Abstracts to Articles

The Journal of Arachnology

Volume 30 Number 3

LINYPHIA TRIANGULARIS, A PALEARCTIC SPIDER (ARANEAE, LINYPHIIDAE) NEW TO NORTH AMERICA

by Daniel T. Jennings: USDA, Forest Service, Northeastern Research Station, 686 Government Road, Bradley, Maine 04411 USA
Kefyn M. Catley: Rutgers, The State University of New Jersey, 10 Seminary Place, New Brunswick, New Jersey 08901-1183 USA
Frank Graham, Jr.: National Audubon Society, 700 Broadway, New York, NewYork 10003 USA

ABSTRACT. A Palearctic spider, Linyphia triangularis (Clerck 1757), has been accidentally introduced to the U.S.A. and populations successfully established in Maine. The date, origin, and focal point(s) of introduction are unknown, but suspected to be recent, European, and maritime. Extensive historical collections, records of maritime commerce, and recent chronological collections support this hypothesis. Results of cursory surveys in 1999 and 2000 indicate that L. triangularis is now widely distributed in Maine with specimens taken in 15 of 16 counties. The potential impact(s) of L. triangularis on the native araneofauna are unknown, but possibly detrimental. In Europe, this species exhibits aggressive behaviors (e.g., web "take-overs") toward conspecifics and congenerics.

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INFLUENCE OF FEEDING REGIME ON BODY SIZE, BODY CONDITION AND A MALE SECONDARY SEXUAL CHARACTER IN SCHIZOCOSA OCREATA WOLF SPIDERS (ARANEAE, LYCOSIDAE): CONDITION-DEPENDENCE IN A VISUAL SIGNALING TRAIT

by George W. Uetz, Randi Papke, and Beril Kilinc: Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006. e-mail: George.Uetz@uc.edu

ABSTRACT. Male Schizocosa ocreata (Hentz) wolf spiders (Araneae, Lycosidae) have tufts of elongated, dark bristles on the patella and tibia of the forelegs, which are involved in visual signaling. Previous research has suggested that these tufts are used by females as a criterion in mate choice, raising the question of whether they might serve as indicators of male condition. We tested the hypothesis that tufts are condition-dependent indicator traits with a laboratory rearing study subjecting spiders to lifelong feeding regimens representing successful (high food) and unsuccessful (low food) foraging history, after which males were measured upon reaching adulthood. Mortality varied significantly with experimental treatment, and had a disproportionate impact on some egg sacs assigned to the low food treatment. Age at sexual maturity and several body size measures varied significantly with feeding history. Well-fed spiders survived better, matured earlier, were significantly larger, and were in relatively better condition (measured as a residual body condition index) than deprived spiders. Additionally, well-fed spiders had significantly larger relative tuft size (scaled for body size). These data suggest that male body size, condition and a conspicuous male signaling trait vary with feeding history, and thus have the potential to serve as "honest indicators" of male quality in mate choice.

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THE FIRST OLD WORLD SPECIES OF PHRYNIDAE (AMBLYPYGI): PHRYNUS EXSUL FROM INDONESIA

by Mark S. Harvey: Department of Terrestrial Invertebrates, Western Australian Museum, Francis St, Perth, Western Australia 6000, Australia

ABSTRACT. A new species of Phrynus, P. exsul, from the Indonesian island of Flores, represents the first member of the family found outside of the New World.

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MALE PEDIPALPAL STRIDULATORY DEVICES IN NEOTROPICAL WOLF SPIDERS AND THEIR POSSIBLE ROLE IN SYSTEMATICS

by C. Fernández-Montraveta: Dpto. Psicología Biológica y de la Salud, Universidad Autónoma de Madrid, Spain. Email: carmen.montraveta@uam.es

M. Simó: Sección de Entomología, Facultad de Ciencias, Universidad de la República, Uruguay

ABSTRACT. In males of several Uruguayan lycosid species of the genera Lycosa, Schizocosa, Aglaoctenus and Allocosa, we used scanning electron microscopy to investigate the existence and the morphology of pedipalpal stridulatory-like structures. These kinds of structures only appeared in species belonging to the subfamily Lycosinae, and representatives of the Allocosinae and Sosippinae subfamilies lacked them altogether. Unlike European Lycosa species, all surveyed Uruguayan species of the genus Lycosa presented the character to some extent, but interspecific differences occurred in the relative size and development of the structure. Lycosa thorelli, L. carbonelli and Lycosa sp. showed a very well developed pedipalpal structure, which was smaller in Lycosa poliostoma. Schizocosa malitiosa also exhibited an only partially developed structure. A possible role of these pedipalpal stridulatory-like structures in lycosid systematics is discussed.

