Abstracts to Articles

The Journal of Arachnology

Volume 33 Number 2

Horizontal and vertical distribution of spiders (Araneae) in sunflowers

by Stano Pekár;  Research Institute of Crop Production, Drnovská 507, 161 06 Praha 6 - Ruzyne, 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


LABORATORY METHODS FOR MAINTAINING AND STUDYING WEB-BUILDING SPIDERS

by 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 However, the only published instructions for working with web-building spiders are somewhat outdated and not easily accessible.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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


The Life history of Yllenus arenarius (Araneae, Salticidae) - evidence for sympatric populations isolated by the year of maturation

by 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Spatial association between a spider wasp and its host in fragmented dune habitats

by Dries Bonte (1) & Jean-Pierre Maelfait (1,2)

(1) Ghent 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


EARLY SUCCESSION OF A BOREAL SPIDER COMMUNITY AFTER FOREST FIRE

by 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Are salt marsh invasions by the grass Elymus athericus a threat for two dominant halophilic wolf spiders?

by Julien Pétillon ( 1,2), Frédéric Ysnel (1), Jean-Claude Lefeuvre (3) and Alain Canard (1)

(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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


The Diet of the Cave Spider Meta menardi (Latreille 1804) (Araneae, Tetragnathidae)

by 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


The spider fauna of the irrigated rice ecosystemin central Kerala, India across different elevational ranges

by 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Ecological profiles of harvestmen (Arachnida, Opiliones) from Vitosha Mountain (Bulgaria): A mixed modelling approach using GAMs

by 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

ABSTRACTThe 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


INFLUENCE OF GRAZING BY LARGE MAMMALS ON THE SPIDER COMMUNITY OF A KENYAN SAVANNA BIOME

by Charles M. Warui (1, 2), Martin H. Villet (2), Truman P. Young (3) & Rudy Jocqué (4)

(1) Department of Invertebrate Zoology, National Museums of Kenya, P.O. Box 40658-00100 GPO, Nairobi, Kenya
E -mail: 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


SPIDER (ARANEAE) COMMUNITIES OF SCREE SLOPES IN THE CZECH REPUBLIC

by Vlastimil Ruzicka  Institute of Entomology, Czech Academy of Sciences, Branisovská 31, CZ-370 05 &Ceské Budejovice, Czech Republic

Leos Klimes:  Institute of Botany, Czech Academy of Sciences, Dukelská 135, CZ-379 01 Trebon, Czech Republic

ABSTRACTWe 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 Ruzicka 1988, Diplocentria bidentata (Emerton 1882) and Lepthyphantes tripartitus Miller & Svaton 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


FAUNISTIC SIMILARITY AND HISTORIC BIOGEOGRAPHY OF THE HARVESTMEN OF SOUTHERN AND SOUTHEASTERNATLANTIC RAIN FOREST OF BRAZIL

by 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


A SURVEY OF SPIDERS (ARANEAE) WITH HOLARCTIC DISTRIBUTION

by 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.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Fauna and Zoogeography of Spiders (Araneae) in Bulgaria

by Christo Deltshev:  Institute of Zoology, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Bld., 1000 Sofia, Bulgaria.
E-mail:cdeltshev@zoology.bas.bg

ABSTRACT.  Bulgaria is home to 975 species of spiders in 41 families. This number was established after a critical review of the existing literature and taxonomic review of the available collections. The spiders are distributed in all districts of Bulgaria, occurring in lowlands, forests, mountains, caves and urban territories. According to their current distribution the established 975 species can be split into 27 zoogeographical categories, grouped into five major chorotypes (Cosmopolitan, Holarctic, European, Mediterranean, Endemics). The largest number of species belongs to the widely distributed species in the Holarctic, but the most characteristic are the endemics. Their established number (76 species) is high and reflects the local character of the fauna. This phenomenon can be attributed to the relative isolation of the mountains compared with the lowlands in the context of paleo-enviromental changes since the Pliocene.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Geographical context of Speciation in a radiation of Hawaiian Tetragnatha Spiders (ARANEAE, TETRAGNATHIDAE)

by Rosemary G. Gillespie:  Division of Insect Biology, University of California Berkeley, 137 Mulford Hall, Berkeley, California 94720-3114, U.S.A.

ABSTRACT. Adaptive radiation involves the diversification of species each adapted to exploit different ecological roles. I have studied a radiation of spiders in the genus Tetragnatha (Tetragnathidae) in the Hawaiian Islands to elucidate processes involved in such diversification. The temporal framework of the Hawaiian Islands allows examination of the changing pattern of adaptive radiation over time, as lineages have generally progressed down the island chain from older to younger islands. Species of Tetragnatha in the spiny-leg clade on any one island are typically most closely related to others on the same island, and the same set of ecological forms (ecomorphs) has evolved repeatedly on different islands. These results indicate that adaptive radiation frequently involves ecological divergence between sister taxa to allow multiple close relatives to co-occur in the same habitat. The current study examines the geographical context within which these species arose. I focus on a clade of 5 species that occur on the volcano of East Maui; at any given site 3 species can co-occur, one of each of  3 different ecomorphs. Mitochondrial DNA sequences from populations of these 5 species from throughout their distribution (Maui, Lanai and Molokai) were used to infer the geographic history of the species on East Maui and to determine whether diversification likely occurred in situ, or alternatively whether diversification occurred in allopatry on different volcanoes. Although ecological differentiation between taxa is evident, allopatry is clearly implicated in the initial divergence of taxa. Further study is required to understand the nature of the interplay between allopatry and ecological divergence in species formation.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Diversity of arboreal spiders in primary and disturbed tropical forests

by Andreas Floren:  Dept. of Animal Ecology and Tropical Biology, University Wuerzburg, Biozentrum Am Hubland, D-97074 Wuerzburg, Germany.
E-mail: floren@biozentrum.uni-wuerzburg.de

Christa Deeleman-Reinhold:  Sparrenlaan 8, 4641 GA Ossendrecht, The Netherlands

ABSTRACT.  This study investigates how arboreal spider communities in SE-Asian primary lowland rain forests change after anthropogenic disturbance. Two types of secondary forests were distinguished: 1) forests adjacent to each other, which finally merged into primary forest and 2) forests that were isolated by at least 10 km from the primary forest. Three forests of different age were investigated from each type and compared with undisturbed primary forest. All disturbed forests had been used some years for agriculture and were then left between 5 and 50 years to regenerate naturally. Spiders from at least seven trees per forest type were collected using insecticidal knockdown fogging and sorted to species or morphospecies level. Spiders represented between 5--10% of all canopy arthropods. A similar number of spiders were collected per square meter from all trees. However, communities in the primary forest differed greatly in their alpha- and beta-diversity and in community structure from those in the disturbed forest types. Diversity was high in the regenerating forests connected to the primary forest and approximated the conditions of the primary forest during the course of forest succession. In contrast, the isolated forests were of low diversity and communities showed little change during forest regeneration. These results indicate the importance of a species-source from which disturbed forests can be recolonized. However, even under optimal conditions this process needed decades before spider communities became similar to those of the primary forest. With no species-source available, spider diversity changed little during 50 years of forest regeneration. In the isolated forest we observed a drastic turnover from forest species towards species characteristic of open vegetation and shrubs. Our results give an indication of how large a loss in diversity can be expected in isolated forest fragments.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


