Horizontal and vertical distribution of spiders (Araneae) in sunflowers stano Pekár




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Horizontal and vertical distribution of SPIDERS

(Araneae) in sunflowerS

Stano Pekár; Research Institute of Crop Production, Drnovská 507, 161 06 Praha 6 - Ruzyně, Czech Republic. E-mail: pekar@vurv.cz
Abstract. Sunflowers are an increasingly important crop plant in the Czech Republic. The spider fauna of this crop has not been investigated yet. The aim of this study was to monitor the spider fauna of sunflowers and to study the seasonal change in the spatial and vertical distribution of this fauna. For this purpose a small experimental area was used where spiders on each single leave of 50 sunflower plants were visually checked at monthly intervals from spring until autumn. The density of spiders increased during the season reaching a maximum of seven spiders/plant in the autumn shortly before harvest. The spatial distribution changed accordingly, being random in spring and early summer and normal or aggregated toward late summer. Two spider species, Neottiura bimaculata and Theridion impressum (Theridiidae), dominated (96% of all individuals) throughout the season. These two species exhibited a different microhabitat preference: N. bimaculata individuals were found particularly on the lower sunflower leaves, T. impressum preferred higher leaves. The density of the spiders (per leaf) was independent of the density of two dominant pest species, aphids and leafhoppers.

LABORATORY METHODS FOR MAINTAINING AND STUDYING WEB-BUILDING SPIDERS

Samuel Zschokke: Department of Integrative Biology, Section of Conservation Biology (NLU), University of Basel, St. Johanns-Vorstadt 10, CH-4056 Basel, Switzerland. E-mail: samuel.zschokke@alumni.ethz.ch

Marie E. Herberstein: Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia


Abstract. Web-building spiders are an important model system to address questions in a variety of biological fields. They are attractive because of their intriguing biology and because they can be fairly easily collected and maintained in the laboratory. However, the only published instructions for working with web-building spiders are somewhat outdated and not easily accessible. This paper aims to provide an up-to-date guide on how to best collect, keep and study web-building spiders. In particular, it describes how to obtain spiders by capturing them or by raising them from cocoons, how to keep and feed spiders in the laboratory and how to encourage them to build webs. Finally it describes how to document and analyze web building and web structure.
The Life history of Yllenus arenarius (Araneae, Salticidae) – evidence for sympatric populations isolated by the year of maturation
Maciej Bartos: University of Lodz, Department of Teacher Training and Studies of Biological Diversity,Banacha 1/3, 90-237 Lodz, Poland. Email: bartos@biol.uni.lodz.pl
ABSTRACT. The lifespan of Y. arenarius is about 720 days for males and 750 days for females (maximum 770 days), which makes it the longest lived salticid reported from natural conditions. The juvenile spiders emerge at the beginning of June and mature not before the following August. They mate in autumn and hibernate for the second time. For most of the year two cohorts coexist, and at the beginning of June three cohorts can be found simultaneously. The life cycle suggests that in the studied areas there are two groups of individuals, the first of which produces young in odd years, while the other group reproduces in even years. The spider lifespan and phenology suggest no or limited gene flow between the groups.
Spatial association between a spider wasp and its host

in fragmented dune habitats

Dries Bonte1 & Jean-Pierre Maelfait1,2

1Ghent University, Dep. Biology, Research group Terrestrial Ecology, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium. E-Mail: dries.bonte@Ugent.be

