99 research outputs found

    Tests for attraction to prey and predator avoidance by chemical cues in spiders of the beech forest floor

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    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

    The spider fauna of the epigeic and the shrub stratum of a thermophilic wood edge in Bavaria (Germany)

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    Faunistische Untersuchungen an Spinnen wurden in den letzten Jahrzehnten überwiegend mit Barberfallen durchgeführt, da die Probennahme gut standardisierbar ist und vor allem unabhängig von der Witterung erfolgen kann. Die Kenntnisse über die Spinnenbesiedlung höherer Straten sind nach wie vor lückenhaft. Systematische Untersuchungen an Gebüschen mit Hilfe des Klopfschirms liegen nur von HARTMANN (1984) aus Oberfranken und von NAHRlG (1987) aus dem Kraichgau vor. In der vorliegenden Untersuchung wurde ein thermophiles Waldmantelgebüsch in Mittelfranken regelmassig beklopft. Um die Besiedlung unterschiedlicher Straten vergleichen zu können, wurde zusätzlich die epigäische Spinnenfauna des Waldmantels mit Barberfallen erfasst

    Behavioral, Histological, and Physiological Evaluation of the Effect of Imidacloprid on the Spider Misumenops maculissparsus

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    The aim of this study was to evaluate the effects of the neonicotinoid insecticide imidacloprid (commercial formulation) on juveniles of the spider Misumenops maculissparsus (Keyserling, 1891). We first analyzed whether spiders recognized the presence of the insecticide on surfaces and in drinking water (in the form of droplets). Afterwards, we investigated if the insecticide generated histologic, physiologic and/or biochemical alterations. We observed that spiders do not detect the insecticide on a surface (e. g., paper) or in the form of droplets. After the imidacloprid ingestion by droplet intake, most spiders exhibited a paralysis that reverted after 48 h. Consequently, we observed histopathologic damage (i. e., pigment accumulation, necrosis, and cuticle detachment), and an increased catalase activity and total-protein concentration in the individuals treated. The activities of glutathione-S-transferase, glutathione peroxidase, glutathione reductase, and superoxide dismutase, however, did not undergo significant variations. The results obtained emphasize the need to consider different classes of biomarkers like catalase and other proteins to identify and evaluate the histologic, biologic, and biochemical effects of imidacloprid, one of the most widely used insecticides.Fil: Gabellone, Cecilia SofĂ­a. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Centro de Estudios ParasitolĂłgicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios ParasitolĂłgicos y de Vectores; ArgentinaFil: Molina, Gabriel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Arrighetti, Florencia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Laino, Aldana. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Garcia, Carlos Fernando. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentin

    Supplement to "Katalog der schweizerischen Spinnen" - 2. new records from 1993 to 1999

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    Since the first supplement in 1993 38 species are recorded as new to Switzerland. 14 species are recorded here for the first time for Switzerland: Enoplognatha oelandica (THORELL, 1875); Theridion hemerobium SIMON, 1914; Diplocephalus crassilobus (SIMON, 1884); Diplocephalus pavesii PESARINI, 1996; Linyphia tenuipalpis SIMON, 1884; Porrhomma cambridgei MERRETT, 1994; Porrhomma rosenhaueri (L.KOCH, 1872); Pachygnatha terilis THALER,1991; Hahnia candida SIMON, 1975; Cryptodrassus hungaricus (BALOGH, 1935); Zelotes devotus GRIMM, 1982; Zelotes hermani (CHYZER,1897); Zelotes tenuis (L.KOCH, 1866); Tmarus stellio SIMON, 1875.24 species were published in other papers and are listed here only to complete the catalogue: Episinus maculipesCAVANNA, 1876; Robertus kuehnae BAUCHHENSS & UHLENHAUT, 1993; Centromerus capucinus (SIMON, 1884); Diplocephalus dentatusTULLGREN, 1955; Lepthyphantes arenicola DENIS, 1964; Lepthyphantes insignis (O.P.-CAMBRIDGE, 1913); Lessertia dentichelis (SIMON, 1884); Maro lepidus CASEMIR, 1961; Prinerigone vagans (AUDOUIN, 1826); Pseudomaro aenigmaticus DENIS, 1966; Silometopus bonessi CASEMIR, 1970; Acantholycosa norvegica (THORELL, 1872); Acantholycosa rupicola (DU FOUR, 1820); Pardosa alacris (C. L. KOCH, 1933); Pardosa baehrorum KRONESTEDT, 1999; Pardosa saltans TOPFER-HOFMANN im Druck;Altella biuncata(MILLER, 1949); Agroecainopina O. P.-CAMBRIDGE, 1886; Clubiona pseudoneglecta WUNDERLlCH, 1994; Zodarion italicum (CANESTRINI, 1868);Synaphosus sauvageOVTSHARENKO, LEVY & PLA TNICK, 1994;Zora parallela SIMON, 1878; Thanatus atratus SIMON, 1875; Ozyptila pul/ata (THORELL, 1875).4 species have to be deleted from the catalogue: Diplocephalus foraminifer (O.P.-CAMBRIDGE, 1875); Diplocephalus aft. procer (SIMON, 1884) sensu THALER (1972); Acantholycosa pyrenaea (SIMON, 1876); Zodarion gal/icum (SI MON, 1873). The actual number of known species in Switzerland is 926

    Spiders (Arachnida, Araneae) in winter : differences in the appearance of species in small-scale spaces as a response to daily temperature fluctuations

