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Sample records for ground spider family

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

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    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.

  2. Ground Spider Guilds and Functional Diversity in Native Pine Woodlands and Eucalyptus Plantations.

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    Corcuera, Pablo; Valverde, Pedro Luis; Jiménez, María Luisa; Ponce-Mendoza, Alejandro; De la Rosa, Gabriela; Nieto, Gisela

    2016-04-01

    Vegetation structure and floristics have a strong influence on the relative abundance of spider guilds and functional diversity of terrestrial arthropods. Human activities have transformed much of the temperate woodlands. The aim of this study was to test five predictions related to the guild distribution and functional diversity of the ground spider communities of Eucalyptus plantations and native pine woodlands in western Mexico. Spiders were collected every fortnight from September to November from 15 pitfalls positioned in each of the eight sites. We also assessed the cover of grasses, herbs, shrubs, and leaf litter in each site. We found that the abundances of ground hunters and sheet weavers between plantations and pine woodlands were different. Nevertheless, there was not a consistent difference between sites of each of the vegetation types. Most species of ground hunters, sheet web weavers, and many other hunters were associated with litter and the grass cover. Nonetheless, in some cases, species of different families belonging to the same guild responded to different variables. Wolf spiders were related to the grass Aristida stricta Micheaux, 1803, while the species of the other families of ground hunters were associated with leaf litter. One Eucalyptus plantation and one pine woodland had the highest functional diversity of all sites. These sites have a well developed litter and grass cover. Our study suggests that the abundance of litter and a high cover of grasses explain the occurrence of species with different traits, and these habitat components results in a high functional diversity.

  3. 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

  4. Contribution to the knowledge of the Southeast Asian spiders of the families Pacullidae and Tetrablemmidae

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    Deeleman-Reinhold, C.L.

    1980-01-01

    INTRODUCTION Among the spiders, obtained during our 1979 collecting trip to Borneo by sieving leaf-litter in various forest types, the armored spiders of the families Pacullidae and Tetrablemmidae were among the most numerous and diversified. The excellent paper by Shear ( 1978) treating these

  5. Male palp organ morphology of three species of ground spiders (Araneae, Gnaphosidae

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    Zakharov, Boris

    2013-06-01

    Full Text Available A detailed morphological account of the male copulatory organs of three species of ground spiders, Sergiolus capulatus, Herpyllus propinquus and Callilepis pluto (Araneae, Gnaphosidae, is presented. The large sclerites (subtegulum, tegulum and embolus appear to be homologous in all spiders. Sergiolus and Zelanda have a plesiomorphic palp organization. The increased complexity in the male bulb organization creates a locking mechanism that fixes the male palp position during intercourse in Callilepis, as well as in Encoptarthria, Trachyzelotes and Zelotes. The palp of Herpyllus, together with Anzacia, Drassodes and Intruda, demonstrates progressive modification of the male bulb.

  6. INSECTICIDE RESISTANCE IN THE GROUND SPIDER, Pardosa sumatrana (THORELL, 1890; ARANEAE: LYCOSIDAE).

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    Tahir, Hafiz Muhammad; Khizar, Farva; Naseem, Sajida; Yaqoob, Rabia; Samiullah, Khizar

    2016-09-01

    Elevated levels of insecticides detoxifying enzymes, such as esterases, glutathione S-transferases (GSTs), and cytochrome P-450 monooxygenases, act in the resistance mechanisms in insects. In the present study, levels of these enzymes in the insecticide-resistant ground spider Pardosa sumatrana (Thorell, 1890) were compared with a susceptible population (control) of the same species. Standard protocols were used for biochemical estimation of enzymes. The results showed significantly higher levels of nonspecific esterases and monooxygenases in resistant spiders compared to controls. The activity of GSTs was lower in the resistant spiders. Elevated levels of nonspecific esterases and monooxygenases suggest their role in metabolic resistance in P. sumatrana. The reduced levels of total protein contents revealed its possible consumption to meet energy demands.

  7. A faunistic study on ground-dwelling spiders (Araneae in the Tirana district, Albania

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    Vrenozi, Blerina

    2012-12-01

    Full Text Available Spiders from the Tirana district of Albania were investigated. Currently, 78 species from 24 families and a collection of 400 specimens from January to August 2010 were recorded for Tirana. A total of 32 new records for the Albanian fauna are included in the present paper. Agraecina lineata (Simon, 1878 is the first record for the Balkan Peninsula. Saitis graecus Kulczyński, 1905 was known before only from Greece and Bulgaria. Presently, 373 spider species are known for Albania.

  8. Spider assemblages in the overstory, understory, and ground layers of managed stands in the western boreal mixedwood forest of Canada.

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    Pinzon, Jaime; Spence, John R; Langor, David W

    2011-08-01

    Logging is the main human disturbance in the boreal forest; thus, understanding the effects of harvesting practices on biodiversity is essential for a more sustainable forestry. To assess changes in spider composition because of harvesting, samples were collected from three forest layers (overstory, understory, and ground) of deciduous and conifer dominated stands in the northwestern Canadian boreal mixedwood forest. Spider assemblages and feeding guild composition were compared between uncut controls and stands harvested to 20% retention. In total, 143 spider species were collected, 74 from the ground, 60 from the understory, and 71 from the overstory, and species composition of these three pools differed considerably among layers. Distinctive spider assemblages were collected from the canopy of each forest cover type but these were only slightly affected by harvesting. However, logging had a greater impact on the species composition in the understory and ground layers when compared with unharvested controls. Guild structure differed among layers, with wandering and sheet-weaving spiders dominant on the ground while orb-weaving and ambush spiders were better represented in the understory and overstory, respectively. Given the ecological importance of spiders and the expectation of faunal changes with increased harvesting, further efforts toward the understanding of species composition in higher strata of the boreal forest are needed.

  9. Ground-living spiders (Araneae at polluted sites in the Subarctic

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    Koponen, Seppo

    2011-01-01

    Full Text Available Spiders were studied around the Pechenganikel smelter combine, Kola Peninsula, north-western Russia. The average spider density was 6-fold greater and the density of Linyphiidae specimens 11.5-fold higher at slightly polluted sites, compared with heavily polluted sites. Altogether, 18 species from 10 families were found at heavily polluted sites, the theridiid Robertus scoticus clearly dominating (23.3 % of identifiable specimens, also Neon reticulatus (9.6 %, Thanatus formicinus (9.6 % and Xysticus audax (8.2 % were abundant. The most numerous among 58 species found at slightly polluted sites were Tapinocyba pallens (18.5 %, Robertus scoticus (13.7 %, Maso sundevalli (9.5 % and Alopecosa aculeata (8.2 %. The family Linyphiidae dominated at slightly polluted sites, 64 % of species and 60 % of individuals; compared with heavily polluted sites, 23 % and 38 % respectively.

  10. The spider family Selenopidae (Arachnida, Araneae in Australia and Asia

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    Sarah Crews

    2011-05-01

    Full Text Available The spider family Selenopidae Simon occurs worldwide in tropical and subtropical regions, currently containing nearly 200 species in five genera. We relimit and revise the family to include four new genera and 27 new species from Australia and Asia. The family Selenopidae is redefined, as are the genera Anyphops Benoit, Garcorops Corronca, Hovops Benoit, Selenops Latreille, and Siamspinops Dankittipakul and Corronca, to accommodate the new genera and to correct previous errors in the definition. The species of Selenops that occur throughout India and China are also reviewed. Three species occur in China: S. bursarius Karsch, also known from Japan, Korea and Taiwan, S. ollarius Zhu, Sha, and Chen, and S. radiatus Latreille, the type of the genus and most widespread selenopid. Selenops cordatus Zhu, Sha, and Chen is recognized as a junior synonym of S. radiatus, syn. n. Amamanganops gen. n. is monotypic, with A. baginawa sp. n., and is known only from the Philippine island of Mindoro. Godumops gen. n. is monotypic, with G. careus sp. n., and is known only from Papua New Guinea. Karaops gen. n. occurs throughout Australia and has 24 species: K. australiensis (L. Koch comb. n., K. gangarie sp. n., K. monteithi sp. n., K. alanlongbottomi sp. n., K. keithlongbottomi sp. n., K. larryoo sp. n., K. jarrit sp. n., K. marrayagong sp. n., K. raveni sp. n., K. badgeradda sp. n., K. burbidgei sp. n., K. karrawarla sp. n., K. julianneae sp. n., K. martamarta sp. n., K. manaayn sp. n., K. vadlaadambara sp. n., K. pilkingtoni sp. n., K. deserticola sp. n., K. ngarutjaranya sp. n., K. francesae sp. n., K. toolbrunup sp. n., the type species K. ellenae sp. n., K. jenniferae sp. n., and K. dawara sp. n. The genus Makdiops gen. n. contains five species from India and Nepal: M. agumbensis (Tikader, comb. n., the type of the genus M. mahishasura sp. n., M. montigenus (Simon, comb. n., M. nilgirensis (Reimoser comb. n., and M. shiva sp. n. The genus Pakawops gen. n. is

  11. Ground-living spiders in wooded habitats under human influence on an island in Finland

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    Koponen, Seppo

    2013-06-01

    Full Text Available Spiders were collected by pitfall traps in the south-western archipelago of Finland. Wooded study habitats on a small-sized (1.2 km2 island were: 1 natural open ash grove, 2 dense mixed grove (old overgrown wooded meadow, 3 wooded aspen pasture and 4 wooded meadow, both restored ten years earlier, 5 natural wooded meadow. Highest species and family numbers were found at the natural sites (1 and 5 and the lowest in the dense grove (site 2. Linyphiidae dominated, both at species and individual level, in the groves. Lycosidae were abundant on the wooded meadows and Gnaphosidae on the wooded pasture. The highest faunal similarities were between the groves (70 % species in common and between the wooded meadows (64 %. The lowest similarity was found between the dense grove (17 % and the ash grove (23 % with the aspen pasture. Ten years after clearing, sites 3 and 4 had diverse spider faunas. The fauna at site 4 resembled that on the corresponding natural site (5, thus showing restoration success. Altogether 84 species of spiders were caught. The proportion of Gnaphosidae (16 species found is high. Most species found in the study are common in south-western Finland and many occur across the whole country. Pardosa lugubris was most dominant at three sites, P. pullata and Diplostyla concolor both at one site. Two species, Enoplognatha thoracica and Micaria fulgens, are included in the Finnish Red Data Book.

  12. Bartonella henselae infection in a family experiencing neurological and neurocognitive abnormalities after woodlouse hunter spider bites

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    2013-01-01

    Background Bartonella species comprise a group of zoonotic pathogens that are usually acquired by vector transmission or by animal bites or scratches. Methods PCR targeting the Bartonella 16S-23S intergenic spacer (ITS) region was used in conjunction with BAPGM (Bartonella alpha Proteobacteria growth medium) enrichment blood culture to determine the infection status of the family members and to amplify DNA from spiders and woodlice. Antibody titers to B. vinsonii subsp. berkhoffii (Bvb) genotypes I-III, B. henselae (Bh) and B. koehlerae (Bk) were determined using an IFA test. Management of the medical problems reported by these patients was provided by their respective physicians. Results In this investigation, immediately prior to the onset of symptoms two children in a family experienced puncture-like skin lesions after exposure to and presumptive bites from woodlouse hunter spiders. Shortly thereafter, the mother and both children developed hive-like lesions. Over the ensuing months, the youngest son was diagnosed with Guillain-Barre (GBS) syndrome followed by Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP). The older son developed intermittent disorientation and irritability, and the mother experienced fatigue, headaches, joint pain and memory loss. When tested approximately three years after the woodlouse hunter spider infestation, all three family members were Bartonella henselae seroreactive and B. henselae DNA was amplified and sequenced from blood, serum or Bartonella alpha-proteobacteria (BAPGM) enrichment blood cultures from the mother and oldest son. Also, B. henselae DNA was PCR amplified and sequenced from a woodlouse and from woodlouse hunter spiders collected adjacent to the family’s home. Conclusions Although it was not possible to determine whether the family’s B. henselae infections were acquired by spider bites or whether the spiders and woodlice were merely accidental hosts, physicians should consider the possibility that B

  13. Four new spider species of the family Theridiosomatidae (Arachnida, Araneae from caves in Laos

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    Yucheng Lin

    2014-03-01

    Full Text Available Four new species of the spider family Theridiosomatidae are described from caves in Laos: Alaria cavernicola sp. n. (♂♀, A. navicularis sp. n., (♂♀ A. bicornis sp. n. (♂♀, Chthonopes thakekensis sp. n. (♀. Diagnoses and illustrations for all new taxa are given. All holotypes are deposited in the Senckenberg Research Institute in Frankfurt am Main, Germany (SMF.

  14. Chronic exposure to soil salinity in terrestrial species: Does plasticity and underlying physiology differ among specialized ground-dwelling spiders?

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    Renault, D; Puzin, C; Foucreau, N; Bouchereau, A; Pétillon, J

    2016-07-01

    In salt marshes, the alternation of low and high tides entails rapid shifts of submersion and aerial exposure for terrestrial communities. In these intertidal environments, terrestrial species have to deal with an osmotic loss in body water content and an increase in sodium chloride concentration when salt load increases. In salt marshes, spiders represent an abundant arthropod group, whose physiological ecology in response to variations of soil salinity must be further investigated. In this study, we compared the effect of salinity on the survival and physiology of three species of Lycosidae; two salt marsh species (Arctosa fulvolineata and Pardosa purbeckensis) and one forest species (P. saltans). Spiders were individually exposed at three salinity conditions (0‰, 35‰ and 70‰) and survival, changes in body water content, hemolymph ions (Na(+), Ca(2+), Mg(2+), K(+); ICP-MS technique) and metabolites (mainly amino acids, polyols, sugars; LC and GC techniques) were assessed. The survival of the forest species P. saltans was very quickly hampered at moderate and high salinities. In this spider, variations of hemolymph ions and metabolites revealed a quick loss of physiological homeostasis and a rapid salt-induced dehydration of the specimens. Conversely, high survival durations were measured in the two salt-marsh spiders, and more particularly in A. fulvolineata. In both P. purbeckensis and A. fulvolineata, the proportion of Na(+), Ca(2+), Mg(2+), K(+) remained constant at the three experimental conditions. Accumulation of hemolymph Na(+) and amino acids (mainly glutamine and proline) demonstrated stronger osmoregulatory capacities in these salt-marsh resident spiders. To conclude, even if phylogenetically close (belonging to the same, monophyletic, family), we found different physiological capacities to cope with salt load among the three tested spider species. Nevertheless, physiological responses to salinity were highly consistent with the realized

  15. Dispatch from the field: ecology of ground-web-building spiders with description of a new species (Araneae, Symphytognathidae

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    Jeremy Miller

    2014-03-01

    Full Text Available Crassignatha danaugirangensis sp. n. (Araneae: Symphytognathidae was discovered during a tropical ecology field course held at the Danau Girang Field Centre in Sabah, Malaysia. A taxonomic description and accompanying ecological study were completed as course activities. To assess the ecology of this species, which belongs to the ground-web-building spider community, three habitat types were surveyed: riparian forest, recently inundated riverine forest, and oil palm plantation. Crassignatha danaugirangensis sp. n. is the most abundant ground-web-building spider species in riparian forest; it is rare or absent from the recently inundated forest and was not found in a nearby oil palm plantation. The availability of this taxonomic description may help facilitate the accumulation of data about this species and the role of inundated riverine forest in shaping invertebrate communities.

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

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    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%. 

  17. [Population dynamics of ground carabid beetles and spiders in a wheat field along the wheat-alfalfa interface and their response to alfalfa mowing].

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    Liu, Wen-Hui; Hu, Yi-Jun; Hu, Wen-Chao; Hong, Bo; Guan, Xiao-Qing; Ma, Shi-Yu; He, Da-Han

    2014-09-01

    Taking the wheat-alfalfa and wheat-wheat interfaces as model systems, sampling points were set by the method of pitfall trapping in the wheat field at the distances of 3 m, 6 m, 9 m, 12 m, 15 m, 18 m, 21 m, 24 m, and 27 m from the interface. The species composition and abundance of ground carabid beetles and spiders captured in pitfalls were investigated. The results showed that, to some extent there was an edge effect on species diversity and abundance of ground carabid beetles and spiders along the two interfaces. A marked edge effect was observed between 15 m and 18 m along the alfalfa-wheat interface, while no edge effect was found at a distance over 20 m. The edge effect along the wheat-wheat interface was weaker in comparison to the alfalfa-wheat interface. Alfalfa mowing resulted in the migration of a large number of ground carabid beetles and spiders to the adjacent wheat filed. During ten days since mowing, both species and abundance of ground carabid beetles and spiders increased in wheat filed within the distance of 20 m along the alfalfa-wheat interface. The spatial distribution of species diversity of ground beetles and spiders, together with the population abundance of the dominant Chlaenius pallipes and Pardosa astrigera, were depicted, which could directly indicate the migrating process of natural enemy from alfalfa to wheat field.

  18. Spiders in dermatology.

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    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.

  19. A multilocus molecular phylogeny of the endemic North American camel spider family Eremobatidae (Arachnida: Solifugae).

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    Cushing, Paula E; Graham, Matthew R; Prendini, Lorenzo; Brookhart, Jack O

    2015-11-01

    Camel spiders (Solifugae) are a diverse but poorly studied order of arachnids. No robust phylogenetic analysis has ever been carried out for the order or for any family within the Solifugae. We present a molecular phylogenetic analysis of the endemic North American family Eremobatidae Kraepelin, 1899, the first such analysis of a family of Solifugae. We use a multi-locus exemplar approach using DNA sequences from partial nuclear (28S rDNA and Histone H3) and mitochondrial (16S rRNA and Cytochrome c Oxidase I) gene loci for 81 ingroup exemplars representing all genera of Eremobatidae and most species groups within the genera Eremobates Banks, 1900, Eremochelis Roewer, 1934, and Hemerotrecha Banks, 1903. Maximum Likelihood and two Bayesian analyses consistently recovered the monophyly of Eremobatidae, Eremorhax Roewer, 1934 and Eremothera Muma, 1951 along with a group comprising all subfamily Eremobatinae Kraepelin, 1901 exemplars except Horribates bantai Muma, 1989 and a group comprising all Eremocosta Roewer, 1934 exemplars except Eremocosta acuitalpanensis (Vasquez and Gavin, 2000). The subfamily Therobatinae Muma, 1951 and the genera Chanbria Muma, 1951, Hemerotrecha, Eremochelis, and Eremobates were polyphyletic or paraphyletic. Only the banksi group of Hemerotrecha was monophyletic; the other species groups recognized within Eremobates, Eremochelis, and Hemerotrecha were paraphyletic or polyphyletic. We found no support for the monophyly of the subfamily Therobatinae. A time-calibrated phylogeny dated the most recent common ancestor of extant eremobatids to the late Eocene to early Miocene, with a mean estimate in the late Oligocene (32.2 Ma).

  20. Hunting with sticky tape: functional shift in silk glands of araneophagous ground spiders (Gnaphosidae).

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    Wolff, Jonas O; Řezáč, Milan; Krejčí, Tomáš; Gorb, Stanislav N

    2017-06-15

    Foraging is one of the main evolutionary driving forces shaping the phenotype of organisms. In predators, a significant, though understudied, cost of foraging is the risk of being injured by struggling prey. Hunting spiders that feed on dangerous prey like ants or other spiders are an extreme example of dangerous feeding, risking their own life over a meal. Here, we describe an intriguing example of the use of attachment silk (piriform silk) for prey immobilization that comes with the costs of reduced silk anchorage function, increased piriform silk production and additional modifications of the extrusion structures (spigots) to prevent their clogging. We show that the piriform silk of gnaphosids is very stretchy and tough, which is an outstanding feat for a functional glue. This is gained by the combination of an elastic central fibre and a bi-layered glue coat consisting of aligned nanofibrils. This represents the first tensile test data on the ubiquitous piriform gland silk, adding an important puzzle piece to the mechanical catalogue of silken products in spiders. © 2017. Published by The Company of Biologists Ltd.

  1. Ten-year responses of ground-dwelling spiders to retention harvest in the boreal forest.

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    Pinzon, Jaime; Spence, John R; Langor, David W; Shorthouse, David P

    2016-12-01

    The Ecosystem Management Emulating Natural Disturbances (EMEND) project tests the hypothesis that varying levels of green tree retention maintain and retain forest biodiversity better than conventional clear-cutting. We studied epigaeic spiders to assess biodiversity changes 2, 5, and 10 yr following a range of partial retention harvests (clear-cut, 10-75% retention) and unharvested controls in four boreal mixedwood cover types. A total of 56 371 adult spiders representing 220 species was collected using pitfall traps. Lasting effects on forest structure were proportional to harvest intensity. These changes strongly influenced spider richness, abundance, and species composition, as well as assemblage recovery. Distinctive assemblages were associated with disturbance level, especially with partial harvests (≤50% retention), and these were dominated by open-habitat species even 10 yr after harvest. Assemblages were more similar to those of controls in the highest (75%) retention treatment, but significant recovery toward the structure of pre-disturbance assemblages was not detected for any prescription in any cover type. Although early responses to retention harvest suggested positive effects on spider assemblages, these are better explained as lag effects after harvest because assemblages were less similar to those of unharvested controls 5 yr post-harvest, and only minor recovery was observed 10 yr following harvest. Retention of forest biodiversity decreased over time, especially in conifer stands and the lower (10-50%) retention treatments. Overall, retention harvests retained biodiversity and promoted landscape heterogeneity somewhat better than clear-cutting; however, there was a clear gradient of response and no retention "threshold" for conservation can be recommended on the basis of our data. Furthermore, results suggest that retention harvest prescriptions should be adjusted for cover type. We show that low retention ameliorated impacts in broadleaved

  2. Spider phylogenomics: untangling the Spider Tree of Life

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    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

  3. Spider phylogenomics: untangling the Spider Tree of Life.

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

    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 monophyly of

  4. Spider community responds to litter complexity: insights from a small-scale experiment in an exotic pine stand

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    Luciana R. Podgaiski

    Full Text Available ABSTRACT Conservation of biodiversity in agroecosystems is an urgent need, and a suitable approach to maximize animal biodiversity and their services is the restoration of habitat heterogeneity. Here we investigated the value of increasing litter complexity in tree plantations of exotic pine for ground spiders. We hypothesized that increasing the litter complexity of these systems, as it would be the case in ecologically designed plantations, would increase spider aggregations. We performed a small-scale litter manipulation experiment within an exotic pine stand in the municipality of Minas do Leão, Rio Grande do Sul, Brazil, and compared spider diversity in simple (only pine needles and complex substrates (with the addition of diverse native broadleaves. We found 1,110 spiders, 19 families and 32 morphospecies. The most abundant families were Linyphiidae, Theridiidae and Salticidade, and the dominant morphospecies were Thymoites sp. 2 and Lygarina sp. Web-building spiders represented 61% of total spider abundance, and 17 species, while hunting spiders, 49% and 15 species. As expected, densities of spider individuals and species from both web-building and hunting spiders were higher in complex litter substrate. Potential preys (Collembola also responded positively to the treatment, and had influence of spider community patterns. Our results suggest that ensuring some degree of plant and litter diversity within pine stands (e.g. understory establishment might foster spider aggregations and possibly help to conserve their diversity at local-scales.

  5. Molecular phylogenetics of the spider family Micropholcommatidae (Arachnida: Araneae) using nuclear rRNA genes (18S and 28S).

    Science.gov (United States)

    Rix, Michael G; Harvey, Mark S; Roberts, J Dale

    2008-03-01

    The spider family Micropholcommatidae is an enigmatic taxon of uncertain limits and uncertain affinities. Various phylogenetic hypotheses have been proposed for the family, but these hypotheses have never been tested with a robust phylogenetic analysis. The existence of similar Australasian and New World taxa, the possibility of morphological convergence associated with extreme 'smallness', and the apparent paucity of synapomorphic morphological characters, have all clouded generic relationships in this group. We used fragments from two nuclear ribosomal RNA genes (18S and 28S) to test the monophyly and phylogenetic position of the Micropholcommatidae. The analyses incorporated 50 ingroup spider species, including 23 micropholcommatid species and representatives from 14 other spider families. Ribosomal RNA secondary structures were inferred for the V3-V5 region of the 18S rRNA gene, and Domain II of the 28S rRNA gene of Hickmania troglodytes [Higgins, E.T., Petterd, W.F., 1883. Description of a new cave-inhabiting spider, together with notes on mammalian remains from a recently discovered cave in the Chudleigh district. Pap. Proc. R. Soc. Tasman. 1882, 191-192]. These secondary structures were used to guide multiple sequence alignments, and determine the position and nature of indels in different taxa. Secondary structure information was also incorporated into a structurally partitioned rRNA analysis in MrBayes Version 3.1.2, using a doublet model of nucleotide substitution. This structurally partitioned rRNA analysis provided a less resolved but more conservative and informative estimate of phylogeny than an otherwise identical, unpartitioned rDNA analysis. With the exception of the Chilean species Teutoniella cekalovici [Platnick, N.I., Forster, R.R., 1986. On Teutoniella, an American genus of the spider family Micropholcommatidae (Araneae, Palpimanoidea). Am. Mus. Novit. 2854, 1-9], the family Micropholcommatidae was found to be monophyletic with three

  6. The influence of fire disturbance on the biotype structure and seasonal dynamics of ground-dwelling spider on Cangshan Mountain, Yunnan Province

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    Yanyan Ma

    2014-03-01

    Full Text Available In order to demonstrate the influence of fire disturbance on the function, structure and seasonal dynamics of ground-dwelling spider assemblages, we chose a burned site and an unburned control site. Both study sites were in broadleaf-conifer mixed forest on Cangshan Mountain, Yunnan Province. The results showed that (1 Zelotes zhui (relative dominance value (DV' =33.03, Pardosa chionophila (DV'=22.53 and Sibianor sp. 1 (DV'=8.75 were obviously dominant at the burned site and that Draconarius sp. 2 (DV'=63.50 was absolutely dominant at the control site; (2 At the burned site, the relative abundance of web-builders was significantly lower than that of hunters (P<0.001, whereas the relative abundance of web-builders was significantly higher than that of hunters at the control site; and (3 As season changed, the dominant group fluctuated significantly at the burned, with the lowest abundance during the part of the summer with the maximum rainfall and during the coldest winter; the spider assemblages were stable at the control site, with agelenids consistently the dominant group. These results indicated that fire disturbance changes the community function and structure of ground-dwelling spiders in mixed broadleaf-conifer forest in Cangshan Mountain, increases the relative abundance of hunters and reduces the stability of ground-dwelling spider assemblages.

  7. Spiders in caves

    Science.gov (United States)

    2017-01-01

    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. PMID:28446696

  8. Evolution of Chemosensory Gene Families in Arthropods: Insight from the First Inclusive Comparative Transcriptome Analysis across Spider Appendages

    Science.gov (United States)

    Vizueta, Joel; Frías-López, Cristina; Macías-Hernández, Nuria; Arnedo, Miquel A.

    2017-01-01

    Unlike hexapods and vertebrates, in chelicerates, knowledge of the specific molecules involved in chemoreception comes exclusively from the comparative analysis of genome sequences. Indeed, the genomes of mites, ticks and spiders contain several genes encoding homologs of some insect membrane receptors and small soluble chemosensory proteins. Here, we conducted for the first time a comprehensive comparative RNA-Seq analysis across different body structures of a chelicerate: the nocturnal wandering hunter spider Dysdera silvatica Schmidt 1981. Specifically, we obtained the complete transcriptome of this species as well as the specific expression profile in the first pair of legs and the palps, which are thought to be the specific olfactory appendages in spiders, and in the remaining legs, which also have hairs that have been morphologically identified as chemosensory. We identified several ionotropic (Ir) and gustatory (Gr) receptor family members exclusively or differentially expressed across transcriptomes, some exhibiting a distinctive pattern in the putative olfactory appendages. Furthermore, these IRs were the only known olfactory receptors identified in such structures. These results, integrated with an extensive phylogenetic analysis across arthropods, uncover a specialization of the chemosensory gene repertoire across the body of D. silvatica and suggest that some IRs likely mediate olfactory signaling in chelicerates. Noticeably, we detected the expression of a gene family distantly related to insect odorant-binding proteins (OBPs), suggesting that this gene family is more ancient than previously believed, as well as the expression of an uncharacterized gene family encoding small globular secreted proteins, which appears to be a good chemosensory gene family candidate. PMID:28028122

  9. Spider Veins

    Science.gov (United States)

    ... How to Choose the Best Skin Care Products Spider Veins Treatment Options Learn more about treatment options ... severe venous disease. What you should know about spider veins The exact cause of spider veins is ...

  10. Resolving the phylogeny of a speciose spider group, the family Linyphiidae (Araneae).

    Science.gov (United States)

    Wang, Fang; Ballesteros, Jesus A; Hormiga, Gustavo; Chesters, Douglas; Zhan, Yongjia; Sun, Ning; Zhu, Chaodong; Chen, Wei; Tu, Lihong

    2015-10-01

    For high-level molecular phylogenies, a comprehensive sampling design is a key factor for not only improving inferential accuracy, but also for maximizing the explanatory power of the resulting phylogeny. Two standing problems in molecular phylogenies are the unstable placements of some deep and long branches, and the phylogenetic relationships shown by robust supported clades conflict with recognized knowledge. Empirical and theoretical studies suggest that increasing taxon sampling is expected to ameliorate, if not resolve, both problems; however, sometimes neither the current taxonomic system nor the established phylogeny can provide sufficient information to guide additional sampling design. We examined the phylogeny of the spider family Linyphiidae, and selected ingroup species based on epigynal morphology, which can be reconstructed in a phylogenetic context. Our analyses resulted in seven robustly supported clades within linyphiids. The placements of four deep and long branches are sensitive to variations in both outgroup and ingroup sampling, suggesting the possibility of long branch attraction artifacts. Results of ancestral state reconstruction indicate that successive state transformations of the epigynal plate are associated with early cladogenetic events in linyphiid diversification. Representatives of different subfamilies were mixed together within well supported clades and examination revealed that their defining characters, as per traditional taxonomy, are homoplastic. Furthermore, our results demonstrated that increasing taxon sampling produced a more informative framework, which in turn helps to study character evolution and interpret the relationships among linyphiid lineages. Additional defining characters are needed to revise the linyphiid taxonomic system based on our phylogenetic hypothesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Recruitment and diversification of an ecdysozoan family of neuropeptide hormones for black widow spider venom expression.

    Science.gov (United States)

    McCowan, Caryn; Garb, Jessica E

    2014-02-25

    Venoms have attracted enormous attention because of their potent physiological effects and dynamic evolution, including the convergent recruitment of homologous genes for venom expression. Here we provide novel evidence for the recruitment of genes from the Crustacean Hyperglycemic Hormone (CHH) and arthropod Ion Transport Peptide (ITP) superfamily for venom expression in black widow spiders. We characterized latrodectin peptides from venom gland cDNAs from the Western black widow spider (Latrodectus hesperus), the brown widow (Latrodectus geometricus) and cupboard spider (Steatoda grossa). Phylogenetic analyses of these sequences with homologs from other spider, scorpion and wasp venom cDNAs, as well as CHH/ITP neuropeptides, show latrodectins as derived members of the CHH/ITP superfamily. These analyses suggest that CHH/ITP homologs are more widespread in spider venoms, and were recruited for venom expression in two additional arthropod lineages. We also found that the latrodectin 2 gene and nearly all CHH/ITP genes include a phase 2 intron in the same position, supporting latrodectin's placement within the CHH/ITP superfamily. Evolutionary analyses of latrodectins suggest episodes of positive selection along some sequence lineages, and positive and purifying selection on specific codons, supporting its functional importance in widow venom. We consider how this improved understanding of latrodectin evolution informs functional hypotheses regarding its role in black widow venom as well as its potential convergent recruitment for venom expression across arthropods.

  12. The first lowland species of the Holarctic alpine ground spider genus Parasyrisca (Araneae, Gnaphosidae from Hungary

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    Csaba Szinetár

    2009-07-01

    Full Text Available The first lowland species of the alpine genus Parasyrisca, Parasyrisca arrabonica Szinetár & Eichardt, sp. n., is described from the sandy grasslands of Hungary. The genus was hitherto known only from Western Europe (Pyrenees and Western Alps and Eastern Europe (Crimea, and although records from Slovenia and Romania were known, these are listed in check-lists in both cases as doubtful since no voucher specimens are available. Thus this species is not only the first representative of Parasyrisca in the Hungarian fauna and in the Pannonian region, but is the first verified record of the genus in Central Europe too. Parasyrisca arrabonica seems to belong to the speciose potanini group (of which this is the first European record and the westernmost occurrence to date, and is especially similar to P. turkenica Ovtsharenko, Platnick & Marusik, 1995 and P. songi Marusik & Fritzén, 2009. Detailed descriptions of the species’ ecological characteristics (habitat, co-occurring species are provided, as its habitat preference is unusual and unique within the genus. This species is quite rare: only eight specimens have been found among 20700 captured spiders. Adult specimens have been collected exclusively in late autumn and early spring (so practically outside the major collecting period, which might explain why this species was not discovered earlier.

  13. The Spider's Web: Creativity and Survival in Dynamic Balance.

    Science.gov (United States)

    Cohen, Bill

    2001-01-01

    The spider's web is presented as a model for Indigenous education and community transformation, grounded in Okanagan philosophy. Children are at the center and benefit from the influence of extended family and community. The model's relevance for language revitalization, cultural maintenance, and educational planning and assessment is discussed.…

  14. Bat predation by spiders.

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    Martin Nyffeler

    Full Text Available 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.

  15. 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.

  16. Bites by Australian mygalomorph spiders (Araneae, Mygalomorphae), including funnel-web spiders (Atracinae) and mouse spiders (Actinopodidae: Missulena spp).

    Science.gov (United States)

    Isbister, Geoffrey K; Gray, Mike R

    2004-02-01

    A number of mygalomorph spiders cause bites in Australia, including the funnel-web spiders (Hexathelidae, Atracinae: Hadronyche and Atrax) and mouse spiders (Actinopodidae: Missulena). There is ongoing debate about the significance of bites by mouse spiders and the frequency of severe envenoming by funnel-web spiders. We conducted a prospective cohort study of definite spider bites with expert spider identification and include the analysis of mygalomorph spiders here. Subjects were recruited prospectively from February 1999 to April 2003 from patients presenting to participating hospitals or contacting a state poison information centre. Forty-nine cases of bites by mygalomorph spiders were included: 16 were by funnel-web spiders, 13 by mouse spiders and 20 by other trapdoor spiders (Families Idiopidae and Nemesiidae). Of the 49 bites, 45 (92%) occurred on distal limbs (hands and feet). Local effects included severe pain (53%), puncture marks (61%) and bleeding (27%), local redness (33%). Itchiness did not occur. The following were highly statistically associated with mygalomorph spider bites compared to all other spiders (pweb spider bites, there were 10 cases with minor local effects, four with moderate envenoming (non-specific systemic or local neurotoxicity) and two with severe envenoming requiring antivenom. In addition to local effects, mouse spider bites caused local paraesthesia in three cases, local diaphoresis in one case and non-specific systemic effects in five cases, but not severe envenoming. True trapdoor spider bites caused only minor effects. The data from a mixed species sample of funnel-web spiders confirms previous observations suggesting that only a small proportion of funnel-web bites cause severe effects. Mouse spider bites are unlikely to cause major envenoming but the clinical effects are consistent with neurotoxic venom and are more severe than the trapdoor spiders.

  17. Venom components from Citharischius crawshayi spider (Family Theraphosidae): exploring transcriptome, venomics, and function.

    Science.gov (United States)

    Diego-García, Elia; Peigneur, Steve; Waelkens, Etienne; Debaveye, Sarah; Tytgat, Jan

    2010-08-01

    Despite strong efforts, knowledge about the composition of the venom of many spider species remains very limited. This work is the first report of transcriptome and venom analysis of the African spider Citharischius crawshayi. We used combined protocols of transcriptomics, venomics, and biological assays to characterize the venom and genes expressed in venom glands. A cDNA library of the venom glands was constructed and used to generate expressed sequence tags (ESTs). Sequence comparisons from 236 ESTs revealed interesting and unique sequences, corresponding to toxin-like and other components. Mass spectrometrical analysis of venom fractions showed more than 600 molecular masses, some of which showed toxic activity on crickets and modulated sodium currents in DmNa(v)1 and Na(v)1.6 channels as expressed in Xenopus oocytes. Taken together, our results may contribute to a better understanding of the cellular processes involved in the transcriptome and help us to discover new components from spider venom glands with therapeutic potential.

  18. 辽宁清原山区3种林型地表蜘蛛多样性比较研究%Biodiversity of ground-dwelling spiders in three forest types in Qingyuan Mountain Area, Liaoning

    Institute of Scientific and Technical Information of China (English)

    佟艳丰; 赵丽; 刘悦

    2013-01-01

    2008年5月,采用陷阱法在辽宁省清原县大苏河乡大湖生态站选取杂木林、红松林和落叶松林3种森林植被类型收集地表蜘蛛.共采集成熟蜘蛛标本1 825头,隶属于13科49种.调查发现:1)皿蛛科、漏斗蛛科及平腹蛛科是该地区的优势科,旋卷隙蛛Alloclubionoides circinalis 及皿蛛科一未定种为该地区的优势种;2)3种森林植被类型的地表蜘蛛群落组成存在明显的差异,杂木林中物种最丰富,分布有13科39种,红松林中分布有10科29种,而落叶松林中有8科28种;平腹蛛科在杂木林中最丰富,而在红松林、落叶松林中数量稀少;3)多样性指数存在一定差异,杂木林中个体数量最多,红松林中个体数量最少,Margalef指数及Menhinick指数最低值均出现在红松林,而最高值出现在落叶松林.%In May 2008, the composition and distribution of ground-dwelling spiders were investigated using pitfall trapped method to assess the impact of forest type on spider diversity. Three forest types, i. e. , miscellaneous wood forest, broad-leaved Korean pine forest and deciduous Korean Pine forest were surveyed in Dahu Ecological Station in Dasuhe Town, Qingyuan County, Liaoning Province. A total of 1825 adult individuals were collected, belonging to 13 families and 49 species. The results showed: 1) Linyphiidae, Agelenidae and Gnaphosidae were dominant families, Alloclubionoid.es circinalis and one unidentified species of Linyphiidae were the dominant species; 2) the ground spider community composition were significantly different in the three forest types, 13 families and 39 species were collected from miscellaneous wood forest, 10 families and 29 species were collected from broad-leaved Korean pine forest and 8 families and 28 species were from deciduous Korean Pine forest; gnaphosid spiders were most abundant in miscellaneous wood forest, but sparse in the other two forest types; 3) the diversity indices were also different; the

  19. 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. This article is for information only. DO ...

  20. Venomous Spiders

    Science.gov (United States)

    ... Publications and Products Programs Contact NIOSH NIOSH VENOMOUS SPIDERS Recommend on Facebook Tweet Share Compartir Photo courtesy of University of Missouri Venomous spiders found in the United States include the black ...

  1. The spider family Micropholcommatidae (Arachnida: Araneae: Araneoidea: a relimitation and revision at the generic level

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    Michael Rix

    2010-02-01

    Full Text Available The araneoid spider family Micropholcommatidae Hickman, previously containing 34 southern-temperate species in eight genera, is relimited and revised at the generic level to include 18 genera from Australia, Lord Howe Island, New Caledonia, New Zealand, Papua New Guinea and Chile. Three subfamilies are proposed, and a new phylogenetic hypothesis for the family is presented as a result of two morphological cladistic analyses, used to test the phylogenetic position and phylogeny of the known micropholcommatid taxa. These cladistic analyses inferred a monophyletic Micropholcommatidae, belonging to the diverse araneoid symphytognathidan lineage, with the families Anapidae, Symphytognathidae and Micropholcommatidae further united by the newly proposed 'EbCY' clade. The genus Teutoniella Brignoli, previously included in the Micropholcommatidae, was found to be most closely related to an undescribed genus from South Africa, together forming a distinctive ‘teutoniellid’ lineage within the EbCY clade. The subfamily Micropholcommatinae Hickman, new rank contains the bulk of micropholcommatid diversity, with three tribes, 15 genera and 45 described species. The micropholcommatine tribe Micropholcommatini Hickman, new rank includes the nominate genus Micropholcomma Crosby & Bishop, along with three additional genera from Australasia and Chile: Micropholcomma has eight species, including the type, M. caeligenum Crosby & Bishop, and M. junee sp. n.; Pua Forster is monotypic, with P. novaezealandiae Forster; Tricellina Forster & Platnick is also monotypic, with T. gertschi (Forster & Platnick; and Austropholcomma gen. n. has two species, including the type A. florentine sp. n., and A. walpole sp. n. The micropholcommatine tribe Textricellini Hickman, new rank is a diverse and distinctive lineage, including all species previously described in the genus Textricella Hickman, which is hereby recognised as a junior generic synonym of Eterosonycha Butler syn. n

  2. A check list of the spiders of the Kruger National Park, South Africa (Arachnida: Araneae

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    A.S. Dippenaar-Schoeman

    2003-12-01

    Full Text Available As part of the South African National Survey of Arachnida (SANSA, projects are underway to determine the biodiversity of arachnids present in protected areas in South Africa. Spiders have been collected over a period of 16 years from the Kruger National Park, South Africa. A check list is provided consisting of 152 species, 116 genera and 40 families. This represents about 7.6 % of the total known South African spider fauna. Of the 152 species, 103 are new records for the park. The ground dwelling spiders comprise 58 species from 25 families. Of these, 21 % are web dwellers and 62 % free living, while 17 % live in burrows. From the plant layer, 94 species have been collected of which 53 % were web builders and 47 % free living wandering spiders.

  3. Global patterns of guild composition and functional diversity of spiders.

    Science.gov (United States)

    Cardoso, Pedro; Pekár, Stano; Jocqué, Rudy; Coddington, Jonathan A

    2011-01-01

    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 influenced by

  4. 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

  5. Gone with the plate: the opening of the Western Mediterranean basin drove the diversification of ground-dweller spiders

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    Bidegaray-Batista Leticia

    2011-10-01

    Full Text Available Abstract Background The major islands of the Western Mediterranean--Corsica, Sardinia, and the Balearic Islands--are continental terrenes that drifted towards their present day location following a retreat from their original position on the eastern Iberian Peninsula about 30 million years ago. Several studies have taken advantage of this well-dated geological scenario to calibrate molecular rates in species for which distributions seemed to match this tectonic event. Nevertheless, the use of external calibration points has revealed that most of the present-day fauna on these islands post-dated the opening of the western Mediterranean basin. In this study, we use sequence information of the cox1, nad1, 16S, L1, and 12S mitochondrial genes and the 18S, 28S, and h3 nuclear genes, along with relaxed clock models and a combination of biogeographic and fossil external calibration points, to test alternative historical scenarios of the evolutionary history of the ground-dweller spider genus Parachtes (Dysderidae, which is endemic to the region. Results We analyse 49 specimens representing populations of most Parachtes species and close relatives. Our results reveal that both the sequence of species formation in Parachtes and the estimated divergence times match the geochronological sequence of separation of the main islands, suggesting that the diversification of the group was driven by Tertiary plate tectonics. In addition, the confirmation that Parachtes diversification matches well-dated geological events provides a model framework to infer substitution rates of molecular markers. Divergence rates estimates ranged from 3.5% My-1 (nad1 to 0.12% My-1 (28S, and the average divergence rate for the mitochondrial genes was 2.25% My-1, very close to the "standard" arthropod mitochondrial rate (2.3% My-1. Conclusions Our study provides the first unequivocal evidence of terrestrial endemic fauna of the major western Mediterranean islands, whose origin can

  6. Response of ground-dwelling spider assemblages to prescribed fire following stand structure manipulation in the southern Cascade Range

    Science.gov (United States)

    Nancy E. Gillette; Richard S. Vetter; Sylvia R. Mori; Carline R. Rudolph; Dessa R. Welty

    2008-01-01

    We assessed spider (Arachnida: Araneae) responses to prescribed fire following stand s tructure treatments in ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) stands in the Cascade Range of California. Stands were logged or left untreated to create three levels of structural diversity. We logged one treatment to minimize old-growth...

  7. The influence of vegetation structure on spider species richness, diversity and community organization in the Apšuciems calcareous fen, Latvia

    Energy Technology Data Exchange (ETDEWEB)

    Štokmane, M.; Spuņģis, V.

    2016-07-01

    Calcareous fens are considered to be among the most threatened ecosystems of Europe. They are also one of the most diverse habitats as they support an incredibly rich and diverse range of plant and animal species. However, in spite of their diversity, calcareous fens are still poorly investigated, especially when referring to fen invertebrates, such as spiders. Because spiders are good bioindicators, knowledge of their ecology in rare and threatened habitats is of interest. The aim of this study was to document the composition and diversity of spider species, families and foraging guilds in the ground– and grass–layers of the Apšuciems calcareous fen, and to evaluate the influence of vegetation structure on spider community organization. In summer 2012, we collected ground–dwelling spiders using pitfall traps and grass–dwelling spiders using sweep–netting. A total of 2,937 spider individuals belonging to 19 families and 80 species was collected in the Apšuciems fen. Our results indicate that spider species and families tend to be stratified across the vertical structure of the habitat; the spider composition in the ground stratum differed from that in the grass stratum. On the contrary, however, the spider foraging guild structure between the ground–layer and the grass–layer was similar. Each of the two studied strata presented similar guilds in similar proportions. Our results also showed that spider composition differed considerably between fen parts and that much of this variability could be explained by the architectural properties of the habitat. More diverse vegetation generally supported a higher number of spider species. (Author)

  8. The influence of vegetation structure on spider species richness, diversity and community organization in the Apšuciems calcareous fen, Latvia

    Directory of Open Access Journals (Sweden)

    Štokmane, M.

    2016-07-01

    Full Text Available Calcareous fens are considered to be among the most threatened ecosystems of Europe. They are also one of the most diverse habitats as they support an incredibly rich and diverse range of plant and animal species. However, in spite of their diversity, calcareous fens are still poorly investigated, especially when referring to fen invertebrates, such as spiders. Because spiders are good bioindicators, knowledge of their ecology in rare and threatened habitats is of interest. The aim of this study was to document the composition and diversity of spider species, families and foraging guilds in the ground– and grass–layers of the Apšuciems calcareous fen, and to evaluate the influence of vegetation structure on spider community organization. In summer 2012, we collected ground–dwelling spiders using pitfall traps and grass–dwelling spiders using sweep–netting. A total of 2,937 spider individuals belonging to 19 families and 80 species was collected in the Apšuciems fen. Our results indicate that spider species and families tend to be stratified across the vertical structure of the habitat; the spider composition in the ground stratum differed from that in the grass stratum. On the contrary, however, the spider foraging guild structure between the ground–layer and the grass–layer was similar. Each of the two studied strata presented similar guilds in similar proportions. Our results also showed that spider composition differed considerably between fen parts and that much of this variability could be explained by the architectural properties of the habitat. More diverse vegetation generally supported a higher number of spider species.

  9. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

    Science.gov (United States)

    Chips, Michael J.; Carson, Walter P.

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7–12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread. PMID:27703868

  10. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure.

    Science.gov (United States)

    Roberson, Elizabeth J; Chips, Michael J; Carson, Walter P; Rooney, Thomas P

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

  11. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Roberson

    2016-09-01

    Full Text Available Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7–12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

  12. Spider bite.

    Science.gov (United States)

    Isbister, Geoffrey K; Fan, Hui Wen

    2011-12-10

    Spiders are a source of intrigue and fear, and several myths exist about their medical effects. Many people believe that bites from various spider species cause necrotic ulceration, despite evidence that most suspected cases of necrotic arachnidism are caused by something other than a spider bite. Latrodectism and loxoscelism are the most important clinical syndromes resulting from spider bite. Latrodectism results from bites by widow spiders (Latrodectus spp) and causes local, regional, or generalised pain associated with non-specific symptoms and autonomic effects. Loxoscelism is caused by Loxosceles spp, and the cutaneous form manifests as pain and erythema that can develop into a necrotic ulcer. Systemic loxoscelism is characterised by intravascular haemolysis and renal failure on occasion. Other important spiders include the Australian funnel-web spider (Atrax spp and Hadronyche spp) and the armed spider (Phoneutria spp) from Brazil. Antivenoms are an important treatment for spider envenomation but have been less successful than have those for snake envenomation, with concerns about their effectiveness for both latrodectism and loxoscelism. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Molecular cloning, heterologous expression and functional characterization of a novel translationally-controlled tumor protein (TCTP) family member from Loxosceles intermedia (brown spider) venom.

    Science.gov (United States)

    Sade, Youssef B; Bóia-Ferreira, Marianna; Gremski, Luiza H; da Silveira, Rafael B; Gremski, Waldemiro; Senff-Ribeiro, Andrea; Chaim, Olga M; Veiga, Silvio S

    2012-01-01

    Envenoming with brown spiders (Loxosceles genus) is common throughout the world. Cutaneous symptoms following spider bite accidents include dermonecrosis, erythema, itching and pain. In some cases, accidents can cause hypersensibility or even allergic reactions. These responses could be associated with histaminergic events, such as an increase in vascular permeability and vasodilatation. A protein that may be related to the effects of spider venom was identified from a previously obtained cDNA library of the L. intermedia venom gland. The amino acid sequence of this protein is homologous to proteins from the TCTP (translationally-controlled tumor protein) family, which are extracellular histamine-releasing factors (HRF) that are associated with the allergic reactions to parasites. Herein, we described the cloning, heterologous expression, purification and functional characterization of a novel member of the TCTP family from the Loxosceles intermedia venom gland. This recombinant protein, named LiRecTCTP, causes edema, enhances vascular permeability and is likely related to the inflammatory activity of the venom. Moreover, LiRecTCTP presents an immunological relationship with mammalian TCTPs.

  14. 蒙新区平腹蛛科蜘蛛区系分析%Fauna Analysis of Spiders of the Family Gnaphosidae in Mengxin Area(Arachnida: Araneae)

    Institute of Scientific and Technical Information of China (English)

    范玉香; 唐贵明

    2011-01-01

    分析了蒙新区94种平腹蛛科蜘蛛在世界、中国以及蒙新区动物区系中的分布情况和分布特征.结果表明,在世界动物区系中古北界占明显优势,在中国动物区系中蒙新区与华北区、青藏区以及西南区的共有种较多,蒙新区以东部草原亚区的区系分布为主.%The distribution and the distributive characteristics in Mengxin Area,China,and the world fauna of 94 spider species of the family Gnaphosidae in Mengxin area were elaborately analyzed. The result revealed that the Palaearctic element was dominated obviously in the world spider fauna. Many common species exist in Mengxin area and Northern China,Qingzang area,Southwest area. The Gnaphosidae spiders in Mengxin area are mainly in east plain subregion.

  15. Fauna de arañas del suelo de una comunidad árida-tropical en Baja California Sur, México Ground surface spider fauna in an arid tropical community in Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    María Luisa Jiménez

    2010-08-01

    Full Text Available Se describe la temporalidad y diversidad de arañas del suelo del matorral sarcocaule en la región del Cabo en Baja California Sur. Durante 1991-1992 se realizaron colectas semanales por medio de trampas de caída. Se capturaron 4 322 ejemplares de 53 especies. Las familias con mayor abundancia fueron Miturgidae (42.2%, Oonopidae (23.5%, Caponiidae (8.0% y Gnaphosidae (7.9%. Las especies más abundantes fueron Syspira tigrina Chamberlin (37.1%; Oonops nov. sp. (13.7%, Scaphiella hespera Chamberlin (7.8% y Tarsonops sternalis Chamberlin (5.2%, que constituyeron el 63.7% del total de individuos. Gnaphosidae fue la más rica en especies (11, seguida por Salticidae (7. La riqueza de especies fue constante durante todo el año, con un ligero ascenso en el verano (29 y una ligera disminución en el invierno (24. La diversidad por estación del año se mantuvo en un intervalo de H'= 3.3 -3.7. La abundancia relativa se incrementó en primavera y otoño. La mayor riqueza específica se encontró en otoño. La abundancia relativa y la diversidad de arañas se pueden considerar altas, a pesar del fuerte dominio de la familia Miturgidae. En la mayoría de las especies, la distribución mostró una marcada estacionalidad.Seasonal distribution, specific richness, and diversity of xeric shrub ground spiders were studied at a site in the Cape Region. Weekly collections of spiders were made in 1991-1992 using pit-fall traps. We captured 4 322 specimens in 53 families. Families with the highest number of individuals were: Miturgidae (42% Oonopidae (23.5%, Caponiidae (8.0%, and Gnaphosidae (7.9%. The most abundant species were Syspira tigrina Chamberlin (37.1%; Oonops nov. sp. (13.7%, Scaphiella hespera Chamberlin (7.8%, and Tarsonops sternalis Chamberlin (5.2%, representing 63.7% of the total specimens captured. Gnaphosidae was the richest in species (11 followed by Salticidae (7. Species richness was nearly constant during all the year, with a small increase in

  16. Tubuliform silk protein: A protein with unique molecular characteristics and mechanical properties in the spider silk fibroin family

    Science.gov (United States)

    Tian, M.; Lewis, R. V.

    2006-02-01

    Orb-web weavers can produce up to six different types of silk and a glue for various functions. Tubuliform silk is unique among them due to its distinct amino acid composition, specific time of production, and atypical mechanical properties. To study the protein composing this silk, tubuliform gland cDNA libraries were constructed from three orb-weaving spiders Argiope aurantia, Araneus gemmoides, and Nephila clavipes. Amino acid composition comparison between the predicted tubuliform silk protein sequence (TuSp1) and the corresponding gland protein confirms that TuSp1 is the major component in tubuliform gland in three spiders. Sequence analysis suggests that TuSp1 shares no significant similarity with its paralogues, while it has conserved sequence motifs with the most primitive spider, Euagrus chisoseus silk protein. The presence of large side-chain amino acids in TuSp1 sequence is consistent with the frustrated β-sheet crystalline structure of tubuliform silk observed in transmission electron microscopy. Repeat unit comparison within species as well as among three spiders exhibits high sequence conservation. Parsimony analysis based on carboxy terminal sequence shows that Argiope and Araneus are more closely related than either is to Nephila which is consistent with phylogenetic analysis based on morphological evidence.

  17. Astacin-like metalloproteases are a gene family of toxins present in the venom of different species of the brown spider (genus Loxosceles).

