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Sample records for black widow spider

  1. Black Widow Spider

    Science.gov (United States)

    ... dling boxes, firewood, lumber, and rocks, etc. The black widow is commonly found in the following places: • Outdoors - woodpiles, rubble piles, under stones, in hol- low stumps, and in rodent burrows, privies, sheds ...

  2. Postharvest fumigation of California table grapes with ozone to control Western black widow spider (Araneae: Theridiidae)

    Science.gov (United States)

    Ozone fumigations were evaluated for postharvest control of Western black widow spider (BWS), Latrodectus hesperus (Chamberlin and Ivie), in fresh table grapes destined for export from California USA. Mature adult female black widow spiders were contained in separate gas-permeable cages within a flo...

  3. Microdissection of black widow spider silk-producing glands.

    Science.gov (United States)

    Jeffery, Felicia; La Mattina, Coby; Tuton-Blasingame, Tiffany; Hsia, Yang; Gnesa, Eric; Zhao, Liang; Franz, Andreas; Vierra, Craig

    2011-01-01

    Modern spiders spin high-performance silk fibers with a broad range of biological functions, including locomotion, prey capture and protection of developing offspring. Spiders accomplish these tasks by spinning several distinct fiber types that have diverse mechanical properties. Such specialization of fiber types has occurred through the evolution of different silk-producing glands, which function as small biofactories. These biofactories manufacture and store large quantities of silk proteins for fiber production. Through a complex series of biochemical events, these silk proteins are converted from a liquid into a solid material upon extrusion. Mechanical studies have demonstrated that spider silks are stronger than high-tensile steel. Analyses to understand the relationship between the structure and function of spider silk threads have revealed that spider silk consists largely of proteins, or fibroins, that have block repeats within their protein sequences. Common molecular signatures that contribute to the incredible tensile strength and extensibility of spider silks are being unraveled through the analyses of translated silk cDNAs. Given the extraordinary material properties of spider silks, research labs across the globe are racing to understand and mimic the spinning process to produce synthetic silk fibers for commercial, military and industrial applications. One of the main challenges to spinning artificial spider silk in the research lab involves a complete understanding of the biochemical processes that occur during extrusion of the fibers from the silk-producing glands. Here we present a method for the isolation of the seven different silk-producing glands from the cobweaving black widow spider, which includes the major and minor ampullate glands [manufactures dragline and scaffolding silk], tubuliform [synthesizes egg case silk], flagelliform [unknown function in cob-weavers], aggregate [makes glue silk], aciniform [synthesizes prey wrapping and egg

  4. Reversible Myocarditis and Pericarditis after Black Widow Spider Bite or Kounis Syndrome?

    OpenAIRE

    Mehmet Yaman; Turkan Mete; Ismail Ozer; Elif Yaman; Osman Beton

    2015-01-01

    Clinical manifestation of black widow spider bite is variable and occasionally leads to death in rural areas. Cases of myocarditis and pericarditis after black widow spider bite are rare and the associated prognostic significance is unknown. Kounis syndrome has been defined as an acute coronary syndrome in the setting of allergic or hypersensitivity and anaphylactic or anaphylactoid insults that manifests as vasospastic angina or acute myocardial infarction or stent thrombosis. Allergic myoca...

  5. Reversible Myocarditis and Pericarditis after Black Widow Spider Bite or Kounis Syndrome?

    Science.gov (United States)

    Yaman, Mehmet; Mete, Turkan; Ozer, Ismail; Yaman, Elif; Beton, Osman

    2015-01-01

    Clinical manifestation of black widow spider bite is variable and occasionally leads to death in rural areas. Cases of myocarditis and pericarditis after black widow spider bite are rare and the associated prognostic significance is unknown. Kounis syndrome has been defined as an acute coronary syndrome in the setting of allergic or hypersensitivity and anaphylactic or anaphylactoid insults that manifests as vasospastic angina or acute myocardial infarction or stent thrombosis. Allergic myocarditis is caused by myocardial inflammation triggered by infectious pathogens, toxic, ischemic, or mechanical injuries, such as drug-related inflammation and other immune reactions. A 15-year-old child was admitted to the emergency department with pulmonary edema after spider bite. ST segment depression on ECG, elevated cardiac enzymes and global left ventricular hypokinesia (with ejection fraction of 22%), and local pericardial effusion findings confirmed the diagnosis of myopericarditis. After heart failure and pulmonary edema oriented medical therapy, clinical status improved. Patient showed a progressive improvement and LV functions returned to normal on the sixth day. Myopericarditis complicating spider bite is rare and sometimes fatal. The mechanism is not clearly known. Alpha-latrotoxin of the black widow spider is mostly convicted in these cases. But allergy or hypersensitivity may play a role in myocardial damage. PMID:26509087

  6. Reversible Myocarditis and Pericarditis after Black Widow Spider Bite or Kounis Syndrome?

    Directory of Open Access Journals (Sweden)

    Mehmet Yaman

    2015-01-01

    Full Text Available Clinical manifestation of black widow spider bite is variable and occasionally leads to death in rural areas. Cases of myocarditis and pericarditis after black widow spider bite are rare and the associated prognostic significance is unknown. Kounis syndrome has been defined as an acute coronary syndrome in the setting of allergic or hypersensitivity and anaphylactic or anaphylactoid insults that manifests as vasospastic angina or acute myocardial infarction or stent thrombosis. Allergic myocarditis is caused by myocardial inflammation triggered by infectious pathogens, toxic, ischemic, or mechanical injuries, such as drug-related inflammation and other immune reactions. A 15-year-old child was admitted to the emergency department with pulmonary edema after spider bite. ST segment depression on ECG, elevated cardiac enzymes and global left ventricular hypokinesia (with ejection fraction of 22%, and local pericardial effusion findings confirmed the diagnosis of myopericarditis. After heart failure and pulmonary edema oriented medical therapy, clinical status improved. Patient showed a progressive improvement and LV functions returned to normal on the sixth day. Myopericarditis complicating spider bite is rare and sometimes fatal. The mechanism is not clearly known. Alpha-latrotoxin of the black widow spider is mostly convicted in these cases. But allergy or hypersensitivity may play a role in myocardial damage.

  7. Isolation and Preliminary Characterization of Proteinaceous Toxins with Insecticidal and Antibacterial Activities from Black Widow Spider (L. tredecimguttatus Eggs

    Directory of Open Access Journals (Sweden)

    Qian Lei

    2015-03-01

    Full Text Available The eggs of black widow spider (L. tredecimguttatus have been demonstrated to be rich in toxic proteinaceous components. The study on such active components is of theoretical and practical importance. In the present work, using a combination of multiple biochemical and biological strategies, we isolated and characterized the proteinaceous components from the aqueous extract of the black widow spider eggs. After gel filtration of the egg extract, the resulting main protein and peptide peaks were further fractionated by ion exchange chromatography and reversed-phase high performance liquid chromatography. Two proteinaceous components, named latroeggtoxin-III and latroeggtoxin-IV, respectively, were purified to homogeneity. Latroeggtoxin-III was demonstrated to have a molecular weight of about 36 kDa. Activity analysis indicated that latroeggtoxin-III exhibited neurotoxicity against cockroaches but had no obvious effect on mice, suggesting that it is an insect-specific toxin. Latroeggtoxin-IV, with a molecular weight of 3.6 kDa, was shown to be a broad-spectrum antibacterial peptide, showing inhibitory activity against all five species of bacteria tested, with the highest activity against Staphylococcus aureus. Finally, the implications of the proteinaceous toxins in egg protection and their potential applications were analyzed and discussed.

  8. From the Black Widow Spider to Human Behavior: Latrophilins, a Relatively Unknown Class of G Protein-Coupled Receptors, Are Implicated in Psychiatric Disorders

    OpenAIRE

    Martinez, Ariel F; Muenke, Maximilian; Arcos-Burgos, Mauricio

    2010-01-01

    The findings of a recent study associate LPHN3, a member of the latrophilin family, with an increased risk of developing attention deficit/hyperactivity disorder (ADHD), the most common psychiatric disorder in childhood and adolescence. Latrophilins comprise a new family of G protein-coupled receptors of unknown native physiological function that mediate the neurotoxic effects of α-latrotoxin, a potent toxin found in black widow spider venom. This receptor–toxin interaction has helped to eluc...

  9. From the black widow spider to human behavior: Latrophilins, a relatively unknown class of G protein-coupled receptors, are implicated in psychiatric disorders.

    Science.gov (United States)

    Martinez, Ariel F; Muenke, Maximilian; Arcos-Burgos, Mauricio

    2011-01-01

    The findings of a recent study associate LPHN3, a member of the latrophilin family, with an increased risk of developing attention deficit/hyperactivity disorder (ADHD), the most common psychiatric disorder in childhood and adolescence. Latrophilins comprise a new family of G protein-coupled receptors of unknown native physiological function that mediate the neurotoxic effects of α-latrotoxin, a potent toxin found in black widow spider venom. This receptor-toxin interaction has helped to elucidate the mechanistic aspects of neurotransmitter and hormone release in vertebrates. Such unprecedented discovery points to a new direction in the assessment of ADHD and suggest that further study of this receptor family may provide novel insights into the etiology and treatment of ADHD and other related psychiatric conditions. PMID:21184579

  10. Recent Advances in Research on Widow Spider Venoms and Toxins

    OpenAIRE

    Shuai Yan; Xianchun Wang

    2015-01-01

    Widow spiders have received much attention due to the frequently reported human and animal injures caused by them. Elucidation of the molecular composition and action mechanism of the venoms and toxins has vast implications in the treatment of latrodectism and in the neurobiology and pharmaceutical research. In recent years, the studies of the widow spider venoms and the venom toxins, particularly the α-latrotoxin, have achieved many new advances; however, the mechanism of action of the venom...

  11. The diet of the black widow spider Latrodectus mirabilis (Theridiidae in two cereal crops of central Argentina

    Directory of Open Access Journals (Sweden)

    Gabriel Pompozzi

    2013-12-01

    Full Text Available The spider Latrodectus mirabilis (Holmberg, 1876 is commonly found in cereals crops of central Argentina. We studied its diet composition at the field and capture rate on leaf-cutting ants based on laboratory experiments. This study comprises the first approach that documents the diet of L. mirabilis in wheat and oat fields of central Argentina. We identified 1,004 prey items collected from its webs during the last phenological stages of both cereal crops. The prey composition was variable but the spiders prey mainly on ants (Formicidae, Hymenoptera, who represented more than 86% of the total. Meanwhile, in the capture rate experiences we registered a high proportion of ants captured by spiders at the beginning of experiences, capturing the half of the ants from total in the first four hours. Summarizing, we reported a polyphagous diet of this spider species in wheat and oat fields. Ants were the most important prey item of this spider, as found in other Latrodectus spiders around the world.

  12. Recent Advances in Research on Widow Spider Venoms and Toxins.

    Science.gov (United States)

    Yan, Shuai; Wang, Xianchun

    2015-12-01

    Widow spiders have received much attention due to the frequently reported human and animal injures caused by them. Elucidation of the molecular composition and action mechanism of the venoms and toxins has vast implications in the treatment of latrodectism and in the neurobiology and pharmaceutical research. In recent years, the studies of the widow spider venoms and the venom toxins, particularly the α-latrotoxin, have achieved many new advances; however, the mechanism of action of the venom toxins has not been completely clear. The widow spider is different from many other venomous animals in that it has toxic components not only in the venom glands but also in other parts of the adult spider body, newborn spiderlings, and even the eggs. More recently, the molecular basis for the toxicity outside the venom glands has been systematically investigated, with four proteinaceous toxic components being purified and preliminarily characterized, which has expanded our understanding of the widow spider toxins. This review presents a glance at the recent advances in the study on the venoms and toxins from the Latrodectus species. PMID:26633495

  13. Establishment of the Brown Widow Spider (Araneae: Theridiidae) and Infestation of its Egg Sacs by a Parasitoid, Philolema latrodecti (Hymenoptera: Eurytomidae), in French Polynesia and the Cook Islands.

    Science.gov (United States)

    Marie, Jérôme; Vetter, Richard S

    2015-11-01

    This paper presents two newly established species for French Polynesia: the invasive brown widow spider, Latrodectus geometricus C. L. Koch, and its potential biocontrol agent, the parasitoid wasp, Philolema latrodecti (Fullaway). The brown widow spider was recorded from the island of Moorea in 2006 and, since that discovery, the occurrence of this species has expanded to two of the five archipelagos of French Polynesia including the main island of Tahiti and four of the Cook Islands. Although the tropical climate contributes to the establishment of L. geometricus, a biotic factor, P. latrodecti, may restrain population from demographic explosion. This eurytomid wasp is present in French Polynesia and is a parasitoid that has been used in biological control of the southern black widow Latrodectus mactans (F.) in Hawaii. This wasp could become a significant limiting factor for L. geometricus distribution on these islands, as it was found in 31% of the Tahitian brown widow spider egg sacs that were dissected. However, thus far, the wasp was only found on Tahiti in association with the brown widow spider. Although the brown widow is generally considered to be less toxic than its black widow relatives, it remains of medical concern in French Polynesia because reactions to its bites can, at times, be severe. The spider remains of public concern because it is a novel species; it has the word widow in its name and dark morphs are mistaken as black widows. PMID:26336266

  14. Chandra Observations of Black-Widow Pulsars

    CERN Document Server

    Gentile, Peter; Roberts, Mallory; Camilo, Fernando; Hessels, Jason; Kerr, Matthew; Ransom, Scott; Ray, Paul; Stairs, Ingrid

    2012-01-01

    We describe the first X-ray observations of binary millisecond pulsars PSRs J0023+0923, J1810+1744, J2215+5135, and J2256-1024. All four are Fermi gamma-ray sources and three are 'black-widow' pulsars, with companions of mass < 0.1 solar masses. Data were taken using the Chandra X-Ray Observatory and covered a full binary orbit for each pulsar. Two pulsars, PSRs J2215+5135 and J2256-1024, show significant orbital variability and X-ray flux minima at the times of eclipses observed at radio wavelengths. This phenomenon is consistent with intrabinary shock emission characteristic of black-widow pulsars. The other two pulsars, PSRs J0023+0923 and J1810+1744, do not demonstrate significant variability, but are fainter than the other two sources. Spectral fits yield power-law indices that range from 1.4 to 2.3 and blackbody temperatures in the hundreds of eV. The spectrum for PSR J2215+5135 shows a significant hard X-ray component (41% of counts are above 2 keV), which is additional evidence for the presence of ...

  15. Dramatic expansion of the black widow toxin arsenal uncovered by multi-tissue transcriptomics and venom proteomics

    OpenAIRE

    Haney, Robert A.; Ayoub, Nadia A; Clarke, Thomas H; Cheryl Y Hayashi; Garb, Jessica E.

    2014-01-01

    Background Animal venoms attract enormous interest given their potential for pharmacological discovery and understanding the evolution of natural chemistries. Next-generation transcriptomics and proteomics provide unparalleled, but underexploited, capabilities for venom characterization. We combined multi-tissue RNA-Seq with mass spectrometry and bioinformatic analyses to determine venom gland specific transcripts and venom proteins from the Western black widow spider (Latrodectus hesperus) a...

  16. 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.

  17. Systematics, Bioecology, and Medical Importance of Widow Spiders (Lathrodectus spp. in Khorasan Province, Iran

    Directory of Open Access Journals (Sweden)

    J Rafijenad

    2007-05-01

    Full Text Available Following the hospitalization of 195 individuals due to the spider bite in 1995 and three cases of recorded death in the year of 1993 which were referred to Emam Reza Hospital in Mashad, the present study was undertaken on bionomics and medical importance of Lathrodectus spp in Khorasan Province, during 1995-2005. A total cases of 195 bites were studied composing of 70.8 % males and 29.2% females. The most prevalence cases were observed in mid age (20-55 years old and par¬ticularly among farmers (36.4%. A total number of 216 adult widow spiders and 258 egg sacs were collected from their habitats in different localities of 15 counties in the province. The following species have been recognized: Lathrodectus tredecimgottatus (62%, L. dahli (32%, L. geometricus (5% and L. pallidus (1%. Here is the first report on the occurrence of males of L. pallidus as well as both sexes of L. trdecimgottatus and L. geometricus in the country. The sex ratio among collected specimens was 88% and 12% female and male, respectively. Summer provides the most suitable and favorable climatic condition for the activities of these spiders. However 65% of spiders were collected in this season. Among different cit¬ies, Mashad had (60% the most reported cases in the study area. Foot was more injured than other parts. 96.5% of pa¬tients exhib¬ited localized pain from which only 2% had no pain in the bitten part and 87% had a generalized pain in whole body.

  18. Systematics, Bioecology, and Medical Importance of Widow Spiders (Lathrodectus spp. in Khorasan Province, Iran

    Directory of Open Access Journals (Sweden)

    J Rafijenad

    2007-06-01

    Full Text Available Following the hospitalization of 195 individuals due to the spider bite in 1995 and three cases of recorded death in the year of 1993 which were referred to Emam Reza Hospital in Mashad, the present study was undertaken on bionomics and medical importance of Lathrodectus spp in Khorasan Province, during 1995-2005. A total cases of 195 bites were studied composing of 70.8 % males and 29.2% females. The most prevalence cases were observed in mid age (20-55 years old and par¬ticularly among farmers (36.4%. A total number of 216 adult widow spiders and 258 egg sacs were collected from their habitats in different localities of 15 counties in the province. The following species have been recognized: Lathrodectus tredecimgottatus (62%, L. dahli (32%, L. geometricus (5% and L. pallidus (1%. Here is the first report on the occurrence of males of L. pallidus as well as both sexes of L. trdecimgottatus and L. geometricus in the country. The sex ratio among collected specimens was 88% and 12% female and male, respectively. Summer provides the most suitable and favorable climatic condition for the activities of these spiders. However 65% of spiders were collected in this season. Among different cit¬ies, Mashad had (60% the most reported cases in the study area. Foot was more injured than other parts. 96.5% of pa¬tients exhib¬ited localized pain from which only 2% had no pain in the bitten part and 87% had a generalized pain in whole body.

  19. Intra-Binary Shock Heating of Black Widow Companions

    CERN Document Server

    Romani, Roger W

    2016-01-01

    The low mass companions of evaporating binary pulsars (black widows and their ilk) are strongly heated on the side facing the pulsar. However in high-quality photometric and spectroscopic data the heating pattern does not match that expected for direct pulsar illumination. Here we explore heating mediated by an intra-binary shock (IBS). We develop a simple analytic model and implement it in the popular `ICARUS' light curve code. The model is parameterized by the wind momentum ratio beta and velocity v_Rel v_orb and assumes that the reprocessed pulsar wind emits prompt particles or radiation to heat the companion surface. We illustrate an interesting range of light curve asymmetries controlled by these parameters. The code also computes the IBS synchrotron emission pattern, and thus can model black widow X-ray light curves. As a test we apply the results to the high quality asymmetric optical light curves of PSR J2215+5135; the resulting fit gives a substantial improvement upon direct heating models and produc...

  20. Intra-binary Shock Heating of Black Widow Companions

    Science.gov (United States)

    Romani, Roger W.; Sanchez, Nicolas

    2016-09-01

    The low-mass companions of evaporating binary pulsars (black widows and similar) are strongly heated on the side facing the pulsar. However, in high-quality photometric and spectroscopic data, the heating pattern does not match that expected for direct pulsar illumination. Here we explore a model where the pulsar power is intercepted by an intra-binary shock (IBS) before heating the low-mass companion. We develop a simple analytic model and implement it in the popular “ICARUS” light curve code. The model is parameterized by the wind momentum ratio β and the companion wind speed {f}v{v}{{orb}}, and assumes that the reprocessed pulsar wind emits prompt particles or radiation to heat the companion surface. We illustrate an interesting range of light curve asymmetries controlled by these parameters. The code also computes the IBS synchrotron emission pattern, and thus can model black widow X-ray light curves. As a test, we apply the results to the high-quality asymmetric optical light curves of PSR J2215+5135; the resulting fit gives a substantial improvement upon direct heating models and produces an X-ray light curve consistent with that seen. The IBS model parameters imply that at the present loss rate, the companion evaporation has a characteristic timescale of {τ }{{evap}}≈ 150 Myr. Still, the model is not fully satisfactory, indicating that there are additional unmodeled physical effects.

  1. X-Ray Observations of Black Widow Pulsars

    CERN Document Server

    Gentile, P; McLaughlin, M; Camilo, F; Hessels, J; Kerr, M; Ransom, S; Ray, P; Stairs, I

    2013-01-01

    We describe the first X-ray observations of five short orbital period ($P_B < 1$ day), $\\gamma$-ray emitting, binary millisecond pulsars. Four of these, PSRs J0023+0923, J1124$-$3653, J1810+1744, and J2256$-$1024 are `black-widow' pulsars, with degenerate companions of mass $\\ll0.1 M_{\\odot}$, three of which exhibit radio eclipses. The fifth source, PSR J2215+5135, is an eclipsing `redback' with a near Roche-lobe filling $\\sim$0.2 solar mass non-degenerate companion. Data were taken using the \\textit{Chandra X-Ray Observatory} and covered a full binary orbit for each pulsar. Two pulsars, PSRs J2215+5135 and J2256$-$1024, show significant orbital variability while PSR J1124$-$3653 shows marginal orbital variability. The lightcurves for these three pulsars have X-ray flux minima coinciding with the phases of the radio eclipses. This phenomenon is consistent with an intrabinary shock emission interpretation for the X-rays. The other two pulsars, PSRs J0023+0923 and J1810+1744, are fainter and do not demonstra...

  2. Radio Timing and Analysis of Black Widow Pulsar J2256-1024

    Science.gov (United States)

    Crowter, Kathryn; Stairs, Ingrid H.; McPhee, Christie A.; Archibald, Anne M.; Boyles, Jason; Hessels, Jason; Kaspi, Victoria M.; Kondratiev, Vlad I.; Lorimer, Duncan; Lynch, Ryan S.; McLaughlin, Maura; Pennucci, Timothy; Ransom, Scott M.; Roberts, Mallory; Stovall, Kevin; van Leeuwen, Joeri

    2015-01-01

    Pulsar J2256-1024, discovered in a 350MHz GBT drift-scan survey and subsequently detected by Fermi-LAT, is a black widow millisecond pulsar in an eclipsing binary system. Black widow pulsars have a rather interesting history. They started life in a binary system, were then spun up by their companions into millisecond pulsars but at some point started ablating those companions, slowly destroying them - thus the moniker "black widow". They are characterized by relatively short orbital periods, in this case 5.1 hours, a low companion mass and, if the inclination angle is right, eclipses. For J2256-1024 we see very clear radio eclipses. Black widow systems used to be few and far between but are now more common with at least 18 currently known. Black widows are interesting for a variety of reasons. They provide potential insight into the formation of isolated millisecond pulsars which must have formed in a binary but are now seen alone, and in eclipsing systems pulses travel through the magnetosphere of the companion providing a probe of that region. Here we present timing and polarization results for J2256-1024 based on radio observations with the GBT.

  3. Formation of black widows and redbacks -- two distinct populations of eclipsing binary millisecond pulsars

    CERN Document Server

    Chen, Hai-Liang; Tauris, Thomas M; Han, Zhanwen

    2013-01-01

    Eclipsing binary millisecond pulsars (the so-called black widows and redbacks) can provide important information about accretion history, pulsar irradiation of their companion stars and the evolutionary link between accreting X-ray pulsars and isolated millisecond pulsars. However, the formation of such systems is not well understood, nor the difference in progenitor evolution between the two populations of black widows and redbacks. Whereas both populations have orbital periods between $0.1-1.0\\;{\\rm days}$ their companion masses differ by an order of magnitude. In this paper, we investigate the formation of these systems via evolution of converging low-mass X-ray binaries by employing the MESA stellar evolution code. Our results confirm that one can explain the formation of most of these eclipsing binary millisecond pulsars using this scenario. More notably, we find that the determining factor for producing either black widows or redbacks is the efficiency of the irradiation process, such that the redbacks ...

  4. Efficacy of Several Pesticide Products on Brown Widow Spider (Araneae: Theridiidae) Egg Sacs and Their Penetration Through the Egg Sac Silk.

    Science.gov (United States)

    Vetter, Richard S; Tarango, Jacob; Campbell, Kathleen A; Tham, Christine; Hayashi, Cheryl Y; Choe, Dong-Hwan

    2016-02-01

    Information on pesticide effects on spiders is less common than for insects; similar information for spider egg sacs is scarcer in the open literature. Spider egg sacs are typically covered with a protective silk layer. When pesticides are directly applied to egg sacs, the silk might prevent active ingredients from reaching the eggs, blocking their insecticidal effect. We investigated the impact of six water-based pesticide sprays and four oil-based aerosol products against egg sacs of brown widow spiders, Latrodectus geometricus C. L. Koch. All water-based spray products except one failed to provide significant mortality to egg sacs, resulting in successful spiderling emergence from treated egg sacs at a similar rate to untreated egg sacs. In contrast to water-based sprays, oil-based aerosols provided almost complete control, with 94-100% prevention of spiderling emergence. Penetration studies using colored pesticide products indicated that oil-based aerosols were significantly more effective in penetrating egg sac silk than were the water-based sprays, delivering the active ingredients on most (>99%) of the eggs inside the sac. The ability of pesticides to penetrate spider egg sac silk and deliver lethal doses of active ingredients to the eggs is discussed in relation to the chemical nature of egg sac silk proteins. Our study suggests that pest management procedures primarily relying on perimeter application of water-based sprays might not provide satisfactory control of brown widow spider eggs. Determination of the most effective active ingredients and carrier characteristics warrant further research to provide more effective control options for spider egg sacs. PMID:26530954

  5. 21-year timing of the black-widow pulsar J2051-0827

    CERN Document Server

    Shaifullah, G; Freire, P C C; Tauris, T M; Wex, N; Osłowski, S; Stappers, B W; Bassa, C G; Caballero, R N; Champion, D J; Cognard, I; Desvignes, G; Graikou, E; Guillemot, L; Janssen, G H; Jessner, A; Jordan, C; Karuppusamy, R; Kramer, M; Lazaridis, K; Lazarus, P; Lyne, A G; McKee, J W; Perrodin, D; Possenti, A; Tiburzi, C

    2016-01-01

    Timing results for the black-widow pulsar J2051-0827 are presented, using a 21-year dataset from four European Pulsar Timing Array telescopes and the Parkes radio telescope. This dataset, which is the longest published to date for a black-widow system, allows for an improved analysis that addresses previously unknown biases. While secular variations, as identified in previous analyses, are recovered, short-term variations are detected for the first time. Concurrently, a significant decrease of approx. 2.5x10-3 cm-3 pc in the dispersion measure associated with PSR J2051-0827 is measured for the first time and improvements are also made to estimates of the proper motion. Finally, PSR J2051-0827 is shown to have entered a relatively stable state suggesting the possibility of its eventual inclusion in pulsar timing arrays.

  6. The Feasibility of Using Black Widow Pulsars in Pulsar Timing Arrays for Gravitational Wave Detection

    CERN Document Server

    Bochenek, Christopher; Demorest, Paul

    2015-01-01

    In the past five years, approximately one third of the 65 pulsars discovered by radio observations of Fermi unassociated sources are black widow pulsars (BWPs). BWPs are binary millisecond pulsars with companion masses ranging from 0.01-0.1 solar masses which often exhibit radio eclipses. The bloated companions in BWP systems exert small torques on the system causing the orbit to change on small but measurable time scales. Because adding parameters to a timing model reduces sensitivity to a gravitational wave (GW) signal, the need to fit many orbital frequency derivatives to the timing data is potentially problematic for using BWPs to detect GWs with pulsar timing arrays. Using simulated data with up to four orbital frequency derivatives, we show that fitting for orbital frequency derivatives absorbs less than 5% of the low frequency spectrum expected from a stochastic gravitational wave background signal. Furthermore, this result does not change with orbital period. Therefore, we suggest that if timing syste...

  7. Discovery of an Unidentified Fermi Object as a Black Widow-Like Millisecond Pulsar

    Science.gov (United States)

    Kong, A. K. H.; Huang, R. H. H.; Cheng, K. S.; Takata, J.; Yatsu, Y.; Cheung, C. C.; Donato, D.; Lin, L. C. C.; Kataoka, J.; Takahashi, Y.; Maeda, K.; Hui, C. Y.; Tam, P. H. T.

    2012-01-01

    The Fermi Gamma-ray Space Telescope has revolutionized our knowledge of the gamma-ray pulsar population, leading to the discovery of almost 100 gamma-ray pulsars and dozens of gamma-ray millisecond pulsars (MSPs). Although the outer-gap model predicts different sites of emission for the radio and gamma-ray pulsars, until now all of the known gamma-ray MSPs have been visible in the radio. Here we report the discovery of a radio-quiet" gamma-ray emitting MSP candidate by using Fermi, Chandra, Swift, and optical observations. The X-ray and gamma-ray properties of the source are consistent with known gamma-ray pulsars. We also found a 4.63-hr orbital period in optical and X-ray data. We suggest that the source is a black widow-like MSP with a approx. 0.1 Stellar Mass late-type companion star. Based on the profile of the optical and X-ray light-curves, the companion star is believed to be heated by the pulsar while the X-ray emissions originate from pulsar magnetosphere and/or from intra-binary shock. No radio detection of the source has been reported yet and although no gamma-ray/radio pulsation has been found, we estimated that the spin period of the MSP is approx. 3-5 ms based on the inferred gamma-ray luminosity.

  8. Multi-wavelength observations of the black widow pulsar 2FGL J2339.6-0532 with OISTER and Suzaku

    CERN Document Server

    Yatsu, Yoichi; Takahashi, Yosuke; Tachibana, Yutaro; Kawai, Nobuyuki; Shibata, Shimpei; Pike, Sean; Yoshii, Taketoshi; Arimoto, Makoto; Saito, Yoshihiko; NakamorI, Takeshi; Sekiguchi, Kazuhiro; Kuroda, Daisuke; Yanagisawa, Kenshi; Hanayama, Hidekazu; Watanabe, Makoto; Hamamoto, Ko; Nakao, Hikaru; Ozaki, Akihito; Motohara, Kentaro; Konishi, Masahiro; Tateuchi, Ken; Matsunaga, Noriyuki; Morokuma, Tomoki; Nagayama, Takahiro; Murata, Katsuhiro; Akitaya, Hiroshi; Yoshida, Michitoshi; Ali, Gamal B; Mohamed, A Essam; Isogai, Mizuki; Arai, Akira; Takahashi, Hidenori; Hashimoto, Osamu; Miyanoshita, Ryo; Omodaka, Toshihiro; Takahashi, Jun; Tokimasa, Noritaka; Matsuda, Kentaro; Okumura, Shin-Ichiro; Nishiyama, Kota; Urakawa, Seitaro; Nogami, Daisaku; Oasa, Yumiko

    2015-01-01

    Multi-wavelength observations of the black-widow binary system 2FGL J2339.6-0532 are reported. The Fermi gamma-ray source 2FGL J2339.6-0532 was recently categorized as a black widow in which a recycled millisecond pulsar (MSP) is evaporating up the companion star with its powerful pulsar wind. Our optical observations show clear sinusoidal light curves due to the asymmetric temperature distribution of the companion star. Assuming a simple geometry, we constrained the range of the inclination angle of the binary system to 52$^{\\circ}$ < i < 59$^{\\circ}$, which enables us to discuss the interaction between the pulsar wind and the companion in detail. The X-ray spectrum consists of two components: a soft, steady component that seems to originate from the surface of the MSP, and a hard variable component from the wind-termination shock near the companion star. The measured X-ray luminosity is comparable to the bolometric luminosity of the companion, meaning that the heating efficiency is less than 0.5. In t...

  9. Habitat preferences, diet, feeding strategy and social organisation of the black spider monkey (Ateles panisius paniscus L.) in Surinam

    OpenAIRE

    Roosmalen, van, J.

    1980-01-01

    This study describes habitat choice of the Surinam black spider monkey ( Atelespaniscuspaniscus ) and clarifies complex temporal and spatial effects of food sources on the behaviour of a group of spider monkeys in a 350 ha study area in central Surinam in terms of food category, food plant identity and phenology, and in terms of quantity, density and dispersion of the most important of these food sources. It recognizes the fundamental importance of mature-fruit feeding to spider-monkey foragi...

  10. Habitat preferences, diet, feeding strategy and social organisation of the black spider monkey (Ateles panisius paniscus L.) in Surinam

    NARCIS (Netherlands)

    Roosmalen, van M.G.M.

    1980-01-01

    This study describes habitat choice of the Surinam black spider monkey ( Atelespaniscuspaniscus ) and clarifies complex temporal and spatial effects of food sources on the behaviour of a group of spider monkeys in a 350 ha study area in central Surinam in terms of food category,

  11. X-ray emission from J1446-4701, J1311-3430 and other black widow pulsars

    CERN Document Server

    Arumugasamy, Prakash; Garmire, Gordon P

    2015-01-01

    We present the results of detailed X-ray analysis of two black-widow pulsars (BWPs), J1446-4701 and J1311-3430. PSR J1446-4701 is a BWP with orbital parameters near the median values of the sample of known BWPs. Its X-ray emission detected by $XMM-Newton$ is well characterized by a soft power-law (PL) spectrum (photon index $\\Gamma \\approx 3$), and it shows no significant orbital modulations. In view of a lack of radio eclipses and an optical non-detection, the system most likely has a low orbital inclination. PSR J1311-3430 is an extreme BWP with a very compact orbit and the lowest minimum mass companion. Our $Chandra$ data confirm the hard, $\\Gamma \\approx 1.3$, emission seen in previous observations. Through phase-restricted spectral analysis, we found a hint ($\\sim 2.6 \\sigma$) of spectral hardening around pulsar inferior conjunction. We also provide a uniform analysis of the 12 BWPs observed with $Chandra$ and compare their X-ray properties. Pulsars with soft, $\\Gamma > 2.5$, emission seem to have lower ...

  12. Orbital Phase-Resolved X-ray Observations of the Black-Widow Pulsar J1446-4701

    Science.gov (United States)

    Arumugasamy, Prakash; Pavlov, G. G.

    2014-01-01

    PSR J1446--4701 is a recently discovered radio and gamma-ray recycled pulsar in a tight binary (binary period P_b = 6.6 hr, a sin i = 1.7 R_⊙). The relativistic pulsar wind at such close proximity is expected to evaporate the low mass companion (M_{min}= 0.019 M_⊙), which should lead to an orbital phase dependence of the multiwavelength emission of this Black Widow pulsar (BWP) system. We observed the system with XMM-Newton EPIC (0.3--10 keV) and Optical Monitor (B,V) for 60 ks, covering about 2.5 binary orbits, to look for the orbital variability of its flux and spectrum. The EPIC data do not show a significant orbital variability of the flux, perhaps due to a low orbital inclination. However, the orbital phase-resolved spectral analysis allowed us to separate two spectral components: thermal pulsar polar-cap emission (kT=0.18±0.02 keV, R=216±60 m), detected throughout the orbit, and a hard power-law component (Γ = 1.4±0.6), detected only for the half-orbit around superior conjunction of the pulsar. We infer the hard non-thermal component to be the intra-binary shock emission. We did not detect an optical counterpart with the optical monitor, which sets some strong constraints on the companion. In the context of similar BWPs, we discuss the pulsar's high energy emission characteristics and intra-binary shock energetics.

  13. Spider Invasion Across the Galaxy

    Science.gov (United States)

    Hui, Chung-Yue

    2014-06-01

    The nature of the exotic stellar corpses which reincarnate by consuming their companion is reviewed. Apart from sucking life from their partners, they are actually eating the doomed companions away by their deadly and powerful particle/radiation beams. Such situation resembles that a female ¡°black widow¡± spider that eats its mate after mating. These celestial zombies are called - Millisecond pulsars (MSPs). In this review article, I will focus on the effort of Fermi Asian Network (FAN) in exploring these intricating objects over the last five years. Two special classes of MSPs are particularly striking. Since Fermi Gamma-ray Space Telescope has started surveying the gamma?ray sky, the population of ¡°black widows¡± has been boosted. Another dramatic class is so-called ¡°redbacks¡± (Australian cousin of ¡°black widows¡±) which has just emerged in the last few years. These MSPs provide us with a long-sought missing link in understanding the transition between accretion-powered and rotation-powered systems. The strategy of hunting MSPs through mulitwavelength observations of the unidentified Fermi objects is also reviewed.

  14. Radio timing and optical photometry of the black widow system PSR J1518+0204C in the globular cluster M5

    Energy Technology Data Exchange (ETDEWEB)

    Pallanca, C.; Ferraro, F. R.; Dalessandro, E.; Lanzoni, B. [Dipartimento di Fisica e Astronomia, Università di Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy); Ransom, S. M. [National Radio Astronomy Observatory (NRAO), 520 Edgemont Road, Charlottesville, VA 22901 (United States); Hessels, J. W. T. [ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo (Netherlands); Stairs, I. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T1Z1 (Canada); Freire, P. C. C. [Max-Planck-Institute für Radioastronomie, D-53121 Bonn (Germany)

    2014-11-01

    We report on the determination of astrometric, spin, and orbital parameters for PSR J1518+0204C, a 'black widow' binary millisecond pulsar in the globular cluster (GC) M5. The accurate position and orbital parameters obtained from radio timing allowed us to search for the optical companion. By using WFC3/Hubble Space Telescope images, we identified a very faint variable star (m{sub F390W} ≳ 24.8, m{sub F606W} ≳ 24.3, m{sub F814W} ≳ 23.1) located at only 0.''25 from the pulsar's timing position. Due to its strong variability, this star is visible only in a subsample of images. However, the light curve obtained folding the available data with the orbital parameters of the pulsar shows a maximum at the pulsar inferior conjunction and a possible minimum at the pulsar superior conjunction. Furthermore, the shape of the optical modulation indicates a heating process possibly due to the pulsar wind. This is the first identification of an optical companion to a black widow pulsar in the dense stellar environment of a GC.

  15. Radio Timing and Optical Photometry of the Black Widow System PSR J1953+1846A in the Globular Cluster M71

    CERN Document Server

    Cadelano, M; Ferraro, F R; Stairs, I; Ransom, S M; Dalessandro, E; Lanzoni, B; Hessels, J W T; Freire, P C C

    2015-01-01

    We report on the determination of the astrometric, spin and orbital parameters for PSR J1953+1846A, a "black widow" binary millisecond pulsar in the globular cluster M71. By using the accurate position and orbital parameters obtained from radio timing, we identified the optical companion in ACS/Hubble Space Telescope images. It turns out to be a faint (m_F606W>=24, m_F814W>=23) and variable star located at only ~0.06" from the pulsar timing position. The light curve shows a maximum at the pulsar inferior conjunction and a minimum at the pulsar superior conjunction, thus confirming the association with the system. The shape of the optical modulation suggests that the companion star is heated, likely by the pulsar wind. The comparison with the X-ray light curve possibly suggests the presence of an intra-binary shock due to the interaction between the pulsar wind and the material released by the companion. This is the second identification (after COM-M5C) of an optical companion to a black widow pulsar in a glob...

  16. Radio timing and optical photometry of the black widow system PSR J1518+0204C in the globular cluster M5

    CERN Document Server

    Pallanca, C; Ferraro, F R; Dalessandro, E; Lanzoni, B; Hessels, J W T; Stairs, I; Freire, P C C

    2014-01-01

    We report on the determination of astrometric, spin and orbital parameters for PSR J1518+0204C, a "black widow" binary millisecond pulsar in the globular cluster M5. The accurate position and orbital parameters obtained from radio timing allowed us to search for the optical companion. By using WFC3/HST images we identified a very faint variable star (m_F390W > 24.8, m_F606W > 24.3, m_F814W > 23.1) located at only 0.25" from the pulsar's timing position. Due to its strong variability, this star is visible only in a sub-sample of images. However, the light curve obtained folding the available data with the orbital parameters of the pulsar shows a maximum at the pulsar inferior conjunction and a possible minimum at the pulsar superior conjunction. Furthermore, the shape of the optical modulation indicates a heating process possibly due to the pulsar wind. This is the first identification of an optical companion to a black widow pulsar in the dense stellar environment of a globular cluster.

  17. Radio timing and optical photometry of the black widow system PSR J1518+0204C in the globular cluster M5

    International Nuclear Information System (INIS)

    We report on the determination of astrometric, spin, and orbital parameters for PSR J1518+0204C, a 'black widow' binary millisecond pulsar in the globular cluster (GC) M5. The accurate position and orbital parameters obtained from radio timing allowed us to search for the optical companion. By using WFC3/Hubble Space Telescope images, we identified a very faint variable star (mF390W ≳ 24.8, mF606W ≳ 24.3, mF814W ≳ 23.1) located at only 0.''25 from the pulsar's timing position. Due to its strong variability, this star is visible only in a subsample of images. However, the light curve obtained folding the available data with the orbital parameters of the pulsar shows a maximum at the pulsar inferior conjunction and a possible minimum at the pulsar superior conjunction. Furthermore, the shape of the optical modulation indicates a heating process possibly due to the pulsar wind. This is the first identification of an optical companion to a black widow pulsar in the dense stellar environment of a GC.

  18. Radio Timing and Optical Photometry of the Black Widow System PSR J1953+1846A in the Globular Cluster M71

    Science.gov (United States)

    Cadelano, M.; Pallanca, C.; Ferraro, F. R.; Stairs, I.; Ransom, S. M.; Dalessandro, E.; Lanzoni, B.; Hessels, J. W. T.; Freire, P. C. C.

    2015-07-01

    We report on the determination of the astrometric, spin, and orbital parameters for PSR J1953+1846 A, a “black widow” binary millisecond pulsar in the globular cluster M71. By using the accurate position and orbital parameters obtained from radio timing, we identified the optical companion in Advanced Camera for Surveys/Hubble Space Telescope images. It turns out to be a faint ({m}{{F}606{{W}}}≳ 24, {m}{{F}814{{W}}}≳ 23) and variable star located at only ˜0.″06 from the pulsar timing position. The light curve shows a maximum at the pulsar inferior conjunction and a minimum at the pulsar superior conjunction, thus confirming the association with the system. The shape of the optical modulation suggests that the companion star is heated, likely by the pulsar wind. The comparison with the X-ray light curve possibly suggests the presence of an intra-binary shock due to the interaction between the pulsar wind and the material released by the companion. This is the second identification (after COM-M5C) of an optical companion to a black widow pulsar in a globular cluster. Interestingly, the two companions show a similar light curve and share the same position in the color-magnitude diagram. Based on observations collected with the NASA/ESA HST (Prop. 12932), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555.

  19. Coagulopathy after spider bites in a six-year-old boy

    Directory of Open Access Journals (Sweden)

    Ansari SH.

    2008-06-01

    Full Text Available Background: Spider bites are common in most parts of the world. In some areas, where snake or scorpion bites are common, spider bites may not be considered a significant problem by the general public and those who have been bitten by spiders may not go to a hospital. However, significant problems are observed in the victims of certain species of spiders including: widow spider (of the genus Latrodectus, including the black widow and brown spiders (of the genus Loxosceles, such as the brown recluse. Case: We report a six-year-old boy, admitted to the hospital two weeks after suffering a spider bite. The patient presented with a severe nose bleed, ecchymosis and purpura, as well as anemia, indicating a clotting disorder. Laboratory results revealed abnormal values for prothrombin time (PT >50 sec, partial thromboplastin time (PTT >120 min and fibrinogen = 0 mg/dl, whereas factor VIII was normal according to a mixing study, with a normal platelet count of 350,000/µl. The patient was managed with fresh frozen plasma every 12 h, and was discharged one week after hospital admission. At present, the patient is well with more normal laboratory results one month after treatment: PT=13.4 sec, PTT= 34 sec, fibrinogen=105 mg/dl.         Conclusions: Although spider bites are uncommon in Iran, severe systemic reactions may occur in the pediatric population requiring admission to the pediatric intensive care unit. These systemic reactions may include hemolytic anemia coagulopathy and renal failure.

  20. Evidence for a Massive Neutron Star from a Radial-Velocity Study of the Companion to the Black Widow Pulsar PSR B1957+20

    CERN Document Server

    van Kerkwijk, M H; Kulkarni, S R

    2010-01-01

    The most massive neutron stars constrain the behavior of ultra-dense matter, with larger masses possible only for increasingly stiff equations of state. Here, we present evidence that the black widow pulsar, PSR B1957+20, has a high mass. We took spectra of its strongly irradiated companion and found an observed radial-velocity amplitude of K_obs=324+/-3 km/s. Correcting this for the fact that, due to the irradiation, the center of light lies inward relative to the center of mass, we infer a true radial-velocity amplitude of K_2=353+/-4 km/s and a mass ratio q=M_PSR/M_2=69.2+/-0.8. Combined with the inclination i=65+/-2 deg inferred from models of the lightcurve, our best-fit pulsar mass is M_PSR=2.40+/-0.12 M_sun. We discuss possible systematic uncertainties, in particular in the lightcurve modeling. Taking an upper limit of i343 km/s (q>67.3), we infer a lower limit to the pulsar mass of M_PSR>1.66 M_sun.

  1. 20 CFR 222.24 - Relationship as remarried widow(er).

    Science.gov (United States)

    2010-04-01

    ... FAMILY RELATIONSHIPS Relationship as Divorced Spouse, Surviving Divorced Spouse, or Remarried Widow(er) § 222.24 Relationship as remarried widow(er). (a) New eligibility. A claimant will have the relationship... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Relationship as remarried widow(er)....

  2. Tarantula spider

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002855.htm Tarantula spider bite To use the sharing features on ... JavaScript. This article describes the effects of a tarantula spider bite. This article is for information only. ...

  3. Rapid Coeval Black Hole and Host Galaxy Growth in MRC 1138-262: The Hungry Spider

    CERN Document Server

    Seymour, N; De Breuck, C; Barthel, P; Coia, D; Conversi, L; Dannerbauer, H; Dey, A; Dickinson, M; Drouart, G; Galametz, A; Greve, T R; Haas, M; Hatch, N; Ibar, E; Ivison, R; Jarvis, M; Kovacs, A; Kurk, J; Lehnert, M; Miley, G; Nesvadba, N; Rawlings, J I; Rettura, A; Rottgering, H; Rocca-Volmerange, B; Sanchez-Portal, M; Santos, J S; Stern, D; Stevens, J; Valtchanov, I; Vernet, J; Wylezalek, D

    2012-01-01

    We present a detailed study of the infrared spectral energy distribution of the high-redshift radio galaxy MRC 1138-26 at z = 2.156, also known as the Spiderweb Galaxy. By combining photometry from Spitzer, Herschel and LABOCA we fit the rest-frame 5-300 um emission using a two component, starburst and active galactic nucleus (AGN), model. The total infrared (8 - 1000 um) luminosity of this galaxy is (1.97+/-0.28)x10^13 Lsun with (1.17+/-0.27) and (0.79+/-0.09)x10^13 Lsun due to the AGN and starburst components respectively. The high derived AGN accretion rate of \\sim20% Eddington, and the measured star formation rate (SFR) of 1390pm150 Msun/yr, suggest that this massive system is in a special phase of rapid central black hole and host galaxy growth, likely caused by a gas rich merger in a dense environment. The accretion rate is sufficient to power both the jets and the previously observed large outflow. The high SFR and strong outflow suggest this galaxy could potentially exhaust its fuel for stellar growth...

  4. Venomous Spiders

    Science.gov (United States)

    ... and Scorpions Poisonous Plants Venomous Spiders Venomous Snakes Vector-Borne Diseases Mosquito-Borne Diseases Tick-Borne Diseases Lyme Disease ... and Scorpions Poisonous Plants Venomous Spiders Venomous Snakes Vector-Borne Diseases Mosquito-Borne Diseases Tick-Borne Diseases Lyme Disease ...

  5. Neurotoxic activity and ultrastructural changes in muscles caused by the brown widow spider Latrodectus geometricus venom Actividad neurotóxica y cambios ultraestructurales en musculos causados por el veneno de la araña viuda marrón Latrodectus geometricus

    Directory of Open Access Journals (Sweden)

    Matias Reyes-Lugo

    2009-04-01

    Full Text Available Brown widow spider (Latrodectus geometricus venom (BrWSV produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and ~ 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 µg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study is the first

  6. 20 CFR 218.44 - When a remarried widow(er) annuity ends.

    Science.gov (United States)

    2010-04-01

    ... the month in which the remarried widow(er) attains full retirement age (the disability annuitant then... widow attains full retirement age (the annuitant then becomes entitled to an annuity based upon age). ....44 Section 218.44 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE...

  7. SPIDER SILK

    Directory of Open Access Journals (Sweden)

    PORAV Viorica

    2014-05-01

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

  8. 20 CFR 222.10 - When determinations of relationship as wife, husband, widow or widower of employee are made.

    Science.gov (United States)

    2010-04-01

    ... RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT FAMILY RELATIONSHIPS Relationship as Wife, Husband, or Widow(er) § 222.10 When determinations of relationship as wife, husband, widow or widower of... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false When determinations of relationship as...

  9. Function of bright coloration in the wasp spider Argiope bruennichi (Araneae: Araneidae)

    OpenAIRE

    Alex A Bush; Yu, Douglas W; Marie E Herberstein

    2008-01-01

    There are two major competing explanations for the counter-intuitive presence of bright coloration in certain orb-web spiders. Bright coloration could lure insect prey to the web vicinity, increasing the spider's foraging success. Alternatively, the markings could function as disruptive camouflage, making it difficult for the insect prey to distinguish spiders from background colour variation. We measured the prey capture rates of wasp spiders, Argiope bruennichi, that were blacked out, shiel...

  10. 20 CFR 404.346 - Your relationship as wife, husband, widow, or widower based upon a deemed valid marriage.

    Science.gov (United States)

    2010-04-01

    ... widower based upon a deemed valid marriage. 404.346 Section 404.346 Employees' Benefits SOCIAL SECURITY... relationship as wife, husband, widow, or widower based upon a deemed valid marriage. (a) General. If your... explained in § 404.345, you may be eligible for benefits based upon a deemed valid marriage. You will...

