Abstracts to Articles

The Journal of Arachnology

Volume 28 Number 1

 

THE FAMILY GALLIENIELLIDAE (ARANEAE, GNAPHOSOIDEA) IN THE AMERICAS

Pablo A. Goloboff: Consojo Nacional de Investigaciones Cientificas y Tecnicas, Instituto Miguel Lillo, Miguel Lillo 205, 4000 S. M. de Tucuman, Argentina

ABSTRACT. Azilia leucostigma Mello-Leitao 1941 considered by Mello-Leitao as a metine (Tetragnathidae), is transferred to the gnaphosoid family Gallieniellidae, as the type species of the new genus Galianoella. The obliquely depressed endites, the flattened irregular postenor median eyes, and the conical anterior lateral spinnerets retaining a sclerotized distal ring, among other characters, clearly place the new genus in the family Gallieniellidae. Galianoella leucostigma is the only gallieniellid so far recorded fom the Americas. This species has a specialized ant-preying behavior. Ant-preying may prove to be characteristic for all the family, as it was suspected in the Madagascan Gallieniella; and it may be associated with the modified chelicerae typical of the family.

Keywords: Spiders, arachnids, Galianoella


The Journal of Arachnology 28: 1-6

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DESCRIPTIONS AND NOTES ON THE GENUS PARADOSSENUS IN THE NEOTROPICAL REGION (ARANEAE, TRECHALEIDAE)

Antonio D. Brescovi (1) Josue Raizer and Maria Eugenia C. Amaral (2)
(1) Lab. Artropodes Peconhentos, Instituto Butantan, Av. Vital Brasil, 1500, CEP 05503-900, Sao Paulo, SP, Brazil
(2) Depto de Biologia, Centro de Ciencias Biologicas e de Saude, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil, C. Postal 549, CEP 79070-900

ABSTRACT. Three Brazilian species of the genus Paradossenus F.0. Pickard-Cambridge 1903 are included in this paper: Paradossenus minimus (Mello-Leitao 1940), whose holotype was located and is here redescribed; Paradossenus corumba new species is described from Mato Grosso do Sul, Brazil and preliminary data on its biology are presented. Morphological data and new records of P. longipes (Taczanowski 1874) are included.

Keywords: Paradossenus, Trachaleidae, Araneae, Neotropical region

The Journal of Arachnology 28:7-15

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OPTICAL STRUCTURE OF THE CRAB SPIDER MISUME:NOPS PALLENS (ARANEAE, THOMISIDAE)

Jose Antonio Corronca: CRILAR-CONICET-UNLaR. Mendoza esq. Entre Rios. (5301) Anillaco, La Rioja, Argentina

Hector R. Teran: Instituto de Morfologia Animal, Fundacion Miguel Lillo. Miguel Lillo 251. (4000) S.M. de Tucuman, Argentina

ABSTRACT. We describe the histological structure of the eyes of Misumenops pallens (Araneae, Thomisidae). We have camed out frontal, sagittal and transverse histological sections of the eyes. All the eyes have cuticular and laminar comeas and lenses. The antenor median eyes have two cellular types in the rhabdom; the remaining eyes have three cellular types. The anterior median eyes have a dark pigmented U-shaped mark in the middle of the retina. The indirect eyes have a dark pigmented band divided by a grate tapetum. The pathway of the optic nerves is also described. Our results suggest that Thomisidae may be a close relative of the superfamily Lycosoidea.

RESUMEN. Se describe la estructura histol6gica de los ojos de Misumenops pallens (Araneae, Thomisidae). Se realizaron cortes de los ojos en seccidn frontal, sagittal y transversal. Todos los ojos tienen cdmeas y lentes cuticulares y laminares. Los ojos medios anteriores tienen dos tipos celulares en el rabdoma mientras que los restantes ojos tienen tres tipos celulares. Los ojos medios anteriores poseen, en el centro de la retina, una mancha de pigmento oscuro en fomma de U. Los ojos de visidn indirecta tienen una banda oscura de pigmento dividida por un tapete de tipo "grate." Se estudia tambien el recorrido de los nervios 6pticos. Nuestros resultados sugieren que Thomisidae puede estar relacionado con la superfamilia Lycosoidea.

