Natural Spider Research Articles

Ultrathin Spider Silk Films: Insights into Spider Silk Assembly on Surfaces

β-Sheets in natural spider dragline silk proteins are typically formed by polyalanine (An) as well as alanine-glycine (AG) and GGA sequences flanking these An regions. The hydrophobic β-sheet-rich ...

In vitro construction of artificial blood vessels using spider silk as a supporting matrix

Recent research has vigorously pursued the development of tissue-engineered vascular grafts (TEVs). One of the striking points of the early phase is the instability of the artificial blood vessels and lack of vascular resistance, which is supposed to be a consequence of unstable scaffolds. Therefore, alternative biological approaches are necessary to improve the physical properties of the artificial vessel walls.We developed blood vessel-like constructs based on native spider silk as a scaffold. C2C12 and ST1.6R cells were seeded on the surface of scaffolds and cultivated under pulsatile flow (max. ~135 mmHg and min. ~90 mmHg) in a bioreactor. Constructed grafts were compared to human blood vessels and cell seeded scaffolds cultured in the absence of bioreactor. Mechanical properties, morphological structures and expression of marker genes were assessed by strength and strain experiments, SEM, histological staining, immunohistology, Western blotting and quantitative real-time PCR. The results indicate that the constructed vessel resembles native blood vessels in morphological structure as well as in function and expression of biomarkers. Spider silk scaffolds seem to provide an optimal and stable basis for vessel constructs.

Identification, genomic organization and expression pattern of glutathione transferase in Pardosa pseudoannulata

The pond wolf spider, Pardosa pseudoannulata, is one of the dominant natural enemies in farmlands and plays important roles in controlling a range of insect pests. The spider is less sensitive to many insecticides than the target pests such as the brown planthopper, Nilaparvata lugens. The different sensitivity to a certain insecticide between species is mostly attributed to the differences in both molecular targets and detoxification enzymes. As one of the most important detoxification enzymes, glutathione transferases (GSTs) play a key role as phase II enzyme in the enzymic detoxification in organisms. Until now, there are few studies on spiders' GSTs, limiting the understanding of insecticide selectivity between insect pests and natural enemy spiders. In this study, based on the transcriptome and genome sequencing of P. pseudoannulata, thirteen full-length transcripts encoding GSTs were identified and analyzed. Interestingly, Delta family, which is thought to be specific to the Insecta, was identified in P. pseudoannulata. Further, vertebrate/mammalian-specific Mu family was also identified in P. pseudoannulata. The mRNA expression levels of cytosolic GSTs in different tissues were determined, and most GST genes were abundant in the gut and the fat body. To investigate GST candidates involving in insecticide detoxification, the mRNA levels of cytosolic GSTs were tested after spiders' exposure to either imidacloprid or deltamethrin. The results showed that PpGSTD3 and PpGSTT1 responded to at least one of these two insecticides. The present study helped understand the function of GSTs in P. pseudoannulata and enriched the genetic information of natural enemy spiders.

Flower strip farmscaping to promote natural enemies diversity and eco-friendly pest suppression in okra (Abelmoschus esculentus)

Investigations were conducted on flower strip farmscaping along with intercropping to promote natural enemy diversity and eco-friendly pest suppression in okra during kharif 2016 and 2017. Pooled data of both the years revealed that whitefly was lowest (7.66 /15 leaves) in biopesticides treated okra having baby-corn as an intercrop with flower plants strip. Likewise, a minimum population of leafhoppers (39.89/15 leaves), red spider mites (99.16/cm2/15 leaves) and lowest fruit infestation by fruit borer (9.60%) were observed on treated okra having cowpea as an intercrop with flower strip farmscaping. Maximum population of natural enemies, viz. coccinellids (5.40), spiders (6.38), Geocoris bug (2.47), rove beetles (1.99/5 plants) and carabid beetles (1.32/2 pitfall traps) were recorded on untreated okra with cowpea intercropping having flower strip farmscaping. Shannon-wiener index value was found lower for pests on okra treatments having flower strips, while index value was higher for natural enemies on same treatments.

Natural spider silk as a photonics component for humidity sensing.