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    Pitfall traps were positioned for the investigation of the spider fauna at the northern and southern slopes of three mountain ridges (Chilchberg, Riedberg, and Buechenberg, municipalities Nunningen and Zullwil, canton Solothurn, Switzerland) within the Swiss Jura Mountains. The temperature in the upper litter was measured at three hour intervals. Independent of the weather more or less clear differences between northern and southern slopes could be observed. Maximum day temperature fluctuations of 15.8 °C were measured. There were no significant differences in spider communities based on quantitative comparison methods. However, a qualitative analysis showed major differences in species composition. More than 50% of all species per investigation area showed clear preferences for the northern or the southern slope, with more then two thirds of the individuals only found on either the north or south slopes

    Can urban consolidation limit local biodiversity erosion? Responses from carabid beetle and spider assemblages in Western France

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    International audienceDuring the last decades, urban consolidation has been developed to minimize spatial expansion of cities, yet very few studies investigated whether it would actually reduce some negative effects of urbanization on biodiversity. In this study, we compared the invertebrate assemblages associated with two distinct urban forms (compact vs. conventional), focusing on two arthropod taxa often used as bioindicators, and dominant in urban habitats: spiders and carabid beetles. The following parameters were estimated: assemblage composition, species richness, activity-density total, per species (excluding seldom-recorded species) and per size class. The field collection was performed in 2009 using pitfall traps randomly set in hedgerows within 6 sites (representing 251 traps). A total of 4,413 spiders belonging to 117 species and 2,077 adult carabid beetles belonging to 39 species were collected. We found few significant differences in carabid beetle and spider assemblages between the two urban forms. The species richness of both groups was independent from the neighborhood design. Only four species of carabid beetles and ten of spiders significantly reacted to the neighborhood design, and no difference was found among the two designs for all other species. Large carabid beetles were more abundant and small spiders less abundant in the new neighborhood design compared to the conventional one. For both carabid beetles and spiders, no difference in assemblage composition was found between neighborhood designs. We therefore conclude that urban consolidation, by permitting a higher human density with similar arthropod assemblages, could contribute to reduce biodiversity loss in cities

    Der Einfluss von Habitatparametern auf die epigäische Arthropodengemeinschaft in repräsentativen Bestandstypen mittelschwäbischer Wirtschaftswälder

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    Da Arthropoden über 75% der rezenten Artenvielfalt stellen (WILSON 1992) und auch in mitteleuropäischen Wäldern mit hohen Arten- und Individuenzahlen vertreten sind (HÄNGGI et al. 1995, STIPPICH 1986, ZIESCHE & ROTH 2004), kommt diesem Taxon hinsichtlich der Lebensraumfunktion von Wäldern eine wichtige Bedeutung zu. Darüber hinaus weisen viele dieser Zoophagen enge Korrelationen zur Ausprägung (a)biotischer Habitatparameter auf (LOREAU 1986, PLATEN 1992). Welche Umweltparameter (z.B. Baumartenspektrum, Kronenschlussgrad, Diversität und Deckungsgrad der Bodenvegetation) das Vorkommen von Arten in mitteleuropäischen Wäldern steuern, ist bisher nur unzureichend geklärt (NIEMELÄ et al. 1996). Ziel der Untersuchungen war es, die Lebensraumfunktion repräsentativer Typen von Wirtschaftswäldern der Region Mittelschwaben am Beispiel der Araneae und Carabidae zu analysieren und wichtige Faktoren für das Vorkommen von Arten und Artengruppen zu ermitteln. Dabei standen folgende Fragen im Mittelpunkt: 1. Welchen Einfluß hat die überschirmende Baumart auf die Artenmuster der epigäischen Raubarthropodengemeinschaften? 2. Welche Hauptumweltfaktoren sind im Jahresverlauf für die Bildung von Artengemeinschaften verantwortlich sind?The study focused on the habitat function of different forest types (pure spruce and douglas fir stands, mixed forests with spruce and beech as well as beech and oak) on soil dwelling zoophagous arthropods (Carabidae, Araneae) in Bavaria. Our aim was to examine the effects of microspatial heterogeneity on the species patterns of predacious arthropods and to assess the most important environmental parameters which determine the occurrence of species by applying statistical methods. Arthropods were sampled by pitfall traps (n = 8 per investigation area) during the vegetation period of 2002. We found a very sensitive segregation of species assemblages along environmental gradients on an extremely small spatial scale. Species distribution varied within few meters and changed seasonally. The degree of canopy closure was an important factor determining the patterns of spider and ground beetle distribution, because it affects the microclimatic conditions on the forest floor and thus the performance of the ground vegetation. Another important factor for the spatial distribution of predacious arthropods in forests was the kind and structure of the litter layer

    Spiders from ecological compensation areas in the Swiss cantons Aargau and Schaffhausen (Arachnida: Araneae) – with remarks on Phrurolithus nigrinus (Corinnidae)

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    The spider fauna of open habitats adjacent to arable land was investigated in northern Switzerland. The three habitat types were (1) herbaceous edges of fields (Sa), (2) fallow land sowed with flowers (BB), and (3) grass borders of fields (GS). Four funnel pitfall traps (10 cm diameter) were used to catch spiders in three stripe-types in two geographical regions in two years over 5 weeks in May and June: in total 12 sets of data. Spider species typical for open habitats were dominant, mostly lycosids (6 of the 10 most active species). The results were analysed together with environmental factors using a canonical correspondence analysis (CCA) and spiders were compared with carabid beetles (Coeloptera: Carabidae). Geographical region, though not very distant, had the largest influence on both spiders and carabids. The age and type of the habitats had a stronger influence on spiders than on carabids. In spiders a larger part of the total variance was explained by the analysed factors. Finally we discuss briefly a remarkable spider species. A review of all known records of Phrurolithus nigrinus in Switzerland and Germany, together with adjacent regions in France, is given. Its phenology is indicated, its habitat discussed and the overall distribution within Europe is listed
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