Uloboridae

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William G Eberhard - One of the best experts on this subject based on the ideXlab platform.

  • factores selectivos que afectan la tendencia a agruparse en la arana colonial philoponella semiplumosa araneae Uloboridae
    Revista De Biologia Tropical, 2016
    Co-Authors: E J Lahmann, William G Eberhard
    Abstract:

    The spider Philoponella semiplumosa in NW Costa Rica lives both alone and in colonial webs, with the relative numbers of solitary and colonial individuals differing in different habitats. Interactions between colonial individuals when prey fell in the web were sometimes competitive with larger spiders consistenly dominating and sometimes altruistic, with larger ones allowing others to enter their webs and capture prey there. Solitary individuals constructed stabilimenta more frequently, and may thus be subject to greater predation than colonial spiders. Colonial spiders of large sizes spun smaller webs than equal-sized solitary individuals. Nevertheless, the rates of prey capture were the same for solitary and colonial individuals in one habitat, suggesting that colonial life may increase predatory efficiency. Migration rates into and away from colonies were high (averaging from 40-80% per day), but the tendencies for spiders of certain sizes to clump non-randomly suggest that members of colonies may tend to be relatively highly related genetically. The balance of selective factors favoring solitary or colonial life in this species is probably complex.

  • the effect of regurgitated digestive fluid on the spider s own legs in philoponella vicina araneae Uloboridae
    Journal of Arachnology, 2012
    Co-Authors: Carolina Esquivel, William G Eberhard, Ignacio Escalante
    Abstract:

    Abstract Philoponella vicina O. Pickard-Cambridge 1899 rests on its orb web in a cryptic posture with its legs folded against its body. While feeding, the spider coats the entire prey with digestive fluid and changes its posture, spreading its anterior legs wide. We tested whether this change in leg position may function to protect against damage to its legs from its own digestive fluid. When we touched detached legs I with prey packages wetted with digestive fluid, more setae fell from the legs than when we applied tap water in a similar manner. In addition, intersegmental membranes were damaged by digestive fluid, but not by water. This and other uloborids may thus break their cryptic postures while feeding in order to avoid damage from their own digestive enzymes.

  • stabilimenta on the webs of uloborus diversus araneae Uloboridae and other spiders
    Journal of Zoology, 2010
    Co-Authors: William G Eberhard
    Abstract:

    Uloborus diversus places extra silk (“stabilimenta”) near the hubs of its webs, preferentially on short radii ending near anchor threads. Spiders probably distinguish these radii from others by their relatively low extensibility. The stabilimentum probably functions as a camouflage device, and the orientation of the stabilimentum lines probably aids disturbed spiders in making quick exits from webs. Turning responses at radius-frame junctions during these exits are influenced by thread angles at the junctions (and possibly by other factors), and also enable disturbed spiders to reach hiding places quickly. The available data on other stabilimentum-building spiders suggests that they also use stabilimenta to provide defence against visually-hunting predators.

  • the web of uloborus diversus araneae Uloboridae
    Journal of Zoology, 2009
    Co-Authors: William G Eberhard
    Abstract:

