to repeatedly lift one of 3 virtual boxes, under which either a toy car or a spider appeared and then approached the participant. Participants were not told that the probability of encountering a spider differed across boxes. When the difference was large (Exps. 1 and 2), spider-fearfuls learned to avoid spiders by lifting the few-spiders-box more often and the many-spiders-box less often than non-fearful controls did. However, they hardly managed to do so when the probability differences were small (Exp. 3), and they did not escape from threat more quickly (Exp. 2). In contrast to the observed performance differences, spider-fearfuls and non-fearfuls showed equal competence, that is comparable post-experimental knowledge about the probability to encounter spiders under the 3 boxes. The limitations and implications of the present study are discussed.

  4. Sex-specific kleptoparasitic foraging in ant-eating spiders

    DEFF Research Database (Denmark)

    Martisová, Martina; Bilde, T.; Pekar, Stano

    2009-01-01

    . To investigate this hypothesis, we studied the effect of sex and life history stage on the frequency of kleptoparasitism in ant-eating spiders of the genus Zodarion in the field. These spiders use a special capture technique involving a quick attack on an ant that is left unguarded by spiders for several minutes......, providing ample opportunities for kleptoparasitism. We found that adult females consistently hunted actively, while adult males ceased active prey capture and instead engaged in kleptoparasitism. Juvenile spiders were active hunters irrespective of sex. Consistent with an ontogenetic shift in foraging...

  5. Second-order nonlinear optical microscopy of spider silk

    Science.gov (United States)

    Zhao, Yue; Hien, Khuat Thi Thu; Mizutani, Goro; Rutt, Harvey N.

    2017-06-01

    Asymmetric β-sheet protein structures in spider silk should induce nonlinear optical interaction such as second harmonic generation (SHG) which is experimentally observed for a radial line and dragline spider silk using an imaging femtosecond laser SHG microscope. By comparing different spider silks, we found that the SHG signal correlates with the existence of the protein β-sheets. Measurements of the polarization dependence of SHG from the dragline indicated that the β-sheet has a nonlinear response depending on the direction of the incident electric field. We propose a model of what orientation the β-sheet takes in spider silk.

  6. Recent advances in the understanding of brown spider venoms: From the biology of spiders to the molecular mechanisms of toxins.

    Science.gov (United States)

    Gremski, Luiza Helena; Trevisan-Silva, Dilza; Ferrer, Valéria Pereira; Matsubara, Fernando Hitomi; Meissner, Gabriel Otto; Wille, Ana Carolina Martins; Vuitika, Larissa; Dias-Lopes, Camila; Ullah, Anwar; de Moraes, Fábio Rogério; Chávez-Olórtegui, Carlos; Barbaro, Katia Cristina; Murakami, Mario Tyago; Arni, Raghuvir Krishnaswamy; Senff-Ribeiro, Andrea; Chaim, Olga Meiri; Veiga, Silvio Sanches

    2014-06-01

    The Loxosceles genus spiders (the brown spiders) are encountered in all the continents, and the clinical manifestations following spider bites include skin necrosis with gravitational lesion spreading and occasional systemic manifestations, such as intravascular hemolysis, thrombocytopenia and acute renal failure. Brown spider venoms are complex mixtures of toxins especially enriched in three molecular families: the phospholipases D, astacin-like metalloproteases and Inhibitor Cystine Knot (ICK) peptides. Other toxins with low level of expression also present in the venom include the serine proteases, serine protease inhibitors, hyaluronidases, allergen factors and translationally controlled tumor protein (TCTP). The mechanisms by which the Loxosceles venoms act and exert their noxious effects are not fully understood. Except for the brown spider venom phospholipase D, which causes dermonecrosis, hemolysis, thrombocytopenia and renal failure, the pathological activities of the other venom toxins remain unclear. The objective of the present review is to provide insights into the brown spider venoms and loxoscelism based on recent results. These insights include the biology of brown spiders, the clinical features of loxoscelism and the diagnosis and therapy of brown spider bites. Regarding the brown spider venom, this review includes a description of the novel toxins revealed by molecular biology and proteomics techniques, the data regarding three-dimensional toxin structures, and the mechanism of action of these molecules. Finally, the biotechnological applications of the venom components, especially for those toxins reported as recombinant molecules, and the challenges for future study are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Araneae Sloveniae: a national spider species checklist.

    Science.gov (United States)

    Kostanjšek, Rok; Kuntner, Matjaž

    2015-01-01

    The research of the spider fauna of Slovenia dates back to the very beginning of binomial nomenclature, and has gone through more and less prolific phases with authors concentrating on taxonomy, faunistics, ecology and zoogeographic reviews. Although the body of published works is remarkable for a small nation, the faunistic data has remained too scattered for a thorough understanding of regional biotic diversity, for comparative and ecological research, and for informed conservation purposes. A national checklist is long overdue. Here, a critical review of all published records in any language is provided. The species list currently comprises 738 species, is published online at http://www.bioportal.si/katalog/araneae.php under the title Araneae Sloveniae, and will be updated in due course. This tool will fill the void in cataloguing regional spider faunas and will facilitate further araneological research in central and southern Europe.

  8. Logic circuits based on molecular spider systems.

    Science.gov (United States)

    Mo, Dandan; Lakin, Matthew R; Stefanovic, Darko

    2016-08-01

    Spatial locality brings the advantages of computation speed-up and sequence reuse to molecular computing. In particular, molecular walkers that undergo localized reactions are of interest for implementing logic computations at the nanoscale. We use molecular spider walkers to implement logic circuits. We develop an extended multi-spider model with a dynamic environment wherein signal transmission is triggered via localized reactions, and use this model to implement three basic gates (AND, OR, NOT) and a cascading mechanism. We develop an algorithm to automatically generate the layout of the circuit. We use a kinetic Monte Carlo algorithm to simulate circuit computations, and we analyze circuit complexity: our design scales linearly with formula size and has a logarithmic time complexity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Araneae Sloveniae: a national spider species checklist

    Directory of Open Access Journals (Sweden)

    Rok Kostanjšek

    2015-01-01

    Full Text Available The research of the spider fauna of Slovenia dates back to the very beginning of binomial nomenclature, and has gone through more and less prolific phases with authors concentrating on taxonomy, faunistics, ecology and zoogeographic reviews. Although the body of published works is remarkable for a small nation, the faunistic data has remained too scattered for a thorough understanding of regional biotic diversity, for comparative and ecological research, and for informed conservation purposes. A national checklist is long overdue. Here, a critical review of all published records in any language is provided. The species list currently comprises 738 species, is published online at http://www.bioportal.si/katalog/araneae.php under the title Araneae Sloveniae, and will be updated in due course. This tool will fill the void in cataloguing regional spider faunas and will facilitate further araneological research in central and southern Europe.

  10. Pyroglyphid mites as a source of work-related allergens.

    Science.gov (United States)

    Macan, Jelena; Kanceljak-Macan, Božica; Milković-Kraus, Sanja

    2012-01-01

    Pyroglyphid mites are primarily associated with allergen exposure at home; hence the name house dust mites. However, we have found numerous studies reporting pyroglyhid mite levels in public and occupational settings. This review presents the findings of house dust mite allergens (family Pyroglyphidae, species Dermatophagoides) as potential work-related risk factors and proposes occupations at risk of house dust mite-related diseases. Pyroglyphid mites or their allergens are found in various workplaces, but clinically relevant exposures have been observed in hotels, cinemas, schools, day-care centres, libraries, public transportation (buses, trains, taxies, and airplanes), fishing-boats, submarines, poultry farms, and churches. Here we propose a classification of occupational risk as low (occasional exposure to mite allergen levels up to 2 μg g(-1)), moderate (exposure between 2 μg g(-1) and 10 μg g(-1)), and high (exposure >10 μg g(-1)). The classification of risk should include factors relevant for indoor mite population (climate, building characteristics, and cleaning schedule). To avoid development or aggravation of allergies associated with exposure to house dust mites at work, occupational physicians should assess exposure risk at work, propose proper protection, provide vocational guidance to persons at risk and conduct pre-employment and periodic examinations to diagnose new allergy cases. Protection at work should aim to control dust mite levels at work. Measures may include proper interior design and regular cleaning and building maintenance.

  11. Nanofibre production in spiders without electric charge.

    Science.gov (United States)

    Joel, Anna-Christin; Baumgartner, Werner

    2017-06-15

    Technical nanofibre production is linked to high voltage, because nanofibres are typically produced by electrospinning. In contrast, spiders have evolved a way to produce nanofibres without high voltage. These spiders are called cribellate spiders and produce nanofibres within their capture thread production. It is suggested that their nanofibres become frictionally charged when brushed over a continuous area on the calamistrum, a comb-like structure at the metatarsus of the fourth leg. Although there are indications that electrostatic charges are involved in the formation of the thread structure, final proof is missing. We proposed three requirements to validate this hypothesis: (1) the removal of any charge during or after thread production has an influence on the structure of the thread; (2) the characteristic structure of the thread can be regenerated by charging; and (3) the thread is attracted to or repelled from differently charged objects. None of these three requirements were proven true. Furthermore, mathematical calculations reveal that even at low charges, the calculated structural assembly of the thread does not match the observed reality. Electrostatic forces are therefore not involved in the production of cribellate capture threads. © 2017. Published by The Company of Biologists Ltd.

  12. Progress on development of SPIDER diagnostics

    Science.gov (United States)

    Pasqualotto, R.; Agostini, M.; Barbisan, M.; Bernardi, M.; Brombin, M.; Cavazzana, R.; Croci, G.; Palma, M. Dalla; Delogu, R. S.; Gorini, G.; Lotto, L.; Muraro, A.; Peruzzo, S.; Pimazzoni, A.; Pomaro, N.; Rizzolo, A.; Serianni, G.; Spolaore, M.; Tardocchi, M.; Zaniol, B.; Zaupa, M.

    2017-08-01

    SPIDER experiment, the full size prototype of the beam source for the ITER heating neutral beam injector, has to demonstrate extraction and acceleration to 100 kV of a large negative ion hydrogen or deuterium beam with co-extracted electron fraction e-/D- SPIDER plant systems are being installed, the different diagnostic systems are in the procurement phase. Their final design is described here with a focus on some key solutions and most original and cost effective implementations. Thermocouples used to measure the power load distribution in the source and over the beam dump front surface will be efficiently fixed with proven technique and acquired through commercial and custom electronics. Spectroscopy needs to use well collimated lines of sight and will employ novel design spectrometers with higher efficiency and resolution and filtered detectors with custom built amplifiers. The electrostatic probes will be operated through electronics specifically developed to cope with the challenging environment of the RF source. The instrumented calorimeter STRIKE will use new CFC tiles, still under development. Two linear cameras, one built in house, have been tested as suitable for optical beam tomography. Some diagnostic components are off the shelf, others are custom developed: some of these are being prototyped or are under test before final production and installation, which will be completed before start of SPIDER operation.

  13. Tri-trophic level impact of host plant linamarin and lotaustralin on Tetranychus urticae and its predator Phytoseiulus persimilis.

    Science.gov (United States)

    Rojas, M Guadalupe; Morales-Ramos, Juan Alfredo

    2010-12-01

    The impact of linamarin and lotaustralin content in the leaves of lima beans, Phaseolus lunatus L., on the second and third trophic levels was studied in the two-spotted spider mite, Tetranychus urticae (Koch), and its predator Phytoseiulus persimilis Athias-Henriot. The content of linamarin was higher in terminal trifoliate leaves (435.5 ppm) than in primary leaves (142.1 ppm) of Henderson bush lima beans. However, linamarin concentrations were reversed at the second trophic level showing higher concentrations in spider mites feeding on primary leaves (429.8 ppm) than those feeding on terminal trifoliate leaves (298.2 ppm). Concentrations of linamarin in the predatory mites were 18.4 and 71.9 ppm when feeding on spider mites grown on primary and terminal leaves, respectively. The concentration of lotaustralin in primary lima bean leaves was 103.12 ppm, and in spider mites feeding on these leaves was 175.0 ppm. Lotaustralin was absent in lima bean terminal trifoliate leaves and in mites feeding on these leaves. Fecundity of spider mites feeding on lima bean leaves (primary or trifoliate) was not significantly different from mites feeding on red bean, Phaseolus vulgaris L., primary leaves. However, the progeny sex ratio (in females per male) of spider mites feeding on lima bean leaves was significantly lower than progeny of spider mites feeding on red bean leaves (control). Fecundity and progeny sex ratio of P. persimilis were both significantly affected by the concentration of linamarin present in the prey. Changes in concentration of linamarin in living tissue across the three trophic levels are discussed.

  14. Interactions in a tritrophic acarine predator-prey metapopulation system V: within-plant dynamics of Phytoseiulus persimilis and Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae).

    Science.gov (United States)

    Nachman, Gösta; Zemek, Rostislav

    2003-01-01

    To investigate the relative contributions of bottom-up (plant condition) and top-down (predatory mites) factors on the dynamics of the two-spotted spider mite (Tetranychus urticae), a series of experiments were conducted in which spider mites and predatory mites were released on bean plants. Plants inoculated with 2, 4, 8, 16, and 32 adult female T. urticae were either left untreated or were inoculated with 3 or 5 adult female predators (Phytoseiulus persimilis) one week after the introduction of spider mites. Plant area, densities of T. urticae and P. persimilis, and plant injury were assessed by weekly sampling. Data were analysed by a combination of statistical methods and a tri-trophic mechanistic simulation model partly parameterised from the current experiments and partly from previous data. The results showed a clear effect of predators on the density of spider mites and on the plant injury they cause. Plant injury increased with the initial number of spider mites and decreased with the initial number of predators. Extinction of T. urticae, followed by extinction of P. persimilis, was the most likely outcome for most initial combinations of prey and predators. Eggs constituted a relatively smaller part of the prey population as plant injury increased and of the predator population as prey density decreased. We did not find statistical evidence of P. persimilis having preference for feeding on T. urticae eggs. The simulation model demonstrated that bottom-up and top-down factors interact synergistically to reduce the density of spider mites. This may have important implications for biological control of spider mites by means of predatory mites.

  15. Integration of multiple intraguild predator cues for oviposition decisions by a predatory mite

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2012-01-01

    In mutual intraguild predation (IGP), the role of individual guild members is strongly context dependent and, during ontogeny, can shift from an intraguild (IG) prey to a food competitor or to an IG predator. Consequently, recognition of an offspring's predator is more complex for IG than classic prey females. Thus, IG prey females should be able to modulate their oviposition decisions by integrating multiple IG predator cues and by experience. Using a guild of plant-inhabiting predatory mites sharing the spider mite Tetranychus urticae as prey and passing through ontogenetic role shifts in mutual IGP, we assessed the effects of single and combined direct cues of the IG predator Amblyseius andersoni (eggs and traces left by a female on the substrate) on prey patch selection and oviposition behaviour of naïve and IG predator-experienced IG prey females of Phytoseiulus persimilis. The IG prey females preferentially resided in patches without predator cues when the alternative patch contained traces of predator females or the cue combination. Preferential egg placement in patches without predator cues was only apparent in the choice situation with the cue combination. Experience increased the responsiveness of females exposed to the IG predator cue combination, indicated by immediate selection of the prey patch without predator cues and almost perfect oviposition avoidance in patches with the cue combination. We argue that the evolution of the ability of IG prey females to evaluate offspring's IGP risk accurately is driven by the irreversibility of oviposition and the functionally complex relationships between predator guild members. PMID:23264692

  16. Balancing in- and out-breeding by the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Atalay, Demet; Schausberger, Peter

    2018-02-01

    In- and out-breeding depressions are commonly observed phenomena in sexually reproducing organisms with a patchy distribution pattern, and spatial segmentation and/or isolation of groups. At the genetic level, inbreeding depression is due to increased homozygosity, whereas outbreeding depression is due to inferior genetic compatibility of mates. Optimal outbreeding theory suggests that intermediate levels of mate relatedness should provide for the highest fitness gains. Here, we assessed the fitness consequences of genetic relatedness between mates in plant-inhabiting predatory mites Phytoseiulus persimilis, which are obligatory sexually reproducing but haplo-diploid. Both females and males arise from fertilized eggs but males lose the paternal chromosome set during embryogenesis, dubbed pseudo-arrhenotoky. Phytoseiulus persimilis are highly efficacious in reducing crop-damaging spider mite populations and widely used in biological control. Using iso-female lines of two populations, from Sicily and Greece, we assessed the fecundity of females, and sex ratio of their offspring, that mated with either a sibling, a male from the same population or a male from the other population. Additionally, we recorded mating latency and duration. Females mating with a male from the same population produced more eggs, with a lower female bias, over a longer time than females mating with a sibling or with a male from the other population. Mating latency was unaffected by mate relatedness; mating duration was disproportionally long in sibling couples, likely indicating female reluctance to mate and sub-optimal spermatophore transfer. Our study provides a rare example of in- and out-breeding depression in a haplo-diploid arthropod, supporting the optimal outbreeding theory.

  17. Clathrin Heavy Chain Is Important for Viability, Oviposition, Embryogenesis and, Possibly, Systemic RNAi Response in the Predatory Mite Metaseiulus occidentalis

    Science.gov (United States)

    Wu, Ke; Hoy, Marjorie A.

    2014-01-01

    Clathrin heavy chain has been shown to be important for viability, embryogenesis, and RNA interference (RNAi) in arthropods such as Drosophila melanogaster. However, the functional roles of clathrin heavy chain in chelicerate arthropods, such as the predatory mite Metaseiulus occidentalis, remain unknown. We previously showed that dsRNA ingestion, followed by feeding on spider mites, induced systemic and robust RNAi in M. occidentalis females. In the current study, we performed a loss-of-function analysis of the clathrin heavy chain gene in M. occidentalis using RNAi. We showed that ingestion of clathrin heavy chain dsRNA by M. occidentalis females resulted in gene knockdown and reduced longevity. In addition, clathrin heavy chain dsRNA treatment almost completely abolished oviposition by M. occidentalis females and the few eggs produced did not hatch. Finally, we demonstrated that clathrin heavy chain gene knockdown in M. occidentalis females significantly reduced a subsequent RNAi response induced by ingestion of cathepsin L dsRNA. The last finding suggests that clathrin heavy chain may be involved in systemic RNAi responses mediated by orally delivered dsRNAs in M. occidentalis. PMID:25329675

  18. The role of web sharing, species recognition and host-plant defence in interspecific competition between two herbivorous mite species.

    Science.gov (United States)

    Sato, Yukie; Alba, Juan M; Egas, Martijn; Sabelis, Maurice W

    2016-11-01

    When competing with indigenous species, invasive species face a problem, because they typically start with a few colonizers. Evidently, some species succeeded, begging an answer to the question how they invade. Here, we investigate how the invasive spider mite Tetranychus evansi interacts with the indigenous species T. urticae when sharing the solanaceous host plant tomato: do they choose to live together or to avoid each other's colonies? Both species spin protective, silken webs on the leaf surfaces, under which they live in groups of con- and possibly heterospecifics. In Spain, T. evansi invaded the non-crop field where native Tetranychus species including T. urticae dominated. Moreover, T. evansi outcompetes T. urticae when released together on a tomato plant. However, molecular plant studies suggest that T. urticae benefits from the local down-regulation of tomato plant defences by T. evansi, whereas T. evansi suffers from the induction of these defences by T. urticae. Therefore, we hypothesize that T. evansi avoids leaves infested with T. urticae whereas T. urticae prefers leaves infested by T. evansi. Using wild-type tomato and a mutant lacking jasmonate-mediated anti-herbivore defences, we tested the hypothesis and found that T. evansi avoided sharing webs with T. urticae in favour of a web with conspecifics, whereas T. urticae more frequently chose to share webs with T. evansi than with conspecifics. Also, T. evansi shows higher aggregation on a tomato plant than T. urticae, irrespective of whether the mites occur on the plant together or not.

  19. Structure–Activity Relationship Study of Spider Polyamine Toxins as Inhibitors of Ionotropic Glutamate Receptors

    DEFF Research Database (Denmark)

    Xiong, Xiaofeng; Poulsen, Mette H; Hussein, Rama A

    2014-01-01

    The spider polyamine toxins Joro spider toxin-3 (JSTX-3) and Nephila polyamine toxins-1 and -8 (NPTX-1 and NPTX-8) are isolated from the venom of the orb-weaver spider Nephila clavata (Joro spider). They share a high degree of structural resemblance, their aromatic head groups being the only...

  20. Who is afraid of a black Spider(-Man)?

    OpenAIRE

    Ora C. McWilliams

    2013-01-01

    An Internet post asking about Spider-Man's race in a film turned into an Internet campaign about an actor that led fans to interact with each other as well as with the actor, which in turn led to the attention of media producers, which resulted in a change in Spider-Man's race in a print comic book.

  1. Who is afraid of a black Spider(-Man?

    Directory of Open Access Journals (Sweden)

    Ora C. McWilliams

    2013-06-01

    Full Text Available An Internet post asking about Spider-Man's race in a film turned into an Internet campaign about an actor that led fans to interact with each other as well as with the actor, which in turn led to the attention of media producers, which resulted in a change in Spider-Man's race in a print comic book.

  2. Spider diversity in relation to habitat heterogeneity and an altitudinal ...

    African Journals Online (AJOL)

    Using pitfall traps, wandering spiders (Arachnida: Araneae) were sampled in a nested design from three different localities in the mountainous arid ecosystem of South Sinai at low, middle, and high altitudes. Habitat type and altitude were clearly different among the three localities. Spider diversity per trap varied spatially ...

  3. Time-dependent motor properties of multipedal molecular spiders.

    Science.gov (United States)

    Samii, Laleh; Blab, Gerhard A; Bromley, Elizabeth H C; Linke, Heiner; Curmi, Paul M G; Zuckermann, Martin J; Forde, Nancy R

    2011-09-01

    Molecular spiders are synthetic biomolecular walkers that use the asymmetry resulting from cleavage of their tracks to bias the direction of their stepping motion. Using Monte Carlo simulations that implement the Gillespie algorithm, we investigate the dependence of the biased motion of molecular spiders, along with binding time and processivity, on tunable experimental parameters, such as number of legs, span between the legs, and unbinding rate of a leg from a substrate site. We find that an increase in the number of legs increases the spiders' processivity and binding time but not their mean velocity. However, we can increase the mean velocity of spiders with simultaneous tuning of the span and the unbinding rate of a spider leg from a substrate site. To study the efficiency of molecular spiders, we introduce a time-dependent expression for the thermodynamic efficiency of a molecular motor, allowing us to account for the behavior of spider populations as a function of time. Based on this definition, we find that spiders exhibit transient motor function over time scales of many hours and have a maximum efficiency on the order of 1%, weak compared to other types of molecular motors.

  4. Evidence for competition between carnivorous plants and spiders.

    Science.gov (United States)

    Jennings, David E; Krupa, James J; Raffel, Thomas R; Rohr, Jason R

    2010-10-07

    Several studies have demonstrated that competition between disparate taxa can be important in determining community structure, yet surprisingly, to our knowledge, no quantitative studies have been conducted on competition between carnivorous plants and animals. To examine potential competition between these taxa, we studied dietary and microhabitat overlap between pink sundews (Drosera capillaris) and wolf spiders (Lycosidae) in the field, and conducted a laboratory experiment examining the effects of wolf spiders on sundew fitness. In the field, we found that sundews and spiders had a high dietary overlap with each other and with the available arthropod prey. Associations between sundews and spiders depended on spatial scale: both sundews and spiders were found more frequently in quadrats with more abundant prey, but within quadrats, spiders constructed larger webs and located them further away from sundews as the total sundew trapping area increased, presumably to reduce competition. Spiders also constructed larger webs when fewer prey were available. In the laboratory, our experiment revealed that spiders can significantly reduce sundew fitness. Our findings suggest that members of the plant and animal kingdoms can and do compete.

