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Sample records for sub-antarctic sea spiders

  1. Aspects of reproductive ecology and benthic-pelagic coupling in the sub-antarctic sea cucumber Pseudostichopus mollis (Theel)

    Science.gov (United States)

    Morgan, Andrew; Neal, Lance

    2012-07-01

    For deeper regions of the continental shelf environmental cues entraining reproduction in echinoderms are often absent, which contributes to adoption of continuous reproduction, having larger eggs, and a lecithotrophic mode of larval development. In the present study the sub-Antarctic sea cucumber Pseudostichopus mollis from the family Synallactidae was obtained during June (winter) and September (spring) from a depth of approximately 300 m north of the Auckland Islands in an area abundant in biogenic sediments. Samples were processed for body indices and gonad development. Features characteristic of non-continuous reproduction were exhibited. Although a larger egg size was found (212±14 μm), two distinct winter cohorts of oocytes occurred (41-81 and 161-201 μm) and body wall weight fluctuations (7.6% increase in males and 27.5% reduction in females) coincided with changes in gonad indices between sample dates. For males gonad as a proportion of body wall weight decreased from 3.31±0.9 to 2.11±0.37% and for females it increased from 1.59±0.28 to 2.5±0.30%. For both sample dates the gonad of males maintained mature spermatozoa whereas female gonad shifted from mainly recovery and growth of oocytes to growth and advanced growth of mature oocytes. In habitats with low or variable food availability intermittent reproduction is predicted as resources are too low for a high reproductive effort and too erratic for synchrony. A pattern of reproduction where fluctuations in seasonal organic input into an accumulated benthic food source initiates and synchronises gametogenesis for future spawning is proposed.

  2. Air-sea interaction regimes in the sub-Antarctic Southern Ocean and Antarctic marginal ice zone revealed by icebreaker measurements

    Science.gov (United States)

    Yu, Lisan; Jin, Xiangze; Schulz, Eric W.; Josey, Simon A.

    2017-08-01

    This study analyzed shipboard air-sea measurements acquired by the icebreaker Aurora Australis during its off-winter operation in December 2010 to May 2012. Mean conditions over 7 months (October-April) were compiled from a total of 22 ship tracks. The icebreaker traversed the water between Hobart, Tasmania, and the Antarctic continent, providing valuable in situ insight into two dynamically important, yet poorly sampled, regimes: the sub-Antarctic Southern Ocean and the Antarctic marginal ice zone (MIZ) in the Indian Ocean sector. The transition from the open water to the ice-covered surface creates sharp changes in albedo, surface roughness, and air temperature, leading to consequential effects on air-sea variables and fluxes. Major effort was made to estimate the air-sea fluxes in the MIZ using the bulk flux algorithms that are tuned specifically for the sea-ice effects, while computing the fluxes over the sub-Antarctic section using the COARE3.0 algorithm. The study evidenced strong sea-ice modulations on winds, with the southerly airflow showing deceleration (convergence) in the MIZ and acceleration (divergence) when moving away from the MIZ. Marked seasonal variations in heat exchanges between the atmosphere and the ice margin were noted. The monotonic increase in turbulent latent and sensible heat fluxes after summer turned the MIZ quickly into a heat loss regime, while at the same time the sub-Antarctic surface water continued to receive heat from the atmosphere. The drastic increase in turbulent heat loss in the MIZ contrasted sharply to the nonsignificant and seasonally invariant turbulent heat loss over the sub-Antarctic open water.Plain Language SummaryThe icebreaker Aurora Australis is a research and supply vessel that is regularly chartered by the Australian Antarctic Division during the southern summer to operate in waters between Hobart, Tasmania, and Antarctica. The vessel serves as the main lifeline to three permanent research stations on the

  3. New records of Antarctic and Sub-Antarctic sea anemones (Cnidaria, Anthozoa, Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and Scotia Arc.

    Science.gov (United States)

    Rodríguez, Estefanía

    2013-01-01

    Herein we provide new records for 22 Antarctic species of sea anemone sensu lato (Anthozoa: Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and the Scotia Sea. We provided short descriptions, images of the external morphology of preserved specimens (but also of living specimens in most cases), cnida data, and distribution maps for each studied species. New records are presented for nine species in the Weddell Sea and the geographic or bathymetric distributions for 19 of the 22 studied species are extended.

  4. Photosynthesis in a sub-Antarctic shore-zone lichen

    NARCIS (Netherlands)

    Smith, V.; Gremmen, N.J.M.

    2001-01-01

    Photosynthetic responses to moisture, light, temperature, salinity and inorganic nitrogen fertilization are reported for a shore-zone lichen Turgidiusculum complicatulum (formerly Mastodia tesselata), a possible recent introduction to sub-Antarctic Marion Island. Optimum moisture contents for net

  5. X-SEA-F-SPIDER characterization of over octave spanning pulses in the infrared range.

    Science.gov (United States)

    Fan, G; Balčiūnas, T; Fourcade-Dutin, C; Haessler, S; Voronin, A A; Zheltikov, A M; Gérôme, F; Benabid, F; Baltuška, A; Witting, T

    2016-06-13

    We show a practical implementation of a pulse characterization method for sub-cycle pulse measurements in the infrared spectral range based on spectral shearing interferometry. We employ spatially-encoded arrangement filter-based spectral phase interferometry for direct electric field reconstruction with external ancila pulses (X-SEA-F-SPIDER). We show merits and limitations of the setup and an in-depth comparison to another widely used temporal characterization technique - Second-Harmonic Generation Frequency Resolved Optical Gating (SHG-FROG). The X-SEA-F-SPIDER implementation presented in this paper allows measurement of sub-cycle pulses with over one octave wide spectrum spanning the 900-2400 nm range without adding any extra dispersion due to the pulse characterization apparatus.

  6. A record of the sub-Antarctic fur seal Arctocephalus tropicalis in ...

    African Journals Online (AJOL)

    A record of the sub-Antarctic fur seal Arctocephalus tropicalis in Angola. T Carr, Nicole Carr, J.H.M. David. Abstract. Two individuals of the sub-Antarctic fur seal, Arctocephalus tropicalis, one of which was photographed, were seen on the beach 1 km south of the mouth of the Kwanza River, Angola, on 2 October 1983.

  7. Genetic signature of Last Glacial Maximum regional refugia in a circum-Antarctic sea spider

    Science.gov (United States)

    Soler-Membrives, Anna; Linse, Katrin; Miller, Karen J.; Arango, Claudia P.

    2017-10-01

    The evolutionary history of Antarctic organisms is becoming increasingly important to understand and manage population trajectories under rapid environmental change. The Antarctic sea spider Nymphon australe, with an apparently large population size compared with other sea spider species, is an ideal target to look for molecular signatures of past climatic events. We analysed mitochondrial DNA of specimens collected from the Antarctic continent and two Antarctic islands (AI) to infer past population processes and understand current genetic structure. Demographic history analyses suggest populations survived in refugia during the Last Glacial Maximum. The high genetic diversity found in the Antarctic Peninsula and East Antarctic (EA) seems related to multiple demographic contraction-expansion events associated with deep-sea refugia, while the low genetic diversity in the Weddell Sea points to a more recent expansion from a shelf refugium. We suggest the genetic structure of N. australe from AI reflects recent colonization from the continent. At a local level, EA populations reveal generally low genetic differentiation, geographically and bathymetrically, suggesting limited restrictions to dispersal. Results highlight regional differences in demographic histories and how these relate to the variation in intensity of glaciation-deglaciation events around Antarctica, critical for the study of local evolutionary processes. These are valuable data for understanding the remarkable success of Antarctic pycnogonids, and how environmental changes have shaped the evolution and diversification of Southern Ocean benthic biodiversity.

  8. Genetic signature of Last Glacial Maximum regional refugia in a circum-Antarctic sea spider

    Science.gov (United States)

    Soler-Membrives, Anna; Linse, Katrin; Miller, Karen J.

    2017-01-01

    The evolutionary history of Antarctic organisms is becoming increasingly important to understand and manage population trajectories under rapid environmental change. The Antarctic sea spider Nymphon australe, with an apparently large population size compared with other sea spider species, is an ideal target to look for molecular signatures of past climatic events. We analysed mitochondrial DNA of specimens collected from the Antarctic continent and two Antarctic islands (AI) to infer past population processes and understand current genetic structure. Demographic history analyses suggest populations survived in refugia during the Last Glacial Maximum. The high genetic diversity found in the Antarctic Peninsula and East Antarctic (EA) seems related to multiple demographic contraction–expansion events associated with deep-sea refugia, while the low genetic diversity in the Weddell Sea points to a more recent expansion from a shelf refugium. We suggest the genetic structure of N. australe from AI reflects recent colonization from the continent. At a local level, EA populations reveal generally low genetic differentiation, geographically and bathymetrically, suggesting limited restrictions to dispersal. Results highlight regional differences in demographic histories and how these relate to the variation in intensity of glaciation–deglaciation events around Antarctica, critical for the study of local evolutionary processes. These are valuable data for understanding the remarkable success of Antarctic pycnogonids, and how environmental changes have shaped the evolution and diversification of Southern Ocean benthic biodiversity. PMID:29134072

  9. Underwater Optics in Sub-Antarctic and Antarctic Coastal Ecosystems.

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    Pirjo Huovinen

    Full Text Available Understanding underwater optics in natural waters is essential in evaluating aquatic primary production and risk of UV exposure in aquatic habitats. Changing environmental conditions related with global climate change, which imply potential contrasting changes in underwater light climate further emphasize the need to gain insights into patterns related with underwater optics for more accurate future predictions. The present study evaluated penetration of solar radiation in six sub-Antarctic estuaries and fjords in Chilean North Patagonian region (39-44°S and in an Antarctic bay (62°S. Based on vertical diffuse attenuation coefficients (Kd, derived from measurements with a submersible multichannel radiometer, average summer UV penetration depth (z1% in these water bodies ranged 2-11 m for UV-B (313 nm, 4-27 m for UV-A (395 nm, and 7-30 m for PAR (euphotic zone. UV attenuation was strongest in the shallow Quempillén estuary, while Fildes Bay (Antarctica exhibited the highest transparency. Optically non-homogeneous water layers and seasonal variation in transparency (lower in winter characterized Comau Fjord and Puyuhuapi Channel. In general, multivariate analysis based on Kd values of UV and PAR wavelengths discriminated strongly Quempillén estuary and Puyuhuapi Channel from other study sites. Spatial (horizontal variation within the estuary of Valdivia river reflected stronger attenuation in zones receiving river impact, while within Fildes Bay a lower spatial variation in water transparency could in general be related to closeness of glaciers, likely due to increased turbidity through ice-driven processes. Higher transparency and deeper UV-B penetration in proportion to UV-A/visible wavelengths observed in Fildes Bay suggests a higher risk for Antarctic ecosystems reflected by e.g. altered UV-B damage vs. photorepair under UV-A/PAR. Considering that damage repair processes often slow down under cool temperatures, adverse UV impact could be

  10. Submarine geology and geomorphology of active Sub-Antarctic volcanoes: Heard and McDonald Islands

    Science.gov (United States)

    Watson, S. J.; Coffin, M. F.; Whittaker, J. M.; Lucieer, V.; Fox, J. M.; Carey, R.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Martin, T.; Cooke, F.

    2016-12-01

    Heard and McDonald Islands (HIMI) are World Heritage listed sub-Antarctic active volcanic islands in the Southern Indian Ocean. Built atop the Kerguelen Plateau by Neogene-Quaternary volcanism, HIMI represent subaerial exposures of the second largest submarine Large Igneous Province globally. Onshore, processes influencing island evolution include glaciers, weathering, volcanism, vertical tectonics and mass-wasting (Duncan et al. 2016). Waters surrounding HIMI are largely uncharted, due to their remote location. Hence, the extent to which these same processes shape the submarine environment around HIMI has not been investigated. In early 2016, we conducted marine geophysical and geologic surveys around HIMI aboard RV Investigator (IN2016_V01). Results show that volcanic and sedimentary features prominently trend east-west, likely a result of erosion by the eastward flowing Antarctic Circumpolar Current and tidal currents. However, spatial patterns of submarine volcanism and sediment distribution differ substantially between the islands. >70 sea knolls surround McDonald Island suggesting substantial submarine volcanism. Geophysical data reveals hard volcanic seafloor around McDonald Island, whereas Heard Island is characterised by sedimentary sequences tens of meters or more thick and iceberg scours - indicative of glacial processes. Differences in submarine geomorphology are likely due to the active glaciation of Heard Island and differing rock types (Heard: alkali basalt, McDonald: phonolite), and dominant products (clastics vs. lava). Variations may also reflect different magmatic plumbing systems beneath the two active volcanoes (Heard produces larger volumes of more focused lava, whilst McDonald extrudes smaller volumes of more evolved lavas from multiple vents across the edifice). Using geophysical data, corroborated with new and existing geologic data, we present the first geomorphic map revealing the processes that shape the submarine environment around HIMI.

  11. Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand

    DEFF Research Database (Denmark)

    Scott, JM; Turnbull, IM; Sagar, MW

    2015-01-01

    The first comprehensive geological map, a summary of lithologies and new radiogenic isotope data (U–Pb, Rb–Sr) are presented for crystalline rocks of the Sub-Antarctic Snares Islands/Tini Heke, 150 km south of Stewart Island. The main lithology is Snares Granite (c. 109 Ma from U–Pb dating...

  12. Summer diet of the Salvin's prion at sub-Antarctic Marion Island

    African Journals Online (AJOL)

    1988-02-14

    Feb 14, 1988 ... Zoo!. 1988,23(4). 309. Summer diet of the Salvin's prion at sub-Antarctic Marion Island. N.A. Gartshore and W.K. Steele*. Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, 7700 Republic of South Africa. N.T. Klages. Port Elizabeth Museum, P.O. Box 13147, Humewood, ...

  13. Prey and seasonal abundance of killer whales at sub-Antarctic ...

    African Journals Online (AJOL)

    The diet of killer whales Orcinus orca was investigated from 48 predation events observed during sightings at sub-Antarctic Marion Island between 2006 and 2009. From these events, there were 10 cases where prey could be identified. Killer whales fed on fur seals Arctocephalus tropicalis, elephant seals Mirounga leonina ...

  14. Summer diet of the Salvin's prion at sub-Antarctic Marion Island ...

    African Journals Online (AJOL)

    Thirty-nine food samples were collected from Salvin's prions Pachyptila salvini at sub-Antarctic Marion Island, Prince Edward Islands. The diet was dominated by crustaceans which formed 44,2% of the mass, 99,7% of prey items and occurred in 97,4% of the samples. Amphipods were of particular importance, the most ...

  15. New records of Acari from the sub-Antarctic Prince Edward Islands

    NARCIS (Netherlands)

    Marshall, D.J.; Gremmen, N.J.M.; Coetzee, L.; Oconnor, B.M.; Pugh, P.J.A.; Theron, P.D.; Ueckermann, E.A.

    1999-01-01

    Sixty species of Acari are recorded from the sub-Antarctic Marion and Prince Edward Islands (the Prince Edward archipelago). Twenty of the 45 species collected on recent expeditions are new and currently undescribed. Other new taxa include a family of Mesostigmata, four new genera, and the first

  16. Diet of the blue petrel at sub-Antarctic Marion Island | Steele | African ...

    African Journals Online (AJOL)

    Food samples were collected from 49 blue petrels Halobaena caerulea at Marion Island in the sub-Antarctic region. These were analysed and the results compared with previously published data collected at other islands. Crustaceans formed the major prey by mass (59,5%) and frequency (100%), with Euphausia vallentini ...

  17. Controls and variability of solute and sedimentary fluxes in Antarctic and sub-Antarctic Environments

    Science.gov (United States)

    Zwolinski, Zbigniew

    2015-04-01

    The currently prepared SEDIBUD Book on "Source-to-Sink Fluxes in Undisturbed Cold Environments" (edited by Achim A. Beylich, John C. Dixon and Zbigniew Zwolinski and published by Cambridge University Press) is summarizing and synthesizing the achievements of the International Association of Geomorphologists` (I.A.G./A.I.G.) Working Group SEDIBUD (Sediment Budgets in Cold Environments), which has been active since 2005 (http://www.geomorph.org/wg/wgsb.html). The book comprises five parts. One of them is part about sub-Antarctic and Antarctic Environments. This part "Sub-Antarctic and Antarctic Environments" describes two different environments, namely oceanic and continental ones. Each part contains results of research on environmental drivers and rates of contemporary solute and sedimentary fluxes in selected sites. Apart from describing the environmental conditions of the whole continent of Antarctica and sub-Antarctic islands (Zb.Zwolinski, M.Kejna, A.N.Lastochkin, A.Zhirov, S.Boltramovich) this part of the book characterizes terrestrial polar oases free from multi-year ice and snow covers (Zb.Zwolinski). The detailed results of geoecological and sedimentological research come from different parts of Antarctica. Antarctic continental shelf (E.Isla) is an example of sub-Antarctic oceanic environment. South Shetlands, especially King George Island (Zb.Zwolinski, M.Kejna, G.Rachlewicz, I.Sobota, J.Szpikowski), is an example of sub-Antarctic terrestrial environment. Antarctic Peninsula (G.Vieira, M.Francelino, J.C.Fernandes) and surroundings of McMurdo Dry Valleys (W.B.Lyons, K.A.Welch, J.Levy, A.Fountain, D.McKnight) are examples of Antarctic continental environments. The key goals of the Antarctic and sub-Antarctic book chapters are following: (i) identify the main environmental drivers and rates of contemporary solute and sedimentary fluxes, and (ii) model possible effects of projected climate change on solute and sedimentary fluxes in cold climate environments

  18. Sub-Antarctic marine aerosol: dominant contributions from biogenic sources

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    J. Schmale

    2013-09-01

    Full Text Available Biogenic influences on the composition and characteristics of aerosol were investigated on Bird Island (54°00' S, 38°03' W in the South Atlantic during November and December 2010. This remote marine environment is characterised by large seabird and seal colonies. The chemical composition of the submicron particles, measured by an aerosol mass spectrometer (AMS, was 21% non-sea-salt sulfate, 2% nitrate, 8% ammonium, 22% organics and 47% sea salt including sea salt sulfate. A new method to isolate the sea spray signature from the high-resolution AMS data was applied. Generally, the aerosol was found to be less acidic than in other marine environments due to the high availability of ammonia, from local fauna emissions. By positive matrix factorisation five different organic aerosol (OA profiles could be isolated: an amino acid/amine factor (AA-OA, 18% of OA mass, a methanesulfonic acid OA factor (MSA-OA, 25%, a marine oxygenated OA factor (M-OOA, 41%, a sea spray OA fraction (SS-OA, 7% and locally produced hydrocarbon-like OA (HOA, 9%. The AA-OA was dominant during the first two weeks of November and found to be related with the hatching of penguins in a nearby colony. This factor, rich in nitrogen (N : C ratio = 0.13, has implications for the biogeochemical cycling of nitrogen in the area as particulate matter is often transported over longer distances than gaseous N-rich compounds. The MSA-OA was mainly transported from more southerly latitudes where phytoplankton bloomed. The bloom was identified as one of three sources for particulate sulfate on Bird Island, next to sea salt sulfate and sulfate transported from South America. M-OOA was the dominant organic factor and found to be similar to marine OA observed at Mace Head, Ireland. An additional OA factor highly correlated with sea spray aerosol was identified (SS-OA. However, based on the available data the type of mixture, internal or external, could not be determined. Potassium was not

  19. The complete mitochondrial genome of the sea spider Nymphon gracile (Arthropoda: Pycnogonida

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    Braband Anke

    2006-11-01

    Full Text Available Abstract Background Mitochondrial genomes form units of genetic information replicating indepentently from nuclear genomes. Sequence data (most often from protein-coding genes and other features (gene order, RNA secondary structure of mitochondrial genomes are often used in phylogenetic studies of metazoan animals from population to phylum level. Pycnogonids are primarily marine arthropods, often considered closely related to chelicerates (spiders, scorpions and allies. However, due to their aberrant morphology and to controversial results from molecular studies, their phylogenetic position is still under debate. Results This is the first report of a complete mitochondrial genome sequence from a sea spider (Nymphon gracile, class Pycnogonida. Gene order derives from that of other arthropods so that presumably 10 single tRNA gene translocations, a translocation of the mitochondrial control region, and one large inversion affecting protein-coding genes must have happened in the lineage leading to Nymphon gracile. Some of the changes in gene order seem not to be common to all pycnogonids, as those were not found in a partial mitochondrial genome of another species, Endeis spinosa. Four transfer RNAs of Nymphon gracile show derivations from the usual cloverleaf secondary structure (truncation or loss of an arm. Initial phylogenetic analyses using mitochondrial protein-coding gene sequences placed Pycnogonida as sister group to Acari. However, this is in contrast to the majority of all other studies using nuclear genes and/or morphology and was not recovered in a second analysis where two long-branching acarid species were omitted. Conclusion Extensive gene rearrangement characterizes the mitochondrial genome of Nymphon gracile. At least some of the events leading to this derived gene order happened after the split of pycnogonid subtaxa. Nucleotide and amino acid frequencies show strong differences between chelicerate taxa, presumably biasing

  20. Leaf and floral heating in cold climates: do sub-Antarctic megaherbs resemble tropical alpine giants?

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    Lorna Little

    2016-08-01

    Full Text Available High latitude and altitude floras are characterized by low-statured, small, wind-pollinated plants, which mainly reproduce by self-pollination or asexual reproduction. However, at odds with this are some sub-Antarctic islands that have plant species with giant growth forms and large, brightly coloured flowers which require insect visitation for pollination. The size, colour and shape of the inflorescences and leaves of these megaherbs suggest thermal benefits similar to giant tropical alpine plants of equatorial Africa, South America and Hawaii. We evaluated whether heating occurs in sub-Antarctic megaherbs, and to what extent it is related to environmental variables. We measured leaf and inflorescence temperature in six sub-Antarctic megaherb species on Campbell Island, latitude 52.3°S, New Zealand Biological Region. Using thermal imaging techniques, in combination with measurement of solar radiation, ambient air temperature, wind speed, wind chill and humidity, we assessed environmental influences on leaf and floral heating. We found that leaf and inflorescence temperatures of all megaherbs were higher than simultaneously measured ambient temperatures. Greatest heating was seen in Pleurophyllum speciosum, with observed leaves 9°C higher, and inflorescences nearly 11°C higher, than ambient temperature. Heating was highly correlated with brief, unpredictable periods of solar radiation, and occurred most rapidly in species with hairy, corrugated leaves and darkly pigmented, densely packed inflorescences. This is the first evidence that floral and leaf heating occurs in sub-Antarctic megaherbs, and suggests that leaf hairiness, flower colour and shape could provide thermal benefits like those seen in tropical alpine megaherbs.

  1. Aeolian processes and landforms in the sub-Antarctic: preliminary observations from Marion Island

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    David W. Hedding

    2015-11-01

    Full Text Available Sub-Antarctic Marion Island has a hyperoceanic climate, with cold and wet conditions and consistently strong wind velocities throughout the year. Recent observations recognized the increasing role of aeolian processes as a geomorphic agent, and this paper presents the first data for transport by aeolian processes on a sub-Antarctic island. Data were collected through an intensive and high-resolution measurement campaign at three study sites using Big Spring Number Eight sediment traps and surface sediment samplers in conjunction with an array of climatic and soil logger sensors. Observed aeolian landforms are megaripples, and the data suggest that aeolian processes are also modifying solifluction landforms. The sediment traps and sediment samplers collected wind-blown scoria at all three study sites, and the annual (horizontal aeolian sediment flux extrapolated from this preliminary data is estimated at 0.36–3.85 kg cm−2 y−1. Importantly, plant material of various species was trapped during the study that suggests the efficiency of wind for the dispersal of plants in this sub-Antarctic environment may be underestimated. This paper advocates long-term monitoring of aeolian processes and that the link between aeolian processes and synoptic climate must be established. Furthermore, wind as a means to disperse genetic material on Marion Island should be investigated.

  2. Cytotoxic activity of marine sponge extracts from the sub-Antarctic Islands and the Southern Ocean

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    Elisabeth K. Olsen

    2016-11-01

    Full Text Available Over the past 50 years, marine invertebrates, especially sponges, have proven to be a valuable source of new and/or bioactive natural products that have the potential to be further developed as lead compounds for pharmaceutical applications. Although marine benthic invertebrate communities occurring off the coast of South Africa have been explored for their biomedicinal potential, the natural product investigation of marine sponges from the sub-Antarctic Islands in the Southern Ocean for the presence of bioactive secondary metabolites has been relatively unexplored thus far. We report here the results for the biological screening of both aqueous and organic extracts prepared from nine specimens of eight species of marine sponges, collected from around Marion Island and the Prince Edward Islands in the Southern Ocean, for their cytotoxic activity against three cancer cell lines. The results obtained through this multidisciplinary collaborative research effort by exclusively South African institutions has provided an exciting opportunity to discover cytotoxic compounds from sub-Antarctic sponges, whilst contributing to our understanding of the biodiversity and geographic distributions of these cold-water invertebrates. Therefore, we acknowledge here the various contributions of the diverse scientific disciplines that played a pivotal role in providing the necessary platform for the future natural products chemistry investigation of these marine sponges from the sub- Antarctic Islands and the Southern Ocean.

  3. Wiring a periscope--ocelli, retinula axons, visual neuropils and the ancestrality of sea spiders.

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    Tobias Lehmann

    Full Text Available The Pycnogonida or sea spiders are cryptic, eight-legged arthropods with four median ocelli in a 'periscope' or eye tubercle. In older attempts at reconstructing phylogeny they were Arthropoda incertae sedis, but recent molecular trees placed them as the sister group either to all other euchelicerates or even to all euarthropods. Thus, pycnogonids are among the oldest extant arthropods and hold a key position for the understanding of arthropod evolution. This has stimulated studies of new sets of characters conductive to cladistic analyses, e.g. of the chelifores and of the hox gene expression pattern. In contrast knowledge of the architecture of the visual system is cursory. A few studies have analysed the ocelli and the uncommon "pseudoinverted" retinula cells. Moreover, analyses of visual neuropils are still at the stage of Hanström's early comprehensive works. We have therefore used various techniques to analyse the visual fibre pathways and the structure of their interrelated neuropils in several species. We found that pycnogonid ocelli are innervated to first and second visual neuropils in close vicinity to an unpaired midline neuropil, i.e. possibly the arcuate body, in a way very similar to ancestral euarthropods like Euperipatoides rowelli (Onychophora and Limulus polyphemus (Xiphosura. This supports the ancestrality of pycnogonids and sheds light on what eyes in the pycnogonid ground plan might have 'looked' like. Recently it was suggested that arthropod eyes originated from simple ocelli similar to larval eyes. Hence, pycnogonid eyes would be one of the early offshoots among the wealth of more sophisticated arthropod eyes.

  4. Isotachophoretic and immunological analysis of venoms from sea snakes (Laticauda semifasciata) and brown recluse spiders (Loxosceles reclusa) of different morphology, locality, sex, and developmental stages.

    Science.gov (United States)

    Kent, C G; Tu, A T; Geren, C R

    1984-01-01

    Sea snake venom: The venom compositions of sea snakes, Laticauda semifasciata, with different scale patterns were analyzed by isotachophoresis. The comparison showed quantitative rather than qualitative differences. Similarly, L. semifasciata venoms of Philippine and Japanese origins differed only in the quantity of certain proteins. Spider venom: 3. Loxosceles reclusa venom apparatus extract is rich in neutral and acidic proteins but contains relatively small quantities of basic proteins. Differences in venom apparatus extract composition between nymph and adult (male or female) were detected by isotachophoresis. The extracts of male and female venom apparatus were very similar. Extracts of venom apparatus of spiders collected in locations separated by 100 miles were the same.

  5. The complete mitochondrial genome of the sea spider Achelia bituberculata (Pycnogonida, Ammotheidae: arthropod ground pattern of gene arrangement

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    Lee Yong-Seok

    2007-10-01

    Full Text Available Abstract Background The phylogenetic position of pycnogonids is a long-standing and controversial issue in arthropod phylogeny. This controversy has recently been rekindled by differences in the conclusions based on neuroanatomical data concerning the chelifore and the patterns of Hox expression. The mitochondrial genome of a sea spider, Nymphon gracile (Pycnogonida, Nymphonidae, was recently reported in an attempt to address this issue. However, N. gracile appears to be a long-branch taxon on the phylogenetic tree and exhibits a number of peculiar features, such as 10 tRNA translocations and even an inversion of several protein-coding genes. Sequences of other pycnogonid mitochondrial genomes are needed if the position of pycnogonids is to be elucidated on this basis. Results The complete mitochondrial genome (15,474 bp of a sea spider (Achelia bituberculata belonging to the family Ammotheidae, which combines a number of anatomical features considered plesiomorphic with respect to other pycnogonids, was sequenced and characterized. The genome organization shows the features typical of most metazoan animal genomes (37 tightly-packed genes. The overall gene arrangement is completely identical to the arthropod ground pattern, with one exception: the position of the trnQ gene between the rrnS gene and the control region. Maximum likelihood and Bayesian inference trees inferred from the amino acid sequences of mitochondrial protein-coding genes consistently indicate that the pycnogonids (A. bituberculata and N. gracile may be closely related to the clade of Acari and Araneae. Conclusion The complete mitochondrial genome sequence of A. bituberculata (Family Ammotheidae and the previously-reported partial sequence of Endeis spinosa show the gene arrangement patterns typical of arthropods (Limulus-like, but they differ markedly from that of N. gracile. Phylogenetic analyses based on mitochondrial protein-coding genes showed that Pycnogonida may be

  6. Directional Analysis of Sub-Antarctic Climate Change on South Georgia 1905-2009

    Science.gov (United States)

    Sakamoto Ferranti, Emma Jayne; Solera Garcia, Maria Angeles; Timmis, Roger James; Gerrard McKenna, Paul; Whyatt, James Duncan

    2010-05-01

    Directional analysis has been used to study changes in the sub-polar climate of the mountainous and glacierised sub-Antarctic island of South Georgia (54-55°S, 36-38°W). Significantly for climate change studies, South Georgia lies in the Scotia Sea between polar and temperate latitudes, and approximately 1000 km northeast and downwind of the Antarctic Peninsula - one of the fastest-warming regions on Earth (Vaughan et al., 2001). South Georgia was chosen for directional analysis because its climate is substantially advected by predominantly westerly circulations, and because it has a long (since 1905) meteorological record from King Edward Point (KEP) on its eastern side. Additional shorter records from Bird Island at the northwest tip of South Georgia allow comparison between windward (Bird Island) and leeward (KEP) climate regimes. The variation of mountain barrier heights with direction from KEP allows climate changes to be studied under different amounts of orographic influence (from ~700 m to ~2200 m). Records of glacier advance and retreat provide further independent evidence of climate change for comparison with the meteorological record. Directional climate analysis is based on a series of monthly-mean pressure fields defining the orientation and strength of synoptic-scale air-mass advection over the Scotia Sea. These fields are used to define directional climatologies for six 30° sectors with bearings from 150-180° to 300-330°; these sectors encompass 99% of recorded months since 1905. The climatologies summarise the frequencies of air masses from each sector, and the accompanying temperatures and precipitation. The 6 sectors can be broadly associated with 4 air-mass types and source regions: (i) sectors 150-210° advect cold polar maritime air that originated over the Antarctic continent before passing over the Weddell Sea, (ii) sectors 210-270° advect warmer, more stable polar maritime air from the Bellingshausen Sea/Antarctic Peninsula region

  7. Spatial dynamics of two introduced species of carabid beetles on the sub-Antarctic island of South Georgia.

    NARCIS (Netherlands)

    Brandjes, G.J.; Block, W.; Ernsting, G.

    1999-01-01

    On the sub-Antarctic island of South Georgia two species of predatory beetle, Trechisibus antarcticus and Oopterus soledadinus (Coleoptera, Carabidae), were accidentally introduced. The colonisation process offers unique opportunities for testing ecological hypotheses in the field. As a basis for

  8. Impact of the introduced grass Agrostis stolonifera on vegetation and soil fauna communities at Marion Island, sub- Antarctic

    NARCIS (Netherlands)

    Gremmen, N.J.M.; Chown, S.L.; Marshall, D.J.

    1998-01-01

    The grass Agrostis stolonifera L. is the most successful introduced vascular plant at sub-Antarctic Marion Island. Since its accidental introduction, probably in the 1950s, it has spread over the northern half of the island, and presumably will eventually reach all parts of the island. It invades

  9. Distributional records of Antarctic and sub-Antarctic Ophiuroidea from samples curated at the Italian National Antarctic Museum (MNA: check-list update of the group in the Terra Nova Bay area (Ross Sea and launch of the MNA 3D model ‘virtual gallery’

    Directory of Open Access Journals (Sweden)

    Matteo Cecchetto

    2017-10-01

    Full Text Available The distributional records of Ophiuroidea stored at the Italian National Antarctic Museum (MNA, Section of Genoa are presented, corresponding to 1595 individuals that belong to 35 species and 17 genera. Specimens were collected in 106 different sampling stations at depths ranging from 21 to 1652 m in the framework of 14 Antarctic expeditions to the Ross Sea, one to the Antarctic Peninsula, and one to the Falkland Islands (Islas Malvinas. Three species, Amphiura joubini Koehler, 1912, Amphiura (Amphiura angularis Lyman, 1879, and Ophiura flexibilis (Koehler, 1911, are reported as new records for the Terra Nova Bay area, whose check-list of species increases from 15 to 18 species. The determination of these three new records was based both on morphological identification and molecular analyses (COI barcoding. Some of the genetically characterised specimens were also documented through photogrammetry and micro-computed tomography and represent the first bulk of 3D models that will be available through the MNA and Sketchfab websites, both for research and educational purposes.

  10. Head Kidney Transcriptome Analysis and Characterization for the Sub-Antarctic Notothenioid Fish Eleginops maclovinus

    Directory of Open Access Journals (Sweden)

    Danixa Martínez

    2018-01-01

    Full Text Available This study describes de novo transcriptome sequencing and annotation analyses for the head kidney of the sub-Antarctic notothenioid fish Eleginops maclovinus, a sister group of the Antarctic notothenioid fish clade. Moreover, E. maclovinus is one of the most eurythermal and euryhaline representatives of the Notothenioidei suborder. RNA-seq data were generated by the 454 GS Junior system, resulting in 11,207 contigs that were then assembled by the Genomic Workbench CLC software. The transcriptome was annotated by BLASTing each sequence against the universal, non-redundant NCBI database (National Center for Biotechnology Information using the AUSTRAL-omics computer cluster. A significant number of transcripts related to innate and adaptive immunity were found in the sequences, which could be used as references in future immunological studies in E. maclovinus.

  11. The Quarantine Protection of Sub-Antarctic Australia: Two Islands, Two Regimes

    Directory of Open Access Journals (Sweden)

    Sandra Potter

    2007-11-01

    Full Text Available Sub-Antarctic Heard Island and Macquarie Island are among Australia’s offshore properties susceptible to colonization by species introduced by humans. While both islands share World Heritage status and are IUCN Category Ia Protected Areas (Strict Nature Reserves, different quarantine protection regimes are in operation. Macquarie Island’s biosecurity appears to be less catered for while the means and likelihood of introductions are greater. The administrative, political, practical and geographical contexts within which quarantine management planning takes place variously impact on the level of quarantine protection provided to both islands. These and other remote sites of high conservation value are unlikely to receive heightened protection until the issues associated with such management contexts receive greater attention.

  12. Surface destabilisation by the invasive burrowing engineer Mus musculus on a sub-Antarctic island

    Science.gov (United States)

    Eriksson, Bert; Eldridge, David J.

    2014-10-01

    Invasive species are known to have substantial trophic effects on ecosystems and ecosystem processes. The invasion of the house mouse (Mus musculus) onto sub-Antarctic islands has had a devastating effect on plants, invertebrates, and birds with substantial changes in ecosystem functions. Less well understood, however, are the nontrophic, geomorphic effects of mice resulting from their burrowing activities. We examined the extent of burrow construction by M. musculus across an area of about 20 ha on Marion Island and the effects of burrows on water flow and sediment movement. We recorded a density of 0.59 ± 0.48 (mean ± SD) burrows m- 2, with more burrows at lower altitudes and shallower slopes, and twice the density in the solifluction risers (0.86 ± 0.54 m- 2) than the intervening terraces or treads (0.40 ± 0.51 m- 2). Most burrows were dug horizontally into the slope and tended to extend about 20 cm deep before turning. A very conservative estimate of sediment removed from burrows from this depth is 2.4 t ha- 1. However, taking into account more detailed data on burrow morphology based on excavations, actual amounts may be closer to 8.4 t ha- 1. Average soil displacement rate for a single burrow, measured over 5 days, was 0.18 kg burrow- 1 day- 1. Burrows acted as conduits for water and warmer air. Stones at burrow entrances were moved eight times farther by water (10.4 cm) than those not associated with burrows. Similarly, temperatures adjacent to burrow entrances were 4.1 °C higher than sites 10 cm away. Together our data indicate that mice are having substantial deleterious and geomorphic effects on sub-Antarctic ecosystems through their burrowing. With lower rates of mouse mortality resulting from warmer climates predicted under global climate models, we can expect an increase in damage resulting from mouse activity.

  13. Different adaptations of Chinese winter-over expeditioners during prolonged Antarctic and sub-Antarctic residence

    Science.gov (United States)

    Chen, Nan; Wu, Quan; Li, Hao; Zhang, Tao; Xu, Chengli

    2016-05-01

    Prolonged residence in Antarctica is characterized by exposure to isolated, confined, and extreme (ICE) environment. Winter-over expeditioners at research stations often exhibit a complex of psychophysiological symptoms, which varied by stations and sociocultural backgrounds. To understand the different patterns of psychophysiological responses provoked by environmental stress, we conducted a longitudinal assessment of mood and endocrine function in two groups of Chinese expeditioners who were deployed to sub-Antarctic (Great Wall Station, 62°S, N = 12) and Antarctic (Zhongshan Station, 66°S, N = 16) from December 2003 to 2005. Measures of mood, thyroid function, the levels of plasma catecholamine, and circulating interleukins were obtained at departure from China, mid-winter (Antarctica), end of winter (Antarctica), and return to China, respectively. The Zhongshan Station crew experienced significant increases in fatigue, anger, tension, confusion, and decrease in free thyroxine (FT4), norepinephrine (NE), and epinephrine (E) during the winter, increase in thyrotropin (TSH) and total triiodothyronine (TT3) when returning, whereas their counterparts at Great Wall Station only experienced increased TT3 after deployment. Moreover, compared with the Great Wall Station crew, the Zhongshan Station crew exhibited greater increase in anger, greater decrease in FT4, total thyroxine (TT4), NE and E over the winter, and greater increase in TSH when returning. Chinese expeditioners who lived and worked at the Antarctic station and the sub-Antarctic station for over a year showed different change patterns in mood and endocrine hormones. Negative mood and endocrine dysfunction were positively associated with the severity of environment. The study is a supplement to scientific knowledge on psychophysiological variation under ICE environment, which has certain applied value for the development of preventive countermeasures or interventions.

  14. Spider Bites

    Science.gov (United States)

    ... a ruptured appendix. Sweating. Excessive sweating can occur. Brown recluse spider bite The pain associated with a brown ... Sheds Garages Unused pots and gardening equipment Woodpiles Brown recluse habitat Brown recluse spiders are found most commonly ...

  15. Adjustment of pigment composition in Desmarestia (Desmarestiaceae species along a sub-Antarctic to Antarctic latitudinal gradient

    Directory of Open Access Journals (Sweden)

    Andrés Mansilla

    2016-08-01

    Full Text Available Photosynthesis at high latitudes demands efficient strategies of light utilization to maintain algal fitness and performance. The fitness, and physiological adaptation, of a plant or algae species depends in part on the abundance and efficiency of the pigments it can produce to utilize the light resource from its environment. We quantified pigment composition and concentration in six species of the brown macroalgal genus Desmarestia, collected from sub-Antarctic sites (Strait of Magellan, Beagle Channel–Cape Horn Province and sites on the Antarctic Peninsula and adjacent islands. Sub-Antarctic Desmarestia species exhibited lower concentrations of chlorophyll a, chlorophyll c and fucoxanthin than endemic Antarctic species. Antarctic samples of D. menziesii and D. antarctica collected along a decreasing latitudinal gradient showed spatial and interspecific differences in light-harvesting pigment composition. Our results suggest distinct physiological adjustments in Desmarestia species in response to heterogeneous abiotic environmental conditions. The marine sub-Antarctic and Antarctic ecosystems are characterized by harsh environments (e.g., extreme irradiance, photoperiod, temperature, salinity to which the physiology of macroalgal species must adapt.

  16. Assessing Sub-Antarctic Zone primary productivity from fast repetition rate fluorometry

    Science.gov (United States)

    Cheah, Wee; McMinn, Andrew; Griffiths, F. Brian; Westwood, Karen J.; Wright, Simon W.; Molina, Ernesto; Webb, Jason P.; van den Enden, Rick

    2011-11-01

    In situ primary productivity (PP) in the Sub-Antarctic Zone (SAZ) and the Polar Frontal Zone (PFZ) south of Australia was estimated using fast repetition rate fluorometry (FRRF). FRRF-derived PP at Process station 3 (P3) southeast of Tasmania (46°S, 153°E) were higher than P1 in the southwest of Tasmania (46°S, 140°E) and P2 in the Polar Frontal Zone (54°S, 146°E). The FRRF-derived PP rates were well correlated with 14C-uptake rates from one-hour incubations ( r2=0.85, slope=1.23±0.05, plight-limited conditions in deeper waters. Under light-saturated conditions near the surface (0-45 m), the relationship was less clear. This was likely associated with the effects of physiological processes such as cyclic electron flow and the Mehler reaction, which are stimulated at high irradiance. Our results indicate that FRRF can be used to estimate photosynthesis rates in the SAZ and PFZ but to derive an accurate estimation of C-fixation requires a detailed understanding of the physiological properties of the cells and their response to oceanographic parameters under different environmental conditions.

  17. Energy density of sub-Antarctic fishes from the Beagle Channel.

    Science.gov (United States)

    Fernández, D A; Lattuca, M E; Boy, C C; Pérez, A F; Ceballos, S G; Vanella, F A; Morriconi, E R; Malanga, G F; Aureliano, D R; Rimbau, S; Calvo, J

    2009-03-01

    The energy density (ED) of nine species of sub-Antarctic fishes was estimated by calorimetry. The fish, seven notothenioids, one atherinopsid and one galaxiid, represents some of the more abundant species in the ichthyofauna of the Beagle Channel. Principal-components analysis (PCA) of the ED of the different organs/tissues indicated that PC(1) and PC(2) accounted for 87% of the variability. Separation along PC(1) corresponded to differences in muscle and liver energy densities whereas separation along PC(2) corresponded to differences in the ED of the gonads. Differences between species were significant except for P. sima. Inclusion of the gonadosomatic index (GSI) as an explanatory variable enabled us to establish the existence of energy transfer from muscle and liver to the gonads in ripe P. tessellata females. Total ED values varied between 4.21 and 6.26 kJ g(-1), the pelagic Odontesthes sp. being the species with the highest ED. A significant relationship between ED and muscle dry weight (DW(M)) was found for all the species except P. tessellata. These data are the first direct estimates of ED of fishes from the Beagle Channel.

  18. Plant dispersal in the sub-Antarctic inferred from anisotropic genetic structure.

    Science.gov (United States)

    Born, Céline; Le Roux, Peter C; Spohr, Colin; McGeoch, Melodie A; Van Vuuren, Bettine Jansen

    2012-01-01

    Climatic conditions and landscape features often strongly affect species' local distribution patterns, dispersal, reproduction and survival and may therefore have considerable impacts on species' fine-scale spatial genetic structure (SGS). In this study, we demonstrate the efficacy of combining fine-scale SGS analyses with isotropic and anisotropic spatial autocorrelation techniques to infer the impact of wind patterns on plant dispersal processes. We genotyped 1304 Azorella selago (Apiaceae) specimens, a wind-pollinated and wind-dispersed plant, from four populations distributed across sub-Antarctic Marion Island. SGS was variable with Sp values ranging from 0.001 to 0.014, suggesting notable variability in dispersal distance and wind velocities between sites. Nonetheless, the data supported previous hypotheses of a strong NW-SE gradient in wind strength across the island. Anisotropic autocorrelation analyses further suggested that dispersal is strongly directional, but varying between sites depending on the local prevailing winds. Despite the high frequency of gale-force winds on Marion Island, gene dispersal distance estimates (σ) were surprisingly low (<10 m), most probably because of a low pollen dispersal efficiency. An SGS approach in association with isotropic and anisotropic analyses provides a powerful means to assess the relative influence of abiotic factors on dispersal and allow inferences that would not be possible without this combined approach. © 2011 Blackwell Publishing Ltd.

