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Abstract Silk is an excellent natural fiber, which has been widely used in versatile fields. Silk spinning is a complex process involving the larval spinneret. The spinneret is essential for silk spinning, but the sectional morphology of the spinneret that determines the silk monofilament, the muscular activities around the silk press as well as the relationships between the spinneret and the properties of the resulting silk remain poorly understood. We studied these factors by dissecting the spinneret and analyzing silk from different Bombyx mori strains. The sectional morphology of silk monofilament was found to be largely determined by the spinneret, especially by the silk press. Moreover, contractile activity of the muscles around the silk press is high, and the contraction frequency of the muscles was estimated to range from 11.42 to 50 HZ. A comparison of the fibroin filaments before they entered the common tube indicated that the spinneret determines both silk shape and silk size. This study provides insight into the silk spinning process, which may help develop bionic spinning in further studies and also provides a rationale to study the effect of the spinneret on silk fineness at the molecular level. [ABSTRACT FROM AUTHOR]

Grooved nerve guide conduits (NGCs) have been effective in the clinical treatment of peripheral nerve injury. They are generally fabricated from a micro-structured spinneret using a spinning process, which easily can cause a variety of pores and morphological deviation. The topography of internal grooves as well as the porosity can greatly influence the therapeutic effect. Traditional optical or scanning electron microscopy (SEM) methods can be used to image the grooves; however, these methods are destructive and require slicing NGCs to prepare specimens suitable for imaging. Moreover, lengthy experiments and large batches of NGCs are required to ensure reliable results from both in vitro experiments and clinical studies. In this paper, a non-destructive method for evaluating the grooves and porosity of NGCs is proposed using ultrasonic imaging combined with rotary scanning and an image analysis algorithm. Two ultrasonic methods were used: a 25-MHz point-focus ultrasonic transducer applied to observe axial cross sections of the conduits and a 100-MHz point-focus ultrasonic transducer to detect large pores caused by defects. Furthermore, a theoretical algorithm for detecting the local porosity of a conduit based on density is proposed. Herein, the proposed acoustic method and traditional optical methods are evaluated and compared. A parameter representing the specific surface area of the internal grooves is introduced and computed for both the optical and acoustic methods, and the relative errors of the computed parameter values for three different NGCs were 7.0%, 7.9%, and 15.3%. The detected location and shape of pores were consistent between the acoustic and optical methods, and greater porosity was observed in the middle of the conduit wall. In this paper, the results of the acoustic and optical methods are presented and the errors relating to the acoustic factors, device characteristics, and image processing method are further analyzed. [ABSTRACT FROM AUTHOR]

Composite membranes are the work horse of reverse osmosis and nanofiltration processes. Recently, we presented a chemistry in a spinneret methodology. The membrane forming polymer reacts with a monomer/cross-linker added to the bore fluid resulting into a composite membrane made by a single process step. Here, the reaction of a cross-linking agent and an amine reactant superimposes the conventional phase inversion of an inert polymer during dry-jet wet spinning. While the inert polymer precipitates as porous support structure, the cross-linking reaction forms the desired dense separation layer on the lumen-side. Such membranes have nanofiltration properties and can be backwashed extensively. Two different interfacial condensation reactions showcase the versatility of this method and the used polyethyleneimine determines the salt retention hierarchy given by its positive charge. This work suggests that the many established membrane postmodifications known in the field could be considered for this “chemistry in a spinneret” inline modification. [ABSTRACT FROM AUTHOR]

Nerve conduits with topographical guidance have been recognized as the efficient repair of damaged peripheral nerves. In this study, polymeric hollow fiber membranes (HFMs) with grooved inner surface have been fabricated from a microstructured spinneret using a dry-jet wet spinning process for nerve regeneration studies. The effectiveness of HFM inner grooves has been demonstrated during an in vitro study of chick forebrain neuron outgrowth. It is of great importance that the groove geometry can be controllable to meet various needs in promoting nerve regeneration performance. While the overall groove geometry is determined by the spinneret design, fabrication conditions are also indispensable in fine-tuning the final groove geometry such as the groove height and width on the order of 10 µm or less. It is found that the bore fluid flow rate can be utilized to effectively adjust the resulting groove height by at most 52% and groove width by at most 61%, respectively, without modifying the spinneret geometry. This enables a new approach to fabricate different grooved HFMs using the same spinneret. By comparing to the influences of bore fluid flow rate, the dope fluid flow rate is less effective in regulating the groove height and width when using the same microstructured spinneret. Both bore and dope fluid flow rates should be carefully selected for fine groove width tuning. [ABSTRACT FROM AUTHOR]

Tetranychus turkestani is a serious pest of cotton, corn, vegetables, fruit trees and forests in Xinjiang. All life stages of T. turkestani were observed using both light and scanning electron microscope. The egg is smooth and spherical. The eupathidial spinnerets of larva and protonymph are different from that of the deutonymph and adult in shape. The spinneret of adult female is obviously thicker and larger than that in male. The palpfemoral seta of adult male is a short, stout, spine-like process. T. turkestani has fourteen pairs of dorsal setae. The number of ventral setae increases regularly in number in each molt. The leg chaetotaxy has a great change from larva to deutonymph. [ABSTRACT FROM AUTHOR]