  5. Are temperate canopy spiders tree-species specific?

    Science.gov (United States)

    Mupepele, Anne-Christine; Müller, Tobias; Dittrich, Marcus; Floren, Andreas

    2014-01-01

    Arboreal spiders in deciduous and coniferous trees were investigated on their distribution and diversity. Insecticidal knock-down was used to comprehensively sample spiders from 175 trees from 2001 to 2003 in the Białowieża forest and three remote forests in Poland. We identified 140 species from 9273 adult spiders. Spider communities were distinguished between deciduous and coniferous trees. The richest fauna was collected from Quercus where beta diversity was also highest. A tree-species-specific pattern was clearly observed for Alnus, Carpinus, Picea and Pinus trees and also for those tree species that were fogged in only four or three replicates, namely Betula and Populus. This hitherto unrecognised association was mainly due to the community composition of common species identified in a Dufrene-Legendre indicator species analysis. It was not caused by spatial or temporal autocorrelation. Explaining tree-species specificity for generalist predators like spiders is difficult and has to involve physical and ecological tree parameters like linkage with the abundance of prey species. However, neither did we find a consistent correlation of prey group abundances with spiders nor could differences in spider guild composition explain the observed pattern. Our results hint towards the importance of deterministic mechanisms structuring communities of generalist canopy spiders although the casual relationship is not yet understood.

  6. Camel spider (Solifugae) use of prairie dog colonies

    Science.gov (United States)

    Solifugids (camel spiders) are widespread throughout arid regions of western North America and are thought to be important in structuring desert arthropod communities. Despite the ubiquity of camel spiders, little is known about their ecology. Black-tailed prairie dogs (Cynomys ludovicianus) are als...

  7. Brain systems underlying encounter expectancy bias in spider phobia.

    Science.gov (United States)

    Aue, Tatjana; Hoeppli, Marie-Eve; Piguet, Camille; Hofstetter, Christoph; Rieger, Sebastian W; Vuilleumier, Patrik

    2015-06-01

    Spider-phobic individuals are characterized by exaggerated expectancies to be faced with spiders (so-called encounter expectancy bias). Whereas phobic responses have been linked to brain systems mediating fear, little is known about how the recruitment of these systems relates to exaggerated expectancies of threat. We used fMRI to examine spider-phobic and control participants while they imagined visiting different locations in a forest after having received background information about the likelihood of encountering different animals (spiders, snakes, and birds) at these locations. Critically, imagined encounter expectancies modulated brain responses differently in phobics as compared with controls. Phobics displayed stronger negative modulation of activity in the lateral prefrontal cortex, precuneus, and visual cortex by encounter expectancies for spiders, relative to snakes or birds (within-participants analysis); these effects were not seen in controls. Between-participants correlation analyses within the phobic group further corroborated the hypothesis that these phobia-specific modulations may underlie irrationality in encounter expectancies (deviations of encounter expectancies from objective background information) in spider phobia; the greater the negative modulation a phobic participant displayed in the lateral prefrontal cortex, precuneus, and visual cortex, the stronger was her bias in encounter expectancies for spiders. Interestingly, irrationality in expectancies reflected in frontal areas relied on right rather than left hemispheric deactivations. Our data accord with the idea that expectancy biases in spider phobia may reflect deficiencies in cognitive control and contextual integration that are mediated by right frontal and parietal areas.

  8. Three newly recorded Linyphiid spiders (Araneae: Linyphiidae from Korea

    Directory of Open Access Journals (Sweden)

    Sue Yeon Lee

    2018-03-01

    Full Text Available Three Linyphiid spiders, Caviphantes pseudosaxetorum Wunderlich, 1979, Erigone edentata Saito and Ono, 2001, and Savignia kawachiensis Oi, 1960, are reported for the first time from Korea with taxonomic illustrations and redescription. In this study, the genus Caviphantes Oi, 1960 is also newly recorded to Korean spider fauna.

  9. Under the lash: Demodex mites in human diseases

    OpenAIRE

    Lacey, Noreen; Kavanagh, Kevin; Tseng, Scheffer C.G.

    2009-01-01

    Demodex mites, class Arachnida and subclass Acarina, are elongated mites with clear cephalothorax and abdomens, the former with four pairs of legs. There are more than 100 species of Demodex mite, many of which are obligatory commensals of the pilosebaceous unit of mammals including cats, dogs, sheep, cattle, pigs, goats, deer, bats, hamsters, rats and mice. Among them, Demodex canis, which is found ubiquitously in dogs, is the most documented and investigated. In excessive numbers D. canis c...

  10. Long conduction time POs experiments on MITE

    International Nuclear Information System (INIS)

    Woodall, H.N.; McDaniel, D.H.; Mendel, C.W.; Rochau, G.E.; Zagar, D.M.; Simpson, W.W.; Zuchowski, N.P.

    1990-01-01

    MITE is a power flow test bed that has been modified to conduct experiments in high power plasma opening switch (POS) technology and apply this technology to Inertial Confinement Fusion. The goal of the experiment is to develop a plasma opening switch that conducts megampere currents for 300 ns, then opens in 5--10 ns. MITE/POS is an advanced power flow experiment that uses a magnetically insulated transmission line (MITL) as the inductive energy store and as a means to shape the output pulse. This experiment demonstrates that a simplified, lower-cost facility can be built by eliminating water pulse-forming lines and water-switching. Another advantage of this approach is that high energy efficiency at peak power can be achieved. The disadvantage is that a new technology, the triggered POS, must be implemented. The triggered POS is necessary for synchronization of multiple modules with a long conduction-time POS. The MITE facility has been modified to drive a 250 nH, 16.6 Ohm MITL at 0.9 MA to accommodate this power flow experiment. A MITL inductive energy storage of 101 kJ is available for POS switching to a matched load. Experiments have been conducted using segmented flashboards and magnetic-field controlled plasma sources. These experiments will lead to the development of the triggered POS. The initial experiments with plasma conduction times of 120 ns to 800 ns are discussed

  11. SPIDER: CMB Polarimetry from the Edge of Space

    Energy Technology Data Exchange (ETDEWEB)

    Gualtieri, R.; et al.

    2017-11-28

    SPIDER is a balloon-borne instrument designed to map the polarization of the millimeter-wave sky at large angular scales. SPIDER targets the B-mode signature of primordial gravitational waves in the cosmic microwave background (CMB), with a focus on mapping a large sky area with high fidelity at multiple frequencies. SPIDER's first longduration balloon (LDB) flight in January 2015 deployed a total of 2400 antenna-coupled Transition Edge Sensors (TESs) at 90 GHz and 150 GHz. In this work we review the design and in-flight performance of the SPIDER instrument, with a particular focus on the measured performance of the detectors and instrument in a space-like loading and radiation environment. SPIDER's second flight in December 2018 will incorporate payload upgrades and new receivers to map the sky at 285 GHz, providing valuable information for cleaning polarized dust emission from CMB maps.

  12. Nutrient regulation in a predator, the wolf spider Pardosa prativaga

    DEFF Research Database (Denmark)

    Jensen, Kim; Mayntz, David; Toft, Søren

    2011-01-01

    Nutrient balancing is well known in herbivores and omnivores, but has only recently been demonstrated in predators. To test how a predator might regulate nutrients when the prey varies in nutrient composition, we restricted juvenile Pardosa prativaga wolf spiders to diets of one of six fruit fly......, Drosophila melanogaster, prey types varying in lipid:protein composition during their second instar. We collected all fly remnants to estimate food and nutrient intake over each meal. The spiders adjusted their capture rate and nutrient extraction in response to prey mass and nutrient composition...... irrespective of energy intake. Intake was initially regulated to a constant lipid plus protein mass, but later spiders fed on prey with high proportions of protein increased consumption relative to spiders fed on other prey types. This pattern indicates that the spiders were prepared to overconsume vast...

  13. Spiders of Kerala Agricultural University Campus, Thrissur, Kerala, India

    Directory of Open Access Journals (Sweden)

    C. K. Adarsh

    2015-12-01

    Full Text Available A total of 86 species of spiders belonging to 56 genera of 20 families have been recorded from the Kerala Agricultural University (KAU campus, Thrissur, Kerala, southern India.  This represents 5.1% of the total spiders’ species and 33.33% of the total families of spiders recorded in India.  The dominant spider family at KAU campus is Araneidae with 18 species of nine genera. Salticidae is represented by 14 species of 13 genera.  Out of 252 endemic spiders of India, 16 have been reported from KAU campus.  Guild structure analysis shows spiders belonging to seven types of feeding guilds present in KAU campus.  Orb-web builders are the dominant feeding guild accounting for 34%, followed by stalkers (22%, ground runners (20%, ambushers (8%, scattered line weavers (8%, foliage runners (7% and sheet-web builders (1%. 

  14. Specific predictive power of automatic spider-related affective associations for controllable and uncontrollable fear responses toward spiders

    NARCIS (Netherlands)

    Huijdlng, J; de Jong, PJ; Huijding, J.

    This study examined the predictive power of automatically activated spider-related affective associations for automatic and controllable fear responses. The Extrinsic Affective Simon Task (EAST; De Houwer, 2003) was used to indirectly assess automatic spider fear-related associations. The EAST and

  15. And along Came a Spider: An Attentional Bias for the Detection of Spiders in Young Children and Adults

    Science.gov (United States)

    LoBue, Vanessa

    2010-01-01

    Spiders are among the most common targets of fears and phobias in the world. In visual search tasks, adults detect their presence more rapidly than other kinds of stimuli. Reported here is an investigation of whether young children share this attentional bias for the detection of spiders. In a series of experiments, preschoolers and adults were…

  16. Solubilization of spider silk proteins and its structural analysis using Fourier transform infrared spectroscopy

    Science.gov (United States)

    Osbin, K.; Jayan, Manuel; Bhadrakumari, S.; Predeep, P.

    2017-06-01

    This study investigates the presence of various amide bands present in different spider silk species, which provides extraordinary physical properties. Three different spider silks were collected from Western Ghats region. The collected spider silks samples belonging to the spider Heteropoda venatoria (species 1), Hersilia savignyi (species 2) and Pholcus phalangioides (species 3). Fourier transform infrared (FTIR) spectra reveals the protein peaks in the amide I, II, and III regions in all the three types of spider silk species.

  17. Clinical benefits of treatment with SQ house dust mite sublingual tablet in house dust mite allergic rhinitis.

    Science.gov (United States)

    Demoly, P; Kleine-Tebbe, J; Rehm, D

    2017-10-01

    Treatment with SQ (standardised quality) house dust mite sublingual tablet for 1 year resulted in a decreased probability of having an allergic rhinitis (AR) exacerbation day (from 11% [placebo] to 5% [SQ house dust mite sublingual tablet]) and an increased probability of having a mild AR day (from 16% [placebo] to 34% [SQ house dust mite sublingual tablet]). © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

  18. The Transmission Line for the SPIDER experiment

    International Nuclear Information System (INIS)

    Boldrin, Marco; De Lorenzi, Antonio; Recchia, Mauro; Toigo, Vanni; Bonicelli, Tullio; Simon, Muriel

    2011-01-01

    The 100 keV Ion Source Test facility - Source for the Production of Ions of Deuterium Extracted from RF plasma (SPIDER) - is aimed to test the full scale prototype of the Ion Source for the ITER 1 MeV Neutral Beam Injector (NBI). The SPIDER facility requires the construction of a High Voltage Deck (HVD) and of a High Voltage Transmission Line (TL) respectively to host the Ion Source Power Supplies system polarized at 100 kV and to carry the power and signal conductors to the beam accelerator. In already existing NBI systems with beam energy above 100 keV, the TL is realized with the SF 6 Gas Insulated Line technology. In the SPIDER TL case, the presence of a large inner conductor (half meter diameter), would make the pressurized TL a complex and costly component; therefore a free air insulated solution has been proposed. The paper focuses on the design of this TL, which has to host inside the complex high potential (100 kV) inner electrode a number of power and measuring conductors and has to minimize the Electro Magnetic Interferences (EMI) produced by the frequent grids breakdowns. Finite Element (FE) analyses have been performed to verify the configuration from the electrostatic point of view, to evaluate EMI screening effectiveness and to assess the impact of the relatively high thermal dissipation of power conductors located inside the high potential electrode. Moreover, an experimental test campaign has been carried out on a TL mockup to validate the TL electrostatic configuration under DC voltage. Finally, the paper reports on the status of procurement activities for the Transmission Line.

  19. Brown spider dermonecrotic toxin directly induces nephrotoxicity

    International Nuclear Information System (INIS)

    Chaim, Olga Meiri; Sade, Youssef Bacila; Bertoni da Silveira, Rafael; Toma, Leny; Kalapothakis, Evanguedes; Chavez-Olortegui, Carlos; Mangili, Oldemir Carlos; Gremski, Waldemiro; Dietrich, Carl Peter von; Nader, Helena B.; Sanches Veiga, Silvio

    2006-01-01

    Brown spider (Loxosceles genus) venom can induce dermonecrotic lesions at the bite site and systemic manifestations including fever, vomiting, convulsions, disseminated intravascular coagulation, hemolytic anemia and acute renal failure. The venom is composed of a mixture of proteins with several molecules biochemically and biologically well characterized. The mechanism by which the venom induces renal damage is unknown. By using mice exposed to Loxosceles intermedia recombinant dermonecrotic toxin (LiRecDT), we showed direct induction of renal injuries. Microscopic analysis of renal biopsies from dermonecrotic toxin-treated mice showed histological alterations including glomerular edema and tubular necrosis. Hyalinization of tubules with deposition of proteinaceous material in the tubule lumen, tubule epithelial cell vacuoles, tubular edema and epithelial cell lysis was also observed. Leukocytic infiltration was neither observed in the glomerulus nor the tubules. Renal vessels showed no sign of inflammatory response. Additionally, biochemical analyses showed such toxin-induced changes in renal function as urine alkalinization, hematuria and azotemia with elevation of blood urea nitrogen levels. Immunofluorescence with dermonecrotic toxin antibodies and confocal microscopy analysis showed deposition and direct binding of this toxin to renal intrinsic structures. By immunoblotting with a hyperimmune dermonecrotic toxin antiserum on renal lysates from toxin-treated mice, we detected a positive signal at the region of 33-35 kDa, which strengthens the idea that renal failure is directly induced by dermonecrotic toxin. Immunofluorescence reaction with dermonecrotic toxin antibodies revealed deposition and binding of this toxin directly in MDCK epithelial cells in culture. Similarly, dermonecrotic toxin treatment caused morphological alterations of MDCK cells including cytoplasmic vacuoles, blebs, evoked impaired spreading and detached cells from each other and from

  20. Two-Spotted Ladybeetle Adalia bipunctata L. (Coleoptera: Coccinellidae): A Commercially Available Predator to Control Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Khan, Azhar A; Qureshi, Jawwad A; Afzal, Muhammad; Stansly, Philip A

    2016-01-01

    The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an economically important pest of citrus because it serves as a vector of the causal pathogens of huanglongbing (HLB) also known as citrus greening disease. The increased use of insecticides for control of D. citri negatively impacts several natural enemies including some effective ladybeetle species which are not available commercially. The two-spotted ladybeetle, Adalia bipunctata (Coleoptera: Coccinellidae) is found in some crop and forest ecosystems of Asia, Europe and North America and available commercially. It is known to attack aphids and mealybugs but there are no published records of feeding on psyllids. We evaluated suitability and preference of A. bipunctata for nymphs of D. citri compared to corn leaf aphid Rhopalosiphum maidis (Hemiptera: Aphididae) a global pest of cereal crops and prey for many predaceous insects. We also compared development and reproduction of A. bipunctata on these two species with frozen eggs of the Mediterranean flour moth Ephestia kuehniella (Lepidoptera: Pyralidae) at 25°C. Initially, more D. citri than R. maidis nymphs were consumed in the no-choice tests although final consumption by larva and adult of A. bipunctata did not differ in the choice and no-choice tests. Larval development was prolonged by one day on D. citri compared to R. maidis nymphs but did not differ between either of these diets and E. kuehniella. Larval survival to adult averaged 93-100% and was not impacted by diet. Adult life span did not differ between diets although those on D. citri and R. maidis nymphs weighed less and produced fewer but more fertile eggs than on E. kuehniella eggs. Significant reduction of D. citri nymphs averaging 54% was observed in colonies caged with adult A. bipunctata on field planted citrus. R° (net reproductive rate) was least for beetles fed R. maidis, but otherwise there were no significant differences in demographic parameters. Successful

  1. Assassin bug uses aggressive mimicry to lure spider prey.

    Science.gov (United States)

    Wignall, Anne E; Taylor, Phillip W

    2011-05-07

    Assassin bugs (Stenolemus bituberus) hunt web-building spiders by invading the web and plucking the silk to generate vibrations that lure the resident spider into striking range. To test whether vibrations generated by bugs aggressively mimic the vibrations generated by insect prey, we compared the responses of spiders to bugs with how they responded to prey, courting male spiders and leaves falling into the web. We also analysed the associated vibrations. Similar spider orientation and approach behaviours were observed in response to vibrations from bugs and prey, whereas different behaviours were observed in response to vibrations from male spiders and leaves. Peak frequency and duration of vibrations generated by bugs were similar to those generated by prey and courting males. Further, vibrations from bugs had a temporal structure and amplitude that were similar to vibrations generated by leg and body movements of prey and distinctly different to vibrations from courting males or leaves, or prey beating their wings. To be an effective predator, bugs do not need to mimic the full range of prey vibrations. Instead bugs are general mimics of a subset of prey vibrations that fall within the range of vibrations classified by spiders as 'prey'.

  2. Cuticular antifungals in spiders: density- and condition dependence.

    Directory of Open Access Journals (Sweden)

    Daniel González-Tokman

    Full Text Available Animals living in groups face a high risk of disease contagion. In many arthropod species, cuticular antimicrobials constitute the first protective barrier that prevents infections. Here we report that group-living spiders produce cuticular chemicals which inhibit fungal growth. Given that cuticular antifungals may be costly to produce, we explored whether they can be modulated according to the risk of contagion (i.e. under high densities. For this purpose, we quantified cuticular antifungal activity in the subsocial crab spider Diaea ergandros in both natural nests and experimentally manipulated nests of varying density. We quantified the body-condition of spiders to test whether antifungal activity is condition dependent, as well as the effect of spider density on body-condition. We predicted cuticular antifungal activity to increase and body-condition to decrease with high spider densities, and that antifungal activity would be inversely related to body-condition. Contrary to our predictions, antifungal activity was neither density- nor condition-dependent. However, body-condition decreased with density in natural nests, but increased in experimental nests. We suggest that pathogen pressure is so important in nature that it maintains high levels of cuticular antifungal activity in spiders, impacting negatively on individual energetic condition. Future studies should identify the chemical structure of the isolated antifungal compounds in order to understand the physiological basis of a trade-off between disease prevention and energetic condition caused by group living, and its consequences in the evolution of sociality in spiders.

  3. Silk elasticity as a potential constraint on spider body size.

    Science.gov (United States)

    Rodríguez-Gironés, Miguel A; Corcobado, Guadalupe; Moya-Laraño, Jordi

    2010-10-07

    Silk is known for its strength and extensibility and has played a key role in the radiation of spiders. Individual spiders use different glands to produce silk types with unique sets of proteins. Most research has studied the properties of major ampullate and capture spiral silks and their ecological implications, while little is known about minor ampullate silk, the type used by those spider species studied to date for bridging displacements. A biomechanical model parameterised with available data shows that the minimum radius of silk filaments required for efficient bridging grows with the square root of the spider's body mass, faster than the radius of minor ampullate silk filaments actually produced by spiders. Because the morphology of spiders adapted to walking along or under silk threads is ill suited for moving on a solid surface, for these species there is a negative relationship between body mass and displacement ability. As it stands, the model suggests that spiders that use silk for their displacements are prevented from attaining a large body size if they must track their resources in space. In particular, silk elasticity would favour sexual size dimorphism because males that must use bridging lines to search for females cannot grow large. 2010 Elsevier Ltd. All rights reserved.

  4. Cuticular antifungals in spiders: density- and condition dependence.

    Science.gov (United States)

    González-Tokman, Daniel; Ruch, Jasmin; Pulpitel, Tamara; Ponton, Fleur

    2014-01-01

    Animals living in groups face a high risk of disease contagion. In many arthropod species, cuticular antimicrobials constitute the first protective barrier that prevents infections. Here we report that group-living spiders produce cuticular chemicals which inhibit fungal growth. Given that cuticular antifungals may be costly to produce, we explored whether they can be modulated according to the risk of contagion (i.e. under high densities). For this purpose, we quantified cuticular antifungal activity in the subsocial crab spider Diaea ergandros in both natural nests and experimentally manipulated nests of varying density. We quantified the body-condition of spiders to test whether antifungal activity is condition dependent, as well as the effect of spider density on body-condition. We predicted cuticular antifungal activity to increase and body-condition to decrease with high spider densities, and that antifungal activity would be inversely related to body-condition. Contrary to our predictions, antifungal activity was neither density- nor condition-dependent. However, body-condition decreased with density in natural nests, but increased in experimental nests. We suggest that pathogen pressure is so important in nature that it maintains high levels of cuticular antifungal activity in spiders, impacting negatively on individual energetic condition. Future studies should identify the chemical structure of the isolated antifungal compounds in order to understand the physiological basis of a trade-off between disease prevention and energetic condition caused by group living, and its consequences in the evolution of sociality in spiders.

  5. Size of predatory mites and refuge entrance determine success of biological control of the coconut mite

    NARCIS (Netherlands)

    da Silva, F.R.; de Moraes, G.J.; Lesna, I.; Sato, Y.; Vasquez, C.; Hanna, R.; Sabelis, M.W.; Janssen, A.

    2016-01-01

    Predators face the challenge of accessing prey that live in sheltered habitats. The coconut mite Aceriaguerreronis Keifer (Acari: Eriophyidae) lives hidden beneath the perianth, which is appressed to the coconut fruit surface, where they feed on the meristematic tissue. Its natural enemy, the

  6. Bee Mite ID - an online resource on identification of mites associated with bees of the World

    Science.gov (United States)

    Parasitic mites are known to be a factor in recent declines in bee pollinator populations. In particular, Varroa destructor, an introduced parasite and disease vector, has decimated colonies of the western honey bee, one of the most important agricultural pollinators in the world. Further, global tr...

  7. Invasion of Varroa mites into honey bee brood cells

    NARCIS (Netherlands)

    Boot, W.J.

    1995-01-01

    The parasitic mite Varroa-jacobsoni is one of the most serious pests of Western honey bees, Apis mellifera. The mites parasitize adult bees, but reproduction only occurs while parasitizing on honey bee brood. Invasion into a

  8. House dust mites in the city of Lima, Peru.

    Science.gov (United States)

    Croce, M; Costa-Manso, E; Baggio, D; Croce, J

    2000-01-01

    Since mites are the most common house dust allergens, knowledge about the species most prevalent in a region is important for diagnostic and specific immunotherapy purposes. In order to establish the prevalence of house dust mites in different city districts, 100 house dust samples were collected from different parts of Lima. Lima is a city of tropical climate located along the coast of the Pacific Ocean. The relative air humidity is 80-90% and the various districts studied are located at altitudes ranging from 37-355 meters. The mite Blomia tropicalis was the organism most frequently detected, being present in 59% of the house dust samples. Dermatophagoides pteronyssinus occupied second place (15.9%), followed by Chortoglyphus arcuatus and Tyrophagus putrescentiae. These four mites, taken together, represented more than 90% of the mites detected. No specimen of the species Dermatophagoides farinae was detected. We conclude that B. tropicalis and D. pteronyssinus are the most common house dust mites in Lima. Considering the high prevalence of B. tropicalis in Lima and the fact that its cross-reactivity with antigens of the mites of the family Pyroglyphidae is minimal, we conclude that sensitization to this mite should be investigated separately in allergic patients living in Lima.

  9. Mite Biodiversity Under the Low Temperature Scanning Electron Microscope

    Science.gov (United States)

    To date, more than 55,000 mite species have been described and only a few of them have been studied. Some mites are adapted to live deep in soil, others in fresh or sea water, some are on plants, algae, fungi or animals, and others are able to survive in both extreme cold and hot temperatures. The...

  10. Ecology, life history and management of tropilaelaps mites

    Science.gov (United States)

    Parasitic mites are the major threat of the Western honey bee, Apis mellifera. For much of the world, Varroa destructor single-handedly inflicts unsurmountable problems to A. mellifera beekeeping. However, A. mellifera in Asia is also faced with another genus of destructive parasitic mite, Tropilae...

  11. The Tropilaelaps mites threat: Observations of their reproductive success

    Science.gov (United States)

    Tropilaelaps spp. are more successful parasitic mites of Apis mellifera than Varroa destructor in Asia (Burgett et al., Bee World 64:25-28). We sought explanations to this success by assessing their fecundity on European bees in three short experiments using the mite transfer technique: 1) fecundity...