Biological microfibers are remarkable materials with diversity in their chemistry, structure and functions that provide a range of solutions for photonic structures. Here we proposed and demonstrated a humidity detection technique for spectral tuning of whispering gallery modes (WGMs) in a cylindrical microresonator formed by a piece of spider egg sac silk (SpEss) from Araneus Ventricosus. We launched a supercontinuum laser into the SpEss via a tapered single-mode fiber to excite WGMs. When the ambient humidity changed, the profile diameter and effective refractive index of the SpEss changed, which caused the WGM resonant dips to shift. The experimental results showed that when the relative humidity (RH) changed from 20% to 75% RH, the average testing sensitivity of the proposed sensor was 389.1 pm/%RH and the maximum testing sensitivity was 606.7 pm/%RH in the range of 60% to 75% RH. Also, the proposed SpEss-based humidity sensor showed a fast response time of 494 ms and good repeatability with fluctuations less than 8% compared with the initial test values. The SpEss-based sensor expanded the application of spider silk as a biodegradable and biocompatible material in biochemical sensing.

Can native plantings encourage native and beneficial invertebrates on Canterbury dairy farms?

ABSTRACTFarming intensification negatively effects native habitat and associated biodiversity in New Zealand. Planting native species around field margins has been proposed as a means of restoring biodiversity within this highly modified landscape. To test this hypothesis, we collected invertebrates on a dairy farm at Lincoln, Canterbury, in three habitat types: native plantings in field corners, native plantings along a double fence line, and pasture. Invertebrates were collected from pitfall traps, yellow pan traps, wooden discs and leaf litter samples were collected from the sites over summer. Assemblages of spiders, flying insects, slugs and litter mites in the planted areas had distinct compositions compared with those found in adjacent pasture. Species richness of native spiders was increased in the planted areas compared with adjacent pasture, as was the abundance of ecosystem service providers, such as honeybees, parasitoid wasps and hoverflies. Exotic slugs were significantly more abundant under discs in pasture than in planted areas. However, not all native or beneficial invertebrates responded positively to the planted areas. Further research is required to examine whether these results are repeatable at other locations, if invertebrate assemblages at this location develop further over time, and to evaluate whether any perceived benefits of these service providers can be quantified in terms of meaningful endpoints such as reduced pest levels and/or increases in yield.

Advanced Recombinant and Regenerated Silk Materials for Medicine and Tissue Engineering

A spiderweb is one of the strongest natural materials. The strength of its filaments can reach 1.3–1.5 GPa, which is comparable to the strength of steel. Its toughness reaches enormous values of 194–283 MJ/m3; therefore, textiles based on spider yarns may be promising in the production of composite materials for aircraft and automobiles. Spiderweb fibers have high biocompatibility and antibacterial properties, support cell viability, and do not cause an immune response. Thus, they can be used for manufacturing three-dimensional porous cell scaffolds for tissue engineering purposes. The undoubted advantages of spiderweb fibers include the fact that they do not melt. Therefore, textile products made of spider silk can be used for the production of military equipment. Unfortunately, mass production of spider silk using breeding of spiders is not possible. In this regard, development of synthetic analogues using recombinant DNA technology is of current interest. In order to create the technology for manufacturing artificial silk fiber and medical materials, this review presents the main findings in studying the rheological properties of solutions of spidroin (the main web material) and silk fibroin. These findings demonstrated how structural transformations of spidroin are induced by a change in the pH, salt content, and shear stress, and determine its ability for self-organization in aqueous solutions. An analysis of the most important studies of wet, dry–wet spinning, and electrospinning of fibers is presented, as is a comparison of the mechanical properties of the fibers of recombinant spidroin and natural spider fibers. Significant recent successes in this area allow us to advance toward the creation of a new generation of fibrous materials.

Interpreting and responding to ambiguous natural images in spider phobia

Background and objectivesThe fast detection of and response to threatening stimuli is an important task of the human visual and motor systems, and is especially challenging when stimuli are ambiguous. This study investigates the perception, evaluation and fast response to ambiguous natural spider stimuli in spider-fearful and non-anxious participants. MethodsStimuli were created by gradually morphing natural images of spiders and non-spiders (a crab, a starfish, a bunch of keys, and a flower). In Study 1, participants rated the images on perceptual and emotional dimensions and responded to them in a response priming task to measure rapid information processing. In Study 2, results were validated and extended in a different paradigm by using a go/no-go task. ResultsAs expected, spider-fearful participants showed an interpretative bias for ambiguous stimuli (i.e., perceived them as more similar to spiders) and rated spider(-like) stimuli as more unpleasant, arousing, and disgusting. In Study 1, spider stimuli were preferentially processed in spider-fearful participants as observed in faster responses to spider targets–however, responses were not different to comparison participants for ambiguous stimuli. Study 2 suggests that this finding can be explained by differences in stimulus duration. LimitationsNo participants with positive attitudes towards spiders or a second fearful comparison group were included. ConclusionsWe suggest that these findings can be explained by the nature of the applied tasks that tap into early phases of visual processing, thereby relying on feedforward-mediated low-spatial-frequency information extracted via the fast, subcortical path to the amygdala.