    The construction behaviour, design, and function of the orb webs of Uloboi sus are discussed in detail. The major phases and many of the details of construction behaviour are similar to the orb construction behaviour of some araneids. Frame threads are laid in a relatively fixed order, and are often made with a single set of movements repeated over and over. Radii and hub threads are laid after most of the frame threads are in place. Radii are connected to each other by the hub thread, and are actually continuous with it. A temporary spiral of non-sticky silk is laid starting at the hub and ending near the edge of the web. Tertiary radii are laid during construction of the temporary spiral and are continuous with it. Sticky spiral construction behaviour varies slightly with the site in the web but is very similar to that of Araneus diadematus. The behaviour of one leg following another in both time and space is described for the first time in spiders. Three types of web repair are described, one for the first time. The paths taken by spiders during radius construction (deduced from study of the hubs of completed webs), and the bending of radii by hub and temporary spiral threads suggest that all radii in a U. diversus web are not under equal tensions. The lack of secondary frame threads results in unequal stressing of some frame threads. Considerations of the structural properties of an orb imply these inequalities in tension probably lower web stability. The correlation between radius length and inter-radius angle, the sites of tertiary radii, and the bending of radii by the temporary spiral all indicate there has been selection to keep the distance between adjacent radii below some maximum value. Possible reasons for this are discussed. The outer loop of sticky spiral differs from those of many araneids in several respects, and probable functions of some of its characteristics are discussed. The site of the outer loop of sticky spiral is influenced by the site of the outer loop of temporary spiral. The spacing between loops of sticky spiral varies with radius length and with distance from the hub, but the functions of these variations are not clear. Changes in the average spacing between loops of sticky spirals on successive webs of individuals and in repair zones constructed the day of web construction imply that the spacing between loops of sticky spiral on a given web is probably influenced by the amount of silk available in the spider. The sticky spiral of U. diversus differs from those of all known araneids in not being attached to each radius it crosses, but the function of this characteristic is not clear. Many of the patterns in the web imply the spider adjusts its construction behaviour on the basis of cues received from its web. It appears that the spider can differentiate between sticky and non-sticky silk, and can sense the angles between radii while at the hub, the distance between radii and the distance to a frame thread during temporary spiral construction, the lengths of radii during sticky spiral construction, and probably the area to be covered by sticky silk and the amount of sticky silk available. There is evidence that adjustments are made on the basis of additional information, and possible sources of this information are discussed. Although the webs of U. diversus differ from the known webs of araneids in several respects, they do not give clear evidence that the family Uloboridae should be separated far from the family Araneidae. In general, there is more variation in web types within the Araneidae than between those of U. diversus and the araneids.

  • stabilimenta of philoponella vicina araneae Uloboridae and gasteracantha cancriformis araneae araneidae evidence against a prey attractant function
    Biotropica, 2007
    Co-Authors: William G Eberhard
    Abstract:

    Both the uloborid Philoponella vicina and the araneid Gasteracantha cancriformis spiders sometimes placed silk stabilimenta on non-orb “resting webs” that consisted of only one or a few lines. These webs completely lacked sticky silk, so their stabilimenta could not function to attract prey. Some non-orbs were built by spiders when their orb webs are damaged. These observations contradict the prey attraction camouflage hypothesis for stabilimentum function, but are compatible with the spider camouflage and web advertisement to avoid web destruction hypotheses.

Brent D. Opell - One of the best experts on this subject based on the ideXlab platform.

  • a review of the genus tangaroa araneae Uloboridae
    2016
    Co-Authors: Brent D. Opell
    Abstract:

    Characteristics of the genus Tangaroa are reviewed and the new species, T beattyi, is described and compared with T. dissimilis (Berland) and T. tahitiensis (Berland). Cladistic analysis shows the first two species to be most closely related. The tetraspermathecate female genitalia of this genus show no evidence of fertilization ducts and appear to represent a transition state between haplogyne and entelegyne grades of organization.

  • molecular phylogenetic evidence for the parallel evolution of rock ecomorphs in the new zealand orb weaving spider waitkera waitakerensis family Uloboridae
    Journal of Arachnology, 2006
    Co-Authors: Brent D. Opell
    Abstract:

    The genus Waitkera is the only New Zealand representative of the family Uloboridae and is known from a single species, Waitkera waitakerensis. This species is found in forests of the North Island, where it constructs orb-webs on understory vegetation. Rock outcrops in the Northland region support populations of W. waitkerensis comprised of larger individuals than those found elsewhere on the island, including those in surrounding forests. Parsimony analyses of DNA sequences from the mitochon- drial NADH dehydrogenase subunit ND1, using Siratoba refernes, another basal uloborid, as an outgroup, did not delineate these rock-dwelling populations as a monophyletic lineage that could be regarded as a distinct species. A TCS analysis leads to the same conclusion, suggesting that rock-dwelling populations represent independently evolved ecotypes. Northland populations of W. waitakerensis are phylogenetically basal; indicating that the species' range contracted northward during the Pleistocene and recolonized the remainder of the North Island.