  12. IPM potentials of microbial pathogens and diseases of mites

    NARCIS (Netherlands)

    van der Geest, L.P.S.; Ciancio, A.; Mukerji, K.G.

    2010-01-01

    An overview is given of diseases in mites, caused by infectious microorganisms. Many pathogens play an important role in the regulation of natural populations of mite populations and are for this reason subject of research on the feasibility to develop such pathogens to biological control agents.

  13. Resistance of the predacious mite, euseius kenyae (acari ...

    African Journals Online (AJOL)

    This study was carried out to assess whether the predacious phytoseiid mite, Euseius kenyae (Swirski and Ragusa), commonly found in major coffee growing regions in Kenya has developed resistance to Chlorpyrifos. Mite populations were collected from coffee farms harbouring E. kenyae and where Chlorpyrifos or other ...

  14. First report of clinical presentation of a bite by a running spider, Philodromus sp. (Araneae: Philodromidae), with recommendations for spider bite management.

    Science.gov (United States)

    Coetzee, Maureen; Dippenaar, Ansie; Frean, John; Hunt, Richard H

    2017-06-30

    This article describes the clinical progression of symptoms over a period of 5 days of a bite inflicted by a Philodromus sp. spider. Commonly known as 'running spiders', these are not considered to be harmful to humans. This report, however, is the first description of an actual bite by a member of this group of spiders showing cytotoxic envenomation. Management of the bites should be as recommended for other cytotoxic spider bites.

  15. Structure-function-property-design interplay in biopolymers: spider silk.

    Science.gov (United States)

    Tokareva, Olena; Jacobsen, Matthew; Buehler, Markus; Wong, Joyce; Kaplan, David L

    2014-04-01

    Spider silks have been a focus of research for almost two decades due to their outstanding mechanical and biophysical properties. Recent advances in genetic engineering have led to the synthesis of recombinant spider silks, thus helping to unravel a fundamental understanding of structure-function-property relationships. The relationships between molecular composition, secondary structures and mechanical properties found in different types of spider silks are described, along with a discussion of artificial spinning of these proteins and their bioapplications, including the role of silks in biomineralization and fabrication of biomaterials with controlled properties. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Inhibition of the spider heartbeat by gravity and vibration

    Science.gov (United States)

    Finck, A.

    1984-01-01

    The rate and vigor of the spider heartbeat is controlled by an external pacemaker. A mechanical feature of the spider cardio-vascular system is the production of high serum pressure in the prosoma and the legs. This appears to be the source for leg extension. The lyriform organ on the patella of the leg is sensitive to vibratory and kinesthetic stimuli. This sensitivity depends upon the degree of leg extension. Thus the activity of the heart and the response characteristics of the sense receptor are related. The effect of a supra-threshold vibratory or gravitational stimulus is to produce an inhibition and a tachycardia of the spider heartbeat.

  17. Spider silk reinforced by graphene or carbon nanotubes

    Science.gov (United States)

    Lepore, Emiliano; Bosia, Federico; Bonaccorso, Francesco; Bruna, Matteo; Taioli, Simone; Garberoglio, Giovanni; Ferrari, Andrea C.; Pugno, Nicola Maria

    2017-09-01

    Spider silk has promising mechanical properties, since it conjugates high strength (~1.5 GPa) and toughness (~150 J g-1). Here, we report the production of silk incorporating graphene and carbon nanotubes by spider spinning, after feeding spiders with the corresponding aqueous dispersions. We observe an increment of the mechanical properties with respect to pristine silk, up to a fracture strength ~5.4 GPa and a toughness modulus ~1570 J g-1. This approach could be extended to other biological systems and lead to a new class of artificially modified biological, or ‘bionic’, materials.

  18. Colonization of subterranean habitats by spiders in Central Europe

    Directory of Open Access Journals (Sweden)

    Vlastimil Růžička

    2013-05-01

    Full Text Available Using data from the Czech Republic, we studied the distribution of spiders in soils, crevice systems, scree and caves, i.e. subterranean habitats at depths spanning from 10 cm to 100 m. In total, we found 161 species. The number of species declines with increasing habitat depth, with a major drop in species richness at the depth of 10 meters. Thirteen species exhibit morphological adaptations to life in subterranean habitats. At depths greater than 10 meters, spider assemblages are almost exclusively composed of troglomorphic species. We propose a hypothesis of evolution of troglomorphisms at spiders during Quaternary climatic cycles.

  19. Large-bodied Demodex mite infestation in 4 dogs.

    Science.gov (United States)

    Hillier, Andrew; Desch, Clifford E

    2002-03-01

    Large-bodied Demodex mites were detected in 4 dogs. The mites were readily detected in material obtained via deep skin scrapings and were most commonly found on the trunk. The mites were distinguishable from D. canis, because adult males were approximately 100% longer and adult females were approximately 50% longer than adult male and female D. canis mites, respectively. The large-bodied mites were found in the hair follicles, sebaceous ducts, and sebaceous glands in histologic sections of skin from 2 dogs. All dogs had adult-onset generalized demodicosis. Two dogs had coexistent iatrogenic hypercortisolism, 1 dog had hypothyroidism, and 1 dog did not have coexistent disease. Infestations responded to miticidal therapy, control of the coexistent disease, or both.

  20. Mites (acari) infesting commensal rats in Suez Canal zone, Egypt.

    Science.gov (United States)

    el Kady, G A; Shoukry, A; Ragheb, D A; el Said, A M; Habib, K S; Morsy, T A

    1995-08-01

    Mites are arthropods distinguished from ticks by usually being microscopical in size and have a hypostome unarmed with tooth-like anchoring processes. They are group in a number of suborders, each with super-families and families including many genera of medical and economic importance. In this paper, commensal rodents (Rattus norvegicus, R. r. alexandrinus and R. r. frugivorous) were surveyed in the Suez Canal Zone for their acari ectoparasites. Four species of mites were recovered. In a descending order of mite indices, they were Eulaelaps stabularis (4.83 on 6 rats), Laelaps nuttalli (3.11 on 27 rats), Ornithonyssus bacoti (1.66 on 9 rats) and Dermanyssus gallinae (0.66 on 24 rats). The overall mite indices in the three governorates were 3.66 in Suez, 2.82 in Ismailia and zero in Port Said. The medical and economic importance of the mites were discussed.

  1. Venomous snake bites, scorpions, and spiders.

    Science.gov (United States)

    Kularatne, S A M; Senanayake, Nimal

    2014-01-01

    Neurologic dysfunction due to natural neurotoxins is an important, but neglected, public health hazard in many parts of the world, particularly in the tropics. These toxins are produced by or found among a variety of live forms that include venomous snakes, arthropods such as scorpions, spiders, centipedes, stinging insects (Hymenoptera), ticks, certain poisonous fish, shellfish, crabs, cone shells, skin secretions of dart-poison frogs, and bacterial poisons such as botulinum toxin. These toxins commonly act on neuromuscular transmission at the neuromuscular junction where acetylcholine is the neurotransmitter, but in certain situations the toxins interfere with neurotransmitters such as GABA, noradrenaline, adrenaline, dopamine, and γ-aminobutyrate. Of the toxins, α-toxins and κ-toxins (e.g., Chinese krait, Bungarus multicinctus) act on the postsynaptic membrane, blocking the receptors, whilst β-toxin (e.g., common krait, B. caeruleus) acts on the presynaptic membrane, causing impairment of acetylcholine release. Conversely, dendrotoxins of the African mamba enhance acetylcholine release. The toxins of scorpions and spiders commonly interfere with voltage-gated ion channels. Clinically, the cardinal manifestation is muscle paralysis. In severe cases respiratory paralysis could be fatal. Effective antivenoms are the mainstay of treatment of envenoming, but their lack of availability is the major concern in the regions of the globe where they are desperately needed. Interestingly, some toxins have proved to be valuable pharmaceutical agents, while some others are widely exploited to study neuromuscular physiology and pathology. © 2014 Elsevier B.V. All rights reserved.

  2. Free amino acids in spider hemolymph.

    Science.gov (United States)

    Tillinghast, Edward K; Townley, Mark A

    2008-11-01

    We examined the free amino acid composition of hemolymph from representatives of five spider families with an interest in knowing if the amino acid profile in the hemolymph of orb-web-building spiders reflects the high demands for small organic compounds in the sticky droplets of their webs. In nearly all analyses, on both orb and non-orb builders, glutamine was the most abundant free amino acid. Glycine, taurine, proline, histidine, and alanine also tended to be well-represented in orb and non-orb builders. While indications of taxon-specific differences in amino acid composition were observed, it was not apparent that two presumptive precursors (glutamine, taurine) of orb web sticky droplet compounds were uniquely enriched in araneids (orb builders). However, total amino acid concentrations were invariably highest in the araneids and especially so in overwintering juveniles, even as several of the essential amino acids declined during this winter diapause. Comparing the data from this study with those from earlier studies revealed a number of discrepancies. The possible origins of these differences are discussed.

  3. Intracellular recording from a spider vibration receptor.

    Science.gov (United States)

    Gingl, Ewald; Burger, Anna-M; Barth, Friedrich G

    2006-05-01

    The present study introduces a new preparation of a spider vibration receptor that allows intracellular recording of responses to natural mechanical or electrical stimulation of the associated mechanoreceptor cells. The spider vibration receptor is a lyriform slit sense organ made up of 21 cuticular slits located on the distal end of the metatarsus of each walking leg. The organ is stimulated when the tarsus receives substrate vibrations, which it transmits to the organ's cuticular structures, reducing the displacement to about one tenth due to geometrical reasons. Current clamp recording was used to record action potentials generated by electrical or mechanical stimuli. Square pulse stimulation identified two groups of sensory cells, the first being single-spike cells which generated only one or two action potentials and the second being multi-spike cells which produced bursts of action potentials. When the more natural mechanical sinusoidal stimulation was applied, differences in adaptation rate between the two cell types remained. In agreement with prior extracellular recordings, both cell types showed a decrease in the threshold tarsus deflection with increasing stimulus frequency. Off-responses to mechanical stimuli have also been seen in the metatarsal organ for the first time.

  4. Spectral sensitivity of a colour changing spider.

    Science.gov (United States)

    Defrize, Jérémy; Lazzari, Claudio R; Warrant, Eric J; Casas, Jérôme

    2011-04-01

    Vision plays a paramount role in some spider families such as the Salticidae, Lycosidae and Thomisidae, as it is involved in prey hunting, orientation or choice of substrate. In the thomisid Misumena vatia, for which the substrate colour affects the body colour, vision seems to mediate morphological colour changes. However, nothing is known about which component of visual signals from the substrate might be perceived, nor whether M. vatia possesses the physiological basis for colour vision. The aim of this study is thus to investigate the vision of this spider species by measuring the spectral sensitivities of the different pairs of eyes using electrophysiological methods. Extra- and intracellular electrophysiological recordings combined with selective adaptation revealed the presence of two classes of photoreceptor cells, one sensitive in the UV region of the spectrum (around 340 nm) and one sensitive in the green (around 520 nm) regions in the four pairs of eyes. We conclude that M. vatia possesses the physiological potential to perceive both chromatic and achromatic components of the environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Spiders (Araneae) Found in Bananas and Other International Cargo Submitted to North American Arachnologists for Identification.

    Science.gov (United States)

    Vetter, Richard S; Crawford, Rodney L; Buckle, Donald J

    2014-11-01

    Spiders found in international cargo brought into North America are sometimes submitted to arachnologists for identification. Often, these spiders are presumed to be of medical importance because of size or a submitter's familiarity with a toxic spider genus from the continent of origin. Starting in 2006, requests were made for spiders found in international cargo brought into North America, in addition to the specimens from similar cargo shipments already in our museum collections. This was an ad hoc study that allowed us to focus on spiders of concern to the discoverer. We identified 135 spiders found in international cargo. A key for the most common species is provided. The most frequently submitted spiders were the pantropical huntsman spider, Heteropoda venatoria (L.) (Sparassidae), and the redfaced banana spider, Cupiennius chiapanensis Medina Soriano (Ctenidae). Spiders of medical importance were rare. The most common cargo from which spiders were submitted was bananas with most specimens coming from Central America, Ecuador, or Colombia. Lack of experience with nonnative fauna caused several experienced American arachnologists to misidentify harmless ctenid spiders (C. chiapanensis, spotlegged banana spider, Cupiennius getazi Simon) as highly toxic Phoneutria spiders. These misidentifications could have led to costly, unwarranted prophylactic eradication measures, unnecessary employee health education, heightened employee anxiety and spoilage when perishable goods are left unloaded due to safety concerns. © 2014 Entomological Society of America.

  6. Phylogenomics resolves a spider backbone phylogeny and rejects a prevailing paradigm for orb web evolution.

    Science.gov (United States)

    Bond, Jason E; Garrison, Nicole L; Hamilton, Chris A; Godwin, Rebecca L; Hedin, Marshal; Agnarsson, Ingi

    2014-08-04

    Spiders represent an ancient predatory lineage known for their extraordinary biomaterials, including venoms and silks. These adaptations make spiders key arthropod predators in most terrestrial ecosystems. Despite ecological, biomedical, and biomaterial importance, relationships among major spider lineages remain unresolved or poorly supported. Current working hypotheses for a spider "backbone" phylogeny are largely based on morphological evidence, as most molecular markers currently employed are generally inadequate for resolving deeper-level relationships. We present here a phylogenomic analysis of spiders including taxa representing all major spider lineages. Our robust phylogenetic hypothesis recovers some fundamental and uncontroversial spider clades, but rejects the prevailing paradigm of a monophyletic Orbiculariae, the most diverse lineage, containing orb-weaving spiders. Based on our results, the orb web either evolved much earlier than previously hypothesized and is ancestral for a majority of spiders or else it has multiple independent origins, as hypothesized by precladistic authors. Cribellate deinopoid orb weavers that use mechanically adhesive silk are more closely related to a diverse clade of mostly webless spiders than to the araneoid orb-weaving spiders that use adhesive droplet silks. The fundamental shift in our understanding of spider phylogeny proposed here has broad implications for interpreting the evolution of spiders, their remarkable biomaterials, and a key extended phenotype--the spider web. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Clinical evaluation of a double-blind dust mite avoidance trial with mite-allergic rhinitic patients

    NARCIS (Netherlands)

    Kniest, F.M.; Young, E.; Praag, van M.C.G.; Vos, H.; Kort, H.S.M.; Koers, W.J.; Maat-Bleeker, de F.; Bronswijk, van J.E.M.H.

    1991-01-01

    Inheritance and allergen exposure are key factors in the development and the course of atopic allergy, expressed as conjunctivitis, rhinitis, asthma or dermatitis. This study concerns the clinical significance of mite and mite-allergen avoidance measures based on intensive cleaning with acaricide

  8. Mechanisms and patient compliance of dust-mite avoidance regimens in dwellings of mite-allergic rhinitic patients

    NARCIS (Netherlands)

    Kniest, F.M.; Wolfs, B.G.; Vos, H.; Ducheine, B.O.I.; Schayk-Bakker, M.J.; de Lange, P.J.P.; Vos, E.M.P.; Bronswijk, van J.E.M.H.

    1992-01-01

    We report on the mechanisms, the environmental changes and patient compliance with regard to conventional and new dust and mite avoidance measures to prevent allergic symptoms caused by mite allergens, taking into account both allergen contamination and the developmental success of pyroglyphid

  9. Vision in the nocturnal wandering spider Leucorchestris arenicola (Araneae: Sparassidae)

    DEFF Research Database (Denmark)

    Nørgaard, Thomas; Nilsson, Dan-Eric; Henschel, Joh R

    2008-01-01

    At night the Namib Desert spider Leucorchestris arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders' eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role...... in the posterior and anteriomedian eyes, and at approximately 540 nm in the anteriolateral eyes. Theoretical calculations of photon catches showed that the eyes are likely to employ a combination of spatial and temporal pooling in order to function at night. Under starlit conditions, the raw spatial and temporal...... resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L...

  10. 46 SPIDER WEBS AS INDICATORS OF COBALT AND LEAD ...

    African Journals Online (AJOL)

    Spider webs were collected from the indoor and outdoor of 120 sampling sites of 10 zones of Kano ... diet, cobalt containing ceramic is administered into ... significant human and environmental health risk. ..... Evaluation of Health Workers.

  11. Optical surface profiling of orb-web spider capture silks

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D M; Joyce, A M; Staib, G R [Department of Physics, Macquarie University, Sydney, NSW 2109 (Australia); Herberstein, M E, E-mail: deb.kane@mq.edu.a [Department of Biological Sciences, Macquarie University, Sydney, NSW 2109 (Australia)

    2010-09-15

    Much spider silk research to date has focused on its mechanical properties. However, the webs of many orb-web spiders have evolved for over 136 million years to evade visual detection by insect prey. It is therefore a photonic device in addition to being a mechanical device. Herein we use optical surface profiling of capture silks from the webs of adult female St Andrews cross spiders (Argiope keyserlingi) to successfully measure the geometry of adhesive silk droplets and to show a bowing in the aqueous layer on the spider capture silk between adhesive droplets. Optical surface profiling shows geometric features of the capture silk that have not been previously measured and contributes to understanding the links between the physical form and biological function. The research also demonstrates non-standard use of an optical surface profiler to measure the maximum width of a transparent micro-sized droplet (microlens).

  12. Biotechnological Trends in Spider and Scorpion Antivenom Development

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Solà, Mireia; Jappe, Emma Christine

    2016-01-01

    in using bioactive toxins from spiders and scorpions for drug discovery purposes and for solving crystal structures of membrane-embedded receptors. Additionally, the identification and isolation of a myriad of spider and scorpion toxins has allowed research within next generation antivenoms to progress...... at an increasingly faster pace. In this review, the current knowledge of spider and scorpion venoms is presented, followed by a discussion of all published biotechnological efforts within development of spider and scorpion antitoxins based on small molecules, antibodies and fragments thereof, and next generation...... immunization strategies. The increasing number of discovery and development efforts within this field may point towards an upcoming transition from serum-based antivenoms towards therapeutic solutions based on modern biotechnology....

  13. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    NARCIS (Netherlands)

    Yang, Liang; Hedhammar, My; Blom, Tobias; Leifer, Klaus; Johansson, Jan; Habibovic, Pamela; van Blitterswijk, Clemens

    2010-01-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently,

  14. Peculiar torsion dynamical response of spider dragline silk

    Science.gov (United States)

    Liu, Dabiao; Yu, Longteng; He, Yuming; Peng, Kai; Liu, Jie; Guan, Juan; Dunstan, D. J.

    2017-07-01

    The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk.

  15. Optical surface profiling of orb-web spider capture silks

    International Nuclear Information System (INIS)

    Kane, D M; Joyce, A M; Staib, G R; Herberstein, M E

    2010-01-01

    Much spider silk research to date has focused on its mechanical properties. However, the webs of many orb-web spiders have evolved for over 136 million years to evade visual detection by insect prey. It is therefore a photonic device in addition to being a mechanical device. Herein we use optical surface profiling of capture silks from the webs of adult female St Andrews cross spiders (Argiope keyserlingi) to successfully measure the geometry of adhesive silk droplets and to show a bowing in the aqueous layer on the spider capture silk between adhesive droplets. Optical surface profiling shows geometric features of the capture silk that have not been previously measured and contributes to understanding the links between the physical form and biological function. The research also demonstrates non-standard use of an optical surface profiler to measure the maximum width of a transparent micro-sized droplet (microlens).

  16. SPIDER: Probing the dawn of time from above the clouds

    Science.gov (United States)

    Moncelsi, Lorenzo; Spider Collaboration

    2017-11-01

    SPIDER is a balloon-borne microwave polarimeter designed to measure cosmological B-modes on degree angular scales in the presence of Galactic foregrounds. With six independent telescopes housing a total of 2000 detectors in the 90 GHz and 150 GHz frequency bands, SPIDER is the most instantaneously-sensitive CMB polarimeter deployed on the sky to date. SPIDER was successfully launched from McMurdo Station, Antarctica in January 2015 and acquired science data for 16 days. We cover the in-flight performance and present highlights from the ongoing data-analysis. After a successful recovery, the SPIDER team is planning the next flight, featuring one foreground-optimized channel at 280GHz, which will allow us constrain the primordial tensor-mode amplitude at the level of r < 0.03 (99% CL), in the presence of foregrounds.

  17. Evolution of stenophagy in spiders (Araneae): evidence based on the comparative analysis of spider diets.

    Science.gov (United States)

    Pekár, Stano; Coddington, Jonathan A; Blackledge, Todd A

    2012-03-01

    Stenophagy (narrow diet breadth) represents an extreme of trophic specialization in carnivores, but little is known about the forces driving its evolution. We used spiders, the most diversified group of terrestrial predators, to investigate whether stenophagy (1) promoted diversification; (2) was phylogenetically conserved and evolutionarily derived state; and (3) was determined either by geographical distribution and foraging guild. We used published data on the prey of almost 600 species. Six categories of stenophagy were found: myrmecophagy, araneophagy, lepidopterophagy, termitophagy, dipterophagy, and crustaceophagy. We found that the species diversity of euryphagous genera and families was similar to stenophagous genera and families. At the family level, stenophagy evolved repeatedly and independently. Within families, the basal condition was oligophagy or euryphagy. Most types of stenophagy were clearly derived: myrmecophagy in Zodariidae; lepidopterophagy in Araneidae; dipterophagy in Theridiidae. In contrast, araneophagy was confined to basal and intermediate lineages, suggesting its ancestral condition. The diet breadth of species from the tropics and subtropics was less diverse than species from the temperate zone. Diet breadth was lower in cursorial spiders compared to web-building species. Thus, the evolution of stenophagy in spiders appears to be complex and governed by phylogeny as well as by ecological determinants. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  18. Thin Film Assembly of Spider Silk-like Block Copolymers

    Science.gov (United States)

    2011-01-01

    Shipley, N. H.; Lewis, R. V. Int. J. Biol.Macromol. 1999, 24, 271. (c) Thiel, B. L.; Guess, K. B.; Viney, C. Biopolymers 1997, 41, 703. (13) Silk ...Film Assembly of Spider Silk -like Block Copolymers Sreevidhya T. Krishnaji,†,‡ Wenwen Huang,§ Olena Rabotyagova,†,‡ Eugenia Kharlampieva, ) Ikjun Choi...Received November 26, 2010 We report the self-assembly of monolayers of spider silk -like block copolymers. Langmuir isotherms were obtained for a series of

  19. Early events in the evolution of spider silk genes.

    Directory of Open Access Journals (Sweden)

    James Starrett

    Full Text Available Silk spinning is essential to spider ecology and has had a key role in the expansive diversification of spiders. Silk is composed primarily of proteins called spidroins, which are encoded by a multi-gene family. Spidroins have been studied extensively in the derived clade, Orbiculariae (orb-weavers, from the suborder Araneomorphae ('true spiders'. Orbicularians produce a suite of different silks, and underlying this repertoire is a history of duplication and spidroin gene divergence. A second class of silk proteins, Egg Case Proteins (ECPs, is known only from the orbicularian species, Lactrodectus hesperus (Western black widow. In L. hesperus, ECPs bond with tubuliform spidroins to form egg case silk fibers. Because most of the phylogenetic diversity of spiders has not been sampled for their silk genes, there is limited understanding of spidroin gene family history and the prevalence of ECPs. Silk genes have not been reported from the suborder Mesothelae (segmented spiders, which diverged from all other spiders >380 million years ago, and sampling from Mygalomorphae (tarantulas, trapdoor spiders and basal araneomorph lineages is sparse. In comparison to orbicularians, mesotheles and mygalomorphs have a simpler silk biology and thus are hypothesized to have less diversity of silk genes. Here, we present cDNAs synthesized from the silk glands of six mygalomorph species, a mesothele, and a non-orbicularian araneomorph, and uncover a surprisingly rich silk gene diversity. In particular, we find ECP homologs in the mesothele, suggesting that ECPs were present in the common ancestor of extant spiders, and originally were not specialized to complex with tubuliform spidroins. Furthermore, gene-tree/species-tree reconciliation analysis reveals that numerous spidroin gene duplications occurred after the split between Mesothelae and Opisthothelae (Mygalomorphae plus Araneomorphae. We use the spidroin gene tree to reconstruct the evolution of amino acid

  20. Ozone exposure triggers the emission of herbivore-induced plant volatiles, but does not disturb tritrophic signalling

    Energy Technology Data Exchange (ETDEWEB)

    Vuorinen, Terhi; Nerg, Anne-Marja; Holopainen, Jarmo K

    2004-09-01

    We evaluated the similarities between ozone-induced and mite-induced emission of volatile organic compounds (VOCs) from lima beans, and tested the response of the natural enemies of herbivores to these emissions using trophic system of two-spotted spider mites and predatory mites. The acute ozone-exposure and spider mite-infestation induced the emission of two homoterpenes, (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, and (Z)-3-hexenyl acetate. Only plants with spider mite-infestation emitted the monoterpene (E)-{beta}-ocimene. Predatory mites were equally attracted to ozone-exposed and unexposed plants, but discriminated between spider mite-infested and uninfested plants, when both were exposed to ozone. The similarities between ozone and herbivore-induced VOCs suggest that plant defence against phytotoxic ozone and the production of VOCs for attraction of the natural enemies of herbivores may have adaptive coevolution. However, the expected elevated ozone concentrations in future may not disturb tritrophic signalling, unless herbivore-induced VOCs are lost in the process of aerosol formation.