 

GENDER SPECIFIC DIFFERENCES IN ACTIVITY AND HOME RANGE REFLECT MORPHOLOGICAL DIMORPHISM IN WOLF SPIDERS (ARANEAE, LYCOSIDAE)

by Volker W. Framenau1:  Department of Zoology, The University of Melbourne, Parkville, Victoria, 3010, Australia.
E-mail: volker.framenau@museum.wa.gov.au

ABSTRACT.  Sexual dimorphism of locomotory organs appears to be common in a variety of arthropods, however, the underlying evolutionary mechanisms remain poorly understood and may be the consequence of natural or sexual selection, or a combination of both. I analyzed the activity pattern of seven cohorts of a wolf spider, Venatrix lapidosa, over four consecutive years. Males appear to be the more active sex in search for a mate as they show temporarily higher activity prior to the periods of female brood care. Morphometric data on leg length showed comparatively longer legs for males than females. Allometric leg elongation in all four legs of males arises only after the final molt suggesting its significance in reproductive behavior such as mate search. A comparative analysis of two Australasian wolf spider genera with different activity profile of females, Venatrix (sedentary females) and Artoria (vagrant females) provides further evidence that limb elongation in males mainly arises due to indirect male mate competition.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


EVOLUTION OF ORNAMENTATION AND COURTSHIP BEHAVIOR IN SCHIZOCOSA: INSIGHTS FROM A PHYLOGENY BASED ON MORPHOLOGY (ARANEAE, LYCOSIDAE)

by Gail E. Stratton:  Department of Biology, University of Mississippi, University, Mississippi 38677, U.S.A.
E-mail: Byges@olemiss.edu

ABSTRACTA phylogenetic analysis for the North American Schizocosa species was undertaken by scoring 49 morphological characters for 31 taxa representing all of the Nearctic species of Schizocosa plus individuals that are hybrids between S. ocreata and S. rovneri. Rabidosa rabida, Allocosa georgicola and Gladicosa pulchra were used as outgroups. Three clades are recognized: a large clade from eastern North America (Clade A) within which is nested the S. ocreata clade; Clade B, which includes the widespread S. avida and the western S. mccooki, and a smaller, third clade, Clade C. Sexual ornamentation occurs on the first legs of mature males of several species within the Schizocosa and takes the form of pigmentation and or bristles primarily on the tibia of leg I; there is at least one species with bristles in each of the three main clades. Mapping the occurrence of male ornamentation on the preferred phylogeny suggests that ornamentation evolved 5 or 6 separate times and was subsequently lost 2 or 3 times. The ornamentation is concentrated in the S. ocreata clade, a clade defined by a finger like projection on the paleal process of the male pedipalp. Courtship behavior is known for 20 of the 31 taxa. All species studied utilize chemical communication and seismic signals for communication; some species also have distinct visual signals. Seismic signals are produced by palpal drumming (as is seen in several species within Clade B), or by stridulation (seen in Clade A). Visual signals consisting of movements of the first pair of legs are common in species that are distinctly ornamented. This study provides the first phylogenetic study of a North American genus of wolf spider and provides morphometric comparisons of the North American species in Schizocosa

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Factors affecting cannibalism among newly hatched wolf spiders (Lycosidae, Pardosa amentata)

by Aino Hvam(1), David Mayntz (1, 2, 3) and Rikke Kruse Nielsen (1)

(1) Department of Ecology and Genetics, University of Aarhus, Bldg. 540, DK-8000 Århus C, Denmark.
(2) Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
(3) Corresponding author.

ABSTRACTCannibalism is a common phenomenon among young wolf spiders (Lycosidae). The purpose of this study was to investigate how various factors influence cannibalistic tendencies in hatchlings of Pardosa amentata (Clerk 1757). The basic experimental approach was to place pairs of unfed hatchlings of similar body mass in small containers without prey and to measure if and when cannibalism happened. From the data, we identified three different cannibalistic strategies. One large group of hatchlings never cannibalized and thus died from starvation. Another group cannibalized shortly before the time at which they were predicted to die from starvation. In these spiders, there was a strong positive relationship between average body mass of the contestants and their latency to cannibalize. A third group cannibalized quickly and the latency to cannibalize in these spiders was independent of body mass. We also tested if cannibalistic tendencies were higher among unrelated pairs than among pairs of siblings, but we did not find any support for this hypothesis. In another experiment we tested if maternal effects influenced cannibalism, i.e. if siblings from certain mothers were more cannibalistic than siblings from others. We did not find any evidence that maternal effects influenced whether or not cannibalism occurred. However, when cannibalism did occur, the latency to cannibalize varied significantly among siblings from different mothers beyond what would have been predicted solely from hatchling body mass.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Data on the biology of Alopecosa psammophila Buchar 2001 (Araneae, Lycosidae)

by Csaba Szinetár & János Eichardt:  Department of Zoology, Berzsenyi College, Károlyi Gáspár tér 4. Szombathely, H-9700 Hungary.  E-mail: szcsaba@bdtf.hu

Roland Horváth:  Department of Evolutionary Zoology and Human Biology, University of Debrecen, POB. 3, Debrecen, H-4010 Hungary

ABSTRACT.  This paper presents electron micrographs of the genitalia of Alopecosa psammophila, describes the morphological characteristics of the species and also gives information on its habitat preference, the co-occurring ground-dwelling spiders, and the phenological characteristics of the species. Barber pitfall trappings have been carried out since 2000 in dry sandy grasslands in three regions of Hungary: the Kiskunság area (Kiskunság National Park); the Nyírség area (Hortobágy National Park); and since 2004 the Kisalföld area (Fertő-Hanság National Park). Specimens of the species, hitherto unknown in Hungary, have been collected from 17 localities in all three areas. We collected specimens in calciferous open sand steppes and in acidic open sand steppes. In the females, two activity periods were apparent (from April to end July and in October). A few males were collected in April and in October--November they had an extreme activity peak. We assume that the species has adult specimens throughout the winter. Alopecosa psammophila is most similar to Xysticus ninni Thorell 1872 and Zelotes longipes (L. Koch 1866) in terms of its environmental needs.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