This paper reports the first study on centrifugal spinning of PHBV fibres. Fibres were spun from solution using a range of polymer concentrations, spin speeds and spinneret to collector distances. A PHBV polymer concentration of 25% w/v spun at 9000 r min − 1 produced the highest quality fibres, with fibre diameters predominantly in the 0.5–3 μm range. The rate at which fibre could be produced at the 9000 r min − 1 spin speed and with a spinneret to collector distance of 39.2 cm was equivalent to 11 km of fibre per minute per needle. Average fibre strengths of 3 MPa were achieved, together with average moduli of 100 MPa, indicating that the fibres had higher strength but lower stiffness than electrospun PHBV. The productivity and mechanical properties achieved, together with the excellent biocompatibility of PHBV, means that these fibres have potential for application in a range of biomedical applications. [ABSTRACT FROM AUTHOR]

Spiders (order Araneae) rely on their silks for essential tasks, such as dispersal, prey capture, and reproduction. Spider silks are largely composed of spidroins, members of a protein family that are synthesized in silk glands. As needed, silk stored in silk glands is extruded through spigots on the spinnerets. Nearly all studies of spider silks have been conducted on females; thus, little is known about male silk biology. To shed light on silk use by males, we compared silk gene expression profiles of mature males to those of females from three cob-web weaving species (Theridiidae). We de novo assembled species-specific male transcriptomes from Latrodectus hesperus , Latrodectus geometricus , and Steatoda grossa followed by differential gene expression analyses. Consistent with their complement of silk spigots, male theridiid spiders express appreciable amounts of aciniform, major ampullate, minor ampullate, and pyriform spidroin genes but not tubuliform spidroin genes. The relative expression levels of particular spidroin genes varied between sexes and species. Because mature males desert their prey-capture webs and become cursorial in their search for mates, we anticipated that major ampullate (dragline) spidroin genes would be the silk genes most highly expressed by males. Indeed, major ampullate spidroin genes had the highest expression in S. grossa males. However, minor ampullate spidroin genes were the most highly expressed spidroin genes in L. geometricus and L. hesperus males. Our expression profiling results suggest species-specific adaptive divergence of silk use by male theridiids. [ABSTRACT FROM AUTHOR]

Many adult male spiders have silk glands which are not associated with the spinnerets. They occur on the anterior margin of the genital furrow and are used during the building of the sperm web and sperm droplet induction. These epiandrous glands exit the body through ducts which lead to specialized spigots. In the taxon Mygalomorphae, the presence of epiandrous spigots is just reported for a couple of species but their morphology has not been investigated. In this paper we provide a detailed study of the ultrastructure morphology of eighteen species belonging to eight families using light and scanning electron microscopy (SEM). We describe and present images of the epiandrous spigots above the genital opening. Also, we compare the morphology of spigots between families and describe the epiandrous glands through histology. [ABSTRACT FROM AUTHOR]

During its life cycle, the cribellate spider Austrochilus sp. passes through the ecribellate nymphal, or spiderling stage (= the first instar, after leaving the egg sac), which has three pairs of spinnerets. According to the position and distribution of spigots on the spinnerets, these spigots are assumed to be connected to glandulae ampullaceae major, glandulae ampullaceae minor, glandulae piriformes and glandulae aciniformes. Such a spinning apparatus allows spiderlings to make draglines, attachment discs and silk for the molting platform. The cribellum, just like the calamistrum, is not developed in this stage. Instead the precribellum is present, which is similar to spinnerets in its shape (two protuberances divided by a groove and the presence of setae that look like spigots), but with a cuticle similar to the cribellum. The spinning apparatus of Austrochilus sp. shows one possible way in which the transformation of the anterior median spinnerets into the cribellum could have occurred during the evolution of silk-producing organs. In the following nymphal stage, the cribellum, the calamistrum and also the paracribellum are developed. Spiders in this stage are capable, after dispersal, of weaving complete webs, which serve as snares as well as retreats. The spigots of the paracribellum are on the posterior median and posterior lateral spinnerets. [ABSTRACT FROM AUTHOR]

External studies of spider spinning fields allow us to make inferences about internal silk gland biology, including what happens to silk glands when the spider molts. Such studies often focus on adults, but juveniles can provide additional insight on spinning apparatus development and character polarity. Here we document and describe spinning fields at all stadia in two species of pirate spider (Mimetidae: Australomimetus spinosus, A. djuka). Pirate spiders nest within the ecribellate orb-building spiders (Araneoidea), but are vagrant, araneophagic members that do not build prey-capture webs. Correspondingly, they lack aggregate and flagelliform silk glands (AG, FL), specialized for forming prey-capture lines in araneoid orb webs. However, occasional possible vestiges of an AG or FL spigot, as observed in one juvenile A. spinosus specimen, are consistent with secondary loss of AG and FL. By comparing spigots from one stadium to tartipores from the next stadium, silk glands can be divided into those that are tartipore-accommodated (T-A), and thus functional during proecdysis, and those that are not (non-T-A). Though evidence was more extensive in A. spinosus, it was likely true for both species that the number of non- T-A piriform silk glands (PI) was constant (two pairs) through all stadia, while numbers of T-A PI rose incrementally. The two species differed in that A. spinosus had T-A minor ampullate and aciniform silk glands (MiA, AC) that were absent in A. djuka. First instars of A. djuka, however, appeared to retain vestiges of T-A MiA spigots, consistent with a plesiomorphic state in which T-A MiA (called secondary MiA) are present. T-A AC have not previously been observed in Australomimetus and the arrangement of their spigots on posterior lateral spinnerets was unlike that seen thus far in other mimetid genera. Though new AC and T-A PI apparently form throughout much of a spider's ontogeny, recurring spigot/tartipore arrangements indicated that AC and PI, after functioning during one stadium, were used again in each subsequent stadium (if non-T-A) or in alternate subsequent stadia (if T-A). In A. spinosus, sexual and geographic dimorphisms involving AC were noted. Cylindrical silk gland (CY) spigots were observed in mid-to-late juvenile, as well as adult, females of both species. Their use in juveniles, however, should not be assumed and only adult CY spigots had wide openings typical of mimetids. Neither species exhibited two pairs of modified PI spigots present in some adult male mimetids. [ABSTRACT FROM AUTHOR]

