DOCSLIB.ORG

How Spiders Make a Living

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
How Spiders Make a Living Fonuu How Spiders Make a Living M. NYFFELER, W. L. STERLING, aNo D. A. DEAN Department of Entomology, Texas A&M University, College Station, TX77843 Environ. Entomol. 23(6): 1357-1367 (1994) ABSTRACT Although the beneffcial status of the spiders as insectivores has been widely recognized for quite some time, biologists by and large seem to be rather unfamiliar with the speciffc feeding habits of this very diverse order. We present an overview of the feeding patterns of 10 groups of common agroecosystem spiders to inform entomologists and ecologists concerned with issues of natural biological control. The various spider groups discussed in this article exhibit a very diverse range of life styles and foraging modes, which is reflected in the diversity of their feeding patterns. Implications of the insectivorous activities ofthese predators for natural pest control are discussed. KEY WORDS spiders, predation, diets Sprorns (AneNner) ARE a very diverse order of ingest solid food and must, therefore, inject di- ubiquitous carnivores within the class Arach- gestive enzymes into the immobilized prey (ex- nida. At the present time, >30,000 species of ternal digestion) and then suck in the dissolved spiders are described (Coddington & Levi 1991). tissue in liquid form. Spiders generally have a Over 3,000 species occur in North America alone very low rate of metabolism compared with other (Young & Edwards 1990). The vast majority of poikilothermic organisms of comparable body spiders occupy terrestrial habitats. Some ly- weight (Greenstone & Bennett 1980). They can cosids and pisaurids, however, can walk and sail store energy and starve for considerable time on the water surface (and at times even dive and periods, which makes them excellent survivors swim under water); they forage on aquatic and under conditions of food shortage (see Nyffeler & semiaquatic organisms when they inhabit Breene I990a). marshes, flooded rice fields, and other wetlands According to traditional foraging theory, spi- (Greenstone 1979, Oraze & Grigarick 1989, Zim- ders are considered to be predators of live, mov- merrnann & Spence 1989). One agelenid species ing prey only (e.g., Turnbull 1960, 1973). More (the water spider) actually lives under water (see recent studies have modiffed this view when ev- subsection Foraging Patterns of Web Weaoers). idence was found that spiders utilize a much Most spiders are highly cannibalistic solitary broader range of foraging strategies, including creatures and practice bizarre courtship rituals feeding on arthropod eggs (oophagy), dead ani- (Tumbull 1973). Several species produce sounds mals (scavenging), plant pollen, and even ar- (acoustic communication) during courtship and tiffcial diets (see McDaniel & Sterling 1982, agonistic displays (Rovner 1975,Uetz & Stratton Nyffeler et al. 1990a). Stealing ofprey from other 1982). These animals live in a world full of vi- spiders (kleptoparasitism) plays an important brations (e.g., Rovner & Barth l98l). Sexual di- role as an alternative foraging strategy ofvarious morphism occurs in many species, the female web spinners (Vollrath f987). Spiders have been normally being significantly larger than the male reported feeding on a wide range of different (hereafter adult length always refers to the fe- animal groups including some unusual prey such male). Spiders disperse by walking on the as small mice, bats, birds, ffsh, crayfish, crabs, ground, by using silk-thread bridges between frogs, lizards, snakes, and scorpions (Nyffeler & plants, as well as ballooning through the atmo- Benz 1981, McCormick & Polis 1982); however, sphere from place to place on silken threads in general they tend to concentrate on insect (Foelix 1982, Dean & Sterling 1985, Young & prey and to a lesser degree on other spiders Edwards 1990). All spiders produce silk from (Wise 1993). Most spider species forage on mul- abdominal glands though only the useb weaoers tiple prey species (generalist predators), which construct webs that are used to catch prey. Spi- Greenstone (1979) has suggested may be advan- ders are equipped with a pair ofjaws (chelicerae) tageous by optimizing a balanced essential and possess venom glands (exception, Ul- amino acid composition in the diet. Spiders feed oboridae do not produce venom). Immobiliza- predominantly on small-sized prey relative to tion of prey is assisted by the use of silk and by their own size (prey length s predator length) the injection of venom. These animals cannot (Nyffeler & Benz 1981, Wise 1993); feeding ex- OO46-225X/941 1357-1367$02.00/0 @ 1994 Entomological Socie9 of America This article is the copyright property of the Entomological Society of America and may not be used for aqy commercial or other private purpose without specific r,rnitten permission of the Entomological Society of America r358 ENvrnoNurrvrer, EurouolocY Vol.23, no.6 periments with a variety of spider species and a Swiss Federal Institute of Technology, respec- model prey (crickets) conducted in the labora- tively. tory