2 Institute of Nature Conservation, Kliniekstraat 25, B-1070 Brussels, Belgium
Abstract. In patchily distributed habitats, species potentially occur wherever conditions are suitable or show a restricted distribution, influenced by patch quality, geometry and configuration. If patch isolation appears to be the main determinant of the species’ distribution then dispersal ability is supposed to be limited. Although only scarce literature is available, dispersal limitation seems to be an important factor in determining the spatial population structure in spiders. In this paper, we document on the spatial population structure of the rare wolf spider Alopecosa fabrilis, restricted to fragmented grey dunes along the Flemish coast (Belgium) and ask whether its distribution appears to be affected by aspects of patch configuration. Simultaneously, we investigated whether the local distribution of its main parasitoid, the spider wasp Arachnospila rufa (Hymenoptera, Pompilidae) was associated with its host. Our results indicate that A. fabrilis shows an aggregative population structure, which is determined by the distance to nearest occupied patch, indicating that spatially correlated habitat quality probably determine its occurrence. Although spider wasps are generally characterized as non-specialists, the almost complete covariation between its spatial occurrence and that of A. fabrilis, indicates that spider hunting wasps may, at least temporally and locally, show a restricted host-range. As a result, the presence of a rather generalist parasitoid is a good predictor for the presence of nocturnal and burrowing dune wolf spider.
EARLY SUCCESSION OF A BOREAL SPIDER COMMUNITY AFTER FOREST FIRE

Seppo Koponen: Zoological Museum, University of Turku, FI-20014 Turku, Finland. E-mail: sepkopo@utu.fi
ABSTRACT. Ground-living spiders were studied, using pitfall traps, 3--4 months after a wildfire, and then during three post-fire summers. The study area was a pine (Pinus sylvestris) forest in southwestern Finland. Lycosidae dominated in individual numbers at the burned site and Linyphiidae at the control. In species numbers, Linyphiidae dominated at both sites, and Lycosidae, Gnaphosidae and Theridiidae were more species-rich at the burned than control site. The lycosid Xerolycosa nemoralis was dominant at the burned site, and the linyphiid Agyneta cauta at the control. Abundant species found only at the burned site included Xerolycosa nemoralis, Pardosa riparia, Acantholycosa lignaria and Micaria silesiaca. Tapinocyba pallens and Pardosa lugubris occurred at both sites in large numbers. A slight positive effect of fire on the species richness was found. Species with more or less stable abundance at the burned site during the study period included Pardosa riparia, P. lugubris and Diplostyla concolor. Increasing abundance in successive years occurred for Acantholycosa lignaria, Micaria silesiaca, Xerolycosa nemoralis and for the family Lycosidae. Euryopis flavomaculata, Agyneta rurestris, Tapinocyba pallens and the family Linyphiidae showed a decreasing abundance during the study years. The spider community at the burned site remained clearly different compared to the control during three post-fire summers, primarily caused by the abundance of Gnaphosidae and Lycosidae.
Are salt marsh invasions by the grass Elymus athericus a threat for two dominant halophilic wolf spiders?

Julien Pétillon1,2, Frédéric Ysnel1, Jean-Claude Lefeuvre3 and Alain Canard1

1 E.R.T. "Biodiversité fonctionnelle et Gestion des territoires ", Université de Rennes 1, 263 Av. du Général Leclerc, CS 74205, 35042 Rennes Cedex, France. E-mail: julien.petillon@univ-rennes1.fr

2 U.M.R. C.N.R.S. " Fonctionnement des Ecosystèmes et Biologie de la Conservation", Université de Rennes 1, 263 Av. du Général Leclerc, CS 74205, 35042 Rennes Cedex, France

3 Laboratoire d'Évolution des Systèmes Naturels et Modifiés, Muséum National d'Histoire Naturelle, 36 rue Geoffroy Saint Hilaire 75005 Paris, France
Abstract. As a result of the Elymus athericus (Poaceae) invasion in the last ten years, a major change in vegetation cover has occurred in salt marshes of the Mont Saint-Michel bay (France). In this study, we investigated if the high conservation value of invaded salt marshes is preserved. Abundances, densities and flood resistance abilities of the dominant halophilic species Arctosa fulvolineata (nocturnal lycosid) and Pardosa purbeckensis (diurnal lycosid) were compared in both natural and invaded habitats. Elymus invasion involved both positive and negative aspects with respect to the conservation value of the salt marshes invaded: the P. purbeckensis population was clearly reduced in invaded habitats, whereas A. fulvolineata seemed to derive high benefits from the invasion. We supposed that abiotic parameters of the new habitat (mainly vegetation and litter characteristics) affected the two species differently with respect to their aut-ecology and their flood resistance abilities. Furthermore, food resources (estimated by different macrofauna density measurements) were likely to be reduced for P. purbeckensis in invaded habitats and unchanged for A. fulvolineata. Lastly, we hypothesize that individuals of P. purbeckensis are subject to increased interspecific competition (measured as intra-guild densities), whereas spiders from the same guild as A. fulvolineata have not increased in invaded habitats, resulting in an unchanged competition level.
The Diet of the Cave Spider Meta menardi (Latreille 1804) (araneae, Tetragnathidae)

