Nephila clavipes, golden silk spiders, can be found in the southeast United States through Argentina and Peru. Golden silk spiders are most commonly found throughout Peurto Rico (Vargas 1997).

Biogeographic Regions: neotropical (Native )

N. clavipes are highly sexually dimorphic. Females are significantly larger than males ranging from 5 to 6 times the size of the male. Generally, females are 3 inches long. Newly hatched golden silk spiders weigh 0.07g and adult females weigh 4g. They are mostly yellow with an elongated abdomen and long, hairy legs (Higgens 1992).

Golden web spiders are found in areas of high humidity and relatively open space. They live in forest areas along trails and clearing edges (Vargas 1997).

Terrestrial Biomes: forest

N. clavipes feed on small flying insects. Webs constructed by golden silk spiders are used to catch this prey. They can feed on grasshoppers, flies, and other small insects. As the prey is entangled in the strong web, N. clavipes wrap it in silk like a casing.

N. clavipes go through many molting stages. As male N. clavipes reach maturity, they inhabit the webs of females. Males occupy a hub position, which is an area 5cm above the female, and guard her.

Approximately four days before females reach a final molt, they cease web reparation and prey capture. Females are sexually receptive for 48 hours after their final molt has occured. For reproduction to occur among N. clavipes, males must stimulate females and arouse them in order to prevent from becoming prey. Although, in this species of spider, predation on males is not a common occurence. When males approach females for copulation, males vibrate their abdomen and uses a plucking motion. This activity varies depending on the age of females. Once the sperm is transfered, it is stored in the spermathecae. After copulation, females can change web-sites and male partners throughout their adulthood.

After the final molt, females can live 27 days, while males live from 14-21 (Christenson 1985, Brown 1985).

Web glue is strong adhesive: golden orb weaving spider
 

The web glue that coats silk threads of orb weaving spider webs has incredible adhesive strength thanks to glycoproteins.

     
  "The various silks that make up the web of the orb web spiders have been  studied extensively. However, success in prey capture depends as much on  the web glue as on the fibers. Spider silk glue, which is considered  one of the strongest and most effective biological glues, is an aqueous  solution secreted from the orb weaving spider's aggregate glands and  coats the spiral prey capturing threads of their webs. Studies  identified the major component of the glue as microscopic nodules made  of a glycoprotein. This study describes two newly discovered proteins  that form the glue-glycoprotein of the golden orb weaving spider Nephila clavipes.  Our results demonstrate that both proteins contain unique 110 amino  acid repetitive domains that are encoded by opposite strands of the same  DNA sequence. Thus, the genome of the spider encodes two distinct yet  functionally related genes by using both strands of an identical DNA  sequence. Moreover, the closest match for the nonrepetitive region of  one of the proteins is chitin binding proteins. The web glue appears to  have evolved a substantial level of sophistication matching that of the  spider silk fibers." (Choresh et al. 2009:2852)


"Biological materials function in environments where seasonal and even daily changes in conditions have the potential to alter the properties and performance of these materials. This study is the first to examine how changes in environmental humidity affect the extensibility of droplets, which are responsible for the adhesion of viscous capture threads that are produced by over 4000 species of orb-weaving spiders in the Araneoidea clade. These threads form an orb web’s sticky prey capture spiral, which retains insects that strike the web, providing a spider with more time to locate and subdue their prey. Viscous threads are comprised of small, regularly spaced aqueous droplets that surround a pair of supporting axial fibers and are produced by a triad of spigots on each of a spider’s paired posterior spinnerets. The single flagelliform gland spigot of this triad produces an axial fiber and is flanked by two aggregate gland spigots, which coat this fiber with aqueous material. The coated axial fibers merge to form a contiguous pair of fibers surrounded initially by a sheath of viscous material. As a thread absorbs atmospheric moisture in the high humidity of the early morning hours, this material quickly condenses into a regular series of droplets whose size and spacing differ greatly among species.