revealed that the optimal prey length ranges from 50-80Vo of the spider length (Nentwig re87). Results and Discussion Spiders are among the numerically dominant Foraging Patterns of Web Weavers. High feed- insectivores in terrestrial ecosystems and exhibit ing frequencies (up to 90Vo spiders feeding si- a vety diverse range of life styles and foraging multaneously during peak activity) were ob- behaviors (Turnbull 1973, Wise 1993). Two basic served in ffeld populations ofcertain larger-sized groups of foraging strategies can be distin- orb weavers (Araneidae) that rebuild (recycle) guished: (I) web spöders (i.e., foraging with a their webs daily (Nyffeler 1982). The high feed- catching web) (Tables l-5), and (2) hunters or ing frequencies indicate that the web is a very wanderers (i.e., foraging without the use of a efficient prey capturing device. Large orb weav- web) (Tables 6-9). Some prominent representa- ers often kill prey in excess of their energy re- tives of web spinning spiders are orb weavers quirements. As many as 1,000 small insects have (Araneidae and Tetragnathidae), sheet web been found entangled at one time in a single orb weavers (Linyphiidae), mesh web weavers (Dic- web; however, not all insects caught by the web tynidae), comb-footed spiders (Theridiidae), and are eaten. Sheet-web weavers, mesh web weav- funnel-web weavers (Agelenidae). Prominent ers, comb-footed spiders, and funnel-web weav- representatives of hunters are wolf spiders (Ly- ers that do not renew their nets daily, feed cosidae), lynx spiders (Oxyopidae), crab spiders less frequently (<IlVo spiders feeding simul- (Thomisidae), and jumping spiders (Salticidae). taneously) (M.N. & Benz 1988a; unpublished These I0 families are among the most abundant data). Relatively low feeding frequencies were spider predators in agroecosystems (e.g., Whit- also observed in small orb weavers that spin comb 1974, Luczak 1979, Nyffeler 1982, Dean & small delicate nets (LeSar & Unzicker 1978, Sterling 1987); and because oftheir high coloni- Culin & Yeargan 1982, Nyffeler 1982). The de- zation power and insectivorous feeding behav- signs and functions of different types of spider ior, they are of interest to the entomologist and webs are discussed explicitly by Eberhard (1990). ecologist concerned with issues of natural bio- Orb Weaoers. Orb weavers (Araneidae and logical control (compare Turnbull 1973, Riechert Tetragnathidae) spin spiraling sticky webs on & Lockley 1984, Nyffeler & Benz 1987, Sterling and between plants in a wide variety of ffeld et al. 1989). In this article, we present an over- crops and natural habitats. Many orb weavers view ofthe feeding patterns ofthese 10 groups of spin their webs preferentially at the beginning or spider predators. end of the nocturnal period (Foelix f982). Orb weavers wait in a head-down position for prey in the web center (hub) a Materials and Methods or in retreat connected to the hub by a signal line. Alerted by the vibra- There are different methods to evaluate spider tions of an insect struggling in the web, the spi- diets. The prey spectra of spiders can be as- der rushes to its victim; subsequently, the prey is sessed by directly collecting prey organisms or wrapped in silk followed by a venomous bite (in their remains from spider webs (i.e., prey analy- some cases, the prey is first bitten and then ses of web weavers) (Tables l-5), or collecting wrapped) (Foelix 1982). The immobilized prey is spiders with prey in their chelicerae in the ffeld later carried to the hub or retreat where it is (i.e., prey analyses of hunters) (Tables 6-9). Spi- eaten. T etra gnatha lab orio s a }{entz (Tetragnath- der predators (along with their prey) are placed idae), a slender elongate orb weaver (-6 mm in 70Vo ethyl alcohol and later identiffed in the adult length) of yellowish color with a silvery laboratory, using a dissecting microscope (see abdomen, is one of the most abundant spider Nyffeler et al. [987b, 1989] for details). Addi- predators of field crops in the United States tionally, sophisticated methods (e.g., release of (Young & Edwards 1990). With their fragile prey radiolabeled with 32P, ELISA techniques, webs (-lg-15 cm in diameter) oriented at vari- chromatography) are used to detect feeding on ous angles, these spiders trap small soft-bodied insect eggs, tiny aphids, and mites, and other insects predominantly of the orders Diptera and hidden predation activities that may otherwise Homoptera (Table l). Lea{hoppers (Cicadell- be overlooked with visual observation methods idae) represented an essential component (>30Vo (Greenstone 1979, McDaniel & Sterling 1982, of total) in the prey of T. laboröoso in soybean Nyffeler et al. 1990a). The prey spectra pre- ffelds in Illinois and Kentucky (Table l) (LeSar sented in this article (Tables l-9) are all based & Unzicker 1978, Culin & Yeargan 1982). In a on observational data from field studies previ- cotton ffeld in Texas, the prey of this species was ously published in literature (see references in composed largely of aphids (75Vo of total) (Table tables); a large portion of this information had l; Nyffeler et al.