Peter Smithers: School of Biological Sciences, University of Plymouth. Drake Circus, Plymouth, Devon, PL4 8AA, UK. E-mail: Psmithers@plymouth.ac.uk

ABSTRACT. This study investigated the range and number of prey consumed by a population of M. menardi in an abandoned mine drainage adit at Mary Tavy, on the edge of Dartmoor (Devon, UK). The adit was visited each week from October1997 to November 1998 and any spider found feeding was interrupted and its prey removed and preserved in alcohol. Over the 13 months a total of 69 prey were recovered representing 18 taxa. While a number of flying insects used the adit as a refuge in which to over winter they formed a small percentage of the total prey consumed. Most of the prey were members of the soil or litter fauna (myriapods and slugs) that were observed walking over the surface of the adit walls.
THE spider FAUNA OF THE irrigated rice ecosystem

in central Kerala, INDIA ACROSS different elevational ranges

P.A. Sebastian: Division of Arachnology, Dept. of Zoology, Sacred Heart College, Thevara, Cochin-682 013, Kerala, India. E-mail: drpothalil@rediffmail.com

M.J. Mathew: Division of Arachnology, Dept. of Zoology, Sacred Heart College, Thevara, Cochin-682 013, Kerala, India.

S. Pathummal Beevi: Dept. of Agricultural Entomology, Biological Control of Crop Pests & Weeds, College of Horticulture, Kerala Agricultural University, Vellanikkara-680 654, Thrissur, Kerala, India.

John Joseph: Division of Arachnology, Dept. of Zoology, Sacred Heart College, Thevara, Cochin-682 013, Kerala, India

C.R. Biju: Dept. of Agricultural Entomology, Biological Control of Crop Pests & Weeds, College of Horticulture, Kerala Agricultural University, Vellanikkara-680 654, Thrissur, Kerala, India.
Abstract. A survey of spiders associated with the irrigated rice ecosystem in central Kerala, India was conducted across different elevational ranges. Spiders were collected from rice fields of high ranges, midland and low land areas in two cropping seasons viz., June--September 2002 (Kanni Krishy) and October 2002--February 2003 (Makara Krishy) with a total of 144 hours of sampling time distributed across the two seasons. The sampling areas constituted Adimali and Marayoor of Idukki district (high range), Vannappuram of Idukki district and Kothamangalam of Ernakulam district (midland) and Parakkadavu and Piravom of Ernakulam district (lowland). Visual searching methods were used to sample the spider fauna from quadrats. A total of 1130 individuals belonging to 92 species, 47 genera and 16 families were recorded during the study period. Araneidae and Tetragnathidae were the dominant families and Tetragnatha mandibulata Walckenaer 1842 (Family Tetragnathidae) the most abundant species. Various diversity indices, as well as richness and Chao I estimator were used to analyze the possible effect of elevation on species occurrence; the results showed that species richness and diversity were the highest in Parakkadavu, which is a lowland area. In a cluster analysis the localities belonging to the same elevation were found to form separate groups. The species fell into seven feeding guilds. Orb weavers were dominant at all study sites.
Ecological profiles of harvestmen (Arachnida, Opiliones) from Vitosha Mountain (Bulgaria): A mixed modelling approach using GAMs

Plamen G. Mitov: Department of Zoology and Anthropology Faculty of Biology, University of Sofia, 8 Dragan Tsankov Blvd., 1164-Sofia, Bulgaria. E-mail: pl_mitov@yahoo.com