Keywords: Eyes, optic nerves, phylogenetic relationship

The Joumal of Arachnology 28:16 22

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MALE DIMORPHISM IN OEDOTHORAX GIBBOSUS (ARANEAE, LINYPHIIDAE): A MORPHOMETRIC ANALYSIS

Stefan Heinemann and Gabriele Uhl: University of Bonn, Institute of Zoology, Department of Ethology, Kirschallee 1, D-53115 Bonn, Germany

ABSTRACT. The linyphiid spiders Oedothorax gibhosus (Blackwall 1841) and Oedothorax tuberosus (Blackwall 1841) were formerly descnbed as separate species due to marked differences in prosomal structures of the males. Dunng the last decade it was demonstrated that they are two forms of a single species. However, it remained to be shown whether the fommer species represent two distinct morphs or extremes of a continuum of variation. A morphometric examination of 246 alcohol-preserved specimens revealed that individual spiders can clearly be assigned to one of two forms. No intermediates were found, demonstrating that there are two distinct morphs.

 

Keywords: Species status, polymorphism, morphometry, sexual selection, gustatorial courtship

The Joumal of Arachnology 28:23-28

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MALE PALPAL BULBS AND HOMOLOGOUS FEATURES IN THERAPHOSINAE (ARANEAE, THERAPHOSIDAE)

Rogerio Bertani: Laboratorio de Artropodes, Instituto Butantan; Av. Vital Brazil 1500, Sao Paulo, Sao Paulo, 05503-900, Brazil

ABSTRACT. A first attempt to homologize male palpal bulb structures of theraphosine spiders is made, with the aim of providing systematic characters. The morphology and distribution of palpal bulb keels of over 60 species in 27 genera of Theraphosinae is presented and discussed Four basic groups of keels were recognized and a terminology was created to name them: prolateral inferior and prolateral superior keels, for the two more or less parallel keels found on the prolateral bulb face; apical keel, for the ventral keel located just before the apex of the embolus; subapical keel, for a keel located just before the apical keel; and, retrolateral keel, for the keel located on the retrolateral region, originating on the apical region and extending backwards. Other palpal bulb keels, apart from these four basic groups, as well as other structures, were found in some genera and/or species, constituting apomorphies for these groups.

Keywords: Theraphosidae, male palpal bulbs, morphology of genitalia, systematics, homology

The Journal of Arachnology 28:29-42

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EXPLORING FUNCTIONAL ASSOCIATIONS BETWEEN SPIDER CRIBELLA AND CALAMISTRA

Brent D. Opell, Jamel S. Sandidge and Jason E. Bond: Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 USA

ABSTRACT. A spider's calamistrum draws silk fibrils from its cribellum and helps combine them with supporting strands to fomm a cubellar prey capture thread. Despite the close functional association of these two features, this study shows that there is a great deal of variability in the ratio of cnbellum width to calamistrum length. When the independent contrast method was used to examine these two features in 11 species representing seven families, no relationship was found. Likewise, no relationship was found among nine species representing seven genera of the family Uloboridae. Only among the 14 species of Mallos (Dictynidae) was calamistrum length directly related to cribellum width. This suggests that, above the genus level, differences in spinning behavior and morphological features such as leg length and abdomen size and shape influence the relationship of these two features.

Keywords: cribellar thread, cubellate spiders, independent contrast method, functional linkage

The Journal of Arachnology 28:43-48

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CHARACTERIZATION OF LIPOPROTEINS ISOLATED FROM THE HEMOLYMPH OF THE SPIDER LATRODECTUS MIRABILIS (ARANEAE, THERIDIIDAE)

Monica Cunningham (1), Alda Gonzalez (2) and Ricardo Pollero (1)
(1) Instituto de Investigaciones Bioquimicas de La Plata (INIBIOLP), Facultad de Ciencias Medicas, 60 y 120 (1900) La Plata, Argentina
(2) CEPAVE. Facultad de Ciencias Naturales y Museo, 1900 La Plata, Argentina

ABSTRACT. Two high density lipoprotein fractions (HDL1 and HDL2) were isolated from the hemolymphatic plasma of the spider Latrodectus mirahilis (Holmberg 1876) For each, the hydrated density, the electrophoresis mobility of the apoproteins, and the lipid classes composition were determined. The HDL1 fraction carried 80% of the total plasma lipids, which were predominantly composed of phospholipids, free fatty acids, and triacylglycerols. The apoprotein composition of this fraction showed two main bands of 90 and 103 kDa. The HDL2 fraction was composed primarily of phospholipids, free fatty acids and cholesterol. This fraction contained hemocyanin as the principal apoprotein. When the HDL2 fraction was separated into three subfractions, all of them contained hemocyanin, with the main subfraction containing the hexameric form of the respiratory pigment. With regard to triacylglycerol transport, lipid and apoprotein compositions and hemocyanin role in the lipid transport, these lipoproteins (HDL1, HDL2) show similarities and differences when compared to the two spider species already studied.