  11. African widows: anthropological and historical perspectives.

    Science.gov (United States)

    Cattell, Maria G

    2003-01-01

    Variety characterizes widows' experiences around the world and in Africa south of the Sahara. This article explores the socioeconomic and cultural contexts of African widowhood, using anthropological studies in a number of African societies, including the author's research among Abaluyia of western Kenya. Some features of African widowhood are characteristic of African women's lives regardless of their marital status: their embeddedness in kinship systems and dependence on those systems for claims to productive resources, their economic self-reliance (which does not mean prosperity), strongly gendered divisions of labor, and the pervasiveness of patriarchal gender relations. Other features are specific to widowhood, including remarriage, issues of personal autonomy, and loss of status, access to productive resources and social support. Colonial and postcolonial historical transformations, including Africa's current dire economic situation and the AIDS epidemic, are considered in relation to widows' lives. An interesting question (given the theme of this edited volume) is whether a husband' s death puts African widows "on their own again," and whether, given African systems of kinship and marriage, most African women (and indeed men, too) can ever be said to be "on their own." PMID:14604001

  12. Function of bright coloration in the wasp spider Argiope bruennichi (Araneae: Araneidae).

    Science.gov (United States)

    Bush, Alex A; Yu, Douglas W; Herberstein, Marie E

    2008-06-01

    There are two major competing explanations for the counter-intuitive presence of bright coloration in certain orb-web spiders. Bright coloration could lure insect prey to the web vicinity, increasing the spider's foraging success. Alternatively, the markings could function as disruptive camouflage, making it difficult for the insect prey to distinguish spiders from background colour variation. We measured the prey capture rates of wasp spiders, Argiope bruennichi, that were blacked out, shielded from view using a leaf fragment, or left naturally coloured. Naturally coloured spiders caught over twice the number of prey as did either blacked-out or leaf-shielded spiders, and almost three times as many orthopteran prey. Spectrophotometer measurements suggest that the bright yellow bands on the spider's abdomen are visible to insect prey, but not the banding on the legs, which could disguise the spider's outline. Thus, our results provide strong support for the hypothesis that bright coloration in the wasp spider acts as a visual lure for insect prey and weak support for the hypothesis that the arrangement of the banding pattern across the spider's body disguises the presence of the spider on the web. PMID:18331982

  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. 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. PMID:26820263

  15. Financial Planners: Educating Widows in Personal Financial Planning

    Science.gov (United States)

    Korb, Brian R.

    2010-01-01

    Widows constitute a growing segment of the U.S. population; however, very little has been done to educate them on the basics of personal financial planning. The creation and implementation of financial planning education programs for widows can help them become more financially literate and free them from anxiety and fear. Interviews with eight…

  16. Young widows, tragic voices. Voices of girls 2: Africa.

    Science.gov (United States)

    Owen, M

    1998-01-01

    The tragic consequences for young girls of becoming widows or being the daughters of widows have not yet been addressed. In Africa, girls are sometimes given in marriage to old men. When the girls are widowed while still young, their chances for remarriage are slim. The marriages of girl children continue unabated in Africa and may be on the increase because of the AIDS epidemic. Modern legislation that complies with marriage age obligations created by the Convention for the Elimination of Discrimination Against Women simply creates statutory limits to marriage without parental consent and fails to regulate child marriages arranged by parents. Being the daughter of a widow is almost as bad as being a widow, because widows routinely withdraw their daughters from school to protect them from unwanted sexual approaches or marrying them off at a young age. Widows and their daughters are often considered chattel by male relatives who feel no compulsion to seek their consent before arranging marriages for them. Child widowhood is not addressed in the Platform for Action of the Fourth World Conference on Women, but during the 1998 UN Commission on the Status of Women, the European Union countries agreed to pay special attention to widows. It is time for international agencies to begin to collect data on this issue. PMID:12321766

  17. Recent Widows' Kin Support and Orientations to Self-Sufficiency.

    Science.gov (United States)

    O'Bryant, Shirley L.; Morgan, Leslie A.

    1990-01-01

    Data on recently widowed women suggest that many are quite self-sufficient; however, in areas where support is needed, they largely rely on children. Widows' past experiences and attitudes toward independence influenced amount of overall help they received, whereas income, number of children, and perceived willingness of children to help affected…

  18. Poverty among widows of Kinshasa, Congo.

    Science.gov (United States)

    D'Souza, S

    2000-09-01

    The linkages between poverty and death in the family in a sector of the city of Kinshasa, capital of the Democratic Republic of Congo (previously Zaire) were studied. The poor people have been identified using 3 convergent norms, described in the Methods of Materials section, based on total expenditure, calorie consumption in food, and proportion of expenditure for food. Family histories were recorded to understand the difficult situation of widow-headed households identified within the sample area. The relationship between death in the family and poverty was bi-directional: on the one hand, death of the breadwinner can accelerate the level of poverty; and on the other, poverty conditions can result in further deaths in the family. PMID:11057062

  19. 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.

  20. Older widows' experience of living alone at home.

    Science.gov (United States)

    Porter, E J

    1994-01-01

    Older widows' experience of living alone is described in this research. Based on Husserl's (1913/1962) philosophy, a phenomenological method was used. Prior to data-gathering, knowledge pertaining to older widows' experience was bracketed. During semi-structured, tape-recorded conversations, seven older widows described how they lived at home alone. From data pertaining to their actions, intentions and perceptions, four phenomena of the lived experience were developed: (a) making aloneness acceptable; (b) going my own way; (c) reducing my risks; and (d) sustaining myself. PMID:8200675

  1. Violence Against Scheduled Caste Widows: A Theoretical Study

    Directory of Open Access Journals (Sweden)

    Batawal. Preeyadarshini Indira Shivakumar

    2013-07-01

    Full Text Available The life of the women whose husband dies while she is alive has been institutionally made miserable by the norms of patriarchy. She faces emotional trauma, familial exploitation and social stigma. She has to adjust with in-laws, find some job for supporting her young children, adjust with sons and daughters-in-law, and has to face the male gaze seductive overtones and even molestation attempts. If the widows belong to the scheduled caste, then her life become doubly miserable, as the society attempts to exploit and harass her. Many of the incidents and statistics discussed in the paper described the violence against the scheduled caste widows. It is suggested to form strict legislations for the violence against the scheduled caste widows in particular and widows in general.

  2. Regulation of wolf spider populations

    OpenAIRE

    Rickers, Silke

    2005-01-01

    Aim of this study was to identify major regulatory mechanisms for wolf spider populations. Field and laboratory experiments focussed on the importance of prey availability (autochthonous & allochthonous), food quality and habitat heterogeneity on performance of individual wolf spiders or whole populations and on intra- (cannibalism) and interspecific (intraguild predation) relationships in wolf spiders. Wolf spider populations on xeric grasslands near Darmstadt (Germany) are increased on graz...

  3. 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.

  4. 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.

  5. Spider Bites (For Parents)

    Science.gov (United States)

    ... brown recluse spider bite: red blister in the center with surrounding bluish discoloration around the bite swelling or redness around the bite development of pain around the bite within 2 to 8 hours joint stiffness or pain nausea, vomiting body rash fever and ...

  6. Spiders in a hostile world (Arachnoidea, Araneae)

    OpenAIRE

    Helsdingen, Peter J. van

    2012-01-01

    Spiders are powerful predators, but the threats confronting them are numerous. A survey is presented of the many different arthropods which waylay spiders in various ways. Some food-specialists among spiders feed exclusively on spiders. Kleptoparasites are found among spiders as well as among Mecoptera, Diptera, Lepidoptera, and Heteroptera. Predators are found within spiders’ own population (cannibalism), among other spider species (araneophagy), and among different species of Heteroptera, O...

  7. 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.

  8. Visual odometry in the wolf spider Lycosa tarantula (Araneae: Lycosidae).

    Science.gov (United States)

    Ortega-Escobar, J; Ruiz, M A

    2014-02-01

    The wolf spider Lycosa tarantula homes using path integration. The angular component of the displacement is measured using a polarized-light compass associated with the functioning of the anterior median eyes. However, how L. tarantula estimates the linear component of the displacement was not known prior to this investigation. The ability of L. tarantula to gauge the distance walked after being displaced from its burrow was investigated using experimental channels placed in an indoor setup. Firstly, we manipulated the perception of visual stimuli by covering all the spider's eyes. Secondly, we changed the optic flow supplied by a black-and-white grating (λ=2 cm) perceived either in the lateral or in the ventral field of view. Finally, the period of the lateral or ventral grating was changed from λ=2 cm to λ=1 cm. Our results indicate that visual information contributes to distance estimation because when the spider's eyes were covered, the spiders tended to search for the burrow at very variable distances. This visual information is created by the motion of the image as the spider walks, the motion in the lateral field of view being the most important. The preference of a lateral optic flow over the ventral flow can be explained by the difference in the resolution capacity of the posterior lateral eyes and the anterior lateral eyes. PMID:24477612

  9. Economic analysis of spider web airline networks

    Institute of Scientific and Technical Information of China (English)

    Wen-dong Yang; Jin-fu Zhu; Qiang Gao; Wen-fang Wang

    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.

  10. Spiders' Size Exagerrated in Minds of Those Who Fear Them

    Science.gov (United States)

    ... was then shown pictures of spiders, birds and butterflies. Unsurprisingly, both groups said the spider pictures were ... the size of the spiders compared to the butterflies. The participants' estimation of spider size was affected ...

  11. 42 CFR 435.137 - Disabled widows and widowers who would be eligible for SSI except for the increase in disability...

    Science.gov (United States)

    2010-10-01

    ... for SSI except for the increase in disability benefits resulting from elimination of the reduction... widows and widowers who would be eligible for SSI except for the increase in disability benefits... to aged, blind, or disabled individuals receiving SSI or State supplements, the agency much...

  12. Widow Inheritance and HIV Prevalence in Bondo District, Kenya: Baseline Results from a Prospective Cohort Study

    OpenAIRE

    Agot, Kawango E; Vander Stoep, Ann; Tracy, Melissa; Obare, Billy A.; Bukusi, Elizabeth A.; Ndinya-Achola, Jeckoniah O; Moses, Stephen; Weiss, Noel S.

    2010-01-01

    Background Widow Inheritance is a widespread cultural practice in sub-Saharan Africa that has been postulated as contributing to risk of HIV transmission. We present baseline results from a study designed to investigate the association between widow inheritance and HIV acquisition. Methods and Findings We performed a cross-sectional analysis of baseline data from a prospective cohort study to investigate if widow inheritance is a risk practice for HIV infection. Study participants were 1,987 ...

  13. Violence Against Scheduled Caste Widows: A Theoretical Study

    OpenAIRE

    2013-01-01

    The life of the women whose husband dies while she is alive has been institutionally made miserable by the norms of patriarchy. She faces emotional trauma, familial exploitation and social stigma. She has to adjust with in-laws, find some job for supporting her young children, adjust with sons and daughters-in-law, and has to face the male gaze seductive overtones and even molestation attempts. If the widows belong to the scheduled caste, then her life become doubly miserable, as the society ...

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

    Science.gov (United States)

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

  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. Violence Against Widows in Nepal: Experiences, Coping Behaviors, and Barriers in Seeking Help.

    Science.gov (United States)

    Sabri, Bushra; Sabarwal, Shrutika; Decker, Michele R; Shrestha, Abina; Sharma, Kunda; Thapa, Lily; Surkan, Pamela J

    2016-05-01

    Widows are a vulnerable population in Nepal. This study examined Nepalese widows' experiences of violence, their coping strategies, and barriers faced in seeking help. Study participants were recruited from Women for Human Rights, an NGO in Nepal. A stratified purposive sampling approach was used to select 51 widows and 5 staff members for in-depth interviews. Twenty-seven women who experienced violence were included in this analysis. Data were analyzed and synthesized using a thematic analysis procedure. Widows reported a range of violent experiences perpetrated by family and community members that spanned psychological, physical, and sexual abuse. Women dealt with abusive experiences using both adaptive (e.g., attempting to move ahead, seeking social support, using verbal confrontation) and maladaptive coping strategies (e.g., suicidal thoughts or self-medication). However, they faced barriers to seeking help such as insensitivity of the police, perceived discrimination, and general lack of awareness of widows' problems and needs. Findings highlight the need for interventions across the individual, family, community, and policy levels. Avenues for intervention include creating awareness about widows' issues and addressing cultural beliefs affecting widows' lives. Furthermore, efforts should focus on empowering widows, promoting healthy coping, and addressing their individual needs. PMID:25657102

  17. 38 CFR 10.37 - Claim of widow not living with veteran at time of veteran's death.

    Science.gov (United States)

    2010-07-01

    ... by the widow involving desertion or moral turpitude will be construed as the willful act of the widow. Cause of separation and time and duration of separation at the time of the death of the veteran shall...

  18. Debt, shame, and survival: becoming and living as widows in rural Kerala, India

    Directory of Open Access Journals (Sweden)

    Mohindra Katia

    2012-11-01

    Full Text Available Abstract Background The health and well-being of widows in India is an important but neglected issue of public health and women’s rights. We investigate the lives of Indian women as they become widows, focussing on the causes of their husband’s mortality and the ensuing consequences of these causes on their own lives and identify the opportunities and challenges that widows face in living healthy and fulfilling lives. Methods Data were collected in a Gram Panchayat (lowest level territorial decentralised unit in the south Indian state of Kerala. Interviews were undertaken with key informants in order to gain an understanding of local constructions of ‘widowhood’ and the welfare and social opportunities for widows. Then we conducted semi-structured interviews with widows in the community on issues related to health and vulnerability, enabling us to hear perspectives from widows. Data were analysed for thematic content and emerging patterns. We synthesized our findings with theoretical understandings of vulnerability and Amartya Sen’s entitlements theory to develop a conceptual framework. Results Two salient findings of the study are: first, becoming a widow can be viewed as a type of ‘shock’ that operates similarly to other ‘economic shocks’ or ‘health shocks’ in poor countries except that the burden falls disproportionately on women. Second, widowhood is not a static phenomenon, but rather can be viewed as a multi-phased process with different public health implications at each stage. Conclusion More research on widows in India and other countries will help to both elucidate the challenges faced by widows and encourage potential solutions. The framework developed in this paper could be used to guide future research on widows.

  19. Structural characterization of a variety of spider silks from Turkey using different biophysical techniques

    OpenAIRE

    İDE, Semra; Bayarı, Sevgi Haman; TÜRKEŞ, Tuncay; Mergen, Y. Orhan; Çelik, Ömer; Bütün, Vural; Sargon, Mustafa F; Kocatepe, Neslihan; Kriechbaum, Manfred

    2011-01-01

    Various experimental methods (XRD, FTIR, SAXS, DLS and SEM) were used to investigate structures of the silk samples weaved by spiders in Turkey. Silk samples were collected from the natural habitats belonging to the spider species (i.e., Near Salt Lake/şereflikoçhisar, İvriz Dam/Ereǧli-Konya, Karataş Lake/Burdur and several locations in Black Sea Region of Turkey). Among all collected species, Araneidae (Araneus angulatus, Argiope bruennichi, Argiope lobata, Larinoides cornutus), Eresidae (Er...

  20. 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…

  1. Spider-Web Inspired Mechanical Metamaterials

    OpenAIRE

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

    2016-01-01

    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 novel design for mechanical metamaterials based on its periodic repetition. We demonstrate that spider-web metamaterial structure plays an important role in th...

  2. Spider-Venom Peptides as Therapeutics

    OpenAIRE

    Glenn F King; Volker Herzig; Rash, Lachlan D; Jensen, Jonas E.; Sing Yan Er; Sebastian Senff; Saez, Natalie J.

    2010-01-01

    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 ...

  3. Intelligent spider for Internet searching

    OpenAIRE

    Chung, YM; Ramsey, M; Yang, CC; Ma, PC; Yen, JCH; H Chen

    1997-01-01

    As World Wide Web (WWW) based Internet services become more popular, information overload also becomes a pressing research problem. Difficulties with searching on the Internet get worse as the amount of information that is available increases. A scalable approach to support Internet search is critical to the success of Internet services and other current or future national information infrastructure (NII) applications. A new approach to build an intelligent personal spider (agent), which is b...

  4. INSIDE AND OUTSIDE STORY OF POST FEMINISM IN MARTIN AMIS?S THE PREGNANT WIDOW

    OpenAIRE

    SAMBHUNATH MAJI

    2012-01-01

    Eroticism has a wider definition. Martin Amis is the most successful postmodern British fiction writer in defining this. The Pregnant Widow is a demi-bible of polished eroticism. Every psalm of this bible beats post feministic pulse. This small excerpt will be an endeavour to conceptualize post feminism and how it is defined by Amis in his novel The Pregnant Widow. Feminism is often defined as a movement and revolution for the liberation of women. This research paper will focu...

  5. Spider management in agroecosystems: Habitat manipulation

    Science.gov (United States)

    Mansour, Fadel; Richman, David B.; Whitcomb, W. H.

    1983-01-01

    Based on the literature and on work conducted in Israel, the management of spider populations through habitat manipulation was found to be very helpful in controlling pest insects in various crops. Spiders were found to be reduced or eliminated by non-selective insecticides, although some resistance has been noted

  6. Tangled in a sparse spider web

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  7. 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…

  8. Stigma of tiger attack: Study of tiger-widows from Sundarban Delta, India*

    Science.gov (United States)

    Chowdhury, Arabinda N.; Brahma, Arabinda; Mondal, Ranajit; Biswas, Mrinal K.

    2016-01-01

    Aims: Human-tiger conflict (HTC) is a serious public health issue in Sundarban Reserve Forest, India. HTC is a continued concern for significant mortality and morbidity of both human and tiger population. This study examined 49 widows, whose husbands were killed by tigers, in order to explore the cultural stigma related with tiger-killing and consequent discrimination and social rejection. Different psychosocial aspects of community stigma associated with tiger-killings is discussed in the context of local culture. Methods: A mix of both quantitative and qualitative methods was used in this ethnographic study in two mouzas of Sundarban adjacent to Reserve Forest, involving (1) Village Survey for Tiger-widows, (2) In-depth interview of the widows, (3) Focus Group discussions, (4) Participatory mapping and (5) Stigma assessment by using a 28 item stigma scale especially devised for this research. For comparison of stigma-burden snake-bite widows and normal widows were taken from the same community. Results: Tiger-widows showed significantly higher stigma scores on all the clusters (fear, negative feelings, disclosure, discrimination, community attitudes, and spiritual dimension) than from both normal and snake-bite widows. They also showed higher total stigma score (65.9 ± 9.8) than normal widows (35.8 ± 8.0) and snake-bite widows (40.1 ± 7.1) and this difference was highly significant (P < 0.001). IDIs and FGDs helped to unfold the cultural construct of stigma related to tiger-killing. This can be seen in how the tiger-widows’ quality of life has been negatively impacted with a multitude of post-trauma psychological scars, deprivation, abuse and exploitation. Conclusions: The study proposes that administrative strategy for sustainable alternative income generation and conservation policy with integrated participatory forest management may save both human and tiger. A community ecocultural mental health programme addressing to eradicate the cultural stigma

  9. Ferromagnetic behaviour of anthropogenic multi-walled carbon nanotubes trapped in spider web indoor.

    Science.gov (United States)

    Sonkar, Sumit Kumar; Tripathi, Kumud Malika; Sarkar, Sabyasachi

    2014-03-01

    Black carbon (BC) (as partly burnt black particulate matter) present indoor are deposited on interior surfaces of the indoors (easily visualize over the blades of electric fan/exhausts and over domestic spider webs) are known to be a potential indoor pollution problem. We detect with the help of indoor spider webs the floating BC contains a significant amount of defective multiwalled carbon nanotubes (MWCNTs) possessing room temperature ferromagnetism. Microscopic studies shows a lot of internal and surfacial defects in these indoor-MWCNTs. Electron paramagnetic resonance (EPR) showed the presence of very stable carbon centred radicals in these indoor-MWCNTs. Room temperature ferromagnetism most importantly originated by the presence of a large amount of unpaired spin frustrated carbon centred radicals (trapped in defects, junctions and fractures) which are inadvertently formed during the pyrolysis of carbonaceous materials through routine domestic activities. PMID:24745259

  10. Wilson, Spider oral history interview

    OpenAIRE

    Interviewee: Wilson, Spider; Interviewer: Walliser, Andrea; Interviewer: La, Michelle; Principal Investigator: Hall, Peter V

    2013-01-01

    Spider Wilson is a tattoo artist who operated a tattoo parlour on Columbia Street for 17 years, and is a New Westminster native. He was born at St. Mary’s Hospital and attended John Robson Elementary and later Lord Kelvin Elementary. He believes his job as a tattoo artist is a mixture of being a social worker and a bartender. He reports feeling a strong connection to the business community on Columbia Street. Having grown up five minutes away from his current shop, he talks about the changes ...

  11. Cultural care of older Greek Canadian widows within Leininger's theory of culture care.

    Science.gov (United States)

    Rosenbaum, J N

    1990-01-01

    Cultural care themes were abstracted from a large scale study of older Greek Canadian widows conceptualized within Leininger's theory of Cultural Care Diversity and Universality. Ethnonursing, ethnographic, and life health-care history methods were used. Data were collected using observation-participation and interviews in three Greek Canadian communities with 12 widowed key informants and 30 general informants. Enabling tools used were interview inquiry guides, Leininger's Life History Health Care Protocol, Leininger's Acculturation Rating and Profile Scale of Traditional and Non-Traditional Lifeways, and field journal recordings. Data were analyzed using Leininger's phases of analysis for qualitative data. The two major cultural care themes which were abstracted from the raw data and patterns were: (1) Cultural care for Greek Canadian widows meant responsibility for, reciprocation, concern, love, companionship, family protection, hospitality, and helping, primarily derived from their kinship, religious, and cultural beliefs, and values, and (2) Cultural care continuity diminished the spousal care void and contributed to the health of Greek Canadian widows. These findings will stimulate future nursing research related to cultural care of diverse populations and guide nursing practice to provide culturally congruent care which will assist widows to reduce their spousal care void. The author thanks Dr. Madeleine Leininger, Dr. Judith Floyd, Dr. Marjorie Isenberg, and Dr. Bernice Kaplan for their guidance in completing the large scale study on which this article is based. PMID:2264941

  12. Levirate marriage amongst the Hebrews and widow's inheritance amongst the Yoruba: A comparative investigation

    Directory of Open Access Journals (Sweden)

    Samson O. Olanisebe

    2014-01-01

    Full Text Available In ancient Israel, even though widowhood was not something people were praying for, when it came, the people involved were protected by the legal and customary structures already in place. One of those structures in the Old Testament is the institution of the levirate marriage where the right and the possession due to a widow without a son for her late husband could be protected and appropriated. A similar custom was also found amongst the pre-colonial Yoruba people through the widow�s inheritance which guarantees the welfare of the widow after the demise of her husband. However, these structures have been dismantled by Christianity, thereby exposing the majority of present-day widows to untold hardship. This article, therefore, through historical, descriptive and comparative methods, examines the customs of the levirate marriage and widow�s inheritance in the two cultures, ascertains how effective they were in addressing the welfare and protection of the rights and privileges of widows and recommends how the church can better see to the welfare of the widows in the society.

  13. Simple Described the Soldiers Widows System of the Ming Dynasty

    Directory of Open Access Journals (Sweden)

    Song-mei ZHANG

    2006-09-01

    Full Text Available The soldiers widows of the Ming Dynasty haven’n been got special care and rarely inspected in history scholars. The paper will explore this issue on the basis of files information .It mainly including the inherited of descendants of the dead general and soldiers, the superior to young persons who were under the age of 14, and superior support to the mother, wife, daughter of the dead general and soldiers ,and the disabled, elderly persons themselves. On the basis of the establishment of former dynasty ,Ming has developed and promulgated the round military system, and enacted a national regulations, and have achieved good results. but also show obvious class and historical limitations, particularly that of late Ming Dynasty. Because the both internal and external,costly ,financial depletion, so the widows was at the stagnation and no application, intensified the Ming Dynasty's demise.
    Keywords: Ming Dynasty, soldiers, inherited, superior given, superior support
    Résumé Actuellement les recherches sur le système de soins particuliers accordés aux militaires invalides sont peu nombreux. A partir des documents et archives, cet essai étudie ce problème de la dynastie des Mings. Ce système comprend essentiellement l’héritage du poste des militaires décédés, les faveurs accordées à leur famille et leurs descendants ainsi que les soins donnés à des militaires invalides et de vieux militaires sans enfants. La dynastie des Mings a établi et perfectionné ce système, et a élaboré et promulgué des règlements concernés à l’échelle nationale. L’application de ce système a donné des fruits, mais il y a eu aussi des limites historique évidentes, en particulier depuis la dernière étape de la dynastie où les troubles intérieurs et l’invasion étrangère s’entremêlent, les dépenses étaient considérables, les finances étaient en difficulté, les mesures sur les soins particuliers paralysées sont devenues

  14. 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....... Game Theory Models F. By-Product Mutualism VI. Transitions in the Evolution of Sociality: Processes and Patterns A. From Premating to Postmating Dispersal B. From Outbreeding to Inbreeding C. From Maternal Care to Cooperative Breeding VII. Summary: From Subsocial to Inbred Social, an Overview...

  15. 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.

  16. 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

  17. [Diagnostic use of Internet: google the spider].

    Science.gov (United States)

    Soonawala, Darius; Brienen, Eric A T; Visser, Leo G

    2009-01-01

    A 23-year-old woman was working in a factory unpacking jars of Spanish olives when a spider bit her finger. She presented to the emergency outpatient department carrying the spider in a box. She was worried and wanted to know whether the spider, which may have originated from Spain, was poisonous. After a ten minute Internet search the spider was identified as Segestria florentina. It can inject neurotoxins causing temporary local numbness and pain. The patient was reassured and discharged without further treatment. Later, experts confirmed the species. Internet-based search engines can draw attention to unusual diagnoses which otherwise may easily be overlooked. A general search engine can also provide access to subjects that fall outside the scope of the more usual medical sources. PMID:19785819

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

    Science.gov (United States)

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

    2016-03-30

    Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid,Idmonarachne brasierigen. et sp. nov. from the Late Carboniferous (Stephanian,ca305-299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian-Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids andI. brasieri While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies. PMID:27030415

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

    Science.gov (United States)

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

    2016-01-01

    Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasieri gen. et sp. nov. from the Late Carboniferous (Stephanian, ca 305–299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian–Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri. While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies. PMID:27030415

  20. SPIDER ENVENOMING OF DOG - CASE REPORT

    OpenAIRE

    H. S. FERNANDES; M. SAKATE; A. L. Cherubini; A. F. PADOVANI; A.M.C. Meneses

    2002-01-01

    This report refers to a female Pinscher treated at the Veterinary Hospital of the Botucatu School of Veterinary Medicine and Animal Husbandry (FMVZ)-São Paulo State University (UNESP), Botucatu, 14 hours after a suspected spider envenoming. The animal showed spastic limbs, dyspnea, salivation, hypothermia, muscular fasciculation, non-responsive mydriasis, and claudication of the right hindlimb. The spider was later identified by the Center for the Study of Venoms and Venomous Animals-CEVAP/UN...

  1. 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.

  2. Rumination and avoidance as predictors of prolonged grief, depression, and posttraumatic stress in female widowed survivors of war

    NARCIS (Netherlands)

    N. Morina

    2011-01-01

    This study examined independent contributions of rumination and experiential avoidance in predicting symptoms of psychological distress among female widowed survivors of war. A decade after the war in Kosovo, 100 widowed survivors of war completed measures of rumination, experiential avoidance, depr

  3. 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…

  4. The Paradox of Cultural Self-Representation in Paule Marshall's "Praisesong for the Widow"

    Science.gov (United States)

    Ibironke, Olabode

    2004-01-01

    In this paper, I examine how Paule Marshall's "Praisesong For The Widow", fictionalizes "migrations of the subject". I argue that "Praisesong" explores the threshold between displacement, exile and prodigality. The paradox elaborated in this analysis is located precisely in how self-questioning ends up in self-affirmation; how conceptualisations…

  5. Effects of a Visiting Service for Older Widowed Individuals: A Randomized Clinical Trial

    Science.gov (United States)

    Onrust, Simone; Willemse, Godelief; Van Den Bout, Jan; Cuijpers, Pim

    2010-01-01

    The loss of the partner is an important risk factor for developing serious psychological problems. In this study the authors examined the effect of the visiting service on the mental health and quality of life of older widowed individuals. They conducted a pragmatic randomized trial. All respondents were randomly assigned to a visiting service (n…

  6. Fecundity increase supports adaptive radiation hypothesis in spider web evolution

    OpenAIRE

    Todd A. Blackledge; Coddington, Jonathan A.; Agnarsson, Ingi

    2009-01-01

    Identifying the mechanisms driving adaptive radiations is key to explaining the diversity of life. The extreme reliance of spiders upon silk for survival provides an exceptional system in which to link patterns of diversification to adaptive changes in silk use. Most of the world’s 41,000 species of spiders belong to two apical lineages of spiders that exhibit quite different silk ecologies, distinct from their ancestors. Orb spiders spin highly stereotyped webs that are suspended in air and ...

  7. Habitat productivity predicts the global distribution of social spiders

    OpenAIRE

    Majer, Marija; Svenning, Jens-Christian; Bilde, Trine

    2015-01-01

    Permanently-social spiders share a common suite of traits, including cooperative foraging and brood care, elimination of pre-mating dispersal, and the transition to an inbreeding mating system. Social spiders are confined to tropic and subtropical habitats, suggesting environmental constraints on the evolution of group living in spiders. Because, social spider groups are sedentary and dependent on arrival of insect prey in their capture webs, group living and the associated higher local densi...

  8. A case of spider phobia in a congenitally blind person.

    Science.gov (United States)

    Musial, Frauke; Kolassa, Iris-Tatjana; Sülzenbrück, Sandra; Miltner, Wolfgang H R

    2007-09-30

    Vision is the key sensory system in humans, leading to the implicit assumption that the acquisition of spider phobia is predominantly mediated through the visual pathway. We report on a congenitally blind person with spider phobia, showing that the acquisition of spider phobia does not necessarily depend on visual cues. PMID:17597227

  9. SPIDER: Next Generation Chip Scale Imaging Sensor

    Science.gov (United States)

    Duncan, Alan; Kendrick, Rick; Thurman, Sam; Wuchenich, Danielle; Scott, Ryan P.; Yoo, S. J. B.; Su, Tiehui; Yu, Runxiang; Ogden, Chad; Proiett, Roberto

    The LM Advanced Technology Center and UC Davis are developing an Electro-Optical (EO) imaging sensor called SPIDER (Segmented Planar Imaging Detector for Electro-optical Reconnaissance) that provides a 10x to 100x size, weight, and power (SWaP) reduction alternative to the traditional bulky optical telescope and focal plane detector array. The substantial reductions in SWaP would reduce cost and/or provide higher resolution by enabling a larger aperture imager in a constrained volume. The SPIDER concept consists of thousands of direct detection white-light interferometers densely packed onto Photonic Integrated Circuits (PICs) to measure the amplitude and phase of the visibility function at spatial frequencies that span the full synthetic aperture. In other words, SPIDER would sample the object being imaged in the Fourier domain (i.e., spatial frequency domain), and then digitally reconstruct an image. The conventional approach for imaging interferometers requires complex mechanical delay lines to form the interference fringes. This results in designs that are not traceable to more than a few simultaneous spatial frequency measurements. SPIDER seeks to achieve this traceability by employing micron-=scale optical waveguides and nanophotonic structures fabricated on a PIC with micron-scale packing density to form the necessary interferometers. Prior LM IRAD and DARPA/NASA CRAD-funded SPIDER risk reduction experiments, design trades, and simulations have matured the SPIDER imager concept to a TRL 3 level. Current funding under the DARPA SPIDER Zoom program is maturing the underlying PIC technology for SPIDER to the TRL 4 level. This is done by developing and fabricating a second-generation PIC that is fully traceable to the multiple layers and low-power phase modulators required for higher-dimension waveguide arrays that are needed for higher field-of-view sensors. Our project also seeks to extend the SPIDER concept to add a zoom capability that would provide

  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. 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. PMID:23321095

  12. 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. PMID:24940885

  13. 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.

  14. Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

    International Nuclear Information System (INIS)

    Stable nitrogen isotopic composition (δ15N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ15N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ15N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: → δ15N of aquatic insects increases downstream with anthropogenic nitrogen inputs. → δ15N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. → The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

  15. The path to the nest of spiders The path to the nest of spiders

    Directory of Open Access Journals (Sweden)

    Eliane Luz Bayer

    2008-04-01

    Full Text Available Italo Calvino writes in his preface to The Path to the Nest of Spiders that the novel answers to the "ripeness of the time" since ht wrote it after wartime, a period when everyone had a tale to tell. He tells us that this is a story in which iobody is a hero and nobody has the class consciousness necessary to unify them in the struggle. Calvino acknowledges that it was difficult to conciliate his experiences with the postwar literary movement which he calls Neo-expresSionism, a term which, he thinks, describes better Italian Neo-realism. This is a book with a full realistic depictior of the incongruousness of the whole situation, showing rumen beings driven by loneliness, aggressiveness, unfulfilment and failure to meet, their nerves frayed by the War. It reveals human beings in their weaknesses, subjected to deterministic fates changing roles according to circumstance. Partisans shift to the Nazi side and inform on their f rmer allies and vice-versa, being later chased in revenge. The novel has as its setting Italy under Fascism and unde German occupation, the Italian people being divided betw en the fascists of the "Black Brigade" and the "Partisa4s" who belonged to the Resistance. Although this is a pOlitical book, it has universal appeal. At the same time that it livens up historical facts about the period, it moves our feelings. Calvino's book is about World War II as it is viewed and felt by a small outcast, Pin, who makes considerable efforts to be accepted and understood by adults. In his daily life Pinsuffers the consequences Of the war. His aggressive disposition reflects the environment which he has been brought up in: since he was born, his country has been at war. Besides that, his only sister is a whore, whom he hates and despises. Italo Calvino writes in his preface to The Path to the Nest of Spiders that the novel answers to the "ripeness of the time" since ht wrote it after wartime, a period when everyone had a tale to tell

  16. 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...

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

    Directory of Open Access Journals (Sweden)

    F. Perveen

    2012-03-01

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

  18. 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.

  19. 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

  20. A dynamic analysis of the effect of social security reform on Spanish widow pensioners

    Directory of Open Access Journals (Sweden)

    Peinado Patricia

    2011-01-01

    Full Text Available This paper shows the dynamic effects of the reform of the Spanish social security pension system on the pensions received by one of the most vulnerable groups of the population, namely, widows. We undertake a duration analysis to account for the effects of reform over time. We study the effects on the widows’ overall financial welfare in terms of the evolution of their risk of poverty. We show that the combined effects of the measures to be implemented will have a positive impact; that is to say, the risk of poverty diminishes with respect to the current financial situation of the widows. However, the risk of poverty increases as the pensioners get older.

  1. INSIDE AND OUTSIDE STORY OF POST FEMINISM IN MARTIN AMIS?S THE PREGNANT WIDOW

    Directory of Open Access Journals (Sweden)

    SAMBHUNATH MAJI

    2012-11-01

    Full Text Available Eroticism has a wider definition. Martin Amis is the most successful postmodern British fiction writer in defining this. The Pregnant Widow is a demi-bible of polished eroticism. Every psalm of this bible beats post feministic pulse. This small excerpt will be an endeavour to conceptualize post feminism and how it is defined by Amis in his novel The Pregnant Widow. Feminism is often defined as a movement and revolution for the liberation of women. This research paper will focus how feminism came as promise and how they are left untouched. My curiosity equally runs high if this same frustration continues even in the case of post feminism also. Is Amis uniquely unparallel in sharpshooting this?

  2. Cost-utility of a visiting service for older widowed individuals: Randomised trial

    Directory of Open Access Journals (Sweden)

    Willemse Godelief

    2008-06-01

    Full Text Available Abstract Background Despite a growing understanding of the effectiveness of bereavement interventions and the groups that benefit most from them, we know little about the cost-effectiveness of bereavement interventions. Methods We conducted a cost-utility analysis alongside a randomized clinical trial on a visiting service for older widowed individuals (n = 110 versus care as usual (CAU; n = 106. The visiting service is a selective bereavement intervention that offers social support to lonely widows and widowers by a trained volunteer. Participants were contacted 6–9 months post-loss. Eleven percent of all contacted persons responded and eight percent participated in the trial. The primary outcome measure was quality adjusted life years (QALYs gained (assessed with the EQ-5D, which is a generic measure of health status. Costs were calculated from a societal perspective excluding costs arising from productivity losses. Using the bootstrap method, we obtained the incremental cost utility ratio (ICUR, projected these on a cost-utility plane and presented as an acceptability curve. Results Overall, the experimental group demonstrated slightly better results against slightly higher costs. Whether the visiting service is acceptable depends on the willingness to pay: at a willingness to pay equal to zero per QALY gained, the visiting service has a probability of 31% of being acceptable; beyond €20,000, the visiting service has a probability of 70% of being more acceptable than CAU. Conclusion Selective bereavement interventions like the visiting service will not produce large benefits from the health economic point of view, when targeted towards the entire population of all widowed individuals. We recommend that in depth analyses are conducted to identify who benefits most from this kind of interventions, and in what subgroups the incremental cost-utility is best. In the future bereavement interventions are then best directed to these groups. Trial

  3. Morbidity Patterns and Health Care Seeking Behavior among Older Widows in India

    OpenAIRE

    Agrawal, Gopal; Keshri, Kunal

    2014-01-01

    In the process of health transition, India is facing rapid pace of demographic aging. Rapid increase in older adult population posed serious concerns regarding health and health care utilization for them. However, very limited research documented resultant implications of demographic aging for health and health care use in the nexus of marital status and gender. With this perspective, the present study examined patterns in morbidity prevalence and health seeking behaviour among older widows i...

  4. Health transitions in recently widowed older women: a mixed methods study

    OpenAIRE

    DiGiacomo, Michelle; Lewis, Joanne; Nolan, Marie T.; Phillips, Jane; Davidson, Patricia M

    2013-01-01

    Background Older recently widowed women are faced with increased health risks and chronic conditions associated not only with bereavement, but also, older age. Loss and grief, adjusting to living alone, decreased income, and managing multiple chronic conditions can impact on older women’s ability to transition following recent spousal bereavement. Providing appropriate, timely, and effective services to foster this life transition is of critical importance, yet few services directed towards t...

  5. ‘He wasn’t in that chair’: what loneliness means to widowed older people

    Directory of Open Access Journals (Sweden)

    Kate Mary Bennet

    2012-06-01

    Full Text Available We have little robust empirical evidence that articulates what being lonely means to older people and even less knowledge about what loneliness means to older widows and widowers; this article addresses that deficit. We undertook a re-analysis of 125 interviews with older people (aged 55-98 that explored their experiences of widowhood. In this article, we focus on those interviews in which participants described themselves as experiencing loneliness by the spontaneous use of terms such as ‘‘lonely’’, ‘‘loneliness’’ or ‘‘lonesome’’. Almost half of the participants (42% described themselves in that way without any prompting from the interviewer. In terms of understanding and describing the meaning of loneliness, 50% explained loneliness in terms of absence of either their spouse, a physical presence in the house or people. One-third (34% discussed loneliness in relation to time and place: night, weekends and home, and 4% described the emotional impact of loneliness. Fifteen per cent just said they were lonely without elaboration, assuming a common understanding of what loneliness means. Our findings suggest that widowed people’s understanding and experience of loneliness resonates with the concept of ‘‘emotional’’ loneliness, resulting from the loss of significant social and emotional attachment. This has important implications for the types of interventions that may be appropriate for remediating loneliness in this group.

  6. Spiders (Araneae. Chapter 7.3

    Directory of Open Access Journals (Sweden)

    Wolfgang Nentwig

    2010-07-01

    Full Text Available A total of 47 spider species are alien to Europe; this corresponds to 1.3 % of the native spider fauna. They belong to (in order of decreasing abundance Theridiidae (10 species, Pholcidae (7 species, Sparassidae, Salticidae, Linyphiidae, Oonopidae (4-5 species each and 11 further families. There is a remarkable increase of new records in the last years and the arrival of one new species for Europe per year has been predicted for the next decades. One third of alien spiders have an Asian origin, one fifth comes from North America and Africa each. 45 % of species may originate from temperate habitats and 55 % from tropical habitats. In the past banana or other fruit shipments were an important pathway of introduction; today potted plants and probably container shipments in general are more important. Most alien spiders established in and around human buildings, only few species established in natural sites. No environmental impact of alien species is known so far, but some alien species are theoretically dangerous to humans.

  7. SPIDER: A decade of measuring ultrashort pulses

    International Nuclear Information System (INIS)

    It was ten years ago in Rochester, New York that the first SPIDER was built. This simple acronym belies the subtleties of its inner workings; Spectral Phase Interferometry for Direct Electric-field Reconstruction (the ''f'' in field conveniently missed the cut) is a device that measures ultrashort pulses, utilizing spectral shearing interferometry and directly recovering the spectral phase. The very first SPIDER apparatus occupied nearly half an optical table, used a scanning monochromator, and had no computerized inversion routine. In the intervening decade, SPIDER has grown up. It has found a strong foothold in ultrafast laboratories throughout the world. Multiple groups have found useful new applications with this vital measurement tool, while others have contributed to the improvement of SPIDER itself, reaching to ever shorter pulses, new wavelength regimes, and making devices more sensitive, robust, smaller and faster. It also adapts to a field of research that changes rapidly. It was first designed to track and quantify the remaining spectral phase in a pulse to perfect its compression. In ten years, with the advent of pulse shapers, the real benefits of field diagnostics are becoming apparent. We have shifted away from the race towards the shortest IR pulse to a wide use of complex shaped pulses in almost every spectral range from far IR to XUV. But the quest of the shortest pulse is not over and new compression techniques utilize really broad spectra that are highly structured. All these applications provide new challenges for characterization techniques

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

    OpenAIRE

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

    2010-01-01

    Abstract 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 paramet...

  9. Electrophysiological correlates of threat processing in spider phobics

    OpenAIRE

    Kolassa, Iris-Tatjana; Musial, Frauke; Mohr, Alexander; Trippe, Ralf H.; Miltner, Wolfgang H. R.

    2005-01-01

    The electrocortical correlates of the processing of feared/fear-relevant and neutral stimuli were investigated in a pictorial emotional Stroop paradigm with spider phobic, social phobic, and nonphobic subjects. Subjects identified either the color of red or blue pictures of spiders, birds, or flowers (emotional Stroop task) or the object itself (identification task) by pressing different buttons. No emotional Stroop interference was found for spider phobic subjects when identifying the color ...

  10. Elasto-capillary windlass : from spider silk to smart actuators

    OpenAIRE

    Elettro, Hervé

    2015-01-01

    This PhD work aimed to understand and recreate artificially a self-assembling mechanism involving capillarity and elasticity present in spider silk. The primary function of the micronic glue droplets that exist on spider capture silk is to provide the spider web with adhesive properties. These droplets play yet another role: the dramatic enhancement of silk mechanical properties, as well as the preservation of the integrity of the web structure. The localization of the buckling instability wi...

  11. Rates of trauma spectrum disorders and risks of posttraumatic stress disorder in a sample of orphaned and widowed genocide survivors

    Directory of Open Access Journals (Sweden)

    Susanne Schaal

    2011-06-01

    Full Text Available During the Rwandan genocide of 1994, nearly one million people were killed within a period of 3 months.The objectives of this study were to investigate the levels of trauma exposure and the rates of mental health disorders and to describe risk factors of posttraumatic stress reactions in Rwandan widows and orphans who had been exposed to the genocide.Trained local psychologists interviewed orphans (n=206 and widows (n=194. We used the PSS-I to assess posttraumatic stress disorder (PTSD, the Hopkins Symptom Checklist to assess depression and anxiety symptoms, and the M.I.N.I. to assess risk of suicidality.Subjects reported having been exposed to a high number of different types of traumatic events with a mean of 11 for both groups. Widows displayed more severe mental health problems than orphans: 41% of the widows (compared to 29% of the orphans met symptom criteria for PTSD and a substantial proportion of widows suffered from clinically significant depression (48% versus 34% and anxiety symptoms (59% versus 42% even 13 years after the genocide. Over one-third of respondents of both groups were classified as suicidal (38% versus 39%. Regression analysis indicated that PTSD severity was predicted mainly by cumulative exposure to traumatic stressors and by poor physical health status. In contrast, the importance given to religious/spiritual beliefs and economic variables did not correlate with symptoms of PTSD.While a significant portion of widows and orphans continues to display severe posttraumatic stress reactions, widows seem to constitute a particularly vulnerable survivor group. Our results point to the chronicity of mental health problems in this population and show that PTSD may endure over time if not addressed by clinical intervention. Possible implications of poor mental health and the need for psychological intervention are discussed.

  12. The Language of Revolution and the Power of Storytelling in The Pregnant Widow

    OpenAIRE

    Alaa Alghamdi

    2014-01-01

    Martin Amis uses the language of revolution to describe the newly altered social circumstances at the height of the sexual revolution in his semi-autobiographical novel The Pregnant Widow. The concept of a ‘language of revolution’ as well as second- and third-wave feminist scholarship is applied to a textual analysis of the novel. Amis’s brand of satire creates a sense of displacement and challenges existing perceptions about gender, culture and sexuality, exposing them as constructed and cha...

  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

    Selection by inbreeding depression should favour mating biases that reduce the risk of fertilization by related mates. However, equivocal evidence for inbreeding avoidance questions the strength of inbreeding depression as a selective force in the evolution of mating biases. Lack of inbreeding...... 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...

  14. Ecopsychosocial Aspects of Human–Tiger Conflict: An Ethnographic Study of Tiger Widows of Sundarban Delta, India

    Science.gov (United States)

    Chowdhury, Arabinda N.; Mondal, Ranajit; Brahma, Arabinda; Biswas, Mrinal K.

    2016-01-01

    AIMS Human–tiger conflict (HTC) is a serious public health issue in Sundarban Reserve Forest, India. HTC is a continued concern for the significant mortality and morbidity of both human and tiger population. This is the first comprehensive report on Sundarban tiger–human conflicts and its impact on widows whose husbands were killed by tigers. The study attempts to explore the situation analysis of HTC and the aftermath of the incident including bereavement and coping, the cultural stigma related to being killed by a tiger and the consequent discrimination, deprivation, and social rejection, and the impact on the mental health of the tiger-widows. METHODS This is a three-phase ethnographic research with a mix of quantitative and qualitative methods. In the first phase, a door-to-door village survey (3,084 households) was carried out in two villages of Sundarban, which are adjacent to the Reserve Forest, in which the incidents of human–animal conflicts and the 65 tiger-widows identified were documented. In the second phase, the 65 tiger-widows were studied to explore the ecodemography of tiger attacks and tiger-widows alongside the stigma issue by using a stigma questionnaire (n = 49). The stigma burden was compared with normal widows (n = 21) and snake-bite widows (n = 18). In the third phase, the psychosocial and cultural dimensions related to tiger attacks were studied by using in-depth interviews (IDI) of the tiger-widows, focus-group discussions (FGD), and participatory mapping in the community. Clinical examinations of the mental health of the widows were also carried out in this phase. RESULTS The mean age of the 65 widows was 43.49 ± 9.58 years. Of this, 12.3% of the widows had remarried and only 4.6% of the widows were literate. In all, 67.2% of all tiger attacks occurred as a result of illegal forest entry. The main livelihood of the former husbands of the widows were 43.8% wood cutting, 28.1% fishing, 10.9% crab catching, 9.4% tiger prawn seed

  15. Recombinant DNA production of spider silk proteins

    OpenAIRE

    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...

  16. 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.

  17. [Poisoning by spiders of Loxosceles genus].

    Science.gov (United States)

    De Roodt, Adolfo R; Salomón, Oscar D; Lloveras, Susana C; Orduna, Tomás A

    2002-01-01

    Despite the great number of spiders in the world, only a small group of them is capable of producing death in humans. In Argentina, there are only three of the four genera of spiders considered of high risk to humans: Latrodectus is present in rural areas, Phoneutria is restricted to small regions while Loxosceles is distributed throughout the country. Accidents by Loxosceles represent around 4% of the total number produced by venomous animals in Argentina. The bite is accidental and may produce considerable local necrosis with scar formation and ulcers of slow and difficult healing that may require surgical repair. Some bitten people may suffer from intravascular hemolysis, disseminated coagulation and acute renal insufficiency leading to death. Despite the great number of studies performed on Loxosceles venoms, at present, the physiopathological course of poisoning is not clear and there is not common criteria for its treatment. In this review, biological and epidemiological data of this spider are described as well as the venom composition and the possible participation of its components in the poisoning. These data provide biological and biochemical tools to understand the course of poisoning and to have better criteria for the treatment and prevention of these accidents and their complications. PMID:11965857

  18. Widowers' accounts of maternal mortality among women of low socioeconomic status in Nigeria.

    Science.gov (United States)

    Nwokocha, Ezebunwa Ethelbert

    2012-09-01

    The research is based on information collected on 50 deceased Nigerian women of low socioeconomic status in different locations of the country including Lagos, Ibadan, Kaduna, Zaria, Minna, Enugu, and Port-Harcourt among others. They had some common characteristics such as low levels of education, involvement in petty trading and were clients of a microfinance bank as small loan receivers. Primary data were generated mainly through verbal autopsy with widowers employing in-depth interviews and key informant interviews. In addition, unobtrusive observation was carried out in these locations to ascertain in some instances the distance between the deceased homes and health facilities patronised by the women. Secondary data were specific to death certificates of the deceased supplied by the widowers. Both ethnographic summaries and content analysis were employed in data analysis to account for contextual differences, especially in a multicultural society like Nigeria. The findings implicated several issues that are taken for granted at the micro-family and macro-society levels. It specifically revealed that small loans alone are not sufficient to empower poor women to make meaningful contributions to their own reproductive health in a patriarchal society like Nigeria. Results also indicated that cultural differences as well as rural-urban dichotomy were not proximate determinants of maternal behaviour; the latter rather finds expression in low socioeconomic status. Consequently, policy relevant recommendations that could contribute to significant maternal mortality reduction were proffered. PMID:23437504

  19. [The social relegation of widows living with HIV in the time of ART in Senegal].

    Science.gov (United States)

    Desclaux, A; Boye, S; Taverne, B

    2014-10-01

    While prolonged widowhood is unusual in Senegalese society, some women living with HIV receiving antiretroviral therapy for ten years remained widows. Are they maintained in this situation for refusing or being unable to remarry? To understand the conditions and the reasons for this lack of "matrimonial normalization", a qualitative interview study was conducted in Dakar with 31 widows. Their living conditions are mostly marked by economic difficulties, dependence on host families, and responsibilities visà-vis their children. They refuse to remarry, regret not being able to, or wish to without success, despite the existence locally of social forms of marital union that would respond to their situation. The refusal to disclose their HIV status combined with self-stigma prevent them from improving their condition. This form of social vulnerability that remains beyond the restoration of health is ignored by public policy and HIV/AIDS community based organizations claims. It should be acknowledged and considered for defending PLWAs' rights. PMID:24563114

  20. Wayanad widows: A study of sustainable rural economic development using renewable energy technology for micro enterprise in Kerala, India

    Science.gov (United States)

    Voorhees, Maire Claire

    This thesis examines the situation of the farmer widows of Wayanad, Kerala through exploration of the underlying agricultural and economic issues leading to farmers' suicides, the current state of the environment in the Wayanad District of Kerala, India, and an economic model of micro-entrepreneurship to address economic and social issues of the surviving widows. Quantitative and qualitative research methods were performed through the assessment and document analysis of archive, newspaper, and published reports to gain a macro perspective. The Environmental Vulnerability Index was used as a tool to evaluate and organize findings of the current environmental conditions in the region. This thesis supports the sustainability concept of considering the economic, ecological, and social impacts when identifying economic development pathways. The goal was to explore the appropriateness of small household solar systems as vehicle in the micro-enterprise model to be a sustainable alternative economic pathway to agriculture for the farmer widows of Wayanad.