    Science.gov (United States)

    Trevisan-Silva, Dilza; Gremski, Luiza H; Chaim, Olga M; da Silveira, Rafael B; Meissner, Gabriel O; Mangili, Oldemir C; Barbaro, Katia C; Gremski, Waldemiro; Veiga, Silvio S; Senff-Ribeiro, Andrea

    2010-01-01

    Brown spiders have a worldwide distribution, and their venom has a complex composition containing many different molecules. Herein, we report the existence of a family of astacin-like metalloprotease toxins in Loxosceles intermedia venom, as well as in the venom of different species of Loxosceles. Using a cDNA library from the L. intermedia venom gland, we cloned two novel cDNAs encoding astacin-like metalloprotease toxins, LALP2 and LALP3. Using an anti-serum against the previously described astacin-like toxin in L. intermedia venom (LALP1), we detected the presence of immunologically-related toxins in the venoms of L. intermedia, Loxosceles laeta, and Loxosceles gaucho. Zymographic experiments showed gelatinolytic activity of crude venoms of L. intermedia, L. laeta, and L. gaucho (which could be inhibited by the divalent metal chelator 1,10-phenanthroline) at electrophoretic mobilities identical to those reported for immunological cross-reactivity. Moreover, mRNAs extracted from L. laeta and L. gaucho venom glands were screened for astacin-like metalloproteases, and cDNAs obtained using LALP1-specific primers were sequenced, and their deduced amino acid sequences confirmed they were members of the astacin family with the family signatures (HEXXHXXGXXHE and MXY), LALP4 and LALP5, respectively. Sequence comparison of deduced amino acid sequences revealed that LALP2, LALP3, LALP4, and LALP5 are related to the astacin family. This study identified the existence of gene family of astacin-like toxins in the venoms of brown spiders and raises the possibility that these molecules are involved in the deleterious effects triggered by the venom.

  18. SPIDER SILK

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    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.

  19. Spiders (Arachnida: Araneae of Gujarat University Campus, Ahmedabad, India with additional description of Eilica tikaderi (Platnick, 1976

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    Dhruv A. Prajapati

    2016-09-01

    Full Text Available We report a checklist of spiders based on a survey made from August 2013 to July 2014 in Gujarat University Campus, an urban area located in the middle of Ahmadabad City, Gujarat State. A total of 77 species of spiders belonging to 53 genera and 20 families of spiders were recorded from the study area represented by 31.74% of the total 63 families reported from India. Salticidae was found to be the most dominant family with 18 species from 14 genera. Guild structure analysis revealed six feeding guilds, namely stalkers, orb-web builders, space-web builders, ambushers, foliage hunters and ground runners. Stalkers and orb-web builders were the most dominant feeding guilds representing 28.58% and 20.78% respectively among all studied guilds. Species Eilica tikaderi (Platnick, 1976 is reported for the first time from Gujarat with additional description and detailed genitalic illustrations.

  20. 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.

  1. 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.

  2. 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 ...

  3. Spider Bites (For Parents)

    Science.gov (United States)

    ... TV, Video Games, and the Internet 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 ...

  4. Spider silk gut: Development and characterization of a novel strong spider silk fiber

    Science.gov (United States)

    Jiang, Ping; Marí-Buyé, Núria; Madurga, Rodrigo; Arroyo-Hernández, María; Solanas, Concepción; Gañán, Alfonso; Daza, Rafael; Plaza, Gustavo R.; Guinea, Gustavo V.; Elices, Manuel; Cenis, José Luis; Pérez-Rigueiro, José

    2014-12-01

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much larger cross-sectional area of the former. In particular spider silk gut has a proper ground state to which the material can revert independently from its previous loading history by supercontraction. A larger cross-sectional area implies that spider silk gut outperforms the natural material in terms of the loads that the fiber can sustain. This property suggests that it could substitute conventional spider silk fibers in some intended uses, such as sutures and scaffolds in tissue engineering.

  5. Spider silk gut: development and characterization of a novel strong spider silk fiber.

    Science.gov (United States)

    Jiang, Ping; Marí-Buyé, Núria; Madurga, Rodrigo; Arroyo-Hernández, María; Solanas, Concepción; Gañán, Alfonso; Daza, Rafael; Plaza, Gustavo R; Guinea, Gustavo V; Elices, Manuel; Cenis, José Luis; Pérez-Rigueiro, José

    2014-12-05

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much larger cross-sectional area of the former. In particular spider silk gut has a proper ground state to which the material can revert independently from its previous loading history by supercontraction. A larger cross-sectional area implies that spider silk gut outperforms the natural material in terms of the loads that the fiber can sustain. This property suggests that it could substitute conventional spider silk fibers in some intended uses, such as sutures and scaffolds in tissue engineering.

  6. 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.

  7. Diversity and distribution of spiders from Gibbon Wildlife Sanctuary, Assam, India

    Directory of Open Access Journals (Sweden)

    Dilip Kumar Kalita

    2012-07-01

    Full Text Available The study describes the identification of the spider assemblages with respect to their diversity and distribution in the semi evergreen forest, Gibbon Wildlife Sanctuary, Assam, India. The paper aims to introduce this neglected Order- Araneae which is primarily unknown to Science particularly in Northeast India. A total of 95 species of spiders belonging to 56 genera and 18 families were recorded during the study from June-August and October-December, 2011. The species were identified using keys for Indian spiders from (Tikader, 1987; Platnick , 2011. Methodology included active searching at all layers from ground level to tree canopy layer accessible easily for hand collecting and visual surveys. This is the first attempt to report the spider assemblages and their microhabitat preferences from Assam, India. Such surveys are vital for conservation of these creatures and building a biodiversity database of this mega diverse group from a fragmented semi-evergreen forest ecosystem in Assam, India. This study is focused on the neglected diversity of spider fauna representing this semi evergreen forest.

  8. Spider Webs and Silks.

    Science.gov (United States)

    Vollrath, Fritz

    1992-01-01

    Compares the attributes of the silk from spiders with those of the commercially harvested silk from silkworms. Discusses the evolution, design, and effectiveness of spider webs; the functional mechanics of the varieties of silk that can be produced by the same spider; and the composite, as well as molecular, structure of spider silk thread. (JJK)

  9. Spider Webs and Silks.

    Science.gov (United States)

    Vollrath, Fritz

    1992-01-01

    Compares the attributes of the silk from spiders with those of the commercially harvested silk from silkworms. Discusses the evolution, design, and effectiveness of spider webs; the functional mechanics of the varieties of silk that can be produced by the same spider; and the composite, as well as molecular, structure of spider silk thread. (JJK)

  10. Short-term response of soil spiders to cover-crop removal in an organic olive orchard in a Mediterranean setting.

    Science.gov (United States)

    Cárdenas, Manuel; Castro, Juan; Campos, Mercedes

    2012-01-01

    This study shows that disturbance caused by cover-crop removal (CCR) in an organic olive orchard affects ground-spider populations. The effect of CCR on various organic olive-orchard plots was assessed by monitoring the abundance and diversity of ground-dwelling spiders. Covered plots in the organic olive orchard were compared with uncovered plots where the covers had been removed mechanically. CCR positively affected the most abundant spider species Zodarion styliferum (Simon) (Araneae: Zodariidae) as well as other species of running spiders belonging to the families Gnaphosidae and Lycosidae. Over time, the two types of plots did not significantly differ in diversity or dominance. Similarly, no differences were detected between the study plots in terms of the distribution of individuals when a cluster-similarity analysis was performed. This lack of difference in diversity might be due to the spatial scale used in the study or climatology. Because of their general effects, CCR profoundly changed the abundance of spiders in the olive orchard, but with no clear impact on spider diversity.

  11. Short-Term Response of Soil Spiders to Cover-Crop Removal in an Organic Olive Orchard in a Mediterranean Setting

    Science.gov (United States)

    Cárdenas, Manuel; Castro, Juan; Campos, Mercedes

    2012-01-01

    This study shows that disturbance caused by cover-crop removal (CCR) in an organic olive orchard affects ground-spider populations. The effect of CCR on various organic olive-orchard plots was assessed by monitoring the abundance and diversity of ground-dwelling spiders. Covered plots in the organic olive orchard were compared with uncovered plots where the covers had been removed mechanically. CCR positively affected the most abundant spider species Zodarion styliferum (Simon) (Araneae: Zodariidae) as well as other species of running spiders belonging to the families Gnaphosidae and Lycosidae. Over time, the two types of plots did not significantly differ in diversity or dominance. Similarly, no differences were detected between the study plots in terms of the distribution of individuals when a cluster-similarity analysis was performed. This lack of difference in diversity might be due to the spatial scale used in the study or climatology. Because of their general effects, CCR profoundly changed the abundance of spiders in the olive orchard, but with no clear impact on spider diversity. PMID:22938154

  12. 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.

  13. Spider Bite in Iran.

    Science.gov (United States)

    Sanaei-Zadeh, Hossein

    2017-07-01

    Some of the world's most dangerous spiders have been certified in some areas of Iran. Spider bites are common in some geographical areas, and are sporadic in some regions. Spider bites can be classified as latrodectism or loxoscelism. If the patient had not seen the spider, the clinical manifestations of latrodectism could be easily mistaken for other types of bite or sting; or an infectious disease, and withdrawal symptoms, and also loxoscelism could be mistaken for cellulitis, various types of skin infection, or even a sting from a Gadim scorpion (Hemiscorpius lepturus). Given the nonspecific presentation of spider bites, one must keep the diagnosis in mind, and question patients, regarding possible exposure to spiders. Physicians recommend becoming familiar with the geographical distribution of Iranian dangerous spiders, clinical manifestations, and management of their bites. The most useful treatment for spider bite is anti-venom administration. Producing spider bite anti-venom in the Razi Vaccine and Serum Research Institute is under investigation.

  14. Grounded Theory as a "Family of Methods": A Genealogical Analysis to Guide Research

    Science.gov (United States)

    Babchuk, Wayne A.

    2011-01-01

    This study traces the evolution of grounded theory from a nuclear to an extended family of methods and considers the implications that decision-making based on informed choices throughout all phases of the research process has for realizing the potential of grounded theory for advancing adult education theory and practice. [This paper was…

  15. The spiders of the Swartberg Nature Reserve in South Africa (Arachnida: Araneae

    Directory of Open Access Journals (Sweden)

    A.S. Dippenaar-Schoeman

    2005-06-01

    Full Text Available The Swartberg Nature Reserve is situated in the Large Swartberg mountain range, in the Oudtshoorn district of the Western Cape Province. Spiders were collected from the reserve over a 10-year period. This is one of the inventory projects of the South African National Survey (SANSA for spiders of the Succulent Karoo Biome. A total of 45 families comprising 136 genera and 186 species were collected, all which are new records for the area. This represents about 9.4 of the total known South African spider fauna. Of the spiders collected 142 species (76.5 were wanderers and 44 (23.5 web dwellers. The plant dwellers comprised 43.3 of the total number of species and the ground dwellers 56.7 . The Gnaphosidae was the most diverse family represented by 33 species, followed by the Salticidae with 23 and Thomisidae with 15. Ten species are possibly new to science and the Filistatidae is a first record for South Africa. An annotated checklist with information on the guilds, habitat preference and web types are provided.

  16. Using Grounded Theory to Understand Resiliency in Pre-Teen Children of High-Conflict Families

    Science.gov (United States)

    Pomrenke, Marlene

    2007-01-01

    Using grounded theory, this study identified factors that contributed to children's ability to utilize their resilient attributes. Children between the ages of 9 and 12 from high-conflict separated or divorced families participated in a study that examined how family and community interactions promote resilient behaviour. Substantive-level theory…

  17. Bird-eating Spiders

    Institute of Scientific and Technical Information of China (English)

    梁小明

    2002-01-01

    Many people are frightened by spiders (蜘蛛). They are especially afraid of large, hairyones. The largest and most frightening of all is thebird-eating spider, which lives in the hot, thickrain forests of northern South America.

  18. 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)

  19. A Modular Approach for a Family of Ground Mobile Robots

    Directory of Open Access Journals (Sweden)

    Giuseppe Quaglia

    2013-07-01

    Full Text Available This paper deals with Epi.q, a family of mobile robots whose main characteristic is a wheel-legged hybrid locomotion. These multi-purpose robots can be successfully exploited for security and surveillance tasks. The document presents state of the art security robotics, the Epi.q mechanical architecture, the concept behind the robot driving unit, three prototypes and the design of a new one.

  20. Descriptions of two new genera of the spider family Caponiidae (Arachnida, Araneae) and an update of Tisentnops and Taintnops from Brazil and Chile

    Science.gov (United States)

    Brescovit, Antonio D.; Sánchez-Ruiz, Alexander

    2016-01-01

    Abstract New members of the spider family Caponiidae from Brazil and Chile are presented. Three new species in previously known genera are described: Taintnops paposo sp. n. from Chile, and the Brazilian Tisentnops mineiro sp. n. and Tisentnops onix sp. n., both belonging to a genus known only from its damaged type. Additionally, two new non–nopine Brazilian genera are proposed: Nasutonops gen. n. including three new species: Nasutonops chapeu sp. n., Nasutonops sincora sp. n. and Nasutonops xaxado sp. n.; and Carajas gen. n., known only from the type species Carajas paraua sp. n. Both new genera have entire, rather than sub-segmented tarsi. Therefore, they are not included in the caponiid subfamily Nopinae. Nasutonops gen. n. is characterized by the presence of a projected clypeal horn, unique among caponiids. Additionally, the first blind caponiids are described: Tisentnops mineiro sp. n. from the state of Minas Gerais and Carajas paraua sp. n. from the state of Pará. Both of these species are found only in caves and completely lack eyes. PMID:27843380

  1. Descriptions of two new genera of the spider family Caponiidae (Arachnida, Araneae and an update of Tisentnops and Taintnops from Brazil and Chile

    Directory of Open Access Journals (Sweden)

    Antonio D. Brescovit

    2016-10-01

    Full Text Available New members of the spider family Caponiidae from Brazil and Chile are presented. Three new species in previously known genera are described: Taintnops paposo sp. n. from Chile, and the Brazilian Tisentnops mineiro sp. n. and Tisentnops onix sp. n., both belonging to a genus known only from its damaged type. Additionally, two new non–nopine Brazilian genera are proposed: Nasutonops gen. n. including three new species: N. chapeu sp. n., N. sincora sp. n. and N. xaxado sp. n.; and Carajas gen. n., known only from the type species C. paraua sp. n. Both new genera have entire, rather than sub-segmented tarsi. Therefore, they are not included in the caponiid subfamily Nopinae. Nasutonops gen. n. is characterized by the presence of a projected clypeal horn, unique among caponiids. Additionally, the first blind caponiids are described: Tisentnops mineiro sp. n. from the state of Minas Gerais and Carajas paraua sp. n. from the state of Pará. Both of these species are found only in caves and completely lack eyes.

  2. 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…

  3. Spider pheromones - a structural perspective.

    Science.gov (United States)

    Schulz, Stefan

    2013-01-01

    Spiders use pheromones for sexual communication, as do other animals such as insects. Nevertheless, knowledge about their chemical structure, function, and biosynthesis is only now being unraveled. Many studies have shown the existence of spider pheromones, but the responsible compounds have been elucidated in only a few cases. This review focuses on a structural approach because we need to know the involved chemistry if we are to understand fully the function of a pheromonal communication system. Pheromones from members of the spider families Pholcidae, Araneidae, Linyphiidae, Agenelidae, and Ctenidae are currently being identified and will be discussed in this review. Some of these compounds belong to compound classes not known from other arthropod pheromones, such as citric acid derivatives or acylated amino acids, whereas others originate from more common fatty acid metabolism. Their putative biosynthesis, their function, and the identification methods used will be discussed. Furthermore, other semiochemicals and the chemistry of apolar surface lipids that potentially might be used by spiders for communication are described briefly.

  4. Envenomation by spiders of the genus Hololena (Araneae: Agelenidae).

    Science.gov (United States)

    Vetter, Richard S

    2012-09-01

    Three verified bites from Hololena spiders (Family Agelenidae) are presented here. Two male victims, each over 100 kg weight (bitten by female spiders), experienced headaches and 4-h episodes of vomiting. A female bite victim (bitten by a male spider) experienced minor reaction. None sought medical attention; symptoms resolved in a few days. Although these incidents were not serious, reactions in the male victims were more dynamic than usual generic spider bites (minor edema, minor erythema). Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. The Spiders of China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Sevaral books about Chinese spider systematics and biology have been published,mostly since the later 1970s and the majority of then are designed as classification guides to the spider fauna of a particular area of China,or focused on a particular group ,for example Fauna of Zhejiang Province ,Araneida and Salticids of China. The newly published book "The Spiders of China",in English,differs from all others by including all 2361 described Chinese spider species and by reviewing literature of over 200 years of work on Chinese spider classification.

  6. Energy well. Ground-source heat in one-family houses; Energiakaivo. Maalaemmoen hyoedyntaeminen pientaloissa

    Energy Technology Data Exchange (ETDEWEB)

    Juvonen, J.; Lapinlampi, T.

    2013-08-15

    This guide deals with the legislation, planning, building, usage and maintenance of ground-source heat systems. The guide gives recommendations and instructions on national level on the permit practices and how to carry out the whole ground-source heat system project. The main focus of the guide is on energy wells for one-family houses. The principle is that an action permit is needed to build a ground-source heat system. On ground water areas a permit according to the water act may also be required. To avoid any problems, the placement of the system needs to be planned precisely. This guide gives a comprehension to the orderer on the issues that need to be considered before ordering, during construction, when the system is running and when giving up the use of the ground-source heat system. (orig.)

  7. Characterization of a novel peptide toxin from Acanthoscurria paulensis spider venom: a distinct cysteine assignment to the HWTX-II family.

    Science.gov (United States)

    Mourão, Caroline B F; Heghinian, Mari D; Barbosa, Eder A; Marí, Frank; Bloch, Carlos; Restano-Cassulini, Rita; Possani, Lourival D; Schwartz, Elisabeth F

    2013-04-01

    Spider venom toxins have raised interest in prospecting new drugs and pesticides. Nevertheless, few studies are conducted with tarantula toxins, especially with species found in Brazil. This study aims to characterize chemically and biologically the first toxin isolated from Acanthoscurria paulensis venom. Ap1a consists of 48 amino acid residues and has a molecular mass of 5457.79 Da. The cloned gene encodes a putative sequence of 23 amino acid residues for the signal peptide and 27 for the pro-peptide. The sequence of the mature peptide is 60-84% identical with those of toxins of the HWTX-II family. Different from the structural pattern proposed for these toxins, the disulfide pairing of Ap1a is of the ICK type motif, which is also shared by the U1-TRTX-Bs1a toxin. Ap1a induced a dose-dependent and reversible paralytic effect in Spodoptera frugiperda caterpillars, with an ED50 of 13.0 ± 4.2 μg/g 8 h after injections. In the Drosophila melanogaster Giant Fiber circuit, Ap1a (1.14-22.82 μg/g) reduces both the amplitude and frequency of responses from GF-TTM and GF-DLM pathways, suggesting an action at the neuromuscular junction, which is mediated by glutamatergic receptors. It is also lethal to mice (1.67 μg/g, intracranial route), inducing effects similar to those reported with intracerebroventricular administration of NMDA. Ap1a (1 μM) does not alter the response induced by acetylcholine on the rhabdomyosarcoma cell preparation and shows no significant effects on hNav1.2, hNav1.4, hNav1.5, and hNav1.6 channels. Because of its unique sequence and cysteine assignment to the HWTX-II family, Ap1a is a significant contribution to the structure-function study of this family of toxins.

  8. 华模蛛科——采自中国的蜘蛛目一新科(蛛形纲,蜘蛛目)%SINOPIMOIDAE, A NEW SPIDER FAMILY FROM CHINA (ARACHNIDA, ARANEAE)

    Institute of Scientific and Technical Information of China (English)

    李枢强; WUNDERLICH J(o)rg

    2008-01-01

    The new spider family Sinopimoidae fam. nov. (Araneae, Araneoidea), with inopimoa bicolor gen. nov. et sp. nov., is described from a tropical rainforest in Southwest China.%记述了采自我国云南西双版纳雨林的1新科,华模蛛科Sinopimoidae fam.nov.,1新属,华模蛛属Sinopimoa gen.nov.,1新种,双色华模蛛Sinopimoa bicolor sp.nov..模式标本保存在中国科学院动物研究所.

  9. Community structure and composition of litter spiders (Arachnida: Araneae and influence of macro-climatic factors on Parque Ecológico Jatobá Centenário, Morrinhos, Goiás, Brazil

    Directory of Open Access Journals (Sweden)

    Renan Castro Santana

    2015-08-01

    Full Text Available Spiders are a diverse group and are considered to be good bioindicators due to their sensitivity to variation in biotic and abiotic factors.  Despite this the taxonomy of the Araneae is poorly known, particularly in the tropical and subtropical regions.  The use of spider guilds can improve our understanding of the dynamics of spider communities, and in this paper we analyse the influence of climatic factors on guilds and species dominance of spiders within the leaf litter layer of a semi-deciduous forest in the tropical savanna Cerrado, Brazil. The study site was Parque Ecológico Jatobá Centenário, a fragment of 90ha, in Morrinhos, Goiás, Brazil.  Spiders were sampled from November 2006 to August 2007 using pitfall traps that remained open for seven days on each of four occasions.  Overall 4139 spiders from 35 families and 118 species were collected. The main families were Salticidae (28%, Linyphiidae (27%, Lycosidae (12% and Theridiidae (11%.  In terms of richness the main families were: Theridiidae, Salticidae, Corinnidae and Araneidae, with 18, 16, 15 and 13 species respectively. The overall Shannon-Wiener (H’ diversity was 3.6. The rainy season showed higher values than the dry season for abundance (2,868 and 1,271 respectively, richness (100 and 71 and diversity (3,296 and 3,237.  The families Theridiidae, Corinnidae and Salticidae presented more species in both dry and wet seasons.  Observed climatic variation (rainfall, humidity and temperature between seasons influenced the community structure of ground-dwelling spiders

  10. 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.

  11. Spiders and harvestmen on tree trunks obtained by three sampling methods

    Directory of Open Access Journals (Sweden)

    Machač, Ondřej

    2016-04-01

    Full Text Available We studied spiders and harvestmen on tree trunks using three sampling methods. In 2013, spider and harvestman research was conducted on the trunks of selected species of deciduous trees (linden, oak, maple in the town of Přerov and a surrounding floodplain forest near the Bečva River in the Czech Republic. Three methods were used to collect arachnids (pitfall traps with a conservation fluid, sticky traps and cardboard pocket traps. Overall, 1862 spiders and 864 harvestmen were trapped, represented by 56 spider species belonging to 15 families and seven harvestman species belonging to one family. The most effective method for collecting spider specimens was a modified pitfall trap method, and in autumn (September to October a cardboard band method. The results suggest a high number of spiders overwintering on the tree bark. The highest species diversity of spiders was found in pitfall traps, evaluated as the most effective method for collecting harvestmen too.

  12. Rounding up the usual suspects: a standard target-gene approach for resolving the interfamilial phylogenetic relationships of ecribellate orb-weaving spiders with a new family-rank classification (Araneae, Araneoidea)

    DEFF Research Database (Denmark)

    Dimitrov, Dimitar; Benevidas, Ligia R.; Arnedo, Miquel A.;

    2017-01-01

    We test the limits of the spider superfamily Araneoidea and reconstruct its interfamilial relationships using standard molecular markers. The taxon sample (363 terminals) comprises for the first time representatives of all araneoid families, including the first molecular data of the family...... Synaphridae. We use the resulting phylogenetic framework to study web evolution in araneoids. Araneoidea is monophyletic and sister to Nicodamoidea rank. n. Orbiculariae are not monophyletic and also include the RTA clade, Oecobiidae and Hersiliidae. Deinopoidea is paraphyletic with respect to a lineage...... holarchaeids but the family remains diphyletic even if Holarchaea is considered an anapid. The orb-web is ancient, having evolved by the early Jurassic; a single origin of the orb with multiple “losses” is implied by our analyses. By the late Jurassic, the orb-web had already been transformed into different...

  13. Spider-man

    Institute of Scientific and Technical Information of China (English)

    路遇

    2002-01-01

    Spider-Man was first introduced in the comic(连环画) Amazing Fantasy #15(August 1962).Peter Parker,a Senior at Midtown High School,receives his powers when bitten by a exhibition(转基因) spider in a science demonstration(展览).This bite endowed(赋予) him with the proportional(相应的) strength and agility(敏捷) of a spider along with a keen “spider sense”.

  14. Spider trait assembly patterns and resilience under fire-induced vegetation change in South Brazilian grasslands.

    Science.gov (United States)

    Podgaiski, Luciana R; Joner, Fernando; Lavorel, Sandra; Moretti, Marco; Ibanez, Sebastien; Mendonça, Milton de S; Pillar, Valério D

    2013-01-01

    Disturbances induce changes on habitat proprieties that may filter organism's functional traits thereby shaping the structure and interactions of many trophic levels. We tested if communities of predators with foraging traits dependent on habitat structure respond to environmental change through cascades affecting the functional traits of plants. We monitored the response of spider and plant communities to fire in South Brazilian Grasslands using pairs of burned and unburned plots. Spiders were determined to the family level and described in feeding behavioral and morphological traits measured on each individual. Life form and morphological traits were recorded for plant species. One month after fire the abundance of vegetation hunters and the mean size of the chelicera increased due to the presence of suitable feeding sites in the regrowing vegetation, but irregular web builders decreased due to the absence of microhabitats and dense foliage into which they build their webs. Six months after fire rosette-form plants with broader leaves increased, creating a favourable habitat for orb web builders which became more abundant, while graminoids and tall plants were reduced, resulting in a decrease of proper shelters and microclimate in soil surface to ground hunters which became less abundant. Hence, fire triggered changes in vegetation structure that lead both to trait-convergence and trait-divergence assembly patterns of spiders along gradients of plant biomass and functional diversity. Spider individuals occurring in more functionally diverse plant communities were more diverse in their traits probably because increased possibility of resource exploitation, following the habitat heterogeneity hypothesis. Finally, as an indication of resilience, after twelve months spider communities did not differ from those of unburned plots. Our findings show that functional traits provide a mechanistic understanding of the response of communities to environmental change

  15. Spider trait assembly patterns and resilience under fire-induced vegetation change in South Brazilian grasslands.

    Directory of Open Access Journals (Sweden)

    Luciana R Podgaiski

    Full Text Available Disturbances induce changes on habitat proprieties that may filter organism's functional traits thereby shaping the structure and interactions of many trophic levels. We tested if communities of predators with foraging traits dependent on habitat structure respond to environmental change through cascades affecting the functional traits of plants. We monitored the response of spider and plant communities to fire in South Brazilian Grasslands using pairs of burned and unburned plots. Spiders were determined to the family level and described in feeding behavioral and morphological traits measured on each individual. Life form and morphological traits were recorded for plant species. One month after fire the abundance of vegetation hunters and the mean size of the chelicera increased due to the presence of suitable feeding sites in the regrowing vegetation, but irregular web builders decreased due to the absence of microhabitats and dense foliage into which they build their webs. Six months after fire rosette-form plants with broader leaves increased, creating a favourable habitat for orb web builders which became more abundant, while graminoids and tall plants were reduced, resulting in a decrease of proper shelters and microclimate in soil surface to ground hunters which became less abundant. Hence, fire triggered changes in vegetation structure that lead both to trait-convergence and trait-divergence assembly patterns of spiders along gradients of plant biomass and functional diversity. Spider individuals occurring in more functionally diverse plant communities were more diverse in their traits probably because increased possibility of resource exploitation, following the habitat heterogeneity hypothesis. Finally, as an indication of resilience, after twelve months spider communities did not differ from those of unburned plots. Our findings show that functional traits provide a mechanistic understanding of the response of communities to

  16. Morphological evolution of spiders predicted by pendulum mechanics.

    Directory of Open Access Journals (Sweden)

    Jordi Moya-Laraño

    Full Text Available BACKGROUND: Animals have been hypothesized to benefit from pendulum mechanics during suspensory locomotion, in which the potential energy of gravity is converted into kinetic energy according to the energy-conservation principle. However, no convincing evidence has been found so far. Demonstrating that morphological evolution follows pendulum mechanics is important from a biomechanical point of view because during suspensory locomotion some morphological traits could be decoupled from gravity, thus allowing independent adaptive morphological evolution of these two traits when compared to animals that move standing on their legs; i.e., as inverted pendulums. If the evolution of body shape matches simple pendulum mechanics, animals that move suspending their bodies should evolve relatively longer legs which must confer high moving capabilities. METHODOLOGY/PRINCIPAL FINDINGS: We tested this hypothesis in spiders, a group of diverse terrestrial generalist predators in which suspensory locomotion has been lost and gained a few times independently during their evolutionary history. In spiders that hang upside-down from their webs, their legs have evolved disproportionately longer relative to their body sizes when compared to spiders that move standing on their legs. In addition, we show how disproportionately longer legs allow spiders to run faster during suspensory locomotion and how these same spiders run at a slower speed on the ground (i.e., as inverted pendulums. Finally, when suspensory spiders are induced to run on the ground, there is a clear trend in which larger suspensory spiders tend to run much more slowly than similar-size spiders that normally move as inverted pendulums (i.e., wandering spiders. CONCLUSIONS/SIGNIFICANCE: Several lines of evidence support the hypothesis that spiders have evolved according to the predictions of pendulum mechanics. These findings have potentially important ecological and evolutionary implications since

  17. Chemical attraction of kleptoparasitic flies to heteropteran insects caught by orb-weaving spiders.

    OpenAIRE

    Eisner, T.; Eisner, M; Deyrup, M

    1991-01-01

    Insects of the heteropteran families Pentatomidae (stink bugs) and Coreidae (squash bugs), when being eaten by the orb-weaving spider Nephila clavipes, attract flies of the family Milichiidae. The flies aggregate on the bugs and, as kleptoparasites, share in the spider's meal. Stink bugs and squash bugs typically eject defensive sprays when attacked; they do so when caught by Nephila, but the spray only minimally affects the spider. Evidence is presented indicating that it is the spray of the...

  18. 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.

  19. Bird predation affects diurnal and nocturnal web-building spiders in a Mediterranean citrus grove

    Science.gov (United States)

    Mestre, L.; Garcia, N.; Barrientos, J. A.; Espadaler, X.; Piñol, J.

    2013-02-01

    Spiders and birds can greatly decrease insect populations, but birds also limit spider densities in some habitats. Bird predation is thought to be one of the causes behind nocturnal activity in spiders, so night-active spiders that hide in retreats during the day should be less affected by bird foraging than day-active spiders. However, this hypothesis has not yet been tested. We investigated the importance of bird predation on the spider community of a Mediterranean organic citrus grove. We excluded birds by placing net cages over the trees and we conducted visual searches in the canopies to sample web-building spiders. As there are many nocturnal species in the family Araneidae, we conducted searches both by day and by night to compare the abundance of active araneids in these two time periods. We sampled the tree trunks with cardboard bands to collect hunting spiders. In bird-excluded canopies there were more spiders of the families Araneidae and Theridiidae. There were higher numbers of active Araneidae at night, but these were just as negatively affected by bird predation as day-active Araneidae, so there was no evidence of nocturnal activity serving as an anti-predator strategy. We did not find any negative impact of birds on hunting spiders. Our results contrast with other studies reporting a negative effect of birds on hunting but not on web-building spiders.

  20. Spiders and Silk

    Institute of Scientific and Technical Information of China (English)

    熊世民

    2004-01-01

    Spiders are very small, so it is easy to think that they do not make anything strong. However, a scientist at Oxford University in Britain has discovered this is not true. David Knight says that eight-legged spiders create a material called silk that could be as strong as rope.

  1. Disgust and spider phobia

    NARCIS (Netherlands)

    Mulkens, SAN; de Jong, Peter; Merckelbach, H

    1996-01-01

    Twenty-four women with spider phobia and 45 nonphobic women completed the Disgust Questionnaire(DQ; P. Rozin, A. E. Fallen, & R. Mandell, 1984) and the Spider Phobia Questionnaire (SPQ; R. Klorman, T. C. Weerts, J. E. Hastings, B. G. Melamed, gr P. J. Lang, 1974). Participants also underwent behavio

  2. 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.

  3. Disgust and spider phobia

    NARCIS (Netherlands)

    Mulkens, SAN; de Jong, Peter; Merckelbach, H

    1996-01-01

    Twenty-four women with spider phobia and 45 nonphobic women completed the Disgust Questionnaire(DQ; P. Rozin, A. E. Fallen, & R. Mandell, 1984) and the Spider Phobia Questionnaire (SPQ; R. Klorman, T. C. Weerts, J. E. Hastings, B. G. Melamed, gr P. J. Lang, 1974). Participants also underwent behavio

  4. Becoming a Spider Scientist

    Science.gov (United States)

    Patrick, Patricia; Getz, Angela

    2008-01-01

    In this integrated unit, third grade students become spider scientists as they observe spiders in their classroom to debunk some common misconceptions about these intimidating creatures. "Charlotte's Web" is used to capture students' interest. In addition to addressing philosophical topics such as growing-up, death, and friendship; E.B. White's…

  5. Tangled in a sparse spider web

    DEFF Research Database (Denmark)

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

    2012-01-01

    orb-weaving families and web designs were already present. The processes that may have given origin to this diversification of lineages and web architectures are discussed. A combination of biotic factors, such as key innovations in web design and silk composition, as well as abiotic environmental......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...

  6. Secondary eyes mediate the response to looming objects in jumping spiders (Phidippus audax, Salticidae).

    Science.gov (United States)

    Spano, Lauren; Long, Skye M; Jakob, Elizabeth M

    2012-12-23

    Some species have sensory systems divided into subsystems with morphologically different sense organs that acquire different types of information within the same modality. Jumping spiders (family Salticidae) have eight eyes. Four eyes are directed anteriorly to view objects in front of the spider: a pair of principal eyes track targets with their movable retinae, while the immobile anterior lateral (AL) eyes have a larger field of view and lower resolution. To test whether the principal eyes, the AL eyes, or both together mediate the response to looming stimuli, we presented spiders with a video of a solid black circle that rapidly expanded (loomed) or contracted (receded). Control spiders and spiders with their principal eyes masked were significantly more likely to back away from the looming stimulus than were spiders with their AL eyes masked. Almost no individuals backed away from the receding stimulus. Our results show that the AL eyes alone mediate the loom response to objects anterior to the spider.

  7. A two year study of verified spider bites in Switzerland and a review of the European spider bite literature.

    Science.gov (United States)

    Nentwig, Wolfgang; Gnädinger, Markus; Fuchs, Joan; Ceschi, Alessandro

    2013-10-01

    During a two-year study, all spider bites recorded by Swiss primary care physicians were reported to the Swiss Toxicological Information Centre and all collected spiders were identified. A total of 14 verified spider bites were recorded, involving five species from four families: Zoropsis spinimana (five cases), Cheiracanthium punctorium (four cases), Tegenaria atrica (three cases) and one case of Malthonica ferruginea (= Tegenaria ferruginea) (both Agelenidae), and one case of Amaurobius ferox (Amaurobiidae). The bites of all spider species produced relatively mild symptoms. Local symptoms such as moderate to severe pain, circumscribed swelling and redness were the only effects in most cases. Systemic symptoms were rare. There was complete recovery in all cases and all lesions healed completely without further damage or secondary disorders. Following a review of the European spider bite literature, the number of spider species capable of biting humans in Europe is considered to be much larger than could be concluded from this study. Most spider bites are restricted to species living synanthropically, thus promoted by climate and habitat change. The annual frequency of spider bites in Switzerland is estimated at 10-100 bites per million inhabitants, but this is predicted to increase due to the continuous arrival of new alien species, many of which have a high potential to establish in urban areas. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. SPIDERS (ARANEI OF VOLGOGRAD SITY AND ITS ENVIRONS

    Directory of Open Access Journals (Sweden)

    A. V. Ponomarev

    2013-01-01

    Full Text Available Abstract. Aim. Fauna of spiders of Volgograd Region is researched uncompletely. Only 149 species of 19 families were listed in previous references. Complete listing of spiders of this large region was the aim of our investigation.Location. Volgograd Region, Russia.Methods. Material was collected in Volgograd City with environs and Volga-Don area in 2009–2013. Areas with minimum of anthropogenic influence within the city, artificial ecosystem of park type, plots of native vegetation along the Varvarovskoe water reservoir and natural steppe on banks of Don River were investigated. The main method of spiders’ collection were pitfall traps, which exposed from April to October.Results and main conclusions. As a result 235 species of spiders from 26 families (including 195 species from 23 families within the city were found. One hundred fifty five species are new for Volgograd Region. Spiders of families Atypidae, Corinnidae, Dysderidae, Eresidae, Liocranidae, Sparassidae, Zodariidae were not found in Volgograd Region earier. Trichoncus villius Tanasevitch et Piterkina, 2007 is the first record for Russia. Totally 304 species of spiders are known from Volgograd Region after our study including literature data. New data about fauna of spiders with summarized check-list are very significant for future faunistic and biogeographic investigations. Study of river islands with minimum anthropogenic influence inside Volgograd City allow to develop measures for biodiversity conservation.

  9. Family, state, class and solidarity: re-conceptualising intergenerational solidarity through the grounded theory approach.

    Science.gov (United States)

    Timonen, Virpi; Conlon, Catherine; Scharf, Thomas; Carney, Gemma

    2013-09-01

    The relationship between class and intergenerational solidarities in the public and private spheres calls for further conceptual and theoretical development. This article discusses the findings from the first wave of a qualitative longitudinal study entitled Changing Generations, conducted in Ireland in 2011-2012, comprising 100 in-depth interviews with men and women across the age and socioeconomic spectrums. Constructivist grounded theory analysis of the data gives rise to the following postulates: (1) intergenerational solidarity at the family level is strongly contoured by socioeconomic status (SES); (2) intergenerational solidarity evolves as family generations observe each others' practices and adjust their expectations accordingly; (3) intergenerational solidarity within families is also shaped by the public sphere (the welfare state) that generates varying expectations and levels of solidarity regarding State supports for different age groups, again largely dependent on SES; (4) the liberal welfare state context, especially at a time of economic crisis, enhances the significance of intergenerational solidarity within families. We conclude by calling for research that is attuned to age/generation, gender and class, and how these operate across the family and societal levels.

  10. Self-made shelters protect spiders from predation

    Science.gov (United States)

    Manicom, Carryn; Schwarzkopf, Lin; Alford, Ross A.; Schoener, Thomas W.

    2008-01-01

    Many animals modify their environments, apparently to reduce predation risk, but the success of such endeavors, and their impact on the density and distribution of populations, are rarely rigorously demonstrated. We staged a manipulative experiment to assess the effectiveness of self-made shelters by web spiders as protection from natural enemies. Scincid lizards were included or excluded from 21 replicated 200-m2 plots, and spiders therein were classified as exposed or sheltered, depending on whether they were uncovered in their web or hidden in cocoons, leaves/debris, or burrows. We found that exposed spiders were greatly affected by the presence of predatory scincid lizards, whereas sheltered spiders were not. More specifically, lizards, which forage close to the ground, reduced the abundance of exposed spiders by two-thirds but had no effect on the abundance of sheltered spiders. Sheltered spiders were able to avoid predation and share space with lizards, suggesting that shelter construction is a mechanism for reducing predation risk and has important population consequences. PMID:18772383

  11. Factors influencing decision-making around family presence during resuscitation: a grounded theory study.

    Science.gov (United States)

    Giles, Tracey; de Lacey, Sheryl; Muir-Cochrane, Eimear

    2016-11-01

    The aim of this study was to examine factors impacting family presence during resuscitation practices in the acute care setting. Family presence during resuscitation was introduced in the 1980s, so family members/significant others could be with their loved ones during life-threatening events. Evidence demonstrates important benefits; yet despite growing support from the public and endorsement from professional groups, family presence is practiced inconsistently and rationales for poor uptake are unclear. Constructivist grounded theory design. Twenty-five health professionals, family members and patients informed the study. In-depth interviews were undertaken between October 2013-November 2014 to interpret and explain their meanings and actions when deciding whether to practice or participate in FPDR. The Social Construction of Conditional Permission explains the social processes at work when deciding to adopt or reject family presence during resuscitation. These processes included claiming ownership, prioritizing preferences and rights, assessing suitability, setting boundaries and protecting others/self. In the absence of formal policies, decision-making was influenced primarily by peoples' values, preferences and pre-existing expectations around societal roles and associated status between health professionals and consumers. As a result, practices were sporadic, inconsistent and often paternalistic rather than collaborative. An increased awareness of the important benefits of family presence and the implementation of clinical protocols are recommended as an important starting point to address current variations and inconsistencies in practice. These measures would ensure future practice is guided by evidence and standards for health consumer safety and welfare rather than personal values and preferences of the individuals 'in charge' of permissions. © 2016 John Wiley & Sons Ltd.

  12. Spiders in random environment

    CERN Document Server

    Gallesco, Christophe; Popov, Serguei; Vachkovskaia, Marina

    2010-01-01

    A spider consists of several, say $N$, particles. Particles can jump independently according to a random walk if the movement does not violate some given restriction rules. If the movement violates a rule it is not carried out. We consider random walk in random environment (RWRE) on $\\Z$ as underlying random walk. We suppose the environment $\\omega=(\\omega_x)_{x \\in \\Z}$ to be elliptic, with positive drift and nestling, so that there exists a unique positive constant $\\kappa$ such that $\\E[((1-\\omega_0)/\\omega_0)^{\\kappa}]=1$. The restriction rules are kept very general; we only assume transitivity and irreducibility of the spider. The main result is that the speed of a spider is positive if $\\kappa/N>1$ and null if $\\kappa/N<1$. In particular, if $\\kappa/N <1$ a spider has null speed but the speed of a (single) RWRE is positive.

  13. Spider webs: Damage control

    Science.gov (United States)

    Omenetto, Fiorenzo G.; Kaplan, David L.

    2012-04-01

    A study reveals that spider orb webs fail in a nonlinear fashion, owing to the hierarchical organization of the silk proteins. The discovery may serve as inspiration for engineers for the design of aerial, light-weight, robust architectures.

  14. Black widow spider (image)

    Science.gov (United States)

    This is a black widow spider. Note the red "hour glass" on the abdomen. The bite of the black widow can produce severe symptoms but is seldom fatal, except in young children and older adults. (Image courtesy ...

  15. Normalization of Neglect: A Grounded Theory of RNs' Experiences as Family Caregivers of Hospitalized Seniors.

    Science.gov (United States)

    Taverner, Tarnia; Baumbusch, Jennifer; Taipale, Priscilla

    2016-06-01

    Often older people, while maintaining a level of independence, rely on family members to provide care and assistance. Caregivers who are also registered nurses (RNs) may provide a different perspective around the experience when their older relative is admitted to acute care. The aim of our research was to investigate and develop theory regarding nursing care provision as described by RNs, who were family caregivers to older adults, when that older adult was admitted to acute care. Over a six-month period in 2011, RNs meeting this criterion (n = 12) were interviewed individually. We identified two central categories: "Culture of Neglect" and "Vigil by the Bedside". The core category "Normalization of Neglect" was identified as the theory, grounded in the data the participants provided which described a culture of neglect that had normalized poor nursing care. These findings highlight the issue of neglect and abuse, and further investigation is warranted.

  16. Molecular phylogeny of Pompilinae (Hymenoptera: Pompilidae): Evidence for rapid diversification and host shifts in spider wasps.

    Science.gov (United States)

    Rodriguez, Juanita; Pitts, James P; Florez, Jaime A; Bond, Jason E; von Dohlen, Carol D

    2016-01-01

    Pompilinae is one of the largest subfamilies of spider wasps (Pompilidae). Most pompilines are generalist spider predators at the family level, but some taxa exhibit ecological specificity (i.e., to spider-host guild). Here we present the first molecular phylogenetic analysis of Pompilinae, toward the aim of evaluating the monophyly of tribes and genera. We further test whether changes in the rate of diversification are associated with host-guild shifts. Molecular data were collected from five nuclear loci (28S, EF1-F2, LWRh, Wg, Pol2) for 76 taxa in 39 genera. Data were analyzed using maximum likelihood (ML) and Bayesian inference (BI). The phylogenetic results were compared with previous hypotheses of subfamilial and tribal classification, as well as generic relationships in the subfamily. The classification of Pompilus and Agenioideus is also discussed. A Bayesian relaxed molecular clock analysis was used to examine divergence times. Diversification rate-shift tests accounted for taxon-sampling bias using ML and BI approaches. Ancestral host family and host guild were reconstructed using MP and ML methods. Ancestral host guild for all Pompilinae, for the ancestor at the node where a diversification rate-shift was detected, and two more nodes back in time was inferred using BI. In the resulting phylogenies, Aporini was the only previously proposed monophyletic tribe. Several genera (e.g., Pompilus, Microphadnus and Schistonyx) are also not monophyletic. Dating analyses produced a well-supported chronogram consistent with topologies from BI and ML results. The BI ancestral host-use reconstruction inferred the use of spiders belonging to the guild "other hunters" (frequenting the ground and vegetation) as the ancestral state for Pompilinae. This guild had the highest probability for the ML reconstruction and was equivocal for the MP reconstruction; various switching events to other guilds occurred throughout the evolution of the group. The diversification of

  17. The experiences of families of critically ill patients in Greece: a social constructionist grounded theory study.

    Science.gov (United States)

    Plakas, Sotirios; Cant, Bob; Taket, Ann

    2009-02-01

    The experiences of patients' families in intensive care units (ICUs) are of international concern. In Greece however, adequate attention has not been paid to this issue. To explore the experiences of critical care patients' families in Greece. The intensive care units of 3 general district hospitals in the area of Athens, Greece. The social constructionist version of grounded theory was used. In-depth interviews with 25 relatives of critically ill patients were carried out, and participant and non-participant observation was used to cross-validate the data obtained. Seven major categories were identified, with 32 components across all categories. The experiences of families revolved around the two core categories of "Intense Emotions" and "Vigilant Attendance". The study conceptualised two new categories in this field, "Religiosity" and "Loss of Intimacy" and enhanced the category "Vigilant Attendance". Three further categories were identified, namely "Caring", "Dignity" and "Information". The various interrelationships between the categories were also examined. The study has examined the experience of Greek patients' families from a qualitative perspective and suggests that major changes need to be made in terms of management and support.

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

    NARCIS (Netherlands)

    Vrijsen, J.N.; Fleurkens, P.F.T.; Nieuwboer, W.; Rinck, M.

    2009-01-01

    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

  19. Attentional and behavioural responses of spider fearfuls to virtual spiders

    NARCIS (Netherlands)

    Rinck, M.; Kwakkenbos, C.M.C.; Dotsch, R.; Wigboldus, D.H.J.; Becker, E.S.

    2009-01-01

    This study employed an immersed virtual environment (IVE) in the Nijmegen RIVERlab to study spider fearfuls' attentional and motor reactions to virtual spiders. The participants were exposed to virtual spiders while completing an unrelated task, walking freely through a virtual museum. Compared to

  20. Spider Silk For Future Scaffolds

    OpenAIRE

    Bringhurst, Heidi; Decker, R.; Frisby, S.; Tucker, C.

    2014-01-01

    Spider silk, an ancient biomaterial, has many qualities worth replicating. With the use of genetic modification, relatively large amounts of the spider silk protein have been produced through goat milk. With access to this protein we have worked to create spider silk films and hydrogels. Through chemical and mechanical means, we are discovering treatments that maximize cell growth and cell attachment on spider silk films and hydrogels.

  1. Myocarditis following katipo spider bite.

    Science.gov (United States)

    Crook, Ruth; Harrison, Nigel; Gibbons, Derek

    2010-05-14

    We report the case of a 22-year-old man who developed severe myocarditis following a presumed katipo spider bite. Katipo spiders are thought to be one of the most poisonous native creatures in New Zealand. No deaths from katipo spider bites have been reported since the 19th Century. A literature search reveals no previously reported cases of myocarditis following a bite from a katipo spider. The clinical presentation of latrodectism is discussed.

  2. Spider Silk For Future Scaffolds

    OpenAIRE

    Bringhurst, Heidi; Decker, R.; Frisby, S.; Tucker, C

    2014-01-01

    Spider silk, an ancient biomaterial, has many qualities worth replicating. With the use of genetic modification, relatively large amounts of the spider silk protein have been produced through goat milk. With access to this protein we have worked to create spider silk films and hydrogels. Through chemical and mechanical means, we are discovering treatments that maximize cell growth and cell attachment on spider silk films and hydrogels.

  3. 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 this ... effects of a bite from the funnel-web spider. Male funnel-web spiders are more poisonous than females. This article ...

  4. 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

  5. Early events in the evolution of spider silk genes.

    Science.gov (United States)

    Starrett, James; Garb, Jessica E; Kuelbs, Amanda; Azubuike, Ugochi O; Hayashi, Cheryl Y

    2012-01-01

    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 compositions of

  6. Australian wolf spider bites (Lycosidae): clinical effects and influence of species on bite circumstances.

    Science.gov (United States)

    Isbister, Geoffrey K; Framenau, Volker W

    2004-01-01

    Necrotic arachnidism continues to be attributed to wolf spider bites. This study investigates the clinical effects of bites by wolf spiders in Australia (family Lycosidae). Subjects were recruited prospectively from February 1999 to April 2001 from participating emergency departments or state poison information centers. Subjects were included if they had a definite bite by a wolf spider and had collected the spider, which was later identified by an arachnologist. Spiders were identified to the lowest taxonomic level possible and cephalothorax width was measured to correlate bite effects and spider size. There were 45 definite wolf spider bites (23 male and 22 female patients; age range 1 to 69 years, median age 28 years). Species level identifications (14 species) were possible for 31 of 43 spiders belonging to seven different generic groupings. Most bites were by spiders from four generic groupings, Tasmanicosa (including 'Lycosa') (15), Venatrix (8), Venator (10), and Hogna (7). Bites occurred more commonly in south-eastern Australia and occurred throughout the year, with 7 bites (16%) in late autumn or winter. In 7 cases (16%) the person was swimming in or cleaning a pool. Seventy-two percent of bites occurred on distal parts of limbs. Pain occurred in all bites and was severe in 11 cases (24%), with a median duration of 10 min (IQR: 2-60 min). Other effects included puncture marks/bleeding (33%), swelling (20%), redness (67%), and itchiness (13%). Minor systemic effects occurred in three patients (7%): nausea (two), headache (one) and malaise (one). There were no cases of necrotic ulcers [0%; 97.5% CI 0-8%]. Tasmanicosa spider bites caused significantly more itchiness and redness, and large spiders (>5 mm) more often caused severe pain and left fang marks. Wolf spider bites cause minor effects, no more severe than most other spiders, and do not appear to cause necrotic ulcers. The effects are likely to be due to mechanical injury, although minor local

  7. A Continuous Family of Equilibria in Ferromagnetic Media are Ground States

    Science.gov (United States)

    Su, Xifeng; de la Llave, Rafael

    2017-09-01

    We show that a foliation of equilibria (a continuous family of equilibria whose graph covers all the configuration space) in ferromagnetic transitive models are ground states. The result we prove is very general, and it applies to models with long range and many-body interactions. As an application, we consider several models of networks of interacting particles including models of Frenkel-Kontorova type on Z^d and one-dimensional quasi-periodic media. The result above is an analogue of several results in the calculus of variations (fields of extremals) and in PDE's. Since the models we consider are discrete and long range, new proofs need to be given. We also note that the main hypothesis of our result (the existence of foliations of equilibria) is the conclusion (using KAM theory) of several recent papers. Hence, we obtain that the KAM solutions recently established are minimizers when the interaction is ferromagnetic and transitive (these concepts are defined later).

  8. 智能搜索蜘蛛%Intelligent Search Spiders

    Institute of Scientific and Technical Information of China (English)

    武海燕; 甘利人

    2001-01-01

    The search mechanism and the search process of the intelligent search spiders developed by the University of Arizona, which include Competitive Intelligence (CI) Spider, Meta Spider and Cancer Spider, are introduced. The characteristics of these spiders are summarized.

  9. Intraguild interactions between spiders and ants and top-down control in a grassland food web.

    Science.gov (United States)

    Sanders, Dirk; Platner, Christian

    2007-01-01

    In most terrestrial ecosystems ants (Formicidae) as eusocial insects and spiders (Araneida) as solitary trappers and hunters are key predators. To study the role of predation by these generalist predators in a dry grassland, we manipulated densities of ants and spiders (natural and low density) in a two-factorial field experiment using fenced plots. The experiment revealed strong intraguild interactions between ants and spiders. Higher densities of ants negatively affected the abundance and biomass of web-building spiders. The density of Linyphiidae was threefold higher in plots without ant colonies. The abundance of Formica cunicularia workers was significantly higher in spider-removal plots. Also, population size of springtails (Collembola) was negatively affected by the presence of wandering spiders. Ants reduced the density of Lepidoptera larvae. In contrast, the abundance of coccids (Ortheziidae) was positively correlated with densities of ants. To gain a better understanding of the position of spiders, ants and other dominant invertebrate groups in the studied food web and important trophic links, we used a stable isotope analysis ((15)N and (13)C). Adult wandering spiders were more enriched in (15)N relative to (14)N than juveniles, indicating a shift to predatory prey groups. Juvenile wandering and web-building spiders showed delta(15)N ratios just one trophic level above those of Collembola, and they had similar delta(13)C values, indicating that Collembola are an important prey group for ground living spiders. The effects of spiders demonstrated in the field experiment support this result. We conclude that the food resource of spiders in our study system is largely based on the detrital food web and that their effects on herbivores are weak. The effects of ants are not clear-cut and include predation as well as mutualism with herbivores. Within this diverse predator guild, intraguild interactions are important structuring forces.

  10. Hey! A Black Widow Spider Bit Me!

    Science.gov (United States)

    ... widow spider, tell an adult immediately . Black widow spider bites rarely kill people, but it's important to get ... a medication that fights the venom in the spider's bite, if someone who has been bitten has underlying ...

  11. 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.

  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.

    Science.gov (United States)

    Matsuda, Tomoko; Morishita, Maiko; Hinomoto, Norihide; Gotoh, Tetsuo

    2014-01-01

    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. Spider bites - Assessment and management.