Ivailo L. Stoyanov: Biodiversity Department, Central Laboratory of General Ecology, 2 Yurii Gagarin Street, 1113-Sofia, Bulgaria
ABSTRACT. The present study is based on a large-scale sampling program carried out in the area of Vitosha Mountain (Bulgaria). The ecological profiles of the Opiliones inhabiting the investigated area are modelled by a mixed approach, using Generalized Additive Models (GAMs) over a Multiple Correspondence Analysis (MCA, performed on the sites by environmental variables matrix) ordination plot. According to the literature data describing the harvestmen species from Vitosha Mountain, the most important factor determining the ecological classification of the Opiliones is the habitat type. The modelled ecological profiles revealed that the elevation contributes the most to the ecological characterization of the Vitosha harvestmen species, followed by the habitat type and moisture regime of the sampling localities. Few harvestmen species demonstrate preferences to the middle- and high-mountain zones, while the majority of harvestmen species are confined exclusively to the low-mountain zone. The different species showed different responses (most of them were linear, not unimodal) towards the environmental variables.
INFLUENCE OF GRAZING BY LARGE MAMMALS ON THE SPIDER COMMUNITY OF A KENYAN SAVANNA BIOME

Charles M. Warui1, 2, Martin H. Villet2, Truman P. Young3 & Rudy Jocqué4

1 Department of Invertebrate Zoology, National Museums of Kenya, P.O. Box 40658-00100 GPO, Nairobi, Kenya, cmwarui@yahoo.com

2 Department of Zoology and Entomology, Rhodes University, 6140 Grahamstown, South Africa

3 Department of Plant Sciences, University of California, Davis, 95616 USA.

4 Invertebrate Section, Department of African Zoology, Royal Museum for Central Africa, Leuvensesteenweg 13, B-3080 Tervuren, Belgium
Abstract. Pitfall trap and sweep net samples were taken over a period of fifteen months (2002--2003) in the Kenya Long-term Exclosure Experiment (KLEE), in which the presence of domestic and wild herbivores have been independently manipulated since 1995. ANOVA and ANCOVA showed that the exclosure treatments significantly affected plant cover, with the presence of cattle significantly reducing the relative vegetation cover and spider diversity. Herbivory by indigenous mega- and meso-herbivores did not have a significant influence on the diversity of the spider fauna, but abundance of three dominant species (Cyclosa insulana Costa (Araneidae), Argiope trifasciata Forskål (Araneidae) and Runcinia flavida Simon (Thomisidae)) decreased in cattle-grazed plots. In contrast, Aelurillus sp. became more prevalent where cattle have been grazing. Multivariate analyses revealed that the spider community responded to grazing pressure by aggregating into three groups that reflected control, cattle grazing and non-cattle grazing clusters. It was probable that the direct effects on vegetation mediated an indirect influence of herbivores on spider diversity. The relative vegetation cover was a positive predictor of spider diversity. Spider communities were found to be an indicator of the activity of mammals and could be used as indicators of land use changes and for bio-monitoring.
SPIDER (ARANEAE) COMMUNITIES OF SCREE SLOPES IN THE CZECH REPUBLIC

Vlastimil Růžička: Institute of Entomology, Czech Academy of Sciences, Branišovská 31, CZ-370 05 České Budějovice, Czech Republic