RESUMO. Mediante Microscopía Electrónica de Barrido, hemos analizado la existencia y la morfología de las estructuras pedipalpales de tipo estridulador en los machos de varias especies uruguayas de la familia Lycosidae (géneros Lycosa, Schizocosa, Aglaoctenus y Allocosa). Este tipo de estructuras sólo está presente en especies pertenecientes a la subfamilia Lycosinae, mientras que las especies representativas de las subfamilias Allocosinae y Sosippinae carecen por completo de ellas. A diferencia de las especies europeas de Lycosa, todas las especies uruguayas del género analizadas presentan la estructura, aunque existen diferencias interespecíficas en su tamaño y desarrollo relativos. Lycosa thorelli, L. carbonelli y L. sp. presentan una estructura pedipalpal muy bien desarrollada, mientras que su tamaño es menor en Lycosa poliostoma. Schizocosa malitiosa también posee una estructura sólo parcialmente desarrollada. Discutimos una posible aplicación de estas estructuras en la sistemática de la familia Lycosidae.

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EVIDENCE THAT THE WOLF-SPIDER LYCOSA TARENTULA (ARANEAE, LYCOSIDAE) NEEDS VISUAL INPUT FOR PATH INTEGRATION

by Joaquìn Ortega-Escobar: Department of Biological Psychology, Faculty of Psychology, University Autónoma of Madrid, 28049-Madrid, Spain. Email: joaquin.ortega@uam.es

ABSTRACT. The homing behavior of Lycosa tarentula (Linnaeus 1758) (Araneae, Lycosidae) adult females was studied. They were tested under two conditions, diffused light (200 lux) and darkness, after having been placed in an open field. In both conditions the spiders did not orient towards the burrow position; instead, under diffused light, each spider turned at a constant angle with a value close to135º; this is the turn that the spider should have made in its terrarium to return to the burrow. In darkness, most of the spiders (71.4%) turned at random. In both conditions, the trajectory was roughly straight, finishing with a sudden directional change. The speed was higher under diffused light than under darkness. These results support the hypothesis that L. tarentula uses path integration in laboratory conditions and that it needs visual input to obtain a direction estimation in homing.

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THE OLDEST LINYPHIID SPIDER, IN LOWER CRETACEOUS LEBANESE AMBER (ARANEAE, LINYPHIIDAE, LINYPHIINAE)

by David Penney and Paul A. Selden: Earth Sciences, University of Manchester, Manchester, M13 9PL, UK. E-mail: david.penney@man.ac.uk

ABSTRACT. A new fossil Linyphiidae: Linyphiinae is described from 125­135 Ma old (Upper Neocomian­basal Lower Aptian) Cretaceous amber from the Kdeirji/Hammana outcrop, Lebanon. This is the oldest known linyphiid as well as the oldest described amber spider. The first major radiation of the linyphiid subfamilies occurred in the early Cretaceous, if not before, and the presence of Linyphiidae in this period predicts the presence of Pimoidae then too. Current evidence, which suggests the higher araneoids did not radiate and diversify until after the end-Cretaceous mass extinction event may be an artefact of sample size.

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ESTIMATING THE STICKINESS OF INDIVIDUAL ADHESIVE CAPTURE THREADS IN SPIDER ORB WEBS

by Brent D. Opell: Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 USA. E-mail: bopell@vt.edu

ABSTRACT. Sticky threads improve an orb web's ability to retain the insects that strike it, allowing a spider more time to subdue these insects before they can escape from the web. The adhesive capture threads found in most orb webs feature small droplets of aqueous material. Inside each droplet, glycoprotein granules coalesce to impart thread stickiness. An independent contrast analysis of threads produced by the adults of five species (Leucauge venusta, Argiope trifasciata, Micrathena gracilis, Cyclosa conica, Araneus marmoreus) and ontogenetic studies of the threads of two of these species show that the volume of material in a thread's droplets is directly related to its stickiness. Models based on these analyses predict thread stickiness to within an average of 11% of the mean measured values using measurements of droplet diameter and distribution that are easily made with a compound microscope. This approach will facilitate the inclusion of thread stickiness in studies that examine the properties and performance of spider orb-webs.