SIZE DEPENDENT INTRAGUILD PREDATION AND CANNIBALISM IN COEXISTING WOLF SPIDERS (ARANEAE, LYCOSIDAE)

by Ann L. Rypstra: Department of Zoology, Miami University, 1601 Peck Blvd. Hamilton, Ohio 45011 USA.  Email: RypstraL@muohio.edu  

Ferenc Samu: Department of Zoology, Plant Protection Institute, Hungarian Academy of Sciences, PO Box 102, Budapest, H-1525 HUNGARY 

ABSTRACTTwo species of wolf spider, Hogna helluo (Walckenaer 1837) and Pardosa milvina Hentz 1844 dominate the predatory community on the soil surface of agroecosystems in eastern North America. Although as adults they are very different in size, differences in phenology ensure that they overlap in size at various times during the year. In a laboratory experiment, we explored the propensity of each species to attack and kill the other wolf spider species (intraguild predation), conspecifics (cannibalism) or crickets (ordinary predation). Both spiders attacked and killed a broader size range of crickets more quickly than they approached other spiders. We found no differences in Hogna foraging on conspecifics or Pardosa, but Pardosa  attacked and killed Hogna more readily than conspecifics. Because Hogna was so slow in attacking other spiders, their impact as an intraguild predator may be quite small, especially if their approach to crickets is an indication of their predatory tendencies with insects. On the other hand, Pardosa attacked and killed small Hogna as readily as crickets, which suggests they may have an influence on Hogna populations if  Hogna young emerge coincident with large juvenile or adult Pardosa.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


REVIEW OF THE ORIENTAL WOLF SPIDER GENUS PASSIENA (LYCOSIDAE, PARDOSINAE)

by Pekka T. Lehtinen:  Centre for Biodiversity, University of Turku, 20014 Turku, Finland. E-mail: pekleh@utu.fi

ABSTRACTThe pardosinegenus Passiena Thorell 1890 is redefined and relimited. Passiena has excellent diagnostic characters, in particular the male pedipalp that carries a unique group of soft spicules on the distal part of the palea. The female of the type species, Passiena spinicrus Thorell 1890 from Malaysia, is illustrated for the first time. A new species, P. torbjoerni, is described from Thailand. All specimens of Passiena were collected from the ground layer of or nearby dense jungle or bush, an exceptional habitat for Oriental Pardosinae. Males of P. spinicrus carry modified setae on the ventral side of the abdomen, similar to Hygrolycosa rubrofasciata (Ohlert 1865) and Pardosa sphagnicola (Dahl 1908), where they play an important role in the courtship behavior of males. Five African species currently listed in Passiena do not conform to the generic diagnosis as provided here. Three of these show clear affinities with Pardosa C.L. Koch 1847 and are consequently transferred from Passiena: Pardosa praepes (Simon 1885); Pardosa elegantula (Roewer 1959) new combination; and Pardosa upembensis (Roewer 1959) new combination. Passiena auberti(Simon 1898) and Passiena albipalpis Roewer 1959 are considered incertae sedis pending a generic revision of African Lycosidae as they cannot be placed with certainty into any other lycosid genus.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


The function of long copulation in the wolf spider Pardosa agrestis (Araneae, Lycosidae) investigated in a controlled copulation duration experiment

by András Szirányi, Balázs Kiss, Ferenc Samu:  Plant Protection Institute of the Hungarian Academy of Sciences, P.O. Box 102. Budapest, H-1525 Hungary. E-mail: samu@julia-nki.hu

Wolfgang Harand: Bundesamt und Forschungszentrum für Landwirtschaft, Vienna, Austria.

ABSTRACT.  Copulation duration varies greatly in wolf spider species, ranging from a few seconds to several hours. In Pardosa agrestis (Araneae, Lycosidae), the most common ground dwelling spider in Central European fields, copulation typically takes more than two hours. Since long copulation is likely to entail certain costs, we address the question, “what is the function of long copulations?” We investigated the consequences of lengthy copulation in an experimental situation, where copulations either ended spontaneously, or were interrupted after 10 min, 40 min or 90 min. There was no difference in the number of offspring per female when treatments were compared and we conclude that ten minutes of copulation was sufficient to fertilize all the eggs of a female. Long copulations should therefore have other functions than securing the necessary amount of sperm for fertilization. We also found that neither the time until egg production after copulation, nor offspring size was affected by copulation duration. This suggests the lack of transfer of ejaculatory substances that would either stimulate the egg sac formation or increase the size of the spiderlings. We propose that prolonged copulations gain meaning in multiple mating situations and should play a role in sperm competition or other forms of sexual selection. The extra time may be used for copulatory courtship, or for the transfer of surplus sperm or other substances to manipulate the female’s willingness to copulate with other males, or to use sperm from them. These hypotheses remain to be tested in multiple mating experiments.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


LARVAL CHAETOTAXY IN WOLF SPIDERS (ARANEAE, LYCOSIDAE): SYSTEMATIC INSIGHTS AT THE SUBFAMILY LEVEL

by Beata Tomasiewicz:  Zoological Institute, Department of Biodiversity and Evolutionary Taxonomy, Przybyszewskego 63/77, 51-148 Wrocław, Poland. E-mail: beatatomas@interia.pl

Volker W. Framenau:  Department of Terrestrial Invertebrates, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia.

ABSTRACT.  Studies into the systematics of wolf spiders have mainly employed morphological characters of adult spiders, in particular features of the male and female genitalia, and more recently mitochondrial DNA sequence data. However, there is still no established phylogenetic framework for the Lycosidae, even at the subfamily level. This study uses a novel morphological character set, the chaetotaxy of lycosid larvae (presence and arrangement of setae and slit organs), to infer systematic information on seven species of wolf spiders that are currently listed in three subfamilies: Lycosinae [Alopecosa pulverulenta (Clerck 1757), Hogna antelucana (Montgomery 1904), Rabidosa rabida (Walckenaer 1837), Trochosa ruricola (DeGeer 1778)], Piratinae [Hygrolycosa rubrofasciata (Ohlert 1865), Pirata hygrophilus (Clerck 1757)], and Sosippinae (Sosippus californicus Simon 1898). Cheliceral and tarsal (legs I and II) chaetotaxic patterns of the first postembryo showed equivalent chaetotaxic complexes amongst all species but revealed considerable differences between representatives of the three subfamilies. Sosippus californicus showed the most complex pattern and P. piraticus the most reduced arrangement. In addition, it casts doubt on the previous listings of H. rubrofasciata in either the Lycosinae or Piratinae, as its chaetotaxic setae arrangement was more similar to S. californicus than to any other species investigated here.