  1. Ozone exposure triggers the emission of herbivore-induced plant volatiles, but does not disturb tritrophic signalling

    International Nuclear Information System (INIS)

    Vuorinen, Terhi; Nerg, Anne-Marja; Holopainen, Jarmo K.

    2004-01-01

    We evaluated the similarities between ozone-induced and mite-induced emission of volatile organic compounds (VOCs) from lima beans, and tested the response of the natural enemies of herbivores to these emissions using trophic system of two-spotted spider mites and predatory mites. The acute ozone-exposure and spider mite-infestation induced the emission of two homoterpenes, (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, and (Z)-3-hexenyl acetate. Only plants with spider mite-infestation emitted the monoterpene (E)-β-ocimene. Predatory mites were equally attracted to ozone-exposed and unexposed plants, but discriminated between spider mite-infested and uninfested plants, when both were exposed to ozone. The similarities between ozone and herbivore-induced VOCs suggest that plant defence against phytotoxic ozone and the production of VOCs for attraction of the natural enemies of herbivores may have adaptive coevolution. However, the expected elevated ozone concentrations in future may not disturb tritrophic signalling, unless herbivore-induced VOCs are lost in the process of aerosol formation

  2. Cleaner mites: sanitary mutualism in the miniature ecosystem of neotropical bee nests.

    Science.gov (United States)

    Biani, Natalia B; Mueller, Ulrich G; Wcislo, William T

    2009-06-01

    Cleaning symbioses represent classic models of mutualism, and some bee mites are thought to perform cleaning services for their hosts in exchange for suitable environments for reproduction and dispersal. These mutual benefits, however, have not been rigorously demonstrated. We tested the sanitary role of bee mites by correlating mite loads with fungal contamination in natural nests of Megalopta genalis and Megalopta ecuadoria and by experimentally manipulating mite loads in artificial cells with developing brood. Field observations revealed significant correlations between the presence of mites and the absence of fungi inside the brood cells, as well as between the absence of mites and increased bee mortality. Likewise, experimental brood cells with mites have fewer fungal colonies than do cells without mites. Field observations and experimental manipulations, therefore, provide clear evidence of the sanitary effect of mites in nests of Megalopta bees. This bee-mite association constitutes one of the few examples of terrestrial cleaning mutualisms.

  3. Global associations between birds and vane-dwelling feather mites.

    Science.gov (United States)

    Doña, Jorge; Proctor, Heather; Mironov, Sergey; Serrano, David; Jovani, Roger

    2016-11-01

    Understanding host-symbiont networks is a major question in evolutionary ecology. Birds host a great diversity of endo- and ectosymbiotic organisms, with feather mites (Arachnida: Acariformes: Analgoidea, Pterolichoidea) being among the most diverse of avian symbionts. A global approach to the ecology and evolution of bird-feather-mite associations has been hampered because of the absence of a centralized data repository. Here we present the most extensive data set of associations between feather mites and birds. Data include 12 036 records of 1887 feather mite species located on the flight feathers of 2234 bird species from 147 countries. Feather mites typically located inside quills, on the skin, or on downy body feathers are not included. Data were extracted from 493 published sources dating from 1882 to 2015. Data exploration shows that although most continents and bird families are represented, most bird species remain unexplored for feather mites. Nevertheless, this is the most comprehensive data set available for enabling global macroecological analyses of feather mites and their hosts, such as ecological network analyses. This metadata file outlines the structure of these data and provides primary references for all records used. © 2016 by the Ecological Society of America.

  4. Pheromonal Communication in the European House Dust Mite, Dermatophagoides pteronyssinus

    Directory of Open Access Journals (Sweden)

    Johannes L.M. Steidle

    2014-08-01

    Full Text Available Despite the sanitary importance of the European house dust mite Dermatophagoides pteronyssinus (Trouessart, 1897, the pheromonal communication in this species has not been sufficiently studied. Headspace analysis using solid phase micro extraction (SPME revealed that nerol, neryl formate, pentadecane, (6Z,9Z-6,9-heptadecadiene, and (Z-8-heptadecene are released by both sexes whereas neryl propionate was released by males only. Tritonymphs did not produce any detectable volatiles. In olfactometer experiments, pentadecane and neryl propionate were attractive to both sexes as well as to tritonymphs. (Z-8-heptadecene was only attractive to male mites. Therefore it is discussed that pentadecane and neryl propionate are aggregation pheromones and (Z-8-heptadecene is a sexual pheromone of the European house dust mite D. pteronyssinus. To study the potential use of pheromones in dust mite control, long-range olfactometer experiments were conducted showing that mites can be attracted to neryl propionate over distances of at least 50 cm. This indicates that mite pheromones might be useable to monitor the presence or absence of mites in the context of control strategies.

  5. Phoretic mites identified on andean hummingbirds (Trochilidae of Caldas, Colombia

    Directory of Open Access Journals (Sweden)

    Natalia López-Orozco

    Full Text Available Within the bird-plant-mite system, the relationship between hummingbirds, flowers, and mites remains poorly understood. In this study, we evaluated the degree of association between nasal mites and eight species of Andean hummingbirds in Colombia (Amazilia saucerrottei,A. tzacatl, Chalybura buffonii,Chlorostilbon mellisugus, Florisuga mellivora, Glaucis hirsutus, Phaethornis guy and P. striigularis. Over a five-month period (trapping effort 360 hours/month, a total of 178 birds were captured, from which 81 mite specimens were collected and identified as belonging to three genera (Proctolaelaps, Rhinoseius andTropicoseius spanning eleven species. This is the first report of its kind from Colombia on the identification of the mite speciesP. rabulatus, R. luteyni, R. rafinskii, T. berryi, T. colwelli, T. erro and T. uniformisand the first record of P. guy as phoretic host forProctolaelaps rabulatus. Morphological characteristics (length of the dorsal plate, width of the dorsal plate and setae z5 length alone failed to distinguish between mite species. The ecologic impact of this relationship on flowers with respect to nectar and pollen availability and the effect of mites on pollination by hummingbirds needs to be determined.

  6. Phoretic mites identified on Andean hummingbirds (Trochilidae) of Caldas, Colombia.

    Science.gov (United States)

    López-Orozco, Natalia; Cañón-Franco, William Alberto

    2013-01-01

    Within the bird-plant-mite system, the relationship between hummingbirds, flowers, and mites remains poorly understood. In this study, we evaluated the degree of association between nasal mites and eight species of Andean hummingbirds in Colombia (Amazilia saucerrottei, A. tzacatl, Chalybura buffonii, Chlorostilbon mellisugus, Florisuga mellivora, Glaucis hirsutus, Phaethornis guy and P. striigularis). Over a five-month period (trapping effort 360 hours/month), a total of 178 birds were captured, from which 81 mite specimens were collected and identified as belonging to three genera (Proctolaelaps, Rhinoseius and Tropicoseius) spanning eleven species. This is the first report of its kind from Colombia on the identification of the mite species P. rabulatus, R. luteyni, R. rafinskii, T. berryi, T. colwelli, T. erro and T. uniformis and the first record of P. guy as phoretic host for Proctolaelaps rabulatus. Morphological characteristics (length of the dorsal plate, width of the dorsal plate and setae z5 length) alone failed to distinguish between mite species. The ecologic impact of this relationship on flowers with respect to nectar and pollen availability and the effect of mites on pollination by hummingbirds needs to be determined.

  7. Early Cretaceous greenhouse pumped higher taxa diversification in spiders.

    Science.gov (United States)

    Shao, Lili; Li, Shuqiang

    2018-05-24

    The Cretaceous experienced one of the most remarkable greenhouse periods in geological history. During this time, ecosystem reorganizations significantly impacted the diversification of many groups of organisms. The rise of angiosperms marked a major biome turnover. Notwithstanding, relatively little remains known about how the Cretaceous global ecosystem impacted the evolution of spiders, which constitute one of the most abundant groups of predators. Herein, we evaluate the transcriptomes of 91 taxa representing more than half of the spider families. We add 23 newly sequenced taxa to the existing database to obtain a robust phylogenomic assessment. Phylogenetic reconstructions using different datasets and methods obtain novel placements of some groups, especially in the Synspermiata and the group having a retrolateral tibial apophysis (RTA). Molecular analyses indicate an expansion of the RTA clade at the Early Cretaceous with a hunting predatory strategy shift. Fossil analyses show a 7-fold increase of diversification rate at the same period, but this likely owes to the first occurrences spider in amber deposits. Additional analyses of fossil abundance show an accumulation of spider lineages in the Early Cretaceous. We speculate that the establishment of a warm greenhouse climate pumped the diversification of spiders, in particular among webless forms tracking the abundance of insect prey. Our study offers a new pathway for future investigations of spider phylogeny and diversification. Copyright © 2018. Published by Elsevier Inc.

  8. Impact of prescribed burning on a heathland inhabiting spider community

    Directory of Open Access Journals (Sweden)

    Krause, Rolf Harald

    2016-04-01

    Full Text Available Heathlands can provide refuge for many stenotopic and endangered arthropods, if habitat management practices are applied. A management measure that is rarely being used today, but which has the potential to support diversity of arthropod communities, is prescribed burning. In this study we investigated the effects of prescribed burning on spider assemblages on a burned site with Calluna vulgaris in the nature reserve Lueneburg Heath, northwest Germany. We used pitfall trapping with a sampling design of 39 traps over a period of one year and 17 sampling intervals on a burned and a control site. We compared overall species richness, activity abundance patterns and community composition of the two sites, with a particular focus on stenotopic and endangered species. We collected 5116 adult spiders and 99 species altogether in a relatively small sampling area. This number of species represents nearly one third of the regional species pool of heathland spider species. Twelve species occurred exclusively on the burned site in contrast to 28 species exclusively found on the unburned site. Although we found more than twice as many spider individuals and higher mean species richness on the control site than on the burned site, the species richness of red-listed spiders was higher on the burned site. Especially the fact that we found 24 endangered species on the burned site and only 20 on the control site indicates that the applied measure of prescribed burning can foster certain endangered spider species and contribute to preserving the overall biodiversity of heathland ecosystems.

  9. Nutrient Deprivation Induces Property Variations in Spider Gluey Silk

    Science.gov (United States)

    Blamires, Sean J.; Sahni, Vasav; Dhinojwala, Ali; Blackledge, Todd A.; Tso, I-Min

    2014-01-01

    Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition. PMID:24523902

  10. Phobic spider fear is associated with enhanced attentional capture by spider pictures: a rapid serial presentation event-related potential study.

    Science.gov (United States)

    Van Strien, Jan W; Franken, Ingmar H A; Huijding, Jorg

    2009-03-04

    The early posterior negativity (EPN) reflects early selective visual processing of emotionally significant information. This study explored the association between fear of spiders and the EPN for spider pictures. Fifty women completed a Spider Phobia Questionnaire and watched the random rapid serial presentation of 600 neutral, 600 negatively valenced emotional, and 600 spider pictures (three pictures per second). The EPN was scored as the mean activity in the 225-300-ms time window at lateral occipital electrodes. Participants with higher scores on the phobia questionnaire showed larger (i.e. more negative) EPN amplitudes in response to spider pictures. The results suggest that the attentional capture of spider-related stimuli is an automatic response, which is modulated by the extent of spider fear.

  11. Atomistic model of the spider silk nanostructure

    Science.gov (United States)

    Keten, Sinan; Buehler, Markus J.

    2010-04-01

    Spider silk is an ultrastrong and extensible self-assembling biopolymer that outperforms the mechanical characteristics of many synthetic materials including steel. Here we report atomic-level structures that represent aggregates of MaSp1 proteins from the N. Clavipes silk sequence based on a bottom-up computational approach using replica exchange molecular dynamics. We discover that poly-alanine regions predominantly form distinct and orderly beta-sheet crystal domains while disorderly structures are formed by poly-glycine repeats, resembling 31-helices. These could be the molecular source of the large semicrystalline fraction observed in silks, and also form the basis of the so-called "prestretched" molecular configuration. Our structures are validated against experimental data based on dihedral angle pair calculations presented in Ramachandran plots, alpha-carbon atomic distances, as well as secondary structure content.

  12. Free living astigmatid mites (Astigmatina): new taxa, rearing and use for mesostigmatid (Mesostigmata) predatory mite production

    OpenAIRE

    Marina Ferraz de Camargo Barbosa

    2016-01-01

    The cohort Astigmatina is divided in two major groups: Psoroptidia, composed mainly by feather and fur mites, and Non-psoroptidia, a dominant component of the acarofauna in ephemeral habitats. In these environments Astigmatina usually are saprophages or feed on fungi or bacteria. Astigmatina protonymphs undergo a complete reorganization of the body structure leading to the production of heteromorphic deutonymphs, generally specialized for dispersion through phoresy using arthropods and verteb...

  13. The phylogeny of fossil whip spiders.

    Science.gov (United States)

    Garwood, Russell J; Dunlop, Jason A; Knecht, Brian J; Hegna, Thomas A

    2017-04-21

    Arachnids are a highly successful group of land-dwelling arthropods. They are major contributors to modern terrestrial ecosystems, and have a deep evolutionary history. Whip spiders (Arachnida, Amblypygi), are one of the smaller arachnid orders with ca. 190 living species. Here we restudy one of the oldest fossil representatives of the group, Graeophonus anglicus Pocock, 1911 from the Late Carboniferous (Duckmantian, ca. 315 Ma) British Middle Coal Measures of the West Midlands, UK. Using X-ray microtomography, our principal aim was to resolve details of the limbs and mouthparts which would allow us to test whether this fossil belongs in the extant, relict family Paracharontidae; represented today by a single, blind species Paracharon caecus Hansen, 1921. Tomography reveals several novel and significant character states for G. anglicus; most notably in the chelicerae, pedipalps and walking legs. These allowed it to be scored into a phylogenetic analysis together with the recently described Paracharonopsis cambayensis Engel & Grimaldi, 2014 from the Eocene (ca. 52 Ma) Cambay amber, and Kronocharon prendinii Engel & Grimaldi, 2014 from Cretaceous (ca. 99 Ma) Burmese amber. We recovered relationships of the form ((Graeophonus (Paracharonopsis + Paracharon)) + (Charinus (Stygophrynus (Kronocharon (Charon (Musicodamon + Paraphrynus)))))). This tree largely reflects Peter Weygoldt's 1996 classification with its basic split into Paleoamblypygi and Euamblypygi lineages; we were able to score several of his characters for the first time in fossils. Our analysis draws into question the monophyly of the family Charontidae. Our data suggest that Graeophonus is a crown group amblypygid, and falls within a monophyletic Paleoamblypgi clade, but outside the family Paracharontidae (= Paracharonopsis + Paracharon). Our results also suggest a new placement for the Burmese amber genus Kronocharon, a node further down from its original position. Overall, we offer a

  14. The effects of, and interactions between, Cardinium and Wolbachia in the doubly infected spider mite Bryobia sarothamni (Acari: Tetranychidae)

    NARCIS (Netherlands)

    Ros, V.I.D.; Breeuwer, J.A.J.

    2009-01-01

    Many arthropods are infected with vertically transmitted, intracellular bacteria manipulating their host's reproduction. Cytoplasmic incompatibility (CI) is commonly observed and is expressed as a reduction in the number of offspring in crosses between infected males and uninfected females (or

  15. Riparian spiders as sentinels of PCB contamination across heterogeneous aquatic ecosystems

    Science.gov (United States)

    Riparian spiders are being used increasingly to track spatial patterns of contaminants in and fluxing from aquatic ecosystems. However, our understanding of the circumstances under which spiders are effective sentinels of aquatic pollution is limited. The present study tests the ...

  16. Detection methods for irradiated mites and insects

    International Nuclear Information System (INIS)

    Ignatowicz, S.

    1999-01-01

    Results of the study on the following tests for separation of irradiated pests from untreated ones are reported: (a) test for identification of irradiated mites (Acaridae) based on lack of fecundity of treated females; (b) test for identification of irradiated beetles based on their locomotor activity; (c) test for identification of irradiated pests based on electron spin resonance (ESR) signal derived from treated insects; (d) test for identification of irradiated pests based on changes in the midgut induced by gamma radiation; and (e) test for identification of irradiated pests based on the alterations in total proteins of treated adults. Of these detection methods, only the test based on the pathological changes induced by irradiation in the insect midgut may identify consistently either irradiated larvae or adults. This test is simple and convenient when a rapid processing technique for dehydrating and embedding the midgut is used. (author)

  17. Un mundo sin límites

    Directory of Open Access Journals (Sweden)

    Córdoba, Joaquín Mª

    2005-04-01

    Full Text Available A comienzos del siglo XVI, las nuevas ediciones del Atlas de Ptolomeo publicadas en Roma o Venecia solían incluir un mapamundi modificado sin cesara a medida que descubridores y navegantes alcanzaban nuevos y antes desconocidos horizontes. La temprana circunnavegación de Magallanes y Elcano (1519-1522 confirmaba con su esferidad, que el mundo no tenía límites. Durante aquel siglo magnífico, la literatura española de viajes al Oriente Próximo islámico tenía que ser menos señalada. La casi perenne guerra contra el Imperio Otomano, señor de una buena parte de las costas mediterráneas, y sobre todo la empresa de América y los viajes de exploración y conquista que aquella demandaba, …

  18. Research on Artificial Spider Web Model for Farmland Wireless Sensor Network

    OpenAIRE

    Jun Wang; Song Gao; Shimin Zhao; Guang Hu; Xiaoli Zhang; Guowang Xie

    2018-01-01

    Through systematic analysis of the structural characteristics and invulnerability of spider web, this paper explores the possibility of combining the advantages of spider web such as network robustness and invulnerability with farmland wireless sensor network. A universally applicable definition and mathematical model of artificial spider web structure are established. The comparison between artificial spider web and traditional networks is discussed in detail. The simulation result shows tha...

  19. Science 101: Why Don't Spiders Stick to Their Own Webs?

    Science.gov (United States)

    Robertson, Bill

    2011-01-01

    This article explains why spiders don't stick to their webs. Spiders don't get stuck in their own webs (and they aren't immune to their own glue) because they use a combination of sticky and nonsticky threads (different glands for producing those), and the glue is in droplets that the spider can avoid but the prey can't. The spider's nervous…

  20. Phenomenon of Rickettsiella phytoseiuli in Phytoseiulus persimilis mite.

    Science.gov (United States)

    Sutáková, G

    1994-01-01

    An unknown microorganism occurring in a predaceous mite Phytoseiulus persimilis was described by the author in 1977 as a new species Rickettsiella phytoseiuli. Some new results on the relation between this agent and its hosts are presented in this paper.

  1. Assessing hygienic behavior and attraction to Varroa mite (Acari ...

    African Journals Online (AJOL)

    user

    2011-02-07

    Feb 7, 2011 ... treatment and then the selected 5th instar larva were transferred to fundamental colonies with 10 to 12 ... Key words: Varroa mite, hygienic behavior (uncapping and .... into a container containing hot water and detergent.

  2. Genetic background of resistance to gall mite in Ribes species

    Directory of Open Access Journals (Sweden)

    Ingrida Mazeikiene

    2017-06-01

    Full Text Available Resistance to gall mite is an important genetic trait of Ribes. P and Ce genes, responsible for gall mite resistance, were established in Ribes species and interspecific hybrids using molecular markers. Resistance in R. americanum is determined by P gene and in R. sanguineum by Ce gene. Both molecular markers were absent in R. dikuscha genome. Molecular markers related to P and Ce genes were identified in the genome of R. aureum. Resistance to gall mite in the field conditions in R. nigrum x R. americanum, R. nigrum x R. aureum and R. nigrum x R. sanguineum F3 hybrids fitted an expected Mendelian segregation ratio of 1:1, 3:1 and 1:1, respectively. 75.0% of hybrids with a pyramidal resistance to gall mite carrying markers related to Ce and P genes were obtained in the cross combination R. nigrum x R. aureum and will be included in the future breeding programs.

  3. Ineffective crypsis in a crab spider: a prey community perspective.

    Science.gov (United States)

    Brechbühl, Rolf; Casas, Jérôme; Bacher, Sven

    2010-03-07

    Cryptic coloration is assumed to be beneficial to predators because of an increased encounter rate with unwary prey. This hypothesis is, however, very rarely, if ever, studied in the field. The aim of this study was to quantify the encounter rate and capture success of an ambush predator, in the field, as a function of its level of colour-matching with the background. We used the crab spider Misumena vatia, which varies its body colour and can thereby match the colour of the flower it hunts upon. We carried out a manipulative field experiment using a complete factorial design resulting in six different colour combinations of crab spiders and flowers differing in their degree of colour-matching. A rich and diverse set of naturally occurring insects visited the flowers while we continuously video-recorded the spider's foraging activity. This enabled us to test the crypsis, the spider avoidance and the flower visitor attraction hypotheses, all three supported by previous studies. Flower visitors of different groups either avoided crab spiders independent of colour-matching, such as solitary bees and syrphid flies, or ignored them, such as bumble-bees and honeybees. Moreover, colour-matched spiders did not have a higher encounter rate and capture success compared to the visually apparent ones. Thus, our results support the spider avoidance hypothesis, reject the two other hypotheses and uncovered a fourth behaviour: indifference to predators. Because flower visitors reacted differently, a community approach is mandatory in order to understand the function of background colour-matching in generalist predators. We discuss our results in relation to the size and sociality of the prey and in relation to the functional significance of colour change in this predator.

  4. Molecular Evolution of Spider Vision: New Opportunities, Familiar Players.

    Science.gov (United States)

    Morehouse, Nathan I; Buschbeck, Elke K; Zurek, Daniel B; Steck, Mireille; Porter, Megan L

    2017-08-01

    Spiders are among the world's most species-rich animal lineages, and their visual systems are likewise highly diverse. These modular visual systems, composed of four pairs of image-forming "camera" eyes, have taken on a huge variety of forms, exhibiting variation in eye size, eye placement, image resolution, and field of view, as well as sensitivity to color, polarization, light levels, and motion cues. However, despite this conspicuous diversity, our understanding of the genetic underpinnings of these visual systems remains shallow. Here, we review the current literature, analyze publicly available transcriptomic data, and discuss hypotheses about the origins and development of spider eyes. Our efforts highlight that there are many new things to discover from spider eyes, and yet these opportunities are set against a backdrop of deep homology with other arthropod lineages. For example, many (but not all) of the genes that appear important for early eye development in spiders are familiar players known from the developmental networks of other model systems (e.g., Drosophila). Similarly, our analyses of opsins and related phototransduction genes suggest that spider photoreceptors employ many of the same genes and molecular mechanisms known from other arthropods, with a hypothesized ancestral spider set of four visual and four nonvisual opsins. This deep homology provides a number of useful footholds into new work on spider vision and the molecular basis of its extant variety. We therefore discuss what some of these first steps might be in the hopes of convincing others to join us in studying the vision of these fascinating creatures.

  5. First report of clinical presentation of a bite by a running spider ...

    African Journals Online (AJOL)

    This article describes the clinical progression of symptoms over a period of 5 days of a bite inflicted by a Philodromus sp. spider. Commonly known as 'running spiders', these are not considered to be harmful to humans. This report, however, is the first description of an actual bite by a member of this group of spiders ...