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A COMPARATIVE STUDY OF PHENOLOGY AND DAILY ACTIVITY PATTERNS IN THE WOLF SPIDERS PARDOSA MILVINA AND HOGNA HELLUO IN SOYBEAN AGROECOSYSTEMS IN SOUTHWESTERN OHIO (ARANEAE, LYCOSIDAE)

by Samuel D. Marshall, Daniel M. Pavuk and Ann L. Rypstra: Miami University, 1601 Peck Boulevard, Hamilton, OH 45011

ABSTRACT. We studied the phenology and the daily activity patterns of Pardosa milvina Hentz 1844 and Hogna helluo (Walckenaer 1837) in replicated soybean fields in southwest Ohio over three years (1994--1996) using pitfall traps. For the phenology study we established an array of five pitfall traps in 12 replicate 0.42 ha fields. These traps were either set for two days at two-week intervals (1994), or for three days at three-week intervals (1995 & 1996), over the field season from May--October on 20 trap dates each year. We found that P. milvina was more common overall, and found evidence for one population peak per year. Numbers of H. helluo tended to be lowest in the earlier censuses, and we found evidence for one peak of male activity per year. The immature male and female, and adult female, H. helluo were larger (based on carapace width) than the immature male and female, and adult female, P. milvina on most trapping dates. For the circadian activity periodicity study we used two different drift-fence trap designs, both with dry-cup pitfall traps set for two or three days and checked at 12 h intervals. For three sampling periods in 1994 we found H. helluo to be more frequently trapped at night, and for two sampling periods P. milvina was more frequently trapped during the daylight hours.

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MATING SUCCESS AND ALTERNATIVE REPRODUCTIVE STRATEGIES OF THE DIMORPHIC JUMPING SPIDER, MAEVIA INCLEMENS (ARANEAE, SALTICIDAE)

by David L. Clark (1) and Brandon Biesiadecki (1,2):

1. Department of Biology, Alma College, Alma, MI 48801, U.S.A. E-mail: clarkd@alma.edu
2. Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, US.A.

ABSTRACT. The two male morphs of the dimorphic jumping spider, Maevia inclemens, differ dramatically in morphology and courtship behavior.The purpose of this study was to examine and compare the mating success of the two male types. Mating success was measured by the number and duration of copulation events, the latency of visual orientation by the female to a courting male, signals of female receptivity, risk of predation by the female, and the number of offspring produced by each morph. The morphs did not differ significantly with respect to copulation success, mating events, mating duration, signals of receptivity or the number of offspring produced. However, males did differ with respect to latency of visual orientation as a function of distance from the female. Near to the female, the gray males attracted female attention in significantly less time than tufted males. Conversely, at far distances from the female, the tufted males attracted female attention in less courtship time. This study suggests that males attain equal levels of mating success and that the two male morphs may have evolved alternative reproductive strategies for courtship at different distances from the female.

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THE FIRST MYGALOMORPH SPIDER WITHOUT SPERMATHECAE: SICKIUS LONGIBULBI, WITH A REVALIDATION OF SICKIUS (ARANEAE, THERAPHOSIDAE, ISCHNOCOLINAE)

by Rogerio Bertani and Pedro Ismael da Silva Junior: Laboratório de Artrópodes, Instituto Butantan, Av. Vital Brazil 1500, São Paulo, São Paulo, 05503-900, Brazil. Email: rbert@usp.br.

ABSTRACT. The monotypic Brazilian genus Sickius Soares & Camargo 1948 is revalidated, rediagnosed, and tentatively transferred to the Ischnocolinae. The formerly unknown female of S. longibulbi Soares & Camargo 1948 is found to lack spermathecae. This unusual genital feature, not found in any other mygalomorph spider species, is described and discussed.

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KEYS TO THE GENERA OF ARANEID ORBWEAVERS (ARANEAE, ARANEIDAE) OF THE AMERICAS

by Herbert W. Levi: Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138-2902, USA E-mail: herblevi@mac.com

ABSTRACT. This paper contains keys to the 65 genara of araneid spiders known from the Americas. These genera hold approximately fifteen hundred species found in the Americas. The key to females uses mostly artificial character; the key to males uses diagnostic characters. There are four new synonyms and two new placements.

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FOUR NEW SPECIES OF THE GENUS LEPTONETA (ARANEAE, LEPTONETIDAE) FROM TAIWAN

by Ming-Sheng Zhu: College of Life Sciences, Hebei University, Baoding 071002, China

I-Mn Tso: Department of Biology, Tunghai University, Taichung 407, Taiwan Division of Zoology, National Museum of Natural Science, Taichung 404, Taiwan

ABSTRACT. The new species Leptoneta changlini, L. huisunica, L. nigrabdomina and L. taiwanensis are described and illustrated from Taiwan, and the natural history of L. changlini and L. huisunuca is described. These species are only known from male specimens.