 

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


A REDESCRIPTION OF PORRHOMMA CAVERNICOLA KEYSERLING (ARANEAE, LINYPHIIDAE) WITH NOTES ON APPALACHIAN TROGLOBITES

by Jeremy A. Miller: Department of Entomology, National Museum of Natural History, NHB-105, Smithsonian Institution, PO Box 37012, Washington, DC 20013-7012 U.S.A. E-mail: zmjeremy@gwu.edu

ABSTRACT.  The Appalachian troglobite Porrhomma cavernicola (Keyserling 1886) is redescribed. Porrhomma emertoni Roewer 1942 is a junior synonym (new synonymy). An unusual stridulatory organ with the plectrum on trochanter II and the striae on coxa I is found in both sexes of this species. Porrhomma cavernicola is widespread in Appalachian caves. By contrast, Appalachian nesticid troglobites tend to be highly endemic and syntopic. This despite the fact that both groups of spiders are web-builders that may be found in the same caves. Porrhomma cavernicola is added to a previous phylogenetic analysis of linyphiid spiders. Implications of this analysis for the phylogenetic structure of linyphiid spiders is discussed.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


The fossil spider family Lagonomegopidae in Cretaceous ambers with descriptions of a new genus and species from Myanmar

by David Penney:  Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom. E-mail david.penney@manchester.ac.uk

ABSTRACT.  The spider family Lagonomegopidae was described a decade ago from two specimens in Upper Cretaceous Siberian amber from the Taimyr Peninsula, and placed in the superfamily Palpimanoidea. Lagonomegopidae is known only from Cretaceous amber. Undiscovered extant species are considered unlikely because of their frequent occurrence in Cretaceous ambers and their absence in Tertiary fossil resins. One aim of this paper is to bring the existence of this family to the attention of neo-arachnologists. Burlagonomegops eskovi new genus and species is described from Cretaceous amber of Myanmar (Burma) and Lagonomegops americanus new species is assigned to a previously described, but unnamed specimen from Cretaceous New Jersey amber.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


THE GENERIC RELATIONSHIPS OF THE NEW ENDEMIC AUSTRALIAN ANT SPIDER GENUS NOTASTERON (ARANEAE, ZODARIIDAE)

by B.C. Baehr: Queensland Museum, P.O. Box 3300, South Brisbane Queensland 4101, Australia.
E-mail: BarbaraB@qm.qld.gov.au

ABSTRACTA revision of the new endemic Australian genus Notasteron revealed two species, Notasteron carnarvon new species (male), Notasteron lawlessi new species (female, male). The genus is characterized by a strongly reticulated, shield-shaped sternum with steep lateral margins and a posteriorly situated boss. The male palp has a semicircular and undulated distal tegular apophysis and the female epigyne has long, convoluted copulatory ducts. Possible relationships of Notasteron with genera of the Asteron ­complex, Habronestes, Hetaerica, Malinella and Storosa, are analyzed with NONA and also reconstructed using the Hennigian method. The results indicate that the new genus does not belong to the Asteron complex but is the sister genus of Hetaerica. Notasteron lawlessi is quite common and occurs throughout the eastern part of Australia, whereas N. carnarvon is only found in the Carnarvon region of Western Australia.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


TARSAL SCOPULA SIGNIFICANCE IN ISCHNOCOLINAE PHYLOGENETICS (ARANEAE, MYGALOMORPHAE, THERAPHOSIDAE)

by José Paulo Leite Guadanucci:  Museu de Zoologia da Universidade de São Paulo, Instituto de Biociências da Universidade de São Paulo, Av. Nazaré, 481, Ipiranga, CEP: 04263-000 São Paulo, SP – Brazil.
E-mail: zepaulo@artist.com.br

ABSTRACT.  Tarsal scopula condition and carapace length were studied for eighteen Ischnocolinae species. For cladistic analysis a matrix of 20 terminals and 30 characters of representatives of Ischnocolinae, Theraphosinae, Aviculariinae, Harpactirinae and Trichopelmatinae were analyzed using Nona 2.0 computer software. The matrix was analyzed in four different ways: 1. each tarsal scopula (legs I--IV) coded as separate characters; 2. one character with six ordered states; 3. one character with six independent states; 4. without tarsal scopula character. The first two matrices result in one tree with the same indices (L = 72; CI = 0.54; RI = 0.74) and topology: Part of Ischnocolinae is monophyletic (H. rondoni(S. longibulbi(I. algericus+Catumiri))) and the other representatives (Oligoxystre and Genus 1) form a distinct monophyletic group with Theraphosinae, Harpactirinae and Aviculariinae. There are no homoplasies in tarsal scopula evolution in the second cladogram. The other two cladograms show less resolution for the Ischnocolinae than the two first cladorams. The tarsal scopula condition appears to have no relation to spider size (t = -0.80433; P = 0.438247) and should be used in phylogenetic analysis of Ischnocolinae because it provides information on the character variability within the subfamily.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


 

A PRELIMINARY STUDY OF THE RELATIONSHIPS OF TAXA INCLUDED IN THE TRIBE POLTYINI (ARANEAE, ARANEIDAE)

by Helen M. Smith:  The Australian Museum, 6 College St, Sydney, New South Wales 2010, Australia and Faculty of Agriculture, Food and Natural Resources, The University of Sydney, New South Wales 2006, Australia.
E-mail: hsmith@austmus.gov.au

ABSTRACTPoltys and the genera Cyphalonotus, Homalopoltys, Ideocaira, Kaira, Micropoltys and Pycnacantha have historically been considered members of the tribe Poltyini. There is little published information on most members of the group and their potential relationships in the context of recent advances in araneid systematics. Information is sought on possible relatives of Poltys. All araneid members of the group except Pycnacantha were added to the data matrix compiled by Scharff & Coddington (1997), which already contained Kaira. Homalopoltys was found to be a tetragnathid when males were identified and was not considered further. The full data matrix of 74 taxa and 82 characters was run in PAUP* and NONA. The resulting placement of Poltys was not well supported but it frequently occurred in association with members of a slightly modified version of the ‘Hypsosinga’ clade of Scharff & Coddington, including Kaira. Cyphalonotus may be placed close to Araneus and Ideocaira may also belong in the same area of the araneines. Micropoltys may belong in the sister clade to these two.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


 