  1. Evidence for competition between carnivorous plants and spiders.

    Science.gov (United States)

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

    2010-10-01

    Several studies have demonstrated that competition between disparate taxa can be important in determining community structure, yet surprisingly, to our knowledge, no quantitative studies have been conducted on competition between carnivorous plants and animals. To examine potential competition between these taxa, we studied dietary and microhabitat overlap between pink sundews (Drosera capillaris) and wolf spiders (Lycosidae) in the field, and conducted a laboratory experiment examining the effects of wolf spiders on sundew fitness. In the field, we found that sundews and spiders had a high dietary overlap with each other and with the available arthropod prey. Associations between sundews and spiders depended on spatial scale: both sundews and spiders were found more frequently in quadrats with more abundant prey, but within quadrats, spiders constructed larger webs and located them further away from sundews as the total sundew trapping area increased, presumably to reduce competition. Spiders also constructed larger webs when fewer prey were available. In the laboratory, our experiment revealed that spiders can significantly reduce sundew fitness. Our findings suggest that members of the plant and animal kingdoms can and do compete. PMID:20462904

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

    Science.gov (United States)

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

    2015-06-01

    Spider-phobic individuals are characterized by exaggerated expectancies to be faced with spiders (so-called encounter expectancy bias). Whereas phobic responses have been linked to brain systems mediating fear, little is known about how the recruitment of these systems relates to exaggerated expectancies of threat. We used fMRI to examine spider-phobic and control participants while they imagined visiting different locations in a forest after having received background information about the likelihood of encountering different animals (spiders, snakes, and birds) at these locations. Critically, imagined encounter expectancies modulated brain responses differently in phobics as compared with controls. Phobics displayed stronger negative modulation of activity in the lateral prefrontal cortex, precuneus, and visual cortex by encounter expectancies for spiders, relative to snakes or birds (within-participants analysis); these effects were not seen in controls. Between-participants correlation analyses within the phobic group further corroborated the hypothesis that these phobia-specific modulations may underlie irrationality in encounter expectancies (deviations of encounter expectancies from objective background information) in spider phobia; the greater the negative modulation a phobic participant displayed in the lateral prefrontal cortex, precuneus, and visual cortex, the stronger was her bias in encounter expectancies for spiders. Interestingly, irrationality in expectancies reflected in frontal areas relied on right rather than left hemispheric deactivations. Our data accord with the idea that expectancy biases in spider phobia may reflect deficiencies in cognitive control and contextual integration that are mediated by right frontal and parietal areas. PMID:25694215

  3. Forest floor spiders of woodlots in an agricultural landscape

    NARCIS (Netherlands)

    Mabelis, A.

    1996-01-01

    An inventory of spiders was made in woodlots, which are situated in an agricultural landscape in the eastern part of the Netherlands. Aim of the study was to test the hypotheses that good dispersers, like spiders, will be distributed randomly over habitat patches and consequently, that there will be

  4. Living Arrangements of Widowed Elderly Women and their Differentials: A Study in an Urban Setting of Tamil Nadu, India

    Directory of Open Access Journals (Sweden)

    Neelu Singh

    2012-03-01

    Full Text Available Living arrangements in the twilight of life is a matter of primary concern for elderly widowedwomen. In view of this, an attempt is made to examine the effect of backgroundcharacteristics on the living arrangements of the widowed elderly women making use of thedata collected from 330 elderly widowed women from Coimbatore city, Tamil Nadu withfrequency and cross-tabular analyses as well as chi-square test of significance. The studyfound that slightly less than three-tenths of widowed women are „old-old‟ (75+ years. Onthe other hand, three-fifths of elderly belonged to most backward / backward caste andmajority (63% of them illiterates. About two-fifths (42% of the elderly widowed women areliving with married son. The differentials of elderly living alone vs with children are mostlyin expected direction and highly significant (p<0.001 with an increase in the number ofearning members in the family, number of children living in the same area / city as well asthose who belonged to the households of high standard of living. On the other hand, thepercentage of widowed elderly who live alone has shown a clear increasing pattern with anincrease in occupational status and instrumental activities of daily living scale. Further, it isnoticed that the elderly who are living alone is higher among those who are feeling„unhealthy‟ as compared to those elderly widowed women as „healthy‟. All these percentagedifferentials are also turned out as significant at different levels of extent (p<0.001 or p<0.05.Based on these findings a few policy implications have been postulated.

  5. Vision in the nocturnal wandering spider Leucorchestris arenicola (Araneae: Sparassidae)

    DEFF Research Database (Denmark)

    Nørgaard, Thomas; Nilsson, Dan-Eric; Henschel, Joh R; Garm, Anders; Wehner, Rüdiger

    At night the Namib Desert spider Leucorchestris arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders' eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role...... in the nocturnal navigational performances of L. arenicola. After excluding two or three pairs of eyes, the spiders were found to be able to navigate successfully using only their lateral eyes or only their anterior median eyes. Measurement of the eyes' visual fields showed that the secondary eyes...... and temporal resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape...

  6. SOCIAL RIGHT AND ITS APPLICATION FOR MARTYR'S WIDOW, ORPHAN AND WAR VETERAN-VICTIM WHO NEEDED SPECIAL CARE AND PROTECTION

    Directory of Open Access Journals (Sweden)

    Bülent KARA

    2010-04-01

    Full Text Available In respect to social state principle, the 61’ st article of the Constitution is allocated for disadvantaged people. Because of special situations of Turkey, social rights of the casualties, the orphans and the widows, the handicapped and the veterans were determined and organized in this article. The main aim of this study is to evaluate the laws, policies and problems of the casualties, the orphans and the widows, the handicapped and the veterans who were preserved by the Constitution and some laws.

  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. PMID:23872119

  8. Predator-prey coevolution: Australian native bees avoid their spider predators.

    OpenAIRE

    Heiling, A M; Herberstein, M E

    2004-01-01

    Australian crab spiders Thomisus spectabilis manipulate visual flower signals to lure introduced Apis mellifera. We gave Australian native bees, Austroplebia australis, the choice between two white daisies, Chrysanthemum frutescens, one of them occupied by a crab spider. The colour contrast between flowers and spiders affected the behaviour of native bees. Native bees approached spider-occupied flowers more frequently. However, native bees avoided flowers occupied by spiders and landed on vac...

  9. Does Government subsidy for costs of medical and pharmaceutical services result in higher service utilization by older widowed women in Australia?

    Directory of Open Access Journals (Sweden)

    Tooth Leigh R

    2012-06-01

    Full Text Available Abstract Background In Australia, Medicare, the national health insurance system which includes the Medical Benefits Scheme (MBS and Pharmaceutical Benefits Scheme (PBS, provides partial coverage for most medical services and pharmaceuticals. For war widows, the Department of Veterans’ Affairs (DVA covers almost the entire cost of their health care. The objective of this study was to test whether war widows have higher usage of medical services and pharmaceuticals. Methods Data were from 730 women aged 70–84 years (mostly World War II widows participating in the Australian Longitudinal Study on Women’s Health who consented to data linkage to Medicare Australia. The main outcome measures were PBS costs, claims, co-payments and scripts presented, and MBS total costs, claims and gap payments for medical services in 2005. Results There was no difference between the war widows and similarly aged widows in the Australian population without DVA support on use of medical services. While war widows had more pharmaceutical prescriptions filled they generated equivalent total costs, number of claims and co-payments for pharmaceuticals than widows without DVA support. Conclusions Older war widows are not using more medical services and pharmaceuticals than other older Australian women despite having financial incentives to do so.

  10. Black to Black

    DEFF Research Database (Denmark)

    Langkjær, Michael Alexander

    2012-01-01

    Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as...... is hinted by Rudyard Kipling’s illustration of ‘The [Black] Cat That Walked by Himself’ in his classic children’s tale). It was well understood by uniformed Anarchists, Fascists and the SS that there is an assertive presence connected with the black-clad figure. The paradox of black’s abstract elegance......-styled references to, among other things, the culturally and ideologically effervescent interwar-period have made me curious as to what alternative possibilities – for instance ‘emancipation’ – a comparative analysis might disclose concerning the visual rhetoric of black. Thus, in conclusion, it is briefly...

  11. 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.

  12. Brown spider dermonecrotic toxin directly induces nephrotoxicity

    International Nuclear Information System (INIS)

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

  13. Prolonged grief disorder and depression in widows due to the Rwandan genocide.

    Science.gov (United States)

    Schaal, Susanne; Elbert, Thomas; Neuner, Frank

    2009-01-01

    Should pathological grief be viewed as a nosological category, separate from other forms of mental diseases? Diagnostic criteria for "Prolonged Grief Disorder" (PGD) have recently been specified by Prigerson and her coworkers. We interviewed a total of 40 widows who had lost their husbands during the Rwandan genocide in 1994. We assessed Major Depression using the Mini-International Neuropsychiatric Interview (M.I.N.I.) and prolonged grief reactions with the PG-13. In order to examine the distinctiveness of the two syndromes we performed a multitrait correlational matrix analysis using modified versions of Generalized Proximity Functions (GPFs). 12.5% (n = 5) of the sample fulfilled the criteria for a diagnosis of PGD; 40% (n = 16) met criteria for Major Depressive Episode. The two syndromes were strongly associated. No discriminant validity was found between the two constructs suggesting that PGD may rather be an appearance of depression than a separate nosological entity. PMID:19791517

  14. Widows and Wenches: Single Women in Eighteenth-Century Urban Economies

    DEFF Research Database (Denmark)

    Simonton, Deborah Leigh

    2013-01-01

    Across Europe, windowed and single women claimed a place for themselves in the urban economy through their work and business roles. Through marriage, most women gained strength, position and status in the patriarchal society of the eighteenth century. Yet, singletons could utilise an array of...... towns in Britain as well as on commercial centres of continental Europe. It will address the issue of how the gendered structure of the growing commercial town influenced singletons’ activities and conversely how the important contributions women made to the urban economy shaped that economy and...... relationships within the transnational urban economy. It is based on primary research as well as the number of micro studies which have touched on or addressed widows and singlewomen. It also links to the growing interest in singletons and recognizes the importance of lifecycle when exploring female agency....

  15. Time-dependent motor properties of multipedal molecular spiders

    Science.gov (United States)

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

    2011-09-01

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

  16. 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.

  17. The effects of neurotoxins and radiation on the neuromuscular junction of the mouse: a physiological and morphological study

    International Nuclear Information System (INIS)

    Some of the factors controlling axonal growth are studied by observing the effects of botulinum toxin, black widow spider venom and X-irradiation on teh neuromuscular junction in mice. Irradiation alone caused no changes since radiation is believed to affect only the Schwann cells. Irradiation prior to the administration of botulinum delayed the recovery of transmission and led to the failure of maturation and myelination of newly formed axons; this illustrates the importance of the Schwann cell for continued growth, functional maturation and myelination of axons. The effect of black widow spider venom on the end-plates was degeneration of the nerve terminals within a few hours but after a few days there was regeneration and restoration of normal transmission. The effects of black widow spider venom on muscles paralysed by botulinum were also studied; the recovery from the action of botulinum was greatly accelerated by the venom and axonal sprouting was either abolished or greatly reduced. (U.K.)

  18. 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...

  19. Microcirculation abnormalities provoked by Loxosceles spiders' envenomation.

    Science.gov (United States)

    Cristina de Oliveira-Lima, Kátia; Farsky, Sandra Helena P; Lopes, Priscila Hess; de Andrade, Rute Maria Gonçalves; van den Berg, Carmen W; Tambourgi, Denise V

    2016-06-15

    Loxoscelism is caused by envenomation by spiders from Loxosceles genus. Clinical symptoms only appear a few hours after envenomation and can evolve in local reactions, such as dermonecrosis, and systemic reactions, including intravascular haemolysis, intravascular coagulation and renal failure. Considering that alterations in the microcirculatory network are involved in the pathogenesis of different diseases, including the inflammatory process, the aim of this study was to investigate the action of venoms of males and females of Loxosceles intermedia and Loxosceles laeta on the microcirculatory network and examine the systemic production of inflammatory mediators in a murine model of loxoscelism. We observed that during systemic envenomation, the alterations in the microcirculation include increase in the number of rolling cells, which was more intense in animals injected with female Loxosceles spider venoms. This positively correlated with increase in TNF-α and NO serum levels, induction of which was higher by female venoms when compared with male venoms. The increase of leukocytes rolling was not accompanied by increase of cell adhesion. The absence of leukocyte extravasation may explain why in mice, in contrast to humans, no cutaneous loxoscelism occurs. Thus, targeting the neutrophil adhesion and extravasation in Loxosceles envenomed patients may prevent cutaneous pathology. PMID:26256792

  20. 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. PMID:16676522

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

    Science.gov (United States)

    Silva, Luciano P; Rech, Elibio L

    2013-01-01

    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. PMID:24345771

  2. 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...

  3. Simulation for Evolution of the Australian Netting Spider PM Eye

    OpenAIRE

    Williams, Vernon

    2011-01-01

    This paper reports on a simulated evolution project, which had the goal of simulating the refractive components of the PM eye of Australian netting spider diopis subrufus on a desktop computer. The model for the simulation is the anatomy of the eye described by Blest and Land [Ble & Lan 1977]. The evolution simulation was able to produce hundreds of eyes with equivalent optical qualities to the measured eyes for the phenotype of the netting spider. These artificially evolved eyes began to occ...

  4. 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.

  5. SPIDer: Saccharomyces protein-protein interaction database

    Directory of Open Access Journals (Sweden)

    Li Zhenbo

    2006-12-01

    Full Text Available Abstract Background Since proteins perform their functions by interacting with one another and with other biomolecules, reconstructing a map of the protein-protein interactions of a cell, experimentally or computationally, is an important first step toward understanding cellular function and machinery of a proteome. Solely derived from the Gene Ontology (GO, we have defined an effective method of reconstructing a yeast protein interaction network by measuring relative specificity similarity (RSS between two GO terms. Description Based on the RSS method, here, we introduce a predicted Saccharomyces protein-protein interaction database called SPIDer. It houses a gold standard positive dataset (GSP with high confidence level that covered 79.2% of the high-quality interaction dataset. Our predicted protein-protein interaction network reconstructed from the GSPs consists of 92 257 interactions among 3600 proteins, and forms 23 connected components. It also provides general links to connect predicted protein-protein interactions with three other databases, DIP, BIND and MIPS. An Internet-based interface provides users with fast and convenient access to protein-protein interactions based on various search features (searching by protein information, GO term information or sequence similarity. In addition, the RSS value of two GO terms in the same ontology, and the inter-member interactions in a list of proteins of interest or in a protein complex could be retrieved. Furthermore, the database presents a user-friendly graphical interface which is created dynamically for visualizing an interaction sub-network. The database is accessible at http://cmb.bnu.edu.cn/SPIDer/index.html. Conclusion SPIDer is a public database server for protein-protein interactions based on the yeast genome. It provides a variety of search options and graphical visualization of an interaction network. In particular, it will be very useful for the study of inter-member interactions

  6. Spider-mite problems and control in Taiwan.

    Science.gov (United States)

    Ho, C C

    2000-01-01

    Problems with spider mites first appeared in Taiwan in 1958, eight years after the importation of synthetic pesticides, and the mites evolved into major pests on many crops during the 1980s. Of the 74 spider mite species recorded from Taiwan 10 are major pests, with Tetranychus kanzawai most important, followed by T. urticae, Panonychus citri, T. cinnabarinus, T. truncatus and Oligonychus litchii. Most crops suffer from more than one species. Spider mites reproduce year-round in Taiwan. Diapause occurs only in high-elevation areas. Precipitation is the most important abiotic factor restricting spider-mite populations. Control is usually accomplished by applying chemicals. Fifty acaricides are currently registered for the control of spider mites. Acaricide resistance is a serious problem, with regional variation in resistance levels. Several phytoseiid mites and a chrysopid predator have been studied for control of spider mites with good effect. Efforts to market these predators should be intensified so that biological control can be a real choice for farmers. PMID:11156169

  7. 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.

  8. Rates and risks for prolonged grief disorder in a sample of orphaned and widowed genocide survivors

    Directory of Open Access Journals (Sweden)

    Jacob Nadja

    2010-07-01

    Full Text Available Abstract Background The concept of Prolonged Grief Disorder (PGD has been defined in recent years by Prigerson and co-workers, who have developed and empirically tested consensus and diagnostic criteria for PGD. Using these most recent criteria defining PGD, the aim of this study was to determine rates of and risks for PGD in survivors of the 1994 Rwandan genocide who had lost a parent and/or the husband before, during or after the 1994 events. Methods The PG-13 was administered to 206 orphans or half orphans and to 194 widows. A regression analysis was carried out to examine risk factors of PGD. Results 8.0% (n = 32 of the sample met criteria for PGD with an average of 12 years post-loss. All but one person had faced multiple losses and the majority indicated that their grief-related loss was due to violent death (70%. Grief was predicted mainly by time since the loss, by the violent nature of the loss, the severity of symptoms of posttraumatic stress disorder (PTSD and the importance given to religious/spiritual beliefs. By contrast, gender, age at the time of bereavement, bereavement status (widow versus orphan, the number of different types of losses reported and participation in the funeral ceremony did not impact the severity of prolonged grief reactions. Conclusions A significant portion of the interviewed sample continues to experience grief over interpersonal losses and unresolved grief may endure over time if not addressed by clinical intervention. Severity of grief reactions may be associated with a set of distinct risk factors. Subjects who lose someone through violent death seem to be at special risk as they have to deal with the loss experience as such and the traumatic aspects of the loss. Symptoms of PTSD may hinder the completion of the mourning process. Religious beliefs may facilitate the mourning process and help to find meaning in the loss. These aspects need to be considered in the treatment of PGD.

  9. Distal-less homeobox genes of insects and spiders: genomic organization, function, regulation and evolution.

    Science.gov (United States)

    Chen, Bin; Piel, William H; Monteiro, Antónia

    2016-06-01

    The Distal-less (Dll) genes are homeodomain transcription factors that are present in most Metazoa and in representatives of all investigated arthropod groups. In Drosophila, the best studied insect, Dll plays an essential role in forming the proximodistal axis of the legs, antennae and analia, and in specifying antennal identity. The initiation of Dll expression in clusters of cells in mid-lateral regions of the Drosophila embryo represents the earliest genetic marker of limbs. Dll genes are involved in the development of the peripheral nervous system and sensitive organs, and they also function as master regulators of black pigmentation in some insect lineages. Here we analyze the complete genomes of six insects, the nematode Caenorhabditis elegans and Homo sapiens, as well as multiple Dll sequences available in databases in order to examine the structure and protein features of these genes. We also review the function, expression, regulation and evolution of arthropod Dll genes with emphasis on insects and spiders. PMID:26898323

  10. 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...

  11. Black rings

    International Nuclear Information System (INIS)

    A black ring is a five-dimensional black hole with an event horizon of topology S1 x S2. We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)

  12. Somatic panic-attack equivalents in a community sample of Rwandan widows who survived the 1994 genocide.

    Science.gov (United States)

    Hagengimana, Athanase; Hinton, Devon; Bird, Bruce; Pollack, Mark; Pitman, Roger K

    2003-01-25

    The present study is the first to attempt to determine rates of panic attacks, especially 'somatically focused' panic attacks, panic disorder, symptoms of post-traumatic stress disorder (PTSD), and depression levels in a population of Rwandans traumatized by the 1994 genocide. The following measures were utilized: the Rwandan Panic-Disorder Survey (RPDS); the Beck Depression Inventory (BDI); the Harvard Trauma Questionnaire (HTQ); and the PTSD Checklist (PCL). Forty of 100 Rwandan widows suffered somatically focused panic attacks during the previous 4 weeks. Thirty-five (87%) of those having panic attacks suffered panic disorder, making the rate of panic disorder for the entire sample 35%. Rwandan widows with panic attacks had greater psychopathology on all measures. Somatically focused panic-attack subtypes seem to constitute a key response to trauma in the Rwandan population. Future studies of traumatized non-Western populations should carefully assess not only somatoform disorder but also somatically focused panic attacks. PMID:12581815

  13. The Language of Revolution and the Power of Storytelling in The Pregnant Widow

    Directory of Open Access Journals (Sweden)

    Alaa Alghamdi

    2014-01-01

    Full Text Available Martin Amis uses the language of revolution to describe the newly altered social circumstances at the height of the sexual revolution in his semi-autobiographical novel The Pregnant Widow. The concept of a ‘language of revolution’ as well as second- and third-wave feminist scholarship is applied to a textual analysis of the novel. Amis’s brand of satire creates a sense of displacement and challenges existing perceptions about gender, culture and sexuality, exposing them as constructed and changeable norms. Moreover, it becomes clear that the author is skeptical about the benefits of the sexual revolution for either gender, and that he views its liberating aspects as unfulfilled, particularly for women. Given that Amis names one of his characters Scheherazade, evoking the legendary heroine of The Arabian Nights, the importance of storytelling in the novel is also examined and found to be a potentially redeeming force.Keywords: Martin Amis, sexual revolution, feminism, satire, gender, revolution

  14. Ecopsychosocial Aspects of Human–Tiger Conflict: An Ethnographic Study of Tiger Widows of Sundarban Delta, India

    OpenAIRE

    Chowdhury, Arabinda N.; Ranajit Mondal; Arabinda Brahma; Biswas, Mrinal K.

    2016-01-01

    AIMS Human–tiger conflict (HTC) is a serious public health issue in Sundarban Reserve Forest, India. HTC is a continued concern for the significant mortality and morbidity of both human and tiger population. This is the first comprehensive report on Sundarban tiger–human conflicts and its impact on widows whose husbands were killed by tigers. The study attempts to explore the situation analysis of HTC and the aftermath of the incident including bereavement and coping, the cultural stigma rela...

  15. Somatic panic-attack equivalents in a community sample of Rwandan widows who survived the 1994 genocide

    OpenAIRE

    Hagengimana, Athanase; Hinton, Devon; Bird, Bruce; Pollack, Mark; Pitman, roger k

    2003-01-01

    The present study is the first to attempt to determine rates of panic attacks, especially ‘somatically focused’ panic attacks, panic disorder, symptoms of post-traumatic stress disorder (PTSD), and depression levels in a population of Rwandans traumatized by the 1994 genocide. The following measures were utilized: the Rwandan Panic-Disorder Survey (RPDS); the Beck Depression Inventory (BDI); the Harvard Trauma Questionnaire (HTQ); and the PTSD Checklist (PCL). Forty of 100 Rwandan widows suff...

  16. 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...

  17. Does Government subsidy for costs of medical and pharmaceutical services result in higher service utilization by older widowed women in Australia?

    OpenAIRE

    Tooth Leigh R; Hockey Richard; Treloar Susan; McClintock Christine; Dobson Annette

    2012-01-01

    Abstract Background In Australia, Medicare, the national health insurance system which includes the Medical Benefits Scheme (MBS) and Pharmaceutical Benefits Scheme (PBS), provides partial coverage for most medical services and pharmaceuticals. For war widows, the Department of Veterans’ Affairs (DVA) covers almost the entire cost of their health care. The objective of this study was to test whether war widows have higher usage of medical services and pharmaceuticals. Methods Data were from 7...

  18. 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. PMID

  19. Beat sampling accuracy in estimating spruce spider mite (Acari: Tetranychidae) populations and injury on juniper.

    Science.gov (United States)

    Shrewsbury, Paula M; Hardin, Mark R

    2004-08-01

    The use of a standardized beat sampling method for estimating spruce spider mite, Oligonychus ununguis (Jacobi) (Acari: Tetranychidae), densities on a widely used evergreen ornamental plant species, Juniperus chinensis variety 'Sargentii' A. Henry (Cupressaceae), was examined. There was a significant positive relationship between total spruce spider mite densities and spider mite densities from beat sampling on juniper. The slope and intercept of the relationship may be used by pest managers to predict total spider mite densities on plants from beat sample counts. Beat sampling dramatically underestimates the total number of spider mites on a foliage sample. The relationships between spruce spider mite feeding injury and spider mite density estimates from beat sampling juniper foliage and total spider mite counts on foliage were also examined. There was a significant positive relationship between spruce spider mite density as estimated from beat sampling and injury to the plants. There was a similar positive relationship between the total number of spruce spider mites and injury to the plants, suggesting that a pest manager could use beat sampling counts to estimate plant injury and related thresholds. These findings have important implications to decision-making for spruce spider mite control, especially as it relates to threshold levels and determining rates of predator releases. Further assessment of the effectiveness of beat and other sampling methods across multiple spider mite- host plant associations needs to be examined to enable pest managers to select sampling plans that are feasible and reliable. PMID:15384359

  20. Radiation Safety System for SPIDER Neutral Beam Accelerator

    Science.gov (United States)

    Sandri, S.; Coniglio, A.; D'Arienzo, M.; Poggi, C.

    2011-12-01

    SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

  1. Radiation Safety System for SPIDER Neutral Beam Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sandri, S.; Poggi, C. [ENEA, Radiation Protection Institute, IRP-FUAC, Frascati (Italy); Coniglio, A. [Medical Physics Department, S. Giovanni Calibita Hospital, Fatebenefratelli, Isola Tiberina, Roma (Italy); D' Arienzo, M. [ENEA, Ionizing Radiation Metrology National Institute, METR, Casaccia, Rome (Italy)

    2011-12-13

    SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

  2. Biased motion and molecular motor properties of bipedal spiders

    Science.gov (United States)

    Samii, Laleh; Linke, Heiner; Zuckermann, Martin J.; Forde, Nancy R.

    2010-02-01

    Molecular spiders are synthetic molecular motors featuring multiple legs that each can interact with a substrate through binding and cleavage. Experimental studies suggest the motion of the spider in a matrix is biased toward uncleaved substrates and that spider properties such as processivity can be altered by changing the binding strength of the legs to substrate [R. Pei, S. K. Taylor, D. Stefanovic, S. Rudchenko, T. E. Mitchell, and M. N. Stojanovic, J. Am. Chem. Soc. 128, 12693 (2006)]. We investigate the origin of biased motion and molecular motor properties of bipedal spiders using Monte Carlo simulations. Our simulations combine a realistic chemical kinetic model, hand-over-hand or inchworm modes of stepping, and the use of a one-dimensional track. We find that stronger binding to substrate, cleavage and spider detachment from the track are contributing mechanisms to population bias. We investigate the contributions of stepping mechanism to speed, randomness parameter, processivity, coupling, and efficiency, and comment on how these molecular motor properties can be altered by changing experimentally tunable kinetic parameters.

  3. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    Energy Technology Data Exchange (ETDEWEB)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

    2010-08-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  4. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    International Nuclear Information System (INIS)

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  5. Flow Characteristics Analysis of Widows' Creek Type Control Valve for Steam Turbine Control

    International Nuclear Information System (INIS)

    The steam turbine converts the kinetic energy of steam to mechanical energy of rotor blades in the power conversion system of fossil and nuclear power plants. The electric output from the generator of which the rotor is coupled with that of the steam turbine depends on the rotation velocity of the steam turbine bucket. The rotation velocity is proportional to the mass flow rate of steam entering the steam turbine through valves and nozzles. Thus, it is very important to control the steam mass flow rate for the load following operation of power plants. Among various valves that control the steam turbine, the control valve is most significant. The steam flow rate is determined by the area formed by the stem disk and the seat of the control valve. While the ideal control valve linearly controls the steam mass flow rate with its stem lift, the real control valve has various flow characteristic curves pursuant to the stem lift type. Thus, flow characteristic curves are needed to precisely design the control valves manufactured for the operating conditions of nuclear power plants. OMEGA (Optimized Multidimensional Experiment Geometric Apparatus) was built to experimentally study the flow characteristics of steam flowing inside the control valve. The Widows' Creek type control valve was selected for reference. Air was selected as the working fluid in the OMEGA loop to exclude the condensation effect in this simplified approach. Flow characteristic curves were plotted by calculating the ratio of the measured mass flow rate versus the theoretical mass flow rate of the air. The flow characteristic curves are expected to be utilized to accurately design and operate the control valve for fossil as well as nuclear plants. (authors)

  6. Black Consciousness

    Science.gov (United States)

    Hraba, Joseph; Siegman, Jack

    1974-01-01

    Black militancy is treated as an instance of class consciousness with criteria and scales developed to measure black consciousness and "self-placement" into black consciousness. These dimensions are then investigated with respect to the social and symbolic participation in the ideology of the black movement on the part of a sample of black…

  7. Interactions Between the Chilean Recluse Spider (Araneae: Sicariidae) and an Araneophagic Spitting Spider (Araneae: Scytodidae).

    Science.gov (United States)

    Canals, Mauricio; Arriagada, Nicolás; Solís, Rigoberto

    2015-03-01

    In Chile, all necrotic arachnidism is attributed to the Chilean recluse spider, Loxosceles laeta Nicolet, a species that shares the microenvironmental habitats with the spitting spider Scytodes globula Nicolet. The latter species has been proposed as a potential predator of L. laeta. For this research, we studied the interaction between both species during individual encounters to assess the possibility of population regulation of L. laeta cohorts exposed to this potential predator. We found that in most encounters S. globula prevailed. Also, S. globula preys on spiderlings of L. laeta, with a population effect on cohorts of this species. These findings suggest that S. globula may be influencing L. laeta populations in central Chile. The population regulation of L. laeta by predation would be important because this species, in the absence of predators, has a high reproductive rate, and it can maintain populations of large size. However according to our results, although S. globula may aid in the reduction of both spiderling and adult L. laeta populations, and perhaps other Loxosceles species, it is insufficient for biological control of Loxosceles species. Its presence together with other control measures such as hygiene of the rooms can help to decrease loxoscelism incidence. PMID:26336293

  8. Subsocial behaviour and brood adoption in mixed-species colonies of two theridiid spiders

    DEFF Research Database (Denmark)

    Grinsted, Lena; Agnarsson, Ingi; Bilde, Trine

    2012-01-01

    Cooperation and group living often evolves through kin selection. However, associations between unrelated organisms, such as different species, can evolve if both parties benefit from the interaction. Group living is rare in spiders, but occurs in cooperative, permanently social spiders, as well as...... in territorial, colonial spiders. Mixed species spider colonies, involving closely related species, have rarely been documented. We examined social interactions in newly discovered mixed-species colonies of theridiid spiders on Bali, Indonesia. Our aim was to test the degree of intra- and...

  9. Prey interception drives web invasion and spider size determines successful web takeover in nocturnal orb-web spiders

    Directory of Open Access Journals (Sweden)

    Wenjin Gan

    2015-10-01

    Full Text Available A striking feature of web-building spiders is the use of silk to make webs, mainly for prey capture. However, building a web is energetically expensive and increases the risk of predation. To reduce such costs and still have access to abundant prey, some web-building spiders have evolved web invasion behaviour. In general, no consistent patterns of web invasion have emerged and the factors determining web invasion remain largely unexplored. Here we report web invasion among conspecifics in seven nocturnal species of orb-web spiders, and examined the factors determining the probability of webs that could be invaded and taken over by conspecifics. About 36% of webs were invaded by conspecifics, and 25% of invaded webs were taken over by the invaders. A web that was built higher and intercepted more prey was more likely to be invaded. Once a web was invaded, the smaller the size of the resident spider, the more likely its web would be taken over by the invader. This study suggests that web invasion, as a possible way of reducing costs, may be widespread in nocturnal orb-web spiders.

  10. Thermal architecture for the SPIDER flight cryostat

    CERN Document Server

    Gudmundsson, J E; Amiri, M; Benton, S J; Bihary, R; Bock, J J; Bond, J R; Bonetti, J A; Bryan, S A; Chiang, H C; Contaldi, C R; Crill, B P; O'Dea, D; Farhang, M; Filippini, J P; Fissel, L M; Gandilo, N N; Golwala, S R; Halpern, M; Hasselfield, M; Helson, K R; 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; 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; 10.1117/12.857925

    2011-01-01

    We describe the cryogenic system for SPIDER, a balloon-borne microwave polarimeter that will map 8% of the sky with degree-scale angular resolution. The system consists of a 1284 L liquid helium cryostat and a 16 L capillary-filled superfluid helium tank, which provide base operating temperatures of 4 K and 1.5 K, respectively. Closed-cycle helium-3 adsorption refrigerators supply sub-Kelvin cooling power to multiple focal planes, which are housed in monochromatic telescope inserts. The main helium tank is suspended inside the vacuum vessel with thermally insulating fiberglass flexures, and shielded from thermal radiation by a combination of two vapor cooled shields and multi-layer insulation. This system allows for an extremely low instrumental background and a hold time in excess of 25 days. The total mass of the cryogenic system, including cryogens, is approximately 1000 kg. This enables conventional long duration balloon flights. We will discuss the design, thermal analysis, and qualification of the cryog...

  11. How spiders practice aggressive and Batesian mimicry

    Institute of Scientific and Technical Information of China (English)

    Ximena J.NELSON; Robert R.JACKSON

    2012-01-01

    To understand communication,the interests of the sender and the receiver/s of signals should be considered separately.When our goal is to understand the adaptive significance of specific responses to specific signals by the receiver,questions about signal information are useful.However,when our goal is to understand the adaptive significance to the sender of generating a signal,it may be better to envisage the receiver's response to signals as part of the sender's extended phenotype.By making signals,a sender interfaces with the receiver's model of the world and indirectly manipulates its behaviour.This is especially clear in cases of mimicry,where animals use deceptive signals that indirectly manipulate the behaviour of receivers.Many animals adopt Batesian mimicry to deceive their predators,or aggressive mimicry to deceive their prey.We review examples from the literature on spiders to illustrate how these phenomena,traditionally thought of as distinct,can become entangled in a web of lies.

  12. Small Molecules from Spiders Used as Chemical Probes

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Kristensen, Anders S.; Strømgaard, Kristian

    2011-01-01

    Spiders are important species in ecological systems and as major predators of insects they are endowed with a plethora of low‐molecular‐weight natural products having intriguing biological activities. The isolation and biological characterization of these entities are well established, however......, only very recently have these compounds been used as templates for the design, synthesis, and biological evaluation of synthetic analogues. In contrast, the investigation of compounds responsible for chemical communication between spiders is far less developed, but recently new light has been shed onto...... the area of pheromones and allomones from spiders. Herein, we recapitulate these recent results, put them into perspective with previous findings, and provide an outlook for future studies of these chemotypes....

  13. Investigating the efficacy of attention bias modification in reducing high spider fear: The role of individual differences in initial bias

    OpenAIRE

    Fox, E; Zougkou, K; Ashwin, C; Cahill, S

    2015-01-01

    Background and objectives Attention Bias Modification (ABM) targets attention bias (AB) towards threat and is a potential therapeutic intervention for anxiety. The current study investigated whether initial AB (towards or away from spider images) influenced the effectiveness of ABM in spider fear. Methods AB was assessed with an attentional probe task consisting of spider and neutral images presented simultaneously followed by a probe in spider congruent or spider incongruent loca...

  14. 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.

  15. Predator perception of detritus and eggsac decorations spun by orb-web spiders Cyclosa octotuberculata: Do they function to camouflage the spiders?

    OpenAIRE

    Wenjin GAN, Fengxiang LIU, Zengtao ZHANG, Daiqin LI

    2010-01-01

    Camouflage is one of the most widespread and powerful strategies that animals use to make detection/recognition more difficult. Many orb-web spiders of the genus Cyclosa add prey remains, plant debris, moults, and/or eggsacs to their webs called web decorations. Web decorations resembling spider body colour pattern have been considered to camouflage the spider from predators. While this camouflage is obvious from a human’s perspective, it has rarely been investigated from a predator’s perspec...

  16. Silk reinforced with graphene or carbon nanotubes spun by spiders

    OpenAIRE

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

    2015-01-01

    Here, we report the production of silk incorporating graphene and carbon nanotubes directly by spider spinning, after spraying spiders with the corresponding aqueous dispersions. We observe a significant increment of the mechanical properties with respect to the pristine silk, in terms of fracture strength, Young's and toughness moduli. We measure a fracture strength up to 5.4 GPa, a Young's modulus up to 47.8 GPa and a toughness modulus up to 2.1 GPa, or 1567 J/g, which, to the best of our k...

  17. On some families of arbitrarily vertex decomposable spiders

    Directory of Open Access Journals (Sweden)

    Tomasz Juszczyk

    2010-01-01

    Full Text Available A graph \\(G\\ of order \\(n\\ is called arbitrarily vertex decomposable if for each sequence \\((n_1, ..., n_k\\ of positive integers such that \\(\\sum _{i=1}^{k} n_i = n\\, there exists a partition \\((V_1, ..., V_k\\ of the vertex set of \\(G\\ such that for every \\(i \\in \\{1, ...., k\\}\\ the set \\(V_i\\ induces a connected subgraph of \\(G\\ on \\(n_i\\ vertices. A spider is a tree with one vertex of degree at least \\(3\\. We characterize two families of arbitrarily vertex decomposable spiders which are homeomorphic to stars with at most four hanging edges.

  18. An image filtering technique for SPIDER visible tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fonnesu, N., E-mail: nicola.fonnesu@igi.cnr.it; Agostini, M.; Brombin, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2014-02-15

    The tomographic diagnostic developed for the beam generated in the SPIDER facility (100 keV, 50 A prototype negative ion source of ITER neutral beam injector) will characterize the two-dimensional particle density distribution of the beam. The simulations described in the paper show that instrumental noise has a large influence on the maximum achievable resolution of the diagnostic. To reduce its impact on beam pattern reconstruction, a filtering technique has been adapted and implemented in the tomography code. This technique is applied to the simulated tomographic reconstruction of the SPIDER beam, and the main results are reported.

  19. Synthesis and characterization of spider silk calcite composite

    Directory of Open Access Journals (Sweden)

    Svetlana Dmitrović

    2016-03-01

    Full Text Available Spider silk poses excellent mechanical properties, tenacity and elasticity and it has been used as a template for calcite mineralization to improve load bearing strength of osteoconductive calcite. The samples were obtained by mimicking biomineralization for five days in order to follow formation and growth of calcite on the surface of spider silk. Crystal phase was detected by XRD and FTIR spectroscopy. Microstructure, crystal size and its morphology were studied by means of FESEM. After two days of processing, pure calcite phase was obtained, and a size of the formed crystals increased with prolongation of biomineralization.

  20. Physical model of a floating trash boom to control aquatic weeds at the TVA Widows Creek Fossil Plant

    International Nuclear Information System (INIS)

    This paper reports that the Tennessee Valley Authority (TVA) Widows Creek Fossil plant seasonally encounters adverse accumulations of aquatic weeds at the intakes of the condenser cooling water pumps. To reduce the accumulations, a floating trash boom has been proposed for the intakes. To evaluate the hydraulic feasibility of a boom, a physical model of the intakes has been built at the TVA Engineering Laboratory. The model was used to determine the boom alignment and depth of skimming needed to successfully deflect weeds away from the intakes and provide self-cleaning

  1. The Spectacle of a Good-Half Widow: Performing Agency in the Human Rights Movement in Kashmir

    OpenAIRE

    Zia, Ather

    2013-01-01

    A woman sits in protest at one the busiest intersections in the capital city of Srinagar in the Indian controlled Kashmir. A voluminous scarf covers her hair, body and face, revealing only her eyes. Her gaze is downcast and tearful. In one hand she holds a photograph of a man with a name and date written across it, and in another, she has a placard which says, “Half-widow: Return my disappeared husband”.  The first time one beholds this spectacle, a lot of questions come to mind. Who is this ...

  2. Spiders do not escape reproductive manipulations by Wolbachia

    Directory of Open Access Journals (Sweden)

    Hendrickx Frederik

    2011-01-01

    Full Text Available Abstract Background Maternally inherited bacteria that reside obligatorily or facultatively in arthropods can increase their prevalence in the population by altering their hosts' reproduction. Such reproductive manipulations have been reported from the major arthropod groups such as insects (in particular hymenopterans, butterflies, dipterans and beetles, crustaceans (isopods and mites. Despite the observation that endosymbiont bacteria are frequently encountered in spiders and that the sex ratio of particular spider species is strongly female biased, a direct relationship between bacterial infection and sex ratio variation has not yet been demonstrated for this arthropod order. Results Females of the dwarf spider Oedothorax gibbosus exhibit considerable variation in the sex ratio of their clutches and were infected with at least three different endosymbiont bacteria capable of altering host reproduction i.e. Wolbachia, Rickettsia and Cardinium. Breeding experiments show that sex ratio variation in this species is primarily maternally inherited and that removal of the bacteria by antibiotics restores an unbiased sex ratio. Moreover, clutches of females infected with Wolbachia were significantly female biased while uninfected females showed an even sex ratio. As female biased clutches were of significantly smaller size compared to non-distorted clutches, killing of male embryos appears to be the most likely manipulative effect. Conclusions This represents to our knowledge the first direct evidence that endosymbiont bacteria, and in particular Wolbachia, might induce sex ratio variation in spiders. These findings are pivotal to further understand the diversity of reproductive phenotypes observed in this arthropod order.

  3. 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

  4. Czech Republic – the type material of spiders (Araneae)

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil; Kůrka, A.; Buchar, J.; Řezáč, M.

    2005-01-01

    Roč. 174, 1-4 (2005), s. 13-64. ISSN 0139-9543 R&D Projects: GA AV ČR(CZ) IAA6007401 Institutional research plan: CEZ:AV0Z50070508 Keywords : spiders * type material * Czech Republic Subject RIV: EG - Zoology

  5. Central European habitats inhabited by spiders with disjunctive distributions

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil

    2011-01-01

    Roč. 59, č. 2 (2011), s. 367-380. ISSN 1505-2249 Institutional research plan: CEZ:AV0Z50070508 Keywords : spiders * glacial relicts * boreomontane species Subject RIV: EH - Ecology, Behaviour Impact factor: 0.506, year: 2011

  6. Notes to the catalogue of spiders of the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil; Buchar, J.

    Budapest : Plant Protection Institute and Berzsenyi College, 2004 - (Samu, F.; Szinetár, C.), s. 221-224 ISBN 963 214 791 X. [European Colloquium of Arachnology /20./. Szombathely (HU), 22.07.2002-26.07.2002] Institutional research plan: CEZ:AV0Z5007907 Keywords : Czech Republic * spiders * catalogue Subject RIV: EG - Zoology

  7. Infanticide by a solitary koinobiont ichneumonid ectoparasitoid of spiders

    Science.gov (United States)

    Takasuka, Keizo; Matsumoto, Rikio

    2011-06-01

    When encountering an already parasitized host, a parasitoid's optimal choices (superparasitism, host rejection, host feeding or infanticide) seem to depend on the individual species' life history, because the same choice may have different fitness consequences. We demonstrate infanticide under laboratory conditions by a polysphinctine, Zatypota albicoxa, which is a solitary koinobiont ectoparasitoid of spiders. The female always removed any previously attached egg or larva from the body of the host spider, Parasteatoda tepidariorum, with a rubbing behaviour. She rubbed her ovipositor back and forth toward the undersurface of the attached egg or of the saddle under the attached larva to pry it off and laid an egg after removal. When removing a larva, the infanticidal female engaged exclusively in unfastening the `saddle' which fastens the larva to the body of the spider. All larvae were removed with the `saddle' attached to the ventral surface of the body. The female invested more time to remove the medium second and the large penultimate instar larvae than to remove eggs and first instar larvae because of the labour involved in unfastening the saddle. Oviposition with infanticide of the medium second and the penultimate instar larvae imposed more time upon the female than that on an unparasitized host. Removal of any previous occupant in spite of the associated labour costs suggests that infanticide will always be adaptive, no matter the time costs to Z. albicoxa, because so much is invested in attacking the host and because the parasitoid cannot detect whether the spider is already parasitized until she achieves subjugation.

  8. 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.…

  9. Black Eye

    Science.gov (United States)

    ... eyesight if not treated. If both eyes are black after a head injury, it could signify a skull fracture or other serious injury. Next Black Eye Symptoms Related Ask an Ophthalmologist Answers How ...

  10. Black tea

    Science.gov (United States)

    ... diuretic to increase urine flow. Some people use black tea for preventing tooth decay and kidney stones. In combination with various other products, black tea is used for weight loss. In foods, ...

  11. Spider diversity in coffee agroecosystems: the influence of agricultural intensification and aggressive ants.

    Science.gov (United States)

    Marín, Linda; Perfecto, Ivette

    2013-04-01

    Spiders are a very diverse group of invertebrate predators found in agroecosystems and natural systems. However, spider distribution, abundance, and eventually their ecological function in ecosystems can be influenced by abiotic and biotic factors such as agricultural intensification and dominant ants. Here we explore the influence of both agricultural intensification and the dominant arboreal ant Azteca instabilis on the spider community in coffee agroecosystems in southern Mexico. To measure the influence of the arboreal ant Azteca instabilis (F. Smith) on the spider community inhabiting the coffee layer of coffee agroecosystems, spiders were collected from coffee plants that were and were not patrolled by the ant in sites differing in agricultural intensification. For 2008, generalized linear mixed models showed that spider diversity was affected positively by agricultural intensification but not by the ant. However, results suggested that some spider species were associated with A. instabilis. Therefore, in 2009 we concentrated our research on the effect of A. instabilis on spider diversity and composition. For 2009, generalized linear mixed models show that spider richness and abundance per plant were significantly higher in the presence of A. instabilis. In addition, analyses of visual counts of insects and sticky traps data show that more resources were present in plants patrolled by the ant. The positive effect of A. instabilis on spiders seems to be caused by at least two mechanisms: high abundance of insects and protection against predators. PMID:23575009

  12. Contrasting responses of web-building spiders to deer browsing among habitats and feeding guilds.

    Science.gov (United States)

    Takada, Mayura; Baba, Yuki G; Yanagi, Yosuke; Terada, Saeko; Miyashita, Tadashi

    2008-08-01

    We examined web-building spider species richness and abundance in forests across a deer density gradient to determine the effects of sika deer browsing on spiders among habitats and feeding guilds. Deer decreased the abundance of web-building spiders in understory vegetation but increased their abundance in the litter layer. Deer seemed to affect web-building spiders in the understory vegetation by reducing the number of sites for webs because vegetation complexity was positively correlated with spider density and negatively correlated with deer density. In contrast, the presence of vegetation just above the litter layer decreased the spider density, and deer exerted a negative effect on this vegetation, possibly resulting in an indirect positive effect on spider density. The vegetation just above the litter layer may be unsuitable as a scaffold for building webs if it is too flexible to serve as a reliable web support, and may even hinder spiders from building webs on litter. Alternatively, the negative effect of this vegetation on spiders in the litter may be as a result of reduced local prey availability under the leaves because of the reduced accessibility of aerial insects. The response to deer browsing on web-building spiders that inhabit the understory vegetation varied with feeding guild. Deer tended to affect web-invading spiders, which inhabit the webs of other spiders and steal prey, more heavily than other web-building spiders, probably because of the accumulated effects of habitat fragmentation through the trophic levels. Thus, the treatment of a particular higher-order taxon as a homogeneous group could result in misleading conclusions about the effects of mammalian herbivores. PMID:18801259

  13. Disgust and disgust sensitivity in spider phobia : Facial EMG in response to spider and oral disgust imagery

    NARCIS (Netherlands)

    de Jong, Peter; Peters, Madelon L.; Vanderhallen, [Unknown

    2002-01-01

    Increasing evidence suggests that disgust and fear of contamination is involved in spider phobia. Yet, because the evidence exclusively relies on self-report data it can not be ruled out these findings are produced by mechanisms such as a negative attribution bias, or imprecise emotional labeling. T

  14. Black Holes

    Science.gov (United States)

    Luminet, Jean-Pierre

    1992-09-01

    Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.

  15. Loss of legs: is it or not a handicap for an orb-weaving spider?

    Science.gov (United States)

    Pasquet, Alain; Anotaux, Mylène; Leborgne, Raymond

    2011-07-01

    Leg loss is a common phenomenon in spiders, and according to the species 5% to 40% of the adults can present at least one missing leg. There is no possibility of regeneration after adult moult and the animal must manage with its missing appendages until its death. With the loss of one or more legs, female orb-weaving spiders can be penalized twice: firstly, because the legs are necessary for web construction and secondly, the legs are essential for the control of the prey after its interception by the web. During development, spiders may be also penalized because regeneration has energetic costs that take away resources for survival, growth and reproduction. All these consequences should influence negatively the development of the spider and thus its fitness. We investigated the impact of leg loss in the orb-weaving spider, Zygiella x-notata by studying its frequency in a natural population and web building and prey capture behaviours in laboratory. In field populations, 9.5% to 13%, of the adult females presented the loss of one or more legs; the majority of individuals had lost only one leg (in 48% of cases, a first one). Leg loss seems to affect all the adult spiders, as there is no difference of mass between intact spiders and those with missing leg. Data obtained with laboratory-reared spiders, showed that the loss of legs due to the moult is rare (less than 1%). Considering changes in web design, spiders with missing legs decreased their silk investment, increased the distance between spiral turns but did not change the capture surface of the web. Under our laboratory experimental conditions, spiders with one or two lost legs did not present any difference in prey capture efficiency. In laboratory conditions, spiders with lost leg(s) did not show any difference in egg sac production or in longevity (adult lifespan) compared to intact spiders.

  16. 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. PMID:17091284

  17. The Role of Silk in the Behaviour and Sociality of Spiders

    OpenAIRE

    Bertrand Krafft; Cookson, Laurie J.

    2012-01-01

    This article describes the links between the production of silk by spiders and their behaviour. Silk allows the spider to change its physical environment, which in turn leads to behavioural changes and impacts in the new environment. The feedback between silk and the animal producer can explain the architecture of spider webs and their adaptation to the environment, by referring only to stereotypic stimulus-response reactions without necessarily resorting to a “representation” by the animal o...

  18. fMRI neurofeedback facilitates anxiety regulation in females with spider phobia

    OpenAIRE

    Anna eZilverstand; Bettina eSorger; Pegah eSarkheil; Rainer eGoebel

    2015-01-01

    Background: Spider phobics show an exaggerated fear response when encountering spiders. This fear response is aggravated by negative and irrational beliefs about the feared object. Cognitive reappraisal can target these beliefs, and therefore has a fear regulating effect. The presented study investigated if neurofeedback derived from functional magnetic resonance imaging (fMRI) would facilitate anxiety regulation by cognitive reappraisal, using spider phobia as a model of anxiety disorders. F...