  6. Salticid predation as one potential driving force of ant mimicry in jumping spiders

    Science.gov (United States)

    Huang, Jin-Nan; Cheng, Ren-Chung; Li, Daiqin; Tso, I-Min

    2011-01-01

    Many spiders possess myrmecomorphy, and species of the jumping spider genus Myrmarachne exhibit nearly perfect ant mimicry. Most salticids are diurnal predators with unusually high visual acuity that prey on various arthropods, including conspecifics. In this study, we tested whether predation pressure from large jumping spiders is one possible driving force of perfect ant mimicry in jumping spiders. The results showed that small non-ant-mimicking jumping spiders were readily treated as prey by large ones (no matter whether heterospecific or conspecific) and suffered high attack and mortality rates. The size difference between small and large jumping spiders significantly affected the outcomes of predatory interactions between them: the smaller the juvenile jumping spiders, the higher the predation risk from large ones. The attack and mortality rates of ant-mimicking jumping spiders were significantly lower than those of non-ant-mimicking jumping spiders, indicating that a resemblance to ants could provide protection against salticid predation. However, results of multivariate behavioural analyses showed that the responses of large jumping spiders to ants and ant-mimicking salticids differed significantly. Results of this study indicate that predation pressure from large jumping spiders might be one selection force driving the evolution of nearly perfect myrmecomorphy in spiders and other arthropods. PMID:20961898

  7. High School Students' Attitudes towards Spiders: A Cross-Cultural Comparison

    Science.gov (United States)

    Prokop, Pavol; Tolarovicova, Andrea; Camerik, Anne M.; Peterkova, Viera

    2010-01-01

    Spiders are traditionally considered to be among the least popular of animals. Current evidence suggests that a negative attitude towards spiders could be influenced by both cultural and evolutionary pressures. Some researchers suggest that science education activities could positively influence students' perceptions of spiders. Their evidence is,…

  8. Feather mites of Calidris fuscicollis (Aves: Scolopacidae) in Brazil

    OpenAIRE

    Gomes, S. N.; Pesenti, T. C.; Cirne, M. P.; Müller, G.

    2015-01-01

    Abstract During the period 2010-2012, eighty individuals of Calidris fuscicollis (Vieillot, 1819) were collected on the southern coast of Rio Grande do Sul, Brazil, with the objective of determining the presence of feather mites. Of the 80 birds examined, 32.5% were infested by mites, identified as Avenzoaria calidridis (Oudemans, 1904) (Avenzoariidae) (31.25%), Montchadskiana securicata (Megnin & Trouessart 1884) (Pterolichidae) (22.5%) and Alloptes limosae (Dubinin, 1951) (Alloptidae) (6.25...

  9. Sarcoptes scabiei mites modulate gene expression in human skin equivalents.

    Directory of Open Access Journals (Sweden)

    Marjorie S Morgan

    Full Text Available The ectoparasitic mite, Sarcoptes scabiei that burrows in the epidermis of mammalian skin has a long co-evolution with its hosts. Phenotypic studies show that the mites have the ability to modulate cytokine secretion and expression of cell adhesion molecules in cells of the skin and other cells of the innate and adaptive immune systems that may assist the mites to survive in the skin. The purpose of this study was to identify genes in keratinocytes and fibroblasts in human skin equivalents (HSEs that changed expression in response to the burrowing of live scabies mites. Overall, of the more than 25,800 genes measured, 189 genes were up-regulated >2-fold in response to scabies mite burrowing while 152 genes were down-regulated to the same degree. HSEs differentially expressed large numbers of genes that were related to host protective responses including those involved in immune response, defense response, cytokine activity, taxis, response to other organisms, and cell adhesion. Genes for the expression of interleukin-1α (IL-1α precursor, IL-1β, granulocyte/macrophage-colony stimulating factor (GM-CSF precursor, and G-CSF precursor were up-regulated 2.8- to 7.4-fold, paralleling cytokine secretion profiles. A large number of genes involved in epithelium development and keratinization were also differentially expressed in response to live scabies mites. Thus, these skin cells are directly responding as expected in an inflammatory response to products of the mites and the disruption of the skin's protective barrier caused by burrowing. This suggests that in vivo the interplay among these skin cells and other cell types, including Langerhans cells, dendritic cells, lymphocytes and endothelial cells, is responsible for depressing the host's protective response allowing these mites to survive in the skin.

  10. Sarcoptes scabiei Mites Modulate Gene Expression in Human Skin Equivalents

    Science.gov (United States)

    Morgan, Marjorie S.; Arlian, Larry G.; Markey, Michael P.

    2013-01-01

    The ectoparasitic mite, Sarcoptes scabiei that burrows in the epidermis of mammalian skin has a long co-evolution with its hosts. Phenotypic studies show that the mites have the ability to modulate cytokine secretion and expression of cell adhesion molecules in cells of the skin and other cells of the innate and adaptive immune systems that may assist the mites to survive in the skin. The purpose of this study was to identify genes in keratinocytes and fibroblasts in human skin equivalents (HSEs) that changed expression in response to the burrowing of live scabies mites. Overall, of the more than 25,800 genes measured, 189 genes were up-regulated >2-fold in response to scabies mite burrowing while 152 genes were down-regulated to the same degree. HSEs differentially expressed large numbers of genes that were related to host protective responses including those involved in immune response, defense response, cytokine activity, taxis, response to other organisms, and cell adhesion. Genes for the expression of interleukin-1α (IL-1α) precursor, IL-1β, granulocyte/macrophage-colony stimulating factor (GM-CSF) precursor, and G-CSF precursor were up-regulated 2.8- to 7.4-fold, paralleling cytokine secretion profiles. A large number of genes involved in epithelium development and keratinization were also differentially expressed in response to live scabies mites. Thus, these skin cells are directly responding as expected in an inflammatory response to products of the mites and the disruption of the skin’s protective barrier caused by burrowing. This suggests that in vivo the interplay among these skin cells and other cell types, including Langerhans cells, dendritic cells, lymphocytes and endothelial cells, is responsible for depressing the host’s protective response allowing these mites to survive in the skin. PMID:23940705

  11. Intra- and trans-generational costs of reduced female body size caused by food limitation early in life in mites.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2013-01-01

    Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs. Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons. Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism - females are the larger sex and thus more strongly affected by maternal stress than the smaller males - and to sexually selected lower plasticity of male body size.

  12. Intra- and Trans-Generational Costs of Reduced Female Body Size Caused by Food Limitation Early in Life in Mites

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2013-01-01

    Background Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs. Methodology/Principal Findings Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons. Conclusions/Significance Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism – females are the larger sex and thus more strongly affected by maternal stress than the smaller males – and to sexually selected lower plasticity of male body size. PMID:24265745

  13. Intra- and trans-generational costs of reduced female body size caused by food limitation early in life in mites.

    Directory of Open Access Journals (Sweden)

    Andreas Walzer

    Full Text Available Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs.Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons.Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism - females are the larger sex and thus more strongly affected by maternal stress than the smaller males - and to sexually selected lower plasticity of male body size.

  14. Threat-sensitive anti-intraguild predation behaviour: maternal strategies to reduce offspring predation risk in mites.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2011-01-01

    Predation is a major selective force for the evolution of behavioural characteristics of prey. Predation among consumers competing for food is termed intraguild predation (IGP). From the perspective of individual prey, IGP differs from classical predation in the likelihood of occurrence because IG prey is usually more rarely encountered and less profitable because it is more difficult to handle than classical prey. It is not known whether IGP is a sufficiently strong force to evolve interspecific threat sensitivity in antipredation behaviours, as is known from classical predation, and if so whether such behaviours are innate or learned. We examined interspecific threat sensitivity in antipredation in a guild of predatory mite species differing in adaptation to the shared spider mite prey (i.e. Phytoseiulus persimilis, Neoseiulus californicus and Amblyseius andersoni). We first ranked the players in this guild according to the IGP risk posed to each other: A. andersoni was the strongest IG predator; P. persimilis was the weakest. Then, we assessed the influence of relative IGP risk and experience on maternal strategies to reduce offspring IGP risk: A. andersoni was insensitive to IGP risk. Threat sensitivity in oviposition site selection was induced by experience in P. persimilis but occurred independently of experience in N. californicus. Irrespective of experience, P. persimilis laid fewer eggs in choice situations with the high- rather than low-risk IG predator. Our study suggests that, similar to classical predation, IGP may select for sophisticated innate and learned interspecific threat-sensitive antipredation responses. We argue that such responses may promote the coexistence of IG predators and prey.

  15. Phenotypic plasticity in anti-intraguild predator strategies: mite larvae adjust their behaviours according to vulnerability and predation risk.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2013-05-01

    Interspecific threat-sensitivity allows prey to maximize the net benefit of antipredator strategies by adjusting the type and intensity of their response to the level of predation risk. This is well documented for classical prey-predator interactions but less so for intraguild predation (IGP). We examined threat-sensitivity in antipredator behaviour of larvae in a predatory mite guild sharing spider mites as prey. The guild consisted of the highly vulnerable intraguild (IG) prey and weak IG predator Phytoseiulus persimilis, the moderately vulnerable IG prey and moderate IG predator Neoseiulus californicus and the little vulnerable IG prey and strong IG predator Amblyseius andersoni. We videotaped the behaviour of the IG prey larvae of the three species in presence of either a low- or a high-risk IG predator female or predator absence and analysed time, distance, path shape and interaction parameters of predators and prey. The least vulnerable IG prey A. andersoni was insensitive to differing IGP risks but the moderately vulnerable IG prey N. californicus and the highly vulnerable IG prey P. persimilis responded in a threat-sensitive manner. Predator presence triggered threat-sensitive behavioural changes in one out of ten measured traits in N. californicus larvae but in four traits in P. persimilis larvae. Low-risk IG predator presence induced a typical escape response in P. persimilis larvae, whereas they reduced their activity in the high-risk IG predator presence. We argue that interspecific threat-sensitivity may promote co-existence of IG predators and IG prey and should be common in predator guilds with long co-evolutionary history.

  16. Age and reproductive status of adult Varroa mites affect grooming success of honey bees.

    Science.gov (United States)

    Kirrane, Maria J; de Guzman, Lilia I; Rinderer, Thomas E; Frake, Amanda M; Wagnitz, Jeremy; Whelan, Pádraig M

    2012-12-01

    This study evaluated for the first time the grooming response of honey bees to Varroa mites of different ages and reproductive statuses in the laboratory. Plastic cages containing a section of dark comb and about 200 bees were inoculated with groups of four classes of mites: gravid, phoretic foundresses, phoretic daughters and a combination of gravid and phoretic foundress mites. Each cage received 20 mites belonging to one of these classes. Our results showed that, 1 day after mite inoculation, phoretic daughter mites were the most prone to grooming by honey bees with an average mite drop of 49.8 ± 2.6 %. The lowest mite drop was recorded for bees inoculated with phoretic foundresses (30.3 ± 3.6 %) but was comparable to bees inoculated with gravid mites (31.8 ± 3.8 %) and the combination of gravid and phoretic foundress mites (34.2 ± 3.2 %). No differences among mite types were detected during the second and third days of observation. Regardless of mite type, the highest mite drop was recorded on the first day (35 ± 2.1 %) compared to the drop for any subsequent day (grooming behaviour may increase our insight into the importance of grooming in mite resistance.

  17. SPIDER: Probing the Early Universe with a Suborbital Polarimeter

    Science.gov (United States)

    Fraisse, Aurélien A.; SPIDER Collaboration

    2012-01-01

    SPIDER is a balloon-borne polarimeter designed to detect a divergence-free polarization pattern ("B-modes") in the Cosmic Microwave Background (CMB). In the inflationary scenario, the spectrum of the tensor perturbations that generate this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. The expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological B-mode signal with r=0.03. An optimized scanning strategy enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while providing access to a relatively wide range of angular scales. In the SPIDER field, the polarized emission from interstellar dust is as bright or brighter than the cosmological r=0.03 B-mode signal at all SPIDER frequencies (90, 150, and 280 GHz), a situation similar to that found in the "Southern Hole." Despite this foreground contamination, two 20-day flights of the SPIDER instrument will constrain the amplitude of the B-mode signal to rAPRA-NNX07AL64G), the National Science Foundation (ANT-1043515), the Gordon and Betty Moore Foundation, and the David and Lucile Packard Foundation. Support in Canada is provided by NSERC, the Canadian Space Agency, the Canada Foundation for Innovation, and CIFAR.

  18. Spider Silk as Guiding Biomaterial for Human Model Neurons

    Directory of Open Access Journals (Sweden)

    Frank Roloff

    2014-01-01

    Full Text Available Over the last years, a number of therapeutic strategies have emerged to promote axonal regeneration. An attractive strategy is the implantation of biodegradable and nonimmunogenic artificial scaffolds into injured peripheral nerves. In previous studies, transplantation of decellularized veins filled with spider silk for bridging critical size nerve defects resulted in axonal regeneration and remyelination by invading endogenous Schwann cells. Detailed interaction of elongating neurons and the spider silk as guidance material is unknown. To visualize direct cellular interactions between spider silk and neurons in vitro, we developed an in vitro crossed silk fiber array. Here, we describe in detail for the first time that human (NT2 model neurons attach to silk scaffolds. Extending neurites can bridge gaps between single silk fibers and elongate afterwards on the neighboring fiber. Culturing human neurons on the silk arrays led to an increasing migration and adhesion of neuronal cell bodies to the spider silk fibers. Within three to four weeks, clustered somata and extending neurites formed ganglion-like cell structures. Microscopic imaging of human neurons on the crossed fiber arrays in vitro will allow for a more efficient development of methods to maximize cell adhesion and neurite growth on spider silk prior to transplantation studies.

  19. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    Energy Technology Data Exchange (ETDEWEB)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

    2010-08-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  20. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    International Nuclear Information System (INIS)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A; Hedhammar, My; Johansson, Jan; Blom, Tobias; Leifer, Klaus

    2010-01-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  1. Arachnid aloft: directed aerial descent in neotropical canopy spiders.

    Science.gov (United States)

    Yanoviak, Stephen P; Munk, Yonatan; Dudley, Robert

    2015-09-06

    The behaviour of directed aerial descent has been described for numerous taxa of wingless hexapods as they fall from the tropical rainforest canopy, but is not known in other terrestrial arthropods. Here, we describe similar controlled aerial behaviours for large arboreal spiders in the genus Selenops (Selenopidae). We dropped 59 such spiders from either canopy platforms or tree crowns in Panama and Peru; the majority (93%) directed their aerial trajectories towards and then landed upon nearby tree trunks. Following initial dorsoventral righting when necessary, falling spiders oriented themselves and then translated head-first towards targets; directional changes were correlated with bilaterally asymmetric motions of the anterolaterally extended forelegs. Aerial performance (i.e. the glide index) decreased with increasing body mass and wing loading, but not with projected surface area of the spider. Along with the occurrence of directed aerial descent in ants, jumping bristletails, and other wingless hexapods, this discovery of targeted gliding in selenopid spiders further indicates strong selective pressures against uncontrolled falls into the understory for arboreal taxa. © 2015 The Author(s).

  2. Detection and phylogenetic analysis of bacteriophage WO in spiders (Araneae).

    Science.gov (United States)

    Yan, Qian; Qiao, Huping; Gao, Jin; Yun, Yueli; Liu, Fengxiang; Peng, Yu

    2015-11-01

    Phage WO is a bacteriophage found in Wolbachia. Herein, we represent the first phylogenetic study of WOs that infect spiders (Araneae). Seven species of spiders (Araneus alternidens, Nephila clavata, Hylyphantes graminicola, Prosoponoides sinensis, Pholcus crypticolens, Coleosoma octomaculatum, and Nurscia albofasciata) from six families were infected by Wolbachia and WO, followed by comprehensive sequence analysis. Interestingly, WO could be only detected Wolbachia-infected spiders. The relative infection rates of those seven species of spiders were 75, 100, 88.9, 100, 62.5, 72.7, and 100 %, respectively. Our results indicated that both Wolbachia and WO were found in three different body parts of N. clavata, and WO could be passed to the next generation of H. graminicola by vertical transmission. There were three different sequences for WO infected in A. alternidens and two different WO sequences from C. octomaculatum. Only one sequence of WO was found for the other five species of spiders. The discovered sequence of WO ranged from 239 to 311 bp. Phylogenetic tree was generated using maximum likelihood (ML) based on the orf7 gene sequences. According to the phylogenetic tree, WOs in N. clavata and H. graminicola were clustered in the same group. WOs from A. alternidens (WAlt1) and C. octomaculatum (WOct2) were closely related to another clade, whereas WO in P. sinensis was classified as a sole cluster.

  3. Endemic harvestmen and spiders of Austria (Arachnida: Opiliones, Araneae

    Directory of Open Access Journals (Sweden)

    Komposch, Christian

    2011-01-01

    Full Text Available A comprehensive overview of plant, fungus and animal species of Austria revealed a total of 748 endemic and subendemic species, including, 11 harvestman and 46 spider species. Altogether two endemic harvestmen (Nemastoma bidentatum relictum, Nemastoma schuelleri and 8 endemic spiders (Abacoproeces molestus, Collinsia (caliginosa nemenziana, Mughiphantes severus, Mughiphantes styriacus, Pelecopsis alpica, Scotophaeus nanus, Troglohyphantes novicordis, Troglohyphantes tauriscus, beside 9 subendemic harvestman and 38 subendemic spider species have been recorded from Austria. Hot-spots of endemism in the Eastern Alps are the north-eastern (Ennstaler Alps and southern Calcareous Alps (Karawanken, Karnische Alps and the Central Alps (Hohe Tauern, Gurktaler Alps, Ötztaler and Stubaier Alps. Most of the endemic arachnid species occur from the nival down to the montane zone. Important habitats are rocky areas, caves and woodlands. High absolute numbers and percentages of endemics can be found within the harvestman families Cladonychiidae, Ischyropsalididae and Nemastomatidae and in the spider genera Lepthyphantes s. l. and Troglohyphantes. The conservation status of these highly endangered taxa – 85 % of the spider species and 100 % of the harvestman taxa are endangered in Austria – is poor.

  4. Radiation Safety System for SPIDER Neutral Beam Accelerator

    International Nuclear Information System (INIS)

    Sandri, S.; Poggi, C.; Coniglio, A.; D'Arienzo, M.

    2011-01-01

    SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

  5. Effects of attention manipulations on motivated attention to feared and nonfeared negative distracters in spider fear.

    Science.gov (United States)

    Norberg, Joakim; Wiens, Stefan

    2013-11-09

    When people view emotional and neutral pictures, the emotional pictures capture more attention than do neutral pictures. In support, studies with event-related potentials have shown that the early posterior negativity (EPN) and the late positive potential (LPP) to emotional versus neutral pictures are enhanced when pictures are attended. However, this motivated attention decreases when voluntary attention is directed away from the pictures. Most previous studies included only generally emotional pictures of either negative or positive valence. Because people with spider fear report intense fear of spiders, we examined whether directing attention away from emotional pictures at fixation decreases motivated attention less strongly for spiders than for generally negative distracters. We recorded event-related potentials from 128 channels to study whether manipulations of attention (i.e., spatial attention and perceptual load) decrease the EPN and the LPP to emotional distracters less strongly for spiders than for fear-irrelevant negative pictures in people with spider fear. Results confirmed that the EPN and the LPP to spiders (vs. neutral pictures) were particularly enhanced in participants with spider fear compared to participants without spider fear. When attention was directed away from the pictures, the EPN and the LPP to spiders (vs. neutral pictures) decreased similarly in fearful and nonfearful participants. Further, in fearful participants, the decrease in the EPN and the LPP was similar for spiders and for fear-irrelevant negative pictures. Our findings suggest that for people with spider fear, directing attention away from emotional pictures at fixation decreases motivated attention to these distracters similarly for spiders as for fear-irrelevant negative pictures. These findings imply that attention to spiders in spider fear does not exceed the level of attention expected from the spider pictures' high arousal and negative valence (i.e., their intrinsic

  6. Testing for reproductive interference in the population dynamics of two congeneric species of herbivorous mites

    Science.gov (United States)

    Sato, Y; Alba, J M; Sabelis, M W

    2014-01-01

    When phylogenetically close, two competing species may reproductively interfere, and thereby affect their population dynamics. We tested for reproductive interference (RI) between two congeneric haplo-diploid spider mites, Tetranychus evansi and Tetranychus urticae, by investigating their interspecific mating and their population dynamics when they competed on the same plants. They are both pests of tomato, but differ in the host plant defences that they suppress or induce. To reduce the effect of plant-mediated interaction, we used a mutant tomato plant lacking jasmonate-mediated anti-herbivore defences in the competition experiment. In addition, to manipulate the effect of RI, we introduced founder females already mated with conspecific males in mild RI treatments or founder, virgin females in strong RI treatments (in either case together with heterospecific and conspecific males). As females show first-male sperm precedence, RI should occur especially in the founder generation under strong RI treatments. We found that T. urticae outcompeted T. evansi in mild, but not in strong RI treatments. Thus, T. evansi interfered reproductively with T. urticae. This result was supported by crossing experiments showing frequent interspecific copulations, strong postmating reproductive isolation and a preference of T. evansi males to mate with T. urticae (instead of conspecific) females, whereas T. urticae males preferred conspecific females. We conclude that interspecific mating comes at a cost due to asymmetric mate preferences of males. Because RI by T. evansi can improve its competitiveness to T. urticae, we propose that RI partly explains why T. evansi became invasive in Europe where T. urticae is endemic. PMID:24865602

  7. Total effects of contact and residual exposure of bifenthrin and λ-cyhalothrin on the predatory mite Galendromus occidentalis (Acari: Phytoseiidae).

    Science.gov (United States)

    Hamby, Kelly A; Alifano, Jesse A; Zalom, Frank G

    2013-10-01

    Pyrethroid insecticides are generally regarded as acutely toxic to predatory phytoseiid mites; however, persistence of hull split spray pyrethroid residues on almond trees and their effects on phytoseiids have not been quantified over time. Hull split, the separation of the almond hull along the suture, exposes the new crop nuts to infestation by Amyelois transitella (Walker) larvae, and is the preferred timing for insecticides applied for their control. Galendromus occidentalis (Nesbitt) is the most important phytoseiid biocontrol agent for web-spinning spider mites in California (USA) almond orchards, and the impact of bifenthrin and λ-cyhalothrin pyrethroid residue on their survival, fertility, and fecundity was determined. The total effects of direct contact with esfenvalerate, permethrin, bifenthrin and λ-cyhalothrin were also evaluated for comparison. The total effects (E) of direct contact treatments of the four pyrethroids ranged from 77.8 % for esfenvalerate to 98.8 % for bifenthrin. Both bifenthrin and λ-cyhalothrin twig residue would be considered harmful (IOBC class 4) following field application at hull split timing. Bifenthrin twig residue would be considered slightly harmful (IOBC class 2) for up to 3.5 months and harmless (IOBC class 1) after 6 months. λ-cyhalothrin residue would be considered moderately harmful (IOBC class 3) for up to 3.5 months following application and harmless (IOBC class 1) after 6 months. Bifenthrin and λ-cyhalothrin twig residue on treated trees significantly reduced G. occidentalis female survival for up to 6 months post-treatment, however total effects (E) classify these residues as harmless (IOBC class 1) after 6 months. Harmful effects of direct and residual exposure following application have implications for the use of these pyrethroids in an integrated mite management program for perennial crops.

  8. Subsocial behaviour and brood adoption in mixed-species colonies of two theridiid spiders

    DEFF Research Database (Denmark)

    Grinsted, Lena; Agnarsson, Ingi; Bilde, Trine

    2012-01-01

    Cooperation and group living often evolves through kin selection. However, associations between unrelated organisms, such as different species, can evolve if both parties benefit from the interaction. Group living is rare in spiders, but occurs in cooperative, permanently social spiders, as well...... as in territorial, colonial spiders. Mixed species spider colonies, involving closely related species, have rarely been documented. We examined social interactions in newly discovered mixed-species colonies of theridiid spiders on Bali, Indonesia. Our aim was to test the degree of intra- and interspecific tolerance...

  9. Influence of spider silk on refugia preferences of the recluse spiders Loxosceles reclusa and Loxosceles laeta (Araneae: Sicariidae).