    Science.gov (United States)

    Braitberg, George; Segal, Leslie

    2009-11-01

    Spider bite is common, but most species cause minimal or no effects. Patients may be misinformed regarding the nature and consequences of a bite. Understanding the current literature can assist the physician in the management of spider bite patients. This article reviews the current literature on spider bites and describes the clinical assessment and management of the medically important spider bites. Most spider bite is minor and causes nothing more than local irritation. Some spiders can cause significant morbidity and rarely, mortality. Lay identification of the spider has not been shown to be reliable. Latrodectism (red back spider envenomation) is characterised by pain (local, radiating, and regional); systemic symptoms occur less commonly. Funnel web spider bite is a medical emergency; a pressure immobilisation bandage should be applied and the patient transferred to a hospital with available antivenom and resuscitation facilities. Clinicians must consider spider bite in the differential diagnosis of unexplained autonomic and neurological dysfunction, particularly in children. In Australia, skin ulceration is more likely to be an infective, inflammatory or traumatic cause than a case of necrotising arachnidism.

  14. PATHWAYS TO SPIDER PHOBIA

    NARCIS (Netherlands)

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

    1992-01-01

    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

  15. 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).

  16. 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…

  17. Low-Tech, Pilot Scale Purification of a Recombinant Spider Silk Protein Analog from Tobacco Leaves

    Directory of Open Access Journals (Sweden)

    René Heppner

    2016-10-01

    Full Text Available Spider dragline is used by many members of the Araneae family not only as a proteinogenic safety thread but also for web construction. Spider dragline has been shown to possess high tensile strength in combination with elastic behavior. This high tensile strength can be attributed to the presence of antiparallel β-sheets within the thread; these antiparallel β-sheets are why the protein is classified as a silk. Due to the properties of spider silk and its technical and medical uses, including its use as a suture material and as a scaffold for tissue regeneration, spider dragline is a focus of the biotechnology industry. The production of sufficient amounts of spider silk is challenging, as it is difficult to produce large quantities of fibers because of the cannibalistic behavior of spiders and their large spatial requirements. In recent years, the heterologous expression of genes coding for spider silk analogs in various hosts, including plants such as Nicotiana tabacum, has been established. We developed a simple and scalable method for the purification of a recombinant spider silk protein elastin-like peptide fusion protein (Q-/K-MaSp1-100× ELP after heterologous production in tobacco leaves involving heat and acetone precipitation. Further purification was performed using centrifugal Inverse Transition Cycling (cITC. Up to 400 mg of highly pure spider silk protein derivatives can be isolated from six kilograms of tobacco leaves, which is the highest amount of silk protein derivatives purified from plants thus far.

  18. Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution.

    Science.gov (United States)

    Clarke, Thomas H; Garb, Jessica E; Hayashi, Cheryl Y; Arensburger, Peter; Ayoub, Nadia A

    2015-06-08

    The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae). © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. Low-Tech, Pilot Scale Purification of a Recombinant Spider Silk Protein Analog from Tobacco Leaves.

    Science.gov (United States)

    Heppner, René; Weichert, Nicola; Schierhorn, Angelika; Conrad, Udo; Pietzsch, Markus

    2016-10-09

    Spider dragline is used by many members of the Araneae family not only as a proteinogenic safety thread but also for web construction. Spider dragline has been shown to possess high tensile strength in combination with elastic behavior. This high tensile strength can be attributed to the presence of antiparallel β-sheets within the thread; these antiparallel β-sheets are why the protein is classified as a silk. Due to the properties of spider silk and its technical and medical uses, including its use as a suture material and as a scaffold for tissue regeneration, spider dragline is a focus of the biotechnology industry. The production of sufficient amounts of spider silk is challenging, as it is difficult to produce large quantities of fibers because of the cannibalistic behavior of spiders and their large spatial requirements. In recent years, the heterologous expression of genes coding for spider silk analogs in various hosts, including plants such as Nicotiana tabacum, has been established. We developed a simple and scalable method for the purification of a recombinant spider silk protein elastin-like peptide fusion protein (Q-/K-MaSp1-100× ELP) after heterologous production in tobacco leaves involving heat and acetone precipitation. Further purification was performed using centrifugal Inverse Transition Cycling (cITC). Up to 400 mg of highly pure spider silk protein derivatives can be isolated from six kilograms of tobacco leaves, which is the highest amount of silk protein derivatives purified from plants thus far.

  20. 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.

  1. Navigating cancer using online communities: a grounded theory of survivor and family experiences.

    Science.gov (United States)

    Harkin, Lydia Jo; Beaver, Kinta; Dey, Paola; Choong, Kartina

    2017-05-03

    People affected by cancer often have unmet emotional and social support needs. Online cancer communities are a convenient channel for connecting cancer survivors, allowing them to support one another. However, it is unclear whether online community use makes a meaningful contribution to cancer survivorship, as little previous research has examined the experience of using contemporary cancer communities. We aimed to explore the experiences of visitors to online cancer communities. Twenty-three in-depth interviews were conducted with online cancer community visitors, including cancer survivors (n = 18), family members (n = 2), and individuals who were both a survivor and family member (n = 3). Interviews were analysed using a grounded theory approach. A theory developed explaining how individuals 'navigated' the experience of cancer using online cancer communities. Online advice and information led participants on a 'journey to become informed'. Online friendships normalised survivorship and cast participants on a 'journey to recreate identity'. Participants navigated a 'journey through different worlds' as they discovered relevant and hidden communities. This theory highlights virtual paths people affected by cancer can take to self-manage their experience of the disease. Online community experiences can be improved by promoting online evaluation skills and signposting visitors to bereavement support. Cancer survivors can benefit through both lurking and posting in online communities. However, individuals risk becoming distressed when they befriend individuals who may soon die. Additionally, people affected by rarer cancers can struggle to find shared experiences online and may need to look elsewhere for support.

  2. Negotiating a Place in the Family-A Grounded Theory Exploration of Stepgrandmothers' Enactment of Roles.

    Science.gov (United States)

    Chapman, Ashton; Ganong, Lawrence; Coleman, Marilyn; Kang, Youngjin; Sanner, Caroline; Russell, Luke T

    2016-08-12

    Stepgrandparents are becoming more common, and they can, and often do, provide affective and instrumental support to families. Little is known, however, about how they negotiate and enact their roles within families, especially with stepgrandchildren. Stepgrandmothers warrant special attention because researchers have found that women experience more challenges than men in stepfamilies. Guided by symbolic interactionism, the purposes of our study were: (a) to explore stepgrandmothers' role enactment and (b) to explore the intrapersonal, interpersonal, and contextual factors that contribute to role enactment in intergenerational steprelationships. Eighteen stepgrandmothers participated in semi-structured interviews, discussing their relationships with 94 stepgrandchildren. Consistent with grounded theory methods, data collection and analysis occurred simultaneously. Interviews with stepgrandmothers revealed that they spend considerable time and energy defining their roles with stepgrandchildren. Stepgrandmothers' role enactment is a complex, reflexive process. A few perceived that their roles were shaped by their own dispositions, desires, and expectations (evidence for role-making), but most stepgrandmothers described their roles as reflecting the dispositions, desires, and expectations of others (evidence for role-taking). Stepgrandmothers reflected on their roles as a delicate balance of intra- and inter-personal negotiations, operating within cultural expectations. Findings draw attention to the complex nature of role-taking, role-making, and gendered, relational processes in multigenerational stepfamilies. We discuss implications for research and theory related to stepgrandmotherhood as an incomplete institution. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Finding common ground to achieve a “good death”: family physicians working with substitute decision-makers of dying patients. A qualitative grounded theory study

    Directory of Open Access Journals (Sweden)

    Tan Amy

    2013-01-01

    Full Text Available Abstract Background Substitute decision-makers are integral to the care of dying patients and make many healthcare decisions for patients. Unfortunately, conflict between physicians and surrogate decision-makers is not uncommon in end-of-life care and this could contribute to a “bad death” experience for the patient and family. We aim to describe Canadian family physicians’ experiences of conflict with substitute decision-makers of dying patients to identify factors that may facilitate or hinder the end-of-life decision-making process. This insight will help determine how to best manage these complex situations, ultimately improving the overall care of dying patients. Methods Grounded Theory methodology was used with semi-structured interviews of family physicians in Edmonton, Canada, who experienced conflict with substitute decision-makers of dying patients. Purposeful sampling included maximum variation and theoretical sampling strategies. Interviews were audio-taped, and transcribed verbatim. Transcripts, field notes and memos were coded using the constant-comparative method to identify key concepts until saturation was achieved and a theoretical framework emerged. Results Eleven family physicians with a range of 3 to 40 years in clinical practice participated. The family physicians expressed a desire to achieve a “good death” and described their role in positively influencing the experience of death. Finding Common Ground to Achieve a “Good Death” for the Patient emerged as an important process which includes 1 Building Mutual Trust and Rapport through identifying key players and delivering manageable amounts of information, 2 Understanding One Another through active listening and ultimately, and 3 Making Informed, Shared Decisions. Facilitators and barriers to achieving Common Ground were identified. Barriers were linked to conflict. The inability to resolve an overt conflict may lead to an impasse at any point. A process for

  4. Finding common ground to achieve a "good death": family physicians working with substitute decision-makers of dying patients. A qualitative grounded theory study.

    Science.gov (United States)

    Tan, Amy; Manca, Donna

    2013-01-22

    Substitute decision-makers are integral to the care of dying patients and make many healthcare decisions for patients. Unfortunately, conflict between physicians and surrogate decision-makers is not uncommon in end-of-life care and this could contribute to a "bad death" experience for the patient and family. We aim to describe Canadian family physicians' experiences of conflict with substitute decision-makers of dying patients to identify factors that may facilitate or hinder the end-of-life decision-making process. This insight will help determine how to best manage these complex situations, ultimately improving the overall care of dying patients. Grounded Theory methodology was used with semi-structured interviews of family physicians in Edmonton, Canada, who experienced conflict with substitute decision-makers of dying patients. Purposeful sampling included maximum variation and theoretical sampling strategies. Interviews were audio-taped, and transcribed verbatim. Transcripts, field notes and memos were coded using the constant-comparative method to identify key concepts until saturation was achieved and a theoretical framework emerged. Eleven family physicians with a range of 3 to 40 years in clinical practice participated.The family physicians expressed a desire to achieve a "good death" and described their role in positively influencing the experience of death.Finding Common Ground to Achieve a "Good Death" for the Patient emerged as an important process which includes 1) Building Mutual Trust and Rapport through identifying key players and delivering manageable amounts of information, 2) Understanding One Another through active listening and ultimately, and 3) Making Informed, Shared Decisions. Facilitators and barriers to achieving Common Ground were identified. Barriers were linked to conflict. The inability to resolve an overt conflict may lead to an impasse at any point. A process for Resolving an Impasse is described. A novel framework for developing

  5. Annotated Check List of the Spiders (Araneae) of the Mountain Zebra National Park

    OpenAIRE

    Anna S. Dippenaar-Schoeman

    1988-01-01

    A preliminary check list of the spider fauna of the Mountain Zebra National Park is given. Sixteen families, comprising 29 genera and 32 species, are recorded. Observations on the distribution, diagnostic morphology and behaviour of 15 species are given.

  6. 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.

  7. 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 properties a

  8. Spiders associated with papaya, Carica papaya L., in Puerto Rico

    Science.gov (United States)

    The main objective of this work was to study the species composition and population dynamics of spiders associated with papaya plantings in three papaya production areas: Corozal, Isabela, and Lajas, Puerto Rico. Nineteen species representing seven families and 15 genera were identified. Members of ...

  9. Spiders (Arachnida: Araneae) Of Milbridge, Washington County, Maine

    Science.gov (United States)

    Daniel T. Jennings; Frank Jr. Graham

    2007-01-01

    An inventory or spiders associated with diverse habitats of Milbridge, a 6,290-ha area of the East Coastal BioPhysical Region, yielded 6,979 individuals of 19 families, 145 genera, and 302 species (4 unknown). Species richness per genus ranged from 1 to 13, with 88 genera represented by a single species. Total species composition favored web spinners over hunters;...

  10. 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

  11. Molecular spiders on a plane

    Science.gov (United States)

    Antal, Tibor; Krapivsky, P. L.

    2012-06-01

    Synthetic biomolecular spiders with “legs” made of single-stranded segments of DNA can move on a surface covered by single-stranded segments of DNA called substrates when the substrate DNA is complementary to the leg DNA. If the motion of a spider does not affect the substrates, the spider behaves asymptotically as a random walk. We study the diffusion coefficient and the number of visited sites for spiders moving on the square lattice with a substrate in each lattice site. The spider's legs hop to nearest-neighbor sites with the constraint that the distance between any two legs cannot exceed a maximal span. We establish analytic results for bipedal spiders, and investigate multileg spiders numerically. In experimental realizations legs usually convert substrates into products (visited sites). The binding of legs to products is weaker, so the hopping rate from the substrates is smaller. This makes the problem non-Markovian and we investigate it numerically. We demonstrate the emergence of a counterintuitive behavior—the more spiders are slowed down on unvisited sites, the more motile they become.

  12. Spider fauna of semi-dry grasslands on a military training base in Northwest Germany (Münster

    Directory of Open Access Journals (Sweden)

    Buchholz, Sascha

    2008-07-01

    Full Text Available The spider fauna of semi-dry grasslands on the military training area of Dorbaum near Münster (North Rhine-Westphalia was investigated. From 2002 to 2003 a total of 11,194 mature spiders from 141 species and 20 families was caught by pitfall trapping and hand sampling. Among them are 18 species listed in the Red Data Book of North Rhine-Westphalia, four species are rare or previously rarely recorded. Most of the spiders are habitat generalists that extend their occurrence into all types of habitats, while the number of species which are stenotopic to sand habitats is noticeably low (n = 13. The spider data were analysed with Principal Component Analysis (PCA. It is possible to distinguish spider communities of neighbouring forested habitats from species groups of open habitats, but there is no uniform spider community which is characteristic for semi-dry grassland.

  13. Family interaction and communication deviance in disturbed and normal families. Questions of strategy: rejoinder to Jacob and Grounds.

    Science.gov (United States)

    Doane, J A

    1978-09-01

    Perhaps the best way to respond to Jacob and Grounds' critique is to focus on the more important issues they raise and to clarify some of the apparent confusion. It seems there are several general classes of criticism that Jacob and Grounds have offered: arbitrariness in selection of studies, inconsistency in reporting findings, inaccuracies in the data reported, and an overly favorable conclusion with respect to the communication deviance literature. Each of these issues will be dealt with here, using as many specific illustrations and examples as space permits.

  14. The transition experience of rural older persons with advanced cancer and their families: a grounded theory study

    Directory of Open Access Journals (Sweden)

    Berry Patricia H

    2010-04-01

    Full Text Available Abstract Background Transitions often occur suddenly and can be traumatic to both patients with advanced disease and their families. The purpose of this study was to explore the transition experience of older rural persons with advanced cancer and their families from the perspective of palliative home care patients, bereaved family caregivers, and health care professionals. The specific aims were to: (1 describe the experience of significant transitions experienced by older rural persons who were receiving palliative home care and their families and (2 develop a substantive theory of transitions in this population. Methods Using a grounded theory approach, 27 open-ended individual audio-taped interviews were conducted with six older rural persons with advanced cancer and 10 bereaved family caregivers. Four focus group interviews were conducted with 12 palliative care health care professionals. All interviews were transcribed verbatim, coded, and analyzed using Charmaz's constructivist grounded theory approach. Results Within a rural context of isolation, lack of information and limited accessibility to services, and values of individuality and community connectedness, older rural palliative patients and their families experienced multiple complex transitions in environment, roles/relationships, activities of daily living, and physical and mental health. Transitions disrupted the lives of palliative patients and their caregivers, resulting in distress and uncertainty. Rural palliative patients and their families adapted to transitions through the processes of "Navigating Unknown Waters". This tentative theory includes processes of coming to terms with their situation, connecting, and redefining normal. Timely communication, provision of information and support networks facilitated the processes. Conclusion The emerging theory provides a foundation for future research. Significant transitions identified in this study may serve as a focus for

  15. Toward spinning artificial spider silk.

    Science.gov (United States)

    Rising, Anna; Johansson, Jan

    2015-05-01

    Spider silk is strong and extensible but still biodegradable and well tolerated when implanted, making it the ultimate biomaterial. Shortcomings that arise in replicating spider silk are due to the use of recombinant spider silk proteins (spidroins) that lack native domains, the use of denaturing conditions under purification and spinning and the fact that the understanding of how spiders control silk formation is incomplete. Recent progress has unraveled the molecular mechanisms of the spidroin N- and C-terminal nonrepetitive domains (NTs and CTs) and revealed the pH and ion gradients in spiders' silk glands, clarifying how spidroin solubility is maintained and how silk is formed in a fraction of a second. Protons and CO2, generated by carbonic anhydrase, affect the stability and structures of the NT and CT in different ways. These insights should allow the design of conditions and devices for the spinning of recombinant spidroins into native-like silk.

  16. Reversible myocarditis after spider bite.

    Science.gov (United States)

    Kara, Hasan; Ak, Ahmet; Bayir, Aysegul; Avci, Ahmet

    2013-04-08

    Black widow spiders (Latrodectus tredecimguttatus) are poisonous spiders endemic in Turkey. Latrodectus bites may cause myocarditis with increased cardiac enzymes. We treated two men (aged 20 and 33 years) who had myocarditis after black spider bites with leucocytosis and elevated levels of troponin I, creatine kinase and creatine kinase-MB fraction. Both patients had normal results on an ECG, and one patient had abnormal echocardiography with minimal left ventricular wall movement disorder. Both patients were hospitalised in the intensive care unit and treated with intravenous fluids, analgesics, spasmolytic drugs, tetanus prophylaxis and cardiac monitoring. The levels of troponin I, creatine kinase and creatine kinase-MB fraction improved, and the patients were discharged home on the third and fifth hospital day without complications. Myocarditis after a Latrodectus bite is rare, but may be associated with serious complications. Therefore, in regions endemic with Latrodectus spiders, prudent treatment of spider bites may include cardiac evaluation and monitoring.

  17. Transcriptome analysis of venom glands from a single fishing spider Dolomedes mizhoanus.

    Science.gov (United States)

    Jiang, Liping; Liu, Changjun; Duan, Zhigui; Deng, Meichun; Tang, Xing; Liang, Songping

    2013-10-01

    The spider venom is a large pharmacological repertoire composed of different types of bioactive peptide toxins. Despite the importance of spider toxins in capturing terrestrial prey and defending themselves against predators, we know little about the venom components from the spider acting on the fish. Here we constructed a cDNA library of a pair of venomous glands from a single fish-hunting spider Dolomedes mizhoanus. A total of 356 high-quality expressed sequence tags (ESTs) were obtained from the venom gland cDNA library and analyzed. These transcripts were further classified into 45 clusters (19 contigs and 26 singletons), most of which encoded cystine knot toxins (CKTs) and non-CKTs. The ESTs coding for 53 novel CKT precursors were abundant transcripts in the venom glands of the spider D. mizhoanus, accounting for 76% of the total ESTs, the precursors of which were grouped into six families based on the sequence identity and the phylogenetic analysis. In addition, the non-CKTs deduced from 21% of the total ESTs were annotated by Gene Ontology terms and eukaryotic orthologous groups. Fifty-five CKT precursors deduced from 273 ESTs are the largest dataset for a single spider specimen to date. The results may contribute to discovering novel potential drug leads from spider venoms and a better understanding of the evolutionary relationship of the spider toxin.

  18. Economic analysis of spider web airline networks

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The distinct network organization, management, service and operating characteristics of US Southwest Airlines are key elements of its success compared with other airlines. As a network organization type, the spider web airline network has received more attention. In this paper, we analyzed the relation between the spider web airline network and spider web, and the structure of spider web airline network, built the assignment model of the spider web airline network,and investigated the economics concerned.

  19. 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.

  20. 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.

  1. Mental health professional support in families with a member suffering from severe mental illness: a grounded theory model.

    Science.gov (United States)

    Gavois, Helena; Paulsson, Gun; Fridlund, Bengt

    2006-03-01

    The aim of this study was to develop a model of mental health professional (MHP) support based on the needs of families with a member suffering from severe mental illness (SMI). Twelve family members were interviewed with the focus on their needs of support by MHP, then the interviews were analyzed according to the grounded theory method. The generated model of MHP support had two core categories: the family members' process from crisis to recovery and their interaction with the MHP about mental health/illness and daily living of the person with SMI. Interaction based on ongoing contact between MHP and family members influenced the family members' process from crisis towards recovery. Four MHP strategies--being present, listening, sharing and empowering--met the family members' needs of support in the different stages of the crisis. Being present includes early contact, early information and protection by MHP at onset of illness or relapse. Listening includes assessing burden, maintaining contact and confirmation in daily living for the person with SMI. Sharing between MHP and family members includes co-ordination, open communication and security in daily living for the person with SMI. Finally, the MHP strategy empowering includes creating a context, counselling and encouraging development for the family members. The present model has a holistic approach and can be used as an overall guide for MHP support in clinical care of families of persons with SMI. For future studies, it is important to study the interaction of the family with SMI and the connection between hope, coping and empowerment.

  2. Addition of a spider family for Uruguay: First record of Iviraiva pachyura (Mello-Leitão, 1935 (Araneae: Hersiliidae, with notes on its natural history and distribution

    Directory of Open Access Journals (Sweden)

    Álvaro Laborda

    2015-08-01

    Full Text Available This is the first record for the species Iviraiva pachyura and for the family Hersiliidae in Uruguay.  Data presented represent the southernmost record for the species.  Figures of living specimens, copulatory organs and a description of the egg sac are provided. The distribution of the species is shown and discussed. 

  3. Addition of a spider family for Uruguay: First record of Iviraiva pachyura (Mello-Leitão, 1935 (Araneae: Hersiliidae, with notes on its natural history and distribution

    Directory of Open Access Journals (Sweden)

    Álvaro Laborda

    2015-08-01

    Full Text Available This is the first record for the species Iviraiva pachyura and for the family Hersiliidae in Uruguay.  Data presented represent the southernmost record for the species.  Figures of living specimens, copulatory organs and a description of the egg sac are provided. The distribution of the species is shown and discussed. 

  4. Molecular characterization and evolutionary study of spider tubuliform (eggcase) silk protein.

    Science.gov (United States)

    Tian, Maozhen; Lewis, Randolph V

    2005-06-01

    As a result of hundreds of millions of years of evolution, orb-web-weaving spiders have developed the use of seven different silks produced by different abdominal glands for various functions. Tubuliform silk (eggcase silk) is unique among these spider silks due to its high serine and very low glycine content. In addition, tubuliform silk is the only silk produced just during a short period of time, the reproductive season, in the spider's life. To understand the molecular characteristics of the proteins composing this silk, we constructed tubuliform-gland-specific cDNA libraries from three different spider families, Nephila clavipes, Argiope aurantia, and Araneus gemmoides. Sequencing of tubuliform silk cDNAs reveals the repetitive architecture of its coding sequence and novel amino acid motifs. The inferred protein, tubuliform spidroin 1 (TuSp1), contains highly homogenized repeats in all three spiders. Amino acid composition comparison of the predicted tubuliform silk protein sequence to tubuliform silk indicates that TuSp1 is the major component of tubuliform silk. Repeat unit alignment of TuSp1 among three spider species shows high sequence conservation among tubuliform silk protein orthologue groups. Sequence comparison among TuSp1 repetitive units within species suggests intragenic concerted evolution, presumably through gene conversion and unequal crossover events. Comparative analysis demonstrates that TuSp1 represents a new orthologue in the spider silk gene family.

  5. The social ecology of resolving family conflict among West African immigrants in New York: a grounded theory approach.

    Science.gov (United States)

    Rasmussen, Andrew; Chu, Tracy; Akinsulure-Smith, Adeyinka M; Keatley, Eva

    2013-09-01

    The current study employs a grounded theory approach to examine West African immigrants' resolution of parent-child conflict and intimate partner conflict. Data from 59 participants present an interactive social ecological framework, where a lack of resolution at one level results in attempts to resolve problems at higher levels. Four levels are identified within West African immigrants' problem solving ecology, each with specific actors in positions of authority: individual/dyadic (parents and spouses), extended family (which includes distant relatives and relatives living in home countries), community leadership (non-family elders and religious leaders), and state authorities. From participants' descriptions of family challenges emerged a picture of a social ecology in flux, with traditional, socially conservative modes of resolving family conflict transposed across migration into the more liberal and state-oriented familial context of the United States. This transposition results in a loss spiral for the traditional social ecology, differentially affecting individual actors within families. Implications for helping professionals working with new immigrant communities include identifying variability in openness to adapting structures that are not working well (e.g., patriarchal protection of abusive husbands) and supporting structures known to be associated with well being (e.g., collective monitoring of youth).

  6. Collective Order within Family; An Axial Phenomenon regarding the Effect of Islamic Teachings on the ‎Economic Action of Family: A Study Based on the Grounded Theory

    Directory of Open Access Journals (Sweden)

    ‎ V. Arshadi

    2016-02-01

    Full Text Available The present article aims to identify the intermediate factors regarding the effect of Islamic teachings on family economic action through an interpretative and multifactorial approach. The method is qualitative and is based on grounded theory method”. Due to the interdisciplinary nature of the matter, a semi-structured interview with 16 experts on Islamic economy, Muslim consumer behavior, educational sciences, psychology and sociology and the issue of values and actions has served as the main research tool. The samples were selected through purposive sampling and snowball method, and interviews were conducted to the point of theoretical saturation. Findings of data analysis in this three steps show that factors such as the synergy of the high quality of transfer of teachings from formal and informal education institutes, high quality of the perception of teachings by family members, high quality of family income resources, and faith and belief in the accountability in the Hereafter can create collective order within family based on the subjective value of Islamic economic teaching. The collective order is influenced by "underlying" and "structural" factors and leads to discretion behavior. This paper is also innovative in terms of its profound look into the formation of economic behavior within the family.

  7. Ant exclusion in citrus over an 8-year period reveals a pervasive yet changing effect of ants on a Mediterranean spider assemblage.

    Science.gov (United States)

    Mestre, L; Piñol, J; Barrientos, J A; Espadaler, X

    2013-09-01

    Ants and spiders are ubiquitous generalist predators that exert top-down control on herbivore populations. Research shows that intraguild interactions between ants and spiders can negatively affect spider populations, but there is a lack of long-term research documenting the strength of such interactions and the potentially different effects of ants on the diverse array of species in a spider assemblage. Similarly, the suitability of family-level surrogates for finding patterns revealed by species-level data (taxonomic sufficiency) has almost never been tested in spider assemblages. We present a long-term study in which we tested the impact of ants on the spider assemblage of a Mediterranean citrus grove by performing sequential 1-year experimental exclusions on tree canopies for 8 years. We found that ants had a widespread influence on the spider assemblage, although the effect was only evident in the last 5 years of the study. During those years, ants negatively affected many spiders, and effects were especially strong for sedentary spiders. Analyses at the family level also detected assemblage differences between treatments, but they concealed the different responses to ant exclusion shown by some related spider species. Our findings show that the effects of experimental manipulations in ecology can vary greatly over time and highlight the need for long-term studies to document species interactions.

  8. THREE NEW SPECIES OF THE SPIDER FAMILY THERIDIIDAE(ARACHNIDA, ARANEAE) FROM CHINA%中国球蛛科三新种(蛛形纲,蜘蛛目)

    Institute of Scientific and Technical Information of China (English)

    尹长民; 彭贤锦; 张永靖

    2005-01-01

    记述了球蛛科Theridiidae 3新种,肋脊球蛛Therid-ion carinatumsp.noV.,双凹球蛛Theridion bidepressum sp.noV.和蝶斑高蛛Takayus papiliomaculatus sp.nov.%During checking the specimens collected from Hunan Province, three new species of the family Theridiidae have been identified. They are named Theridion carinatum sp. nov. , T. bidepressum sp. nov. and Takayus papiliomaculatus sp. nov. Type specimens are deposited at the College of Life Sciences, Hunan Normal University, (HNU). Measurements of this paper given are in millimeter (mm).

  9. 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.

  10. An orb-weaver spider exploits an ant–acacia mutualism for enemy-free space

    OpenAIRE

    Styrsky, John D

    2014-01-01

    Exploiters of protection mutualisms are assumed to represent an important threat for the stability of those mutualisms, but empirical evidence for the commonness or relevance of exploiters is limited. Here, I describe results from a manipulative study showing that an orb-weaver spider, Eustala oblonga, inhabits an ant-acacia for protection from predators. This spider is unique in the orb-weaver family in that it associates closely with both a specific host plant and ants. I tested the protect...

  11. Cell culture's spider silk road.

    Science.gov (United States)

    Perkel, Jeffrey

    2014-06-01

    A number of synthetic and natural materials have been tried in cell culture and tissue engineering applications in recent years. Now Jeffrey Perkel takes a look at one new culture component that might surprise you-spider silk.

  12. Studies on Tropical Pholcidae I Panjange, a new genus of Indo-Australian Leaf- and rock-dwelling Pholcid spiders (Araneae)

    NARCIS (Netherlands)

    Deeleman-Reinhold, C.L.; Deeleman, P.R.

    1983-01-01

    The study of tropical spiders was taken up in the last part of the nineteenth century by Thorell, Simon and others, but since then passed through a long dormant stage. Only during the last few decades there was some revival. In particular numerous spider species from leaf-litter, ground debris, etc.

  13. SPIDER: a balloon-borne CMB polarimeter for large angular scales

    CERN Document Server

    Filippini, J P; Amiri, M; Benton, S J; Bihary, R; Bock, J J; Bond, J R; Bonetti, J A; Bryan, S A; Burger, B; Chiang, H C; Contaldi, C R; Crill, B P; Doré, O; Farhang, M; Fissel, L M; Gandilo, N N; Golwala, S R; Gudmundsson, J E; Halpern, M; Hasselfield, M; Hilton, G; Holmes, W; Hristov, V V; Irwin, K D; Jones, W C; Kuo, C L; MacTavish, C J; Mason, P V; Montroy, T E; Morford, T A; Netterfield, C B; O'Dea, D T; Rahlin, A S; Reintsema, C D; Ruhl, J E; Runyan, M C; Schenker, M A; Shariff, J A; Soler, J D; Trangsrud, A; Tucker, C; Tucker, R S; Turner, A D

    2011-01-01

    We describe SPIDER, a balloon-borne instrument to map the polarization of the millimeter-wave sky with degree angular resolution. Spider consists of six monochromatic refracting telescopes, each illuminating a focal plane of large-format antenna-coupled bolometer arrays. A total of 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. A cold half-wave plate at the aperture of each telescope modulates the polarization of incoming light to control systematics. Spider's first flight will be a 20-30-day Antarctic balloon campaign in December 2011. This flight will map \\sim8% of the sky to achieve unprecedented sensitivity to the polarization signature of the gravitational wave background predicted by inflationary cosmology. The Spider mission will also serve as a proving ground for these detector technologies in preparation for a future satellite mission.

  14. A Tank Bromeliad Favors Spider Presence in a Neotropical Inundated Forest.

    Directory of Open Access Journals (Sweden)

    Yann Hénaut

    Full Text Available Tank bromeliads are good models for understanding how climate change may affect biotic associations. We studied the relationships between spiders, the epiphytic tank bromeliad, Aechmea bracteata, and its associated ants in an inundated forest in Quintana Roo, Mexico, during a drought period while, exceptionally, this forest was dry and then during the flooding that followed. We compared spider abundance and diversity between 'Aechmea-areas' and 'control-areas' of the same surface area. We recorded six spider families: the Dipluridae, Ctenidae, Salticidae, Araneidae, Tetragnathidae and Linyphiidae among which the funnel-web tarantula, Ischnothele caudata, the only Dipluridae noted, was the most abundant. During the drought period, the spiders were more numerous in the Aechmea-areas than in the control-areas, but they were not obligatorily associated with the Aechmea. During the subsequent flooding, the spiders were concentrated in the A. bracteata patches, particularly those sheltering an ant colony. Also, a kind of specificity existed between certain spider taxa and ant species, but varied between the drought period and subsequent flooding. We conclude that climatic events modulate the relationship between A. bracteata patches and their associated fauna. Tank bromeliads, previously considered only for their ecological importance in supplying food and water during drought, may also be considered refuges for spiders during flooding. More generally, tank bromeliads have an important role in preserving non-specialized fauna in inundated forests.

  15. Climatic Variables Do Not Directly Predict Spider Richness and Abundance in Semiarid Caatinga Vegetation, Brazil.

    Science.gov (United States)

    Carvalho, Leonardo S; Sebastian, Nicholas; Araújo, Helder F P; Dias, Sidclay C; Venticinque, Eduardo; Brescovit, Antonio D; Vasconcellos, Alexandre

    2015-02-01

    Spiders are abundant in tropical ecosystems and exert predatory pressure on a wide variety of invertebrate populations and also serve as prey for many others organisms, being part of complex interrelationships influenced directly and indirectly by a myriad of factors. We examined the influence of biotic (i.e., prey availability) and abiotic (i.e., temperature, precipitation, relative humidity, real evapotranspiration) factors on species richness and abundance during a two-year period in the semiarid Caatinga vegetation in northeastern Brazil. Data were analyzed through partial autocorrelation functions, cross correlations, and a path analysis. A total of 2522 spiders were collected with beating tray, pit-fall traps, and malaise traps, comprising 91 species and 34 families. Spider abundance peaked in the rainy season. Our results suggest that total invertebrate abundance has a direct influence on spider richness and abundance, whereas the effects of precipitation were mainly indirectly related to most spider assemblage parameters. The increase in vegetation cover with the rainy season in the Caatinga provides more breeding and foraging sites for spiders and stimulates their activities. Additionally, rainfall in arid and semiarid ecosystems stimulated the activity and reproduction of many herbivore and detritivore invertebrates dependent on plant biomass and necromass consumption, leading to an increase in spider prey availability. © The Author 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. The allometry of CNS size and consequences of miniaturization in orb-weaving and cleptoparasitic spiders.

    Science.gov (United States)

    Quesada, Rosannette; Triana, Emilia; Vargas, Gloria; Douglass, John K; Seid, Marc A; Niven, Jeremy E; Eberhard, William G; Wcislo, William T

    2011-11-01

    Allometric studies of the gross neuroanatomy of adults from nine species of spiders from six web-weaving families (Orbicularia), and nymphs from six of these species, show that very small spiders resemble other small animals in having disproportionately larger central nervous systems (CNSs) relative to body mass when compared with large-bodied forms. Small spiderlings and minute adult spiders have similar relative CNS volumes. The relatively large CNS of a very small spider occupies up to 78% of the cephalothorax volume. The CNSs of very small spiders extend into their coxae, occupying as much as 26% of the profile area of the coxae of an Anapisona simoni spiderling (body mass spiders also have reduced neuronal cell body diameters. The adults of nearly all orbicularian spiders weave prey capture webs, as do the spiderlings, beginning with second instar nymphs. Comparable allometric relations occur in adults of both orb-weaving and cleptoparasitic species, indicating that this behavioral difference is not reflected in differences in gross CNS allometry. Published by Elsevier Ltd.

  17. Comparative growth and development of spiders reared on live and dead prey.

    Science.gov (United States)

    Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C

    2013-01-01

    Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific.

  18. Post-secretion processing influences spider silk performance

    Science.gov (United States)

    Blamires, Sean J.; Wu, Chung-Lin; Blackledge, Todd A.; Tso, I-Min

    2012-01-01

    Phenotypic variation facilitates adaptations to novel environments. Silk is an example of a highly variable biomaterial. The two-spidroin (MaSp) model suggests that spider major ampullate (MA) silk is composed of two proteins—MaSp1 predominately contains alanine and glycine and forms strength enhancing β-sheet crystals, while MaSp2 contains proline and forms elastic spirals. Nonetheless, mechanical properties can vary in spider silks without congruent amino acid compositional changes. We predicted that post-secretion processing causes variation in the mechanical performance of wild MA silk independent of protein composition or spinning speed across 10 species of spider. We used supercontraction to remove post-secretion effects and compared the mechanics of silk in this ‘ground state’ with wild native silks. Native silk mechanics varied less among species compared with ‘ground state’ silks. Variability in the mechanics of ‘ground state’ silks was associated with proline composition. However, variability in native silks did not. We attribute interspecific similarities in the mechanical properties of native silks, regardless of amino acid compositions, to glandular processes altering molecular alignment of the proteins prior to extrusion. Such post-secretion processing may enable MA silk to maintain functionality across environments, facilitating its function as a component of an insect-catching web. PMID:22628213

  19. Post-secretion processing influences spider silk performance.

    Science.gov (United States)

    Blamires, Sean J; Wu, Chung-Lin; Blackledge, Todd A; Tso, I-Min

    2012-10-07

    Phenotypic variation facilitates adaptations to novel environments. Silk is an example of a highly variable biomaterial. The two-spidroin (MaSp) model suggests that spider major ampullate (MA) silk is composed of two proteins-MaSp1 predominately contains alanine and glycine and forms strength enhancing β-sheet crystals, while MaSp2 contains proline and forms elastic spirals. Nonetheless, mechanical properties can vary in spider silks without congruent amino acid compositional changes. We predicted that post-secretion processing causes variation in the mechanical performance of wild MA silk independent of protein composition or spinning speed across 10 species of spider. We used supercontraction to remove post-secretion effects and compared the mechanics of silk in this 'ground state' with wild native silks. Native silk mechanics varied less among species compared with 'ground state' silks. Variability in the mechanics of 'ground state' silks was associated with proline composition. However, variability in native silks did not. We attribute interspecific similarities in the mechanical properties of native silks, regardless of amino acid compositions, to glandular processes altering molecular alignment of the proteins prior to extrusion. Such post-secretion processing may enable MA silk to maintain functionality across environments, facilitating its function as a component of an insect-catching web.

  20. [Spider bites: araneidism of medical importance].

    Science.gov (United States)

    Pommier, Philip; Rollard, Christine; De Haro, Luc

    2005-01-15

    LIMITED RISKS: Although most species of spiders are venomous, only ten or so are able to induce human envenomations. From a systematic point of view, it is possible to distinguish the araneomorph spiders - or "true" spiders - from the mygalomorph spiders. Dangerous species for humans can be found in both groups. Regarding "true' spiders, two kinds of envenomation are frequent, ubiquitous and potentially severe: latrodectism (neurotoxic symptomatology) due to the Widow spiders of the Latrodectus species,and loxoscelism (viscero-cutaneous symptomatology). Regarding the mygalomorph spiders, the Australian species responsible for atraxism (neurotoxic symptomatology) are considered as the most dangerous. Most of the other mygalomorph spiders, when they bite, only provoke benign loco regional problems. A supplementary defensive weapon exists in certain South-American species: urticating hairs which may induce severe ocular damage.

  1. 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.

  2. 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.

  3. Decoding the secrets of spider silk

    OpenAIRE

    Lukas Eisoldt; Andrew Smith; Thomas Scheibel

    2011-01-01

    Spider silks have been employed by man for several thousands of years. Spider silks possess extraordinary mechanical properties due to a combination of strength and extensibility that are superior to most man-made fibers. Spider silk fibers are a protein-based material produced in a highly sophisticated hierarchical process under mild conditions. Here, we review the current understanding of spider silk and its assembly process, as well as discuss the application of silk-based materials to the...

  4. Hey! A Brown Recluse Spider Bit Me!

    Science.gov (United States)

    ... can sometimes be hard to diagnose a spider bite correctly. The spider can be killed first before you bring it ... is really damaged at the area of the bite. (A skin graft is when a small amount ... getting bitten by brown recluse spiders is to be careful in areas where they ...

  5. Brown recluse spider bite on the breast.

    Science.gov (United States)

    Norris, Kori; Misra, Subhasis

    2014-05-01

    Brown recluse spiders are one of two types of spiders in the United States that can cause significant tissue damage and, in rare cases, death. Brown recluse spider bites are most often benign and self-limiting, but in a few cases can cause severe necrotic skin lesions.

  6. Participants' Experiences in Hellinger's Family Constellation Work: A Grounded Theory Study

    Science.gov (United States)

    Georgiadou, Sofia

    2012-01-01

    As a recently introduced to the U.S. model of intergenerational systemic therapy from Germany, Bert Hellinger's Family Constellation Work (FCW) has very limited research support. Hellinger himself has authored a number of publications referencing hundreds of cases, where he implemented his method to approach a broad array of physical,…

  7. 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.

  8. Spider silk reduces insect herbivory.

    Science.gov (United States)

    Rypstra, Ann L; Buddle, Christopher M

    2013-02-23

    The role of predators in food webs extends beyond their ability to kill and consume prey. Such trait-mediated effects occur when signals of the predator influence the behaviour of other animals. Because all spiders are silk-producing carnivores, we hypothesized that silk alone would signal other arthropods and enhance non-lethal effects of spiders. We quantified the herbivory inflicted by two beetle species on green bean plants (Phaseolus vulgaris) in the presence of silkworm silk and spider silk along with no silk controls. Single leaflets were treated and enclosed with herbivores in the laboratory and field. Another set of leaflets were treated and left to experience natural herbivory in the field. Entire plants in the field were treated with silk and enclosed with herbivores or left exposed to herbivory. In all cases, the lowest levels of herbivory occurred with spider silk treatments and, in general, silkworm silk produced intermediate levels of leaf damage. These results suggest that silk may be a mechanism for the trait-mediated impacts of spiders and that it might contribute to integrated pest management programmes.

  9. Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems

    Science.gov (United States)

    Kraus, Johanna M.; Gibson, Polly P.; Walters, David M.; Mills, Marc A.

    2017-01-01

    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 hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinated biphenyls (PCBs) in aquatic ecosystems with high habitat heterogeneity. The spatial pattern of ΣPCB concentrations in 2 common families of riparian spiders sampled in 2011 to 2013 generally tracked spatial variation in sediment ΣPCBs across all sites within the Manistique River Great Lakes Area of Concern (AOC), a rivermouth ecosystem located on the south shore of the Upper Peninsula, Manistique (MI,USA) that includes harbor, river, backwater, and lake habitats. Sediment ΣPCB concentrations normalized for total organic carbon explained 41% of the variation in lipid-normalized spider ΣPCB concentrations across 11 sites. Furthermore, 2 common riparian spider taxa (Araneidae and Tetragnathidae) were highly correlated (r2> 0.78) and had similar mean ΣPCB concentrations when averaged acrossall years. The results indicate that riparian spiders may be useful sentinels of relative PCB availability to aquatic and riparian food webs in heterogeneous aquatic ecosystems like rivermouths where habitat and contaminant variability may make the use of aquatic taxa lesseffective. Furthermore, the present approach appears robust to heterogeneity in shoreline development and riparian vegetation that support different families of large web-building spiders. Environ Toxicol Chem 2016;9999:1–9. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  10. Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems.

    Science.gov (United States)

    Kraus, Johanna M; Gibson, Polly P; Walters, David M; Mills, Marc A

    2017-05-01

    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 hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinated biphenyls (PCBs) in aquatic ecosystems with high habitat heterogeneity. The spatial pattern of ΣPCB concentrations in 2 common families of riparian spiders sampled in 2011 to 2013 generally tracked spatial variation in sediment ΣPCBs across all sites within the Manistique River Great Lakes Area of Concern (AOC), a rivermouth ecosystem located on the south shore of the Upper Peninsula, Manistique (MI, USA) that includes harbor, river, backwater, and lake habitats. Sediment ΣPCB concentrations normalized for total organic carbon explained 41% of the variation in lipid-normalized spider ΣPCB concentrations across 11 sites. Furthermore, 2 common riparian spider taxa (Araneidae and Tetragnathidae) were highly correlated (r(2)  > 0.78) and had similar mean ΣPCB concentrations when averaged across all years. The results indicate that riparian spiders may be useful sentinels of relative PCB availability to aquatic and riparian food webs in heterogeneous aquatic ecosystems like rivermouths where habitat and contaminant variability may make the use of aquatic taxa less effective. Furthermore, the present approach appears robust to heterogeneity in shoreline development and riparian vegetation that support different families of large web-building spiders. Environ Toxicol Chem 2017;36:1278-1286. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is

  11. Reproductive Seasonality in Nesticus (Araneae: Nesticidae) Cave Spiders

    OpenAIRE

    Carver, Linnea M.; Perlaky, Patricia; Cressler, Alan; Kirk S Zigler

    2016-01-01

    Spiders of the family Nesticidae are members of cave communities around the world with cave-obligate (troglobiotic) species known from North America, Europe, Asia and the Indo-Pacific. A radiation of Nesticus (Araneae: Nesticidae) in the southern Appalachians includes ten troglobiotic species. Many of these species are of conservation interest due to their small ranges, with four species being single-cave endemics. Despite conservation concerns and their important role as predators in cave co...

  12. Novel nanocomposites from spider silk–silica fusion (chimeric) proteins

    OpenAIRE

    Wong Po Foo, Cheryl; Patwardhan, Siddharth V.; Belton, David J.; Kitchel, Brandon; Anastasiades, Daphne; Huang, Jia; Naik, Rajesh R.; Perry, Carole C.; Kaplan, David L.

    2006-01-01

    Silica skeletal architectures in diatoms are characterized by remarkable morphological and nanostructural details. Silk proteins from spiders and silkworms form strong and intricate self-assembling fibrous biomaterials in nature. We combined the features of silk with biosilica through the design, synthesis, and characterization of a novel family of chimeric proteins for subsequent use in model materials forming reactions. The domains from the major ampullate spidroin 1 (MaSp1) protein of Neph...

  13. Host specificity and temporal and seasonal shifts in host preference of a web-spider parasitoid Zatypota percontatoria.

    Science.gov (United States)

    Korenko, Stanislav; Michalková, Veronika; Zwakhals, Kees; Pekár, Stano

    2011-01-01

    Current knowledge about polysphinctine parasite wasps' interactions with their spider hosts is very fragmented and incomplete. This study presents the host specificity of Zatypota percontatoria (Müller) (Hymenoptera: Ichneumonidae) and its adaptation to varying host availability. Two years of field observations show that Z. percontatoria is a stenophagous parasitoid that parasitizes only five closely related web-building spiders of the family Theridiidae (Araneae). Within the Theridiidae it attacks only species belonging to a small group of species, here called the "Theridion" group. These hosts have a similar biology, but are available at different levels of abundance and at different sizes over the season. Laboratory experiments showed that this wasp species ignores linyphiid, araneid or dictynid spiders and accepts only theridiid spiders of the "Theridion" group. In the field study, wasp females preferred older juvenile and sub-adult female spider instars with intermediate body size. Only 5% of the parasitized spiders were males. Parasitism in the natural population of theridiid spiders was on average 1.3%. Parasitism was most frequent on two species, Theridion varians Hahn in 2007 and Neottiura bimaculata Linnaeus in 2008. The parasitization rate was positively correlated with spider abundance. The wasp responded adaptively to seasonal changes in host abundance and host body size and shifted host preference according to the availability of suitable hosts during, as well as between, seasons. In spring and summer the highest percentage of parasitism was on T. varians and in autumn it was on N. bimaculata.

  14. 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

  15. Ballooning Spiders: The Case for Electrostatic Flight

    CERN Document Server

    Gorham, Peter W

    2013-01-01

    We consider general aspects of the physics underlying the flight of Gossamer spiders, also known as ballooning spiders. We show that existing observations and the physics of spider silk in the presence of the Earth's static atmospheric electric field indicate a potentially important role for electrostatic forces in the flight of Gossamer spiders. A compelling example is analyzed in detail, motivated by the observed "unaccountable rapidity" in the launching of such spiders from H.M.S. Beagle, recorded by Charles Darwin during his famous voyage.

  16. A case of Spider bite localized to the eyelid.

    Science.gov (United States)

    Bilgili, Serap Gunes; Karadag, Ayse Serap; Karadag, Remzi; Cecen, Ilhan; Calka, Omer

    2013-03-01

    Loxosceles Spiders have a worldwide distribution and are considered one of the most medically important groups of Spiders. The venom from Spiders of the genus Loxosceles, the most famous being Loxosceles reclusa (brown recluse Spider), can promote severe local and systemic damages. This report describes a girl presenting with a Spider bite over her right upper eyelid.

  17. Vibration Propagation in Spider Webs

    Science.gov (United States)

    Hatton, Ross; Otto, Andrew; Elias, Damian

    Due to their poor eyesight, spiders rely on web vibrations for situational awareness. Web-borne vibrations are used to determine the location of prey, predators, and potential mates. The influence of web geometry and composition on web vibrations is important for understanding spider's behavior and ecology. Past studies on web vibrations have experimentally measured the frequency response of web geometries by removing threads from existing webs. The full influence of web structure and tension distribution on vibration transmission; however, has not been addressed in prior work. We have constructed physical artificial webs and computer models to better understand the effect of web structure on vibration transmission. These models provide insight into the propagation of vibrations through the webs, the frequency response of the bare web, and the influence of the spider's mass and stiffness on the vibration transmission patterns. Funded by NSF-1504428.

  18. Swiss prospective study on spider bites.

    Science.gov (United States)

    Gnädinger, Markus; Nentwig, Wolfgang; Fuchs, Joan; Ceschi, Alessandro

    2013-09-04

    Knowledge of spider bites in Central Europe derives mainly from anecdotal case presentations; therefore we aimed to collect cases systematically. From June 2011 to November 2012 we prospectively collected 17 cases of alleged spider bites, and together with two spontaneous notifications later on, our database totaled 19 cases. Among them, eight cases could be verified. The causative species were: Cheiracanthium punctorium (3), Zoropsis spinimana (2), Amaurobius ferox, Tegenaria atrica and Malthonica ferruginea (1 each). Clinical presentation was generally mild, with the exception of Cheiracanthium punctorium, and patients recovered fully without sequelae. In Switzerland, spider bites generally have a benign clinical course, which is characterised by minor effects, with rapid and complete recovery. Since only verified spider bites can be regarded as spider bites, in the case of clinically important arachnidism, the spider should be sent to an expert for identification. Our study may help to diminish spider fear and reassure people who have experienced a bite.

  19. ANALYSIS ON THE DYNAMICS OF SPATIAL DISTRIBUTION PATTERN OF MIXED SPIDER POPULATION IN RICE FIELD

    Institute of Scientific and Technical Information of China (English)

    ZhiWang; Zhe-mingYuan; Da-xiangSong; Ming-shengZhu

    2004-01-01

    The results make it clear that there are total 11 families, 29 genera and 43 species of spiders in the rice field of Dong Fang Hong Farm. Among them, there are 8 families, 19 genera and 28 species in the early rice field, and 10 families, 27 genera and 36 species in the late rice field. The spatial distribution pattern of mixed spider populations in rice fields was different during different development stages of rice plant. During the prophase, metaphase and anaphase of early rice plant development, the spatial distribution pattern of mixed spider populations was aggregative, random and aggregative respectively. During the prophase, metaphase and anaphase of late rice plant development, the spatial distribution pattern was uniform, aggregative and uniform respectively.

  20. A golden-silk spider spins its web

    Science.gov (United States)

    1999-01-01

    On the grounds of Kennedy Space Center, a female Golden-Silk Spider repairs its web. The female can be identified by its brownish-green abdomen with a white spotted irregular pattern. The golden-silk spider repairs the webbing each day, replacing half but never the whole web at one time. Its web may measure two to three feet across. The center shares a boundary with the Merritt Island National Wildlife Refuge, a 92,000-acre refuge that is a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  1. A golden-silk spider spins its web

    Science.gov (United States)

    1999-01-01

    On the grounds of Kennedy Space Center, a female Golden-Silk Spider repairs its web. The female can be identified by its brownish-green abdomen with a white spotted irregular pattern. The golden-silk spider repairs the webbing each day, replacing half but never the whole web at one time. Its web may measure two to three feet across. The center shares a boundary with the Merritt Island National Wildlife Refuge, a 92,000-acre refuge that is a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  2. Brown spider (Loxosceles genus) venom toxins: tools for biological purposes.

    Science.gov (United States)

    Chaim, Olga Meiri; Trevisan-Silva, Dilza; Chaves-Moreira, Daniele; Wille, Ana Carolina M; Ferrer, Valéria Pereira; Matsubara, Fernando Hitomi; Mangili, Oldemir Carlos; da Silveira, Rafael Bertoni; Gremski, Luiza Helena; Gremski, Waldemiro; Senff-Ribeiro, Andrea; Veiga, Silvio Sanches

    2011-03-01

    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.

  3. 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.

  4. [The "hornet spider" of Plinius].

    Science.gov (United States)

    Moog, Ferdinand Peter

    2002-01-01

    Pliny the Elder describes in his 'Natural History' XXIX 86 a species of spider dangerous for human beings and looking like a hornet without wings. This description corresponds to Solipugae of the genus Karschia, living in arid areas of Central Asia. These animals are not venomous but can cause harm by their powerful bite and in some cases by a following inflammation of the wound. On the contrary, an animal called "wasp-like", mentioned by Nikander of Kolophon ('Theriaca', v. 738-746) and often regarded to be the same creature, seems to be a typical venomous spider which causes an acute intoxication by its bite.

  5. What's on the therapist's mind? A grounded theory analysis of family therapist reflections during individual therapy sessions.

    Science.gov (United States)

    Rober, Peter; Elliott, Robert; Buysse, Ann; Loots, Gerrit; De Corte, Kim

    2008-01-01

    The authors used a videotape-assisted recall procedure to study the content of family therapists' inner conversations during individual sessions with a standardized client. Grounded theory was used to analyze therapists' reflections, resulting in a taxonomy of 282 different codes in a hierarchical tree structure of six levels, organized into four general domains: attending to client process; processing the client's story; focusing on therapists' own experience; and managing the therapeutic process. In addition to providing a descriptive model of therapists' inner conversation, this research led to an appreciation of the wealth of therapists' inner conversation. In particular, the authors found that therapists work hard to create an intersubjective space within which to talk by trying to be in tune with their clients and by using clients as a guide.

  6. ANTHROPOLOGICAL-BIOLOGICAL GROUNDS OF FAMILY AND MARRIAGE STRATEGIES ILLUSTRATED BY POLYANDRY AND GENDER

    Directory of Open Access Journals (Sweden)

    Rustam Karimovich Akhmedov

    2015-01-01

    Full Text Available In the article, the author makes an attempt of philosophical understanding of gender issues by establishing a connection between human habitat and social gender, which determines human behavior. Archaic polyandrous societies are analyzed through the prism of ethology and biology in order to find identical reasons for the emergence of polyandry, its types and general patterns of development of gender models. Based on the study of these societies, the author comes to the conclusion: the influence of the abundance of food resources on the strategies of family and marriage relations is quite significant; the variety of gender models in polyandric societies is limited and has clear genetic and ecological preconditions. In addition, as a result of the study, the author makes the hypothesis about the further gender development: the probability of leveling the social genders in today's world is extremely low due to the absence of natural selection, which could assist to leveling the corresponding genetic predispositions.