  19. Field experiments on individual adaptation of the spider crab Inachus phalangium to its sea anemone host Anemonia viridis in the northern Adriatic Sea

    Directory of Open Access Journals (Sweden)

    S. LANDMANN

    2015-02-01

    Full Text Available We studied the adaptation of the spider crab Inachus phalangium (Fabricius, 1755 to one of its sea anemone host species, Anemonia viridis (Forsskål, 1775 in the coastal region of Rovinj, Croatia. Similar to other brachyuran species, Inachus spp. generally lives within the anemone to obtain protection from possible predators. Using removal and reintroduction experiments, this study investigates the protection mechanism and shows a loss of adaptation after a period of 10 days when the crabs are taken out of their host and kept solitary. Thirty-nine anemones from two different trial sites were marked individually and the inhabiting crabs were isolated to be released back into their individual hosts later. The reactions of the anemones were closely observed and characterized to determine the respective state of crab adaptation. As 35 out of 39 individuals provoked a defense /attack reaction of the anemone, it is concluded that the crabs possessed some sort of non-permanent protection mechanism that was lost during the test run (chi-square test, p < 0.00014. All tested crabs re-inhabited their host anemones within a maximum of 20 minutes after they had been reintroduced and stung by the anemones. Therefore, habituation to the host’s defense / attack mechanism is acquired individually and not genetically inherent to the species. The results are compared to adaptation and protection data on other decapod crustaceans and some anemonefishes.

  20. The genetic mating system of a sea spider with male-biased sexual size dimorphism: evidence for paternity skew despite random mating success.

    Science.gov (United States)

    Barreto, Felipe S; Avise, John C

    2011-08-01

    Male-biased size dimorphism is usually expected to evolve in taxa with intense male-male competition for mates, and it is hence associated with high variances in male mating success. Most species of pycnogonid sea spiders exhibit female-biased size dimorphism, and are notable among arthropods for having exclusive male parental care of embryos. Relatively little, however, is known about their natural history, breeding ecology, and mating systems. Here we first show that Ammothella biunguiculata, a small intertidal sea spider, exhibits male-biased size dimorphism. Moreover, we combine genetic parentage analysis with quantitative measures of sexual selection to show that male body size does not appear to be under directional selection. Simulations of random mating revealed that mate acquisition in this species is largely driven by chance factors, although actual paternity success is likely non-randomly distributed. Finally, the opportunity for sexual selection (I(s)), an indirect metric for the potential strength of sexual selection, in A. biunguiculata males was less than half of that estimated in a sea spider with female-biased size dimorphism, suggesting the direction of size dimorphism may not be a reliable predictor of the intensity of sexual selection in this group. We highlight the suitability of pycnogonids as model systems for addressing questions relating parental investment and sexual selection, as well as the current lack of basic information on their natural history and breeding ecology. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00265-011-1170-x) contains supplementary material, which is available to authorized users.

  1. Soil calcium availability influences shell ecophenotype formation in the sub-antarctic land snail, Notodiscus hookeri.

    Directory of Open Access Journals (Sweden)

    Maryvonne Charrier

    Full Text Available Ecophenotypes reflect local matches between organisms and their environment, and show plasticity across generations in response to current living conditions. Plastic responses in shell morphology and shell growth have been widely studied in gastropods and are often related to environmental calcium availability, which influences shell biomineralisation. To date, all of these studies have overlooked micro-scale structure of the shell, in addition to how it is related to species responses in the context of environmental pressure. This study is the first to demonstrate that environmental factors induce a bi-modal variation in the shell micro-scale structure of a land gastropod. Notodiscus hookeri is the only native land snail present in the Crozet Archipelago (sub-Antarctic region. The adults have evolved into two ecophenotypes, which are referred to here as MS (mineral shell and OS (organic shell. The MS-ecophenotype is characterised by a thick mineralised shell. It is primarily distributed along the coastline, and could be associated to the presence of exchangeable calcium in the clay minerals of the soils. The Os-ecophenotype is characterised by a thin organic shell. It is primarily distributed at high altitudes in the mesic and xeric fell-fields in soils with large particles that lack clay and exchangeable calcium. Snails of the Os-ecophenotype are characterised by thinner and larger shell sizes compared to snails of the MS-ecophenotype, indicating a trade-off between mineral thickness and shell size. This pattern increased along a temporal scale; whereby, older adult snails were more clearly separated into two clusters compared to the younger adult snails. The prevalence of glycine-rich proteins in the organic shell layer of N. hookeri, along with the absence of chitin, differs to the organic scaffolds of molluscan biominerals. The present study provides new insights for testing the adaptive value of phenotypic plasticity in response to spatial

  2. Terrestrial invasions on sub-Antarctic Marion and Prince Edward Islands

    Directory of Open Access Journals (Sweden)

    Michelle Greve

    2017-03-01

    Full Text Available Background: The sub-Antarctic Prince Edward Islands (PEIs, South Africa’s southernmost territories have high conservation value. Despite their isolation, several alien species have established and become invasive on the PEIs. Objectives: Here we review the invasion ecology of the PEIs. Methods: We summarise what is known about the introduction of alien species, what influences their ability to establish and spread, and review their impacts. Results: Approximately 48 alien species are currently established on the PEIs, of which 26 are known to be invasive. Introduction pathways for the PEIs are fairly well understood – species have mainly been introduced with ship cargo and building material. Less is known about establishment, spread and impact of aliens. It has been estimated that less than 5% of the PEIs is covered by invasive plants, but invasive plants have attained circuminsular distributions on both PEIs. Studies on impact have primarily focussed on the effects of vertebrate invaders, of which the house mouse, which is restricted to Marion Island, probably has the greatest impact on the biodiversity of the islands. Because of the risk of alien introductions, strict biosecurity regulations govern activities at the PEIs. These are particularly aimed at stemming the introduction of alien species, and are likely to have reduced the rates of new introductions. In addition, some effort is currently being made to eradicate selected range-restricted species. However, only one species that had established and spread on the PEIs, the cat, has been successfully eradicated from the islands. Conclusion: Given the ongoing threat of introductions, and the impacts of invaders, it is essential that future invasions to the PEIs are minimised, that the islands’ management policies deal with all stages of the invasion process and that a better understanding of the risks and impacts of invasions is obtained.

  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. Investigation into the impact of storms on sustaining summer primary productivity in the Sub-Antarctic Ocean

    CSIR Research Space (South Africa)

    Nicholson, Sarah-Anne

    2016-09-01

    Full Text Available of such phenomena for ocean-biogeochemical models. 1. Introduction An unexplained peculiarity of phytoplankton blooms in the Southern Ocean (SO) is the regional-scale occur- rence of prolonged blooms into late summer [Swart et al., 2015; Carranza and Gille, 2015...]. Observations of chlorophyll a show that summer blooms are widespread and occur annually [Carranza and Gille, 2015], are prominent within the Sub-Antarctic Zone (SAZ), and may be several months in duration (e.g., ~16weeks in Racault et al. [2012]), typically...

  5. First records of aphid-pathogenic Entomophthorales in the sub-Antarctic archipelagos of Crozet and Kerguelen

    Directory of Open Access Journals (Sweden)

    Bernard Papierok

    2016-07-01

    Full Text Available Since the 20th century, the sub-Antarctic islands have suffered an increasing number of biological invasions. Despite the large number of publications on this topic, there is a lack of knowledge on parasitism rates of invasive species and on the role of parasites and pathogens to regulate their populations. Six aphid species have been introduced in the archipelagos of Crozet (Île de la Possession, 46° 25’ S–51° 51’ E and Kerguelen (49° 21’ S–70° 13’ E. Five of these species were found infected by entomopathogenic fungi of the order Entomophthorales. All these fungal species are cosmopolitan. Conidiobolus obscurus and Entomophthora planchoniana were the most frequently observed on Île de la Possession and in Archipel des Kerguelen, respectively. This is the first report of pathogenic fungi of aphids on the sub-Antarctic islands. We discuss these results in the light of our current knowledge of these insect pathogens. Their introduction by aphids surviving on plants during transportation is the most likely hypothesis to explain their presence on these remote islands.

  6. Biogeography of Antarctic sea anemones (Anthozoa, Actiniaria): What do they tell us about the origin of the Antarctic benthic fauna?

    Science.gov (United States)

    Rodríguez, E.; López-González, P. J.; Gili, J. M.

    2007-08-01

    The present study of the biogeography of the Antarctic sea anemone fauna is based on new records and redescriptions of material collected from the Weddell Sea and Peninsula Antarctica, and on an update of the bibliographic data of the Antarctic and sub-Antarctic regions. The faunal compositions at different levels, the geographic and bathymetric distributions of the sea anemone fauna, and the affinities within the continent and with the sub-Antarctic fauna have been studied. Furthermore, the relationships of the sea anemone fauna, of the Southern Ocean, the Mediterranean Sea and Hawaii have been analysed. In this context, the origin of the Antarctic benthic fauna is discussed.

  7. Effects of summer frost exposures on the cold tolerance strategy of a sub-Antarctic beetle.

    Science.gov (United States)

    Bale, J S.; Worland, M R.; Block, W

    2001-09-01

    The sub-Antarctic beetle Hydromedion sparsutum (Coleoptera, Perimylopidae) is common locally on the island of South Georgia where sub-zero temperatures can be experienced in any month of the year. Larvae were known to be weakly freeze tolerant in summer with a mean supercooling point (SCP) around -4 degrees C and a lower lethal temperature of -10 degrees C (15min exposure). This study investigated the effects of successive freezing exposures on the SCP and subsequent survival of summer acclimatised larvae. The mean SCP of field fresh larvae was -4.2+/-0.2 degrees C with a range from -1.0 to -6.1 degrees C. When larvae were cooled to -6.5 degrees C on 10 occasions at intervals of 30min and one and four days, survival was 44, 70 and 68%, respectively. The 'end of experiment' SCP of larvae surviving 10 exposures at -6.5 degrees C showed distinct changes and patterns from the original field population depending on the interval between exposure. In the 30min interval group, most larvae froze between -6 and -8 degrees C, a depression of up to 6 degrees C from the original sample; all larvae were dead when cooling was continued below the SCP to -12 degrees C. In the one and four day interval groups, most larvae froze above -6 degrees C, showing no change as a result of the 10 exposures at -6.5 degrees C. As with the 30min interval group, some larvae froze below -6 degrees C, but with a wider range, and again, all were dead when cooled to -12 degrees C. However, in the one and four day interval groups, some larvae remained unfrozen when cooled to -12 degrees C, a depression of their individual SCP of at least 6 degrees C, and were alive 24h after cooling. In a further experiment, larvae were cooled to their individual SCP temperature at daily intervals on 10 occasions to ensure that every larva froze every day. Most larvae which showed a depression of their SCP of 2-4 degrees C from their day one value became moribund or died after six or seven freezing events. Survival

  8. The seasonal cycle of mixed layer dynamics and phytoplankton biomass in the Sub-Antarctic Zone: A high-resolution glider experiment

    CSIR Research Space (South Africa)

    Swart, S

    2014-06-01

    Full Text Available -resolution glider data (3 hourly, 2 km horizontal resolution), from~6 months of sampling (spring through summer) in the Sub-Antarctic Zone, is used to assess 1) the different forcing mechanisms driving variability in upper ocean physics and 2) how thesemay...

  9. Contrasting nurse plants and nurse rocks: The spatial distribution of seedlings of two sub-Antarctic species

    Science.gov (United States)

    Haussmann, N. S.; McGeoch, M. A.; Boelhouwers, J. C.

    2010-05-01

    Positive plant interactions, such as those associated with nurse plants, have been suggested to dominate over negative interactions in environments with high abiotic stress. Here we demonstrate that the sub-Antarctic cushion plant species, Azorella selago (Apiaceae), positively affects the distribution of both its own seedlings and those of the perennial grass, Agrostis magellanica (Poaceae). As a result of the light weight and small size of seeds of both species, coupled with strong winds experienced in the study area, we consider it unlikely that these patterns are the result of very localized seed dispersal from the study cushions themselves. Instead, we suggest that both cushions and rocks act as seed traps, trapping seeds dispersed by wind, runoff and/or downslope sediment transport through frost creep. In addition, increased A. selago seedling numbers around cushions, but not around rocks, suggest that cushions provide a biological nurse effect, such as improving soil nutrient status or providing mychorrizae, to seedlings of their own kind.

  10. 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.

  11. Biology of spiders

    National Research Council Canada - National Science Library

    Foelix, Rainer F

    2011-01-01

    "One of the only books to treat the whole spider, from its behavior and physiology to its neurobiology and reproductive characteristics, Biology of Spiders is considered a classic in spider literature...

  12. Time budgets and activity patterns of sub-Antarctic fur seals at ...

    African Journals Online (AJOL)

    1993-04-15

    Antarctic fur seals at Gough Island. M,N, Bester* and ... breeding colony site at Gough Island (40"20'S, gOS4'W) during summer. Time budgets of adult males were ...... The Galapagos sea lion. J. Mammal. 48: 62-69. RAND, R.W. 1967.

  13. A preliminary synoptic assessment of soil frost on Marion Island and the possible consequences of climate change in a maritime sub-Antarctic environment

    Directory of Open Access Journals (Sweden)

    Werner Nel

    2012-03-01

    Full Text Available Located in the sub-Antarctic, Marion Island (46° 54′ S, 37° 45′ E has a distinct periglacial environment that is sensitive to climate change. Diurnal soil frost is the most important geomorphic process occurring on the island and this paper aims to understand the synoptic weather circulation pattern associated with summer soil frost occurrence in a sub-Antarctic environment. Preliminary results from automated microclimate measurements in the interior of Marion Island show that summer soil frost is dependent on Antarctic air mass circulation. This occurs exclusively during post-cyclonic airflow after the passage of a cold front connected to a mid-latitudinal cyclone and subsequent ridging in of the South Atlantic Anticyclone behind the cold front, or when a series of low pressure systems passes over the island. The duration and intensity of soil frost cycles are dependent on the duration of post-cyclonic Antarctic air mass circulation. Summer soil frost on Marion Island is driven by a complex interaction between the latitudinal position of the passing cyclone, the latitudinal position of the ridging anticyclone as well as the trajectory of the air mass circulation. The data suggest that predicted trends in synoptic climate change in the sub-Antarctic may lead to non-linear responses in soil frost dynamics.

  14. Response of phytoplankton photophysiology to varying environmental conditions in the Sub-Antarctic and Polar Frontal Zone.

    Directory of Open Access Journals (Sweden)

    Wee Cheah

    Full Text Available Climate-driven changes are expected to alter the hydrography of the Sub-Antarctic Zone (SAZ and Polar Frontal Zone (PFZ south of Australia, in which distinct regional environments are believed to be responsible for the differences in phytoplankton biomass in these regions. Here, we report how the dynamic influences of light, iron and temperature, which are responsible for the photophysiological differences between phytoplankton in the SAZ and PFZ, contribute to the biomass differences in these regions. High effective photochemical efficiency of photosystem II (F'(q/F'(m0.4, maximum photosynthesis rate (P(B(max, light-saturation intensity (E(k, maximum rate of photosynthetic electron transport (1/[Symbol: see text]PSII, and low photoprotective pigment concentrations observed in the SAZ correspond to high chlorophyll a and iron concentrations. In contrast, phytoplankton in the PFZ exhibits low F'(q/F'(M (~ 0.2 and high concentrations of photoprotective pigments under low light environment. Strong negative relationships between iron, temperature, and photoprotective pigments demonstrate that cells were producing more photoprotective pigments under low temperature and iron conditions, and are responsible for the low biomass and low productivity measured in the PFZ. As warming and enhanced iron input is expected in this region, this could probably increase phytoplankton photosynthesis in this region. However, complex interactions between the biogeochemical processes (e.g. stratification caused by warming could prevent mixing of nutrients, which control phytoplankton biomass and productivity, remain uncertain.

  15. Landscape mapping at sub-Antarctic South Georgia provides a protocol for underpinning large-scale marine protected areas

    Science.gov (United States)

    Hogg, Oliver T.; Huvenne, Veerle A. I.; Griffiths, Huw J.; Dorschel, Boris; Linse, Katrin

    2016-10-01

    Global biodiversity is in decline, with the marine environment experiencing significant and increasing anthropogenic pressures. In response marine protected areas (MPAs) have increasingly been adopted as the flagship approach to marine conservation, many covering enormous areas. At present, however, the lack of biological sampling makes prioritising which regions of the ocean to protect, especially over large spatial scales, particularly problematic. Here we present an interdisciplinary approach to marine landscape mapping at the sub-Antarctic island of South Georgia as an effective protocol for underpinning large-scale (105-106  km2) MPA designations. We have developed a new high-resolution (100 m) digital elevation model (DEM) of the region and integrated this DEM with bathymetry-derived parameters, modelled oceanographic data, and satellite primary productivity data. These interdisciplinary datasets were used to apply an objective statistical approach to hierarchically partition and map the benthic environment into physical habitats types. We assess the potential application of physical habitat classifications as proxies for biological structuring and the application of the landscape mapping for informing on marine spatial planning.

  16. Habitat associations and distribution of the hyperbenthic shrimp, Nauticaris marionis, around the sub-Antarctic Prince Edward Islands

    Science.gov (United States)

    Haley, Craig; von der Meden, Charles; Atkinson, Lara; Reed, Cecile

    2017-09-01

    The association of organisms with particular habitats and habitat-forming organisms, can strongly influence species distributions, interactions and wider ecosystem services. At the sub-Antarctic Prince Edward Islands, the caridean shrimp Nauticaris marionis is a principal part of the benthic ecosystem, occurring between ca. 50 m and 600 m. Its role as a trophic link between the primary productivity and higher predators is established, but little is understood of its in situ habitat usage and associations or of how these structure patterns of abundance. We investigated these aspects directly using a benthic camera sled, sampling 27 stations between 50 m and 500 m. Substratum type was characterised, and estimates of percentage cover of the 13 main groups of habitat-forming epibenthic taxa were made, alongside absolute counts of N. marionis within 'digital quadrats' drawn from 300 m transects. The distribution of N. marionis was influenced by depth, substratum type and overall biogenic cover, being limited to habitats between 50 and 160 m depth on mud or gravel substrata only, and having > 50% biogenic cover. The presence/absence of N. marionis related to significantly different epibenthic assemblages (termed biogenic habitats), but this effect was contingent on depth. Likewise, densities of N. marionis were significantly affected by biogenic habitat type, identifying an association with two biogenic habitat groups, one dominated by red-algae, the other by structurally complex bryozoan species. These associations likely relate to the structural complexity of the two habitat groups, rather than the specific taxa involved. The apparent absence of N. marionis at depths > 160 m contrasts with earlier records and poses questions about the trophic importance of the shrimp in deeper habitats.

  17. Dispersal in the sub-Antarctic: king penguins show remarkably little population genetic differentiation across their range.

    Science.gov (United States)

    Clucas, Gemma V; Younger, Jane L; Kao, Damian; Rogers, Alex D; Handley, Jonathan; Miller, Gary D; Jouventin, Pierre; Nolan, Paul; Gharbi, Karim; Miller, Karen J; Hart, Tom

    2016-10-13

    Seabirds are important components of marine ecosystems, both as predators and as indicators of ecological change, being conspicuous and sensitive to changes in prey abundance. To determine whether fluctuations in population sizes are localised or indicative of large-scale ecosystem change, we must first understand population structure and dispersal. King penguins are long-lived seabirds that occupy a niche across the sub-Antarctic zone close to the Polar Front. Colonies have very different histories of exploitation, population recovery, and expansion. We investigated the genetic population structure and patterns of colonisation of king penguins across their current range using a dataset of 5154 unlinked, high-coverage single nucleotide polymorphisms generated via restriction site associated DNA sequencing (RADSeq). Despite breeding at a small number of discrete, geographically separate sites, we find only very slight genetic differentiation among colonies separated by thousands of kilometers of open-ocean, suggesting migration among islands and archipelagos may be common. Our results show that the South Georgia population is slightly differentiated from all other colonies and suggest that the recently founded Falkland Island colony is likely to have been established by migrants from the distant Crozet Islands rather than nearby colonies on South Georgia, possibly as a result of density-dependent processes. The observed subtle differentiation among king penguin colonies must be considered in future conservation planning and monitoring of the species, and demographic models that attempt to forecast extinction risk in response to large-scale climate change must take into account migration. It is possible that migration could buffer king penguins against some of the impacts of climate change where colonies appear panmictic, although it is unlikely to protect them completely given the widespread physical changes projected for their Southern Ocean foraging grounds

  18. Thermal preference and performance in a sub-Antarctic caterpillar: A test of the coadaptation hypothesis and its alternatives.

    Science.gov (United States)

    Haupt, Tanya M; Sinclair, Brent J; Chown, Steven L

    2017-04-01

    Physiological ecologists have long assumed that thermoregulatory behaviour will evolve to optimise physiological performance. The coadaptation hypothesis predicts that an animal's preferred body temperature will correspond to the temperature at which its performance is optimal. Here we use a strong inference approach to examine the relationship between thermal preference and locomotor performance in the caterpillars of a wingless sub-Antarctic moth, Pringleophaga marioni Viette (Tineidae). The coadaptation hypothesis and its alternatives (suboptimal is optimal, thermodynamic effect, trait variation) are tested. Compared to the optimal movement temperature (22.5°C for field-fresh caterpillars and 25, 20, 22.5, 25 and 20°C following seven day acclimations to 0, 5, 10, 15 and 5-15°C respectively), caterpillar thermal preference was significantly lower (9.2°C for field-fresh individuals and 9.4, 8.8, 8.1, 5.2 and 4.6°C following acclimation to 0, 5, 10, 15 and 5-15°C, respectively). Together with the low degree of asymmetry observed in the performance curves, and the finding that acclimation to high temperatures did not result in maximal performance, all, but one of the above hypotheses (i.e. 'trait variation') was rejected. The thermal preference of P. marioni caterpillars more closely resembles temperatures at which survival is high (5-10°C), or where feeding is optimal (10°C), than where locomotion speed is maximal, suggesting that thermal preference may be optimised for overall fitness rather than for a given trait. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Investigating the turbulence response of a 1-D idealized water column located in the sub-Antarctic zone with focus on the upper ocean dynamics

    CSIR Research Space (South Africa)

    Boodhraj, Kirodh

    2017-09-01

    Full Text Available discussed. 40 41 Data and Method 42 This study focussed on the sub-Antarctic zone of the 43 Southern Ocean region off the coast of South Africa (47ºS 44 4.5ºE), chosen due to the availability of in situ glider data. 45 A configuration (named SAZ1D... 107 of glider data (Swart et al. 2015) obtained from the region. 108 The winter deep mixing penetrates down to 150 𝑚 (above 109 the permanent pycnocline) while during the summer 110 stratification, high temperatures penetrate down to 100 𝑚. 111...

  20. Egg masses of the Patagonian squid Doryteuthis (Amerigo gahi attached to giant kelp (Macrocystis pyrifera in the sub-Antarctic ecoregion

    Directory of Open Access Journals (Sweden)

    Sebastián Rosenfeld

    2014-11-01

    Full Text Available Egg masses of the Patagonian squid Doryteuthis (Amerigo gahi attached to giant kelp (Macrocystis pyrifera in the Magellanic channels of the sub-Antarctic ecoregion in southern South America is documented for the first time. Of seven egg masses observed between 2008 and 2011, one was taken to the laboratory to be analysed and photographed. Comprising long transparent capsules containing eggs, the masses were strongly attached to the stipes of M. pyrifera. This macroalgae is a potentially important economic resource due to its multiple industrial uses; this study shows that it also serves an important ecological role as a spawning substrate for D. gahi.

  1. Spider Bites (For Parents)

    Science.gov (United States)

    ... but are rare. Signs and Symptoms Of a brown recluse spider bite: red blister in the center with ... you think your child was bitten by a brown recluse or black widow spider Think Prevention! Make sure ...

  2. Spider Bites: First Aid

    Science.gov (United States)

    ... stiffness Severe abdominal pain or cramping Excessive sweating Brown recluse spider The brown recluse spider has a violin-shaped marking on its ... and southern states. Signs and symptoms of a brown recluse spider bite vary but may include: At first, ...

  3. Nutritional Immunity Triggers the Modulation of Iron Metabolism Genes in the Sub-Antarctic Notothenioid Eleginops maclovinus in Response to Piscirickettsia salmonis

    Directory of Open Access Journals (Sweden)

    Danixa Martínez

    2017-09-01

    Full Text Available Iron deprivation is a nutritional immunity mechanism through which fish can limit the amount of iron available to invading bacteria. The aim of this study was to evaluate the modulation of iron metabolism genes in the liver and brain of sub-Antarctic notothenioid Eleginops maclovinus challenged with Piscirickettsia salmonis. The specimens were inoculated with two P. salmonis strains: LF-89 (ATCC® VR-1361™ and Austral-005 (antibiotic resistant. Hepatic and brain samples were collected at intervals over a period of 35 days. Gene expression (by RT-qPCR of proteins involved in iron storage, transport, and binding were statistically modulated in infected fish when compared with control counterparts. Specifically, the expression profiles of the transferrin and hemopexin genes in the liver, as well as the expression profiles of ferritin-M, ferritin-L, and transferrin in the brain, were similar for both experimental groups. Nevertheless, the remaining genes such as ferritin-H, ceruloplasmin, hepcidin, and haptoglobin presented tissue-specific expression profiles that varied in relation to the injected bacterial strain and sampling time-point. These results suggest that nutritional immunity could be an important immune defense mechanism for E. maclovinus against P. salmonis injection. This study provides relevant information for understanding iron metabolism of a sub-Antarctic notothenioid fish.

  4. South Atlantic sea surface temperature anomalies and air-sea interactions: stochastic models

    Directory of Open Access Journals (Sweden)

    S. G. Dobrovolski

    1994-08-01

    Full Text Available Data on the South Atlantic monthly sea surface temperature anomalies (SSTA are analysed using the maximum-entropy method. It is shown that the Markov first-order process can describe, to a first approximation, SSTA series. The region of maximum SSTA values coincides with the zone of maximum residual white noise values (sub-Antarctic hydrological front. The theory of dynamic-stochastic climate models is applied to estimate the variability of South Atlantic SSTA and air-sea interactions. The Adem model is used as a deterministic block of the dynamic-stochastic model. Experiments show satisfactorily the SSTA intensification in the sub-Antarctic front zone, with appropriate standard deviations, and demonstrate the leading role of the abnormal drift currents in these processes.

  5. Extensive lake sediment coring survey on Sub-Antarctic Indian Ocean Kerguelen Archipelago (French Austral and Antarctic Lands)

    Science.gov (United States)

    Arnaud, Fabien; Fanget, Bernard; Malet, Emmanuel; Poulenard, Jérôme; Støren, Eivind; Leloup, Anouk; Bakke, Jostein; Sabatier, Pierre

    2016-04-01

    Recent paleo-studies revealed climatic southern high latitude climate evolution patterns that are crucial to understand the global climate evolution(1,2). Among others the strength and north-south shifts of westerlies wind appeared to be a key parameter(3). However, virtually no lands are located south of the 45th South parallel between Southern Georgia (60°W) and New Zealand (170°E) precluding the establishment of paleoclimate records of past westerlies dynamics. Located around 50°S and 70°E, lost in the middle of the sub-Antarctic Indian Ocean, Kerguelen archipelago is a major, geomorphologically complex, land-mass that is covered by hundreds lakes of various sizes. It hence offers a unique opportunity to reconstruct past climate and environment dynamics in a region where virtually nothing is known about it, except the remarkable recent reconstructions based on a Lateglacial peatbog sequence(4). During the 2014-2015 austral summer, a French-Norwegian team led the very first extensive lake sediment coring survey on Kerguelen Archipelago under the umbrella of the PALAS program supported by the French Polar Institute (IPEV). Two main areas were investigated: i) the southwest of the mainland, so-called Golfe du Morbihan, where glaciers are currently absent and ii) the northernmost Kerguelen mainland peninsula so-called Loranchet, where cirque glaciers are still present. This double-target strategy aims at reconstructing various independent indirect records of precipitation (glacier advance, flood dynamics) and wind speed (marine spray chemical species, wind-borne terrigenous input) to tackle the Holocene climate variability. Despite particularly harsh climate conditions and difficult logistics matters, we were able to core 6 lake sediment sites: 5 in Golfe du Morbihan and one in Loranchet peninsula. Among them two sequences taken in the 4km-long Lake Armor using a UWITEC re-entry piston coring system by 20 and 100m water-depth (6 and 7m-long, respectively). One

  6. Brown recluse spider envenomation.

    Science.gov (United States)

    Furbee, R Brent; Kao, Louise W; Ibrahim, Danyal

    2006-03-01

    Brown recluse spider bite is a common diagnosis in almost every state in America. In fact, cases have been reported in areas where the spider has never been seen. A review of medical literature reveals that most current concepts regarding brown recluse spider envenomation are based on supposition. In this article, we attempt to review critically our present understanding of brown recluse bites with a focus on the published evidence.

  7. Observed Temporal and Spatial Variability in the Marine Environment at the Sub-Antarctic Prince Edward Islands - Evidence of a Changing Climate?

    Science.gov (United States)

    Asdar, S.; Deshayes, J.; Ansorge, I. J.

    2016-02-01

    The sub-Antarctic Prince Edward Islands (PEI) (47°S,38°E) are classified as isolated, hostile, impoverished regions, in which the terrestrial and marine ecosystems are relatively simple and extremely sensitive to perturbations. Their location between the Sub-Antarctic Front (SAF) and the Antarctic Polar Front (APF), bordering the Antarctic Circumpolar Current (ACC) provides an ideal natural laboratory for studying how organisms, ecological processes and ecosystems respond to a changing ocean climate in the Southern Ocean. Recent studies have proposed that climate changes reported at the PEI may correspond in time to a southward shift of the ACC and in particular of the SAF. This southward migration in the geographic position is likely to coincide with dramatic changes in the distribution of species and total productivity of this region. This study focuses on the inter-comparison of observations available at these islands. Using spectral analysis which is a study of the frequency domain characteristics of a process, we first determine the dominant characteristics of both the temporal and spatial variability of physical and biogeochemical properties. In doing so the authors are able to determine whether and how these indices of variability interact with one another in order to understand better the mechanisms underpinning this variability, i.e. the seasonal zonal migrations associated with the SAF. Additionally, we include in our analysis recent data from 2 ADCP moorings deployed between the islands from 2014 to 2015. These in-situ observations of circulation and hydrography in the vicinity of the islands provide a unique opportunity to establish a better understanding of how large scale climatic variability may impact local conditions, and more importantly its influence on the fragile ecosystem surrounding the PEI.

  8. Spider's microstructure for sensing.

    Science.gov (United States)

    Jiang, Hui; Li, Hongxiang; Yang, Xianjin; Liu, Yongchang; Hu, Wenping

    2006-01-01

    The spider is well known for sensing the movements of air and preys. Bionics of the spider based on this principle is being paid great attention by many researchers. Here, this paper presents some detailed organs of the spider to make an attempt to clarify the sensing mechanism of the spider from the point view of physical structure by scanning electron microscopy. And behavior characteristics concerning sensing action are observed by optical microscopy. Compared with structures, some novel features of sense movements in micro- and nano-scale size and corresponding possible models are presented. At the same time, simple structure analysis is made to explain and prove this hypothesis.

  9. Crustose corallinaceous algae (Rhodophyta) of the New Zealand and United States scientific expedition to the Ross Sea, Balleny Islands, and Macquarie Ridge, 1965

    NARCIS (Netherlands)

    Zaneveld, Jacques S.; Sanford, Robert B.

    1980-01-01

    Fourteen taxa of crustose Corallinaceae are described from a collection of marine algae picked up in Antarctic and sub-Antarctic waters along a Ross Sea — Balleny Islands — Macquarie Island traject aboard the USS Glacier in 1965. Three of these taxa are newly described, i.e. Lithothamnium

  10. Bat predation by spiders.

    Directory of Open Access Journals (Sweden)

    Martin Nyffeler

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

  11. Bat Predation by Spiders

    Science.gov (United States)

    Nyffeler, Martin; Knörnschild, Mirjam

    2013-01-01

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

  12. Description of Pseudingolfiella possessionis n. sp. (Crustacea, Amphipoda) from sub-Antarctic Île de La Possession, Crozet archipelago: the second freshwater amphipod known from the Antarctic biome, a human introduction of Gondwanan ancestry?

    Science.gov (United States)

    Smet, Willem H De

    2015-03-31

    A new species of freshwater amphipod, Pseudingolfiella possessionis n. sp. (Senticaudata, Pseudingolfiellidae), is described from the submerged moss vegetation of small brooklets at sub-Antarctic Île de La Possession, Crozet archipelago. It constitutes the second freshwater amphipod species known for the sub-Antarctic and Antarctic region, and the fourth member of the genus. The main characters distinguishing it from all congeners are: the spine on the posterior margin of the dactylus, incisor and lamina mobilis of mandible each with 5 teeth, the setation of the maxilliped, the vestigial second article of pleopod 3 in the female, the undulate and laterally notched posterolateral margin of the external ramus of uropods 1 and 2 in the male, the spinulate dorsomedian projection of the telson.

  13. Organic matter characterization and decomposition dynamics in sub-Antarctic streams impacted by invasive beavers Caracterización de la materia orgánica y la dinámica de descomposición en arroyos subantárticos impactados por castores invasores

    OpenAIRE

    Erica Ulloa; Anderson, Christopher B.; Marcelo Ardón; Silvia Murcia; Alejandro E.J Valenzuela

    2012-01-01

    Despite being a relatively remote and well conserved area, the sub-Antarctic ecoregion faces pressing global threats from climate change, the ozone hole and introduced species. Its freshwater ecosystems are one of the least studied components of this biome, but they are known to confront a host of invasive taxa including trout and beavers. We set out to understand the basic characterization and dynamics of organic matter processing and decomposition in sub-Antarctic streams under natural fore...

  14. Brown recluse spider (image)

    Science.gov (United States)

    The brown recluse is a venomous spider most commonly found in midwestern and southern states of the United States. It ... inch overall and has long skinny legs. The brown recluse is brown with a characteristic dark violin-shaped ...

  15. Brown Recluse Spider

    Science.gov (United States)

    ... 6.4-19.1mm) • Color: Golden brown • A dark violin/fiddle shape (see top photo) is located ... Habitat The Brown Recluse Spider builds small retreat webs behind objects of any type. Symptoms • The severity ...

  16. New findings and a new species of the genus Ammothea (Pycnogonida, Ammotheidae), with an updated identification key to all Antarctic and sub-Antarctic species

    Science.gov (United States)

    Cano-Sánchez, E.; López-González, P. J.

    2014-03-01

    Specimens of the pycnogonid genus Ammothea collected during the Polarstern cruise XXIII/8 (23 November 2006-30 January 2007) were studied. Nine species were recognized in this collection: Ammothea bentartica, A. bicorniculata, A. carolinensis, A. clausi, A. longispina, A. minor, A. spinosa, A. striata and A. tibialis. Three of them ( A. bentartica, A. bicorniculata and A. tibialis) are reported for the second time, enlarging their known geographical and bathymetric range. In the present contribution, the observed morphological variability of all collected Ammothea species is described and discussed. For the identification and description of the material, different museum specimens were consulted. Among them, we have consulted part of the Discovery collection housed at the Natural History Museum in London. That material was initially identified by Isabella Gordon, a reputed author in the field of pycnogonid taxonomy. A new species, based on a museum specimen previously highly confused in the literature, is proposed in the present contribution as Ammothea isabellae n. sp. The new taxon is compared with its closest congeners, especially with A. longispina and A. stylirostris. Finally, we propose an updated dichotomous key to species covering all currently known Antarctic and sub-Antarctic Ammothea species.

  17. Recovering greater fungal diversity from pristine and diesel fuel contaminated Sub-Antarctic soil through cultivation using a high and a novel low nutrient approach

    Directory of Open Access Journals (Sweden)

    Belinda Carlene Ferrari

    2011-11-01

    Full Text Available Novel cultivation strategies for bacteria are widespread and are well described for recovering greater diversity from the hitherto unculturable majority. While similar approaches have not been demonstrated for fungi it has been suggested that of the 1.5 million estimated species less than 5% have been recovered into pure culture. Fungi are known to be involved in many degradative processes, including the breakdown of hydrocarbons, and it has been speculated that in Polar Regions they contribute significantly to bioremediation of soils contaminated with hydrocarbons. Given the biotechnological potential of fungi there is a need to increase efforts for greater species recovery, particularly from extreme environments such as sub-Antarctic Macquarie Island. In this study, like the hitherto unculturable bacteria, high concentrations of nutrients selected for predominantly different species to that recovered using low nutrient media. By combining both approaches to cultivation from contaminated and non-contaminated soils, 99 fungal species were recovered, including 42 yet unidentified species, several of which were isolated from soils containing high concentrations of diesel fuel. These novel species will now be characterized for their potential role in hydrocarbon degradation.

  18. Extraction and characterization of collagen from Antarctic and Sub-Antarctic squid and its potential application in hybrid scaffolds for tissue engineering.

    Science.gov (United States)

    Coelho, Rui C G; Marques, Ana L P; Oliveira, Sara M; Diogo, Gabriela S; Pirraco, Rogério P; Moreira-Silva, Joana; Xavier, José C; Reis, Rui L; Silva, Tiago H; Mano, João F

    2017-09-01

    Collagen is the most abundant protein found in mammals and it exhibits a low immunogenicity, high biocompatibility and biodegradability when compared with others natural polymers. For this reason, it has been explored for the development of biologically instructive biomaterials with applications for tissue substitution and regeneration. Marine origin collagen has been pursued as an alternative to the more common bovine and porcine origins. This study focused on squid (Teuthoidea: Cephalopoda), particularly the Antarctic squid Kondakovia longimana and the Sub-Antarctic squid Illex argentinus as potential collagen sources. In this study, collagen has been isolated from the skins of the squids using acid-based and pepsin-based protocols, with the higher yield being obtained from I. argentinus in the presence of pepsin. The produced collagen has been characterized in terms of physicochemical properties, evidencing an amino acid profile similar to the one of calf collagen, but exhibiting a less preserved structure, with hydrolyzed portions and a lower melting temperature. Pepsin-soluble collagen isolated from I. argentinus was selected for further evaluation of biomedical potential, exploring its incorporation on poly-ε-caprolactone (PCL) 3D printed scaffolds for the development of hybrid scaffolds for tissue engineering, exhibiting hierarchical features. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Recovering greater fungal diversity from pristine and diesel fuel contaminated sub-antarctic soil through cultivation using both a high and a low nutrient media approach.

    Science.gov (United States)

    Ferrari, Belinda C; Zhang, Chengdong; van Dorst, Josie

    2011-01-01

    Novel cultivation strategies for bacteria are widespread and well described for recovering greater diversity from the "hitherto" unculturable majority. While similar approaches have not yet been demonstrated for fungi it has been suggested that of the 1.5 million estimated species less than 5% have been recovered into pure culture. Fungi are known to be involved in many degradative processes, including the breakdown of petroleum hydrocarbons, and it has been speculated that in Polar Regions they contribute significantly to bioremediation of contaminated soils. Given the biotechnological potential of fungi there is a need to increase efforts for greater species recovery, particularly from extreme environments such as sub-Antarctic Macquarie Island. In this study, like the yet-to-be cultured bacteria, high concentrations of nutrients selected for predominantly different fungal species to that recovered using a low nutrient media. By combining both media approaches to the cultivation of fungi from contaminated and non-contaminated soils, 91 fungal species were recovered, including 63 unidentified species. A preliminary biodegradation activity assay on a selection of isolates found that a high proportion of novel and described fungal species from a range of soil samples were capable of hydrocarbon degradation and should be characterized further.

  20. The effects of a spillage of diesel fuel on a rocky shore in the sub-Antarctic region (Macquarie Island)

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, R.D.; Smith, S.D.A.; Pople, A.R. [University of New England, Armidale (Australia). Dept. of Zoology

    1995-04-01

    On 3 December 1987, the supply ship Nella Dan ran aground at Macquarie island (54{sup o}29`S. 158{sup o}58`E) releasing about 270 000 1 of oil, mostly light marine diesel, into the sea. At the time of the incident, many marine invertebrates were washed up dead along 2 km of shoreline. Twelve months later, the shore community was investigated using (1) algal and invertebrate populations of the littoral and sublittoral rocky shore, and (2) the invertebrate communities living in the holdfasts of the giant kelp Durvillaea antarctica, which were collected for later examination. Investigations were undertaken at both affected and control locations. Analyses of differences in community structure involved nested ANOVA and multi-dimensional scaling techniques. On the rocky substrate, the effect of the spill was restricted to some biota of the lower littoral and sublittoral zones -particularly echinoderms and the patellid limpet Nacella macquariensis. There were differences in cover for some algal species between locations. Within the kelp holdfasts, communities were dominated by peracarid crustaceans at control locations and by polychaetes (particularly the opportunistic groups - capitellids, cirratulids and spionids) at oil-affected locations. The communities have recently been re-surveyed (in the summer of 1994-95) to assist in the interpretation of the results and to gauge the extent of recovery of the affected biota. (author)

  1. Sub-Antarctic glacier extensions in the Kerguelen region (49°S, Indian Ocean) over the past 24,000 years constrained by 36Cl moraine dating

    Science.gov (United States)

    Jomelli, Vincent; Mokadem, Fatima; Schimmelpfennig, Irene; Chapron, Emmanuel; Rinterknecht, Vincent; Favier, Vincent; Verfaillie, Deborah; Brunstein, Daniel; Legentil, Claude; Michel, Elisabeth; Swingedouw, Didier; Jaouen, Alain; Aumaitre, Georges; Bourlès, Didier L.; Keddadouche, Karim

    2017-04-01

    Similar to many other regions in the world, glaciers in the southern sub-polar regions are currently retreating. In the Kerguelen Islands (49°S, 69°E), the mass balance of the Cook Ice Cap (CIC), the largest ice cap in this region, experienced dramatic shrinking between 1960 and 2013 with retreat rates among the highest in the world. This observation needs to be evaluated in a long-term context. However, data on the past glacier extents are sparse in the sub-Antarctic regions. To investigate the deglaciation pattern since the Last Glacial Maximum (LGM) period, we present the first 13 cosmogenic 36Cl surface exposure ages from four sites in the Kerguelen Islands. The 36Cl ages from erratic and moraine boulders span from 24.4 ± 2.7 ka to 0.3 ± 0.1 ka. We combined these ages with existing glacio-marine radiocarbon ages and bathymetric data to document the temporal and spatial changes of the island's glacial history. Ice began to retreat on the main island before 24.4 ± 2.7 ka until around the time of the Antarctic Cold Reversal (ACR) period (∼14.5-12.9 ka), during which the Bontemps moraine was formed by the advance of a CIC outlet glacier. Deglaciation continued during the Holocene probably until 3 ka with evidence of minor advances during the last millennium. This chronology is in pace with major changes in δ18O in a recent West Antarctica ice core record, showing that Kerguelen Islands glaciers are particularly sensitive and relevant to document climate change in the southern polar regions.

  2. Effects of temperature and fertilization on the structure of total versus active bacterial communities from sub-Antarctic seawater exposed to crude oil and diesel fuel

    Directory of Open Access Journals (Sweden)

    Arturo Rodríguez-Blanco

    2013-05-01

    Full Text Available Polar environments are exposed to the risk of oil pollution. However, there is limited knowledge regarding how the variation of physicochemical factors influencing biodegradation may affect bacterial community structure. The effects of temperature (4, 10 and 20°C and organic fertilization (Inipol EAP 22 on community structure and diversity of bacteria inhabiting Kerguelen sub-Antarctic waters were studied in crude- and diesel-amended microcosms. Dynamics of total (i.e., 16S rDNA-based and metabolically active (i.e., 16S rRNA-based bacterial community structure and diversity were monitored using capillary-electrophoresis single-strand conformation polymorphism. Results showed that total and active community structures were differently influenced by temperature and fertilization in the presence of hydrocarbons. Both fertilization and temperature induced changes in total community structure in the presence of crude oil and diesel. However, temperature showed a limited influence on active community structure, and fertilization induced changes in the presence of crude oil only. Simpson's index decreased for total bacterial communities at all temperatures in the presence of crude oil and diesel, whereas a lower reduction was observed for active bacterial populations. In the presence of fertilizer, the diversity of the whole community approached control values after seven incubation weeks; this was not observed for the active bacterial community. This study evidenced qualitative differences in total and active bacterial community structures of Kerguelen seawaters in the presence of hydrocarbons and different responses relative to variation in temperature and fertilization. These factors and hydrocarbons composition have to be taken into account to understand bacterial community dynamics after an oil spill.

  3. Further notes on the spiders of New Guinea I (Argyopidae)

    NARCIS (Netherlands)

    Chrysanthus, Fr.