A FOSSIL HARVESTMAN (ARACHNIDA, OPILIONES) FROM THE MISSISSIPPIAN OF EAST KIRKTON, SCOTLAND

by Jason A. Dunlop: Institut für Systematische Zoologie, Museum für Naturkunde der Humboldt-Universität zu Berlin, Invalidenstraße 43, D-10115 Berlin, Germany.
E-mail: jason.dunlop@museum.hu-berlin.de

Lyall I. Anderson: Department of Natural Sciences, National Museums of Scotland, Chambers Street, Edinburgh, EH1 1JF, United Kingdom

ABSTRACT. A fossil harvestman (Arachnida, Opiliones) from the Mississippian (Viséan: Brigantian) of East Kirkton, Scotland is described as Brigantibunum listoni new genus and species. At ca. 340 Ma, it represents the second oldest record of Opiliones. Although some details are lacking, this long-legged, small-bodied and rather gracile harvestman is surprisingly modern-looking and appears to show the impression of an annulate ovipositor. Its leg anatomy closely matches that of some living Eupnoi and it is tentatively referred to this clade. Like the newly discovered Rhynie chert harvestmen, it reinforces the idea that modern, crown-group Opiliones can be traced back to at least the mid-Paleozoic.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


A REVISION OF THE SPIDER GENUS TAURONGIA (ARANEAE, STIPHIDIOIDEA) FROM SOUTH-EASTERN AUSTRALIA

by Michael R. Gray: Australian Museum, 6 College Street, Sydney, New South Wales 2010, Australia.
E-mail: mikeg@austmus.gov.au

ABSTRACTThe spider genus Taurongia Hogg 1901 and the species T. punctata (Hogg 1900) are redescribed. Taurongia punctata is shown to be a rather variable species with a widespread distribution across the eastern central Victorian highlands. Taurongia punctata is a robust spider, contrasting with a more gracile new species, T. ambigua, described from the western Victorian highlands. The placement of the latter in Taurongia is provisional and may change once other undescribed ‘Taurongia group’ genera from eastern Australia have been examined. The Taurongia species dealt with here differ from the latter taxa in having an increased number of cylindrical spigots and a large palpal median apophysis.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


 

REVISION OF SPIDER TAXA DESCRIBED BY KYUKICHI KISHIDA: PART 1. PERSONAL HISTORY AND A LIST OF HIS WORKS ON SPIDERS

by Hirotsugu Ono: Department of Zoology, National Science Museum, Tokyo, 3-23-1 Hyakunin-cho, Shinjuku-ku, Tokyo, 169-0073 Japan.
E-mail: ono@kahaku.go.jp

ABSTRACT. The personal history of forgotten Japanese arachnologist, Kyukichi Kishida (1888-1968) is described for the first time based on information collected from the literature and through interviews with the late Prof. Seikichi Kishida (1931-2002), the fourth son of K. Kishida. A complete list of Kishida's works on spiders is provided. Much confusion resulted from the species and higher taxa descriptions or species designations made by Kishida. In many cases he first proposed a new name for an undescribed species found but left its description to his followers. Therefore, some species were really described by another person, while many nomina nuda were produced. A revision of each taxon with systematical and nomenclatural problems will be given in forthcoming parts of this serial (in preparation).

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


FORAGING STRATEGIES OF ERIOPHORA EDAX (ARANEAE, ARANEIDAE): A NOCTURNAL ORB-WEAVING SPIDER

by Leonor Ceballos:  ECOSUR, AP 36, Tapachula, Chiapas, México

Yann Hénaut:  ECOSUR, AP 36, Tapachula, Chiapas, México. 
E-mail: yhenaut@tap-ecosur.edu.mx

Luc Legal:  LADYBIO - CNRS/UPS,118, route de Narbonne - bât. 4R3, 31062 Toulouse cedex 4 – France 

ABSTRACT.  Studies on the ecology of orb spiders have focused on diurnal spiders, especially field studies. Nocturnal spiders, however, face different conditions due to the type of prey found at night. A field study was conducted to observe the activity of adult females of Eriophora edax in their natural environment, and to analyze their predation efficiency and web retention properties. Most of the spiders were observed around sunset, which suggests that E. edax tends to build webs in the early evening. In order to evaluate the predation efficiency of E. edax we compared its behavior and web retention properties with the behavior of a diurnal orb-weaving spider, Verrucosa arenata. Two prey types, a diurnal Hymenoptera and a nocturnal Lepidoptera, were selected and presented to the spiders, to record approach time and prey capture time. The results showed that E. edax spent more time to capture Hymenoptera than to capture Lepidoptera. During the experiments of web prey retention time, Hymenoptera consistently showed greater tumbling than Lepidoptera, but the total retention time was the same for both prey types. Our results showed that E.edax forages strictly at night and, in terms of prey capture and web retention, was more efficient when preying on Lepidoptera.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


THE WASP SPIDER ARGIOPE BRUENNICHI  (ARACHNIDA, ARANEIDAE): BALLOONING IS NOT AN OBLIGATE LIFE HISTORY PHASE

by André Walter, Peter Bliss and Robin F.A. Moritz:  Institut für Zoologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, D-06120 Halle (Saale), Germany.
E-mail: bliss@zoologie.uni-halle.de

ABSTRACT.  Aerial dispersal (“ballooning”) of Argiope bruennichi spiderlings has been claimed to be an obligate life history trait and a prerequisite for spinning prey-capture webs. If this were true, a ballooning phase would be essential for any laboratory rearing of A. bruennichi making rearing protocols particularly elaborate. We tested the significance of ballooning for second-instar spiderlings in the laboratory and showed that the ballooning behavior is not essential for building prey-capture orb webs. Our results also give no evidence for the hypothesis that recent natural selection has changed ballooning behavior in newly founded field populations.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


CAN SIMPLE EXPERIMENTAL ELECTRONICS SIMULATE THE DISPERSAL PHASE OF SPIDER BALLOONERS?

by James R. Bell:  Warwick HRI, Wellesbourne, Warwickshire.  CV35 9EF
E-mail: j.r.bell@warwick.ac.uk

David A. Bohanand Richard Le Fevre:  Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ

Gabriel S. Weyman:  Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY

ABSTRACT.  Here we describe the structure of a fall speed chamber designed to measure, with low experimental error, the terminal velocities (fall speeds) of spiders of known weight and a given length of silk. We also describe the construction of a simulated individual (SI) which could later be used to estimate the distance travelled by ballooning spiders in the field. Our data and analysis suggest that Oedothorax spp. (Linyphiidae) and Pachygnatha degeeri (Tetragnathidae) individuals have fall speeds that can be described by their silk length and mass. Of the observed deviance in the fall speeds, 73.7% could be explained by a GLM model common to both species groups. Overlaying the SI fall speed data on this GLM surface suggests that the SIs have similar fall speed behaviors to spiders. However, further estimation is necessary before SIs could be considered valid models for evaluating spider ballooning distances.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Nocturnal navigation in Leucorchestris arenicola (Araneae, sparassidae)

by Thomas Nørgaard:  Department of Zoology, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich, Switzerland. E-mail: thomasn@drfn.org.na