The novel SnO/ZnO nanotubes had been synthesized by a simple electrospinning method. The morphology and structure of the as-prepared SnO/ZnO nanotubes were characterized by SEM and TEM, which suggested the hollow structure of the nanotubes with average diameters ranged from 200 to 300 nm. The SnO/ZnO nanotubes show high initial discharge capacity of 1932 mA h g and maintain a reversible capacity of 584.5 mA h g even after 45 cycles at a current density of 168 mA g, endowing its potential application in lithium ion batteries. [ABSTRACT FROM AUTHOR]

The spider family Mysmenidae is reported from Tibet for the first time. Two new species, Chanea voluta sp. n. (male and female) and Mysmena lulanga sp. n. (male and female) are found in eastern Tibet in high altitude. Morphological descriptions, diagnoses and comparative photos are provided for the two new species. [ABSTRACT FROM AUTHOR]

Spider silk production has been studied intensively in the last years. However, capture threads of cribellate spiders employ an until now often unnoticed alternative of thread production. This thread in general is highly interesting, as it not only involves a controlled arrangement of three types of threads with one being nano-scale fibres (cribellate fibres), but also a special comb-like structure on the metatarsus of the fourth leg (calamistrum) for its production. We found the cribellate fibres organized as a mat, enclosing two parallel larger fibres (axial fibres) and forming the typical puffy structure of cribellate threads. Mat and axial fibres are punctiform connected to each other between two puffs, presumably by the action of the median spinnerets. However, this connection alone does not lead to the typical puffy shape of a cribellate thread. Removing the calamistrum, we found a functional capture thread still being produced, but the puffy shape of the thread was lost. Therefore, the calamistrum is not necessary for the extraction or combination of fibres, but for further processing of the nano-scale cribellate fibres. Using data from Uloborus plumipes we were able to develop a model of the cribellate thread production, probably universally valid for cribellate spiders. [ABSTRACT FROM AUTHOR]

The spider suborder Mesothelae, containing a single extant family Liphistiidae, represents a species-poor and ancient lineage. These are conspicuous spiders that primitively retain a segmented abdomen and appendage-like spinnerets. While their classification history is nearly devoid of phylogenetic hypotheses, we here revise liphistiid genus level taxonomy based on original sampling throughout their Asian range, and on the evidence from a novel molecular phylogeny. By combining morphological and natural history evidence with phylogenetic relationships in the companion paper, we provide strong support for the monophyly of Liphistiidae, and the two subfamilies Liphistiinae and Heptathelinae. While the former only contains Liphistius Schiödte, 1849, a genus distributed in Indonesia (Sumatra), Laos, Malaysia, Myanmar, Thailand, we recognize and diagnose seven heptatheline genera, all but three removed from the synonymy of Heptathela: i) Ganthela Xu & Kuntner, gen. n. with the type species G. yundingensis Xu, sp. n. is known from Fujian and Jiangxi, China; ii) a rediagnosed Heptathela Kishida, 1923 is confined to the Japanese islands (Kyushu and Okinawa); iii) Qiongthela Xu & Kuntner, gen. n. with the type species Q. baishensis Xu, sp. n. is distributed disjunctly in Hainan, China and Vietnam; iv) Ryuthela Haupt, 1983 is confined to the Ryukyu archipelago (Japan); v) Sinothela Haupt, 2003 inhabits Chinese areas north of Yangtze; vi) Songthela Ono, 2000 inhabits southwest China and northern Vietnam; and vii) Vinathela Ono, 2000 (Abcathela Ono, 2000, syn. n.; Nanthela Haupt, 2003, syn. n.) is known from southeast China and Vietnam. [ABSTRACT FROM AUTHOR]

Phoneutria boliviensis (F.O.P.-Cambridge 1897) is a medically important wandering spider distributed from Central America to northern South America. This study is the first description of the natural history of this species, and presents data on several aspects of its natural history: reproductive and prey wrapping behavior, postembryonic development, and habitats in the departments of Valle del Cauca and Quindio, Colombia. Prior to copulation, the male did not engage in any courtship from a distance, but instead climbed onto the female, adopting the typical copulation position of "modern wandering spiders" (position III). Females laid up to four egg sacs; between 430-1300 hatchlings emerged after 28-34 days. After hatching, spiderlings had a third claw on all their legs and built an irregular web, where they remained until the next molt. Sexual maturity occurred after 14-17 molts, and spiders matured 300-465 days after emerging from the egg sac. The species was found in disturbed habitats associated with both dry and wet tropical forests, usually on the ground with little litter. Spiders wrapped prey in silk, moving in a stereotypically circular pattern around the prey without manipulating threads with their legs. Attachments to the substrate involved rapid movements of the anterior spinnerets, while the others remained immobile. [ABSTRACT FROM AUTHOR]