  19. High school students' attitudes towards spiders: a cross-cultural comparison

    OpenAIRE

    Prokop, Pavol; Tolarovičová, Andrea; Camerik, Anne M; Peterková, Viera

    2010-01-01

    Abstract 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, however, ambivalent. Using a five-point score Likert-type questionnaire in which the items were developed in a similar way to f...

  20. A spider that feeds indirectly on vertebrate blood by choosing female mosquitoes as prey

    OpenAIRE

    Robert R. Jackson; Nelson, Ximena J.; Sune, Godfrey O.

    2005-01-01

    Spiders do not feed directly on vertebrate blood, but a small East African jumping spider (Salticidae), Evarcha culicivora, feeds indirectly on vertebrate blood by choosing as preferred prey female mosquitoes that have had recent blood meals. Experiments show that this spider can identify its preferred prey by sight alone and by odor alone. When presented with two types of size-matched motionless lures, E. culicivora consistently chose blood-fed female mosquitoes in preference to nonmosquito ...

  1. Prediction of abundance of forest spiders according to climate warming in South Korea

    OpenAIRE

    Tae-Sung Kwon; Cheol Min Lee; Tae Woo Kim; Sung-Soo Kim; Joo Han Sung

    2014-01-01

    Distribution of spiders will be changed as climate warms. Abundance of spider species was predicted nationwide in South Korea. Abundance of spiders was projected using temperature species distribution model based on a nationwide data (366 forest sites) according to climate change scenario RCP 4.5 and 8.5. The model predicts that 9 out of 17 species will increase in abundance while 8 species will decrease. Based on this finding, a qualitative prediction (increase or decrease) was conducted on ...

  2. Ubiquitous distribution of salts and proteins in spider glue enhances spider silk adhesion

    Science.gov (United States)

    Amarpuri, Gaurav; Chaurasia, Vishal; Jain, Dharamdeep; Blackledge, Todd A.; Dhinojwala, Ali

    2015-03-01

    Modern orb-weaving spiders use micron-sized glue droplets on their viscid silk to retain prey in webs. A combination of low molecular weight salts and proteins makes the glue viscoelastic and humidity responsive in a way not easily achieved by synthetic adhesives. Optically, the glue droplet shows a heterogeneous structure, but the spatial arrangement of its chemical components is poorly understood. Here, we use optical and confocal Raman microscopy to show that salts and proteins are present ubiquitously throughout the droplet. The distribution of adhesive proteins in the peripheral region explains the superior prey capture performance of orb webs as it enables the entire surface area of the glue droplet to act as a site for prey capture. The presence of salts throughout the droplet explains the recent Solid-State NMR results that show salts directly facilitate protein mobility. Understanding the function of individual glue components and the role of the droplet's macro-structure can help in designing better synthetic adhesives for humid environments.

  3. Spatial distribution of Madeira Island Laurisilva endemic spiders (Arachnida: Araneae

    Directory of Open Access Journals (Sweden)

    Luís Crespo

    2014-02-01

    Full Text Available Madeira island presents a unique spider diversity with a high number of endemic species, many of which are still poorly known. A recent biodiversity survey on the terrestrial arthropods of the native forest, Laurisilva, provided a large set of standardized samples from various patches throughout the island. Out of the fifty two species recorded, approximately 33.3% are Madeiran endemics, many of which had not been collected since their original description. Two new species to science are reported – Ceratinopsis n. sp. and Theridion n. sp. – and the first records of Poeciloneta variegata (Blackwall, 1841 and Tetragnatha intermedia Kulczynski, 1891 are reported for the first time for Madeira island. Considerations on species richness and abundance from different Laurisilva locations are presented, together with distribution maps for endemic species. These results contribute to a better understanding of spider diversity patterns and endemic species distribution in the native forest of Madeira island.

  4. Environmental Engineering Approaches toward Sustainable Management of Spider Mites

    Directory of Open Access Journals (Sweden)

    Takeshi Suzuki

    2012-10-01

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

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

    Science.gov (United States)

    Suzuki, Takeshi

    2012-01-01

    Integrated pest management (IPM), which combines physical, biological, and chemical control measures to complementary effect, is one of the most important approaches to environmentally friendly sustainable agriculture. To expand IPM, we need to develop new pest control measures, reinforce existing measures, and investigate interactions between measures. Continued progress in the development of environmental control technologies and consequent price drops have facilitated their integration into plant production and pest control. Here I describe environmental control technologies for the IPM of spider mites through: (1) the disturbance of photoperiod-dependent diapause by artificial light, which may lead to death in seasonal environments; (2) the use of ultraviolet radiation to kill or repel mites; and (3) the use of water vapor control for the long-term cold storage of commercially available natural enemies. Such environmental control technologies have great potential for the efficient control of spider mites through direct physical effects and indirect effects via natural enemies. PMID:26466730

  6. Hamiltonian Dynamics of Spider-Type Multirotor Rigid Bodies Systems

    International Nuclear Information System (INIS)

    This paper sets out to develop a spider-type multiple-rotor system which can be used for attitude control of spacecraft. The multirotor system contains a large number of rotor-equipped rays, so it was called a 'Spider-type System', also it can be called 'Rotary Hedgehog'. These systems allow using spinups and captures of conjugate rotors to perform compound attitude motion of spacecraft. The paper describes a new method of spacecraft attitude reorientation and new mathematical model of motion in Hamilton form. Hamiltonian dynamics of the system is investigated with the help of Andoyer-Deprit canonical variables. These variables allow obtaining exact solution for hetero- and homoclinic orbits in phase space of the system motion, which are very important for qualitative analysis.

  7. 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

  8. Diffraction from the beta-sheet crystallites in spider silk.

    Science.gov (United States)

    Ulrich, S; Glišović, A; Salditt, T; Zippelius, A

    2008-11-01

    We analyze the wide-angle X-ray scattering from oriented spider silk fibers in terms of a quantitative scattering model, including both structural and statistical parameters of the beta-sheet crystallites of spider silk in the amorphous matrix. The model is based on kinematic scattering theory and allows for rather general correlations of the positional and orientational degrees of freedom, including the crystallite's size, composition and dimension of the unit cell. The model is evaluated numerically and compared to experimental scattering intensities allowing us to extract the geometric and statistical parameters. We show explicitly that for the experimentally found mosaicity (width of the orientational distribution) intercrystallite effects are negligible and the data can be analyzed in terms of single-crystallite scattering, as is usually assumed in the literature. PMID:18843512

  9. Black Culture

    Directory of Open Access Journals (Sweden)

    Angela Khristin Brown

    2013-07-01

    Full Text Available The migration of blacks in North America through slavery became united.  The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life. 

  10. Spiders (Araneae) as polyphagous natural enemies in orchards

    OpenAIRE

    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 and behaviour found in different species of one family can be seen as characteristic for the whole family. Especially in orchards little is known about their role and probably it is undervalued. The...

  11. 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.

  12. Spiders in mountain habitats of the Giant Mountains

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil; Vaněk, J.; Šmilauer, P.

    2012-01-01

    Roč. 43, č. 4 (2012), s. 341-347. ISSN 1067-4136 Institutional research plan: CEZ:AV0Z50070508 Keywords : Giant Mountains (Krkonoše, Karkonosze) * spiders * anemo-orographic systems Subject RIV: EH - Ecology, Behaviour Impact factor: 0.236, year: 2012 http://www.springerlink.com/content/0k5g721q1155r146/fulltext.pdf

  13. Colonization of subterranean habitats by spiders in Central Europe

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil; Šmilauer, P.; Mlejnek, R.

    2013-01-01

    Roč. 42, č. 2 (2013), s. 133-140. ISSN 0392-6672 Grant ostatní: GA JU(CZ) GAJU 04-142/2010/P Institutional support: RVO:60077344 Keywords : superficial and deep subterranean habitats * caves * spiders Subject RIV: EH - Ecology, Behaviour Impact factor: 1.275, year: 2013 http://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=1288&context=ijs

  14. Evidence for competition between carnivorous plants and spiders

    OpenAIRE

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

    2010-01-01

    Several studies have demonstrated that competition between disparate taxa can be important in determining community structure, yet surprisingly, to our knowledge, no quantitative studies have been conducted on competition between carnivorous plants and animals. To examine potential competition between these taxa, we studied dietary and microhabitat overlap between pink sundews (Drosera capillaris) and wolf spiders (Lycosidae) in the field, and conducted a laboratory experiment examining the e...

  15. Synthetic Spider Silk Production on a Laboratory Scale

    OpenAIRE

    Hsia, Yang; Gnesa, Eric; Pacheco, Ryan; Kohler, Kristin; Jeffery, Felicia; Vierra, Craig

    2012-01-01

    As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation biomaterials with high performance properties. The development of these new structural materials must be rapid, cost-efficient and involve processing methodologies and products that are environmentally friendly and sustainable. Spiders spin a multitude of different fiber types with diverse mechanical properties, offering a rich source of next ge...

  16. The deep phylogeny of jumping spiders (Araneae, Salticidae)

    OpenAIRE

    Wayne Maddison; Daiqin Li; Melissa Bodner; Junxia Zhang; Xu Xin; Qinqing Liu; Fengxiang Liu

    2014-01-01

    In order to resolve better the deep relationships among salticid spiders, we compiled and analyzed a molecular dataset of 169 salticid taxa (and 7 outgroups) and 8 gene regions. This dataset adds many new taxa to previous analyses, especially among the non-salticoid salticids, as well as two new genes – wingless and myosin heavy chain. Both of these genes, and especially the better sampled wingless, confirm many of the relationships indicated by other genes. The cocalodines are placed a...

  17. ArachnoServer: a database of protein toxins from spiders

    OpenAIRE

    Kaas Quentin; Raven Robert J; Cai Shuzhi; Miljenović Tomas; Wood David LA; Escoubas Pierre; Herzig Volker; Wilson David; King Glenn F

    2009-01-01

    Abstract Background Venomous animals incapacitate their prey using complex venoms that can contain hundreds of unique protein toxins. The realisation that many of these toxins may have pharmaceutical and insecticidal potential due to their remarkable potency and selectivity against target receptors has led to an explosion in the number of new toxins being discovered and characterised. From an evolutionary perspective, spiders are the most successful venomous animals and they maintain by far t...

  18. Damage, Self-Healing, and Hysteresis in Spider Silks

    OpenAIRE

    De Tommasi, D.; Puglisi, G.; Saccomandi, G.

    2010-01-01

    In this article, we propose a microstructure-based continuum model to describe the material behavior of spider silks. We suppose that the material is composed of a soft fraction with entropic elasticity and a hard, damageable fraction. The hard fraction models the presence of stiffer, crystal-rich, oriented regions and accounts for the effect of softening induced by the breaking of hydrogen bonds. To describe the observed presence of crystals with different size, composition, and orientation,...

  19. Climate change and sexual size dimorphism in an Arctic spider

    OpenAIRE

    Høye, Toke Thomas; Hammel, Jörg U; Fuchs, Thomas; Toft, Søren

    2009-01-01

    Climate change is advancing the onset of the growing season and this is happening at a particularly fast rate in the High Arctic. However, in most species the relative fitness implications for males and females remain elusive. Here, we present data on 10 successive cohorts of the wolf spider Pardosa glacialis from Zackenberg in High-Arctic, northeast Greenland. We found marked inter-annual variation in adult body size (carapace width) and this variation was greater in females than in males. E...

  20. SPIDER diagnostics technique for Vulcan 10 PW OPCPA project

    Czech Academy of Sciences Publication Activity Database

    Divoký, Martin; Hernandez-Gomez, C.

    Swindon : Central Laser Facility, 2008, s. 273-275 R&D Projects: GA MŠk(CZ) LC528 Grant ostatní: LASERLAB-EUROPE(XE) RII3-CT-2003-506350 Institutional research plan: CEZ:AV0Z10100523 Keywords : spectral phase measurement * SPIDER * ultra-short pulse measurement Subject RIV: BH - Optics, Masers, Lasers http://www.clf.rl.ac.uk/reports/2007-2008/ lsd _vulcan.htm

  1. 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. PMID:27280416

  2. The use of spider webs as passive bioaerosol collectors

    Science.gov (United States)

    Mattei, Daniel I.; Bleckmann, Charles A.; Bunker, David J.; Maxis, Ike

    2009-05-01

    Spider webs were shown to be effective collectors of bioaerosols and airborne microorganisms. Spider webs were collected and analyzed for microbial content using two general microbial culture mediums. To be considered suitable passive collectors, webs had to satisfy three basic conditions; (1) collection of microorganisms without discrimination based on species or size, (2) collection under variable environmental conditions, and (3) saturation avoidance in the presence of strong microbial launching sources. Samples were collected from four locations near Wright-Patterson Air Force Base, OH, a waste water treatment facility, a commercial garden center, a secluded state park area, and a parking garage located within a medium size metropolitan area. These four locations provided appropriately varied environmental and physical conditions to test the collection parameters previously stated. A simple collection methodology was devised; microscopy cover glass slides were used as collection instruments. The methodology assured sterility during collection and permitted in situ microbial growth, observation, and enumeration. Microbial growth, both bacteria and fungi, were recovered from all collected spider web samples.

  3. Post-secretion processing influences spider silk performance.

    Science.gov (United States)

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

    2012-10-01

    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

  4. Detail design of the beam source for the SPIDER experiment

    Energy Technology Data Exchange (ETDEWEB)

    Marcuzzi, D. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Agostinetti, P., E-mail: piero.agostinetti@igi.cnr.i [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Dalla Palma, M.; Degli Agostini, F.; Pavei, M.; Rizzolo, A.; Tollin, M.; Trevisan, L. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy)

    2010-12-15

    The ITER Neutral Beam Test Facility (PRIMA-Padova Research on Injector Megavolt Accelerated) is planned to be built at Consorzio RFX (Padova, Italy). PRIMA includes two experimental devices: a full size plasma source with low voltage extraction called SPIDER (Source for Production of Ion of Deuterium Extracted from RF plasma) and a full size neutral beam injector at full beam power called MITICA (Megavolt ITER Injector Concept Advancement). SPIDER is the first experimental device to be built and operated, aiming at testing the extraction of a negative ion beam (made of H{sup -} and in a later stage D{sup -} ions) from an ITER size ion source. The main requirements of this experiment are a H{sup -}/D{sup -} current of approximately 70 A/50 A and an energy of 100 keV. This paper presents an overview of the SPIDER beam source design, with a particular focus on the main design choices, aiming at reaching the best compromise between physics, optics, thermo-mechanical, cooling, assembly and electrical requirements.

  5. Seasonal variation of ground spiders in a Brazilian Savanna

    Directory of Open Access Journals (Sweden)

    Marina Farcic Mineo

    2010-06-01

    Full Text Available The Brazilian Savanna Ecoregion (Cerrado is one of the richest biomes in the world, with a characteristic highly seasonal climate a dry season between May and September and a rainy season from October through April. Ground-dwelling spiders from three Cerrado phytophysiognomies, "campo cerrado", "cerrado" and "cerrad��o", were sampled using pitfall traps during two years, totaling 111 species and 3,529 individuals. The abundance of individuals and species richness was higher during the wet season. Fifty-eight species were captured exclusively during that period, whereas only nineteen were restricted to the dry season. Only two species were found in all samples. The number of juveniles was higher than the number of adults in all phytophysiognomies and in all species during both seasons. The highest abundance was registered in October and the lowest in April. Overall sex ratio was male-biased in all vegetation types sampled. Distinct climate variables affected the abundance of spiders depending on sex, age and vegetal physiognomy where they were sampled. This study involved the longest sampling of spider abundance and diversity on the ground of a Brazilian Savanna.

  6. Spider Optimization II: Optical, Magnetic and Foreground Effects

    CERN Document Server

    O'Dea, D T; Amiri, M; Benton, S J; Bock, J J; Bond, J R; Bonetti, J A; Bryan, S; Burger, B; Chiang, H C; Clark, C N; Contaldi, C R; Crill, B P; Davis, G; Dore, O; Farhang, M; Filippini, J P; Fissel, L M; Fraisse, A A; Gandilo, N N; Golwala, S; Gudmundsson, J E; Hasselfield, M; Hilton, G; Holmes, W; Hristov, V V; Irwin, K; Jones, W C; Kuo, C L; MacTavish, C J; Mason, P V; Montroy, T E; Morford, T A; Netterfield, C B; Rahlin, A S; Reintsema, C; 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; Wiebe, D

    2011-01-01

    Spider is a balloon-borne instrument designed to map the polarization of the cosmic microwave background (CMB) with degree-scale resolution over a large fraction of the sky. Spider's main goal is to measure the amplitude of primordial gravitational waves through their imprint on the polarization of the CMB if the tensor-to-scalar ratio, r, is greater than 0.03. To achieve this goal, instrumental systematic errors must be controlled with unprecedented accuracy. Here, we build on previous work to use simulations of Spider observations to examine the impact of several systematic effects that have been characterized through testing and modeling of various instrument components. In particular, we investigate the impact of the non-ideal spectral response of the half-wave plates, coupling between focal plane components and the Earth's magnetic field, and beam mismatches and asymmetries. We also present a model of diffuse polarized foreground emission based on a three-dimensional model of the Galactic magnetic field ...

  7. Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds

    Science.gov (United States)

    Walters, D.M.; Mills, M.A.; Fritz, K.M.; Raikow, D.F.

    2010-01-01

    We investigated aquatic insect utilization and PCB exposure in riparian spiders at the Lake Hartwell Superfund site (Clemson, SC). We sampled sediments, adult chironomids, terrestrial insects, riparian spiders (Tetragnathidae, Araneidae, and Mecynogea lemniscata), and upland spiders (Araneidae) along a sediment contamination gradient. Stable isotopes (?13C, ? 15N) indicated that riparian spiders primarily consumed aquatic insects whereas upland spiders consumed terrestrial insects. PCBs in chironomids (mean 1240 ng/g among sites) were 2 orders of magnitude higher than terrestrial insects (15.2 ng/g), similar to differences between riparian (820?2012 ng/g) and upland spiders (30 ng/g). Riparian spider PCBs were positively correlated with sediment concentrations for all taxa (r2 = 0.44?0.87). We calculated spider-based wildlife values (WVs, the minimum spider PCB concentrations causing physiologically significant doses in consumers) to assess exposure risks for arachnivorous birds. Spider concentrations exceeded WVs for most birds at heavily contaminated sites and were ?14-fold higher for the most sensitive species (chickadee nestlings, Poecile spp.). Spiders are abundant and ubiquitous in riparian habitats, where they depend on aquatic insect prey. These traits, along with the high degree of spatial correlation between spider and sediment concentrations we observed, suggest that they are model indicator species for monitoring contaminated sediment sites and assessing risks associated with contaminant flux into terrestrial ecosystems. ?? This article not subject to U.S. Copyright. Published 2009 by the American Chemical Society.

  8. Are black holes totally black?

    CERN Document Server

    Grib, A A

    2014-01-01

    Geodesic completeness needs existence near the horizon of the black hole of "white hole" geodesics coming from the region inside of the horizon. Here we give the classification of all such geodesics with the energies $E/m \\le 1$ for the Schwarzschild and Kerr's black hole. The collisions of particles moving along the "white hole" geodesics with those moving along "black hole" geodesics are considered. Formulas for the increase of the energy of collision in the centre of mass frame are obtained and the possibility of observation of high energy particles arriving from the black hole to the Earth is discussed.

  9. 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

  10. Sperm dynamics in spiders (Araneae: ultrastructural analysis of the sperm activation process in the garden spider Argiope bruennichi (Scopoli, 1772.

    Directory of Open Access Journals (Sweden)

    Oliver Vöcking

    Full Text Available 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 are surrounded by a proteinaceous sheath. These inactive and encapsulated sperm are transferred to the female spermathecae where they are stored for later fertilization. We analyzed the ultrastructural changes of sperm cells during residency time in the female genital system of the orb-web spider Argiope bruennichi. We found three clearly distinguishable sperm conditions: encapsulated sperm (secretion sheath present, decapsulated (secretion sheath absent and uncoiled sperm (cell components uncoiled, presumably activated. After insemination, sperm remain in the encapsulated condition for several days and become decapsulated after variable periods of time. A variable portion of the decapsulated sperm transforms rapidly to the uncoiled condition resulting in a simultaneous occurrence of decapsulated and uncoiled sperm. After oviposition, only decapsulated and uncoiled sperm are left in the spermathecae, strongly suggesting that the activation process is not reversible. Furthermore, we found four different types of secretion in the spermathecae which might play a role in the decapsulation and activation process.

  11. Sperm dynamics in spiders (Araneae): ultrastructural analysis of the sperm activation process in the garden spider Argiope bruennichi (Scopoli, 1772).

    Science.gov (United States)

    Vöcking, Oliver; Uhl, Gabriele; Michalik, Peter

    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 are surrounded by a proteinaceous sheath. These inactive and encapsulated sperm are transferred to the female spermathecae where they are stored for later fertilization. We analyzed the ultrastructural changes of sperm cells during residency time in the female genital system of the orb-web spider Argiope bruennichi. We found three clearly distinguishable sperm conditions: encapsulated sperm (secretion sheath present), decapsulated (secretion sheath absent) and uncoiled sperm (cell components uncoiled, presumably activated). After insemination, sperm remain in the encapsulated condition for several days and become decapsulated after variable periods of time. A variable portion of the decapsulated sperm transforms rapidly to the uncoiled condition resulting in a simultaneous occurrence of decapsulated and uncoiled sperm. After oviposition, only decapsulated and uncoiled sperm are left in the spermathecae, strongly suggesting that the activation process is not reversible. Furthermore, we found four different types of secretion in the spermathecae which might play a role in the decapsulation and activation process. PMID:24039790

  12. Neural correlation of successful cognitive behaviour therapy for spider phobia: a magnetoencephalography study.

    Science.gov (United States)

    Wright, Barry; Alderson-Day, Ben; Prendergast, Garreth; Kennedy, Juliette; Bennett, Sophie; Docherty, Mary; Whitton, Clare; Manea, Laura; Gouws, Andre; Tomlinson, Heather; Green, Gary

    2013-12-30

    Cognitive behavioural therapy (CBT) can be an effective treatment for spider phobia, but the underlying neural correlates of therapeutic change are yet to be specified. The present study used magnetoencephalography (MEG) to study responses within the first half second, to phobogenic stimuli in a group of individuals with spider phobia prior to treatment (n=12) and then in nine of them following successful CBT (where they could touch and manage live large common house spiders) at least 9 months later. We also compared responses to a group of age-matched healthy control participants (n=11). Participants viewed static photographs of real spiders, other fear-inducing images (e.g. snakes, sharks) and neutral stimuli (e.g. kittens). Beamforming methods were used to localise sources of significant power changes in response to stimuli. Prior to treatment, participants with spider phobia showed a significant maximum response in the right frontal pole when viewing images of real spiders specifically. No significant frontal response was observed for either control participants or participants with spider phobia post-treatment. In addition, participants' subjective ratings of spider stimuli significantly predicted peak responses in right frontal regions. The implications for understanding brain-based effects of cognitive therapies are discussed. PMID:24139305

  13. Utility Assessment Report for SPIDERS Phase 2: Ft. Carson (Rev 1.0)

    Energy Technology Data Exchange (ETDEWEB)

    Barr, Jonathan L.; Tuffner, Francis K.; Hadley, Mark D.; Schneider, Kevin P.

    2014-01-01

    This document contains the Utility Assessment Report (UAR) for the Phase 2 operational Demonstration (OD) of the Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS) Joint Capability Technology Demonstration (JCTD). The UAR for Phase 2 shows that the SPIDERS system was able to meet the requirements of the Implementation Directive at Ft. Carson.

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

    NARCIS (Netherlands)

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

    2003-01-01

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

  15. Plant effects on biological control of spider mites in the ornamental crop Gerbera

    NARCIS (Netherlands)

    Krips, O.E.

    2000-01-01

    IntroductionThe spider mite Tetranychus urticae Koch is an important pest in many greenhouse crops. In vegetables it can be successfully controlled with the predatory mite Phytoseiulus persimilis Athias-Henriot, a specialist predator of spider mites (Helle & Sabelis, 1985). However,

  16. A New Spin on Miscue Analysis: Using Spider Charts to Web Reading Processes

    Science.gov (United States)

    Wohlwend, Karen E.

    2012-01-01

    This article introduces a way of seeing miscue analysis data through a "spider chart", a readily available digital graphing tool that provides an effective way to visually represent readers' complex coordination of interrelated cueing systems. A spider chart is a standard feature in recent spreadsheet software that puts a new spin on miscue…

  17. Compositional changes in spider (Araneae) assemblages along an urbanisation gradient near a Danish town

    DEFF Research Database (Denmark)

    Horváth, R.; Elek, Zoltán; Lövei, Gabor L

    2014-01-01

    species, with money spiders (Linyphiidae) and wolf spiders (Lycosidae) being most numerous. One species, Ero aphana, was new to the Danish fauna. In 2004, 45-47 species were captured in the habitats in various stages of urbanisation, while in 2005 (with a smaller collection effort), 28 (urban) - 37 (rural...

  18. Unidirectional and transitive predatory relationships of spider species in one-on-one encounters (Arachnida; Araneae)

    NARCIS (Netherlands)

    T.M. Brunt; B.A. Heuts

    2008-01-01

    Inter-specific predation (‘inter-specific araneophagy’) among spiders is very common in the field. We investigated the transitivity (defined hereafter) of inter-specific predatory dominance relationships among 60 spider species belonging to 16 families in the laboratory in one-on-one encounters betw

  19. High School Students' Attitudes Towards Spiders: A cross-cultural comparison

    Science.gov (United States)

    Prokop, Pavol; Tolarovičová, Andrea; Camerik, Anne M.; Peterková, Viera

    2010-08-01

    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, however, ambivalent. Using a five-point score Likert-type questionnaire in which the items were developed in a similar way to four of Kellert's categories of attitude (scientistic, negativistic, naturalistic, and ecologistic) towards invertebrates, we compared the level of knowledge of and attitudes towards spiders of high school students from two countries, Slovakia (n = 354) and South Africa (n = 382). The students represented different cultures and followed dissimilar science education curricula. Only among the Slovakian students there was a statistically significant but low correlation between knowledge and attitude (r = 0.30). The South African students scored higher in the categories of scientistic, naturalistic, and ecologistic attitudes. Comparison of attitude towards spiders of indigenous Africans from coeducational Catholic schools revealed that South African students have greater fear of spiders than Slovakian students, supporting the biological preparedness hypothesis. This hypothesis predicts a greater fear of spiders in South Africa than in Europe since several South African spiders possess venoms that are dangerous to humans. The results of this study are discussed from science education, cultural, and evolutionary perspectives.

  20. Counterconditioning in the treatment of spider phobia : effects on disgust, fear and valence

    NARCIS (Netherlands)

    de Jong, Peter; Vorage, [Unknown; van den Hout, MA

    2000-01-01

    From the perspective that disgust is a core feature of spider phobia, we investigated whether the treatment efficacy could be improved by adding a counterconditioning procedure. Women with a clinically diagnosed spider phobia (N = 34) were randomly assigned to the regular one-session exposure condit

  1. fMRI neurofeedback facilitates anxiety regulation in females with spider phobia

    NARCIS (Netherlands)

    Zilverstand, Anna; Sorger, Bettina; Sarkheil, Pegah; Goebel, R.

    2015-01-01

    BACKGROUND: Spider phobics show an exaggerated fear response when encountering spiders. This fear response is aggravated by negative and irrational beliefs about the feared object. Cognitive reappraisal can target these beliefs, and therefore has a fear regulating effect. The presented study investi

  2. Species richness and composition assessment of spiders in a Mediterranean scrubland

    DEFF Research Database (Denmark)

    Bondoso Cardoso, Pedro Miguel; Henriques, Sérgio S.; Gaspar, Clara;

    2009-01-01

    Intensive fieldwork has been undertaken in Portugal in order to develop a standardized and optimized sampling protocol for Mediterranean spiders. The present study had the objectives of testing the use of semi-quantitative sampling for obtaining an exhaustive species richness assessment of spider...

  3. Periumbilical Pain with Radiation to Both Legs Following Tarantula Bite; a Case Report

    Directory of Open Access Journals (Sweden)

    Mahboob Pouraghaei

    2015-07-01

    Full Text Available Tarantulas have recently become as pets in most parts of the world that increased the probability of encountering emergency physicians with patients hurt with these spiders. Their attacks usually do not cause general manifestation, however there are some case reports in this regard. Here, a 40-year-old man was reported who was referred to the emergency department with severe periumbilical pain that radiated to both legs and diagnosed as a victim of tarantula bite. Such symptoms usually are belonging to other spiders like Black Widow spider, but it seems that tarantula can mimic them in some cases, too.

  4. Periumbilical Pain with Radiation to Both Legs Following Tarantula Bite; a Case Report.

    Science.gov (United States)

    Pouraghaei, Mahboob; Shams Vahdati, Samad; Mashhadi, Ibrahim; Mahmoudieh, Taranoom

    2015-01-01

    Tarantulas have recently become as pets in most parts of the world that increased the probability of encountering emergency physicians with patients hurt with these spiders. Their attacks usually do not cause general manifestation, however there are some case reports in this regard. Here, a 40-year-old man was reported who was referred to the emergency department with severe periumbilical pain that radiated to both legs and diagnosed as a victim of tarantula bite. Such symptoms usually are belonging to other spiders like Black Widow spider, but it seems that tarantula can mimic them in some cases, too. PMID:26495398

  5. Factors that influence the beta-diversity of spider communities in northwestern Argentinean Grasslands.

    Science.gov (United States)

    Rodriguez-Artigas, Sandra M; Ballester, Rodrigo; Corronca, Jose A

    2016-01-01

    Beta-diversity, defined as spatial replacement in species composition, is crucial to the understanding of how local communities assemble. These changes can be driven by environmental or geographic factors (such as geographic distance), or a combination of the two. Spiders have been shown to be good indicators of environmental quality. Accordingly, spiders are used in this work as model taxa to establish whether there is a decrease in community similarity that corresponds to geographic distance in the grasslands of the Campos & Malezales ecoregion (Corrientes). Furthermore, the influence of climactic factors and local vegetation heterogeneity (environmental factors) on assemblage composition was evaluated. Finally, this study evaluated whether the differential dispersal capacity of spider families is a factor that influences their community structure at a regional scale. Spiders were collected with a G-Vac from vegetation in six grassland sites in the Campos & Malezales ecoregion that were separated by a minimum of 13 km. With this data, the impact of alpha-diversity and different environmental variables on the beta-diversity of spider communities was analysed. Likewise, the importance of species replacement and nesting on beta-diversity and their contribution to the regional diversity of spider families with different dispersion capacities was evaluated. The regional and site-specific inventories obtained were complete. The similarity between spider communities declined as the geographic distance between sites increased. Environmental variables also influenced community composition; stochastic events and abiotic forces were the principal intervening factors in assembly structure. The differential dispersal capacity of spider groups also influenced community structure at a regional scale. The regional beta-diversity, as well as species replacement, was greater in high and intermediate vagility spiders; while nesting was greater in spiders with low dispersion

  6. Factors that influence the beta-diversity of spider communities in northwestern Argentinean Grasslands

    Science.gov (United States)

    Rodriguez-Artigas, Sandra M.; Ballester, Rodrigo

    2016-01-01

    Beta-diversity, defined as spatial replacement in species composition, is crucial to the understanding of how local communities assemble. These changes can be driven by environmental or geographic factors (such as geographic distance), or a combination of the two. Spiders have been shown to be good indicators of environmental quality. Accordingly, spiders are used in this work as model taxa to establish whether there is a decrease in community similarity that corresponds to geographic distance in the grasslands of the Campos & Malezales ecoregion (Corrientes). Furthermore, the influence of climactic factors and local vegetation heterogeneity (environmental factors) on assemblage composition was evaluated. Finally, this study evaluated whether the differential dispersal capacity of spider families is a factor that influences their community structure at a regional scale. Spiders were collected with a G-Vac from vegetation in six grassland sites in the Campos & Malezales ecoregion that were separated by a minimum of 13 km. With this data, the impact of alpha-diversity and different environmental variables on the beta-diversity of spider communities was analysed. Likewise, the importance of species replacement and nesting on beta-diversity and their contribution to the regional diversity of spider families with different dispersion capacities was evaluated. The regional and site-specific inventories obtained were complete. The similarity between spider communities declined as the geographic distance between sites increased. Environmental variables also influenced community composition; stochastic events and abiotic forces were the principal intervening factors in assembly structure. The differential dispersal capacity of spider groups also influenced community structure at a regional scale. The regional beta-diversity, as well as species replacement, was greater in high and intermediate vagility spiders; while nesting was greater in spiders with low dispersion

  7. Association of spiders and lichen on Robben Island, South Africa: a case report

    Directory of Open Access Journals (Sweden)

    A. Mukherjee

    2010-04-01

    Full Text Available The present study is a firstrecord of spider occurrence on Robben Island, South Africa. Some habitats were rich in lichens. As we know, lichens enhance wildlife habitat in less direct ways. The objective of the study was to examine the potential importance of lichens in enriching spider diversity and abundance. A total of 260 spiders (170 from lichens and 90 from bush were collected following the visual search method over one year. Seasonal trends in overall species richness and abundance indicated that the relative density of spiders was greater in lichens than in bushes. The result suggests that habitat structure, such as branch size and epiphytic lichen abundance, can be an explanation for the greater number of spiders in lichen-rich patches of the island.

  8. The time course of location-avoidance learning in fear of spiders.

    Science.gov (United States)

    Rinck, Mike; Koene, Marieke; Telli, Sibel; Moerman-van den Brink, Wiltine; Verhoeven, Barbara; Becker, Eni S

    2016-01-01

    Two experiments were designed to study the time course of avoidance learning in spider fearfuls (SFs) under controlled experimental conditions. To achieve this, we employed an immersive virtual environment (IVE): While walking freely through a virtual art museum to search for specific paintings, the participants were exposed to virtual spiders. Unbeknown to the participants, only two of four museum rooms contained spiders, allowing for avoidance learning. Indeed, the more SF the participants were, the faster they learned to avoid the rooms that contained spiders (Experiment. 1), and within the first six trials, high fearfuls already developed a preference for starting their search task in rooms without spiders (Experiment 2). These results illustrate the time course of avoidance learning in SFs, and they speak to the usefulness of IVEs in fundamental anxiety research. PMID:25707541

  9. Species composition and relative seasonal abundance of spiders from the field and tree layers of the Roodeplaat Dam Nature Reserve

    Directory of Open Access Journals (Sweden)

    Anna S. Dippenaar-Schoeman

    1989-10-01

    Full Text Available A survey of spiders was carried out at the Roodeplaat Dam Nature Reserve near Pretoria. Over a 4-year period 10 270 spiders were collected from grasses, herbs and trees. A total of 82 genera of spiders representing 27 families were recorded. Of all the spiders caught, 29,3 percent belonged to the Tetrag-nathidae, 22,7 percent to the Araneidae and 21,4 percent to the Salticidae. The proportion of spiders in each of the remaining 24 families did not exceed 6 percent of the total catch. The species composition and seasonal abundance are discussed.

  10. Trophic overlap between fish and riparian spiders: potential impacts of an invasive fish on terrestrial consumers.

    Science.gov (United States)

    Jackson, Michelle C; Woodford, Darragh J; Bellingan, Terence A; Weyl, Olaf L F; Potgieter, Michael J; Rivers-Moore, Nick A; Ellender, Bruce R; Fourie, Hermina E; Chimimba, Christian T

    2016-03-01

    Studies on resource sharing and partitioning generally consider species that occur in the same habitat. However, subsidies between linked habitats, such as streams and riparian zones, create potential for competition between populations which never directly interact. Evidence suggests that the abundance of riparian consumers declines after fish invasion and a subsequent increase in resource sharing of emerging insects. However, diet overlap has not been investigated. Here, we examine the trophic niche of native fish, invasive fish, and native spiders in South Africa using stable isotope analysis. We compared spider abundance and diet at upstream fishless and downstream fish sites and quantified niche overlap with invasive and native fish. Spider abundance was consistently higher at upstream fishless sites compared with paired downstream fish sites, suggesting that the fish reduced aquatic resource availability to riparian consumers. Spiders incorporated more aquatic than terrestrial insects in their diet, with aquatic insects accounting for 45-90% of spider mass. In three of four invaded trout rivers, we found that the average proportion of aquatic resources in web-building spider diet was higher at fishless sites compared to fish sites. The probability of web-building and ground spiders overlapping into the trophic niche of invasive brown and rainbow trout was as high as 26 and 51%, respectively. In contrast, the probability of spiders overlapping into the trophic niche of native fish was always less than 5%. Our results suggest that spiders share resources with invasive fish. In contrast, spiders had a low probability of trophic overlap with native fish indicating that the traits of invaders may be important in determining their influence on ecosystem subsidies. We have added to the growing body of evidence that invaders can have cross-ecosystem impacts and demonstrated that this can be due to niche overlap. PMID:27087934

  11. Climatic control of trophic interaction strength: the effect of lizards on spiders.

    Science.gov (United States)

    Spiller, David A; Schoener, Thomas W

    2008-01-01

    We investigated how temporal variation in rainfall influences the impact of lizards on spiders inhabiting small islands in Abaco, Bahamas. Annual censuses of web spiders were conducted on nine lizard islands and on eight no-lizard islands 1994-2003. Repeated-measures ANOVA showed that annual variation in spider density (time) and in the lizard effect on spider density (lizard x time) were both significant. Correlation coefficients between the lizard effect (ln ratio of no-lizard to lizard spider densities) and number of rainfall days were generally negative, and strengthened with length of the time period during which rainfall was measured prior to annual spider censuses. Spider density was also negatively correlated with rainfall days and strengthened with length of the prior time period. Longer time intervals included the hurricane season, suggesting that the strong negative correlations were linked to high rainfall years during which tropical storms impacted the region and reduced spider and lizard densities. Split-plot ANOVA showed that rainfall during the hurricane season had a significant effect on the lizard effect and on spider density. Results in this study are opposite to those found in our previous 10-year study (1981-1990) conducted in the Exuma Cays, a moderately xeric region of the Bahamas, where the relation between rainfall and the lizard effect on spider density was positive. Combined data from the Exuma and Abaco studies produce a unimodal relation between trophic interaction strength and rainfall; we suggest that the negative effect of storms associated with rainfall was paramount in the present study, whereas the positive bottom-up effect of rainfall prevailed in our previous study. We conclude that climatic variability has a major impact on the trophic interaction and suggest that a substantial change in precipitation in either direction may weaken the interaction significantly. PMID:17972107

  12. Structural color and its interaction with other color-producing elements: perspectives from spiders

    Science.gov (United States)

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

    2014-09-01

    Structural color is produced when nanostructures called schemochromes alter light reflected from a surface through different optic principles, in contrast with other types of colors that are produced when pigments selectively absorb certain wavelengths of light. Research on biogenic photonic nanostructures has focused primarily on bird feathers, butterfly wings and beetle elytra, ignoring other diverse groups such as spiders. We argue that spiders are a good model system to study the functions and evolution of colors in nature for the following reasons. First, these colors clearly function in spiders such as the tarantulas outside of sexual selection, which is likely the dominant driver of the evolution of structural colors in birds and butterflies. Second, within more than 44,000 currently known spider species, colors are used in every possible way based on the same sets of relatively simple materials. Using spiders, we can study how colors evolve to serve different functions under a variety of combinations of driving forces, and how those colors are produced within a relatively simple system. Here, we first review the different color-producing materials and mechanisms (i.e., light absorbing, reflecting and emitting) in birds, butterflies and beetles, the interactions between these different elements, and the functions of colors in different organisms. We then summarize the current state of knowledge of spider colors and compare it with that of birds and insects. We then raise questions including: 1. Could spiders use fluorescence as a mechanism to protect themselves from UV radiation, if they do not have the biosynthetic pathways to produce melanins? 2. What functions could color serve for nearly blind tarantulas? 3. Why are only multilayer nanostructures (thus far) found in spiders, while birds and butterflies use many diverse nanostructures? And, does this limit the diversity of structural colors found in spiders? Answering any of these questions in the future

  13. Black market

    International Nuclear Information System (INIS)

    One way for states and subnational groups to acquire material, knowledge and equipment necessary to build a nuclear weapon or device are illegal transactions. These were singular in the past and did not cause the development of a nuclear black market. But all necessary components of a functioning black market exist. Therefore the further spread and extension of the use of nuclear power would enhance the threat of a nuclear black market, if the trade and use of specific nuclear material is not abandoned worldwide. (orig.)

  14. Black tea

    Science.gov (United States)

    ... product containing black tea extract plus green tea extract, asparagus, guarana, kidney bean, and mate along with a combination of kidney bean pods, garcinia, and chromium yeast for 12 weeks does not reduce body weight ...

  15. SPIDERS Bi-Directional Charging Station Interconnection Testing

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, M.

    2013-09-01

    The Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS) program is a multi-year Department of Defense-Department of Energy (DOE) collaborative effort that will demonstrate integration of renewables into island-able microgrids using on-site generation control, demand response, and energy storage with robust security features at multiple installations. Fort Carson, Colorado, will be the initial development and demonstration site for use of plug-in electric vehicles as energy storage (also known as vehicle-to-grid or V2G).

  16. Design of a convertible drone from the Rolling Spider

    OpenAIRE

    Marí Marí, Marc

    2014-01-01

    [ANGLÈS] The Rolling Spider is Parrot's mini-quadcopter launched in summer 2014. Despite its very light design, this unmanned aerial vehicle has a great compactness and robustness and it has been mainly created for fun and model building fans. It is able to fly indoors and outdoors and it can be piloted via a smartphone or a tablet. Besides, it has an electronic embedded system working on Linux kernel and several sensors which aim at its stability during flight. Thus, the purpose of the proje...

  17. Heat Capacity of Spider Silk-like Block Copolymers

    OpenAIRE

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

    2011-01-01

    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 sta...

  18. Systemic lupus erythematosus flare triggered by a spider bite.

    Science.gov (United States)

    Martín Nares, Eduardo; López Iñiguez, Alvaro; Ontiveros Mercado, Heriberto

    2016-01-01

    Systemic lupus erythematosus is a chronic autoimmune disease with a relapsing and remitting course characterized by disease flares. Flares are a major cause of hospitalization, morbidity and mortality in patients with systemic lupus erythematosus. Some triggers for these exacerbations have been identified, including infections, vaccines, pregnancy, environmental factors such as weather, stress and drugs. We report a patient who presented with a lupus flare with predominantly mucocutaneous, serosal and cardiac involvement after being bitten by a spider and we present the possible mechanisms by which the venom elicited such a reaction. To the best of our knowledge, this is the first such case reported in the literature. PMID:26494589

  19. Structure and composition of the spider Argiope amoena egg case

    OpenAIRE

    Jiang, Ping; Xiao, Yong-Hong; Zhou, Bing; LIAO Xin-Jun; Guo, Cong

    2008-01-01

    The egg case of the spider A. amoena is composed of multiple layers of silk, including a frame of yellow silk, an outer cover with layers of gray-green, pale brown, and white silk, and an inner cover of brown silk. SEM shows the outer cover threads consist of six large diameter (4.8–6.8 µm) cylindrical gland monofilaments with numerous smaller diameter (0.26–0.76 µm) fibers. The number of small-diameter fibers varies with layer; it is high in outer layers and decreases in inner layers. Sma...

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

    Directory of Open Access Journals (Sweden)

    Yu Peng

    Full Text Available 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.

  1. 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. PMID:26308806

  2. Effects of kaolin particle films on the life span of an orb-weaver spider.

    Science.gov (United States)

    Benhadi-Marín, Jacinto; Pereira, José Alberto; Santos, Sónia A P

    2016-02-01

    Araniella cucurbitina (Araneae: Araneidae) is a widespread orb-weaver spider commonly found in agroecosystems. Mineral particle films such as kaolin, due to their protective or anti-feeding action, can represent an alternative to pesticides, especially in organic farming systems, but little is known about its effects on A. cucurbitina. Therefore, we tested the effect of kaolin sprays on the life span of A. cucurbitina under laboratory conditions. Four treatments were tested encompassing different exposure routes. Thus, kaolin sprays were applied on (i) the surface, (ii) the prey (fly), (iii) the spider and (iv) both spider & prey. A control group was tested with water in each treatment. Results showed that sprays of kaolin significantly affected the survival of A. curcubitina when applications were done on the surface and on both spider & prey registering a reduction of 48% and 56%, respectively. Spiders in control obtained higher probability of reaching alive at the end of the assay than those treated with kaolin. Differences observed can be explained by the feeding behavior of the species and may depend on the consumption of the web by the spider and the ratio spider/fly for body size. PMID:26432533

  3. The lethal toxin from Australian funnel-web spiders is encoded by an intronless gene.

    Directory of Open Access Journals (Sweden)

    Sandy Steffany Pineda

    Full Text Available Australian funnel-web spiders are generally considered the most dangerous spiders in the world, with envenomations from the Sydney funnel-web spider Atrax robustus resulting in at least 14 human fatalities prior to the introduction of an effective anti-venom in 1980. The clinical envenomation syndrome resulting from bites by Australian funnel-web spiders is due to a single 42-residue peptide known as δ-hexatoxin. This peptide delays the inactivation of voltage-gated sodium channels, which results in spontaneous repetitive firing and prolongation of action potentials, thereby causing massive neurotransmitter release from both somatic and autonomic nerve endings. Here we show that δ-hexatoxin from the Australian funnel-web spider Hadronyche versuta is produced from an intronless gene that encodes a prepropeptide that is post-translationally processed to yield the mature toxin. A limited sampling of genes encoding unrelated venom peptides from this spider indicated that they are all intronless. Thus, in distinct contrast to cone snails and scorpions, whose toxin genes contain introns, spiders may have developed a quite different genetic strategy for evolving their venom peptidome.

  4. Characterization of the complete mitogenomes of two Neoscona spiders (Araneae: Araneidae) and its phylogenetic implications.

    Science.gov (United States)

    Wang, Zheng-Liang; Li, Chao; Fang, Wen-Yuan; Yu, Xiao-Ping

    2016-09-30

    The complete mitogenomes of two orb-weaving spiders Neoscona doenitzi and Neoscona nautica were determined and a comparative mitogenomic analysis was performed to depict evolutionary trends of spider mitogenomes. The circular mitogenomes are 14,161bp with A+T content of 74.6% in N. doenitzi and 14,049bp with A+T content of 78.8% in N. nautica, respectively. Both mitogenomes contain a standard set of 37 genes typically presented in metazoans. Gene content and orientation are identical to all previously sequenced spider mitogenomes, while gene order is rearranged by tRNAs translocation when compared with the putative ancestral gene arrangement pattern presented by Limulus polyphemus. A comparative mitogenomic analysis reveals that the nucleotide composition bias is obviously divergent between spiders in suborder Opisthothelae and Mesothelae. The loss of D-arm in the trnS(UCN) among all of Opisthothelae spiders highly suggested that this common feature is a synapomorphy for entire suborder Opisthothelae. Moreover, the trnS(AGN) in araneoids preferred to use TCT as an anticodon rather than the typical anticodon GCT. Phylogenetic analysis based on the 13 protein-coding gene sequences consistently yields trees that nest the two Neoscona spiders within Araneidae and recover superfamily Araneoidea as a monophyletic group. The molecular information acquired from the results of this study should be very useful for future research on mitogenomic evolution and genetic diversities in spiders. PMID:27259661

  5. Interpretative bias in spider phobia: Perception and information processing of ambiguous schematic stimuli.

    Science.gov (United States)

    Haberkamp, Anke; Schmidt, Filipp

    2015-09-01

    This study investigates the interpretative bias in spider phobia with respect to rapid visuomotor processing. We compared perception, evaluation, and visuomotor processing of ambiguous schematic stimuli between spider-fearful and control participants. Stimuli were produced by gradually morphing schematic flowers into spiders. Participants rated these stimuli related to their perceptual appearance and to their feelings of valence, disgust, and arousal. Also, they responded to the same stimuli within a response priming paradigm that measures rapid motor activation. Spider-fearful individuals showed an interpretative bias (i.e., ambiguous stimuli were perceived as more similar to spiders) and rated spider-like stimuli as more unpleasant, disgusting, and arousing. However, we observed no differences between spider-fearful and control participants in priming effects for ambiguous stimuli. For non-ambiguous stimuli, we observed a similar enhancement for phobic pictures as has been reported previously for natural images. We discuss our findings with respect to the visual representation of morphed stimuli and to perceptual learning processes. PMID:26276153

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

    Science.gov (United States)

    Hénaut, Yann; Corbara, Bruno; Pélozuelo, Laurent; Azémar, Frédéric; Céréghino, Régis; Herault, Bruno; Dejean, Alain

    2014-01-01

    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. PMID:25494055

  7. 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.

  8. Exploration behaviour and behavioural flexibility in orb-web spiders: A review

    Institute of Scientific and Technical Information of China (English)

    Thomas HESSELBERG

    2015-01-01

    Orb-web spiders and their webs constitute an ideal model system in which to study behavioural flexibility and spatial cognition in invertebrates due to the easily quantifiable nature of the orb web.A large number of studies demonstrate how spiders are able to modify the geometry of their webs in response to a range of different conditions including the ability to adapt their webs to spatial constraints.However,the mechanisms behind this impressive web-building flexibility in these cognitively limited animals remain poorly explored.One possible mechanism though may be spatial learning during the spiders' exploration of their immediate surroundings.This review discusses the importance of exploration behaviour,the reliance on simple behavioural rules,and the use of already laid threads as guidelines for web-building in orb-web spiders.The focus is on the spiders' ability to detect and adapt their webs to space limitations and other spatial disruptions.I will also review the few published studies on how spatial information is gathered during the exploration phase and discuss the possibility of the use of ‘cognitive map’-like processes in spiders.Finally,the review provides suggestions for designing experimental studies to shed light on whether spiders gather metric information during the site exploration (cognitive map hypothesis) or rely on more simple binary information in combination with previously laid threads to build their webs (stigmergy hypothesis) [Current Zoology 61 (2):313-327,2015].

  9. The efficacy of treatment reminders of life with emphasis on integrative reminiscence on self-esteem and anxiety in widowed old men.

    Directory of Open Access Journals (Sweden)

    Malihe Pishvaei

    2015-03-01

    Full Text Available Loss of wife besides the phenomenon of aging could cause some psychological disorders and may shorten the duration of this stage of life. The aim of this study was to examine the efficacy of treatment reminders of life with emphasis on integrative reminiscence on self-esteem and anxiety in widowed old men.This was a clinical trial with pre-test and post-test design with a control group. The study population included All 60 to 80 year old men living in Meshginshahr; among whom, 34 participants were selected using convenience sampling method. They were randomly allocated into two equal groups (experimental and control. The experimental group participated in therapy sessions and the control group did not receive any intervention. The research instruments were Rosenberg Self-Esteem Scale and the General Anxiety Questionnaire. Data were analyzed using multivariable covariance analysis in SSPS-19. Statistical significance was set at P<0.05.MANCOVA results showed that the treatment positively affected the variables of self-esteem and anxiety in old widowed men (p<0.001.The reminders of life therapy with emphasis on integrative reminiscence may enhance self-esteem and reduce anxiety in widowed old men. This treatment gives better results compared to the traditional treatments and it is recommended to be implemented in nursing homes.