    Science.gov (United States)

    Vetter, Richard S; Rust, Michael K

    2010-06-01

    In a previous experimental study, recluse spiders Loxosceles reclusa Gertsch and Mulaik and Loxosceles laeta (Nicolet) (Araneae: Sicariidae) preferred small cardboard refugia covered with conspecific silk compared with never-occupied refugia. Herein, we investigated some factors that might be responsible for this preference using similar cardboard refugia. When the two Loxosceles species were given choices between refugia previously occupied by their own and by the congeneric species, neither showed a species-specific preference; however, each chose refugia coated with conspecific silk rather than those previously inhabited by a distantly related cribellate spider, Metaltella simoni (Keyserling). When L. laeta spiders were offered refugia that were freshly removed from silk donors compared with heated, aged refugia from the same silk donor, older refugia were preferred. Solvent extracts of L. laeta silk were chosen approximately as often as control refugia when a range of solvents (methylene chloride:methanol, water, and hexane) were used. However, when acetone was used on similar silk, there was a statistical preference for the control, indicating that there might be a mildly repellent aspect to acetone-washed silk. Considering the inability to show attraction to chemical aspects of fresh silk, it seems that physical attributes may be more important for selection and that there might be repellency to silk of a recently vacated spider. These findings are discussed in regard to pest management strategies to control recluse spiders.

  10. Prey interception drives web invasion and spider size determines successful web takeover in nocturnal orb-web spiders.

    Science.gov (United States)

    Gan, Wenjin; Liu, Shengjie; Yang, Xiaodong; Li, Daiqin; Lei, Chaoliang

    2015-09-24

    A striking feature of web-building spiders is the use of silk to make webs, mainly for prey capture. However, building a web is energetically expensive and increases the risk of predation. To reduce such costs and still have access to abundant prey, some web-building spiders have evolved web invasion behaviour. In general, no consistent patterns of web invasion have emerged and the factors determining web invasion remain largely unexplored. Here we report web invasion among conspecifics in seven nocturnal species of orb-web spiders, and examined the factors determining the probability of webs that could be invaded and taken over by conspecifics. About 36% of webs were invaded by conspecifics, and 25% of invaded webs were taken over by the invaders. A web that was built higher and intercepted more prey was more likely to be invaded. Once a web was invaded, the smaller the size of the resident spider, the more likely its web would be taken over by the invader. This study suggests that web invasion, as a possible way of reducing costs, may be widespread in nocturnal orb-web spiders. © 2015. Published by The Company of Biologists Ltd.

  11. Prey interception drives web invasion and spider size determines successful web takeover in nocturnal orb-web spiders

    Directory of Open Access Journals (Sweden)

    Wenjin Gan

    2015-10-01

    Full Text Available A striking feature of web-building spiders is the use of silk to make webs, mainly for prey capture. However, building a web is energetically expensive and increases the risk of predation. To reduce such costs and still have access to abundant prey, some web-building spiders have evolved web invasion behaviour. In general, no consistent patterns of web invasion have emerged and the factors determining web invasion remain largely unexplored. Here we report web invasion among conspecifics in seven nocturnal species of orb-web spiders, and examined the factors determining the probability of webs that could be invaded and taken over by conspecifics. About 36% of webs were invaded by conspecifics, and 25% of invaded webs were taken over by the invaders. A web that was built higher and intercepted more prey was more likely to be invaded. Once a web was invaded, the smaller the size of the resident spider, the more likely its web would be taken over by the invader. This study suggests that web invasion, as a possible way of reducing costs, may be widespread in nocturnal orb-web spiders.

  12. Multivariable control of a rolling spider drone

    Science.gov (United States)

    Lyu, Haifeng

    The research and application of Unmanned Aerial Vehicles (UAVs) has been a hot topic recently. A UAV is dened as an aircraft which is designed not to carry a human pilot or operated with remote electronic input by the flight controller. In this thesis, the design of a control system for a quadcopter named Rolling Spider Drone is conducted. The thesis work presents the design of two kinds of controllers that can control the Drone to keep it balanced and track different kinds of input trajectories. The nonlinear mathematical model for the Drone is derived by the Newton-Euler method. The rotational subsystem and translational system are derived to describe the attitude and position motion of Drone. Techniques from linear control theory are employed to linearize the highly coupled and nonlinear quadcopter plant around equilibrium points and apply the linear feedback controller to stabilize the system. The controller is a digital tracking system that deploys LQR for system stability design. Fixed gain and adaptive gain scheduled controllers are developed and compared with different LQR weights. Step references and reference trajectories involving signicant variation for the yaw angle in the xy-plane and three-dimensional spaces are tracked in the simulation. The physical implementation and an output feedback controller are considered for future work.

  13. Efficient Journaling for the Spider Storage System

    Energy Technology Data Exchange (ETDEWEB)

    Oral, H Sarp [ORNL; Wang, Feiyi [ORNL; Shipman, Galen M [ORNL; Dillow, David A [ORNL; Miller, Ross G [ORNL; Drokin, Oleg [ORNL

    2003-01-01

    Journaling is a widely used technique to increase file system robustness against meta data and/or data corruptions. While the overhead of journaling can be negligible for small-scale file systems, we found that two aspects of local back-end file system journaling significantly lower the overall performance of a large-scale parallel file system such as Lustre: extra head seeks and serialization of incoming client requests. Journal transactions reside on a separate area of the disk that the file data, and each commit of the journal requires a head seek. Incoming client requests become serialized and take a latency hit by waiting for a commit to occur before the reply is sent. In this paper we present two different approaches to increase the local back-end file system journaling efficiency, thus increasing the overall aggregate parallel file system efficiency. First, we present a hardware-based solution where a solid-state device is used as an external journaling device to minimize the disk head seek. Second, we introduce a software-based optimization to allow asynchronously commit multiple journal transactions on the local back-end file system to minimize the penalty of serialization. Both our solutions are experimentally tested on Oak Ridge National Laboratory's large-scale Spider storage system and our tests show that both methods nearly double the overall parallel write performance.

  14. Oral mite anaphylaxis caused by mite-contaminated okonomiyaki/ pancake-mix in Japan: 8 case reports and a review of 28 reported cases.

    Science.gov (United States)

    Takahashi, Kentaro; Taniguchi, Masami; Fukutomi, Yuma; Sekiya, Kiyoshi; Watai, Kentaro; Mitsui, Chihiro; Tanimoto, Hidenori; Oshikata, Chiyako; Tsuburai, Takahiro; Tsurikisawa, Naomi; Minoguchi, Kenji; Nakajima, Hiroshi; Akiyama, Kazuo

    2014-03-01

    Anaphylaxis after the ingestion of foods contaminated with mites has recently been recognized. Case series and case reports thus far have shown that mite-contaminated wheat flour is the major cause of oral mite anaphylaxis. However, we have found 8 cases of oral mite anaphylaxis which were caused by mite-contaminated okonomiyaki-mix, a savory Japanese style pancake mix, in our hospital. In addition to our 8 cases, the databases of MEDLINE and ICHUSHI were systematically searched for patients with oral mite anaphylaxis in Japan. Thirty-six patients including our 8 cases with oral mite anaphylaxis were identified. Thirty-four out of 36 cases (94%) ingested okonomiyaki or takoyaki, prepared at home using okonomiyaki-mix or takoyaki-mix which was previously opened and stored for months at ambient temperature. Microscopic examination of culprit mixes of 16 cases including our 1 case revealed contamination of mites such as Dermatophagoides farina (Der f) (5 cases), Tyrophagus putrescentiae (Tyr p) (4 cases), and Dermatophagoides pteronyssinus (Der p) (3 cases). The specific IgE to each mite is generally upregulated in these patients. Especially, the titers of specific IgE to Der p and Der f were more than class 2 in all cases. Mite-contaminated flavored flour is the major cause of oral mite anaphylaxis in Japan.

  15. Recombinant Spider Silks—Biopolymers with Potential for Future Applications

    Directory of Open Access Journals (Sweden)

    Thomas Scheibel

    2011-03-01

    Full Text Available Nature has evolved a range of materials that compete with man-made materials in physical properties; one of these is spider silk. Silk is a fibrous material that exhibits extremely high strength and toughness with regard to its low density. In this review we discuss the molecular structure of spider silk and how this understanding has allowed the development of recombinant silk proteins that mimic the properties of natural spider silks. Additionally, we will explore the material morphologies and the applications of these proteins. Finally, we will look at attempts to combine the silk structure with chemical polymers and how the structure of silk has inspired the engineering of novel polymers.

  16. Synthetic Adhesive Attachment Discs based on Spider Pyriform Silk Architecture

    Science.gov (United States)

    Jain, Dharamdeep; Sahni, Vasav; Dhinojwala, Ali

    2014-03-01

    Among the variety of silks produced by spiders, pyriform silk is used in conjunction with the dragline silk to attach webs to different surfaces. Cob weaver spiders employ different architectural patterns to utilize the pyriform silk and form attachment joints with each pattern having a characteristic adhesive performance. The staple pin architecture is a one of the strongest attachment designs employed by spiders to attach their webs. Here we use a synthetic approach to create the a similar patterned architecture attachment discs on aluminum substrate using thermoplastic polyurethane. Measurable pull off forces are generated when the synthetic discs are peeled off a surface. This innovative adhesive strategy can be a source of design in various biomedical applications. Financial Support from National Science Foundation.

  17. Final design of thermal diagnostic system in SPIDER ion source

    Energy Technology Data Exchange (ETDEWEB)

    Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Dalla Palma, M.; Pasqualotto, R.; Pomaro, N. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2016-11-15

    The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H{sup −} production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements. This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.

  18. Small Molecules from Spiders Used as Chemical Probes

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Kristensen, Anders S.; Strømgaard, Kristian

    2011-01-01

    Spiders are important species in ecological systems and as major predators of insects they are endowed with a plethora of low‐molecular‐weight natural products having intriguing biological activities. The isolation and biological characterization of these entities are well established, however......, only very recently have these compounds been used as templates for the design, synthesis, and biological evaluation of synthetic analogues. In contrast, the investigation of compounds responsible for chemical communication between spiders is far less developed, but recently new light has been shed onto...... the area of pheromones and allomones from spiders. Herein, we recapitulate these recent results, put them into perspective with previous findings, and provide an outlook for future studies of these chemotypes....

  19. Spider Silk Processing for Spidroin Recovery from Crossopriza Lyoni Web

    Science.gov (United States)

    Mohtar, J. A.; Ooi, W. L.; Yusuf, F.

    2018-03-01

    Spider silk is a potential biomaterial that can be used in various applications for its outstanding physicomechanical properties attributed by the spidroin composition. Efforts for commercializing spider silks have been mainly focused on the characterization of spidroins from the Entelegyne spiders for exceptional fibre construction. Hence, studies on silk proteins from the Haplogyne species remain neglected. The aim of this study is to isolate spidroin from Crossopriza lyoni web. Silk processing involved the pretreatment of fibres for the shell layer removal from the surface. A screening study was conducted to analyze the effect of temperature, incubation time and agitation speed on spidroin extraction using Ajisawa’s reagent by OFAT analysis followed by statistical optimization of the extraction process via RSM for maximal protein recovery. All parameters exerted significant effect on spidroin recovery (pspider silk to meet the demand for a variety of silk-based products in the near future.

  20. Final design of thermal diagnostic system in SPIDER ion source

    International Nuclear Information System (INIS)

    Brombin, M.; Dalla Palma, M.; Pasqualotto, R.; Pomaro, N.

    2016-01-01

    The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H"− production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements. This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.

  1. Analysis for the brazing deformation of AFA3G spider

    International Nuclear Information System (INIS)

    Lin Feng

    2015-01-01

    Spider, the key component of the AFA3G cluster control assemblies (RCCA), is brazed with body, vanes and fingers. Vacuum brazing is crucial in the spider process and it is directly relevant to the final product quality. This paper analyze the deformation of the AFA3G spider in vacuum brazing procedure based on a large amount of data. The results indicate that the parallelism of the finger is most affected by the brazing and its deformation has obvious regularity. Deformation is mainly caused by the different contraction directions of components along with the interactions among them during cooling process. An optimized design of the brazing fixture based on the regularity and the value of the deformation greatly improves the parallelism of the fingers. Besides, the vacuum brazing procedure also affects the hole diameter of the finger, however, we could reduce the deformation by using columnar pin on the brazing fixture. (author)

  2. Spider fauna of semiarid eastern Colorado agroecosystems: diversity, abundance, and effects of crop intensification.

    Science.gov (United States)

    Kerzicnik, Lauren M; Peairs, Frank B; Cushing, Paula E; Draney, Michael L; Merrill, Scott C

    2013-02-01

    Spiders are critical predators in agroecosystems. Crop management practices can influence predator density and diversity, which, in turn, can influence pest management strategies. Crop intensification is a sustainable agricultural technique that can enhance crop production although optimizing soil moisture. To date, there is no information on how crop intensification affects natural enemy populations, particularly spiders. This study had two objectives: to characterize the abundance and diversity of spiders in eastern Colorado agroecosystems, and to test the hypothesis that spider diversity and density would be higher in wheat (Triticum aestivum L.) in crop-intensified rotations compared with wheat in conventional rotations. We collected spiders through pitfall, vacuum, and lookdown sampling from 2002 to 2007 to test these objectives. Over 11,000 spiders in 19 families from 119 species were captured from all sampling techniques. Interestingly, the hunting spider guild represented 89% of the spider fauna captured from all sites with the families Gnaphosidae and Lycosidae representing 75% of these spiders. Compared with European agroecosystems, these agroecosystems had greater diversity, which can be beneficial for the biological control of pests. Overall, spider densities were low in these semiarid cropping systems, and crop intensification effects on spider densities were not evident at this scale.

  3. Immunotherapy with the storage mite lepidoglyphus destructor.

    Science.gov (United States)

    Armentia-Medina, A; Tapias, J A; Martín, J F; Ventas, P; Fernández, A

    1995-01-01

    We carried out a double-blind clinical trial of immunotherapy on 35 patients sensitized to the storage mite Lepidoglyphus destructor (Ld). Before and after 12 months of specific hyposensitization (Abelló Lab., Spain) we performed in vivo (skin tests with Ld, methacholine and challenge tests), and in vitro tests (specific IgE, IgG, IgG1 and IgG4 to Ld and specific IgE, IgG, IgG1 and IgG4 to their major allergen Lep dI). We also monitored the efficacy and safety of the immunotherapy with clinical and analytical controls (symptoms and medication score, detection of immune complexes). After therapy we found a significant decrease in specific skin reactivity, dose of positive challenge tests, and hyperresponsiveness to methacholine. Sputum eosinophilia decreased. Specific IgE to Ld was increased and we also observed an increase in specific IgG1 and IgG4 to Ld and Lep DI. The placebo group showed no changes in these variables. There were no severe secondary reactions after treatment with the extract. Patients-self-evaluation was favourable and their labour absence decreased. No development of circulating immune complexes was associated with this immunotherapy.

  4. Foliar nectar enhances plant-mite mutualisms: the effect of leaf sugar on the control of powdery mildew by domatia-inhabiting mites.

    Science.gov (United States)

    Weber, Marjorie G; Porturas, Laura D; Taylor, Scott A

    2016-09-01

    Mite domatia are small structures on the underside of plant leaves that provide homes for predacious or fungivorous mites. In turn, mites inhabiting domatia defend the plant by consuming leaf herbivores and pathogens, which can result in a domatia-mediated, plant-mite defence mutualism. Several recent studies have suggested that plants receive enhanced benefits when they provide a foliar food source, such as sugars secreted from extrafloral nectaries, to mite mutualists alongside mite domatia. However, the effect of foliar sugar on reducing leaf pathogen load via domatia-inhabiting mites has not been directly investigated. To fill this gap, the links between foliar sugar addition, domatia-inhabiting mite abundance, and pathogen load were experimentally evaluated in wild grape. Furthermore, because the proposed combined benefits of providing food and housing have been hypothesized to select for the evolutionary correlation of extrafloral nectaries and domatia across plant lineages, a literature survey aimed at determining the overlap of mite domatia and extrafloral nectaries across plant groups was also conducted. It was found that leaves with artificial addition of foliar sugar had 58-80 % more mites than leaves without foliar sugar addition, and that higher mite abundances translated to reduced powdery mildew (Erysiphe necator) loads on leaves. It was found that mite domatia and extrafloral nectaries occur non-randomly in the same clades across Eudicots. Genera with both traits are reported to highlight candidate lineages for future studies. Together, the results demonstrate that foliar sugar can indeed enhance the efficacy of domatia-mediated plant-mite mutualisms, and suggest that this synergism has the potential to influence the co-distribution of foliar nectar and mite domatia across plants. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. An image filtering technique for SPIDER visible tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fonnesu, N., E-mail: nicola.fonnesu@igi.cnr.it; Agostini, M.; Brombin, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2014-02-15

    The tomographic diagnostic developed for the beam generated in the SPIDER facility (100 keV, 50 A prototype negative ion source of ITER neutral beam injector) will characterize the two-dimensional particle density distribution of the beam. The simulations described in the paper show that instrumental noise has a large influence on the maximum achievable resolution of the diagnostic. To reduce its impact on beam pattern reconstruction, a filtering technique has been adapted and implemented in the tomography code. This technique is applied to the simulated tomographic reconstruction of the SPIDER beam, and the main results are reported.

  6. An image filtering technique for SPIDER visible tomography

    International Nuclear Information System (INIS)

    Fonnesu, N.; Agostini, M.; Brombin, M.; Pasqualotto, R.; Serianni, G.

    2014-01-01

    The tomographic diagnostic developed for the beam generated in the SPIDER facility (100 keV, 50 A prototype negative ion source of ITER neutral beam injector) will characterize the two-dimensional particle density distribution of the beam. The simulations described in the paper show that instrumental noise has a large influence on the maximum achievable resolution of the diagnostic. To reduce its impact on beam pattern reconstruction, a filtering technique has been adapted and implemented in the tomography code. This technique is applied to the simulated tomographic reconstruction of the SPIDER beam, and the main results are reported

  7. Irradiation as a phytosanitary treatment for mites of the specie Tyrophagus putrescentiae (Acari: Acaridae)

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Valter, E-mail: varthur@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Radiobiologia e Ambiente; Mineiro, Jeferson L.C. [Instituto Biologico de Sao Paulo/APTA, Sao Paulo, SP (Brazil). Lab. de Entomologia Economico

    2009-07-01

    In great populations mites of the specie Tyrophagus putrescentiae can cause damages in stored products. The work had as objective to evaluate the effects of the gamma radiation of the Cobalt-60 to control the mites of the specie T. putrescentiae. The mites were irradiated with doses of 0 (control), 300, 400, 500, 600, 700, 800 Gy, in a source of Cobalt-60 type Gammacell-220, with a dose rate of 0.718 kGy/hour. Each treatment consisted of four repetitions containing 10 mites each, in a total of approximately 40 mites for treatment. The evaluations were daily, being counted the number of mites died, put eggs and emerged larvae. Based on the obtained results it was concluded that the dose sterilizing for the mites of this specie was of 300 Gy. Already the dose of 600 Gy induced the total mortality of the mites after 11 days of the irradiation process. (author)

  8. Optimization of spray deposition and Tetranychus urticae control with air assisted and electrostatic sprayer

    Directory of Open Access Journals (Sweden)

    Denise Tourino Rezende de Cerqueira

    Full Text Available ABSTRACT: Improved spray deposition can be attained by electrostatically charging spray droplets, which increases the attraction of droplets to plants and decreases operator exposure to pesticide and losses to the environment. However, this technique alone is not sufficient to achieve desirable penetration of the spray solution into the crop canopy; thus, air assistance can be added to the electrostatic spraying to further improve spray deposition. This study was conducted to compare different spraying technologies on spray deposition and two-spotted spider mite control in cut chrysanthemum. Treatments included in the study were: conventional TJ 8003 double flat fan nozzles, conventional TXVK-3 hollow cone nozzles, semi-stationary motorized jet launched spray with electrostatic spray system (ESS and air assistance (AA, and semi-stationary motorized jet launched spray with AA only (no ESS. To evaluate the effect of these spraying technologies on the control of two-spotted spider mite, a control treatment was included that did not receive an acaricide application. The AA spraying technology, with or without ESS, optimized spray deposition and provided satisfactory two-spotted spider mite control up to 4 days after application.

  9. Candidate predators for biological control of the poultry red mite Dermanyssus gallinae

    NARCIS (Netherlands)

    Lesna, I.; Wolfs, P.; Faraji, F.; Roy, L.; Komdeur, J.; Sabelis, M.W.

    2009-01-01

    The poultry red mite, Dermanyssus gallinae, is currently a significant pest in the poultry industry in Europe. Biological control by the introduction of predatory mites is one of the various options for controlling poultry red mites. Here, we present the first results of an attempt to identify

  10. Candidate predators for biological control of the poultry red mite Dermanyssus gallinae

    NARCIS (Netherlands)

    Lesna, Izabela; Wolfs, Peter; Faraji, Farid; Roy, Lise; Komdeur, Jan; Sabelis, Maurice W.

    The poultry red mite, Dermanyssus gallinae, is currently a significant pest in the poultry industry in Europe. Biological control by the introduction of predatory mites is one of the various options for controlling poultry red mites. Here, we present the first results of an attempt to identify

  11. Prevailing indoor climate classification to predict house-dust mite abundance in Dutch homes

    NARCIS (Netherlands)

    Schober, G.; Verstappen, I.; Snijders, M.C.L.; Bronswijk, van J.E.M.H.

    1995-01-01

    In Europe 10-15 % of the human population is sensitized to allergens of house dust mites (Pyroglyphidae). Population development of house dust mites is primarily influenced by water activity (aw) of the mite habitat. The availability of H20 (water-activity and relative humidity) in the niches of

  12. A survey of mites on farm animals in Libya.

    Science.gov (United States)

    Gabaj, M M; Beesley, W N; Awan, M A

    1992-10-01

    In 1985-1988, 2287 farm animals (cattle, camels, sheep, goats, horses, donkeys, dogs and rabbits) suspected of carrying parasitic mites were examined at 58 farms throughout Libya. Mites were identified on 1303 of these animals. The commonest parasites on cattle were Psoroptes and Chorioptes, on camels and sheep were Sarcoptes and Psoroptes, and on goats were Sarcoptes and Demodex. Infested horses carrier Psoroptes or Chorioptes, and one donkey carried Sarcoptes. Otodectes was common on dogs, but Sarcoptes was rare and no Demodex were seen. Rabbits often had psoroptic ear mange or sarcoptic body mange. Dermanyssus gallinae and Ornithonyssus bursa were seen on chickens, but no mites were found on pigeons, ducks or turkeys.

  13. Dermatitis due to Mixed Demodex and Sarcoptes Mites in Dogs

    Directory of Open Access Journals (Sweden)

    B. Sudhakara Reddy

    2014-01-01

    Full Text Available In dogs, dermatitis due to mixed mite infestation is rare. During the five-year period of study, two dogs were identified suffering from dermatitis due to mixed Demodex and Sarcoptes mites. Upon clinical examination dogs had primary and secondary skin lesions on face, around the ears, chin, neck, fore limbs and lateral abdomen. Microscopic examination of skin scrapings revealed Demodex and Sarcoptes mites. Both dogs were treated with daily oral ivermectin at 100 to 400 μg/kg body weight as incremental doses, external application of amitraz and supportive treatments with topical antimicrobial shampoo. After completion of forty-two days of therapy, dogs were recovered from the dermatitis.

  14. mites y control constitucional en México

    Directory of Open Access Journals (Sweden)

    Arminda Balbuena Cisneros

    2007-01-01

    Full Text Available Los límites a la reforma constitucional es un tema siempre vigente en el derecho constitucional, ello es así por las posibles arbitrariedades que pueden cometer los órganos detentadores del poder mediante las modificaciones a la constitución. En México, hoy en día este tema cobra particular relevancia por el profundo proceso de reforma que se vive, y por la controvertida posición que la corte mexicana ha adoptado en relación con los límites a la reforma. El presente artículo trata de dar una visión general de los límites al poder de reforma y, en particular, de la posición que la suprema corte de justicia de la nación ha adoptado respecto a los mismos.

  15. variability in condensed tannins and bitterness in spider plant ...