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REPRODUCTIVE BIOLOGY OF URUGUAYAN THERAPHOSIDS (ARANEAE, MYGALOMORPHAE)

by Fernando G. Costa: Laboratorio de Etología, Ecología y Evolución, IIBCE, Av. Italia 3318, Montevideo, Uruguay. E-mail:fgc@iibce.edu.uy

Fernando Pérez-Miles: Sección Entomología, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay

ABSTRACT. We describe the reproductive biology of seven theraphosid species from Uruguay. Species under study include the Ischnocolinae Oligoxystre argentinense and the Theraphosinae Acanthoscurria suina, Eupalaestrus weijenberghi, Grammostola iheringi, G. mollicoma, Homoeomma uruguayense and Plesiopelma longisternale. Sexual activity periods were estimated from the occurrence of walking adult males. Sperm induction was described from laboratory studies. Courtship and mating were also described from both field and laboratory observations. Oviposition and egg sac care were studied in the field and laboratory. Two complete cycles including female molting and copulation, egg sac construction and emergence of juveniles were reported for the first time in E. weijenberghi and O. argentinense. The life span of adults was studied and the whole life span was estimated up to 30 years in female G. mollicoma, which seems to be a record for spiders. A comprehensive review of literature on theraphosid reproductive biology was undertaken. In the discussion, we consider the lengthy and costly sperm induction, the widespread display by body vibrations of courting males, multiple mating strategies of both sexes and the absence of sexual cannibalism.

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COURTSHIP AND SPERM TRANSFER IN THE WHIP SPIDER PHRYNUS GERVAISII (AMBLYPYGI, PHRYNIDAE): A COMPLEMENT TO WEYGOLDT´S 1977 PAPER

by Alfredo V. Peretti: CONICET- Cátedra de Diversidad Animal I, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba. Avda. Vélez Sarsfield 299 (5000), Córdoba, Argentina. E-mail: aperetti@com.uncor.edu

ABSTRACT. The aim of this study was to provide descriptive and quantitative data regarding behaviors involved in courtship and in sperm transfer of the whip spider Phrynus gervaisii (Pocock 1894) in order to complete the previous description for this same species given by P. Weygoldt. The specimens were captured in anthills of Paraponera clavata, on Barro Colorado Island, Panama. Ten courtship and five sperm transfer sequences were recorded. Four out of five mating sequences with sperm transfer ocurred between adults with similar body size and in the other case the female was smaller than the male. Sexual interactions did not occur between very small adults. Two male behavior patterns that have not been reported were observed during the initial stage of courtship: "pedipalp rubbing" and "female operculum rubbing". Contrary to Weygoldt´s description, in this study the female never performed "shaking" movements with her antenniform legs. It was observed that the two distal horn-like extensions of the spermatophore facilitate the female´s movements during the sperm transfer. The distal part of the spermatophore stalk provides a suspension area when the female rests on those horns. It was verified that the female can move the claw-like sclerites of the gonopods in all directions. The male executed copulatory courtship and successfully transferred sperm in five analyzed sequences. The female did not pick up the sperm packages when copulatory courtship was not performed. Males that lacked one antenniform leg were able to mate, however they had to perform vibrations more intensely with their non-injured leg for a longer duration. The data are compared with those previously obtained in other whip spiders. Some functional characteristics of the spermatophore and female genitalia of P. gervaisii are also discussed.

RESUMEN. El objetivo de este trabajo es aportar datos descriptivos y cuantitativos sobre patrones de comportamiento que ocurren durante el cortejo y transferencia espermática del amblipígido Phrynus gervaisii (Pocock 1894) con la finalidad de completar la descripción previa de P. Weygoldt para esta misma especie. Los especímenes fueron capturados en hormigeros de Paraponera clavata, en la Isla de Barro Colorado, Panamá. Se registraron 10 secuencias de cortejo y cinco de transferencia espermática. Cuatro de las cinco secuencias de apareamiento con transferencia espermática completa ocurrieron entre adultos de tamaño corporal similar mientras que en el otro caso la hembra fue más pequeña que el macho. No se produjeron interacciones sexuales entre adultos muy pequeños. Durante la etapa inicial del cortejo fueron observados dos patrones de comportamiento masculinos que no habían sido citados con anterioridad: "roces de pedipalpos" y "roces al opérculo genital femenino". Al contrario de la descripción de Weygoldt, en el presente estudio la hembra nunca realizó movimientos de "latigueo" con sus patas anteniformes. Se observó que las dos expansiones distales con forma de cuerno del espermatóforo facilitan los movimientos de la hembra durante la transferencia espermática. La parte distal del tallo del espermatóforo ofrece un área de suspensión cuando la hembra se apoya sobre estos cuernos. Se verificó que la hembra puede mover los escleritos en form de uña de sus gonópodos hacia todas las direcciones. El macho efectuó cortejo copulatorio en cinco secuencias analizadas, en ellas la transferencia espermática fue existosa. Por el contrario, la hembra no recogió los paquetes espermáticos cuando no existió cortejo copulatorio. Los machos que carecían de una pata anteniforme también fueron capaces de aparear. Sin embargo, ellos tuvieron que realizar más intensamente las vibraciones con sus patas no dañadas, y sobre todo durante un tiempo más prolongado para evitar que la hembra se alejara. Se comparan los datos aquí registrados con aquellos previamente obtenidos en otros amblipígidos. Se discuten algunas características funcionales del espermatóforo y genitalia femenina de P. gervaisii.