  10. Functional relations between locomotor performance traits in spiders and implications for evolutionary hypotheses

    Directory of Open Access Journals (Sweden)

    Taylor Phillip W

    2010-11-01

    Full Text Available Abstract Background Locomotor performance in ecologically relevant activities is often linked to individual fitness. Recent controversy over evolution of extreme sexual size dimorphism (SSD in spiders centres on the relationship between size and locomotor capacity in males. Advantages for large males running over horizontal surfaces and small males climbing vertically have been proposed. Models have implicitly treated running and climbing as functionally distinct activities and failed to consider the possibility that they reflect common underlying capacities. Findings We examine the relationship between maximum climbing and running performance in males of three spider species. Maximum running and climbing speeds were positively related in two orb-web spiders with high SSD (Argiope keyserlingi and Nephila plumipes, indicating that for these species assays of running and climbing largely reveal the same underlying capacities. Running and climbing speeds were not related in a jumping spider with low SSD (Jacksonoides queenslandica. We found no evidence of a performance trade-off between these activities. Conclusions In the web-spiders A. keyserlingi and N. plumipes good runners were also good climbers. This indicates that climbing and running largely represent a single locomotor performance characteristic in these spiders, but this was not the case for the jumping spider J. queenslandica. There was no evidence of a trade-off between maximum running and climbing speeds in these spiders. We highlight the need to establish the relationship between apparently disparate locomotor activities when testing alternative hypotheses that yield predictions about different locomotor activities. Analysis of slopes suggests greater potential for an evolutionary response on performance in the horizontal compared to vertical context in these spiders.

  11. Gender based structu[r]al violence in relation to the traditional practice of wife inheritance : the case of Malawi : an empirical study of the violence experienced by widows involved in wife inheritance practice

    OpenAIRE

    Tembo, Memory Jayne

    2013-01-01

    The purpose of the study is to investigate how gender based violence is enhanced through the practice of wife inheritance. This study is meant to describe and analyze the experience of widows who have undergone the practice of wife inheritance or were asked to follow this tradition. The study gathers the opinion of the widows, in regards to how they experienced the practice and whether they approved of the practice or not. The study also aims at exploring the different kinds of...

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

    DEFF Research Database (Denmark)

    Jensen, Kim; Mayntz, David; Toft, Søren;

    2011-01-01

    Nutrient balancing is well known in herbivores and omnivores, but has only recently been demonstrated in predators. To test how a predator might regulate nutrients when the prey varies in nutrient composition, we restricted juvenile Pardosa prativaga wolf spiders to diets of one of six fruit fly...... spiders were highly affected by the nutrient compositions of their prey, and growth in carapace length and lean body mass increased with increasing prey protein:lipid ratio. Our results demonstrate that prey nutrient composition affects these predators, but also that the spiders possess behavioural and...

  13. Stability of the volume of air trapped on the abdomen of the water spider Argyroneta aquatica

    OpenAIRE

    Neumann, Dietrich; Woermann, Dietrich

    2013-01-01

    The water spider Argyroneta aquatica lives under water, diving to various depths from time to time. At rest, it breathes air trapped within its diving bell with a hydrophilic surface. Outside their diving bell water spiders trap air on their abdomen under a layer of hydrophobic hair. Is the structure of the layer of hair trapping a volume of air on the abdomen of the water spider Argyroneta aquatica under water related to its observed diving depth (of the order of decimetre)? A positive answe...

  14. Adaptation of the spiders to the environment: the case of some Chilean species

    Science.gov (United States)

    Canals, Mauricio; Veloso, Claudio; Solís, Rigoberto

    2015-01-01

    Spiders are small arthropods that have colonized terrestrial environments. These impose three main problems: (i) terrestrial habitats have large fluctuations in temperature and humidity; (ii) the internal concentration of water is higher than the external environment in spiders, which exposes them continually to water loss; and (iii) their small body size determines a large surface/volume ratio, affecting energy exchange and influencing the life strategy. In this review we focus on body design, energetic, thermal selection, and water balance characteristics of some spider species present in Chile and correlate our results with ecological and behavioral information. Preferred temperatures and critical temperatures of Chilean spiders vary among species and individuals and may be adjusted by phenotypic plasticity. For example in the mygalomorph high-altitude spider Paraphysa parvula the preferred temperature is similar to that of the lowland spider Grammostola rosea; but while P. parvula shows phenotypic plasticity, G. rosea does not. The araneomorph spiders Loxosceles laeta and Scytodes globula have greater daily variations in preferred temperatures at twilight and during the night, which are set to the nocturnal activity rhythms of these species. They also present acclimation of the minimum critical temperatures. Dysdera crocata has a low preferred temperature adjusted to its favorite prey, the woodlouse. Spider metabolic rate is low compared to other arthropods, which may be associated with its sit and wait predatory strategy particularly in primitive hunter and weavers. In mygalomorph spiders the respiratory system is highly optimized with high oxygen conductance, for example G. rosea needs only a difference of 0.12–0.16 kPa in the oxygen partial pressure across the air-hemolymph barrier to satisfy its resting oxygen consumption demands. Water loss is a significant stress for spiders. Paraphysa parvula shows an evaporative water loss 10 times more than usual

  15. Coincidental intraguild predation by caterpillars on spider mites.

    Science.gov (United States)

    Shirotsuka, Kanako; Yano, Shuichi

    2012-01-29

    Intraguild predation (IGP) is defined as the killing and eating of prey species by a predator that also can utilize the resources of the prey. It is mainly reported among carnivores that share common herbivorous prey. However, a large chewing herbivore could prey upon sedentary and/or micro herbivores in addition to utilizing a host plant. To investigate such coincidental IGP, we observed the behavioral responses of the polyphagous mite Tetranychus kanzawai Kishida (Acari: Tetranychidae) when its host plant Cayratia japonica (Thunb.) Gagnep. (Vitaceae) was attacked by hornworms, Theretra japonica Boisduval (Sphingidae) and T. oldenlandiae Fabricius (Sphingidae). We also examined an interaction between the oligophagous mite Panonychus citri McGregor (Acari: Tetranychidae) and caterpillars of the swallowtail Papilio xuthus L. (Papilionidae) that share citrus plants as their main food source. Although all T. kanzawai and some active stage P. citri tried to escape from the coincidental IGP, some were consumed together with eggs, quiescent mites, and host plant leaves, suggesting that coincidental IGP occurs on spider mites in the wild. Moreover, neither hornworms nor swallowtail caterpillars distinguished between spider mite-infested and uninfested leaves, suggesting that the mite-infested leaves do not discourage caterpillar feeding. The reasons that the mites have no effective defense against coincidental IGP other than escaping are discussed. PMID:22286142

  16. The SPIDER fission fragment spectrometer for fission product yield measurements

    International Nuclear Information System (INIS)

    The SPectrometer for Ion DEtermination in fission Research (SPIDER) has been developed for measuring mass yield distributions of fission products from spontaneous and neutron-induced fission. The 2E–2v method of measuring the kinetic energy (E) and velocity (v) of both outgoing fission products has been utilized, with the goal of measuring the mass of the fission products with an average resolution of 1 atomic mass unit (amu). The SPIDER instrument, consisting of detector components for time-of-flight, trajectory, and energy measurements, has been assembled and tested using 229Th and 252Cf radioactive decay sources. For commissioning, the fully assembled system measured fission products from spontaneous fission of 252Cf. Individual measurement resolutions were met for time-of-flight (250 ps FWHM), spacial resolution (2 mm FHWM), and energy (92 keV FWHM for 8.376 MeV). Mass yield results measured from 252Cf spontaneous fission products are reported from an E–v measurement

  17. A dragline-forming mobile robot inspired by spiders

    International Nuclear Information System (INIS)

    Mobility of wheeled or legged machines can be significantly increased if they are able to move from a solid surface into a three-dimensional space. Although that may be achieved by addition of flying mechanisms, the payload fraction will be the limiting factor in such hybrid mobile machines for many applications. Inspired by spiders producing draglines to assist locomotion, the paper proposes an alternative mobile technology where a robot achieves locomotion from a solid surface into a free space. The technology resembles the dragline production pathway in spiders to a technically feasible degree and enables robots to move with thermoplastic spinning of draglines. As an implementation, a mobile robot has been prototyped with thermoplastic adhesives as source material of the draglines. Experimental results show that a dragline diameter range of 1.17–5.27 mm was achievable by the 185 g mobile robot in descending locomotion from the solid surface of a hanging structure with a power consumption of 4.8 W and an average speed of 5.13 cm min−1. With an open-loop controller consisting of sequences of discrete events, the robot has demonstrated repeatable dragline formation with a relative deviation within −4% and a length close to the metre scale. (paper)

  18. The SPIDER fission fragment spectrometer for fission product yield measurements

    Energy Technology Data Exchange (ETDEWEB)

    Meierbachtol, K.; Tovesson, F. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Shields, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Colorado School of Mines, Golden, CO 80401 (United States); Arnold, C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Blakeley, R. [University of New Mexico, Albuquerque, NM 87131 (United States); Bredeweg, T.; Devlin, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hecht, A.A.; Heffern, L.E. [University of New Mexico, Albuquerque, NM 87131 (United States); Jorgenson, J.; Laptev, A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mader, D. [University of New Mexico, Albuquerque, NM 87131 (United States); O' Donnell, J.M.; Sierk, A.; White, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-07-11

    The SPectrometer for Ion DEtermination in fission Research (SPIDER) has been developed for measuring mass yield distributions of fission products from spontaneous and neutron-induced fission. The 2E–2v method of measuring the kinetic energy (E) and velocity (v) of both outgoing fission products has been utilized, with the goal of measuring the mass of the fission products with an average resolution of 1 atomic mass unit (amu). The SPIDER instrument, consisting of detector components for time-of-flight, trajectory, and energy measurements, has been assembled and tested using {sup 229}Th and {sup 252}Cf radioactive decay sources. For commissioning, the fully assembled system measured fission products from spontaneous fission of {sup 252}Cf. Individual measurement resolutions were met for time-of-flight (250 ps FWHM), spacial resolution (2 mm FHWM), and energy (92 keV FWHM for 8.376 MeV). Mass yield results measured from {sup 252}Cf spontaneous fission products are reported from an E–v measurement.

  19. Spider silk-like proteins derived from transgenic Nicotiana tabacum.

    Science.gov (United States)

    Peng, Congyue Annie; Russo, Julia; Gravgaard, Charlene; McCartney, Heather; Gaines, William; Marcotte, William R

    2016-08-01

    The high tensile strength and biocompatibility of spider dragline silk makes it a desirable material in many engineering and tissue regeneration applications. Here, we present the feasibility to produce recombinant proteins in transgenic tobacco Nicotiana tabacum with sequences representing spider silk protein building blocks . Recombinant mini-spidroins contain native N- and C-terminal domains of major ampullate spidroin 1 (rMaSp1) or rMaSp2 flanking an abbreviated number (8, 16 or 32) of consensus repeat domains. Two different expression plasmid vectors were tested and a downstream chitin binding domain and self-cleavable intein were included to facilitate protein purification. We confirmed gene insertion and RNA transcription by PCR and reverse-transcriptase PCR, respectively. Mini-spidroin production was detected by N-terminus specific antibodies. Purification of mini-spidroins was performed through chitin affinity chromatography and subsequent intein activation with reducing reagent. Mini-spidroins, when dialyzed and freeze-dried, formed viscous gelatin-like fluids. PMID:27026165

  20. Spider web and silk performance landscapes across nutrient space

    Science.gov (United States)

    Blamires, Sean J.; Tseng, Yi-Hsuan; Wu, Chung-Lin; Toft, Søren; Raubenheimer, David; Tso, I.-Min

    2016-01-01

    Predators have been shown to alter their foraging as a regulatory response to recent feeding history, but it remains unknown whether trap building predators modulate their traps similarly as a regulatory strategy. Here we fed the orb web spider Nephila pilipes either live crickets, dead crickets with webs stimulated by flies, or dead crickets without web stimulation, over 21 days to enforce spiders to differentially extract nutrients from a single prey source. In addition to the nutrients extracted we measured web architectures, silk tensile properties, silk amino acid compositions, and web tension after each feeding round. We then plotted web and silk “performance landscapes” across nutrient space. The landscapes had multiple peaks and troughs for each web and silk performance parameter. The findings suggest that N. pilipes plastically adjusts the chemical and physical properties of their web and silk in accordance with its nutritional history. Our study expands the application of the geometric framework foraging model to include a type of predatory trap. Whether it can be applied to other predatory traps requires further testing. PMID:27216252

  1. Untangling taxonomy: a DNA barcode reference library for Canadian spiders.

    Science.gov (United States)

    Blagoev, Gergin A; deWaard, Jeremy R; Ratnasingham, Sujeevan; deWaard, Stephanie L; Lu, Liuqiong; Robertson, James; Telfer, Angela C; Hebert, Paul D N

    2016-01-01

    Approximately 1460 species of spiders have been reported from Canada, 3% of the global fauna. This study provides a DNA barcode reference library for 1018 of these species based upon the analysis of more than 30,000 specimens. The sequence results show a clear barcode gap in most cases with a mean intraspecific divergence of 0.78% vs. a minimum nearest-neighbour (NN) distance averaging 7.85%. The sequences were assigned to 1359 Barcode index numbers (BINs) with 1344 of these BINs composed of specimens belonging to a single currently recognized species. There was a perfect correspondence between BIN membership and a known species in 795 cases, while another 197 species were assigned to two or more BINs (556 in total). A few other species (26) were involved in BIN merges or in a combination of merges and splits. There was only a weak relationship between the number of specimens analysed for a species and its BIN count. However, three species were clear outliers with their specimens being placed in 11-22 BINs. Although all BIN splits need further study to clarify the taxonomic status of the entities involved, DNA barcodes discriminated 98% of the 1018 species. The present survey conservatively revealed 16 species new to science, 52 species new to Canada and major range extensions for 426 species. However, if most BIN splits detected in this study reflect cryptic taxa, the true species count for Canadian spiders could be 30-50% higher than currently recognized. PMID:26175299

  2. Structure and composition of the spider Argiope amoena egg case

    Directory of Open Access Journals (Sweden)

    JIANG Ping

    2008-10-01

    Full Text Available The egg case of the spider A. amoena is composed of multiple layers of silk, including a frame of yellow silk, an outer cover with layers of gray-green, pale brown, and white silk, and an inner cover of brown silk. SEM shows the outer cover threads consist of six large diameter (4.8–6.8 µm cylindrical gland monofilaments with numerous smaller diameter (0.26–0.76 µm fibers. The number of small-diameter fibers varies with layer; it is high in outer layers and decreases in inner layers. Small diameter fibers are absent from the inner cover, which consisted entirely of fibers made with six strands of large diameter (5.2 µm cylindrical gland monofilaments. The chemical makeup (mole fraction of alanine, serine, and glycine of the outer cover strands is intermediate between that of inner cover silk and aciniform gland silk. These observations support Matthew's (2002 hypothesis that the small diameter fibers are produced by the aciniform glands. Spiders appear to use relatively few gland silks in varying combinations to achieve different physical, chemical (e.g. color, diameter, amino acid composition and functional (mechanical properties, resistance, etc characteristics in different layers of the egg case providing protections for eggs or spiderlings [Acta Zoologica Sinica 54 (5: 918 – 927, 2008].

  3. Benefits of cooperation with genetic kin in a subsocial spider.

    Science.gov (United States)

    Schneider, J M; Bilde, T

    2008-08-01

    Interaction within groups exploiting a common resource may be prone to cheating by selfish actions that result in disadvantages for all members of the group, including the selfish individuals. Kin selection is one mechanism by which such dilemmas can be resolved. This is because selfish acts toward relatives include the cost of lowering indirect fitness benefits that could otherwise be achieved through the propagation of shared genes. Kin selection theory has been proved to be of general importance for the origin of cooperative behaviors, but other driving forces, such as direct fitness benefits, can also promote helping behavior in many cooperatively breeding taxa. Investigating transitional systems is therefore particularly suitable for understanding the influence of kin selection on the initial spread of cooperative behaviors. Here we investigated the role of kinship in cooperative feeding. We 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 in prey capture and feed communally. We provide clear experimental evidence for net benefits of cooperating with kin. Genetic relatedness within groups and not association with familiar individuals directly improved feeding efficiency and growth rates, demonstrating a positive effect of kin cooperation. Hence, in communally feeding spiders, nepotism favors group retention and reduces the conflict between selfish interests and the interests of the group. PMID:18658236

  4. Nectar Meals of a Mosquito-Specialist Spider

    Directory of Open Access Journals (Sweden)

    Josiah O. Kuja

    2012-01-01

    Full Text Available Evarcha culicivora, an East African jumping spider, is known for feeding indirectly on vertebrate blood by actively choosing blood-carrying mosquitoes as prey. Using cold-anthrone tests to detect fructose, we demonstrate that E. culicivora also feeds on nectar. Field-collected individuals, found on the plant Lantana camara, tested positive for plant sugar (fructose. In the laboratory, E. culicivora tested positive for fructose after being kept with L. camara or one of another ten plant species (Aloe vera, Clerodendron magnifica, Hamelia patens, Lantana montevideo, Leonotis nepetaefolia, Parthenium hysterophorus, Ricinus communis, Senna didymobotrya, Striga asiatica, and Verbena trivernia. Our findings demonstrate that E. culicivora acquires fructose from its natural diet and can ingest fructose directly from plant nectaries. However, experiments in the laboratory also show that E. culicivora can obtain fructose indirectly by feeding on prey that have fed on fructose, implying a need to consider this possibility when field-collected spiders test positive for fructose. In laboratory tests, 53.5% of 1,215 small juveniles, but only 3.4% of 622 adult E. culicivora, left with plants for 24 hours, were positive for fructose. These findings, along with the field data, suggest that fructose is especially important for early-instar juveniles of E. culicivora.

  5. Predator perception of detritus and eggsac decorations spun by orb-web spiders Cyclosa octotuberculata: Do they function to camouflage the spiders?

    Directory of Open Access Journals (Sweden)

    Wenjin GAN, Fengxiang LIU, Zengtao ZHANG, Daiqin LI

    2010-06-01

    Full Text Available Camouflage is one of the most widespread and powerful strategies that animals use to make detection/recognition more difficult. Many orb-web spiders of the genus Cyclosa add prey remains, plant debris, moults, and/or eggsacs to their webs called web decorations. Web decorations resembling spider body colour pattern have been considered to camouflage the spider from predators. While this camouflage is obvious from a human’s perspective, it has rarely been investigated from a predator’s perspective. In this study, we tested the visibility of web decorations by calculating chromatic and achromatic contrasts of detritus and eggsac decorations built by Cyclosa octotuberculata, against four different backgrounds viewed by both bird (e.g., blue tits and hymenopteran (e.g. wasps predators. We showed that both juvenile and adult spiders on webs with detritus or egg-sac decorations were undetectable by both hymenopteran and bird predators over short and long distances. Our results thus suggest that decorating webs with detritus or eggsacs by C. octotuberculata may camouflage the spider from both hymenopteran and bird predators in their common habitats [Current Zoology 56 (3: 379–387, 2010].

  6. Degree of threat of spider fauna in geomorphological units; 1 : 1 500 000

    International Nuclear Information System (INIS)

    The degree of threat of invertebrates is documented by threat of spiders, which are comparatively well known in Slovakia. Apart from it, spiders are considered indicators of the state of the natural environment. In the territory of Slovakia 927 species of spiders are known. Out of it 70 species (7.6 %) are classified in the category of critically threatened species and 87 species (9.8 %) are classified as threatened, 17 species are protected pursuing the Decree of the Ministry of Environment of the Slovak Republic No. 93/199 of the Coll. In order to express the degree of threat, the share of critically threatened and threatened species in the total number of the known species in the individual geomorphological units was selected with their representation in individual geomorphological units. The number of critically threatened species is quoted and occurrence of 17 protected spider species is represented in order to illustrate the current situation. (authors)

  7. Effects of traditional coppicing and game keeping in European lowland forests on epigeic spiders

    Czech Academy of Sciences Publication Activity Database

    Tropek, R.; Spitzer, L.; Konvička, Martin; Beneš, Jiří

    Bern : Natural History Museum Bern, 2008. s. 139-139. [European Congress of Arachnology /24./. 25.08.2008-29.08.2008, Bern] Institutional research plan: CEZ:AV0Z50070508 Keywords : epigeic spiders Subject RIV: EH - Ecology, Behaviour

  8. Envia garciai, a new genus and species of mygalomorph spiders (Araneae, Microstigmatidae from Brazilian Amazonia

    Directory of Open Access Journals (Sweden)

    Ott Ricardo

    2003-01-01

    Full Text Available The genus Envia, comprising only the new species Envia garciai, is proposed. These small mygalomorph spiders were abundantly collected in soil cores and litter samples in primary rain forests near Manaus, Amazonas, Brazil.

  9. [Effect of Segestria florentina spider venom on the mechanism of inactivation of sodium channels].

    Science.gov (United States)

    Usmanov, P B; Kalikulov, D; Nasledov, G A; Tashmukhamedov, B A

    1985-01-01

    It was shown that Segestria florentina spider venom mainly reduces the rate and amount of sodium inactivation. This effect is likely to be responsible for the prolongation of the action potential. PMID:2413900

  10. SpiderFab: Architecture for On-Orbit Construction of Kilometer-Scale Apertures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The SpiderFab effort has investigated the value proposition and technical feasibility of radically changing the way we build and deploy spacecraft in order to...

  11. Prediction of abundance of forest spiders according to climate warming in South Korea

    Directory of Open Access Journals (Sweden)

    Tae-Sung Kwon

    2014-06-01

    Full Text Available Distribution of spiders will be changed as climate warms. Abundance of spider species was predicted nationwide in South Korea. Abundance of spiders was projected using temperature species distribution model based on a nationwide data (366 forest sites according to climate change scenario RCP 4.5 and 8.5. The model predicts that 9 out of 17 species will increase in abundance while 8 species will decrease. Based on this finding, a qualitative prediction (increase or decrease was conducted on the species with more than 1% occurrence: 68 species are expected to decrease, 9 to increase, and 8 to change a little. In pooled estimation, 76 species (75% are expected to decrease, 18 species (18% to increase, and by 8 species (8% to have little change. The projection indicates that majority of spider species will decrease, but minority of species will increase as climate warms, suggesting great increase of remained species in lowlands.

  12. Spiders (Araneae) of the Moosehorn National Wildlife Refuge, Washington County, Maine

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes my identifications of spiders for graduate student Matthew Vander Haegen, College of Forest Resources, Department of Wildlife, University of...

  13. SPIDER: Listening for the echoes of inflation from above the clouds

    Science.gov (United States)

    Filippini, Jeffrey; Spider Collaboration

    2016-03-01

    We report on the status of SPIDER, a balloon-borne instrument to map the polarization of the cosmic microwave background at large angular scales. SPIDER targets the B-mode signature of primordial gravitational waves, with a focus on mapping a large sky area at multiple frequencies. SPIDER's six monochromatic refracting telescopes (three each at 95 and 150 GHz) feed a total of more than 2000 antenna-coupled superconducting transition-edge sensors. A sapphire half-wave plate at the aperture of each telescope modulates sky polarization for control of systematics. We discuss SPIDER's first long-duration balloon flight in January 2015, as well as the status of data analysis and development toward a second flight.

  14. Pre-flight integration and characterization of the SPIDER balloon-borne telescope

    CERN Document Server

    Rahlin, A S; Amiri, M; Benton, S J; Bock, J J; Bond, J R; Bryan, S A; Chiang, H C; Contaldi, C R; Crill, B P; Doré, O; Farhang, M; Filippini, J P; Fissel, L M; Fraisse, A A; Gambrel, A E; Gandilo, N N; Golwala, S; Gudmundsson, J E; Halpern, M; Hasselfield, M F; Hilton, G; Holmes, W A; Hristov, V V; Irwin, K D; Jones, W C; Kermish, Z D; Kuo, C L; MacTavish, C J; Mason, P V; Megerian, K; Moncelsi, L; Morford, T A; Nagy, J M; Netterfield, C B; O'Brient, R; Reintsema, C; Ruhl, J E; Runyan, M C; Shariff, J A; Soler, J D; Trangsrud, A; Tucker, C; Tucker, R S; Turner, A D; Weber, A C; Wiebe, D V; Young, E Y

    2014-01-01

    We present the results of integration and characterization of the SPIDER instrument after the 2013 pre-flight campaign. SPIDER is a balloon-borne polarimeter designed to probe the primordial gravitational wave signal in the degree-scale $B$-mode polarization of the cosmic microwave background. With six independent telescopes housing over 2000 detectors in the 94 GHz and 150 GHz frequency bands, SPIDER will map 7.5% of the sky with a depth of 11 to 14 $\\mu$K$\\cdot$arcmin at each frequency, which is a factor of $\\sim$5 improvement over Planck. We discuss the integration of the pointing, cryogenic, electronics, and power sub-systems, as well as pre-flight characterization of the detectors and optical systems. SPIDER is well prepared for a December 2014 flight from Antarctica, and is expected to be limited by astrophysical foreground emission, and not instrumental sensitivity, over the survey region.

  15. Biomimetic Spider Leg Joints: A Review from Biomechanical Research to Compliant Robotic Actuators

    Directory of Open Access Journals (Sweden)

    Stefan Landkammer

    2016-07-01

    Full Text Available Due to their inherent compliance, soft actuated joints are becoming increasingly important for robotic applications, especially when human-robot-interactions are expected. Several of these flexible actuators are inspired by biological models. One perfect showpiece for biomimetic robots is the spider leg, because it combines lightweight design and graceful movements with powerful and dynamic actuation. Building on this motivation, the review article focuses on compliant robotic joints inspired by the function principle of the spider leg. The mechanism is introduced by an overview of existing biological and biomechanical research. Thereupon a classification of robots that are bio-inspired by spider joints is presented. Based on this, the biomimetic robot applications referring to the spider principle are identified and discussed.

  16. Fischer Black

    OpenAIRE

    Robert C. Merton; Myron S. Scholes

    2013-01-01

    ReprintThis article was originally published by Wiley for the American Finance Association (Merton RC, Scholes MS. 1995. Fischer Black. J. Finance 50(5):1359–70). It is reprinted with permission from John Wiley and Sons © 1995. Reference formatting was updated to facilitate linking.

  17. Airflow elicits a spider's jump towards airborne prey. I. Airflow around a flying blowfly.

    Science.gov (United States)

    Klopsch, Christian; Kuhlmann, Hendrik C; Barth, Friedrich G

    2012-10-01

    The hunting spider Cupiennius salei uses airflow generated by flying insects for the guidance of its prey-capture jump. We investigated the velocity field of the airflow generated by a freely flying blowfly close to the flow sensors on the spider's legs. It shows three characteristic phases (I-III). (I) When approaching, the blowfly induces an airflow signal near the spider with only little fluctuation (0.013 ± 0.006 m s(-1)) and a strength that increases nearly exponentially with time (maximum: 0.164 ± 0.051 m s(-1) s.d.). The spider detects this flow while the fly is still 38.4 ± 5.6 mm away. The fluctuation of the airflow above the sensors increases linearly up to 0.037 m s(-1) with the fly's altitude. Differences in the time of arrival and intensity of the fly signal at different legs probably inform the spider about the direction to the prey. (II) Phase II abruptly follows phase I with a much higher degree of fluctuation (fluctuation amplitudes: 0.114 ± 0.050 m s(-1)). It starts when the fly is directly above the sensor and corresponds to the time-dependent flow in the wake below and behind the fly. Its onset indicates to the spider that its prey is now within reach and triggers its jump. The spider derives information on the fly's position from the airflow characteristics, enabling it to properly time its jump. The horizontal velocity of the approaching fly is reflected by the time of arrival differences (ranging from 0.038 to 0.108 s) of the flow at different legs and the exponential velocity growth rate (16-79 s(-1)) during phase I. (III) The air flow velocity decays again after the fly has passed the spider. PMID:22572032

  18. Airflow elicits a spider's jump towards airborne prey. II. Flow characteristics guiding behaviour.

    Science.gov (United States)

    Klopsch, Christian; Kuhlmann, Hendrik C; Barth, Friedrich G

    2013-05-01

    When hungry, the wandering spider Cupiennius salei is frequently seen to catch flying insect prey. The success of its remarkable prey-capture jump from its sitting plant into the air obviously depends on proper timing and sensory guidance. In this study, it is shown that particular features of the airflow generated by the insect suffice to guide the spider. Vision and the reception of substrate vibrations and airborne sound are not needed. The behavioural reactions of blinded spiders were examined by exposing them to natural and synthetic flows imitating the fly-generated flow or particular features of it. Thus, the different roles of the three phases previously identified in the fly-generated flow and described in the companion paper could be demonstrated. When exposing the spider to phase I flow only (exponentially increasing flow velocity with very little fluctuation and typical of the fly's approach), an orienting behaviour could be observed but a prey-capture jump never be elicited. Remarkably, the spider reacted to the onset of phase II (highly fluctuating flow) of a synthetically generated flow field with a jump as frequently as it did when exposed to natural fly-generated flows. In all cases using either natural or artificial flows, the spider's jump was triggered before its flow sensors were hit by phase III flow (steadily decreasing airflow velocity). Phase III may tell the spider that the prey has passed by already in case of no prey-capture reaction. Our study underlines the relevance of airflow in spider behaviour. It also reflects the sophisticated workings of their flow sensors (trichobothria) previously studied in detail. Presumably, the information contained in prey-generated airflows plays a similar role in many other arthropods. PMID:23427092

  19. Transcriptome analysis of Loxosceles laeta (Araneae, Sicariidae) spider venomous gland using expressed sequence tags

    OpenAIRE

    Almeida Diego D; Kobashi Leonardo S.; Gonçalves-de-Andrade Rute M.; Junqueira-de-Azevedo Inácio de LM; Fernandes-Pedrosa Matheus de F; Ho Paulo L; Tambourgi Denise V

    2008-01-01

    Abstract Background The bite of spiders belonging to the genus Loxosceles can induce a variety of clinical symptoms, including dermonecrosis, thrombosis, vascular leakage, haemolysis, and persistent inflammation. In order to examine the transcripts expressed in venom gland of Loxosceles laeta spider and to unveil the potential of its products on cellular structure and functional aspects, we generated 3,008 expressed sequence tags (ESTs) from a cDNA library. Results All ESTs were clustered int...

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

    OpenAIRE

    Hénaut, Yann; Corbara, Bruno; Pélozuelo, Laurent; Azémar, Frédéric; Céréghino, Régis; Herault, Bruno; Dejean, Alain

    2014-01-01

    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 rec...

  1. Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion.

    Science.gov (United States)

    Smith, Jennifer N; Emlen, Douglas J; Pearson, Dean E

    2016-01-01

    Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders' web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely to capture prey, leading to >2-fold increases in recruitment. Orb-weavers showed no differences in web size or prey captures between treatments. Web-spider responses to simulated invasion mimicked patterns following natural invasions, confirming that C. stoebe's architecture is likely the primary attribute driving native spider responses to these invasions. Differences in spider responses were attributable to differences in web construction behaviors relative to historic web substrate constraints. Orb-weavers in this system constructed webs between multiple plants, so they were limited by the overall quantity of native substrates but not by the architecture of individual native plant species. Irregular web-spiders built their webs within individual plants and were greatly constrained by the diminutive architecture of native plant substrates, so they were limited both by quantity and quality of native substrates. Evaluating native species traits in the context of invader-driven change can explain invasion outcomes and help to identify factors limiting native populations. PMID:27082240

  2. A Novel Hyaluronidase from Brown Spider (Loxosceles intermedia) Venom (Dietrich's Hyaluronidase): From Cloning to Functional Characterization

    OpenAIRE

    Valéria Pereira Ferrer; Thiago Lopes de Mari; Luiza Helena Gremski; Dilza Trevisan Silva; Rafael Bertoni da Silveira; Waldemiro Gremski; Olga Meiri Chaim; Andrea Senff-Ribeiro; Helena Bonciani Nader; Silvio Sanches Veiga

    2013-01-01

    Loxoscelism is the designation given to clinical symptoms evoked by Loxosceles spider's bites. Clinical manifestations include skin necrosis with gravitational spreading and systemic disturbs. The venom contains several enzymatic toxins. Herein, we describe the cloning, expression, refolding and biological evaluation of a novel brown spider protein characterized as a hyaluronidase. Employing a venom gland cDNA library, we cloned a hyaluronidase (1200 bp cDNA) that encodes for a signal peptide...

  3. Herbivory in Spiders: The Importance of Pollen for Orb-Weavers

    OpenAIRE

    Eggs, Benjamin; Sanders, Dirk

    2013-01-01

    Orb-weaving spiders (Araneidae) are commonly regarded as generalist insect predators but resources provided by plants such as pollen may be an important dietary supplementation. Their webs snare insect prey, but can also trap aerial plankton like pollen and fungal spores. When recycling their orb webs, the spiders may therefore also feed on adhering pollen grains or fungal spores via extraoral digestion. In this study we measured stable isotope ratios in the bodies of two araneid species (Acu...

  4. Species richness and composition assessment of spiders in a Mediterranean scrubland

    OpenAIRE

    Cardoso, Pedro; Henriques, Sérgio; Gaspar, Clara; Crespo, Luis; Carvalho, Rui; Schmidt, Jesper; Sousa, Pedro; Szuts, Tamás

    2007-01-01

    Abstract Intensive fieldwork has been undertaken in Portugal in order to develop a standardized and optimized sampling protocol for Mediterranean spiders. The present study had the objectives of testing the use of semi-quantitative sampling for obtaining an exhaustive species richness assessment of spiders and testing the effects of day, time of day, collector and sampling method on the collected species richness and composition of a Mediterranean scrubland. The collecting summed 224 samples...

  5. Potential lethal and non-lethal effects of predators on dispersal of spider mites.

    OpenAIRE

    Otsuki, Hatsune; Yano, Shuichi

    2014-01-01

    Predators can affect prey dispersal lethally by direct consumption or non-lethally by making prey hesitate to disperse. These lethal and non-lethal effects are detectable only in systems where prey can disperse between multiple patches. However, most studies have drawn their conclusions concerning the ability of predatory mites to suppress spider mites based on observations of their interactions on a single patch or on heavily infested host plants where spider mites could hardly disperse towa...

  6. Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion

    OpenAIRE

    Smith, Jennifer N.; Emlen, Douglas J.; Pearson, Dean E.

    2016-01-01

    Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders’ web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 t...

  7. Osteomyelitis of the Mandibular Symphysis Caused by Brown Recluse Spider Bite

    OpenAIRE

    Naidu, Deepak K.; Ghurani, Rami; Salas, R. Emerick; Mannari, Rudolph J.; Robson, Martin C.; Payne, Wyatt G.

    2008-01-01

    Background: Brown recluse spider bites cause significant trauma via their tissue toxic venom. Diagnosis of these injuries and envenomation is difficult and many times presumptive. Treatment is varied and dependent upon presentation and course of injury. Materials and Methods: We present a case of a previously unreported incidence of osteomyelitis of the mandible as a result of a brown recluse spider bite. A review of the literature and discussion of diagnosis and treatment of brown recluse sp...

  8. Effects of spider Macrothele raven venom on cell proliferation and cytotoxicity in HeLa cells

    Institute of Scientific and Technical Information of China (English)

    Li GAO; Bao-en SHAN; Jing CHEN; Jiang-hui LIU; Da-xiang SONG; Bao-cheng ZHU

    2005-01-01

    Aim: To examine the effect of venom from the spider Macrothele raven on cell proliferation and cytotoxicity in human cervical carcinoma, HeLa cells. Methods:Morphological and biochemical signs of apoptosis appeared using acridine orange-ethidium bromide (AO/EB) staining. Marked morphological changes in HeLa cells after treatment with spider venom were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cell proliferation and cytotoxicity were determined by [methyl-3H] thymidine assay ([3H]TdR) and lactate dehydrogenase (LDH) release, respectively. DNA fragmentation and cell cycle distribution were monitored using flow cytometry. In addition, Western blot analysis was used to evaluate the level of caspase-3 expression. In vivo examination of the inhibition of the size of tumors in nude mice treated with spider venom was measured. Results: Marked morphological changes were observed using AO/EB staining, SEM and TEM assay. Spider venom at concentrations of 10-40 mg/L caused dose- and time-dependent inhibition of HeLa cell proliferation.The ratio of apoptosis and necrosis increased. The activity of caspase-3 was upregulated after spider venom treatment. In vivo study of tumor size revealed that tumors significantly decreased in size from controls to tumors treated for 3 weeks with spider venom (P<0.05). Conclusion: The inhibition of HeLa cells by the venom of the spider Macrothele raveni was carried out in three ways: induction of apoptosis, necrosis of toxicity damage and direct lysis. Spider venom is a novel anti-tumor material both in vitro and in vivo.

  9. Hymenopteran parasitoids of the ant-eating spider Zodarion styliferum (Simon (Araneae, Zodariidae

    Directory of Open Access Journals (Sweden)

    Stanislav Korenko

    2013-02-01

    Full Text Available Calymmochilus dispar Bouček & Andriescu (Hymenoptera, Eupelmidae and Gelis apterus (Pontoppidan (Hymenoptera, Ichneumonidae are newly recorded as parasitoids of the ant-eating spider Zodarion styliferum (Simon (Araneae, Zodariidae. The larvae of both parasitoid species fed on juvenile spiders. The final instar larva and pupa of C. dispar and the male of G. apterus are described for the first time. Both species represent new distribution records for Portugal. The biology and host associations of the parasitoids are discussed.

  10. Development of a Process for the Spinning of Synthetic Spider Silk

    OpenAIRE

    Copeland, Cameron G.; Bell, Brianne E.; Christensen, Chad D.; Lewis, Randolph V.

    2015-01-01

    Spider silks have unique mechanical properties but current efforts to duplicate those properties with recombinant proteins have been unsuccessful. This study was designed to develop a single process to spin fibers with excellent and consistent mechanical properties. As-spun fibers produced were brittle, but by stretching the fibers the mechanical properties were greatly improved. A water-dip or water-stretch further increased the strength and elongation of the synthetic spider silk fibers. Gi...

  11. Communities of ground-living spiders in deciduous forests: Does tree species diversity matter?

    OpenAIRE

    Schuldt, Andreas; Fahrenholz, Nadine; Brauns, Mascha; Migge-Kleian, Sonja; Platner, Christian; Schaefer, Matthias

    2008-01-01

    The relationships between species diversity and ecosystem functions are in the focus of recent ecological research. However, until now the influence of species diversity on ecosystem processes such as decomposition or mineral cycling is not well understood. In deciduous forests, spiders are an integral part of the forest floor food web. In the present study, patterns of spider diversity and community structure are related to diversity of deciduous forest stands in the Hainich National Park (T...

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

    OpenAIRE

    Yann Hénaut; Bruno Corbara; Laurent Pélozuelo; Frédéric Azémar; Régis Céréghino; Bruno Herault; Alain Dejean

    2014-01-01

    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 rec...

  13. Spider mites suppress tomato defenses downstream of jasmonate and salicylate independently of hormonal crosstalk

    OpenAIRE

    Alba, J M; Schimmel, B.C.J.; Glas, J. J.; Ataide, L.M.S.; Pappas, M.L.; Villarroel, C.A.; Schuurink, R.C.; Sabelis, M.W.; Kant, M.R.

    2014-01-01

    Plants respond to herbivory by mounting a defense. Some plant-eating spider mites (Tetranychus spp.) have adapted to plant defenses to maintain a high reproductive performance. From natural populations we selected three spider mite strains from two species, Tetranychus urticae and Tetranychus evansi, that can suppress plant defenses, using a fourth defense-inducing strain as a benchmark, to assess to which extent these strains suppress defenses differently. We characterized timing and magnitu...

  14. Does women’s greater fear of snakes and spiders originate in infancy?

    OpenAIRE

    Rakison, David H.

    2009-01-01

    Previous studies with adult humans and non-human animals revealed more rapid fear learning for spiders and snakes than for mushrooms and flowers. The current experiments tested whether 11-month-olds show a similar effect in learning associative pairings between facial emotions and fear-relevant and fear-irrelevant stimuli. Consistent with the greater incidence of snake and spider phobias in women, results show that female but not male infants learn rapidly to associate negative facial emotion...

  15. Physical characterization of functionalized spider silk: electronic and sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Steven, Eden; Brooks, James S [Department of Physics and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, FL 32310 (United States); Park, Jin Gyu [FAMU-FSU Department of Industrial and Manufacturing Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Ave., Tallahassee, FL 32310 (United States); Paravastu, Anant; Siegrist, Theo; Kaner, Papatya; Alamo, Rufina G [FAMU-FSU Department of Chemical and Biomedical Engineering and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, FL 32310 (United States); Branco Lopes, Elsa [Departamento de Quimica, Instituto Tecnologico e Nuclear/CFMC-UL, P-2686-953 Sacavem (Portugal); Englander, Ongi, E-mail: esteven@magnet.fsu.edu [FAMU-FSU Department of Mechanical Engineering and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, Florida 32310 (United States)

    2011-10-15

    This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of {beta}-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 deg. C, has a strong effect on the morphology of silk bundles (increasing their size), on the process of pyrolization (suppressing mass loss rates) and on the resulting carbonized fiber structure (that becomes more robust against bending and strain). The effects of iodine doping and other functional parameters (vacuum and thin film coating) motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR) to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and {beta}-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR) spectroscopy, revealing a partial transformation of {beta}-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof

  16. Physical characterization of functionalized spider silk: electronic and sensing properties

    International Nuclear Information System (INIS)

    This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 deg. C, has a strong effect on the morphology of silk bundles (increasing their size), on the process of pyrolization (suppressing mass loss rates) and on the resulting carbonized fiber structure (that becomes more robust against bending and strain). The effects of iodine doping and other functional parameters (vacuum and thin film coating) motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR) to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and β-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR) spectroscopy, revealing a partial transformation of β-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof-of-concept applications of

  17. Physical characterization of functionalized spider silk: electronic and sensing properties

    Directory of Open Access Journals (Sweden)

    Eden Steven, Jin Gyu Park, Anant Paravastu, Elsa Branco Lopes, James S Brooks, Ongi Englander, Theo Siegrist, Papatya Kaner and Rufina G Alamo

    2011-01-01

    Full Text Available This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline and amorphous (helical structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 °C, has a strong effect on the morphology of silk bundles (increasing their size, on the process of pyrolization (suppressing mass loss rates and on the resulting carbonized fiber structure (that becomes more robust against bending and strain. The effects of iodine doping and other functional parameters (vacuum and thin film coating motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and β-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR spectroscopy, revealing a partial transformation of β-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  19. Local and Landscape Correlates of Spider Activity Density and Species Richness in Urban Gardens.

    Science.gov (United States)

    Otoshi, Michelle D; Bichier, Peter; Philpott, Stacy M

    2015-08-01

    Urbanization is a major threat to arthropod biodiversity and abundance due to reduction and loss of suitable natural habitat. Green spaces and small-scale agricultural areas may provide habitat and resources for arthropods within densely developed cities. We studied spider activity density (a measure of both abundance and degree of movement) and diversity in urban gardens in Santa Cruz, Santa Clara, and Monterey counties in central California, USA. We sampled for spiders with pitfall traps and sampled 38 local site characteristics for 5 mo in 19 garden sites to determine the relative importance of individual local factors. We also analyzed 16 landscape variables at 500-m and 1-km buffers surrounding each garden to determine the significance of landscape factors. We identified individuals from the most common families to species and identified individuals from other families to morphospecies. Species from the families Lycosidae and Gnaphosidae composed 81% of total adult spider individuals. Most of the significant factors that correlated with spider activity density and richness were local rather than landscape factors. Spider activity density and richness increased with mulch cover and flowering plant species, and decreased with bare soil. Thus, changes in local garden management have the potential to promote diversity of functionally important spiders in urban environments. PMID:26314049

  20. Evaluation of the efficacy of vacuum cleaners for the integrated control of brown spider Loxosceles intermedia

    Directory of Open Access Journals (Sweden)

    E. N. Ramires

    2007-01-01

    Full Text Available Some venomous spiders of the genus Loxosceles can reach high population densities inside and around houses. In Brazil, most spider accidents are related to Loxosceles intermedia. Control of loxoscelism should utilize integrated pest management tools, such as vacuum cleaners, to eliminate egg sacs, webs and spiders. The present study tested the efficacy of one type of vacuum cleaner (for professional and domestic use in the control of L. intermedia populations. Cockroaches (Pycnoscelus surinamensis were used in some tests for comparison. Vacuuming using standard accessories or a paper tube resulted in the death of all female (n=60, male (n=60, young (n=60 and just-hatched (n=60 L. intermedia, and all egg sacs (n=5 were destroyed. The removal of the plastic plate present at the bottom of the vacuuming tube inside the machine allowed some spiders to survive the vacuuming process. When kept inside a vacuum bag full of dust and debris, adult females (n=10 survived for 10 days; however, significant mortality was observed among male (n=10 and young individuals (n=10. Addition of cornstarch to the vacuum bag did not affect the spiders (n=20. Vacuum cleaners, such as the one used in the present investigation, are promising tools for integrated management of L. intermedia and other spiders in domestic environments.

  1. Stage-based mortality of grassland grasshoppers (Acrididae) from wandering spider (Lycosidae) predation

    Science.gov (United States)

    Oedekoven, Mark A.; Joern, Anthony

    1998-12-01

    Mortality rates in insects, including grasshoppers (Acrididae), are often stage- or size-specific. We estimated stage-specific mortality rates for three common grasshopper species from a Nebraska (USA) sandhills grassland ( Ageneotettix deorum, Melanoplus sanguinipes and Phoetaliotes nebrascensis), and partitioned the impact due to wandering spider predation from remaining sources. Survivorship was estimated for multiple developmental stages (3rd instar through adult) under experimental conditions that either prevented or permitted predation from free-living, wandering spiders (primarily Schizocosa species). Total stage-specific mortality, including spider predation, examined over the period of single stages was greatest for the youngest stages (91% for 3rd instar, 73% for 4th instar, 63.5% for 5th instar and 30.4% for adults). For the developmental stages considered and averaged for all species, the contribution to total mortality from spider predation over the 10-d period (approximately the length of a developmental stage) ranged from 17% for 3rd instar nymphs to 23% for 4th and 5th instars, and an undetectable level for adults. While spiders may depress grasshopper numbers, contributions from spider predation to grasshopper population dynamics are uncertain.

  2. Influence of host plant species on the development and reproduction of hawthorn spider mites

    Institute of Scientific and Technical Information of China (English)

    Li Dingxu; Hou Yueli; Shen Zuorui

    2006-01-01

    A leaf disc bioassay was employed to investigate the influence of host species of deciduous fruit trees,like apple,peach,plum,cherry and apricot,on the development and reproduction of the hawthorn spider mite Tetranychus viennensis Zacher in the laboratory under conditions of 25±1℃,60±10% RH and a photoperiod of 16 h: 8 h light:dark.This was done by determining the duration of each life stage of the mites,the intrinsic rate of population increase (Tm),mean generation time (T) and net reproductive rate (R0)of the spider mites on each of the host plant species.Differences in life table parameters of the spider mite among host plants were analyzed with the jack-knife method.The results indicated that plum might be the best suitable plant for the spider mite among the plants tested due to shorter developmental period and higher intrinsic rate of increase,whereas cherry and apricot were least suitable due to their long developmental duration and low intrinsic rates of increase.When the spider mites were transferred from apple to other fruit trees,negative effects on developmental duration, fecundity and life table parameters were found in the first generation,but the effects faded out in succeeding generations.When transferred onto plum and peach,the spider mite adapted to the new hosts in the second generation;however,on cherry and apricot,it adapted in the third generation.

  3. Herbivory in spiders: the importance of pollen for orb-weavers.

    Science.gov (United States)

    Eggs, Benjamin; Sanders, Dirk

    2013-01-01

    Orb-weaving spiders (Araneidae) are commonly regarded as generalist insect predators but resources provided by plants such as pollen may be an important dietary supplementation. Their webs snare insect prey, but can also trap aerial plankton like pollen and fungal spores. When recycling their orb webs, the spiders may therefore also feed on adhering pollen grains or fungal spores via extraoral digestion. In this study we measured stable isotope ratios in the bodies of two araneid species (Aculepeira ceropegia and Araneus diadematus), their potential prey and pollen to determine the relative contribution of pollen to their diet. We found that about 25% of juvenile orb-weaving spiders' diet consisted of pollen, the other 75% of flying insects, mainly small dipterans and hymenopterans. The pollen grains in our study were too large to be taken up accidentally by the spiders and had first to be digested extraorally by enzymes in an active act of consumption. Therefore, pollen can be seen as a substantial component of the spiders' diet. This finding suggests that these spiders need to be classified as omnivores rather than pure carnivores. PMID:24312430

  4. Potential lethal and non-lethal effects of predators on dispersal of spider mites.

    Science.gov (United States)

    Otsuki, Hatsune; Yano, Shuichi

    2014-11-01

    Predators can affect prey dispersal lethally by direct consumption or non-lethally by making prey hesitate to disperse. These lethal and non-lethal effects are detectable only in systems where prey can disperse between multiple patches. However, most studies have drawn their conclusions concerning the ability of predatory mites to suppress spider mites based on observations of their interactions on a single patch or on heavily infested host plants where spider mites could hardly disperse toward intact patches. In these systems, specialist predatory mites that penetrate protective webs produced by spider mites quickly suppress the spider mites, whereas generalist predators that cannot penetrate the webs were ineffective. By using a connected patch system, we revealed that a generalist ant, Pristomyrmex punctatus Mayr (Hymenoptera: Formicidae), effectively prevented dispersal of spider mites, Tetranychus kanzawai Kishida (Acari: Tetranychidae), by directly consuming dispersing individuals. We also revealed that a generalist predatory mite, Euseius sojaensis Ehara (Acari: Phytoseiidae), prevented between-patch dispersal of T. kanzawai by making them hesitate to disperse. In contrast, a specialist phytoseiid predatory mite, Neoseiulus womersleyi Schicha, allowed spider mites to escape an initial patch, increasing the number of colonized patches within the system. Our results suggest that ants and generalist predatory mites can effectively suppress Tetranychus species under some conditions, and should receive more attention as agents for conservation biological control in agroecosystems. PMID:24867061

  5. Fecal and Salivary Cortisol Concentrations in Woolly (Lagothrix ssp. and Spider Monkeys (Ateles spp.

    Directory of Open Access Journals (Sweden)

    Kimberly D. Ange-van Heugten

    2009-01-01

    Full Text Available Detrimental physiological effects due to stressors can contribute to the low captive success of primates. The objective of this research was to investigate the potential impact of diet composition on cortisol concentrations in feces and saliva in woolly (n=27 and spider monkeys (n=61. The research was conducted in three studies: the first investigated spider monkeys in the United States, the second investigated spider monkeys within Europe, and the third investigated woolly monkeys within Europe. Fecal cortisol in spider monkeys in US zoos varied (P=.07 from 30 to 66 ng/g. The zoo with the highest fecal cortisol also had the highest salivary cortisol (P≤.05. For European zoos, fecal cortisol differed between zoos for both spider and woolly monkeys (P≤.05. Spider monkeys had higher fecal cortisol than woolly monkeys (P≤.05. Zoos with the highest dietary carbohydrates, sugars, glucose, and fruit had the highest cortisol. Cortisol was highest for zoos that did not meet crude protein requirements and fed the lowest percentage of complete feeds and crude fiber. Differences among zoos in housing and diets may increase animal stress. The lifespan and reproductive success of captive primates could improve if stressors are reduced and dietary nutrients optimized.