  7. A Proteomics and Transcriptomics Investigation of the Venom from the Barychelid Spider Trittame loki (Brush-Foot Trapdoor

    Directory of Open Access Journals (Sweden)

    Eivind A. B. Undheim

    2013-12-01

    Full Text Available Although known for their potent venom and ability to prey upon both invertebrate and vertebrate species, the Barychelidae spider family has been entirely neglected by toxinologists. In striking contrast, the sister family Theraphosidae (commonly known as tarantulas, which last shared a most recent common ancestor with Barychelidae over 200 million years ago, has received much attention, accounting for 25% of all the described spider toxins while representing only 2% of all spider species. In this study, we evaluated for the first time the venom arsenal of a barychelid spider, Trittame loki, using transcriptomic, proteomic, and bioinformatic methods. The venom was revealed to be dominated by extremely diverse inhibitor cystine knot (ICK/knottin peptides, accounting for 42 of the 46 full-length toxin precursors recovered in the transcriptomic sequencing. In addition to documenting differential rates of evolution adopted by different ICK/knottin toxin lineages, we discovered homologues with completely novel cysteine skeletal architecture. Moreover, acetylcholinesterase and neprilysin were revealed for the first time as part of the spider-venom arsenal and CAP (CRiSP/Allergen/PR-1 were identified for the first time in mygalomorph spider venoms. These results not only highlight the extent of venom diversification in this neglected ancient spider lineage, but also reinforce the idea that unique venomous lineages are rich pools of novel biomolecules that may have significant applied uses as therapeutics and/or insecticides.

  8. A proteomics and transcriptomics investigation of the venom from the barychelid spider Trittame loki (brush-foot trapdoor).

    Science.gov (United States)

    Undheim, Eivind A B; Sunagar, Kartik; Herzig, Volker; Kely, Laurence; Low, Dolyce H W; Jackson, Timothy N W; Jones, Alun; Kurniawan, Nyoman; King, Glenn F; Ali, Syed A; Antunes, Agostino; Ruder, Tim; Fry, Bryan G

    2013-12-13

    Although known for their potent venom and ability to prey upon both invertebrate and vertebrate species, the Barychelidae spider family has been entirely neglected by toxinologists. In striking contrast, the sister family Theraphosidae (commonly known as tarantulas), which last shared a most recent common ancestor with Barychelidae over 200 million years ago, has received much attention, accounting for 25% of all the described spider toxins while representing only 2% of all spider species. In this study, we evaluated for the first time the venom arsenal of a barychelid spider, Trittame loki, using transcriptomic, proteomic, and bioinformatic methods. The venom was revealed to be dominated by extremely diverse inhibitor cystine knot (ICK)/knottin peptides, accounting for 42 of the 46 full-length toxin precursors recovered in the transcriptomic sequencing. In addition to documenting differential rates of evolution adopted by different ICK/knottin toxin lineages, we discovered homologues with completely novel cysteine skeletal architecture. Moreover, acetylcholinesterase and neprilysin were revealed for the first time as part of the spider-venom arsenal and CAP (CRiSP/Allergen/PR-1) were identified for the first time in mygalomorph spider venoms. These results not only highlight the extent of venom diversification in this neglected ancient spider lineage, but also reinforce the idea that unique venomous lineages are rich pools of novel biomolecules that may have significant applied uses as therapeutics and/or insecticides.

  9. An orb-weaver spider exploits an ant-acacia mutualism for enemy-free space.

    Science.gov (United States)

    Styrsky, John D

    2014-02-01

    Exploiters of protection mutualisms are assumed to represent an important threat for the stability of those mutualisms, but empirical evidence for the commonness or relevance of exploiters is limited. Here, I describe results from a manipulative study showing that an orb-weaver spider, Eustala oblonga, inhabits an ant-acacia for protection from predators. This spider is unique in the orb-weaver family in that it associates closely with both a specific host plant and ants. I tested the protective effect of acacia ants on E. oblonga by comparing spider abundance over time on acacias with ants and on acacias from which entire ant colonies were experimentally removed. Both juvenile and adult spider abundance significantly decreased over time on acacias without ants. Concomitantly, the combined abundance of potential spider predators increased over time on acacias without ants. These results suggest that ant protection of the ant-acacia Acacia melanocerus also protects the spiders, thus supporting the hypothesis that E. oblonga exploits the ant-acacia mutualism for enemy-free space. Although E. oblonga takes advantage of the protection services of ants, it likely exacts little to no cost and should not threaten the stability of the ant-acacia mutualism. Indeed, the potential threat of exploiter species to protection mutualisms in general may be limited to species that exploit the material rewards traded in such mutualisms rather than the protection services.

  10. Refractive index measurements of double-cylinder structures found in natural spider silks

    Science.gov (United States)

    Little, Douglas J.; Kane, Deb M.

    2014-05-01

    The silks of Orb-Weaver spiders (family Araneidae) are emerging as fascinating optical materials due to their biocompatibility, ecological sustainability and mechanical robustness. Natural spider silks are mainly spun as double cylinders, with diameters ranging from 0.05 to 10 μm, depending on the species and maturity of the spider. This small size makes the silks difficult to characterize optically with traditional techniques. Here, we present a technique that is capable of measuring both the real and imaginary refractive index components of spider silks. This technique is also a new capability for characterizing micro-optics more generally. It is based on the measurement and analysis of refracted light through the spider silk, or micro-optic, while it is immersed in a liquid of known refractive index. It can be applied at any visible wavelength. Results at 540 nm are reported. Real refractive indices in the range of 1.54-1.58 were measured, consistent with previous studies of spider silks. Large silk-to-silk variability of the p-polarized refractive index was observed of around 0.015, while variability in the s-polarized refractive index was negligible. No discernible difference in the refractive indices of the two cylinders making up the double cylinder silk structure were observed. Measured imaginary refractive indices corresponded to an optical loss of around 14 dB/mm at 540 nm.

  11. 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.

  12. A check list of the spider fauna of the Karoo National Park, South Africa (Arachnida: Araneae

    Directory of Open Access Journals (Sweden)

    Anna S. Dippenaar-Schoeman

    1999-01-01

    Full Text Available A check list of the spider species of the Karoo National Park collected over a period of 10 years is presented. Thirty-eight families, represented by 102 genera and 116 species have been collected. Of these species, 76 (66.4 were wanderers and 39 (33.6 web builders. The Araneidae have the highest number of species (14 followed by the Thomisidae (10 and the Gnaphosidae (8, while 14 families are represented by a single species. Information on spider guilds, their habitat preference and web types is provided. This study forms part of the South African National Survey of Arachnida (SANSA.

  13. Spiders of soybean crops in Santa Fe province, Argentina: influence of surrounding spontaneous vegetation on lot colonization.

    Science.gov (United States)

    Beltramo, J; Bertolaccini, I; González, A

    2006-08-01

    Trials during two consecutive soybean cycles were performed in central Santa Fe in order to determine the main spider families present in the crop and to determine the influence of spontaneous margin flora on colonization towards the lot. Samplings were done by sweeping net and pitfall traps. It was concluded that:1. Oxyopidae was the most frequent family in the herbaceous layer of both the margins and the soybean crop, and Lycosidae in the lower layer; 2. Margin strips in a soybean lot contribute to the colonization of the crop by spiders of aerial habits and also promote re-colonization following pesticide applications, since they act as shelters. The influence on spiders of terrestrial habits was somewhat lower; 3. The distribution of the populations of spiders of terrestrial habits was homogeneous in a soybean crop seeded directly and these predators had a greater capacity to control pests at all points of the lot.

  14. Spider silk: Webs measure up

    Science.gov (United States)

    Qin, Zhao; Buehler, Markus J.

    2013-03-01

    The complete elastic response of a spider's orb web has been quantified by non-invasive light scattering, revealing important insights into the architecture, natural material use and mechanical properties of the web. This knowledge advances our understanding of the prey-catching process and the role of supercontraction therein.

  15. 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…

  16. Epigeic spiders of the pastures of northern Wielkopolska

    Directory of Open Access Journals (Sweden)

    Woźny, Marek

    2000-10-01

    Full Text Available The fauna of epigeic spiders (Araneae occurring on three different types of pastures in northern Wielkopolska was analysed. Studies were conducted from May 1992 to October 1993. The 18,995 specimens collected were classified as belonging to 137 species and 17 families. The family Linyphiidae proved the richest in species while Lycosidae was the most abundantly in terms of number of specimens. Zoocenological analysis of spider communities showed their differentiation testifying to differences in the sites studied. The dominants were: 1 Osowo Stare (Site 1: Pardosa palustris, 2 Sycyn Dolny (Site 2: Xerolycosa miniata, P. palustris, Xysticus kochi, 3 Braczewo (Site 3: Erigone dentipalpis, P. palustris. Seasonal changes of dominance of the species at each site were established. A comparison of changes of the species’ dominances in the years 1992 and 1993 disclosed similar values of the individual dominance coefficient at the sites in Osowo Stare and Braczewo. This result indicates the occurrence of the process of stabilization of these biocenoses and a tendency to equilibrium in the environment. The least stable proved to be the site at Sycyn Dolny. Analysis of the seasonal dynamics of epigeic spider communities was also made by determining the mean number of species at each site in the two years of study. The highest number of species was noted in spring. It is interesting to note the appearance of species which are rare or very rare in Poland such as: Lepthyphantes insignis, Ostearius melanopygius, Enoplognatha mordax and Enoplognatha oelandica.

  17. Peptidomic and transcriptomic profiling of four distinct spider venoms.

    Science.gov (United States)

    Oldrati, Vera; Koua, Dominique; Allard, Pierre-Marie; Hulo, Nicolas; Arrell, Miriam; Nentwig, Wolfgang; Lisacek, Frédérique; Wolfender, Jean-Luc; Kuhn-Nentwig, Lucia; Stöcklin, Reto

    2017-01-01

    Venom based research is exploited to find novel candidates for the development of innovative pharmacological tools, drug candidates and new ingredients for cosmetic and agrochemical industries. Moreover, venomics, as a well-established approach in systems biology, helps to elucidate the genetic mechanisms of the production of such a great molecular biodiversity. Today the advances made in the proteomics, transcriptomics and bioinformatics fields, favor venomics, allowing the in depth study of complex matrices and the elucidation even of minor compounds present in minute biological samples. The present study illustrates a rapid and efficient method developed for the elucidation of venom composition based on NextGen mRNA sequencing of venom glands and LC-MS/MS venom proteome profiling. The analysis of the comprehensive data obtained was focused on cysteine rich peptide toxins from four spider species originating from phylogenetically distant families for comparison purposes. The studied species were Heteropoda davidbowie (Sparassidae), Poecilotheria formosa (Theraphosidae), Viridasius fasciatus (Viridasiidae) and Latrodectus mactans (Theridiidae). This led to a high resolution profiling of 284 characterized cysteine rich peptides, 111 of which belong to the Inhibitor Cysteine Knot (ICK) structural motif. The analysis of H. davidbowie venom revealed a high richness in term of venom diversity: 95 peptide sequences were identified; out of these, 32 peptides presented the ICK structural motif and could be classified in six distinct families. The profiling of P. formosa venom highlighted the presence of 126 peptide sequences, with 52 ICK toxins belonging to three structural distinct families. V. fasciatus venom was shown to contain 49 peptide sequences, out of which 22 presented the ICK structural motif and were attributed to five families. The venom of L. mactans, until now studied for its large neurotoxins (Latrotoxins), revealed the presence of 14 cysteine rich

  18. Systematics, phylogeny, and evolution of orb-weaving spiders.

    Science.gov (United States)

    Hormiga, Gustavo; Griswold, Charles E

    2014-01-01

    The orb-weaving spiders (Orbiculariae) comprise more than 25% of the approximately 44,000 known living spider species and produce a remarkable variety of webs. The wheel-shaped orb web is primitive to this clade, but most Orbiculariae make webs hardly recognizable as orbs. Orb-weavers date at least to the Jurassic. With no evidence for convergence of the orb web, the monophyly of the two typical orb web taxa, the cribellate Deinopoidea and ecribellate Araneoidea, remains problematic, supported only weakly by molecular studies. The sister group of the Orbiculariae also remains elusive. Despite more than 15 years of phylogenetic scrutiny, a fully resolved cladogram of the Orbiculariae families is not yet possible. More comprehensive taxon sampling, comparative morphology, and new molecular markers are required for a better understanding of orb-weaver evolution.

  19. A Spider That Lays Its Eggs in Rows

    Directory of Open Access Journals (Sweden)

    Robert L. Edwards

    2000-01-01

    Full Text Available The small (2.5-3.0 mm, colorful metine spider, Homalometa nigritarsis Simon 1897, Family Tetragnathidae, has previously been reported from northern Mexico, Panama and the southern islands of the Lesser Antilles (Levi 1986. In the rain forest of northeastern Puerto Rico it is most frequently found with webbing on the larger outer concave surfaces of pendulous leaves. H. nigritarsis typically makes a circular, relatively flat retreat within which the female deposits two parallel rows of naked eggs. The rows are produced at intervals; as one row hatches another replaces it shortly thereafter. Evidence of up to four generations of rows has been observed. Above the retreat, and closely aligned with it, the spider builds a nearly invisible, delicate orb web, typically from edge to edge of the leaf (Fig. 1a and b. While retaining the traditional orb-web, H. nigritarsis has adopted a unique habitat and set of life history features.

  20. The Legs That Rock the Cradle: Spider Mothers

    Indian Academy of Sciences (India)

    Vinayak Patil

    2017-05-01

    Spiders are excellent models to study behavioural diversityand evolutionary adaptations in the animal world. This articleexplores the strategies used by spiders to maximise thesurvival of their offspring.

  1. Epidemiology of the brown recluse spider bite.

    Science.gov (United States)

    Rhoads, Jacqueline

    2007-02-01

    The purpose of this article was to provide a comprehensive epidemiological and clinical description of the brown recluse spider bite. Review of evidenced-based scientific literature and practice guidelines. A specific descriptive case study is interwoven through the article to tie in the clinical presenting figure associated with this bite. The brown recluse lives in a circumscribed area of the United States (the south central Midwest) with a few less common recluse species living in the more sparsely populated southwest United States. In these areas, where spider populations may be dense, recluse spiders may be a cause of significant morbidity. Most spider bites are asymptomatic but what makes this bite so devastating is the toxin injected by the brown recluse spider, which can cause considerable systemic symptoms as well as necrotic skin ulcers (necrotic arachnidism). The article presents process for diagnosis and stresses the importance of identifying the spider if at all possible.

  2. The evolution of sociality in spiders

    DEFF Research Database (Denmark)

    Lubin, Yael; Bilde, T.

    2007-01-01

    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....... 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...

  3. Production of Synthetic Spider Silk Fibers

    OpenAIRE

    Copeland, Cameron G.

    2016-01-01

    Orb-weaving spiders produce six different types of silks, each with unique mechanical properties. The mechanical properties of many of these silks, in particular the dragline silk, are of interest for various biomedical applications. Spider silk does not elicit an immune response, making it an ideal material for several applications in the medical field. However, spiders cannot be farmed for their silk as they are cannibalistic and territorial. The most reasonable alternative for producing sp...

  4. Designing Spider Silk Proteins for Materials Applications

    Science.gov (United States)

    2009-10-28

    WY, 82071-3944 Agreement Number: FA9550-06-1-0368 Project Title: Designing Spider Silk Proteins for Materials Applications REPORT...From - To) 06/2006-010/2009 4. TITLE AND SUBTITLE Designing Spider Silk Proteins for Materials Applications 5a. CONTRACT NUMBER 5b...AVAILABILITY STATEMENT Approved for public release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Spider silks have the

  5. SPIDERS (ARANEI IN HEPRETOBIONT MESOFAUNA OF THE NORTHWEST CAUCASUS

    Directory of Open Access Journals (Sweden)

    A. V. Ponomarev

    2014-01-01

    Full Text Available Abstract. Aim. We discussed in previous work a herpetobiont fauna of arachnids (Arachnida from the isolated yewboxwood wood, located in the Caucasian State Biosphere Reserve, 20 km near Sochi (Ponomarev, Chumachenko, 2007. The aim of the paper is to summarize available data about herpetobiont araneofauna of the Northwest Caucasus. Location. Republic of Adygea, Russia.Methods. Material was collected in 2009 on north macroslope of Main Caucasian Ridge within the territory of the Caucasian State Biosphere Reserve between 1000–1820 m. The following plant communities are studied: beech-silver fir (assotiation Abieti-Fagetion orientalis Korotkov et Belonovskaya 1987, maple forest (assotiation Petasito albae-Abietetum nordmannianae subassotiation Aceretosum trautvetteri Francuzov 2006, subalpine meadow (assotiation Poa longifolii – Calamagrostietum arundinaceae Semagina, 1992. Soil traps were used for collection of spiders.Results and main conclusions. During the period of study 100 species of spiders from 19 families are registered. Most diverse araneofauna of subalpine meadows includs 54 species belonging to 14 families. The least diverse araneofauna is in maple forest (24 species of 7 families. In beech-silver fir includes 45 species of 16 families of spiders. Only 3 species (Pireneitega ovtchinnikovi, Cybaeus abchasicus, Tenuiphantes mengei were found in all surveyed habitats. These 3 species clearly tend to forest habitats. Herpetobiont araneofauna of the Northwest Caucasus characterized by high taxonomic diversity with clear predominance of representatives of the family Linyphiidae. Specificity of araneofauna in different types of plant communities is high.

  6. Structure to function: Spider silk and human collagen

    Science.gov (United States)

    Rabotyagova, Olena S.

    Nature has the ability to assemble a variety of simple molecules into complex functional structures with diverse properties. Collagens, silks and muscles fibers are some examples of fibrous proteins with self-assembling properties. One of the great challenges facing Science is to mimic these designs in Nature to find a way to construct molecules that are capable of organizing into functional supra-structures by self-assembly. In order to do so, a construction kit consisting of molecular building blocks along with a complete understanding on how to form functional materials is required. In this current research, the focus is on spider silk and collagen as fibrous protein-based biopolymers that can shed light on how to generate nanostructures through the complex process of self-assembly. Spider silk in fiber form offers a unique combination of high elasticity, toughness, and mechanical strength, along with biological compatibility and biodegrability. Spider silk is an example of a natural block copolymer, in which hydrophobic and hydrophilic blocks are linked together generating polymers that organize into functional materials with extraordinary properties. Since silks resemble synthetic block copolymer systems, we adopted the principles of block copolymer design from the synthetic polymer literature to build block copolymers based on spider silk sequences. Moreover, we consider spider silk to be an important model with which to study the relationships between structure and properties in our system. Thus, the first part of this work was dedicated to a novel family of spider silk block copolymers, where we generated a new family of functional spider silk-like block copolymers through recombinant DNA technology. To provide fundamental insight into relationships between peptide primary sequence, block composition, and block length and observed morphological and structural features, we used these bioengineered spider silk block copolymers to study secondary structure

  7. Adhesive foot pads: an adaptation to climbing? An ecological survey in hunting spiders.

    Science.gov (United States)

    Wolff, Jonas O; Gorb, Stanislav N

    2015-02-01

    Hairy pads relying on dry adhesion are fascinating structures that convergently evolved among spiders and lizards. Numerous studies underline the functional aspects leading to their strong adhesion to smooth surfaces, but rarely has their role been studied in the context of natural habitats and surfaces that animals are faced with. In hunting spiders, the hairy foot pads (claw tufts) underneath the paired claws are assumed to be an adaptation to a climbing lifestyle, particularly on smooth plant surfaces. However, surfaces that are too smooth for claws to generate a sufficient grip are rather rare in natural habitats and above-ground habitats are occupied by hunting spiders both with and without claw tufts. In this study we estimated the proportion of claw tuft-bearing hunting spiders (ct+ ratio) among microhabitat-specific assemblages by conducting both a field study and a meta-analysis approach. The effect of surface characteristics, structure fragmentation and altitude of the microhabitat niche on the ct+ ratio was analyzed. We hypothesized that the ct+ ratio will be higher in (i) hunting spider assemblages obtained from microhabitats above the ground than from those at the ground and (ii) in hunting spider assemblages obtained from microhabitats with smoother surfaces (tree foliage) than those with rougher surfaces (barks, stones), and lower in (iii) hunting spider assemblages obtained from microhabitats with more fragmented structures (small leaves) than in those with comparable but less fragmented structures (large leaves). We found the ct+ ratio to be significantly affected by the microhabitat's distance from the ground, whereas surface characteristics and fragmentation of the substrates were of minor importance. This suggests that claw tufts are highly beneficial when the microhabitat's height exceeds a value where the additional pad-related costs are exceeded by the costs of dropping. We assume the benefit to be mainly due to gaining a high safety factor

  8. Carbon nanotubes on a spider silk scaffold

    Science.gov (United States)

    Steven, Eden; Saleh, Wasan R.; Lebedev, Victor; Acquah, Steve F. A.; Laukhin, Vladimir; Alamo, Rufina G.; Brooks, James S.

    2013-09-01

    Understanding the compatibility between spider silk and conducting materials is essential to advance the use of spider silk in electronic applications. Spider silk is tough, but becomes soft when exposed to water. Here we report a strong affinity of amine-functionalised multi-walled carbon nanotubes for spider silk, with coating assisted by a water and mechanical shear method. The nanotubes adhere uniformly and bond to the silk fibre surface to produce tough, custom-shaped, flexible and electrically conducting fibres after drying and contraction. The conductivity of coated silk fibres is reversibly sensitive to strain and humidity, leading to proof-of-concept sensor and actuator demonstrations.

  9. Decoding the secrets of spider silk

    Directory of Open Access Journals (Sweden)

    Lukas Eisoldt

    2011-03-01

    Full Text Available Spider silks have been employed by man for several thousands of years. Spider silks possess extraordinary mechanical properties due to a combination of strength and extensibility that are superior to most man-made fibers. Spider silk fibers are a protein-based material produced in a highly sophisticated hierarchical process under mild conditions. Here, we review the current understanding of spider silk and its assembly process, as well as discuss the application of silk-based materials to the fields of biomedicine and materials engineering.

  10. Phylogeny of pholcid spiders (Araneae: Pholcidae): combined analysis using morphology and molecules.

    Science.gov (United States)

    Bruvo-Madarić, Branka; Huber, Bernhard A; Steinacher, Arno; Pass, Günther

    2005-12-01

    The spider family Pholcidae comprises a large number of mainly tropical, web-weaving spiders, and is among the most diverse and dominant spider groups in the world. The phylogeny of this family has so far been investigated exclusively using morphological data. Here, we present the first molecular data for the family analyzed in a phylogenetic context. Four different gene regions (12S rRNA, 16S rRNA, cytochrome c oxidase subunit I, 28S rRNA) and 45 morphological characters were scored for 31 pholcid and three outgroup taxa. The data were analyzed both for individual genes, combined molecular data, and molecular plus morphological data, using parsimony, maximum likelihood, and Bayesian methods. Some of the phylogenetic hypotheses obtained previously using morphology alone were also supported by our results, like the monophyly of pholcines and of the New World clade. On the other hand, some of the previous hypotheses could be discarded with some confidence (monophyly of holocnemines, the position of Priscula), and still others need further investigation (the position of holocnemines, ninetines, and Metagonia). The data obtained provide an excellent basis for future investigations of phylogenetic patterns both within the family and among spider families.

  11. SPIDER DIVERSITY (ARACHNIDA: ARANEAE OF THE TEA PLANTATION AT SERANG VILLAGE, KARANGREJA SUB-DISTRICT, DISTRICT OF PURBALINGGA

    Directory of Open Access Journals (Sweden)

    Gianti Sibarani

    2017-06-01

    Full Text Available Spiders are crucial in controlling insect pest population. The various cultivation managements such as fertilizer and pesticide application, weeding, pruning, harvesting, and cropping system affect their diversity. In the plantation, vegetation diversification has applied various practices, including monoculture, and intercropping, which influence the spider community. Thus, this study was intended to determine the spider abundance and diversity of the tea plantation, and the intercropping field (tea and strawberry at Serang village, Karangreja Sub-District, District of Purbalingga. A survey and purposive sampling techniques were conducted, then the spiders were hand collected. Shannon-Wiener diversity (H’, Evenness (E, Simpson’s dominance (D, and Sorensen’s similarity (IS indices were used to measure the spider diversity. The results revealed a total number of 575 individual spiders from 10 families, i.e., Araneae, Araneidae, Clubionidae, Linyphiidae, Lycosidae, Nephilidae, Oxyopidae, Salticidae, Tetragnathidae, Theridiidae, and Thomisidae. Araneidae was the most abundant in both fields. The total abundance of spiders in tea plantation (379 individuals, however, was greater than that in the intercropping field (196 individuals. Shannon-Wiener diversity reached H’= 1.873 in the plantation, and H’= 1.975 in the intercropping field.

  12. Abundance and Fluctuation in Spider Diversity in Citrus Fruits from Located in Vicinity of Faisalabad Pakistan

    Institute of Scientific and Technical Information of China (English)

    Maqsood I; Mohsin S B; Li Yi-jing; Tang Li-jie; Saleem K M; Khalil U R; Shahla A; Aoun Bukhari; S S Jamal

    2016-01-01

    Spiders for the present study were collected from different fruit gardens (i.e. citrus) located at various localities (i.e., Tehsil Samundri, Jaranwala, Tandlianwala and Faisalabad) of District Faisalabad, Pakistan. Spiders belonging to six families and 33 species were captured from the two fruit gardens during the one year of this study. The citrus fruits garden was found to be best populated habitat as compared to other fruit garden. These sites were sampled by using pitfall traps; each month for five consecutive days from September 2010 to March 2011. As a result, 1 054 specimens were captured representing six families viz: lycosidae, thomosidae, gnaphosidae, saltisidae, araneidae and clubionidae. Lycosidae was more abundant, while clubionidae was less diverse during the study. Maximum population fluctuation among the spider specimens showed during the months from September and October, while the least abundance of spider specimens was reordered during June, November and December. Maximum taxonomic diversity was recorded from September to November, with the peak in September. It was concluded during these three months, when the citrus and guava gardens were attacked by the most of the pest insects. During the months of July and November diversity was moderate and mutually comparable, while in June and December, it was the least. This study contributed to the identification of spider diversity in the agro-ecosystem which could be used in the biological pest control.

  13. Untangling spider silk evolution with spidroin terminal domains

    Directory of Open Access Journals (Sweden)

    Garb Jessica E

    2010-08-01

    Full Text Available Abstract Background Spidroins are a unique family of large, structural proteins that make up the bulk of spider silk fibers. Due to the highly variable nature of their repetitive sequences, spidroin evolutionary relationships have principally been determined from their non-repetitive carboxy (C-terminal domains, though they offer limited character data. The few known spidroin amino (N-terminal domains have been difficult to obtain, but potentially contain critical phylogenetic information for reconstructing the diversification of spider silks. Here we used silk gland expression data (ESTs from highly divergent species to evaluate the functional significance and phylogenetic utility of spidroin N-terminal domains. Results We report 11 additional spidroin N-termini found by sequencing ~1,900 silk gland cDNAs from nine spider species that shared a common ancestor > 240 million years ago. In contrast to their hyper-variable repetitive regions, spidroin N-terminal domains have retained striking similarities in sequence identity, predicted secondary structure, and hydrophobicity. Through separate and combined phylogenetic analyses of N-terminal domains and their corresponding C-termini, we find that combined analysis produces the most resolved trees and that N-termini contribute more support and less conflict than the C-termini. These analyses show that paralogs largely group by silk gland type, except for the major ampullate spidroins. Moreover, spidroin structural motifs associated with superior tensile strength arose early in the history of this gene family, whereas a motif conferring greater extensibility convergently evolved in two distantly related paralogs. Conclusions A non-repetitive N-terminal domain appears to be a universal attribute of spidroin proteins, likely retained from the origin of spider silk production. Since this time, spidroin N-termini have maintained several features, consistent with this domain playing a key role in silk

  14. Desiccation resistance reflects patterns of microhabitat choice in a Central American assemblage of wandering spiders.

    Science.gov (United States)

    Lapinski, Witold; Tschapka, Marco

    2014-08-01

    The lowland rainforest of northeastern Costa Rica harbours an assemblage of large wandering spider species belonging to three habitat subguilds: (1) semi-aquatic, (2) forest ground dwelling and (3) vegetation dwelling. We hypothesized that desiccation resistance should differ among species preferring different microhabitats and the associated microclimate. Desiccation resistance was assessed by: (1) measuring water loss rates of the spiders under relatively dry experimental conditions, and (2) recording desiccation susceptibility, i.e. the reactions of the spiders to a relatively dry environment. High water loss rates and desiccation susceptibility of the semi-aquatic and forest-ground-dwelling subguilds clearly mirrored the relatively humid microclimate of the understory. Significantly lower water loss rates and desiccation susceptibility of the vegetation-dwelling species reflected the highly variable, often dry and hot conditions of the rainforest canopy and forest edge habitats. Vegetation-dwelling wandering spiders are therefore physiologically better adapted to dry conditions than the semi-aquatic and forest-ground-dwelling species. The results illustrate the significance of physiological characteristics for explaining both species-specific habitat use and, in a larger context, niche partitioning within a community.

  15. Structure and Dynamic Analysis of Spider Population of Tea Garden in Taishan Region%泰山茶园蜘蛛种类调查及优势种动态分析

    Institute of Scientific and Technical Information of China (English)

    李巍巍; 刘玉; 张丽霞; 杨超

    2012-01-01

    In the investigation of tea garden in Taishan region, 1095 individual spiders were collected and identified as 13 families and 40 species, which 77.90% of them belong to the group which active on the ground and 21.91% belong to the making web group. Four types of spider species including Pardosa astrigera, Trochosa suiningensis, Anahita fauna and Coelotes taishanensis were the doninant spiders in Taishan tea garden, and showed different dynamic changes in a year. Spiders of Taishan tea garden are active in all the year, the numbers are least in February, most in August and maintain high level during the period of June to September.%通过对泰山茶园进行定点定期调查,共采集蜘蛛1095头,经鉴定隶属13个科40个种,其中以游猎型类群最多,占蜘蛛总量的77.90%,结网型类群占21.91%.星豹蛛、遂宁獾蛛、黄栉足蛛和泰山隙蛛为泰山茶园的优势种,具有不同的年变化动态.泰山茶园全年皆有蜘蛛活动,数量以2月份最少,8月下旬最多,6~9月份维持在较高的水平.

  16. Web placement in sympatric linyphiid spiders ( Arachnida, Araneae): Individual foraging decisions reveal inter-specific competition

    Science.gov (United States)

    Herberstein, Marie Elisabeth

    1998-02-01

    The distribution of two sympatric web spiders, Frontinellina frutetorum (C. L. Koch) and Neriene radiata (Walckenaer) (Araneae: Linyphiidae) was studied on an area of forest regrowth in eastern Austria. Both species utilised significantly different heights on young conifer trees to construct their webs. F. frutetorum selected higher vegetation layers, whereas N. radiata constructed its webs, closer to the ground. This distribution may either be evidence of competition for web space or it may reflect specific distribution patterns unrelated to spider density. An experiment showed that when spiders of either species were released onto vacant trees they selected similar vegetation heights for web construction. On trees already occupied by a heterospecific individual however, F. frutetorum placed its webs significantly higher and N. radiata significantly lower compared to web placement on vacant trees suggesting that F. frutetorum and N. radiata compete for web space.

  17. Heat Capacity of Spider Silk-like Block Copolymers.

    Science.gov (United States)

    Huang, Wenwen; Krishnaji, Sreevidhya; Hu, Xiao; Kaplan, David; Cebe, Peggy

    2011-07-12

    We synthesized and characterized a new family of di-block copolymers based on the amino acid sequences of Nephila clavipes major ampulate dragline spider silk, having the form HABn and HBAn (n=1-3), comprising an alanine-rich hydrophobic block, A, a glycine-rich hydrophilic block, B, and a histidine tag, H. The reversing heat capacities, Cp(T), for temperatures below and above the glass transition, Tg, were measured by temperature modulated differential scanning calorimetry. For the solid state, we then calculated the heat capacities of our novel block copolymers based on the vibrational motions of the constituent poly(amino acid)s, whose heat capacities are known or can be estimated from the ATHAS Data Bank. For the liquid state, the heat capacity was estimated by using the rotational and translational motions in the polymer chain. Excellent agreement was found between the measured and calculated values of the heat capacity, showing that this method can serve as a standard by which to assess the Cp for other biologically inspired block copolymers. The fraction of beta sheet crystallinity of spider silk block copolymers was also determined by using the predicted Cp, and was verified by wide angle X-ray diffraction and Fourier transform infrared spectroscopy. The glass transition temperatures of spider silk block copolymer were fitted by Kwei's equation and the results indicate that attractive interaction exists between the A-block and B-block.

  18. Four new species of the spider genus Nesticella Lehtinen & Saaristo, 1980 from Laos, Thailand and Myanmar and the first description of the male of Nesticella yui Wunderlich & Song, 1995 with a proposed new diagnostic character for the family Nesticidae Simon, 1894 (Arachnida, Araneae).

    Science.gov (United States)

    Grall, Elena; Jäger, Peter

    2016-03-02

    During various expeditions to Laos between 2003 and 2012 and one expedition to Myanmar in 2014, spiders of the family Nesticidae were collected inside and outside of caves. This was the first time this family was encountered in Laos. All specimens belong to the genus Nesticella Lehtinen & Saaristo, 1980. Four species have been recognized as being new to science, which are described in this paper: Nesticella beccus n. sp. (male, female; LAOS: Bolikhamsay Province, Luang Prabang Province, Huaphan Province, Khammouan Province, THAILAND: Mae Hong Son Province), Nesticella laotica n. sp. (male, female; LAOS: Vientiane Province, Huaphan Province, Luang Prabang Province, Bolikhamsay Province), Nesticella foelixi n. sp. (male; LAOS: Bolikhamsay Province) and Nesticella michaliki n. sp. (male, female; MYANMAR: Chin State). The male of Nesticella yui Wunderlich & Song, 1995 is described for the first time and it is the first record for Laos. Results from a first micro-computed tomography analysis of a female copulatory organ for this genus are provided. This analysis proves that female Nesticella exhibit a complex functional receptaculum, which is highly complex within the genus. The presence of a special type of leg setae (pipette setae) in males is proposed as diagnostic for the family Nesticidae.

  19. Annotated Check List of the Spiders (Araneae of the Mountain Zebra National Park

    Directory of Open Access Journals (Sweden)

    Anna S. Dippenaar-Schoeman

    1988-10-01

    Full Text Available A preliminary check list of the spider fauna of the Mountain Zebra National Park is given. Sixteen families, comprising 29 genera and 32 species, are recorded. Observations on the distribution, diagnostic morphology and behaviour of 15 species are given.

  20. Eocene and not Cretaceous origin of spider wasps: Fossil evidence from amber

    Directory of Open Access Journals (Sweden)

    Juanita Rodriguez

    2016-02-01

    Full Text Available Spider wasps had long been proposed to originate in the mid-Cretaceous based on the Burmese amber fossil Bryopompilus interfector Engel and Grimaldi, 2006. We performed a morphological examination of this fossil and determined it does not belong to Pompilidae or any other described hymenopteran family. Instead, we place it in the new family Bryopompilidae. The oldest verifiable member of the Pompilidae is from Baltic amber, which suggests the family probably originated in the Eocene, not in the mid-Cretaceous as previously proposed. The origin of spider wasps appears to be correlated with an increase in spider familial diversity in the Cenozoic. We also we add two genera to the extinct pompilid fauna: Tainopompilus gen. nov., and Paleogenia gen. nov., and describe three new species of fossil spider wasps: Anoplius planeta sp. nov., from Dominican amber (Burdigalian to Langhian; Paleogenia wahisi sp. nov., from Baltic amber (Lutetian to Priabonian; and Tainopompilus argentum sp. nov, from Dominican amber (Chattian to Langhian.

  1. Palpimanid spiders from Guyana: new species of the genera Fernandezina and Otiothops (Araneae, Palpimanidae, Otiothopinae

    Directory of Open Access Journals (Sweden)

    Grismado Cristian J.

    2002-01-01

    Full Text Available Two new species of the spider family Palpimanidae from Guyana are described: Fernandezina takutu, the first species of this genus known from this country andOtiothops giralunas, that seems to be the sister species of O. goloboffi Grismado, 1996 from northwestern Argentina.

  2. Reproductive Seasonality in Nesticus (Araneae: Nesticidae) Cave Spiders.

    Science.gov (United States)

    Carver, Linnea M; Perlaky, Patricia; Cressler, Alan; Zigler, Kirk S

    2016-01-01

    Spiders of the family Nesticidae are members of cave communities around the world with cave-obligate (troglobiotic) species known from North America, Europe, Asia and the Indo-Pacific. A radiation of Nesticus (Araneae: Nesticidae) in the southern Appalachians includes ten troglobiotic species. Many of these species are of conservation interest due to their small ranges, with four species being single-cave endemics. Despite conservation concerns and their important role as predators in cave communities, we know little about reproduction and feeding in this group. We addressed this knowledge gap by examining populations of two species on a monthly basis for one year. We made further observations on several other species and populations, totaling 671 individual spider observations. This more than doubled the reported observations of reproduction and feeding in troglobiotic Nesticus. Female Nesticus carry egg sacs, facilitating the determination of the timing and frequency of reproduction. We found that Nesticus exhibit reproductive seasonality. Females carried egg sacs from May through October, with a peak in frequency in June. These spiders were rarely observed with prey; only 3.3% (22/671) of individuals were observed with prey items. The frequency at which prey items were observed did not vary by season. Common prey items were flies, beetles and millipedes. Troglobiotic species constituted approximately half of all prey items observed. This result represents a greater proportion of troglobiotic prey than has been reported for various troglophilic spiders. Although our findings shed light on the life history of troglobiotic Nesticus and on their role in cave ecosystems, further work is necessary to support effective conservation planning for many of these rare species.

  3. Early environmental conditions shape personality types in a jumping spider

    Directory of Open Access Journals (Sweden)

    Jannis eLiedtke

    2015-12-01

    Full Text Available Individuals of many species across the animal kingdom are found to be less plastic than expected, even in behavioral traits. The existence of consistent behavioral differences between individuals, termed personality differences, is puzzling, since plastic behavior is considered ideal to enable animals to adaptively respond to changes in environmental conditions. In order to elucidate which mechanisms are important for the evolution of personality differences, it is crucial to understand which aspects of the environment are important for the development of personality differences. Here, we tested whether physical or social aspects of the environment during development influence individual differentiation (mean level of behavior using the jumping spider Marpissa muscosa. Furthermore, we assessed whether those behaviors were repeatable, i.e. whether personalities existed. We applied a split-brood design and raised spider siblings in three different environments: a deprived environment with no enrichment, a socially and a physically enriched environment. We focused on exploratory behavior and repeatedly assessed individual behavior in a novel environment and a novel object test. Results show that the environment during development influenced spiders’ exploratory tendencies: spiders raised in enriched environments tended to be more exploratory. Most investigated behaviors were repeatable (i.e. personalities existed across all individuals tested, whereas only few behaviors were also repeatable across individuals that had experienced the same environmental condition. Taken together, our results indicate that external stimuli can influence the development of one aspect of personality, the inter-individual variation (mean level of behavior, in a jumping spider. We also found family by environment interactions on behavioral traits potentially suggesting genetic variation in developmental plasticity.

  4. The biodiversity and species composition of the spider community of Marion Island, a recent survey (Arachnida: Araneae

    Directory of Open Access Journals (Sweden)

    T.T. Khoza

    2005-12-01

    Full Text Available Marion Island, the larger of the Prince Edward Islands, lies in the sub-Antarctic biogeographic region in the southern Indian Ocean. From previous surveys, four spider species are known from Marion. The last survey was undertaken in 1968. During this study a survey was undertaken over a period of four weeks on the island to determine the present spider diversity and to record information about the habitat preferences and general behaviour of the species present. Three collection methods (active search, Tullgren funnels and pitfall traps were used, and spiders were sampled from six habitat sites. A total of 430 spiders represented by four families were collected, Myro kerguelenesis crozetensis Enderlein, 1909 and M. paucispinosus Berland, 1947 (Desidae, Prinerigone vagans (Audouin, 1826 (Linyphiidae, Cheiracanthium furculatum Karsch, 1879 (Miturgidae and an immature Salticidae. The miturgid and salticid are first records. Neomaso antarticus (Hickman, 1939 (Linyphiidae was absent from samples, confirming that the species might have been an erroneous record.

  5. 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…

  6. Lyriform slit sense organs on the pedipalps and spinnerets of spiders

    Indian Academy of Sciences (India)

    Bhavani Patil; Suphala Prabhu; K P Rajashekhar

    2006-03-01

    Lyriform slits sense organs (LSSO) are a precise assembly of stress detecting cuticular slit sensilla found on the appendages of arachnids. While these structures on the legs of the wandering spider Cupennius salei are well studied in terms of morphology, function and contribution to behaviour, their distribution on pedipalps and spinnerets of spiders is not well explored. A study was therefore carried out to observe the distribution of LSSO on pedipalps and spinnerets of some spider species. Haplogyne spiders belonging to family Pholcidae have a simple complement of LSSOs represented by one or two LSSOs on their femur. The entelegyne spiders possess a complex assembly of LSSOs on the distal segments of their pedipalps. Various types of LSSOs are found on the pedipalps indicating a capacity for analysis of complex cuticular stress. It is suggested that the complexity of LSSOs on pedipalps of entelegyne spiders relates to courtship and spermatophore transfer and may help in reproductive isolation. Lack of LSSOs on the distal segments of pedipalps leads us to infer that unlike legs, pedipalps are less likely to receive vibratory input through their distal segments. Spinnerets have a relatively simple complement of LSSOs. One LSSO is found only on anterior spinnerets and it is a common feature observed among spiders, irrespective of the variations in web building behaviour. The orb-weaving araneid Argiope pulchella, however, has two LSSOs on the anterior spinneret. As non-web builders and orb weavers do not differ markedly in terms of LSSOs on the spinnerets and LSSOs are simple in nature (type A), it is likely that spinning and weaving are not largely regulated by sensory input from LSSOs on the spinnerets.

  7. Lyriform slit sense organs on the pedipalps and spinnerets of spiders.

    Science.gov (United States)

    Patil, Bhavani; Prabhu, Suphala; Rajashekhar, K P

    2006-03-01

    Lyriform slits sense organs (LSSO) are a precise assembly of stress detecting cuticular slit sensilla found on the appendages of arachnids. While these structures on the legs of the wandering spider Cupennius salei are well studied in terms of morphology, function and contribution to behaviour, their distribution on pedipalps and spinnerets of spiders is not well explored. A study was therefore carried out to observe the distribution of LSSO on pedipalps and spinnerets of some spider species. Haplogyne spiders belonging to family Pholcidae have a simple complement of LSSOs represented by one or two LSSOs on their femur. The entelegyne spiders possess a complex assembly of LSSOs on the distal segments of their pedipalps. Various types of LSSOs are found on the pedipalps indicating a capacity for analysis of complex cuticular stress. It is suggested that the complexity of LSSOs on pedipalps of entel-egyne spiders relates to courtship and spermatophore transfer and may help in reproductive isolation. Lack of LSSOs on the distal segments of pedipalps leads us to infer that unlike legs, pedipalps are less likely to receive vibratory input through their distal segments. Spinnerets have a relatively simple complement of LSSOs. One LSSO is found only on anterior spinnerets and it is a common feature observed among spiders, irrespective of the variations in web building behaviour. The orb-weaving araneid Argiope pulchella, however, has two LSSOs on the anterior spinneret. As non-web builders and orb weavers do not differ markedly in terms of LSSOs on the spinnerets and LSSOs are simple in nature (type A), it is likely that spinning and weaving are not largely regulated by sensory input from LSSOs on the spinnerets.

  8. Resting EEG asymmetry and spider phobia

    NARCIS (Netherlands)

    Merckelbach, H; Muris, P; Pool, K; de Jong, Peter

    1998-01-01

    This study examined whether resting EEG asymmetries are related to symptom severity and treatment outcome in spider phobia. Prior to treatment, EEG was recorded in a sample of spider phobic patients (N = 16). Correlations between frontal and parietal asymmetries in alpha power, on the one hand, and

  9. Insects and Spiders. Environmental Education Curriculum.

    Science.gov (United States)

    Topeka Public Schools, KS.

    This unit is designed to provide information on insects and spiders that special education students are capable of understanding. The activities are aimed at level 2 and level 3 educable mentally retarded classes. There are four topics: (1) Characteristics and Life Cycles of Insects; (2) Characteristics of Spiders; (3) Habitats and Food Sources of…

  10. Characterization of Three Venom Peptides from the Spitting Spider Scytodes thoracica

    Science.gov (United States)

    Ariki, Nathanial K.; Muñoz, Lisa E.; Armitage, Elizabeth L.; Goodstein, Francesca R.; George, Kathryn G.; Smith, Vanessa L.; Vetter, Irina; Herzig, Volker; King, Glenn F.; Loening, Nikolaus M.

    2016-01-01

    We present the solution-state NMR structures and preliminary functional characterizations of three venom peptides identified from the spitting spider Scytodes thoracica. Despite little sequence identity to other venom peptides, structural characterization reveals that these peptides contain an inhibitor cystine knot motif common to many venom peptides. These are the first structures for any peptide or protein from spiders of the Scytodidae family. Many venom peptides target neuronal ion channels or receptors. However, we have not been able to determine the target of these Scytodes peptides so we can only state with certainty the channels and receptors that they do not target. PMID:27227898

  11. Characterization of Three Venom Peptides from the Spitting Spider Scytodes thoracica.

    Directory of Open Access Journals (Sweden)

    Nathanial K Ariki

    Full Text Available We present the solution-state NMR structures and preliminary functional characterizations of three venom peptides identified from the spitting spider Scytodes thoracica. Despite little sequence identity to other venom peptides, structural characterization reveals that these peptides contain an inhibitor cystine knot motif common to many venom peptides. These are the first structures for any peptide or protein from spiders of the Scytodidae family. Many venom peptides target neuronal ion channels or receptors. However, we have not been able to determine the target of these Scytodes peptides so we can only state with certainty the channels and receptors that they do not target.

  12. The ecological consequences of temperament in spiders

    Institute of Scientific and Technical Information of China (English)

    Jonathan N.PRUITT; Susan E.RIECHERT

    2012-01-01

    Ecological and evolutionary studies on spiders have been featured prominently throughout the contemporary behavioral syndromes movement.Here we review the behavioral syndromes literature devoted to spiders,and identify some ways in which behavioral syndromes can impact the function of spiders in ecological communities.We further highlight three general themes within the behavioral syndromes literature for which spiders have served as front running model systems:(1) how trait correlations beget performance trade-offs,(2) the influence that behavioral trait variants have on interspecific interactions and (3)mechanisms that aid in maintaining behavioral variation within- and among-populations.Research on behavioral syndromes continues to grow at an impressive rate,and we feel the success of behavioral syndromes studies in spiders bodes well for their continued prominence.

  13. Spider venomics: implications for drug discovery.

    Science.gov (United States)

    Pineda, Sandy S; Undheim, Eivind A B; Rupasinghe, Darshani B; Ikonomopoulou, Maria P; King, Glenn F

    2014-10-01

    Over a period of more than 300 million years, spiders have evolved complex venoms containing an extraordinary array of toxins for prey capture and defense against predators. The major components of most spider venoms are small disulfide-bridged peptides that are highly stable and resistant to proteolytic degradation. Moreover, many of these peptides have high specificity and potency toward molecular targets of therapeutic importance. This unique combination of bioactivity and stability has made spider-venom peptides valuable both as pharmacological tools and as leads for drug development. This review describes recent advances in spider-venom-based drug discovery pipelines. We discuss spider-venom-derived peptides that are currently under investigation for treatment of a diverse range of pathologies including pain, stroke and cancer.

  14. The ecological consequences of temperament in spiders

    Directory of Open Access Journals (Sweden)

    Jonathan N. PRUITT, Susan E. RIECHERT

    2012-08-01

    Full Text Available Ecological and evolutionary studies on spiders have been featured prominently throughout the contemporary behavio­ral syndromes movement. Here we review the behavioral syndromes literature devoted to spiders, and identify some ways in which behavioral syndromes can impact the function of spiders in ecological communities. We further highlight three general themes within the behavioral syndromes literature for which spiders have served as front running model systems: (1 how trait correlations beget performance trade-offs, (2 the influence that behavioral trait variants have on interspecific interactions and (3 mechanisms that aid in maintaining behavioral variation within- and among-populations. Research on behavioral syndromes continues to grow at an impressive rate, and we feel the success of behavioral syndromes studies in spiders bodes well for their continued prominence [Current Zoology 58 (4: 589–596, 2012].

  15. Spider phobics more easily see a spider in morphed schematic pictures

    Directory of Open Access Journals (Sweden)

    Partchev Ivailo

    2007-11-01

    Full Text Available Abstract Background Individuals with social phobia are more likely to misinterpret ambiguous social situations as more threatening, i.e. they show an interpretive bias. This study investigated whether such a bias also exists in specific phobia. Methods Individuals with spider phobia or social phobia, spider aficionados and non-phobic controls saw morphed stimuli that gradually transformed from a schematic picture of a flower into a schematic picture of a spider by shifting the outlines of the petals until they turned into spider legs. Participants' task was to decide whether each stimulus was more similar to a spider, a flower or to neither object while EEG was recorded. Results An interpretive bias was found in spider phobia on a behavioral level: with the first opening of the petals of the flower anchor, spider phobics rated the stimuli as more unpleasant and arousing than the control groups and showed an elevated latent trait to classify a stimulus as a spider and a response-time advantage for spider-like stimuli. No cortical correlates on the level of ERPs of this interpretive bias could be identified. However, consistent with previous studies, social and spider phobic persons exhibited generally enhanced visual P1 amplitudes indicative of hypervigilance in phobia. Conclusion Results suggest an interpretive bias and generalization of phobia-specific responses in specific phobia. Similar effects have been observed in other anxiety disorders, such as social phobia and posttraumatic stress disorder.

  16. Simulation and optimisation of a ground source heat pump with different ground heat exchanger configurations for a single-family residential house

    DEFF Research Database (Denmark)

    Pavlov, Georgi Krasimiroy; Olesen, Bjarne W.

    2012-01-01

    In the future there will be an increased demand for energy efficient cooling of residential buildings. Therefore it is essential to develop cooling concepts that are passive and/or using very little primary energy. A possible solution is a ground source heat pump combined with a low....... For the studied geographical location, passive cooling by bypassing the heat pump and using only the ground heat exchanger can provide acceptable room temperatures.......-temperature heating and high-temperature cooling system. The present work evaluates the performance in relation to thermal comfort and energy consumption of a GSHP with different GHE concepts. The different configurations are analyzed being part of the energy supply system of a low-energy residential house...

  17. The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression.

    Science.gov (United States)

    Babb, Paul L; Lahens, Nicholas F; Correa-Garhwal, Sandra M; Nicholson, David N; Kim, Eun Ji; Hogenesch, John B; Kuntner, Matjaž; Higgins, Linden; Hayashi, Cheryl Y; Agnarsson, Ingi; Voight, Benjamin F

    2017-06-01

    Spider silks are the toughest known biological materials, yet are lightweight and virtually invisible to the human immune system, and they thus have revolutionary potential for medicine and industry. Spider silks are largely composed of spidroins, a unique family of structural proteins. To investigate spidroin genes systematically, we constructed the first genome of an orb-weaving spider: the golden orb-weaver (Nephila clavipes), which builds large webs using an extensive repertoire of silks with diverse physical properties. We cataloged 28 Nephila spidroins, representing all known orb-weaver spidroin types, and identified 394 repeated coding motif variants and higher-order repetitive cassette structures unique to specific spidroins. Characterization of spidroin expression in distinct silk gland types indicates that glands can express multiple spidroin types. We find evidence of an alternatively spliced spidroin, a spidroin expressed only in venom glands, evolutionary mechanisms for spidroin diversification, and non-spidroin genes with expression patterns that suggest roles in silk production.

  18. Investigating the transverse optical structure of spider silk micro-fibers using quantitative optical microscopy

    Science.gov (United States)

    Little, Douglas J.; Kane, Deb M.

    2017-01-01

    The transverse optical structure of two orb-weaver (family Araneidae) spider dragline silks was investigated using a variant of the inverse-scattering technique. Immersing the silks in a closely refractive index-matched liquid, the minimum achievable image contrast was greater than expected for an optically homogeneous silk, given what is currently known about the optical absorption of these silks. This "excess contrast" indicated the presence of transverse optical structure within the spider silk. Applying electromagnetic scattering theory to a transparent double cylinder, the minimum achievable irradiance contrast for the Plebs eburnus and Argiope keyserlingi dragline silks was determined to be consistent with step index refractive index contrasts of 1-4×10-4 and 6-7×10-4, respectively, supposing outer-layer thicknesses consistent with previous TEM studies (50 nm and 100 nm, respectively). The possibility of graded index refractive index contrasts within the spider silks is also discussed. This is the strongest evidence, to date, that there is a refractive index contrast associated with the layered morphology of spider silks and/or variation of proportion of nanocrystalline components within the spider silk structure. The method is more generally applicable to optical micro-fibers, including those with refractive index variations on a sub-wavelength scale.

  19. Investigating the transverse optical structure of spider silk micro-fibers using quantitative optical microscopy

    Directory of Open Access Journals (Sweden)

    Little Douglas J.

    2016-10-01

    Full Text Available The transverse optical structure of two orb-weaver (family Araneidae spider dragline silks was investigated using a variant of the inverse-scattering technique. Immersing the silks in a closely refractive index-matched liquid, the minimum achievable image contrast was greater than expected for an optically homogeneous silk, given what is currently known about the optical absorption of these silks. This “excess contrast” indicated the presence of transverse optical structure within the spider silk. Applying electromagnetic scattering theory to a transparent double cylinder, the minimum achievable irradiance contrast for the Plebs eburnus and Argiope keyserlingi dragline silks was determined to be consistent with step index refractive index contrasts of 1−4×10−4 and 6–7×10−4, respectively, supposing outer-layer thicknesses consistent with previous TEM studies (50 nm and 100 nm, respectively. The possibility of graded index refractive index contrasts within the spider silks is also discussed. This is the strongest evidence, to date, that there is a refractive index contrast associated with the layered morphology of spider silks and/or variation of proportion of nanocrystalline components within the spider silk structure. The method is more generally applicable to optical micro-fibers, including those with refractive index variations on a sub-wavelength scale.