Optically Active Hybrid Materials Based on Natural Spider Silk.

Spider silk is a natural material possessing unique properties such as biocompatibility, regenerative and antimicrobial activity, and biodegradability. It is broadly considered an attractive matrix for tissue regeneration applications. Optical monitoring and potential control over tissue regrowth are attractive tools for monitoring of this process. In this work, we show upconversion modification of natural spider silk fibers with inorganic nanoparticles. To achieve upconversion, metal oxide nanoparticles were doped with low concentrations of rare-earth elements, producing potentially biocompatible luminescent nanomaterials. The suggested approach to spider silk modification is efficient and easy to perform, opening up sensing and imaging possibilities of biomaterials in a noninvasive and real-time manner in bio-integration approaches.

CRISPR/Cas9 Initiated Transgenic Silkworms as a Natural Spinner of Spider Silk.

Using transgenic silkworms with their natural spinning apparatus has proven to be a promising way to spin spider silk-like fibers. The challenges are incorporating native-size spider silk proteins and achieving an inheritable transgenic silkworm strain. In this study, a CRISPR/Cas9 initiated fixed-point strategy was used to successfully incorporate spider silk protein genes into the Bombyx mori genome. Native-size spider silk genes (up to 10 kb) were inserted into an intron of the fibroin heavy or light chain (FibH or FibL) ensuring that any sequence changes induced by the CRISPR/Cas9 would not impact protein production. The resulting fibers are as strong as native spider silks (1.2 GPa tensile strength). The transgenic silkworms have been tracked for several generations with normal inheritance of the transgenes. This strategy demonstrates the feasibility of using silkworms as a natural spider silk spinner for industrial production of high-performance fibers.

Conservation biological control using Australian native plants in a brassica crop system: seeking complementary ecosystem services

Habitat management can enhance the strength of ecosystem services but carries also the risk of leading to ecosystem disservices unless trophic links and ecosystem functions are well understood. In this study, intercropping with Australian native flowering plants was compared with the use of an exotic plant, buckwheat (Fagopyrum esculentum) and naturally occurring weedy grass vegetation for the provision of multiple ecosystem services in a cabbage agroecosystem. Among the native plants studied, Mentha satureioides had the most comprehensive positive effects on pest management. Compared with the grassy control, M. satureiodides significantly enhanced parasitism of the pest, Plutella xylostella (L.) (Lepidoptera: Plutellidae) larvae and reduced pest Brevicoryne brassicae densities and was comparable to F. esculentum. Flowers of M. satureiodides appeared attractive to adult Pieris rapae and the adjacent cabbage foliage held high densities of this pest’s eggs but, reflecting high densities of parasitoids and predators (especially spiders), larval densities were not elevated compared to other treatments. Lotus australis also enhanced natural enemies, especially coccinellids and spiders, but this did not translate into the ecosystem service of pest suppression. Swainsona galegifolia harboured elevated numbers of spiders but the adjacent crop did not benefit from enhanced enemy densities or suppressed pests. For complementary ecosystem services, pollinator abundance was enhanced by the exotic plant F. esculentum and two natives (L. australis and M. satureioides). Honey bees (Apis mellifera) were highly attracted to F. esculentum, while native bees were attracted to the native plants. Native butterflies were monitored as a proxy for benefit to native invertebrate biodiversity and two native plants (L. australis and M. satureioides) were found to be attractive. Soil biological activity, a proxy for soil-associated ecosystem services, was lower in the F. esculentum treatment compared to all other treatments. These results show scope for farmers to take advantage of particular, and potentially multiple, ecosystem services by incorporating native flowering plants into farming systems but highlights the importance of plant selection and the risk of trade-offs among services.

Fibers Made of Recombinant Spidroins—A Brief Review

Spider silk is a promising biomaterial, with a wide range of potential applications in the medical, military, and commercial sectors. In the past decade, researchers have been developing recombinant spider silk (RSS) proteins with the help of advanced genetic engineering techniques, including gene design, cloning, and protein expression in different foreign hosts. The extraordinary strength and extensibility of natural spider silk fiber are constituted from the tandemly repeated amino acid sequences and antiparallel crystalline β-sheet segments formed by polyalanine motifs. Additionally, mechanical properties are also influenced by extrusion and drawing of fibers in the natural spinning process. To date, the wet spinning process was found to be a commercially successful method for spinning recombinant silks with properties comparable to their natural counterparts.