Spiders are characterized by their spinning activity. Much of the current knowledge of the spinning apparatus comes from studies on orb web spiders and their relatives, whereas wolf spiders have been more or less neglected in this respect. Therefore, we studied developmental changes in the spinning apparatus of four wolf spiders ( Tricca lutetiana, Arctosa alpigena lamperti, Pardosa amentata, and Xerolycosa nemoralis) throughout their life cycles. Each of these lycosids has a stenochronous life cycle, but of varied length (from 1 to 3 years) and number of instars (from seven to ten). Use of the spinning apparatus begins in the first instar, after leaving the egg sac. Secondary ampullate, all piriform, and all but four aciniform glands are tartipore-accommodated. The tartipores, collared openings through which silk gland ducts pass during proecdysis, appear on the spinning field starting with the second instar. Tartipore-accommodated glands can function during proecdysis and their evolution corresponds with the way spiders secure themselves when molting. We suggest that the function of aciniform silk in juvenile wolf spiders is to serve as an ancillary 'scaffold' supporting the spider's body during ecdysis. [ABSTRACT FROM AUTHOR]

A new genus, Reductoonops, is established for a group of New World soft-bodied oonopine spiders, found from Mexico south to Chile, characterized by reduced size, a flattened clypeus, loss of the posterior median spinnerets, and often by loss of the four posterior eyes. Members of this group resemble those of Stenoonops Simon but lack the clump of short setae found on the dorsal surface of the palpal tarsus of both sexes in that genus, and often have four pairs of deep channels at the sides of the sternum, the most anterior pair of which demarcate a short, trapezoidal, anterior portion of the sternum. A total of 34 new species are described from Mexico ( chamela, armeria, niltepec, real, nubes, jabin), Costa Rica ( monte, lucha), Costa Rica and Panama ( naci), Panama ( almirante, escopeta, bayano), Jamaica ( ferry), Curaçao ( hato), Martinique ( diamant), Colombia ( marta, sasaima, meta, leticia), Ecuador ( tandapi, pichincha, tina, domingo, otonga, palenque, napo, jatun, hedlite, molleturo, celica, yasuni), the Galapagos Islands ( pinta), Peru ( carpish), and Chile ( elqui). [ABSTRACT FROM AUTHOR]

The simulation of the contraction flow of concentrated acrylic copolymer/1-butyl-3-methylimidazolium chloride (P(AN-co-IA)/[BMIM]Cl) solution through spinneret orifice was carried out for the design of suitable spinneret. Geometry and mathematical models were established according to rheological behaviours and material parameters. The effects of channel geometry on variation of viscosity were simulated and discussed in detail. The numerical results show that an increase in aspect ratio resulted in the decrease in viscosity and a decrease in entrance angle may reduce the size of 'dead' region near the corner. From numerical investigations, the geometry with aspect ratio of 3∶1 and entrance angle of 30° was found to be suitable optimum geometry for concentrated polymer solution during dry-jet wet spinning. [ABSTRACT FROM AUTHOR]

Abstract: We revise the relationships of the spider genus Cryptothele after reexamination of the morphology of the spinnerets, leg tarsal claws and maxillae with scanning electron microscopy. Cryptothele species have a particular conformation of the spinning field of the anterior lateral spigots that is typical of zodariids and close relatives: the field of major ampullate gland spigots, together with their strain sensilla, are invaginated within the field of piriform gland spigots. The implantation of the teeth on the inner side of the leg tarsal claws is also consistent with its placement among zodariids. We added Cryptothele to a morphological dataset of zodariid genera, together with the outgroups Homalonychus (Homalonychidae) and Penestomus (Penestomidae). The phylogenetic analysis concludes that the genus Cryptothele is a member of the subfamily Cydrelinae, which by priority is here considered a junior synonym of Cryptothelinae. Cryptothele specimens cover most of their body with soil particles which become consolidated as mud, and the debris is probably held in place by curved setae covered by long barbs. The spinnerets, which can be retracted and hidden, as well as the booklungs, are surrounded by a crown of thick setae that are densely covered by short barbs, protecting those areas against soil particles. Cryptothele are probably specialized to prey on termites, and their phylogenetic placement indicates that this diet specificity evolved two times independently in zodariids. [Copyright &y& Elsevier]