ABSTRACT.  When the males of the Namib Desert spider Leucorchestris arenicola (Araneae, Sparassidae) reach the adult stage they undertake long nocturnal searches for females. From these searches they return to their home burrow often in a straight line only retracing a fraction of their outward path if at all. Distances of 40 m and 13 m are conservative estimates of the mean round trip length and maximum distance from the burrow. Returning to the starting point of a round trip of such length is theoretically only possible if the navigator uses external cues for positional reference. The possible involvement of a range of external cues in the male L. arenicola was investigated. The direction of gravity, the sun, polarized sunlight, olfaction, constant wind direction and vibrational beacons are ruled out or deemed unlikely to be involved in the spiders’ homing.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Use of Anopheles-specific prey-capture behavior by small juveniles of Evarcha culicivora, a mosquito-eating jumping spider

by Ximena J. Nelson (1,2) Robert R. Jackson (2,3) and Godfrey Sune (3)

(1) Department of Psychology, Animal Behaviour Laboratory, Macquarie University, Sydney, NSW 2109, Australia.
E-mail: ximena@galliform.bhs.mq.edu.au
(2) School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. 
(3) International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya.

ABSTRACT.  The prey-capture behavior of the juveniles of Evarcha culicivora, an East African mosquito-eating jumping spider, was investigated in the laboratory using living prey and using dead, motionless lures made from two mosquito species, Anophelesgambiaesenu stricta and Culex quinquefasciatus. Having tested individuals of E. culicivora that had no prior experience with mosquitoes (rearing diet: only chaoborid and chironomid midges), our findings imply that the small, but not the large, individuals of E. culicivora have an innate predisposition to adopt Anopheles-specific prey-capture behavior. Findings from lure tests implicate posture as a primary cue by which the small juveniles of E. culicivora identify Anopheles. Each individual of E. culicivora was presented with two lures, one in the posture typical of Anopheles and the other in the posture typical of Culex. Small, but not large, juveniles of E. culicivora often responded to Anopheles mounted in the Anopheles posture and Culex mounted in the Anopheles posture by taking a route or a detour to the prey which enabled the salticid to approach the lure from behind. However, detours were not routine for small or for large individuals of E. culicivora when the lure, whether made from Anopheles or Culex, was in the Culex posture. When tested with live mosquitoes, small juveniles of E. culicivora were more effective at capturing Anopheles than Culex. Large juveniles were more effective than small E. culicivora juveniles at capturing Culex, but large and small juveniles had similar success at capturing Anopheles.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


EGG SAC STRUCTURE OF ZYGIELLA X-NOTATA(ARACHNIDA, ARANEIDAE)

 by T. Gheysens (1), L. Beladjal1, K. Gellynck (2), E. Van Nimmen (2),  L. Van Langenhove (2) & J. Mertens (1)

(1) Ghent University, Department of Biology, Terrestrial Ecology, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium. 
E-mail: Tom.Gheysens@UGent.be
(2) Ghent University, Department of Textiles, Technologiepark 9, B-9052 Zwijnaarde, Belgium

 ABSTRACT.  A detailed examination of the egg sac of Zygiella x-notata (Clerck 1757) revealed its structure, composition and different fibers. All egg sacs were composed of a basic layer, an insulation layer and an outer layer. The insulation layer consisted of two layers of cylindrical (or tubuliform) fibers with different diameters and probably with different mechanical properties. Knowing the complete structure of the egg sac allows us to locate and extract the needed fibers for further research and to observe how the egg sac composition alters in relation to the habitat.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


NOTES ON THE NATURAL HISTORY OF A TRAPDOOR SPIDER ANCYLOTRYPA SIMON (ARANEAE, CYRTAUCHENIIDAE) THAT CONSTRUCTS A SPHERICAL BURROW PLUG

by Astri Leroy and John Leroy:  PO Box 390, RUIMSIG, 1732, South Africa. E-mail: astri@jml.co.za

ABSTRACT.  Burrows of an unidentified species of Ancylotrypa Simon from the floodplain of the Nyl River in Limpopo Province, South Africa are described. In addition to constructing a thin trapdoor, members of this species construct a hard, spherical plug or marble from soil particles held together with silk. Burrow structure, the plug and associated behavior are described for the first time.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


THE SPERMATOZOA OF THE ONE-PALPED SPIDER TIDARREN ARGO (ARANEAE, THERIDIIDAE)

by Peter Michalik (1), Barbara Knoflach (2), Konrad Thaler (2), Gerd Alberti (1)  
(1) Zoologisches Institut und Museum, Ernst-Moritz-Arndt-Universität, J.-S.-Bach-Straße11/12, D-17489 Greifswald, Germany
(2) Institut für Zoologie und Limnologie, LeopoldFranzens-Universität, Technikerstraße 25, A-6020 Innsbruck, Austria

ABSTRACT.  The species of the genus Tidarren are known for their one-palped males and outstanding copulatory behavior. In our ultrastructural observations of T. argo Knoflach & van Harten 2001, we show that this species possesses highly specific spermatozoa which differ from those found in other spiders: The nucleus of the sperm cell is strongly elongated and characterized by a conspicuous implantation fossa. The basis of the axoneme is located close to the acrosomal complex. The axoneme starts in front of the implantation fossa which extends deeply into the postcentriolar elongation. The implantation fossa is filled with dense staining globules and granules as in other theridiid species. Apart from these peculiarities, in T. argo the proximal centriole is located extraordinarily far away from the distal one. The encapsulated cleistospermia are surrounded by a thin secretion sheath. Remarkably, mature spermatozoa are not densely packed, but embedded in a copious secretion.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


ON THE OCCURRENCE OF THE 9 + 0 AXONEMAL PATTERN IN THE SPERMATOZOA OF SHEETWEB SPIDERS (LINYPHIIDAE, ARANEAE)

by Peter Michalik and Gerd Alberti:  Zoologisches Institut und Museum, Ernst-Moritz-Arndt-Universität, J.-S.-Bach-Straße 11/12, D-17489 Greifswald, Germany.
E-mail: michalik@uni-greifswald.de