Leoš Klimeš: Institute of Botany, Czech Academy of Sciences, Dukelská 135, CZ-379 01 Třeboň, Czech Republic
ABSTRACT. We assessed the effects of environmental factors on spider communities in screes (sloping mass of coarse rock fragments) of the Czech Republic, based on catches from 325 pitfall traps, exposed for 177--670 days, from 1984--2000. Bootstrap resampling was applied to test for fuzziness of the partitions in cluster analysis of the samples. Two distinct spider communities were identified. The first one was confined to sites where ice is formed and persists until late summer or over the whole year. This community consists of numerous relict spiders, such as Bathyphantes simillimus buchari Růžička 1988, Diplocentria bidentata (Emerton 1882) and Lepthyphantes tripartitus Miller & Svatoň 1978, possibly persisting in these cold screes from the early postglacial period. The other community included all other sites, irrespective of their environmental characteristics. Monte Carlo simulations were used to test the significance of environmental factors and their interactions on the studied communities. Ice formation near the traps and position of the traps within individual screes were the most significant factors, followed by the depth of the traps within the scree, diameter of stones forming the scree, and altitude. A marginally significant effect was found for organic content in the scree matter, whereas presence of trees and phytogeographical districts appeared non-significant. Our analyses support the view that spiders inhabiting cold screes in Central Europe belong to a unique relict community of species requiring cold and stable microclimate.
FAUNISTIC SIMILARITY AND HISTORIC BIOGEOGRAPHY

OF THE HARVESTMEN OF SOUTHERN AND SOUTHEASTERN

ATLANTIC RAIN FOREST OF BRAZIL

Ricardo Pinto-da-Rocha and Márcio Bernardino da Silva: Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11461, 05422-970, São Paulo, SP, Brazil. Email: ricrocha@usp.br

Cibele Bragagnolo: Museu de Zoologia, Universidade de São Paulo
ABSTRACT. Harvestmen show a high degree of endemism in the Atlantic Rain Forest (eastern coast of Brazil). This biome shows the highest diversity of harvestmen inhabiting Brazil; 2/3 of the species are found in this area. Most of the species are distributed in a few thousand square kilometers, almost always within one mountain range. The similarities of 26 localities were studied, including sites from the Brazilian savanna, using data from recent collections (more than 8,000 specimens) and published data. A cluster analysis using Sørensen´s Coefficient indicated a high degree of endemism of species of harvestmen (similarity indexes below 0.5). It resulted in six main clusters related to the large mountain ranges and near sites. A high variation in richness was observed; 4--64 species per locality. The distribution of 84 species of four recently reviewed subfamilies of Gonyleptidae (Goniosomatinae, Caelopyginae, Progonyleptoidellinae and Sodreaninae) was studied. Eleven areas of endemism, with 3--14 endemic species each, were proposed. A primary Brooks Parsimony Analysis showed a possible first vicariant event splitting the fauna of two northern areas from the rest, and a second event splitting the fauna of southern areas (until 24º35"S) from those areas related to certain mountain ranges in the central Atlantic Rain Forest. The vicariant events were related to the uplifting of the Serra do Mar and the Serra da Mantiqueira, and the appearance of large rivers and climatic changes.
A SURVEY OF SPIDERS (ARANEAE) WITH HOLARCTIC DISTRIBUTION

Yuri M. Marusik: Institute for Biological Problems of the North, RAS, Portovaya Str. 18, Magadan 685000, Russia. E-mail: yurmar@mail.ru

Seppo Koponen: Zoological Museum, University of Turku, FI-20014 Turku, Finland.
ABSTRACT. Of the 13,800 species distributed in the Holarctic Region only 395 are known both from Eurasia and North America. Of these only 105 species are distributed throughout the whole Holarctic (circum-Holarctic species). In addition, 28 species have an almost complete Holarctic distribution, occurring from Europe to northwestern North America (subcircum-Holarctic species). Species with a circum-Holarctic distribution were found in 13 families. The highest numbers of circum-Holarctic species were in the families Linyphiidae (37), Theridiidae (14), Araneidae (13) and Gnaphosidae (11). The percentage of the circum-Holarctic species among the Holarctic spiders is highest in Philodromidae (2.4%), Araneidae (2.2%), Theridiidae (2.0%) and Tetragnathidae (1.9%). These families encompass mainly herb-bush-tree dwellers. Somewhat unexpectedly it was found that most circum-Holarctic species occupy the boreo-nemoral zone (41%), or may even have a polyzonal range (23%). Twenty-nine species (28%) of the circum-Holarctic spiders have a northern distribution; most of them occurring both in arctic and boreal zones.
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