Résumé: Objectif: Les plaies de la filière génitale sont responsables d’hémorragies potentiellement graves du post-partum et sont souvent sous-estimées. L’objectif de ce travail a été d’analyser les particularités de prise en charge dans un centre d’accueil de référence des plaies de la filière génitale associées à une hémorragie grave de la délivrance (HDD). Patientes et méthodes: Toutes les femmes transférées pour prise en charge d’une HDD liée à une plaie de la filière génitale entre janvier 2008 et avril 2011 ont été incluses dans cette étude observationnelle. Deux populations de patientes avec plaie de la filière génitale ont été définies : patientes avec plaie dite « complexe » et patientes avec plaie dite « simple ». Résultats: Quarante-quatre patientes ont été prises en charge pour une plaie de la filière génitale. L’âge moyen des patientes était de 30,6ans (17–41ans). Toutes les patientes ont accouché par voie vaginale, avec l’aide d’une extraction instrumentale dans 70,5 % des cas. À l’exception d’une patiente, toutes les patientes avaient eu une révision du col et de la filière vaginale sous valve avant transfert. Vingt neuf patientes (70,7 %) avaient bénéficié d’une suture de la filière génitale dans leur maternité d’origine. Sur le site de transfert, les patientes, ayant une plaie dite « simple » ont, dans 54,5 % des cas, eu une prise en charge réanimatoire seule contre 33,3 % pour celles ayant une plaie dite « complexe ». Dans 39,4 % des cas une embolisation artérielle a été nécessaire pour le groupe de patientes avec plaies « complexe » contre 9,1 % dans le groupe plaie « simple ». Discussion et conclusion: Les plaies de la filière génitale sont une cause grave d’HDD. Leur prise en charge doit être multidisciplinaire associant des mesures rapides et adaptées (réanimation, embolisation et/ou chirurgie). La séquence de ces différents traitements est fonction de l’état clinique de la patiente et justifie d’un transfert dans un centre de référence surtout en cas de lésions compliquées de la filière génitale. [ABSTRACT FROM AUTHOR]

ABSTRACT Surface morphology and internal structure of polyvinylidene fluoride (PVDF) nanofibers were investigated in this study. PVDF nanofibers were electrospun by two types of spinnerets, nozzle and channel spinneret, with different contents of tetrabutylammonium chloride (TBAC) and at various take-up velocities. The new spinneret design, channel spinneret, resulted in thicker fibers while high β-phase content and small d-spacing were obtained, especially in the case of low TBAC content. And high TBAC content led to finer PVDF nanofibers with high β-phase content and small d-spacing compared to low TBAC content regardless of spinneret types, while an increase in take-up velocity did not have significant effect on both morphology and internal structure of PVDF nanofibers regardless of TBAC content. It suggests that electrostatic drawing acted dominantly rather than mechanically drawing in the system cooperating TBAC. However, the decreasing difference between two types of spinnerets was observed in terms of β-phase content with an increase in TBAC content. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1752-1758, 2013 [ABSTRACT FROM AUTHOR]

Abstract: Spinnerets from Phobetinus sagittifer and an undescribed Phobetinus species were examined by scanning electron microscopy to gain a better understanding of this genus' relationships to other genera in the family Mimetidae. Consistent with placement of Phobetinus in Mimetinae, females possessed two synapomorphies of this subfamily; enlarged cylindrical silk gland spigots with domed shafts and a single cylindrical spigot per posterior lateral spinneret (PLS). Spinning field features overall suggest Phobetinus is most closely related to Mimetus, followed by Australomimetus, then Ero. A possible synapomorphy of a clade including Mimetus and Phobetinus is a pair of modified piriform silk gland spigots on each anterior lateral spinneret of adult males located adjacent to the secondary major ampullate silk gland tartipore. These spigots were present in P. sagittifer; however, similarly positioned spigots in the undescribed species were not obviously modified (i.e., wider or with larger openings relative to the other piriform spigots). Close affinity to Mimetus was also indicated by tartipore-accommodated PLS aciniform silk glands in both Phobetinus species. These have been consistently observed in Mimetus, but not in Australomimetus or Ero. Somatic and genitalic drawings of P. sagittifer are provided to aid identification and similarities are noted between male pedipalps of Mimetus and Phobetinus. [Copyright &y& Elsevier]

Abstract: Several studies on tarantulas have claimed that their tarsi could secrete fine silk threads which would provide additional safety lines for maintaining a secure foot-hold on smooth vertical surfaces. This interpretation was seriously questioned by behavioral experiments, and more recently morphological evidence indicated that the alleged spigots (“ribbed hairs”) were not secretory but most likely sensory hairs (chemoreceptors). However, since fine structural studies were lacking, the sensory nature was not proven convincingly. By using transmission electron microscopy we here present clear evidence that these “ribbed hairs” contain many dendrites inside the hair lumen – as is the case in the well-known contact chemoreceptors of spiders and insects. For comparison, we also studied the fine structure of regular silk spigots on the spinnerets and found them distinctly different from sensory hairs. Finally, histological studies of a tarantula tarsus did not reveal any silk glands, which, by contrast, are easily found within the spinnerets. In conclusion, the alleged presence of silk spigots on tarantula feet is refuted. [Copyright &y& Elsevier]

The new spider genus and species Trogloraptor marchingtoni Griswold, Audisio & Ledford is described as the type of the new family Trogloraptoridae. The oblique membranous division of the basal segment of the anterior lateral spinnerets of Trogloraptor suggests that this haplogyne family is the sister group of the other Dysderoidea (Dysderidae, Oonopidae, Orsolobidae and Segestriidae). Trogloraptor is known only from caves and old growth forest understory in the Klamath-Siskiyou region of Oregon and California. [ABSTRACT FROM AUTHOR]