"The glycoprotein within each droplet that confers thread adhesion is encoded by two genes. The asg1 gene produces a 406-amino-acid protein, whose upstream region has a high proportion of charged amino acids, which are considered hydrophilic, and its repeating downstream region is similar to mucin, known to have adhesive properties. The asg2 gene produces a 714-amino-acid protein, whose upstream region is similar to known chitin-binding proteins, adapting it to adhere to insect exoskeleton, whereas its repeating downstream region has high proline content that resembles that of elastin and flagelliform spider silk, making it elastic. This combination of features confers adhesion, extensibility and hygroscopicity to the glycoprotein–crucial and complementary properties in the context viscous thread performance." (Opell et al. 2011:2988)

  Learn more about this functional adaptation.

Fibers contract and relax: spiders
 

Dragline silk fibers in spider webs help maintain web tension under weight by contracting and relaxing in response to humidity.

         
  "The abrupt halt of a bumble bee's flight when it impacts the almost invisible  threads of an orb web provides an elegant example of the  amazing strength and toughness of spider silk. Spiders depend upon  these properties for survival, yet the impressive performance of silk is not limited  solely to tensile mechanics. Here, we show that silk also exhibits  powerful cyclic contractions, allowing it to act as a high performance mimic  of biological muscles. These contractions are actuated by changes in  humidity alone and repeatedly generate work 50 times greater than the equivalent mass  of human muscle. Although we demonstrate that this response is general  and occurs weakly in diverse hydrophilic materials, the high modulus of spider silk is such that it generates exceptional force. Furthermore,  because this effect already operates at the level of single silk fibers, only 5  µm in diameter, it can easily be scaled across the entire size range at which  biological muscles operate. By contrast, the most successful synthetic  muscles developed so far are driven by electric voltage, such that they cannot  scale easily across large ranges in cross-sectional areas. The potential  applicability of silk  muscles is further enhanced by our finding that silkworm fibers  also exhibit cyclic contraction because they are already available  in commercial quantities. The simplicity of using wet or dry air to drive  the biomimetic silk  muscle fibers and the incredible power generated by silk offer unique possibilities  in designing lightweight and compact actuators for robots  and micro-machines, new sensors, and green energy production." (Agnarsson et al. 2009:1990)

"Spider dragline silk is a model biological polymer for biomimetic  research due to its many desirable and unusual properties. 'Supercontraction' describes the dramatic shrinking of dragline silk  fibers when wetted. In restrained silk fibers, supercontraction  generates substantial stresses of 40–50 MPa above a critical humidity of ~70%  relative humidity (RH). This stress may maintain tension in webs under  the weight of rain or dew and could be used in industry for robotics,  sensor technology, and other applications. Our own findings indicate  that supercontraction can generate stress over a much broader range than  previously reported, from 10 to 140 MPa. Here we show that this  variation in supercontraction stress depends upon the rate at which the  environment reaches the critical level of humidity causing  supercontraction. Slow humidity increase, over several minutes, leads to  relatively low supercontraction stress, while fast humidity increase,  over a few seconds, typically results in higher supercontraction stress.  Slowly supercontracted fibers take up less water and differ in  thermostability from rapidly supercontracted fibers, as shown by  thermogravimetric analysis. This suggests that spider silk achieves  different molecular configurations depending upon the speed at which  supercontraction occurs. Ultimately, rate-dependent supercontraction may  provide a mechanism to tailor the properties of silk or biomimetic  fibers for various applications." (Agnarsson et al. 2009:325)
  Learn more about this functional adaptation.

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There are 2 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
 

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Species: 8
Species With Barcodes: 1

CITES: no special status

An important way in which golden silk spiders benefit humans is with the use of their dragline thread (the silk). N. clavipes, in particular, weave rather strong webs compared to other species of spiders. Currently, there are tests being done on the potential benefits of human use of the dragline thread. The dragline in golden silk spiders surpasses the strength of "Kevlar," which is a fiber used in bullet-proof vests. The dragline thread is biodegradable, stronger than steel, and economically valuable (Unger 1996).