  • egg sac recognition by female miagrammopes animotus araneae Uloboridae
    Journal of Arachnology, 2001
    Co-Authors: Brent D. Opell
    Abstract:

    After producing a cylindrical egg sac, a female Miagrammopes animotusholds it until spiderlings emerge and disperse. When sacs were taken from females, these females exhibited a putative searching behavior and, upon contacting either their sacs or those of conspecifics, exhibited a putative recognition behavior. These responses would cause a female to search for and reclaim her sac if it were temporarily abandoned during feeding or web construction. Females with sacs did not respond positively to sacs from which spiderlings had emerged. Females that did not have sacs did not respond positively to viable sacs. Females separated from their sacs for increasing time periods exhibited a decline in positive responses to their sacs. Thus, contact with the sac appears necessary to maintain an affinity for the sac during the development of spiderlings.

  • cribellum and calamistrum ontogeny in the spider family Uloboridae linking functionally related but separate silk spinning features
    Journal of Arachnology, 2001
    Co-Authors: Brent D. Opell
    Abstract:

    Abstract The fourth metatarsus of cribellate spiders bears a setal comb, the calamistrum, that sweeps over the cribellum, drawing fibrils from its spigots and helping to combine these with the capture thread's supporting fibers. In four uloborid species (Hyptiotes cavatus, Miagrammopes animotus, Octonoba sinensis, Uloborus glomosus), calamistrum length and cribellum width have similar developmental trajectories, despite being borne on different regions of the body. In contrast, developmental rates of metatarsus IV and its calamistrum differ within species and vary independently among species. Thus, the growth rates of metatarsus IV and the calamistrum are not coupled, freeing calamistrum length to track cribellum width and metatarsus IV length to respond to changes in such features as combing behavior and abdomen dimensions.

  • ontogenetic changes in cribellum spigot number and cribellar prey capture thread stickiness in the spider family Uloboridae
    Journal of Morphology, 1995
    Co-Authors: Brent D. Opell
    Abstract:

    Uloborids produce dry cribellar prey capture thread whose surface is formed of thousands of fine, looped fibrils. These fibrils are spun from spigots on an oval spinning plate termed the cribellum and handled by a setal comb on the fourth leg termed the calamistrum. Ontogenetic studies of the triangle-web species Hyptiotes cavatus and the simple-web species Miagrammopes animotus show that increases in the number of cribellar spinning spigots are associated with increases in the stickiness of cribellar threads. For H. cavatus this relationship is similar to that determined by a previous interspecific comparison. Relative to cribellum spigot number, M. antimotus produces stickier threads than does H. cavatus. Differences in the features of these species' cribellar fibrils do not explain difference in thread stickiness. Cribellar threads produced by M. animotus have shorter, wider puffs than those produced by H. cavatus and, consequently, achieve a greater contact surface area per mm of length than do threads produced by H. cavatus. The more closely spaced cribellum spigots of M. animotus maximize the number of fibrils that contact a surface. Miagrammopes animotus also has a longer calamistrum and more closely spaced calamistrum setae than does H. cavatus. This demonstrates how small differences in spinning anatomy and behavior can fine-tune the physical characteristics of cribellar threads in ways that maximize their stickiness. © 1995 Wiley-Liss, Inc.

Gustavo Hormiga - One of the best experts on this subject based on the ideXlab platform.