Load more

Recommended publications
  • Pókok Szünbiológiai Kutatása Az Ember Által Befolyásolt Tájban
    AKADÉMIAI DOKTORI ÉRTEKEZÉS Pókok szünbiológiai kutatása az ember által befolyásolt tájban Samu Ferenc, Ph.D. MTA Növényvédelmi Kutatóintézet Budapest 2007 TARTALOM 1 Előszó................................................................................................................... 4 2 Bevezetés ............................................................................................................. 6 2.1 Melyek a pókok ökológiai szerepét meghatározó fő biológiai tulajdonságok? .. 6 2.1.1 Táplálkozás........................................................................................................... 6 2.1.2 A pókfonál használata .......................................................................................... 7 2.1.3 Egyéb fiziológiai tulajdonságok......................................................................... 10 2.1.4 A pókok klasszikus ’sit-and-wait’ ragadozók .................................................... 11 2.2 Pókok a mezőgazdaságban................................................................................. 12 2.2.1 Pókok felhasználása a biológiai védekezésben .................................................. 12 2.2.2 Hazai előzmények a pókok kutatásában............................................................. 16 2.3 Kérdésfelvetés – a kutatások vázlata.................................................................. 18 3 A kutatás módszerei – metodológiai eredmények ......................................... 21 3.1 A kutatás módszerei ..........................................................................................
    [Show full text]
  • Diversidad De Arañas (Arachnida: Araneae) Asociadas Con Viviendas De La Ciudad De México (Zona Metropolitana)
    Revista Mexicana de Biodiversidad 80: 55-69, 2009 Diversidad de arañas (Arachnida: Araneae) asociadas con viviendas de la ciudad de México (Zona Metropolitana) Spider diversity (Arachnida: Araneae) associated with houses in México city (Metropolitan area) César Gabriel Durán-Barrón*, Oscar F. Francke y Tila Ma. Pérez-Ortiz Colección Nacional de Arácnidos (CNAN), Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México. Ciudad Universitaria, Apartado postal 70-153, 04510 México, D. F., México. *Correspondencia: [email protected] Resumen. La ecología urbana es un área de investigación relativamente reciente. Los ecosistemas urbanos son aquellos defi nidos como ambientes dominados por el hombre. Con el proceso de urbanización, insectos y arácnidos silvestres aprovechan los nuevos microhábitats que las viviendas humanas ofrecen. Se revisaron arañas recolectadas dentro de 109 viviendas durante los años de 1985 a 1986, 1996 a 2001 y 2002 a 2003. Se cuantifi caron 1 196 organismos , los cuales se determinaron hasta especie. Se obtuvo una lista de 25 familias, 52 géneros y 63 especies de arañas sinantrópicas. Se utilizaron 3 índices (ocupación, densidad y estacionalidad) y un análisis de intervalos para sustentar la siguiente clasifi cación: accidentales (índice de densidad de 0-0.9), ocasionales (1-2.9), frecuentes (3.0-9.9) y comunes (10 en adelante). Se comparan las faunas de arañas sinantrópicas de 5 países del Nuevo Mundo. Palabras clave: sinantropismo, ecología, urbanización, microhábitats. Abstract. Urban ecology is a relatively new area of research, with urban ecosystems being defi ned as environments dominated by humans. Insects and arachnids are 2 groups that successfully exploit the habitats offered by human habitations.