Maintenance of deceptive gifts in a natural spider population: ecological and demographic factors

AbstractAlternative mating tactics are expected to occur predominantly when mate competition is intense, resources are in short supply, or as a result of asymmetric power relationships between individuals. Males of the nuptial gift-giving spider Pisaura mirabilis use a prevailing tactic of offering a nutritive gift (insect prey) and a deceptive tactic of offering a worthless gift (consumed prey) to prospective mates. If the male’s tactic depends on precopulatory male–male competition, worthless gifts should occur primarily late in the season, when the operational sex ratio (OSR) becomes male-biased. If it depends on resource availability and/or postcopulatory sexual selection (sperm competition), worthless gifts should occur mostly early in the mating season, when prey availability is low and most females are unmated (i.e., postcopulatory sexual selection is weak). Nuptial gift construction correlated positively with prey availability and negatively with OSR, suggesting that males increase reproductive effort when resource and mate availability increase. We did not find evidence for body condition affecting male tactic use. Male size had a marked effect on the reproductive tactic employed. Males that matured early in the season were very small and employed mostly the nutritive gift tactic during their short life. Among the males that matured later and persisted through the season, relatively small males employed the worthless gift tactic whereas large males employed the nutritive gift tactic. We suggest that the existence of 2 distinct life-history strategies among males (early small and late large size) interacts with environmental and demographic conditions to maintain the deceptive tactic.

Sown wildflower strips as overwintering habitat for arthropods: Effective measure or ecological trap?

Wildflower strips (WFS) are increasingly commonly adopted measures to promote biodiversity in agro-ecosystems. While their effectiveness in providing floral and other food resources for pollinators and natural enemies has been relatively well studied, much less is known about the value of different types of WFS as overwintering habitat for different functional arthropod groups. Here, we examined arthropod overwintering in WFS of different age compared to winter wheat fields. Moreover, we addressed the largely unexplored question to what extent non-permanent WFS may act as sink or ecological trap, if they attract high numbers of overwintering arthropods but only a low proportion of them survive and successfully emerge due to ploughing of strips during overwintering.Overwintering of all studied arthropod groups including potential pest natural enemies spiders, carabid beetles, staphylinid beetles and different families of pollinating flies was higher in WFS compared to winter wheat crops. Overwintering increased in WFS compared to wheat fields irrespective of WFS age, except for 4 year old WFS in the case of carabid beetles and 1 year old WFS in the case of spiders. While WFS age positively affected spider overwintering, numbers of overwintering pollinating flies and staphylinid beetles did not change significantly with WFS age. Moreover, carabid beetles tended to decline in the four years old WFS compared to younger ones. Ploughing of annual WFS during overwintering significantly reduced the number of successfully emerging arthropods by 59% on average. Detrimental effects were strongest for carabid beetles and spiders (reductions by 67% and 69%, respectively) to their numbers in ploughed WFS being similar to winter wheat fields. Reductions were less severe for pollinating flies and staphylinid beetles (both 47%), with higher numbers emerging from annual WFS compared to winter wheat fields even after ploughing of WFS.We conclude that perennial WFS are valuable overwintering habitats for a range of arthropod taxa across functional groups in arable cropping systems. Distinct responses of different arthropod taxa to WFS age highlight the importance of managing perennial WFS of various successional stages in order to promote overwintering of a broad variety arthropods in agro-ecosystems. Our study raises concerns, however, that annual WFS ploughed during the overwintering period are poor overwintering habitats for arthropods and may even act as ecological traps.

Short-Term Response of Two Beneficial Invertebrate Groups to Wildfire in an Arid Grassland System, United States

Rangeland invertebrates contribute greatly to biodiversity and provide important services including pollination, pest control, and nutrient cycling. As wildfire frequency increases across these areas of the United States, it is imperative to understand how these disturbances affect beneficial invertebrate communities. We examined bee (Hymenoptera), spider (Araneae), and vegetative communities 1 yr before and 1 yr after a large wildfire swept across an intact grassland in eastern Oregon. Several sites were left unburned after the fire, and a before-after-control-impact study design was used to assess changes within the communities. Fire had no effect on bee or spider abundance, or spider diversity or richness; however, fire significantly increased native bee diversity and richness. In addition, composition of both native bee and spider communities differed significantly between burned and unburned areas 1 yr after the fire. Sheet web spiders (Linyphiidae) and several bee species (primarily large, generalist species) were associated with burned sites. Invasive annual grass and biological soil crust cover decreased significantly in burned sites, but maximum vegetation height and litter cover did not differ significantly among treatments. Forb abundance increased in burned sites; however, species richness of forbs in burned and unburned sites did not differ significantly 1 yr after the fire. Several forbs were indicative of burned areas including non-native species, such as Douglas’ knotweed (Polygonum douglasii) and Russian thistle (Salsola tragus), and native species such as Canadian horseweed (Conyza canadensis), hoary tansyaster (Machaeranthera canescens), and tall willowherb (Epilobium brachycarpum). This study demonstrates that both invertebrate and plant communities show strong short-term responses to wildfire, and our results can be used to inform management of rare habitat and biodiversity in rangelands impacted by wildfire in arid grasslands.