  • phylogeny of extant nephilid orb weaving spiders araneae nephilidae testing morphological and ethological homologies
    Cladistics, 2008
    Co-Authors: Jonathan A Coddington, Matjaž Kuntner, Gustavo Hormiga
    Abstract:

    The Pantropical spider clade Nephilidae is famous for its extreme sexual size dimorphism, for constructing the largest orb-webs known, and for unusual sexual behaviors, which include emasculation and extreme polygamy. We synthesize the available data for the genera Nephila, Nephilengys, Herennia and Clitaetra to produce the first species level phylogeny of the family. We score 231 characters (197 morphological, 34 behavioral) for 61 taxa: 32 of the 37 known nephilid species plus two Phonognatha and one Deliochus species, 10 tetragnathid outgroups, nine araneids, and one genus each of Nesticidae, Theridiidae, Theridiosomatidae, Linyphiidae, Pimoidae, Uloboridae and Deinopidae. Four most parsimonious trees resulted, among which successive weighting preferred one ingroup topology. Neither an analysis of an alternative data set based on different morphological interpretations, nor separate analyses of morphology and behavior are superior to the total evidence analysis, which we therefore propose as the working hypothesis of nephilid relationships, and the basis for classification. Ingroup generic relationships are (Clitaetra (Herennia (Nephila, Nephilengys))). Deliochus and Phonognatha group with Araneidae rather than Nephilidae. Nephilidae is sister to all other araneoids (contra most recent literature). Ethological data, although difficult to obtain and thus frequently missing for rare taxa, are phylogenetically informative. We explore the evolution of selected morphological and behavioral characters, discuss and redefine the homology of palpal sclerites, disprove semientelegyny in spiders, trace the newly interpreted evolution of the orb web, and show that nephilid genital morphologies coevolve with sexual behaviors and extreme sexual size dimorphism. Phylogenetic interpretations of behavior suggest new insights into spider biology and avenues for future research. © The Willi Hennig Society 2007.

  • phylogeny of the orb web building spiders araneae orbiculariae deinopoidea araneoidea
    Zoological Journal of the Linnean Society, 1998
    Co-Authors: Charles E Griswold, Jonathan A Coddington, Gustavo Hormiga, Nikolaj Scharff
    Abstract:

    Abstract This phylogenetic analysis of 31 exemplar taxa treats the 12 families of Araneoidea (Anapidae, Araneidae, Cyatholipidae, Linyphiidae, Mysmenidae, Nesticidae, Pimoidae, Symphytognathidae, Synotaxidae, Tetragnathidae, Theridiidae, and Theridiosomatidae). The data set comprises 93 characters: 23 from male genitalia, 3 from female genitalia, 18 from cephalothorax morphology, 6 from abdomen morphology, 14 from limb morphology, 15 from the spinnerets, and 14 from web architecture and other behaviour. Criteria for tree choice were minimum length parsimony and parsimony under implied weights. The outgroup for Araneoidea is Deinopoidea (Deinopidae and Uloboridae). The preferred shortest tree specifies the relationships ((Uloboridae, Deinopidae) (Araneidae (Tetragnathidae ((Theridiosomatidae (Mysmenidae (Symphytognathidae, Anapidae))) ((Linyphiidae, Pimoidae) ((Theridiidae, Nesticidae) (Cyatholipidae, Synotaxidae))))))). The monophyly of Tetragnathidae (including metines and nephilines), the symphytognathoids, theridiid-nesticid lineage, and Synotaxidae are confirmed. Cyatholipidae are sister to Synotaxidae, not closely related to either the Araneidae or Linyphiidae, as previously suggested. Four new clades are proposed: the cyatholipoids (Cyatholipidae plus Synotaxidae), the «spineless femur clade» (theridioid lineage plus cyatholipoids), the «araneoid sheet web builders» (linyphioids plus the spineless femur clade), and the «reduced piriform clade» (symphytognathoids plus araneoid sheet web builders). The results imply a coherent scenario for web evolution in which the monophyletic orb gives rise to the monophyletic araneoid sheet, which in turn gives rise to the gumfoot web of the theridiid-nesticid lineage. While the spinning complement of single pairs of glands does not change much over the evolution of the group, multiple sets of glands are dramatically reduced in number, implying that derived araneoids are incapable of spinning many silk fibers at the same time.