ABSTRACT.  In general, flagella and cilia of eukaryotes show an axoneme composed of a 9 + 2 microtubular pattern. However, the axoneme of spider spermatozoa is characterized by an exceptional 9 + 3 microtubular pattern, which is known as a synapomorphy of the Megoperculata (Amblypygi, Uropygi and Araneae). In contrast to all other observed spiders, the axoneme of the linyphiid spider Linyphia triangularis, was shown to lack the central microtubules thus representing a 9 + 0 axoneme. In the present study, we investigated the spermatozoa from several linyphiid species of different genera in order to show whether this peculiar pattern also occurs in other linyphiid spiders. Interestingly, in all observed species (Neriene clathrata, N. peltata, Linyphia hortensis, Lepthyphantes sp., Oedothorax gibbosus, Gongylidium rufipes and Drapetisca socialis) we found the 9 + 0 microtubular pattern in the axoneme. Since this study, although considering still a very limited number of species, includes species from Linyphiinae (Linyphiini and Micronetini) and Erigoninae it seems likely that this pattern is an autapomorphy of Linyphiidae.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


Evidence for directional selection on male abdomen size in Mecolaesthus longissimus Simon (Araneae, Pholcidae)

by Bernhard A. Huber:  Zoological Research Institute and Museum Alexander Koenig, Adenauerallee 160, 53113 Bonn, Germany, E-mail: b.huber.zfmk@uni-bonn.de

ABSTRACT.   Abdomens of male Mecolaesthus longissimus Simon 1893 are on average more than twice as long as in females, their length is highly variable, and they show extremely steep allometric values when scaled on body size (OLS, b = 2.64). Males cohabit with females, and they likely fight to defend this position as other pholcid spiders do. Male legs, which are usually used in pholcid male-male fights, do not show the usual high allometric values but a very low value (OLS, b = 0.37). Collectively, this lends support to the idea that M. longissimus males do not use their legs in fights and that male abdomens have assumed a role in male-male fights. However, behavioral data are missing and sexual selection by female choice or inter-male display might be involved. A large sample of data from taxonomic revisions is used to document that across pholcids, males consistently have longer tibiae 1 (and probably legs in general) than females. Several possible reasons have been suggested to account for longer male than female legs in various spider groups, but the pattern in pholcids remains to be explained.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


EFFECTS OF PREY QUALITY ON THE LIFE HISTORY OF A HARVESTMAN

by Aino Hvam & Søren Toft:  Department of Ecology & Genetics, University of Aarhus, Denmark, Bldg. 135 DK-8000 Århus C, Denmark.

ABSTRACTInformation on the value of various food types for harvestmen is sparse. The aim of this study was, therefore, to clarify the quality of six different food types to a harvestman. Survival, growth and development were used as measures of fitness in a laboratory experiment. Recently hatched Oligolophus tridens were fed the following experimental diets until maturity: Drosophila melanogaster (Diptera), entomobryid Collembola (Tomocerus bidentatus/Sinella curviseta), Folsomia candida (Collembola), Sitobion avenae (Aphidoidea), Rhopalosiphum padi (Aphidoidea), and a mixed diet containing the five prey types. Survival and growth rate were high on the D. melanogaster and entomobryid diets, and low on the F. candida, S. avenae and R. padi diets. The mixed diet caused a high early mortality, later a good survival and a high growth rate. The majority of harvestmen on the D. melanogaster and entomobryid diets matured. None of the harvestmen fed pure aphid diets developed beyond the fourth instar, and only few from the F. candida diet matured. Overall, the diets separate in three levels: D. melanogaster and the entomobryid diet were high-quality, the mixed diet was intermediate, and the two aphid diets and F. candida diet were low-quality. In general, the quality ranking agrees with that of other generalist predators, though there are differences in details.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


 

CHROMOSOMAL DATA OF TWO PHOLCIDS (ARANEAE, HAPLOGYNAE): A NEW DIPLOID NUMBER AND THE FIRST CYTOGENETICAL RECORD FOR THE NEW WORLD CLADE

by Douglas de Araujo (1), Antonio Domingos Brescovit (2), Cristina Anne Rheims (2,3) and Doralice Maria Cella1

(1) Universidade Estadual Paulista - UNESP, Instituto de Biociências, Departamento de Biologia, Av. 24-A, 1515, CEP.: 13506-900, Bela Vista, Rio Claro, SP, Brazil.
E-mail: daraujo@rc.unesp.br and
dmcella@rc.unesp.br
(2) Instituto Butantan, Laboratório de Artrópodes Peçonhentos, Av. Vital Brasil, 1500, CEP.: 05530-900, São Paulo, SP, Brazil.
(3) Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil.

ABSTRACT. Mesabolivar luteus (Keyserling 1891) and Micropholcus fauroti (Simon 1887) specimens were collected in Ubatuba and Rio Claro, both in the state of São Paulo, Brazil. Mesabolivar luteus showed 2n (male) = 15 = 14 + X and 2n (female) = 16 = 14 + XX in mitotic metaphases and 7II + X in diplotenic cells. During late prophase I, all bivalents presented a ring shape, evidencing two chiasmata per bivalent. In this species, some diplotenic cells appear in pairs, maybe due to specific characteristics of the intercellular bridges. The metaphases II showed n = 7 or n = 8 = 7 + X chromosomes. Micropholcus fauroti evidenced 2n (male) = 17 = 16 + X in spermatogonial metaphases and 8II+X in diplotenic cells, with only one chiasma per bivalent, contrasting with M. luteus. In both species, all chromosomes were metacentrics. The sexual chromosome X was the largest element and appeared as a univalent during meiosis I. These are the first cytogenetical data for the genera Mesabolivar and Micropholcus. Additionally, M. luteus is the first chromosomally analyzed species of the New World clade and the observed diploid number for M. fauroti had not yet been recorded in Pholcidae.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


SIX STRIDULATING ORGANS ON ONE SPIDER (ARANEAE, ZODARIIDAE): IS THIS THE LIMIT?

by Rudy Jocqué:  Royal Museum for Central Africa, Leuvensesteenweg 13, B-3080 Tervuren, BELGIUM.
E-mail: rudy.jocque@africamuseum.be

ABSTRACT.   A new type of stridulatory organ is described and figured occurring in three species of Mallinella Strand from Thailand and Singapore. In one species there are four stridulatory organs, with the ridges on femora I and II and the pegs in the shape of granulations on femora II and III. In both the other species an additional pair occurs, with ridges on femora III and pegs on femora IV. To date no more than four stridulatory organs have been recorded on a single spider. Examples of various known forms of stridulatory organs on spiders are illustrated and their significance briefly discussed.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


FIRST ULTRASTRUCTURAL OBSERVATIONS ON THE TARSAL PORE ORGAN OF PSEUDOCELLUS PEARSEIAND P. BONETI (ARACHNIDA, RICINULEI)

by Giovanni Talarico (1), Jose G. Palacios-Vargas (2), Mariano Fuentes Silva (2) & Gerd Alberti1

(1) Zoological Institute & Museum, Ernst-Moritz-Arndt-University Greifswald, J.-S.-Bach-Str. 11/12, D-17489 Greifswald, Germany.
Email: g.talarico@gmx.net
(2) Laboratorio de Ecología y Sistemática de Microartrópodos, Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, UNAM, México.