    1971-01-01

    In this paper several collections of spiders are dealt with, originating from New Guinea, Bismarck Arch., Solomon Is., and from islands of the Great Barrier Reef and in the Coral Sea. Descriptions, figures and/or remarks are given of the following species: Argyope aemula (Walckenaer), A. aetherea

  4. PATHWAYS TO SPIDER PHOBIA

    NARCIS (Netherlands)

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

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

  5. Catalogue of Texas spiders

    Science.gov (United States)

    Dean, David Allen

    2016-01-01

    Abstract This catalogue lists 1,084 species of spiders (three identified to genus only) in 311 genera from 53 families currently recorded from Texas and is based on the “Bibliography of Texas Spiders” published by Bea Vogel in 1970. The online list of species can be found at http://pecanspiders.tamu.edu/spidersoftexas.htm. Many taxonomic revisions have since been published, particularly in the families Araneidae, Gnaphosidae and Leptonetidae. Many genera in other families have been revised. The Anyphaenidae, Ctenidae, Hahniidae, Nesticidae, Sicariidae and Tetragnathidae were also revised. Several families have been added and others split up. Several genera of Corinnidae were transferred to Phrurolithidae and Trachelidae. Two genera from Miturgidae were transferred to Eutichuridae. Zoridae was synonymized under Miturgidae. A single species formerly in Amaurobiidae is now in the Family Amphinectidae. Some trapdoor spiders in the family Ctenizidae have been transferred to Euctenizidae. Gertsch and Mulaik started a list of Texas spiders in 1940. In a letter from Willis J. Gertsch dated October 20, 1982, he stated “Years ago a first listing of the Texas fauna was published by me based largely on Stanley Mulaik material, but it had to be abandoned because of other tasks.” This paper is a compendium of the spiders of Texas with distribution, habitat, collecting method and other data available from revisions and collections. This includes many records and unpublished data (including data from three unpublished studies). One of these studies included 16,000 adult spiders belonging to 177 species in 29 families. All specimens in that study were measured and results are in the appendix. Hidalgo County has 340 species recorded with Brazos County at 323 and Travis County at 314 species. These reflect the amount of collecting in the area. PMID:27103878

  6. Spider phylogenomics: untangling the Spider Tree of Life

    OpenAIRE

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

    2015-01-01

    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 typical...

  7. A role for oxygen delivery and extracellular magnesium in limiting cold tolerance of the sub-antarctic stone crab Paralomis granulosa?

    Science.gov (United States)

    Wittmann, Astrid C; Pörtner, Hans O; Sartoris, Franz J

    2012-01-01

    A low capacity for regulation of extracellular Mg(2+) has been proposed to exclude reptant marine decapod crustaceans from temperatures below 0°C and thus to exclude them from the high Antarctic. To test this hypothesis and to elaborate the underlying mechanisms in the most cold-tolerant reptant decapod family of the sub-Antarctic, the Lithodidae, thermal tolerance was determined in the crab Paralomis granulosa (Decapoda, Anomura, Lithodidae) using an acute stepwise temperature protocol (-1°, 1°, 4°, 7°, 10°, and 13°C). Arterial and venous oxygen partial pressures (Po(2)) in hemolymph, heartbeat and ventilation beat frequencies, and hemolymph cation composition were measured at rest and after a forced activity (righting) trial. Scopes for heartbeat and ventilation beat frequencies and intermittent heartbeat and scaphognathite beat rates at rest were evaluated. Hemolymph [Mg(2+)] was experimentally reduced from 30 mmol L(-1) to a level naturally observed in Antarctic caridean shrimps (12 mmol L(-1)) to investigate whether the animals remain more active and tolerant to cold (-1°, 1°, and 4°C). In natural seawater, righting speed was significantly slower at -1° and 13°C, compared with acclimation temperature (4°C). Arterial and venous hemolymph Po(2) increased in response to cooling even though heartbeat and ventilation beat frequencies as well as scopes decreased. At rest, ionic composition of the hemolymph was not affected by temperature. Activity induced a significant increase in hemolymph [K(+)] at -1° and 1°C. Reduction of hemolymph [Mg(2+)] did not result in an increase in activity, an increase in heartbeat and ventilation beat frequencies, or a shift in thermal tolerance to lower temperatures. In conclusion, oxygen delivery in this cold-water crustacean was not acutely limiting cold tolerance, and animals may have been constrained more by their functional capacity and motility. In contrast to earlier findings in temperate and subpolar brachyuran

  8. 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.

  9. The seasonal evolution of shelf water masses around Bouvetøya, a sub-Antarctic island in the mid-Atlantic sector of the Southern Ocean, determined from an instrumented southern elephant seal

    Directory of Open Access Journals (Sweden)

    Andrew D. Lowther

    2016-10-01

    Full Text Available Our study makes use of a fortuitous oceanographic data set collected around the remote sub-Antarctic island of Bouvetøya by a conductivity–temperature–depth recorder (CTD integrated with a satellite-relayed data logger deployed on an adult female southern elephant seal (Mirounga leonina to describe the seasonal evolution of the western shelf waters. The instrumented seal remained in waters over the shelf for 259 days, collecting an average of 2.6 (±0.06 CTD profiles per day, providing hydrographic data encompassing the late austral summer and the entire winter. These data document the thermal stratification of the upper water layer due to summer surface heating of the previous year's Antarctic Surface Water, giving way to a cold subsurface layer at about 100 m as the austral winter progressed, with a concomitant increase in salinity of the upper layer. Upper Circumpolar Deep Water was detected at a depth of approximately 200 m along the western shelf of Bouvetøya throughout the year. These oceanographic data represent the only seasonal time series for this region and the second such animal–instrument oceanographic time series in the sub-Antarctic domain of the Southern Ocean.

  10. Extended spider cognition.

    Science.gov (United States)

    Japyassú, Hilton F; Laland, Kevin N

    2017-05-01

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

  11. Animal coloration: sexy spider scales.

    Science.gov (United States)

    Taylor, Lisa A; McGraw, Kevin J

    2007-08-07

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

  12. [History of Polish botanical and mycological researches on sheets of land of Antarctic and Sub-Antarctic in the years 1977-2009].

    Science.gov (United States)

    Köhler, Piotr; Olech, Maria

    2011-01-01

    Antarctic from the late Cretaceous period to the beginning of Melville's continental glaciation. One singled out three floristic stages and were reconstructed their peculiarities in the development of flora. There was also described an early Jurassic flora of Hope Bay (Półwysep Antarktyczny - Antarctic Peninsula) that turned out to be the richest Jurassic flora in the world. From that point of view were analyzed new species of mineral plants. Ecological researches concentrated on the problems connected with several issues and, among others, with the processes of settlement and succession, distribution and ecology of land biotopes, changes in their spatial structure, and state of biotopes' biological mass. The second group of issues concerned the anthropogenous impacts. One also analyzed early stages of synanthropization of flora. Another important issue was recognizing an extent of the pollution of the environment, particularly with base metals. In the years 1977-2009 were published, at least, 426 notes, articles and monographs that were a result of botanical and mycological researches on sheets of land of Antarctic and Sub-Antarctic.

  13. Black widow spider and brown recluse spider bites in Texas from 1998 through 2002.

    Science.gov (United States)

    Forrester, Mathias B; Stanley, Sharilyn K

    2003-10-01

    Black widow spiders and brown recluse spiders are of medical importance to humans in the US. However, these spiders differ in their habits, habitat, and the clinical effects and treatment of their bite. This study used data from human exposure calls to poison centers in Texas to compare the epidemioloy of bites from these 2 spiders. During 1998-2002, 760 black widow spider bites and 1,369 brown recluse spider bites were reported. Black widow spider bite penetrance demonstrated no secular trend during this time period while the penetrance of brown recluse spider bites increased. A higher percentage of black widow spider bites occurred among males, while a higher proportion of brown recluse spider bites were reported for females. Black widow spider bites most frequently had mild outcomes while brown recluse spider bites most often had moderate outcomes. The majority of reported bites for both types of spider occurred at the patient's own residence, although the percentage was lower for black widow spiders. Seasonal trends were noted for both black widow and brown recluse spiders. The highest penetrance of black widow spider bites was observed in western Texas while the highest penetrance of brown recluse spider bites was observed in central Texas. This information is useful for identifying those populations at greatest risk for the respective spider bites.

  14. Cell culture's spider silk road.

    Science.gov (United States)

    Perkel, Jeffrey

    2014-06-01

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

  15. Funnel-web spider bite

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002844.htm Funnel-web spider bite To use the sharing features on ... Duplication for commercial use must be authorized in writing by ADAM Health Solutions. About MedlinePlus Site Map ...

  16. The sejugal furrow in camel spiders and acariform mites

    Directory of Open Access Journals (Sweden)

    Dunlop, Jason A.

    2012-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Jiang Min

    2016-01-01

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

  18. 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

  19. Spider phylogenomics: untangling the Spider Tree of Life

    Directory of Open Access Journals (Sweden)

    Nicole L. Garrison

    2016-02-01

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

  20. Brown recluse spider bites: a case report.

    Science.gov (United States)

    Nunnelee, Janice D

    2006-02-01

    The brown recluse spider is found more commonly in the Southeast and the Central Midwest. Its bite is not common because it is a shy spider that only bites if cornered. A severe bite may necrose a large area that requires skin grafting; systemic reactions rarely occur. This article discusses the brown recluse spider and presents a case study of a patient with two spider bites that did require extensive grafting.

  1. Brown recluse spider bite on the breast.

    Science.gov (United States)

    Norris, Kori; Misra, Subhasis

    2014-05-01

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

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

    Science.gov (United States)

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

    2013-03-01

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

  3. Reports of envenomation by brown recluse spiders (Araneae: Sicariidae) outnumber verifications of Loxosceles spiders in Florida.

    Science.gov (United States)

    Vetter, Richard S; Edwards, G B; James, Louis F

    2004-07-01

    Bites attributed to the brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, are frequently reported by medical personnel throughout Florida, whereas the extensive arachnological evidence contradicts the alleged widespread occurrence of Loxosceles spiders in the state. We compared reports of brown recluse spider bites made by medical personnel from a 6-yr Florida poison control center database to the known verifications of Loxosceles spiders from 100 yr of Florida arachnological data. Medical personnel diagnosed 124 brown recluse spider bites from 31 of Florida's 67 counties in 6 yr. In contrast, only 11 finds of approximately 70 Loxosceles spiders have been made in 10 Florida counties in 100 yr. Florida does not have sufficient widespread populations of Loxosceles spiders to warrant consideration of brown recluse spider envenomation as a probable etiology of dermonecrosis. Florida health care would improve if medical personnel would consider the multitude of other etiologies that manifest in dermonecrosis.

  4. The Legs That Rock the Cradle: Spider Mothers

    Indian Academy of Sciences (India)

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

  5. Epidemiology of the brown recluse spider bite.

    Science.gov (United States)

    Rhoads, Jacqueline

    2007-02-01

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

  6. Spatial subsidies in spider diets vary with shoreline structure: Complementary evidence from molecular diet analysis and stable isotopes.

    Science.gov (United States)

    Hambäck, Peter A; Weingartner, Elisabeth; Dalén, Love; Wirta, Helena; Roslin, Tomas

    2016-12-01

    Inflow of matter and organisms may strongly affect the local density and diversity of organisms. This effect is particularly evident on shores where organisms with aquatic larval stages enter the terrestrial food web. The identities of such trophic links are not easily estimated as spiders, a dominant group of shoreline predator, have external digestion. We compared trophic links and the prey diversity of spiders on different shore types along the Baltic Sea: on open shores and on shores with a reed belt bordering the water. A priori, we hypothesized that the physical structure of the shoreline reduces the flow between ecosystem and the subsidies across the sea-land interface. To circumvent the lack of morphologically detectable remains of spider prey, we used a combination of stable isotope and molecular gut content analyses. The two tools used for diet analysis revealed complementary information on spider diets. The stable isotope analysis indicated that spiders on open shores had a marine signal of carbon isotopes, while spiders on reedy shores had a terrestrial signal. The molecular analysis revealed a diverse array of dipteran and lepidopteran prey, where spiders on open and reedy shores shared a similar diet with a comparable proportion of chironomids, the larvae of which live in the marine system. Comparing the methods suggests that differences in isotope composition of the two spider groups occurred because of differences in the chironomid diets: as larvae, chironomids of reedy shores likely fed on terrestrial detritus and acquired a terrestrial isotope signature, while chironomids of open shores utilized an algal diet and acquired a marine isotope signature. Our results illustrate how different methods of diet reconstruction may shed light on complementary aspects of nutrient transfer. Overall, they reveal that reed belts can reduce connectivity between habitats, but also function as a source of food for predators.

  7. Reports of envenomation by brown recluse spiders exceed verified specimens of Loxosceles spiders in South Carolina.

    Science.gov (United States)

    Frithsen, Ivar L; Vetter, Richard S; Stocks, Ian C

    2007-01-01

    To determine whether the number of brown recluse spider bites diagnosed by South Carolina physicians coincides with evidence of brown recluse spiders found in the state. Brown recluse spider bite diagnosis data were extracted from 1990 and 2004 surveys of South Carolina physicians. This was compared with the known historical evidence of brown recluse spiders collected in South Carolina and derived from various sources, including state agencies, arachnologists, and museum specimens. South Carolina physicians diagnosed 478 brown recluse spider bites in 1990 and 738 in 2004. Dating to 1953, 44 brown recluse spider specimens have been verified from 6 locations in South Carolina. The number of brown recluse bites reportedly diagnosed in South Carolina greatly outnumbers the verified brown recluse specimens that have been collected in the state. The pattern of bite diagnoses outnumbering verified brown recluse specimens has been reported in other areas outside of this spider's known endemic range.

  8. Biomechanical characterization of spider webs.

    Science.gov (United States)

    Das, Rakesh; Kumar, Amit; Patel, Anurag; Vijay, Sahil; Saurabh, Shashank; Kumar, Navin

    2017-03-01

    In light of recent focus on the behaviour of the natural structures for revolutionary technological growth, spider web seems to have seized considerable attention of product designer due to its amazing behaviour. In present work, mechanism behind the structural integrity of the spider web along with the materialistic analysis of its constituent silk threads has been extensively investigated. The nanoindentation tool both in static and dynamic mode has been utilized for complete analysis of the mechanical behaviour of the spiral and radial threads separately. Both the average elastic modulus and hardness of the radial silk thread is higher than the spiral silk thread which reveals the radial silk thread is the major structural component of the web. The sustainability of spider webs under storm, windy conditions and during the impact of pray has been investigated under dynamic conditions. The radial silk thread exhibits elastic like response and the spiral silk thread exhibits viscous like response in a wide frequency range (1-200Hz). The damping characteristic of the radial and spiral silk threads, an important parameter to investigate the energy dissipation properties of the materials has also been investigated in windy conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. (Araneae: Palpimanidae) on jumping spiders (Araneae: Salticidae)

    African Journals Online (AJOL)

    This is the first detailed report on the natural prey and the prey-capture tactics of a Palpimanus sp. from Entebbe (Uganda). Although this species fed occasionally on insects, its dominant prey in the field was other spiders, especially jumping spiders (Salticidae) and their eggs. Encounters between Palpimanus sp. and ...

  10. Hey! A Black Widow Spider Bit Me!

    Science.gov (United States)

    ... System Taking Care of Your Teeth Bad Breath Hey! A Black Widow Spider Bit Me! KidsHealth > For Kids > Hey! A Black Widow Spider Bit Me! Print A ... For Kids For Parents MORE ON THIS TOPIC Hey! A Tarantula Bit Me! Hey! A Flea Bit ...

  11. Hey! A Brown Recluse Spider Bit Me!

    Science.gov (United States)

    ... System Taking Care of Your Teeth Bad Breath Hey! A Brown Recluse Spider Bit Me! KidsHealth > For Kids > Hey! A Brown Recluse Spider Bit Me! Print A ... For Kids For Parents MORE ON THIS TOPIC Hey! A Fire Ant Stung Me! Hey! A Tarantula ...

  12. 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 ...

  13. The ecological consequences of temperament in spiders

    Directory of Open Access Journals (Sweden)

    Jonathan N. PRUITT, Susan E. RIECHERT

    2012-08-01

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

  14. Identifying and misidentifying the brown recluse spider.

    Science.gov (United States)

    Vetter, R

    1999-11-01

    The brown recluse spider, Loxosceles reclusa, is often implicated as a cause of necrotic skin lesions.[1-3] Diagnoses are most commonly made by clinical appearance and infrequently is a spider seen, captured or identified at the time of the bite.[1, 2, 4-6] The brown recluse lives in a circumscribed area of the U.S. (the south central Midwest) with a few less common recluse species living in the more sparsely-populated southwest U.S.[7] In these areas, where spider populations may be dense, recluse spiders may be a cause of significant morbidity. However, outside the natural range of these recluse species, the conviction that they are the etiological agents behind necrotic lesions of unknown origin is widespread, and most often erroneous. In some states such as California, unsubstantiated reports concerning recluse spider bites have taken on the status of "urban legend" leading to overdiagnosis and, therefore, inappropriate treatment.

  15. Differential accumulation of heavy metals by web spiders and ground spiders in an old-field

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, K.J.; Brewer, S.R.; Taylor, D.H. (Miami Univ., Oxford, OH (United States). Dept. of Zoology)

    1994-03-01

    Accumulation of the heavy metals Cd, Cu, Pb, and Zn by web spiders (orb weavers: Araneidae) and ground spiders was examined in an old-field that had been subjected to 11 years of nutrient enrichment. The study area consistent of six 0.1-ha plots treated from 1978 to 1988 with municipal sewage sludge containing heavy-metal contaminants, urea-phosphate fertilizer, or left as untreated controls. In 1991 and 1992, heavy-metal concentrations in the soil, ground spiders, and web spiders were measured with a flame AA spectrophotometer. Spiders accumulated Cd, Cu, and Zn to concentrations greater than those present in the soil but did not accumulate Pb. Ground spiders contained significantly higher levels of Cd and Cu than web spiders, whereas web spiders contained slightly greater levels of Pb than ground spiders. No trend between spider guilds was apparent for Zn accumulation. To understand the impact of the application of metal-contaminated municipal sludge on ecosystem, the toxicological effects on the biology and behavior of major biotic components in terrestrial food webs must be known.

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

    Directory of Open Access Journals (Sweden)

    Partchev Ivailo

    2007-11-01

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

  17. Learned predation risk management by spider mites

    Directory of Open Access Journals (Sweden)

    Thomas eHackl

    2014-09-01

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

  18. Lichens of sub-Antarctic Heard Island

    NARCIS (Netherlands)

    Øvstedal, D.O.; Gremmen, N.J.M.

    2006-01-01

    A tota1 of 71 lichen species in 42 genera are listed for the island. Three species are described as new: “Arctomia” latispora Øvstedal, Fellhaneropsis subantarctica Øvstedal and Stereocaulon heardii Øvstedal. More than half of the species are restricted to the southern cold zone (Antarctica and

  19. Brown recluse spider bite to the eyelid.

    Science.gov (United States)

    Jarvis, R M; Neufeld, M V; Westfall, C T

    2000-08-01

    To present a photographically documented case of a known brown recluse spider bite to the eyelid. Interventional case report. The wound was photographed daily during an 11-day hospitalization and at 1 month and 6 months after the injury. Treatment included canthotomy and cantholysis; administration of dapsone, antibiotics, and steroids; and hyperbaric oxygen therapy. Clinical presentation and course of a known brown recluse spider bite. Complete recovery with cicatrization at the site of the bite. We present a case of a brown recluse spider bite to the left lower eyelid with a discussion of management and outcome of this rarely reported injury.

  20. SPIDERS (ARANEI OF NORTH CASPIAN COAST AND ISLANDS

    Directory of Open Access Journals (Sweden)

    A. V. Ponomare

    2014-01-01

    Full Text Available Abstract. Aim. Araneofauna of Peri-Caspian is fragmentary studied. A literature contains faunistic data for the North-West Caspian and Volga River delta. Several faunistic records and new species were earlier described from the North Caspian. Spiders of Mangyshlak are insufficiently studied. The aim of this wark is summation of available data on araneofauna of coast and islands of North Peri-Caspian with more detailed analisys of spiders of North Caspian islands. Location. Russia: Astrakhan Region, Dagestan, Kalmykia; Kazakhstan: Atyrau and Mangystau Regions.Methods. Investigations include Caspian coastal zone with width about 20 km from Makhachkala (western coast to Tyub Kurgan (eastern coast and islands of the Caspian Sea: Nordovyi, Tyuleniy, Chechen, Kulaly. Pitfall traps and manual collection were used during 1975–1985 and 2009–2013.Results and main conclusions. Annotated check-list of 325 species of spiders from 31 families is made for North Caspian coast and islands. Species of the families Gnaphosidae (67 species, Salticidae (46 species и Lycosidae (37 species are dominated. Three hundred four species are known from coastal (width 20 km zone (from Makhachkala to Tyub Kurgan and 132 species were found on islands. North-Eastern Peri-Caspian coast contents 198 species, Volga River delta – 134 species, coast of North and North Eastern Caspian – 98 species. Number of species on Caspian islands: Nordovyi – 30, Tuleniy – 83, Chechen – 66, Kulaly – 43. Each island has its special araneofauna. There are significant differences in fauna composition of different parts of coastal zone.

  1. An approach to spider bites. Erroneous attribution of dermonecrotic lesions to brown recluse or hobo spider bites in Canada.

    Science.gov (United States)

    Bennett, Robert G; Vetter, Richard S

    2004-08-01

    To dispel prevalent myths surrounding diagnosis of dermonecrotic and associated conditions supposedly resulting from bites of brown recluse, hobo, or other spiders in Canada. Worldwide, spider bites are regularly misdiagnosed as the etiologic agents in human dermonecrosis mainly as a result of inaccurate, erroneous, or hyperbolic popular and professional literature based on inference, circumstantial evidence, inferior clinical trials, and misunderstanding of the facts regarding spider-bite envenomation. A working diagnosis of "spider bite" or publishing a case history should be considered only when a spider is caught in the act of biting or otherwise reliably associated with a lesion. Accurate identification of the spider could be critical for correct diagnosis and subsequent treatment. Brown recluse spiders are not found in Canada. Hobo spiders have not been reliably implicated in dermonecrosis. Worldwide, spider-bite envenomation is an unlikely cause of dermonecrosis. Canadian physicians should give priority consideration to other, more likely, causes.

  2. 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

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

    Science.gov (United States)

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

    2016-03-30

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

  4. 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.

  5. 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.

  6. Summary statistics for fossil spider species taxonomy

    Directory of Open Access Journals (Sweden)

    David Penney

    2012-05-01

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

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

    NARCIS (Netherlands)

    Kindt, M.; Brosschot, J.F.

    1999-01-01

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

  8. 46 SPIDER WEBS AS INDICATORS OF COBALT AND LEAD ...

    African Journals Online (AJOL)

    SPIDER WEBS AS INDICATORS OF COBALT AND LEAD POLLUTION IN KANO. MUNICIPALITY. Ibrahim R.Yalwa. Department ... Keywords: spider, indicator, cobalt, lead, pollution, Kano. INTRODUCTION. Cobalt is required for ..... Agency for Toxic Substances and Disease Registry. (ATSDR), (1992). Toxicological Profile.

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

    Science.gov (United States)

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

    2015-09-01

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

  10. Mass predicts web asymmetry in Nephila spiders

    Science.gov (United States)

    Kuntner, Matjaž; Gregorič, Matjaž; Li, Daiqin

    2010-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Michael Makris

    2009-01-01

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

  12. 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.

  13. Remembering the Object You Fear: Brain Potentials during Recognition of Spiders in Spider-Fearful Individuals

    Science.gov (United States)

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

    2014-01-01

    In the present study we investigated long-term memory for unpleasant, neutral and spider pictures in 15 spider-fearful and 15 non-fearful control individuals using behavioral and electrophysiological measures. During the initial (incidental) encoding, pictures were passively viewed in three separate blocks and were subsequently rated for valence and arousal. A recognition memory task was performed one week later in which old and new unpleasant, neutral and spider pictures were presented. Replicating previous results, we found enhanced memory performance and higher confidence ratings for unpleasant when compared to neutral materials in both animal fearful individuals and controls. When compared to controls high animal fearful individuals also showed a tendency towards better memory accuracy and significantly higher confidence during recognition of spider pictures, suggesting that memory of objects prompting specific fear is also facilitated in fearful individuals. In line, spider-fearful but not control participants responded with larger ERP positivity for correctly recognized old when compared to correctly rejected new spider pictures, thus showing the same effects in the neural signature of emotional memory for feared objects that were already discovered for other emotional materials. The increased fear memory for phobic materials observed in the present study in spider-fearful individuals might result in an enhanced fear response and reinforce negative beliefs aggravating anxiety symptomatology and hindering recovery. PMID:25296032

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

    Science.gov (United States)

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

    2014-01-01

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

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Martin Nyffeler

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

  17. Spider Invasion Across the Galaxy

    Directory of Open Access Journals (Sweden)

    Chung-Yue Hui

    2014-06-01

    Full Text Available 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.

  18. Spider web-inspired acoustic metamaterials

    Science.gov (United States)

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

    2016-08-01

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

  19. The evolution of sociality in spiders

    DEFF Research Database (Denmark)

    Lubin, Yael; Bilde, T.

    2007-01-01

    -Biased Colony Sex Ratios: Primary and Operational Sex Ratios E. Mating System: Inbreeding and Its Population-Genetic Consequences F. "Boom and Bust" Colony Dynamics IV. Phylogenetic Relationships Among Social Spider Species A. Common Features of Social Evolution B. Case Studies 1. Stegodyphus (Eresidae) 2....... Anelosimus (Theridiidae) C. Sociality in Spiders: An Evolutionary Dead End? V. Evolution and Maintenance of Sociality in Spiders: Relevant Models A. Kin Selection 1. Kin Recognition 2. Inbreeding and Kin Selection B. Multilevel Selection (Group Selection) C. Ecological Benefits D. Ecological Constraints E....... 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...

  20. Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-15

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

  1. 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.

  2. 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

  3. 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

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

    Science.gov (United States)

    Vetter, Richard S

    2011-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Breitling, Rainer

    2015-11-01

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

  6. Spider Silk Spun and Integrated into Composites

    Science.gov (United States)

    2009-02-20

    biomimetic analogues. Biological functionality, after all, relies on wet engineering. OUTLOOK.: There are many other natural hybrid nano-composites. In...explains the large interspecific variability of spider dragline silks observed by us and other groups. Moreover, MAA silks from three representative

  7. The aerodynamic signature of running spiders.

    Directory of Open Access Journals (Sweden)

    Jérôme Casas

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

  8. Spiders Tune Glue Viscosity to Maximize Adhesion.

    Science.gov (United States)

    Amarpuri, Gaurav; Zhang, Ci; Diaz, Candido; Opell, Brent D; Blackledge, Todd A; Dhinojwala, Ali

    2015-11-24

    Adhesion in humid conditions is a fundamental challenge to both natural and synthetic adhesives. Yet, glue from most spider species becomes stickier as humidity increases. We find the adhesion of spider glue, from five diverse spider species, maximizes at very different humidities that matches their foraging habitats. By using high-speed imaging and spreading power law, we find that the glue viscosity varies over 5 orders of magnitude with humidity for each species, yet the viscosity at maximal adhesion for each species is nearly identical, 10(5)-10(6) cP. Many natural systems take advantage of viscosity to improve functional response, but spider glue's humidity responsiveness is a novel adaptation that makes the glue stickiest in each species' preferred habitat. This tuning is achieved by a combination of proteins and hygroscopic organic salts that determines water uptake in the glue. We therefore anticipate that manipulation of polymer-salts interaction to control viscosity can provide a simple mechanism to design humidity responsive smart adhesives.

  9. Status of the CNESM diagnostic for SPIDER

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

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

    Directory of Open Access Journals (Sweden)

    Yunhua Zhong

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

  11. The canopy spiders (Araneae of the floodplain forest in Leipzig

    Directory of Open Access Journals (Sweden)

    Otto, Stefan

    2010-10-01

    Full Text Available The canopy spiders of the floodplain forest in Leipzig have become a focus of ecological studies in recent years. In 2006 we sampled 30 tree canopies in the ‘Burgaue’ nature reserve with pyrethrum knock-down fogging, recording 502 adult spiders belonging to 48 species and 11 families. Based on these data and the results of a previous fogging study, the studied spider community was dominated by forest and forest-edge species with a preference for the shrub and canopy strata as well as by spiders of the web spider feeding guild. The community structure was typical for arboreal spider communities from northern temperate forests but very different from communities in the tropics. Species richness and evenness were similar to the old growth near-primary Białowieża Forest in Poland. The checklist of 96 canopy spider species of the floodplain forest of Leipzig includes 54 additions to the spider fauna of Leipzig and vicinity by recent canopy studies and eight first canopy records for Leipzig from our field work. The theridiid Dipoena torva (Thorell, 1875 was recorded for the first time in Saxony. The floodplain forest of Leipzig sustains a large and species-rich arboreal spider community and is thus a valuable habitat for a large proportion of endangered species (12%.

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

    Science.gov (United States)

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

    2012-01-01

    Spider webs are made of silk, the properties of which ensure remarkable efficiency at capturing prey. However, remaining on, or near, the web exposes the resident spiders to many potential predators, such as ants. Surprisingly, ants are rarely reported foraging on the webs of orb-weaving spiders, despite the formidable capacity of ants to subdue prey and repel enemies, the diversity and abundance of orb-web spiders, and the nutritional value of the web and resident spider. We explain this paradox by reporting a novel property of the silk produced by the orb-web spider Nephila antipodiana (Walckenaer). These spiders deposit on the silk a pyrrolidine alkaloid (2-pyrrolidinone) that provides protection from ant invasion. Furthermore, the ontogenetic change in the production of 2-pyrrolidinone suggests that this compound represents an adaptive response to the threat of natural enemies, rather than a simple by-product of silk synthesis: while 2-pyrrolidinone occurs on the silk threads produced by adult and large juvenile spiders, it is absent on threads produced by small juvenile spiders, whose threads are sufficiently thin to be inaccessible to ants. PMID:22113027

  13. Spider mites of Japan: their biology and control.

    Science.gov (United States)

    Takafuji, A; Ozawa, A; Nemoto, H; Gotoh, T

    2000-01-01

    Spider mite biology and control in Japan were reviewed. Seventy-eight spider mite species of 16 genera (Family Tetranychidae) have been recorded in Japan. Several of the species recently described were separated from a species complex comprising strains with different ecological performance such as host range. These separations were first supported by crossing experiments and then confirmed by molecular genetic studies. Spider mite control in Japan is still dependent on heavy acaricide spraying in order to attain products of extremely high quality. The commercial use of natural enemies in spider mite management has just started.

  14. Araneae Sloveniae: a national spider species checklist

    Science.gov (United States)

    Kostanjšek, Rok; Kuntner, Matjaž

    2015-01-01

    Abstract The research of the spider fauna of Slovenia dates back to the very beginning of binomial nomenclature, and has gone through more and less prolific phases with authors concentrating on taxonomy, faunistics, ecology and zoogeographic reviews. Although the body of published works is remarkable for a small nation, the faunistic data has remained too scattered for a thorough understanding of regional biotic diversity, for comparative and ecological research, and for informed conservation purposes. A national checklist is long overdue. Here, a critical review of all published records in any language is provided. The species list currently comprises 738 species, is published online at http://www.bioportal.si/katalog/araneae.php under the title Araneae Sloveniae, and will be updated in due course. This tool will fill the void in cataloguing regional spider faunas and will facilitate further araneological research in central and southern Europe. PMID:25632258

  15. Araneae Sloveniae: a national spider species checklist

    Directory of Open Access Journals (Sweden)

    Rok Kostanjšek

    2015-01-01

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

  16. The Jean Gutierrez spider mite collection

    Directory of Open Access Journals (Sweden)

    Alain Migeon

    2015-03-01

    Full Text Available The family Tetranychidae (spider mites currently comprises 1,275 species and represents one of the most important agricultural pest families among the Acari with approximately one hundred pest species, ten of which considered major pests. The dataset presented in this document includes all the identified spider mites composing the Jean Gutierrez Collection hosted at the CBGP (Montferrier-sur-Lez, France, gathered from 1963 to 1999 during his career at the Institut de Recherche pour le Développement (IRD. It consists of 5,262 specimens corresponding to 1,564 occurrences (combination species/host plant/date/location of 175 species. Most specimens were collected in Madagascar and other islands of the Western Indian Ocean, New Caledonia and other islands of the South Pacific and Papuasia. The dataset constitutes today the most important one available on Tetranychidae worldwide.

  17. Histological findings after brown recluse spider envenomation.

    Science.gov (United States)

    Elston, D M; Eggers, J S; Schmidt, W E; Storrow, A B; Doe, R H; McGlasson, D; Fischer, J R

    2000-06-01

    Histologic specimens from 41 rabbits were studied for changes resulting from the manual injection of brown recluse spider venom. Major findings included a mixed inflammatory cell infiltrate, coagulative tissue necrosis, and vasculitis. All specimens demonstrated a well-delineated zone of eosinophilic staining recognizable as "mummified" coagulative necrosis of the epidermis and dermis. A dense band of neutrophils bordered the zone of necrosis. Immediately adjacent to the neutrophilic band, small vessel vasculitis was a universal finding. Degranulated eosinophils and neutrophils and macrophages filled with eosinophilic granules were common. Inflammatory foci were often centered on groups of lipocytes within the dermis. Large vessel vasculitis resembling that seen in polyarteritis nodosa was present deep to 7 of the 40 eschars. Large vessel vasculitis may contribute to the large zones of necrosis seen after some brown recluse spider bites. Eosinophils may play a role in tissue damage after envenomation.

  18. 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

    for unrelated sperm via pre- and/or post-copulatory mechanisms could restore female fitness when inbreeding depression increases. Using inbred isofemale lines we provided female spiders with one or two male spiders of different relatedness in five combinations: one male sib; one male nonsib; two male sibs; two......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...

  19. Designing Spider Silk Proteins for Materials Applications

    Science.gov (United States)

    2009-10-28

    acid (X) in the [GPGGX]2 elastic motif and temperature have an impact on the amount of β-sheet structures present in the proteins. More specifically...increasing temperatures seem to be positively correlated with β-sheet formation for both proteins and this state is irreversible or reversible when...Cheryl Y. Hayashi Expansion and Intragenic Homogenization of Spider Silk Genes since the Triassic : Evidence from Mygalomorphae (Tarantulas and Their

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

    Directory of Open Access Journals (Sweden)

    Thiago Gonçalves-Souza

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

  1. Host selection by a kleptobiotic spider

    Science.gov (United States)

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

    2005-02-01

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

  2. Nanofibre production in spiders without electric charge.

    Science.gov (United States)

    Joel, Anna-Christin; Baumgartner, Werner

    2017-06-15

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

  3. [Local dermonecrotic loxoscelism in children bitten by the spider Loxosceles reclusa (the "violin" spider)].

    Science.gov (United States)

    Escalante-Galindo, P; Montoya-Cabrera, M A; Terroba-Larios, V M; Nava-Juárez, A R; Escalante-Flores, I

    1999-01-01

    This is an observational retrospective study. Our goal is to describe the local dermonecrotic reaction occurring after a spider bite in eleven pediatric patients. In seven (63.7%), the spider was identified as Loxosceles reclusa, and in four, bites were presumptive. The main symptoms and signs were pain, erythema, swelling, blisters, and vasculitis in five patients. There was a significant relationship between the time of onset before the treatment and the severity of the lesions (63.4 hours in the severe cases vs 14.4 hours in the mild cases, p loxoscelism occurred in this patient.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  6. Alleviation of oxidative stress induced by spider mite invasion ...

    African Journals Online (AJOL)

    Spider mite invasion induces oxidative stress on bean plants and increased soluble sugars, phenole, proline and peroxidase activity, but decreased catalase activity and ascorbic acid and carotenoid concentration. Application of elicitors significantly enhanced spider mite tolerance by decreasing hydrogen peroxide, ...

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

    African Journals Online (AJOL)

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

  8. Task-irrelevant spider associations affect categorization performance

    NARCIS (Netherlands)

    Woud, M.L.; Ellwart, T.; Langner, O.; Rinck, M.; Becker, E.S.

    2011-01-01

    In two studies, the Single Target Implicit Association Test (STIAT) was used to investigate automatic associations toward spiders. In both experiments, we measured the strength of associations between pictures of spiders and either threat-related words or pleasant words. Unlike previous studies, we

  9. 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.

  10. Lyme disease masquerading as brown recluse spider bite.

    Science.gov (United States)

    Osterhoudt, Kevin C; Zaoutis, Theoklis; Zorc, Joseph J

    2002-05-01

    We report a case of Lyme disease with clinical features resembling those described from brown recluse spider bites. The most striking manifestation was a necrotic skin wound. Brown recluse spider bites may be overdiagnosed in some geographic regions. Tick bite and infection with Borrelia burgdorferi should be considered in the differential diagnosis of necrotic arachnidism in regions endemic for Lyme disease.

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

    Directory of Open Access Journals (Sweden)

    Ora C. McWilliams

    2013-06-01

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

  12. Spider bite in southern Africa: diagnosis and management

    African Journals Online (AJOL)

    She is a staff member of the Tygerberg Poison Information Centre and the Therapeutic Drug Monitoring Laboratory,. Division of Pharmacology ..... The spider antivenom is a refined equine anti-spider serum globulin, supplied in 5 ml ampoules. .... Other reported therapies include hyperbaric oxygen, antihistamines (including ...

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

    Directory of Open Access Journals (Sweden)

    C. K. Adarsh

    2015-12-01

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

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

    DEFF Research Database (Denmark)

    Jensen, Kim; Mayntz, David; Toft, Søren

    2011-01-01

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

  15. Biotechnological Trends in Spider and Scorpion Antivenom Development

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Solà, Mireia; Jappe, Emma Christine

    2016-01-01

    Spiders and scorpions are notorious for their fearful dispositions and their ability to inject venom into prey and predators, causing symptoms such as necrosis, paralysis, and excruciating pain. Information on venom composition and the toxins present in these species is growing due to an interest...... in using bioactive toxins from spiders and scorpions for drug discovery purposes and for solving crystal structures of membrane-embedded receptors. Additionally, the identification and isolation of a myriad of spider and scorpion toxins has allowed research within next generation antivenoms to progress...... at an increasingly faster pace. In this review, the current knowledge of spider and scorpion venoms is presented, followed by a discussion of all published biotechnological efforts within development of spider and scorpion antitoxins based on small molecules, antibodies and fragments thereof, and next generation...

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

    DEFF Research Database (Denmark)

    Nørgaard, Thomas; Nilsson, Dan-Eric; Henschel, Joh R

    2008-01-01

    At night the Namib Desert spider Leucorchestris arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders' eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role...... in the 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 combined have...... resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L...

  17. SPIDER: CMB Polarimetry from the Edge of Space

    Energy Technology Data Exchange (ETDEWEB)

    Gualtieri, R.; et al.

    2017-11-28

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

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  19. Morphological evolution of spiders predicted by pendulum mechanics.

    Directory of Open Access Journals (Sweden)

    Jordi Moya-Laraño

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

  20. Dominant covarying climate signals in the Southern Ocean and Antarctic Sea Ice influence during last three decades

    Science.gov (United States)

    Cerrone, Dario; Fusco, Giannetta; Simmonds, Ian; Aulicino, Giuseppe; Budillon, Giorgio

    2017-04-01

    A composite dataset (comprising geopotential height, sea surface temperature, zonal and meridional surface winds, precipitation, cloud cover, surface air temperature, latent plus sensible heat fluxes , and sea ice concentration) has been investigated with the aim of revealing the dominant timescales of variability from 1982 to 2013. Three covarying climate signals associated with variations in the sea ice distribution around Antarctica have been detected through the application of the Multiple-Taper Method with Singular Value Decomposition (MTM-SVD). Features of the established patterns of variation over the Southern Hemisphere (SH) extratropics have been identified in each of these three climate signals in the form of coupled or individual oscillations. The climate patterns considered here are the Southern Annular Mode (SAM), the Pacific-South America (PSA) teleconnection, the Semi-Annual Oscillation (SAO) and Zonal Wavenumber-3 (ZW3) mode. It is shown that most of the sea ice temporal variance is concentrated at the quasi-triennial scale resulting from the constructive superposition of the PSA and ZW3 patterns. In addition the combination of the SAM and SAO patterns is found to promote the interannual sea ice variations underlying a general change in the Southern Ocean atmospheric and oceanic circulations. These two modes of variability are also found consistent with the occurrence of the SAM+/PSA- or SAM-/PSA+ combinations, which could have favored the cooling of the sub-Antarctic and important changes in the Antarctic sea ice distribution since 2000.

  1. Checklist of the spiders (Araneae) of Israel.

    Science.gov (United States)

    Zonstein, Sergei; Marusik, Yuri M

    2013-01-01

    This checklist records 631 spider species and subspecies belonging to 49 families in Israel. Species distributions are given in both generalised (by main geographic areas of the country) and detailed (by localities) form. Twenty-seven records are considered as doubtful and another ten are based on misidentifications. A historical survey is provided. Each record is presented in its original combination. The list is dominated by members of the families Gnaphosidae and Salticidae (20.0% and 17.1% of total species, respectively). The level of regional endemism exceeds 37.0%.

  2. Natural Compounds as Spider Repellents: Fact or Myth?

    Science.gov (United States)

    Fischer, Andreas; Ayasse, Manfred; Andrade, Maydianne C B

    2018-02-09

    Although some spiders are globally invasive, found at high densities, and may be considered pests (particularly those that are toxic to humans), there are few pest management methods based on experimental data. 'Common wisdom' and advertisements on internet websites assert that a number of natural substances repel spiders. We tested whether the three substances cited most frequently (lemon oil, peppermint oil, and chestnut-fruits) effectively repelled female spiders or whether these were myths. We presented each of the putative repellents versus a control in a two-choice assay and tested responses of females of three invasive spider species in two different families: theridiids, Latrodectus geometricus C. L. Koch (Araneae: Theridiidae) and Steatoda grossa C. L. Koch (Araneae: Theridiidae) and the araneid, Araneus diadematus Clerck . Chestnuts (Araneae: Araneidae) and mint oil strongly repelled L. geometricus and A. diadematus. S. grossa was less sensitive to these chemicals but had a slight tendency to avoid chestnuts. However, lemon oil, the substance most likely to be cited as a repellent (over 1,000,000 hits on Google), had no effect on any of these spiders. We conclude that volatiles released by mint oil and chestnuts may be effective in deterring spider settlement in two different families of spiders, but lemon oil as a repellent is a myth. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Acute generalized exanthematous pustulosis (AGEP) triggered by a spider bite.

    Science.gov (United States)

    Makris, Michael; Spanoudaki, Nektaria; Giannoula, Fani; Chliva, Caterina; Antoniadou, Anastasia; Kalogeromitros, Dimitrios

    2009-06-01

    Acute generalized exanthematous pustulosis (AGEP) is a rare and severe cutaneous reaction usually triggered by drugs. Other causative factors such as viral infections are rarely involved. In this study, we report a case of AGEP caused by a spider bite. A 56-year-old woman was referred to the allergy unit after a spider bite at the left popliteal fossa, while gardening, 5 days earlier. The offending spider was captured and identified by an entomologist as belonging to the Loxosceles rufescens species. No acute reaction was observed; however, after 24 hours, due to the occurrence of typical dermonecrotic skin lesions associated with erythema and edema, Cefuroxime and Clindamycin were administered intramuscularly after medical advice was given. Almost 72 hours after the spider bite, an erythematous and partly edematous eruption appeared locally in the gluteus area bilaterally, which progressively expanded to the trunk, arms and femors. Within 24 hours dozens of small, pinhead sized, non-follicular pustules were present, mainly in the folds. The patient complained of a burning sensation of the skin in addition to pruritus; and simultaneously had a fever of 38-39 degrees C as the eruption expanded. A spider bite may represent a possible causative factor of AGEP. A spider's venom contains sphingomyelinase that stimulates the release of IL8 and GM-CSF, which are involved in AGEP pathogenesis. Whether or not the con-current use of antibiotics has an effect in AGEP appearance when combined with a spider's venom, cannot be excluded.

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

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

    2017-06-30

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    . To investigate this hypothesis, we studied the effect of sex and life history stage on the frequency of kleptoparasitism in ant-eating spiders of the genus Zodarion in the field. These spiders use a special capture technique involving a quick attack on an ant that is left unguarded by spiders for several minutes...... 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...

  7. Inhibition of the spider heartbeat by gravity and vibration

    Science.gov (United States)

    Finck, A.

    1984-01-01

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

  8. Spider silk reinforced by graphene or carbon nanotubes

    Science.gov (United States)

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

    2017-09-01

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

  9. Hemolymph biochemistry reference ranges for wild-caught Goliath birdeater spiders (Theraphosa blondi) and Chilean rose spiders (Grammostola rosea).

    Science.gov (United States)

    Zachariah, Trevor T; Mitchell, Mark A; Guichard, Clare M; Singh, Rimme S

    2007-06-01

    Theraphosid spiders have become increasingly popular for private and public uses in the United States. However, little is known about their physiology from a medical standpoint. This study represents the first attempt to establish reference hemolymph values for two common species of theraphosids, the goliath birdeater spider (Theraphosa blondi) and the Chilean rose spider (Grammostola rosea). Eleven T. blondi and twelve G. rosea, all wild-caught subadults, were obtained after importation and hemolymph was collected for biochemical analysis. After 8 wk of captivity, hemolymph was again collected from the spiders and analyzed. The biochemical analytes measured in the study included aspartate transferase, creatine kinase, glucose, total protein, albumin, uric acid, blood urea nitrogen, phosphorous, calcium, potassium, and sodium. The osmolality of the hemolymph was estimated for each spider using two different formulae. There were significant differences in body weight, sodium, potassium, and osmolality between the sampling times for both species. There were also significant differences in creatine kinase, calcium, total protein, and blood urea nitrogen between sampling periods for T. blondi. The results of this study suggest that serial hemolymph samples may be used to assess the hydration status of theraphosid spiders. In addition, the differences in hemolymph analytes between spiders suggest that there may be differences between species that should be addressed in future studies.