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ORIENTATION AND MOVEMENT OF WOLF SPIDERS PARDOSA LAPIDICINA (ARANEAE, LYCOSIDAE) IN THE INTERTIDAL ZONE

by Douglass H. Morse: Department of Ecology and Evolutionary Biology, Box G-W, Brown University, Providence, RI 02912 USA. Email: d_morse@brown.edu

ABSTRACT. Wolf spiders, Pardosa lapidicina Emerton 1885, occupy cobble beaches along the tide line about Narragansett Bay, Rhode Island, USA, and move back and forth on the beaches with the tides. I compared the orientation and movement in the low intertidal of three groups with normal access to the entire intertidal zone and a group from the high intertidal prevented from using the low intertidal by a barrier of dense salt-marsh cordgrass Spartina alterniflora. They included a group captured in the high intertidal (High), one captured in the low intertidal (Low), one from the low intertidal but not captured (Observed), and one captured behind cordgrass (Cordgrass) . The High group moved farther and more unidirectionally than the others, and the Cordgrass group exhibited the most variable orientation of the manipulated spiders. All groups exhibited a roughly southwesterly orientation from the release site. The Low and Observed groups moved shorter distances than the others, and High individuals appeared more strongly inclined to leave the low intertidal than individuals initially positioned there (Low, Observed). Thus, experience likely played a role in the orientation and movement of the spiders.

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SHORT COMMUNICATION:

A NEW OGRE-FACED SPIDER (DEINOPIS) FROM THE GAOLIGONG MOUNTAINS, YUNNAN, CHINA (ARANEAE, DEINOPIDAE)

by Chang-Min Yin: College of Life Science, Hunan Normal University, Changsha, Hunan Province 410081, P. R. China
Charles E. Griswold: California Academy of Sciences, San Francisco, California 94118, USA
Heng-Mei Yan: College of Life Science, Hunan Normal University, Changsha, Hunan Province 410081, P. R. China

ABSTRACT. The present paper describes Deinopis liukuensis new species, from the Gaoligong Mountains, Yunnan Province, China. This is the first mature deinopid described from China.

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SHORT COMMUNICATION:

FEEDING IN MAXCHERNES IPORANGAE (PSEUDOSCORPIONES, CHERNETIDAE) IN CAPTIVITY

by Renata de Andrade and Pedro Gnaspini: Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11461, 05422-970 São Paulo, SP, Brazil. E-mail: gnaspini@ib.usp.br

ABSTRACT. The feeding behavior of the cave pseudoscorpion Maxchernes iporangae Mahnert & Andrade 1998 was studied in the laboratory. We also investigated aspects such as preference and frequency. Nymphs are more active in prey capture. Cannibalism is uncommon. The frequency of feeding of adults was about once a month, with an increased rate for females during the reproductive period.

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SHORT COMMUNICATION:

NOTES ON THE NATURAL HISTORY AND HUNTING BEHAVIOR OF AN ANT EATING ZODARIID SPIDER (ARACHNIDA, ARANEAE) IN COLORADO

by Paula E. Cushing: Department of Zoology, Denver Museum of Nature & Science, 2001 Colorado Blvd., Denver, CO 80205-5798 USA
Richard G. Santangelo: 3803 Holly Lane, Raleigh, North Carolina 27612 USA

ABSTRACT. The ant hunting behavior of Zodarion rubidum (Araneae, Zodariidae) is described from specimens collected in Colorado, USA. Like other members of this genus, Z. rubidum constructs igloo-shaped stone retreats under rocks and feeds on ants. Details of the prey capture behavior are provided including initial and subsequent reactions of ants to the bites of Z. rubidum and data on the time it takes for ants to become completely paralyzed as a result of the bites.

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