ABSTRACT.   Due to their relative rareness and restricted distribution, little is known about the ultrastructure of ricinuleids. In particular, sense organs have not been the subject of electron microscopic research until now. Ricinuleids use their forelegs to explore their surroundings with tentative movements. The distal tarsomeres of legs I and II of two cavernicolous Mexican species, Pseudocellus pearsei from the Yucatán Peninsula and Pseudocellus boneti from Guerrero, were examined in this study with light microscopy, scanning (SEM) and transmission electron microscopy (TEM). A conspicuous feature of the distal tarsomeres of legs I and II is a single circular opening that extends as a deep tube-like pit into the tarsus. This pore organ is lacking in the 6-legged larvae. Comparable organs are present in Araneae, Scorpiones, Amblypygi and Anactinotrichida. The tarsal organs of the mentioned groups possess several types of sensilla (olfactory, thermo- and hygrosensitive and mechanosensitve). The pore organ is located in the distal third of the dorsal half of the tarsus. In longitudinal sections it shows a long oval shape. In cross sections it is nearly circular. The pore organ contains a large number of long, slightly curved setae. These setae are localized on the bottom and the lower two thirds of the wall of the pit and project into the lumen. The upper third of the wall is free of setae and shows folds which extend parallel to the opening. All setae inside the pit seem to be of the same type. In sections they show a complex inner structure and likely represent chemoreceptive wall pore single-walled (wp-sw) sensilla. This indicates a possible olfactory function. The pore organ is underlain by numerous gland cells which represent characteristics of unicellular “class I” gland cells.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


ULTRASTRUCTURE OF MALE GENITAL SYSTEM AND SPERMATOZOA OF A MEXICAN CAMEL-SPIDER OF THE EREMOBATES PALLIPES SPECIES GROUP  (ARACHNIDA, SOLIFUGAE)

by Anja E. Klann (1), Alfredo V. Peretti (2)and Gerd Alberti1

(1) Zoological Institute & Museum, Ernst-Moritz-Arndt-University Greifswald, Johann-Sebastian-Bach-Straße 11/12, D-17489 Greifswald, Germany.
Email: anja.klann@uni-greifswald.de
(2) CONICET - Cátedra de Diversidad Animal I, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Vélez Sarsfield 299, C. P. 5000, Córdoba, Argentina

ABSTRACT.  The male genital system of Solifugae is divided into three different parts: a) a common genital chamber, b) the paired tubular vasa deferentia and c) the long, thin testes. On each side, the vas deferens splits into two smaller branches resulting in the thin, extremely long testes such that one individual possesses four tubular testes in total. The epithelium of a testis consists mainly of a glandular part and of a germinal part surrounded by a small layer of muscles. In Eremobates sp., within the germinal part the sperm cells are groups of a few, probably four, mature sperm cells each surrounded by thin extensions of somatic cells. These somatic cells can clearly be distinguished from the cells forming the glandular part which contain large amounts of rough endoplasmic reticulum. Once released into the narrow testicular lumen, the spermatozoa float more or less individually in a proteinaceous secretion. Earlier stages of spermatogenesis could not be detected, suggesting that spermatogenesis may occur in the subadult male (not examined in this study). In general, the sperm is rather simple, representing a round or slightly elongated cell devoid of a flagellum. The relatively small and flat acrosomal vacuole is attached to the disc-like nucleus. The acrosomal filament penetrates the nucleus and is coiled several times around it. In contrast to species of the family Ammotrechidae or Karschiidae, for which sperm cells have already been described, the sperm cells of the Mexican Eremobates sp., which belongs to the family Eremobatidae, show no tendency to form any piles or well ordered groups in the lumen of either the testes or the vasa deferentia.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue


TERGAL AND SEXUALANOMALIES IN BOTHRIURID SCORPIONS (SCORPIONES, BOTHRIURIDAE)

Camilo I. Mattoni:  Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA. 
E-mail: cmattoni@amnh.org

ABSTRACT.  New data concerning developmental anomalies observed among species of the family Bothriuridae (Scorpiones) are presented. Tergal malformations in Bothriurus coriaceus,Brachistosternus roigalsinai and Bothriurus noa are described and illustrated. Two new cases of intersexuality in scorpions, in specimens of Brachistosternus pentheri and Bothriurus araguayae, are reported and discussed.

 Download a copy of this article

Go to the top of this page

Go to Contents for this Issue

 


Modeling of the stress-strain behavior of EGG SAC silk of the spider Araneus diadematus 

by Els Van Nimmen & Kris Gellynck:  Department of Textiles, Ghent University, Technologiepark 907, B-9052 Zwijnaarde, Belgium. E-mail: Els.VanNimmen@UGent.be

Tom Gheysens:  Department of Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium

Lieva Van Langenhove:  Department of Textiles, Ghent University, Technologiepark 907, B-9052 Zwijnaarde, Belgium

Johan Mertens:  Department of Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium

ABSTRACT.  Spider silk has attracted the attention of many scientists because of its desirable physical properties. Most of this attention has been devoted to dragline silk, a thread that has high tensile strength, high strain and ultra-low weight. To help understand structure-property relationships in spider silks, the tensile behavior of egg sac (cylindrical gland) silk of Araneus diadematus Clerck 1757 was compared with dragline (major ampullate gland) and silkworm silks. In addition, stress-strain curves of egg sac silk were simulated by a spring-dashpot model, specifically a Standard Linear Solid (SLS) model. The SLS model consists of a spring in series with a dashpot and in parallel with another spring, resulting in three unknown parameters. The average stress-strain curve of fibers from five different egg sacs could be accurately described by the model. Closer examination of the individual stress-strain curves revealed that in each egg sac two populations of fibers could be distinguished based on the parameters of the SLS model. The stress-strain curves of the two populations clearly differed in their behavior beyond the yield point and were probably derived from two different layers within the egg sac. This indicates that silks in the two layers of A. diadematus egg sacs probably have different tensile behavior.

  Download a copy of this article

Go to the top of this page

Go to Contents for this Issue

 


Go to:

This page was posted 12 / 29 / 2005 and modified for open access on 2 / 8 / 2007; modified for tracking 11 / 27 / 2009