  20. PRELIMINARY DATA ON SPIDERS FAUNA (ARANEI OF PROTECTED AREAS IN KOSTANAY REGION (KAZAKHSTAN

    Directory of Open Access Journals (Sweden)

    A. V. Ponomarev

    2014-01-01

    Full Text Available Aim. Fauna of Kazakhstan includes about one thousand species of spiders according to the latest data (Logunov, Gromov, Timokhanov, 2012; Mikhailov, 2013. However, most of these data refers to the western and eastern regions of the country. Spiders fauna of Central Kazakhstan is poorly studied. The aim of this study is to summarize available data about spiders in protected areas of Kostanay Region of Kazakhstan. Location. Kostanay Region, Kazakhstan Methods. Spiders were collected in 2013 on territory of Naurzum State Reserve and Altyn Dala State Reserve using hand collection and soil traps. Results and main conclusions. Preliminary annotated list of 84 species, 49 genera and 15 families from protected areas of Kostanai Region of Kazakhstan based on original and literature data is given. Thirty five species of spiders are registered in Naurzum Reserve and fifty three species are found from Altyn Dala Reserve. Found a number of rare and little-know species (Hypsosinga kazachstanica, Shaitan elchini, Evippa kazachstanica 

  1. High throughput techniques to reveal the molecular physiology and evolution of digestion in spiders.

    Science.gov (United States)

    Fuzita, Felipe J; Pinkse, Martijn W H; Patane, José S L; Verhaert, Peter D E M; Lopes, Adriana R

    2016-09-07

    Spiders are known for their predatory efficiency and for their high capacity of digesting relatively large prey. They do this by combining both extracorporeal and intracellular digestion. Whereas many high throughput ("-omics") techniques focus on biomolecules in spider venom, so far this approach has not yet been applied to investigate the protein composition of spider midgut diverticula (MD) and digestive fluid (DF). We here report on our investigations of both MD and DF of the spider Nephilingis (Nephilengys) cruentata through the use of next generation sequencing and shotgun proteomics. This shows that the DF is composed of a variety of hydrolases including peptidases, carbohydrases, lipases and nuclease, as well as of toxins and regulatory proteins. We detect 25 astacins in the DF. Phylogenetic analysis of the corresponding transcript(s) in Arachnida suggests that astacins have acquired an unprecedented role for extracorporeal digestion in Araneae, with different orthologs used by each family. The results of a comparative study of spiders in distinct physiological conditions allow us to propose some digestion mechanisms in this interesting animal taxon. All the high throughput data allowed the demonstration that DF is a secretion originating from the MD. We identified enzymes involved in the extracellular and intracellular phases of digestion. Besides that, data analyses show a large gene duplication event in Araneae digestive process evolution, mainly of astacin genes. We were also able to identify proteins expressed and translated in the digestive system, which until now had been exclusively associated to venom glands.

  2. Influence of Crop Management and Environmental Factors on Wolf Spider Assemblages (Araneae: Lycosidae) in an Australian Cotton Cropping System.

    Science.gov (United States)

    Rendon, Dalila; Whitehouse, Mary E A; Hulugalle, Nilantha R; Taylor, Phillip W

    2015-02-01

    Wolf spiders (Lycosidae) are the most abundant ground-hunting spiders in the Australian cotton (Gossypium hirsutum L.) agroecosystems. These spiders have potential in controlling pest bollworms, Helicoverpa spp. (Lepidoptera: Noctuidae) in minimum-tilled fields. A study was carried out during a wet growing season (2011-2012) in Narrabri, New South Wales, Australia, to determine how different crop rotations and tillage affect wolf spider assemblages in cotton fields. Spider abundance and species richness did not differ significantly between simple plots (no winter crop) and complex plots (cotton-wheat Triticum aestivum L.-vetch Vicia benghalensis L. rotation). However, the wolf spider biodiversity, as expressed by the Shannon-Weaver and Simpson's indices, was significantly higher in complex plots. Higher biodiversity reflected a more even distribution of the most dominant species (Venatrix konei Berland, Hogna crispipes Koch, and Tasmanicosa leuckartii Thorell) and the presence of more rare species in complex plots. T. leuckartii was more abundant in complex plots and appears to be sensitive to farming disturbances, whereas V. konei and H. crispipes were similarly abundant in the two plot types, suggesting higher resilience or recolonizing abilities. The demographic structure of these three species varied through the season, but not between plot types. Environmental variables had a significant effect on spider assemblage, but effects of environment and plot treatment were overshadowed by the seasonal progression of cotton stages. Maintaining a high density and even distribution of wolf spiders that prey on Helicoverpa spp. should be considered as a conservation biological control element when implementing agronomic and pest management strategies.

  3. Spiders spinning electrically charged nano-fibres.

    Science.gov (United States)

    Kronenberger, Katrin; Vollrath, Fritz

    2015-01-01

    Most spider threads are on the micrometre and sub-micrometre scale. Yet, there are some spiders that spin true nano-scale fibres such as the cribellate orb spider, Uloborus plumipes. Here, we analyse the highly specialized capture silk-spinning system of this spider and compare it with the silk extrusion systems of the more standard spider dragline threads. The cribellar silk extrusion system consists of tiny, morphologically basic glands each terminating through exceptionally long and narrow ducts in uniquely shaped silk outlets. Depending on spider size, hundreds to thousands of these outlet spigots cover the cribellum, a phylogenetically ancient spinning plate. We present details on the unique functional design of the cribellate gland-duct-spigot system and discuss design requirements for its specialist fibrils. The spinning of fibres on the nano-scale seems to have been facilitated by the evolution of a highly specialist way of direct spinning, which differs from the aqua-melt silk extrusion set-up more typical for other spiders.

  4. 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.

  5. Spider silk gut: Development and characterization of a novel strong spider silk fiber

    OpenAIRE

    Ping Jiang; Núria Marí-Buyé; Rodrigo Madurga; María Arroyo-Hernández; Concepción Solanas; Alfonso Gañán; Rafael Daza; Plaza, Gustavo R.; Guinea, Gustavo V.; Manuel Elices; José Luis Cenis; José Pérez-Rigueiro

    2014-01-01

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much la...

  6. Spider silk gut: Development and characterization of a novel strong spider silk fiber

    OpenAIRE

    Ping Jiang; Núria Marí-Buyé; Rodrigo Madurga; María Arroyo-Hernández; Concepción Solanas; Alfonso Gañán; Rafael Daza; Plaza, Gustavo R.; Guinea, Gustavo V.; Manuel Elices; José Luis Cenis; José Pérez-Rigueiro

    2014-01-01

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much la...

  7. 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

    Science.gov (United States)

    Matsuda, Tomoko; Morishita, Maiko; Hinomoto, Norihide; Gotoh, Tetsuo

    2014-01-01

    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. PMID:25289639

  8. Spider Silk Spun and Integrated into Composites

    Science.gov (United States)

    2009-02-20

    Vollrath, F. The role of kinetics of water and amide bonding in protein stability Soft Matter , 4 328-336 2008 Holland, C.A. Vollrath F.V. Biomimetic... Soft Matter 2, 448^151 2006 Emile, O. Floch, A.L. Vollrath, F. The self shape-memory effect in spider draglines. Nature 440, 621 2006 Vollrath F...Porter Spider silk as archetypal protein elastomer. Soft Matter 2;377- 385 2006 Vollrath F, Porter, D. Spider silk as a model biomaterial. Applied

  9. Spiders for rank 2 Lie algebras

    CERN Document Server

    Kuperberg, G

    1996-01-01

    A spider is an axiomatization of the representation theory of a group, quantum group, Lie algebra, or other group or group-like object. We define certain combinatorial spiders by generators and relations that are isomorphic to the representation theories of the three rank two simple Lie algebras, namely A2, B2, and G2. They generalize the widely-used Temperley-Lieb spider for A1. Among other things, they yield bases for invariant spaces which are probably related to Lusztig's canonical bases, and they are useful for computing quantities such as generalized 6j-symbols and quantum link invariants.

  10. Spinning a laser web: predicting spider distributions using LiDAR.

    Science.gov (United States)

    Vierling, K T; Bässler, C; Brandl, R; Vierling, L A; Weiss, I; Müller, J

    2011-03-01

    LiDAR remote sensing has been used to examine relationships between vertebrate diversity and environmental characteristics, but its application to invertebrates has been limited. Our objectives were to determine whether LiDAR-derived variables could be used to accurately describe single-species distributions and community characteristics of spiders in remote forested and mountainous terrain. We collected over 5300 spiders across multiple transects in the Bavarian National Park (Germany) using pitfall traps. We examined spider community characteristics (species richness, the Shannon index, the Simpson index, community composition, mean body size, and abundance) and single-species distribution and abundance with LiDAR variables and ground-based measurements. We used the R2 and partial R2 provided by variance partitioning to evaluate the predictive power of LiDAR-derived variables compared to ground measurements for each of the community characteristics. The total adjusted R2 for species richness, the Shannon index, community species composition, and body size had a range of 25-57%. LiDAR variables and ground measurements both contributed >80% to the total predictive power. For species composition, the explained variance was approximately 32%, which was significantly greater than expected by chance. The predictive power of LiDAR-derived variables was comparable or superior to that of the ground-based variables for examinations of single-species distributions, and it explained up to 55% of the variance. The predictability of species distributions was higher for species that had strong associations with shade in open-forest habitats, and this niche position has been well documented across the European continent for spider species. The similar statistical performance between LiDAR and ground-based measures at our field sites indicated that deriving spider community and species distribution information using LiDAR data can provide not only high predictive power at

  11. Evidence from Multiple Species that Spider Silk Glue Component ASG2 is a Spidroin.

    Science.gov (United States)

    Collin, Matthew A; Clarke, Thomas H; Ayoub, Nadia A; Hayashi, Cheryl Y

    2016-02-15

    Spiders in the superfamily Araneoidea produce viscous glue from aggregate silk glands. Aggregate glue coats prey-capture threads and hampers the escape of prey from webs, thereby increasing the foraging success of spiders. cDNAs for Aggregate Spider Glue 1 (ASG1) and 2 (ASG2) have been previously described from the golden orb-weaver, Nephila clavipes, and Western black widow, Latrodectus hesperus. To further investigate aggregate glues, we assembled ASG1 and ASG2 from genomic target capture libraries constructed from three species of cob-web weavers and three species of orb-web weavers, all araneoids. We show that ASG1 is unlikely to be a glue, but rather is part of a widespread arthropod gene family, the peritrophic matrix proteins. For ASG2, we demonstrate its remarkable architectural and sequence similarities to spider silk fibroins, indicating that ASG2 is a member of the spidroin gene family. Thus, spidroins have diversified into glues in addition to task-specific, high performance fibers.

  12. Evidence from Multiple Species that Spider Silk Glue Component ASG2 is a Spidroin

    Science.gov (United States)

    Collin, Matthew A.; Clarke, Thomas H.; Ayoub, Nadia A.; Hayashi, Cheryl Y.

    2016-01-01

    Spiders in the superfamily Araneoidea produce viscous glue from aggregate silk glands. Aggregate glue coats prey-capture threads and hampers the escape of prey from webs, thereby increasing the foraging success of spiders. cDNAs for Aggregate Spider Glue 1 (ASG1) and 2 (ASG2) have been previously described from the golden orb-weaver, Nephila clavipes, and Western black widow, Latrodectus hesperus. To further investigate aggregate glues, we assembled ASG1 and ASG2 from genomic target capture libraries constructed from three species of cob-web weavers and three species of orb-web weavers, all araneoids. We show that ASG1 is unlikely to be a glue, but rather is part of a widespread arthropod gene family, the peritrophic matrix proteins. For ASG2, we demonstrate its remarkable architectural and sequence similarities to spider silk fibroins, indicating that ASG2 is a member of the spidroin gene family. Thus, spidroins have diversified into glues in addition to task-specific, high performance fibers. PMID:26875681

  13. Peptidomic and transcriptomic profiling of four distinct spider venoms

    Science.gov (United States)

    Oldrati, Vera; Koua, Dominique; Allard, Pierre-Marie; Hulo, Nicolas; Arrell, Miriam; Nentwig, Wolfgang; Lisacek, Frédérique; Wolfender, Jean-Luc; Kuhn-Nentwig, Lucia; Stöcklin, Reto

    2017-01-01

    Venom based research is exploited to find novel candidates for the development of innovative pharmacological tools, drug candidates and new ingredients for cosmetic and agrochemical industries. Moreover, venomics, as a well-established approach in systems biology, helps to elucidate the genetic mechanisms of the production of such a great molecular biodiversity. Today the advances made in the proteomics, transcriptomics and bioinformatics fields, favor venomics, allowing the in depth study of complex matrices and the elucidation even of minor compounds present in minute biological samples. The present study illustrates a rapid and efficient method developed for the elucidation of venom composition based on NextGen mRNA sequencing of venom glands and LC-MS/MS venom proteome profiling. The analysis of the comprehensive data obtained was focused on cysteine rich peptide toxins from four spider species originating from phylogenetically distant families for comparison purposes. The studied species were Heteropoda davidbowie (Sparassidae), Poecilotheria formosa (Theraphosidae), Viridasius fasciatus (Viridasiidae) and Latrodectus mactans (Theridiidae). This led to a high resolution profiling of 284 characterized cysteine rich peptides, 111 of which belong to the Inhibitor Cysteine Knot (ICK) structural motif. The analysis of H. davidbowie venom revealed a high richness in term of venom diversity: 95 peptide sequences were identified; out of these, 32 peptides presented the ICK structural motif and could be classified in six distinct families. The profiling of P. formosa venom highlighted the presence of 126 peptide sequences, with 52 ICK toxins belonging to three structural distinct families. V. fasciatus venom was shown to contain 49 peptide sequences, out of which 22 presented the ICK structural motif and were attributed to five families. The venom of L. mactans, until now studied for its large neurotoxins (Latrotoxins), revealed the presence of 14 cysteine rich

  14. Spider behaviors include oral sexual encounters

    Science.gov (United States)

    Gregorič, Matjaž; Šuen, Klavdija; Cheng, Ren-Chung; Kralj-Fišer, Simona; Kuntner, Matjaž

    2016-01-01

    Several clades of spiders whose females evolved giant sizes are known for extreme sexual behaviors such as sexual cannibalism, opportunistic mating, mate-binding, genital mutilation, plugging, and emasculation. However, these behaviors have only been tested in a handful of size dimorphic spiders. Here, we bring another lineage into the picture by reporting on sexual behavior of Darwin’s bark spider, Caerostris darwini. This sexually size dimorphic Madagascan species is known for extreme web gigantism and for producing the world’s toughest biomaterial. Our field and laboratory study uncovers a rich sexual repertoire that predictably involves cannibalism, genital mutilation, male preference for teneral females, and emasculation. Surprisingly, C. darwini males engage in oral sexual encounters, rarely reported outside mammals. Irrespective of female’s age or mating status males salivate onto female genitalia pre-, during, and post-copulation. While its adaptive significance is elusive, oral sexual contact in spiders may signal male quality or reduce sperm competition. PMID:27126507

  15. Spider-Venom Peptides as Therapeutics

    Directory of Open Access Journals (Sweden)

    Glenn F. King

    2010-12-01

    Full Text Available Spiders are the most successful venomous animals and the most abundant terrestrial predators. Their remarkable success is due in large part to their ingenious exploitation of silk and the evolution of pharmacologically complex venoms that ensure rapid subjugation of prey. Most spider venoms are dominated by disulfide-rich peptides that typically have high affinity and specificity for particular subtypes of ion channels and receptors. Spider venoms are conservatively predicted to contain more than 10 million bioactive peptides, making them a valuable resource for drug discovery. Here we review the structure and pharmacology of spider-venom peptides that are being used as leads for the development of therapeutics against a wide range of pathophysiological conditions including cardiovascular disorders, chronic pain, inflammation, and erectile dysfunction.

  16. Modelling Crop Biocontrol by Wanderer Spiders

    Science.gov (United States)

    Venturino, Ezio; Ghersi, Andrea

    2008-09-01

    We study mathematically the effects some spiders populations have on insects living in and near agroecosystems, where woods and vineyards alternate in the landscape as in the Alta Langa, Piemonte, NW Italy.

  17. Spider bite-induced erythema multiforme.

    Science.gov (United States)

    Özyurt, Selçuk; Er, Onur; Afsar, Fatma Sule; Ermete, Murat

    2013-09-01

    Erythema multiforme (EM) is an immune-mediated mucocutaneous eruption characterized by symmetrically distributed, polymorphic targetoid lesions, mostly on the distal parts of the extremities. It occurs mostly in the setting of an infection in certain predisposed individuals. A 30-year-old pregnant woman was presented with a necrotic erythematous lesion on her right thigh following a spider bite. As she was pregnant for 16 weeks, no systemic medication was given. On the 8th day of the spider bite an erythematous vesicular and targetoid rash was seen on the distal parts of her extremities. Based on the clinical and histopathological findings, lesions were diagnosed as EM. She had not used any medication for 4 months and she gave no prior history of herpetic infection. So her EM lesions were thought to be an ID reaction most probably due to the spider bite. As far as we know, this is the first reported case of EM induced by a spider bite.

  18. First Passage Properties of Molecular Spiders

    CERN Document Server

    Semenov, Oleg; Stefanovic, Darko

    2013-01-01

    Molecular spiders are synthetic catalytic DNA-based nanoscale walkers. We study the mean first passage time for abstract models of spiders moving on a finite two-dimensional lattice with various boundary conditions, and compare it with the mean first passage time of spiders moving on a one-dimensional track. We evaluate by how much the slowdown on newly visited sites, owing to catalysis, can improve the mean first passage time of spiders and show that in one dimension, when both ends of the track are an absorbing boundary, the performance gain is lower than in two dimensions, when the absorbing boundary is a circle; this persists even when the absorbing boundary is a single site.

  19. Neurological effects of venomous bites and stings: snakes, spiders, and scorpions.

    Science.gov (United States)

    Del Brutto, Oscar H

    2013-01-01

    Snake and spider bites, as well as scorpion sting envenoming, are neglected diseases affecting millions of people all over the world. Neurological complications vary according to the offending animal, and are often directly related to toxic effects of the venom, affecting the central nervous system, the neuromuscular transmission, the cardiovascular system, or the coagulation cascade. Snake bite envenoming may result in stroke or muscle paralysis. Metalloproteinases and other substances (common in vipers and colubrids) have anticoagulant or procoagulant activity, and may induce ischemic or hemorrhagic strokes. The venom of elapids is rich in neurotoxins affecting the neuromuscular transmission at either presynaptic or postsynaptic levels. The clinical picture of scorpion sting envenoming is dominated by muscle weakness associated with arterial hypertension, cardiac arrythmias, myocarditis, or pulmonary edema. These manifestations occur as the result of release of catecholamines into the bloodstream or due to direct cardiac toxicity of the venom. Cerebrovascular complications have been reported after the sting of the Indian red scorpion. Intracranial hemorrhages occur in the setting of acute increases in arterial blood pressure related to sympathetic overstimulation, and cerebral infarctions are related to either cerebral hypoperfusion, consumption coagulopathy, vasculitis, or cardiogenic brain embolism. Three main syndromes result from spider bite envenoming: latrodectism, loxoscelism, and funnel-web spider envenoming. Latrodectism is related to neurotoxins present in the venom of widow spiders. Most cases present with headache, lethargy, irritability, myalgia, tremor, fasciculation, or ataxia. Loxoscelism is caused by envenoming by spiders of the family Sicariidae. It may present with a stroke due to a severe coagulopathy. The venom of funnel-web spiders also has neurotoxins that stimulate neurotransmitter release, resulting in sensory disturbances and muscle

  20. On the diversity of some soil and cave spiders (Aranea: Arachnida from Serbia

    Directory of Open Access Journals (Sweden)

    Ćurčić Božidar P.

    2004-01-01

    Full Text Available A total of 46 species from 14 families: Pholcidae (2, Dysderidae (3 Eresidae (1, Linyphiidae (11, Tetragnathidae (3, Araneidae (4, Lycosidae (5, Agelenidae (4, Amaurobiidae (2, Liocranidae (1, Gnaphosidae (2 Philodromidae (1, Thomisidae (2 and Salticidae (5 were established from 29 localities in Serbia. Five species: Dysderocrates silvestris Deeleman-Reinhold (Dysderidae, Centromerus obenbergeri (Kulczyński, 1897 (Linyphiidae, Trochosa hispanica Simon, 1870, Trochosa spinipalpis (O. P.-Cambridge (Lycosidae and Philodromus praedatus O. P.-Cambridge are new to the Serbian spider fauna; the most diverse is the family Linyphiidae which is represented by 11 species. At the time, the spiders of Serbia are represented by 633 species, belonging to 224 genera and 36 families.

  1. Recombinant DNA production of spider silk proteins

    Science.gov (United States)

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

    2013-01-01

    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. PMID:24119078

  2. Spider's web inspires fibres for industry

    Science.gov (United States)

    Dacey, James

    2010-03-01

    Spiders may not be everybody's idea of natural beauty, but nobody can deny the artistry in the webs that they spin, especially when decorated with water baubles in the morning dew. Inspired by this spectacle, a group of researchers in China has mimicked the structural properties of the spider's web to create a fibre for industry that can manipulate water with the same skill and efficiency, writes James Dacey.

  3. Edge effect on weevils and spiders

    OpenAIRE

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

    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...

  4. The Aerodynamic Signature of Running Spiders

    OpenAIRE

    Jérôme Casas; Thomas Steinmann; Olivier Dangles

    2008-01-01

    International audience; 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 i...

  5. 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.

  6. Spinning gland transcriptomics from two main clades of spiders (order: Araneae--insights on their molecular, anatomical and behavioral evolution.

    Directory of Open Access Journals (Sweden)

    Francisco Prosdocimi

    Full Text Available Characterized by distinctive evolutionary adaptations, spiders provide a comprehensive system for evolutionary and developmental studies of anatomical organs, including silk and venom production. Here we performed cDNA sequencing using massively parallel sequencers (454 GS-FLX Titanium to generate ∼80,000 reads from the spinning gland of Actinopus spp. (infraorder: Mygalomorphae and Gasteracantha cancriformis (infraorder: Araneomorphae, Orbiculariae clade. Actinopus spp. retains primitive characteristics on web usage and presents a single undifferentiated spinning gland while the orbiculariae spiders have seven differentiated spinning glands and complex patterns of web usage. MIRA, Celera Assembler and CAP3 software were used to cluster NGS reads for each spider. CAP3 unigenes passed through a pipeline for automatic annotation, classification by biological function, and comparative transcriptomics. Genes related to spider silks were manually curated and analyzed. Although a single spidroin gene family was found in Actinopus spp., a vast repertoire of specialized spider silk proteins was encountered in orbiculariae. Astacin-like metalloproteases (meprin subfamily were shown to be some of the most sampled unigenes and duplicated gene families in G. cancriformis since its evolutionary split from mygalomorphs. Our results confirm that the evolution of the molecular repertoire of silk proteins was accompanied by the (i anatomical differentiation of spinning glands and (ii behavioral complexification in the web usage. Finally, a phylogenetic tree was constructed to cluster most of the known spidroins in gene clades. This is the first large-scale, multi-organism transcriptome for spider spinning glands and a first step into a broad understanding of spider web systems biology and evolution.

  7. Spider assemblage (Arachnida: Araneae associated with canopies of Vochysia divergens (Vochysiaceae in the northern region of the Brazilian Pantanal

    Directory of Open Access Journals (Sweden)

    Leandro D. Battirola

    Full Text Available ABSTRACT This study describes the composition and temporal variation of the spider assemblage (Arachnida: Araneae associated with canopies of Vochysia divergens Pohl. (Vochysiaceae in the northern region of the Brazilian Pantanal. Three V. divergens plants were sampled in 2004, at each seasonal period of the northern Pantanal (high water, receding water, dry season and rising water, using thermonebulization of the canopies with insecticide, totaling 396 m2 of sampled canopies. Analysis of abundance and richness of spider families were based on Non-Metric Multidimensional Scaling (NMDS and Variance Analysis (ANOVA and MANOVA. A total of 7,193 spiders were collected (6,330 immatures; 88.0%; 863 adults, 12.0% distributed in 30 families. Araneidae (1,676 individuals, Anyphaenidae (1,631 individuals, Salticidae (1,542 individuals and Pisauridae (906 individuals, were predominant, representing 80.0% of the sample. Ten different guilds were registered: aerial hunters, orb-weavers, nocturnal aerial runners and diurnal space web weavers dominated, sharing most ecological niches. The spider assemblage is affected by changes in the habitat structure, especially by the seasonal hydrological regime and variations in the phenology of V. divergens . The assemblage is composed of different groups of spiders. The dominant taxa and behavioral guilds differ in the different seasonal periods. Spiders were more abundant during the dry and rising water seasons, most likely reflecting a greater supply of potential prey, associated with new foliage and flowering at the canopy. The displacement of soil dwelling spiders to the trunks and canopies before and during the seasonal floods can change the structure and composition of the canopy assemblages. Oonopidae, Gnaphosidae and Caponiidae, were more frequent during the rising and high water seasons, which indicates that these taxa use the canopies of V. divergens as a refuge during the seasonal flooding in the Pantanal.

  8. Spinning Gland Transcriptomics from Two Main Clades of Spiders (Order: Araneae) - Insights on Their Molecular, Anatomical and Behavioral Evolution

    Science.gov (United States)

    Prosdocimi, Francisco; Bittencourt, Daniela; da Silva, Felipe Rodrigues; Kirst, Matias; Motta, Paulo C.; Rech, Elibio L.

    2011-01-01

    Characterized by distinctive evolutionary adaptations, spiders provide a comprehensive system for evolutionary and developmental studies of anatomical organs, including silk and venom production. Here we performed cDNA sequencing using massively parallel sequencers (454 GS-FLX Titanium) to generate ∼80,000 reads from the spinning gland of Actinopus spp. (infraorder: Mygalomorphae) and Gasteracantha cancriformis (infraorder: Araneomorphae, Orbiculariae clade). Actinopus spp. retains primitive characteristics on web usage and presents a single undifferentiated spinning gland while the orbiculariae spiders have seven differentiated spinning glands and complex patterns of web usage. MIRA, Celera Assembler and CAP3 software were used to cluster NGS reads for each spider. CAP3 unigenes passed through a pipeline for automatic annotation, classification by biological function, and comparative transcriptomics. Genes related to spider silks were manually curated and analyzed. Although a single spidroin gene family was found in Actinopus spp., a vast repertoire of specialized spider silk proteins was encountered in orbiculariae. Astacin-like metalloproteases (meprin subfamily) were shown to be some of the most sampled unigenes and duplicated gene families in G. cancriformis since its evolutionary split from mygalomorphs. Our results confirm that the evolution of the molecular repertoire of silk proteins was accompanied by the (i) anatomical differentiation of spinning glands and (ii) behavioral complexification in the web usage. Finally, a phylogenetic tree was constructed to cluster most of the known spidroins in gene clades. This is the first large-scale, multi-organism transcriptome for spider spinning glands and a first step into a broad understanding of spider web systems biology and evolution. PMID:21738742

  9. Summary statistics for fossil spider species taxonomy

    Directory of Open Access Journals (Sweden)

    David Penney

    2012-05-01

    Full Text Available Spiders (Araneae are one of the most species-rich orders on Earth today, and also have one of the longest geological records of any terrestrial animal groups, as demonstrated by their extensive fossil record. There are currently around 1150 described fossil spider species, representing 2.6% of all described spiders (i.e. extinct and extant. Data for numbers of fossil and living spider taxa described annually (and various other metrics for the fossil taxa were compiled from current taxonomic catalogues. Data for extant taxa showed a steady linear increase of approximately 500 new species per year over the last decade, reflecting a rather constant research activity in this area by a large number of scientists, which can be expected to continue. The results for fossil species were very different, with peaks of new species descriptions followed by long troughs, indicating minimal new published research activity for most years. This pattern is indicative of short bursts of research by a limited number of authors. Given the frequent discovery of new fossil deposits containing spiders, a wealth of new material coming to light from previously worked deposits, and the application of new imaging techniques in palaeoarachnology that allow us to extract additional data from historical specimens, e.g. X-ray computed tomography, it is important not only to ensure a sustained research activity on fossil spiders (and other arachnids through training and enthusing the next generation of palaeoarachnologists, but preferably to promote increased research and expertise in this field.

  10. 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.

  11. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

    OpenAIRE

    Roberson, Elizabeth J.; Chips, Michael J.; Walter P. Carson; Thomas P. Rooney

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau re...

  12. The Effects of Alcohol on Spiders: What Happens to Web Construction after Spiders Consume Alcohol?

    Science.gov (United States)

    Cross, Victor E.

    2006-01-01

    In the high school experiment reported in this paper, spiders were provided with 40% ethanol (ETOH) in order to determine the effects of alcohol on the web-spinning ability of orb weaver spiders. It was hypothesized that alcohol would have a deleterious effect on the number of radii, number of cells, and area of cells in the webs of orb weaving…

  13. 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

  14. EPR spectroscopy of a family of Cr(III) 7M(II) (M = Cd, Zn, Mn, Ni) "wheels": studies of isostructural compounds with different spin ground states

    DEFF Research Database (Denmark)

    Piligkos, Stergios; Weihe, Høgni; Bill, Eckhard

    2009-01-01

    Spinning wheels: The presented highly resolved multifrequency continuous wave EPR spectra (e.g., see figure) of the heterooctametalic "wheels" Cr(7)M provide rare examples of high nuclearity polymetallic systems where detailed information on the spin-Hamiltonian parameters of the ground and excited...... examples of high nuclearity polymetallic systems where detailed information on the spin-Hamiltonian parameters of the ground and excited spin states is observed. We interpret the EPR spectra by use of restricted size effective subspaces obtained by the rigorous solution of spin-Hamiltonians of dimension up...... to 10(5) by use of the Davidson algorithm. We show that transferability of spin-Hamiltonian parameters across complexes of the Cr(7)M family is possible and that the spin-Hamiltonian parameters of Cr(7)M do not have sharply defined values, but are rather distributed around a mean value....

  15. Mass predicts web asymmetry in Nephila spiders

    Science.gov (United States)

    Kuntner, Matjaž; Gregorič, Matjaž; Li, Daiqin

    2010-12-01

    The architecture of vertical aerial orb webs may be affected by spider size and gravity or by the available web space, in addition to phylogenetic and/or developmental factors. Vertical orb web asymmetry measured by hub displacement has been shown to increase in bigger and heavier spiders; however, previous studies have mostly focused on adult and subadult spiders or on several size classes with measured size parameters but no mass. Both estimations are suboptimal because (1) adult orb web spiders may not invest heavily in optimal web construction, whereas juveniles do; (2) size class/developmental stage is difficult to estimate in the field and is thus subjective, and (3) mass scales differently to size and is therefore more important in predicting aerial foraging success due to gravity. We studied vertical web asymmetry in a giant orb web spider, Nephila pilipes, across a wide range of size classes/developmental stages and tested the hypothesis that vertical web asymmetry (measured as hub displacement) is affected by gravity. On a sample of 100 webs, we found that hubs were more displaced in heavier and larger juveniles and that spider mass explained vertical web asymmetry better than other measures of spider size (carapace and leg lengths, developmental stage). Quantifying web shape via the ladder index suggested that, unlike in other nephilid taxa, growing Nephila orbs do not become vertically elongated. We conclude that the ontogenetic pattern of progressive vertical web asymmetry in Nephila can be explained by optimal foraging due to gravity, to which the opposing selective force may be high web-building costs in the lower orb. Recent literature finds little support for alternative explanations of ontogenetic orb web allometry such as the size limitation hypothesis and the biogenetic law.

  16. 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.

  17. 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.

  18. SPIDER OR NO SPIDER? NEURAL CORRELATES OF SUSTAINED AND PHASIC FEAR IN SPIDER PHOBIA.

    Science.gov (United States)

    Münsterkötter, Anna Luisa; Notzon, Swantje; Redlich, Ronny; Grotegerd, Dominik; Dohm, Katharina; Arolt, Volker; Kugel, Harald; Zwanzger, Peter; Dannlowski, Udo

    2015-09-01

    Processes of phasic fear responses to threatening stimuli are thought to be distinct from sustained, anticipatory anxiety toward an unpredicted, potential threat. There is evidence for dissociable neural correlates of phasic fear and sustained anxiety. Whereas increased amygdala activity has been associated with phasic fear, sustained anxiety has been linked with activation of the bed nucleus of stria terminalis (BNST), anterior cingulate cortex (ACC), and the insula. So far, only a few studies have focused on the dissociation of neural processes related to both phasic and sustained fear in specific phobia. We suggested that first, conditions of phasic and sustained fear would involve different neural networks and, second, that overall neural activity would be enhanced in a sample of phobic compared to nonphobic participants. Pictures of spiders and neutral stimuli under conditions of either predicted (phasic) or unpredicted (sustained) fear were presented to 28 subjects with spider phobia and 28 nonphobic control subjects during functional magnetic resonance imaging (fMRI) scanning. Phobic patients revealed significantly higher amygdala activation than controls under conditions of phasic fear. Sustained fear processing was significantly related to activation in the insula and ACC, and phobic patients showed a stronger activation than controls of the BNST and the right ACC under conditions of sustained fear. Functional connectivity analysis revealed enhanced connectivity of the BNST and the amygdala in phobic subjects. Our findings support the idea of distinct neural correlates of phasic and sustained fear processes. Increased neural activity and functional connectivity in these networks might be crucial for the development and maintenance of anxiety disorders. © 2015 Wiley Periodicals, Inc.

  19. Decision-making experiences of family members of older adults with moderate dementia towards community and residential care home services: a grounded theory study protocol.

    Science.gov (United States)

    Le Low, Lisa Pau; Lam, Lai Wah; Fan, Kim Pong

    2017-06-05

    Caring and supporting older people with dementia have become a major public health priority. Recent reports have also revealed a diminishing number of family carers to provide dementia care in the future. Carers who are engaged in the caring role are known to bear significant psychological, practical and economic challenges as the disease advances over time. Seemingly, evidence indicates that the burden of care can be relieved by formal services. This study aims to explore decision-making experiences of family members of older adults with moderate dementia towards the use of community support (CS) and residential care home (RCH) services. A large multi-site constructivist grounded theory in a range of non-government organizations and a private aged home will frame this Hong Kong study. Purposive sampling will begin the recruitment of family members, followed by theoretical sampling. It is estimated that more than 100 family members using CS and RCH services will participate in an interview. The process of successive constant comparative analysis will be undertaken. The final product, a theory, will generate an integrated and comprehensive conceptual understanding which will explain the processes associated with decision-making of family members for dementia sufferers. Deeper understanding of issues including, but not exclusive to, service needs, expectations and hopes among family carers for improving service support to serve dementia sufferers in CS and RCH services will also be revealed. Importantly, this study seeks to illustrate the practical and strategic aspects of the theory and how it may be useful to transfer its applicability to various service settings to better support those who deliver formal and informal care to the dementia population.

  20. A spider population in flux: selection and abandonment of artificial web-sites and the importance of intraspecific interactions in Lephthyphantes tenuis (Araneae: Linyphiidae) in wheat.

    Science.gov (United States)

    Samu, Ferenc; Sunderland, Keith D; Topping, Chris J; Fenlon, John S

    1996-04-01

    Lepthyphantes tenuis, a small sheet-webbuilding linyphiid spider is one of the most abundant spider species of cereal fields in Europe. In the present study we examined the process of web-site selection and web-site tenacity by adult females of this species in a winter wheat field. Spiders were selective in their choice of web-site. Different immigration rates into various manipulated web-sites, in field and laboratory, suggested that structural support and suitable micro-climate (high humidity) are the most important factors in the selection. Small holes dug in the ground were the most favoured web-sites. Web-site occupation was influenced by the presence of other conspecific spiders. Territorial contests occurred between spiders attempting to occupy the same web, these almost invariably led to the take-over of the web when the intruder was heavier. Interference, but also a certain level of tolerance, between spiders within the same web-site but in different webs was suggested by direct and indirect evidence. Many holes supported two or even three spiders in vertically stratified webs. Leaving probability of marked spiders was significantly higher in multiply occupied holes than in holes with a single web. Comparison with the results of a no-interference stochastic model showed that multiple occupancy in nature is less frequent than predicted by the model. There was further evidence for weak extra-web-interference between spiders in that multiple occupancy was even less frequent and overall occupancy was lower in web-sites which were packed close to each other. However, a level of tolerance for crowding is shown by the fact that closely packed hole colonies supported a spider density 13 times higher than in natural web-sites in the field. A marking experiment was carried out to gain information on web-site tenacity (i.e. the length of time a spider spends in a web-site) and abandonment. The average duration of tenacity was less than 2 days. A random loss function

  1. Foraging modality and plasticity in foraging traits determine the strength of competitive interactions among carnivorous plants, spiders and toads.

    Science.gov (United States)

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

    2016-07-01

    Foraging modalities (e.g. passive, sit-and-wait, active) and traits are plastic in some species, but the extent to which this plasticity affects interspecific competition remains unclear. Using a long-term laboratory mesocosm experiment, we quantified competition strength and the plasticity of foraging traits in a guild of generalist predators of arthropods with a range of foraging modalities. Each mesocosm contained eight passively foraging pink sundews, and we employed an experimental design where treatments were the presence or absence of a sit-and-wait foraging spider and actively foraging toad crossed with five levels of prey abundance. We hypothesized that actively foraging toads would outcompete the other species at low prey abundance, but that spiders and sundews would exhibit plasticity in foraging traits to compensate for strong competition when prey were limited. Results generally supported our hypotheses. Toads had a greater effect on sundews at low prey abundances, and toad presence caused spiders to locate webs higher above the ground. Additionally, the closer large spider webs were to the ground, the greater the trichome densities produced by sundews. Also, spider webs were larger with than without toads and as sundew numbers increased, and these effects were more prominent as resources became limited. Finally, spiders negatively affected toad growth only at low prey abundance. These findings highlight the long-term importance of foraging modality and plasticity of foraging traits in determining the strength of competition within and across taxonomic kingdoms. Future research should assess whether plasticity in foraging traits helps to maintain coexistence within this guild and whether foraging modality can be used as a trait to reliably predict the strength of competitive interactions. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  2. Individual and species-specific traits explain niche size and functional role in spiders as generalist predators.

    Science.gov (United States)

    Sanders, Dirk; Vogel, Esther; Knop, Eva

    2015-01-01

    The function of a predator within a community is greatly based on its trophic niche, that is the number and the strength of feeding links. In generalist predators, which feed on a wide range of prey, the size and position of the trophic niche is likely determined by traits such as hunting mode, the stratum they occur in, their body size and age. We used stable isotope analyses ((13)C and (15)N) to measure the trophic niche size of nine spider species within a forest hedge community and tested for species traits and individual traits that influence stable isotope enrichment, niche size and resource use. The spiders Enoplognatha, Philodromus, Floronia, and Heliophanus had large isotopic niches, which correspond to a more generalistic feeding behaviour. In contrast, Araneus, Metellina and Agelena, as top predators in the system, had rather narrow niches. We found a negative correlation between trophic position and niche size. Differences in trophic position in spiders were explained by body size, hunting modes and stratum, while niche size was influenced by hunting mode. In Philodromus, the size of the trophic niche increased significantly with age. Fitting spiders to functional groups according to their mean body size, hunting mode and their habitat domain resulted in largely separated niches, which indicates that these traits are meaningful for separating functional entities in spiders. Functional groups based on habitat domain (stratum) caught the essential functional differences between the species with species higher up in the vegetation feeding on flying insects and herb and ground species also preying on forest floor decomposers. Interestingly, we found a gradient from large species using a higher habitat domain and having a smaller niche to smaller species foraging closer to the ground and having a larger niche. This shows that even within generalist predators, such as spiders, there is a gradient of specialism that can be predicted by functional traits.

  3. The symphytognathoid spiders of the Gaoligongshan, Yunnan, China (Araneae, Araneoidea): Systematics and diversity of micro-orbweavers

    NARCIS (Netherlands)

    Miller, J.A.; Griswold, C.E.; Yin, C.M.

    2009-01-01

    A ten-year inventory of the Gaoligongshan in western Yunnan Province, China, yielded more than 1000 adult spider specimens belonging to the symphytognathoid families Theridiosomatidae, Mysmenidae, Anapidae, and Symphytognathidae. These specimens belong to 36 species, all herein described as new. In

  4. The symphytognathoid spiders of the Gaoligongshan, Yunnan, China (Araneae, Araneoidea): Systematics and diversity of micro-orbweavers

    NARCIS (Netherlands)

    Miller, J.A.; Griswold, C.E.; Yin, C.M.

    2009-01-01

    A ten-year inventory of the Gaoligongshan in western Yunnan Province, China, yielded more than 1000 adult spider specimens belonging to the symphytognathoid families Theridiosomatidae, Mysmenidae, Anapidae, and Symphytognathidae. These specimens belong to 36 species, all herein described as new. In

  5. Molecular Identification of Adult and Juvenile Linyphiid and Theridiid Spiders in Alpine Glacier Foreland Communities

    Science.gov (United States)

    Raso, Lorna; Sint, Daniela; Rief, Alexander; Kaufmann, Rüdiger; Traugott, Michael

    2014-01-01

    In glacier forelands spiders constitute a large proportion of the invertebrate community. Therefore, it is important to be able to determine the species that can be found in these areas. Linyphiid and theridiid spider identification is currently not possible in juvenile specimens using traditional morphological based methods, however, a large proportion of the population in these areas are usually juveniles. Molecular methods permit identification of species at different life stages, making juvenile identification possible. In this study we tested a molecular tool to identify the 10 most common species of Linyphiidae and Theridiidae found in three glacier foreland communities of the Austrian Alps. Two multiplex PCR systems were developed and over 90% of the 753 field-collected spiders were identified successfully. The species targeted were found to be common in all three valleys during the summer of 2010. A comparison between the molecular and morphological data showed that although there was a slight difference in the results, the overall outcome was the same independently of the identification method used. We believe the quick and reliable identification of the spiders via the multiplex PCR assays developed here will aid the study of these families in Alpine habitats. PMID:25050841

  6. Functional anatomy of the pretarsus in whip spiders (Arachnida, Amblypygi).

    Science.gov (United States)

    Wolff, Jonas O; Seiter, Michael; Gorb, Stanislav N

    2015-11-01

    Whip spiders (Amblypygi) are a small, cryptic order of arachnids mainly distributed in the tropics. Some basal lineages (families Charinidae and Charontidae) have adhesive pads on the tips of their six walking legs. The present study describes the macro- and ultrastructure of these pads and investigates their contact mechanics and adhesive strength on smooth and rough substrates. Furthermore, the structure of the pretarsus and its kinematics are compared in Charon cf. grayi (with an adhesive pad) and Phrynus longipes (without an adhesive pad). The adhesive pads exhibit an elaborate structure with a unique combination of structural features of smooth and hairy foot pads including a long transversal contact zone performing lateral detachment, a thick internally-branched cuticle with longitudinal ribs and hexagonal surface microstructures with spatulate keels. The contact area of the pads on smooth glass is discontinuous due to the spatulate microstructures with a discontinuous detachment, which could be observed in vivo by high speed videography at a rate of up to 10,000 fps. Adhesive strength was measured with vertical whole animal pull-off tests, obtaining mean values between 55 and 200 kPa. The occurrence of viscous lipid secretions between microstructures was occasionally observed, which, however, seems not to be a necessity for good foothold. The results are discussed in relation to the whip spider's ecology and evolution. Structure-function relationships of the adhesive pads are compared to those of insects and vertebrates.

  7. Complications and outcomes of brown recluse spider bites in children.

    Science.gov (United States)

    Hubbard, Jonathan J; James, Laura P

    2011-03-01

    Brown recluse spider bites may cause severe local and systemic morbidity, but data regarding morbidity in children are limited. This study reviewed inpatient medical records (n = 26; 10 years) with a discharge diagnosis of "spider bite" from a tertiary pediatric hospital. The majority (85%) of children had an inflammatory response accompanying necrosis, usually with signs of secondary cellulitis (77%). Hemolytic anemia (50%), rhabdomyolysis (27%), and acute renal failure (12%) were the most prevalent systemic effects. Hemolytic anemia was bimodal in distribution relative to the time-of-onset of the bite (early, 2.2 ± 0.4; late, 6.9 ± 1.5 days postbite, respectively; P = .004). Although no fatalities occurred in the population, 65% of children had major morbidity, including wound complications requiring surgical care and acute orbital compartment syndrome. The findings emphasize the importance of anticipatory patient/family education for outpatients and careful monitoring for systemic morbidity in inpatients. Timely and appropriate supportive care should yield favorable outcomes in most cases.

  8. An insecticidal toxin from Nephila clavata spider venom.

    Science.gov (United States)

    Jin, Lin; Fang, Mingqian; Chen, Mengrou; Zhou, Chunling; Ombati, Rose; Hakim, Md Abdul; Mo, Guoxiang; Lai, Ren; Yan, Xiuwen; Wang, Yumin; Yang, Shilong

    2017-07-01

    Spiders are the most successful insect predators given that they use their venom containing insecticidal peptides as biochemical weapons for preying. Due to the high specificity and potency of peptidic toxins, discoveries of insecticidal toxins from spider venom have provided an opportunity to obtain natural compounds for agricultural applications without affecting human health. In this study, a novel insecticidal toxin (μ-NPTX-Nc1a) was identified and characterized from the venom of Nephila clavata. Its primary sequence is GCNPDCTGIQCGWPRCPGGQNPVMDKCVSCCPFCPPKSAQG which was determined by automated Edman degradation, cDNA cloning, and MS/MS analysis. BLAST search indicated that Nc1a shows no similarity with known peptides or proteins, indicating that Nc1a belongs to a novel family of insecticidal peptide. Nc1a displayed inhibitory effects on NaV and KV channels in cockroach dorsal unpaired median neurons. The median lethal dose (LD50) of Nc1a on cockroach was 573 ng/g. Herein, a study that identifies a novel insecticidal toxin, which can be a potential candidate and/or template for the development of bioinsecticides, is presented.

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Jaroslaw M Michalowski

    Full Text Available 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.

  11. Exploring the shock response of spider webs.

    Science.gov (United States)

    Tietsch, V; Alencastre, J; Witte, H; Torres, F G

    2016-03-01

    Spider orb-webs are designed to allow for quick energy absorption as well as the constraint of drastic oscillations occurring upon prey impact. Studies on spider silk illustrate its impressive mechanical properties and its capacity to be used as technical fibers in composite materials. Models have previously been used to study the mechanical properties of different silk fibers, but not the behavior of the spider web as a whole. Full spider webs have been impacted by a projectile and the transverse displacement was measured by means of a laser interferometer. The damping and stiffness of the entire webs were quantified considering the orb-web as a single-degree-of-freedom (SDOF) system. The amplitude, the period duration, and the energy dissipation of the oscillations have also been reported from the experiments. The analysis of the energy dissipation confirmed that the webs of orb-web spiders are optimized for the capture of a single or few large prey, rather than several small prey. The experiments also confirmed that the overall stiffness of the web displayed a non-linear behavior. Such non-linearity was also observed in the damping characteristics of the webs studied.

  12. Optics of spider "sticky" orb webs

    Science.gov (United States)

    Kane, Deb M.; Staib, Gregory R.; Naidoo, Nishen; Little, Douglas J.; Herberstein, Marie E.

    2011-04-01

    Spider orb webs are known to produce colour displays in nature, both in reflection and transmission of sunlight, under certain illumination conditions. The cause of these colours has been the subject of speculation since the time of Newton. It has also been the topic of observational interpretation and some experiment which has proposed diffraction by the fine silks, scattering from rough/structured surfaces and thin film effects as the primary causes. We report systematic studies carried out using the silks of Australian orb web weaving spiders. Studies of both white light and laser light scattering/propagation by natural spider silks have definitively determined the primary cause of the colour displays is rainbows that can be understood by the application of geometric optics combined with new knowledge of the optical properties of the spider web strands, silks, and proteins as optical materials. Additionally, a range of microscopies (optical, AFM, optical surface profiling) show the silks to be optically flat. Overall, spider silks emerge as fascinating optical materials with high dispersion, high birefringence and the potential for future research to show they have high nonlinear optical coefficients. Their importance as a bioinspiration in optics is only just beginning to be realised. Their special optical properties have been achieved by ~136 million years of evolution driven by the need for the web to evade detection by insect prey.

  13. 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...

  14. DNA barcode data accurately assign higher spider taxa

    Directory of Open Access Journals (Sweden)

    Jonathan A. Coddington

    2016-07-01

    Full Text Available The use of unique DNA sequences as a method for taxonomic identification is no longer fundamentally controversial, even though debate continues on the best markers, methods, and technology to use. Although both existing databanks such as GenBank and BOLD, as well as reference taxonomies, are imperfect, in best case scenarios “barcodes” (whether single or multiple, organelle or nuclear, loci clearly are an increasingly fast and inexpensive method of identification, especially as compared to manual identification of unknowns by increasingly rare expert taxonomists. Because most species on Earth are undescribed, a complete reference database at the species level is impractical in the near term. The question therefore arises whether unidentified species can, using DNA barcodes, be accurately assigned to more inclusive groups such as genera and families—taxonomic ranks of putatively monophyletic groups for which the global inventory is more complete and stable. We used a carefully chosen test library of CO1 sequences from 49 families, 313 genera, and 816 species of spiders to assess the accuracy of genus and family-level assignment. We used BLAST queries of each sequence against the entire library and got the top ten hits. The percent sequence identity was reported from these hits (PIdent, range 75–100%. Accurate assignment of higher taxa (PIdent above which errors totaled less than 5% occurred for genera at PIdent values >95 and families at PIdent values ≥ 91, suggesting these as heuristic thresholds for accurate generic and familial identifications in spiders. Accuracy of identification increases with numbers of species/genus and genera/family in the library; above five genera per family and fifteen species per genus all higher taxon assignments were correct. We propose that using percent sequence identity between conventional barcode sequences may be a feasible and reasonably accurate method to identify animals to family/genus. However

  15. Spider-venom peptides that target voltage-gated sodium channels: pharmacological tools and potential therapeutic leads.

    Science.gov (United States)

    Klint, Julie K; Senff, Sebastian; Rupasinghe, Darshani B; Er, Sing Yan; Herzig, Volker; Nicholson, Graham M; King, Glenn F

    2012-09-15

    Voltage-gated sodium (Na(V)) channels play a central role in the propagation of action potentials in excitable cells in both humans and insects. Many venomous animals have therefore evolved toxins that modulate the activity of Na(V) channels in order to subdue their prey and deter predators. Spider venoms in particular are rich in Na(V) channel modulators, with one-third of all known ion channel toxins from spider venoms acting on Na(V) channels. Here we review the landscape of spider-venom peptides that have so far been described to target vertebrate or invertebrate Na(V) channels. These peptides fall into 12 distinct families based on their primary structure and cysteine scaffold. Some of these peptides have become useful pharmacological tools, while others have potential as therapeutic leads because they target specific Na(V) channel subtypes that are considered to be important analgesic targets. Spider venoms are conservatively predicted to contain more than 10 million bioactive peptides and so far only 0.01% of this diversity been characterised. Thus, it is likely that future research will reveal additional structural classes of spider-venom peptides that target Na(V) channels.

  16. Characterization and expression of a cDNA encoding a tubuliform silk protein of the golden web spider Nephila antipodiana.

    Science.gov (United States)

    Huang, W; Lin, Z; Sin, Y M; Li, D; Gong, Z; Yang, D

    2006-07-01

    Spider silks are renowned for their excellent mechanical properties. Although several spider fibroin genes, mainly from dragline and capture silks, have been identified, there are still many members in the spider fibroin gene family remain uncharacterized. In this study, a novel silk cDNA clone from the golden web spider Nephila antipodiana was isolated. It is serine rich and contains two almost identical fragments with one varied gap region and one conserved spider fibroin-like C-terminal domain. Both in situ hybridization and immunoblot analyses have shown that it is specifically expressed in the tubuliform gland. Thus, it likely encodes the silk fibroin from the tubuliform gland, which supplies the main component of the inner egg case. Unlike other silk proteins, the protein encoded by the novel cDNA in water solution exhibits the characteristic of an alpha-helical protein, which implies the distinct property of the egg case silk, though the fiber of tubuliform silk is mainly composed of beta-sheet structure. Its sequence information facilitates elucidation of the evolutionary history of the araneoid fibroin genes.

  17. Mercury bioaccumulation, speciation, and influence on web structure in orb-weaving spiders from a forested watershed.

    Science.gov (United States)

    Wyman, Katherine E; Rodenhouse, Nicholas L; Bank, Michael S

    2011-08-01

    Atmospheric deposition is an important source of Hg in remote terrestrial ecosystems of northeastern North America. As high-level invertebrate consumers, orb-weaving spiders (family Araneidae) are excellent subjects for studying the impact of sublethal levels of Hg on forest animals because their webs provide snapshots of behavior and neurological function. Spiders of the diadematus group of the genus Araneus were collected from the Jeffers Brook watershed in the White Mountain National Forest, New Hampshire (USA), and analyzed for Hg content. Webs were photographed and measured to test for correlations between Hg body burden and web structure. Collected spiders contained concentrations of total Hg averaging 44.7 ± 10.0 ng/g Hg (wet mass; mean ± standard deviation), with 37 ± 6% of the total Hg present in the methylmercury form. Mercury loads were likely accumulated through diet (potential prey items contained an average of 43% of the Hg load in collected spiders) and possibly web ingestion. The present study found no direct evidence that the web structure-and thus the prey-capture ability-of spiders in the study area was affected by their Hg body burden. Copyright © 2011 SETAC.

  18. Hydraulic leg extension is not necessarily the main drive in large spiders.

    Science.gov (United States)

    Weihmann, Tom; Günther, Michael; Blickhan, Reinhard

    2012-02-15

    Unlike most other arthropods, spiders have no extensor muscles in major leg joints. Therefore, hydraulic pressure generated in the prosoma provides leg extension. For decades, this mechanism was held responsible for the generation of the majority of the ground reaction forces, particularly in the hind legs. During propulsion, the front leg pairs must shorten whereas the hind legs have to be extended. Assuming that hind legs are essentially driven by hydraulics, their force vectors must pass the leg joints ventrally. However, at least in accelerated escape manoeuvres, we show here for the large cursorial spider species Ancylometes concolor that these force vectors, when projected into the leg plane, pass all leg joints dorsally. This indicates a reduced impact of the hydraulic mechanism on the generation of ground reaction forces. Although hydraulic leg extension still modulates their direction, the observed steep force vectors at the hind legs indicate a strong activity of flexors in the proximal joint complex that push the legs against the substrate. Consequently, the muscular mechanisms are dominant at least in the hind legs of large spiders.