    African Journals Online (AJOL)

    ACSS

    Spider plant (Cleome gynandra L.) contributes considerably to the nutrition and medicines of communities in southern Africa. However, its utilisation is limited by its bitterness caused by condensed tannins. Unfortunately, processing options that reduce the bitterness also remove nutritionally and medicinally useful ...

  16. Crab spiders (Araeneae: Philodromidae, Thomisidae) of Ramsey County, Minnesota.

    Science.gov (United States)

    Daniel. T. Jennings; Bruce Cutler

    1996-01-01

    Crab spiders of 2 families, 10 genera, and 35 species were collected over a 31-year period in Ramsey County, Minnesota. Rarely collected species included Philodromus keyserlingi, Xysticus pellax, X. chippewa, X. banksi and X. alboniger. Identification source(s), season and collection frequency, and biology are summarized for each species.

  17. Inactivation of complement by Loxosceles reclusa spider venom.

    Science.gov (United States)

    Gebel, H M; Finke, J H; Elgert, K D; Cambell, B J; Barrett, J T

    1979-07-01

    Zymosan depletion of serum complement in guinea pigs rendered them highly resistant to lesion by Loxosceles reclusa spider venom. Guinea pigs deficient in C4 of the complement system are as sensitive to the venom as normal guinea pigs. The injection of 35 micrograms of whole recluse venom intradermally into guinea pigs lowered their complement level by 35.7%. Brown recluse spider venom in concentrations as slight as 0.02 micrograms protein/ml can totally inactivate one CH50 of guinea pig complement in vitro. Bee, scorpion, and other spider venoms had no influence on the hemolytic titer of complement. Fractionation of recluse spider venom by Sephadex G-200 filtration separated the complement-inactivating property of the venom into three major regions which could be distinguished on the basis of heat stability as well as size. None was neutralized by antivenom. Polyacrylamide gel electrophoresis of venom resolved the complement inactivators into five fractions. Complement inactivated by whole venom or the Sephadex fractions could be restored to hemolytic activity by supplements of fresh serum but not by heat-inactivated serum, pure C3, pure C5, or C3 and C5 in combination.

  18. Effects of Packaging and Storage Conditions on Quality of Spider ...

    African Journals Online (AJOL)

    African Journal of Food, Agriculture, Nutrition and Development ... However, quality of spider plant seed is affected by one or more factors that cause negative ... The purpose of this research was to increase insight into how the seed quality of ...

  19. Biotechnological Trends in Spider and Scorpion Antivenom Development

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Solà, Mireia; Jappe, Emma Christine

    2016-01-01

    Spiders and scorpions are notorious for their fearful dispositions and their ability to inject venom into prey and predators, causing symptoms such as necrosis, paralysis, and excruciating pain. Information on venom composition and the toxins present in these species is growing due to an interest...

  20. Spiders (Araneae) as polyphagous natural enemies in orchards

    NARCIS (Netherlands)

    Bogya, S.

    1999-01-01

    Spiders (Araneae) occur in high abundance in all terrestrial ecosystems including agro-ecosystems. They are a very heterogeneous group of animals with different hunting tactics and therefore they play very different ecological roles. At family level these tactics are rather similar thus

  1. Competition between introduced and native spiders (Araneae: Linyphiidae)

    Science.gov (United States)

    Houser, J.D.; Ginsberg, Howard S.; Jakob, Elizabeth M.

    2014-01-01

    The European sheet-web spider Linyphia triangularis (Araneae: Linyphiidae) has become established in Maine, where it often reaches very high densities. Two lines of evidence from previous work suggest that L. triangularis affects populations of the native linyphiid spider Frontinella communis. First, F. communis individuals are relatively scarce in both forest and coastal habitat where L. triangularis is common, but more common where L. triangularis is at low density. Second, in field experiments, F. communis species are less likely to settle in experimental plots when L. triangularis is present, and F. communis disappears from study plots when L. triangularis is introduced. Here we test two mechanisms that may underlie these patterns. First, we tested whether L. triangularis invades and usurps the webs of F. communis. When spiders were released onto webs of heterospecifics, L. triangularis was more likely to take over or share webs of F. communis than the reverse. We also observed natural takeovers of F. communis webs. Second, we explored the hypothesis that L. triangularis reduces prey availability for native species. We sampled flying prey in areas with L. triangularis and those where it had been removed, and found no effect of spider presence on measured prey density. We also found no effect of prey supplementation on web tenacity in F. communis, suggesting that F. communis movements are not highly dependent on prey availability. We conclude that web takeover is likely more important than prey reduction in driving negative effects of L. triangularis on F. communis.

  2. Determination of PCDDs in spider webs: preliminary studies

    Science.gov (United States)

    Rybak, Justyna; Rutkowski, Radosław

    2018-01-01

    The application of spider webs for determination of polichlorinated dibenzo-para-dioxins (PCDDs) has been studied for the first time. The aim of the studies was to find out if spider webs are suitable for such examinations as it was proved in the previous research they are excellent indicators of air pollutants. Spiders are ubiquitous, thus collection of samples is easy and non-invasive. Studies were conducted within the city of Wrocław and surroundings, one of the biggest and at the same time heaviest polluted city in Poland. Five research sites have been chosen, where spider webs were collected after 60 days of continuous exposure time. Webs belonging to two genera Tegenaria sylvestris and Tegenaria ferruginea (family Agelenidae) have been chosen as they are large and very dense, thus they are very suitable for such examinations. Webs were found to retain dioxins probably mainly by external exposure. These promising results should be continued and expanded in the future research.

  3. The ITER Neutral Beam Test Facility towards SPIDER operation

    Science.gov (United States)

    Toigo, V.; Dal Bello, S.; Gaio, E.; Luchetta, A.; Pasqualotto, R.; Zaccaria, P.; Bigi, M.; Chitarin, G.; Marcuzzi, D.; Pomaro, N.; Serianni, G.; Agostinetti, P.; Agostini, M.; Antoni, V.; Aprile, D.; Baltador, C.; Barbisan, M.; Battistella, M.; Boldrin, M.; Brombin, M.; Dalla Palma, M.; De Lorenzi, A.; Delogu, R.; De Muri, M.; Fellin, F.; Ferro, A.; Gambetta, G.; Grando, L.; Jain, P.; Maistrello, A.; Manduchi, G.; Marconato, N.; Pavei, M.; Peruzzo, S.; Pilan, N.; Pimazzoni, A.; Piovan, R.; Recchia, M.; Rizzolo, A.; Sartori, E.; Siragusa, M.; Spada, E.; Spagnolo, S.; Spolaore, M.; Taliercio, C.; Valente, M.; Veltri, P.; Zamengo, A.; Zaniol, B.; Zanotto, L.; Zaupa, M.; Boilson, D.; Graceffa, J.; Svensson, L.; Schunke, B.; Decamps, H.; Urbani, M.; Kushwah, M.; Chareyre, J.; Singh, M.; Bonicelli, T.; Agarici, G.; Garbuglia, A.; Masiello, A.; Paolucci, F.; Simon, M.; Bailly-Maitre, L.; Bragulat, E.; Gomez, G.; Gutierrez, D.; Mico, G.; Moreno, J.-F.; Pilard, V.; Chakraborty, A.; Baruah, U.; Rotti, C.; Patel, H.; Nagaraju, M. V.; Singh, N. P.; Patel, A.; Dhola, H.; Raval, B.; Fantz, U.; Fröschle, M.; Heinemann, B.; Kraus, W.; Nocentini, R.; Riedl, R.; Schiesko, L.; Wimmer, C.; Wünderlich, D.; Cavenago, M.; Croci, G.; Gorini, G.; Rebai, M.; Muraro, A.; Tardocchi, M.; Hemsworth, R.

    2017-08-01

    SPIDER is one of two projects of the ITER Neutral Beam Test Facility under construction in Padova, Italy, at the Consorzio RFX premises. It will have a 100 keV beam source with a full-size prototype of the radiofrequency ion source for the ITER neutral beam injector (NBI) and also, similar to the ITER diagnostic neutral beam, it is designed to operate with a pulse length of up to 3600 s, featuring an ITER-like magnetic filter field configuration (for high extraction of negative ions) and caesium oven (for high production of negative ions) layout as well as a wide set of diagnostics. These features will allow a reproduction of the ion source operation in ITER, which cannot be done in any other existing test facility. SPIDER realization is well advanced and the first operation is expected at the beginning of 2018, with the mission of achieving the ITER heating and diagnostic NBI ion source requirements and of improving its performance in terms of reliability and availability. This paper mainly focuses on the preparation of the first SPIDER operations—integration and testing of SPIDER components, completion and implementation of diagnostics and control and formulation of operation and research plan, based on a staged strategy.

  4. Remote monitoring of vibrational information in spider webs

    Science.gov (United States)

    Mortimer, B.; Soler, A.; Siviour, C. R.; Vollrath, F.

    2018-06-01

    Spiders are fascinating model species to study information-acquisition strategies, with the web acting as an extension of the animal's body. Here, we compare the strategies of two orb-weaving spiders that acquire information through vibrations transmitted and filtered in the web. Whereas Araneus diadematus monitors web vibration directly on the web, Zygiella x-notata uses a signal thread to remotely monitor web vibration from a retreat, which gives added protection. We assess the implications of these two information-acquisition strategies on the quality of vibration information transfer, using laser Doppler vibrometry to measure vibrations of real webs and finite element analysis in computer models of webs. We observed that the signal thread imposed no biologically relevant time penalty for vibration propagation. However, loss of energy (attenuation) was a cost associated with remote monitoring via a signal thread. The findings have implications for the biological use of vibrations by spiders, including the mechanisms to locate and discriminate between vibration sources. We show that orb-weaver spiders are fascinating examples of organisms that modify their physical environment to shape their information-acquisition strategy.

  5. Multiple origins of subsociality in crab spiders (Thomisidae).

    Science.gov (United States)

    Ruch, Jasmin; Riehl, Torben; May-Collado, Laura J; Agnarsson, Ingi

    2015-01-01

    Determining factors that facilitate the transition from a solitary to a social lifestyle is a major challenge in evolutionary biology, especially in taxa that are usually aggressive towards conspecifics. Most spiders live solitarily and few species are known to be social. Nevertheless, sociality has evolved multiple times across several families and nearly all studied social lineages have originated from a periodically social (subsocial) ancestor. Group-living crab spiders (Thomisidae) are exclusively found in Australia and differ from most other social spiders because they lack a communal capture web. Three of the group-living species were placed in the genus Diaea and another in the genus Xysticus. Most Australian thomisids are, however, difficult to identify as most descriptions are old and of poor quality, and the genera Diaea and Xysticus may not correspond to monophyletic groups. Here, we clarify the phylogenetic relationships of the four group-living Australian thomisids and conclude that amongst these subsociality has evolved two to three times independently. The subsocial Xysticus bimaculatus is not closely related to any of the social Diaea and an independent origin of subsociality is likely in this case. The presented data indicates that within Diaea two origins of subsociality are possible. Our results help to understand the evolution of sociality in thomisids and support the hypothesis that permanent sociality in spiders has evolved multiple times relatively recently from subsocial ancestors. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Preservice Teachers' Conceptions about Animals and Particularly about Spiders

    Science.gov (United States)

    Jambrina, Carmen Urones; Vacas, Jose Manuel; Sanchez-Barbudo, Miguel

    2010-01-01

    Introduction: This article explores the scientific ideas and alternative conceptions that pre-service teachers have regarding animal classification and spiders in particular. Method: The study involved 40 pre-service teachers of elementary education in Spain and the data was collected by means of questionnaires, descriptions and drawings. The…

  7. Untangling the web...spiders in Arizona fields

    Science.gov (United States)

    Many kinds of arthropod natural enemies (predators and parasitoids) inhabit crop fields in Arizona and can have a large negative impact on several pest insect species that also infest these crops. Many different species of spiders are common in cotton, alfalfa and other crops in Arizona. Among the ...

  8. Taxonomic revision of the spider family Penestomidae (Araneae, Entelegynae)

    NARCIS (Netherlands)

    Miller, J.A.; Griswold, C.E.; Haddad, C.R.

    2010-01-01

    Conflicting character evidence and a scarcity of male specimens has historically made placement of the spider subfamily Penestominae Simon problematic. The Penestominae was recently removed from the family Eresidae and promoted to family rank based on the results of a molecular phylogenetic study; a

  9. SPIDER OPTIMIZATION. II. OPTICAL, MAGNETIC, AND FOREGROUND EFFECTS

    International Nuclear Information System (INIS)

    O'Dea, D. T.; Clark, C. N.; Contaldi, C. R.; Ade, P. A. R.; Amiri, M.; Burger, B.; Davis, G.; Benton, S. J.; Bock, J. J.; Crill, B. P.; Dore, O.; Filippini, J. P.; Bond, J. R.; Farhang, M.; Bonetti, J. A.; Bryan, S.; Chiang, H. C.; Fraisse, A. A.; Fissel, L. M.; Gandilo, N. N.

    2011-01-01

    SPIDER is a balloon-borne instrument designed to map the polarization of the cosmic microwave background (CMB) with degree-scale resolution over a large fraction of the sky. SPIDER's main goal is to measure the amplitude of primordial gravitational waves through their imprint on the polarization of the CMB if the tensor-to-scalar ratio, r, is greater than 0.03. To achieve this goal, instrumental systematic errors must be controlled with unprecedented accuracy. Here, we build on previous work to use simulations of SPIDER observations to examine the impact of several systematic effects that have been characterized through testing and modeling of various instrument components. In particular, we investigate the impact of the non-ideal spectral response of the half-wave plates, coupling between focal-plane components and Earth's magnetic field, and beam mismatches and asymmetries. We also present a model of diffuse polarized foreground emission based on a three-dimensional model of the Galactic magnetic field and dust, and study the interaction of this foreground emission with our observation strategy and instrumental effects. We find that the expected level of foreground and systematic contamination is sufficiently low for SPIDER to achieve its science goals.

  10. Czech Republic – the type material of spiders (Araneae)

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil; Kůrka, A.; Buchar, J.; Řezáč, M.

    2005-01-01

    Roč. 174, 1-4 (2005), s. 13-64 ISSN 0139-9543 R&D Projects: GA AV ČR(CZ) IAA6007401 Institutional research plan: CEZ:AV0Z50070508 Keywords : spider s * type material * Czech Republic Subject RIV: EG - Zoology

  11. On the Colours of Spider Orb-Webs

    Science.gov (United States)

    Suhr, Wilfried; Schlichting, H. Joachim

    2011-01-01

    A sticky capture thread from the spiral element of spider orb-webs is formed of almost regularly spaced droplets that surround a supporting axial fibre. From the perspective of physical optics it represents a periodic linear array of scattering elements that acts as a diffraction grating. This is a novel aspect, which is of vital importance for…

  12. Central European habitats inhabited by spiders with disjunctive distributions

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil

    2011-01-01

    Roč. 59, č. 2 (2011), s. 367-380 ISSN 1505-2249 Institutional research plan: CEZ:AV0Z50070508 Keywords : spider s * glacial relicts * boreomontane species Subject RIV: EH - Ecology, Behaviour Impact factor: 0.506, year: 2011

  13. Ballooning behavior in the golden orbweb spider Nephilapilipes (Araneae: Nephilidae

    Directory of Open Access Journals (Sweden)

    Vanessa M.J. Lee

    2015-01-01

    Full Text Available Ballooning, a mode of aerial dispersal in spiders, is an innate behavior that requires appropriate physiological and meteorological conditions. Although only rarely reported in the golden orbweb spiders, family Nephilidae, the large geographic distributions of most nephilids—in particular of Nephila species—would imply that these spiders likely routinely disperse by ballooning in spite of giant female sizes. Here we study ballooning behavior in the golden orbweb spider Nephila pilipes (Fabricius, 1793. Specifically, we test for the propensity of spiderlings to deploy ballooning as a dispersal mechanism. We subjected a total of 59 first-instar spiderlings to a wind experiment at two wind speeds (2.17 ± 0.02 m s-1 and 3.17 ± 0.02 m s-1 under laboratory conditions. Under an average wind speed of 3.17 m s-1, none of the spiderlings exhibited pre-ballooning or ballooning behavior. However, at an average wind speed of 2.17 m s-1, 53 (89.8% spiderlings showed pre-ballooning behavior, and 17 (32.1% of the pre-ballooners ultimately ballooned. Our results concur with prior reports on spiderlings of other families that pre-ballooning behavior is a requirement for ballooning to occur. Furthermore, although we cannot rule out other dispersal mechanisms such as synanthropic spread, our findings suggest that the widespread N. pilipes uses ballooning to colonize remote oceanic islands.

  14. Mating duration and sperm precedence in the spider Linyphia triangularis

    DEFF Research Database (Denmark)

    Weldingh, Ditte L.; Toft, Søren; Larsen, Ole Næsbye

    2011-01-01

    , especially the males, are able to influence the outcome of mating for their own benefit. We studied the linyphiid spider Linyphia triangularis in which mating follows a strict sequence during which the male inducts two droplets of sperm and transfers them to the female. We performed sperm competition...

  15. Spider diversity in coffee agroecosystems: the influence of agricultural intensification and aggressive ants.

    Science.gov (United States)

    Marín, Linda; Perfecto, Ivette

    2013-04-01

    Spiders are a very diverse group of invertebrate predators found in agroecosystems and natural systems. However, spider distribution, abundance, and eventually their ecological function in ecosystems can be influenced by abiotic and biotic factors such as agricultural intensification and dominant ants. Here we explore the influence of both agricultural intensification and the dominant arboreal ant Azteca instabilis on the spider community in coffee agroecosystems in southern Mexico. To measure the influence of the arboreal ant Azteca instabilis (F. Smith) on the spider community inhabiting the coffee layer of coffee agroecosystems, spiders were collected from coffee plants that were and were not patrolled by the ant in sites differing in agricultural intensification. For 2008, generalized linear mixed models showed that spider diversity was affected positively by agricultural intensification but not by the ant. However, results suggested that some spider species were associated with A. instabilis. Therefore, in 2009 we concentrated our research on the effect of A. instabilis on spider diversity and composition. For 2009, generalized linear mixed models show that spider richness and abundance per plant were significantly higher in the presence of A. instabilis. In addition, analyses of visual counts of insects and sticky traps data show that more resources were present in plants patrolled by the ant. The positive effect of A. instabilis on spiders seems to be caused by at least two mechanisms: high abundance of insects and protection against predators.

  16. Characteristics of the first recorded spider (Arthropoda: Arachnida fauna from Sheringal, Khyber Pakhtunkhwa, Pakistan

    Directory of Open Access Journals (Sweden)

    Farzana Khan Perveen

    2015-12-01

    Full Text Available The spiders (order: Aranae are an important environmental indicator and play a significant role as predators in biological control of the most of the key insect pests. The present study was conducted to establish the characteristics of the first recorded spider fauna from Sheringal, Dir Upper (DU, Khyber Pakhtunkhwa (KP, Pakistan during June 2013-July 2014. Their 10 species belong to 7 families, and 10 genera (nt=123: total; ni=77: identified; nui=46: unidentified were recorded in the 6 quadrates, i.e., Daramdala, Doki, Guryaal, Samang, Shahoor and Sia-Sheringal of Sheringal. The largest family was Lycosidae (wolf spiders with respect to size and numbers of specimens collected (n=20, which contained Arctosa littorali Simon, 1897; Hippasa partita Takidar, 1970; Pardosa distincta Backwall, 1867, while the smallest family was Gnphosidae (ground spiders (n=3 with Gnaphosa eucalyptus Ghafoor and Beg, 2002; while other families Sparassidae (huntsman spiders (n=19 Halconia insignis Thorell, 1836, and Isopeda tuhogniga Barrion and Litsinger, 1995, Opilionidae (harvestmen spiders (n=12 Hadrobunus grandis Sundevall, 1833; Pholcidae (cellar spider (n=10 have Crossopriza lyoni Blackwall, 1867; Hersiliidae (two-tailed spiders (n=6 is having Harsilia savignyi Lucas, 1836; (n=5 with Araneus diadematus Clerck, 1757 were recorded. It was concluded that 50% of the spiders collected from the study area were venomous. A detail study is required for further exploration of spider fauna of Sheringal, KP, Pakistan with special reference to their taxonomical, physiological and ecological characteristics.

  17. Under the lash: Demodex mites in human diseases.

    Science.gov (United States)

    Lacey, Noreen; Kavanagh, Kevin; Tseng, Scheffer C G

    2009-08-01

    Demodex mites, class Arachnida and subclass Acarina, are elongated mites with clear cephalothorax and abdomens, the former with four pairs of legs. There are more than 100 species of Demodex mite, many of which are obligatory commensals of the pilosebaceous unit of mammals including cats, dogs, sheep, cattle, pigs, goats, deer, bats, hamsters, rats and mice. Among them, Demodex canis, which is found ubiquitously in dogs, is the most documented and investigated. In excessive numbers D. canis causes the inflammatory disease termed demodicosis (demodectic mange, follicular mange or red mange), which is more common in purebred dogs and has a hereditary predisposition in breeding kennels1. Two distinct Demodex species have been confirmed as the most common ectoparasite in man. The larger Demodex folliculorum, about 0.3-0.4 mm long, is primarily found as a cluster in the hair follicle (Figure 1a), while the smaller Demodex brevis, about 0.2-0.3 mm long with a spindle shape and stubby legs, resides solitarily in the sebaceous gland (Figure 1b). These two species are also ubiquitously found in all human races without gender preference. The pathogenic role of Demodex mites in veterinary medicine is not as greatly disputed as in human diseases. In this article, we review the key literature and our joint research experience regarding the pathogenic potential of these two mites in causing inflammatory diseases of human skin and eye. We hope that the evidence summarized herein will invite readers to take a different look at the life of Demodex mites in several common human diseases.

  18. Air-conditioner filters enriching dust mites allergen.

    Science.gov (United States)

    Zhan, Xiaodong; Li, Chaopin; Xu, Haifeng; Xu, Pengfei; Zhu, Haibin; Diao, Jidong; Li, Na; Zhao, Beibei

    2015-01-01

    We detected the concentration of dust mites allergen (Der f1 & Der p1) in the air of different places before and after the starting of air-conditioners in Wuhu City, Anhui, China, and to discuss the relation between the dust mites allergen in air-conditioner filters and the asthma attack. The dust samples were collected from the air-conditioner filters in dining rooms, shopping malls, hotels and households respectively. Concentrations of dust mites major group allergen 1 (Der f 1, Der p1) were detected with enzyme linked immunosorbent assay (ELISA), and the dust mite immune activities were determined by dot-ELISA. The concentration of Der f1 in dining rooms, shopping malls, hotels and households was 1.52 μg/g, 1.24 μg/g, 1.31 μg/g and 1.46 μg/g respectively, and the concentration of Der p1 in above-mentioned places was 1.23 μg/g, 1.12 μg/g, 1.16 μg/g and 1.18 μg/g respectively. The concentration of Der f1 & Der p1 in air was higher after the air-conditioners starting one hours later, and the difference was significant (Pair-conditioner filters can enrich dust mites major group allergen, and the allergens can induce asthma. The air-conditioner filters shall be cleaned or replaced regularly to prevent or reduce accumulation of the dust mites and its allergens.