  10. Nuclear DNA variation in spider monkeys (Ateles).

    Science.gov (United States)

    Collins, A C; Dubach, J M

    2001-04-01

    Phylogenetic relationships based on DNA sequence variation for the aldolase A intron V nuclear genomic region were evaluated and compared to phylogenies based on mitochondrial DNA sequence variation among spider monkeys (Ateles). Samples of Ateles ranging from Central America throughout the Amazon Basin were sequenced to determine phylogenetic relationships among geographically widely distributed populations. Analysis of nuclear DNA sequences using parsimony, maximum-likelihood, and genetic distance analyses produced similar phylogenies. Four previously proposed monophyletic species of spider monkeys were: (1) Ateles paniscus, composed of haplotypes from the northeastern Amazon Basin; (2) A. belzebuth, found in the western and southern Amazon Basin; (3) A. hybridus, located primarily along the Magdalena River valley of Colombia; and (4) A. geoffroyi, including all haplotypes found in the Choco region of South America and throughout Central America. The nuclear phylograms were analyzed based on associated bootstrap support and confidence probabilities. Support from the nuclear DNA genome was less robust than support from the mitochondrial DNA data, most likely due to a level of sequence variation, which was 90% less than that of the mitochondrial DNA genome. Nuclear DNA congruencies with mitochondrial DNA-based phylogenies, as supported by the incongruence length difference and winning sites tests, provide further support for the suggested revisions in Ateles taxonomy that are contradictory to long-held taxonomies based on pelage variation. Copyright 2001 Academic Press.

  11. Progress on development of SPIDER diagnostics

    Science.gov (United States)

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

    2017-08-01

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

  12. Spiders (Araneae) Found in Bananas and Other International Cargo Submitted to North American Arachnologists for Identification.

    Science.gov (United States)

    Vetter, Richard S; Crawford, Rodney L; Buckle, Donald J

    2014-11-01

    Spiders found in international cargo brought into North America are sometimes submitted to arachnologists for identification. Often, these spiders are presumed to be of medical importance because of size or a submitter's familiarity with a toxic spider genus from the continent of origin. Starting in 2006, requests were made for spiders found in international cargo brought into North America, in addition to the specimens from similar cargo shipments already in our museum collections. This was an ad hoc study that allowed us to focus on spiders of concern to the discoverer. We identified 135 spiders found in international cargo. A key for the most common species is provided. The most frequently submitted spiders were the pantropical huntsman spider, Heteropoda venatoria (L.) (Sparassidae), and the redfaced banana spider, Cupiennius chiapanensis Medina Soriano (Ctenidae). Spiders of medical importance were rare. The most common cargo from which spiders were submitted was bananas with most specimens coming from Central America, Ecuador, or Colombia. Lack of experience with nonnative fauna caused several experienced American arachnologists to misidentify harmless ctenid spiders (C. chiapanensis, spotlegged banana spider, Cupiennius getazi Simon) as highly toxic Phoneutria spiders. These misidentifications could have led to costly, unwarranted prophylactic eradication measures, unnecessary employee health education, heightened employee anxiety and spoilage when perishable goods are left unloaded due to safety concerns. © 2014 Entomological Society of America.

  13. Organic matter characterization and decomposition dynamics in sub-Antarctic streams impacted by invasive beavers Caracterización de la materia orgánica y la dinámica de descomposición en arroyos subantárticos impactados por castores invasores

    Directory of Open Access Journals (Sweden)

    Erica Ulloa

    2012-11-01

    Full Text Available Despite being a relatively remote and well conserved area, the sub-Antarctic ecoregion faces pressing global threats from climate change, the ozone hole and introduced species. Its freshwater ecosystems are one of the least studied components of this biome, but they are known to confront a host of invasive taxa including trout and beavers. We set out to understand the basic characterization and dynamics of organic matter processing and decomposition in sub-Antarctic streams under natural forest (NF conditions and in ponds constructed by North American beavers (Castor canadensis (BP. We found these streams have a naturally stable benthic organic matter regime throughout the year with a peak in leaf input from Nothofagus pumilio in autumn. Beaver ponds significantly increased the retention of organic matter and caused significantly higher decomposition rates, probably associated with increased density and biomass of Hyalella spp. As expected, leaf decay rates for N. pumilio, a deciduous species, were higher (NF: -0.0028 day- ± 0.0001 SE; BP: -0.0118 day-1 ± 0.0009 SE than N. betuloides (a broad-leaf evergreen (NF: -0.0018 day-1 ± 0.0005 SE; BP: -0.0040 day-1 ± 0.0003 SE. Overall these results indicate that the naturally low decomposition rates (slower than 89% of a global survey of decay rates for these cold, oligotrophic streams are being modified by introduced beavers to resemble more temperate latitudes.A pesar de ser una zona relativamente remota y bien conservado, la ecorregión subantártica se enfrenta a presiones por amenazas globales por el cambio climático, el agujero de ozono y las especies introducidas. Los ecosistemas de agua dulce son uno de los componentes menos estudiados de este bioma, pero se sabe que enfrentan una serie de taxones invasivos como la trucha y los castores. El propósito de este estudio es entender la caracterización básica y dinámica de descomposición de la materia orgánica en arroyos subantárticos de

  14. Evolution of stenophagy in spiders (Araneae): evidence based on the comparative analysis of spider diets.

    Science.gov (United States)

    Pekár, Stano; Coddington, Jonathan A; Blackledge, Todd A

    2012-03-01

    Stenophagy (narrow diet breadth) represents an extreme of trophic specialization in carnivores, but little is known about the forces driving its evolution. We used spiders, the most diversified group of terrestrial predators, to investigate whether stenophagy (1) promoted diversification; (2) was phylogenetically conserved and evolutionarily derived state; and (3) was determined either by geographical distribution and foraging guild. We used published data on the prey of almost 600 species. Six categories of stenophagy were found: myrmecophagy, araneophagy, lepidopterophagy, termitophagy, dipterophagy, and crustaceophagy. We found that the species diversity of euryphagous genera and families was similar to stenophagous genera and families. At the family level, stenophagy evolved repeatedly and independently. Within families, the basal condition was oligophagy or euryphagy. Most types of stenophagy were clearly derived: myrmecophagy in Zodariidae; lepidopterophagy in Araneidae; dipterophagy in Theridiidae. In contrast, araneophagy was confined to basal and intermediate lineages, suggesting its ancestral condition. The diet breadth of species from the tropics and subtropics was less diverse than species from the temperate zone. Diet breadth was lower in cursorial spiders compared to web-building species. Thus, the evolution of stenophagy in spiders appears to be complex and governed by phylogeny as well as by ecological determinants. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  15. Peculiar torsion dynamical response of spider dragline silk

    Science.gov (United States)

    Liu, Dabiao; Yu, Longteng; He, Yuming; Peng, Kai; Liu, Jie; Guan, Juan; Dunstan, D. J.

    2017-07-01

    The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk.

  16. Optical surface profiling of orb-web spider capture silks

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D M; Joyce, A M; Staib, G R [Department of Physics, Macquarie University, Sydney, NSW 2109 (Australia); Herberstein, M E, E-mail: deb.kane@mq.edu.a [Department of Biological Sciences, Macquarie University, Sydney, NSW 2109 (Australia)

    2010-09-15

    Much spider silk research to date has focused on its mechanical properties. However, the webs of many orb-web spiders have evolved for over 136 million years to evade visual detection by insect prey. It is therefore a photonic device in addition to being a mechanical device. Herein we use optical surface profiling of capture silks from the webs of adult female St Andrews cross spiders (Argiope keyserlingi) to successfully measure the geometry of adhesive silk droplets and to show a bowing in the aqueous layer on the spider capture silk between adhesive droplets. Optical surface profiling shows geometric features of the capture silk that have not been previously measured and contributes to understanding the links between the physical form and biological function. The research also demonstrates non-standard use of an optical surface profiler to measure the maximum width of a transparent micro-sized droplet (microlens).

  17. Necrotizing fasciitis developing from a brown recluse spider bite.

    Science.gov (United States)

    Majeski, J

    2001-02-01

    A 20-year retrospective case series was analyzed to identify the brown recluse spider bite as a cause of necrotizing fasciitis. Data from 31 consecutive patients with necrotizing fasciitis were analyzed. Of the 31 patients with necrotizing fasciitis a brown recluse spider bite was found to be the initial cause in two patients. Both patients with spider bites delayed in obtaining medical treatment, and secondary infection of the necrotic tissue occurred. One patient was diagnosed by frozen section tissue biopsy, and the second patient was diagnosed by clinical examination. All patients in this series had immediate aggressive operative debridement. Both patients survived with functional limbs. There were no deaths in this large series. Necrotizing fasciitis can be caused by a secondarily infected brown recluse spider bite. Successful treatment of necrotizing fasciitis from any cause is associated with early diagnosis, immediate surgical debridement, and supplemental enteral or parenteral nutrition.

  18. Evolutionary crossroads in developmental biology: the spider Parasteatoda tepidariorum.

    Science.gov (United States)

    Hilbrant, Maarten; Damen, Wim G M; McGregor, Alistair P

    2012-08-01

    Spiders belong to the chelicerates, which is an arthropod group that branches basally from myriapods, crustaceans and insects. Spiders are thus useful models with which to investigate whether aspects of development are ancestral or derived with respect to the arthropod common ancestor. Moreover, they serve as an important reference point for comparison with the development of other metazoans. Therefore, studies of spider development have made a major contribution to advancing our understanding of the evolution of development. Much of this knowledge has come from studies of the common house spider, Parasteatoda tepidariorum. Here, we describe how the growing number of experimental tools and resources available to study Parasteatoda development have provided novel insights into the evolution of developmental regulation and have furthered our understanding of metazoan body plan evolution.

  19. 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...

  20. A revision of the spider genus Zaitunia (Araneae, Filistatidae)

    National Research Council Canada - National Science Library

    Sergei Zonstein; Yuri M. Marusik

    2016-01-01

    The spider genus Zaitunia Lehtinen, 1967 (Araneae, Filistatidae) is revised. It was found to include 24 species distributed in the Eastern Mediterranean, Middle East and Central Asia: ♀ Z. afghana (Roewer, 1962) (Afghanistan), ♀ Z...

  1. Chemical recognition of fruit ripeness in spider monkeys (Ateles geoffroyi).

    Science.gov (United States)

    Nevo, Omer; Orts Garri, Rosa; Hernandez Salazar, Laura Teresa; Schulz, Stefan; Heymann, Eckhard W; Ayasse, Manfred; Laska, Matthias

    2015-10-06

    Primates are now known to possess well-developed olfactory sensitivity and discrimination capacities that can play a substantial role in many aspects of their interaction with conspecifics and the environment. Several studies have demonstrated that olfactory cues may be useful in fruit selection. Here, using a conditioning paradigm, we show that captive spider monkeys (Ateles geoffroyi) display high olfactory discrimination performance between synthetic odor mixtures mimicking ripe and unripe fruits of two wild, primate-consumed, Neotropical plant species. Further, we show that spider monkeys are able to discriminate the odor of ripe fruits from odors that simulate unripe fruits that become increasingly similar to that of ripe ones. These results suggest that the ability of spider monkeys to identify ripe fruits may not depend on the presence of any individual compound that mark fruit ripeness. Further, the results demonstrate that spider monkeys are able to identify ripe fruits even when the odor signal is accompanied by a substantial degree of noise.

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

    Science.gov (United States)

    Cooke, Alison; Smith, Debbie; Booth, Andrew

    2012-10-01

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

  3. SPIDERS (ARANEI) OF VOLGOGRAD SITY AND ITS ENVIRONS

    OpenAIRE

    A. V. Ponomarev; A. S. Khnykin

    2013-01-01

    Abstract. Aim. Fauna of spiders of Volgograd Region is researched uncompletely. Only 149 species of 19 families were listed in previous references. Complete listing of spiders of this large region was the aim of our investigation.Location. Volgograd Region, Russia.Methods. Material was collected in Volgograd City with environs and Volga-Don area in 2009–2013. Areas with minimum of anthropogenic influence within the city, artificial ecosystem of park type, plots of native vegetation along the ...

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

    DEFF Research Database (Denmark)

    Schneider, J.M.; Bilde, T.

    2008-01-01

    used a cross-fostering design to control for genetic relatedness and group membership. Our study animal was the periodic social spider Stegodyphus lineatus, a transitional species that belongs to a genus containing both permanent social and periodic social species. In S. lineatus, the young cooperate....... Hence, in communally feeding spiders, nepotism favors group retention and reduces the conflict between selfish interests and the interests of the group....

  5. Mechanics and Morphology of Silk Drawn from Anesthetized Spiders

    Science.gov (United States)

    Madsen, B.; Vollrath, F.

    CO2 and N2 anesthetized Nephila spiders produced dragline silk with mechanical properties that differed from control silk as a function of time under anesthesia. Silk from CO2 spiders had a significantly lower breaking strain and breaking energy, significantly higher initial modulus, and marginally lower breaking stress. At the onset of anesthesia the silk diameter became highly variable. During deep anesthesia silk either became thinner or retained cross-section but fibrillated.

  6. Biotechnological Trends in Spider and Scorpion Antivenom Development

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Solà, Mireia; Jappe, Emma Christine

    2016-01-01

    at an increasingly faster pace. In this review, the current knowledge of spider and scorpion venoms is presented, followed by a discussion of all published biotechnological efforts within development of spider and scorpion antitoxins based on small molecules, antibodies and fragments thereof, and next generation...... immunization strategies. The increasing number of discovery and development efforts within this field may point towards an upcoming transition from serum-based antivenoms towards therapeutic solutions based on modern biotechnology....

  7. Brown recluse spider's nanometer scale ribbons of stiff extensible silk.

    Science.gov (United States)

    Schniepp, Hannes C; Koebley, Sean R; Vollrath, Fritz

    2013-12-23

    The silk of the recluse spider features a ribbon-like morphology unlike any other spider silk or synthetically spun polymer fiber. These protein ribbons represent free-standing polymer films with a thickness of about 50 nm. Stress-strain characterization of individual fibers via atomic force microscopy reveals that these ribbons, only a few molecular layers of protein thin, rival the mechanical performance of the best silks. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Spider silk as a blueprint for greener materials : a review

    OpenAIRE

    Lefèvre, Thierry; Auger, Michèle

    2016-01-01

    Spider silk exhibits remarkable properties, especially its well-known tensile performances. They rely on a complex nanostructured hierarchical organisation that studies progressively elucidate. Spider silk encompasses a vast range of fibres that exhibit diverse and captivating physical and biological characteristics. The full understanding of the relation between structure and properties may lead in the future to the design of a variety of high-performance, tailored materials and ...

  9. Spider sedation induced by defensive chemicals of milliped prey*

    OpenAIRE

    Carrel, James E.; Eisner, Thomas

    1984-01-01

    Wolf spiders (Lycosa spp.) show delayed induced sedation (total immobilization) of prolonged duration (in the order of days) after attacks upon millipeds (Glomeris marginata). The sedation is specifically attributable to glomerin and homoglomerin, two previously characterized quinazolinones present in the defensive secretion of Glomeris. Median sedative doses for the quinazolinones are in the range of 1-7 μg per spider, a fraction of the total (60-90 μg) present in the secretion of medium to ...

  10. 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, o...... 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....

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

    Directory of Open Access Journals (Sweden)

    Bilde Trine

    2009-10-01

    Full Text Available Abstract Background Cooperative hunting and foraging in spiders is rare and prone to cheating such that the actions of selfish individuals negatively affect the whole group. The resulting social dilemma may be mitigated by kin selection since related individuals lose indirect fitness benefits by acting selfishly. Indeed, cooperation with genetic kin reduces the disadvantages of within-group competition in the subsocial spider Stegodyphus lineatus, supporting the hypothesis that high relatedness is an important pre-adaptation in the transition to sociality in spiders. In this study we examined the consequences of group size and relatedness on cooperative feeding in the subsocial spider S. tentoriicola, a species suggested to be at the transition to permanent sociality. Results We formed groups of 3 and 6 spiders that were either siblings or non-siblings. We found that increasing group size negatively affected feeding efficiency but that these negative effects were reduced in sib-groups. Sib groups were more likely to feed cooperatively and all group members grew more homogenously than groups of unrelated spiders. The measured differences did not translate into differential growth or mortality during the experimental period of 8 weeks. Conclusion The combination of our results with those from previous studies indicates that the conflict between individual interests and group interests may be reduced by nepotism and that the latter promote the maintenance of the social community.

  12. Nutrient Deprivation Induces Property Variations in Spider Gluey Silk

    Science.gov (United States)

    Blamires, Sean J.; Sahni, Vasav; Dhinojwala, Ali; Blackledge, Todd A.; Tso, I-Min

    2014-01-01

    Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition. PMID:24523902

  13. Impact of prescribed burning on a heathland inhabiting spider community

    Directory of Open Access Journals (Sweden)

    Krause, Rolf Harald

    2016-04-01

    Full Text Available Heathlands can provide refuge for many stenotopic and endangered arthropods, if habitat management practices are applied. A management measure that is rarely being used today, but which has the potential to support diversity of arthropod communities, is prescribed burning. In this study we investigated the effects of prescribed burning on spider assemblages on a burned site with Calluna vulgaris in the nature reserve Lueneburg Heath, northwest Germany. We used pitfall trapping with a sampling design of 39 traps over a period of one year and 17 sampling intervals on a burned and a control site. We compared overall species richness, activity abundance patterns and community composition of the two sites, with a particular focus on stenotopic and endangered species. We collected 5116 adult spiders and 99 species altogether in a relatively small sampling area. This number of species represents nearly one third of the regional species pool of heathland spider species. Twelve species occurred exclusively on the burned site in contrast to 28 species exclusively found on the unburned site. Although we found more than twice as many spider individuals and higher mean species richness on the control site than on the burned site, the species richness of red-listed spiders was higher on the burned site. Especially the fact that we found 24 endangered species on the burned site and only 20 on the control site indicates that the applied measure of prescribed burning can foster certain endangered spider species and contribute to preserving the overall biodiversity of heathland ecosystems.

  14. SPIDERS (ARANEI OF VOLGOGRAD SITY AND ITS ENVIRONS

    Directory of Open Access Journals (Sweden)

    A. V. Ponomarev

    2013-01-01

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

  15. Adaptive aggregation by spider mites under predation risk.

    Science.gov (United States)

    Dittmann, Lena; Schausberger, Peter

    2017-09-06

    Grouping together is a commonly observed anti-predator strategy. Possible anti-predator benefits of aggregation include the encounter/avoidance effect for visually hunting predators and the dilution effect, together dubbed attack abatement. Possible costs opposing the dilution effect are easier detection of aggregated than scattered individuals. The benefits of attack abatement, and opposing costs after group detection, are poorly understood for chemosensory predator-prey interactions. We tackled this issue by assessing the aggregation behavior of spider mites Tetranychus urticae under predation risk emanating from predatory mites Phytoseiulus persimilis. We examined whether adult spider mite females aggregate more tightly when perceiving predator cues (traces left and eggs), representing graded risk levels, and whether grouping enhances survival in physical predator presence. The spider mites aggregated more tightly and were more active in presence than absence of predator cues. Grouped spider mites were less likely and later detected and attacked than scattered spider mites. Moreover, encounter and attack of one group member did not increase the risk of other members to be attacked, as compared to scattered spider mites. To the best of our knowledge, our study is the first rigorous documentation of the adaptive benefit of tightened prey aggregation towards a purely chemosensorily hunting predator.

  16. 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.

  17. Biodiversity baseline of the French Guiana spider fauna.

    Science.gov (United States)

    Vedel, Vincent; Rheims, Christina; Murienne, Jérôme; Brescovit, Antonio Domingos

    2013-01-01

    The need for an updated list of spiders found in French Guiana rose recently due to many upcoming studies planned. In this paper, we list spiders from French Guiana from existing literature (with corrected nomenclature when necessary) and from 2142 spiders sampled in 12 sites for this baseline study. Three hundred and sixty four validated species names of spider were found in the literature and previous authors' works. Additional sampling, conducted for this study added another 89 identified species and 62 other species with only a genus name for now. The total species of spiders sampled in French Guiana is currently 515. Many other Morphospecies were found but not described as species yet. An accumulation curve was drawn with seven of the sampling sites and shows no plateau yet. Therefore, the number of species inhabiting French Guiana cannot yet be determined. As the very large number of singletons found in the collected materials suggests, the accumulation curve indicates nevertheless that more sampling is necessary to discover the many unknown spider species living in French Guiana, with a focus on specific periods (dry season and wet season) and on specific and poorly studied habitats such as canopy, inselberg and cambrouze (local bamboo monospecific forest).

  18. Isoflurane anesthesia of wild-caught goliath birdeater spiders (Theraphosa blondi) and Chilean rose spiders (Grammostola rosea).

    Science.gov (United States)

    Zachariah, Trevor T; Mitchell, Mark A; Guichard, Clare M; Singh, Rimme S

    2009-06-01

    Anesthesia is used in theraphosid spiders to facilitate medical procedures (e.g., physical examination, sample collection, surgery); however, most information on this subject is anecdotal. This study was conducted to systematically determine the anesthetic parameters of wild-caught, subadult goliath birdeater spiders (Theraphosa blondi) (n = 11) and Chilean rose spiders (Grammostola rosea) (n = 12). Each spider was placed in a 3-L gas anesthetic chamber and subjected to an induction of 5% isoflurane at a rate of 1 L/min oxygen. Anesthetic depth was monitored by evaluating the righting reflex every 5 min. Animals were recovered in 100% oxygen. Induction, recovery, and overall anesthetic times were determined. After an 8-wk washout period, the procedure was repeated. For both species, median induction time was 10 min. Median recovery time was 30 min for T. blondi and 12.5 min for G. rosea.

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

    OpenAIRE

    Wenjin Gan; Shengjie Liu; Xiaodong Yang; Daiqin Li; Chaoliang Lei

    2015-01-01

    ABSTRACT 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 conspecif...

  20. The phylogeny of fossil whip spiders.

    Science.gov (United States)

    Garwood, Russell J; Dunlop, Jason A; Knecht, Brian J; Hegna, Thomas A

    2017-04-21

    Arachnids are a highly successful group of land-dwelling arthropods. They are major contributors to modern terrestrial ecosystems, and have a deep evolutionary history. Whip spiders (Arachnida, Amblypygi), are one of the smaller arachnid orders with ca. 190 living species. Here we restudy one of the oldest fossil representatives of the group, Graeophonus anglicus Pocock, 1911 from the Late Carboniferous (Duckmantian, ca. 315 Ma) British Middle Coal Measures of the West Midlands, UK. Using X-ray microtomography, our principal aim was to resolve details of the limbs and mouthparts which would allow us to test whether this fossil belongs in the extant, relict family Paracharontidae; represented today by a single, blind species Paracharon caecus Hansen, 1921. Tomography reveals several novel and significant character states for G. anglicus; most notably in the chelicerae, pedipalps and walking legs. These allowed it to be scored into a phylogenetic analysis together with the recently described Paracharonopsis cambayensis Engel & Grimaldi, 2014 from the Eocene (ca. 52 Ma) Cambay amber, and Kronocharon prendinii Engel & Grimaldi, 2014 from Cretaceous (ca. 99 Ma) Burmese amber. We recovered relationships of the form ((Graeophonus (Paracharonopsis + Paracharon)) + (Charinus (Stygophrynus (Kronocharon (Charon (Musicodamon + Paraphrynus)))))). This tree largely reflects Peter Weygoldt's 1996 classification with its basic split into Paleoamblypygi and Euamblypygi lineages; we were able to score several of his characters for the first time in fossils. Our analysis draws into question the monophyly of the family Charontidae. Our data suggest that Graeophonus is a crown group amblypygid, and falls within a monophyletic Paleoamblypgi clade, but outside the family Paracharontidae (= Paracharonopsis + Paracharon). Our results also suggest a new placement for the Burmese amber genus Kronocharon, a node further down from its original position. Overall, we offer a

  1. Intersexual Trophic Niche Partitioning in an Ant-Eating Spider (Araneae: Zodariidae)

    National Research Council Canada - National Science Library

    Pekar, Stano; Martisova, Martina; Bilde, Trine

    2011-01-01

    .... 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...

  2. Molecular cloning and expression of the C-terminus of spider ...

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    . Among the types of spider silks, draglines from Nephila clavipes and Araneus diadematus have been the most intensely studied. However, the entirety of a spider silk gene has not been cloned yet, and sequence data from. Molecular cloning ...

  3. Spider Web DNA: A New Spin on Noninvasive Genetics of Predator and Prey

    Science.gov (United States)

    Xu, Charles C. Y.; Yen, Ivy J.; Bowman, Dean; Turner, Cameron R.

    2015-01-01

    Noninvasive genetic sampling enables biomonitoring without the need to directly observe or disturb target organisms. This paper describes a novel and promising source of noninvasive spider and insect DNA from spider webs. Using black widow spiders (Latrodectus spp.) fed with house crickets (Acheta domesticus), we successfully extracted, amplified, and sequenced mitochondrial DNA from spider web samples that identified both spider and prey to species. Detectability of spider DNA did not differ between assays with amplicon sizes from 135 to 497 base pairs. Spider and prey DNA remained detectable at least 88 days after living organisms were no longer present on the web. Spider web DNA as a proof-of-concept may open doors to other practical applications in conservation research, pest management, biogeography studies, and biodiversity assessments. PMID:26606730

  4. Spider Web DNA: A New Spin on Noninvasive Genetics of Predator and Prey.

    Directory of Open Access Journals (Sweden)

    Charles C Y Xu

    Full Text Available Noninvasive genetic sampling enables biomonitoring without the need to directly observe or disturb target organisms. This paper describes a novel and promising source of noninvasive spider and insect DNA from spider webs. Using black widow spiders (Latrodectus spp. fed with house crickets (Acheta domesticus, we successfully extracted, amplified, and sequenced mitochondrial DNA from spider web samples that identified both spider and prey to species. Detectability of spider DNA did not differ between assays with amplicon sizes from 135 to 497 base pairs. Spider and prey DNA remained detectable at least 88 days after living organisms were no longer present on the web. Spider web DNA as a proof-of-concept may open doors to other practical applications in conservation research, pest management, biogeography studies, and biodiversity assessments.

  5. First report of clinical presentation of a bite by a running spider ...

    African Journals Online (AJOL)

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

  6. 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.

  7. Endemic harvestmen and spiders of Austria (Arachnida: Opiliones, Araneae

    Directory of Open Access Journals (Sweden)

    Komposch, Christian

    2011-01-01

    Full Text Available A comprehensive overview of plant, fungus and animal species of Austria revealed a total of 748 endemic and subendemic species, including, 11 harvestman and 46 spider species. Altogether two endemic harvestmen (Nemastoma bidentatum relictum, Nemastoma schuelleri and 8 endemic spiders (Abacoproeces molestus, Collinsia (caliginosa nemenziana, Mughiphantes severus, Mughiphantes styriacus, Pelecopsis alpica, Scotophaeus nanus, Troglohyphantes novicordis, Troglohyphantes tauriscus, beside 9 subendemic harvestman and 38 subendemic spider species have been recorded from Austria. Hot-spots of endemism in the Eastern Alps are the north-eastern (Ennstaler Alps and southern Calcareous Alps (Karawanken, Karnische Alps and the Central Alps (Hohe Tauern, Gurktaler Alps, Ötztaler and Stubaier Alps. Most of the endemic arachnid species occur from the nival down to the montane zone. Important habitats are rocky areas, caves and woodlands. High absolute numbers and percentages of endemics can be found within the harvestman families Cladonychiidae, Ischyropsalididae and Nemastomatidae and in the spider genera Lepthyphantes s. l. and Troglohyphantes. The conservation status of these highly endangered taxa – 85 % of the spider species and 100 % of the harvestman taxa are endangered in Austria – is poor.

  8. 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.

  9. Treatment effect on biases in size estimation in spider phobia.

    Science.gov (United States)

    Shiban, Youssef; Fruth, Martina B; Pauli, Paul; Kinateder, Max; Reichenberger, Jonas; Mühlberger, Andreas

    2016-12-01

    The current study investigates biases in size estimations made by spider-phobic and healthy participants before and after treatment. Forty-one spider-phobic and 20 healthy participants received virtual reality (VR) exposure treatment and were then asked to rate the size of a real spider immediately before and, on average, 15days after the treatment. During the VR exposure treatment skin conductance response was assessed. Prior to the treatment, both groups tended to overestimate the size of the spider, but this size estimation bias was significantly larger in the phobic group than in the control group. The VR exposure treatment reduced this bias, which was reflected in a significantly smaller size rating post treatment. However, the size estimation bias was unrelated to the skin conductance response. Our results confirm the hypothesis that size estimation by spider-phobic patients is biased. This bias is not stable over time and can be decreased with adequate treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Phylogenomic analysis of spiders reveals nonmonophyly of orb weavers.

    Science.gov (United States)

    Fernández, Rosa; Hormiga, Gustavo; Giribet, Gonzalo

    2014-08-04

    Spiders constitute one of the most successful clades of terrestrial predators. Their extraordinary diversity, paralleled only by some insects and mites, is often attributed to the use of silk, and, in one of the largest lineages, to stereotyped behaviors for building foraging webs of remarkable biomechanical properties. However, our understanding of higher-level spider relationships is poor and is largely based on morphology. Prior molecular efforts have focused on a handful of genes but have provided little resolution to key questions such as the origin of the orb weavers. We apply a next-generation sequencing approach to resolve spider phylogeny, examining the relationships among its major lineages. We further explore possible pitfalls in phylogenomic reconstruction, including missing data, unequal rates of evolution, and others. Analyses of multiple data sets all agree on the basic structure of the spider tree and all reject the long-accepted monophyly of Orbiculariae, by placing the cribellate orb weavers (Deinopoidea) with other groups and not with the ecribellate orb weavers (Araneoidea). These results imply independent origins for the two types of orb webs (cribellate and ecribellate) or a much more ancestral origin of the orb web with subsequent loss in the so-called RTA clade. Either alternative demands a major reevaluation of our current understanding of the spider evolutionary chronicle. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Wenjin Gan

    2015-10-01

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

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

    Science.gov (United States)

    Gan, Wenjin; Liu, Shengjie; Yang, Xiaodong; Li, Daiqin; Lei, Chaoliang

    2015-09-24

    A striking feature of web-building spiders is the use of silk to make webs, mainly for prey capture. However, building a web is energetically expensive and increases the risk of predation. To reduce such costs and still have access to abundant prey, some web-building spiders have evolved web invasion behaviour. In general, no consistent patterns of web invasion have emerged and the factors determining web invasion remain largely unexplored. Here we report web invasion among conspecifics in seven nocturnal species of orb-web spiders, and examined the factors determining the probability of webs that could be invaded and taken over by conspecifics. About 36% of webs were invaded by conspecifics, and 25% of invaded webs were taken over by the invaders. A web that was built higher and intercepted more prey was more likely to be invaded. Once a web was invaded, the smaller the size of the resident spider, the more likely its web would be taken over by the invader. This study suggests that web invasion, as a possible way of reducing costs, may be widespread in nocturnal orb-web spiders. © 2015. Published by The Company of Biologists Ltd.

  13. Diagnoses of brown recluse spider bites (loxoscelism) greatly outnumber actual verifications of the spider in four western American states.

    Science.gov (United States)

    Vetter, Richard S; Cushing, Paula E; Crawford, Rodney L; Royce, Lynn A

    2003-09-15

    We attempt to demonstrate that physicians overdiagnose loxoscelism (colloquially known as 'brown recluse spider bites') by comparing the numbers of such diagnoses to the historically known numbers of Loxosceles spiders from the same areas in four western American states. The medical community from non-endemic Loxosceles areas often makes loxoscelism diagnoses solely on the basis of dermonecrotic lesions where Loxosceles spiders are rare or non-existent. If these diagnoses were correct then Loxosceles populations should be evident, specimens should readily be collected over the years and there should be a reasonable correlation between diagnoses and spider specimens. In 41 months of data collection, we were informed of 216 loxoscelism diagnoses from California, Oregon, Washington and Colorado. In contrast, from these four states, we can only find historical evidence of 35 brown recluse or Mediterranean recluse spiders. There is no consistency between localities of known Loxosceles populations and loxoscelism diagnoses. There are many conditions of diverse etiology that manifest in dermonecrosis. In the western United States, physician familiarity with these conditions will lead to more accurate diagnoses and subsequent proper remedy.

  14. Influence of spider silk on refugia preferences of the recluse spiders Loxosceles reclusa and Loxosceles laeta (Araneae: Sicariidae).

    Science.gov (United States)

    Vetter, Richard S; Rust, Michael K

    2010-06-01

    In a previous experimental study, recluse spiders Loxosceles reclusa Gertsch and Mulaik and Loxosceles laeta (Nicolet) (Araneae: Sicariidae) preferred small cardboard refugia covered with conspecific silk compared with never-occupied refugia. Herein, we investigated some factors that might be responsible for this preference using similar cardboard refugia. When the two Loxosceles species were given choices between refugia previously occupied by their own and by the congeneric species, neither showed a species-specific preference; however, each chose refugia coated with conspecific silk rather than those previously inhabited by a distantly related cribellate spider, Metaltella simoni (Keyserling). When L. laeta spiders were offered refugia that were freshly removed from silk donors compared with heated, aged refugia from the same silk donor, older refugia were preferred. Solvent extracts of L. laeta silk were chosen approximately as often as control refugia when a range of solvents (methylene chloride:methanol, water, and hexane) were used. However, when acetone was used on similar silk, there was a statistical preference for the control, indicating that there might be a mildly repellent aspect to acetone-washed silk. Considering the inability to show attraction to chemical aspects of fresh silk, it seems that physical attributes may be more important for selection and that there might be repellency to silk of a recently vacated spider. These findings are discussed in regard to pest management strategies to control recluse spiders.

  15. Freshwater invertebrates of sub-Antarctic Marion Island | Dartnall ...

    African Journals Online (AJOL)

    Antarctic Marion Island were examined for invertebrates. Sixty-eight species were found, including 45 new records for the Island. Of these 56 were bona fide aquatic invertebrates, the rest being terrestrial or brackish interlopers that had fallen or been ...

  16. Development of homeothermy in chicks of sub-Antarctic burrowing ...

    African Journals Online (AJOL)

    On average, chicks of grey petrels, great-winged petrels and Salvin's prions attained homeothermy within five days of hatching, but some individuals exhibited well-developed homeothermy within 24 h of hatching. Chicks demonstrated a high capacity for heat production and maximum cold-induced oxygen consumptions ...

  17. Development of homeothermy in chicks of sub-Antarctic burrowing ...

    African Journals Online (AJOL)

    1988-05-06

    May 6, 1988 ... city for heat production and maximum cold-induced oxygen consumptions ranged from 2,57 ml O2 g-l h-1 in white-chinned petrel chicks to 4,94 ml O2 ... of petrel chicks to cold stress are less well reported. (Ricklefs, White & Cullen 1980; ... thermoregulatory ability of the chicks. Grey petrels and greatwinged ...

  18. How spiders practice aggressive and Batesian mimicry

    Directory of Open Access Journals (Sweden)

    Ximena J. NELSON, Robert R. JACKSON

    2012-08-01

    Full Text Available 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 [Current Zoology 58 (4: 620–629, 2012].

  19. Thermal architecture for the SPIDER flight cryostat

    Science.gov (United States)

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

    2010-07-01

    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 3He 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 cryogenic system.

  20. How to visualize the spider mite silk?

    Science.gov (United States)

    Clotuche, G; Le Goff, G; Mailleux, A-C; Deneubourg, J-L; Detrain, C; Hance, T

    2009-09-01

    Tetranychus urticae (Acari: Tetranychidae) is a phytophagous mite that forms colonies of several thousand individuals. Like spiders, every individual produces abundant silk strands and is able to construct a common web for the entire colony. Despite the importance of this silk for the biology of this worldwide species, only one previous study suggested how to visualize it. To analyze the web structuration, we developed a simple technique to dye T. urticae'silk on both inert and living substrates. Fluorescent brightener 28 (FB) (Sigma F3543) diluted in different solvents at different concentrations regarding the substrate was used to observe single strands of silk. On glass lenses, a 0.5% dimethyl sulfoxide solution was used and on bean leaves, a 0.1% aqueous solution. A difference of silk deposit was observed depending the substrate: rectilinear threads on glass lenses and more sinuous ones on bean leaves. This visualizing technique will help to carry out future studies about the web architecture and silk used by T. urticae. It might also be useful for the study of other silk-spinning arthropods.

  1. Synthetic Adhesive Attachment Discs based on Spider Pyriform Silk Architecture

    Science.gov (United States)

    Jain, Dharamdeep; Sahni, Vasav; Dhinojwala, Ali

    2014-03-01

    Among the variety of silks produced by spiders, pyriform silk is used in conjunction with the dragline silk to attach webs to different surfaces. Cob weaver spiders employ different architectural patterns to utilize the pyriform silk and form attachment joints with each pattern having a characteristic adhesive performance. The staple pin architecture is a one of the strongest attachment designs employed by spiders to attach their webs. Here we use a synthetic approach to create the a similar patterned architecture attachment discs on aluminum substrate using thermoplastic polyurethane. Measurable pull off forces are generated when the synthetic discs are peeled off a surface. This innovative adhesive strategy can be a source of design in various biomedical applications. Financial Support from National Science Foundation.

  2. Final design of thermal diagnostic system in SPIDER ion source

    Energy Technology Data Exchange (ETDEWEB)

    Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Dalla Palma, M.; Pasqualotto, R.; Pomaro, N. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2016-11-15

    The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H{sup −} production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements. This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.

  3. Web-building spiders attract prey by storing decaying matter

    Science.gov (United States)

    Bjorkman-Chiswell, Bojun T.; Kulinski, Melissa M.; Muscat, Robert L.; Nguyen, Kim A.; Norton, Briony A.; Symonds, Matthew R. E.; Westhorpe, Gina E.; Elgar, Mark A.

    The orb-weaving spider Nephila edulis incorporates into its web a band of decaying animal and plant matter. While earlier studies demonstrate that larger spiders utilise these debris bands as caches of food, the presence of plant matter suggests additional functions. When organic and plastic items were placed in the webs of N. edulis, some of the former but none of the latter were incorporated into the debris band. Using an Y-maze olfactometer, we show that sheep blowflies Lucilia cuprina are attracted to recently collected debris bands, but that this attraction does not persist over time. These data reveal an entirely novel foraging strategy, in which a sit-and-wait predator attracts insect prey by utilising the odours of decaying organic material. The spider's habit of replenishing the debris band may be necessary to maintain its efficacy for attracting prey.

  4. Adhesion modulation using glue droplet spreading in spider capture silk.

    Science.gov (United States)

    Amarpuri, Gaurav; Zhang, Ci; Blackledge, Todd A; Dhinojwala, Ali

    2017-05-01

    Orb web spiders use sticky capture spiral silk to retain prey in webs. Capture spiral silk is composed of an axial fibre of flagelliform silk covered with glue droplets that are arranged in a beads-on-a-string morphology that allows multiple droplets to simultaneously extend and resist pull off. Previous studies showed that the adhesion of capture silk is responsive to environmental humidity, increasing up to an optimum humidity that varied among different spider species. The maximum adhesion was hypothesized to occur when the viscoelasticity of the glue optimized contributions from glue spreading and bulk cohesion. In this study, we show how glue droplet shape during peeling contributes significantly to capture silk adhesion. Both overspreading and underspreading of glue droplets reduces adhesion through changes in crack propagation and failure regime. Understanding the mechanism of stimuli-responsive adhesion of spider capture silk will lead to new designs for smarter adhesives. © 2017 The Author(s).

  5. New data on spider fauna from northern Serbia

    Directory of Open Access Journals (Sweden)

    Dudić B.D.

    2013-01-01

    Full Text Available During two years of research on the epigeic fauna in agroecosystems of northern Serbia, which was conducted as a part of SEE-ERA NET PLUS project no. 51, 5488 spider specimens were collected at three fields with oilseed rape (Brassica napus var. oleifera, turnip rape (Brassica rapa x chinensis and winter wheat (Triticum aestivum as subsequent crop at Stari Žednik (Vojvodina. A total of 62 species from 15 families were identified. Pardosa agrestis and Xysticus kochi were the dominant species in the studied fields. Spider families with significant presence were Lycosidae, Linyphiidae, Thomisidae, Gnaphosidae, Theridiidae and Philodromidae. Seven species are new to the spider fauna of Serbia. [Projekat Ministarstva nauke Republike Srbije, br. 173038

  6. Recombinant Spider Silks—Biopolymers with Potential for Future Applications

    Directory of Open Access Journals (Sweden)

    Thomas Scheibel

    2011-03-01

    Full Text Available Nature has evolved a range of materials that compete with man-made materials in physical properties; one of these is spider silk. Silk is a fibrous material that exhibits extremely high strength and toughness with regard to its low density. In this review we discuss the molecular structure of spider silk and how this understanding has allowed the development of recombinant silk proteins that mimic the properties of natural spider silks. Additionally, we will explore the material morphologies and the applications of these proteins. Finally, we will look at attempts to combine the silk structure with chemical polymers and how the structure of silk has inspired the engineering of novel polymers.

  7. Final design of thermal diagnostic system in SPIDER ion source

    Science.gov (United States)

    Brombin, M.; Dalla Palma, M.; Pasqualotto, R.; Pomaro, N.

    2016-11-01

    The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H- production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements. This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.

  8. Spider fauna of semiarid eastern Colorado agroecosystems: diversity, abundance, and effects of crop intensification.

    Science.gov (United States)

    Kerzicnik, Lauren M; Peairs, Frank B; Cushing, Paula E; Draney, Michael L; Merrill, Scott C

    2013-02-01

    Spiders are critical predators in agroecosystems. Crop management practices can influence predator density and diversity, which, in turn, can influence pest management strategies. Crop intensification is a sustainable agricultural technique that can enhance crop production although optimizing soil moisture. To date, there is no information on how crop intensification affects natural enemy populations, particularly spiders. This study had two objectives: to characterize the abundance and diversity of spiders in eastern Colorado agroecosystems, and to test the hypothesis that spider diversity and density would be higher in wheat (Triticum aestivum L.) in crop-intensified rotations compared with wheat in conventional rotations. We collected spiders through pitfall, vacuum, and lookdown sampling from 2002 to 2007 to test these objectives. Over 11,000 spiders in 19 families from 119 species were captured from all sampling techniques. Interestingly, the hunting spider guild represented 89% of the spider fauna captured from all sites with the families Gnaphosidae and Lycosidae representing 75% of these spiders. Compared with European agroecosystems, these agroecosystems had greater diversity, which can be beneficial for the biological control of pests. Overall, spider densities were low in these semiarid cropping systems, and crop intensification effects on spider densities were not evident at this scale.

  9. Nutrient deprivation induces property variations in spider gluey silk.

    Directory of Open Access Journals (Sweden)

    Sean J Blamires

    Full Text Available Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition.

  10. Prey type, vibrations and handling interactively influence spider silk expression.

    Science.gov (United States)

    Blamires, S J; Chao, I-C; Tso, I-M

    2010-11-15

    The chemical and mechanical properties of spider major ampullate (MA) silks vary in response to different prey, mostly via differential expression of two genes - MaSp1 and MaSp2 - although the spinning process exerts additional influence over the mechanical properties of silk. The prey cues that initiate differential gene expression are unknown. Prey nutrients, vibratory stimuli and handling have been suggested to be influential. We performed experiments to decouple the vibratory stimuli and handling associated with high and low kinetic energy prey (crickets vs flies) from their prey nutrients to test the relative influence of each as inducers of silk protein expression in the orb web spider Nephila pilipes. We found that the MA silks from spiders feeding on live crickets had greater percentages of glutamine, serine, alanine and glycine than those from spiders feeding on live flies. Proline composition of the silks was unaffected by feeding treatment. Increases in alanine and glycine in the MA silks of the live-cricket-feeding spiders indicate a probable increase in MaSp1 gene expression. The amino acid compositions of N. pilipes feeding on crickets with fly stimuli and N. pilipes feeding on flies with cricket stimuli did not differ from each other or from pre-treatment responses, so these feeding treatments did not induce differential MaSp expression. Our results indicate that cricket vibratory stimuli and handling interact with nutrients to induce N. pilipes to adjust their gene expression to produce webs with mechanical properties appropriate for the retention of this prey. This shows that spiders can genetically alter their silk chemical compositions and, presumably, mechanical properties upon exposure to different prey types. The lack of any change in proline composition with feeding treatment in N. pilipes suggests that the MaSp model determined for Nephila clavipes is not universally applicable to all Nephila.