    [Show full text]
  • Araneae (Spider) Photos
    Araneae (Spider) Photos Araneae (Spiders) About Information on: Spider Photos of Links to WWW Spiders Spiders of North America Relationships Spider Groups Spider Resources -- An Identification Manual About Spiders As in the other arachnid orders, appendage specialization is very important in the evolution of spiders. In spiders the five pairs of appendages of the prosoma (one of the two main body sections) that follow the chelicerae are the pedipalps followed by four pairs of walking legs. The pedipalps are modified to serve as mating organs by mature male spiders. These modifications are often very complicated and differences in their structure are important characteristics used by araneologists in the classification of spiders. Pedipalps in female spiders are structurally much simpler and are used for sensing, manipulating food and sometimes in locomotion. It is relatively easy to tell mature or nearly mature males from female spiders (at least in most groups) by looking at the pedipalps -- in females they look like functional but small legs while in males the ends tend to be enlarged, often greatly so. In young spiders these differences are not evident. There are also appendages on the opisthosoma (the rear body section, the one with no walking legs) the best known being the spinnerets. In the first spiders there were four pairs of spinnerets. Living spiders may have four e.g., (liphistiomorph spiders) or three pairs (e.g., mygalomorph and ecribellate araneomorphs) or three paris of spinnerets and a silk spinning plate called a cribellum (the earliest and many extant araneomorph spiders). Spinnerets' history as appendages is suggested in part by their being projections away from the opisthosoma and the fact that they may retain muscles for movement Much of the success of spiders traces directly to their extensive use of silk and poison.
    [Show full text]
  • Evidence for Spider Community Resilience to Invasion by Non-Native Spiders
    Biological Conservation 98 (2001) 241±249 www.elsevier.com/locate/biocon Evidence for spider community resilience to invasion by non-native spiders Jutta C. Burger a,*, Michael A. Patten b, Thomas R. Prentice a, Richard A. Redak c aDepartment of Entomology, University of California, Riverside, CA 92521, USA bDepartment of Biology, University of California, Riverside, CA 92521, USA cDepartment of Entomology and Center for Conservation Biology, University of California, Riverside, CA 92521, USA Received 14 June 2000; received in revised form 20 June 2000; accepted 17 August 2000 Abstract The negative impacts of non-native species are well documented; however, the ecological outcomes of invasions can vary widely. In order to determine the resilience of local communities to invasion by non-native spiders, we compared spider assemblages from areas with varying numbers of non-native spiders in California coastal sage scrub. Spiders were collected from pitfall traps over 2 years. Productive lowland coastal sites contained both the highest proportion of non-natives and the greatest number of spiders overall. We detected no negative associations between native and non-native spiders and therefore suggest that non-native spiders are not presently impacting local ground-dwelling spiders. Strong positive correlations between abundances of some natives and non-natives may be the result of similar habitat preferences or of facilitation between species. We propose that the eects of non- native species depend on resource availability and site productivity, which, in turn, aect community resilience. Our results support the contention that both invasibility and resilience are higher in diverse, highly linked communities with high resource availability rather than the classical view that species poor communities are more invasible.
    [Show full text]
  • Prey and Periodicity of <I>Pardosa Ramulosa</I> (Mccook) in Alfalfa
    Prey and Periodicity of Pardosa ramulosa1 (McCook) in Alfalfa2 KENNETH V. YEARGAN' Entomology Department, University of California, Davis 95616 ABSTRACT Visual observations of predation by Pardosa ramu/osa (McCook) in alfalfa fields indicate that Hemiptera, Diptera, and Araneae are important prey of this wolf spider. Time-sort pitfall trapping showed that P. ramu/osa and some of its more frequently taken prey species are primarily active during the day. Population samples of the predator and prey species were taken to ascertain seasonal relationships. In contrast to the numerous studies of predaceous alfalfa fields in the summer. Such cracks are often insects in agro-ecosystems, there have been rela- used for escape by P. ramu/osa when disturbed, and Downloaded from https://academic.oup.com/ee/article/4/1/137/2395486 by guest on 27 September 2021 tively few analyses of the role of spiders as preda- make the capture of feeding spiders more difficult. tors. Although spiders are frequently mentioned as Observations were made by moving systematically potential predators of insects, data on their prey and as stealthily as possible through the study area species are scarce. The occasional field observations taking care not to move through the same area of predation by spiders noted in the literature are twice on a given date. By bending or squatting near often mentioned merely as an aside to other work. the ground, it was possible to determine whether Representative of the few extensive field investiga- or not an individual of P. ramu/osa was feeding. tions of spider prey to date, Turnbull (1960) and When a feeding individual was observed, a metal Kajak (1965) studied the prey caught under natural cylinder (6 in.