  6. Geophagy in brown spider monkeys (Ateles hybridus) in a lowland tropical rainforest in Colombia.

    Science.gov (United States)

    Link, Andres; de Luna, Ana Gabriela; Arango, Ricardo; Diaz, Maria Clara

    2011-01-01

    Spider monkeys and howler monkeys are the only Neotropical primates that eat soil from mineral licks. Not all species within these genera visit mineral licks, and geophagy has been restricted to populations of Ateles belzebuth belzebuth,Ateles belzebuth chamek and Alouatta seniculus in western Amazonian rainforests. With the aid of a camera trap we studied the visitation patterns of a group of brown spider monkeys (Ateles hybridus) to a mineral lick at Serrania de Las Quinchas, in Colombia. Spider monkeys visited the lick frequently throughout the year, with a monthly average of 21.7 ± 7.2 visits per 100 days of camera trapping (n = 14 months). Spider monkeys visited the mineral lick almost always on days with no rain, or very little (<3 mm) rain, suggesting that proximate environmental variables might determine spider monkeys' decisions to come to the ground at the licks. This study expands the geographical occurrence of mineral lick use by spider monkeys providing additional data for future assessments on the biogeographical correlates of mineral lick use by platyrrhines. PMID:21494049

  7. Tactile learning by a whip spider, Phrynus marginemaculatus C.L. Koch (Arachnida, Amblypygi).

    Science.gov (United States)

    Santer, Roger D; Hebets, Eileen A

    2009-04-01

    The ability of animals to learn and remember underpins many behavioural actions and can be crucial for survival in certain contexts, for example in finding and recognising a habitual refuge. The sensory cues that an animal learns in such situations are to an extent determined by its own sensory specialisations. Whip spiders (Arachnida, Amblypygi) are nocturnal and possess uniquely specialised sensory systems that include elongated 'antenniform' forelegs specialised for use as chemo- and mechanosensory feelers. We tested the tactile learning abilities of the whip spider Phrynus marginemaculatus in a maze learning task with two tactile cues of different texture--one associated with an accessible refuge, and the other with an inaccessible refuge. Over ten training trials, whip spiders got faster and more accurate at finding the accessible refuge. During a subsequent test trial where both refuges were inaccessible, whip spiders searched for significantly longer at the tactile cue previously associated with the accessible refuge. Using high-speed cinematography, we describe three distinct antenniform leg movements used by whip spiders during tactile examination. We discuss the potential importance of tactile learning in whip spider behaviour and a possible role for their unique giant sensory neurons in accessing tactile information. PMID:19198849

  8. Association Between Sensitization to Outdoor Spider Mites and Clinical Manifestations of Asthma and Rhinitis in the General Population of Adults

    OpenAIRE

    Kim, Tae-Bum; Kim, Yoon-Keun; Chang, Yoon-Seok; Kim, Sang-Hoon; Hong, Sung-Chul; Jee, Young-Koo; Cho, Sang-Heon; Min, Kyung-Up; Kim, You-Young

    2006-01-01

    It has been demonstrated that spider mites such as the two-spotted spider mite (Tetranychus urticae) are important allergens for fruit farmers. A total of 2,467 adults (795 metropolitan urban, 788 non-metropolitan urban, and 884 rural subjects) were enrolled. They responded to the questionnaire, and underwent methacholine bronchial provocation tests as well as skin prick tests to locally common aeroallergens including the two-spotted spider mite. The prevalences of asthma and rhinitis as repo...

  9. The effect of ageing on the mechanical properties of the silk of the bridge spider Larinioides cornutus (Clerck, 1757)

    OpenAIRE

    Emiliano Lepore; Marco Isaia; Stefano Mammola; Nicola Pugno

    2016-01-01

    Spider silk is regarded as one of the best natural polymer fibers especially in terms of low density, high tensile strength and high elongation until breaking. Since only a few bio-engineering studies have been focused on spider silk ageing, we conducted nano-tensile tests on the vertical naturally spun silk fibers of the bridge spider Larinioides cornutus (Clerck, 1757) (Arachnida, Araneae) to evaluate changes in the mechanical properties of the silk (ultimate stress and strain, Young’s modu...

  10. SVM-Based Prediction of Propeptide Cleavage Sites in Spider Toxins Identifies Toxin Innovation in an Australian Tarantula

    OpenAIRE

    Wong, Emily S. W.; Hardy, Margaret C.; David Wood; Timothy Bailey; Glenn F. King

    2013-01-01

    Spider neurotoxins are commonly used as pharmacological tools and are a popular source of novel compounds with therapeutic and agrochemical potential. Since venom peptides are inherently toxic, the host spider must employ strategies to avoid adverse effects prior to venom use. It is partly for this reason that most spider toxins encode a protective proregion that upon enzymatic cleavage is excised from the mature peptide. In order to identify the mature toxin sequence directly from toxin tran...

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

    Directory of Open Access Journals (Sweden)

    Masahiro (Mh. Osakabe

    2009-01-01

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

  12. Mapping Learning Outcomes and Assignment Tasks for SPIDER Activities

    Directory of Open Access Journals (Sweden)

    Lyn Brodie

    2011-05-01

    Full Text Available Modern engineering programs have to address rapidly changing technical content and have to enable students to develop transferable skills such as critical evaluation, communication skills and lifelong learning. This paper introduces a combined learning and assessment activity that provides students with opportunities to develop and practice their soft skills, but also extends their theoretical knowledge base. Key tasks included self directed inquiry, oral and written communication as well as peer assessment. To facilitate the SPIDER activities (Select, Prepare and Investigate, Discuss, Evaluate, Reflect, a software tool has been implemented in the learning management system Moodle. Evidence shows increased student engagement and better learning outcomes for both transferable as well as technical skills. The study focuses on generalising the relationship between learning outcomes and assignment tasks as well as activities that drive these tasks. Trail results inform the approach. Staff evaluations and their views of assignments and intended learning outcomes also supported this analysis.

  13. Climate change and sexual size dimorphism in an Arctic spider.

    Science.gov (United States)

    Høye, Toke Thomas; Hammel, Jörg U; Fuchs, Thomas; Toft, Søren

    2009-08-23

    Climate change is advancing the onset of the growing season and this is happening at a particularly fast rate in the High Arctic. However, in most species the relative fitness implications for males and females remain elusive. Here, we present data on 10 successive cohorts of the wolf spider Pardosa glacialis from Zackenberg in High-Arctic, northeast Greenland. We found marked inter-annual variation in adult body size (carapace width) and this variation was greater in females than in males. Earlier snowmelt during both years of its biennial maturation resulted in larger adult body sizes and a skew towards positive sexual size dimorphism (females bigger than males). These results illustrate the pervasive influence of climate on key life-history traits and indicate that male and female responses to climate should be investigated separately whenever possible. PMID:19435831

  14. Ecology and multilevel selection explain aggression in spider colonies.

    Science.gov (United States)

    Biernaskie, Jay M; Foster, Kevin R

    2016-08-01

    Progress in sociobiology continues to be hindered by abstract debates over methodology and the relative importance of within-group vs. between-group selection. We need concrete biological examples to ground discussions in empirical data. Recent work argued that the levels of aggression in social spider colonies are explained by group-level adaptation. Here, we examine this conclusion using models that incorporate ecological detail while remaining consistent with kin- and multilevel selection frameworks. We show that although levels of aggression are driven, in part, by between-group selection, incorporating universal within-group competition provides a striking fit to the data that is inconsistent with pure group-level adaptation. Instead, our analyses suggest that aggression is favoured primarily as a selfish strategy to compete for resources, despite causing lower group foraging efficiency or higher risk of group extinction. We argue that sociobiology will benefit from a pluralistic approach and stronger links between ecologically informed models and data. PMID:27264438

  15. New records of spider wasps (Hymenoptera, Pompilidae from Colombia

    Directory of Open Access Journals (Sweden)

    Ana Castro Huertas

    2014-09-01

    Full Text Available New records of genera and species of spider wasps (Hymenoptera: Pompilidae from Colombia are provided. Agenioideus, Cryptocheilus, Evagetes, Mystacagenia, and Xerochares are newly recorded genera from Colombia. Nineteen species are first recorded from Colombia: Aimatocare vitrea (Fox; Ageniella azteca (Cameron; Ageniella curtipinus (Cameron; Ageniella fallax (Arlé; Ageniella hirsuta Banks; Ageniella pilifrons (Cameron; Ageniella pretiosa Banks; Ageniella sanguinolenta (Smith; Ageniella zeteki (Banks; Agenioideus birkmanni (Banks; Aporus (Aporus cuzco Evans; Aporus (Cosmiaporus diverticulus (Fox; Aporus (Notoplaniceps canescens Smith; Euplaniceps exilis (Banks; Euplaniceps herbertii (Fox; Irenangelus clarus Evans; Mystacagenia bellula Evans; Phanochilus nobilitatus (Smith and Xerochares expulsus Schulz. The following species and genera have their occurence ranges expanded for South America: Ageniella azteca (Cameron; Ageniella zeteki (Banks; Agenioideus birkmanni (Banks; and Xerochares expulsus Schulz; Cryptocheilus Panzer; and Xerochares Evans.

  16. No discrimination against previous mates in a sexually cannibalistic spider

    Science.gov (United States)

    Fromhage, Lutz; Schneider, Jutta M.

    2005-09-01

    In several animal species, females discriminate against previous mates in subsequent mating decisions, increasing the potential for multiple paternity. In spiders, female choice may take the form of selective sexual cannibalism, which has been shown to bias paternity in favor of particular males. If cannibalistic attacks function to restrict a male's paternity, females may have little interest to remate with males having survived such an attack. We therefore studied the possibility of female discrimination against previous mates in sexually cannibalistic Argiope bruennichi, where females almost always attack their mate at the onset of copulation. We compared mating latency and copulation duration of males having experienced a previous copulation either with the same or with a different female, but found no evidence for discrimination against previous mates. However, males copulated significantly shorter when inserting into a used, compared to a previously unused, genital pore of the female.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    Foraging by intraspecific kleptoparasitism is widespread among animal taxa. Most kleptoparasitic interactions are considered facultative, and can be influenced by life history stage and trade-offs with other activities such as mate searching. Trade-offs with mating strategies are often sex specific......, 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...... behaviour from hunting to kleptoparasitism in males, males preferred to feed on dead (freshly killed) prey while females preferred live prey. Furthermore, males experienced a decline in prey capture rate compared with females and juveniles. Kleptoparasitism in males was accompanied by inspection of female...

  18. Glutamatergic postsynaptic block by Pamphobeteus spider venoms in crayfish.

    Science.gov (United States)

    Araque, A; Ferreira, W; Lucas, S; Buño, W

    1992-01-31

    The effects of toxins from venom glands of two south american spiders (Pamphobeteus platyomma and P. soracabae) on glutamatergic excitatory synaptic transmission were studied in the neuromuscular junction of the opener muscle of crayfish. The toxins selectively and reversibly blocked both excitatory postsynaptic currents and potentials in a dose-dependent manner. They also reversibly abolished glutamate-induced postsynaptic membrane depolarization. They had no effect on resting postsynaptic membrane conductance nor on postsynaptic voltage-gated currents. The synaptic facilitation and the frequency of miniature postsynaptic potentials were unaffected by the toxins, indicating that presynaptic events were not modified. Picrotoxin, a selective antagonist of the gamma-aminobutyric acid (GABA)A receptor, did not modify toxin effects. We conclude that both toxins specifically block the postsynaptic glutamate receptor-channel complex. PMID:1319261

  19. EFFECT OF THE SPIDER PEUCETIA VIRIDANS (OXYOPIDAE) ON FLORAL VISITORS AND SEED SET OF CNIDOSCOLUS MULTILOBUS (EUPHORBIACEAE)

    OpenAIRE

    Angélica M. Arango; Jorge López-Portillo; Victor Parra-Tabla; Laura T. Hernández-Salazar; Jorge E. Morales-Mávil; Victor Rico-Gray

    2012-01-01

    We studied the interaction between the plant Cnidoscolus multilobus, its floral visitors and the predator spider Peucetia viridans. The diet of P. viridans was composed exclusively of arthropods (spiders 32%, insects 68%). Body length of prey was 5.9 ± 1.0 mm, and prey size range was 11.0 ± 0.4 mm (i.e. 0.14-1.3 times larger than the spider). Based on feeding frequency and time available for prey capture and feeding, one spider may capture up to 3.9 prey items per day, depending on the time o...

  20. David and Goliath: potent venom of an ant-eating spider (Araneae) enables capture of a giant prey

    Science.gov (United States)

    Pekár, Stano; Šedo, Onřej; Líznarová, Eva; Korenko, Stanislav; Zdráhal, Zdeněk

    2014-07-01

    It is rare to find a true predator that repeatedly and routinely kills prey larger than itself. A solitary specialised ant-eating spider of the genus Zodarion can capture a relatively giant prey. We studied the trophic niche of this spider species and investigated its adaptations (behavioural and venomic) that are used to capture ants. We found that the spider captures mainly polymorphic Messor arenarius ants. Adult female spiders captured large morphs while tiny juveniles captured smaller morphs, yet in both cases ants were giant in comparison with spider size. All specimens used an effective prey capture strategy that protected them from ant retaliation. Juvenile and adult spiders were able to paralyse their prey using a single bite. The venom glands of adults were more than 50 times larger than those of juvenile spiders, but the paralysis latency of juveniles was 1.5 times longer. This suggests that this spider species possesses very potent venom already at the juvenile stage. Comparison of the venom composition between juvenile and adult spiders did not reveal significant differences. We discovered here that specialised capture combined with very effective venom enables the capture of giant prey.

  1. Traditions in spider monkeys are biased towards the social domain.

    Directory of Open Access Journals (Sweden)

    Claire J Santorelli

    Full Text Available Cross-site comparison studies of behavioral variation can provide evidence for traditions in wild species once ecological and genetic factors are excluded as causes for cross-site differences. These studies ensure behavior variants are considered within the context of a species' ecology and evolutionary adaptations. We examined wide-scale geographic variation in the behavior of spider monkeys (Ateles geoffroyi across five long-term field sites in Central America using a well established ethnographic cross-site survey method. Spider monkeys possess a relatively rare social system with a high degree of fission-fusion dynamics, also typical of chimpanzees (Pan troglodytes and humans (Homo sapiens. From the initial 62 behaviors surveyed 65% failed to meet the necessary criteria for traditions. The remaining 22 behaviors showed cross-site variation in occurrence ranging from absent through to customary, representing to our knowledge, the first documented cases of traditions in this taxon and only the second case of multiple traditions in a New World monkey species. Of the 22 behavioral variants recorded across all sites, on average 57% occurred in the social domain, 19% in food-related domains and 24% in other domains. This social bias contrasts with the food-related bias reported in great ape cross-site comparison studies and has implications for the evolution of human culture. No pattern of geographical radiation was found in relation to distance across sites. Our findings promote A. geoffroyi as a model species to investigate traditions with field and captive based experiments and emphasize the importance of the social domain for the study of animal traditions.

  2. Responses of ground-dwelling spiders to four hedgerow species on sloped agricultural fields in Southwest

    Institute of Scientific and Technical Information of China (English)

    Yuhong Wu; Qingnian Cai; Chaowen Lin; Yibing Chen; Yuying Li; Xu Cheng

    2009-01-01

    Spiders are important predators in aeroecosystems and contribute to the control of agricultural nect nnnulatinns.Hahitat manage-ment such as the creation of new semi-natural habitats around or within fields enhances spider abundance and species diversity.Using pitfall traps,we investigated the effects of four hedgerow plant svecies.which serve as undisturhed and permanent semi-narimal habitats,on ground-dwelling spider activity density(a parameter of nonulation density and relative activitv)and species richness.Samples were ollected over two winter wheat and two summer maize growing seasons druing 2005-2007 in trial field 1(slope gradient of 20%)and field 2(slope gradient of 12%)at the Ziyane Experimental Site in Sichuan Province,China.The hedgerow species evaluated were Amorpha fruticosa(field 1).Vetiveria zizanioides(field 1),EulahODsis binata (field 2),and Afediraon sativa(field 2).CnmnareA to rnntrnl plots,hedgerow plots had significantly higher activity density and species richness of ground-dwelling spiders within strips in both fields 1 and 2 during the wheat growing season.The presence of hedgerow strins did not augment the activity density and species richness of ground-dwelling spiders within the crop fields during the wheat or maize growing seasons.The ground-dwelling spider activity density within hedgerow strips was significantly higher in the Vetiveria than in the AmorDha nlots and in the Medicago than in the Eulaliopsis plots,and the species richness was significantly higher in the Vetiveria than in the Amornha plots during the wheat season. Our results suggest that hedgerows may serve as important overwinterine sites for ground-dwelling spiders durinjthe wheat growing season.In addition,the diversification of agroecosystems by using hedgerow strips may be a viable strategy for maintaining ground-dwelling spider populations in agricultural areas.However,ground-dwelling spiders did not move into adiacent crop fields;therefore,future work should

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

    International Nuclear Information System (INIS)

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

  4. 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.

  5. 'Natural experiment' demonstrates top-down control of spiders by birds on a landscape level.

    Directory of Open Access Journals (Sweden)

    Haldre Rogers

    Full Text Available The combination of small-scale manipulative experiments and large-scale natural experiments provides a powerful approach for demonstrating the importance of top-down trophic control on the ecosystem scale. The most compelling natural experiments have come from studies examining the landscape-scale loss of apex predators like sea otters, wolves, fish and land crabs. Birds are dominant apex predators in terrestrial systems around the world, yet all studies on their role as predators have come from small-scale experiments; the top-down impact of bird loss on their arthropod prey has yet to be examined at a landscape scale. Here, we use a unique natural experiment, the extirpation of insectivorous birds from nearly all forests on the island of Guam by the invasive brown tree snake, to produce the first assessment of the impacts of bird loss on their prey. We focused on spiders because experimental studies showed a consistent top-down effect of birds on spiders. We conducted spider web surveys in native forest on Guam and three nearby islands with healthy bird populations. Spider web densities on the island of Guam were 40 times greater than densities on islands with birds during the wet season, and 2.3 times greater during the dry season. These results confirm the general trend from manipulative experiments conducted in other systems however, the effect size was much greater in this natural experiment than in most manipulative experiments. In addition, bird loss appears to have removed the seasonality of spider webs and led to larger webs in at least one spider species in the forests of Guam than on nearby islands with birds. We discuss several possible mechanisms for the observed changes. Overall, our results suggest that effect sizes from smaller-scale experimental studies may significantly underestimate the impact of bird loss on spider density as demonstrated by this large-scale natural experiment.

  6. [Spider diversity in cultures of Citrus sinensis (Rutaceae) in Corrientes province, Argentina].

    Science.gov (United States)

    Avalos, Gilberto; Bar, Maria Esther; Oscherov, Elena Beatriz; González, Alda

    2013-09-01

    Spiders are predators that reduce insect pest populations in agroecosystems. In spite that the presence of spider assemblages has been described in different crop plants, no reports have been done for Citrus species in Argentina. We studied the spider community associated with cultures of Citrus sinensis in the province of Corrientes, Argentina, in two plots (AM1 irrigated and AM2 unirrigated) of 0.82 hectares each. Spiders were collected monthly by using pitfall traps, hand capture, agitation of foliage and sieving of soil litter. A total of 7174 specimens were collected (33 families, 44 genera and 200 species/morphospecies). The AM1 recorded 3811 individuals (33 families, 179 species/morphospecies) and AM2 3363 individuals (31 families, 174 species/morphospecies). November, December and January showed the highest abundance in both plots. A total of 70% of collected spiders were juveniles. Eight families were the most abundant and represented 75% of spiders collected in both plots, the largest being Lycosidae. We identified eight guilds in both plots, for which the ground runners resulted the most abundant (AM1 n = 1341, s=39, n=999 AM2, s = 33), followed by orb weavers (AM1 n = 637, s = 36; AM2 n = 552, s = 33), the stalkers (AM1 n = 471, s = 43, AM2 n = 453, s = 47) and the space web-builders (AM1 n = 446, s = 23; AM2 n = 342, s = 25). The analysis of alpha diversity in both plots (AM1H' = 4.161, J' = 0.802; AM2 H' = 4.184, J' = 0.811) showed no significant differences (t = 1.083 p = 0.279). The linear dependences model was the one with the best fit results, where the species observed were more than estimated. Clench model estimated 90.9% of the spiders observed in the unit with irrigation and 90.6% in the unit without irrigation. PMID:24027921

  7. A comparative analysis of the morphology and evolution of permanent sperm depletion in spiders.

    Directory of Open Access Journals (Sweden)

    Peter Michalik

    Full Text Available Once thought to be energetically cheap and easy to produce, empirical work has shown that sperm is a costly and limited resource for males. In some spider species, there is behavioral evidence that sperm are permanently depleted after a single mating. This extreme degree of mating investment appears to co-occur with other reproductive strategies common to spiders, e.g. genital mutilation and sexual cannibalism. Here we corroborate that sperm depletion in the golden orb-web spider Nephila clavipes is permanent by uncovering its mechanistic basis using light and electron microscopy. In addition, we use a phylogeny-based statistical analysis to test the evolutionary relationships between permanent sperm depletion (PSD and other reproductive strategies in spiders. Male testes do not produce sperm during adulthood, which is unusual in spiders. Instead, spermatogenesis is nearly synchronous and ends before the maturation molt. Testis size decreases as males approach their maturation molt and reaches its lowest point after sperm is transferred into the male copulatory organs (pedipalps. As a consequence, the amount of sperm available to males for mating is limited to the sperm contained in the pedipalps, and once it is used, males lose their ability to fertilize eggs. Our data suggest that PSD has evolved independently at least three times within web-building spiders and is significantly correlated with the evolution of other mating strategies that limit males to monogamy, including genital mutilation and sexual cannibalism. We conclude that PSD may be an energy-saving adaptation in species where males are limited to monogamy. This could be particularly important in web-building spiders where extreme sexual size dimorphism results in large, sedentary females and small, searching males who rarely feed as adults and are vulnerable to starvation. Future work will explore possible energetic benefits and the evolutionary lability of PSD relative to other

  8. The new Andean jumping spider genus Urupuyu and its placement within a revised classification of the Amycoida (Araneae: Salticidae).

    Science.gov (United States)

    Ruiz, Gustavo R S; Maddison, Wayne P

    2015-01-01

    Urupuyu gen. nov. is described for three new species of small black jumping spiders from the cloud forests of Ecuador: Urupuyu antisana sp. nov. (type species), U. edwardsi sp. nov., and U. occidentale sp. nov. Phylogenetic analyses with DNA sequences (28S, actin 5C, wingless, 16SND1 and CO1) indicate Urupuyu is closely related to the huriine amycoids Hurius and Scoturius, a placement also supported by morphological traits. Our phylogenetic analysis serves to clarify the relationships within the Amycoida in general, leading to our proposing a revised classification for the group, with subfamilies Gophoinae, Sitticinae, Bredinae subfam. nov., Scopocirinae, Thiodininae, Sarindinae, Huriinae, Simonellinae, and Amycinae. We confirm the marpissine-like Breda belongs within the Amycoida. The phylogeny implies that ant mimicry has evolved at least twice (simonellines and sarindines) and probably a third time (Atomosphyrus in the thiodinines) within the Amycoida. The following new synonymies are proposed for suprageneric names: Hyetusseae Simon, 1903 and Arachnomureae Mello-Leitão, 1917 = Thiodininae Simon, 1901; Zunigeae Simon, 1901 = Sarindinae Simon, 1901; Synemosynae Banks, 1892 = Simonellinae Peckham, Peckham & Wheeler, 1888; Magoninae Petrunkevitch, 1928 = Amycinae F.O.P.-Cambridge, 1900. PMID:26624665

  9. The relation among variables of mental health and cognition in widowed elders / A relação entre variáveis de saúde mental e cognição em idosos viúvos

    Directory of Open Access Journals (Sweden)

    Clarissa Marceli Trentini

    2009-01-01

    Full Text Available To assess the cognitive abilities of widowed elders, a total sample of 34 elders (who have lost their spouses in the last 12 months was identified among elders in Veranópolis-RS and 30 of them accepted to participate in the study. The control group was composed by 30 married subjects paired according to gender, age and level of education. The instruments used were: Measure Questionnaire of Memory Loss Complaints; Verbal Fluency - animal category; Mini-Mental State Examination (MMSE; Free and Cued Selective Reminding Test; Digit subtest; Geriatric Depression Scales and Bereavement Phenomenology Questionnaire. Widowed elders had significantly more depressive symptoms and more points on the bereavement scale. However, there was no significant difference between the means of cognitive performance of widowed or married elders. In the census, the choice of widowhood as a selection criterion instead of bereavement (self reported might have influenced the lack of association between widowhood and cognitive dysfunction, among other aspects.

  10. Japanese monkeys (Macaca fuscata) quickly detect snakes but not spiders: Evolutionary origins of fear-relevant animals.

    Science.gov (United States)

    Kawai, Nobuyuki; Koda, Hiroki

    2016-08-01

    Humans quickly detect the presence of evolutionary threats through visual perception. Many theorists have considered humans to be predisposed to respond to both snakes and spiders as evolutionarily fear-relevant stimuli. Evidence supports that human adults, children, and snake-naive monkeys all detect pictures of snakes among pictures of flowers more quickly than vice versa, but recent neurophysiological and behavioral studies suggest that spiders may, in fact, be processed similarly to nonthreat animals. The evidence of quick detection and rapid fear learning by primates is limited to snakes, and no such evidence exists for spiders, suggesting qualitative differences between fear of snakes and fear of spiders. Here, we show that snake-naive Japanese monkeys detect a single snake picture among 8 nonthreat animal pictures (koala) more quickly than vice versa; however, no such difference in detection was observed between spiders and pleasant animals. These robust differences between snakes and spiders are the most convincing evidence that the primate visual system is predisposed to pay attention to snakes but not spiders. These findings suggest that attentional bias toward snakes has an evolutionary basis but that bias toward spiders is more due to top-down, conceptually driven effects of emotion on attention capture. (PsycINFO Database Record PMID:27078076

  11. Multiple endosymbiont infections and reproductive manipulations in a linyphiid spider population.

    Science.gov (United States)

    Curry, M M; Paliulis, L V; Welch, K D; Harwood, J D; White, J A

    2015-08-01

    In many arthropods, maternally inherited endosymbiotic bacteria can increase infection frequency by manipulating host reproduction. Multiple infections of different bacteria in a single host population are common, yet few studies have documented concurrent endosymbiont phenotypes or explored their potential interactions. We hypothesized that spiders might be a particularly useful taxon for investigating endosymbiont interactions, because they are host to a plethora of endosymbiotic bacteria and frequently exhibit multiple infections. We established two matrilines from the same population of the linyphiid spider Mermessus fradeorum and then used antibiotic curing and controlled mating assays to demonstrate that each matriline was subject to a distinct endosymbiotic reproductive manipulation. One matriline was co-infected with Rickettsia and Wolbachia and produced offspring with a radical female bias. Antibiotic treatment eliminated both endosymbionts and restored an even sex ratio to subsequent generations. Chromosomal and fecundity observations suggest a feminization mechanism. In the other matriline, a separate factorial mating assay of cured and infected spiders demonstrated strong cytoplasmic incompatibility (CI) induced by a different strain of Wolbachia. However, males with this Wolbachia induced only mild CI when mated with the Rickettsia-Wolbachia females. In a subsequent survey of a field population of M. fradeorum, we detected these same three endosymbionts infecting 55% of the spiders in almost all possible combinations, with nearly half of the infected spiders exhibiting multiple infection. Our results suggest that a dynamic network of endosymbionts may interact both within multiply infected hosts and within a population subject to multiple strong reproductive manipulations. PMID:25899011

  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. 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.

  14. Tracking a medically important spider: climate change, ecological niche modeling, and the brown recluse (Loxosceles reclusa).

    Science.gov (United States)

    Saupe, Erin E; Papes, Monica; Selden, Paul A; Vetter, Richard S

    2011-01-01

    Most spiders use venom to paralyze their prey and are commonly feared for their potential to cause injury to humans. In North America, one species in particular, Loxosceles reclusa (brown recluse spider, Sicariidae), causes the majority of necrotic wounds induced by the Araneae. However, its distributional limitations are poorly understood and, as a result, medical professionals routinely misdiagnose brown recluse bites outside endemic areas, confusing putative spider bites for other serious conditions. To address the issue of brown recluse distribution, we employ ecological niche modeling to investigate the present and future distributional potential of this species. We delineate range boundaries and demonstrate that under future climate change scenarios, the spider's distribution may expand northward, invading previously unaffected regions of the USA. At present, the spider's range is centered in the USA, from Kansas east to Kentucky and from southern Iowa south to Louisiana. Newly influenced areas may include parts of Nebraska, Minnesota, Wisconsin, Michigan, South Dakota, Ohio, and Pennsylvania. These results illustrate a potential negative consequence of climate change on humans and will aid medical professionals in proper bite identification/treatment, potentially reducing bite misdiagnoses. PMID:21464985

  15. Tracking a medically important spider: climate change, ecological niche modeling, and the brown recluse (Loxosceles reclusa.

    Directory of Open Access Journals (Sweden)

    Erin E Saupe

    Full Text Available Most spiders use venom to paralyze their prey and are commonly feared for their potential to cause injury to humans. In North America, one species in particular, Loxosceles reclusa (brown recluse spider, Sicariidae, causes the majority of necrotic wounds induced by the Araneae. However, its distributional limitations are poorly understood and, as a result, medical professionals routinely misdiagnose brown recluse bites outside endemic areas, confusing putative spider bites for other serious conditions. To address the issue of brown recluse distribution, we employ ecological niche modeling to investigate the present and future distributional potential of this species. We delineate range boundaries and demonstrate that under future climate change scenarios, the spider's distribution may expand northward, invading previously unaffected regions of the USA. At present, the spider's range is centered in the USA, from Kansas east to Kentucky and from southern Iowa south to Louisiana. Newly influenced areas may include parts of Nebraska, Minnesota, Wisconsin, Michigan, South Dakota, Ohio, and Pennsylvania. These results illustrate a potential negative consequence of climate change on humans and will aid medical professionals in proper bite identification/treatment, potentially reducing bite misdiagnoses.

  16. Immobilizing and lethal effects of spider venoms on the cockroach and the common mealbeetle.

    Science.gov (United States)

    Friedel, T; Nentwig, W

    1989-01-01

    Immobilizing and lethal effects of the venoms obtained from six spider species (Brachypelma albopilosum, Atrax robustus, Cupiennius salei, Selenops mexicanus, Tegenaria atrica, Argiope bruennichi) were tested on Blatta orientalis (cockroach) and Tenebrio molitor (common mealbeetle). The immobilizing effects were quantified by measuring insect locomotor activity in circle arenas observed over 72 hr after venom injection. Both insect species showed cramps, quivering and jerking of the limbs as well as flaccid paralysis after venom injection. Through relative toxicity of the venoms tested is the same in T. molitor and B. orientalis, T. molitor is absolutely less sensitive to spider venoms. The effects on locomotor activity show time characteristics specific for each venom. A dependence of the venom paralyzing effects on insect locomotor activity, low intensity of the initial excitatory phase of the venom effects and partial recovery of the insects was found with A. bruennichi and T. atrica venom. The maximal venom yields of A. bruennichi and S. mexicanus are not lethal to B. orientalis, indicating that the mere immobilizing effects of spider venoms are far more crucial to prey capture than their lethal effects. The contribution of a variety of differently acting neurotoxic components in spider venoms to the observed venom effects on insects and the significance of the venoms in spider nutrition, hunting behaviour and ecology are discussed. PMID:2728023

  17. Inhibition of Return in Fear of Spiders: Discrepant Eye Movement and Reaction Time Data

    Directory of Open Access Journals (Sweden)

    Elisa Berdica

    2014-01-01

    Full Text Available Inhibition of return (IOR refers to a bias against returning the attention to a previously attended location. As a foraging facilitator it is thought to facilitate systematic visual search. With respect to neutral stimuli, this is generally thought to be adaptive, but when threatening stimuli appear in our environment, such a bias may be maladaptive. This experiment investigated the influence of phobia-related stimuli on the IOR effect using a discrimination task. A sample of 50 students (25 high, 25 low in spider fear completed an IOR task including schematic representations of spiders or butterflies as targets. Eye movements were recorded and to assess discrimination among targets, participants indicated with button presses if targets were spiders or butterflies. Reaction time data did not reveal a significant IOR effect but a significant interaction of group and target; spider fearful participants were faster to respond to spider targets than to butterflies. Furthermore, eye-tracking data showed a robust IOR effect independent of stimulus category. These results offer a more comprehensive assessment of the motor and oculomotor factors involved in the IOR effect.

  18. fMRI neurofeedback facilitates anxiety regulation in females with spider phobia

    Directory of Open Access Journals (Sweden)

    Anna eZilverstand

    2015-06-01

    Full Text Available Background: Spider phobics show an exaggerated fear response when encountering spiders. This fear response is aggravated by negative and irrational beliefs about the feared object. Cognitive reappraisal can target these beliefs, and therefore has a fear regulating effect. The presented study investigated if neurofeedback derived from functional magnetic resonance imaging (fMRI would facilitate anxiety regulation by cognitive reappraisal, using spider phobia as a model of anxiety disorders. Feedback was provided based on activation in left dorsolateral prefrontal cortex and right insula, as indicators of engagement and regulation success, respectively.Methods: Eighteen female spider phobics participated in a randomized, controlled, single-blinded study. All participants completed a training session in the MRI scanner. Participants assigned to the neurofeedback condition were instructed to shape their regulatory strategy based on the provided feedback. Participants assigned to the control condition were asked to adapt their strategy intuitively.Results: Neurofeedback participants exhibited lower anxiety levels than the control group at the end of the training. In addition, only neurofeedback participants achieved down-regulation of insula activation levels by cognitive reappraisal. Group differences became more pronounced over time, supporting learning as a mechanism behind this effect. Importantly, within the neurofeedback group, achieved changes in insula activation levels during training predicted long-term anxiety reduction.Conclusions: The conducted study provides first evidence that fMRI neurofeedback has a facilitating effect on anxiety regulation in spider phobia.

  19. [Diversity of insects captured by weaver spiders (Arachnida: Araneae) in the cocoa agroecosystem in Tabasco, Mexico].

    Science.gov (United States)

    Pérez-de La Cruz, Manuel; Sánchez-Soto, Saúl; Ortíz-García, Carlos F; Zapata-Mata, Raúl; Cruz-Pérez, Aracely de la

    2007-01-01

    The aim of this work was to know the diversity of insects captured by weaver spiders in a plantation of cocoa (Theobroma cacao L.) of 6 ha in the State of Tabasco, Mexico. The study was carried out from July 2004 to June 2005 by means biweekly samples of the insects captured on the spiders webs. The total of 3,041 webs of 54 species of spiders belonging to seven families (Araneidae, Theridiidae, Tetragnathidae, Uloboridae, Pholcidae, Dyctinidae and Linyphiidae) were revised. We found 1,749 specimens belonging to 10 orders of insects, represented by 93 families, the majority of Coleoptera, Diptera and Hemiptera that constituted 74% of the identified families. The biggest number of specimens of all orders was captured by Araneidae, except of Isoptera, whose specimens were captured mainly by the family Theridiidae. The index of diversity (H'), evenness (J') and similarity (Is), applied to know the diversity of families of insects captured among families of spiders, varied from 0.00 to 3.24, 0.00 to 0.81, and 0.04 to 0.522, respectively. We conclude that there is a wide diversity of insects predated by the weaver spiders in the cocoa agroecosystem, and that there are species that can be promising for the biological control of pests. PMID:17420866

  20. Radionic nonuniform black strings

    Science.gov (United States)

    Tamaki, Takashi; Kanno, Sugumi; Soda, Jiro

    2004-01-01

    Nonuniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a nontrivial hair of the black strings. From the brane point of view, the black string appears as the deformed dilatonic black hole which becomes a dilatonic black hole in the single brane limit and reduces to the Reissner-Nordström black hole in the close limit of two-branes. The stability of solutions is demonstrated using catastrophe theory. From the bulk point of view, the black strings are proved to be nonuniform. Nevertheless, the zeroth law of black hole thermodynamics still holds.

  1. Event-related potentials when identifying or color-naming threatening schematic stimuli in spider phobic and non-phobic individuals

    Directory of Open Access Journals (Sweden)

    Musial Frauke

    2006-09-01

    Full Text Available Abstract Background Previous studies revealed increased parietal late positive potentials (LPPs in response to spider pictures in spider phobic individuals. This study searched for basic features of fear-relevant stimuli by investigating whether schematic spider images are sufficient to evoke differential behavioral as well as differential early and late ERP responses in spider phobic, social phobic (as a clinical control group, and non-phobic control participants. Methods Behavioral and electrophysiological correlates of the processing of schematic spider and flower images were investigated while participants performed a color (emotional Stroop and an object identification task. Stimuli were schematic pictures of spiders and flowers matched with respect to constituting visual elements. Results Consistent with previous studies using photographic spider pictures, spider phobic persons showed enhanced LPPs when identifying schematic spiders compared to schematic flowers. In addition, spider phobic individuals showed generally faster responses than the control groups. This effect was interpreted as evidence for an increased general behavioral hypervigilance in this anxiety disorder group. Furthermore, both phobic groups showed enhanced P100 amplitudes compared to controls, which was interpreted as evidence for an increased (cortical hypervigilance for incoming stimuli in phobic patients in general. Finally, all groups showed faster identification of and larger N170 amplitudes in response to schematic spider than flower pictures. This may reflect either a general advantage for fear-relevant compared to neutral stimuli, or might be due to a higher level of expertise in processing schematic spiders as compared to the more artificially looking flower stimuli. Conclusion Results suggest that schematic spiders are sufficient to prompt differential responses in spider-fearful and spider-non-fearful persons in late ERP components. Early ERP components, on

  2. Vertical distribution of spiders associated to Quercus humboldtii and clusia spp. at sanctuary of fauna and flora Iguaque, Colombia

    International Nuclear Information System (INIS)

    the vertical distribution of spiders associated to trees of quercus humboldtii and clusia spp. with different architectural model, was studied at sanctuary of fauna and flora of Iguaque; for this, we selected trees of each architectural model, stratified them each three m in high starting at the base to the canopy of the tree. We took samples in each stratus for 20 min during the day and at night. Also, we took samples in the nearest ground plot (4 m2). We collected 1,261 specimens of 104 morphospecies and 20 families. The most frequent families were theridiidae, salticidae, araneidae, linyphiidae, anyphaenidae, and theridiosomatidae. We observed differences in the spiders' vertical distribution in abundance, richness, composition, time period, and sex ratio, all of them attributable to plant architectures and its stratification. Clusia spider community was the most diverse, quercus spider community was the richest rain, period of time at day, and support availability affected the spiders' composition.

  3. Can ant-eating Zodarion spiders (Araneae: Zodariidae) develop on a diet optimal for euryphagous arthropod predators?

    DEFF Research Database (Denmark)

    Pekar, Stano; Toft, Søren

    2009-01-01

    adaptations may then entail trade-offs in handling and utilization of alternative prey. To investigate behavioural as well as nutritional adaptations and the occurrence of the corresponding trade-offs in two ant-eating spiders of the genus Zodarion [Zodarion atlanticum Pekár & Cardoso and Zodarion germanicum...... (C. L. Koch)], spiders are reared on two diets: ants (i.e. their preferred prey) and fruit flies (i.e. an alternative prey that is nutritionally optimal for euryphagous spiders). Food consumption is observed and several fitness-related life-history parameters are measured. Although spiders readily......, and all of these die during the first two stadia. By contrast, spiders on an ant diet increase dramatically in weight, and develop up to the fourth stadium. These data indicate that fruit flies are not suitable for Zodarion, supporting the hypothesis that there are behavioural and nutritional trade-offs...

  4. Trichobothrial mediation of an aquatic escape response: Directional jumps by the fishing spider, Dolomedes triton, foil frog attacks

    Directory of Open Access Journals (Sweden)

    Robert B. Suter

    2003-07-01

    Full Text Available Fishing spiders (Pisauridae frequent the surfaces of ponds and streams and thereby expose themselves to predation by a variety of aquatic and semi-aquatic vertebrates. To assess the possibility that the impressive jumps of fishing spiders from the water surface function in evading attacks by frogs, attacks by bullfrogs (Rana catesbiana and green frogs (R. clamitans on Dolomedes triton were studied. Both the attack dynamics of the frogs and the evasive behaviors of the spiders were recorded at 250 frames per second. A freeze-dried bullfrog, propelled toward spiders with acceleration, posture, and position that approximated the natural attack posture and dynamics, was used to assess the spiders' behavior. Qualitatively, the spiders responded to these mock-attacks just as they had to attacks by live frogs: jumping (N=29 jumps, 56.9% of instances, rearing the legs nearest the attacking frog (N=15, 29.4%, or showing no visible response (N=7, 13.7%. Spiders that jumped always did so away (in the vertical plane from the attack (mean =137° vs. vertical at 90° or horizontally toward the frog at 0°. The involvement of the trichobothria (leg hairs sensitive to air movements, and the eyes as sensory mediators of the evasion response was assessed. Spiders with deactivated trichobothria were significantly impaired relative to intact and sham-deactivated spiders, and relative to spiders in total darkness. Thus, functional trichobothria, unlike the eyes, are both necessary and sufficient mediators of the evasion response. Measurements of air flow during frog attacks suggest that an exponential rise in flow velocity is the airborne signature of an attack.

  5. SVM-based prediction of propeptide cleavage sites in spider toxins identifies toxin innovation in an Australian tarantula.

    Directory of Open Access Journals (Sweden)

    Emily S W Wong

    Full Text Available Spider neurotoxins are commonly used as pharmacological tools and are a popular source of novel compounds with therapeutic and agrochemical potential. Since venom peptides are inherently toxic, the host spider must employ strategies to avoid adverse effects prior to venom use. It is partly for this reason that most spider toxins encode a protective proregion that upon enzymatic cleavage is excised from the mature peptide. In order to identify the mature toxin sequence directly from toxin transcripts, without resorting to protein sequencing, the propeptide cleavage site in the toxin precursor must be predicted bioinformatically. We evaluated different machine learning strategies (support vector machines, hidden Markov model and decision tree and developed an algorithm (SpiderP for prediction of propeptide cleavage sites in spider toxins. Our strategy uses a support vector machine (SVM framework that combines both local and global sequence information. Our method is superior or comparable to current tools for prediction of propeptide sequences in spider toxins. Evaluation of the SVM method on an independent test set of known toxin sequences yielded 96% sensitivity and 100% specificity. Furthermore, we sequenced five novel peptides (not used to train the final predictor from the venom of the Australian tarantula Selenotypus plumipes to test the accuracy of the predictor and found 80% sensitivity and 99.6% 8-mer specificity. Finally, we used the predictor together with homology information to predict and characterize seven groups of novel toxins from the deeply sequenced venom gland transcriptome of S. plumipes, which revealed structural complexity and innovations in the evolution of the toxins. The precursor prediction tool (SpiderP is freely available on ArachnoServer (http://www.arachnoserver.org/spiderP.html, a web portal to a comprehensive relational database of spider toxins. All training data, test data, and scripts used are available from

  6. SVM-based prediction of propeptide cleavage sites in spider toxins identifies toxin innovation in an Australian tarantula.

    Science.gov (United States)

    Wong, Emily S W; Hardy, Margaret C; Wood, David; Bailey, Timothy; King, Glenn F

    2013-01-01

    Spider neurotoxins are commonly used as pharmacological tools and are a popular source of novel compounds with therapeutic and agrochemical potential. Since venom peptides are inherently toxic, the host spider must employ strategies to avoid adverse effects prior to venom use. It is partly for this reason that most spider toxins encode a protective proregion that upon enzymatic cleavage is excised from the mature peptide. In order to identify the mature toxin sequence directly from toxin transcripts, without resorting to protein sequencing, the propeptide cleavage site in the toxin precursor must be predicted bioinformatically. We evaluated different machine learning strategies (support vector machines, hidden Markov model and decision tree) and developed an algorithm (SpiderP) for prediction of propeptide cleavage sites in spider toxins. Our strategy uses a support vector machine (SVM) framework that combines both local and global sequence information. Our method is superior or comparable to current tools for prediction of propeptide sequences in spider toxins. Evaluation of the SVM method on an independent test set of known toxin sequences yielded 96% sensitivity and 100% specificity. Furthermore, we sequenced five novel peptides (not used to train the final predictor) from the venom of the Australian tarantula Selenotypus plumipes to test the accuracy of the predictor and found 80% sensitivity and 99.6% 8-mer specificity. Finally, we used the predictor together with homology information to predict and characterize seven groups of novel toxins from the deeply sequenced venom gland transcriptome of S. plumipes, which revealed structural complexity and innovations in the evolution of the toxins. The precursor prediction tool (SpiderP) is freely available on ArachnoServer (http://www.arachnoserver.org/spiderP.html), a web portal to a comprehensive relational database of spider toxins. All training data, test data, and scripts used are available from the Spider

  7. The deep phylogeny of jumping spiders (Araneae, Salticidae

    Directory of Open Access Journals (Sweden)

    Wayne Maddison

    2014-09-01

    Full Text Available In order to resolve better the deep relationships among salticid spiders, we compiled and analyzed a molecular dataset of 169 salticid taxa (and 7 outgroups and 8 gene regions. This dataset adds many new taxa to previous analyses, especially among the non-salticoid salticids, as well as two new genes – wingless and myosin heavy chain. Both of these genes, and especially the better sampled wingless, confirm many of the relationships indicated by other genes. The cocalodines are placed as sister to lapsiines, in a broader clade with the spartaeines. Cocalodines, lapsiines, and spartaeines are each supported as monophyletic, though the first two have no known morphological synapomorphies. The lyssomanines appear to be non-monophyletic, of three separate groups: (1 Lyssomanes plus Chinoscopus, (2 Onomastus, and (3 the remainder of Old World species. Several previously-inferred relationships continue to be supported: hisponines as sister to the Salticoida, Amycoida as sister to the remaining Salticoida, and Saltafresia as monophyletic. The relationship of Salticus with Philaeus and relatives is now considered well enough corroborated to move the latter into the subfamily Salticinae. A new clade consisting of the Plexippoida + Aelurilloida + Leptorchesteae + Salticinae is recognized. Nungia is found to be an astioid, and Echeclus, Gedea and Diplocanthopoda to be hasariines. The euophryines are corroborated as monophyletic. The agoriines Agorius and Synagelides are salticoids, within the sister group to amycoids, but their further placement is problematical, perhaps because of their nuclear ribosomal genes’ high GC bias, as also seen in the similarly problematic Eupoa.

  8. Spectroscopic diagnostics for the negative ion RF source SPIDER

    Energy Technology Data Exchange (ETDEWEB)

    Pasqualotto, R., E-mail: roberto.pasqualotto@igi.cnr.i [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, Padova 35127 (Italy); Gazza, E.; Serianni, G.; Zaniol, B.; Agostini, M.; Alfier, A. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, Padova 35127 (Italy)

    2010-11-11

    The negative ion RF source SPIDER, prototype source of the ITER neutral beam injectors, will be built at Consorzio RFX, and it will include a full set of diagnostics, required for safe operation and beam performance optimization. This paper describes the design of spectroscopic diagnostics of both plasma source and accelerated beam. Emission spectroscopy of the plasma source will measure key parameters involved in negative ion (H{sup -} or D{sup -}) formation and recombination processes, such as temperature and density of electrons and of the plasma gas in atomic and molecular form, density of cesium and other impurities and, finally, the H{sup -}/D{sup -} concentration. Absorption spectroscopy, with a cavity ring-down technique, will provide a direct measure of the H{sup -}/D{sup -} density. The extracted beam is then probed by beam emission spectroscopy, to measure the beam homogeneity, divergence and stripping losses. Observing the emission of a selected spectral line with a sufficient number of lines-of-sight will allow a tomographic reconstruction of the two-dimensional beam emission, which is proportional to the beam density.

  9. Universal behaviors as candidate traditions in wild spider monkeys.

    Directory of Open Access Journals (Sweden)

    Claire J Santorelli

    Full Text Available Candidate traditions were documented across three communities of wild spider monkeys (Ateles geoffroyi using an a priori approach to identify behavioral variants and a statistical approach to examine differences in their proportional use. This methodology differs from previous studies of animal traditions, which used retrospective data and relied on the 'exclusion method' to identify candidate traditions. Our a priori approach increased the likelihood that behavior variants with equivalent functions were considered and our statistical approach enabled the proportional use of 'universal' behaviors, i.e., used across all communities, to be examined for the first time in any animal species as candidate traditions. Among universal behaviors we found 14 'community preferred' variants. After considering the extent to which community preferred variants were due to ecological and, to a lesser degree, genetic differences, we concluded that at least six were likely maintained through social learning. Our findings have two main implications: (i tradition repertoires could be larger than assumed from previous studies using the exclusion method; (ii the relative use of universal behavior variants can reinforce community membership.