  11. A preliminary checklist of spiders (Araneae: Arachnida in Chinnar Wildlife Sanctuary, Western Ghats, India

    Directory of Open Access Journals (Sweden)

    C. K. Adarsh

    2016-04-01

    Full Text Available A preliminary study was conducted to document spider diversity in Chinnar Wildlife Sanctuary, Idukki District, Kerala State in southern India.  The study was conducted from October to November 2012.  A total of 101 species of spiders belonging to 65 genera from 29 families were identified from the sanctuary.  This accounted for 6.98% of Indian spider species, 17.81% of Indian spider genera and 48.33% of the spider families of India.  The dominant families were Lycosidae (11 species and Araneidae (10.  Two endemic genera of Indian spiders such as Annandaliella and Neoheterophrictus were found at Chinnar, each representing one species each, and belonging to the family Theraphosidae.  A guild structure analysis of the spiders revealed seven feeding guilds such as orb weavers, stalkers, ground runners, foliage runners, sheet web builders, space web builders and ambushers. 

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

    Directory of Open Access Journals (Sweden)

    Machač, Ondřej

    2016-04-01

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

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

    Science.gov (United States)

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

    2012-12-23

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

  14. Contamination vs. harm-relevant outcome expectancies and covariation bias in spider phobia.

    Science.gov (United States)

    de Jong, Peter J; Peters, Madelon L

    2007-06-01

    There is increasing evidence that spiders are not feared because of harmful outcome expectancies but because of disgust and contamination-relevant outcome expectancies. This study investigated the relative strength of contamination- and harm-relevant UCS expectancies and covariation bias in spider phobia. High (n=25) and low (n=24) spider fearful individuals saw a series of slides comprising spiders, pitbulls, maggots, and rabbits. Slides were randomly paired with either a harm-relevant outcome (electrical shock), a contamination-related outcome (drinking of a distasting fluid), or nothing. Spider fearful individuals displayed a contamination-relevant UCS expectancy bias associated with spiders, whereas controls displayed a harm-relevant expectancy bias. There was no evidence for a (differential) postexperimental covariation bias; thus the biased expectancies were not robust against refutation. The present findings add to the evidence that contamination ideation is critically involved in spider phobia.

  15. Brown recluse spider bites: a complex problem wound. A brief review and case study.

    Science.gov (United States)

    Wilson, Judy R; Hagood, Clyde O; Prather, Irvine D

    2005-03-01

    Brown recluse spiders (Loxosceles reclusa) are responsible for virtually all documented cases of spider bites leading to significant necrosis. The actual spider bite often goes unnoticed for as long as 4 to 6 hours, which makes diagnosis and, therefore, appropriate treatment, difficult. The spider bite generally results in either a necrotic wound or systemic symptoms that can lead to hemolysis. The patient described in this article experienced both complications. Dapsone and hyperbaric oxygen therapy brought the adverse response to the bite under control. The patient was hospitalized for 7 days during treatment for hemolysis and an extensive, necrotic wound. Efforts are underway to develop an assay to provide a definitive diagnosis for the brown recluse spider bite, but none is yet commercially available. Antivenom is scarce; capture of the offending spider appears to be most helpful in the diagnosis and proper treatment of spider bites.

  16. Shear-induced rigidity in spider silk glands

    Science.gov (United States)

    Koski, Kristie J.; McKiernan, Keri; Akhenblit, Paul; Yarger, Jeffery L.

    2012-09-01

    We measure the elastic stiffnesses of the concentrated viscous protein solution of the dehydrated Nephila clavipes major ampullate gland with Brillouin light scattering. The glandular material shows no rigidity but possesses a tensile stiffness similar to that of spider silk. We show, however, that with application of a simple static shear, the mechanical properties of the spider gland protein mixture can be altered irreversibly, lowering symmetry and enabling shear waves to be supported, thus, giving rise to rigidity and yielding elastic properties similar to those of the naturally spun (i.e., dynamically sheared) silk.

  17. Arachnids submitted as suspected brown recluse spiders (Araneae: Sicariidae): Loxosceles spiders are virtually restricted to their known distributions but are perceived to exist throughout the United States.

    Science.gov (United States)

    Vetter, Richard S

    2005-07-01

    An Internet offer was made to identify any spider in the United States perceived to be a brown recluse spider, Loxosceles reclusa Gertsch & Mulaik (Sicariidae). In total, 1,773 arachnids from 49 states represented three orders (Araneae, Solifugae, and Opiliones) and the identifiable spiders (Araneae) consisted of 38 families, 88 genera, and 158 recognizable species. Participants from states at least half within the known brown recluse distribution submitted Loxosceles spiders 32- 89% of the time, except Louisiana and Mississippi with no submissions. From 25 of 29 states completely or almost completely outside of the range of Loxosceles spiders, no recluse spiders were submitted. Only two discoveries of brown recluses and two of the worldwide tramp species Loxosceles rufescens (Dufour) were submitted from nonendemic Loxosceles areas. States on distribution margins of brown recluse or other native Loxosceles spiders were intermediate in their Loxosceles submissions. This study showed that 1) the general public perceives brown recluses to occur over wide-ranging areas of the United States; and 2) brown recluses are frequently submitted from endemic states and almost never from nonendemic states, and therefore are virtually limited to their known distributions. This study corroborates opinions that diagnosis of brown recluse spider bites is best restricted to areas historically supporting proven, widespread populations of Loxosceles spiders.

  18. Reports of presumptive brown recluse spider bites reinforce improbable diagnosis in regions of North America where the spider is not endemic.

    Science.gov (United States)

    Vetter, Richard S; Bush, Sean P

    2002-08-15

    Envenomations by the brown recluse spider have been reported throughout North America, despite the fact that the spider's range is limited to the South and central Midwest of the United States. Several of these medical reports have originated from regions of nonendemicity where the spider has never or rarely been documented and brown recluse spider populations are unknown. In most of these reports, no spider is positively identified in association with the dermonecrotic wound, and diagnosis has been based on clinical examination findings. Considering the extreme rarity of brown recluse spiders in areas of nonendemicity, the diagnosis of a presumptive bite is a misdiagnosis that reinforces the assumption that brown recluse spiders are common local etiologic agents of necrosis. There are many medical conditions of diverse origin that have been misdiagnosed as brown recluse spider bites, some of which can be fatal or debilitating. Physicians' awareness of these conditions will increase diagnostic accuracy in areas of North America where bites from brown recluse spiders are improbable.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  20. Immunological Studies of Brown Recluse Spider Venom

    Science.gov (United States)

    Elgert, Klaus D.; Ross, Milton A.; Campbell, Benedict J.; Barrett, James T.

    1974-01-01

    Polyacrylamide gel electrophoresis of Loxosceles reclusa venom demonstrated that only one of seven or eight major (plus three or four minor) protein components caused necrosis in guinea pig skin. Sephadex gel filtration separated the venom into three major peaks, the second peak of which contained the dermonecrotic activity. Hyperimmunization of rabbits with increasing doses of venom from L. reclusa produced potent precipitating antisera, and the rabbits became resistant to lesion development. Ouchterlony-type immunodiffusion and immunoelectrophoretic studies revealed six to seven distinct precipitation lines, one of which stained intensely for esterase activity. Immunohistochemical techniques failed to detect any protease, lipase, catalase, acid phosphatase, alkaline phosphatase, or amylase activity in the venom. The spreading activity of recluse spider venom in guinea pig skin was inhibited as much as 71% by antivenom. Venom preincubated with antivenom was unable to incite lesions in guinea pig skin. Passive immunization of guinea pigs 18 h before an injection of venom conferred venom resistance upon the animals. Local injections of antivenom immediately after intradermal injections of venom markedly reduced the dermal lesion. Heparin reduced the local and systemic effects of venom when preincubated with whole venom or when administered systemically before an intradermal injection of venom. Treatment of whole venom with the chelating agent ethylenediaminetetraacetate did not inhibit its necrotic activity. Transfer studies from a 24-h lesion indicated that the necrotic activity was localized and remained active in tissue for at least 24 h but not for 5 days. No lesions developed when high concentrations of venom were intradermally injected into the skin of sacrificed guinea pigs, indicating that an interaction of body constituents and venom is essential for the development of a lesion. Images PMID:4140161

  1. Taxonomic revision of the spider family Penestomidae (Araneae, Entelegynae)

    NARCIS (Netherlands)

    Miller, J.A.; Griswold, C.E.; Haddad, C.R.

    2010-01-01

    Conflicting character evidence and a scarcity of male specimens has historically made placement of the spider subfamily Penestominae Simon problematic. The Penestominae was recently removed from the family Eresidae and promoted to family rank based on the results of a molecular phylogenetic study; a

  2. Mating duration and sperm precedence in the spider Linyphia triangularis

    DEFF Research Database (Denmark)

    Weldingh, Ditte L.; Toft, Søren; Larsen, Ole Næsbye

    2011-01-01

    , especially the males, are able to influence the outcome of mating for their own benefit. We studied the linyphiid spider Linyphia triangularis in which mating follows a strict sequence during which the male inducts two droplets of sperm and transfers them to the female. We performed sperm competition...

  3. LAMBRACHAEUS RAM/FER ALCOCK, A RARE SPIDER CRAB ...

    African Journals Online (AJOL)

    LAMBRACHAEUS RAM/FER ALCOCK, A RARE SPIDER CRAB FROM THE. EAST COAST OF SOUTHERN AFRICA (DECAPODA, BRACHYURA,. MAJIDAE). BRIAN KENS LEY. South African Museum. Cape Town. Accepted: May 1977. ABSTRACT. Lambrachaew rami/er Alcock, previously known only from a single record ...

  4. Spiders of the Vine Plants in Southern Moravia

    Directory of Open Access Journals (Sweden)

    Lucie Havlová

    2015-01-01

    Full Text Available Araneofauna of vineyards is relatively known in Central Europe but we have a lack of knowledge about araneofauna which occur directly on the vine plants. Our investigation was focused on spiders which live on vine plants, especially on the vine plants trunks. We investigated spiders in six vineyards in southern Moravia (Šatov, Mikulov, Popice, Morkůvky, Nosislav and Blučina. Vineyards were under different soil management, traps were placed on different parts of particular locality (terraced and plain and all localities were under integrated pest management. We employed two types of cardboard traps for spider collecting during whole vegetation season. Altogether, we collected 21 spider species which belong to seven families. The most important species was Marpissa nivoyi (Lucas, 1836, which is mentioned in the Red List as vulnerable (VU and Sibianor tantulus (Simon, 1868 which had unknown distribution in the Czech Republic. The other very interesting result is that the most common species is myrmecomorph Synageles venator (Lucas, 1836, which is scarcely recorded in such huge numbers as we documented in our study.

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

    Science.gov (United States)

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

  6. Ballooning behavior in the golden orbweb spider Nephilapilipes (Araneae: Nephilidae

    Directory of Open Access Journals (Sweden)

    Vanessa M.J. Lee

    2015-01-01

    Full Text Available Ballooning, a mode of aerial dispersal in spiders, is an innate behavior that requires appropriate physiological and meteorological conditions. Although only rarely reported in the golden orbweb spiders, family Nephilidae, the large geographic distributions of most nephilids—in particular of Nephila species—would imply that these spiders likely routinely disperse by ballooning in spite of giant female sizes. Here we study ballooning behavior in the golden orbweb spider Nephila pilipes (Fabricius, 1793. Specifically, we test for the propensity of spiderlings to deploy ballooning as a dispersal mechanism. We subjected a total of 59 first-instar spiderlings to a wind experiment at two wind speeds (2.17 ± 0.02 m s-1 and 3.17 ± 0.02 m s-1 under laboratory conditions. Under an average wind speed of 3.17 m s-1, none of the spiderlings exhibited pre-ballooning or ballooning behavior. However, at an average wind speed of 2.17 m s-1, 53 (89.8% spiderlings showed pre-ballooning behavior, and 17 (32.1% of the pre-ballooners ultimately ballooned. Our results concur with prior reports on spiderlings of other families that pre-ballooning behavior is a requirement for ballooning to occur. Furthermore, although we cannot rule out other dispersal mechanisms such as synanthropic spread, our findings suggest that the widespread N. pilipes uses ballooning to colonize remote oceanic islands.

  7. Food caching in orb-web spiders (Araneae: Araneoidea)

    Science.gov (United States)

    Champion de Crespigny, Fleur E.; Herberstein, Marie E.; Elgar, Mark A.

    2001-01-01

    Caching or storing surplus prey may reduce the risk of starvation during periods of food deprivation. While this behaviour occurs in a variety of birds and mammals, it is infrequent among invertebrates. However, golden orb-web spiders, Nephila edulis, incorporate a prey cache in their relatively permanent web, which they feed on during periods of food shortage. Heavier spiders significantly reduced weight loss if they were able to access a cache, but lost weight if the cache was removed. The presence or absence of stored prey had no effect on the weight loss of lighter spiders. Furthermore, N. edulis always attacked new prey, irrespective of the number of unprocessed prey in the web. In contrast, females of Argiope keyserlingi, who build a new web every day and do not cache prey, attacked fewer new prey items if some had already been caught. Thus, a necessary pre-adaptation to the evolution of prey caching in orb-web spiders may be a durable or permanent web, such as that constructed by Nephila.

  8. Female mating strategy during precopulatory mate guarding in spider mites

    NARCIS (Netherlands)

    Oku, K.

    2009-01-01

    In some taxa, females choose their mates indirectly by using male combat. In the Kanzawa spider mite, Tetranychus kanzawai, adult males guard prereproductive quiescent females. In a dual choice experiment, more males first approached females already guarded by a conspecific male than approached

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

    Science.gov (United States)

    Daniel T. Jennings; Frank Jr. Graham

    2007-01-01

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

  10. Infrared and Raman Study of the Recluse Spider Silk

    Science.gov (United States)

    Wang, S. L.; Wang, Qijue; Xing, Zhen; Schniepp, H. C.; Qazilbash, M. M.

    Spider silk exhibits remarkable mechanical properties, such as high tensile strength and toughness. We want to gain insight into the composition and structure of spider silk to discover the origin of these properties. We are especially interested in the organization of the crystalline beta sheets that are expected to contribute to the high strength of the silk from the recluse spider, Loxosceles laeta. The recluse spider produces a silk that has a unique geometry amongst arachnids. We measure the silk's optical properties, particularly the infrared-active and Raman-active vibrations. Broadband infrared transmission spectra were collected in the spectral range between 600 cm-1 and 4000 cm-1, with light polarized parallel and perpendicular to the long axis of the silk. Raman micro-spectroscopy was performed in the spectral range 500 cm-1 and 4000 cm- 1 with a 514 nm laser. The infrared and Raman vibrational modes are fit with Lorentzian and pseudo-Voigt functions. The vibrational modes are assigned to specific structures and electronic bonds in the silk. This work was supported by NASA/ Virginia Space Grant Consortium.

  11. 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

  12. Spider dystrophy as an ocular manifestation of myotonic dystrophy.

    Science.gov (United States)

    Louprasong, Amber C; Light, Dennis J; Diller, Rebecca S

    2010-04-01

    Myotonic dystrophy is the most common adult-onset muscular dystrophy. It is an autosomal dominant inherited neuromuscular disease that is characterized by myotonia, muscle weakness, and atrophy. It affects multiple systems including skeletal muscular, gastrointestinal, cardiac, respiratory, central nervous, endocrine, and ocular. Ocular manifestations of myotonic dystrophy include cataract, ocular muscle changes, hypotony, and retinal pigmentary changes in the periphery or in the macula (known as pigment pattern dystrophy). This report presents and discusses the case of a pigmented pattern dystrophy known as spider dystrophy as an ocular manifestation of myotonic dystrophy. A 44-year-old man with myotonic dystrophy presented to the eye clinic for routine examination. Ocular history included previous bilateral cataract surgery and mild bilateral ptosis for the last "few years." Dilated fundus examination was remarkable for bilateral macular pigmentary changes in an irregular "spider"-shaped pattern. The patient was asymptomatic without decrease in vision or Amsler grid defects. Optical coherence tomography was normal. A retinal consult concurred with the diagnosis of spider dystrophy. Photo documentation was obtained, and the patient is being monitored annually. Pigmented pattern dystrophies, including spider dystrophy, have been associated with myotonic dystrophy. They are set apart from other retinal dystrophies because they rarely affect visual acuity, and the majority of patients are asymptomatic. Progression may lead to reduced vision and in rare cases choroidal neovascularization. Annual dilated examinations, photo documentation, optical coherence tomography, and home Amsler grid monitoring are recommended for follow-up care. Published by Elsevier Inc.

  13. ArachnoServer: a database of protein toxins from spiders

    Directory of Open Access Journals (Sweden)

    Kaas Quentin

    2009-08-01

    Full Text Available 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 the largest pool of toxic peptides. However, at present, there are no databases dedicated to spider toxins and hence it is difficult to realise their full potential as drugs, insecticides, and pharmacological probes. Description We have developed ArachnoServer, a manually curated database that provides detailed information about proteinaceous toxins from spiders. Key features of ArachnoServer include a new molecular target ontology designed especially for venom toxins, the most up-to-date taxonomic information available, and a powerful advanced search interface. Toxin information can be browsed through dynamic trees, and each toxin has a dedicated page summarising all available information about its sequence, structure, and biological activity. ArachnoServer currently manages 567 protein sequences, 334 nucleic acid sequences, and 51 protein structures. Conclusion ArachnoServer provides a single source of high-quality information about proteinaceous spider toxins that will be an invaluable resource for pharmacologists, neuroscientists, toxinologists, medicinal chemists, ion channel scientists, clinicians, and structural biologists. ArachnoServer is available online at http://www.arachnoserver.org.

  14. Inactivation of complement by Loxosceles reclusa spider venom.

    Science.gov (United States)

    Gebel, H M; Finke, J H; Elgert, K D; Cambell, B J; Barrett, J T

    1979-07-01

    Zymosan depletion of serum complement in guinea pigs rendered them highly resistant to lesion by Loxosceles reclusa spider venom. Guinea pigs deficient in C4 of the complement system are as sensitive to the venom as normal guinea pigs. The injection of 35 micrograms of whole recluse venom intradermally into guinea pigs lowered their complement level by 35.7%. Brown recluse spider venom in concentrations as slight as 0.02 micrograms protein/ml can totally inactivate one CH50 of guinea pig complement in vitro. Bee, scorpion, and other spider venoms had no influence on the hemolytic titer of complement. Fractionation of recluse spider venom by Sephadex G-200 filtration separated the complement-inactivating property of the venom into three major regions which could be distinguished on the basis of heat stability as well as size. None was neutralized by antivenom. Polyacrylamide gel electrophoresis of venom resolved the complement inactivators into five fractions. Complement inactivated by whole venom or the Sephadex fractions could be restored to hemolytic activity by supplements of fresh serum but not by heat-inactivated serum, pure C3, pure C5, or C3 and C5 in combination.

  15. Incidense of spider mites in South Texas cotton fields

    Science.gov (United States)

    The incidence of spider mites was evaluated· in four locations of south Texas between Progreso (Hidalgo Co.) to Bishop (Nueces Co.). This is an area with a south to north transect of 125 miles from south Progreso to north Bishop (respectively).The other two intermediate sampled locations were Harlin...

  16. 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.

  17. Cardinium symbionts cause cytoplasmic incompatibility in spider mites.

    Science.gov (United States)

    Gotoh, T; Noda, H; Ito, S

    2007-01-01

    Intracellular symbiotic bacteria belonging to the Cytophaga-Flavobacterium-Bacteroides lineage have recently been described and are widely distributed in arthropod species. The newly discovered bacteria, named Cardinium sp, cause the expression of various reproductive alterations in their arthropod hosts, including cytoplasmic incompatibility (CI), induction of parthenogenesis and feminization of genetic males. We detected 16S ribosomal DNA sequences similar to those of Cardinium from seven populations of five spider mite species, suggesting a broad distribution of infection of Cardinium in spider mites. To clarify the effect of Cardinium on the reproductive traits of the infected spider mites, infected mites were crossed with uninfected mites for each population. In one of the populations, Eotetranychus suginamensis, CI was induced when infected males were crossed with uninfected females. The other six populations of four species showed no reproductive abnormalities in the F(1) generation, but the possibility of CI effects in the F(2) generation remains to be tested. One species of spider mite, Tetranychus pueraricola, harbored both Cardinium and Wolbachia, but these symbionts seemed to have no effect on the reproduction of the host, even when the host was infected independently with each symbiont.

  18. Spiders do not escape reproductive manipulations by Wolbachia.

    Science.gov (United States)

    Vanthournout, Bram; Swaegers, Janne; Hendrickx, Frederik

    2011-01-14

    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. 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. 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.

  19. The Spider Assemblage of Olive Groves Under Three Management Systems.

    Science.gov (United States)

    Cárdenas, Manuel; Pascual, Felipe; Campos, Mercedes; Pekár, Stano

    2015-06-01

    Olives, Olea europaea L., are one of the most important crops in Spain. They are currently produced under three management systems that involve different aspects of soil and pest management, productivity, and crop economy: organic, (integrated pest management-IPM), and conventional. Here, we studied how these systems affect the spiders, the natural enemies of olive grove pests, and performed a detailed analysis of their assemblage. The study was performed during one season in 18 olive groves in Andalusia, Spain, and included both ground-dwelling and canopy species. We found that the organic system supported a significantly higher level of abundance and diversity of canopy spiders than the IPM and conventional systems. Plowing had a negative effect on spider abundance and diversity. However, the presence of hedge vegetation had a positive effect on the spiders. The practices affected the guild structure differently, with some guilds supported by organic and others by IPM. It is suggested that sustainability (in terms of pest control) in olive grove agroecosystems may be obtained by maintaining hedge vegetation regardless of the management system. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Field performance of spider plant ( Cleome gynandra l) under ...

    African Journals Online (AJOL)

    Midlands province of Zimbabwe, to determine the effect of planting date and fertilizer types in enhancing the productivity of spider plant, an indigenous leafy vegetable. The experimental design was a split- plot arranged in a randomized complete block design (RCBD) with three blocks. The planting date was the main plot ...

  1. Characteristics of the first recorded spider (Arthropoda: Arachnida fauna from Sheringal, Khyber Pakhtunkhwa, Pakistan

    Directory of Open Access Journals (Sweden)

    Farzana Khan Perveen

    2015-12-01

    Full Text Available The spiders (order: Aranae are an important environmental indicator and play a significant role as predators in biological control of the most of the key insect pests. The present study was conducted to establish the characteristics of the first recorded spider fauna from Sheringal, Dir Upper (DU, Khyber Pakhtunkhwa (KP, Pakistan during June 2013-July 2014. Their 10 species belong to 7 families, and 10 genera (nt=123: total; ni=77: identified; nui=46: unidentified were recorded in the 6 quadrates, i.e., Daramdala, Doki, Guryaal, Samang, Shahoor and Sia-Sheringal of Sheringal. The largest family was Lycosidae (wolf spiders with respect to size and numbers of specimens collected (n=20, which contained Arctosa littorali Simon, 1897; Hippasa partita Takidar, 1970; Pardosa distincta Backwall, 1867, while the smallest family was Gnphosidae (ground spiders (n=3 with Gnaphosa eucalyptus Ghafoor and Beg, 2002; while other families Sparassidae (huntsman spiders (n=19 Halconia insignis Thorell, 1836, and Isopeda tuhogniga Barrion and Litsinger, 1995, Opilionidae (harvestmen spiders (n=12 Hadrobunus grandis Sundevall, 1833; Pholcidae (cellar spider (n=10 have Crossopriza lyoni Blackwall, 1867; Hersiliidae (two-tailed spiders (n=6 is having Harsilia savignyi Lucas, 1836; (n=5 with Araneus diadematus Clerck, 1757 were recorded. It was concluded that 50% of the spiders collected from the study area were venomous. A detail study is required for further exploration of spider fauna of Sheringal, KP, Pakistan with special reference to their taxonomical, physiological and ecological characteristics.

  2. 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.

  3. Predation on amphibians by spiders (Arachnida, Araneae in the Neotropical region

    Directory of Open Access Journals (Sweden)

    Marcelo Menin

    2005-10-01

    Full Text Available Herein, we report observations about spider predation on anurans (adults and juveniles in Central Amazonia and a literature review of spiders preying on amphibians in the Neotropical zoogeographic realm. We conducted field observations in Reserva Florestal Adolpho Ducke, Manaus, AM, and observed eight predation events on Bufonidae, Dendrobatidae, Hylidae, and Leptodactylidae frogs. The predators belong to the spider families Ctenidae, Pisauridae and Theraphosidae. Besides the families of spiders found in this study, two others – Lycosidae and Sparissidae - were found in literature. Frogs from families Centrolenidae and Microhylidae, and a caecilian(Gymnophiona, Caeciliidae were found in literature also. There is a significant correlation between the length of the anuran (snout-vent length and the length of spiders (cephalotorax and abdomen length. The size of the spider is similar or slightly lesser than the anuran prey. In general, the spiders preyed on adult and juvenile frogsin the breeding season. Spiders are opportunistic predators and prey on small frogs. Theraphosidae prey upon sub adults of large anurans and caecilians. As spiders can reach high densities on the forest floor - especially species of the genera Ctenus and Ancylometes - this interaction may be ecologically important for breeding anurans.Our reports and literature data provide evidence that spiders commonly prey on amphibians in Neotropic, but the impact of predation on populations of amphibians is unknown.

  4. Evaluating Stem Cell Response to a Spider Silk Scaffold

    Science.gov (United States)

    Hafner, Katherine Lee

    Micropatterning on a surface using fibers, channels, and troughs, can act as an effective means of inducing cell attachment and alignment. These morphological and pattern changes as a response to physical cues can impact the potential that a cell has to differentiate into a different cell line. This thesis evaluated the response of human dental pulp stem cells (DPSCs), and other cell types, to spider dragline silk fibers, a potential scaffold material for tissue regeneration, and further observed the effects of morphology, orientation, and composition of silk on the adherence of cells. Several cell lines were studied in this thesis, including adipose derived stem cells (ADSCs), osteoblasts (7F2s), and fibroblasts (3T3s), but DPSCs were the main cell type of interest. This is due to the fact that DPSCs are a proposed source of stem cells for nerve regeneration based on their close embryonic origin to neurons and the ease with which DPSCs can be obtained from a donor. The cells' morphologies and spread patterns were characterized after they were plated onto Nephila clavipes dragline fibers in media. The inclusion of 3T3s and 7F2s in this study allowed for both direct comparisons to prior published work and a qualitative comparison to the morphology of the DPSCs. After twelve days, the DPSCs exhibited greater relative alignment and adherence to the spider dragline fibers than the 3T3s and 7F2s when silk was wrapped in an aligned orientation rather than a random orientation. The impact of a common sterilization method (ultraviolet light) on the spider dragline fiber surface and subsequent cell response to this modified surface was also characterized. Exposure of the silk to ultraviolet light did not have a measureable effect on cell alignment, but it did eliminate bacterial growth and changed fiber surface roughness. Spiders' exposure to stressful environments did not have an effect on silk to impair cell alignment or adhesion, and synthetic recombinant protein silk

  5. Global Patterns of Guild Composition and Functional Diversity of Spiders

    Science.gov (United States)

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

    2011-01-01

    The objectives of this work are: (1) to define spider guilds for all extant families worldwide; (2) test if guilds defined at family level are good surrogates of species guilds; (3) compare the taxonomic and guild composition of spider assemblages from different parts of the world; (4) compare the taxonomic and functional diversity of spider assemblages and; (5) relate functional diversity with habitat structure. Data on foraging strategy, prey range, vertical stratification and circadian activity was collected for 108 families. Spider guilds were defined by hierarchical clustering. We searched for inconsistencies between family guild placement and the known guild of each species. Richness and abundance per guild before and after correcting guild placement were compared, as were the proportions of each guild and family between all possible pairs of sites. Functional diversity per site was calculated based on hierarchical clustering. Eight guilds were discriminated: (1) sensing, (2) sheet, (3) space, and (4) orb web weavers; (5) specialists; (6) ambush, (7) ground, and (8) other hunters. Sixteen percent of the species richness corresponding to 11% of all captured individuals was incorrectly attributed to a guild by family surrogacy; however, the correlation of uncorrected vs. corrected guilds was invariably high. The correlation of guild richness or abundances was generally higher than the correlation of family richness or abundances. Functional diversity was not always higher in the tropics than in temperate regions. Families may potentially serve as ecological surrogates for species. Different families may present similar roles in the ecosystems, with replacement of some taxa by other within the same guild. Spiders in tropical regions seem to have higher redundancy of functional roles and/or finer resource partitioning than in temperate regions. Although species and family diversity were higher in the tropics, functional diversity seems to be also influenced by

  6. Synthetic Spider Silk Production on a Laboratory Scale

    Science.gov (United States)

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

    2012-01-01

    As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation biomaterials with high performance properties. The development of these new structural materials must be rapid, cost-efficient and involve processing methodologies and products that are environmentally friendly and sustainable. Spiders spin a multitude of different fiber types with diverse mechanical properties, offering a rich source of next generation engineering materials for biomimicry that rival the best manmade and natural materials. Since the collection of large quantities of natural spider silk is impractical, synthetic silk production has the ability to provide scientists with access to an unlimited supply of threads. Therefore, if the spinning process can be streamlined and perfected, artificial spider fibers have the potential use for a broad range of applications ranging from body armor, surgical sutures, ropes and cables, tires, strings for musical instruments, and composites for aviation and aerospace technology. In order to advance the synthetic silk production process and to yield fibers that display low variance in their material properties from spin to spin, we developed a wet-spinning protocol that integrates expression of recombinant spider silk proteins in bacteria, purification and concentration of the proteins, followed by fiber extrusion and a mechanical post-spin treatment. This is the first visual representation that reveals a step-by-step process to spin and analyze artificial silk fibers on a laboratory scale. It also provides details to minimize the introduction of variability among fibers spun from the same spinning dope. Collectively, these methods will propel the process of artificial silk production, leading to higher quality fibers that surpass natural spider silks. PMID:22847722

  7. Synthetic spider silk production on a laboratory scale.

    Science.gov (United States)

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

    2012-07-18

    As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation biomaterials with high performance properties. The development of these new structural materials must be rapid, cost-efficient and involve processing methodologies and products that are environmentally friendly and sustainable. Spiders spin a multitude of different fiber types with diverse mechanical properties, offering a rich source of next generation engineering materials for biomimicry that rival the best manmade and natural materials. Since the collection of large quantities of natural spider silk is impractical, synthetic silk production has the ability to provide scientists with access to an unlimited supply of threads. Therefore, if the spinning process can be streamlined and perfected, artificial spider fibers have the potential use for a broad range of applications ranging from body armor, surgical sutures, ropes and cables, tires, strings for musical instruments, and composites for aviation and aerospace technology. In order to advance the synthetic silk production process and to yield fibers that display low variance in their material properties from spin to spin, we developed a wet-spinning protocol that integrates expression of recombinant spider silk proteins in bacteria, purification and concentration of the proteins, followed by fiber extrusion and a mechanical post-spin treatment. This is the first visual representation that reveals a step-by-step process to spin and analyze artificial silk fibers on a laboratory scale. It also provides details to minimize the introduction of variability among fibers spun from the same spinning dope. Collectively, these methods will propel the process of artificial silk production, leading to higher quality fibers that surpass natural spider silks.

  8. Rapid visuomotor processing of phobic images in spider- and snake-fearful participants.

    Science.gov (United States)

    Haberkamp, Anke; Schmidt, Filipp; Schmidt, Thomas

    2013-10-01

    This study investigates enhanced visuomotor processing of phobic compared to fear-relevant and neutral stimuli. We used a response priming design to measure rapid, automatic motor activation by natural images (spiders, snakes, mushrooms, and flowers) in spider-fearful, snake-fearful, and control participants. We found strong priming effects in all tasks and conditions; however, results showed marked differences between groups. Most importantly, in the group of spider-fearful individuals, spider pictures had a strong and specific influence on even the fastest motor responses: Phobic primes entailed the largest priming effects, and phobic targets accelerated responses, both effects indicating speeded response activation by phobic images. In snake-fearful participants, this processing enhancement for phobic material was less pronounced and extended to both snake and spider images. We conclude that spider phobia leads to enhanced processing capacity for phobic images. We argue that this is enabled by long-term perceptual learning processes. © 2013.

  9. Evolutionary morphology of the hemolymph vascular system of basal araneomorph spiders (Araneae: Araneomorphae).

    Science.gov (United States)

    Huckstorf, Katarina; Michalik, Peter; Ramírez, Martín; Wirkner, Christian S

    2015-11-01

    The superfamily Austrochiloidea (Austrochilidae and Gradungulidae) take a pivotal position in araneomorph spider phylogeny. In this discussion crevice weaver spiders (Filistatidae) are of equal interest. Especially data from these phylogenetically uncertain yet basal off branching groups can enlighten our understanding on the evolution of organ systems. In the course of a survey on the evolutionary morphology of the circulatory system in spiders we therefore investigated the hemolymph vascular system in two austrochiloid and one filistatid species. Additionally some data on a hypochilid and a gradungulid species are included. Using up-to-date morphological methods, the vascular systems in these spiders are visualized three dimensionally. Ground pattern features of the circulatory systems in austrochiloid spiders are presented and the data discussed along recent lines of phylogenetic hypotheses. Special topics highlighted are the intraspecific variability of the origins of some prosomal arteries and the evolutionary correlation of respiratory and circulatory systems in spiders. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Ontogenesis, gender, and molting influence the venom yield in the spider Coremiocnemis tropix (Araneae, Theraphosidae)

    OpenAIRE

    Herzig, Volker

    2010-01-01

    The demand for spider venom increases along with the growing popularity of venoms-based research. A deeper understanding of factors that influence the venom yield in spiders would therefore be of interest to both commercial venom suppliers and research facilities. The present study addresses the influence of several factors on the venom yield by systematically analyzing the data obtained from 1773 electrical milkings of the Australian theraphosid spider Coremiocnemis tropix. Gender and ontoge...

  11. 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.

  12. High school students? attitudes towards spiders: A cross-cultural comparison

    OpenAIRE

    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...

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

    OpenAIRE

    Soler, J. D.; Ade, P. A. R.; 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, Jeffrey P.; Fissel, L.M; Fraisse, A. A.

    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 t...

  14. Spider Silk: From Protein-Rich Gland Fluids to Diverse Biopolymer Fibers

    Science.gov (United States)

    2016-01-06

    Ala-rich regions in Nephila clavipes dragline (Biomacromolecules 2015, 16, 852). In addition, we successfully developed an in vitro solid-state NMR...producing process in vivo. We successfully imaged the major ampullate silk producing glands of a Nephila clavipes (Golden Orb Weaver) spider and...our 2D 2H-13C HETCOR MAS NMR experiments to investigate the Ala-rich regions of spider dragline silk from Nephila clavipes spiders. 2D 2H-13C

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

    OpenAIRE

    Eisner, T; Eisner, M; Deyrup, M

    1991-01-01

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

  16. Arachnids misidentified as brown recluse spiders by medical personnel and other authorities in North America.

    Science.gov (United States)

    Vetter, Richard S

    2009-09-15

    Misidentification of harmless or nearly benign arachnids as Loxosceles spiders by medical personnel and other authorities proliferates misinformation in regard to alleged loxoscelism and leads to decreased health care. This is especially true in areas of North America where Loxosceles spiders are rare or non-existent. A diverse assemblage of such misidentified arachnids is presented here. It is hoped that authorities will honestly assess their arachnological limitations and, instead, seek qualified arachnologists for spider identifications.

  17. Evaluation of fixative solutions for ultrastructural analysis of brown spider Loxosceles intermedia (araneae: sicariidae) tissues

    OpenAIRE

    Costa-Ayub,C. L. S.; Faraco,C. D.; Freire,C. A.

    2006-01-01

    In view of the widely varying compositions of fixative solutions used for studying spiders, five different fixative formulas were tested for fixing male brown-spider (Loxosceles intermedia) gonad tissues. The brown spider represents a public health problem in Curitiba (Paraná State, Brazil). Morphological study of its gonads may aid in understanding the reproductive strategies of this species, and possibly in developing a reproduction control program. The fixatives tested contained glutaralde...

  18. Tracking a Medically Important Spider: Climate Change, Ecological Niche Modeling, and the Brown Recluse (Loxosceles reclusa)

    OpenAIRE

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

    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 ...

  19. 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.

  20. Spider Mites Web: : a database dedicated to the knowledge of an acarine pest family, the Tetranychidae

    OpenAIRE

    Migeon, Alain; Dorkeld, Franck

    2008-01-01

    Building databases to collect information regarding pest families is particularly useful for an overall knowledge of their biology. Spider Mites Web is dedicated to the Tetranychidae, a family including about 1,250 species, of which 100 are considered as pests. Spider Mites Web is an online database, free, regularly updated, and continuously improved. Built to provide information on all described spider mites worldwide, the database was originally developed from work initiated by J. Gutierrez...

  1. Isolation and characterization of nine polymorphic microsatellite markers for the deep-sea shrimp Nematocarcinus lanceopes (Crustacea: Decapoda: Caridea)

    Science.gov (United States)

    2013-01-01

    Background The shrimp Nematocarcinus lanceopes Bate, 1888 is found in the deep sea around Antarctica and sub-Antarctic islands. Previous studies on mitochondrial data and species distribution models provided evidence for a homogenous circum-Antarctic population of N. lanceopes. However, to analyze the fine-scale population genetic structure and to examine influences of abiotic environmental conditions on population composition and genetic diversity, a set of fast evolving nuclear microsatellite markers is required. Findings We report the isolation and characterization of nine polymorphic microsatellite markers from the Antarctic deep-sea shrimp species Nematocarcinus lanceopes (Crustacea: Decapoda: Caridea). Microsatellite markers were screened in 55 individuals from different locations around the Antarctic continent. All markers were polymorphic with 9 to 25 alleles per locus. The observed heterozygosity ranged from 0.545 to 0.927 and the expected heterozygosity from 0.549 to 0.934. Conclusions The reported markers provide a novel tool to study genetic structure and diversity in Nematocarcinus lanceopes populations in the Southern Ocean and monitor effects of ongoing climate change in the region on the populations inhabiting these. PMID:23448502

  2. Polarimetry from the stratosphere with SPIDER and BLASTPol

    Science.gov (United States)

    Shariff, Jamil Aly

    This thesis presents the hardware development and flight performance of two balloon-borne experiments. The SPIDER experiment is a millimetre-wavelength polarimeter designed to measure B-mode polarization in the Cosmic Microwave Background at degree scales. This pattern is the imprint of the primordial gravitational waves predicted to have been produced by inflation. The BLASTPol experiment is a submillimetre-wavelength polarimeter designed to measure the linearly-polarized emission from aligned dust grains in Galactic molecular clouds, inferring the directions of the magnetic fields there. One goal of this measurement is to understand the role of magnetic fields in the earliest stages of star formation. SPIDER had a Long-Duration Balloon flight around Antarctica in January 2015. BLASTPol had two such flights, in December 2010 and 2012. Analysis of SPIDER data is underway. Results of BLASTPol 2012 data analysis are presented herein. The design and performance of the SPIDER pointing control system is presented. A new pivot motor control mode was developed, in which the servo drive controlled motor velocity, not current. This mode enabled sinusoidal azimuth scans at a peak speed of 5 deg/s, with a peak acceleration of 0.5 deg·s-2, in flight. The pointing stability in flight was 1'' to 2'' RMS. A new elevation drive system was designed and built for SPIDER. The SPIDER observing strategy is presented. It enabled observation of a 10% patch of sky, avoiding the sun and Galactic plane, with uniform coverage in declination, and good cross-linking. A model of the BLASTPol 2012 PSF was developed, allowing centroiding, flat-fielding, and map deconvolution. The latter was attempted in Fourier space, and using the Lucy-Richardson method. A net linear polarization of the dust emission in the Carina Nebula was measured by BLASTPol. The mean fractional polarization is 6.75% +/- 0.015%, 6.84% v 0.016% and 7.06% v 0.019%, at 250, 350, and 500 microm respectively. A falling

  3. Jumping spiders (Salticidae) enhance the seed production of a plant with extrafloral nectaries.

    Science.gov (United States)

    Ruhren, Scott; Handel, Steven N

    1999-05-01

    Many plants secrete nectar from extrafloral nectaries (EFNs), specialized structures that usually attract ants which can act as plant defenders. We examined the nectar-mediated interactions between Chamaecrista nictitans (Caesalpineaceae) and jumping spiders (Araneae, Salticidae) for 2 years in old fields in New Jersey, USA. Previous research suggests that spiders are entirely carnivorous, yet jumping spiders (Eris sp. and Metaphidippus sp.) on C. nictitans collected nectar in addition to feeding on herbivores, ants, bees, and other spiders. In a controlled-environment experiment, when given a choice between C. nictitans with or without active EFNs, foraging spiders spent 86% of their time on plants with nectar. C. nictitans with resident jumping spiders did set significantly more seed than plants with no spiders, indicating a beneficial effect from these predators. However, the presence of jumping spiders did not decrease numbers of Sennius cruentatus (Bruchidae), a specialist seed predator of C. nictitans. Jumping spiders may provide additional, unexpected defense to plants possessing EFNs. Plants with EFNs may therefore have beneficial interactions with other arthropod predators in addition to nectar-collecting ants.

  4. Information processing biases in spider phobia: application of the Stroop and "White Noise" Paradigm.

    Science.gov (United States)

    Olatunji, Bunmi O; Sawchuk, Craig N; Lee, Thomas C; Lohr, Jeffrey M; Tolin, David F

    2008-06-01

    The present study examines attentional and implicit memory biases in spider phobic and nonphobic participants. The results showed that spider phobics demonstrated increased interference for neutral, negative, and spider-relevant words on a computerized Stroop task. However, no group differences emerged when adjusting for differences in color-naming speed. Prior exposure to a dead spider did result in higher overall Stroop interference in spider phobics and this appeared to be mostly pronounced for spider-relevant words. Implicit memory bias for threat was examined with a noise judgment task. Participants first heard neutral and spider-relevant sentences and implicit memory for these sentences was evaluated by having participants rate the volume of noise accompanying the presentation of old sentences intermixed with new sentences. An implicit memory bias is indicated if participants rate noise accompanying old sentences as less loud than noise accompanying new sentences. No evidence was found for an implicit memory bias in spider phobics. These findings are discussed in relation to the role of information processing biases in spider phobia.

  5. Body burdens of metals in spiders from the Lidice coal dump near Ostrava (Czech Republic)

    Energy Technology Data Exchange (ETDEWEB)

    Wilczek, G.; Babczynska, A.; Majkus, Z. [Silesian University, Katowice (Poland)

    2005-09-01

    Spiders' feeding behaviour and external digestion expose them to man-made pollutants, especially those easily transferred along the food chain. The problem for this study was whether the levels of heavy metals in selected species of spiders from the Lidice coal dump reflect adaptation to environmental pollutants. We used flameless and flame AAS to measure the whole-body concentrations of Cd, Pb, Cu, Zn, Fe, Ni and Mg in male and female spiders differing in their hunting strategies, type of web construction, prey, and taxonomic position (Araneidae, Agelenidae, Linyphiidae, Theridiidae, Tetragnathidae, Lycosidae, Salticidae, Pisauridae, Clubionidae, Philodromidae). The levels of metals found in the spiders were species-dependent, indicating differences related to the hunting strategy and type of prey. Accumulation of Pb, Cu and Zn was always higher in ground spiders than in web-constructing species. Sheet-web spiders Linyphia triangularis and wandering spiders Clubiona lutescens had the lowest Cd, Mg and Cu content of all the studied species. Web-building spiders of the Tetragnathidae family showed the highest Cd, Cu and Pb content, even in species with feeding behaviour similar to spiders of other families. There were no interspecific differences in accumulation only for Fe and Mg. The concentrations of Cd, Ni and Pb were lower in females than in males, irrespective of their taxonomic position and the intensity of their hunting activity. This may suggest that females have better metal-excretion ability than males.

  6. Trap and soil monolith sampled edaphic spiders (arachnida: araneae) in Araucaria angustifolia forest

    National Research Council Canada - National Science Library

    Baretta, Dilmar; Brescovit, Antonio Domingos; Knysak, Irene; Cardoso, Elke Jurandy Bran Nogueira

    2007-01-01

    Forests with Araucaria angustifolia (Bert.) O. Kuntze trees are endangered in Brazil, and information on the diversity of soil spider families associated to these environments is practically inexistent...