    [Show full text]
  • Redalyc.Diversidad De Arañas (Arachnida: Araneae) Asociadas
    Revista Mexicana de Biodiversidad ISSN: 1870-3453 [email protected] Universidad Nacional Autónoma de México México Durán-Barrón, César Gabriel; Francke, Oscar F.; Pérez-Ortiz, Tila Ma. Diversidad de arañas (Arachnida: Araneae) asociadas con viviendas de la ciudad de México (Zona Metropolitana) Revista Mexicana de Biodiversidad, vol. 80, núm. 1, 2009, pp. 55-69 Universidad Nacional Autónoma de México Distrito Federal, México Disponible en: http://www.redalyc.org/articulo.oa?id=42511957009 Cómo citar el artículo Número completo Sistema de Información Científica Más información del artículo Red de Revistas Científicas de América Latina, el Caribe, España y Portugal Página de la revista en redalyc.org Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto Revista Mexicana de Biodiversidad 80: 55-69, 2009 Diversidad de arañas (Arachnida: Araneae) asociadas con viviendas de la ciudad de México (Zona Metropolitana) Spider diversity (Arachnida: Araneae) associated with houses in México city (Metropolitan area) César Gabriel Durán-Barrón*, Oscar F. Francke y Tila Ma. Pérez-Ortiz Colección Nacional de Arácnidos (CNAN), Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México. Ciudad Universitaria, Apartado postal 70-153, 04510 México, D. F., México. *Correspondencia: [email protected] Resumen. La ecología urbana es un área de investigación relativamente reciente. Los ecosistemas urbanos son aquellos defi nidos como ambientes dominados por el hombre. Con el proceso de urbanización, insectos y arácnidos silvestres aprovechan los nuevos microhábitats que las viviendas humanas ofrecen. Se revisaron arañas recolectadas dentro de 109 viviendas durante los años de 1985 a 1986, 1996 a 2001 y 2002 a 2003.
    [Show full text]
  • HABITAT USE by the FISHING SPIDER DOLOMEDES TRITON in a NORTHERN Arthropods, Fishes, and Anurans (Gudger 1925, Williams 1979, Zimmerman and Spence 1989)
    Published in Wetlands, Volume 14:239-242. INTRODUCTION The vast freshwater wetlands of the Florida Everglades support a diverse aquatic and semi-aquatic arthropod fauna (Serrao 1980, Gunderson and Loftus 1992). One of the most NOTE conspicuous members of this arthropod fauna is the pisaurid fishing spider Dolomedes triton (Walckenaer). These semi-aquatic, hunting arachnids are voracious predators of other HABITAT USE BY THE FISHING SPIDER DOLOMEDES TRITON IN A NORTHERN arthropods, fishes, and anurans (Gudger 1925, Williams 1979, Zimmerman and Spence 1989). It EVERGLADES WETLAND is plausible that fishing spiders are keystone predators, although there is little agreement concerning the general role that spiders play in structuring either aquatic or terrestrial prey Frank Jordan1,3, Howard L. Jelks2,3, and Wiley M. Kitchens2,3 communities (Turnbull 1973, Foelix 1982, Nyffeler and Benz 1987, Oraze and Grigarick 1989). 1-Department of Zoology Indeed, there are few published studies dealing with any aspect of the biology of spiders living in 2-Department of Wildlife & Range Sciences 3-National Biological Survey natural wetland systems. Clearly, quantitative abundance and distribution data are needed to Florida Cooperative Fish & Wildlife Research Unit University of Florida increase our understanding of the ecology of fishing spiders in freshwater wetlands. 117 Newins-Ziegler Hall Gainesville, FL 32611 In this paper, we provide basic habitat use information about the fishing spider D. triton in the Arthur R. Marshall Loxahatchee National Wildlife Refuge, a northern Everglades wetland system. Specifically, patterns of differential habitat use and seasonal variation in abundance Abstract: We investigated patterns of habitat use by adult fishing spiders Dolomedes triton in a were examined during an 18-month period.