Spider-Web-Inspired Nanocomposite-Modified Separator: Structural and Chemical Cooperativity Inhibiting the Shuttle Effect in Li-S Batteries.

Despite their high theoretical capacity density (1675 mAh g-1), the application of Li-S batteries has been seriously hindered by the shuttle effect of polysulfides. Here, inspired by the working principle of natural spider webs, we synthesized a spider-web-like nanocomposite in which many hollow mesoporous silica (mSiO2) nanospheres/Co nanoparticles were threaded by interconnected nitrogen-doped carbon nanotubes (NCNTs). Then the nanocomposite (denoted as Co/mSiO2-NCNTs) was coated on the commercial separator by a simple infiltration to mitigate the above issue. The intimate combination of three-dimensional conductive networks (NCNTs) with abundant polysulfide adsorbent sites (SiO2 and N)/polysulfide conversion catalysts (Co and Co-N x species) allows the Co/mSiO2-NCNTs coating layer to not only effectively capture polysulfides via both physical confinement and chemical bonding but also accelerate the redox kinetics of polysulfides significantly. Furthermore, the combination of ex situ experiment and theoretical calculation demonstrates that the reversible adsorption/desorption of polysulfides on mSiO2 nanospheres benefits uniform deposition of Li2S2/Li2S on the conductive networks, which contributes to long-term cycling stability. As a result, Li-S batteries with Co/mSiO2-NCNTs-coated separators exhibited both excellent cycling stability and rate performance.

Structure Design and Property of Spider silk-Inspired Shape Memory Materials

Abstract Study on biomimetic materials inspired by natural spider silk has been a hot topic. Inspired by the shape memory behavior of spider silk, thermo-responsive shape memory polypeptide with β-sheet structure was reported, and silk fibroin with β-sheet structure is incorporated into poly(vinyl alcohol) to develop a novel water-sensitive two-way shape memory material. The β-sheet structures act as netpoints responsible for the achievement of good shape recovery ability and high shape fixity. These materials not only possess biocompatibility and nontoxicity, but also have ease to be fabricated, which will be used in many biomedical applications. This study not only provides a new idea for designing intelligent materials, expands the development of bionic and intelligent materials, but also helps to improve the establishment of shape memory theory system and lay a solid theoretical foundation for the further development of shape-memory polymer materials.

High strength structural protein material derived from natural spider silk

High strength structural protein material derived from natural spider silk

Preparation and characterization of Nephila clavipes tubuliform silk gut

Tubuliform silk glands were dissected from Nephila clavipes spiders, and silk gut fibers were produced by immersing the glands in a mild acid solution and subsequent stretching. The tensile properties of the as produced fibers were obtained through tensile tests, and the stress-strain curves were compared with those of naturally spun tubuliform silk fibers. The influence on the mechanical properties of the fibers after immersion in water and drying was also discerned. The microstructure of the silk guts was obtained by X-ray diffraction (XRD) and infrared spectroscopy (FTIR). It was found that the stress-strain curves of the stretched tubuliform silk guts concur with those of their natural counterparts (tubuliform silk fibers).

Hierarchical fibers for water collection inspired by spider silk

Water scarcity plagues two-thirds of the global population. Interestingly, researchers have found that spider silk exhibits excellent water-collection ability owing to its unique structure and chemical components. Based on this characteristic, numerous bioinspired fibers have been fabricated for water collection. Herein, we review the water-collection process for spider silk and recent vital advances in bioinspired fibriform materials, focusing on the water-collection mechanisms of spindle-knot fibers, which exhibit directional droplet transport, hanging mechanism and hanging ability. Also, we evaluated their water-collection abilities on a micro- and macro-scale, which gave a better view for the design of bioinspired water-collection materials. These advances enable the significant use of bioinspired fibers in water collection, which may be applied in several other fields, such as directional transport, tissue engineering, oil-water separation and biosensors.