  • Phylogeny of the orb-web building spiders (Araneae, Orbiculariae
    1998
    Co-Authors: Charles E Griswold, Jonathan A Coddington, Gustavo Hormiga, Nikolaj Scharff
    Abstract:

    data set comprises 93 characters: 23 from male genitalia, 3 from female genitalia, 18 from cephalothorax morphology, 6 from abdomen morphology, 14 from limb morphology, 15 from the spinnerets, and 14 from web architecture and other behaviour. Criteria for tree choice were minimum length parsimony and parsimony under implied weights. The outgroup for Araneoidea is Deinopoidea (Deinopidae and Uloboridae). The preferred shortest tree specifies the relationships ((Uloboridae, Deinopidae) (Araneidae (Tetragnathidae ((Theri-diosomatidae (Mysmenidae (Symphytognathidae, Anapidae))) ((Linyphiidae, Pimoidae) ((Theridiidae, Nesticidae) (Cyatholipidae, Synotaxidae))))))). The monophyly of Tetragnathidae (including metines and nephilines), the symphytognathoids, theridiid-nesticid lineage, and Synotaxidae are confirmed. Cyatholipidae are sister to Synotaxidae, not closely related to either the Araneidae or Linyphiidae, as previously suggested. Four new clades are proposed: the cyatholipoids (Cyatholipidae plus Synotaxidae), the ‘spineless femur clade ’ (theridioid lineage plus cyatholipoids), the ‘araneoid sheet web builders ’ (linyphioids plus the spineless femur clade), and the ‘reduced piriform clade ’ (symphytognathoids plus araneoid sheet web builders). The results imply a coherent scenario for web evolution in which the monophyleti

Nikolaj Scharff - One of the best experts on this subject based on the ideXlab platform.

  • phylogeny of the orb web building spiders araneae orbiculariae deinopoidea araneoidea
    Zoological Journal of the Linnean Society, 1998
    Co-Authors: Charles E Griswold, Jonathan A Coddington, Gustavo Hormiga, Nikolaj Scharff
    Abstract:

    Abstract This phylogenetic analysis of 31 exemplar taxa treats the 12 families of Araneoidea (Anapidae, Araneidae, Cyatholipidae, Linyphiidae, Mysmenidae, Nesticidae, Pimoidae, Symphytognathidae, Synotaxidae, Tetragnathidae, Theridiidae, and Theridiosomatidae). The data set comprises 93 characters: 23 from male genitalia, 3 from female genitalia, 18 from cephalothorax morphology, 6 from abdomen morphology, 14 from limb morphology, 15 from the spinnerets, and 14 from web architecture and other behaviour. Criteria for tree choice were minimum length parsimony and parsimony under implied weights. The outgroup for Araneoidea is Deinopoidea (Deinopidae and Uloboridae). The preferred shortest tree specifies the relationships ((Uloboridae, Deinopidae) (Araneidae (Tetragnathidae ((Theridiosomatidae (Mysmenidae (Symphytognathidae, Anapidae))) ((Linyphiidae, Pimoidae) ((Theridiidae, Nesticidae) (Cyatholipidae, Synotaxidae))))))). The monophyly of Tetragnathidae (including metines and nephilines), the symphytognathoids, theridiid-nesticid lineage, and Synotaxidae are confirmed. Cyatholipidae are sister to Synotaxidae, not closely related to either the Araneidae or Linyphiidae, as previously suggested. Four new clades are proposed: the cyatholipoids (Cyatholipidae plus Synotaxidae), the «spineless femur clade» (theridioid lineage plus cyatholipoids), the «araneoid sheet web builders» (linyphioids plus the spineless femur clade), and the «reduced piriform clade» (symphytognathoids plus araneoid sheet web builders). The results imply a coherent scenario for web evolution in which the monophyletic orb gives rise to the monophyletic araneoid sheet, which in turn gives rise to the gumfoot web of the theridiid-nesticid lineage. While the spinning complement of single pairs of glands does not change much over the evolution of the group, multiple sets of glands are dramatically reduced in number, implying that derived araneoids are incapable of spinning many silk fibers at the same time.