  19. Synthetic Spider Silk Production on a Laboratory Scale

    Science.gov (United States)

    Hsia, Yang; Gnesa, Eric; Pacheco, Ryan; Kohler, Kristin; Jeffery, Felicia; Vierra, Craig

    2012-01-01

    As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation biomaterials with high performance properties. The development of these new structural materials must be rapid, cost-efficient and involve processing methodologies and products that are environmentally friendly and sustainable. Spiders spin a multitude of different fiber types with diverse mechanical properties, offering a rich source of next generation engineering materials for biomimicry that rival the best manmade and natural materials. Since the collection of large quantities of natural spider silk is impractical, synthetic silk production has the ability to provide scientists with access to an unlimited supply of threads. Therefore, if the spinning process can be streamlined and perfected, artificial spider fibers have the potential use for a broad range of applications ranging from body armor, surgical sutures, ropes and cables, tires, strings for musical instruments, and composites for aviation and aerospace technology. In order to advance the synthetic silk production process and to yield fibers that display low variance in their material properties from spin to spin, we developed a wet-spinning protocol that integrates expression of recombinant spider silk proteins in bacteria, purification and concentration of the proteins, followed by fiber extrusion and a mechanical post-spin treatment. This is the first visual representation that reveals a step-by-step process to spin and analyze artificial silk fibers on a laboratory scale. It also provides details to minimize the introduction of variability among fibers spun from the same spinning dope. Collectively, these methods will propel the process of artificial silk production, leading to higher quality fibers that surpass natural spider silks. PMID:22847722

  20. Brown Spider (Loxosceles genus Venom Toxins: Tools for Biological Purposes

    Directory of Open Access Journals (Sweden)

    Andrea Senff-Ribeiro

    2011-03-01

    Full Text Available Venomous animals use their venoms as tools for defense or predation. These venoms are complex mixtures, mainly enriched of proteic toxins or peptides with several, and different, biological activities. In general, spider venom is rich in biologically active molecules that are useful in experimental protocols for pharmacology, biochemistry, cell biology and immunology, as well as putative tools for biotechnology and industries. Spider venoms have recently garnered much attention from several research groups worldwide. Brown spider (Loxosceles genus venom is enriched in low molecular mass proteins (5–40 kDa. Although their venom is produced in minute volumes (a few microliters, and contain only tens of micrograms of protein, the use of techniques based on molecular biology and proteomic analysis has afforded rational projects in the area and permitted the discovery and identification of a great number of novel toxins. The brown spider phospholipase-D family is undoubtedly the most investigated and characterized, although other important toxins, such as low molecular mass insecticidal peptides, metalloproteases and hyaluronidases have also been identified and featured in literature. The molecular pathways of the action of these toxins have been reported and brought new insights in the field of biotechnology. Herein, we shall see how recent reports describing discoveries in the area of brown spider venom have expanded biotechnological uses of molecules identified in these venoms, with special emphasis on the construction of a cDNA library for venom glands, transcriptome analysis, proteomic projects, recombinant expression of different proteic toxins, and finally structural descriptions based on crystallography of toxins.

  1. Global patterns of guild composition and functional diversity of spiders.

    Directory of Open Access Journals (Sweden)

    Pedro Cardoso

    Full Text Available The objectives of this work are: (1 to define spider guilds for all extant families worldwide; (2 test if guilds defined at family level are good surrogates of species guilds; (3 compare the taxonomic and guild composition of spider assemblages from different parts of the world; (4 compare the taxonomic and functional diversity of spider assemblages and; (5 relate functional diversity with habitat structure. Data on foraging strategy, prey range, vertical stratification and circadian activity was collected for 108 families. Spider guilds were defined by hierarchical clustering. We searched for inconsistencies between family guild placement and the known guild of each species. Richness and abundance per guild before and after correcting guild placement were compared, as were the proportions of each guild and family between all possible pairs of sites. Functional diversity per site was calculated based on hierarchical clustering. Eight guilds were discriminated: (1 sensing, (2 sheet, (3 space, and (4 orb web weavers; (5 specialists; (6 ambush, (7 ground, and (8 other hunters. Sixteen percent of the species richness corresponding to 11% of all captured individuals was incorrectly attributed to a guild by family surrogacy; however, the correlation of uncorrected vs. corrected guilds was invariably high. The correlation of guild richness or abundances was generally higher than the correlation of family richness or abundances. Functional diversity was not always higher in the tropics than in temperate regions. Families may potentially serve as ecological surrogates for species. Different families may present similar roles in the ecosystems, with replacement of some taxa by other within the same guild. Spiders in tropical regions seem to have higher redundancy of functional roles and/or finer resource partitioning than in temperate regions. Although species and family diversity were higher in the tropics, functional diversity seems to be also

  2. SPIDERS (ARANEI OF THE REPUBLIC OF SOUTH OSSETIA

    Directory of Open Access Journals (Sweden)

    Alexander V. Ponomarev

    2015-01-01

    Full Text Available Aim. Until recently, spider fauna of the Republic of South Ossetia has been the least studied among the regional araneofaunas of the Caucasus. According to the literature data, as little as 30 spider species have been known from the republic’s territory (Mkheidze, 1997, Mikhailov, 1990; Ponomarev, Dvadnenko, 2013; Trilicauscas, Komarov, 2014. Therefore, the aim of the present article is to summarize available data on the spider fauna of South Ossetia.Location. Republic of South Ossetia.Methods. The material was collected in various districts of South Ossetia in 2011-2014 by Yu.E. Komarov. Mainly, the collecting was performed in the city of Tskhinvali and its environs, and in the South Ossetian State Reserve. Spiders were sampled with pitfall traps and sweep netting. The time of traps’ exposure is April–December.Results and main conclusions. To date, the spider fauna of the Republic of South Ossetia includes 230 species from 29 families. 222 species were registered by the authors, eight species (Clubiona pseudosimilis, Gnaphosa lugubris, Linyphia hortensis, Neriene peltata, Geolycosa vultuosa, Pardosa azerifalcata, Ero aphana, and Philodromus rufus are known from the literature only. Seven species are new to the Caucasus (Clubiona pseudosimilis, Gnaphosa lugubris, Linyphia hortensis, Neriene peltata, Geolycosa vultuosa, Pardosa azerifalcata, Ero aphana, and Philodromus rufus. Of these, two species were known earlier only from Turkey (Pardosa consimilis, Ozyptila spirembolus, and one species (Tegenaria pseudolyncea only from Azerbaijan. Against the background of the widespread species predominance, the Caucasian element is small and presented by twelve species (Tegenaria pseudolyncea, Dysdera tkibuliensis, Haplodrassus caucasius, Zelotes khostensis, Mansuphantes ovalis, Sintula oseticus, Tenuiphantes teberdaensis, Pardosa azerifalcata, P. caucasica, Piratula hurkai, Trochosa cachetiensis, and Xysticus ukrainicus.

  3. Competitive interactions between a native spider (Frontinella communis, Araneae: Linyphiidae) and an invasive spider (Linyphia triangularis, Araneae: Linyphiidae)

    Science.gov (United States)

    Bednarski, Julie V.; Ginsberg, Howard S.; Jakob, Elizabeth M.

    2010-01-01

    There are numerous reports of spiders that have become established outside of their native ranges, but few studies examine their impact on native spiders. We examined the effect of the European hammock spider Linyphia triangularis (Araneae, Linyphiidae) on the native bowl-and-doily spider Frontinella communis (Araneae, Linyphiidae) in Acadia National Park, Maine, USA. First, we added L. triangularis to established plots of F. communis. Significantly more F. communis abandoned their webs when L. triangularis were added compared to control plots. Second, we tested whether F. communis were deterred from building webs in areas where L. triangularis was established. Significantly fewer F. communis built webs on plots with L. triangularis than on control plots. In both experiments, L. triangularis sometimes took over webs of F. communis or incorporated F. communis webs into their own webs, but F. communisnever took over or incorporated L. triangularis webs. Competition between L. triangularis and F. communis for both webs and web sites may contribute to the decline of F. communis.

  4. Differential water mite parasitism, phenoloxidase activity, and resistance to mites are unrelated across pairs of related damselfly species.

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    Julia J Mlynarek

    Full Text Available Related host species often demonstrate differences in prevalence and/or intensity of infection by particular parasite species, as well as different levels of resistance to those parasites. The mechanisms underlying this interspecific variation in parasitism and resistance expression are not well understood. Surprisingly, few researchers have assessed relations between actual levels of parasitism and resistance to parasites seen in nature across multiple host species. The main goal of this study was to determine whether interspecific variation in resistance against ectoparasitic larval water mites either was predictive of interspecific variation in parasitism for ten closely related species of damselflies (grouped into five "species pairs", or was predicted by interspecific variation in a commonly used measure of innate immunity (total Phenoloxidase or potential PO activity. Two of five species pairs had interspecific differences in proportions of individuals resisting larval Arrenurus water mites, only one of five species pairs had species differences in prevalence of larval Arrenurus water mites, and another two of five species pairs showed species differences in mean PO activity. Within the two species pairs where species differed in proportion of individuals resisting mites the species with the higher proportion did not have correspondingly higher PO activity levels. Furthermore, the proportion of individuals resisting mites mirrored prevalence of parasitism in only one species pair. There was no interspecific variation in median intensity of mite infestation within any species pair. We conclude that a species' relative ability to resist particular parasites does not explain interspecific variation in parasitism within species pairs and that neither resistance nor parasitism is reflected by interspecific variation in total PO or potential PO activity.

  5. Invited review current progress and limitations of spider silk for biomedical applications.

    Science.gov (United States)

    Widhe, Mona; Johansson, Jan; Hedhammar, My; Rising, Anna

    2012-06-01

    Spider silk is a fascinating material combining remarkable mechanical properties with low density and biodegradability. Because of these properties and historical descriptions of medical applications, spider silk has been proposed to be the ideal biomaterial. However, overcoming the obstacles to produce spider silk in sufficient quantities and in a manner that meets regulatory demands has proven to be a difficult task. Also, there are relatively few studies of spider silk in biomedical applications available, and the methods and materials used vary a lot. Herein we summarize cell culture- and in vivo implantation studies of natural and synthetic spider silk, and also review the current status and future challenges in the quest for a large scale production of spider silk for medical applications. Copyright © 2011 Wiley Periodicals, Inc.

  6. Research on Artificial Spider Web Model for Farmland Wireless Sensor Network

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    Jun Wang

    2018-01-01

    Full Text Available Through systematic analysis of the structural characteristics and invulnerability of spider web, this paper explores the possibility of combining the advantages of spider web such as network robustness and invulnerability with farmland wireless sensor network. A universally applicable definition and mathematical model of artificial spider web structure are established. The comparison between artificial spider web and traditional networks is discussed in detail. The simulation result shows that the networking structure of artificial spider web is better than that of traditional networks in terms of improving the overall reliability and invulnerability of communication system. A comprehensive study on the advantage characteristics of spider web has important theoretical and practical significance for promoting the invulnerability research of farmland wireless sensor network.

  7. How informative are case studies of spider bites in the medical literature?

    Science.gov (United States)

    Stuber, Marielle; Nentwig, Wolfgang

    2016-05-01

    We analyzed the reliability and information content of 134 medical case studies on spider bites, published in 91 journal articles. Overall, we found that only 22% of these studies fulfilled the criteria for a verified spider bite. This means that the majority of such case studies cannot be attributed to a given spider species and usually not even to a spider. Their scientific value is negligible, moreover, such publications are even dangerous because they suggest incorrect conclusions. Secondly, we found that such case studies usually do not follow an obvious structure and many details on the development of symptoms, therapy and healing process are widely lacking. So even for verified spider bites, the comparability of case studies is limited. We discuss the obvious failure of a reviewing process for case studies and give recommendations how to increase the currently low information content of medical case studies on spider bites. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Plastic material investment in load-bearing silk attachments in spiders.

    Science.gov (United States)

    Wolff, Jonas O; Jones, Braxton; Herberstein, Marie E

    2018-05-17

    The nature and size of attachments is a fundamental element of animal constructions. Presumably, these adhesive structures are plastically deployed to balance material investment and attachment strength. Here we studied plasticity in dragline anchorages of the golden orb web spider, Nephila plumipes. Specifically, we predict that spiders adjust the size and structure of dragline anchorages with load, i.e. spider mass. Mass was manipulated by attaching lead pieces to the spider's abdomen resulting in a 50 percent increase in mass. Loaded spiders spun larger but structurally similar thread anchorages than unloaded spiders. Thus, the spinning program that determines the overall anchor structure is highly stereotypic, and flexibility is introduced through varying the anchor size by increasing material investment. Our study showcases substrate attachments as suitable models to investigate the interplay between innate and changeable elements in the economy of building behaviours. Copyright © 2018 Elsevier GmbH. All rights reserved.

  9. Rapid visuomotor processing of phobic images in spider- and snake-fearful participants.

    Science.gov (United States)

    Haberkamp, Anke; Schmidt, Filipp; Schmidt, Thomas

    2013-10-01

    This study investigates enhanced visuomotor processing of phobic compared to fear-relevant and neutral stimuli. We used a response priming design to measure rapid, automatic motor activation by natural images (spiders, snakes, mushrooms, and flowers) in spider-fearful, snake-fearful, and control participants. We found strong priming effects in all tasks and conditions; however, results showed marked differences between groups. Most importantly, in the group of spider-fearful individuals, spider pictures had a strong and specific influence on even the fastest motor responses: Phobic primes entailed the largest priming effects, and phobic targets accelerated responses, both effects indicating speeded response activation by phobic images. In snake-fearful participants, this processing enhancement for phobic material was less pronounced and extended to both snake and spider images. We conclude that spider phobia leads to enhanced processing capacity for phobic images. We argue that this is enabled by long-term perceptual learning processes. © 2013.

  10. Evolutionary morphology of the hemolymph vascular system of basal araneomorph spiders (Araneae: Araneomorphae).

    Science.gov (United States)

    Huckstorf, Katarina; Michalik, Peter; Ramírez, Martín; Wirkner, Christian S

    2015-11-01

    The superfamily Austrochiloidea (Austrochilidae and Gradungulidae) take a pivotal position in araneomorph spider phylogeny. In this discussion crevice weaver spiders (Filistatidae) are of equal interest. Especially data from these phylogenetically uncertain yet basal off branching groups can enlighten our understanding on the evolution of organ systems. In the course of a survey on the evolutionary morphology of the circulatory system in spiders we therefore investigated the hemolymph vascular system in two austrochiloid and one filistatid species. Additionally some data on a hypochilid and a gradungulid species are included. Using up-to-date morphological methods, the vascular systems in these spiders are visualized three dimensionally. Ground pattern features of the circulatory systems in austrochiloid spiders are presented and the data discussed along recent lines of phylogenetic hypotheses. Special topics highlighted are the intraspecific variability of the origins of some prosomal arteries and the evolutionary correlation of respiratory and circulatory systems in spiders. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Weed management practices affect the diversity and relative abundance of physic nut mites.

    Science.gov (United States)

    Saraiva, Althiéris de Sousa; Sarmento, Renato A; Erasmo, Eduardo A L; Pedro-Neto, Marçal; de Souza, Danival José; Teodoro, Adenir V; Silva, Daniella G

    2015-03-01

    Crop management practices determine weed community, which in turn may influence patterns of diversity and abundance of associated arthropods. This study aimed to evaluate whether local weed management practices influence the diversity and relative abundance of phytophagous and predatory mites, as well as mites with undefined feeding habits--of the families Oribatidae and Acaridae--in a physic nut (Jatropha curcas L.) plantation subjected to (1) within-row herbicide spraying and between-row mowing; (2) within-row herbicide spraying and no between-row mowing; (3) within-row weeding and between-row mowing; (4) within-row weeding and no between-row mowing; and (5) unmanaged (control). The herbicide used was glyphosate. Herbicide treatments resulted in higher diversity and relative abundance of predatory mites and mites with undefined feeding habit on physic nut shrubs. This was probably due to the toxic effects of the herbicide on mites or to removal of weeds. Within-row herbicide spraying combined with between-row mowing was the treatment that most contributed to this effect. Our results show that within-row weeds harbor important species of predatory mites and mites with undefined feeding habit. However, the dynamics of such mites in the system can be changed according to the weed management practice applied. Among the predatory mites of the family Phytoseiidae Amblydromalus sp. was the most abundant, whereas Brevipalpus phoenicis was the most frequent phytophagous mite and an unidentified oribatid species was the most frequent mite with undefined feeding habit.

  12. A feeding protocol for delivery of agents to assess development in Varroa mites.

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    Ana R Cabrera

    Full Text Available A novel feeding protocol for delivery of bio-active agents to Varroa mites was developed by providing mites with honey bee larva hemolymph supplemented with cultured insect cells and selected materials delivered on a fibrous cotton substrate. Mites were starved, fed on treated hemolymph to deliver selected agents and then returned to bee larvae. Transcript levels of two reference genes, actin and glyceraldehyde 3-phosphate dehydrogenase (GAPDH, as well as for nine selected genes involved in reproductive processes showed that the starvation and feeding protocol periods did not pose a high level of stress to the mites as transcript levels remained comparable between phoretic mites and those completing the protocol. The feeding protocol was used to deliver molecules such as hormone analogs or plasmids. Mites fed with Tebufenozide, an ecdysone analog, had higher transcript levels of shade than untreated or solvent treated mites. In order to extend this feeding protocol, cultured insect cells were incorporated to a final ratio of 1 part cells and 2 parts hemolymph. Although supplementation with Bombyx mori Bm5 cells increased the amount of hemolymph consumed per mite, there was a significant decrease in the percentage of mites that fed and survived. On the other hand, Drosophila melanogaster S2 cells reduced significantly the percentage of mites that fed and survived as well as the amount of hemolymph consumed. The feeding protocol provides a dynamic platform with which to challenge the Varroa mite to establish efficacy of control agents for this devastating honey bee pest.

  13. Feather mites (Acari, Astigmata from Azorean passerines (Aves, Passeriformes: lower species richness compared to European mainland

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    Rodrigues Pedro

    2015-01-01

    Full Text Available Ten passerine species were examined on three islands of the Azores (North Atlantic during 2013 and 2014 in order to identify their feather mite assemblages. We recorded 19 feather mite species belonging to four families of the superfamily Analgoidea (Analgidae, Proctophyllodidae, Psoroptoididae and Trouessartiidae. A high prevalence of feather mite species was recorded on the majority of the examined host species. Only three passerine species (Sylvia atricapilla, Regulus regulus and Serinus canaria presented the same full complex of mite species as commonly occurs in the plumage of their closest relatives in continental Europe. Passer domesticus presented the same limited fauna of feather mites living in the plumage as do its co-specifics in continental Europe. Carduelis carduelis bears the same feather mite species as do most of its continental populations in Europe, but it lacks one mite species occurring on this host in Egypt. Turdus merula, Pyrrhula murina and Fringilla coelebs are missing several mite species common to their continental relatives. This diminution could be explained by the founder effect, whereby a limited number of colonizing individuals did not transport the full set of feather mite species, or by the extinction of some mite species after initially having reached the Azores. The only individual of Motacilla cinerea sampled in this study presented a new host record for the mite species Trouessartia jedliczkai.

  14. Ecological Factors Determining Abundance of Parasitic Mites on Aedes spp. Larvae

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    Nurhadi Eko Firmansyah

    2017-12-01

    Full Text Available Ability to infestation and abundance of parasitic mites in Aedes spp. larvae cannot be separated from the influence of various factors. Ecological factors have been suggested to play a role determine the presence of parasitic mites that under certain conditions become a key factor in determining the abundance of parasitic mites on Aedes spp. larvae. The aim of this study to determine the ecological factors affect the abundance of parasitic mites on Aedes spp. larvae in Bogor Regency. Capturing of Aedes spp. larvae was performed directly on the habitats found in indoor and outdoor. Capturing mites in the body of Aedes spp. larvae was performed using insect forceps. Ecological factors measured were dissolved oxygen (DO, pH, temperature, and total dissolved solid (TDS. The influence of ecological factors was analyzed using regression and correlation analysis. The result of mite identification has been obtained three species of mites that are Halacarus sp., Histiostoma sp., and Hydrozetes sp. The result indicated that total dissolved solid (TDS and temperature was the factors that determined the abundance of mites. The factors of pH, and dissolved oxygen (DO did not determine the abundance of parasitic mites of Aedes spp. larvae. The research result can be further developed as a new alternative to Dengue Hemorraghic Fever control and provide information on parasitic mites that infest Aedes spp. larvae. In addition, this results become an early step in controlling of Aedes spp. strategy platform by the parasitic mites.

  15. Nasal mites (Mesostigmata, Rhinonyssidae in Sternidae (Aves: Charadriiformes on the southern Coast of Brazil

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    Diego Silva da Silva

    2018-02-01

    Full Text Available Abstract Six species of birds of the family Sternidae are often found on the southern coast of South America. Sterna trudeaui, S. hirundinacea, Thalasseus maximus, T. acuflavidus and Sternula superciliaris are South American residents and Sterna hirundo, a Nearctic migrant. At least 500 species of nasal mites have been described around the world, and Rhinonyssidae is the most diverse family. These mites are bloodsucking endoparasites that inhabit the respiratory system of birds. This study aimed to report on occurrences of nasal mites in Sternidae on the southern coast of Brazil. Of the 106 birds analyzed, 8.5% (9 birds were parasitized by nasal mites. This report provides the first record in the Neotropical region for two mite species, Sternostoma boydi and Larinyssus orbicularis parasitizing Thalasseus acuflavidus and Sternula superciliaris. No nasal mites were found in Sterna trudeaui or Thalasseus maximus. One host individual (T. acuflavidus was parasitized by two species of nasal mites, S. boydi and L. orbicularis.

  16. Origins of asexuality in Bryobia mites (Acari: Tetranychidae)

    NARCIS (Netherlands)

    Ros, V.I.D.; Breeuwer, J.A.J.; Menken, S.B.J.

    2008-01-01

    Background Obligate asexual reproduction is rare in the animal kingdom. Generally, asexuals are considered evolutionary dead ends that are unable to radiate. The phytophagous mite genus Bryobia contains a large number of asexual species. In this study, we investigate the origin and evolution of

  17. Control of house-dust mites with home disinfectants

    NARCIS (Netherlands)

    Schober, G.; Wetter, G.; Bischoff, E.; Bronswijk, van J.E.M.H.; Kniest, F.M.

    1987-01-01

    Chemical disinfectants and biocidal preparations used in households were tested in the laboratory for their ability to kill the house-dust miteDermatophagoides farinae. Batches of ten specimens were soaked in aqueous solutions or suspensions containing 0.0, 0.1, 0.3, 1.0, 3.0 and 10.0% (by volume)

  18. Fungi and mites on humid indoor walls : a laboratory study

    NARCIS (Netherlands)

    Koren, L.G.H.; Kort, H.S.M.; Siebers, Rob; Cunningham, M.; Fitzharris, P.

    2000-01-01

    The potential allergen source formed by mites and fungi developing on walls has been studied in a semi-natural model. Gypsum and wooden pieces, representing indoor walls, were artificially soiled with one of two different organic compounds, a yeast/vegetable mixture (Mannite) or a red currant juice

  19. Role of Predatory Mites in Persistent Nonoccupational Allergic Rhinitis

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    Paloma Poza Guedes

    2016-01-01

    Full Text Available Mites can sensitize and induce atopic disease in predisposed individuals and are an important deteriorating factor in patients with allergic rhinitis, asthma, and atopic dermatitis. Although Pyroglyphidae mites have been extensively studied, very scarce reports are available on Cheyletidae spp. especially regarding human respiratory pathology. The main objective of the present study is to investigate the clinical role of this predator mite (Cheyletus eruditus as a respiratory antigen in a selected sensitized human population. Fifty-two adult patients were recruited from the outpatient allergy clinic to assess their eligibility for the study. The thirty-seven subjects with persistent allergic rhinitis (PAR who fulfilled the ARIA criteria had a positive IgE response confirmed by skin prick test (SPT to C. eruditus. Only those individuals (37/47 with a positive SPT to C. eruditus showed a positive nasal provocation test (NPT, while 10 patients with nonallergic mild-to-moderate persistent rhinitis, control group, had a negative NPT with C. eruditus. The present paper describes a new role for the predator mite Cheyletus eruditus as a respiratory allergen in a selected subset of patients in a subtropical environment afflicted with persistent nonoccupational allergic rhinitis.

  20. Stability evaluation of house dust mite vaccines for sublingual immunotherapy

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    MARIJA GAVROVIĆ-JANKULOVIĆ

    2010-01-01

    Full Text Available Allergen-specific immunotherapy with house dust mite (HDM allergen extracts can effectively alleviate the symptoms of allergic rhinitis and asthma. The efficacy of the immunotherapeutic treatment is highly dependent on the quality of house dust mite vaccines. This study was performed to assess the stability of house dust mite allergen vaccines prepared for sublingual immunotherapy. Lyophilized Dermatophagoides pteronyssinus (Dpt mite bodies were the starting material for the production of sublingual vaccines in four therapeutic concentrations. The stability of the extract for vaccine production, which was stored below 4 °C for one month, showed consistence in the protein profile in SDS PAGE. ELISA-inhibition showed that the potencies of Dpt vaccines during a 12 month period were to 65–80 % preserved at all analyzed therapeutic concentrations. This study showed that glycerinated Dpt vaccines stored at 4 °C preserved their IgE-binding potential during a 12 month period, implying their suitability for sublingual immunotherapeutic treatment of HDM allergy.