  10. Silkomics: Insight into the Silk Spinning Process of Spiders.

    Science.gov (United States)

    Dos Santos-Pinto, José Roberto Aparecido; Garcia, Ana Maria Caviquioli; Arcuri, Helen Andrade; Esteves, Franciele Grego; Salles, Heliana Clara; Lubec, Gert; Palma, Mario Sergio

    2016-04-01

    The proteins from the silk-producing glands were identified using both a bottom-up gel-based proteomic approach as well as from a shotgun proteomic approach. Additionally, the relationship between the functions of identified proteins and the spinning process was studied. A total of 125 proteins were identified in the major ampullate, 101 in the flagelliform, 77 in the aggregate, 75 in the tubuliform, 68 in the minor ampullate, and 23 in aciniform glands. On the basis of the functional classification using Gene Ontology, these proteins were organized into seven different groups according to their general function: (i) web silk proteins-spidroins, (ii) proteins related to the folding/conformation of spidroins, (iii) proteins that protect silk proteins from oxidative stress, (iv) proteins involved in fibrillar preservation of silks in the web, (v) proteins related to ion transport into and out of the glands during silk fiber spinning, (vi) proteins involved in prey capture and pre-digestion, and (vii) housekeeping proteins from all of the glands. Thus, a general mechanism of action for the identified proteins in the silk-producing glands from the Nephila clavipes spider was proposed; the current results also indicate that the webs play an active role in prey capture. PMID:26923066

  11. Taxonomic revision of the American spider genus Arachosia (Araneae: Anyphaenidae).

    Science.gov (United States)

    Rubio, Gonzalo D; Ramírez, Martín J

    2015-01-01

    We review the American spider genus Arachosia O.P.-Cambridge, and present a descriptive taxonomic study with a comparative dichotomous key including 21 species, of which seven are newly described (A. avalosi sp. nov., A. carancho sp. nov., A. kapiipeoi sp. nov., A. magna sp. nov., A. monserrate sp. nov., A. pinhalito sp. nov. and A. tungurahua sp. nov.). Four species names are considered nomina dubia: Oxysoma dubium Berland, Gayenna duplovittata Mello-Leitão, Oxysoma polytrichium Mello-Leitão, and Arachosia sulfurea Mello-Leitão. Arachosia bonneti (Mello-Leitão) is newly synonymized with A. albiventris Mello-Leitão, and A. mezenioides Mello-Leitão with A. freiburgensis Keyserling. Previous problems with the identification of species in a species complex including A. cubana (Banks) are resolved. A disjunct distributional pattern is reported for A. kapiipeoi sp. nov.; a preliminary phylogenetic analysis based on mitochondrial COI sequences shows that these may correspond with two cryptic species. In this contribution, grassland and forests are discussed as the two main habitats inhabited by species of Arachosia. Finally, we propose a hypothesis of matching sexes based on functionality of some genital structures, involving sclerites of the male copulatory organ with structures of the epigyne: the prolateral projection on the primary conductor of the male would have a direct interaction with the lateral projections of the anterior pouch on the median epigynal field of females. PMID:25781851

  12. Sublethal effect of agronomical surfactants on the spider Pardosa agrestis.

    Science.gov (United States)

    Niedobová, Jana; Hula, Vladimír; Michalko, Radek

    2016-06-01

    In addition to their active ingredients, pesticides contain also additives - surfactants. Use of surfactants has been increasing over the past decade, but their effects on non-target organisms, especially natural enemies of pests, have been studied only very rarely. The effect of three common agrochemical surfactants on the foraging behavior of the wolf spider Pardosa agrestis was studied in the laboratory. Differences in short-term, long-term, and overall cumulative predatory activities were investigated. We found that surfactant treatment significantly affected short-term predatory activity but had no effect on long-term predatory activity. The surfactants also significantly influenced the cumulative number of killed prey. We also found the sex-specific increase in cumulative kills after surfactants treatment. This is the first study showing that pesticide additives have a sublethal effect that can weaken the predatory activity of a potential biological control agent. More studies on the effects of surfactants are needed to understand how they affect beneficial organisms in agroecosystems. PMID:26878602

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

    Science.gov (United States)

    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. PMID:27312591

  14. 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.

  15. Determination of energy dissipation of a spider silk structure under impulsive loading

    Science.gov (United States)

    Alencastre, Jorge; Mago, Carlos; Rivera, Richard

    2015-09-01

    Various researches and studies have demonstrated that spider silk is much stronger and more deformable than a steel string of the same diameter from a mechanical approach. These excellent properties have caused many scientific disciplines to get involved, such as bio-mechanics, bio-materials and bio-mimetics, in order to create a material of similar properties and characteristics. It should be noted that the researches and studies have been oriented mainly as a quasi-static model. For this research, the analysis has taken a dynamic approach and determined the dissipation energy of a structure which is made of spider silk "Dragline" and produced by the Argiope-Argentata spider, through an analytical-experimental way, when being subjected to impulsive loading. Both experimental and analytical results, the latter obtained by using adjusted models, have given high levels of dissipation energy during the first cycle of vibration, which are consistent with the values suggested by other authors.

  16. Psychophysiological effects of an iTBS modulated virtual reality challenge including participants with spider phobia.

    Science.gov (United States)

    Notzon, S; Deppermann, S; Fallgatter, A; Diemer, J; Kroczek, A; Domschke, K; Zwanzger, P; Ehlis, A-C

    2015-12-01

    Preliminary evidence suggests beneficial effects of transcranial magnetic stimulation (TMS) on anxiety. The objective of this study was to investigate the effects of intermittent theta burst stimulation (iTBS) as a form of TMS on acute anxiety provoked by a virtual reality (VR) scenario. Participants with spider phobia (n=41) and healthy controls (n=42) were exposed to a spider scenario in VR after one session of iTBS over the prefrontal cortex or sham treatment. Participants with spider phobia reacted with more anxiety compared to healthy controls. Their heart rate and skin conductance increased compared to baseline. Contrary to expectations, iTBS did not influence these reactions, but modulated heart rate variability (HRV). Sympathetic influence on HRV showed an increase in the active iTBS group only. This study does not support the idea of beneficial effects of a single session of iTBS on anxiety, although other protocols or repeated sessions might be effective. PMID:26476332

  17. Design and construction of a carbon fiber gondola for the SPIDER balloon-borne telescope

    CERN Document Server

    Soler, J D; Amiri, M; Benton, S J; Bock, J J; Bond, J R; Bryan, S A; Chiang, C; Contaldi, C C; Crill, B P; Doré, O P; Farhang, M; Filippini, J P; Fissel, L M; Fraisse, A A; Gambrel, A E; Gandilo, N N; Golwala, S; Gudmundsson, J E; Halpern, M; Hasselfield, M; Hilton, G C; Holmes, W A; Hristov, V V; Irwin, K D; Jones, W C; Kermish, Z D; Kuo, C L; MacTavish, C J; Mason, P V; Megerian, K G; Moncelsi, L; Nagy, J M; Netterfield, C B; O'Brient, R; Rahlin, A S; Reintsema, C D; Ruhl, J E; Runyan, M C; Shariff, J A; Trangsrud, A; Tucker, C; Tucker, R S; Turner, A D; Weber, A C; Wiebe, D V; Young, E Y

    2014-01-01

    We introduce the light-weight carbon fiber and aluminum gondola designed for the SPIDER balloon-borne telescope. SPIDER is designed to measure the polarization of the Cosmic Microwave Background radiation with unprecedented sensitivity and control of systematics in search of the imprint of inflation: a period of exponential expansion in the early Universe. The requirements of this balloon-borne instrument put tight constrains on the mass budget of the payload. The SPIDER gondola is designed to house the experiment and guarantee its operational and structural integrity during its balloon-borne flight, while using less than 10% of the total mass of the payload. We present a construction method for the gondola based on carbon fiber reinforced polymer tubes with aluminum inserts and aluminum multi-tube joints. We describe the validation of the model through Finite Element Analysis and mechanical tests.

  18. Structural optimization of 3D-printed synthetic spider webs for high strength

    Science.gov (United States)

    Qin, Zhao; Compton, Brett G.; Lewis, Jennifer A.; Buehler, Markus J.

    2015-05-01

    Spiders spin intricate webs that serve as sophisticated prey-trapping architectures that simultaneously exhibit high strength, elasticity and graceful failure. To determine how web mechanics are controlled by their topological design and material distribution, here we create spider-web mimics composed of elastomeric filaments. Specifically, computational modelling and microscale 3D printing are combined to investigate the mechanical response of elastomeric webs under multiple loading conditions. We find the existence of an asymptotic prey size that leads to a saturated web strength. We identify pathways to design elastomeric material structures with maximum strength, low density and adaptability. We show that the loading type dictates the optimal material distribution, that is, a homogeneous distribution is better for localized loading, while stronger radial threads with weaker spiral threads is better for distributed loading. Our observations reveal that the material distribution within spider webs is dictated by the loading condition, shedding light on their observed architectural variations.

  19. Modelling spider monkeys Ateles spp. Gray, 1825: ecological responses and conservation implications to increased elevation

    Directory of Open Access Journals (Sweden)

    S. Shanee

    2009-09-01

    Full Text Available Spider monkeys (Ateles spp. are among the most widely-distributed and endangered neotropical primate genera. Throughout their distribution expanding human populations and associated demands for land are causing widespread deforestation, especially in low-lying areas where many populations of spider monkeys are being pushed to high elevation sites with sub-optimal conditions. In this paper ecological data from a wide range of sources has been collected and examined to try to better understand and predict spider monkey ecological responses to high elevation areas with lower environmental carrying capacities. Results show a significant reduction in group and foraging party sizes with increased elevation. A general reduction in density is also noted with increasing elevation, while home range sizes remain static. It is recommended that these observations be taken into account when planning conservation actions and new protected areas, and further implications are also discussed.

  20. Persistence and variation in microstructural design during the evolution of spider silk

    Science.gov (United States)

    Madurga, R.; Blackledge, T. A.; Perea, B.; Plaza, G. R.; Riekel, C.; Burghammer, M.; Elices, M.; Guinea, G.; Pérez-Rigueiro, J.

    2015-10-01

    The extraordinary mechanical performance of spider dragline silk is explained by its highly ordered microstructure and results from the sequences of its constituent proteins. This optimized microstructural organization simultaneously achieves high tensile strength and strain at breaking by taking advantage of weak molecular interactions. However, elucidating how the original design evolved over the 400 million year history of spider silk, and identifying the basic relationships between microstructural details and performance have proven difficult tasks. Here we show that the analysis of maximum supercontracted single spider silk fibers using X ray diffraction shows a complex picture of silk evolution where some key microstructural features are conserved phylogenetically while others show substantial variation even among closely related species. This new understanding helps elucidate which microstructural features need to be copied in order to produce the next generation of biomimetic silk fibers.

  1. Integrated Assessment Plan Template and Operational Demonstration for SPIDERS Phase 2: Fort Carson

    Energy Technology Data Exchange (ETDEWEB)

    Barr, Jonathan L.; Tuffner, Francis K.; Hadley, Mark D.; Kreyling, Sean J.; Schneider, Kevin P.

    2013-09-01

    This document contains the Integrated Assessment Plan (IAP) for the Phase 2 Operational Demonstration (OD) of the Smart Power Infrastructure Demonstration for Energy Reliability (SPIDERS) Joint Capability Technology Demonstration (JCTD) project. SPIDERS will be conducted over a three year period with Phase 2 being conducted at Fort Carson, Colorado. This document includes the Operational Demonstration Execution Plan (ODEP) and the Operational Assessment Execution Plan (OAEP), as approved by the Operational Manager (OM) and the Integrated Management Team (IMT). The ODEP describes the process by which the OD is conducted and the OAEP describes the process by which the data collected from the OD is processed. The execution of the OD, in accordance with the ODEP and the subsequent execution of the OAEP, will generate the necessary data for the Quick Look Report (QLR) and the Utility Assessment Report (UAR). These reports will assess the ability of the SPIDERS JCTD to meet the four critical requirements listed in the Implementation Directive (ID).

  2. Toxicity and repellency of hot pepper extracts to spider mite, Tetranychus urticae Koch.

    Science.gov (United States)

    Antonious, George F; Meyer, Janet E; Snyder, John C

    2006-01-01

    Increasing concern about persistence and environmental impact of synthetic pesticide residues require development of biodegradable and environmentally safe alternatives. The potential of using fruit extracts of hot pepper as alternatives to synthetic acaricides for controlling the two-spotted spider mite, Tetranychus urticae Koch, is explored in this study. Twenty-four Capsicum accessions (Solanaceae) were screened for their toxicity and repellency to the spider mites. Crude extracts from fruits of C. chinense, C. frutescens, C. baccatum, C. annuum, and C. pubescens were prepared in methanol and tested for their acaricidal properties. Spider mite mortality was greatest (45%) when fruit extract of accession Grif-9169 (C. annuum) was used. Results from diving board bioassays indicated that mites avoided filter paper strips treated with hot pepper extracts from accessions PI-596057 (C. baccatum), PI-195299 (C. annuum), and Grif- 9270 (C. annuum). This investigation suggests that methanolic extracts of these three accessions may have a great potential for repelling spider mites and should be field-tested on a large-scale to assess their value in managing populations of spider mites, which could reduce reliance on synthetic acaricides. An attempt was made to correlate repellency with chemical constituents of fruit extracts of the most repellent accessions to identify chemical sources of repellency. Capsaicin and dihydrocapsaicin, the pungent components of pepper fruit, were not correlated with toxicity or repellency, indicating that these are not likely related to the toxicity or repellency of the pepper fruit extracts. Other, unidentified chemicals are likely responsible for toxicity and repellency to the two-spotted spider mite. PMID:17090499

  3. Enhanced discriminative fear learning of phobia-irrelevant stimuli in spider-fearful individuals

    Directory of Open Access Journals (Sweden)

    Carina eMosig

    2014-10-01

    Full Text Available Avoidance is considered as a central hallmark of all anxiety disorders. The acquisition and expression of avoidance which leads to the maintenance and exacerbation of pathological fear is closely linked to Pavlovian and operant conditioning processes. Changes in conditionability might represent a key feature of all anxiety disorders but the exact nature of these alterations might vary across different disorders. To date, no information is available on specific changes in conditionability for disorder-irrelevant stimuli in specific phobia (SP. The first aim of this study was to investigate changes in fear acquisition and extinction in spider-fearful individuals as compared to non-fearful participants by using the de novo fear conditioning paradigm. Secondly, we aimed to determine whether differences in the magnitude of context-dependent fear retrieval exist between spider-fearful and non-fearful individuals. Our findings point to an enhanced fear discrimination in spider-fearful individuals as compared to non-fearful individuals at both the physiological and subjective level. The enhanced fear discrimination in spider-fearful individuals was neither mediated by increased state anxiety, depression, nor stress tension. Spider-fearful individuals displayed no changes in extinction learning and/or fear retrieval. Surprisingly, we found no evidence for context-dependent modulation of fear retrieval in either group. Here we provide first evidence that spider-fearful individuals show an enhanced discriminative fear learning of phobia-irrelevant (de novo stimuli. Our findings provide novel insights into the role of fear acquisition and expression for the development and maintenance of maladaptive responses in the course of SP.

  4. RFLP analysis of ribosomal DNA in sibling species of spider mite, genus Panonychus (Acari: Tetranychidae).

    Science.gov (United States)

    Osakabe, M; Sakagami, Y

    1994-02-01

    Ribosomal DNA (rDNA) restriction fragment length of spider mites was analysed in three sibling species of genus Panonychus (P. mori, P. citri and P. ulmi) and Tetranychus urticae. Seventy-one fragments were detected by enhanced chemiluminescence (ECL) after Southern hybridization with two genomic rDNA probes of mouse. Percentages of shared fragments within species were larger than those among species, indicating that the variation of rDNAs was useful in phylogenetic studies of spider mite species. In a phenogram based on differences of the rDNA fragment length, the relationship among Panonychus species was compatible with the results of analysis based on the morphological characters. PMID:7915173

  5. SpiderGL: a JavaScript 3D graphics library for next-generation WWW

    OpenAIRE

    Di Benedetto, Marco; Ponchio, Federico; Ganovelli, Fabio; Scopigno, Roberto

    2010-01-01

    Thanks to the WebGL graphics API specification for the JavaScript programming language, the possibility of using the GPU capabilities in a web browser without the need for an ad-hoc plug-in is now coming true. This paper introduces SpiderGL, a JavaScript library for developing 3D graphics web applications. SpiderGL provides data structures and algorithms to ease the use of WebGL, to define and manipulate shapes, to import 3D models in various formats, to handle asynchronous data loading. We s...

  6. Studies of the necrotic actions of the venoms of several Australian spiders.

    Science.gov (United States)

    Atkinson, R K; Wright, L G

    1991-01-01

    1. Raw venoms from a number of Australian Araneomorph spiders were found to cause epidermal disruption in cultured skin from both mice and humans. 2. The more potent ones also caused loss of epidermal cell-cell adhesion of mouse skin in vivo. 3. Raw venoms from three Mygalomorph species did not have these actions. 4. Venom gland extracts from the Araneomorph species were also ineffective. 5. It was concluded that where spider venoms appear to possess necrogenic activity the most likely reason for this is contamination of the venoms with digestive tract secretions. PMID:1676958

  7. Simulating pesticides in ditches to assess ecological risk (SPIDER): II. Benchmarking for the drainage model.

    Science.gov (United States)

    Renaud, Fabrice G; Brown, Colin D

    2008-05-01

    SPIDER (simulating pesticides in ditches to assess ecological risk) is a locally distributed, capacitance-based model that accounts for pesticide entry into surface water bodies via spray drift, surface runoff, interlayer flow and drainage. SPIDER was developed for application to small agricultural catchments. Transport of pesticide from site of application to surface water via subsurface field drains is one of the major routes of entry to surface water. Several pesticide fate models describe transfer of pesticide via drainflow, notably MACRO which has been evaluated against field data in several studies. The capacity of SPIDER to simulate drainflow and pesticide concentration in drain water was evaluated against two datasets that had been used previously to evaluate MACRO independently of this study: a plot experiment at Cockle Park and a field experiment at Maidwell, both located in the UK. In both circumstances, SPIDER was able to reproduce drain hydrographs relatively well with no or limited calibration. At Cockle Park, simulated and observed drainflow over the season were 240 and 278 mm, respectively with a Nash and Sutcliffe model efficiency (NSME) coefficient of 0.32 whilst at Maidwell they were 259 and 296 mm, respectively with a NSME coefficient of 0.55. Prediction of maximum isoproturon concentration at Cockle Park by SPIDER and MACRO were 5.3 and 13.1 microg L(- 1) respectively compared to the 3.8 microg L(- 1) measured in the field, whilst pesticide load to drains over the season were 0.22 and 1.53 g, respectively, compared to an observed load of 0.35 g. Maximum sulfosulfuron concentration at Maidwell were 2.3, 3.9 and 5.4 microg L(- 1) for observed and as simulated by SPIDER and MACRO, respectively and pesticide loading to drains of the season was 0.77, 5.61, 4.77 g, respectively. Results from the sensitivity analysis showed that the sensitivity of SPIDER compared favourably to that of several other capacity models but was more sensitive than MACRO to

  8. Numerical simulations of the first operational conditions of the negative ion test facility SPIDER

    Energy Technology Data Exchange (ETDEWEB)

    Serianni, G., E-mail: gianluigi.serianni@igi.cnr.it; Agostinetti, P.; Antoni, V.; Baltador, C.; Chitarin, G.; Marconato, N.; Pasqualotto, R.; Sartori, E.; Toigo, V.; Veltri, P. [Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, Viale dell’Università n. 2, 35020 Legnaro (Italy)

    2016-02-15

    In view of the realization of the negative ion beam injectors for ITER, a test facility, named SPIDER, is under construction in Padova (Italy) to study and optimize production and extraction of negative ions. The present paper is devoted to the analysis of the expected first operations of SPIDER in terms of single-beamlet and multiple-beamlet simulations of the hydrogen beam optics in various operational conditions. The effectiveness of the methods adopted to compensate for the magnetic deflection of the particles is also assessed. Indications for a sequence of the experimental activities are obtained.

  9. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io;

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies in the...

  10. Noncommutative black holes

    International Nuclear Information System (INIS)

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole

  11. Black Entrepreneurship in America.

    Science.gov (United States)

    Green, Shelley; Pryde, Paul

    The economic condition of black Americans is discussed, proceeding from the assumption that black economic progress does not depend on a renewed struggle for unobtained civil rights, but rather on the creative response of black Americans to economic opportunity and problems. In the long run, black economic development must rely on the…

  12. [Intramolecular homologous recombination event occurred in the spider egg case silk gene CySp2 of wasp spider].

    Science.gov (United States)

    Han, L; Nakagaki, M

    2013-01-01

    To gain further understanding of egg case silk proteins gene family, Zhao et al. isolated two full-length cDNAs for egg case silk proteins, cylindrical silk protein 1 (CySpl) and cylindrical silk protein 2 (CySp2), from the wasp spider, Argiope bruennichi. CySp2 was reported to contain no apparent signal peptide sequences, and the CySp1-CySp2 complex, which would possess a signal peptide, would be transported across the endoplasmic reticulum and secreted to the Golgi. Genomic DNA sequencing is one approach that can be successfully utilized to retrieve 5' ends of silk genes; using this method, we retrieved the 5' end of CySp2. We found that CySp2 contained a typical signal peptide similar to that found in CySp1; thus, due to technical limitations, an artificial error had occurred in the CySp2 sequence reported by Zhao et al. PMID:25509350

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

    Science.gov (United States)

    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. PMID:22251680

  14. Bird-spiders (Arachnida, Mygalomorphae as perceived by the inhabitants of the village of Pedra Branca, Bahia State, Brazil

    Directory of Open Access Journals (Sweden)

    Neto Eraldo

    2006-11-01

    Full Text Available Abstract This paper deals with the conceptions, knowledge and attitudes of the inhabitants of the county of Pedra Branca, Bahia State, on mygalomorph spiders locally known as 'caranguejeiras' (bird-spiders. It is launched here a new filed within ethnozoology: ethnoarachnology, which is defined as the transdisciplinary study of the relationships between human beings and bird-spiders. Data were collected from February to June 2005 by means of open-ended interviews carried out with 30 individuals, which ages ranged from 13 to 86 years old. It was recorded some traditional knowledge regarding the following items: taxonomy, biology, habitat, ecology, seasonality, and behavior. Results show that bird-spiders are classified as "insects". The most commented aspect of the interaction between bird-spiders and inhabitants of Pedra Branca is related to their dangerousness, since they said these spiders are very venomous and can cause health problems. In general, the traditional zoological knowledge of Pedra Branca's inhabitants concerning these spiders is coherent with the academic knowledge.

  15. 华北抗日根据地丧偶妇女再嫁问题研究%Remarriage Problems of Widowed Women in North China Anti-Japanese Base Areas

    Institute of Scientific and Technical Information of China (English)

    郑立柱; 郑皓予

    2016-01-01

    Before the establishment of North China Anti Japanese base areas, the widowed women ’s rights for remarriage were not supported by public opinion and relevant rights couldn’t be guaranteed as well. Right after the establishment of North China Anti Japanese base areas, the Communist Party formulated and improved relevant laws, to carried out propaganda, to come to the aid of widowed women, to punish violations of widowed women remarriage rights, safeguard widowed women's rights and interests, improve the status of the remarried women. The Communist Party of China’s efforts had achieved some positive results, but due to the influence of traditional idea and social habits, there were still many unsatisfactory parts for the remarried widowed women and protection of women ’s rights had a long way to go.%华北抗日根据地开辟前,丧偶妇女再嫁得不到社会舆论的支持,相关权益也得不到保障。华北抗日根据地开辟后,中国共产党政权通过制定和完善相关法令、开展舆论宣传、援助丧偶妇女再嫁行为、惩处侵犯丧偶妇女再婚权益者等路径,保障丧偶妇女相关权益,改善丧偶妇女再婚状况。中国共产党的努力,取得了一定的成效,但由于传统观念和社会习惯的影响,丧偶妇女再嫁还存在很多不尽如人意的地方,保障妇女权益任重而道远。

  16. Molecular identification of adult and juvenile linyphiid and theridiid spiders in Alpine glacier foreland communities.

    Directory of Open Access Journals (Sweden)

    Lorna Raso

    Full Text Available 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.

  17. A 4-year study of invasive and native spider populations in Maine

    Science.gov (United States)

    Jakob, Elizabeth M.; Porter, Adam H.; Ginsberg, Howard; Bednarski, Julie V.; Houser, Jeremy

    2011-01-01

    Invasive spiders pose potential threats to native spiders. In 2002, the European spider Linyphia triangularis (Clerck, 1757) (Araneae: Linyphiidae) was discovered in all but one county in Maine. At Acadia National Park, we conducted a 4-year study of L. triangularis and three native linyphiid species of a similar size (Frontinella communis (Hentz, 1850), Pityohyphantes subarcticus Chamberlin and Ivie, 1943, and Neriene radiata (Walckenaer, 1842)). Using line-transect surveys, we measured population densities in coastal and forest habitat. The density of L. triangularis varied across years but was always significantly higher on the coast than in the forest. In contrast, only one native species was present on the coast and at very low numbers. Coastal L. triangularis were larger and in better condition than those in the forest, and numbers and biomass of insect prey were also higher on the coast. In 2 years, we also conducted transects at a second coastal location in Maine where the invader was at low density. At that site, native densities were substantially higher than at either Acadia site. Our data are consistent with the hypothesis that L. triangularis is reducing populations of native spiders. Companion studies suggest that L. triangularis negatively impacts natives by usurping both web sites and webs.

  18. Geri Keams: "Coyote and Spider Woman and Other Creation Stories." Cue Sheet.

    Science.gov (United States)

    Carr, Gail

    This performance guide is designed for teachers to use with students before and after a storytelling performance of "Coyote and Spider Woman and Other Creation Stories," by Geri Keams, a Navajo storyteller. The guide, called a "Cuesheet," contains seven activity sheets for use in class, addressing: (1) The Storyteller Tells Her Story (where the…

  19. Can quarries supplement rare xeric habitats in a piedmont region? Comparison of spiders and ground beetles

    Czech Academy of Sciences Publication Activity Database

    Tropek, R.; Spitzer, L.; Konvička, Martin

    Birmensdorf : Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 2007 - (Feldmeyer-Christe, E.). s. 44-44 [Monitoring the Effectiveness of Nature Conservation. 03.09.2007-06.09.2007, Birmensdorf] Institutional research plan: CEZ:AV0Z50070508 Keywords : anthropogenous sites * spiders * carabids Subject RIV: EH - Ecology, Behaviour

  20. Spiders on sandstone rocks in Central Europe with particular reference to the Bohemian Switzerland National Park

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil

    Praha : Academia, 2007 - (Hartel, H.; Cílek, V.; Herben, T.; Jackson, A.; Williams, R.), s. 143-147 ISBN 978-80-200-1577-8 Institutional research plan: CEZ:AV0Z50070508 Keywords : spiders * Araneae * sandstone Subject RIV: EG - Zoology

  1. Side effects of kaolin particle films on apple orchard bug, beetle and spider communities

    NARCIS (Netherlands)

    Marko, V.; Bogya, S.; Kondorosy, E.; Blommers, L.H.M.

    2010-01-01

    The effects of multiple applications of hydrophobic kaolin particle film on apple orchard bug (Heteroptera), beetle (Coleoptera) and spider (Araneae) assemblages were studied in the Netherlands. Insecticide-free orchard plots served as a control. The kaolin applications significantly reduced the abu

  2. Reproducing Natural Spider Silks' Copolymer Behavior in Synthetic Silk Mimics

    Energy Technology Data Exchange (ETDEWEB)

    An, Bo; Jenkins, Janelle E; Sampath, Sujatha; Holland, Gregory P; Hinman, Mike; Yarger, Jeffery L; Lewis, Randolph [Wyoming; (Sandia); (Utah SU); (AZU)

    2012-10-30

    Dragline silk from orb-weaving spiders is a copolymer of two large proteins, major ampullate spidroin 1 (MaSp1) and 2 (MaSp2). The ratio of these proteins is known to have a large variation across different species of orb-weaving spiders. NMR results from gland material of two different species of spiders, N. clavipes and A. aurantia, indicates that MaSp1 proteins are more easily formed into β-sheet nanostructures, while MaSp2 proteins form random coil and helical structures. To test if this behavior of natural silk proteins could be reproduced by recombinantly produced spider silk mimic protein, recombinant MaSp1/MaSp2 mixed fibers as well as chimeric silk fibers from MaSp1 and MaSp2 sequences in a single protein were produced based on the variable ratio and conserved motifs of MaSp1 and MaSp2 in native silk fiber. Mechanical properties, solid-state NMR, and XRD results of tested synthetic fibers indicate the differing roles of MaSp1 and MaSp2 in the fiber and verify the importance of postspin stretching treatment in helping the fiber to form the proper spatial structure.

  3. 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.

  4. Coercive copopulation in two sexually cannibalistic camel-spider species (Arachnida: Solifugae)

    DEFF Research Database (Denmark)

    Hrusková-Martisová, M.; Pekár, S.; Bilde, T.

    2010-01-01

    Males can overcome female resistance to mating either by using luring behaviour or through sexual coercion. We studied mating behaviour in two sexually cannibalistic camel-spider species Galeodes caspius subfuscus (Galeodidae) and Gluvia dorsalis (Desiidae), to determine the presence of luring an......-predation strategy, as sexual cannibalism occurred in c. 40% of all sexual interactions....

  5. Drivers of diversity in Macaronesian spiders and the role of species extinctions

    OpenAIRE

    Cardoso, Pedro; Arnedo, Miquel A.; Triantis, Kostas A.; Borges, Paulo A. V.

    2010-01-01

    Copyright © 2010 Blackwell Publishing. AIM To identify the biogeographical factors underlying spider species richness in the Macaronesian region and assess the importance of species extinctions in shaping the current diversity. LOCATION The European archipelagos of Macaronesia with an emphasis on the Azores and Canary Islands.

  6. Exposure Therapy for Fear of Spiders in an Adult with Learning Disabilities: A Case Report

    Science.gov (United States)

    Cowdrey, Felicity A.; Walz, Linda

    2015-01-01

    The evidence-base for exposure therapy in people with learning disabilities experiencing specific phobias is sparse. This case study describes the assessment, formulation and treatment of spider phobia in a woman with learning disabilities using an exposure-based intervention augmented with mindfulness practice and bereavement work. To evaluate…

  7. Insects as biological models to assay spider and scorpion venom toxicity

    OpenAIRE

    M. F. Manzoli-Palma; N. GOBBI; Palma, M. S.

    2003-01-01

    This study was undertaken to develop an experimental protocol using insects as biological models to assay venom toxicity of the following spiders Loxosceles gaucho, Phoneutria nigriventer, Nephilengys cruentata and Tityus serrulatus scorpion. Three different insect species were bioassayed: Apis mellifera (Hymenoptera), Grillus assimilis (Orthoptera), and Diatraea saccharalis (Lepidoptera). Venoms were injected into the hemocele of insects with a microsyringe at concentrations that caused dose...

  8. Orb-weaving spider diversity in the Iberá Marshlands, Argentina.

    Science.gov (United States)

    Rubio, Gonzalo D; Moreno, Claudia E

    2010-01-01

    The Iberá Marshlands RAMSAR reserve, in the northeast of Argentina, is one of the largest and most important wetlands of America. In this study we assess orb-weaving spider (Araneae: Orbiculariae) diversity in this reserve, analyzing different facets of local diversity (species richness, diversity, evenness and taxonomic distinctness), and the contribution of species differentiation (beta diversity) among localities and habitat types to the composition of regional diversity. We found 1657 individuals of 59 orb-weaving spider species/morphospecies. Local diversity differs among the three sampled localities. At the habitat level, the different facets of biodiversity followed a clear pattern, where woodlands have higher species richness, diversity, evenness and taxonomic distinctness than savannas. Savanna sites shared a common spider species composition, while woodland communities have high values of complementarity. Thus, beta diversity has a very high contribution to the regional diversity of the orb-weaving spiders in the Iberá Marshlands. We suggest that conservation management in the reserve should be directed towards promoting natural spatial heterogeneity, giving special protection to habitat mosaics in different localities. PMID:20877983

  9. Blood-injection-injury phobia and fear of spiders : Domain specific individual differences in disgust sensitivity

    NARCIS (Netherlands)

    Merckelbach, H; de Jong, Peter

    1998-01-01

    We investigated whether disgust sensitivity is associated with blood-injection-injury (BII) and spider fear. We also explored whether the relationship between disgust sensitivity and phobic fears is domain specific. Ninety-six undergraduates (all women) completed the Disgust Questionnaire (DQ) (Rozi

  10. Fecal and Salivary Cortisol Concentrations in Woolly (Lagothrix ssp.) and Spider Monkeys (Ateles spp.)

    NARCIS (Netherlands)

    Ange-van Heugten, K.D.; Heugten, van E.; Timmer, S.; Bosch, G.; Elias, A.; Whisnant, S.; Swarts, H.J.M.; Ferket, P.; Verstegen, M.W.A.

    2009-01-01

    Detrimental physiological effects due to stressors can contribute to the low captive success of primates. The objective of this research was to investigate the potential impact of diet composition on cortisol concentrations in feces and saliva in woolly (n=27) and spider monkeys (n=61). The research

  11. 3D Finite Element Analysis of Spider Non-isothermal Forging Process

    Science.gov (United States)

    Niu, Ling; Wei, Wei; Wei, Kun Xia; Alexandrov, Igor V.; Hu, Jing

    2016-06-01

    The differences of effective stress, effective strain, velocity field, and the load-time curves between the spider isothermal and non-isothermal forging processes are investigated by making full use of 3D FEA, and verified by the production experiment of spider forging. Effective stress is mainly concentrated on the pin, and becomes lower closer to the front of the pin. The maximum effective strain in the non-isothermal forging is lower than that in the isothermal. The great majority of strain in the non-isothermal forging process is 1.76, which is larger than the strain of 1.31 in the isothermal forging. The maximum load required in the isothermal forging is higher than that in the non-isothermal. The maximum experimental load and deformation temperature in the spider production are in good agreement with those in the non-isothermal FEA. The results indicate that the non-isothermal 3D FEA results can guide the design of the spider forging process.

  12. Turkish adaptation of the Fear of Spiders Questionnaire: Reliability and validity in non-clinical samples

    Directory of Open Access Journals (Sweden)

    Robert W. Booth

    2016-12-01

    Full Text Available The rapid, objective measurement of spider fear is important for clinicians, and for researchers studying fear. To facilitate this, we adapted the Fear of Spiders Questionnaire (FSQ into Turkish. The FSQ is quick to complete and easy to understand. Compared to the commonly used Spider Phobia Questionnaire, it has shown superior test-retest reliability and better discrimination of lower levels of spider fear, facilitating fear research in non-clinical samples. In two studies, with 137 and 105 undergraduates and unselected volunteers, our adapted FSQ showed excellent internal consistency (Cronbach’s α = .95 and .96 and test-retest reliability (r = .90, and good discriminant validity against the State–Trait Anxiety Inventory—Trait (r = .23 and Beck Anxiety Inventory—Trait (r = .07. Most importantly, our adapted FSQ significantly predicted 26 students’ self-reported discomfort upon approaching a caged tarantula; however, a measure of behavioural avoidance of the tarantula yielded little variability, so a more sensitive task will be required for future behavioural testing. Based on this initial testing, we recommend our adapted FSQ for research use. Further research is required to verify that our adapted FSQ discriminates individuals with and without phobia effectively. A Turkish-language report of the studies is included as supplementary material.

  13. Quantitative analysis of spider locomotion employing computer-automated video tracking

    DEFF Research Database (Denmark)

    Baatrup, E; Bayley, M

    1993-01-01

    The locomotor activity of adult specimens of the wolf spider Pardosa amentata was measured in an open-field setup, using computer-automated colour object video tracking. The x,y coordinates of the animal in the digitized image of the test arena were recorded three times per second during four...

  14. Extant primitively segmented spiders have recently diversified from an ancient lineage

    Science.gov (United States)

    Xu, Xin; Liu, Fengxiang; Cheng, Ren-Chung; Chen, Jian; Xu, Xiang; Zhang, Zhisheng; Ono, Hirotsugu; Pham, Dinh Sac; Norma-Rashid, Y.; Arnedo, Miquel A.; Kuntner, Matjaž; Li, Daiqin

    2015-01-01

    Living fossils are lineages that have retained plesiomorphic traits through long time periods. It is expected that such lineages have both originated and diversified long ago. Such expectations have recently been challenged in some textbook examples of living fossils, notably in extant cycads and coelacanths. Using a phylogenetic approach, we tested the patterns of the origin and diversification of liphistiid spiders, a clade of spiders considered to be living fossils due to their retention of arachnid plesiomorphies and their exclusive grouping in Mesothelae, an ancient clade sister to all modern spiders. Facilitated by original sampling throughout their Asian range, we here provide the phylogenetic framework necessary for reconstructing liphistiid biogeographic history. All phylogenetic analyses support the monophyly of Liphistiidae and of eight genera. As the fossil evidence supports a Carboniferous Euramerican origin of Mesothelae, our dating analyses postulate a long eastward over-land dispersal towards the Asian origin of Liphistiidae during the Palaeogene (39–58 Ma). Contrary to expectations, diversification within extant liphistiid genera is relatively recent, in the Neogene and Late Palaeogene (4–24 Ma). While no over-water dispersal events are needed to explain their evolutionary history, the history of liphistiid spiders has the potential to play prominently in vicariant biogeographic studies. PMID:25948684

  15. Spider-silk-like shape memory polymer fiber for vibration damping

    International Nuclear Information System (INIS)

    In this study, the static and dynamic properties of shape memory polyurethane (SMPU) fiber are reported and compared to those of spider dragline silk. Although the polymeric fiber has a lower strength compared to spider dragline silks (0.2–0.3 GPa versus 1.1 GPa), it possesses much higher toughness (276–289 MJ m−3 versus 160 MJ m−3), due to its excellent extensibility. The dynamic mechanical tests reveal that SMPU fiber has a high damping capacity (tan δ = 0.10–0.35) which is comparable to or even higher than that of spider silks (tan δ = 0.15). In addition, we found that, different programming methods change the shape memory and damping properties of the fiber in different ways and cold-drawing programming is more advocated in structural applications. These results suggest that the SMPU fiber has similar vibration damping and mechanical properties as spider silk, and may find applications in lightweight engineering structures. (paper)

  16. [Research Progress in Black Queen Cell Virus Causing Disease].

    Science.gov (United States)

    Yang, Qian; Zhang, Jian; Song, Zhanyun; Zheng, Yan; Wang, Xianghui; Sui, Jiachen; Wang, Zhenguo; Mou, Jun

    2015-05-01

    In nature, honeybees are the most important pollinators. They play a vital role in both protecting the diversity of natural ecosystems, and maintaining the yield-improving effects of agroecosystems. But in recent years, epidemic disease in bees has caused huge losses. Black Queen Cell Virus (BQCV) is a bee pathogen that was first reported in 1955. It mainly infects bee larvae and pupae, making their bodies turn dark and black, and causing a massive decrease in the bee population. More specifically, the virus makes the exterior of the cell walls in the larvae and pupae turn black. BQCV is a seasonal epidemic, spread by means horizontal and vertical transmission, and is often unapparent. BQCV not only infects a variety of bee species, but also spiders, centipedes and other arthropods. It can also be coinfected with other honeybee viruses. In recent years, research has shown that the Nosema intestinal parasite plays an important role in BQCV transmission and bees carrying Nosema that become infected with BQCV have increased mortality. Here we summarize current research on the incidence, prevalence, geographical distribution and transmission of BQCV. PMID:26470541

  17. Bioprospecting finds the toughest biological material: extraordinary silk from a giant riverine orb spider.

    Directory of Open Access Journals (Sweden)

    Ingi Agnarsson

    Full Text Available BACKGROUND: Combining high strength and elasticity, spider silks are exceptionally tough, i.e., able to absorb massive kinetic energy before breaking. Spider silk is therefore a model polymer for development of high performance biomimetic fibers. There are over 41,000 described species of spiders, most spinning multiple types of silk. Thus we have available some 200,000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila or simply from researchers' backyards. Are we limited to 'blindly fishing' in efforts to discover extraordinary silks? Or, could scientists use ecology to predict which species are likely to spin silks exhibiting exceptional performance properties? METHODOLOGY: We examined the biomechanical properties of silk produced by the remarkable Malagasy 'Darwin's bark spider' (Caerostris darwini, which we predicted would produce exceptional silk based upon its amazing web. The spider constructs its giant orb web (up to 2.8 m(2 suspended above streams, rivers, and lakes. It attaches the web to substrates on each riverbank by anchor threads as long as 25 meters. Dragline silk from both Caerostris webs and forcibly pulled silk, exhibits an extraordinary combination of high tensile strength and elasticity previously unknown for spider silk. The toughness of forcibly silked fibers averages 350 MJ/m(3, with some samples reaching 520 MJ/m(3. Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®. Caerostris capture spiral silk is similarly exceptionally tough. CONCLUSIONS: Caerostris darwini produces the toughest known biomaterial. We hypothesize that this extraordinary toughness coevolved with the unusual ecology and web architecture of these spiders, decreasing the likelihood of bridgelines breaking and collapsing the web

  18. Research on Focused Spider%主题爬虫研究进展

    Institute of Scientific and Technical Information of China (English)

    王贤明

    2014-01-01

    With the rapid development of the Internet technology, the amount of pages in the WWW has grown dramatically and search engines are irreplaceable for web users and become the entries of the web for people. Web spider, as the data source for search engine, is the most important component of search engine. Introduces the key technologies of web spider. In addition, the growing individual needs of web users as well as the dramatic increase in the number of pages leading general search engines can not meet the specific needs of users. The topic-based search engines have been rapid development. The focused spider has also been great breakthroughs and progress in the meanwhile. Unlike general spiders, general spiders focused crawling general integrity, and the focused spiders emphasize the relevance of a particular topic. Introduces the researches on focused spiders.%随着互联网技术的飞速发展,网页数量急剧增加,搜索引擎的地位已经不可取代,成为人们使用Internet的入口。网络蜘蛛作为搜索引擎的信息来源是搜索引擎必不可少的组成部分。介绍网络蜘蛛设计中的关键技术。另外,随着用户个性化需求越来越强以及网页数量的急剧增加导致通用搜索引擎无法满足特定用户的需求,专业搜索引擎得到快速的发展。同时对于主题爬虫的研究也有很大的突破和进展。主题爬虫有别于通用爬虫,通用爬虫注重爬取的完整性,而主题爬虫强调网页与特定主题的相关性。同时对主题爬虫的研究现状进行介绍和总结。

  19. SignalSpider: Probabilistic pattern discovery on multiple normalized ChIP-Seq signal profiles

    KAUST Repository

    Wong, Kachun

    2014-09-05

    Motivation: Chromatin immunoprecipitation (ChIP) followed by high-throughput sequencing (ChIP-Seq) measures the genome-wide occupancy of transcription factors in vivo. Different combinations of DNA-binding protein occupancies may result in a gene being expressed in different tissues or at different developmental stages. To fully understand the functions of genes, it is essential to develop probabilistic models on multiple ChIP-Seq profiles to decipher the combinatorial regulatory mechanisms by multiple transcription factors. Results: In this work, we describe a probabilistic model (SignalSpider) to decipher the combinatorial binding events of multiple transcription factors. Comparing with similar existing methods, we found SignalSpider performs better in clustering promoter and enhancer regions. Notably, SignalSpider can learn higher-order combinatorial patterns from multiple ChIP-Seq profiles. We have applied SignalSpider on the normalized ChIP-Seq profiles from the ENCODE consortium and learned model instances. We observed different higher-order enrichment and depletion patterns across sets of proteins. Those clustering patterns are supported by Gene Ontology (GO) enrichment, evolutionary conservation and chromatin interaction enrichment, offering biological insights for further focused studies. We also proposed a specific enrichment map visualization method to reveal the genome-wide transcription factor combinatorial patterns from the models built, which extend our existing fine-scale knowledge on gene regulation to a genome-wide level. Availability and implementation: The matrix-algebra-optimized executables and source codes are available at the authors\\' websites: http://www.cs.toronto.edu/∼wkc/SignalSpider. Contact: Supplementary information: Supplementary data are available at Bioinformatics online.

  20. Thermal conditions during juvenile development affect adult dispersal in a spider.

    Science.gov (United States)

    Bonte, Dries; Travis, Justin M J; De Clercq, Nele; Zwertvaegher, Ingrid; Lens, Luc

    2008-11-01

    Understanding the causes and consequences of dispersal is a prerequisite for the effective management of natural populations. Rather than treating dispersal as a fixed trait, it should be considered a plastic process that responds to both genetic and environmental conditions. Here, we consider how the ambient temperature experienced by juvenile Erigone atra, a spider inhabiting crop habitat, influences adult dispersal. This species exhibits 2 distinct forms of dispersal, ballooning (long distance) and rappelling (short distance). Using a half-sib design we raised individuals under 4 different temperature regimes and quantified the spiders' propensity to balloon and to rappel. Additionally, as an indicator of investment in settlement, we determined the size of the webs build by the spiders following dispersal. The optimal temperature regimes for reproduction and overall dispersal investment were 20 degrees C and 25 degrees C. Propensity to perform short-distance movements was lowest at 15 degrees C, whereas for long-distance dispersal it was lowest at 30 degrees C. Plasticity in dispersal was in the direction predicted on the basis of the risks associated with seasonal changes in habitat availability; long-distance ballooning occurred more frequently under cooler, spring-like conditions and short-distance rappelling under warmer, summer-like conditions. Based on these findings, we conclude that thermal conditions during development provide juvenile spiders with information about the environmental conditions they are likely to encounter as adults and that this information influences the spider's dispersal strategy. Climate change may result in suboptimal adult dispersal behavior, with potentially deleterious population level consequences. PMID:18974219

  1. Interactive effects of fire and large herbivores on web-building spiders.

    Science.gov (United States)

    Foster, C N; Barton, P S; Wood, J T; Lindenmayer, D B

    2015-09-01

    Altered disturbance regimes are a major driver of biodiversity loss worldwide. Maintaining or re-creating natural disturbance regimes is therefore the focus of many conservation programmes. A key challenge, however, is to understand how co-occurring disturbances interact to affect biodiversity. We experimentally tested for the interactive effects of prescribed fire and large macropod herbivores on the web-building spider assemblage of a eucalypt forest understorey and investigated the role of vegetation in mediating these effects using path analysis. Fire had strong negative effects on the density of web-building spiders, which were partly mediated by effects on vegetation structure, while negative effects of large herbivores on web density were not related to changes in vegetation. Fire amplified the effects of large herbivores on spiders, both via vegetation-mediated pathways and by increasing herbivore activity. The importance of vegetation-mediated pathways and fire-herbivore interactions differed for web density and richness and also differed between web types. Our results demonstrate that for some groups of web-building spiders, the effects of co-occurring disturbance drivers may be mostly additive, whereas for other groups, interactions between drivers can amplify disturbance effects. In our study system, the use of prescribed fire in the presence of high densities of herbivores could lead to reduced densities and altered composition of web-building spiders, with potential cascading effects through the arthropod food web. Our study highlights the importance of considering both the independent and interactive effects of disturbances, as well as the mechanisms driving their effects, in the management of disturbance regimes. PMID:25935217

  2. Heterologous expression of five disulfide-bonded insecticidal spider peptides.

    Science.gov (United States)

    Estrada, Georgina; Silva, Anita O; Villegas, Elba; Ortiz, Ernesto; Beirão, Paulo S L; Corzo, Gerardo

    2016-09-01

    The genes of the five disulfide-bonded peptide toxins 1 and 2 (named Oxytoxins or Oxotoxins) from the spider Oxyopes lineatus were cloned into the expression vector pQE30 containing a 6His-tag and a Factor Xa proteolytic cleavage region. These two recombinant vectors were transfected into Escherichia coli BL21 cells and expressed under induction with isopropyl thiogalactoside (IPTG). The product of each gene was named HisrOxyTx1 or HisrOxyTx2, and the protein expression was ca 14 and 6 mg/L of culture medium, respectively. Either recombinant toxin HisrOxyTx1 or HisrOxyTx2 were found exclusively in inclusion bodies, which were solubilized using a chaotropic agent, and then, purified using affinity chromatography and reverse-phase HPLC (RP-HPLC). The HisrOxyTx1 and HisrOxyTx2 products, obtained from the affinity chromatographic step, showed several peptide fractions having the same molecular mass of 9913.1 and 8030.1 Da, respectively, indicating that both HisrOxyTx1 and HisrOxyTx2 were oxidized forming several distinct disulfide bridge arrangements. The isoforms of both HisrOxyTx1 and HisrOxyTx2 after DTT reduction eluted from the column as a single protein component of 9923 and 8040 Da, respectively. In vitro folding of either HisrOxyTx1 or HisrOxyTx2 yielded single oxidized components, which were cleaved independently by the proteolytic enzyme Factor Xa to give the recombinant peptides rOxyTx1 and rOxyTx2. The experimental molecular masses of rOxyTx1 and rOxyTx2 were 8059.0 and 6176.4 Da, respectively, which agree with their expected theoretical masses. The recombinant peptides rOxyTx1 and rOxyTx2 showed lower but comparable toxicity to the native toxins when injected into lepidopteran larvae; furthermore, rOxyTx1 was able to inhibit calcium ion currents on dorsal unpaired median (DUM) neurons from Periplaneta americana. PMID:27263806

  3. 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.

  4. Final critical habitat for the Kauai cave wolf spider (Adelocosa anops) and the Kauai cave amphipod (Spelaeorchestia koloana)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify, in general, the areas where final critical habitat for the Kauai cave wolf spider (Adelocosa anops) and the Kauai cave amphipod...

  5. Final Critical Habitat for Kauai cave wolf spider (Adelocosa anops) and the Kauai cave amphipod (Spelaeorchestia koloana).

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify, in general, the areas of final critical habitat for Kauai cave wolf spider (Adelocosa anops) and the Kauai cave amphipod (Spelaeorchestia...

  6. The Black Studies Boondoggle

    Science.gov (United States)

    Long, Richard A.

    1970-01-01

    Indicates tendencies dangerous to the basic purpose of Black Studies, and identifies four external challeges--imperialism, paternalism, nihilism, and materialism. An internal challenge is considered to be the use of European and Establishment constructs to analyze black reality. (DM)

  7. Dynamics of black holes

    OpenAIRE

    Hayward, Sean A.

    2008-01-01

    This is a review of current theory of black-hole dynamics, concentrating on the framework in terms of trapping horizons. Summaries are given of the history, the classical theory of black holes, the defining ideas of dynamical black holes, the basic laws, conservation laws for energy and angular momentum, other physical quantities and the limit of local equilibrium. Some new material concerns how processes such as black-hole evaporation and coalescence might be described by a single trapping h...

  8. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

    2007-11-15

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

  9. Black Hole Statistics

    OpenAIRE

    Strominger, Andrew

    1993-01-01

    The quantum statistics of charged, extremal black holes is investigated beginning with the hypothesis that the quantum state is a functional on the space of closed three-geometries, with each black hole connected to an oppositely charged black hole through a spatial wormhole. From this starting point a simple argument is given that a collection of extremal black holes obeys neither Bose nor Fermi statistics. Rather they obey an exotic variety of particle statistics known as ``infinite statist...