  7. Direction of stimulus movement alters fear-linked individual differences in attentional vigilance to spider stimuli.

    Science.gov (United States)

    Basanovic, Julian; Dean, Laurence; Riskind, John H; MacLeod, Colin

    2017-12-01

    Researchers have proposed that high spider-fearful individuals are characterised by heightened attentional vigilance to spider stimuli, as compared to low spider-fearful individuals. However, these findings have arisen from methodologies that have uniformly employed only static stimuli. Such findings do not inform upon the patterns of fear-linked attentional selectivity that occur in the face of moving feared stimuli. Hence, the present study developed a novel methodology designed to examine the influence of stimulus movement on attentional vigilance to spider and non-spider stimuli. Eighty participants who varied in level of spider-fear completed an attentional-probe task that presented stimuli under two conditions. One condition presented stimuli that displayed an approaching movement, while the other condition presented stimuli that displayed a receding movement. Fear-linked heightened attentional vigilance was observed exclusively under the latter condition. These findings suggest that fear-linked attentional vigilance to spider stimuli does not represent a uniform characteristic of heightened spider-fear, but rather is influenced by stimulus context. The means by which these findings inform understanding of attentional mechanisms that characterise heightened spider-fear, and avenues for future research, are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Functional Group of Spiders in Cultivated Landscape Dominated by Paddy Fields in West Java, Indonesia

    Directory of Open Access Journals (Sweden)

    I WAYAN SUANA

    2009-03-01

    Full Text Available Distribution of spiders in all colonized environments is limited by biotic and abiotic factors requiring adaptations with respect to, for example microhabitat choice and hunting behavior. These two factors were frequently used to group spiders into functional groups. In this study our objectives were to (i group of genera of spiders into functional group based on their microhabitat specificity, hunting behavior, and daily activity; and (ii compare the number and composition of functional group of spider at each habitat type and period of paddy growth. The study was conducted at a landscape dominated by paddy fields in Cianjur Watershed for a period of 9 months. Four different habitat types (paddy, vegetable, non-crop, and mixed garden, were sampled using five trapping techniques (pitfall traps, farmcop suction, sweep netting, yellow-pan traps, and sticky traps. The Unweighted Pair-Group Average and the Euclidean Distances were used to generate dendrogram of functional group of spider. We found 14 functional groups of spider at genus level. The number of functional group of spider at four habitat types was differing, but the composition was similar, because all habitats were closed to each other. Habitat structure diversity and disturbance level influenced the number of functional group of spider. Different architecture of vegetation and availability of differ prey during paddy growth, causing the composition of functional group of spider in each period of paddy growth was changed, although its number was unchanged.

  9. Processing of recombinant spider silk proteins into tailor-made materials for biomaterials applications.

    Science.gov (United States)

    Schacht, Kristin; Scheibel, Thomas

    2014-10-01

    Spider silk has extraordinary mechanical properties, is biocompatible and biodegradable, and therefore an ideal material for biomedical applications. However, a drawback for any application is the inhomogeneity of spider silk, as seen for other natural materials, as well as the low availability due to the cannibalism of most spiders. Recently, developed recombinant spider silk proteins ensure constant material properties, as well as scalable production, and further the processing into morphologies other than fibres. Biotechnology enables genetic modification, broadening the range of applications, such as implant coatings, scaffolds for tissue engineering, wound dressing devices as well as drug delivery systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Spiders do not evoke greater early posterior negativity in the event-related potential as snakes.

    Science.gov (United States)

    He, Hongshen; Kubo, Kenta; Kawai, Nobuyuki

    2014-09-10

    It has been long believed that both snakes and spiders are archetypal fear stimuli for humans. Furthermore, snakes have been assumed as stronger threat cues for nonhuman primates. However, it is still unclear whether spiders hold a special status in human perception. The current study explored to what extent spider pictures draw early visual attention [as assessed with early posterior negativity (EPN)] when compared with insects similar to spiders. To measure the EPN, participants watched a random rapid serial presentation of pictures, which consisted of two conditions: spider condition (spider, wasp, bumblebee, beetle) and snake condition (snake, bird). EPN amplitudes revealed no significant difference between spider, wasp, bumblebee, and beetle pictures, whereas EPN amplitudes were significantly larger for snake pictures relative to bird pictures. In addition, EPN amplitudes were significantly larger for snake pictures relative to spider pictures. These results suggest that the early visual attentional capture of animate objects is stronger for snakes, whereas spiders do not appear to hold special early attentional value.

  11. Australian Assassins, Part I: A review of the Assassin Spiders (Araneae, Archaeidae) of mid-eastern Australia

    National Research Council Canada - National Science Library

    Rix, Michael G; Harvey, Mark S

    2011-01-01

    The Assassin Spiders of the family Archaeidae are an ancient and iconic lineage of basal araneomorph spiders, characterised by a specialised araneophagic ecology and unique, 'pelican-like' cephalic morphology...

  12. Composition of the silk lipids of the spider Nephila clavipes.

    Science.gov (United States)

    Schulz, S

    2001-06-01

    A detailed analysis of the lipids of spider silk is given for the first time. Extracts of the silk from the golden orb weaver, Nephila clavipes, were studied by gas chromatography, mass spectrometry, and chemical derivatizations. The major group of the lipids consisted of methyl-branched 1-methoxyalkanes (methyl ethers) with up to four methyl groups in the chain (chain length between C28 and C34), which are unique to spiders. The position of the methyl branches was determined by conversion into cyanides, which allowed easy location of methyl branches. The second-largest group included alkanes with a wide structural variety; 2-methyl-branched, even-numbered hydrocarbons predominated. A general numerical method for the estimation of retention indices of alkanes and their derivatives is presented. Further components of the web included alkanols and alkanediols, fatty acids, and glyceryl ethers. Some comments on the biosynthesis of these compounds are also given.

  13. Mechanical Properties of Spider Dragline Silk: Humidity, Hysteresis, and Relaxation

    Science.gov (United States)

    Vehoff, T.; Glišović, A.; Schollmeyer, H.; Zippelius, A.; Salditt, T.

    2007-01-01

    Spider silk is well-known for its outstanding mechanical properties. However, there is a significant variation of these properties in literature and studies analyzing large numbers of silk samples to explain these variations are still lacking. To fill this gap, the following work examines the mechanical properties of major ampullate silk based on a large ensemble of threads from Nephila clavipes and Nephila senegalensis. In addition, the effect of relative humidity (RH) on the mechanical properties was quantified. The large effect of RH on the mechanical properties makes it plausible that the variation in the literature values can to a large extent be attributed to changes in RH. Spider silk's most remarkable property—its high tenacity—remains unchanged. In addition, this work also includes hysteresis as well as relaxation measurements. It is found that the relaxation process is well described by a stretched exponential decay. PMID:17766337

  14. A Spider That Lays Its Eggs in Rows

    Directory of Open Access Journals (Sweden)

    Robert L. Edwards

    2000-01-01

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

  15. Optics of the ultraviolet reflecting scales of a jumping spider

    Science.gov (United States)

    Land, Michael F; Horwood, Julia; Lim, Matthew L.M; Li, Daiqin

    2007-01-01

    The jumping spider Cosmophasis umbratica from Singapore is strongly sexually dimorphic. The males, but not the females, reflect ultraviolet as well as green–orange light. The scales responsible for this are composed of a chitin–air–chitin sandwich in which the chitin layers are three-quarters of a wavelength thick and the air gap a quarter wavelength (where λ=600 nm, the peak wavelength of the principal reflection maximum). It is shown that this configuration produces a second reflectance peak at approximately 385 nm, accounting for the observed reflection in the ultraviolet. Other scales have a similar thickness of chitin but lack the air gap and thus produce a dull purple reflection. This novel mechanism provides the spiders with two colour signals, both of which are important in mating displays. PMID:17456453

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

    Science.gov (United States)

    Doroshin, Anton V.

    2010-03-01

    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.

  17. A collection of spiders (Araneae in Albanian coastal areas

    Directory of Open Access Journals (Sweden)

    Vrenozi, Blerina

    2012-12-01

    Full Text Available The present study unites data from several excursions in typical Mediterranean lowland ecosystems in Albania during the years 2006 to 2009. Spiders from several different habitat types along the coast were analysed in six districts: Saranda, Fieri, Kavaja, Durrësi, Tirana and Lezha. In total 299 adult specimens were collected. They belong to 82 species, 60 genera and 22 families. Six species are new to the Albanian fauna: Aculepeira armida (Audouin, 1826, Zygiella x-notata (Clerck, 1757, Histopona torpida (C. L. Koch, 1837, Malthonica campestris (C. L. Koch, 1834, Pellenes tripunctatus (Walckenaer, 1802 and Pseudeuophrys erratica (Walckenaer, 1826. With respect to zoogeography, the spider fauna is mainly characterized by the presence of many Palaearctic species.

  18. Brown recluse spider envenomation: dermatologic application of hyperbaric oxygen therapy.

    Science.gov (United States)

    Tutrone, William D; Green, Kimberly M; Norris, Tom; Weinberg, Jeffrey M; Clarke, Dick

    2005-01-01

    Envenomation from the brown recluse (Loxosceles recluse) spider commonly proceed on one of three clinical pathways. The majority of bites (90%) result in nothing more than a local reaction. They are essentially self-limiting, require little if any attention, and resolve spontaneously. A great majority of the remaining bites will produce necrotic ulcerations of various sizes and dimensions, with systemic sequela ranging from fever to hemolysis and kidney failure. Finally, and in the most rare cases, the patient will succumb a fatal systemic reaction. Current therapeutic options for these wounds remain controversial and include the following: local care, corticosteroids, dapsone, and hyperbaric oxygen (HBO) therapy. This article will review the application of HBO therapy for patients who are envenomated by brown recluse spiders. Information for this manuscript was derived from multiple MEDLINE searches as well as searches of the National Baromedical Service's hyperbaric specialty literature collection.

  19. Trap design for the brown recluse spider, Loxosceles reclusa.

    Science.gov (United States)

    Parks, Jennifer; Stoecker, William V; Paige, Robert L

    2013-01-01

    While there are limited options for chemical-free Arachnid pest control, glue-traps are one suitable alternative to pesticides. The effectiveness of several three-dimensional glue-trap shapes for trapping the brown recluse spider, Loxosceles reclusa Gertsch and Mulaik (Araneae: Sicariidae), was investigated using four novel glue-trap shape designs, which were compared to an existing design currently on the market. These four novel and one standard shape designs were tested using pairwise comparisons. The most preferred trap design was a flat glue-trap with no covering. Although this type of trap was most efficient for capturing L. reclusa, it can pose risks in homes with children and pets for obvious reasons. Among the traps with coverings, the vertical strut trap was most preferred by the spiders, and should perhaps be the trap of choice for homeowners with children and pets.

  20.  “Spiders and Webs in American Literature”

    Directory of Open Access Journals (Sweden)

    Vincent Dussol

    2012-05-01

    Full Text Available From Jonathan Edwards to Jorie Graham, spiders are strikingly present in American literature. The purpose of this article is first to show how that theme may have become something of a national tradition as very different writers, all of them careful observers of aranae, answered one another through the years. It is very likely that the attention paid to spiders by American authors was increased by those Native American myths in which spiders are a central figure. More than occasionally, on the female side of the American counter-culture, especially among its feminist and lesbian exponents, simple activists and creative writers have harnessed the symbolic power invested in the spider by Native Americans.There may be deeper reasons accounting for American authors’ fascination with spiders. The country’s phobia of disunion is one; a nation of settlers’ acute consciousness of the precariousness of its occupation of the territory is another. In demonstrating outstanding skills for adjustment to unknown places, spiders epitomize a form of identity permanence. The predominantly positive character of spider symbols in American literature will occasionally be inverted. Following the national logic of checks and balances, any web covering the whole of the United States will tend to come under suspicion.This study ends with an inventory of cultural productions linked with spiders and webs and whose Americanness is yet to be clearly determined.De Jonathan Edwards à Jorie Graham, l’araignée apparaît dans un nombre frappant de textes littéraires américains. On a d’abord voulu tenter de montrer comment a pu se construire cette tradition thématique et faire la preuve que différents écrivains, réunis par un souci de l’observation, se sont répondus à travers elle. L’attention prêtée à l’araignée s’est certainement trouvée renforcée par les récits mythologiques des peuples premiers américains qui font de l’araignée une

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

    Science.gov (United States)

    Hormiga, Gustavo; Griswold, Charles E

    2014-01-01

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

  2. Web-mediated interspecific competition among spider mites.

    Science.gov (United States)

    Morimoto, K; Furuichi, H; Yano, S; Osakabe, M

    2006-06-01

    Some spider mites, such as Tetranychus spp. and Amphitetranychus spp., create complicated webs (CWs), whereas others, such as Panonychus spp., produce little webs (LWs). We verified whether interspecific competition occurred between CW and LW mites via habitat arrangement under laboratory conditions. The complicated webs produced by CW mites clearly inhibited juvenile development in LW mites, whereas there was no effect of LW mites on CW mites. In oviposition site choice tests, both CW and LW females preferred the lower surface of leaves to the upper surface. The preference of LW mites for the lower leaf surface, even in the presence of CW mite webs, suggests that the costs of amensalism are outweighed by the possible benefits, such as avoiding rain. These findings show that the shift in mite species composition from LW to CW mites can occur as a consequence of the interspecific association between spider mites via their webs, without pesticide applications or the presence of natural enemies.

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

    Science.gov (United States)

    Suzuki, Takeshi

    2012-10-26

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

  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. Animal behaviour: task differentiation by personality in spider groups.

    Science.gov (United States)

    Grinsted, Lena; Bacon, Jonathan P

    2014-08-18

    In social animals, group efficiency is often assumed to increase with task differentiation, but this requires that individuals are better than generalists at the task they specialize in. A new study finds that individual Anelosimus studiosus spiders do predominantly perform the task they excel at, in line with their individual personality type, when they are placed in groups. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. [Neurotoxic manifestations of black widow spider envenomation in paediatric patients].

    Science.gov (United States)

    Sotelo-Cruz, N; Gómez-Rivera, N

    2016-05-01

    Envenomation by black widow spiders manifests clinically with signs of neurotoxicity in paediatric patients. Identify typical neurological signs and symptoms in paediatric patients of different ages, and describe treatment and outcomes in a paediatric hospital in northwest Mexico. We reviewed 70 clinical records of patients hospitalised due to black widow spider bite between 1978 and 2014. We divided the total into 2 groups: Group 1, infants and preschool children; and Group 2, school-age children and adolescents. The demographic variables were age, sex, birthplace, place where envenomation occurred, body part(s) affected, degree of envenomation according to signs and symptoms, treatment, clinical outcome, and statistical differences. Boys accounted for 61.4% of all cases, and infants younger than one year old made up 14.2%. Most patients (70%) were bitten by the spider at home; the anatomical areas most frequently affected were the legs, neck, thorax, and abdomen. The neurological signs and symptoms displayed by Group 1 were irritability, constant crying, sialorrhoea, nausea, tachycardia, arrhythmias, fatigue when walking, agitation, muscle spasms paraesthesia, tetany, seizures, and nystagmus. Signs in Group 2 included localized pain, headache, sialorrhoea, paraesthesia, profuse sweating, anxiety, muscle weakness, muscle spasms, and fine tremor. The predominant autonomic sign in Group 1 was sialorrhoea (P<.0001) and in Group 2, paraesthesia (P<.0001). Patients who received Fab antivenom treatment displayed better outcomes and shorter hospital stays than those who did not. No deaths were reported. The neurological signs and symptoms caused by black widow spider bite are predominantly autonomic, and identifying them permits early diagnosis and more effective treatment. Copyright © 2015 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.

  7. On the diversity of some spiders (Aranea: Arachnida from Serbia

    Directory of Open Access Journals (Sweden)

    Ćurčić Božidar P.

    2003-01-01

    Full Text Available A total of 76 species from 16 families: Dysderidae (6, Theridiidae (3 Nesticidae (1, Linyphiidae (35, Tetragnathidae (1, Araneidae (1 Lycosidae (5, Agelenidae (3, Cybaeidae (1, Dictynidae (1, Amaurobiidae (5, Liocranidae (2, Clubionidae (3, Gnaphosidae (3, Thomisidae (3 and Salticidae (3 were established from 42 localities in Serbia. Ten species and three genera are new for the Serbian spider fauna. The most diverse is the family Linyphiidae, otherwise represented by 35 species.

  8. On the colours of spider orb-webs

    Energy Technology Data Exchange (ETDEWEB)

    Suhr, Wilfried; Schlichting, H Joachim, E-mail: wilfried.suhr@uni-muenster.de, E-mail: schlichting@uni-muenster.de [Institut fuer Didaktik der Physik, University of Muenster, 48149 Muenster (Germany)

    2011-03-15

    A sticky capture thread from the spiral element of spider orb-webs is formed of almost regularly spaced droplets that surround a supporting axial fibre. From the perspective of physical optics it represents a periodic linear array of scattering elements that acts as a diffraction grating. This is a novel aspect, which is of vital importance for the understanding of the overall scattering pattern. To demonstrate its significance, we present our experimental findings and compare them with results of a simplified model.

  9. 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.

  10. 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 Mountain s (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

  11. Individual personalities shape task differentiation in a social spider

    OpenAIRE

    Grinsted, Lena; Pruitt, Jonathan N.; Settepani, Virginia; Bilde, Trine

    2013-01-01

    Deciphering the mechanisms involved in shaping social structure is key to a deeper understanding of the evolutionary processes leading to sociality. Individual specialization within groups can increase colony efficiency and consequently productivity. Here, we test the hypothesis that within-group variation in individual personalities (i.e. boldness and aggression) can shape task differentiation. The social spider Stegodyphus sarasinorum (Eresidae) showed task differentiation (significant uneq...

  12. Trap Design for the Brown Recluse Spider, Loxosceles reclusa

    OpenAIRE

    Parks, Jennifer; Stoecker, William V.; Paige, Robert L.

    2013-01-01

    While there are limited options for chemical-free Arachnid pest control, glue-traps are one suitable alternative to pesticides. The effectiveness of several three-dimensional glue-trap shapes for trapping the brown recluse spider, Loxosceles reclusa Gertsch and Mulaik (Araneae: Sicariidae), was investigated using four novel glue-trap shape designs, which were compared to an existing design currently on the market. These four novel and one standard shape designs were tested using pairwise comp...

  13. A troglomorphic spider from Java (Araneae, Ctenidae, Amauropelma)

    Science.gov (United States)

    Miller, Jeremy; Rahmadi, Cahyo

    2012-01-01

    Abstract A new troglomorphic spider from caves in Central Java, Indonesia, is described and placed in the ctenid genus Amauropelma Raven, Stumkat & Gray, until now containing only species from Queensland, Australia. Only juveniles and mature females of the new species are known. We give our reasons for placing the new species in Amauropelma, discuss conflicting characters, and make predictions about the morphology of the as yet undiscovered male that will test our taxonomic hypothesis. The description includes DNA barcode sequence data. PMID:22303127

  14. A Reconsideration of the Classification of the Spider Infraorder Mygalomorphae (Arachnida: Araneae) Based on Three Nuclear Genes and Morphology

    OpenAIRE

    Bond, Jason E.; Hendrixson, Brent E.; Hamilton, Chris A.; Marshal Hedin

    2012-01-01

    BACKGROUND: The infraorder Mygalomorphae (i.e., trapdoor spiders, tarantulas, funnel web spiders, etc.) is one of three main lineages of spiders. Comprising 15 families, 325 genera, and over 2,600 species, the group is a diverse assemblage that has retained a number of features considered primitive for spiders. Despite an evolutionary history dating back to the lower Triassic, the group has received comparatively little attention with respect to its phylogeny and higher classification. The fe...

  15. A New Limit on CMB Circular Polarization from SPIDER

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, J.M.; et al.

    2017-04-01

    We present a new upper limit on CMB circular polarization from the 2015 flight of SPIDER, a balloon-borne telescope designed to search for $B$-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the non-zero circular-to-linear polarization coupling of the HWP polarization modulators, data from SPIDER's 2015 Antarctic flight provides a constraint on Stokes $V$ at 95 and 150 GHz from $33<\\ell<307$. No other limits exist over this full range of angular scales, and SPIDER improves upon the previous limit by several orders of magnitude, providing 95% C.L. constraints on $\\ell (\\ell+1)C_{\\ell}^{VV}/(2\\pi)$ ranging from 141 $\\mu K ^2$ to 203 $\\mu K ^2$ at 150 GHz for a thermal CMB spectrum. As linear CMB polarization experiments become increasingly sensitive, the techniques described in this paper can be applied to obtain stronger constraints on circular polarization.

  16. Evidence for antimicrobial activity associated with common house spider silk

    Directory of Open Access Journals (Sweden)

    Wright Simon

    2012-06-01

    Full Text Available Abstract Background Spider silk is one of the most versatile materials in nature with great strength and flexibility. Native and synthetically produced silk has been used in a wide range of applications including the construction of artificial tendons and as substrates for human cell growth. In the literature there are anecdotal reports that suggest that native spider silk may also have antimicrobial properties. Findings In this study we compared the growth of a Gram positive and a Gram negative bacterium in the presence and absence of silk produced by the common house spider Tegenaria domestica. We demonstrate that native web silk of Tegenaria domestica can inhibit the growth of the Gram positive bacterium, Bacillus subtilis. No significant inhibition of growth was detected against the Gram negative bacterium, Escherichia coli. The antimicrobial effect against B. subtilis appears to be short lived thus the active agent potentially acts in a bacteriostatic rather than bactericidal manner. Treatment of the silk with Proteinase K appears to reduce the ability to inhibit bacterial growth. This is consistent with the active agent including a protein element that is denatured or cleaved by treatment. Tegenaria silk does not appear to inhibit the growth of mammalian cells in vitro thus there is the potential for therapeutic applications.

  17. Epigeic spiders of the pastures of northern Wielkopolska

    Directory of Open Access Journals (Sweden)

    Woźny, Marek

    2000-10-01

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

  18. Management of brown recluse spider bites in primary care.

    Science.gov (United States)

    Mold, James W; Thompson, David M

    2004-01-01

    Treatment of brown recluse spider bites remains controversial; there are multiple options but little evidence of their effectiveness. Over a 5-year period, family physicians enrolled consecutive patients with suspected brown recluse spider bites. Usual care was provided based on physician preferences. Topical nitroglycerine patches and vitamin C tablets were provided at no cost for those who wished to use them. Baseline data were collected, and patients were followed-up weekly until healing occurred. Outcome measures included time to healing and occurrence of scarring. Regression methods were used to evaluate the impact of the 4 main treatment approaches (corticosteroids, dapsone, topical nitroglycerine, and high-dose vitamin C) after controlling for bite severity and other predictors. Two hundred and sixty-two patients were enrolled; outcomes were available for 189. The median healing time was 17 days. Only 21% had permanent scarring. One hundred seventy-four received a single treatment modality. Among this group, 12 different modalities were used. After controlling for other variables, predictors of more rapid healing included lower severity level, less erythema, and less necrosis at time of presentation, younger age, no diabetes, and earlier medical attention. Systemic corticosteroids and dapsone were associated with slower healing. Predictors of scarring were higher severity, presence of necrosis, and diabetes. Dapsone was associated with an increased probability of scarring. We found no evidence that commonly used treatment approaches reduced healing time or the likelihood of scarring in suspected brown recluse spider bites.

  19. Individual personalities shape task differentiation in a social spider.

    Science.gov (United States)

    Grinsted, Lena; Pruitt, Jonathan N; Settepani, Virginia; Bilde, Trine

    2013-09-22

    Deciphering the mechanisms involved in shaping social structure is key to a deeper understanding of the evolutionary processes leading to sociality. Individual specialization within groups can increase colony efficiency and consequently productivity. Here, we test the hypothesis that within-group variation in individual personalities (i.e. boldness and aggression) can shape task differentiation. The social spider Stegodyphus sarasinorum (Eresidae) showed task differentiation (significant unequal participation) in simulated prey capture events across 10-day behavioural assays in the field, independent of developmental stage (level of maturation), eliminating age polyethism. Participation in prey capture was positively associated with level of boldness but not with aggression. Body size positively correlated with being the first spider to emerge from the colony as a response to prey capture but not with being the first to attack, and dispersal distance from experimental colonies correlated with attacking but not with emerging. This suggests that different behavioural responses to prey capture result from a complex set of individual characteristics. Boldness and aggression correlated positively, but neither was associated with body size, developmental stage or dispersal distance. Hence, we show that personalities shape task differentiation in a social spider independent of age and maturation. Our results suggest that personality measures obtained in solitary, standardized laboratory settings can be reliable predictors of behaviour in a social context in the field. Given the wealth of organisms that show consistent individual behavioural differences, animal personality could play a role in social organization in a diversity of animals.

  20. Jewelled spiders manipulate colour-lure geometry to deceive prey.

    Science.gov (United States)

    White, Thomas E

    2017-03-01

    Selection is expected to favour the evolution of efficacy in visual communication. This extends to deceptive systems, and predicts functional links between the structure of visual signals and their behavioural presentation. Work to date has primarily focused on colour, however, thereby understating the multicomponent nature of visual signals. Here I examined the relationship between signal structure, presentation behaviour, and efficacy in the context of colour-based prey luring. I used the polymorphic orb-web spider Gasteracantha fornicata, whose yellow- or white-and-black striped dorsal colours have been broadly implicated in prey attraction. In a manipulative assay, I found that spiders actively control the orientation of their conspicuous banded signals in the web, with a distinct preference for near-diagonal bearings. Further field-based study identified a predictive relationship between pattern orientation and prey interception rates, with a local maximum at the spiders' preferred orientation. There were no morph-specific effects on capture success, either singularly or via an interaction with pattern orientation. These results reveal a dynamic element in a traditionally 'static' signalling context, and imply differential functions for chromatic and geometric signal components across visual contexts. More broadly, they underscore how multicomponent signal designs and display behaviours may coevolve to enhance efficacy in visual deception. © 2017 The Author(s).

  1. Optimal foraging, not biogenetic law, predicts spider orb web allometry

    Science.gov (United States)

    Gregorič, Matjaž; Kiesbüy, Heine C.; Quiñones Lebrón, Shakira G.; Rozman, Alenka; Agnarsson, Ingi; Kuntner, Matjaž

    2013-03-01

    The biogenetic law posits that the ontogeny of an organism recapitulates the pattern of evolutionary changes. Morphological evidence has offered some support for, but also considerable evidence against, the hypothesis. However, biogenetic law in behavior remains underexplored. As physical manifestation of behavior, spider webs offer an interesting model for the study of ontogenetic behavioral changes. In orb-weaving spiders, web symmetry often gets distorted through ontogeny, and these changes have been interpreted to reflect the biogenetic law. Here, we test the biogenetic law hypothesis against the alternative, the optimal foraging hypothesis, by studying the allometry in Leucauge venusta orb webs. These webs range in inclination from vertical through tilted to horizontal; biogenetic law predicts that allometry relates to ontogenetic stage, whereas optimal foraging predicts that allometry relates to gravity. Specifically, pronounced asymmetry should only be seen in vertical webs under optimal foraging theory. We show that, through ontogeny, vertical webs in L. venusta become more asymmetrical in contrast to tilted and horizontal webs. Biogenetic law thus cannot explain L. venusta web allometry, but our results instead support optimization of foraging area in response to spider size.

  2. Review of the Australian wolf spider genus Venator (Araneae, Lycosidae).

    Science.gov (United States)

    Framenau, Volker W

    2015-09-11

    Species of the Australian wolf spider genus Venator are reviewed including the type species, V. spenceri Hogg, 1900, from south-eastern Australia and V. immansuetus (Simon, 1909) comb. nov., a common species in south-west Western Australia. Venator marginatus Hogg, 1900 is only known from two female specimens and the genital morphology of this species does not conform to the diagnosis of genus as presented here. Therefore V. marginatus is considered incerta sedis. Venator includes medium-sized (9.0-22 mm body length) wolf spiders of overall brownish colouration, and with a black patch covering the anterior three quarters of the venter. They differ from all other wolf spiders in particular by genitalic characters, namely an elevated atrium of the female epigyne that forms a raised edged against the inverted T-shaped median septum. This edge often corresponds to a retrolateral incision on the tegular apophysis of the male pedipalp. The genus is mainly a representative of the Bassian fauna of the Australian continent where it occurs predominantly in dry sclerophyll forests.

  3. Diapause incidence in the two-spotted spider mite increases due to predator presence, not due to selective predation.

    NARCIS (Netherlands)

    Kroon, A.; Veenendaal, R.L.; Egas, C.J.M.; Bruin, J.; Sabelis, M.W.

    2005-01-01

    We recently reported evidence for increased diapause incidence in the spider mite Tetranychus urticae in the presence of the predatory mite Typhlodromus pyri. This effect may arise from (1) selective predation on non-diapause spider mites, (2) predator-induced diapause in spider mites, or (3) both.

  4. Silkworms transformed with chimeric silkworm/spider silk genes spin composite silk fibers with improved mechanical properties

    Science.gov (United States)

    The development of a spider silk manufacturing process is of great interest. piggyBac vectors were used to create transgenic silkworms encoding chimeric silkworm/spider silk proteins. The silk fibers produced by these animals were composite materials that included chimeric silkworm/spider silk prote...

  5. Predation by cosmopolitan spiders upon the medically significant pest species Loxosceles reclusa (Araneae: Sicariidae): limited possibilities for biological control.

    Science.gov (United States)

    Sandidge, Jamél

    2004-04-01

    Interspecific predation of three cosmopolitan house spiders, Achearanea tepidariorum (Kock 1841) (Theridiidae), Steotoda triangulosa (Walckenaer 1802) (Theridiidae), and Pholcus phalangioides (Doleschall 1859) (Pholcidae), and the medically significant brown recluse spider, Loxosceles reclusa (Sicariidae) were examined to evaluate transitive predatory relationships and to explore the potential use of cosmopolitan spiders as effective biological control agents on L. reclusa. Fifty houses from northeastern Kansas were visually inspected from May to December 2002 for cosmopolitan spiders and L. reclusa. In 25 houses, insect monitoring traps were used to sample spider diversity and abundance. The remaining 25 houses were monitored to examine intraguild predation and spider behavior. If cosmopolitan spiders have the ability to regulate or decrease L. reclusa populations, houses with large cosmopolitan spider populations are expected to have significantly fewer L. reclusa than houses without cosmopolitan spiders. Predation and/or evidence of predation by all three cosmopolitan spiders on L. reclusa was detected in 68% of houses. Spearman's rank correlation analysis showed overall positive relationships between population densities of cosmopolitan spiders and L. reclusa. When evaluated independently, the presence of both A. tepidariorum and S. triangulosa showed negative, yet nonsignificant, relationships with L. reclusa densities, whereas P. phalangioides showed a positive nonsignificant relationship. Although statistical tests showed a decrease in L. reclusa population densities with increased population densities of two cosmopolitan species, alluding to a potential beneficial interaction for biological control, observations of spider behavior, web positioning (niche partitioning), and predation showed little possibility of biological control capabilities.

  6. 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

  7. The spider Harpactea sadistica: co-evolution of traumatic insemination and complex female genital morphology in spiders

    Science.gov (United States)

    Řezáč, Milan

    2009-01-01

    The males of invertebrates from a few phyla, including arthropods, have been reported to practise traumatic insemination (TI; i.e. injecting sperm by using the copulatory organ to penetrate the female's body wall). As all previously reported arthropod examples have been insects, there is considerable interest in whether TI might have evolved independently in other arthropods. The research reported here demonstrates the first case of TI in the arthropod subphylum Chelicerata, in particular how the genital morphology and mating behaviour of Harpactea sadistica (Řezáč 2008), a spider from Israel, has become adapted specifically for reproduction based on TI. Males have needle-like intromittent organs and females have atrophied spermathecae. In other spiders, eggs are fertilized simultaneously with oviposition, but the eggs of H. sadistica are fertilized in the ovaries (internal fertilization) and develop as embryos before being laid. Sperm-storage organs of phylogenetically basal groups to H. sadistica provide males with last male sperm priority and allow removal of sperm by males that mate later, suggesting that TI might have evolved as an adaptive strategy to circumvent an unfavourable structure of the sperm-storage organs, allowing the first male to mate with paternity advantage. Understanding the functional significance of TI gives us insight into factors underlying the evolution of the genital and sperm-storage morphology in spiders. PMID:19403531

  8. Vibration transmission through sheet webs of hobo spiders (Eratigena agrestis) and tangle webs of western black widow spiders (Latrodectus hesperus).

    Science.gov (United States)

    Vibert, Samantha; Scott, Catherine; Gries, Gerhard

    2016-11-01

    Web-building spiders construct their own vibratory signaling environments. Web architecture should affect signal design, and vice versa, such that vibratory signals are transmitted with a minimum of attenuation and degradation. However, the web is the medium through which a spider senses both vibratory signals from courting males and cues produced by captured prey. Moreover, webs function not only in vibration transmission, but also in defense from predators and the elements. These multiple functions may impose conflicting selection pressures on web design. We investigated vibration transmission efficiency and accuracy through two web types with contrasting architectures: sheet webs of Eratigena agrestis (Agelenidae) and tangle webs of Latrodectus hesperus (Theridiidae). We measured vibration transmission efficiencies by playing frequency sweeps through webs with a piezoelectric vibrator and a loudspeaker, recording the resulting web vibrations at several locations on each web using a laser Doppler vibrometer. Transmission efficiencies through both web types were highly variable, with within-web variation greater than among-web variation. There was little difference in transmission efficiencies of longitudinal and transverse vibrations. The inconsistent transmission of specific frequencies through webs suggests that parameters other than frequency are most important in allowing these spiders to distinguish between vibrations of prey and courting males.

  9. Photoluminescent properties of spider silk coated with Eu-doped nanoceria

    Energy Technology Data Exchange (ETDEWEB)

    Dmitrović, Svetlana, E-mail: svetlana8@vin.bg.ac.rs [University of Belgrade, Vinča Institute of Nuclear Sciences (Serbia); Nikolić, Marko G.; Jelenković, Branislav [University of Belgrade, Institute of Physics (Serbia); Prekajski, Marija [University of Belgrade, Vinča Institute of Nuclear Sciences (Serbia); Rabasović, Mihailo [University of Belgrade, Institute of Physics (Serbia); Zarubica, Aleksandra [University of Niš, Department of Chemistry, Faculty of Science and Mathematics (Serbia); Branković, Goran [University of Belgrade, Institute for Multidisciplinary Research, Department of Material Science (Serbia); Matović, Branko [University of Belgrade, Vinča Institute of Nuclear Sciences (Serbia)

    2017-02-15

    Spider dragline silk was coated with pure as well as Eu-doped ceria nanopowders at the room temperature. The treatment was done by immersion of the spider silk mesh into aqueous solutions of cerium nitrate (Ce(NO{sub 3}){sub 3}) and ammonium hydroxide (NH{sub 4}OH). Depending on the relationship between Ce{sup 3+} ion and ammonium hydroxide concentration, coated fibers exhibited a different thickness. Obtained materials were studied by means of FESEM. It was found that ceria nanoparticles of average size of 3 nm were coated along spider thread. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) confirmed crystal nature of nanoparticle coating of spider silk. By using Williamson-Hall plots, crystallite size and strain were estimated. EDS measurement confirmed the presence of Eu in spider-Eu-doped ceria composite, and according to FTIR analysis, the interaction between CeO2 and spider silk was proposed. The morphology of obtained composite was observed by TEM. The photoluminescence emission spectra of spider silk coated with Eu-doped ceria were measured with two different excitations of 385 and 466 nm. The two-photon excited auto-fluorescence of spider silk coated with Eu-doped ceria was detected using a nonlinear laser scanning microscope. Obtained composite has a potential as a fluorescent labeling material in diverse applications.

  10. Biased interpretation and memory in children with varying levels of spider fear

    NARCIS (Netherlands)

    Klein, A.M.; Titulaer, G.; Simons, C.; Allart, E.; de Gier, E.; Bögels, S.M.; Becker, E.S.; Rinck, M.

    2014-01-01

    This study investigated multiple cognitive biases in children simultaneously, to investigate whether spider-fearful children display an interpretation bias, a recall bias, and source monitoring errors, and whether these biases are specific for spider-related materials. Furthermore, the independent

  11. 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.

  12. Linking native and invader traits explains native spider population responses to plant invasion

    Science.gov (United States)

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

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Barr, Jonathan L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tuffner, Francis K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hadley, Mark D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schneider, Kevin P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    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. Colourful orb-weaving spiders, Nephila pilipes, through a bee's eyes.

    Science.gov (United States)

    Tso, I-Min; Lin, Chih-Wei; Yang, En-Cheng

    2004-07-01

    Many orb-weaving spiders in the tropics forage in open sites during the day and some of them have both bright and dark colourations. The conspicuous UV-reflective colour markings of these spiders have been reported to be attractive to visually oriented prey and thus could increase the spiders' foraging success. Using a combination of field and laboratory studies, we examine whether or not the body colouration of orb-weaving spiders exhibits optical properties that are attractive to insect prey from the viewpoint of insect visual physiology. We compared the prey interception rates and colour contrasts of the typical and melanic morphs of the giant wood spider, Nephila pilipes. Results of the field study showed that the typical morph caught significantly more insects than the melanic morph. Colour contrasts calculated from spectral reflectances of the background and body surface of spiders showed that the brightly coloured body parts of the typical morph exhibited rather high values, but those of the dark body parts were below the discrimination threshold. The differential colour contrasts of body parts generated a visual signal unlike that of a spider but rather like certain forms of food resources. On the other hand, the melanic morphs did not have bright colouration and the colour contrasts of every part of the body were significantly higher than the threshold, making the contour of spiders quite clear to bees.

  15. In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction

    NARCIS (Netherlands)

    Steins, A.; Dik, P.; Müller, W.H.; Vervoort, S.J.; Reimers, K.; Kubhier, J.W.; Vogt, P.M.; van Apeldoorn, Aart A.; Coffer, P.J.; Schepers, K.

    2015-01-01

    Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial

  16. 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

  17. The spider anxiety and disgust screening for children: Reliability and validity of a screening for children

    NARCIS (Netherlands)

    Klein, A.M.; Niekerk, R.E. van; Baartmans, J.M.D.; Rinck, M.; Becker, E.S.

    2017-01-01

    Objectives: Specific fears, such as fear of spiders, are often used as a model for studying the development of other fears because several studies suggest that the underlying processes of fear are similar. For the screening of spider fear in children, a good, fast, and reliable screening instrument

  18. Contamination vs. harm-relevant outcome expectancies and covariation bias in spider phobia

    NARCIS (Netherlands)

    de Jong, Peter J.; Peters, Madelon L.

    There is increasing evidence that spiders are not feared because of harmful outcome expectancies but because of disgust and contamination-relevant outcome expectancies. This study investigated the relative strength of contamination- and harm-relevant UCS expectancies and covariation bias in spider

  19. 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...

  20. 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. © 2013 Published by Elsevier Ireland Ltd.

  1. Brown recluse spider (Loxosceles reclusa) envenomation leading to acute hemolytic anemia in six adolescents

    OpenAIRE

    McDade, Jenny; Aygun, Banu; Ware, Russell E.

    2010-01-01

    Loxosceles reclusa (brown recluse spider) bites often cause local envenomation reactions, however acute hemolysis from systemic loxoscelism is rare. To highlight this important diagnostic consideration for unexplained hemolysis in areas endemic for brown recluse spiders, we report six adolescents with acute hemolytic anemia from presumed L. reclusa bites.

  2. Brown recluse spider (Loxosceles reclusa) envenomation leading to acute hemolytic anemia in six adolescents.

    Science.gov (United States)

    McDade, Jenny; Aygun, Banu; Ware, Russell E

    2010-01-01

    Loxosceles reclusa (brown recluse spider) bites often cause local envenomation reactions; however, acute hemolysis from systemic loxoscelism is rare. To highlight this important diagnostic consideration for unexplained hemolysis in areas endemic for brown recluse spiders, we report on 6 adolescents with acute hemolytic anemia from presumed L reclusa bites.

  3. 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

  4. Parasitization of a huntsman spider (Arachnida: Araneae: Sparassidae: Heteropoda venatoria by a mermithid nematode (Nematoda: Mermithidae

    Directory of Open Access Journals (Sweden)

    Sachin P. Ranade

    2016-11-01

    Full Text Available The emergence of a mermithid worm from a huntsman spider Heteropoda venatoria was witnessed at Buxa Tiger Reserve, West Bengal.  It appears to be a first record of the spider family Sparassidae serving as a host for a member of the family Mermithidae. 

  5. Development and initial validation of an abbreviated Spider Phobia Questionnaire using item response theory

    NARCIS (Netherlands)

    Olatunji, Bunmi O.; Woods, Carol M.; de Jong, Peter J.; Teachman, Bethany A.; Sawchuk, Craig N.; David, Bieke

    An abbreviated Spider Phobia Questionnaire (SPQ) was developed using methods based in item response theory. Fifteen of the 31 SPQ items that demonstrated good to excellent discrimination along the spider fear continuum were retained in Study 1 that consisted of 1,555 nonclinical and clinical

  6. Of spiders and zebras: publication of inadequately documented loxoscelism case reports.

    Science.gov (United States)

    Vetter, Richard S; Swanson, David L

    2007-06-01

    The dermatology and general medical literature is filled with articles that report skin disease caused by the brown recluse spider, Loxosceles reclusa. A large number of these articles contain inadequate documentation of Loxosceles bites; many come from areas that have no Loxosceles spiders. Authors submitting papers alleging loxoscelism should adhere to standards of evidence when writing case reports.

  7. Prosoma shape and araneophagy in Linyphiidae and other spider families (Arachnida; Araneae)

    NARCIS (Netherlands)

    Heuts, B.; Brunt, T.

    2009-01-01

    Adult males of linyphiid spider genera with a domed masculine prosoma shape and/or with a protuberance on the prosoma, showed a marginally significant higher killing potential (predation on spiders of various families surpassing the individuals of the killing genera in three body size measures) than

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

    Science.gov (United States)

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

  9. 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…

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

    NARCIS (Netherlands)

    Villarroel, C.A.; Jonckheere, W.; Alba Cano, J.M.; Glas, J.J.; Dermauw, W.; Haring, M.A.; Van Leeuwen, T.; Schuurink, R.C.; Kant, M.R.

    2016-01-01

    Spider mites (Tetranychidae sp.) are widely occurring arthropod pests on cultivated plants. Feeding by the two-spotted spider mite T. urticae, a generalist herbivore, induces a defense response in plants that mainly depends on the phytohormones jasmonic acid and salicylic acid (SA). On tomato

  11. 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

  12. 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.

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

    Science.gov (United States)

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

    2011-11-01

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

  14. Incompatibility associated with the bite of a brown recluse spider (Loxosceles reclusa).

    Science.gov (United States)

    Hardman, J T; Beck, M L; Hardman, P K; Stout, L C

    1983-01-01

    Red cell samples from a patient who was suffering from massive hemolysis due to a brown recluse spider (Loxosceles reclusa) bite were found to be reactive by indirect antiglobulin test with most ABO-compatible serum samples. Spider venom, enzymes related to those in spider venom, and antisera to plasma proteins and Rh antigens were used to investigate the unusual reactivity of the patient's cells. IgG was detected on the patient's cells by indirect antiglobulin tests. Cells treated with brown recluse spider venom or phosphatidylcholine phosphatidohydrolase reacted similarly. These findings suggest that sphingomyelinase D, which has been identified in brown recluse spider venom, may be related to the unusual reactivity of the patient's cells. Unexpected reactions were observed when venom-treated cells were tested with Rh antibodies: O negative cells absorbed and eluted anti-D from Rh immune globulin; E negative cells were reactive with a commercial anti-E reagent.

  15. 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

  16. Resistance status of the carmine spider mite, Tetranychus cinnabarinus and the twospotted spider mite, Tetranychus urticae to selected acaricides on strawberries.

    Science.gov (United States)

    Bi, Jian-Long; Niu, Zi-Mian; Yu, Lu; Toscano, Nick C

    2016-02-01

    The carmine spider mite, Tetranychus cinnabarinus (Boisduval) and the twospotted spider mite, Tetranychus urticae Koch, are serious pests of strawberries and many other horticultural crops. Control of these pests has been heavily dependent upon chemical acaricides. Objectives of this study were to determine the resistance status of these two pest species to commonly used acaricides on strawberries in a year-round intensive horticultural production region. LC90 of abamectin for adult carmine spider mites was 4% whereas that for adult twospotted spider mites was 24% of the top label rate. LC90s of spiromesifen, etoxazole, hexythiazox and bifenazate were 0.5%, 0.5%, 1.4% and 83% of their respective highest label rates for carmine spider mite eggs, 0.7%, 2.7%, 12.1% and 347% of their respective highest label rates for the nymphs. LC90s of spiromesifen, etoxazole, hexythiazox and bifenazate were 4.6%, 11.1%, 310% and 62% of their respective highest label rates for twospotted spider mite eggs, 3%, 13%, 432,214% and 15% of their respective highest label rates for the nymphs. Our results suggest that T. cinnabarinus have developed resistance to bifenazate and that the T. urticae have developed resistance to hexythiazox. These results strongly emphasize the need to develop resistance management strategies in the region. © 2014 Institute of Zoology, Chinese Academy of Sciences.

  17. The distribution of brown recluse spiders in the southeastern quadrant of the United States in relation to loxoscelism diagnoses.