Keywords: Lipoproteins, Latrodectus, hemolymph

The Joumal of Arachnology 28:49-55

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DIET-INDUCED AND MORPHOLOGICAL COLOR CHANGES IN JUVENILE CRAB SPIDERS (ARANEAE, THOMISIDAE)

Victoria R. Schmalhofer: Graduate Program in Ecology and Evolution, Department of Ecology, Evolution, and Natural Resources, Rutgers University, Cook College, 14 College Farm Road, New Brunswick, New Jersey 08901-8551 USA

ABSTRACT. The effect of dietary pigments on abdominal color of juvenile spiders was examined in the laboratory using the flower-dwelling crab spiders Misumenops asperatus (Hentz 1847), Misumenoides formosipes (Walckenaer 1837), and Misumena vatia (Clerck 1757) (Thomisidae). Because these species lack hypodermal chromes, ingested prey pigments may show through the epidermis and affect opisthosomal coloration. Diet-induced color changes were restricted to the opisthosoma, and all three spider species responded similarly to dietary pigments. Opisthosomas of instars 2-4 fed red-eyed fruit flies turned pink, and the pink color faded back to the normal white over a penod of 4-6 days. Opisthosomas of instars 5-7 fed red-eyed fruit flies remained white, as did opisthosomas of all instars fed white-eyed fruit flies (controls). In a field population of M. asperatus, 82% of spiders in July (instar 2), 93% of spiders in August (instars 3-4), and 8% of spiders in September (instar 5) had pink, orange, or brown opisthosomas. Yellow juveniles were also seen: 5% and 57% of M. asperatus observed in August and September, respectively, were yellow. Yellow juvenile M. formosipes were observed in the field as well. The yellow color did not result ffom dietary pigments, but was, rather, a morphological color change and included the prosoma and limbs, as well as the opisthosoma.

Keywords: Flower spiders, opisthosoma, prey pigments, size-dependent effect

The Journal of Arachnology 28:56 60

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COSTS AND BENEFITS OF FORAGING ASSOCIATED WITH DELAYED DISPERSAL IN THE SPIDER ANELOSIMUS STUDIOSUS (ARANEAE, THERIDIIDAE)

Thomas C. Jones and Patricia G. Parker: Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 1735 Neil Ave., Columbus, Ohio 43210 USA

ABSTRACT. In the theridiid spider, Anelosimus studiosus, most juveniles remain in their natal web, forming temporary colonies in which individuals cooperate in web maintenance and prey capture until they disperse at matunty. There is natural variation in age at dispersal, and subadult spiders removed from their natal webs build webs and continue to develop To explore the costs and benefits of delayed dispersal, we compared the rate of prey capture and developmental rate for individuals in colonies and those isolated at the fourth instar rate of prey capture by colonies increased with colony size and age; this result was driven primarily by the enhanced capture of large prey by larger and older colonies. The presence of juveniles increased the overall productivity of webs, an effect which remained after the juveniles were removed from the web. Despite the overall increase in prey capture, per-individual prey capture decreased with colony size. The variance in prey capture success decreased significantly with colony size, but not with colony age. Spiders in colonies captured more prey per juvenile than singletons experimentally dispersed at the fourth instar; however, this did not result in increased development rate of colonial juveniles over isolated juveniles. These data suggest that juvenile A. studiosus benefit from delayed dispersal by acquiring more resources and acquiring them more steadily. The productivity of webs of females whose juveniles were removed at the fourth instar remained higher than those of similarly aged females who never produced juveniles. This suggests that delayed dispersal of juveniles enhances the resources which the female could allocate to her next egg mass.