  • Phylogeny of the orb-web building spiders (Araneae, Orbiculariae
    1998
    Co-Authors: Charles E Griswold, Jonathan A Coddington, Gustavo Hormiga, Nikolaj Scharff
    Abstract:

    data set comprises 93 characters: 23 from male genitalia, 3 from female genitalia, 18 from cephalothorax morphology, 6 from abdomen morphology, 14 from limb morphology, 15 from the spinnerets, and 14 from web architecture and other behaviour. Criteria for tree choice were minimum length parsimony and parsimony under implied weights. The outgroup for Araneoidea is Deinopoidea (Deinopidae and Uloboridae). The preferred shortest tree specifies the relationships ((Uloboridae, Deinopidae) (Araneidae (Tetragnathidae ((Theri-diosomatidae (Mysmenidae (Symphytognathidae, Anapidae))) ((Linyphiidae, Pimoidae) ((Theridiidae, Nesticidae) (Cyatholipidae, Synotaxidae))))))). The monophyly of Tetragnathidae (including metines and nephilines), the symphytognathoids, theridiid-nesticid lineage, and Synotaxidae are confirmed. Cyatholipidae are sister to Synotaxidae, not closely related to either the Araneidae or Linyphiidae, as previously suggested. Four new clades are proposed: the cyatholipoids (Cyatholipidae plus Synotaxidae), the ‘spineless femur clade ’ (theridioid lineage plus cyatholipoids), the ‘araneoid sheet web builders ’ (linyphioids plus the spineless femur clade), and the ‘reduced piriform clade ’ (symphytognathoids plus araneoid sheet web builders). The results imply a coherent scenario for web evolution in which the monophyleti

Werner Baumgartner - One of the best experts on this subject based on the ideXlab platform.

  • morphological adaptation of the calamistrum to the cribellate spinning process in deinopoidae Uloboridae deinopidae
    Royal Society Open Science, 2016
    Co-Authors: Annachristin Joel, Ingo Scholz, Linda Orth, Peter Kappel, Werner Baumgartner
    Abstract:

    Spiders are famous for their silk with fascinating mechanical properties. However, some can further produce, process and handle nano fibres, which are used as capture threads. These ‘cribellate spi...

  • morphological adaptation of the calamistrum to the cribellate spinning process in deinopoidae Uloboridae deinopidae
    Royal Society Open Science, 2016
    Co-Authors: Annachristin Joel, Ingo Scholz, Linda Orth, Peter Kappel, Werner Baumgartner
    Abstract:

    Spiders are famous for their silk with fascinating mechanical properties. However, some can further produce, process and handle nano fibres, which are used as capture threads. These 'cribellate spiders' bear a specialized setae comb on their metatarsus (calamistrum), which modifies cribellate nano fibres to assemble a puffy structure within the capture thread. Among different species, the calamistrum morphology can differ remarkably. Although a model of thread production has been established for Uloborus plumipes, it is not resolved if/how different shaped calamistra influence the production process. We were able to transfer the model without restrictions to spiders with different shaped calamistra. Fibres are not locked between setae but are passing across a rather smooth surface-like area on the calamistrum. This area can be relocated, explaining the first morphological difference between calamistra, without changing the influence of the calamistrum on fibres. By performing an elongated leg movement, contact between fibres and calamistrum could be adjusted after finishing thread production. This movement has to bring the thread in contact with the second morphological peculiarity: cribellate teeth. We suggest these teeth are used to handle the thread independently of the spinnerets, a feature only necessary for spiders, which do not move during web construction.