  19. Spider web-inspired acoustic metamaterials

    Science.gov (United States)

    Miniaci, Marco; Krushynska, Anastasiia; Movchan, Alexander B.; Bosia, Federico; Pugno, Nicola M.

    2016-08-01

    Spider silk is a remarkable example of bio-material with superior mechanical characteristics. Its multilevel structural organization of dragline and viscid silk leads to unusual and tunable properties, extensively studied from a quasi-static point of view. In this study, inspired by the Nephila spider orb web architecture, we propose a design for mechanical metamaterials based on its periodic repetition. We demonstrate that spider-web metamaterial structure plays an important role in the dynamic response and wave attenuation mechanisms. The capability of the resulting structure to inhibit elastic wave propagation in sub-wavelength frequency ranges is assessed, and parametric studies are performed to derive optimal configurations and constituent mechanical properties. The results show promise for the design of innovative lightweight structures for tunable vibration damping and impact protection, or the protection of large scale infrastructure such as suspended bridges.

  20. Formaldehyde biofiltration as affected by spider plant.

    Science.gov (United States)

    Xu, Zhongjun; Qin, Na; Wang, Jinggang; Tong, Hua

    2010-09-01

    The kinetic process of formaldehyde biodegradation in a biofilter packed with a mixture of compost, vermiculite powder and ceramic particles was investigated in this study. The results showed that more than 60% of formaldehyde was removed by the first 5 cm high biofilter bed at 406 Lh(-1) flowrate within the range of 5-207 mgm(-3) inlet concentrations. A macrokinetic model was applied to describe the kinetic process of formaldehyde biodegradation and the experimentally determined elimination capacity for the biofilter agreed well with the model predicted values. The data on the effect of spider plant (Chlorophytum comosum L.) on formaldehyde removal indicated that formaldehyde biofiltration might be stimulated by spider plant since formaldehyde was assimilated by spider plant roots and microbial formaldehyde degradation was enhanced by the root exudates.

  1. Insights into brown spider and loxoscelism

    Directory of Open Access Journals (Sweden)

    MH Appel

    2005-12-01

    Full Text Available Loxosceles is a genus of cosmopolitan spiders comprising several species, and popularly knownas brown spiders or brown recluses. Brown spider bites can cause dermonecrotic lesions andsystemic reactions known as loxoscelism. Systemic effects are less common but may be severe oreven fatal in some patients. Systemic manifestations include intravascular hemolysis, disseminatedintravascular coagulation and acute renal failure. A rapid diagnosis and an understanding of thevenom’s molecular activity are crucial for satisfactory treatment. Mechanisms by which venoms exerttheir deleterious effects are under investigation, and searches are underway for diagnosticenvenomation assays. Molecular biology is being used to produce quantities of several of the mostimportant venom molecules and has contributed to the study and understanding of their mechanismsof action.

  2. 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.

  3. Optically probing torsional superelasticity in spider silks

    Science.gov (United States)

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

    2013-11-01

    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 102-3 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.

  4. 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.

  5. Cooperative effects enhance the transport properties of molecular spider teams

    CERN Document Server

    Rank, Matthias; Frey, Erwin

    2013-01-01

    Molecular spiders are synthetic molecular motors based on DNA nanotechnology. While natural molecular motors have evolved towards very high efficiency, it remains a major challenge to develop efficient designs for man-made molecular motors. Inspired by biological motor proteins like kinesin and myosin, molecular spiders comprise a body and several legs. The legs walk on a lattice that is coated with substrate which can be cleaved catalytically. We propose a novel molecular spider design in which n spiders form a team. Our theoretical considerations show that coupling several spiders together alters the dynamics of the resulting team significantly. Although spiders operate at a scale where diffusion is dominant, spider teams can be tuned to behave nearly ballistic, which results in fast and predictable motion. Based on the separation of time scales of substrate and product dwell times, we develop a theory which utilises equivalence classes to coarse-grain the micro-state space. In addition, we calculate diffus...

  6. Cob-Weaving Spiders Design Attachment Discs Differently for Locomotion and Prey Capture

    Science.gov (United States)

    Sahni, Vasav; Harris, Jared; Blackledge, Todd; Dhinojwala, Ali

    2013-03-01

    Spiders' cobwebs ensnare both walking and flying prey. While the scaffolding silk can entangle flying insects, gumfoot silk threads pull walking prey off the ground and into the web. Therefore, scaffolding silk needs to withstand the impact of the prey, whereas gumfoot silk needs to easily detach from the substrate when contacted by prey. Here, we show that spiders accomplish these divergent demands by creating attachment discs of two distinct architectures using the same pyriform silk. A ``staple-pin'' architecture firmly attaches the scaffolding silk to the substrate and a previously unknown ``dendritic'' architecture weakly attaches the gumfoot silk to the substrate. Gumfoot discs adhere weakly, triggering a spring-loaded trap, while the strong adhesion of scaffolding discs compels the scaffolding threads to break instead of detaching. We describe the differences in adhesion for these two architectures using tape-peeling models and design synthetic attachments that reveal important design principles for controlled adhesion. National Science Foundation

  7. Optics of Spider Sticky Orb Webs

    Science.gov (United States)

    2011-01-01

    J. Martin- Palma , Akhlesh Lakhtakia, Proc. of SPIE Vol. 7975, 79750G · © 2011 SPIE · CCC code: 0277-786X/11/$18 · doi: 10.1117/12.880665 Proc. of...2] Opell, B.D., ’’Economics of Spider Orb-Webs: The Benefits of Producing Adhesive Capture Thread and of Recycling Silk", Functional Ecology , 12(4...8] Craig, C. L., "Insect perception of spider orb webs in three light habitats", Functional Ecology 2, 277-282 (1988). [9] Craig, C. L., Bernard, G

  8. Spider Silk: Mother Nature's Bio-Superlens

    Science.gov (United States)

    Monks, James N.; Yan, Bing; Hawkins, Nicholas; Vollrath, Fritz; Wang, Zengbo

    2016-09-01

    This paper demonstrates a possible new microfiber bio near field lens that uses minor ampullate spider silk,spun from the Nephila edulis spider, to create a real time image of a surface using near field optical techniques. The microfiber bio lens is the world's first natural superlens created by exploring biological materials. The resolution of the surface image overcomes the diffraction limit, with the ability to resolve patterns at 100 nm under a standard white light source in reflection mode. This resolution offers further developments in superlens technology and paves the way for new bio optics.

  9. Spider Silk: The Mother Nature's Biological Superlens

    CERN Document Server

    Monks, James N; Wang, Zengbo

    2016-01-01

    This paper demonstrates a possible new microfiber bio near field lens that uses minor ampullate spider silk,spun from the Nephila edulis spider, to create a real time image of a surface using near field optical techniques. The microfiber bio lens is the world's first natural superlens created by exploring biological materials. The resolution of the surface image overcomes the diffraction limit, with the ability to resolve patterns at 100 nm under a standard white light source in reflection mode. This resolution offers further developments in superlens technology and paves the way for new bio optics.

  10. Black widow spider bite: a case study.

    Science.gov (United States)

    Gaisford, Kristine; Kautz, Donald D

    2011-01-01

    This article is a case study of a patient cared for in the hours before her death. After the patient's death, we learned the patient died of a black widow spider bite. This article sheds light on the potential seriousness of this venom and allows for more rapid detection and treatment of those who are unfortunate enough to be bitten. The authors have documented the sequence of events for the patient, outlined the care the patient received, examined the pathophysiology of the body to a spider bite, and then made a passionate appeal for other nurses who work in critical care to do the same with patients in similar situations.

  11. Assessing and managing spider and scorpion envenomation.

    Science.gov (United States)

    McGhee, Stephen; Weiner, Aaron; Finnegan, Alan; Visovsky, Constance; Clochesy, John M; Graves, Brian

    2015-11-01

    Envenomation by spiders or scorpions is a public health problem in many parts of the world and is not isolated to the tropics and subtropics. Spiders and scorpions can be unintentionally transported globally, and keeping them as pets is becoming more popular, so envenomation can occur anywhere. Emergency nurses should be prepared to assess and treat patients who present with a bite or sting. This article gives an overview of the signs, symptoms and treatment of envenomation by species of arachnids that are clinically significant to humans.

  12. 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

  13. Upside-down spiders build upside-down orb webs: web asymmetry, spider orientation and running speed in Cyclosa.

    Science.gov (United States)

    Nakata, Kensuke; Zschokke, Samuel

    2010-10-07

    Almost all spiders building vertical orb webs face downwards when sitting on the hubs of their webs, and their webs exhibit an up-down size asymmetry, with the lower part of the capture area being larger than the upper. However, spiders of the genus Cyclosa, which all build vertical orb webs, exhibit inter- and intraspecific variation in orientation. In particular, Cyclosa ginnaga and C. argenteoalba always face upwards, and C. octotuberculata always face downwards, whereas some C. confusa face upwards and others face downwards or even sideways. These spiders provide a unique opportunity to examine why most spiders face downwards and have asymmetrical webs. We found that upward-facing spiders had upside-down webs with larger upper parts, downward-facing spiders had normal webs with larger lower parts and sideways-facing spiders had more symmetrical webs. Downward-facing C. confusa spiders were larger than upward- and sideways-facing individuals. We also found that during prey attacks, downward-facing spiders ran significantly faster downwards than upwards, which was not the case in upward-facing spiders. These results suggest that the spider's orientation at the hub and web asymmetry enhance its foraging efficiency by minimizing the time to reach prey trapped in the web.

  14. Upside-down spiders build upside-down orb webs: web asymmetry, spider orientation and running speed in Cyclosa

    Science.gov (United States)

    Nakata, Kensuke; Zschokke, Samuel

    2010-01-01

    Almost all spiders building vertical orb webs face downwards when sitting on the hubs of their webs, and their webs exhibit an up–down size asymmetry, with the lower part of the capture area being larger than the upper. However, spiders of the genus Cyclosa, which all build vertical orb webs, exhibit inter- and intraspecific variation in orientation. In particular, Cyclosa ginnaga and C. argenteoalba always face upwards, and C. octotuberculata always face downwards, whereas some C. confusa face upwards and others face downwards or even sideways. These spiders provide a unique opportunity to examine why most spiders face downwards and have asymmetrical webs. We found that upward-facing spiders had upside-down webs with larger upper parts, downward-facing spiders had normal webs with larger lower parts and sideways-facing spiders had more symmetrical webs. Downward-facing C. confusa spiders were larger than upward- and sideways-facing individuals. We also found that during prey attacks, downward-facing spiders ran significantly faster downwards than upwards, which was not the case in upward-facing spiders. These results suggest that the spider's orientation at the hub and web asymmetry enhance its foraging efficiency by minimizing the time to reach prey trapped in the web. PMID:20462900

  15. Diverse formulas for spider dragline fibers demonstrated by molecular and mechanical characterization of spitting spider silk.

    Science.gov (United States)

    Correa-Garhwal, Sandra M; Garb, Jessica E

    2014-12-08

    Spider silks have outstanding mechanical properties. Most research has focused on dragline silk proteins (major ampullate spidroins, MaSps) from orb-weaving spiders. Using silk gland expression libraries from the haplogyne spider Scytodes thoracica, we discovered two novel spidroins (S. thoracica fibroin 1 and 2). The amino acid composition of S. thoracica silk glands and dragline fibers suggest that fibroin 1 is the major component of S. thoracica dragline silk. Fibroin 1 is dominated by glycine-alanine motifs, and lacks sequence motifs associated with orb-weaver MaSps. We hypothesize fibroin 2 is a piriform or aciniform silk protein, based on amino acid composition, spigot morphology, and phylogenetic analyses. S. thoracica's dragline silk is less tough than previously reported, but is still comparable to other dragline silks. Our analyses suggest that dragline silk proteins evolved multiple times. This demonstrates that spider dragline silk is more diverse than previously understood, providing alternative high performance silk designs.

  16. Venom of the Brazilian spider Sicarius ornatus (Araneae, Sicariidae contains active sphingomyelinase D: potential for toxicity after envenomation.

    Directory of Open Access Journals (Sweden)

    Priscila Hess Lopes

    Full Text Available BACKGROUND: The spider family Sicariidae includes two genera, Sicarius and Loxosceles. Bites by Sicarius are uncommon in humans and, in Brazil, a single report is known of a 17-year old man bitten by a Sicarius species that developed a necrotic lesion similar to that caused by Loxosceles. Envenomation by Loxosceles spiders can result in dermonecrosis and severe ulceration. Sicarius and Loxosceles spider venoms share a common characteristic, i.e., the presence of Sphingomyelinases D (SMase D. We have previously shown that Loxosceles SMase D is the enzyme responsible for the main pathological effects of the venom. Recently, it was demonstrated that Sicarius species from Africa, like Loxosceles spiders from the Americas, present high venom SMase D activity. However, despite the presence of SMase D like proteins in venoms of several New World Sicarius species, they had reduced or no detectable SMase D activity. In order to contribute to a better understanding about the toxicity of New World Sicarius venoms, the aim of this study was to characterize the toxic properties of male and female venoms from the Brazilian Sicarius ornatus spider and compare these with venoms from Loxosceles species of medical importance in Brazil. METHODOLOGY/PRINCIPAL FINDINGS: SDS-PAGE analysis showed variations in the composition of Loxosceles spp. and Sicarius ornatus venoms. Differences in the electrophoretic profiles of male and female venoms were also observed, indicating a possible intraspecific variation in the composition of the venom of Sicarius spider. The major component in all tested venoms had a Mr of 32-35 kDa, which was recognized by antiserum raised against Loxosceles SMases D. Moreover, male and female Sicarius ornatus spiders' venoms were able to hydrolyze sphingomyelin, thus showing an enzymatic activity similar to that determined for Loxosceles venoms. Sicarius ornatus venoms, as well as Loxosceles venoms, were able to render erythrocytes susceptible to

  17. Venom of the Brazilian spider Sicarius ornatus (Araneae, Sicariidae) contains active sphingomyelinase D: potential for toxicity after envenomation.

    Science.gov (United States)

    Lopes, Priscila Hess; Bertani, Rogério; Gonçalves-de-Andrade, Rute M; Nagahama, Roberto H; van den Berg, Carmen W; Tambourgi, Denise V

    2013-01-01

    The spider family Sicariidae includes two genera, Sicarius and Loxosceles. Bites by Sicarius are uncommon in humans and, in Brazil, a single report is known of a 17-year old man bitten by a Sicarius species that developed a necrotic lesion similar to that caused by Loxosceles. Envenomation by Loxosceles spiders can result in dermonecrosis and severe ulceration. Sicarius and Loxosceles spider venoms share a common characteristic, i.e., the presence of Sphingomyelinases D (SMase D). We have previously shown that Loxosceles SMase D is the enzyme responsible for the main pathological effects of the venom. Recently, it was demonstrated that Sicarius species from Africa, like Loxosceles spiders from the Americas, present high venom SMase D activity. However, despite the presence of SMase D like proteins in venoms of several New World Sicarius species, they had reduced or no detectable SMase D activity. In order to contribute to a better understanding about the toxicity of New World Sicarius venoms, the aim of this study was to characterize the toxic properties of male and female venoms from the Brazilian Sicarius ornatus spider and compare these with venoms from Loxosceles species of medical importance in Brazil. SDS-PAGE analysis showed variations in the composition of Loxosceles spp. and Sicarius ornatus venoms. Differences in the electrophoretic profiles of male and female venoms were also observed, indicating a possible intraspecific variation in the composition of the venom of Sicarius spider. The major component in all tested venoms had a Mr of 32-35 kDa, which was recognized by antiserum raised against Loxosceles SMases D. Moreover, male and female Sicarius ornatus spiders' venoms were able to hydrolyze sphingomyelin, thus showing an enzymatic activity similar to that determined for Loxosceles venoms. Sicarius ornatus venoms, as well as Loxosceles venoms, were able to render erythrocytes susceptible to lysis by autologous serum and to induce a significant loss of

  18. Aeromechanics of the Spider Cricket Jump: How to Jump 60+ Times Your Body Length and Still Land on Your Feet

    Science.gov (United States)

    Palmer, Emily; Deshler, Nicolas; Gorman, David; Neves, Catarina; Mittal, Rajat

    2015-11-01

    Flapping, gliding, running, crawling and swimming have all been studied extensively in the past and have served as a source of inspiration for engineering designs. In the current project, we explore a mode of locomotion that straddles ground and air: jumping. The subject of our study is among the most proficient of long-jumpers in Nature: the spider cricket of the family Rhaphidophoridae, which can jump more than 60 times its body length. Despite jumping this immense distance, these crickets usually land on their feet, indicating an ability to control their posture during ``flight.'' We employ high-speed videogrammetry, to examine the jumps and to track the crickets' posture and appendage orientation throughout their jumps. Simple aerodynamic models are developed to predict the aerodynamic forces and moment on the crickets during `flight`. The analysis shows that these wingless insects employ carefully controlled and coordinated positioning of the limbs during flight so as to increase jump distance and to stabilize body posture during flight. The principles distilled from this study could serve as an inspiration for small jumping robots that can traverse complex terrains.

  19. High-performance spider webs: integrating biomechanics, ecology and behaviour.

    Science.gov (United States)

    Harmer, Aaron M T; Blackledge, Todd A; Madin, Joshua S; Herberstein, Marie E

    2011-04-06

    Spider silks exhibit remarkable properties, surpassing most natural and synthetic materials in both strength and toughness. Orb-web spider dragline silk is the focus of intense research by material scientists attempting to mimic these naturally produced fibres. However, biomechanical research on spider silks is often removed from the context of web ecology and spider foraging behaviour. Similarly, evolutionary and ecological research on spiders rarely considers the significance of silk properties. Here, we highlight the critical need to integrate biomechanical and ecological perspectives on spider silks to generate a better understanding of (i) how silk biomechanics and web architectures interacted to influence spider web evolution along different structural pathways, and (ii) how silks function in an ecological context, which may identify novel silk applications. An integrative, mechanistic approach to understanding silk and web function, as well as the selective pressures driving their evolution, will help uncover the potential impacts of environmental change and species invasions (of both spiders and prey) on spider success. Integrating these fields will also allow us to take advantage of the remarkable properties of spider silks, expanding the range of possible silk applications from single threads to two- and three-dimensional thread networks.

  20. Reversible Myocarditis after Black Widow Spider Envenomation

    Directory of Open Access Journals (Sweden)

    Tarek Dendane

    2012-01-01

    Full Text Available Black widow spiders can cause variable clinical scenarios from local damage to very serious conditions including death. Acute myocardial damage is rarely observed and its prognostic significance is not known. We report a rare case of a 35-year-old man who developed an acute myocarditis with cardiogenic pulmonary edema requiring mechanical ventilation caused by black widow spider's envenomation. The patient was previously healthy. The clinical course was associated with systemic and cardiovascular complaints. His electrocardiogram revealed ST-segment elevation with T-wave amplitude. The plasma concentrations of cardiac enzymes were elevated. His first echocardiography showed hypokinesis of the left ventricle (left ventricle ejection fraction 48%. Magnetic resonance imaging showed also focal myocardial injury of the LV. There was progressive improvement in cardiac traces, biochemical and echocardiographical values (second left ventricle ejection fraction increased to 50%. Myocardial involvement after a spider bite is rare and can cause death. The exact mechanism of this myocarditis is unknown. We report a rare case of acute myocarditis with cardiogenic pulmonary edema requiring mechanical ventilation caused by black widow spider's envenomation. We objectively documented progressive clinical and electrical improvement.

  1. 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.

  2. Nutritional ecology: a first vegetarian spider.

    Science.gov (United States)

    Jackson, Duncan E

    2009-10-13

    Mutualisms are ubiquitous in nature and equally commonplace is their exploitation. A well-known mutualism has been found to be exploited from a surprising source: the first described vegetarian spider dines on trophic structures produced by acacia trees to reward their mutualistic protective ants.

  3. 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.

  4. Dreamcatcher, Gatekeeper, Spider Web, Safety Net.

    Science.gov (United States)

    Tweedie, Sanford; Madden, Marjorie

    1998-01-01

    Replicates, using diverse quotations grouped under four metaphors (dreamcatcher, gatekeeper, spider web, safety net) representing the dissonance of the reading/writing processes as they might be experienced by basic skills readers. Questions the relationship of basic skills to its students; implements D. Bartholomae's recommendations to reform of…

  5. The aerodynamic signature of running spiders.

    Science.gov (United States)

    Casas, Jérôme; Steinmann, Thomas; Dangles, Olivier

    2008-05-07

    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.

  6. Even the smallest non-crop habitat islands could be beneficial: distribution of carabid beetles and spiders in agricultural landscape.

    Science.gov (United States)

    Knapp, Michal; Řezáč, Milan

    2015-01-01

    Carabid beetles and ground-dwelling spiders inhabiting agroecosystems are beneficial organisms with a potential to control pest species. Intensification of agricultural management and reduction of areas covered by non-crop vegetation during recent decades in some areas has led to many potentially serious environmental problems including a decline in the diversity and abundance of beneficial arthropods in agricultural landscapes. This study investigated carabid beetle and spider assemblages in non-crop habitat islands of various sizes (50 to 18,000 square metres) within one large field, as well as the arable land within the field, using pitfall traps in two consecutive sampling periods (spring to early summer and peak summer). The non-crop habitat islands situated inside arable land hosted many unique ground-dwelling arthropod species that were not present within the surrounding arable land. Even the smallest non-crop habitat islands with areas of tens of square metres were inhabited by assemblages substantially different from these inhabiting arable land and thus enhanced the biodiversity of agricultural landscapes. The non-crop habitat area substantially affected the activity density, recorded species richness and recorded species composition of carabid and ground-dwelling spider assemblages; however, the effects were weakened when species specialised to non-crop habitats species were analysed separately. Interestingly, recorded species richness of spiders increased with non-crop habitat area, whereas recorded species richness of carabid beetles exhibited an opposite trend. There was substantial temporal variation in the spatial distribution of ground-dwelling arthropods, and contrasting patterns were observed for particular taxa (carabid beetles and spiders). In general, local environmental conditions (i.e., non-crop habitat island tree cover, shrub cover, grass cover and litter depth) were better determinants of arthropod assemblages than non-crop habitat island

  7. Salivary proteins of spider mites suppress defenses in Nicotiana benthamiana and promote mite reproduction.

    Science.gov (United States)

    Villarroel, Carlos A; Jonckheere, Wim; Alba, Juan M; Glas, Joris J; Dermauw, Wannes; Haring, Michel A; Van Leeuwen, Thomas; Schuurink, Robert C; Kant, Merijn R

    2016-04-01

    Spider mites (Tetranychidae sp.) are widely occurring arthropod pests on cultivated plants. Feeding by the two-spotted spider mite T. urticae, a generalist herbivore, induces a defense response in plants that mainly depends on the phytohormones jasmonic acid and salicylic acid (SA). On tomato (Solanum lycopersicum), however, certain genotypes of T. urticae and the specialist species T. evansi were found to suppress these defenses. This phenomenon occurs downstream of phytohormone accumulation via an unknown mechanism. We investigated if spider mites possess effector-like proteins in their saliva that can account for this defense suppression. First we performed an in silico prediction of the T. urticae and the T. evansi secretomes, and subsequently generated a short list of candidate effectors based on additional selection criteria such as life stage-specific expression and salivary gland expression via whole mount in situ hybridization. We picked the top five most promising protein families and then expressed representatives in Nicotiana benthamiana using Agrobacterium tumefaciens transient expression assays to assess their effect on plant defenses. Four proteins from two families suppressed defenses downstream of the phytohormone SA. Furthermore, T. urticae performance on N. benthamiana improved in response to transient expression of three of these proteins and this improvement was similar to that of mites feeding on the tomato SA accumulation mutant nahG. Our results suggest that both generalist and specialist plant-eating mite species are sensitive to SA defenses but secrete proteins via their saliva to reduce the negative effects of these defenses.

  8. Spit and venom from scytodes spiders: a diverse and distinct cocktail.

    Science.gov (United States)

    Zobel-Thropp, Pamela A; Correa, Sandra M; Garb, Jessica E; Binford, Greta J

    2014-02-01

    Spiders from the family Scytodidae have a unique prey capturing technique: they spit a zig-zagged silken glue to tether prey to a surface. Effectiveness of this sticky mixture is based on a combination of contraction and adhesion, trapping prey until the spider immobilizes it by envenomation and then feeds. We identify components expressed in Scytodes thoracica venom glands using combined transcriptomic and proteomic analyses. These include homologues of toxic proteins astacin metalloproteases and potentially toxic proteins including venom allergen, longistatin, and translationally controlled tumor protein (TCTP). We classify 19 distinct groups of candidate peptide toxins; 13 of these were detected in the venom, making up 35% of the proteome. Six have significant similarity to toxins from spider species spanning mygalomorph and nonhaplogyne araneomorph lineages, suggesting their expression in venom is phylogenetically widespread. Twelve peptide toxin groups have homologues in venom gland transcriptomes of other haplogynes. Of the transcripts, approximately 50% encode glycine-rich peptides that may contribute to sticky fibers in Scytodes spit. Fifty-one percent of the identified venom proteome is a family of proteins that is homologous to sequences from Drosophila sp. and Latrodectus hesperus with uncharacterized function. Characterization of these components holds promise for discovering new functional activity.

  9. Spider Bite: A Rare Case of Acute Necrotic Arachnidism with Rapid and Fatal Evolution

    Science.gov (United States)

    Giglio, Anna Maria; Scozzafava, Annamaria; Filippelli, Orazio; Serafino, Giuseppe; Verre, Mario

    2016-01-01

    The spider bites are quite frequent and often resolve quickly without leaving outcomes; only some species are capable of causing necrotic and systematic lesions in humans. Among them, we should mention the genus Loxosceles. The venom released from the spider bite of Loxosceles species is composed of proteins, enzymes, and nonenzymatic polypeptides. The phospholipase D family was identified as the active component of the venom. This family of enzymes is responsible for the local and systemic effects observed in loxoscelism. Phospholipases D interact with cell membranes triggering alterations which involve the complement system and activation of neutrophils and they cause the dermonecrotic skin lesions and systemic effects. We describe a fatal case of acute intoxication caused by a spider bite probably belonging to the species Loxosceles. The initial lesion was localized to a finger of a hand. Clinical course was worsening with deep necrotic lesions on limb, shock, hemolysis, acute kidney failure, and disseminated intravascular coagulation. All therapies were ineffective. This is the first fatal case described in Europe. PMID:27651958

  10. Spider Bite: A Rare Case of Acute Necrotic Arachnidism with Rapid and Fatal Evolution

    Directory of Open Access Journals (Sweden)

    Mario Pezzi

    2016-01-01

    Full Text Available The spider bites are quite frequent and often resolve quickly without leaving outcomes; only some species are capable of causing necrotic and systematic lesions in humans. Among them, we should mention the genus Loxosceles. The venom released from the spider bite of Loxosceles species is composed of proteins, enzymes, and nonenzymatic polypeptides. The phospholipase D family was identified as the active component of the venom. This family of enzymes is responsible for the local and systemic effects observed in loxoscelism. Phospholipases D interact with cell membranes triggering alterations which involve the complement system and activation of neutrophils and they cause the dermonecrotic skin lesions and systemic effects. We describe a fatal case of acute intoxication caused by a spider bite probably belonging to the species Loxosceles. The initial lesion was localized to a finger of a hand. Clinical course was worsening with deep necrotic lesions on limb, shock, hemolysis, acute kidney failure, and disseminated intravascular coagulation. All therapies were ineffective. This is the first fatal case described in Europe.

  11. Phantom spiders: notes on dubious spider species from Europe

    Directory of Open Access Journals (Sweden)

    Breitling, Rainer

    2015-11-01

    Full Text Available A surprisingly large number of European spider species have never been reliably rediscovered since their first description many decades ago. Most of these are probably synonymous with other species or unidentifiable, due to insufficient descriptions or missing type material. Here we discuss about 50 of these cases, declare some names as nomina dubia and establish the following new or re-confirmed synonymies: Agelena mengeella Strand, 1942 = Allagelena gracilens (C. L. Koch, 1841 syn. conf.; Anyphaena accentuata obscura (Sundevall, 1831 = Anyphaena accentuata (Walckenaer, 1802 syn. conf.; Anyphaena accentuata obscura Lebert, 1877 = Anyphaena accentuata (Walckenaer, 1802 syn. nov.; Araneus diadematus stellatus C. L. Koch, 1836 = Araneus diadematus Clerck, 1757 syn. nov.; Araneus diadematus islandicus (Strand, 1906 = Araneus diadematus Clerck, 1757 syn. nov.; Araneus quadratus minimus Simon, 1929 = Araneus quadratus Clerck, 1757 syn. nov.; Araneus quadratus subviridis (Franganillo, 1913 = Araneus quadratus Clerck, 1757 syn. nov.; Centromerus unctus (L. Koch, 1870 = Leptorhoptrum robustum (Westring, 1851 syn. nov.; Clubiona caliginosa Simon, 1932 = Clubiona germanica Thorell, 1871 syn. nov.; Coelotes atropos anomalus Hull, 1955 = Coelotes atropos (Walckenaer, 1830 syn. nov.; Coelotes atropos silvestris Hull, 1955 = Coelotes atropos (Walckenaer, 1830 syn. nov.; Coelotes obesus Simon, 1875 = Pireneitega pyrenaea (Simon, 1870 syn. conf.; Coelotes simoni Strand, 1907 = Coelotes solitarius (L. Koch, 1868 syn. nov.; Diplocephalus semiglobosus (Westring, 1861 nomen oblitum = Entelecara congenera (O. P.-Cambridge, 1879 syn. nov.; Drassodes voigti (Bösenberg, 1899 = Scotophaeus blackwalli (Thorell, 1871 syn. conf.; Erigone decens Thorell, 1871 = Hylyphantes graminicola (Sundevall, 1830 syn. nov.; Liocranoeca striata gracilior (Kulczynski, 1898 = Liocranoeca striata (Kulczynski, 1882 syn. conf.; Phlegra rogenhoferi (Simon, 1868 = Phlegra cinereofasciata

  12. Sphingomyelinase D in sicariid spider venom is a potent insecticidal toxin.

    Science.gov (United States)

    Zobel-Thropp, Pamela A; Kerins, Alec E; Binford, Greta J

    2012-09-01

    Spider venoms have evolved over hundreds of millions of years with a primary role of immobilizing prey. Sphingomyelinase D (SMase D) and homologs in the SicTox gene family are the most abundantly expressed toxic protein in venoms of Loxosceles and Sicarius spiders (Sicariidae). While SMase D is well known to cause dermonecrotic lesions in mammals, little work has investigated the bioactivity of this enzyme in its presumed natural role of immobilizing insect prey. We expressed and purified recombinant SMase D from Loxosceles arizonica (Laz-SMase D) and compared its enzymatic and insecticidal activity to that of crude venom. SMase D enzymatic activities of purified protein and crude venom from the same species were indistinguishable. In addition, SMase D and crude venom have comparable and high potency in immobilization assays on crickets. These data indicate that SMase D is a potent insecticidal toxin, the role for which it presumably evolved.

  13. Ctenus medius and Phoneutria nigriventer spiders venoms share noxious proinflammatory activities.

    Science.gov (United States)

    Okamoto, Cinthya Kimori; Gonçalves-De-Andrade, Rute M; Queiroz, Giselle Pidde; Gutierez, Vanessa P; De Almeida, Daniel Manzoni; Cury, Yara; Bertani, Rogério; Portaro, Fernanda C V; Tambourgi, Denise V

    2009-01-01

    Ctenus medius Keyserling, 1891 (Araneae: Ctenidae) co-occurs in various microhabitats of the Brazilian Atlantic Forest and can be easily misidentified as the medically important spider Phoneutria nigriventer Keyserling, 1981 (Ctenidae). Despite being phylogenetically close to Phoneutria, no data are available about the toxic potential of Ctenus medius venom. Here we show that, although presenting different profile of protein composition, C. medius venom displays some of the toxic properties exhibited by P. nigriventer venom, including proteolytic, hyaluronidasic and phospholipasic activities, as well as the ability of causing hyperalgesia and edema. Moreover, C. medius venom interferes in the activation of the complement system in concentrations that P. nigriventer venom is inactive. Thus, these data show that venoms of spiders from Ctenidae family share important proinflammatory properties and suggest that the C. medius bite may have an important noxious effect in human accidents.

  14. Multifunctional spider silk polymers for gene delivery to human mesenchymal stem cells.

    Science.gov (United States)

    Tokareva, Olena S; Glettig, Dean L; Abbott, Rosalyn D; Kaplan, David L

    2015-10-01

    Non-viral gene delivery systems are important transport vehicles that can be safe and effective alternatives to currently available viral systems. A new family of multifunctional spider silk-based gene carriers was bioengineered and found capable of targeting human mesenchymal stem cells (hMSCs). These carriers successfully delivered DNA to the nucleus of these mammalian cells. The presence of specific functional sequences in the recombinant proteins, such as a nuclear localization sequence (NLS) of the large tumor (T) antigen of the Simian virus 40 (SV40 ), an hMSC high affinity binding peptide (HAB), and a translocation motif (TLM) of the hepatitis-B virus surface protein (PreS2), and their roles in mitigation and enhancement of gene transfection efficiency towards hMSCs were characterized. The results demonstrate that these bioengineered spider silk proteins serve as effective carriers, without the well-known complications associated with viral delivery systems. © 2014 Wiley Periodicals, Inc.

  15. Spiders (Araneae of Hůrka u Hranic National Nature Reserve (Moravia, Czech Republic

    Directory of Open Access Journals (Sweden)

    Ondřej Machač

    2015-01-01

    Full Text Available Spiders of Hůrka u Hranic National Nature Reserve were investigated during the year 2011. Several capture methods were used during the vegetation season (from April to November in many various habitats of this territory. Altogether, 92 species from 27 families were recorded, including very rare and remarcable species. Majority of such species prefer thermophilous habitats: Atypus affinis Eichwald, 1830, Dysdera czechica Řezáč, in prep., Theridion melanurum Hahn, 1831, Agroeca cuprea Menge, 1873, Drassyllus villicus (Thorell, 1875, Zodarion germanicum (C. L. Koch, 1837 and Dipoena melanogaster (C. L. Koch, 1837. Some species are also listed in the Red List of threatened species in the Czech Republic: Cheiracanthium elegans Thorell, 1875 in category endangered (EN, Cozyptila blackwalli (Simon, 1875 and Leptorchestes berolinensis (C. L. Koch, 1846 in category vulnerable (VU. Altogether, 144 spider species are now known from the reserve; they represent 16.6% of araneofauna of the Czech Republic.

  16. Survival benefits select for group living in a social spider despite reproductive costs

    DEFF Research Database (Denmark)

    Bilde, T.; Coates, K.S.; Birkhofer, K.;

    2007-01-01

    The evolution of cooperation requires benefits of group living to exceed costs. Hence, some components of fitness are expected to increase with increasing group size, whereas others may decrease because of competition among group members. The social spiders provide an excellent system...... to investigate the costs and benefits of group living: they occur in groups of various sizes and individuals are relatively short-lived, therefore life history traits and Lifetime Reproductive Success (LRS) can be estimated as a function of group size. Sociality in spiders has originated repeatedly...... in phylogenetically distant families and appears to be accompanied by a transition to a system of continuous intra-colony mating and extreme inbreeding. The benefits of group living in such systems should therefore be substantial. We investigated the effect of group size on fitness components of reproduction...

  17. Status of the CNESM diagnostic for SPIDER

    Energy Technology Data Exchange (ETDEWEB)

    Muraro, A., E-mail: muraro@ifp.cnr.it [IFP-CNR, Via Cozzi 53, Milano (Italy); Croci, G. [IFP-CNR, Via Cozzi 53, Milano (Italy); Sez. INFN Milano-Bicocca, Piazza della Scienza 3, Milano (Italy); Albani, G. [University of Milano-Bicocca, Piazza della Scienza 3, Milano (Italy); Cazzaniga, C. [Sez. INFN Milano-Bicocca, Piazza della Scienza 3, Milano (Italy); University of Milano-Bicocca, Piazza della Scienza 3, Milano (Italy); Claps, G. [INFN-LNF, Via Enrico Fermi 40, Frascati (Italy); Cavenago, M. [INFN-LNL, Viale dell’Università 2, Legnaro (Italy); Grosso, G. [IFP-CNR, Via Cozzi 53, Milano (Italy); Palma, M. Dalla; Fincato, M. [RFX Consortium, Corso Stati uniti 4, Padova (Italy); Murtas, F. [INFN-LNF, Via Enrico Fermi 40, Frascati (Italy); Pasqualotto, R. [RFX Consortium, Corso Stati uniti 4, Padova (Italy); Cippo, E. Perelli [IFP-CNR, Via Cozzi 53, Milano (Italy); Rebai, M. [University of Milano-Bicocca, Piazza della Scienza 3, Milano (Italy); Sez. INFN Milano-Bicocca, Piazza della Scienza 3, Milano (Italy); Tollin, M. [RFX Consortium, Corso Stati uniti 4, Padova (Italy); Tardocchi, M. [IFP-CNR, Via Cozzi 53, Milano (Italy); Gorini, G. [University of Milano-Bicocca, Piazza della Scienza 3, Milano (Italy); Sez. INFN Milano-Bicocca, Piazza della Scienza 3, Milano (Italy)

    2015-10-15

    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.

  18. A checklist of spiders from Sovenga Hill, an inselberg in the Savanna Biome, Limpopo Province, South Africa (Arachnida: Araneae

    Directory of Open Access Journals (Sweden)

    M.A. Modiba

    2005-12-01

    Full Text Available The South African National Survey of Arachnida (SANSA was initiated to make an inventory of the arachnid fauna of South Africa. Various projects are underway to prepare inventories of the spider fauna of the different floral biomes and provinces of South Africa. During April and May 2004 five different collecting methods were sed to sample spiders from four slopes on Sovenga Hill, an inselberg situated in the Savanna Biome, near Polokwane, in the Limpopo Province of South Africa. A total of 793 specimens represented by 29 families, 62 genera and 76 species were recorded over the twomonth period. The Thomisidae was the most abundant (n = 167 representing 21.1 % of all spiders sampled, followed by the Gnaphosidae (n = 101 with 12.7 % and the Lycosidae (n = 77 with 9.7 %. The most abundant species was a thomisid Tmarus comellini Garcia-Neto (n = 82, representing 10.3 % of the total, followed by a clubionid Clubiona godfreyi Lessert (n = 66 with 8.3 %. The Thomisidae was the most species-rich family with 12 species, followed by the Gnaphosidae with 11 species and the Araneidae with 10 species. Of the species collected 83.9 % were wandering spiders and 16.1 % web builders. This is the first quantitative survey of the Savanna Biome in the Polokwane area.

  19. A Novel Neurotoxin from Venom of the Spider, Brachypelma albopilosum

    Science.gov (United States)

    Yuan, Mingwei; Li, Hongli; Wang, Ping; Yuan, Minglong; Lu, Qiumin

    2014-01-01

    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. PMID:25329070

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

    Science.gov (United States)

    Zhong, Yunhua; Song, Bo; Mo, Guoxiang; Yuan, Mingwei; Li, Hongli; Wang, Ping; Yuan, Minglong; Lu, Qiumin

    2014-01-01

    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. 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.

  2. Reconstructing web evolution and spider diversification in the molecular era.

    Science.gov (United States)

    Blackledge, Todd A; Scharff, Nikolaj; Coddington, Jonathan A; Szüts, Tamas; Wenzel, John W; Hayashi, Cheryl Y; Agnarsson, Ingi

    2009-03-31

    The evolutionary diversification of spiders is attributed to spectacular innovations in silk. Spiders are unique in synthesizing many different kinds of silk, and using silk for a variety of ecological functions throughout their lives, particularly to make prey-catching webs. Here, we construct a broad higher-level phylogeny of spiders combining molecular data with traditional morphological and behavioral characters. We use this phylogeny to test the hypothesis that the spider orb web evolved only once. We then examine spider diversification in relation to different web architectures and silk use. We find strong support for a single origin of orb webs, implying a major shift in the spinning of capture silk and repeated loss or transformation of orb webs. We show that abandonment of costly cribellate capture silk correlates with the 2 major diversification events in spiders (1). Replacement of cribellate silk by aqueous silk glue may explain the greater diversity of modern orb-weaving spiders (Araneoidea) compared with cribellate orb-weaving spiders (Deinopoidea) (2). Within the "RTA clade," which is the sister group to orb-weaving spiders and contains half of all spider diversity, >90% of species richness is associated with repeated loss of cribellate silk and abandonment of prey capture webs. Accompanying cribellum loss in both groups is a release from substrate-constrained webs, whether by aerially suspended webs, or by abandoning webs altogether. These behavioral shifts in silk and web production by spiders thus likely played a key role in the dramatic evolutionary success and ecological dominance of spiders as predators of insects.

  3. Thin Film Assembly of Spider Silk-like Block Copolymers

    Science.gov (United States)

    2011-01-01

    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...bioengineered variants of the spider silks , and stable monolayers were generated. Langmuir-Blodgett films were prepared by transferring the monolayers

  4. Turnover of Species and Guilds in Shrub Spider Communities in a 100-Year Postlogging Forest Chronosequence.

    Science.gov (United States)

    Haraguchi, Takashi F; Tayasu, Ichiro

    2016-02-01

    Disturbance of forests by logging and subsequent forest succession causes marked changes in arthropod communities. Although vegetation cover provides important habitat for arthropods, studies of the changes in their community structure associated with forest succession have been conducted mostly at ground level. To evaluate how forests of different ages contribute to arthropod biodiversity in shrub habitat, spiders were collected from shrubs in 12 forests ranging in age from 1 to 107 yr after logging. We found marked changes in spider community structure about 10 yr after logging: the number of species and individuals declined rapidly after this time. These changes were likely caused by a decrease in shrub cover in association with forest succession. Changes in spider species composition associated with stand age were small in forests at least 11 yr old and were not clustered by forest age. After the exclusion of species of which we sampled only one or two individuals incidentally, just 0.9 ± 0.5 (mean ± SD) species were unique to these older forests. The other 41.2 ± 4.3 species found in these forests were common to both older and young forests, although some of these species in common were found mainly in forests at least 11 yr old. These results suggest that preservation of old-growth forests contributes to the abundance of these common species, although old-growth forests contribute little to species diversity.

  5. A reconsideration of the classification of the spider infraorder Mygalomorphae (Arachnida: Araneae based on three nuclear genes and morphology.

    Directory of Open Access Journals (Sweden)

    Jason E Bond

    Full Text Available BACKGROUND: The infraorder Mygalomorphae (i.e., trapdoor spiders, tarantulas, funnel web spiders, etc. is one of three main lineages of spiders. Comprising 15 families, 325 genera, and over 2,600 species, the group is a diverse assemblage that has retained a number of features considered primitive for spiders. Despite an evolutionary history dating back to the lower Triassic, the group has received comparatively little attention with respect to its phylogeny and higher classification. The few phylogenies published all share the common thread that a stable classification scheme for the group remains unresolved. METHODS AND FINDINGS: We report here a reevaluation of mygalomorph phylogeny using the rRNA genes 18S and 28S, the nuclear protein-coding gene EF-1γ, and a morphological character matrix. Taxon sampling includes members of all 15 families representing 58 genera. The following results are supported in our phylogenetic analyses of the data: (1 the Atypoidea (i.e., antrodiaetids, atypids, and mecicobothriids is a monophyletic group sister to all other mygalomorphs; and (2 the families Mecicobothriidae, Hexathelidae, Cyrtaucheniidae, Nemesiidae, Ctenizidae, and Dipluridae are not monophyletic. The Microstigmatidae is likely to be subsumed into Nemesiidae. Nearly half of all mygalomorph families require reevaluation of generic composition and placement. The polyphyletic family Cyrtaucheniidae is most problematic, representing no fewer than four unrelated lineages. CONCLUSIONS: Based on these analyses we propose the following nomenclatural changes: (1 the establishment of the family Euctenizidae (NEW RANK; (2 establishment of the subfamily Apomastinae within the Euctenizidae; and (3 the transfer of the cyrtaucheniid genus Kiama to Nemesiidae. Additional changes include relimitation of Domiothelina and Theraphosoidea, and the establishment of the Euctenizoidina clade (Idiopidae + Euctenizidae. In addition to these changes, we propose a "road map

  6. Passive protections against breakdowns between accelerating grids in SPIDER experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pesce, Alberto, E-mail: alberto.pesce@igi.cnr.it [Consorzio RFX - Associazione EURATOM-ENEA per la fusione, Corso Stati Uniti 4, 35127, Padova (Italy); De Lorenzi, Antonio; Boldrin, Marco [Consorzio RFX - Associazione EURATOM-ENEA per la fusione, Corso Stati Uniti 4, 35127, Padova (Italy)

    2011-10-15

    In the SPIDER experiment a ITER-like full size plasma source will be realized with the target to extract a D{sup -} beam of 70 A and then to accelerate it to 100 keV energy. The reduction of the effects due to the frequent breakdowns between the accelerating grids is needed, because of grids damage due to energy deposition by arcing and strong electromagnetic noise (EMI) emission. The solution proposed is a comprehensive design of the circuit. Two passive components are installed: a Damping Resistor and an Output Filter in series to the Power Supplies. Then a doubled screened structure will be adopted for the 30 m long - 100 kV Transmission Line TL, which connects the Ion Source and Acceleration Power Supplies to their loads: the Inner Screen will be connected to the reference ground (the vessel) by a resistive link, the Outer Screen acting as a low-impedance ground. Finally, a Distributed Core Snubber DCS (magnetic snubber) will be installed onto the TL, aimed to increase the damping of the oscillations due to the stray inductances and capacitances. The DCS is composed of 10 magnetic alloy cores and is equipped by a biasing circuit to enhance the flux swing in unsaturated condition during the breakdown. A detailed model of the circuit is developed to evaluate the passive components parameters for protection against breakdown, in which all the magnetic and capacitive couplings between components are modeled as well as the magnetic core snubber saturation.

  7. Sublethal responses of wolf spiders (Lycosidae) to organophosphorous insecticides.

    Science.gov (United States)

    Van Erp, S; Booth, L; Gooneratne, R; O'Halloran, K

    2002-10-01

    The activities of cholinesterase (ChE) and glutathione S-transferase (GST) enzymes were assessed in the wolf spider (Lycosa hilaris) as biomarkers of organophosphate contamination in agricultural ecosystems. Spiders were exposed to simulated field rates of two commercially available organophosphorous insecticides [Basudin (diazinon) and Lorsban (chlorpyrifos)] under laboratory conditions. In terms of survival, chlorpyrifos and diazinon were more toxic to male than to female wolf spiders, but gender-specific differences in ChE activities were not evident. Cholinesterase activity in male spiders was inhibited to 14% and 61% of control activity by Basudin and Lorsban, respectively. Gluthathione S-transferase activity was not affected by either pesticide. Mortality and biomarker responses in the wolf spider were further investigated following the application of Basudin to pasture. Wolf spiders were deployed into field mesocosms; after 24 h mortality was 40%, and surviving spiders displayed significant inhibition of ChE activity (87%) compared with controls. Cholinesterase activity in spiders exposed for subsequent 24- or 48-h time periods was monitored until it returned to control levels 8 days post-application. Inhibition of ChE activity after a single application of Basudin indicate the potential use of this enzyme in wolf spiders as a biomarker for evaluating organophosphate contamination.

  8. Spider Silk as Guiding Biomaterial for Human Model Neurons

    National Research Council Canada - National Science Library

    Roloff, Frank; Strauß, Sarah; Vogt, Peter M; Bicker, Gerd; Radtke, Christine

    2014-01-01

    .... 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...

  9. Giant surface plasmon induced drag effect (SPIDEr) in metal nanowires

    Science.gov (United States)

    Durach, Maxim; Rusina, Anastasia; Stockman, Mark I.

    2009-08-01

    Here, for the first time we predict a giant surface plasmon-induced drag effect (SPIDEr), which exists under conditions of the extreme nanoplasmonic confinement. Under realistic conditions, in nanowires, this giant SPIDEr generates rectified THz potential differences up to 10 V and extremely strong electric fields up to ~ 105 ~ 106 V/cm. The SPIDEr is an ultrafast effect whose bandwidth for nanometric wires is ~ 20 THz. The giant SPIDEr opens up a new field of ultraintense THz nanooptics with wide potential applications in nanotechnology and nanoscience, including microelectronics, nanoplasmonics, and biomedicine.

  10. A novel property of spider silk: chemical defence against ants.

    Science.gov (United States)

    Zhang, Shichang; Koh, Teck Hui; Seah, Wee Khee; Lai, Yee Hing; Elgar, Mark A; Li, Daiqin

    2012-05-07

    Spider webs are made of silk, the properties of which ensure remarkable efficiency at capturing prey. However, remaining on, or near, the web exposes the resident spiders to many potential predators, such as ants. Surprisingly, ants are rarely reported foraging on the webs of orb-weaving spiders, despite the formidable capacity of ants to subdue prey and repel enemies, the diversity and abundance of orb-web spiders, and the nutritional value of the web and resident spider. We explain this paradox by reporting a novel property of the silk produced by the orb-web spider Nephila antipodiana (Walckenaer). These spiders deposit on the silk a pyrrolidine alkaloid (2-pyrrolidinone) that provides protection from ant invasion. Furthermore, the ontogenetic change in the production of 2-pyrrolidinone suggests that this compound represents an adaptive response to the threat of natural enemies, rather than a simple by-product of silk synthesis: while 2-pyrrolidinone occurs on the silk threads produced by adult and large juvenile spiders, it is absent on threads produced by small juvenile spiders, whose threads are sufficiently thin to be inaccessible to ants.

  11. 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.

  12. 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...

  13. Novel nanocomposites from spider silk–silica fusion (chimeric) proteins

    Science.gov (United States)

    Wong Po Foo, Cheryl; Patwardhan, Siddharth V.; Belton, David J.; Kitchel, Brandon; Anastasiades, Daphne; Huang, Jia; Naik, Rajesh R.; Perry, Carole C.; Kaplan, David L.

    2006-01-01

    Silica skeletal architectures in diatoms are characterized by remarkable morphological and nanostructural details. Silk proteins from spiders and silkworms form strong and intricate self-assembling fibrous biomaterials in nature. We combined the features of silk with biosilica through the design, synthesis, and characterization of a novel family of chimeric proteins for subsequent use in model materials forming reactions. The domains from the major ampullate spidroin 1 (MaSp1) protein of Nephila clavipes spider dragline silk provide control over structural and morphological details because it can be self-assembled through diverse processing methods including film casting and fiber electrospinning. Biosilica nanostructures in diatoms are formed in aqueous ambient conditions at neutral pH and low temperatures. The R5 peptide derived from the silaffin protein of Cylindrotheca fusiformis induces and regulates silica precipitation in the chimeric protein designs under similar ambient conditions. Whereas mineralization reactions performed in the presence of R5 peptide alone form silica particles with a size distribution of 0.5–10 μm in diameter, reactions performed in the presence of the new fusion proteins generate nanocomposite materials containing silica particles with a narrower size distribution of 0.5–2 μm in diameter. Furthermore, we demonstrate that composite morphology and structure could be regulated by controlling processing conditions to produce films and fibers. These results suggest that the chimeric protein provides new options for processing and control over silica particle sizes, important benefits for biomedical and specialty materials, particularly in light of the all aqueous processing and the nanocomposite features of these new materials. PMID:16769898

  14. Ecology of a bolas spider, Mastophora hutchinsoni: phenology, hunting tactics, and evidence for aggressive chemical mimicry.

    Science.gov (United States)

    Yeargan, Kenneth V

    1988-01-01

    Bolas spiders are relatively rare members of the large family known as orb weavers. Instead of using a typical web to capture prey, late-stadia and adult female bolas spiders swing a droplet of adhesive on a thread at flying insects. Mastophora hutchinsoni (Araneae: Araneidae) is one of five Mastophora species known from the United States and occurs over much of eastern North America. It is univoltine in Kentucky and overwinters in the egg stage. Spiderling emerged in May, the diminutive males matured in late June and early July, and females matured in early September. Eggs were produced from late September to late October or early November. This report is the first complete documentation of the population phenology of any bolas spider. Newly-emerged M. hutchinsoni spiderlings did not use a bolas, but instead hunted by positioning themselves on the underside of leaf margins where they ambushed small arthropods that crawled along the leaf margins. Subadult and adult female M. hutchinsoni used a bolas to capture moths. Only male moths were captured, specifically three species of Noctuidae (bristly cutworm, bronzed cutworm, and smoky tetanolita) and one species of Pyralidae (bluegrass webworm). Among 492 prey captured by more than twenty spiders at two sites during 1985 and 1986, smoky tetanolita moths and bristly cutworm moths accounted for 93% of the total. The flight behavior of approaching moths, the limited taxa caught from a large available moth fauna, and the fact that only males were caught support the hypothesis that the spider attracts its prey by producing chemicals which mimic the sex pheromones of these moth species. Adult female M. hutchinsoni frequently captured more than one moth species on a given night. The two most common prey species were active at different times of night, the bristly cutworm soon after nightfall and the smoky tetanolita generally between 11:00 p.m. and dawn. This pattern suggests that mating activity of these moth species may be

  15. Characterization of the SIRT family of NAD+-dependent protein deacetylases in the context of a mammalian model of hibernation, the thirteen-lined ground squirrel.

    Science.gov (United States)

    Rouble, Andrew N; Storey, Kenneth B

    2015-10-01

    Hibernating mammals employ strong metabolic rate depression to survive the winter, thereby avoiding the high energy costs of maintaining a euthermic lifestyle in the face of low seasonal temperatures and limited food resources. Characteristics of this natural torpor include a significant reduction in body temperature, a shift to a lipid-based metabolism, global suppression of ATP-expensive activities, and the upregulation of selected genes that mediate biochemical reorganization and cytoprotection. Sirtuin (SIRT) proteins, an evolutionarily conserved family of NAD(+)-dependent protein deacetylases, have been shown to play important roles in the post-translational regulation of many metabolic and cytoprotective processes, suggesting a potential function for these enzymes in the control of hibernation. To assess this possibility, protein levels of the seven mammalian SIRTs (SIRT1, SIRT2, SIRT3, SIRT4, SIRT5, SIRT6 and SIRT7), total SIRT activity, and the acetylation status of two downstream SIRT targets (SOD2K68 and NF-κB p65K310) were measured in skeletal muscle, liver, brown adipose and white adipose tissues of the hibernating thirteen-lined ground squirrel (Ictidomys tridecemlineatus) over the course of the torpor-arousal cycle. The analysis revealed tissue-specific responses of different SIRTs at various points throughout hibernation, including a potentially interesting correlation between increased levels of SIRT3 protein, heightened total SIRT activity, and decreased acetylation of SIRT3 downstream target SOD2K68 in skeletal muscle during late torpor. These results provide evidence to suggest a possible role for the SIRT family of protein deacetylases in the regulation of the metabolic and cellular protective pathways that mediate the process of mammalian hibernation.