    [Show full text]
  • Spider and Beetle Communities Across Urban Greenspaces in Cleveland, Ohio
    Spider and Beetle Communities across Urban Greenspaces in Cleveland, Ohio: Distributions, Patterns, and Processes Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Yvan A. Delgado de la flor, B.S. Graduate Program in Entomology The Ohio State University 2020 Dissertation Committee: Mary M. Gardiner, Adviser Luis Cañas Robert J. Gates Andrew P. Michel William O.C. Symondson Copyright by Yvan A. Delgado de la flor 2020 Abstract Urban areas are often considered adverse environments for wildlife communities given that the colonization and establishment of local species pools are disrupted by biotic and abiotic changes at different spatial scales such as the introduction of invasive species, periodic mowing, and changes in soil and air quality. Although the number of people residing in cities has increased in the last century, over 300 cities worldwide have shrunk due to prolonged economic decline and population loss, resulting in thousands of newly available greenspaces scattered throughout cities. Consequently, interest in urban greenspaces as sites for conservation has grown considerably, raising questions about the ability of these habitats to support wildlife. As novel ecosystems, urban areas represent a set of new challenges for local species pools, yet the mechanisms driving community assembly processes within cities is a major knowledge gap. My work focused on identifying species distributions, patterns, and processes leading to the successful establishment arthropods in cities. For this, I chose to work with beetle and spider assemblages as they are considered biological indicators of environmental changes at small and large spatial scales and are taxonomically and functionally diverse predatory groups.
    [Show full text]
  • Predation Behavior of Spiders (Arachnida: Araneae) in Massachusetts Cranberry Bog Ecosystems
    University of Massachusetts Amherst ScholarWorks@UMass Amherst Masters Theses 1911 - February 2014 1995 Predation behavior of spiders (Arachnida: Araneae) in Massachusetts cranberry bog ecosystems. Carolyn J. Bardwell University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/theses Bardwell, Carolyn J., "Predation behavior of spiders (Arachnida: Araneae) in Massachusetts cranberry bog ecosystems." (1995). Masters Theses 1911 - February 2014. 3066. Retrieved from https://scholarworks.umass.edu/theses/3066 This thesis is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Masters Theses 1911 - February 2014 by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. PREDATION BEHAVIOR OF SPIDERS (ARACHNIDA: ARANEAE) IN MASSACHUSETTS CRANBERRY BOG ECOSYSTEMS A Thesis Presented by CAROLYN J. BARDWELL Submitted to the Graduate School of the University of Massachusetts Amherst in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1995 Department of Entomology PREDATION BEHAVIOR OF SPIDERS (ARACHNIDA: ARANEAE) IN MASSACHUSETTS CRANBERRY BOG ECOSYSTEMS A Thesis Presented by CAROLYN J. BARDWELL Approved as to style and content by: Roy G/Van Driesche, Member Department of Entomology DEDICATION This work is dedicated to my parents, Barbara & Frederick, who have been supportive throughout all of my “educational pursuits”, Vincent, who always encouraged and believed in me, and Jessica, whose energy and dedication are behind every page. ACKNOWLEDGMENTS I am very grateful to the many people who have contributed their time, effort, and friendship during the years I have worked toward the completion of this thesis.
    [Show full text]
  • Araneida) in a N Ontario Meadow
    Dondale, C . D . 1977 . Life histories and distribution patterns of hunting spiders (Araneida) in a n Ontario meadow . J . Arachnol . 4 :73-93 . LIFE HISTORIES AND DISTRIBUTION PATTERNS OF HUNTIN G SPIDERS (ARANEIDA) IN AN ONTARIO MEADO W C. D . Dondale Biosystematics Research Institut e Research Branch, Agriculture Canad a Ottawa, Ontario K1A OC 6 ABSTRAC T Life histories and distribution patterns were reconstructed from random vacuum samples o f coexistent populations of nine species of hunting spiders in an Ontario meadow . The populations o f Pardosa saxatilis (Hentz), Pirata minutus Emerton, Schizocosa avida (Walckenaer), S. heasmani Dondale, and S. crassipalpis (Emerton) had annual life histories, and matured, mated, and oviposite d in the spring or early summer. Xysticus pellax (O . Pickard-Cambridge) and X. gulosus Keyserling were also annual, but matured and mated in late summer or early autumn, and oviposited the followin g spring . X. discursans Keyserling was biennial, and matured and reproduced in the spring . Lycosa frondicola Emerton was also biennial, but matured in late summer and reproduced the following spring . Most of the nine species were more densely represented in the lower, moister part of th e meadow, whereas S. heasmani, individuals of which are very similar in anatomy to those of S . avida , was more densely represented on the higher, dryer part, and the adults of L. frondicola kept largely t o the edge of the meadow nearest the forest . INTRODUCTIO N Ideally, the life history of an animal species is a summary of vital events from birth t o death in the average generation .