Although the basic taxonomic characteristics usually remain unchanged, some spinning apparatuses undergo consistent adaptive variations. As the presence of additional protuberances known as nubbins and tartipores have caused disagreements regarding some Araneidae spiders, more detailed definitions on the cuticular structures have recently been proposed. Reflecting this definition, microstructural organization of silk spinning apparatuses in the orb web spider Argiope bruennichi were reconsidered using field emission scanning electron microscopy. Among the seven kinds of functional spigots in females, it was revealed that two types (major ampullates and pyrifoms) are located on anterior spinnerets and another five types are distributed on median (minor ampullates, tubuliforms and aciniforms) or posterior (tubuliforms, flagelliforms, aggregates and aciniforms) spinnerets, respectively. In addition to functional spigots, cuticular remnants of the nubbins and the tartipores were found on the spinning fields, but the number of tartipores on each spinneret varied among individuals based on maturity. Nevertheless, three kinds of cuticular protuberances of ampullate silk glands were clearly visible at both the anterior and median spinnerets. [ABSTRACT FROM AUTHOR]

To counter female resistance to mating and cannibalism, males of many animal species have evolved a variety of behavioural adaptations. Here we investigated a novel copulatory courtship behaviour, mate binding, in which the male deposits fine silk onto the female’s body in between copulation bouts, in an orb-web nephilid spider, Nephila pilipes. We hypothesized that mate binding might reduce female aggressiveness and sexual cannibalism and that both tactile and chemical cues play a role. We performed a series of mating trials, in which we blocked (1) the females’ tactile perception, (2) the females’ chemoreceptors, and (3) both types of communication. We also manipulated male spinnerets and thus male silk production. As predicted, mate binding reduced both female resistance to repeated mating and levels of sexual cannibalism. Our results suggest that both tactile and chemical cues are crucial for mate binding to succeed in rendering females less aggressive, but that tactile cues are more important. We conclude that mate binding prolongs total copulation duration, whereby the male maximizes his paternity. Therefore, mate binding may serve as a mechanism countering sexual conflict over repeated mating and sexual cannibalism. [ABSTRACT FROM AUTHOR]

A cocoon produced by a juvenile Prolysiopetalum scabratum (L. Koch, 1867) is described and illustrated. SEM pictures of the threads are provided and previous literature on spinning in callipodidan millipedes is reviewed. [ABSTRACT FROM AUTHOR]

A new process technology modified from conventional coaxial electrospinning process has been developed to prepare polymer fibers from a high concentration solution. This process involves a pure solvent concentrically surrounding polymer fluid in the spinneret. The concentric spinneret was constructed simply by inserting a metal needle through a high elastic silica gel tube. Two syringe pumps were used to drive the core polymer solution and the sheath solvent. Using polyvinylpyrrolidone (PVP) as the polymer model, which normally has an electrospinnable concentration of 10% w/v in ethanol, it was possible to electrospin 35% w/v of PVP in the same solvent, when pure N, N-dimethylacetamide (DMAc) was used as sheath fluid. The resultant fibers have a smooth surface morphology and good structural uniformity. The diameter of the fibers was 2.0±0.25 μm when the DMAc-to-polymer-solution flow rate ratio was set as 0.1. The process technology reported here opens a new window to tune the polymer fibers obtained by the electrospinning, and is useful for improving productivity of the electrospinning process. [ABSTRACT FROM AUTHOR]

This paper discusses the possible functional significance of the locations of the spigots of different types of silk gland on the different spinnerets of spiders. Deductions are based on recognition that some types of line are initiated by being attached to the dragline, that there is an anterior-posterior asymmetry in how such lines can be initiated, and that spigot location also affects the possibility of attaching lines to the substrate. Possible explanations are given for several morphological details, including the anterior location of the dragline, piriform and cribellum spigots, planar arrays of piriform and cribellum spigots, and posterior location of aciniform spigots. I argue that piriform gland products are not used to attach egg sac lines to each other, that sticky wrapping lines are initiated in theridiids and pholcids by attaching them to draglines and that lines from both aciniform and cylindriform glands are laid along with liquid that renders them sticky. The possible role of phylogenetic inertia in determining spigot locations is discussed. Further work is needed to determine whether termination of lines and accessibility of spigots for cleaning also influence their positions. [ABSTRACT FROM AUTHOR]

Abstract: The prosoma of spiders bears different gnathal (labrum, chelicerae, pedipalps) and locomotory appendages (legs). In most species these appendages are also used for additional functions, e.g. sensing, mating, and courtship. The opisthosoma is equipped with four pairs of highly specialized appendages. Two pairs of spinnerets are used for silk production and manipulation. The other two pairs of appendages are internalized during development and give rise to a complex respiratory system of book lungs and tracheae. Thus spiders have a number of different appendage types with radically different adult morphologies. Furthermore, all these appendage types display significant additional species specific diversity correlating with a large spectrum of functions of the appendages. Despite this importance of appendage diversity for the evolution of the spiders we know relatively little about the genetic patterning mechanisms producing this diversity of morphology. We review recent advances concerning the developmental genetics of spider appendage diversification, mainly concentrating on open questions and future directions of research. We conclude that the deeper understanding of appendage development and diversity in spiders can contribute significantly not only to evolutionary developmental biology, but also to behavioral biology, speciation research and population genetics, and the study of sexually dimorphic traits. [ABSTRACT FROM AUTHOR]