  16. 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.

  17. 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.

  18. Poincar\\'{e} functions with spiders' webs

    CERN Document Server

    Mihaljević-Brandt, Helena

    2010-01-01

    For a polynomial p with a repelling fixed point w, we consider Poincar\\'{e} functions of p at w, i.e. entire functions L which satisfy L(0)=w and p(L(z))=L(p'(w)*z) for all z in the complex plane. We show that if the component of the Julia set of p that contains w equals {w}, then the (fast) escaping set of L is a spider's web; in particular it is connected. More precisely, we classify all linearizers of polynomials with regards to the spider's web structure of the set of all points which escape faster than the iterates of the maximum modulus function at a sufficiently large point.

  19. 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- 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.

  20. Virtual spiders raise real heart rates

    OpenAIRE

    2015-01-01

    Virtual realities (VR) give rise to feelings of presence in virtual environments and have been proven a useful medium when treating specific phobias. For validation of the usability of VR for exposure therapy it is critical to investigate the techs capacity of activating the user physiologically. An experiment was designed with the purpose of investigating if virtual spiders in a virtual environment could cause a heightening of heart rate in the participants (N = 24). The hypothesis was that ...

  1. Characterization of the venom from the Brazilian Brown Spider Loxosceles similis Moenkhaus, 1898 (Araneae, Sicariidae).

    Science.gov (United States)

    Silvestre, F G; de Castro, C S; de Moura, J F; Giusta, M S; De Maria, M; Alvares, E S S; Lobato, F C F; Assis, R A; Gonçalves, L A; Gubert, I C; Chávez-Olórtegui, C; Kalapothakis, E

    2005-12-15

    Accidents caused by brown spiders (Loxosceles genus) are frequent in Brazil and are associated with dermonecrotic lesions and, eventually, systemic reactions that may be lethal. The major species implicated with human envenoming have been: L. intermedia, L. gaucho and L. laeta. In this study we characterized the venom from Loxosceles similis, a species of spider normally found inside caves. L. similis venom was characterized by two-dimensional gel electrophoresis and enzymatic activity (dermonecrosis and haemolysis). The lethal dose to mice and the capacity of commercial anti-serum to neutralize this venom were also analysed. The cross-reactivity with anti-venoms against L. intermedia, L. laeta and L. gaucho were studied. Our results showed that this venom was able to induce severe dermonecrotic lesions and showed the presence of the bacteria Clostridium septicum in association with the fangs. In addition, we have cloned the DNA coding for a dermonecrotic protein (LsD1), using the genomic DNA of L. similis. The deduced amino acid sequence showed a toxin of approximately 31.2 kDa with an estimated pI of 7.37 and sequence similar to LiD1, a protein from the dermonecrotic family of Loxosceles intermedia spider venom, a synanthropic species of medical importance.

  2. Lamplighter groups, de Brujin graphs, spider-web graphs and their spectra

    Science.gov (United States)

    Grigorchuk, R.; Leemann, P.-H.; Nagnibeda, T.

    2016-05-01

    We study the infinite family of spider-web graphs \\{{{ S }}k,N,M\\}, k≥slant 2, N≥slant 0 and M≥slant 1, initiated in the 50s in the context of network theory. It was later shown in physical literature that these graphs have remarkable percolation and spectral properties. We provide a mathematical explanation of these properties by putting the spider-web graphs in the context of group theory and algebraic graph theory. Namely, we realize them as tensor products of the well-known de Bruijn graphs \\{{{ B }}k,N\\} with cyclic graphs \\{{C}M\\} and show that these graphs are described by the action of the lamplighter group {{ L }}k={Z}/k{Z}\\wr {Z} on the infinite binary tree. Our main result is the identification of the infinite limit of \\{{{ S }}k,N,M\\}, as N,M\\to ∞ , with the Cayley graph of the lamplighter group {{ L }}k which, in turn, is one of the famous Diestel-Leader graphs {{DL}}k,k. As an application we compute the spectra of all spider-web graphs and show their convergence to the discrete spectral distribution associated with the Laplacian on the lamplighter group.

  3. Spider-Venom Peptides as Bioinsecticides

    Directory of Open Access Journals (Sweden)

    Glenn F. King

    2012-03-01

    Full Text Available Over 10,000 arthropod species are currently considered to be pest organisms. They are estimated to contribute to the destruction of ~14% of the world’s annual crop production and transmit many pathogens. Presently, arthropod pests of agricultural and health significance are controlled predominantly through the use of chemical insecticides. Unfortunately, the widespread use of these agrochemicals has resulted in genetic selection pressure that has led to the development of insecticide-resistant arthropods, as well as concerns over human health and the environment. Bioinsecticides represent a new generation of insecticides that utilise organisms or their derivatives (e.g., transgenic plants, recombinant baculoviruses, toxin-fusion proteins and peptidomimetics and show promise as environmentally-friendly alternatives to conventional agrochemicals. Spider-venom peptides are now being investigated as potential sources of bioinsecticides. With an estimated 100,000 species, spiders are one of the most successful arthropod predators. Their venom has proven to be a rich source of hyperstable insecticidal mini-proteins that cause insect paralysis or lethality through the modulation of ion channels, receptors and enzymes. Many newly characterized insecticidal spider toxins target novel sites in insects. Here we review the structure and pharmacology of these toxins and discuss the potential of this vast peptide library for the discovery of novel bioinsecticides.

  4. Spider-venom peptides as bioinsecticides.

    Science.gov (United States)

    Windley, Monique J; Herzig, Volker; Dziemborowicz, Sławomir A; Hardy, Margaret C; King, Glenn F; Nicholson, Graham M

    2012-03-01

    Over 10,000 arthropod species are currently considered to be pest organisms. They are estimated to contribute to the destruction of ~14% of the world's annual crop production and transmit many pathogens. Presently, arthropod pests of agricultural and health significance are controlled predominantly through the use of chemical insecticides. Unfortunately, the widespread use of these agrochemicals has resulted in genetic selection pressure that has led to the development of insecticide-resistant arthropods, as well as concerns over human health and the environment. Bioinsecticides represent a new generation of insecticides that utilise organisms or their derivatives (e.g., transgenic plants, recombinant baculoviruses, toxin-fusion proteins and peptidomimetics) and show promise as environmentally-friendly alternatives to conventional agrochemicals. Spider-venom peptides are now being investigated as potential sources of bioinsecticides. With an estimated 100,000 species, spiders are one of the most successful arthropod predators. Their venom has proven to be a rich source of hyperstable insecticidal mini-proteins that cause insect paralysis or lethality through the modulation of ion channels, receptors and enzymes. Many newly characterized insecticidal spider toxins target novel sites in insects. Here we review the structure and pharmacology of these toxins and discuss the potential of this vast peptide library for the discovery of novel bioinsecticides.

  5. Host selection by a kleptobiotic spider

    Science.gov (United States)

    Hénaut, Yann; Delme, Juliette; Legal, Luc; Williams, Trevor

    2005-02-01

    Why do kleptobiotic spiders of the genus Argyrodes seem to be associated with spiders of the genus Nephila worldwide? Observations following introduction of experimental insect prey of different sizes and weights on to host webs revealed that: (1) small prey are more effectively retained on the web of Nephila clavipes than on the web of another common host, Leucauge venusta. (2) N. clavipes did not consume small prey that accumulated on the web whereas larger, heavier prey were enveloped and stored. (3) We observed clear partitioning of prey items between N. clavipes and Argyrodes spp.; diet selection by Argyrodes did not overlap with that of N. clavipes but closely overlapped with that of L. venusta. (4) L. venusta responds very quickly to prey impact whereas N. clavipes is slower, offering a temporal window of opportunity for Argyrodes foraging. (5) The ability of L. venusta to detect and respond to small items also means that it acts aggressively to Argyrodes spp., whereas N. clavipes does not. Consequently, food-acquisition behaviours of Argyrodes were clearly less risky with N. clavipes compared with L. venusta. We conclude that when a kleptobiotic organism has a choice of various host species, it will opt for the least risky host that presents the highest rate of availability of food items. The fact that Nephila species present such characteristics explains the worldwide association with Argyrodes kleptobiotic spiders.

  6. Spider-Venom Peptides as Bioinsecticides

    Science.gov (United States)

    Windley, Monique J.; Herzig, Volker; Dziemborowicz, Sławomir A.; Hardy, Margaret C.; King, Glenn F.; Nicholson, Graham M.

    2012-01-01

    Over 10,000 arthropod species are currently considered to be pest organisms. They are estimated to contribute to the destruction of ~14% of the world’s annual crop production and transmit many pathogens. Presently, arthropod pests of agricultural and health significance are controlled predominantly through the use of chemical insecticides. Unfortunately, the widespread use of these agrochemicals has resulted in genetic selection pressure that has led to the development of insecticide-resistant arthropods, as well as concerns over human health and the environment. Bioinsecticides represent a new generation of insecticides that utilise organisms or their derivatives (e.g., transgenic plants, recombinant baculoviruses, toxin-fusion proteins and peptidomimetics) and show promise as environmentally-friendly alternatives to conventional agrochemicals. Spider-venom peptides are now being investigated as potential sources of bioinsecticides. With an estimated 100,000 species, spiders are one of the most successful arthropod predators. Their venom has proven to be a rich source of hyperstable insecticidal mini-proteins that cause insect paralysis or lethality through the modulation of ion channels, receptors and enzymes. Many newly characterized insecticidal spider toxins target novel sites in insects. Here we review the structure and pharmacology of these toxins and discuss the potential of this vast peptide library for the discovery of novel bioinsecticides. PMID:22741062

  7. Molecular evolution of α-latrotoxin, the exceptionally potent vertebrate neurotoxin in black widow spider venom.

    Science.gov (United States)

    Garb, Jessica E; Hayashi, Cheryl Y

    2013-05-01

    Black widow spiders (members of the genus Latrodectus) are widely feared because of their potent neurotoxic venom. α-Latrotoxin is the vertebrate-specific toxin responsible for the dramatic effects of black widow envenomation. The evolution of this toxin is enigmatic because only two α-latrotoxin sequences are known. In this study, ~4 kb α-latrotoxin sequences and their homologs were characterized from a diversity of Latrodectus species, and representatives of Steatoda and Parasteatoda, establishing the wide distribution of latrotoxins across the mega-diverse spider family Theridiidae. Across black widow species, α-latrotoxin shows ≥ 94% nucleotide identity and variability consistent with purifying selection. Multiple codon and branch-specific estimates of the nonsynonymous/synonymous substitution rate ratio also suggest a long history of purifying selection has acted on α-latrotoxin across Latrodectus and Steatoda. However, α-latrotoxin is highly divergent in amino acid sequence between these genera, with 68.7% of protein differences involving non-conservative substitutions, evidence for positive selection on its physiochemical properties and particular codons, and an elevated rate of nonsynonymous substitutions along α-latrotoxin's Latrodectus branch. Such variation likely explains the efficacy of red-back spider, L. hasselti, antivenom in treating bites from other Latrodectus species, and the weaker neurotoxic symptoms associated with Steatoda and Parasteatoda bites. Long-term purifying selection on α-latrotoxin indicates its functional importance in black widow venom, even though vertebrates are a small fraction of their diet. The greater differences between Latrodectus and Steatoda α-latrotoxin, and their relationships to invertebrate-specific latrotoxins, suggest a shift in α-latrotoxin toward increased vertebrate toxicity coincident with the evolution of widow spiders.

  8. Silk gene expression of theridiid spiders: implications for male-specific silk use.

    Science.gov (United States)

    Correa-Garhwal, Sandra M; Chaw, R Crystal; Clarke, Thomas H; Ayoub, Nadia A; Hayashi, Cheryl Y

    2017-06-01

    Spiders (order Araneae) rely on their silks for essential tasks, such as dispersal, prey capture, and reproduction. Spider silks are largely composed of spidroins, members of a protein family that are synthesized in silk glands. As needed, silk stored in silk glands is extruded through spigots on the spinnerets. Nearly all studies of spider silks have been conducted on females; thus, little is known about male silk biology. To shed light on silk use by males, we compared silk gene expression profiles of mature males to those of females from three cob-web weaving species (Theridiidae). We de novo assembled species-specific male transcriptomes from Latrodectus hesperus, Latrodectus geometricus, and Steatoda grossa followed by differential gene expression analyses. Consistent with their complement of silk spigots, male theridiid spiders express appreciable amounts of aciniform, major ampullate, minor ampullate, and pyriform spidroin genes but not tubuliform spidroin genes. The relative expression levels of particular spidroin genes varied between sexes and species. Because mature males desert their prey-capture webs and become cursorial in their search for mates, we anticipated that major ampullate (dragline) spidroin genes would be the silk genes most highly expressed by males. Indeed, major ampullate spidroin genes had the highest expression in S. grossa males. However, minor ampullate spidroin genes were the most highly expressed spidroin genes in L. geometricus and L. hesperus males. Our expression profiling results suggest species-specific adaptive divergence of silk use by male theridiids. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  9. Chromosome mapping of dragline silk genes in the genomes of widow spiders (Araneae, Theridiidae.

    Directory of Open Access Journals (Sweden)

    Yonghui Zhao

    Full Text Available With its incredible strength and toughness, spider dragline silk is widely lauded for its impressive material properties. Dragline silk is composed of two structural proteins, MaSp1 and MaSp2, which are encoded by members of the spidroin gene family. While previous studies have characterized the genes that encode the constituent proteins of spider silks, nothing is known about the physical location of these genes. We determined karyotypes and sex chromosome organization for the widow spiders, Latrodectus hesperus and L. geometricus (Araneae, Theridiidae. We then used fluorescence in situ hybridization to map the genomic locations of the genes for the silk proteins that compose the remarkable spider dragline. These genes included three loci for the MaSp1 protein and the single locus for the MaSp2 protein. In addition, we mapped a MaSp1 pseudogene. All the MaSp1 gene copies and pseudogene localized to a single chromosomal region while MaSp2 was located on a different chromosome of L. hesperus. Using probes derived from L. hesperus, we comparatively mapped all three MaSp1 loci to a single region of a L. geometricus chromosome. As with L. hesperus, MaSp2 was found on a separate L. geometricus chromosome, thus again unlinked to the MaSp1 loci. These results indicate orthology of the corresponding chromosomal regions in the two widow genomes. Moreover, the occurrence of multiple MaSp1 loci in a conserved gene cluster across species suggests that MaSp1 proliferated by tandem duplication in a common ancestor of L. geometricus and L. hesperus. Unequal crossover events during recombination could have given rise to the gene copies and could also maintain sequence similarity among gene copies over time. Further comparative mapping with taxa of increasing divergence from Latrodectus will pinpoint when the MaSp1 duplication events occurred and the phylogenetic distribution of silk gene linkage patterns.

  10. Phenotypic integration in a series of trophic traits: tracing the evolution of myrmecophagy in spiders (Araneae).

    Science.gov (United States)

    Pekár, Stano; Michalko, Radek; Korenko, Stanislav; Sedo, Ondřej; Líznarová, Eva; Sentenská, Lenka; Zdráhal, Zbyněk

    2013-02-01

    Several hypotheses have been put forward to explain the evolution of prey specificity (stenophagy). Yet little light has so far been shed on the process of evolution of stenophagy in carnivorous predators. We performed a detailed analysis of a variety of trophic adaptations in one species. Our aim was to determine whether a specific form of stenophagy, myrmecophagy, has evolved from euryphagy via parallel changes in several traits from pre-existing characters. For that purpose, we studied the trophic niche and morphological, behavioural, venomic and physiological adaptations in a euryphagous spider, Selamia reticulata. It is a species that is branching off earlier in phylogeny than stenophagous ant-eating spiders of the genus Zodarion (both Zodariidae). The natural diet was wide and included ants. Laboratory feeding trials revealed versatile prey capture strategies that are effective on ants and other prey types. The performance of spiders on two different diets - ants only and mixed insects - failed to reveal differences in most fitness components (survival and developmental rate). However, the weight increase was significantly higher in spiders on the mixed diet. As a result, females on a mixed diet had higher fecundity and oviposited earlier. No differences were found in incubation period, hatching success or spiderling size. S. reticulata possesses a more diverse venom composition than Zodarion. Its venom is more effective for the immobilisation of beetle larvae than of ants. Comparative analysis of morphological traits related to myrmecophagy in the family Zodariidae revealed that their apomorphic states appeared gradually along the phylogeny to derived prey-specialised genera. Our results suggest that myrmecophagy has evolved gradually from the ancestral euryphagous strategy by integrating a series of trophic traits. Copyright © 2012 Elsevier GmbH. All rights reserved.

  11. High population density of black-handed spider monkeys (Ateles geoffroyi) in Costa Rican lowland wet forest.

    Science.gov (United States)

    Weghorst, Jennifer A

    2007-04-01

    The main objective of this study was to estimate the population density and demographic structure of spider monkeys living in wet forest in the vicinity of Sirena Biological Station, Corcovado National Park, Costa Rica. Results of a 14-month line-transect survey showed that spider monkeys of Sirena have one of the highest population densities ever recorded for this genus. Density estimates varied, however, depending on the method chosen to estimate transect width. Data from behavioral monitoring were available to compare density estimates derived from the survey, providing a check of the survey's accuracy. A combination of factors has most probably contributed to the high density of Ateles, including habitat protection within a national park and high diversity of trees of the fig family, Moraceae. Although natural densities of spider monkeys at Sirena are substantially higher than those recorded at most other sites and in previous studies at this site, mean subgroup size and age ratios were similar to those determined in previous studies. Sex ratios were similar to those of other sites with high productivity. Although high densities of preferred fruit trees in the wet, productive forests of Sirena may support a dense population of spider monkeys, other demographic traits recorded at Sirena fall well within the range of values recorded elsewhere for the species.

  12. A Comparative Analysis of the Venom Gland Transcriptomes of the Fishing Spiders Dolomedes mizhoanus and Dolomedes sulfurous.

    Directory of Open Access Journals (Sweden)

    Xunxun Xu

    Full Text Available Dolomedes sulfurous and Dolomedes mizhoanus are predaceous arthropods catching and feeding on small fish. They live in the same area and have similar habits. Their venoms exhibit some similarities and differences in biochemical and electrophysiological properties. In the present work, we first performed a transcriptomic analysis by constructing the venom gland cDNA library of D. sulfurous and 127 novel putative toxin sequences were consequently identified, which were classified into eight families. This venom gland transcriptome was then compared with that of D. mizhoanus, which revealed that the putative toxins from both spider venoms might have originated from the same gene ancestors although novel toxins were evolved independently in the two spiders. The putative toxins from both spiders contain 6-12 cysteine residues forming seven cysteine patterns. As revealed by blast search, the two venoms are rich in neurotoxins targeting ion channels with pharmacological and therapeutic significance. This study provides insight into the venoms of two closely related species of spider, which will be of use for future investigations into the structure and function of their toxins.

  13. A Comparative Analysis of the Venom Gland Transcriptomes of the Fishing Spiders Dolomedes mizhoanus and Dolomedes sulfurous.

    Science.gov (United States)

    Xu, Xunxun; Wang, Hengyun; Zhang, Fang; Hu, Zhaotun; Liang, Songping; Liu, Zhonghua

    2015-01-01

    Dolomedes sulfurous and Dolomedes mizhoanus are predaceous arthropods catching and feeding on small fish. They live in the same area and have similar habits. Their venoms exhibit some similarities and differences in biochemical and electrophysiological properties. In the present work, we first performed a transcriptomic analysis by constructing the venom gland cDNA library of D. sulfurous and 127 novel putative toxin sequences were consequently identified, which were classified into eight families. This venom gland transcriptome was then compared with that of D. mizhoanus, which revealed that the putative toxins from both spider venoms might have originated from the same gene ancestors although novel toxins were evolved independently in the two spiders. The putative toxins from both spiders contain 6-12 cysteine residues forming seven cysteine patterns. As revealed by blast search, the two venoms are rich in neurotoxins targeting ion channels with pharmacological and therapeutic significance. This study provides insight into the venoms of two closely related species of spider, which will be of use for future investigations into the structure and function of their toxins.

  14. 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...

  15. Fear of spiders: The effect of real threat on the interference caused by symbolic threat

    NARCIS (Netherlands)

    Kwakkenbos, C.M.C.; Becker, E.S.; Rinck, M.

    2010-01-01

    The effect of the presence of a real spider on attentional biases for symbolic spider stimuli was examined in 42 low-fearful and 26 high-spider-fearful participants. They completed a word colour-naming task as well as a picture orientation-judgement task, both with versus without a spider present in

  16. Comunidades de aranhas (Araneae em cultivos de seringueira (Hevea brasiliensis Muell. Arg. no Estado de São Paulo Spider communities (Araneae on rubber tree (Hevea brasiliensis Muell. Arg. plantations in São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Isabela Maria Piovesan Rinaldi

    2002-09-01

    Full Text Available The spider fauna composition of three rubber tree commercial plantations in the Northwest part of São Paulo State, Brazil, was characterized for both canopy and litter strata. On seven occasions from April 2000 to October 2001, samples were taken by beating sheet and hand capture, resulting in a total of 946 individuals, belonging to 24 families and 119 species. The most common species were Italaman santamaria Brescovit, 1997 and Teudis sp. (Anyphaenidae, Castianeira sp. and Falconina aff. gracilis (Corinnidae, Paracleocnemis sp. (Philodromidae, Ibotyporanga naideae Mello-Leitão, 1944 (Pholcidae, Chira spinipes (Taczanowiski, 1871 and Rudra sp. (Salticidae, Achaearanea hirta (Taczanowiski, 1873 and Coleosoma floridanum (Banks, 1900 (Theridiidae and Goeldia sp. (Titanoecidae. Anyphaenidae, Theridiidae and Salticidae were the most abundant families in the canopy, while Pholcidae and Corinnidae in the litter. Spider abundance was found to be, in general, positively correlated to the litter volume and density of branches in the trees. The use of acaricides and insecticides for one plantation resulted in a decrease in spider abundance for both strata. Abundance values among the samples suggest that the canopy spider abundance decreases with the loss of leaves in the dry season. Simultaneously, litter spider abundance increased in this season, because of the increase in litter volume. The most active canopy spiders, like runners and stalkers, should be investigated for their potential as pest control agents.

  17. A giant spider from the Jurassic of China reveals greater diversity of the orbicularian stem group

    Science.gov (United States)

    Selden, Paul A.; Shih, ChungKun; Ren, Dong

    2013-12-01

    A large female spider, Nephila jurassica, was described from Middle Jurassic strata of north-east China and placed in the modern genus Nephila (family Nephilidae) on the basis of many morphological similarities, but, as with many ancient fossils, the single specimen lacked synapomorphies of the family (Selden et al. 2011). In order to test the placement within the nephilid phylogenetic tree, Kuntner et al. (2013) calibrated the molecular phylogeny using N. jurassica in three different scenarios based on inferred mitochondrial substitution rates. They concluded that N. jurassica fitted better as a stem orbicularian than a nephilid. Now, a giant male spider has been discovered at the same locality that yielded N. jurassica. The two sexes are considered conspecific based on their similar morphological features, size, and provenance. The male cannot be accommodated in Nephilidae because of its pedipalp morphology, so the new genus Mongolarachne and family Mongolarachnidae are erected for the species. Comparison with possibly related families show that Mongolarachnidae is most likely on the orbicularian stem, close to other cribellate orbicularians (e.g., Deinopoidea), which suggests a greater diversity of cribellate orbicularians during the Middle Jurassic.

  18. Spiders as Potential Bio-Predators for Controlling Woodworm Infestation

    OpenAIRE

    Hippisley-Cox, Charles

    2012-01-01

    This study demonstrates that spiders may offer the ultimate green alternative for the control of woodworm. Following the use of a chemical spray a five year study of the relationship between Pholcus phalangioides and Anobium punctatum have generated some interesting observations and the suggestion that these spiders may also be used to tackle mosquitoes.

  19. Using Spider-Web Patterns To Determine Toxicity

    Science.gov (United States)

    Noever, David A.; Cronise, Raymond J.; Relwani, Rachna A.

    1995-01-01

    Method of determining toxicities of chemicals involves recording and analysis of spider-web patterns. Based on observation spiders exposed to various chemicals spin webs that differ, in various ways, from normal webs. Potential alternative to toxicity testing on higher animals.

  20. 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...

  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. Spiders (Araneae) in the pesticide world: an ecotoxicological review.

    Science.gov (United States)

    Pekár, Stano

    2012-11-01

    Being one of the most abundant and species-rich groups of natural enemies occurring in all agroecosystems, spiders are variably affected by pesticide applications. Here, a review is given of research on spider ecotoxicology. More than 40 species of spiders and almost 130 pesticides (acaricides, insecticides, fungicides and herbicides) have been tested so far in the field or under laboratory conditions. Field studies show that the degree of population reduction following pesticide application is a function of a number of factors inherent to pesticides, crops and spider species (guilds). These studies also revealed indirect effects via habitat and prey disruption. Among laboratory studies, a number of papers have investigated only the direct lethal effect. A meta-analysis of these data reveals that spiders are mainly affected by acaricides and insecticides, particularly neurotoxic substances. Currently, ecotoxicological research on spiders is focused more on direct sublethal effects on a variety of behavioural traits (locomotion, predation, web-building, reproduction, development) and physiology. Yet a standardised approach to the evaluation of sublethal effects is lacking. A few studies have provided some evidence for hormesis in spiders. Future research should be more concentrated on sublethal effects and the estimation of long-term changes in spider populations as a result of pesticide treatment. Copyright © 2012 Society of Chemical Industry.

  3. 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.

  4. 越南蜘蛛区系的初步研究(蛛形纲:蜘蛛目)%A Preliminary Note on Spider Fauna of Vietnam (Arachnida: Araneae)

    Institute of Scientific and Technical Information of China (English)

    范鼎飒; 徐湘; 李枢强

    2007-01-01

    The spider fauna of Vietnam are studied based on the examined specimens and related publications.A total of 320 spider species and one subspecies belonging to 32 families and 159 genera are known from Vietnam,including 21 species that are newly recorded to Vietnam in this study.%依据镜检标本和已知文献,初步研究了越南的蜘蛛区系.包括本文报道的21种新记录在内,越南蜘蛛目前已知320种及1亚种.

  5. The oldest haplogyne spider (Araneae: Plectreuridae), from the Middle Jurassic of China

    Science.gov (United States)

    Selden, Paul A.; Huang, Diying

    2010-05-01

    New fossil spiders (Arachnida: Araneae) from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China are described as Eoplectreurys gertschi gen. et sp. nov. and referred to the modern haplogyne family Plectreuridae. This small family is restricted to southwestern USA, Mexico, and the adjacent Caribbean area today and hitherto has only a sparse Cenozoic fossil record. The morphology of Eoplectreurys is remarkably similar to modern forms and thus demonstrates great evolutionary conservatism. This new discovery not only extends the fossil record of the family by at least 120 Ma to the Middle Jurassic but also supports the hypothesis of a different distribution of the family in the past than today and subsequent extinction over much of its former range.

  6. Recent advances in production of recombinant spider silk proteins.

    Science.gov (United States)

    Chung, Hannah; Kim, Tae Yong; Lee, Sang Yup

    2012-12-01

    Spider silk has been drawing much attention as a great biomaterial having many applications in biotechnology and biomedicine owing to its several desired material characteristics such as outstanding strength, toughness, and elasticity as well as biodegradability and biocompatibility. With various applications foreseeable in industry, there has been much effort to produce recombinant spider silk protein in large amounts. However, owing to the difficulties in its production using spiders, alternative host systems and engineering methods have been investigated to develop suitable production systems that can efficiently produce spider silk protein. Here, we review recent advances in production of spider silk proteins in various heterologous host systems with focus given on the development of metabolic and cellular engineering strategies. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. [Processing and Modification of Recombinant Spider Silk Proteins].

    Science.gov (United States)

    Liu, Bin; Wang, Tao; Liu, Xiaobing; Luo, Yongen

    2015-08-01

    Due to its special sequence structure, spider silk protein has unique physical and chemical properties, mechanical properties and excellent biological properties. With the expansion of the application value of spider silk in many fields as a functional material, progress has been made in the studies on the expression of recombinant spider silk proteins through many host systems by gene recombinant techniques. Recombinant spider silk proteins can be processed into high performance fibers, and a wide range of nonfibrous morphologies. Moreover, for their excellent biocompatibility and low immune response they are ideal for biomedical applications. Here we review the process and mechanism of preparation in vitro, chemistry and genetic engineering modification on recombinant spider silk protein.

  8. Biofabrication of cell-loaded 3D spider silk constructs.

    Science.gov (United States)

    Schacht, Kristin; Jüngst, Tomasz; Schweinlin, Matthias; Ewald, Andrea; Groll, Jürgen; Scheibel, Thomas

    2015-02-23

    Biofabrication is an emerging and rapidly expanding field of research in which additive manufacturing techniques in combination with cell printing are exploited to generate hierarchical tissue-like structures. Materials that combine printability with cytocompatibility, so called bioinks, are currently the biggest bottleneck. Since recombinant spider silk proteins are non-immunogenic, cytocompatible, and exhibit physical crosslinking, their potential as a new bioink system was evaluated. Cell-loaded spider silk constructs can be printed by robotic dispensing without the need for crosslinking additives or thickeners for mechanical stabilization. Cells are able to adhere and proliferate with good viability over at least one week in such spider silk scaffolds. Introduction of a cell-binding motif to the spider silk protein further enables fine-tuned control over cell-material interactions. Spider silk hydrogels are thus a highly attractive novel bioink for biofabrication. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Behavior of an adaptive bio-inspired spider web

    Science.gov (United States)

    Zheng, Lingyue; Behrooz, Majid; Huie, Andrew; Hartman, Alex; Gordaninejad, Faramarz

    2015-03-01

    The goal of this study is to demonstrate the feasibility of an artificial adaptive spider web with comparable behavior to a real spider web. First, the natural frequency and energy absorption ability of a passive web is studied. Next, a control system that consists of stepper motors, load cells and an Arduino, is constructed to mimic a spider's ability to control the tension of radial strings in the web. The energy related characteristics in the artificial spider web is examined while the pre-tension of the radial strings are varied. Various mechanical properties of a damaged spider web are adjusted to study their effect on the behavior of the web. It is demonstrated that the pre-tension and stiffness of the web's radial strings can significantly affect the natural frequency and the total energy of the full and damaged webs.

  10. 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...... 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...

  11. Male courtship vibrations delay predatory behaviour in female spiders.

    Science.gov (United States)

    Wignall, Anne E; Herberstein, Marie E

    2013-12-19

    During courtship, individuals transfer information about identity, mating status and quality. However, male web-building spiders face a significant problem: how to begin courting female spiders without being mistaken for prey? Male Argiope spiders generate distinctive courtship vibrations (shudders) when entering a female's web. We tested whether courtship shudders delay female predatory behaviour, even when live prey is present in the web. We presented a live cricket to females during playbacks of shudder vibrations, or white noise, and compared female responses to a control in which we presented a live cricket with no playback vibrations. Females were much slower to respond to crickets during playback of shudder vibrations. Shudder vibrations also delayed female predatory behaviour in a related spider species, showing that these vibrations do not simply function for species identity. These results suggest that male web-building spiders employ a phylogenetically conserved vibratory signal to ameliorate the risk of pre-copulatory cannibalism.

  12. Relatedness facilitates cooperation in the subsocial spider, Stegodyphus tentoriicola

    DEFF Research Database (Denmark)

    Ruch, Jasmin; Heinrich, Lisa; Bilde, T.;

    2009-01-01

    Background Cooperative hunting and foraging in spiders is rare and prone to cheating such that the actions of selfish individuals negatively affect the whole group. The resulting social dilemma may be mitigated by kin selection since related individuals lose indirect fitness benefits by acting...... selfishly. Indeed, cooperation with genetic kin reduces the disadvantages of within-group competition in the subsocial spider Stegodyphus lineatus, supporting the hypothesis that high relatedness is an important pre-adaptation in the transition to sociality in spiders. In this study we examined...... the consequences of group size and relatedness on cooperative feeding in the subsocial spider S. tentoriicola, a species suggested to be at the transition to permanent sociality. Results We formed groups of 3 and 6 spiders that were either siblings or non-siblings. We found that increasing group size negatively...

  13. Pervasive microRNA Duplication in Chelicerates: Insights from the Embryonic microRNA Repertoire of the Spider Parasteatoda tepidariorum.

    Science.gov (United States)

    Leite, Daniel J; Ninova, Maria; Hilbrant, Maarten; Arif, Saad; Griffiths-Jones, Sam; Ronshaugen, Matthew; McGregor, Alistair P

    2016-08-03

    MicroRNAs are small (∼22 nt) noncoding RNAs that repress translation and therefore regulate the production of proteins from specific target mRNAs. microRNAs have been found to function in diverse aspects of gene regulation within animal development and many other processes. Among invertebrates, both conserved and novel, lineage specific, microRNAs have been extensively studied predominantly in holometabolous insects such as Drosophila melanogaster However little is known about microRNA repertoires in other arthropod lineages such as the chelicerates. To understand the evolution of microRNAs in this poorly sampled subphylum, we characterized the microRNA repertoire expressed during embryogenesis of the common house spider Parasteatoda tepidariorum We identified a total of 148 microRNAs in P. tepidariorum representing 66 families. Approximately half of these microRNA families are conserved in other metazoans, while the remainder are specific to this spider. Of the 35 conserved microRNAs families 15 had at least two copies in the P. tepidariorum genome. A BLAST-based approach revealed a similar pattern of duplication in other spiders and a scorpion, but not among other chelicerates and arthropods, with the exception of a horseshoe crab. Among the duplicated microRNAs we found examples of lineage-specific tandem duplications, and the duplication of entire microRNA clusters in three spiders, a scorpion, and in a horseshoe crab. Furthermore, we found that paralogs of many P. tepidariorum microRNA families exhibit arm switching, which suggests that duplication was often followed by sub- or neofunctionalization. Our work shows that understanding the evolution of microRNAs in the chelicerates has great potential to provide insights into the process of microRNA duplication and divergence and the evolution of animal development.

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

    NARCIS (Netherlands)

    J. Huijding (Jorg); P.J. de Jong (Peter)

    2006-01-01

    textabstractThis 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. Th

  15. 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.

    2006-01-01

    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 t

  16. 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…

  17. 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.

  18. Structure of the yellow sac spider Cheiracanthium punctorium genes provides clues to evolution of insecticidal two-domain knottin toxins.

    Science.gov (United States)

    Sachkova, M Y; Slavokhotova, A A; Grishin, E V; Vassilevski, A A

    2014-08-01

    Yellow sac spiders (Cheiracanthium punctorium, family Miturgidae) are unique in terms of venom composition, because, as we show here, two-domain toxins have replaced the usual one-domain peptides as the major constituents. We report the structure of the two-domain Che. punctorium toxins (CpTx), along with the corresponding cDNA and genomic DNA sequences. At least three groups of insecticidal CpTx were identified, each consisting of several members. Unlike many cone snail and snake toxins, accelerated evolution is not typical of cptx genes, which instead appear to be under the pressure of purifying selection. Both CpTx modules present the inhibitor cystine knot (ICK), or knottin signature; however, the sequence similarity between the domains is low. Conversely, notable similarity was found between separate domains of CpTx and one-domain toxins from spiders of the Lycosidae family. The observed chimerism is a landmark of exon shuffling events, but in contrast to many families of multidomain protein genes no introns were found in the cptx genes. Considering the possible scenarios, we suggest that an early transcription-mediated fusion event between two related one-domain toxin genes led to the emergence of a primordial cptx-like sequence. We conclude that evolution of toxin variability in spiders appears to be quite different from other venomous animals.

  19. Isolation, N-glycosylations and Function of a Hyaluronidase-Like Enzyme from the Venom of the Spider Cupiennius salei.

    Directory of Open Access Journals (Sweden)

    Olivier Biner

    Full Text Available Hyaluronidases are important venom components acting as spreading factor of toxic compounds. In several studies this spreading effect was tested on vertebrate tissue. However, data about the spreading activity on invertebrates, the main prey organisms of spiders, are lacking. Here, a hyaluronidase-like enzyme was isolated from the venom of the spider Cupiennius salei. The amino acid sequence of the enzyme was determined by cDNA analysis of the venom gland transcriptome and confirmed by protein analysis. Two complex N-linked glycans akin to honey bee hyaluronidase glycosylations, were identified by tandem mass spectrometry. A C-terminal EGF-like domain was identified in spider hyaluronidase using InterPro. The spider hyaluronidase-like enzyme showed maximal activity at acidic pH, between 40-60°C, and 0.2 M KCl. Divalent ions did not enhance HA degradation activity, indicating that they are not recruited for catalysis.Besides hyaluronan, the enzyme degrades chondroitin sulfate A, whereas heparan sulfate and dermatan sulfate are not affected. The end products of hyaluronan degradation are tetramers, whereas chondroitin sulfate A is mainly degraded to hexamers. Identification of terminal N-acetylglucosamine or N-acetylgalactosamine at the reducing end of the oligomers identified the enzyme as an endo-β-N-acetyl-D-hexosaminidase hydrolase. The spreading effect of the hyaluronidase-like enzyme on invertebrate tissue was studied by coinjection of the enzyme with the Cupiennius salei main neurotoxin CsTx-1 into Drosophila flies. The enzyme significantly enhances the neurotoxic activity of CsTx-1. Comparative substrate degradation tests with hyaluronan, chondroitin sulfate A, dermatan sulfate, and heparan sulfate with venoms from 39 spider species from 21 families identified some spider families (Atypidae, Eresidae, Araneidae and Nephilidae without activity of hyaluronidase-like enzymes. This is interpreted as a loss of this enzyme and fits quite well

  20. The Transmission Line for the SPIDER experiment

    Energy Technology Data Exchange (ETDEWEB)

    Boldrin, Marco, E-mail: marco.boldrin@igi.cnr.it [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); De Lorenzi, Antonio; Recchia, Mauro; Toigo, Vanni [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Bonicelli, Tullio; Simon, Muriel [Fusion For Energy, c/o Josep Pla 2, 08019 Barcelona (Spain)

    2011-10-15

    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{sub 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.

  1. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    Science.gov (United States)

    Meirovitch, Sigal; Shtein, Zvi; Ben-Shalom, Tal; Lapidot, Shaul; Tamburu, Carmen; Hu, Xiao; Kluge, Jonathan A.; Raviv, Uri; Kaplan, David L.; Shoseyov, Oded

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites. PMID:27649169

  2. Mermithid parasitism of Hawaiian Tetragnatha spiders in a fragmented landscape

    Science.gov (United States)

    Vandergast, Amy; Roderick, George K.

    2003-01-01

    Hawaiian Tetragnatha spiders inhabiting small forest fragments on the Big Island of Hawaii are parasitized by mermithid nematodes. This is the first report of mermithid nematodes infecting spiders in Hawaii, and an initial attempt to characterize this host–parasite interaction. Because immature mermithids were not morphologically identifiable, a molecular identification was performed. A phylogenetic analysis based on 18S small ribosomal subunit nuclear gene sequences suggested that Hawaiian spider mermithids are more closely related to a mainland presumptive Aranimemis species that infects spiders, than to an insect-infecting mermithid collected on Oahu, HI, or to Mermis nigrescens, also a parasite of insects. Measured infection prevalence was low (ranging from 0 to 4%) but differed significantly among forest fragments. Infection prevalence was associated significantly with fragment area, but not with spider density nor spider species richness. Results suggest that mermithid populations are sensitive to habitat fragmentation, but that changes in infection prevalence do not appear to affect spider community structure.

  3. First investigation of spider silk as a braided microsurgical suture.

    Science.gov (United States)

    Kuhbier, Joern W; Reimers, Kerstin; Kasper, Cornelia; Allmeling, Christina; Hillmer, Anja; Menger, Björn; Vogt, Peter M; Radtke, Christine

    2011-05-01

    Inhibition of axonal outgrowth accompanied by neuroma formation appears in microsurgical nerve repair as reaction to common microsuture materials like silk, nylon, or polyglycolic acid. In contrast, recent findings revealed advantages of spider silk fibers in guiding Schwann cells in nerve regeneration. Here, we asked if we could braid microsutures from native spider silk fibers. Microsutures braided of native spider dragline silk were manufactured, containing either 2 × 15 or 3 × 10 single fibres strands. Morphologic appearance was studied and tensile strength and stress-strain ratio (SSR) were calculated. The constructed spider silk sutures showed a median thickness of 25 μm, matching the USP definition of 10-0. Maximum load and tensile strength for both spider silk microsutures were significantly more than 2-fold higher than for nylon suture; SSR was 1.5-fold higher. All values except elasticity were higher in 3 × 10 strand sutures compared to 2 × 15 strand sutures, but not significantly. In this pilot study, we demonstrate the successful manufacture of microsutures from spider silk. With regards to the mechanical properties, these sutures were superior to nylon sutures. As spider silk displays high biocompatibility in nerve regeneration, its usage in microsurgical nerve repair should be considered. Copyright © 2011 Wiley Periodicals, Inc.

  4. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly.

    Science.gov (United States)

    Meirovitch, Sigal; Shtein, Zvi; Ben-Shalom, Tal; Lapidot, Shaul; Tamburu, Carmen; Hu, Xiao; Kluge, Jonathan A; Raviv, Uri; Kaplan, David L; Shoseyov, Oded

    2016-09-18

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites.

  5. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    Directory of Open Access Journals (Sweden)

    Sigal Meirovitch

    2016-09-01

    Full Text Available The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs and recombinant spider silk protein fused to a cellulose binding domain (CBD is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS, small angle X-ray scattering (SAXS and cryo-transmission electron microscopy (TEM indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites.

  6. 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.

  7. Probing the Impact of Acidification on Spider Silk Assembly Kinetics.

    Science.gov (United States)

    Xu, Dian; Guo, Chengchen; Holland, Gregory P

    2015-07-13

    Spiders utilize fine adjustment of the physicochemical conditions within its silk spinning system to regulate spidroin assembly into solid silk fibers with outstanding mechanical properties. However, the exact mechanism about which this occurs remains elusive and is still hotly debated. In this study, the effect of acidification on spider silk assembly was investigated on native spidroins from the major ampullate (MA) gland fluid excised from Latrodectus hesperus (Black Widow) spiders. Incubating the protein-rich MA silk gland fluid at acidic pH conditions results in the formation of silk fibers that are 10-100 μm in length and ∼2 μm in diameter as judged by optical and electron microscope methods. The in vitro spider silk assembly kinetics were monitored as a function of pH with a (13)C solid-state MAS NMR approach. The results confirm the importance of acidic pH in the spider silk self-assembly process with observation of a sigmoidal nucleation-elongation kinetic profile. The rates of nucleation and elongation as well as the percentage of β-sheet structure in the grown fibers depend on the pH. These results confirm the importance of an acidic pH gradient along the spinning duct for spider silk formation and provide a powerful spectroscopic approach to probe the kinetics of spider silk formation under various biochemical conditions.

  8. Spider orientation and hub position in orb webs

    Science.gov (United States)

    Zschokke, Samuel; Nakata, Kensuke

    2010-01-01

    Orb-web building spiders (Araneae: Araneoidea, Uloboridae) can be considered as territorial central place foragers. In territorial central place foragers, the optimal foraging arena is circular, with the forager sitting in its centre. In orb webs, the spider’s orientation (head up or head down) whilst waiting for prey on the hub of its web and the downwards-upwards asymmetry of its running speeds are the probable causes for the observed deviation of the hub from the web’s centre. Here, we present an analytical model and a more refined simulation model to analyse the relationships amongst the spider’s running speeds, its orientation whilst waiting for prey and the vertical asymmetry of orb webs. The results of our models suggest that (a) waiting for prey head down is generally favourable because it allows the spider to reach the prey in its web on average quicker than spiders waiting head up, (b) the downwards-upwards running speed asymmetry, together with the head-down orientation of most spiders, are likely causes for the observed vertical asymmetry of orb webs, (c) waiting head up can be advantageous for spiders whose downwards-upwards running speed asymmetry is small and who experience high prey tumbling rates and (d) spiders waiting head up should place their hub lower than similar spiders waiting head down.

  9. 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.

  10. Structural and optical studies on selected web spinning spider silks

    Science.gov (United States)

    Karthikeyani, R.; Divya, A.; Mathavan, T.; Asath, R. Mohamed; Benial, A. Milton Franklin; Muthuchelian, K.

    2017-01-01

    This study investigates the structural and optical properties in the cribellate silk of the sheet web spider Stegodyphus sarasinorum Karsch (Eresidae) and the combined dragline, viscid silk of the orb-web spiders Argiope pulchella Thorell (Araneidae) and Nephila pilipes Fabricius (Nephilidae). X-ray diffraction (XRD), Fourier transform infra-red (FTIR), Ultraviolet-visible (UV-Vis) and fluorescence spectroscopic techniques were used to study these three spider silk species. X-ray diffraction data are consistent with the amorphous polymer network which is arising from the interaction of larger side chain amino acid contributions due to the poly-glycine rich sequences known to be present in the proteins of cribellate silk. The same amorphous polymer networks have been determined from the combined dragline and viscid silk of orb-web spiders. From FTIR spectra the results demonstrate that, cribellate silk of Stegodyphus sarasinorum, combined dragline viscid silk of Argiope pulchella and Nephila pilipes spider silks are showing protein peaks in the amide I, II and III regions. Further they proved that the functional groups present in the protein moieties are attributed to α-helical and side chain amino acid contributions. The optical properties of the obtained spider silks such as extinction coefficients, refractive index, real and imaginary dielectric constants and optical conductance were studied extensively from UV-Vis analysis. The important fluorescent amino acid tyrosine is present in the protein folding was investigated by using fluorescence spectroscopy. This research would explore the protein moieties present in the spider silks which were found to be associated with α-helix and side chain amino acid contributions than with β-sheet secondary structure and also the optical relationship between the three different spider silks are investigated. Successful spectroscopic knowledge of the internal protein structure and optical properties of the spider silks could

  11. Behavioural and biomaterial coevolution in spider orb webs.

    Science.gov (United States)

    Sensenig, A; Agnarsson, I; Blackledge, T A

    2010-09-01

    Mechanical performance of biological structures, such as tendons, byssal threads, muscles, and spider webs, is determined by a complex interplay between material quality (intrinsic material properties, larger scale morphology) and proximate behaviour. Spider orb webs are a system in which fibrous biomaterials--silks--are arranged in a complex design resulting from stereotypical behavioural patterns, to produce effective energy absorbing traps for flying prey. Orb webs show an impressive range of designs, some effective at capturing tiny insects such as midges, others that can occasionally stop even small birds. Here, we test whether material quality and behaviour (web design) co-evolve to fine-tune web function. We quantify the intrinsic material properties of the sticky capture silk and radial support threads, as well as their architectural arrangement in webs, across diverse species of orb-weaving spiders to estimate the maximum potential performance of orb webs as energy absorbing traps. We find a dominant pattern of material and behavioural coevolution where evolutionary shifts to larger body sizes, a common result of fecundity selection in spiders, is repeatedly accompanied by improved web performance because of changes in both silk material and web spinning behaviours. Large spiders produce silk with improved material properties, and also use more silk, to make webs with superior stopping potential. After controlling for spider size, spiders spinning higher quality silk used it more sparsely in webs. This implies that improvements in silk quality enable 'sparser' architectural designs, or alternatively that spiders spinning lower quality silk compensate architecturally for the inferior material quality of their silk. In summary, spider silk material properties are fine-tuned to the architectures of webs across millions of years of diversification, a coevolutionary pattern not yet clearly demonstrated for other important biomaterials such as tendon, mollusc

  12. INTERVENTION PROGRAM FOR NURSING STAFF REGARDING APPROACH TO A PATIENT WITH SPIDER PHOBIA AND/OR BITE.

    Science.gov (United States)

    Al-Agroudi, Mahfouz Ahmad; Ahmed, Salwa Abdalla Mohammad; Morsy, Tosson A

    2016-04-01

    Spider bites are uncommon medical events, since there are limited number of spiders world-wide with fangs strong enough to pierce human skin, and most spiders bite humans only as a final defense when being crushed between skin and another object. Thus, most lesions attributed to spider bites are caused by some other etiology. The spiders that can cause medically significant bites include widow and false widow spiders (worldwide), recluse spiders (mostly North and South America), Australian funnel web spiders (eastern coastal Australia) and Phoneutria spiders (Brazil). Acute spider bites most commonly result in a solitary papule, pustule, or wheal. Systemic symptoms can accompany envenomation of widow; funnel web, and Phoneutria spiders, and less often, those of recluse spiders.

  13. Diversity and community assembly patterns of epigean vs. troglobiont spiders in the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Cardoso Pedro

    2012-01-01

    Full Text Available Cave-obligate organisms usually have smaller ranges and their assemblages have higher beta diversity than their epigean counterparts. Phylogenetic and functional diversity is usually low in cave communities, leading to taxonomic and functional disharmony, with entire groups missing from the subterranean realm. The objective of this work is to compare range, beta diversity, phylogenetic and functional diversity, taxonomic and functional disharmony of epigean versus troglobiont spiders in the Iberian Peninsula. The median extent of occurrence was found to be 33 times higher for epigean than for cave species. Beta diversity was significantly higher for troglobiont assemblages. Cave assemblages present lower phylogenetic and functional diversities than expected by chance. Taxonomic disharmony was noticeable, with many speciose families, namely Gnaphosidae, Salticidae and Lycosidae, absent in caves. Functional disharmony was equally high, with ambush hunters and sensing web weavers being absent in caves. The small range and high beta diversity of troglobiont spiders in the Iberian Peninsula is typical of many cave-obligate organisms, caused by the fragmentation and isolation of cave systems and the low vagility and high habitat specialization of species. Caves were colonized mainly by pre-adapted lineages, with high proportions of eutroglophile species. Some families no longer occur in surface habitats, possibly since the last glaciations, and currently are restricted to caves in the region. Few hunting strategies and web types are efficient in caves and these dominate among the troglobiont species. As troglobiont communities are of low alpha diversity, with low functional redundancy, have narrow ranges, present high levels of population fragmentation and are taxonomically unique, they should present higher proportions of imperilled species than epigean spiders in the Iberian Peninsula. Some species are probably endangered and require urgent

  14. Structure-Function-Property-Design Interplay in Biopolymers: Spider Silk

    Science.gov (United States)

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

    2013-01-01

    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. PMID:23962644

  15. 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...... 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...

  16. Spider silk: a novel optical fibre for biochemical sensing

    Science.gov (United States)

    Hey Tow, Kenny; Chow, Desmond M.; Vollrath, Fritz; Dicaire, Isabelle; Gheysens, Tom; Thévenaz, Luc

    2015-09-01

    Whilst being thoroughly used in the textile industry and biomedical sector, silk has not yet been exploited for fibre optics-based sensing although silk fibres directly obtained from spiders can guide light and have shown early promises to being sensitive to some solvents. In this communication, a pioneering optical fibre sensor based on spider silk is reported, demonstrating for the first time the use of spider silk as an optical fibre sensor to detect polar solvents such as water, ammonia and acetic acid.

  17. 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.

  18. 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.

  19. Misdiagnosis of spider bites: bacterial associates, mechanical pathogen transfer, and hemolytic potential of venom from the hobo spider, Tegenaria agrestis (Araneae: Agelenidae).

    Science.gov (United States)

    Gaver-Wainwright, Melissa M; Zack, Richard S; Foradori, Matthew J; Lavine, Laura Corley

    2011-03-01

    The European spider Tegenaria agrestis (Walckenaer) (hobo spider) has been implicated as a spider of medical importance in the Pacific Northwest since its introduction in the late 1980s. Studies have indicated that the hobo spider causes necrotic tissue lesions through hemolytic venom or through the transfer of pathogenic bacteria introduced by its bite. Bacterial infections are often diagnosed as spider bites, in particular the pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA). This study examines three aspects of the potential medical importance of hobo spiders in part of its introduced range, Washington State. First, the bacterial diversity of the spider was surveyed using a polymerase chain reaction-based assay to determine whether the spider carries any pathogenic bacteria. Second, an experiment was conducted to determine the ability of the spiders to transfer MRSA. Third, the venom was evaluated to assess the hemolytic activity. We found 10 genera of ubiquitous bacteria on the exterior surface of the spiders. In addition, none of the spiders exposed to MRSA transferred this pathogen. Finally, the hemolytic venom assay corroborates previous studies that found hobo spider venom was not deleterious to vertebrate red blood cells.

  20. 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.

  1. 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.

  2. 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.

  3. Characterization of a Gene Coding for the Complement System Component FB from Loxosceles laeta Spider Venom Glands.

    Directory of Open Access Journals (Sweden)

    Daniela Tiemi Myamoto

    Full Text Available The human complement system is composed of more than 30 proteins and many of these have conserved domains that allow tracing the phylogenetic evolution. The complement system seems to be initiated with the appearance of C3 and factor B (FB, the only components found in some protostomes and cnidarians, suggesting that the alternative pathway is the most ancient. Here, we present the characterization of an arachnid homologue of the human complement component FB from the spider Loxosceles laeta. This homologue, named Lox-FB, was identified from a total RNA L. laeta spider venom gland library and was amplified using RACE-PCR techniques and specific primers. Analysis of the deduced amino acid sequence and the domain structure showed significant similarity to the vertebrate and invertebrate FB/C2 family proteins. Lox-FB has a classical domain organization composed of a control complement protein domain (CCP, a von Willebrand Factor domain (vWFA, and a serine protease domain (SP. The amino acids involved in Mg2+ metal ion dependent adhesion site (MIDAS found in the vWFA domain in the vertebrate C2/FB proteins are well conserved; however, the classic catalytic triad present in the serine protease domain is not conserved in Lox-FB. Similarity and phylogenetic analyses indicated that Lox-FB shares a major identity (43% and has a close evolutionary relationship with the third isoform of FB-like protein (FB-3 from the jumping spider Hasarius adansoni belonging to the Family Salcitidae.