    [Show full text]
  • DIURNAL Activity of ALOPECOSA PULVERULENTA (CLERCK 1757) (LYCOSIDAE, ARANEAE)
    Commun. Fac. Sci. Univ. Ank. Serics C V. 13. pp. 13-20 (1995) DIURNAL activity OF ALOPECOSA PULVERULENTA (CLERCK 1757) (LYCOSIDAE, ARANEAE) ABDULLAH BAYRAM Department of Biology^ Faculty of Art and Science, University of Yüzüncü Yıl, Van, Turkey Receİved Dec. 28, 1994; Revised Feb. 7, 1995; Accepted March 1, 1995 ABSTRACT In this study, diel activity of Alopecosa pulverulenta (Clerck, 1757) vvas established using the time-sporting pitfall trap in a grassland located between crop fields in northeast England. In spide of capture of A. pulverulenta during day-time and night, ınost were caught during the light periods. The ma)e and female specimens wcre more active in the afternoon and morning periods, respectively, and fonowed by the sunset period. 73.4 % of the adults were collected only in the afternoon and morning periods. Littie activity was recorded during the evening, midnight and sunrise periods. The males were caught ınore than the feraales during the study (1 j 0.73 lycosid per hour per collection). Like adults the immatures were caught in all periods. Howe- ver they were more active in the afternoon periods. INTRODUCTION Spiders are among the most abundant arthropod predators. For this reason, spiders in agroecosystem have been the subject of numerous studies (Nyffeler 1982, 1987, 1988; Whitcomb et al. 1963, Yeargan et al. 1974, 1975; Bayram et al. 1993 a,b; Bayram 1993, 1994). Despite the prevalence of noııweb-building spidcrs, such as the lycosids, in some field crops (Dean et al. 1982, Whitcomb et al. 1963, Yeargan et al. 1974,*5 1975), studies attempting to determine the prey items and frequency of prey taken are relatively uncommon.
    [Show full text]
  • A Comparison of the Composition of Silk Proteins Produced by Spiders and Insects
    International Journal of Biological Macromolecules 24 (1999) 109–118 A comparison of the composition of silk proteins produced by spiders and insects Catherine L. Craig a,*, Michael Hsu b,1, David Kaplan c, N.E. Pierce a a Museum of Comparati6e Zoology, Har6ard Uni6ersity, 26 Oxford Street, Cambridge, MA 02138, USA b Currier House, Har6ard Uni6ersity, Cambridge, MA 02138, USA c Tufts Uni6ersity, Department of Chemical Engineering & Biotechnology Center, Medford, MA 02155, USA Abstract Proteins that are highly expressed and composed of amino acids that are costly to synthesize are likely to place a greater drain on an organism’s energy resources than proteins that are composed of ingested amino acids or ones that are metabolically simple to produce. Silks are highly expressed proteins produced by all spiders and many insects. We compared the metabolic costs of silks spun by arthropods by calculating the amount of ATP required to produce their component amino acids. Although a definitive conclusion requires detailed information on the dietary pools of amino acids available to arthropods, on the basis of the central metabolic pathways, silks spun by herbivorous, Lepidoptera larvae require significantly less ATP to synthesize than the dragline silks spun by predatory spiders. While not enough data are available to draw a statistically based conclusion, comparison of homologous silks across ancestral and derived taxa of the Araneoidea seems to suggest an evolutionary trend towards reduced silk costs. However, comparison of the synthetic costs of dragline silks across all araneomorph spiders suggests a complicated evolutionary pattern that cannot be attributed to phylogenetic position alone. We propose that the diverse silk-producing systems of the araneoid spiders (including three types of protein glues and three types of silk fibroin), evolved through intra-organ competition and that taxon-specific differences in the composition of silks drawn from homologous glands may reflect limited or fluctuating amino acid availability.
    [Show full text]