Keywords: Parental investment, sub-sociality, risk-sensitivity, cooperative foraging

The Joumal of Arachnology 28:61-69

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RESOURCE PARTITIONING OF SPIDER HOSTS (ARACHNIDA, ARANEAE) BY TWO MANTISPID SPECIES (NEUROPTERA, MANTISPIDAE) IN AN ILLINOIS WOODLAND

Kurt E. Redborg and Annemarie H. Redborg: Department of Biology, Coe College, Cedar Rapids, Iowa 52402 USA

ABSTRACT. Two spider-boarding mantispids, Mantispa ublen Banks 1943 and Climaciella brunnea (Say 1824), were found to be partitioning available spider egg resources in an 111inois woods based on vertical stratification Mantispa uhleri was found to be phoretic on the philodromid Philodromus vulgans (Hentz 1847), the salticid Metacyrba undata (De Geer 1867) and the anyphaenid Aysha gracilis (Hentz 1847) at levels of 75%,26%, and 27% respectively. All of these spiders were collected from areas above the forest floor. In contrast, C. brunnea was collected from 19% of leaf litter-inhabiting Iycosids of the genus Schizocosa. There was no host range overlap within the woods, but in a grassy field without appreciable stratification of vegetation adjacent to the woods, both M uhleri and C. brunnea were found aboard the lycosid Rabidosa punctulata (Walckenaer 1837) at levels of 2% and 7% respectively A single larva of Mantispa pulchella (sanks 1912) associated with an anyphaenid from the woodland sample was also collected in this study. Mantispids are far more common than has been previously supposed and are likely an important factor in spider population dynamics and the evolution of spider behavior.

Keywords: Mantispa ubleri, Climaciella brunnea, Mantispa pulchella

The Journal of Arachnology 28:70-78

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EFFECTS OF FERTILIZER ADDITION AND DEBRIS REMOVAL ON LEAF-LITTER SPIDER COMMUNITIES AT TWO ELEVATIONS

Angel J. Vargas: Department of Biology, University of Puerto Rico, P.O. Box 23360, San Juan, Puerto Rico 00931-3360 USA

ABSTRACT. This study investigates the indirect effects of primary productivity enhancement via fertilization, and the direct effects of environmental differences at two elevations, on the density and species richness of leaf-litter spiders. Litter was sampled in tabonuco forest (340-360 m elevation) and elfin forest (1051 m elevation) within the Luquillo Expenmental Forest Long Term Ecological Research (LTER) site in Puerto Rico. Treatments consisted of three blocks with fertilization and control plots at both sites, and a one time removal of humcane generated debus at tabonuco forest only. Treatments had no significant effect on spider density, species diversity, and species richness at either elevation. Elfin forest showed lower densities and lower species richness than tabonuco forest due to harsh environmental conditions. The thin litter layer and similar standing litter in the tabonuco forest suggest that spiders are limited by habitat, and also that they have successfully recolonized the debris cleared areas at this elevation. Harsh environmental conditions at elfin forest seem to be strong enough to counteract the effects of fertilizer addition on the measured variables. However, the high biomass of grasses in the fertilization plots at elfin forest could have caused an underestimation of spider densities. This study suggests that habitat availability is an important variable in bottom-up models for food web link control.

Keywords: Leaf-litter community, species diversity, primary productivity enhancement, tabonuco forest, Puerto Rico

The Journal of Arachnology 28:79-89

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A TWENTY-YEAR COMPARISON OF EPIGEIC SPIDER COMMUNITIES (ARANEAE) OF DANISH COASTAL HEATH HABITATS

Peter Gajdos (1,2) and Soren Toft (1)
(1) Department of Zoology, Institute of Biological Sciences, University of Aarhus, Universitetsparken, Building 135, DK-8000 Aarhus, Denmark
(2)1nstitute of Landscape Ecology, Bratislava, Branch Nitra, Slovak Academy of Sciences, Akademicka 2,.POB -23B, 949 01 Nitra, Slovak Republic

ABSTRACT. The same epigeic spider communities of Northwest Jutland coastal heath habitats (Denmark, region Thy) initially surveyed by pitfall traps from 1977-79 were examined 20 years later (199798). The heath plots were open sandy areas growing into Calluna heath, and the more stable Erica, CallunalEmpetrum, Molinia vegetation types They have changed vegetatively only a little in those 20 years from natural succession. Though the spider communities of all areas showed only minor changes from the passage of time, these were larger than the differences attributable to the different habitat types despite large differences in soil humidity and vegetation structure.

