Nephila clavipes
Geographic Range
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
Habitat
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
Physical Description
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).
- Other Physical Features
- ectothermic
- bilateral symmetry
Reproduction
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).
- Key Reproductive Features
- gonochoric/gonochoristic/dioecious (sexes separate)
Behavior
Golden silk spiders construct a strong web for protection from predators and for the capture of prey. The size and structure of the golden silk spider web indicates the defense strategies and developmental changes these spiders go through. The presence of a barrier web, an arrangement of silk on one or more sides of the web, is one useful mechanism for N. clavipes. These barrier webs help block predators such as birds and damselflies. They are also useful for indicating when prey has been caught through vibrations of the web (Christenson 1985, Brown 1985).
Food Habits
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.
Economic Importance for Humans: Positive
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).
Conservation Status
-
- IUCN Red List
- Not Evaluated
-
- CITES
- No special status
Contributors
Stephanie Morse (author), University of Michigan-Ann Arbor, Tanya Dewey (editor), Animal Diversity Web.
Glossary
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
References
Brown, S. 1985. Mating Behavior of the Golden-Orb-Weaving Spider, Nephila clavipes: II. Sperm Capacitation, Sperm Competition, and Fecundity. Journal of Comparative Psychology, 99(2): 167-175.
Christenson, T., S. Brown, P. Wenzl, E. Hill, K. Goist. 1985. Mating Behavior of the Golden-Orb-Weaving Spider, Nephila clavipes: I. Female Receptivity and Male Courtship. Journal of Comparative Psychology, 99(2): 160-166.
Higgens, L. 1992. Developmental Changes in Barrier Web Structure Under Different Levels of Predation Risk in Nephia Clavipes. Journal of Insect Behavior, 5(5): 635-655.
Unger, E. 1996. "Moleculer Spider Silk Technology" (On-line). Accessed March 21, 2000 at http://www.imb-jena.de/www_elmi/molcyto_spid.html.
Vargas, A. 1997. Geographic Distribution of Nephila clavipes. Caribbean Journal of Science, 33(1-2): 114-115.