In this paper, we describe the construction and function of the double sheet and tangle web of Tidarren sisyphoides (Walckenaer 1842). Web construction includes several stages: construction of the scaffolding that serves to support the rest of the web; filling in the dome-shaped and horizontal sheets; and construction of the upper tangle. During construction of the scaffolding, the spider descends by a pre-existing thread to the substrate, moves a few centimeters and attaches the dragline, then she ascends by the new thread, doubling the line or attaching it to another thread. The spider fills in the sheet while walking in an irregular pattern under the sheet, and attaching her dragline using either one or both legs IV simultaneously to hold pre-existing sheet lines against her spinnerets. During scaffolding construction and filling in the dome-shaped sheet, the spider returns frequently to the retreat, apparently using the same threads near the retreat each time. Threads of both the dome-shaped sheet and the horizontal sheet have small drops of viscid material. The dome-shaped sheet and upper tangle comprise the functional trap of the web, while the horizontal sheet apparently plays only a little role in prey capture. [ABSTRACT FROM AUTHOR]

The sticky viscous capture threads in araneoid orb-webs are responsible for retaining insects that strike these webs. We used features of 16 species' threads and the stickiness that they expressed on contact plates of four widths to model their adhesive delivery systems. Our results confirm that droplets at the edges of thread contact contribute the greatest adhesion, with each successively interior droplet contributing only 0.70 as much adhesion. Thus, regardless of the size and spacing of a thread's large primary droplets, little adhesion accrues beyond a span of 20 droplets. From this pattern we computed effective droplet number (EDN), an index that describes the total droplet equivalents that contribute to the stickiness of thread spans. EDN makes the greatest positive contribution to thread stickiness, followed by an index of the shape and size of primary droplets, and.the volume of small secondary droplets. The proportion of water in droplets makes the single greatest negative contribution to thread stickiness, followed by a thread's extensibility, and the area of flattened droplets. Although highly significant, this six-variable model failed to convincingly describe the stickiness of six species, a problem resolved when species were assigned to three groups and a separate model was constructed for each. These models place different weights on the variables and, in some cases, reverse or exclude the contribution of a variable. Differences in threads may adapt them to particular habitats, web architectures or prey types, or they may be shaped by a species' phylogeny or metabolic capabilities. [ABSTRACT FROM AUTHOR]

Silkworms can produce strong and tough fibers at room temperature and from an aqueous solution. Therefore, it seems useful to study the mechanism of fiber formation by silkworms for development of synthetic polymers with excellent mechanical properties. The rheological behaviors of native silk dopes stored in the silk glands of Bombyx moriand Samia cynthia riciniwere clarified, and flow simulations of the dopes in each spinneret were performed with a Finite Element Method. Dynamic viscoelastic measurements revealed that silk fibroin stored in silk glands forms a transient network at room temperature, and that the molecular weight for the network node corresponds to the molecular weight of a heterodimer of H-chain and L-chain (B. mori) and a homodimer of H-chains (S. c. ricini), respectively. Also, each dope exhibited zero-shear viscosity and then shear thinning like polymer melts. In addition, shear thickening due to flow-induced crystallization was observed. The critical shear rate for crystallization of B. moridopes was smaller than that of S. c. ricinidopes. From the flow simulation, it is suggested that domestic and wild silkworms are able to crystallize the dopes in the stiff plate region by controlling shear rate using the same magnitude of extrusion pressure despite differences in rheological properties. [ABSTRACT FROM AUTHOR]

Representatives of 23 genera from 18 families of the milliped order Polydesmida were examined using optical and scanning electron microscopy. The fiber-spinning structures reported by Adis et al. (2000) from two pyrgodesmid polydesmidans were found on all specimens studied, though their arrangement and structure differed; a cluster with each of four spinnerets set in contiguous walled depressions was characteristic only of some families of the suborder Polydesmidea. Corresponding structures in some adults of the suborders Leptodesmidea and Paradoxosomatidea appeared nonfunctional and were not set in contiguous walled depressions. Spinnerets of members of the orders Chordeumatida and Callipodida are structurally similar to those of the polydesmidans, but putative spinnerets in the orders Siphoniulida and Stemmiulida show differences. The presence of these spinning organs may be a synapomorphy of polydesmidans and the nematophoran orders, supporting the view that Polydesmida is a member of the "eighth gonopod clade" postulated by Shear, Shelley and Heatwole (2003), and is not close to either Juliformia or Colobognatha. [ABSTRACT FROM AUTHOR]

Silk production from opisthosomal glands is a defining characteristic of spiders (Araneae). Silk emerges from spigots (modified setae) borne on spinnerets (modified appendages). Spigots from Attercopus fimbriunguis, from Middle Devonian (386 Ma) strata of Gilboa, New York, were described in 1989 as evidence for the oldest spider and the first use of silk by animals. Slightly younger (374 Ma) material from South Mountain, New York, conspecific with A. fimbriunguis, includes spigots and other evidence that elucidate the evolution of early Araneae and the origin of spider silk. No known Attercopus spigots, including the original specimen, occur on true spinnerets but are arranged along the edges of plates. Spinnerets originated from biramous appendages of opisthosomal somites 4 and 5; although present in Limulus, no other arachnids have opisthosomal appendage homologues on these segments. The spigot arrangement in Attercopus shows a primitive state before the reexpression of the dormant genetic mechanism that gave rise to spinnerets in later spiders. Enigmatic flagellar structures originally described as Arachnida incertae sedis, are shown to be Attercopus anal flagella, as found in Permarachne, also originally described as a spider. An arachnid order, Uraraneida, is erected for a plesion, including these two genera, based on this combination of characters. The inability of Uraraneida precisely to control silk weaving suggests its original use as a wrapping, lining, or homing material. [ABSTRACT FROM AUTHOR]