Keywords: Spiders, community composition changes, coastal heathland habitats, Denmark

The Joumal of Arachnology 28:90-96

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HABITAT DISTRIBUTION, LIFE HISTORY AND BEHAVIOR OF TETRAGNATHA SPIDER SPECIES IN THE GREAT SMOKY MOUNTAINS NATIONAL PARK

Marie Aiken and Frederick A. Coyle: Department of Biology, Western Carolina University, Cullowhee, North Carolina 28723 USA

ABSTRACT. Habitat distnbution patterns of five species of Tetragnatha Latreille 1804 were studied by analyzing 1163 one-hour samples collected at 17 focal sites representing 16 major biotic communities (habitats) in the Great Smoky Mountains National Park. Tetragnatha versicolor Walckenaer 1841 is a habitat generalist, being common over a wide range of elevations (520-1755 m) and in 10 of the 16 habitats, including seven forest habitats as well as wetland, high grass bald, and grassland habitats. Tetragnatha laboriosa Hentz 1850 is virtually restricted to non-wetland grassy habitats, T elongata Walckenaer 1805 to streams, T. viridis Walckenaer 1841 to hemlock trees, and T. straminea Emerton 1884 to non-forested wetlands (marshes). Microhabitat segregation exists in the high grass bald community between T. versicolor (prefers trees and shrubs) and T lahoriosa (prefers herbs). Size frequency histograms of seasonal samples of T. straminea specimens indicate that this species has a one-year life cycle with six post-emergent instars, and that most individuals overwinter in the antepenultimate instar and mature and mate in May and June. Tetragnatha straminea is able to capture prey with or without using a web and adopts stick-like cryptic postures in three different contexts.

Keywords: Tetragnatha, spider, habitat preference, life cycle, cryptic behavior

The Journal of Arachnology 28:97-106

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SPIDER BIODIVERSITY IN CONNECTION WITH THE VEGETATION STRUCTURE AND THE FOLIAGE ORIENTATION OF HEDGES

Frederic Ysnel and Alain Canard: Laboratoire de Zoologie et d'Ecophysiologie, UMR CNRS 6553, Universite de Rennes I, Campus de Beaulieu, 35042 Rennes Cedex, France

ABSTRACT. The relationship between the structure of spider communities and an index of hedge ecological quality (based on an analysis of vegetation architecture using vegetation diversity and foliage cover) was investigated. The comparison deals with six hedges each of low, medium and high ecological value. The species richness and species composition of dominant spiders was the same for hedges of different quality. Thus it is concluded that these two simple parameters cannot reflect the diversity of the hedge foliage. Indicating species of the differences between ecological quality of two hedges could be required among the groups of species absent from one type of hedge. However, the foliage onentation of the hedges may induce substitution of spider species; thus special attention must be paid to the foliage orientation when comparing the spider communities inhabiting the hedges.

Keywords: Foliage cover, foliage onentation, species richness

The Joumal of Arachnology 28:107-114

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EFFECT OF RIVER FLOW MANIPULATION ON WOLF SPIDER ASSEMBLAGES AT THREE DESERT RIPARIAN SITES

Erik J. Wenninger: Department of Biology, University of Toledo, Toledo, Ohio 43606 USA
William F. Fagan: Department of Biology, Arizona State University, Tempe, Arizona 85287- 1501 USA

ABSTRACT. The distribution, abundance, and diversity of wolf spider (Lycosidae) assemblages were investigated via pitfall trapping at three sites near Granite Reef Dam outside Phoenix, Arizona. These three sites featured different moisture and temperature regimes due to the dam, which diverts the Salt River into an urban canal system. Site I was a natural riparian area above the dam along the Salt River, Site 2 was adjacent to a man-made diversion canal, and Site 3 was adjacent to the dry riverbed below the dam. Four Iycosid species were found at Site 1, with Pardosa vadosa Barnes 1959 dominating. Two species each, though very few total individuals, were found at Sites 2 and 3. Simpson s index of diversity (of Iycosids and of all other terrestrial arthropods) was higher for Site I than for Sites 2-3. Prey availability was comparable among sites, but Site I had significantly higher relative soil moisture levels and less extreme substrate and air temperature conditions than did Sites 2 and 3. Spider abundance at each site was independent of prey availability, but instead depended chiefly upon moisture and temperature regimes among sites. The results suggest that wolf spiders experienced a significant effect from disturbance of their habitat by the dam, and that abiotic habitat attnbutes such as moisture and temperature may be more important for wolf spider abundance than prey availability alone in desert nparian systems.

Keywords: Pardosa, Salt River, Arizona

The Journal of Arachnology 28:115-122

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This page was posted 12 / 19 / 2000 and modified 11 / 27 / 2009