  10. Phantom Black Holes

    OpenAIRE

    Gao, C. J.; Zhang, S. N.

    2006-01-01

    The exact solutions of electrically charged phantom black holes with the cosmological constant are constructed. They are labelled by the mass, the electrical charge, the cosmological constant and the coupling constant between the phantom and the Maxwell field. It is found that the phantom has important consequences on the properties of black holes. In particular, the extremal charged phantom black holes can never be achieved and so the third law of thermodynamics for black holes still holds. ...

  11. Spiders associated with Psychotria carthagenensis Jacquin. (Rubiaceae): vegetative branches versus inflorescences, and the influence of Crematogaster sp. (Hymenoptera, Formicidae), in South-Pantanal, Brazil.

    Science.gov (United States)

    Faria, R R; Lima, T N

    2008-05-01

    The aim of this study was to analyze: i) the spider community in vegetative and reproductive branches of Psychotria carthagenensis concerning relative abundance, guild composition and body size distribution; ii) ant abundance in different types of branches and iii) the spider behavior when experimentally put in contact with inflorescences covered with ants. There was no difference between vegetative and reproductive branches in relation to spider abundance, composition of guilds and body size distribution of spiders. However, there was a significant difference in ant abundance. In the behavioral experiment, 90% of the spiders were expelled from inflorescences by ants; in control treatment, 100% remained in the inflorescences. The ant density in different parts of the plant may explain the spider distribution. PMID:18660949

  12. Brain dynamics of visual attention during anticipation and encoding of threat- and safe-cues in spider-phobic individuals.

    Science.gov (United States)

    Michalowski, Jaroslaw M; Pané-Farré, Christiane A; Löw, Andreas; Hamm, Alfons O

    2015-09-01

    This study systematically investigated the sensitivity of the phobic attention system by measuring event-related potentials (ERPs) in spider-phobic and non-phobic volunteers in a context where spider and neutral pictures were presented (phobic threat condition) and in contexts where no phobic but unpleasant and neutral or only neutral pictures were displayed (phobia-irrelevant conditions). In a between-group study, participants were assigned to phobia-irrelevant conditions either before or after the exposure to spider pictures (pre-exposure vs post-exposure participants). Additionally, each picture was preceded by a fixation cross presented in one of three different colors that were informative about the category of an upcoming picture. In the phobic threat condition, spider-phobic participants showed a larger P1 than controls for all pictures and signal cues. Moreover, individuals with spider phobia who were sensitized by the exposure to phobic stimuli (i.e. post-exposure participants) responded with an increased P1 also in phobia-irrelevant conditions. In contrast, no group differences between spider-phobic and non-phobic individuals were observed in the P1-amplitudes during viewing of phobia-irrelevant stimuli in the pre-exposure group. In addition, cues signaling neutral pictures elicited decreased stimulus-preceding negativity (SPN) compared with cues signaling emotional pictures. Moreover, emotional pictures and cues signaling emotional pictures evoked larger early posterior negativity (EPN) and late positive potential (LPP) than neutral stimuli. Spider phobics showed greater selective attention effects than controls for phobia-relevant pictures (increased EPN and LPP) and cues (increased LPP and SPN). Increased sensitization of the attention system observed in spider-phobic individuals might facilitate fear conditioning and promote generalization of fear playing an important role in the maintenance of anxiety disorders. PMID:25608985

  13. Effects of different post-spin stretching conditions on the mechanical properties of synthetic spider silk fibers

    OpenAIRE

    Albertson, Amy E.; Teulé, Florence; Weber, Warner; Yarger, Jeffery L.; Lewis, Randolph V.

    2013-01-01

    Spider silk is a biomaterial with impressive mechanical properties, resulting in various potential applications. Recent research has focused on producing synthetic spider silk fibers with the same mechanical properties as the native fibers. For this study, three proteins based on the Argiope aurantia Major ampullate Spidroin 2 consensus repeat sequence were expressed, purified and spun into fibers. A number of post-spin draw conditions were tested to determine the effect of each condition on ...

  14. Warring arthropod societies: Social spider colonies can delay annihilation by predatory ants via reduced apparency and increased group size.

    Science.gov (United States)

    Keiser, Carl N; Wright, Colin M; Pruitt, Jonathan N

    2015-10-01

    Sociality provides individuals with benefits via collective foraging and anti-predator defense. One of the costs of living in large groups, however, is increased apparency to natural enemies. Here, we test how the individual-level and collective traits of spider societies can increase the risk of discovery and death by predatory ants. We transplanted colonies of the social spider Stegodyphus dumicola into a habitat dense with one of their top predators, the pugnacious ant Anoplolepis custodiens. With three different experiments, we test how colony-wide survivorship in a predator-dense habitat can be altered by colony apparency (i.e., the presence of a capture web), group size, and group composition (i.e., the proportion of bold and shy personality types present). We also test how spiders' social context (i.e., living solitarily vs. among conspecifics) modifies their behaviour toward ants in their capture web. Colonies with capture webs intact were discovered by predatory ants on average 25% faster than colonies with the capture web removed, and all discovered colonies eventually collapsed and succumbed to predation. However, the lag time from discovery by ants to colony collapse was greater for colonies containing more individuals. The composition of individual personality types in the group had no influence on survivorship. Spiders in a social group were more likely to approach ants caught in their web than were isolated spiders. Isolated spiders were more likely to attack a safe prey item (a moth) than they were to attack ants and were more likely to retreat from ants after contact than they were after contact with moths. Together, our data suggest that the physical structures produced by large animal societies can increase their apparency to natural enemies, though larger groups can facilitate a longer lag time between discovery and demise. Lastly, the interaction between spiders and predatory ants seems to depend on the social context in which spiders reside

  15. Old maids have more appeal: effects of age and pheromone source on mate attraction in an orb-web spider

    OpenAIRE

    Cory, Anna-Lena; Schneider, Jutta M

    2016-01-01

    Background. In many insects and spider species, females attract males with volatile sex pheromones, but we know surprisingly little about the costs and benefits of female pheromone emission. Here, we test the hypothesis that mate attraction by females is dynamic and strategic in the sense that investment in mate attraction is matched to the needs of the female. We use the orb-web spider Argiope bruennichi in which females risk the production of unfertilised egg clutches if they do not receive...

  16. Predator-Prey Interactions are Context Dependent in a Grassland Plant-Grasshopper-Wolf Spider Food Chain.

    Science.gov (United States)

    Laws, Angela N; Joern, Anthony

    2015-06-01

    Species interactions are often context dependent, where outcomes vary in response to one or more environmental factors. It remains unclear how abiotic conditions like temperature combine with biotic factors such as consumer density or food quality to affect resource availability or influence species interactions. Using the large grasshopper Melanoplus bivittatus (Say) and a common wolf spider [Rabidosa rabida (Walkenaer)], we conducted manipulative field experiments in tallgrass prairie to examine how spider-grasshopper interactions respond to manipulations of temperature, grasshopper density, and food quality. Grasshopper survival was density dependent, as were the effects of spider presence and food quality in context-dependent ways. In high grasshopper density treatments, predation resulted in increased grasshopper survival, likely as a result of reduced intraspecific competition in the presence of spiders. Spiders had no effect on grasshopper survival when grasshoppers were stocked at low densities. Effects of the experimental treatments were often interdependent so that effects were only observed when examined together with other treatments. The occurrence of trophic cascades was context dependent, where the effects of food quality and spider presence varied with temperature under high-density treatments. Temperature weakly affected the impact of spider presence on M. bivittatus survivorship when all treatments were considered simultaneously, but different context-dependent responses to spider presence and food quality were observed among the three temperature treatments under high-density conditions. Our results indicate that context-dependent species interactions are common and highlight the importance of understanding how key biotic and abiotic factors combine to influence species interactions. PMID:26313957

  17. Black Nuns as Educators.

    Science.gov (United States)

    Rector, Theresa A.

    1982-01-01

    Traces the contributions of Black Roman Catholic nuns to Black education in the United States since the early 1800s. Also shows that, despite declining membership, the three existing religious orders continue to be active in Black education and social change. (GC)

  18. Black Holes in Higher Dimensions (Black Strings and Black Rings)

    CERN Document Server

    Kleihaus, Burkhard

    2016-01-01

    The last three years have again seen new exciting developments in the area of higher dimensional black objects. For black objects with noncompact higher dimensions, the solution space was exlored further within the blackfold approach and with numerical schemes, yielding a large variety of new families of solutions, while limiting procedures created so-called super-entropic black holes. Concerning compact extra dimensions, the sequences of static nonuniform black strings in five and six dimensions were extended to impressively large values of the nonuniformity parameter with extreme numerical precision, showing that an oscillating pattern arises for the mass, the area or the temperature, while approaching the conjectured double-cone merger solution. Besides the presentation of interesting new types of higherdimensional solutions, also their physical properties were addressed in this session. While the main focus was on Einstein gravity, a significant number of talks also covered Lovelock theories.

  19. Nephila clavipes Flagelliform Silk-like GGX Motifs Contribute to Extensibility and Spacer Motifs Contribute to Strength in Synthetic Spider Silk Fibers

    OpenAIRE

    Adrianos, Sherry L.; Teulé, Florence; Hinman, Michael B.; Jones, Justin A.; Weber, Warner S.; Yarger, Jeffery L.; Lewis, Randolph V.

    2013-01-01

    Flagelliform spider silk is the most extensible silk fiber produced by orb weaver spiders, though not as strong as the dragline silk of the spider. The motifs found in the core of the Nephila clavipes flagelliform Flag protein are: GGX, spacer, and GPGGX. Flag does not contain the polyalanine motif known to provide the strength of dragline silk. To investigate the source of flagelliform fiber strength, four recombinant proteins were produced containing variations of the three core motifs of t...

  20. Unique Bell-shaped Voltage-dependent Modulation of Na+ Channel Gating by Novel Insect-selective Toxins from the Spider Agelena orientalis*

    OpenAIRE

    Billen, Bert; Vassilevski, Alexander; Nikolsky, Anton; Debaveye, Sarah; Tytgat, Jan; Grishin, Eugene

    2010-01-01

    Spider venoms provide a highly valuable source of peptide toxins that act on a wide diversity of membrane-bound receptors and ion channels. In this work, we report isolation, biochemical analysis, and pharmacological characterization of a novel family of spider peptide toxins, designated β/δ-agatoxins. These toxins consist of 36–38 amino acid residues and originate from the venom of the agelenid funnel-web spider Agelena orientalis. The presented toxins show considerable amino acid sequence s...

  1. Wild tomato leaf extracts for spider mite and cowpea aphid control.

    Science.gov (United States)

    Antonious, George F; Kamminga, Katherine; Snyder, John C

    2014-01-01

    Glandular trichomes on the leaves of wild tomato, L. hirsutum f. hirsutum Mull, also known as Solanum habrochaites (Solanaceae), synthesize and accumulate high levels of methyl ketones (MKs). L. hirsutum accession LA 407, having high concentration of MKs, was grown from seeds under greenhouse conditions. Four MKs (2-undecanone, 2-dodecanone, 2-tridecanone, and 2-pentadecanone) were screened for their toxicity to spider mites, Tetranychus urticae Koch and cowpea aphids, Aphis craccivora Koch. The objectives of this investigation were to: (1) develop a bioassay for testing MKs on spider mite and cowpea aphid mortality and (2) compare the efficacies of wild tomato leaf crude extracts and pure standard materials of MKs against spider mite and cowpea aphid mortality. Our results revealed that spider mites are most sensitive to 2-tridecanone (LC50 = 0.08 μmole cm(-2) of treated leaf surface) and least sensitive to 2-undecanone (LC50 = 1.5 μmole cm(-2) of treated leaf surface) 4 h after treatment. Similarly, 2-tridecanone caused greatest mortality (LC50 = 0.2 μmole cm(-2) of treated leaf surface), whereas 2-undecanone caused the lowest morality (LC50 = 0.48 μmole cm(-2) of treated surface) of cowpea aphid. We concluded that all MKs tested in this investigation are toxic to spider mites and aphids. 2-Tridecanone is more effective in killing mites and aphids compared to other MKs. Toxicity of crude extracts, prepared from the leaves of L. hirsutum accession LA 407, to spider mites and cowpea aphids revealed greater mortality compared to a combined mixture of MKs standard material (used at the same concentration as found on LA 407 leaves). This indicates that in addition to MKs, other unidentified compounds in LA 407 leaf extract also have pesticidal properties. Accordingly, leaf extracts of LA 407 could be explored in crop protection, and they might open a new area of MK formulations and discovery of biorational alternatives for pest control in agricultural fields. PMID

  2. Spiders (Arachnida: Araneae of the vegetation layer of the Mkambati Nature Reserve, Eastern Cape, South Africa

    Directory of Open Access Journals (Sweden)

    Anna S. Dippenaar-Schoeman

    2011-03-01

    Full Text Available The Pondoland region of the Eastern Cape province, South Africa is very poorly studied with regard to invertebrate diversity, particularly in the case of arachnids. Accordingly, and in view of proposed infrastructural and mining developments in this ecologically sensitive area of high plant endemism, baseline data are provided on spiders (Araneae of the vegetation layer (i.e. excluding the ground-dwelling fauna of the Mkambati Nature Reserve (MNR. Spiders were collected at 26 sites (six forest and 20 grassland sites in the MNR over an eight-day period, using sweep sampling and active searching of flowers in grassland and tree beating in forests, as part of a broader biodiversity survey. Additional specimens were collected with Malaise and pan traps. A total of 1275 specimens were sampled, representing 132 species (6.6% of the total number recorded in South Africa in 103 genera and 29 families. Theridiidae and Araneidae were the most diverse spider families in the reserve, represented by 22 species each (16.7% of the total, followed by Thomisidae with 19 species (14.4% and Salticidae with 18 species (13.6%. Grassland and forest had distinct spider faunas, with only 24.2% of species being recorded from both biomes. The average number of species sampled per site in grassland and forest was 26 species for both habitats, although values for the two biomes are not directly comparable because different sampling methods were used. All 132 species are new records for the reserve, of which 20 were new records for the Eastern Cape and at least eight spider species may be new to science. The spider diversity captured despite temporal and methodological limits indicates that many additional species are likely to occur in the reserve. Conservation implications: If the MNR is not adequately conserved at least five new species, which may be confined to the area, would be at high risk of extinction and 15 other species endemic to the Pondoland and Kwa

  3. Nonstationary analogue black holes

    International Nuclear Information System (INIS)

    We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model see Unruh (1981 Phys. Rev. Lett. 46 1351). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes. We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symmetric nonstationary metrics. (paper)

  4. Black Hole Battery

    Science.gov (United States)

    Levin, Janna; D'Orazio, Daniel

    2016-03-01

    Black holes are dark dead stars. Neutron stars are giant magnets. As the neutron star orbits the black hole, an electronic circuit forms that generates a blast of power just before the black hole absorbs the neutron star whole. The black hole battery conceivably would be observable at cosmological distances. Possible channels for luminosity include synchro-curvature radiation, a blazing fireball, or even an unstable, short-lived black hole pulsar. As suggested by Mingarelli, Levin, and Lazio, some fraction of the battery power could also be reprocessed into coherent radio emission to populate a subclass of fast radio bursts.

  5. Changes in species diversity of arboreal spiders in Mexican coffee agroecosystems: untangling the web of local and landscape influences driving diversity

    Directory of Open Access Journals (Sweden)

    Zachary Hajian-Forooshani

    2014-11-01

    Full Text Available Agricultural intensification is implicated as a major driver of global biodiversity loss. Local management and landscape scale factors both influence biodiversity in agricultural systems, but there are relatively few studies to date looking at how local and landscape scales influence biodiversity in tropical agroecosystems. Understanding what drives the diversity of groups of organisms such as spiders is important from a pragmatic point of view because of the important biocontrol services they offer to agriculture. Spiders in coffee are somewhat enigmatic because of their positive or lack of response to agricultural intensification. In this study, we provide the first analysis, to our knowledge, of the arboreal spiders in the shade trees of coffee plantations. In the Soconusco region of Chiapas, Mexico we sampled across 38 sites on 9 coffee plantations. Tree and canopy connectedness were found to positively influence overall arboreal spider richness and abundance. We found that different functional groups of spiders are responding to different local and landscape factors, but overall elevation was most important variable influencing arboreal spider diversity. Our study has practical management applications that suggest having shade grown coffee offers more suitable habitat for arboreal spiders due to a variety of the characteristics of the shade trees. Our results which show consistently more diverse arboreal spider communities in lower elevations are important in light of looming global climate change. As the range of suitable elevations for coffee cultivation shrinks promoting arboreal spider diversity will be important in sustaining the viability of coffee.

  6. Changes in species diversity of arboreal spiders in Mexican coffee agroecosystems: untangling the web of local and landscape influences driving diversity.

    Science.gov (United States)

    Hajian-Forooshani, Zachary; Gonthier, David J; Marín, Linda; Iverson, Aaron L; Perfecto, Ivette

    2014-01-01

    Agricultural intensification is implicated as a major driver of global biodiversity loss. Local management and landscape scale factors both influence biodiversity in agricultural systems, but there are relatively few studies to date looking at how local and landscape scales influence biodiversity in tropical agroecosystems. Understanding what drives the diversity of groups of organisms such as spiders is important from a pragmatic point of view because of the important biocontrol services they offer to agriculture. Spiders in coffee are somewhat enigmatic because of their positive or lack of response to agricultural intensification. In this study, we provide the first analysis, to our knowledge, of the arboreal spiders in the shade trees of coffee plantations. In the Soconusco region of Chiapas, Mexico we sampled across 38 sites on 9 coffee plantations. Tree and canopy connectedness were found to positively influence overall arboreal spider richness and abundance. We found that different functional groups of spiders are responding to different local and landscape factors, but overall elevation was most important variable influencing arboreal spider diversity. Our study has practical management applications that suggest having shade grown coffee offers more suitable habitat for arboreal spiders due to a variety of the characteristics of the shade trees. Our results which show consistently more diverse arboreal spider communities in lower elevations are important in light of looming global climate change. As the range of suitable elevations for coffee cultivation shrinks promoting arboreal spider diversity will be important in sustaining the viability of coffee. PMID:25392751

  7. Intra-community infanticide and forced copulation in spider monkeys: a multi-site comparison between Cocha Cashu, Peru and Punta Laguna, Mexico.

    Science.gov (United States)

    Gibson, K Nicole; Vick, Laura G; Palma, Ana Cristina; Carrasco, Farah M; Taub, David; Ramos-Fernández, Gabriel

    2008-05-01

    We describe two cases of infanticide, two suspected infanticides, and a forced copulation by familiar resident males in two populations of wild spider monkeys (Ateles belzebuth chamek and A. geoffroyi yucatanensis). These are the first known infanticides and forced copulation in spider monkeys. Data were gathered from four neighboring communities of spider monkeys in Manu National Park at the Cocha Cashu Biological Station, Peru and two communities in the Otoch Ma'ax Yetel Kooh Reserve at Punta Laguna, Mexico, during intensive field studies of over 2,000 hr each. These are rare behaviors, but results suggest that mating history and sexual coercion are important in spider monkey social relationships. PMID:18064591

  8. Black Flowers in Flatland

    CERN Document Server

    Alkac, Gokhan; Tekin, Bayram

    2016-01-01

    Asymptotically flat black holes in $2+1$ dimensions are a rarity. We study the recently found black flower solutions (asymptotically flat black holes with deformed horizons), static black holes, rotating black holes and the dynamical black flowers (black holes with radiative gravitons ) of the purely quadratic version of new massive gravity. We show how they appear in this theory and we also show that they are also solutions to the infinite order extended version of the new massive gravity, that is the Born-Infeld extension of new massive gravity with an amputated Einsteinian piece. The same metrics also solve the topologically extended versions of these theories, with modified conserved charges and the thermodynamical quantities, such as the Wald entropy. Besides these we find new conformally flat radiating type solutions to these extended gravity models. We also show that these metrics do not arise in Einstein's gravity coupled to physical perfect fluids.

  9. Spiders on a Hot Volcanic Roof: Colonisation Pathways and Phylogeography of the Canary Islands Endemic Trap-Door Spider Titanidiops canariensis (Araneae, Idiopidae)

    Science.gov (United States)

    Opatova, Vera; Arnedo, Miquel A.

    2014-01-01

    Studies conducted on volcanic islands have greatly contributed to our current understanding of how organisms diversify. The Canary Islands archipelago, located northwest of the coast of northern Africa, harbours a large number of endemic taxa. Because of their low vagility, mygalomorph spiders are usually absent from oceanic islands. The spider Titanidiops canariensis, which inhabits the easternmost islands of the archipelago, constitutes an exception to this rule. Here, we use a multi-locus approach that combines three mitochondrial and four nuclear genes to investigate the origins and phylogeography of this remarkable trap-door spider. We provide a timeframe for the colonisation of the Canary Islands using two alternative approaches: concatenation and species tree inference in a Bayesian relaxed clock framework. Additionally, we investigate the existence of cryptic species on the islands by means of a Bayesian multi-locus species delimitation method. Our results indicate that T. canariensis colonised the Canary Islands once, most likely during the Miocene, although discrepancies between the timeframes from different approaches make the exact timing uncertain. A complex evolutionary history for the species in the archipelago is revealed, which involves two independent colonisations of Fuerteventura from the ancestral range of T. canariensis in northern Lanzarote and a possible back colonisation of southern Lanzarote. The data further corroborate a previously proposed volcanic refugium, highlighting the impact of the dynamic volcanic history of the island on the phylogeographic patterns of the endemic taxa. T. canariensis includes at least two different species, one inhabiting the Jandia peninsula and central Fuerteventura and one spanning from central Fuerteventura to Lanzarote. Our data suggest that the extant northern African Titanidiops lineages may have expanded to the region after the islands were colonised and, hence, are not the source of colonisation. In

  10. CSTX-9, a toxic peptide from the spider Cupiennius salei: amino acid sequence, disulphide bridge pattern and comparison with other spider toxins containing the cystine knot structure.

    Science.gov (United States)

    Schalle, J; Kämpfer, U; Schürch, S; Kuhn-Nentwig, L; Haeberli, S; Nentwig, W

    2001-09-01

    CSTX-9 (68 residues, 7530.9 Da) is one of the most abundant toxic polypeptides in the venom of the wandering spider Cupiennius salei. The amino acid sequence was determined by Edman degradation using reduced and alkylated CSTX-9 and peptides generated by cleavages with endoproteinase Asp-N and trypsin, respectively. Sequence comparison with CSTX-1, the most abundant and the most toxic polypeptide in the crude spider venom, revealed a high degree of similarity (53% identity). By means of limited proteolysis with immobilised trypsin and RP-HPLC, the cystine-containing peptides of CSTX-9 were isolated and the disulphide bridges were assigned by amino acid analysis, Edman degradation and nanospray tandem mass spectrometry. The four disulphide bonds present in CSTX-9 are arranged in the following pattern: 1-4, 2-5, 3-8 and 6-7 (Cys6-Cys21, Cys13-Cys30, Cys20-Cys48, Cys32-Cys46). Sequence comparison of CSTX-1 with CSTX-9 clearly indicates the same disulphide bridge pattern, which is also found in other spider polypeptide toxins, e.g. agatoxins (omega-AGA-IVA, omega-AGA-IVB, mu-AGA-I and mu-AGA-VI) from Agelenopsis aperta, SNX-325 from Segestria florentina and curtatoxins (CT-I, CT-II and CT-III) from Hololena curta. CSTX-1/CSTX-9 belong to the family of ion channel toxins containing the inhibitor cystine knot structural motif. CSTX-9, lacking the lysine-rich C-terminal tail of CSTX-1, exhibits a ninefold lower toxicity to Drosophila melanogaster than CSTX-1. This is in accordance with previous observations of CSTX-2a and CSTX-2b, two truncated forms of CSTX-1 which, like CSTX-9, also lack the C-terminal lysine-rich tail. PMID:11693532

  11. Bugs as drugs, part two: worms, leeches, scorpions, snails, ticks, centipedes, and spiders.

    Science.gov (United States)

    Cherniack, E Paul

    2011-03-01

    In this second of a two-part series analyzing the evidence for the use of organisms as medicine, the use of a number of different "bugs" (worms, leeches, snails, ticks, centipedes, and spiders) is detailed. Several live organisms are used as treatments: leeches for plastic surgery and osteoarthritis and the helminths Trichuris suis and Necator americanus for inflammatory bowel disease. Leech saliva is the source of a number of anticoagulants, including the antithrombin agent hirudin and its synthetic analogues, which have been approved for human use. Predatory arthropods, such as certain species of snails, spiders, scorpions, centipedes, and ticks provide a trove of potential analgesic peptides in their venom. A synthetic analogue of a snail venom peptide, ziconotide, has been approved for human use and is used as an alternative to opioids in severe pain cases. Arthropods, such as ticks, have venom that contains anticoagulants and centipede venom has a protein that corrects abnormalities in lipid metabolism. PMID:21438646

  12. Female genital mutilation and monandry in an orb-web spider.

    Science.gov (United States)

    Nakata, Kensuke

    2016-02-01

    Monandry, in which a female has only one mating partner during the reproductive period, is established when a female spontaneously refrains from re-mating, or when a partner male interferes with the attempts of a female to mate again. In the latter case, however, females often have countermeasures against males, which may explain why polyandry is ubiquitous. Here, I demonstrate that the genital appendage, or scape, of the female orb-web spider (Cyclosa argenteoalba) is injured after her first mating, possibly by her first male partner. This female genital mutilation (FGM) permanently precludes copulation, and females appear to have no countermeasures. FGM is considered to confer a strong advantage to males in sexual conflicts over the number of female matings, and it may widely occur in spiders. PMID:26911338

  13. 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.

  14. Male adaptations to minimize sexual cannibalism during reproduction in the funnel-web spider Hololena curta.

    Science.gov (United States)

    Xiao, Yong-Hong; Zunic-Kosi, Alenka; Zhang, Long-Wa; Prentice, Thomas R; McElfresh, J Steven; Chinta, Satya P; Zou, Yun-Fan; Millar, Jocelyn G

    2015-12-01

    Males of many spider species risk being attacked and cannibalized while searching for, courting, and mating with conspecific females. However, there are exceptions. We show that the funnel-web spider, Hololena curta, has 3 adaptations that minimize risk to males during courtship and mating, and enhance reproductive success. First, males detected chemical or tactile signals associated with webs of virgin females, and differentiated them from webs of mated females, enabling males to increase encounter rates with virgin females and avoid aggressive mated females. Second, males produced stereotyped vibrational signals during courting which induced female quiescence and suppressed female aggression. Third, when touched by males, sexually receptive females entered a cataleptic state, allowing males to safely approach and copulate. Because males can mate multiple times and the sex ratio in natural populations of H. curta is female biased, overall reproductive output is likely increased by males of this species avoiding sexual cannibalism. PMID:26033974

  15. Electrostatic sensors for SPIDER experiment: Design, manufacture of prototypes, and first tests

    Energy Technology Data Exchange (ETDEWEB)

    Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Spolaore, M.; Serianni, G.; Barzon, A.; Franchin, L.; Pasqualotto, R.; Pomaro, N.; Taliercio, C.; Trevisan, L. [Consorzio RFX, Associazione Euratom-Enea sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Schiesko, L. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, 1533, D-85740 Garching (Germany)

    2014-02-15

    A system of electrostatic sensors has been designed for the SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) experiment, prototype RF source of the ITER NBI (neutral beam injection). A prototype of the sensor system was manufactured and tested at the BATMAN (BAvarian Test MAchine for Negative ions) facility, where the plasma environment is similar to that of SPIDER. Different aspects concerning the mechanical manufacturing and the signal conditioning are presented, among them the RF compensation adopted to reduce the RF effects which could lead to overestimated values of the electron temperature. The first commissioning tests provided ion saturation current values in the range assumed for the design, so the deduced plasma density estimate is consistent with the expected values.

  16. Electrostatic sensors for SPIDER experiment: Design, manufacture of prototypes, and first tests

    Science.gov (United States)

    Brombin, M.; Spolaore, M.; Serianni, G.; Barzon, A.; Franchin, L.; Pasqualotto, R.; Pomaro, N.; Schiesko, L.; Taliercio, C.; Trevisan, L.

    2014-02-01

    A system of electrostatic sensors has been designed for the SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) experiment, prototype RF source of the ITER NBI (neutral beam injection). A prototype of the sensor system was manufactured and tested at the BATMAN (BAvarian Test MAchine for Negative ions) facility, where the plasma environment is similar to that of SPIDER. Different aspects concerning the mechanical manufacturing and the signal conditioning are presented, among them the RF compensation adopted to reduce the RF effects which could lead to overestimated values of the electron temperature. The first commissioning tests provided ion saturation current values in the range assumed for the design, so the deduced plasma density estimate is consistent with the expected values.

  17. Characterization of Phyllosticta hostae causing Phyllosticta leaf spot on spider lily in China

    Directory of Open Access Journals (Sweden)

    Yi Run Hua

    2015-12-01

    Full Text Available Leaf spot disease on the spider lily [Hymenocallis littoralis (Jacq. Salisb.] continues to cause serious problems in China. To confirm the pathogen, the pathogenicity of isolates from diseased leaves was tested according to Koch’s postulates. The isolates were tentatively identified using morphological characteristics and confirmation was done by phylogenetic analysis of the translation elongation factor 1-alpha gene (TEF1, the actin gene (ACT, and internal transcibed spacer (ITS sequences using neighbor-joining (NJ, maximum parsimony (MP, and Bayesian inference (BI methods. The pathogen was identified as Phyllosticta hostae. Molecular analysis indicated very little diversity in the TEF1, ACT, and ITS gene. This is the first report of P. hostae causing leaf spot disease on spider lily in China.

  18. Structural characterization of the major ampullate silk spidroin-2 protein produced by the spider Nephila clavipes.

    Science.gov (United States)

    Santos-Pinto, José Roberto Aparecido Dos; Arcuri, Helen Andrade; Lubec, Gert; Palma, Mario Sergio

    2016-10-01

    Major ampullate spidroin-2 (MaSp2) is one of the most important spider silk protein, but up to now no information is available regarding the post-translational modifications (PTMs) of this protein. A gel-based mass spectrometry strategy using collision-induced dissociation (CID) and electron-transfer dissociation (ETD) fragmentation methods was used to sequence Nephila clavipes MaSp2 (including the N- and C-terminal non-repetitive domains, and the great part of the central core), and to assign a series of post-translational modifications (PTMs) on to the MaSp2 sequence. Two forms of this protein were identified, with different levels of phosphorylation along their sequences. These findings provide a basis for understanding mechanoelastic properties and can support the future design of recombinant spider silk proteins for biotechnological applications. PMID:27208434

  19. Amplitude distributions of the spider heartpulse in response to gravitational stimuli

    Science.gov (United States)

    Finck, A.

    1984-01-01

    The arachnid Nuctenea sclopetaria (Clerck) which possesses a neurogenic heart, measuring the heartbeat is under efferent control through a dorsal nerve arising from a brain center is discussed. It was shown that the heartrate of this spider is also modulated by an afferent input associated with small increments of gravity. A compressive force on the order of 40 micron is sufficient to elicit a threshold change in heart rate for a typical (100mg) spider. This obtains in a hyper-Gz field less than 1.001. The functional relationship between gravity and heartrate is logarithmic between the absolute threshold and at least 1.5 Gz. A model was proposed in which equilibrium and movement are maintained by changes in blood pressure. It is concluded that the arachnid equilibrium system is like a weight detector which employs a hydraulic compensatory mechanism.

  20. 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

    in intra-colony competition with group size. This cost is traded off against survival benefits at the colony level, which appear to be the major factor favouring group living. In the field, many colonies occur at smaller size than expected from the fitness curve, suggesting ecological or life history......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...

  1. Physical characterization of the liquid adhesive from orb-weaving spiders.

    Science.gov (United States)

    Torres, Fernando G; Troncoso, Omar P; Cavalie, Fernando

    2014-01-01

    Orb-weaving spiders produce bioadhesives that are used to capture their prey. In this paper, the physical properties of these adhesives are characterised. The liquid adhesive from Argiope argentata spiders has been studied and the morphological properties of the droplets, including size, shape and volume were determined. An estimation of viscosity and Young's modulus using atomic force microscopy has also been carried out. Morphological characterization confirmed that the liquid adhesive displayed a typical beads-on-a-string (BOAS) morphology on the silk fibres. The experimental data confirmed that the elastic modulus of the liquid adhesive from A. argentata was in the range 20-100kPa which is in agreement with the Dahlquist criterion for adhesives. PMID:24268267

  2. Five new species of the Afrotropical dark sac spider genus Messapus Simon, 1898 (Araneae: Corinnidae).

    Science.gov (United States)

    Haddad, Charles R; Mbo, Zingisile

    2015-01-01

    The Afrotropical dark sac spider genus Messapus Simon, 1898 (Corinnidae: Corinninae) currently only comprises two described species, the type species M. martini Simon, 1898 and M. natalis (Pocock, 1898), which have both recently been redescribed. The leg and setal morphology of Messapus is studied using scanning electron microscopy for the first time, for M. martini and M. tigris sp. n., and additional characters are provided to supplement a recent generic description. Five new species are described in the current paper: M. megae sp. n. (♂ ♀, from Zimbabwe), M. meridionalis sp. n. (♀, from South Africa), M. seiugatus sp. n. (♀, from Guinea), M. tigris sp. n. (♀, from Botswana and Namibia), and M. tropicus sp. n. (♂ ♀, from Democratic Republic of the Congo). All five species are arboreal spiders occurring on bark, lower foliage strata and the canopies of forest and savannah trees. An identification key to the seven species of the genus is provided. PMID:26701488

  3. Nocturnal foraging enhanced by enlarged secondary eyes in a net-casting spider.

    Science.gov (United States)

    Stafstrom, Jay A; Hebets, Eileen A

    2016-05-01

    Animals that possess extreme sensory structures are predicted to have a related extreme behavioural function. This study focuses on one such extreme sensory structure-the posterior median eyes of the net-casting spider Deinopis spinosa. Although past research has implicated the importance of vision in the nocturnal foraging habits of Deinopis, no direct link between vision in the enlarged eyes and nocturnal foraging has yet been made. To directly test the hypothesis that the enlarged posterior median eyes facilitate visually based nocturnal prey capture, we conducted repeated-measures, visual occlusion trials in both natural and laboratory settings. Our results indicate that D. spinosa relies heavily on visual cues detected by the posterior median eyes to capture cursorial prey items. We suggest that the enlarged posterior median eyes benefit D. spinosa not only through increased diet breadth, but also by allowing spiders to remain active solely at night, thus evading predation by diurnal animals. PMID:27194291

  4. The First Record Of The Salticid Spiders Sibianor larae And S. tantulus (Aranei, Salticidae In Ukraine

    Directory of Open Access Journals (Sweden)

    Evtushenko K. V.

    2015-04-01

    Full Text Available Two species of salticid spiders Sibianor larae Logunov, 2000 and S. tantulus (Simon, 1868 were revealed as a result of verification of collected samples from the forest zone of Ukraine. Th e redefined specimens were previously identify ed as S. aurocinctus (Ohlert, 1865. Specimens of S. aurocinctus were not found in the material. Geographic coordinates of localities and description of S. larae and S. tantulus habitats are provided.

  5. First report of in vitro selection of RNA aptamers targeted to recombinant Loxosceles laeta spider toxins

    OpenAIRE

    Sapag, Amalia; Salinas-Luypaert, Catalina; Constenla-Muñoz, Carlos

    2014-01-01

    Background Loxoscelism is the envenomation caused by the bite of Loxosceles spp. spiders. It entails severe necrotizing skin lesions, sometimes accompanied by systemic reactions and even death. There are no diagnostic means and treatment is mostly palliative. The main toxin, found in several isoforms in the venom, is sphingomyelinase D (SMD), a phospholipase that has been used to generate antibodies intended for medical applications. Nucleic acid aptamers are a promising alternative to antibo...

  6. Population genetic evidence for sex-specific dispersal in an inbred social spider.

    Science.gov (United States)

    Smith, Deborah R; Su, Yong-Chao; Berger-Tal, Reut; Lubin, Yael

    2016-08-01

    Dispersal in most group-living species ensures gene flow among groups, but in cooperative social spiders, juvenile dispersal is suppressed and colonies are highly inbred. It has been suggested that such inbred sociality is advantageous in the short term, but likely to lead to extinction or reduced speciation rates in the long run. In this situation, very low levels of dispersal and gene flow among colonies may have unusually important impacts on fitness and persistence of social spiders. We investigated sex-specific differences in dispersal and gene flow among colonies, as reflected in the genetic structure within colonies and populations of the African social spider Stegodyphus dumicola Pocock, 1898 (Eresidae). We used DNA fingerprinting and mtDNA sequence data along with spatial mapping of colonies to compare male and female patterns of relatedness within and among colonies at three study sites. Samples were collected during and shortly after the mating season to detect sex-specific dispersal. Distribution of mtDNA haplotypes was consistent with proliferation of social nests by budding and medium- to long-distance dispersal by ballooning females. Analysis of molecular variance and spatial autocorrelation analyses of AFLPs showed high levels of genetic similarity within colonies, and STRUCTURE analyses revealed that the number of source populations contributing to colonies ranged from one to three. We also showed significant evidence of male dispersal among colonies at one site. These results support the hypothesis that in social spiders, genetic cohesion among populations is maintained by long-distance dispersal of female colony founders. Genetic diversity within colonies is maintained by colony initiation by multiple dispersing females, and adult male dispersal over short distances. Male dispersal may be particularly important in maintaining gene flow among colonies in local populations. PMID:27551398

  7. Intersexual trophic niche partitioning in an ant-eating spider (Araneae: Zodariidae.

    Directory of Open Access Journals (Sweden)

    Stano Pekár

    Full Text Available BACKGROUND: Divergence in trophic niche between the sexes may function to reduce competition between the sexes ("intersexual niche partitioning hypothesis", or may be result from differential selection among the sexes on maximizing reproductive output ("sexual selection hypothesis". The latter may lead to higher energy demands in females driven by fecundity selection, while males invest in mate searching. We tested predictions of the two hypotheses underlying intersexual trophic niche partitioning in a natural population of spiders. Zodarion jozefienae spiders specialize on Messor barbarus ants that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning. METHODOLOGY/PRINCIPAL FINDINGS: Comparative analysis of trophic morphology (the chelicerae and body size of males, females and juveniles demonstrated highly female biased SSD (Sexual Size Dimorphism in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size, and larger than ants captured by juveniles and males. Female fecundity was highly positively correlated with female body mass, which reflects foraging success during the adult stage. Females in laboratory experiments preferred the large ant sub-castes and displayed higher capture efficiency. In contrast, males occupied a different trophic niche and showed reduced foraging effort and reduced prey capture and feeding efficiency compared with females and juveniles. CONCLUSIONS/SIGNIFICANCE: Our data indicate that female-biased dimorphism in trophic morphology and body size correlate with sex-specific reproductive strategies. We propose that intersexual trophic niche partitioning is shaped primarily by fecundity selection in females, and results from sex

  8. The use of mulch to increase Spider (Arachnidae) numbers; a habitat approach to biological insect control

    OpenAIRE

    Manns, Mrs. Hida R.; Murray, D L; Beresford, D. V.

    2008-01-01

    The potential for insect predators to contribute to a biological balance of insect species was explored with mulch. Insects were collected in pitfall traps in outdoor microplots over 3 seasons in southern Ontario, Canada. Treatments varied each season with crops of oats or soybeans, with residue of straw, corn stalks or paperfibre, and with residue tilled in or surface applied. In 2006 at the peak of spider population density there was a significant effect of the plant and the paperfibre r...

  9. Wood Consumption by Geoffroyi’s Spider Monkeys and Its Role in Mineral Supplementation

    OpenAIRE

    Chaves, Oscar M.; Stoner, Kathryn E.; Ángeles-Campos, Sergio; Arroyo-Rodríguez, Víctor

    2011-01-01

    Wood consumption is a rare behavior in frugivorous primates; however, it can be necessary for nutritional balancing as it may provide macro and/or micronutrients that are scarce in the most frequently eaten items (fruits). We tested this hypothesis in six spider monkey (Ateles geoffroyi) communities inhabiting continuous and fragmented rainforests in Lacandona, Mexico. We investigated the importance of both live and decayed wood in the diet of the monkeys, and assessed if wood consumption is ...

  10. SPIDER: A new instrument for fission fragment research at the Los Alamos Neutron Science Center

    OpenAIRE

    Tovesson Fredrik; Arnold Charles; Blakeley Rick; Hecht Adam; Laptev Alexander; Mader Drew; Meierbachtol Krista; Snyder Lucas; White Morgan

    2013-01-01

    The study of fission fragment yields and how they behave as a function of excitation energy provides insight into the process in which they are formed. Fission yields are also important for nuclear applications, as they can be used as a diagnostic tool. A new instrument, SPIDER (Spectrometer for Ion DEtermination in fission Research), is being developed for measuring fission yields as a function of incident neutron energy at the Los Alamos Neutron Science Center. The instrument employs a time...

  11. Seed-specific expression of spider silk protein multimers causes long-term stability

    OpenAIRE

    Nicola eWeichert; Valeska eHauptmann; Christine eHelmold; Udo eConrad

    2016-01-01

    Seeds enable plants to germinate and to grow in situations of limited availability of nutrients. The stable storage of different seed proteins is a remarkable presumption for successful germination and growth. These strategies have been adapted and used in several molecular farming projects. In this study, we explore the benefits of seed-based expression to produce the high molecular weight spider silk protein FLAG using intein-based trans-splicing. Multimers larger than 460 kDa in size are r...

  12. Numerical implementation of multiple peeling theory and its application to spider web anchorages

    OpenAIRE

    Brely, L.; Bosia, F.; Pugno, N. M.

    2015-01-01

    Adhesion of spider web anchorages has been studied in recent years, including the specific functionalities achieved through different architectures. To better understand the delamination mechanisms of these and other biological or artificial fibrillar adhesives, and how their adhesion can be optimized, we develop a novel numerical model to simulate the multiple peeling of structures with arbitrary branching and adhesion angles, including complex architectures. The numerical model is based on ...

  13. [Toxic components of the venom of the cellar spider Segestria florentina].

    Science.gov (United States)

    Sagdiev, N Zh; Valieva, L A; Korneev, A S; Sadykov, A A; Salikhov, Sh I

    1987-08-01

    Two neurotoxins and one insectotoxin have been isolated from venom of the cellar spider Segestria florentina, their homogeneity being proved by disk electrophoresis, isoelectric focusing, and analysis of N-terminal amino acid residues. The neurotoxins are polypeptides with molecular mass about 5000 D. For the insectotoxin, containing 35 amino acid residues with molecular mass 3988 D, the total primary structure is established. PMID:3675645

  14. The multiple disguises of spiders: web colour and decorations, body colour and movement

    OpenAIRE

    Théry, Marc; Casas, Jérôme

    2008-01-01

    Diverse functions have been assigned to the visual appearance of webs, spiders and web decorations, including prey attraction, predator deterrence and camouflage. Here, we review the pertinent literature, focusing on potential camouflage and mimicry. Webs are often difficult to detect in a heterogeneous visual environment. Static and dynamic web distortions are used to escape visual detection by prey, although particular silk may also attract prey. Recent work using physiological models of vi...

  15. Performance of the full size nGEM detector for the SPIDER experiment

    Science.gov (United States)

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

    2016-03-01

    The ITER neutral beam test facility under construction in Padova will host two experimental devices: SPIDER, a 100 kV negative H/D RF beam source, and MITICA, a full scale, 1 MeV deuterium beam injector. SPIDER will start operations in 2016 while MITICA is expected to start during 2019. Both devices feature a beam dump used to stop the produced deuteron beam. Detection of fusion neutrons produced between beam-deuterons and dump-implanted deuterons will be used as a means to resolve the horizontal beam intensity profile. The neutron detection system will be placed right behind the beam dump, as close to the neutron emitting surface as possible thus providing the map of the neutron emission on the beam dump surface. The system uses nGEM neutron detectors. These are Gas Electron Multiplier detectors equipped with a cathode that also serves as neutron-proton converter foil. The cathode is designed to ensure that most of the detected neutrons at a point of the nGEM surface are emitted from the corresponding beamlet footprint (with dimensions of about 40×22 mm2) on the dump front surface. The size of the nGEM detector for SPIDER is 352 mm×200 mm. Several smaller size prototypes have been successfully made in the last years and the experience gained on these detectors has led to the production of the full size detector for SPIDER during 2014. This nGEM has a read-out board made of 256 pads (arranged in a 16×16 matrix) each with a dimension of 22 mm×13 mm. This paper describes the production of this detector and its tests (in terms of beam profile reconstruction capability, uniformity over the active area, gamma rejection capability and time stability) performed on the ROTAX beam-line at the ISIS spallation source (Didcot-UK).

  16. Extraction of Venom and Venom Gland Microdissections from Spiders for Proteomic and Transcriptomic Analyses

    OpenAIRE

    Garb, Jessica E.

    2014-01-01

    Venoms are chemically complex secretions typically comprising numerous proteins and peptides with varied physiological activities. Functional characterization of venom proteins has important biomedical applications, including the identification of drug leads or probes for cellular receptors. Spiders are the most species rich clade of venomous organisms, but the venoms of only a few species are well-understood, in part due to the difficulty associated with collecting minute quantities of venom...

  17. Characterization of Phyllosticta hostae causing Phyllosticta leaf spot on spider lily in China

    OpenAIRE

    Yi Run Hua; Gan Luo Jun; Chen Jing; Xu Xiao Ling

    2015-01-01

    Leaf spot disease on the spider lily [Hymenocallis littoralis (Jacq.) Salisb.] continues to cause serious problems in China. To confirm the pathogen, the pathogenicity of isolates from diseased leaves was tested according to Koch’s postulates. The isolates were tentatively identified using morphological characteristics and confirmation was done by phylogenetic analysis of the translation elongation factor 1-alpha gene (TEF1), the actin gene (ACT), and internal transcibed spacer (ITS) sequence...

  18. Impact of Canopy Openness on Spider Communities: Implications for Conservation Management of Formerly Coppiced Oak Forests.

    Directory of Open Access Journals (Sweden)

    Ondřej Košulič

    Full Text Available Traditional woodland management created a mosaic of differently aged patches providing favorable conditions for a variety of arthropods. After abandonment of historical ownership patterns and traditional management and the deliberate transformation to high forest after World War II, large forest areas became darker and more homogeneous. This had significant negative consequences for biodiversity. An important question is whether even small-scale habitat structures maintained by different levels of canopy openness in abandoned coppiced forest may constitute conditions suitable for forest as well as open habitat specialists. We investigated the effect of canopy openness in former traditionally coppiced woodlands on the species richness, functional diversity, activity density, conservation value, and degree of rareness of epigeic spiders. In each of the eight studied locations, 60-m-long transect was established consisting of five pitfall traps placed at regular 15 m intervals along the gradient. Spiders were collected from May to July 2012. We recorded 90 spider species, including high proportions of xeric specialists (40% and red-listed threatened species (26%. The peaks of conservation indicators, as well as spider community abundance, were shifted toward more open canopies. On the other hand, functional diversity peaked at more closed canopies followed by a rapid decrease with increasing canopy openness. Species richness was highest in the middle of the canopy openness gradient, suggesting an ecotone effect. Ordinations revealed that species of conservation concern tended to be associated with sparse and partly opened canopy. The results show that the various components of biodiversity peaked at different levels of canopy openness. Therefore, the restoration and suitable forest management of such conditions will retain important diversification of habitats in formerly coppiced oak forest stands. We indicate that permanent presence of small

  19. Impact of Canopy Openness on Spider Communities: Implications for Conservation Management of Formerly Coppiced Oak Forests

    Science.gov (United States)

    Košulič, Ondřej; Michalko, Radek; Hula, Vladimír

    2016-01-01

    Traditional woodland management created a mosaic of differently aged patches providing favorable conditions for a variety of arthropods. After abandonment of historical ownership patterns and traditional management and the deliberate transformation to high forest after World War II, large forest areas became darker and more homogeneous. This had significant negative consequences for biodiversity. An important question is whether even small-scale habitat structures maintained by different levels of canopy openness in abandoned coppiced forest may constitute conditions suitable for forest as well as open habitat specialists. We investigated the effect of canopy openness in former traditionally coppiced woodlands on the species richness, functional diversity, activity density, conservation value, and degree of rareness of epigeic spiders. In each of the eight studied locations, 60-m-long transect was established consisting of five pitfall traps placed at regular 15 m intervals along the gradient. Spiders were collected from May to July 2012. We recorded 90 spider species, including high proportions of xeric specialists (40%) and red-listed threatened species (26%). The peaks of conservation indicators, as well as spider community abundance, were shifted toward more open canopies. On the other hand, functional diversity peaked at more closed canopies followed by a rapid decrease with increasing canopy openness. Species richness was highest in the middle of the canopy openness gradient, suggesting an ecotone effect. Ordinations revealed that species of conservation concern tended to be associated with sparse and partly opened canopy. The results show that the various components of biodiversity peaked at different levels of canopy openness. Therefore, the restoration and suitable forest management of such conditions will retain important diversification of habitats in formerly coppiced oak forest stands. We indicate that permanent presence of small-scale improvements

  20. The embryonic development of the central American wandering spider Cupiennius salei

    Directory of Open Access Journals (Sweden)

    Hilbrant Maarten

    2011-06-01

    Full Text Available Abstract Background The spider Cupiennius salei (Keyserling 1877 has become an important study organism in evolutionary and developmental biology. However, the available staging system for its embryonic development is difficult to apply to modern studies, with strong bias towards the earliest developmental stages. Furthermore, important embryonic events are poorly understood. We address these problems, providing a new description of the embryonic development of C. salei. The paper also discusses various observations that will improve our understanding of spider development. Results Conspicuous developmental events were used to define numbered stages 1 to 21. Stages 1 to 9 follow the existing staging system for the spider Achaearanea tepidariorum, and stages 10 to 21 provide a high-resolution description of later development. Live-embryo imaging shows cell movements during the earliest formation of embryonic tissue in C. salei. The imaging procedure also elucidates the encircling border between the cell-dense embryo hemisphere and the hemisphere with much lower cell density (a structure termed 'equator' in earlier studies. This border results from subsurface migration of primordial mesendodermal cells from their invagination site at the blastopore. Furthermore, our detailed successive sequence shows: 1 early differentiation of the precheliceral neuroectoderm; 2 the morphogenetic process of inversion and 3 initial invaginations of the opisthosomal epithelium for the respiratory system. Conclusions Our improved staging system of development in C. salei development should be of considerable value to future comparative studies of animal development. A dense germ disc is not evident during development in C. salei, but we show that the gastrulation process is similar to that in spider species that do have a dense germ disc. In the opisthosoma, the order of appearance of precursor epithelial invaginations provides evidence for the non-homology of the