Representatives of 23 genera from 18 families of the milliped order Polydesmida were examined using optical and scanning electron microscopy. The fiber-spinning structures reported by Adis et al. (2000) from two pyrgodesmid polydesmidans were found on all specimens studied, though their arrangement and structure differed; a cluster with each of four spinnerets set in contiguous walled depressions was characteristic only of some families of the suborder Polydesmidea. Corresponding structures in some adults of the suborders Leptodesmidea and Paradoxosomatidea appeared nonfunctional and were not set in contiguous walled depressions. Spinnerets of members of the orders Chordeumatida and Callipodida are structurally similar to those of the polydesmidans, but putative spinnerets in the orders Siphoniulida and Stemmiulida show differences. The presence of these spinning organs may be a synapomorphy of polydesmidans and the nematophoran orders, supporting the view that Polydesmida is a member of the "eighth gonopod clade" postulated by Shear, Shelley and Heatwole (2003), and is not close to either Juliformia or Colobognatha. [ABSTRACT FROM AUTHOR]

A new genus of Amaurobiidae, Himalmartensus, is described from Nepal, and includes three species: the type species H. martensi new species, H. ausobskyi new species, and H. nepalensis new species. Members of this new genus can be separated from other amaurobiid genera by the combination of the following characters: the presence of a colulus, a single chilum, smooth trichobothrial bases, and simple tracheal tubes. Both promargin and retromargin of Himalmartensus chelicerae have 5-8 teeth and the female epigynum is modified with long and looping copulatory ducts. The spinnerets of all three new species are described and tracheal tubes of H. martensi are examined. Spinnerets, colulus, chilum and tracheal tubes of Himalmartensus are compared to similar genera, including amaurobiids, agelenids, and cybaeids. Himalmartensus is defined as a member of the family Amaurobiidae because of its similarity to the amaurobiids Rubrius and Macrobunus. [ABSTRACT FROM AUTHOR]

The effect of the drawing process on the structural characteristics and mechanical properties of polyacrylonitrile (PAN) fibers was comparatively studied. The protofibers extruded from the spinneret were the initial phase of stretching, which involved the deformation of the primitive fiber with the concurrent orientation of the fibrils. Wet‐spun PAN fibers observed by scanning electron microscopy exhibited different cross‐sectional shapes as the draw ratio was varied. X‐ray diffraction results revealed that the crystalline orientation of PAN fibers increased with increasing draw ratio; these differences in the orientation behaviors were attributed to the various drawing mechanisms involved. The crystalline and amorphous orientations of the PAN fibers showed different features; at the same time, the tensile properties were strongly dependent on the draw ratio. However, the stream stretch ratio had most influence on the tensile strength and the orientation of PAN fibers for the selected process parameters. Electron spin resonance proved that the local morphology and segmental dynamics of the protofibers were due to a more heterogeneous environment caused by the sequence structure. Differential scanning calorimetry indicated that the size and shape of the exotherm and exoenergic reaction were strongly dependent on the morphology and physical changes occurring during fiber formation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1026–1037, 2007 [ABSTRACT FROM AUTHOR]

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Abstract: This study provides comprehensive documentation of silk production in the pest moth Helicoverpa armigera from gland secretion to extrusion of silk thread. The structure of the silk glands, accessory structures and extrusion apparatus are reported. The general schema of the paired silk glands follows that found for Lepidoptera. Morphology of the duct, silk press, muscle attachments and spigot are presented as a three-dimensional reconstruction and the cuticular crescent-shaped profile of the silk press is demonstrated in both open and closed forms with attendant muscle blocks, allowing advances in our knowledge of how the silk press functions to regulate the extrusion of silk. Growth of the spigot across instars is documented showing a distinctive developmental pattern for this extrusion device. Its shape and structure are related to use and load-bearing activity. [Copyright &y& Elsevier]

The microstructural organization of the silk-spinning apparatus of the comb-footed spider, Achaearanea tepidariorum, was observed by using a field emission scanning electron microscope. The silk glands of the spider were classified into six groups: ampullate, tubuliform, flagelliform, aggregate, aciniform and pyriform glands. Among these, three types of silk glands, the ampullate, pyriform and aciniform glands, occur only in female spiders. One (adult) or two (subadult) pairs of major ampullate glands send secretory ductules to the anterior spinnerets, and another pair of minor ampullate glands supply the median spinnerets. Three pairs of tubuliform glands in female spiders send secretory ductules to the median (one pair) and posterior (two pairs) spinnerets. Furthermore, one pair of flagelliform glands and two pairs of aggregate glands together supply the posterior spinnerets, and form a characteristic spinning structure known as a “triad” spigot. In male spiders, this combined apparatus of the flagelliform and the aggregate spigots for capture thread production is not apparent, instead only a non-functional remnant of this triad spigot is present. In addition, the aciniform glands send ductules to the median (two pairs) and the posterior spinnerets (12–16 pairs), and the pyriform glands feed silk into the anterior spinnerets (90–100 pairs in females and 45–50 pairs in males). [ABSTRACT FROM AUTHOR]