    Science.gov (United States)

    Vetter, Richard S

    2009-05-01

    The southern and eastern margins of the range of the brown recluse spider run through the southeastern quadrant of the United States. Populations vary from abundant in states such as Arkansas and west and central Kentucky and Tennessee to absent in the Atlantic seaboard states. The diagnosis of loxoscelism should be restricted to areas of the southeastern United States where brown recluse spiders are both common and widespread. Better knowledge of the local presence of recluse spiders in one's area, along with the list of differential diagnoses for dermonecrosis, will allow medical personnel in the south to better assess the probability of spider involvement in a necrotic skin lesion. In North America, there are two groups of spiders proven to be medically important: the widow spiders (genus Latrodectus) and the recluse spiders (genus Loxosceles). The widow spiders are a known entity, because their distinctive coloration makes them readily identifiable by nonarachnologists. Also, the physiological mechanism of the venom, the antivenom to counter it, and the symptoms are known, causing misdiagnosis to rarely occur. In contrast, recluse spiders are almost at the other end of the spectrum. They are readily misidentified or confused with harmless spiders, and the physiological mechanism of the venom is still being elucidated. Furthermore, no antivenom is commercially available, and the brown recluse's infamy causes many skin lesions of nonarachnid origin to be misdiagnosed as brown recluse spider bites.

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

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    A. V. Ponomarev

    2014-01-01

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

  19. Native spider silk as a biological optical fiber

    Science.gov (United States)

    Huby, N.; Vié, V.; Renault, A.; Beaufils, S.; Lefèvre, T.; Paquet-Mercier, F.; Pézolet, M.; Bêche, B.

    2013-03-01

    In this study, we demonstrate the use of eco-friendly native spider silk as an efficient optical fiber in air, highly bent fibers, and physiological liquid. We also integrated the silk filament in a photonic chip made of polymer microstructures fabricated by UV lithography. The molding process is non-destructive for silk and leads to an efficient micro-optical coupling between silk and synthetic optical structures. These optical performances combined with the unique biocompatibility, bioresorbability, flexibility, and tensile strength of silk filaments pave the way for new applications in biological media and for original biophotonic purposes.

  20. Back in Europe: Quamtana spiders (Araneae: Pholcidae in Germany

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    Huber, Bernhard

    2015-11-01

    Full Text Available Two undescribed species of the African pholcid spider genus Quamtana have been found in German greenhouses and plant markets since 2012. Both species seem to have established stable populations. This genus has not been previously recorded from Europe, except for a fossil specimen in Eocene amber from the Paris Basin that was tentatively assigned to Quamtana and that is estimated to date from 53 million years ago. Since the actual geographic origins of the two species (probably South and/or tropical Africa are unknown, we do not formally describe them.

  1. Structure determination of spider silk from X-ray images

    Energy Technology Data Exchange (ETDEWEB)

    Ulrich, Stephan; Zippelius, Annette [Universitaet Goettingen, Institut fuer Theoretische Physik (Germany); Meling, Martin [Max-Planck-Institut fuer biophysikalische Chemie, Goettingen (Germany); Glisovic, Anja; Salditt, Tim [Universitaet Goettingen, Institut fuer Roentgenphysik (Germany)

    2008-07-01

    Spider silk consists of interconnected crystallites, which are typically aligned along the fiber axis. We present a method to systematically determine the structure of these crystallites. Hereby we introduce a model that calculates the scattering function G(q) which is fitted to the measured X-ray image (silk from nephila clavipes). With it, the crystallites' size, the constitution and dimensions of their unit cell, as well as their tilt with respect to the fiber axis is identified, and furthermore the effect of coherent scattering from different crystallites is investigated. The shown methods and the presented model can easily be generalized to a wide class of composite materials.

  2. Brown recluse spider bite to the upper lip.

    Science.gov (United States)

    Dare, Ryan K; Conner, Kelly B; Tan, Poliana C; Hopkins, Robert H

    2012-03-01

    Brown recluse spiders are predominantly found in south central United States. Their bites usually cause mild self-limiting reactions, although localized tissue necrosis and rare systemic, potentially fatal, envenomations are known to occur. Herein, we report an atypical presentation of a brown recluse bite in a 20 year old female who was admitted to the intensive care unit due to angioedema and cellulitis. We photographically document the bite site for twenty-four hours following envenomation. She received glucocorticoids, antihistamines, antibiotics and dapsone while hospitalized and was subsequently discharged with complete resolution of symptoms without the development of tissue necrosis or scarring.

  3. A revision of the spider genus Zaitunia (Araneae, Filistatidae)

    OpenAIRE

    Sergei Zonstein; Marusik, Yuri M.

    2016-01-01

    The spider genus Zaitunia Lehtinen, 1967 (Araneae, Filistatidae) is revised. It was found to include 24 species distributed in the Eastern Mediterranean, Middle East and Central Asia: ♀ Z. afghana (Roewer, 1962) (Afghanistan), ♀ Z. alexandri Brignoli, 1982 (Iran), ♀ Z. akhanii Marusik & Zamani, 2015 (Iran), ♂♀ Z. annulipes (Kulczyński, 1908) (Cyprus), ♂♀ Z. beshkentica (Andreeva & Tyshchenko, 1969) (Tajikistan, Uzbekistan), ♀ Z. brignoliana sp. nov. (Iran), ♂♀ Z. ferghanensis sp. nov...

  4. We prefer what we fear: A response preference bias mimics attentional capture in spider fear.

    Science.gov (United States)

    Haberkamp, Anke; Biafora, Melanie; Schmidt, Thomas; Weiß, Katharina

    2018-01-01

    The extent to which emotionally significant stimuli capture visual attention remains elusive because a preference for reporting or choosing emotionally significant stimuli could mimic attentional capture by these stimuli. We conducted two prior-entry experiments to disentangle whether phobic and fear-relevant stimuli capture attention or merely produce a response bias in spider-fearful participants. Prior entry denotes the effect that attended stimuli are perceived earlier than unattended stimuli as indicated by temporal order judgments. We presented phobic (spiders), fear-relevant (snakes) and neutral stimuli in pairs with varying temporal onset. The participants' task was to indicate which stimulus was presented first (Experiment 1) or second (Experiment 2). In the first experiment, spider-fearful but not control participants indicated that they had perceived spiders as occurring earlier in time, suggesting a prior-entry effect for spiders in this group. But surprisingly, in the second experiment, spider-fearful participants indicated more frequently that they had seen spiders as being presented second. This finding rules out a genuine prior-entry effect and instead suggests a strong preference for the response option associated with the feared animal. This response bias may result from a hypervigilance toward the feared stimulus and contribute to maintaining avoidance behavior in individuals with specific phobias. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    de Jong, P J; Vorage, I; van den Hout, M A

    2000-11-01

    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 condition (EXP) or to the exposure with counterconditioning condition (CC). In the CC-condition tasty food-items were used during the regular exposure exercises and the participants' favourite music was played. Both treatment conditions appeared very effective in reducing avoidance behaviour and self-reported fear of spiders, strongly attenuated the disgusting properties of spiders and altered the affective evaluations in a positive direction. CC was not more effective in altering the affective valence of spiders than EXP and was not superior with respect to the long term treatment efficacy at 1 year follow up. Apparently, regular exposure treatment is already quite effective in altering the affective-evaluative component of spider phobia and it remains to be seen whether it is possible to further improve treatment outcome by means of procedures which are specifically designed to reduce the spiders' negative affective valence.

  6. 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.

  7. 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.

  8. 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.

  9. Environmental and hormonal factors controlling reversible colour change in crab spiders.

    Science.gov (United States)

    Llandres, Ana L; Figon, Florent; Christidès, Jean-Philippe; Mandon, Nicole; Casas, Jérôme

    2013-10-15

    Habitat heterogeneity that occurs within an individual's lifetime may favour the evolution of reversible plasticity. Colour reversibility has many different functions in animals, such as thermoregulation, crypsis through background matching and social interactions. However, the mechanisms underlying reversible colour changes are yet to be thoroughly investigated. This study aims to determine the environmental and hormonal factors underlying morphological colour changes in Thomisus onustus crab spiders and the biochemical metabolites produced during these changes. We quantified the dynamics of colour changes over time: spiders were kept in yellow and white containers under natural light conditions and their colour was measured over 15 days using a spectrophotometer. We also characterised the chemical metabolites of spiders changing to a yellow colour using HPLC. Hormonal control of colour change was investigated by injecting 20-hydroxyecdysone (20E) into spiders. We found that background colouration was a major environmental factor responsible for colour change in crab spiders: individuals presented with white and yellow backgrounds changed to white and yellow colours, respectively. An ommochrome precursor, 3-OH-kynurenine, was the main pigment responsible for yellow colour. Spiders injected with 20E displayed a similar rate of change towards yellow colouration as spiders kept in yellow containers and exposed to natural sunlight. This study demonstrates novel hormonal manipulations that are capable of inducing reversible colour change.

  10. Brain dynamics in spider-phobic individuals exposed to phobia-relevant and other emotional stimuli.

    Science.gov (United States)

    Michalowski, Jaroslaw M; Melzig, Christiane A; Weike, Almut I; Stockburger, Jessica; Schupp, Harald T; Hamm, Alfons O

    2009-06-01

    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 positive potential (LPP) during the encoding of phobia-relevant pictures compared to nonfearful controls. No group differences were observed for standard emotional materials indicating that these effects were specific to phobia-relevant material. Within group comparisons of the spider phobia group, though, revealed comparable EPN and LPP evoked by spider pictures and emotional (unpleasant and pleasant) picture contents. These results demonstrate a temporal unfolding in perceptual processing from unspecific vigilance (P1) to preferential responding (EPN and LPP) to phobia-relevant materials in the spider phobia group. However, at the level of early stimulus processing, these effects of increased attention seem to be related to emotional relevance of the stimulus cues rather than reflecting a fear-specific response.

  11. Heat Tolerance of the Brown Recluse Spider (Araneae: Sicariidae): Potential for Pest Control.

    Science.gov (United States)

    Cramer, Kenneth L; Zagar, Lindsey M

    2016-02-01

    The brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, is a well-known venomous spider common in the south-central United States where infestations can reach thousands of individuals in a single structure. Bites from this spider pose a risk of dermonecrotic lesions (loxoscelism) or, rarely, more serious systemic effects. The heat tolerance of this spider is understudied but may offer an alternative pest control solution to pesticides or fumigation, both of which have their disadvantages. We subjected brown recluse spiders to increasing temperatures to establish the upper lethal temperature (LT). Using probit analysis to generate probability of mortality at increasing temperatures, we then exposed adult spiders to the observed LT50 to simulate whole-room heat treatment. Laboratory results predict exposure to 48°C for 130 min will achieve 100% mortality of adult spiders. Field tests need to be conducted to determine the efficacy of heat treatment in a variety of real-world situations. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Osteomyelitis of the mandibular symphysis caused by brown recluse spider bite.

    Science.gov (United States)

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

    2008-08-28

    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. 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 spider bites are presented. Osteomyelitis of the mandible causing a chronic wound was the presenting finding of a patient with a history of spider bite and exposure to brown recluse spiders. Operative debridement and wound closure resulted in successful treatment. Brown recluse spider envenomation varies in its presentation and treatment is based on the presenting clinical picture. Treatment regimens for brown recluse spider bite envenomation should include the basics of wound care. Systemic antibiotics, topical antimicrobials, dapsone, and surgical debridement are valuable adjuncts of treatment, as indicated, based on the clinical course.

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

    Science.gov (United States)

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

    2015-02-01

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

  14. Ant-mediated indirect negative effects of aphids on spider mites living on the same plant.

    Science.gov (United States)

    Adachi, Masaaki; Yano, Shuichi

    2017-05-01

    Some aphid species are known to have mutualistic relationships with tending ants; that is, the aphids supply the ants with honeydew and are protected by the ants. Although spider mites and honeydew-producing aphids often live on the same host plant, it has not previously been determined whether the ants tending these aphids affect spider mite survival. Using replicated microcosms, each containing an artificial ant nest, we compared experimentally the survival of two-spotted spider mites on kidney bean plants with and without cowpea aphids. Our results showed significantly fewer spider mites on plants with aphids, indicating that spider mites were preyed upon by ants tending aphids. On the other hand, there was no detectable plant-mediated indirect effect of aphids on mite performance in the microcosms. Therefore, we conclude that aphids indirectly reduced the survival of spider mites living on the same host plant via their tending ants. Nonetheless, spider mites did not avoid settling on plant leaves infested with aphids.

  15. Spider mites adaptively learn recognizing mycorrhiza-induced changes in host plant volatiles.

    Science.gov (United States)

    Patiño-Ruiz, J David; Schausberger, Peter

    2014-12-01

    Symbiotic root micro-organisms such as arbuscular mycorrhizal fungi commonly change morphological, physiological and biochemical traits of their host plants and may thus influence the interaction of aboveground plant parts with herbivores and their natural enemies. While quite a few studies tested the effects of mycorrhiza on life history traits, such as growth, development and reproduction, of aboveground herbivores, information on possible effects of mycorrhiza on host plant choice of herbivores via constitutive and/or induced plant volatiles is lacking. Here we assessed whether symbiosis of the mycorrhizal fungus Glomus mosseae with common bean plants Phaseolus vulgaris influences the response of the two-spotted spider mite Tetranychus urticae to volatiles of plants that were clean or infested with spider mites. Mycorrhiza-naïve and -experienced spider mites, reared on mycorrhizal or non-mycorrhizal bean plants for several days before the experiments, were subjected to Y-tube olfactometer choice tests. Experienced but not naïve spider mites distinguished between constitutive volatiles of clean non-mycorrhizal and mycorrhizal plants, preferring the latter. Neither naïve nor experienced spider mites distinguished between spider mite-induced volatiles of mycorrhizal and non-mycorrhizal plants. Learning the odor of clean mycorrhizal plants, resulting in a subsequent preference for these odors, is adaptive because mycorrhizal plants are more favorable host plants for fitness of the spider mites than are non-mycorrhizal plants.

  16. Phantom spiders 2: More notes on dubious spider species from Europe

    Directory of Open Access Journals (Sweden)

    Breitling, Rainer

    2016-09-01

    Full Text Available A surprisingly large number of European spider species have never been reliably rediscovered since their first description many decades ago. Most of these are probably synonymous with other species or unidentifiable, due to insufficient descriptions or missing type material. In this second part of a series on this topic, we discuss about 100 of these cases, focusing mainly on species described in the early 20th century by Pelegrín Franganillo Balboa and Gabor von Kolosváry, as well as a number of jumping spiders and various miscellaneous species. In most cases, the species turned out to be unidentifiable nomina dubia, but for some of them new synonymies could be established as follows: Alopecosa accentuata auct., nec (Latreille, 1817 = Alopecosa farinosa (Herman, 1879 syn. nov., comb. nov.; Alopecosa barbipes oreophila Simon, 1937 = Alopecosa farinosa (Herman, 1879 syn. nov., comb. nov.; Alopecosa mariae orientalis (Kolosváry, 1934 = Alopecosa mariae (Dahl, 1908 syn. nov.; Araneus angulatus afolius (Franganillo, 1909 and Araneus angulatus atricolor Simon, 1929 = Araneus angulatus Clerck, 1757 syn. nov.; Araneus angulatus castaneus (Franganillo, 1909 = Araneus pallidus (Olivier, 1789 syn. nov.; Araneus angulatus levifolius (Franganillo, 1909, Araneus angulatus niger (Franganillo, 1918 and Araneus angulatus nitidifolius (Franganillo, 1909 = Araneus angulatus Clerck 1757 syn. nov.; Araneus angulatus pallidus (Franganillo, 1909, Araneus angulatus crucinceptus (Franganillo, 1909, Araneus angulatus fuscus (Franganillo, 1909 and Araneus angulatus iberoi (Franganillo, 1909 = Araneus pallidus (Olivier, 1789 syn. nov.; Araneus circe strandi (Kolosváry, 1935 = Araneus circe (Audouin, 1826 syn. nov.; Araneus diadematus nemorosus Simon, 1929 and Araneus diadematus soror (Simon, 1874 = Araneus diadematus Clerck, 1757 syn. nov.; Araneus pyrenaeus (Simon, 1874 = Araneus pallidus (Olivier, 1789 syn. nov.; Araneus sericinus (Roewer, 1942 = Aculepeira armida

  17. 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.

  18. Nonhealing Wounds Caused by Brown Spider Bites: Application of Hyperbaric Oxygen Therapy.

    Science.gov (United States)

    Hadanny, Amir; Fishlev, Gregory; Bechor, Yair; Meir, Oshra; Efrati, Shai

    2016-12-01

    Bites by Loxosceles spiders (also known as recluse spiders or brown spiders) can cause necrotic ulcerations of various sizes and dimensions. The current standard of care for brown spider bites includes analgesics, ice, compression, elevation, antihistamines, and surgical debridement. Hyperbaric oxygen therapy (HBOT) in the treatment of brown spider bites has been administered in the early stage of ulceration, or 2 to 6 days after the bite. Unfortunately, the diagnosis of spider bite-related ulcers is often delayed and weeks or months may elapse before HBOT is considered. To evaluate the effect of HBOT on nonhealing wounds caused by brown spider bites in the late, chronic, nonhealing stage. Analysis of 3 patients with brown spider-bite healing wounds treated at The Sagol Center for Hyperbaric Medicine and Research in Israel. Patients presented 2 to 3 months after failure of other therapies including topical dressings, antibiotics, and corticosteroids. All patients were treated with daily 2 ATA (atmospheres absolute) with 100% oxygen HBOT sessions. All 3 patients were previously healthy without any chronic disease. Their ages were 30, 42, and 73 years. They were treated once daily for 13, 17, and 31 sessions, respectively. The wounds of all 3 patients healed, and there was no need for additional surgical intervention. There were no significant adverse events in any of the patients. Microvascular injury related to brown spider bites may culminate in ischemic nonhealing wounds even in a relatively young, healthy population. Hyperbaric oxygen therapy should be considered as a valuable therapeutic tool even months after the bite.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Roberson

    2016-09-01

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

  1. 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...... consecutive 12-h periods, alternating between white and red (lambda > 600 nm) illumination. Male spiders were significantly more locomotor active than female spiders under both lighting conditions. They walked, on average, twice the distance of females, employed higher velocities, and spent less time...

  2. 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

    Spider (Araneae) assemblages were studied over two years by pitfall trapping along an urbanisation gradient of forested habitats (rural forest - suburban forest fragment - urban forest fragment) in a Danish town, using the Globenet protocol. During the two years, we collected 4340 individuals of 90...... 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...

  3. X-ray Diffraction and Neutron Scattering Analysis of Natural and Synthetic Spider Silk Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Randolph [Utah State Univ., Logan, UT (United States)

    2013-11-11

    Spider silks have the potential to provide new bio-inspired materials for numerous applications in bioenergetics and products ranging from protective clothing to artificial ligaments and tendons. A number of spider silk genes have been cloned and sequenced by the Lewis laboratory revealing the basis for understanding the key elements of spider silk proteins with respect to their materials performance. In particular, specific amino acid motifs have been identified which have been conserved for over 125 million years in all spiders that use their silk to physically trap prey. The key element in taking the next step toward generating bio-based materials from spider silks will be to move from the current descriptive data to predictive knowledge. Current efforts are focused on mimicking spider silk through synthetic proteins. In developing synthetic silk fibers, we first need to understand the complete secondary and tertiary structure of natural silk so that we can compare synthetic constructs to the natural material. Being able to compare the structure on a single fiber level is critical to the future of molecular directed mimic development because we can vary mechanical properties by different spinning methods. The new generation of synchrotron x-ray diffraction and neutron beamlines will allow, for the first time, determination of the molecular structure of silk fibers and synthetic mimics. We propose an exciting new collaborative research team working jointly between Argonne National Laboratory, Arizona State U. and the University of Wyoming to address the ?characterization of synthetic and natural spider silk fibers using x-ray and neutron diffraction.? Thus these new methodologies will provide understanding of current fibers and determine changes needed to produce fibers with specific properties. The following specific aims are proposed: ? Synthesize spider silk fibers with molecular structures mimicking that of natural silks. Test the mechanic properties of these

  4. Catching of spiders in shallow subterranean habitats in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Růžička, Vlastimil

    2016-04-01

    Full Text Available Spiders occurring in soils and fissured rocks were investigated using pipe traps. Four microphthalmic species, namely Hahnia microphthalma, Porrhomma egeria, P. microps and P. cambridgei were collected. Hahnia microphthalma is reported from the Czech Republic for the first time. The importance of collecting material by complex pipe traps (consisting of a perforated pipe and a set of removable cups to record the depth distribution of spiders in subterranean habitats is stressed. The importance of the soil and fissure network formed by sandy marlite bedrock and of alluvial soils for the life of subterranean spiders is documented.

  5. Towards a new generation of fibre optic chemical sensors based on spider silk threads

    Science.gov (United States)

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

    2017-04-01

    A spider uses up to seven different types of silk, all having specific functions, to build its web. For scientists, native silk - directly extracted from spiders - is a tough, biodegradable and biocompatible thread used mainly for tissue engineering and textile applications. Blessed with outstanding optical properties, this protein strand can also be used as an optical fibre and is, moreover, intrinsically sensitive to chemical compounds. In this communication, a pioneering proof-of-concept experiment using spider silk, in its pristine condition, as a new type of fibre-optic relative humidity sensor will be demonstrated and its potential for future applications discussed.

  6. A dragline-forming mobile robot inspired by spiders.

    Science.gov (United States)

    Wang, Liyu; Culha, Utku; Iida, Fumiya

    2014-03-01

    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.

  7. An insecticidal toxin from Nephila clavata spider venom.

    Science.gov (United States)

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

    2017-07-01

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

  8. Relationships between supercontraction and mechanical properties of spider silk

    Science.gov (United States)

    Liu, Yi; Shao, Zhengzhong; Vollrath, Fritz

    2005-12-01

    Typical spider dragline silk tends to outperform other natural fibres and most man-made filaments. However, even small changes in spinning conditions can have large effects on the mechanical properties of a silk fibre as well as on its water uptake. Absorbed water leads to significant shrinkage in an unrestrained dragline fibre and reversibly converts the material into a rubber. This process is known as supercontraction and may be a functional adaptation for the silk's role in the spider's web. Supercontraction is thought to be controlled by specific motifs in the silk proteins and to be induced by the entropy-driven recoiling of molecular chains. In analogy, in man-made fibres thermal shrinkage induces changes in mechanical properties attributable to the entropy-driven disorientation of `unfrozen' molecular chains (as in polyethylene terephthalate) or the `broken' intermolecular hydrogen bonds (as in nylons). Here we show for Nephila major-ampullate silk how in a biological fibre the spinning conditions affect the interplay between shrinkage and mechanical characteristics. This interaction reveals design principles linking the exceptional properties of silk to its molecular orientation.

  9. 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

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

    Science.gov (United States)

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

    2015-11-01

    Whip spiders (Amblypygi) are a small, cryptic order of arachnids mainly distributed in the tropics. Some basal lineages (families Charinidae and Charontidae) have adhesive pads on the tips of their six walking legs. The present study describes the macro- and ultrastructure of these pads and investigates their contact mechanics and adhesive strength on smooth and rough substrates. Furthermore, the structure of the pretarsus and its kinematics are compared in Charon cf. grayi (with an adhesive pad) and Phrynus longipes (without an adhesive pad). The adhesive pads exhibit an elaborate structure with a unique combination of structural features of smooth and hairy foot pads including a long transversal contact zone performing lateral detachment, a thick internally-branched cuticle with longitudinal ribs and hexagonal surface microstructures with spatulate keels. The contact area of the pads on smooth glass is discontinuous due to the spatulate microstructures with a discontinuous detachment, which could be observed in vivo by high speed videography at a rate of up to 10,000 fps. Adhesive strength was measured with vertical whole animal pull-off tests, obtaining mean values between 55 and 200 kPa. The occurrence of viscous lipid secretions between microstructures was occasionally observed, which, however, seems not to be a necessity for good foothold. The results are discussed in relation to the whip spider's ecology and evolution. Structure-function relationships of the adhesive pads are compared to those of insects and vertebrates. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Endogenous cortisol levels influence exposure therapy in spider phobia.

    Science.gov (United States)

    Lass-Hennemann, Johanna; Michael, Tanja

    2014-09-01

    Previous research in patients with phobia showed that the administration of glucocorticoids reduces fear in phobic situations and enhances exposure therapy. Glucocorticoids underlie a daily cycle with a peak in the morning and low levels during the evening and night. The aim of the present study was to investigate whether exposure is more effective when conducted in the morning when endogenous cortisol levels are high. Sixty patients meeting DSM IV criteria for specific phobia (animal type) were randomly assigned to one-session exposure treatment either at 08.00 a.m. (high cortisol group) or at 06.00 p.m. (low cortisol group). Participants returned for a posttreatment assessment one week after therapy and a follow-up assessment three months after therapy. Both groups showed good outcome, but patients treated in the morning exhibited significantly less fear of spiders in the behavioral approach test (BAT) and a trend for lower scores on the Fear of Spiders Questionnaire (FSQ) than patients treated in the evening. This effect was present at posttreatment and follow-up. Our findings indicate that exposure therapy is more effective in the morning than in the evening. We suggest that this may be due to higher endogenous cortisol levels in the morning group that enhance extinction memory. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Hubbard, Jonathan J; James, Laura P

    2011-03-01

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

  13. Wound assessment of the Loxosceles reclusa spider bite.

    Science.gov (United States)

    Clowers, T D

    1996-08-01

    The purpose of this study was to determine the data that are most important for nurses to recognize in the assessment of a Loxosceles reclusa (brown recluse) spider bite. Given such assessment elements, it may be possible to decrease the severity of complications and complexity of care by providing the most appropriate therapy. This study involved a retrospective review of 39 identified patient charts. Aspects that were examined included demographics, wound assessments, and outcome data. Patients who came to the study facility within 48 hours of the bite and whose diagnosis was a probable or possible brown spider bite met inclusion criteria. Data analysis revealed that the majority of patients sustained bites on the extremities and that those bites produced the most commonly noted symptoms. This is the first study in which specific local and systemic symptoms have been quantified and related to the wound area. Because of varied treatment and limited follow-up, determining the relationship between wound assessment and outcome was problematic. Ongoing studies, in contrast to retrospective review, are needed to reduce the limitations of this study, such as the loss of patients to follow-up. Areas for further research include the replication of this study and detailed analysis of treatment variables in relation to wound outcome.

  14. Tetracycline Reduces Kidney Damage Induced by Loxosceles Spider Venom

    Directory of Open Access Journals (Sweden)

    Cinthya Kimori Okamoto

    2017-03-01

    Full Text Available Envenomation by Loxosceles spider can result in two clinical manifestations: cutaneous and systemic loxoscelism, the latter of which includes renal failure. Although incidence of renal failure is low, it is the main cause of death, occurring mainly in children. The sphingomyelinase D (SMase D is the main component in Loxosceles spider venom responsible for local and systemic manifestations. This study aimed to investigate the toxicity of L. intermedia venom and SMase D on kidney cells, using both In vitro and in vivo models, and the possible involvement of endogenous metalloproteinases (MMP. Results demonstrated that venom and SMase D are able to cause death of human kidney cells by apoptosis, concomitant with activation and secretion of extracellular matrix metalloproteases, MMP-2 and MMP-9. Furthermore, cell death and MMP synthesis and secretion can be prevented by tetracycline. In a mouse model of systemic loxoscelism, Loxosceles venom-induced kidney failure was observed, which was abrogated by administration of tetracycline. These results indicate that MMPs may play an important role in Loxosceles venom-induced kidney injury and that tetracycline administration may be useful in the treatment of human systemic loxoscelism.

  15. 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.

  16. 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.

  17. Recombinant spider silk matrices for neural stem cell cultures.

    Science.gov (United States)

    Lewicka, Michalina; Hermanson, Ola; Rising, Anna U

    2012-11-01

    Neural stem cells (NSCs) have the capacity to differentiate into neurons, astrocytes, and oligodendrocytes. Accordingly, NSCs hold great promise in drug screening and treatment of several common diseases. However, a major obstacle in applied stem cell research is the limitation of synthetic matrices for culturing stem cells. The objective of this study was to evaluate the suitability of recombinant spider silk (4RepCT) matrices for growth of NSCs. NSCs isolated from the cerebral cortices of mid-gestation rat embryos were cultured on either 4RepCT matrices or conventional poly-L-ornithine and fibronectin (P + F) coated polystyrene plates. From 48 h of culture, no significant differences in cell proliferation or viability were detected in NSC cultures on 4RepCT compared to control matrices (polystyrene plates coated with P + F). The NSCs retained an undifferentiated state, displaying low or no staining for markers of differentiated cells. Upon stimulation NSCs grown on 4RepCT differentiated efficiently into neuronal and astrocytic cells to virtually the same degree as control cultures, but a slightly less efficient oligodendrocyte differentiation was noted. We suggest that recombinant spider silk matrices provide a functional microenvironment and represent a useful tool for the development of new strategies in neural stem cell research. Copyright © 2012. Published by Elsevier Ltd.

  18. Accumulation of Major and Trace Elements in Spider Webs.

    Science.gov (United States)

    Rybak, Justyna

    The spider webs of Malthonica ferruginea (Panzer, 1804) from the Agelenidae family were used for the evaluation of heavy metal contamination, and major and trace elements presence in the air of Wrocław, Poland. The concentrations of 16 elements were determined (Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, W, Pt, and Pb). Samples of webs were collected from six different locations with low, moderate, and high pollution level (urban of low and high traffic, residential, and postindustrial sites) after 60 days of exposure. Samples collected from high traffic sites and postindustrial site were found to have high contents of elements than residential sites and one of low traffic urban site. The principle component analysis (PCA) and correlation analysis provide important information about the potential sources of the elements in spider webs. Two contamination sources were identified: road traffic emissions and industrial. This was a first-time ever attempt to use webs for biomonitoring of small-scale distribution of airborne major and trace elements in the city of Wrocław.

  19. Attention bias modification in specific fears: Spiders versus snakes.

    Science.gov (United States)

    Luo, Xijia; Ikani, Nessa; Barth, Anja; Rengers, Lea; Becker, Eni; Rinck, Mike

    2015-12-01

    Attention Bias Modification (ABM) is used to manipulate attention biases in anxiety disorders. It has been successful in reducing attention biases and anxious symptoms in social anxiety and generalized anxiety, but not yet in specific fears and phobias. We designed a new version of the dot-probe training task, aiming to train fearful participants' attention away from or towards pictures of threatening stimuli. Moreover, we studied whether the training also affected participants' avoidance behavior and their physical arousal upon being confronted with a real threat object. In Experiment 1, students with fear of spiders were trained. We found that the attention manipulation was successful, but the training failed to affect behavior or arousal. In Experiment 2, the same procedure was used on snake-fearful students. Again, attention was trained in the expected directions. Moreover, participants whose attention had been trained away from snakes showed lower physiological arousal upon being confronted with a real snake. The study involved healthy students with normal distribution of the fear of spider/snake. Future research with clinical sample could help with determining the generalizability of the current findings. The effect of ABM on specific phobia is still in question. The finding in the present study suggested the possibility to alter attentional bias with a dot-probe task with general positive stimuli and this training could even affect the behavior while encountering a real threat. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Representatives of Spider Families (Arachnida: Araneae in Experimental Plots of Physic Nut Plantations (Jatropha curcas L. in Kampaeng Saen Campus of Kasetsart University, Thailand

    Directory of Open Access Journals (Sweden)

    Ondřej Košulič

    2015-01-01

    Full Text Available This paper makes a faunistic contribution to knowledge of the spider family composition in the experimental research plots of Kasetsart University in Thailand (Kampaeng Saen Campus, Nakhon Pathom province. Spider families were investigated both on the foliage and on the ground in physic nut plantations (Jatropha curcas L.. Ground dwelling spiders were collected by pitfall traps while foliage spiders were sampled by sweeping and hand collecting. In total, 655 spider specimens were collected and identified as belonging to 17 families. The dominant ground dwelling spider families were Lycosidae (50, 1% and Gnaphosidae (5, 3% while the dominant foliage spider families were Oxyopidae (14, 4% and Salticidae (8, 4%. We found that significant determinant of spider diversity and abundance was vegetation and foliage coverage which affect number of spider families throughout the investigated area.

  1. Tests for attraction to prey and predator avoidance by chemical cues in spiders of the beech forest floor

    Directory of Open Access Journals (Sweden)

    Wetter, Melissa B.

    2012-07-01

    Full Text Available Spiders leave draglines, faeces and other secretions behind when traveling through their microhabitat. The presence of these secretions may unintentionally inform other animals, prey as well as predators, about a recent and possible current predation risk or food availability. For a wolf spider, other spiders including smaller conspecifics, form a substantial part of their prey, and larger wolf spiders, again including conspecifics, are potential predators. We tested two hypotheses: that large wolf spiders may locate patches of potential spider prey through the presence of silk threads and/or other secretions; and that prey spiders may use secretions from large wolf spiders to avoid patches with high predation risk. We used large (subadult or adult Pardosa saltans to provide predator cues and mixed dwarf spiders or small (juvenile P. saltans to provide prey cues. Subadult wolf spiders were significantly attracted to litter contaminated by dwarf spiders or small conspecifics after 6 hours but no longer after 24 hours. In contrast, neither dwarf spiders nor small P. saltans showed significant avoidance of substrate contaminated by adult P. saltans. However, small P. saltans showed different activity patterns on the two substrates. The results indicate that wolf spiders are able to increase the efficiency of foraging by searching preferentially in patches with the presence of intraguild prey. The lack of a clear patch selection response of the prey in spite of a modified activity pattern may possibly be associated with the vertical stratification of the beech litter habitat: the reduced volume of spaces in the deeper layers could make downward rather than horizontal movement a fast and safe tactic against a large predator that cannot enter these spaces.

  2. Stochastic prey arrivals and crab spider giving-up times: simulations of spider performance using two simple "rules of thumb".

    Science.gov (United States)

    Kareiva, Peter; Morse, Douglass H; Eccleston, Jill

    1989-03-01

    We compared the patch-choice performances of an ambush predator, the crab spider Misumena vatia (Thomisidae) hunting on common milkweed Asclepias syriaca (Asclepiadaceae) umbles, with two stochastic rule-of-thumb simulation models: one that employed a threshold giving-up time and one that assumed a fixed probability of moving. Adult female Misumena were placed on milkweed plants with three umbels, each with markedly different numbers of flower-seeking prey. Using a variety of visitation regimes derived from observed visitation patterns of insect prey, we found that decreases in among-umbel variance in visitation rates or increases in overall mean visitation rates reduced the "clarity of the optimum" (the difference in the yield obtained as foraging behavior changes), both locally and globally. Yield profiles from both models were extremely flat or jagged over a wide range of prey visitation regimes; thus, differences between optimal and "next-best" strategies differed only modestly over large parts of the "foraging landscape". Although optimal yields from fixed probability simulations were one-third to one-half those obtained from threshold simulations, spiders appear to depart umbels in accordance with the fixed probability rule.

  3. Review the role of terminal domains during storage and assembly of spider silk proteins.

    Science.gov (United States)

    Eisoldt, Lukas; Thamm, Christopher; Scheibel, Thomas

    2012-06-01

    Fibrous proteins in nature fulfill a wide variety of functions in different structures ranging from cellular scaffolds to very resilient structures like tendons and even extra-corporal fibers such as silks in spider webs or silkworm cocoons. Despite their different origins and sequence varieties many of these fibrous proteins share a common building principle: they consist of a large repetitive core domain flanked by relatively small non-repetitive terminal domains. Amongst protein fibers, spider dragline silk shows prominent mechanical properties that exceed those of man-made fibers like Kevlar. Spider silk fibers assemble in a spinning process allowing the transformation from an aqueous solution into a solid fiber within milliseconds. Here, we highlight the role of the non-repetitive terminal domains of spider dragline silk proteins during storage in the gland and initiation of the fiber assembly process. Copyright © 2011 Wiley Periodicals, Inc.

  4. Contamination and Harm Relevant UCS-Expectancy Bias in Spider Phobic Individuals : Influence of Treatment

    NARCIS (Netherlands)

    van Overveld, Mark; de Jong, Peter J.; Huijding, Jorg; Peters, Madelon L.

    2010-01-01

    Phobic individuals expect aversive UCS's following encounters with phobic stimuli. Previous research using a thought-experiment procedure showed that contamination rather than harm-related outcome expectancies differentiated best between high and low spider fearful undergraduates. This study

  5. Intersexual Trophic Niche Partitioning in an Ant-Eating spider (Araneae: Zodariidae)

    DEFF Research Database (Denmark)

    Pekár, Stanislav; Martisová, Martina; Bilde, T.

    2011-01-01

    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...

  6. Mediterranean Recluse Spider, Loxosceles rufescens (Araneae: Sicariidae from Charkhab Cave, Southern Iran

    Directory of Open Access Journals (Sweden)

    Saber Sadeghi

    2017-04-01

    Full Text Available Background: The best-known dangerous spiders belong to the six genera. The genus Loxosceles or violin spiders are well known for their ability to cause skin necrosis or loxoscelism. All Loxosceles species have medical im­portance due to their necrotizing venom. The present article reports the occurrence of L. rufescens in Charkhab Cave, south of Iran (Larestan.Methods: The specimens were collected from the Charkhab Cave using handling forceps, paintbrush and aspirator and preserved in 96% ethanol.Results: Loxosceles rufescens, a medically important spider, is recorded from Charkhab Cave in Fars Province (southwest of Iran. Identification of L. rufescens was performed based on external morphology and the features of male genitalia.Conclusion: Presence of L. rufescens in south of Iran especially in a cave confirmed that this species is a widely distributed species in Iran. Therefore, cavers or cave visitors should be aware of this poisonous spider in caves.

  7. Blood phobia and spider phobia: two specific phobias with different autonomic cardiac modulations.

    Science.gov (United States)

    Sarlo, Michela; Palomba, Daniela; Angrilli, Alessandro; Stegagno, Luciano

    2002-09-01

    Cardiac reactions to two fear-related and one control film were compared in individuals high in spider or blood/injury fear. Twelve subjects in each phobic group were selected on the basis of their scores in the Spider or Mutilation Questionnaires and a semi-structured interview. Cardiac responses and self-reported affective ratings to the films were investigated. Sympathetic and parasympathetic cardiac influences were indexed by T-wave amplitude and respiratory sinus arrhythmia measured during film viewing. Basal parasympathetic cardiac control was also assessed during a paced breathing task. Results indicate differential autonomic modulation of cardiac responses for blood and spider phobics. Although each group reacted with marked cardiac activation to its feared stimulus, a sympathetic increase followed by withdrawal over time was found in blood phobics. Greater vagal tone at rest was present in blood phobics compared with spider phobics.

  8. Epigeic Spiders from Lowland Oak Woodlands in the South Moravia Region (Czech Republic

    Directory of Open Access Journals (Sweden)

    Kamila Surovcová

    2017-01-01

    Full Text Available This paper presents spider faunistics from abandoned coppice oak forest stands located along the South Moravia region. Spiders were collected from May to July 2012 by pitfall trapping at eight different localities. We collected 1945 adult spiders representing 20 families, 53 genera, and 90 species. More than one-third of all the species are known to be xerothermophilous with ecological restrictions to open and partly shaded habitats such as forest-steppe and sparse forests which belong to endangered habitats along central Europe. The most abundant species were Pardosa alacris, P. lugubris and Arctosa lutetiana from the family Lycosidae. In the surveyed area, 24 species were found listed in the Red List of Threatened Species in the Czech Republic (CR – 1 species, EN – 2 species, VU – 15 species, LC – 6 species. In general, we discovered a substantially diversified spider community with a large presence of rare and endangered species characteristic for open and xeric habitats.

  9. Toxicity of poison from spider Nephila sp. to Aëdes aegypti L. larvae

    Directory of Open Access Journals (Sweden)

    YAYAN SANJAYA

    2006-04-01

    Full Text Available A research about the toxicity of poison from spider Nephila sp. unto larvae of Aëdes aegypti L. had been done. The objectives of this research were to get the information about the toxicity of poison from spider Nephila sp. into larvae A. aegypti. The experiment method of this research was using Randomized Complete Block Design. This experiment used all of four instars of A. aegypti larvae. The experiment of each instar had been done with six treatments of the lethal concentration from spiders poison. Those six treatments were 1%, 10%, 25%, 50%, 75% and 100%. Each treatment had four replications. The result of this research showed that poison from spider Nephila sp. is toxic unto the larvae of A. aegypti. The average of lethal concentration for the first instar is 13.11%, for the second instar is 28.16%, for the third instar is 41.46% and for the fourth instar is 63.09%.

  10. Horizontally transferred fungal carotenoid genes in the two-spotted spider mite Tetranychus urticae

    National Research Council Canada - National Science Library

    Altincicek, Boran; Kovacs, Jennifer L; Gerardo, Nicole M

    2012-01-01

    ... that were acquired via horizontal gene transfer from fungi. Our search of available animal transcripts revealed the presence of two related genes in the two-spotted spider mite Tetranychus urticae...

  11. Physicochemical Property Variation in Spider Silk: Ecology, Evolution, and Synthetic Production.

    Science.gov (United States)

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

    2017-01-31

    The unique combination of great stiffness, strength, and extensibility makes spider major ampullate (MA) silk desirable for various biomimetic and synthetic applications. Intensive research on the genetics, biochemistry, and biomechanics of this material has facilitated a thorough understanding of its properties at various levels. Nevertheless, methods such as cloning, recombination, and electrospinning have not successfully produced materials with properties as impressive as those of spider silk. It is nevertheless becoming clear that silk properties are a consequence of whole-organism interactions with the environment in addition to genetic expression, gland biochemistry, and spinning processes. Here we assimilate the research done and assess the techniques used to determine distinct forms of spider silk chemical and physical property variability. We suggest that more research should focus on testing hypotheses that explain spider silk property variations in ecological and evolutionary contexts.

  12. Task specialization in two social spiders, Stegodyphus sarasinorum (Eresidae) and Anelosimus eximius (Theridiidae)

    DEFF Research Database (Denmark)

    Settepani, Virginia; Grinsted, Lena; Pedersen, Jørgen Granfeldt

    2013-01-01

    questions: Do individual spiders vary consistently in their propensity to engage in prey attack? Are individual spiders' propensities to engage in web maintenance behaviour influenced by their previous engagement in prey attack? Interestingly, we found that both species showed some degree of task......Understanding the social organization of group-living organisms is crucial for the comprehension of the underlying selective mechanisms involved in the evolution of cooperation. Division of labour and caste formation is restricted to eusocial organisms, but behavioural asymmetries and reproductive...... skew is common in other group-living animals. Permanently, social spiders form highly related groups with reproductive skew and communal brood care. We investigated task differentiation in nonreproductive tasks in two permanently and independently derived social spider species asking the following...

  13. 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.

  14. The Effect of Wind Exposure on the Web Characteristics of a Tetragnathid Orb Spider.

    Science.gov (United States)

    Tew, Nicholas; Hesselberg, Thomas

    2017-01-01

    Studies on spiders in their natural habitats are necessary for determining the full range of plasticity in their web-building behaviour. Plasticity in web design is hypothesised to be important for spiders building in habitats where environmental conditions cause considerable web damage. Here we compared web characteristics of the orb spider Metellina mengei (Araneae, Tetragnathidae) in two different forest habitats differing in their wind exposure. We found a notable lack of differences in web geometry, orientation and inclination between webs built along an exposed forest edge and those built inside the forest, despite marked differences in wind speed. This suggests that M. mengei did not exhibit web-building plasticity in response to wind in the field, contrasting with the findings of laboratory studies on other species of orb spiders. Instead, differences in prey capture and wind damage trade-offs between habitats may provide an explanation for our results, indicating that different species employ different strategies to cope with environmental constraints.

  15. 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 escape...

  16. Three new species of mygalomorph and filistatid spiders from Iran (Araneae, Cyrtaucheniidae, Nemesiidae and Filistatidae)

    OpenAIRE

    Marusik, Yuri M.; Alireza Zamani; Omid Mirshamsi

    2014-01-01

    Abstract Three new spider species are described from Iran: Anemesia koponeni sp. n. (?, Cyrtaucheniidae ); Raveniola mazandaranica sp. n. (?, Nemesiidae ) and Sahastata sinuspersica sp. n. (?, Filistatidae ). Cyrtaucheniidae and Sahastata Benoit, 1968 are reported from Iran for the fisrt time.

  17. Three new species of mygalomorph and filistatid spiders from Iran (Araneae, Cyrtaucheniidae, Nemesiidae and Filistatidae).

    Science.gov (United States)

    Marusik, Yuri M; Zamani, Alireza; Mirshamsi, Omid

    2014-01-01

    Three new spider species are described from Iran: Anemesiakoponeni sp. n. (♂, Cyrtaucheniidae); Raveniolamazandaranica sp. n. (♂, Nemesiidae) and Sahastatasinuspersica sp. n. (♀, Filistatidae). Cyrtaucheniidae and Sahastata Benoit, 1968 are reported from Iran for the fisrt time.

  18. Effects of the Spider Venom on proliferation of Human Lung Adenocarcinoma Cell A549

    Directory of Open Access Journals (Sweden)

    Zengxiang HU

    2010-10-01

    Full Text Available Background and objective The spider venom may inspire new drugs to treat cancer. The aim of this study is to investigate the effects and mechanisms of spider venom on lung adenocarcinoma cell A549. Methods The proliferation of lung adenocarcinoma A549 cells was detected by MTT. The apoptosis rate was observed with MTT assay and flow cytometer. The activity of catalase was detected by colorimetry. The malondialdehyde (MDA content was determined by improved thiobarbituric acid fluorometric method. The expression of P38MAPK protein was analyzed with Western blot. Results Spider venom can remarkably inhibite the proliferation of lung adenocarcinoma A549 cells, increased activity of catalase and MDA content, down-regulated expression of P38MAPK compared with the control group. Conclusion The reduced proliferation of lung adenocarcinoma A549 cells by spider venom is may be associated with the increased of activity of catalase and MDA content and decreased expression of P38MAPK.