  4. Characterization of a Gene Coding for the Complement System Component FB from Loxosceles laeta Spider Venom Glands.

    Science.gov (United States)

    Myamoto, Daniela Tiemi; Pidde-Queiroz, Giselle; Gonçalves-de-Andrade, Rute Maria; Pedroso, Aurélio; van den Berg, Carmen W; Tambourgi, Denise V

    2016-01-01

    The human complement system is composed of more than 30 proteins and many of these have conserved domains that allow tracing the phylogenetic evolution. The complement system seems to be initiated with the appearance of C3 and factor B (FB), the only components found in some protostomes and cnidarians, suggesting that the alternative pathway is the most ancient. Here, we present the characterization of an arachnid homologue of the human complement component FB from the spider Loxosceles laeta. This homologue, named Lox-FB, was identified from a total RNA L. laeta spider venom gland library and was amplified using RACE-PCR techniques and specific primers. Analysis of the deduced amino acid sequence and the domain structure showed significant similarity to the vertebrate and invertebrate FB/C2 family proteins. Lox-FB has a classical domain organization composed of a control complement protein domain (CCP), a von Willebrand Factor domain (vWFA), and a serine protease domain (SP). The amino acids involved in Mg2+ metal ion dependent adhesion site (MIDAS) found in the vWFA domain in the vertebrate C2/FB proteins are well conserved; however, the classic catalytic triad present in the serine protease domain is not conserved in Lox-FB. Similarity and phylogenetic analyses indicated that Lox-FB shares a major identity (43%) and has a close evolutionary relationship with the third isoform of FB-like protein (FB-3) from the jumping spider Hasarius adansoni belonging to the Family Salcitidae.

  5. Family physicians' effort to stay in charge of the medical treatment when patients have home care by district nurses. A grounded theory study

    Directory of Open Access Journals (Sweden)

    Hylander Ingrid

    2009-06-01

    Full Text Available Abstract Background District nurses (DNs provide home care for old persons with a mixture of chronic diseases, symptoms and reduced functional ability. Family physicians (FPs have been criticised for their lack of involvement in this care. The aim of this study was to obtain increased knowledge concerning the FP's experience of providing medical treatment for patients with home care provided by DNs by developing a theoretical model that elucidates how FPs handle the problems they encounter regarding the individual patients and their conditions. Methods Semi-structured interviews were conducted with 13 Swedish FPs concerning one of their registered patients with home care by a DN, and the treatment of this patient. Grounded theory methodology (GTM was used in the analyses. Results The core category was the effort to stay in charge of the medical treatment. This involved three types of problems: gaining sufficient insight, making adequate decisions, and maintaining appropriate medical treatment. For three categories of patients, the FPs had problems staying in charge. Patients with reduced functional ability had problems providing information and maintaining treatment. Patients who were "fixed in their ways" did not provide information and did not comply with recommendations, and for patients with complex conditions, making adequate decisions could be problematic. To overcome the problems, four different strategies were used: relying on information from others, supporting close observation and follow-up by others, being constantly ready to change the goal of the treatment, and relying on others to provide treatment. Conclusion The patients in this study differed from most other patients seen at the healthcare centre as the consultation with the patient could not provide the usual foundation for decisions concerning medical treatment. Information from and collaboration with the DN and other home care providers was essential for the FP's effort to

  6. A Check-List of the Spiders (Araneae) of the Bolshekhekhtsyrski Nature Reserve, Khabarovsk Province, the Russian Far East

    Institute of Scientific and Technical Information of China (English)

    Yuri M. Marusik; Andrei V. Tanasevitch; Dmitri K. Kurenshchikov; Dmitri V. Logunov

    2007-01-01

    326 species of spiders belonging to 26 families are recorded from the Bolshekhekhtsyrski State Nature Reserve, of them 70 are new records for the reserve and six are new to the fauna of Russia: Asperthorox boreolis Ono et Saito, 2001; Cyclosa kumadai Tanikawa, 1992; Cyclosa okumae Tanikawa, 1992(earlier it was identified as C. argenteoalba Bbsenberg et Strand, 1906); Haplodrassus taepaikensis Paik, 1992; Hypselistes fossilobus Fei et Zhu, 1993; and Pachygnatha gaoi Zhu et al., 2003. The name Pronous minutus (S. Saito, 1939) is synonymized with Pronoides brunneus Schenkel, 1936. The male of H. taepaikensis is illustrated for the first time. Composition of the fauna is briefly discussed; 41% of the recorded species have their ranges confined to the SE Palaearctics. By its species diversity, the reserve' s fauna is the second largest local fauna eastward of the Urals. An expected spider diversity of this reserve is likely to be over 400 species.

  7. Molecular spring: from spider silk to silkworm silk

    CERN Document Server

    Wu, Xiang; Du, Ning; Xu, Gang-Qin; Li, Bao-Wen

    2009-01-01

    In this letter, we adopt a new approach combining theoretical modeling with silk stretching measurements to explore the mystery of the structures between silkworm and spider silks, leading to the differences in mechanical response against stretching. Hereby the typical stress-strain profiles are reproduced by implementing the newly discovered and verified "$\\beta$-sheet splitting" mechanism, which primarily varies the secondary structure of protein macromolecules; our modeling and simulation results show good accordance with the experimental measurements. Hence, it can be concluded that the post-yielding mechanical behaviors of both kinds of silks are resulted from the splitting of crystallines while the high extensibility of spider dragline is attributed to the tiny $\\beta$-sheets solely existed in spider silk fibrils. This research reveals for the first time the structural factors leading to the significant difference between spider and silkworm silks in mechanical response to the stretching force. Addition...

  8. Black and brown widow spider bites in South Africa

    African Journals Online (AJOL)

    muscle pain and craInps, abdoIninal Inuscle rigid- ity, profuse .... incolour with a smooth silky surface10 (Fig. 3). .... mitters, acetylcholine and noradrenaline, accounts for the entire clinical .... action are involved, both widow spider and scorpion.

  9. Beyond PICO: the SPIDER tool for qualitative evidence synthesis.

    Science.gov (United States)

    Cooke, Alison; Smith, Debbie; Booth, Andrew

    2012-10-01

    Standardized systematic search strategies facilitate rigor in research. Current search tools focus on retrieval of quantitative research. In this article we address issues relating to using existing search strategy tools, most typically the PICO (Population, Intervention, Comparison, Outcome) formulation for defining key elements of a review question, when searching for qualitative and mixed methods research studies. An alternative search strategy tool for qualitative/mixed methods research is outlined: SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research type). We used both the SPIDER and PICO search strategy tools with a qualitative research question. We have used the SPIDER tool to advance thinking beyond PICO in its suitable application to qualitative and mixed methods research. However, we have highlighted once more the need for improved indexing of qualitative articles in databases. To constitute a viable alternative to PICO, SPIDER needs to be refined and tested on a wider range of topics.

  10. Water-driven actuation of Ornithoctonus huwena spider silk fibers

    Science.gov (United States)

    Lin, Shuyuan; Zhu, Jia; Li, Xinming; Guo, Yang; Fang, Yaopeng; Cheng, Huanyu; Zhu, Hongwei

    2017-01-01

    Spider silk possesses remarkable mechanical properties and can lift weight effectively. Certain kinds of spider silk have unique response to liquid, especially water, because of their hydrophilic proteins, β-sheet characters, and surface structure. The Ornithoctonus huwena (O. huwena) spider is a unique species because it can be bred artificially and it spins silk whose diameter is in nanometer scale. In this work, we report the "shrink-stretch" behavior of the O. huwena spider silk fibers and show how they can be actuated by water to lift weight over long distance, at a fast speed, and with high efficiency. We further rationalize this behavior by analyzing the mechanical energy of the system. The lifting process is energy-efficient and environmentally friendly, allowing applications in actuators, biomimetic muscles, or hoisting devices.

  11. 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.

  12. Unravelling the biodiversity of nanoscale signatures of spider silk fibres

    Science.gov (United States)

    Silva, Luciano P.; Rech, Elibio L.

    2013-12-01

    Living organisms are masters at designing outstanding self-assembled nanostructures through a hierarchical organization of modular proteins. Protein-based biopolymers improved and selected by the driving forces of molecular evolution are among the most impressive archetypes of nanomaterials. One of these biomacromolecules is the myriad of compound fibroins of spider silks, which combine surprisingly high tensile strength with great elasticity. However, no consensus on the nano-organization of spider silk fibres has been reached. Here we explore the biodiversity of spider silk fibres, focusing on nanoscale characterization with high-resolution atomic force microscopy. Our results reveal an evolution of the nanoroughness, nanostiffness, nanoviscoelastic, nanotribological and nanoelectric organization of microfibres, even when they share similar sizes and shapes. These features are related to unique aspects of their molecular structures. The results show that combined nanoscale analyses of spider silks may enable the screening of appropriate motifs for bioengineering synthetic fibres from recombinant proteins.

  13. 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).

  14. 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,

  15. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    NARCIS (Netherlands)

    Yang, Liang; Hedhammar, My; Blom, Tobias; Leifer, Klaus; Johansson, Jan; Habibovic, Pamela; Blitterswijk, van Clemens A.

    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,

  16. Bromeliad-living spiders improve host plant nutrition and growth.

    Science.gov (United States)

    Romero, Gustavo Q; Mazzafera, Paulo; Vasconcellos-Neto, Joao; Trivelin, Paulo C O

    2006-04-01

    Although bromeliads are believed to obtain nutrients from debris deposited by animals in their rosettes, there is little evidence to support this assumption. Using stable isotope methods, we found that the Neotropical jumping spider Psecas chapoda (Salticidae), which lives strictly associated with the terrestrial bromeliad Bromelia balansae, contributed 18% of the total nitrogen of its host plant in a greenhouse experiment. In a one-year field experiment, plants with spiders produced leaves 15% longer than plants from which the spiders were excluded. This is the first study to show nutrient provisioning in a spider-plant system. Because several animal species live strictly associated with bromeliad rosettes, this type of facultative mutualism involving the Bromeliaceae may be more common than previously thought.

  17. Spiders of the Great Dismal Swamp: Lake Drummond 1977

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines the results of a study of spiders that was conducted along the shores of Lake Drummond, in the Great Dismal Swamp. The purpose of the study was...

  18. The Adventures of the Diving-Bell Spider

    Science.gov (United States)

    Thevenin, Raphaele; Dupeux, Guillaume; Piroird, Keyvan; Clanet, Christophe; Quere, David; Interfaces; Co. Team

    2012-11-01

    The Argyroneta Aquatica is a unique spider that has every features of a usual terrestrial spider, but constantly lives under water. To however still be able to breath oxygen, it builds an underwater bell of air (hence its other name ``the diving-bell spider''): using its superhydrophobic abdomen, it pulls an air bubble at the surface by leaving the latter very rapidly. It then enters the bell formed under aquatic plants or under its under-water web, and leaves it more slowly so as to entrain the least air possible. We study these dynamics that take place at the air/water interfaces. We reduce the spider to two beads, one for the hydrophobic abdomen, one for the hydrophilic head, and measure and model the air entrainment according to the size and surface properties of the abdomen and to the velocity of motion.

  19. Duplication and concerted evolution of MiSp-encoding genes underlie the material properties of minor ampullate silks of cobweb weaving spiders.

    Science.gov (United States)

    Vienneau-Hathaway, Jannelle M; Brassfield, Elizabeth R; Lane, Amanda Kelly; Collin, Matthew A; Correa-Garhwal, Sandra M; Clarke, Thomas H; Schwager, Evelyn E; Garb, Jessica E; Hayashi, Cheryl Y; Ayoub, Nadia A

    2017-03-14

    Orb-web weaving spiders and their relatives use multiple types of task-specific silks. The majority of spider silk studies have focused on the ultra-tough dragline silk synthesized in major ampullate glands, but other silk types have impressive material properties. For instance, minor ampullate silks of orb-web weaving spiders are as tough as draglines, due to their higher extensibility despite lower strength. Differences in material properties between silk types result from differences in their component proteins, particularly members of the spidroin (spider fibroin) gene family. However, the extent to which variation in material properties within a single silk type can be explained by variation in spidroin sequences is unknown. Here, we compare the minor ampullate spidroins (MiSp) of orb-weavers and cobweb weavers. Orb-web weavers use minor ampullate silk to form the auxiliary spiral of the orb-web while cobweb weavers use it to wrap prey, suggesting that selection pressures on minor ampullate spidroins (MiSp) may differ between the two groups. We report complete or nearly complete MiSp sequences from five cobweb weaving spider species and measure material properties of minor ampullate silks in a subset of these species. We also compare MiSp sequences and silk properties of our cobweb weavers to published data for orb-web weavers. We demonstrate that all our cobweb weavers possess multiple MiSp loci and that one locus is more highly expressed in at least two species. We also find that the proportion of β-spiral-forming amino acid motifs in MiSp positively correlates with minor ampullate silk extensibility across orb-web and cobweb weavers. MiSp sequences vary dramatically within and among spider species, and have likely been subject to multiple rounds of gene duplication and concerted evolution, which have contributed to the diverse material properties of minor ampullate silks. Our sequences also provide templates for recombinant silk proteins with tailored

  20. Rapid Characterization of Spider Silk Genes via Exon Capture

    Science.gov (United States)

    2015-03-28

    eco - friendly than manmade fibers such as nylon and Kevlar, which are industrially manufactured using harsh chemicals and solvents. These...is persistent demand for the mass production of silks, which requires knowledge of the underlying silk gene sequences. Spidroins (spider fibroins...persistent demand for the mass production of silks, which requires knowledge of the underlying silk gene sequences. Spidroins (spider fibroins), the most

  1. Endosymbiont dominated bacterial communities in a dwarf spider.

    Directory of Open Access Journals (Sweden)

    Bram Vanthournout

    Full Text Available The microbial community of spiders is little known, with previous studies focussing primarily on the medical importance of spiders as vectors of pathogenic bacteria and on the screening of known cytoplasmic endosymbiont bacteria. These screening studies have been performed by means of specific primers that only amplify a selective set of endosymbionts, hampering the detection of unreported species in spiders. In order to have a more complete overview of the bacterial species that can be present in spiders, we applied a combination of a cloning assay, DGGE profiling and high-throughput sequencing on multiple individuals of the dwarf spider Oedothorax gibbosus. This revealed a co-infection of at least three known (Wolbachia, Rickettsia and Cardinium and the detection of a previously unreported endosymbiont bacterium (Rhabdochlamydia in spiders. 16S rRNA gene sequences of Rhabdochlamydia matched closely with those of Candidatus R. porcellionis, which is currently only reported as a pathogen from a woodlouse and with Candidatus R. crassificans reported from a cockroach. Remarkably, this bacterium appears to present in very high proportions in one of the two populations only, with all investigated females being infected. We also recovered Acinetobacter in high abundance in one individual. In total, more than 99% of approximately 4.5M high-throughput sequencing reads were restricted to these five bacterial species. In contrast to previously reported screening studies of terrestrial arthropods, our results suggest that the bacterial communities in this spider species are dominated by, or even restricted to endosymbiont bacteria. Given the high prevalence of endosymbiont species in spiders, this bacterial community pattern could be widespread in the Araneae order.

  2. Acute generalized exanthematous pustulosis associated with spider bite*

    OpenAIRE

    Milman, Laura de Mattos; Müller,Giana Paula; de Souza, Paulo Ricardo Martins; Grill, Aline Barcellos; Rhoden, Deise Louise Bohn; Mello-da-Silva, Carlos Augusto; Vettorato,Gerson

    2016-01-01

    Abstract: Acute generalized exanthematous pustulosis (AGEP) is an acute febrile rash, usually induced by drugs, which recently has been linked to spider bite. We report a case of a male patient, 48 years old, with an erythematous rash accompanied by fever and small non-follicular pustules. He reported previous pain in the buttock with the onset of a necrotic plaque. The lesion was compatible with spider bite of the genus Loxosceles. According to the EuroSCAR group instrument, the patient scor...

  3. Mechanics and Morphology of Silk Drawn from Anesthetized Spiders

    Science.gov (United States)

    Madsen, B.; Vollrath, F.

    CO2 and N2 anesthetized Nephila spiders produced dragline silk with mechanical properties that differed from control silk as a function of time under anesthesia. Silk from CO2 spiders had a significantly lower breaking strain and breaking energy, significantly higher initial modulus, and marginally lower breaking stress. At the onset of anesthesia the silk diameter became highly variable. During deep anesthesia silk either became thinner or retained cross-section but fibrillated.

  4. Benefits of cooperation with genetic kin in a subsocial spider

    DEFF Research Database (Denmark)

    Schneider, J.M.; Bilde, T.

    2008-01-01

    used a cross-fostering design to control for genetic relatedness and group membership. Our study animal was the periodic social spider Stegodyphus lineatus, a transitional species that belongs to a genus containing both permanent social and periodic social species. In S. lineatus, the young cooperate....... Hence, in communally feeding spiders, nepotism favors group retention and reduces the conflict between selfish interests and the interests of the group....

  5. SPIDER Progress Towards High Resolution Correlated Fission Product Data

    Science.gov (United States)

    Shields, Dan; Meierbachtol, Krista; Tovesson, Fredrik; Arnold, Charles; Blackeley, Rick; Bredeweg, Todd; Devlin, Matt; Hecht, Adam; Jandel, Marian; Jorgenson, Justin; Nelson, Ron; White, Morgan; Spider Team

    2014-09-01

    The SPIDER detector (SPectrometer for Ion DEtermination in fission Research) is under development with the goal of obtaining high-resolution, high-efficiency, correlated fission product data needed for many applications including the modeling of next generation nuclear reactors, stockpile stewardship, and the fundamental understanding of the fission process. SPIDER simultaneously measures velocity and energy of both fission products to calculate fission product yields (FPYs), neutron multiplicity (ν), and total kinetic energy (TKE). A detailed description of the prototype SPIDER detector components will be presented. Characterization measurements with alpha and spontaneous fission sources will also be discussed. LA-UR-14-24875. The SPIDER detector (SPectrometer for Ion DEtermination in fission Research) is under development with the goal of obtaining high-resolution, high-efficiency, correlated fission product data needed for many applications including the modeling of next generation nuclear reactors, stockpile stewardship, and the fundamental understanding of the fission process. SPIDER simultaneously measures velocity and energy of both fission products to calculate fission product yields (FPYs), neutron multiplicity (ν), and total kinetic energy (TKE). A detailed description of the prototype SPIDER detector components will be presented. Characterization measurements with alpha and spontaneous fission sources will also be discussed. LA-UR-14-24875. This work is in part supported by LANL Laboratory Directed Research and Development Projects 20110037DR and 20120077DR.

  6. Biodiversity baseline of the French Guiana spider fauna.

    Science.gov (United States)

    Vedel, Vincent; Rheims, Christina; Murienne, Jérôme; Brescovit, Antonio Domingos

    2013-01-01

    The need for an updated list of spiders found in French Guiana rose recently due to many upcoming studies planned. In this paper, we list spiders from French Guiana from existing literature (with corrected nomenclature when necessary) and from 2142 spiders sampled in 12 sites for this baseline study. Three hundred and sixty four validated species names of spider were found in the literature and previous authors' works. Additional sampling, conducted for this study added another 89 identified species and 62 other species with only a genus name for now. The total species of spiders sampled in French Guiana is currently 515. Many other Morphospecies were found but not described as species yet. An accumulation curve was drawn with seven of the sampling sites and shows no plateau yet. Therefore, the number of species inhabiting French Guiana cannot yet be determined. As the very large number of singletons found in the collected materials suggests, the accumulation curve indicates nevertheless that more sampling is necessary to discover the many unknown spider species living in French Guiana, with a focus on specific periods (dry season and wet season) and on specific and poorly studied habitats such as canopy, inselberg and cambrouze (local bamboo monospecific forest).

  7. 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

  8. Molecular Fundaments of Mechanical Properties of Spider Silk

    Institute of Scientific and Technical Information of China (English)

    潘志娟; 刘敏; 李春萍; 李栋高; 盛家镛

    2003-01-01

    Dragline,framework and cocoon silk fibers of Araneus Ventricosus were used for this study.To investigate the microstructure mechanisms of stress-strain behavior of spider silk,firstly,amino acid compositions were analyzed and molecular conformations and crystallinity were measured with Raman spectra and X-ray diffraction respectively.The results showed that there were more amino acids with large side groups and polar ones in spider silk than those of Bombyx silk,and the amino acid distribution varied with different spider silk.The molecular structures were mainly α-helix and β-sheet,and random coil and β-turn existed as well.The proportions and arrangement of these conformations of dragline silk were different from framework and cocoon silk fibers.Microstructure was one of important factors of excellent mechanical properties of spider silk.Crystallinity of spider silk was very low,which implied that the roles of crystal on spider silk were not as great as other protein fibers.

  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.

  10. A clinical and epidemiological study on spider bites in Turkey

    Institute of Scientific and Technical Information of China (English)

    Yildirim Cesaretli; Ozcan Ozkan

    2011-01-01

    Objective:To classify and characterize spider bites among inquiries to the National Poison Information Center (NPIC) between1995 and2004, in terms of the epidemiology and clinical symptomatology.Methods: Clinical and epidemiological data were obtained from theNPIC’s patient records. The following information was recorded for each spider bite: demographics, circumstances of the bite, and local and systemic effects.Results: A total of82 cases were reported. The accidents were mostly seen during August. The gender distribution was59.76%male, 37.20% female, and2.44% unknown and the20-29 age group presented more spider bites. Most of the cases were in the Central Anatolia, Marmara, Mediterranean, and Black Sea regions. Local symptoms were observed in60.87% of the cases, including local pain, edema, redness, itching, debris, burning, and numbness. Systemic symptoms were observed such as nausea, vomiting, abdominal pain, lethargy, anxiety, weakness, somnolence, dyspnea, hypertension, hypotension, and hyperthermia.Conclusions: In conclusion, these findings emphasize the presence of medically important spider species in Turkey. All patients and especially pediatric patients should be admitted to the hospital. Identification of spider species may be considered a useful clinical and epidemiological tool in determining the incidence and risk of spider bites.

  11. Relatedness facilitates cooperation in the subsocial spider, Stegodyphus tentoriicola

    Directory of Open Access Journals (Sweden)

    Bilde Trine

    2009-10-01

    Full Text Available Abstract Background Cooperative hunting and foraging in spiders is rare and prone to cheating such that the actions of selfish individuals negatively affect the whole group. The resulting social dilemma may be mitigated by kin selection since related individuals lose indirect fitness benefits by acting selfishly. Indeed, cooperation with genetic kin reduces the disadvantages of within-group competition in the subsocial spider Stegodyphus lineatus, supporting the hypothesis that high relatedness is an important pre-adaptation in the transition to sociality in spiders. In this study we examined the consequences of group size and relatedness on cooperative feeding in the subsocial spider S. tentoriicola, a species suggested to be at the transition to permanent sociality. Results We formed groups of 3 and 6 spiders that were either siblings or non-siblings. We found that increasing group size negatively affected feeding efficiency but that these negative effects were reduced in sib-groups. Sib groups were more likely to feed cooperatively and all group members grew more homogenously than groups of unrelated spiders. The measured differences did not translate into differential growth or mortality during the experimental period of 8 weeks. Conclusion The combination of our results with those from previous studies indicates that the conflict between individual interests and group interests may be reduced by nepotism and that the latter promote the maintenance of the social community.

  12. Place avoidance learning and memory in a jumping spider.

    Science.gov (United States)

    Peckmezian, Tina; Taylor, Phillip W

    2017-03-01

    Using a conditioned passive place avoidance paradigm, we investigated the relative importance of three experimental parameters on learning and memory in a salticid, Servaea incana. Spiders encountered an aversive electric shock stimulus paired with one side of a two-sided arena. Our three parameters were the ecological relevance of the visual stimulus, the time interval between trials and the time interval before test. We paired electric shock with either a black or white visual stimulus, as prior studies in our laboratory have demonstrated that S. incana prefer dark 'safe' regions to light ones. We additionally evaluated the influence of two temporal features (time interval between trials and time interval before test) on learning and memory. Spiders exposed to the shock stimulus learned to associate shock with the visual background cue, but the extent to which they did so was dependent on which visual stimulus was present and the time interval between trials. Spiders trained with a long interval between trials (24 h) maintained performance throughout training, whereas spiders trained with a short interval (10 min) maintained performance only when the safe side was black. When the safe side was white, performance worsened steadily over time. There was no difference between spiders tested after a short (10 min) or long (24 h) interval before test. These results suggest that the ecological relevance of the stimuli used and the duration of the interval between trials can influence learning and memory in jumping spiders.

  13. Sperm Dynamics in Spiders (Araneae): Ultrastructural Analysis of the Sperm Activation Process in the Garden Spider Argiope bruennichi (Scopoli, 1772)

    OpenAIRE

    Oliver Vöcking; Gabriele Uhl; Peter Michalik

    2013-01-01

    Storage of sperm inside the female genital tract is an integral phase of reproduction in many animal species. The sperm storage site constitutes the arena for sperm activation, sperm competition and female sperm choice. Consequently, to understand animal mating systems information on the processes that occur from sperm transfer to fertilization is required. Here, we focus on sperm activation in spiders. Male spiders produce sperm whose cell components are coiled within the sperm cell and that...

  14. Spider crabs of the Western Atlantic with special reference to fossil and some modern Mithracidae

    Directory of Open Access Journals (Sweden)

    Adiël A. Klompmaker

    2015-10-01

    Full Text Available Spider crabs (Majoidea are well-known from modern oceans and are also common in the western part of the Atlantic Ocean. When spider crabs appeared in the Western Atlantic in deep time, and when they became diverse, hinges on their fossil record. By reviewing their fossil record, we show that (1 spider crabs first appeared in the Western Atlantic in the Late Cretaceous, (2 they became common since the Miocene, and (3 most species and genera are found in the Caribbean region from the Miocene onwards. Furthermore, taxonomic work on some modern and fossil Mithracidae, a family that might have originated in the Western Atlantic, was conducted. Specifically, Maguimithrax gen. nov. is erected to accommodate the extant species Damithrax spinosissimus, while Damithrax cf. pleuracanthus is recognized for the first time from the fossil record (late Pliocene–early Pleistocene, Florida, USA. Furthermore, two new species are described from the lower Miocene coral-associated limestones of Jamaica (Mithrax arawakum sp. nov. and Nemausa windsorae sp. nov.. Spurred by a recent revision of the subfamily, two known species from the same deposits are refigured and transferred to new genera: Mithrax donovani to Nemausa, and Mithrax unguis to Damithrax. The diverse assemblage of decapods from these coral-associated limestones underlines the importance of reefs for the abundance and diversity of decapods in deep time. Finally, we quantitatively show that these crabs possess allometric growth in that length/width ratios drop as specimens grow, a factor that is not always taken into account while describing and comparing among taxa.

  15. Coevolution of female and male genital components to avoid genital size mismatches in sexually dimorphic spiders.

    Science.gov (United States)

    Lupše, Nik; Cheng, Ren-Chung; Kuntner, Matjaž

    2016-08-17

    In most animal groups, it is unclear how body size variation relates to genital size differences between the sexes. While most morphological features tend to scale with total somatic size, this does not necessarily hold for genitalia because divergent evolution in somatic size between the sexes would cause genital size mismatches. Theory predicts that the interplay of female-biased sexual size dimorphism (SSD) and sexual genital size dimorphism (SGD) should adhere to the 'positive genital divergence', the 'constant genital divergence', or the 'negative genital divergence' model, but these models remain largely untested. We test their validity in the spider family Nephilidae known for the highest degrees of SSD among terrestrial animals. Through comparative analyses of sex-specific somatic and genital sizes, we first demonstrate that 99 of the 351 pairs of traits are phylogenetically correlated. Through factor analyses we then group these traits for MCMCglmm analyses that test broader correlation patterns, and these reveal significant correlations in 10 out of the 36 pairwise comparisons. Both types of analyses agree that female somatic and internal genital sizes evolve independently. While sizes of non-intromittent male genital parts coevolve with male body size, the size of the intromittent male genital parts is independent of the male somatic size. Instead, male intromittent genital size coevolves with female (external and, in part, internal) genital size. All analyses also agree that SGD and SSD evolve independently. Internal dimensions of female genitalia evolve independently of female body size in nephilid spiders, and similarly, male intromittent genital size evolves independently of the male body size. The size of the male intromittent organ (the embolus) and the sizes of female internal and external genital components thus seem to respond to selection against genital size mismatches. In accord with these interpretations, we reject the validity of the

  16. Exogenous attention to fear: Differential behavioral and neural responses to snakes and spiders.

    Science.gov (United States)

    Soares, Sandra C; Kessel, Dominique; Hernández-Lorca, María; García-Rubio, María J; Rodrigues, Paulo; Gomes, Nuno; Carretié, Luis

    2017-03-06

    Research has consistently shown that threat stimuli automatically attract attention in order to activate the defensive response systems. Recent findings have provided evidence that snakes tuned the visual system of evolving primates for their astute detection, particularly under challenging perceptual conditions. The goal of the present study was to measure behavioral and electrophysiological indices of exogenous attention to snakes, compared with spiders - matched for rated fear levels but for which sources of natural selection are less well grounded, and to innocuous animals (birds), which were presented as distracters, while participants were engaged in a letter discrimination task. Duration of stimuli, consisting in a letter string and a concurrent distracter, was either presented for 180 or 360ms to explore if the stimulus duration was a modulating effect of snakes in capturing attention. Results showed a specific early (P1) exogenous attention-related brain potential with maximal amplitude to snakes in both durations, which was followed by an enhanced late attention-related potential (LPP) showing enhanced amplitudes to spiders, particularly under the longer exposure durations. These results suggest that exogenous attention to different classes of threat stimuli follows a gradual process, with the most evolutionary-driven stimulus, i.e., snakes, being more efficient at attracting early exogenous attention, thus more dependent on bottom-up processes.

  17. Spider Web DNA: A New Spin on Noninvasive Genetics of Predator and Prey.

    Directory of Open Access Journals (Sweden)

    Charles C Y Xu

    Full Text Available Noninvasive genetic sampling enables biomonitoring without the need to directly observe or disturb target organisms. This paper describes a novel and promising source of noninvasive spider and insect DNA from spider webs. Using black widow spiders (Latrodectus spp. fed with house crickets (Acheta domesticus, we successfully extracted, amplified, and sequenced mitochondrial DNA from spider web samples that identified both spider and prey to species. Detectability of spider DNA did not differ between assays with amplicon sizes from 135 to 497 base pairs. Spider and prey DNA remained detectable at least 88 days after living organisms were no longer present on the web. Spider web DNA as a proof-of-concept may open doors to other practical applications in conservation research, pest management, biogeography studies, and biodiversity assessments.

  18. Spider Web DNA: A New Spin on Noninvasive Genetics of Predator and Prey.

    Science.gov (United States)

    Xu, Charles C Y; Yen, Ivy J; Bowman, Dean; Turner, Cameron R

    2015-01-01

    Noninvasive genetic sampling enables biomonitoring without the need to directly observe or disturb target organisms. This paper describes a novel and promising source of noninvasive spider and insect DNA from spider webs. Using black widow spiders (Latrodectus spp.) fed with house crickets (Acheta domesticus), we successfully extracted, amplified, and sequenced mitochondrial DNA from spider web samples that identified both spider and prey to species. Detectability of spider DNA did not differ between assays with amplicon sizes from 135 to 497 base pairs. Spider and prey DNA remained detectable at least 88 days after living organisms were no longer present on the web. Spider web DNA as a proof-of-concept may open doors to other practical applications in conservation research, pest management, biogeography studies, and biodiversity assessments.

  19. Wolbachia screening in spiders and assessment of horizontal transmission between predator and prey.

    Science.gov (United States)

    Yun, Y; Peng, Y; Liu, F X; Lei, C

    2011-01-01

    Recent studies have revealed that the prevalence of Wolbachia in arthropods is attributable not only to its vertical transmission, but also to its horizontal transfer. In order to assess the horizontal transmission of Wolbachia between predator and prey, arthropods belonging to 11 spider families and six insect families were collected in the same field of rice. The distribution of Wolbachia in these arthropods was detected by diagnostic PCR amplification of the wsp (Wolbachia outer surface protein gene) and 16S rDNA genes. Nurscia albofasciata Strand (Araneae: Titanoecidae), Propylea japonica Thunberg (Coleoptera: Coccinellidae), Paederus fuscipes Curtis (Coleoptera: Staphylinidae), and Nilaparvata lugens Stal (Homoptera: Delphacidae) were infected with Wolbachia. This is the first report of infection of N. albofasciata and P. fuscipes by Wolbachia. No direct evidence indicated the existence of horizontal transmission of Wolbachia between predator and prey.

  20. Four new Mouse Spider species (Araneae, Mygalomorphae, Actinopodidae, Missulena from Western Australia

    Directory of Open Access Journals (Sweden)

    Laura Miglio

    2014-05-01

    Full Text Available Four new species of the Mouse Spider genus Missulena Walckenaer, 1805 (family Actinopodidae are described from Western Australia based on morphological features of adult males. Missulena leniae sp. n. (from the Carnarvon and Yalgoo biogeographic regions, Missulena mainae sp. n. (Carnarvon, Missulena melissae sp. n. (Pilbara and Missulena pinguipes sp. n. (Mallee represent a broad spectrum of morphological diversity found in this genus and differ from other congeners by details of the male copulatory bulb, colour patterns, eye sizes, leg morphology and leg spination. Two of the species, M. pinguipes sp. n. and M. mainae sp. n., are characterised by swollen metatarsi of the fourth legs in males, a feature not previously recorded in the family. A key to males of all named Missulena species from Australia is presented and allows their identification based on external morphology.

  1. Brain dynamics in spider-phobic individuals exposed to phobia-relevant and other emotional stimuli

    OpenAIRE

    Michalowski, Jaroslaw; Melzig, Christiane; Weike, Almut I.; Stockburger, Jessica; Schupp, Harald Thomas; Hamm, Alfons

    2009-01-01

    Dense sensor event-related brain potentials were measured in participants with spider phobia and nonfearful controls during viewing of phobia-relevant spider and standard emotional (pleasant, unpleasant, neutral) pictures. Irrespective of the picture content, spider phobia participants responded with larger P1 amplitudes than controls, suggesting increased vigilance in this group. Furthermore, spider phobia participants showed a significantly enlarged early posterior negativity (EPN) and late...

  2. 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…

  3. 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…

  4. A revised and dated phylogeny of cobweb spiders (Araneae, Araneoidea, Theridiidae): A predatory Cretaceous lineage diversifying in the era of the ants (Hymenoptera, Formicidae).

    Science.gov (United States)

    Liu, Jie; May-Collado, Laura J; Pekár, Stano; Agnarsson, Ingi

    2016-01-01

    Cobweb spiders (Theridiidae) are highly diverse from the perspective of species richness, morphological diversity, variety of web architecture, and behavioral repertoires. The family includes over 50% of social spiders, a behavioral rarity among the order, and members of the family are furthermore the subject of research on venom, silk biomechanics, kleptoparasitism and web building, among other traits. Theridiidae is one of the most abundant groups of spiders, and thus key insect predators in many different ecosystems and is among relatively few spider families that show high degree of myrmecophagy. Modern comparative studies on all these fronts are best buttressed on a phylogenetic foundation. Our goal here is to offer a revised, dated, phylogenetic hypothesis for the family by summarizing previously published data from multiple molecular and morphological studies through data-mining, and adding novel data from several genera. We also test the hypothesis that the origin and diversification of cobweb spiders coincides with that of ants on which many species specialize as prey. The new phylogeny is largely congruent with prior studies and current taxonomy and should provide a useful tool for theridiid classification and for comparative analyses. Nevertheless, we also highlight the limitations of currently available data-the state of the art in Theridiidae phylogenetics-offering weak support for most of the deeper nodes in the phylogeny. Thus the need is clear for modern phylogenomic approaches to obtain a more solid understanding, especially of relationships among subfamilies. We recover the monophyly of currently recognized theridiid subfamilies with the exception of some enigmatic 'pholcommatines' (Styposis, Phoroncidia) and putative 'hadrotarsines' (Audifia, Tekellina) whose placement is uncertain in our analyses. Theridiidae dates back some 100 mya to the Cretaceous, a period of diversification in flowering plants and many groups of insects, including ants. The

  5. Isolation and characterization of a protein neurotoxin from the venom glands of the funnel-web spider (Atrax robustus).

    Science.gov (United States)

    Gregson, R P; Spence, I

    1983-01-01

    1. Ground venom glands from male and female funnel-web spiders (Atrax robustus) were extracted with acetic acid (0.35 M). 2. A protein constituent of these extracts, atraxin, which caused muscle fasciculation when applied to the phrenic nerve-hemidiaphragm of the mouse in vitro, was isolated by the sequential application of ultrafiltration, gel permeation and ion exchange chromatography. 3. When subjected to isoelectricfocusing, amino acid analysis, ultracentrifugation, ultraviolet and 1H nuclear magnetic resonance spectroscopy, it was shown that atraxin had an approximate molecular weight of 9800, an isoelectric point of greater than 9 and that it contained 76 amino acid residues.

  6. Isolation of delta-missulenatoxin-Mb1a, the major vertebrate-active spider delta-toxin from the venom of Missulena bradleyi (Actinopodidae).

    Science.gov (United States)

    Gunning, Simon J; Chong, Youmie; Khalife, Ali A; Hains, Peter G; Broady, Kevin W; Nicholson, Graham M

    2003-11-06

    The present study describes the isolation and pharmacological characterisation of the neurotoxin delta-missulenatoxin-Mb1a (delta-MSTX-Mb1a) from the venom of the male Australian eastern mouse spider, Missulena bradleyi. This toxin was isolated using reverse-phase high-performance liquid chromatography and was subsequently shown to cause an increase in resting tension, muscle fasciculation and a decrease in indirect twitch tension in a chick biventer cervicis nerve-muscle bioassay. Interestingly, these effects were neutralised by antivenom raised against the venom of the Sydney funnel-web spider Atrax robustus. Subsequent whole-cell patch-clamp electrophysiology on rat dorsal root ganglion neurones revealed that delta-MSTX-Mb1a caused a reduction in peak tetrodotoxin (TTX)-sensitive sodium current, a slowing of sodium current inactivation and a hyperpolarising shift in the voltage at half-maximal activation. In addition, delta-MSTX-Mb1a failed to affect TTX-resistant sodium currents. Subsequent Edman degradation revealed a 42-residue peptide with unusual N- and C-terminal cysteines and a cysteine triplet (Cys(14-16)). This toxin was highly homologous to a family of delta-atracotoxins (delta-ACTX) from Australian funnel-web spiders including conservation of all eight cysteine residues. In addition to actions on sodium channel gating and kinetics to delta-ACTX, delta-MSTX-Mb1a caused significant insect toxicity at doses up to 2000 pmol/g. Delta-MSTX-Mb1a therefore provides evidence of a highly conserved spider delta-toxin from a phylogenetically distinct spider family that has not undergone significant modification.

  7. Arachnids of medical importance in Brazil: main active compounds present in scorpion and spider venoms and tick saliva.

    Science.gov (United States)

    Cordeiro, Francielle A; Amorim, Fernanda G; Anjolette, Fernando A P; Arantes, Eliane C

    2015-01-01

    Arachnida is the largest class among the arthropods, constituting over 60,000 described species (spiders, mites, ticks, scorpions, palpigrades, pseudoscorpions, solpugids and harvestmen). Many accidents are caused by arachnids, especially spiders and scorpions, while some diseases can be transmitted by mites and ticks. These animals are widely dispersed in urban centers due to the large availability of shelter and food, increasing the incidence of accidents. Several protein and non-protein compounds present in the venom and saliva of these animals are responsible for symptoms observed in envenoming, exhibiting neurotoxic, dermonecrotic and hemorrhagic activities. The phylogenomic analysis from the complementary DNA of single-copy nuclear protein-coding genes shows that these animals share some common protein families known as neurotoxins, defensins, hyaluronidase, antimicrobial peptides, phospholipases and proteinases. This indicates that the venoms from these animals may present components with functional and structural similarities. Therefore, we described in this review the main components present in spider and scorpion venom as well as in tick saliva, since they have similar components. These three arachnids are responsible for many accidents of medical relevance in Brazil. Additionally, this study shows potential biotechnological applications of some components with important biological activities, which may motivate the conducting of further research studies on their action mechanisms.

  8. Male-directed infanticide in spider monkeys (Ateles spp.).

    Science.gov (United States)

    Alvarez, Sara; Di Fiore, Anthony; Champion, Jane; Pavelka, Mary Susan; Páez, Johanna; Link, Andrés

    2015-04-01

    Infanticide is considered a conspicuous expression of sexual conflict amongst mammals, including at least 35 primate species. Here we describe two suspected and one attempted case of intragroup infanticide in spider monkeys that augment five prior cases of observed or suspected infanticide in this genus. Contrary to the typical pattern of infanticide seen in most primate societies, where infants are killed by conspecifics independent of their sex, all eight cases of observed or suspected infanticide in spider monkeys have been directed toward male infants within their first weeks of life. Moreover, although data are still scant, infanticides seem to be perpetrated exclusively by adult males against infants from their own social groups and are not associated with male takeovers or a sudden rise in male dominance rank. Although the slow reproductive cycles of spider monkeys might favor the presence of infanticide because of the potential to shorten females' interbirth intervals, infanticide is nonetheless uncommon among spider monkeys, and patterns of male-directed infanticide are not yet understood. We suggest that given the potentially close genetic relationships among adult males within spider monkey groups, and the need for males to cooperate with one another in territorial interactions with other groups of related males, infanticide may be expected to occur primarily where the level of intragroup competition among males outweighs that of competition between social groups. Finally, we suggest that infanticide in spider monkeys may be more prevalent than previously thought, given that it may be difficult for observers to witness cases of infanticide or suspected infanticide that occur soon after birth in taxa that are characterized by high levels of fission-fusion dynamics. Early, undetected, male-biased infanticide could influence the composition of spider monkey groups and contribute to the female-biased adult sex ratios often reported for this genus.

  9. 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

    2011-05-07

    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.

  10. 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,…

  11. Spider (Arachnida, Araneae) diversity in secondary and old-growth southern Atlantic forests of Paraná state, Brazil.

    Science.gov (United States)

    Raub, Florian; Höfer, Hubert; Scheuermann, Ludger

    2017-07-01

    The data presented here have been collected in the southern part of the Atlantic Forest (Mata Atlântica) in the state of Paraná, Brazil within a bilateral scientific project (SOLOBIOMA). The project aimed to assess the quality of secondary forests of different regeneration stages in comparison with old-growth forests with regard to diversity of soil animals and related functions. The Atlantic Forest is a hotspot of biological diversity with an exceptionally high degree of endemic species, extending over a range of 3,500 km along the coast of Brazil. The anthropogenic pressure in the region is very high with three of the biggest cities of Brazil (São Paulo, Rio de Janeiro, and Curitiba) lying in its extension. An evaluation of the value of secondary forests for biodiversity conservation is becoming more and more important due to the complete disappearance of primary forests. In 2005, we sampled spiders in 12 sites of three successional stages (5-8, 10-15, 35-50 yr old, three replicates of each forest stage) and old-growth forests (> 100 yr untouched, also three replicates). All sites were inside a private nature reserve (Rio Cachoeira Nature Reserve). We repeated the sampling design and procedure in 2007 in a second private reserve (Itaqui Nature Reserve). The two nature reserves are within about 25 km of each other within a well preserved region of the Mata Atlântica, where the matrix of the landscape mosaic is still forest. A widely accepted standard protocol was used in a replicated sampling design to apply statistical analyses to the resulting data set and allow for comparison with other studies in Brazil. Spiders were sorted to family level and counted; the adult spiders further identified to species if possible or classified as morphospecies with the help of several spider specialists. © 2017 by the Ecological Society of America.

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

    Science.gov (United States)

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

    2012-12-01

    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 putative horizontal gene transfers, including a gene that encodes a cyanase or cyanate lyase. In this study we show by recombinant expression that the T. urticae cyanase remained functionally active after horizontal gene transfer and has a high affinity for cyanate. Cyanases were also detected in other plant parasitic spider mites species such as Tetranychus evansi and Panonychus citri, suggesting that an ancient gene transfer occurred before the diversification within the Tetranychidae family. To investigate the potential role of cyanase in the evolution of plant parasitic spider mites, we studied cyanase expression patterns in T. urticae in relation to host plant range and cyanogenesis, a common plant defense mechanism. Spider mites can alter cyanase expression levels after transfer to several new host plants, including the cyanogenic Phaseolus lunatus. However, the role of cyanase is probably not restricted to cyanide response, but likely to the plant nutritional quality as a whole. We finally discuss potential interactions between cyanase activity and pyrimidine and amino acid synthesis.

  13. Evolutionary morphology of the male reproductive system, spermatozoa and seminal fluid of spiders (Araneae, Arachnida)--current knowledge and future directions.

    Science.gov (United States)

    Michalik, Peter; Ramírez, Martín J

    2014-07-01

    The male reproductive system and spermatozoa of spiders are known for their high structural diversity. Spider spermatozoa are flagellate and males transfer them to females in a coiled and encapsulated state using their modified pedipalps. Here, we provide a detailed overview of the present state of knowledge of the primary male reproductive system, sperm morphology and the structural diversity of seminal fluids with a focus on functional and evolutionary implications. Secondly, we conceptualized characters for the male genital system, spermiogenesis and spermatozoa for the first time based on published and new data. In total, we scored 40 characters for 129 species from 56 families representing all main spider clades. We obtained synapomorphies for several taxa including Opisthothelae, Araneomorphae, Dysderoidea, Scytodoidea, Telemidae, Linyphioidea, Mimetidae, Synotaxidae and the Divided Cribellum Clade. Furthermore, we recovered synspermia as a synapomorphy for ecribellate Haplogynae and thus propose Synspermiata as new name for this clade. We hope that these data will not only contribute to future phylogenetic studies but will also stimulate much needed evolutionary studies of reproductive systems in spiders. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Grounded theory.

    Science.gov (United States)

    Harris, Tina

    2015-04-29

    Grounded theory is a popular research approach in health care and the social sciences. This article provides a description of grounded theory methodology and its key components, using examples from published studies to demonstrate practical application. It aims to demystify grounded theory for novice nurse researchers, by explaining what it is, when to use it, why they would want to use it and how to use it. It should enable nurse researchers to decide if grounded theory is an appropriate approach for their research, and to determine the quality of any grounded theory research they read.

  15. Complex female genitalia indicate sperm dumping in armored goblin spiders (Arachnida, Araneae, Oonopidae).

    Science.gov (United States)

    Burger, Matthias

    2010-01-01

    In promiscuous females, sperm ejection from the sperm storage site can be a strong mechanism to influence sperm priority patterns. Sperm dumping is reported from different animals including birds, insects, and humans. In spiders, it has been documented for four species including the oonopid Silhouettella loricatula. Oonopidae are a diverse spider family comprising many species with peculiar female genitalia. Especially in species where studies of mating behavior are difficult, morphological investigations of the genitalia help to understand their function and evolution. In the present study, the genitalia of the oonopids Myrmopopaea sp., Grymeus sp., and Lionneta sp. are investigated by means of histological serial sections and scanning electron microscopy (SEM). The results are compared with previous findings on S. loricatula. In Myrmopopaea sp. and Grymeus sp., the same morphological components are present that are involved in sperm dumping in S. loricatula. Inside the receptaculum, sperm are enclosed in a secretory sac which can be moved to the genital opening and dumped during copulation by muscle contractions. The female genitalia of Lionneta sp. are asymmetric. They show the same characteristics as S. loricatula but all the investigated females were unmated. The results strongly suggest that sperm dumping occurs in Myrmopopaea sp., Grymeus sp., and Lionneta sp. and happens by the same mechanism as in S. loricatula. Sperm dumping might even be common within a clade of oonopids. As in S. loricatula, the sperm transfer forms in the investigated species consist of several spermatozoa. Papillae with unknown function occur on the receptacula of all females.

  16. Hierarchical self-assembly of spider silk-like block copolymers

    Science.gov (United States)

    Krishnaji, Sreevidhya; Huang, Wenwen; Cebe, Peggy; Kaplan, David

    2011-03-01

    Block copolymers provide an attractive venue to study well-defined nano-structures that self-assemble to generate functionalized nano- and mesoporous materials. In the present study, a novel family of spider silk-like block copolymers was designed, bioengineered and characterized to study the impact of sequence chemistry, secondary structure and block length on assembled morphology. Genetic variants of native spider dragline silk (major ampullate spidroin I, Nephila clavipes) were used as polymer building blocks. Characterization by FTIR revealed increased ?-sheet content with increasing hydrophobic A blocks; SEM revealed spheres, rod-like structures, bowl-shaped and giant compound micelles. Langmuir Blodgett monolayers were prepared at the air-water interface at different surface pressures and monolayer films analyzed by AFM revealed oblate to prolate structures. Circular micelles, rod-like, densely packed circular structures were observed for HBA6 at increasing surface pressure. Exploiting hierarchical assembly provide a promising approach to rationale designs of protein block copolymer systems, allowing comparison to traditional synthetic systems.

  17. A golden orb-weaver spider (Araneae: Nephilidae: Nephila) from the Middle Jurassic of China.

    Science.gov (United States)

    Selden, Paul A; Shih, ChungKun; Ren, Dong

    2011-10-23

    Nephila are large, conspicuous weavers of orb webs composed of golden silk, in tropical and subtropical regions. Nephilids have a sparse fossil record, the oldest described hitherto being Cretaraneus vilaltae from the Cretaceous of Spain. Five species from Neogene Dominican amber and one from the Eocene of Florissant, CO, USA, have been referred to the extant genus Nephila. Here, we report the largest known fossil spider, Nephila jurassica sp. nov., from Middle Jurassic (approx. 165 Ma) strata of Daohugou, Inner Mongolia, China. The new species extends the fossil record of the family by approximately 35 Ma and of the genus Nephila by approximately 130 Ma, making it the longest ranging spider genus known. Nephilidae originated somewhere on Pangaea, possibly the North China block, followed by dispersal almost worldwide before the break-up of the supercontinent later in the Mesozoic. The find suggests that the palaeoclimate was warm and humid at this time. This giant fossil orb-weaver provides evidence of predation on medium to large insects, well known from the Daohugou beds, and would have played an important role in the evolution of these insects.

  18. A check list of the spider fauna of the Western Soutpansberg, South Africa (Arachnida: Araneae

    Directory of Open Access Journals (Sweden)

    S.H. Foord

    2002-12-01

    Full Text Available By virtue of its geological history and geographical location the Soutpansberg constitutes a refuge for a high diversity of organisms. The Western Soutpansberg forms part of the Savanna Biome and is presently the area with the highest concentration of Natural Heritage Sites in South Africa. A unique private initiative is under way to improve its national and international conservation status in a bid to conserve the mountain. A checklist of the spider species of the Western Soutpansberg collected over a five-year period is presented. Forty-six families, represented by 109 genera and 127 species have been collected. Of the species collected, 81 (64 % were wandering spiders and 46 (36 % web builders. The Thomisidae have the highest number of species (15 followed by the Araneidae and the Salticidae with 10 species each. Ninety-six genera are represented by a single species. Ninety six percent of the species collected are new records for the area. This survey is the first for the area and forms part of the South African National Survey of Arachnida (SANSA.

  19. A genus-level taxonomic review of primitively segmented spiders (Mesothelae, Liphistiidae

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    Xu Xin

    2015-03-01

    Full Text Available The spider suborder Mesothelae, containing a single extant family Liphistiidae, represents a species-poor and ancient lineage. These are conspicuous spiders that primitively retain a segmented abdomen and appendage-like spinnerets. While their classification history is nearly devoid of phylogenetic hypotheses, we here revise liphistiid genus level taxonomy based on original sampling throughout their Asian range, and on the evidence from a novel molecular phylogeny. By combining morphological and natural history evidence with phylogenetic relationships in the companion paper, we provide strong support for the monophyly of Liphistiidae, and the two subfamilies Liphistiinae and Heptathelinae. While the former only contains Liphistius Schiödte, 1849, a genus distributed in Indonesia (Sumatra, Laos, Malaysia, Myanmar, Thailand, we recognize and diagnose seven heptatheline genera, all but three removed from the synonymy of Heptathela: i Ganthela Xu & Kuntner, gen. n. with the type species G. yundingensis Xu, sp. n. is known from Fujian and Jiangxi, China; ii a rediagnosed Heptathela Kishida, 1923 is confined to the Japanese islands (Kyushu and Okinawa; iii Qiongthela Xu & Kuntner, gen. n. with the type species Q. baishensis Xu, sp. n. is distributed disjunctly in Hainan, China and Vietnam; iv Ryuthela Haupt, 1983 is confined to the Ryukyu archipelago (Japan; v Sinothela Haupt, 2003 inhabits Chinese areas north of Yangtze; vi Songthela Ono, 2000 inhabits southwest China and northern Vietnam; and vii Vinathela Ono, 2000 (Abcathela Ono, 2000, syn. n.; Nanthela Haupt, 2003, syn. n. is known from southeast China and Vietnam.

  20. Spatio-temporal differentiation and sociality in spiders.

    Directory of Open Access Journals (Sweden)

    Jessica Purcell

    Full Text Available Species that differ in their social system, and thus in traits such as group size and dispersal timing, may differ in their use of resources along spatial, temporal, or dietary dimensions. The role of sociality in creating differences in habitat use is best explored by studying closely related species or socially polymorphic species that differ in their social system, but share a common environment. Here we investigate whether five sympatric Anelosimus spider species that range from nearly solitary to highly social differ in their use of space and in their phenology as a function of their social system. By studying these species in Serra do Japi, Brazil, we find that the more social species, which form larger, longer-lived colonies, tend to live inside the forest, where sturdier, longer lasting vegetation is likely to offer better support for their nests. The less social species, which form single-family groups, in contrast, tend to occur on the forest edge where the vegetation is less robust. Within these two microhabitats, species with longer-lived colonies tend to occupy the potentially more stable positions closer to the core of the plants, while those with smaller and shorter-lived colonies build their nests towards the branch tips. The species further separate in their use of common habitat due to differences in the timing of their reproductive season. These patterns of habitat use suggest that the degree of sociality can enable otherwise similar species to differ from one another in ways that may facilitate their co-occurrence in a shared environment, a possibility that deserves further consideration.