  19. Severe systemic reaction to Loxosceles reclusa spider bites in a pediatric population.

    Science.gov (United States)

    Elbahlawan, Lama M; Stidham, Gregory L; Bugnitz, Mark C; Storgion, Stephanie A; Quasney, Michael W

    2005-03-01

    To report 6 children who had severe systemic reaction after spider bites requiring pediatric intensive care unit admission and to describe their clinical presentation, hospital course, and outcome. A retrospective analysis was done to identify patients presenting with brown recluse spider bites. Charts of children admitted to the intensive care unit were reviewed. Six previously healthy African-American children, aged 3 to 15 years, with brown recluse spider bites were admitted to the pediatric intensive care unit. All had fever, jaundice, and evidence of hemolytic anemia. Four of 6 children had hypotension. One child developed mental status changes, acute renal failure secondary to rhabdomyolysis, and hyperkalemia and required emergent hemodialysis. All children fully recovered. Although most cases of brown recluse spider bites are benign requiring no intervention, severe systemic reactions may occur in the pediatric population resulting in admission to the pediatric intensive care unit. These systemic reactions may include hemolytic anemia, hypotension, and renal failure.

  20. 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...

  1. 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.

  2. Whiteflies Interfere with Indirect Plant Defense against Spider Mites in Lima Bean

    National Research Council Canada - National Science Library

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

    2009-01-01

    .... Here, we report the interference by a phloem-feeding insect, the whitefly Bemisia tabaci, with indirect plant defenses induced by spider mites (Tetranychus urticae) in Lima bean (Phaseolus lunatus) plants...

  3. Sexual size dimorphism predicts the frequency of sexual cannibalism within and among species of spiders.

    Science.gov (United States)

    Wilder, Shawn M; Rypstra, Ann L

    2008-09-01

    Sexual cannibalism varies widely among spiders, but no general evolutionary hypothesis has emerged to explain its distribution across taxa. Sexual size dimorphism (SSD) also varies widely among spiders and could affect the vulnerability of males to cannibalistic attacks by females. We tested for a relationship between SSD and sexual cannibalism within and among species of spiders, using a broad taxonomic data set. For most species, cannibalism was more likely when males were much smaller than females. In addition, using phylogenetically controlled and uncontrolled analyses, there was a strong positive relationship between average SSD of a species and the frequency of sexual cannibalism. This is the first evidence that the degree of size difference between males and females is related to the phylogenetic distribution of sexual cannibalism among a broad range of spiders.

  4. Visual working memory and threat monitoring: Spider fearfuls show disorder-specific change detection.

    Science.gov (United States)

    Reinecke, Andrea; Becker, Eni S; Rinck, Mike

    2010-08-01

    Previous studies of biased information processing in anxiety addressed biases of attention and memory, but little is known about the processes taking place between them: visual working memory (VWM) and monitoring of threat. We investigated these processes with a change detection paradigm. In Experiment 1, spider fearfuls (SF) and non-anxious controls (NAC) judged two subsequently presented displays as same or different. The displays consisted of several pictures, one of which could depict a spider. In Experiment 2, SF and NAC, both without snake fear, were tested with displays including either a spider or a snake image to determine the material-specificity of biased VWM. Both groups showed increased change detection for threat images. This effect was significantly stronger in SF, for spider images only, indicating a threat-specific VWM bias. Thus, contrary to the assumptions made by most cognitive models of anxiety, an explicit memory bias was found. Copyright 2010 Elsevier Ltd. All rights reserved.

  5. Detritus decorations of an orb-weaving spider, Cyclosa mulmeinensis (Thorell): for food or camouflage?

    Science.gov (United States)

    Tan, Eunice J; Li, Daiqin

    2009-06-01

    Many species of the orb-web spider genus Cyclosa often adorn their webs with decorations of prey remains, egg sacs and/or plant detritus, termed ;detritus decorations'. These detritus decorations have been hypothesised to camouflage the spider from predators or prey and thus reduce predation risk or increase foraging success. In the present study, we tested these two alternative hypotheses simultaneously using two types of detritus decorations (prey remain and egg sac) built by Cyclosa mulmeinensis (Thorell). By monitoring the possible responses of predators to spiders on their webs with and without decorations in the field, we tested whether web decorations would reduce the mortality of spiders. Wasp predators were observed to fly in the vicinity of webs with decorations slightly more often than in the vicinity of webs without decorations but there were very few attacks on spiders by wasps. By comparing the insect interception rates of webs with and without decorations in the field, we tested whether web decorations would increase the foraging success. Webs decorated with prey remains or egg sacs intercepted more insects than those without in the field. By calculating colour contrasts of both prey-remain and egg-sac decorations against spiders viewed by bird (blue tits) and hymenopteran (e.g. wasps) predators as well as hymenopteran (bees) prey, we showed that C. mulmeinensis spiders on webs with egg-sac decorations were invisible to both hymenopteran prey and predators and bird predators over short and long distances. While spiders on webs with prey-remain decorations were invisible to both hymenopterans and birds over short distances, spiders on webs with prey-remain decorations were visible to both predators and prey over long distances. Our results thus suggest that decorating webs with prey remains and egg sacs in C. mulmeinensis may primarily function as camouflage to conceal the spider from insects rather than as prey attractants, possibly contributing to

  6. Storage buildings and greenhouses as stepping stones for non-native, potentially invasive spiders (Araneae – a baseline study in Basel, Switzerland

    Directory of Open Access Journals (Sweden)

    Hänggi, Ambros

    2016-04-01

    Full Text Available Transportation of goods via land, sea or air causes a dissemination of species on a global scale. In central Europe species that are associated with fruit, vegetables and/or buildings are suspected to be imported and potentially build up populations in the following four categories of buildings: I greenhouses, garden centres, flower shops and flower wholesale stores, II storage buildings and logistic centres, III botanical gardens and zoos and IV touristic hotspots. During this research 20 such localities in and around Basel were investigated by means of visual searching. 340 adult spider individuals were collected, representing 37 species and 15 families. Three were first records for Switzerland. Eight species were not published before for the region of Basel even if six of these were already known in private, not published collections – partly going back to the 1930s. Our investigation shows that the interpretation of the spread and invasion of species needs good published knowledge about the actual status of our fauna which, especially for synanthropic spiders, is not the case. We therefore urge everybody to publish all knowledge about faunistics even for so-called common species.

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

    Directory of Open Access Journals (Sweden)

    Buchholz, Sascha

    2008-07-01

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

  8. A checklist of the spiders (Araneae) of the Chornohora Mountain massif (the Ukrainian Carpathians)

    OpenAIRE

    Hirna, Anna; Gnelitsa, Valery; Zhukovets, Evgeni

    2016-01-01

    The present checklist of spiders native to the Chornohora Mts of the Ukrainian Carpathians is based both on literature-derived data and on material collected by the authors in 1999, 2006 and 2011-2014. The majority of these studies (approximately 80 %) were conducted in the upper montane forests, subalpine and alpine levels on the slopes of the main ridge and adjacent spurs and mountains. The study also covers glacial cirques and river valleys. A few spiders were collected from local villages...

  9. On Graceful Spider Graphs with at Most Four Legs of Lengths Greater than One

    Directory of Open Access Journals (Sweden)

    A. Panpa

    2016-01-01

    Full Text Available A graceful labeling of a tree T with n edges is a bijection f:V(T→{0,1,2,…,n} such that {|f(u-f(v|:uv∈E(T} equal to {1,2,…,n}. A spider graph is a tree with at most one vertex of degree greater than 2. We show that all spider graphs with at most four legs of lengths greater than one admit graceful labeling.

  10. Towards a new generation of fibre-optic chemical sensors based on spider silk threads

    OpenAIRE

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

    2016-01-01

    A spider uses up to seven different types of silk, all having specific functions, to build its web. For scientists, native silk - directly extracted from spiders - is a tough, biodegradable and biocompatible thread used mainly for tissue engineering and textile applications. Blessed with outstanding optical properties, this protein strand can also be used as an optical fibre and is, moreover, intrinsically sensitive to chemical compounds. In this communication, a pioneering proof-of-concept e...

  11. Biochemical and structural characterization of a novel arginine kinase from the spider Polybetes pythagoricus

    OpenAIRE

    Aldana Laino; Alonso A. Lopez-Zavala; Karina D. Garcia-Orozco; Jesus S. Carrasco-Miranda; Marianela Santana; Vivian Stojanoff; Rogerio R. Sotelo-Mundo; Carlos Fernando Garcia

    2017-01-01

    Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Arg...

  12. The richness and paucity of the spider fauna of the Belgian coast

    OpenAIRE

    Maelfait, J.-P.; Baert, L; Bonte, D.; Hendrickx, F.

    2000-01-01

    A comparison is made between the spider species composition of twelve sandy natural areas in Flanders along a gradient from the coast dunes and salt marshes in the west to the large heathland areas in the east. All these natural areas have large numbers of rare and threatened species. The relative paucity in spider species in coastal reserves is caused by the lack of species bound to ombrotrophic Sphagnum bog vegetation and to wet oligotrophic grasslands.

  13. Tx2-6 toxin of the Phoneutria nigriventer spider potentiates rat erectile function.

    OpenAIRE

    Nunes, Kenia Pedrosa; Gonçalves, Andrey Christian da Costa; Lanza, Luciana Franco; Côrtes, Steyner de França; Cordeiro, Marta do Nascimento; Michael, Richardson; Pimenta, Adriano Monteiro de Castro; Webb, R. Clinton; Garcia, Maria Elena de Lima Perez

    2008-01-01

    The venom of the spider Phoneutria nigriventer contains several toxins that have bioactivity in mammals and insects. Accidents involving humans are characterized by various symptoms including penile erection. Here we investigated the action of Tx2-6, a toxin purified from the P. nigriventer spider venom that causes priapism in rats and mice. Erectile function was evaluated through changes in intracavernosal pressure/mean arterial pressure ratio (ICP/MAP) during electrical stimulation of the m...

  14. Tx2-6 toxin of the Phoneutria nigriventer spider potentiates rat erectile function☆

    OpenAIRE

    Nunes, K.P.; Costa-Gonçalves, A.; Lanza, L.F.; Cortes, S.F.; Cordeiro, M.N.; Richardson, M.; Pimenta, A. M. C.; Webb, R. C.; Leite, R.; LIMA, M. E. de

    2008-01-01

    The venom of the spider Phoneutria nigriventer contains several toxins that have bioactivity in mammals and insects. Accidents involving humans are characterized by various symptoms including penile erection. Here we investigated the action of Tx2-6, a toxin purified from the P. nigriventer spider venom that causes priapism in rats and mice. Erectile function was evaluated through changes in intracavernosal pressure/mean arterial pressure ratio (ICP/MAP) during electrical stimulation of the m...

  15. 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.

  16. Record breaking achievements by spiders and the scientists who study them.

    Science.gov (United States)

    Mammola, Stefano; Michalik, Peter; Hebets, Eileen A; Isaia, Marco

    2017-01-01

    Organismal biology has been steadily losing fashion in both formal education and scientific research. Simultaneous with this is an observable decrease in the connection between humans, their environment, and the organisms with which they share the planet. Nonetheless, we propose that organismal biology can facilitate scientific observation, discovery, research, and engagement, especially when the organisms of focus are ubiquitous and charismatic animals such as spiders. Despite being often feared, spiders are mysterious and intriguing, offering a useful foundation for the effective teaching and learning of scientific concepts and processes. In order to provide an entryway for teachers and students-as well as scientists themselves-into the biology of spiders, we compiled a list of 99 record breaking achievements by spiders (the "Spider World Records"). We chose a world-record style format, as this is known to be an effective way to intrigue readers of all ages. We highlighted, for example, the largest and smallest spiders, the largest prey eaten, the fastest runners, the highest fliers, the species with the longest sperm, the most venomous species, and many more. We hope that our compilation will inspire science educators to embrace the biology of spiders as a resource that engages students in science learning. By making these achievements accessible to non-arachnologists and arachnologists alike, we suggest that they could be used: (i) by educators to draw in students for science education, (ii) to highlight gaps in current organismal knowledge, and (iii) to suggest novel avenues for future research efforts. Our contribution is not meant to be comprehensive, but aims to raise public awareness on spiders, while also providing an initial database of their record breaking achievements.

  17. 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...

  18. Effects of the Spider Venom on proliferation of Human Lung Adenocarcinoma Cell A549

    OpenAIRE

    Zengxiang HU; Du, Yulei; Quanxi LIU; Wang, Yuan

    2010-01-01

    Background and objective The spider venom may inspire new drugs to treat cancer. The aim of this study is to investigate the effects and mechanisms of spider venom on lung adenocarcinoma cell A549. Methods The proliferation of lung adenocarcinoma A549 cells was detected by MTT. The apoptosis rate was observed with MTT assay and flow cytometer. The activity of catalase was detected by colorimetry. The malondialdehyde (MDA) content was determined by improved thiobarbituric acid fluorometric met...

  19. Record breaking achievements by spiders and the scientists who study them

    Directory of Open Access Journals (Sweden)

    Stefano Mammola

    2017-10-01

    Full Text Available Organismal biology has been steadily losing fashion in both formal education and scientific research. Simultaneous with this is an observable decrease in the connection between humans, their environment, and the organisms with which they share the planet. Nonetheless, we propose that organismal biology can facilitate scientific observation, discovery, research, and engagement, especially when the organisms of focus are ubiquitous and charismatic animals such as spiders. Despite being often feared, spiders are mysterious and intriguing, offering a useful foundation for the effective teaching and learning of scientific concepts and processes. In order to provide an entryway for teachers and students—as well as scientists themselves—into the biology of spiders, we compiled a list of 99 record breaking achievements by spiders (the “Spider World Records”. We chose a world-record style format, as this is known to be an effective way to intrigue readers of all ages. We highlighted, for example, the largest and smallest spiders, the largest prey eaten, the fastest runners, the highest fliers, the species with the longest sperm, the most venomous species, and many more. We hope that our compilation will inspire science educators to embrace the biology of spiders as a resource that engages students in science learning. By making these achievements accessible to non-arachnologists and arachnologists alike, we suggest that they could be used: (i by educators to draw in students for science education, (ii to highlight gaps in current organismal knowledge, and (iii to suggest novel avenues for future research efforts. Our contribution is not meant to be comprehensive, but aims to raise public awareness on spiders, while also providing an initial database of their record breaking achievements.

  20. Mechanisms Involved in the Nociception Triggered by the Venom of the Armed Spider Phoneutria nigriventer

    OpenAIRE

    Camila Gewehr; Sara Marchesan Oliveira; Mateus Fortes Rossato; Gabriela Trevisan; Gerusa Duarte Dalmolin; Flávia Karine Rigo; Célio José de Castro Júnior; Marta Nascimento Cordeiro; Juliano Ferreira; Gomez, Marcus V.

    2013-01-01

    BACKGROUND: The frequency of accidental spider bites in Brazil is growing, and poisoning due to bites from the spider genus Phoneutria nigriventer is the second most frequent source of such accidents. Intense local pain is the major symptom reported after bites of P. nigriventer, although the mechanisms involved are still poorly understood. Therefore, the aim of this study was to identify the mechanisms involved in nociception triggered by the venom of Phoneutria nigriventer (PNV). METHODOLOG...

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

    Science.gov (United States)

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

    2017-01-01

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

  2. 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

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

    Directory of Open Access Journals (Sweden)

    Vera Oldrati

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

  4. 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

  5. First report of brown widow spider sightings in Peninsular Malaysia and notes on its global distribution.

    Science.gov (United States)

    Muslimin, Mustakiza; Wilson, John-James; Ghazali, Amir-Ridhwan M; Braima, Kamil A; Jeffery, John; Wan-Nor, Fitri; Alaa-Eldin, Mohamed E; Mohd-Zin, Siti-Waheeda; Wan-Yusoff, Wan S; Norma-Rashid, Yusoff; Lau, Yee L; Rohela, Mahmud; Abdul-Aziz, Noraishah M

    2015-01-01

    The brown widow spider (Latrodectus geometricus Koch, 1841) has colonised many parts of the world from its continent of origin, Africa. By at least 1841, the species had successfully established populations in South America and has more recently expanded its range to the southern states of North America. This highly adaptable spider has been far more successful in finding its niche around the world than its famous cousins, the black widow, Latrodectus mactans, found in the south-eastern states of North America, and the red-back, Latrodectus hasselti, found mostly in Australia, New Zealand and Japan. We performed an extensive web search of brown widow sightings and mapped the location of each sighting using ArcGIS. Specimens reputedly of the species L. geometricus were collected at three localities in Peninsular Malaysia. The spiders were identified and documented based on an examination of morphological characteristics and DNA barcoding. The spiders found in Peninsular Malaysia were confirmed to be Latrodectus geometricus based on their morphological characteristics and DNA barcodes. We recorded 354 sightings of the brown widow in 58 countries, including Peninsular Malaysia. Reports from the Americas and the Far East suggest a global-wide invasion of the brown widow spider. Herein we report the arrival of the brown widow spider in Peninsular Malaysia and provide notes on the identification of the species and its recently expanded range.

  6. Social makes smart: rearing conditions affect learning and social behaviour in jumping spiders.

    Science.gov (United States)

    Liedtke, J; Schneider, J M

    2017-11-01

    There is a long-standing debate as to whether social or physical environmental aspects drive the evolution and development of cognitive abilities. Surprisingly few studies make use of developmental plasticity to compare the effects of these two domains during development on behaviour later in life. Here, we present rearing effects on the development of learning abilities and social behaviour in the jumping spider Marpissa muscosa. These spiders are ideally suited for this purpose because they possess the ability to learn and can be reared in groups but also in isolation without added stress. This is a critical but rarely met requirement for experimentally varying the social environment to test its impact on cognition. We split broods of spiders and reared them either in a physically or in a socially enriched environment. A third group kept under completely deprived conditions served as a 'no-enrichment' control. We tested the spiders' learning abilities by using a modified T-maze. Social behaviour was investigated by confronting spiders with their own mirror image. Results show that spiders reared in groups outperform their conspecifics from the control, i.e. 'no-enrichment', group in both tasks. Physical enrichment did not lead to such an increased performance. We therefore tentatively suggest that growing up in contact with conspecifics induces the development of cognitive abilities in this species.

  7. Sparing spiders: faeces as a non-invasive source of DNA.

    Science.gov (United States)

    Sint, Daniela; Thurner, Isabella; Kaufmann, Ruediger; Traugott, Michael

    2015-01-01

    Spiders are important arthropod predators in many terrestrial ecosystems, and molecular tools have boosted our ability to investigate this taxon, which can be difficult to study with conventional methods. Nonetheless, it has typically been necessary to kill spiders to obtain their DNA for molecular applications, especially when studying their diet. We successfully tested the novel approach of employing spider faeces as a non-invasive source of DNA for species identification and diet analysis. Although the overall concentration of DNA in the samples was very low, consumer DNA, suitable for species identification, was amplified from 84% of the faecal pellets collected from lycosid spiders. Moreover, the most important prey types detected in the gut content of the lycosids were also amplified from the faecal samples. The ability to amplify DNA from spider faeces with specific and general primers suggests that this sample type can be used for diagnostic PCR and sequence-based species and prey identification such as DNA barcoding and next generation sequencing, respectively. These findings demonstrate that faeces provide a non-invasive alternative to full-body DNA extracts for molecular studies on spiders when killing or injuring the animal is not an option.

  8. 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.

  9. In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction.

    Directory of Open Access Journals (Sweden)

    Anne Steins

    Full Text Available Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial with outstanding mechanical properties and a slow degradation rate, as a potential scaffold for bladder reconstruction by studying the cellular response of primary bladder cells to this biomaterial. We demonstrate that spider silk without any additional biological coating supports adhesion and growth of primary human urothelial cells (HUCs, which are multipotent bladder cells able to differentiate into the various epithelial layers of the bladder. HUCs cultured on spider silk did not show significant changes in the expression of various epithelial-to-mesenchymal transition and fibrosis associated genes, and demonstrated only slight reduction in the expression of adhesion and cellular differentiation genes. Furthermore, flow cytometric analysis showed that most of the silk-exposed HUCs maintain an undifferentiated immunophenotype. These results demonstrate that spider silk from the Nephila edulis spider supports adhesion, survival and growth of HUCs without significantly altering their cellular properties making this type of material a suitable candidate for being tested in pre-clinical models for bladder reconstruction.

  10. In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction

    Science.gov (United States)

    Steins, Anne; Dik, Pieter; Müller, Wally H.; Vervoort, Stephin J.; Reimers, Kerstin; Kuhbier, Jörn W.; Vogt, Peter M.; van Apeldoorn, Aart A.; Coffer, Paul J.; Schepers, Koen

    2015-01-01

    Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial with outstanding mechanical properties and a slow degradation rate, as a potential scaffold for bladder reconstruction by studying the cellular response of primary bladder cells to this biomaterial. We demonstrate that spider silk without any additional biological coating supports adhesion and growth of primary human urothelial cells (HUCs), which are multipotent bladder cells able to differentiate into the various epithelial layers of the bladder. HUCs cultured on spider silk did not show significant changes in the expression of various epithelial-to-mesenchymal transition and fibrosis associated genes, and demonstrated only slight reduction in the expression of adhesion and cellular differentiation genes. Furthermore, flow cytometric analysis showed that most of the silk-exposed HUCs maintain an undifferentiated immunophenotype. These results demonstrate that spider silk from the Nephila edulis spider supports adhesion, survival and growth of HUCs without significantly altering their cellular properties making this type of material a suitable candidate for being tested in pre-clinical models for bladder reconstruction. PMID:26689371

  11. 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.

  12. Intraindividual Behavioral Variability Predicts Foraging Outcome in a Beach-dwelling Jumping Spider.

    Science.gov (United States)

    Lichtenstein, James L L; Chism, Gregory T; Kamath, Ambika; Pruitt, Jonathan N

    2017-12-22

    Animal personality, defined as consistent differences between individuals in behavior, has been the subject of hundreds if not thousands of papers. However, little work explores the fitness consequences of variation in behavior within individuals, or intraindividual variability (IIV). We probe the effects of behavioral IIV on predator-prey interaction outcomes in beach-dwelling jumping spiders (Terralonus californicus). Prior studies have found that spiders with higher body condition (body mass relative to size) behave more variably. Thus, we hypothesized that jumping spider activity level IIV would relate positively to foraging performance. To address this, we tested for associations between activity IIV, average activity level, and two measures of foraging success in laboratory mesocosms: change in spider mass and the number of prey killed. Activity IIV positively correlated with the mass that spiders gained from prey, but not with the number of prey killed. This suggests that spiders with high IIV consumed a greater proportion of their prey or used less energy. Interestingly, average activity level (personality) predicted neither metric of foraging success, indicating that behavioral IIV can predict metrics of success that personality does not. Therefore, our findings suggest that IIV should be considered alongside personality in studies of predator-prey interactions.

  13. 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. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Glucocorticoids enhance in vivo exposure-based therapy of spider phobia.

    Science.gov (United States)

    Soravia, Leila M; Heinrichs, Markus; Winzeler, Livia; Fisler, Melanie; Schmitt, Wolfgang; Horn, Helge; Dierks, Thomas; Strik, Werner; Hofmann, Stefan G; de Quervain, Dominique J-F

    2014-05-01

    Preclinical and clinical studies indicate that the administration of glucocorticoids may promote fear extinction processes. In particular, it has been shown that glucocorticoids enhance virtual reality based exposure therapy of fear of heights. Here, we investigate whether glucocorticoids enhance the outcome of in vivo exposure-based group therapy of spider phobia. In a double blind, block-randomized, placebo-controlled, between-subject study design, 22 patients with specific phobia of spiders were treated with two sessions of in vivo exposure-based group therapy. Cortisol (20 mg) or placebo was orally administered 1 hr before each therapy session. Patients returned for a follow-up assessment one month after therapy. Exposure-based group therapy led to a significant decrease in phobic symptoms as assessed with the Fear of Spiders Questionnaire (FSQ) from pretreatment to immediate posttreatment and to follow-up. The administration of cortisol to exposure therapy resulted in increased salivary cortisol concentrations and a significantly greater reduction in fear of spiders (FSQ) as compared to placebo at follow-up, but not immediately posttreatment. Furthermore, cortisol-treated patients reported significantly less anxiety during standardized exposure to living spiders at follow-up than placebo-treated subjects. Notably, groups did not differ in phobia-unrelated state-anxiety before and after the exposure sessions and at follow-up. These findings indicate that adding cortisol to in vivo exposure-based group therapy of spider phobia enhances treatment outcome. © 2013 Wiley Periodicals, Inc.

  15. 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.

  16. Task specialization in two social spiders, Stegodyphus sarasinorum (Eresidae) and Anelosimus eximius (Theridiidae).

    Science.gov (United States)

    Settepani, V; Grinsted, L; Granfeldt, J; Jensen, J L; Bilde, T

    2013-01-01

    Understanding the social organization of group-living organisms is crucial for the comprehension of the underlying selective mechanisms involved in the evolution of cooperation. Division of labour and caste formation is restricted to eusocial organisms, but behavioural asymmetries and reproductive skew is common in other group-living animals. Permanently, social spiders form highly related groups with reproductive skew and communal brood care. We investigated task differentiation in nonreproductive tasks in two permanently and independently derived social spider species asking the following questions: Do individual spiders vary consistently in their propensity to engage in prey attack? Are individual spiders' propensities to engage in web maintenance behaviour influenced by their previous engagement in prey attack? Interestingly, we found that both species showed some degree of task specialization, but in distinctly different ways: Stegodyphus sarasinorum showed behavioural asymmetries at the individual level, that is, individual spiders that had attacked prey once were more likely to attack prey again, independent of their body size or hunger level. In contrast, Anelosimus eximius showed no individual specialization, but showed differentiation according to instar, where adult and subadult females were more likely to engage in prey attack than were juveniles. We found no evidence for division of labour between prey attack and web maintenance. Different solutions to achieve task differentiation in prey attack for the two species studied here suggest an adaptive value of task specialization in foraging for social spiders. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

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

    Directory of Open Access Journals (Sweden)

    Benjamin Eggs

    Full Text Available 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.

  18. The cost of fear: avoidant decision making in a spider gambling task.

    Science.gov (United States)

    Pittig, Andre; Brand, Matthias; Pawlikowski, Mirko; Alpers, Georg W

    2014-04-01

    Individuals with anxiety disorders typically avoid fear-relevant stimuli even if they miss potential rewards. However, few studies have accounted for such costs of fear-related avoidance in doing so. In this study, 51 spider fearful and 49 non-fearful participants completed the Spider Gambling Task, our modification of the Iowa Gambling Task, to investigate whether fear-relevant stimuli trigger avoidant decisions in the presence of potential rewards. In one version, advantageous choices were associated with pictures of spiders, whereas the same pictures were associated with disadvantageous choices in another version. Fearful participants generally avoided choices associated with pictures of spiders, which resulted in lower overall gains in the version with advantageous spider decks. Although this relative avoidance was sustained, fearful participants progressively approach more advantageous spider choices. These findings demonstrate that phobic fear results in irrational avoidant decisions which can result in considerable cost. Potential long-term rewards for approach may, however, diminish absolute avoidance behavior. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Effects of grassland succession on communities of orb-weaving spiders.

    Science.gov (United States)

    Richardson, M L; Hanks, L M

    2009-12-01

    Native grasslands are among the most imperiled of the North American ecosystems, but abandoned agricultural areas may provide suitable habitat for animal taxa that are endemic to grasslands. We studied how species diversity of orb-weaving spiders was influenced by secondary succession of a grassland plant community by monitoring the abundance and species diversity in study plots that were cultivated at 6-yr intervals and left uncultivated in the interim. We tested the hypothesis that local abundance and species diversity of spiders would be positively associated with time since cultivation because plant communities in older habitats would be more architecturally complex. Local abundance of spiders in general was not associated with time since cultivation, but abundance of Mangora gibberosa (Hentz) was positively associated with the abundance of perennial plants. Species richness and diversity of spiders also were positively associated with the abundance of perennial plants and reached a threshold a few years after cultivation. Species diversity of orb-weaving spiders seems to be strongly influenced by species composition of the plant community. Therefore, effective restoration of the structure and function of endemic communities of orb-weaving spiders may depend on preserving endemic grassland plant communities.

  20. Nutritional compound analysis and morphological characterization of spider plant (Cleome gynandra) - an African indigenous leafy vegetable.

    Science.gov (United States)

    Omondi, Emmanuel O; Engels, Christof; Nambafu, Godfrey; Schreiner, Monika; Neugart, Susanne; Abukutsa-Onyango, Mary; Winkelmann, Traud

    2017-10-01

    Spider plant is among the important indigenous African leafy vegetables having the potential to contribute to food and nutritional security in sub-Saharan Africa. The main objective of this study was to quantify the mineral concentration, to identify and quantify glucosinolates and flavonoids in spider plant and further to characterize spider plant entries using important morphological traits. Thirty spider plant entries from different African countries, comprising of farmers' cultivars, gene bank accessions and advanced lines were grown in a field experiment and harvested for leaves, stems, flowers and siliques at different developmental stages. Five plant types based on the stem and petiole colorations were identified. Significant genotypic differences were shown for all the morphological traits except for 100 seed weight and silique weight. High mineral concentrations in the leaf tissue were observed especially for potassium, calcium, magnesium, phosphorus, iron, manganese and zinc. The aliphatic 3-hydroxypropyl glucosinolate was the main glucosinolate detected in all tissues with the highest concentrations in the reproductive organs. Glycosides of quercetin, kaempferol and isorhamnetin were the main flavonoids. Isorhamnetin glycosides were detected in trace amounts in both, leaves and inflorescences, while quercetin and kaempferol glycosides were the dominant flavonoids in the leaves and inflorescences, respectively. This knowledge of beneficial nutrient contents is an incentive for promoting spider plant consumption for improved human health while the morphological diversity analysis will be important for the further development of the spider plant germplasm. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2015-08-01

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

  2. 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.

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

    Science.gov (United States)

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

    2009-12-15

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

  4. Contributions of detrital subsidies to aboveground spiders during secondary succession, revealed by radiocarbon and stable isotope signatures.

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    Haraguchi, Takashi F; Uchida, Masao; Shibata, Yasuyuki; Tayasu, Ichiro

    2013-04-01

    Prey subsidies originating from detritus add nutrients and energy to arboreal communities. Measurement of this subsidy is required in the understanding of how food web dynamics respond to changes in surrounding environments. Shrub spiders are one of the key predators involved in food web coupling. We evaluate the effects of potential changes in prey availabilities during secondary succession on the contribution of subsidy from detrital food webs to shrub spiders and how different spider feeding guilds used the subsidy of prey from detrital food webs. We measured the relative importance of the subsidy for the spider feeding guilds, using the ratios of stable isotopes of C (δ(13)C), and N (δ(15)N) and C isotope discrimination (Δ(14)C). Diet age was calculated from Δ(14)C values, because old diet ages of spiders indicate that the spiders consume prey from detrital food sources. Dominant aerial prey (Diptera) had a distinctively old diet age compared with arboreal prey, which indicates that aerial prey were subsidized from detrital food webs. Sit-and-wait spiders tended to have an older diet age than active hunting spiders, which indicates that sit-and-wait spiders depended more on subsidies. Diet age varied only slightly for spiders in stands of different ages, indicating that rates at which spiders use grazing and detrital prey are probably determined more by foraging strategies and not by stand age. A dominance of sit-and-wait predators will lead to higher detrital subsidy inputs in shrub habitats. This study highlights the effect of shrub spider community structure (feeding guild composition) on the volume of the subsidy received from the detrital food web.

  5. A three-dimensional model study of methanesulphonic acid to non sea salt sulphate ratio at mid and high-southern latitudes

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    E. Cosme

    2009-12-01

    Full Text Available The Antarctic and sub-Antarctic methanesulphonic acid (MSA to non sea salt sulphate (nssSO4 ratio is simulated with the Laboratoire de Météorologie Dynamique Atmospheric General Circulation Model including an atmospheric sulphur chemistry module. Spatial variations of the MSA/nssSO4 ratio in different regions have been suggested to be mostly dependent on temperature or sulphur source contributions. Its past variations in ice cores have been interpreted as related to the DMS precursor source location. Our model results are compared with available field measurements in the Antarctic and sub-Antarctic regions. This suggests that the MSA/nssSO4 ratio in the extra-tropical south hemisphere is mostly dependent on the relative importance of various DMS oxidation pathways. In order to evaluate the effect of a rapid conversion of dimethyl sulphoxide (DMSO into MSA, not implemented in the model, the MSA+DMSO to nssSO4 ratio is also discussed. Using this modified ratio, the model mostly captures the seasonal variations of MSA/nssSO4 at mid and high-southern latitudes. In addition, the model qualitatively reproduces the bell shaped meridional variations of the ratio, which is highly dependent on the adopted relative reaction rates for the DMS+OH addition and abstraction pathways, and on the assumed reaction products of the MSIA+OH reaction. MSA/nssSO4 ratio in Antarctic snow is fairly well reproduced except at the most inland sites characterized with very low snow accumulation rates. Our results also suggest that atmospheric chemistry plays an important role in the observed decrease of the ratio in snow between coastal regions and central Antarctica. The still insufficient understanding of the DMS oxidation scheme limits our ability to model the MSA/nssSO4 ratio. Specifically, reaction products of the MSIA+OH reaction should be better quantified, and the impact of a fast DMSO

  6. Spiders in Fauna Europaea: dual use of the database

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    Helsdingen, Peter J. van

    2012-07-01

    Full Text Available The history and current work of the project Fauna Europaea is outlined. The different sources used for building up the database and the efforts to keep it updated are described. Available models of national checklists are discussed and the ideal checklist is described. The double use of the database as a matrix behind the official site of Fauna Europaea – as well as a directly visible document on the website of the European Society of Arachnology – are indicated and the differences in transparency, links to literature sources, and facilities such as distribution maps and calculations of numbers of scores per species or of species per country are discussed. The future of the project is briefly outlined. The need for a European identification tool for spiders is stressed.

  7. Novel Compact Spider Microstrip Antenna with New Defected Ground Structure

    Science.gov (United States)

    Ghoname, R. S.; Mohamed, M. A.; Hennawy, A. El.

    2012-08-01

    Two novel Defected Ground Structures (DGS) were first proposed, which have better results than that of the dumbbell (published shape). Using the general model of DGS, its equivalent parameters were extracted. The two new proposed shapes of DGS were then used to design a novel compact spider microstrip antenna to minimize its area. The size of the developed antenna was reduced to about 90.5% of that of the conventional one. This antenna with two different novel shapes of DGS was designed and simulated by using the ready-made software package Zeland-IE3D. Finally, it was fabricated by using thin film and photolithographic technique and measured by using vector network analyzer. Good agreements were found between the simulated and measured results.

  8. Nanomaterial building blocks based on spider silk-oligonucleotide conjugates.

    Science.gov (United States)

    Humenik, Martin; Scheibel, Thomas

    2014-02-25

    Self-assembling protein nanofibrils are promising structures for the "bottom-up" fabrication of bionanomaterials. Here, the recombinant protein eADF4(C16), a variant of Araneus diadematus dragline silk ADF4, which self-assembles into nanofibrils, and short oligonucleotides were modified for site-specific azide-alkyne coupling. Corresponding oligonuleotide-eADF4(C16) "click" conjugates were hybridized in linear or branched fashion according to the designed complementarities of the DNA moieties. Self-assembly properties of higher ordered structures of the spider silk-DNA conjugates were dominated by the silk component. Assembled β-sheet rich conjugate fibrils were similar in appearance to fibrils of unmodified eADF4(C16) but enabled the specific attachment of neutravidin-modified gold nanoparticles on their surface directed by complementary biotin-oligonucleotides, providing the basis for functionalization of such conjugates.

  9. Total X-Ray Scattering of Spider Dragline Silk

    Science.gov (United States)

    Benmore, C. J.; Izdebski, T.; Yarger, J. L.

    2012-04-01

    Total x-ray scattering measurements of spider dragline silk fibers from Nephila clavipes, Argiope aurantia, and Latrodectus hesperus all yield similar structure factors, with only small variations between the different species. Wide-angle x-ray scattering from fibers orientated perpendicular to the beam shows a high degree of anisotropy, and differential pair distribution functions obtained by integrating over wedges of the equatorial and meridian planes indicate that, on average, the majority (95%) of the atom-atom correlations do not extend beyond 1 nm. Futhermore, the atom-atom correlations between 1 and 3 nm are not associated with the most intense diffraction peaks at Q=1-2Å-1. Disordered molecular orientations along the fiber axis are consistent with proteins in similar structural arrangements to those in the equatorial plane, which may be associated with the silk’s greater flexibility in this direction.

  10. Two mechanisms for supercontraction in Nephila spider dragline silk.

    Science.gov (United States)

    Guan, Juan; Vollrath, Fritz; Porter, David

    2011-11-14

    Supercontraction in dragline silk of Nephila edulis spider is shown to have two distinct components revealed by single fiber measurements using dynamic mechanical thermal analysis. The first component relies on a contraction of maximum 13% and seems to be associated with relaxation processed through the glass transition, T(g), as is induced by increasing temperature and/or humidity. The second component is induced by liquid water to the total contraction of 30%. The T(g)-induced contraction is linearly correlated with the restraining stress on the fiber, and the mechanical properties of the partially contracted silk have mechanical profiles that differ from both native and fully supercontracted fibers. Here we present novel supercontraction data and discuss their structural origins, examining the relaxation of stretched orientation in the different primary structure sequences.

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

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    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.

  12. Spiders (Araneae of stony debris in North Bohemia

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    Růžička, Vlastimil

    1996-12-01

    Full Text Available The arachnofauna was studied at five stony debris sites in northern Bohemia. In Central Europe, the northern and montane species inhabiting cold places live not only on mountain tops and peat bogs but also on the lower edges of boulder debris, where air streaming through the system of inner compartments gives rise to an exceedingly cold microclimate. At such cold sites, spiders can live either on bare stones (Bathyphantes simillimus, Wubanoides uralensis, or in the rich layers of moss and lichen (Diplocentria bidentata. Kratochviliella bicapitata exhibits a diplostenoecious occurence in stony debris and on the tree bark. Latithorax faustus and Theonoe minutissima display diplostenoecious occurence in stony debris and on peat bogs. The occurence of the species Scotina celans in the Czech Republic was documented for the first time.

  13. The spider family Dysderidae in the Balearic Islands.

    Science.gov (United States)

    Bosmans, Robert; Lissner, Jørgen; Hernández-Corral, Jesús

    2017-10-06

    The spider family Dysderidae in the Balearic Islands counts 6 species, which have all been revised. Dysdera arnedoi Lissner n. sp. and Parachtes riberai Bosmans n. sp. are newly described species from Majorca, where they seem to be confined. A neotype is designated for Dysdera balearica Thorell, 1873 and D. mordax L. Koch, 1882 is considered a junior synonym of the former. Dysdera lata Reuss, 1834 is cited for the first time in Majorca. Dysdera crocata C. L. Koch, 1838 and Harpactea dufouri (Thorell, 1873) occur on all the main Balearic Islands. Harpactea corticalis (Simon, 1882) and H. hombergi (Scopoli, 1763) were misidentified in the past and are deleted from the Balearic Islands list.

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

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    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.

  15. Brown recluse spider (Loxosceles reclusa) envenomation in small animals.

    Science.gov (United States)

    Pace, Lonny B; Vetter, Richard S

    2009-08-01

    To provide a comprehensive review of relevant literature regarding the brown recluse spider (BRS) and to define those criteria that must be satisfied before making a diagnosis of brown recluse envenomation. The complex venom of the BRS contains sphingomyelinase D, which is capable of producing all the clinical signs in the human and some animal models. There is no current commercially available test. In humans there are many proposed guidelines to achieve a definitive diagnosis; however, there are no established guidelines for veterinary patients. Currently, no consensus exists for treatment of BRS envenomation other than supportive care, which includes rest, thorough cleaning of the site, ice, compression, and elevation. Prognosis varies based on severity of clinical signs and response to supportive care. © Veterinary Emergency and Critical Care Society 2009.

  16. 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.

  17. Distribution of the brown recluse spider (Araneae: Sicariidae) in Georgia with comparison to poison center reports of envenomations.

    Science.gov (United States)

    Vetter, Richard S; Hinkle, Nancy C; Ames, Lisa M

    2009-01-01

    Georgia is on the southeastern margin of the native range of the brown recluse spider, Loxosceles reclusa Gertsch and Mulaik. The brown recluse is not a common Georgia spider and has limited distribution in the state. Using recent submissions, previously published records, and examination of museum specimens, we document the spider's presence in 31 (19.5%) of Georgia's 159 counties, with almost all being found in the northern portion. The spider was collected almost exclusively north of the Fall Line (a transition zone separating the Piedmont and the Coastal Plain geological provinces). Only two locations in the southern Coastal Plain province produced L. reclusa specimens; these southern finds are considered spiders that were transported outside their range. There were six finds of the non-native world tramp species, L. rufescens (Dufour), three south of the Fall Line. In conspicuous contrast, over a 5-yr period, a Georgia poison center database recorded 963 reports of brown recluse spider bites from 103 counties. These figures greatly outnumber the historic verifications of brown recluses in the state for both specimen quantity and county occurrence, indicating improbable spider involvement and the overdiagnosis of bites. In the southern half of the state, medical diagnoses of brown recluse spider bites have virtually zero probability of being correct. Bite diagnoses should be made with caution in north Georgia given the spider's spotty distribution with low frequency of occurrence.

  18. PICO, PICOS and SPIDER: a comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews.

    Science.gov (United States)

    Methley, Abigail M; Campbell, Stephen; Chew-Graham, Carolyn; McNally, Rosalind; Cheraghi-Sohi, Sudeh

    2014-11-21

    Qualitative systematic reviews are increasing in popularity in evidence based health care. Difficulties have been reported in conducting literature searches of qualitative research using the PICO search tool. An alternative search tool, entitled SPIDER, was recently developed for more effective searching of qualitative research, but remained untested beyond its development team. In this article we tested the 'SPIDER' search tool in a systematic narrative review of qualitative literature investigating the health care experiences of people with Multiple Sclerosis. Identical search terms were combined into the PICO or SPIDER search tool and compared across Ovid MEDLINE, Ovid EMBASE and EBSCO CINAHL Plus databases. In addition, we added to this method by comparing initial SPIDER and PICO tools to a modified version of PICO with added qualitative search terms (PICOS). Results showed a greater number of hits from the PICO searches, in comparison to the SPIDER searches, with greater sensitivity. SPIDER searches showed greatest specificity for every database. The modified PICO demonstrated equal or higher sensitivity than SPIDER searches, and equal or lower specificity than SPIDER searches. The modified PICO demonstrated lower sensitivity and greater specificity than PICO searches. The recommendations for practice are therefore to use the PICO tool for a fully comprehensive search but the PICOS tool where time and resources are limited. Based on these limited findings the SPIDER tool would not be recommended due to the risk of not identifying relevant papers, but has potential due to its greater specificity.

  19. 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. © 2015 The Authors. Molecular Ecology Resources Published by John Wiley & Sons Ltd.

  20. Weaving the (neuronal) web: fear learning in spider phobia.

    Science.gov (United States)

    Schweckendiek, Jan; Klucken, Tim; Merz, Christian J; Tabbert, Katharina; Walter, Bertram; Ambach, Wolfgang; Vaitl, Dieter; Stark, Rudolf

    2011-01-01

    Theories of specific phobias consider classical conditioning as a central mechanism in the pathogenesis and maintenance of the disorder. Although the neuronal network underlying human fear conditioning is understood in considerable detail, no study to date has examined the neuronal correlates of fear conditioning directly in patients with specific phobias. Using functional magnet resonance imaging (fMRI) we investigated conditioned responses using phobia-relevant and non-phobia-relevant unconditioned stimuli in patients with specific phobias (n=15) and healthy controls (n=14) by means of a differential picture-picture conditioning paradigm: three neutral geometric figures (conditioned stimuli) were followed by either pictures of spiders, highly aversive scenes or household items (unconditioned stimuli), respectively. Enhanced activations within the fear network (medial prefrontal cortex, anterior cingulate cortex, amygdala, insula and thalamus) were observed in response to the phobia-related conditioned stimulus. Further, spider phobic subjects displayed higher amygdala activation in response to the phobia-related conditioned stimulus than to the non-phobia-related conditioned stimulus. Moreover, no differences between patients and healthy controls emerged regarding the non-phobia-related conditioned stimulus. The results imply that learned phobic fear is based on exaggerated responses in structures belonging to the fear network and emphasize the importance of the amygdala in the processing of phobic fear. Further, altered responding of the fear network in patients was only observed in response to the phobia-related conditioned stimulus but not to the non-phobia-related conditioned stimulus indicating no differences in general conditionability between patients with specific phobias and healthy controls. Copyright © 2010 Elsevier Inc. All rights reserved.